commit 61d5b7c957e63239f1ebbdbfb94105d53f2dbaa4 (tree)
parent c43ee5bb22298eefc3fae919807f5da8f7be70f1
Author: Jakub Konka <kubkon@jakubkonka.com>
Date: Fri, 21 Jul 2023 17:37:22 +0200
Merge pull request #15823 from kcbanner/dwarf_unwind
Add DWARF unwinding, and an external debug info loader for ELF
Diffstat:
29 files changed, 5603 insertions(+), 515 deletions(-)
diff --git a/lib/std/c.zig b/lib/std/c.zig
@@ -413,6 +413,13 @@ pub extern "c" fn timer_delete(timerid: c.timer_t) c_int;
pub extern "c" fn timer_settime(timerid: c.timer_t, flags: c_int, new_value: *const c.itimerspec, old_value: *c.itimerspec) c_int;
pub extern "c" fn timer_gettime(timerid: c.timer_t, flags: c_int, curr_value: *c.itimerspec) c_int;
+pub usingnamespace if (builtin.os.tag == .linux and builtin.target.isMusl()) struct {
+ // musl does not implement getcontext
+ pub const getcontext = std.os.linux.getcontext;
+} else struct {
+ pub extern "c" fn getcontext(ucp: *std.os.ucontext_t) c_int;
+};
+
pub const max_align_t = if (builtin.abi == .msvc)
f64
else if (builtin.target.isDarwin())
diff --git a/lib/std/c/darwin.zig b/lib/std/c/darwin.zig
@@ -148,12 +148,10 @@ pub const ucontext_t = extern struct {
link: ?*ucontext_t,
mcsize: u64,
mcontext: *mcontext_t,
+ __mcontext_data: mcontext_t,
};
-pub const mcontext_t = extern struct {
- es: arch_bits.exception_state,
- ss: arch_bits.thread_state,
-};
+pub const mcontext_t = arch_bits.mcontext_t;
extern "c" fn __error() *c_int;
pub extern "c" fn NSVersionOfRunTimeLibrary(library_name: [*:0]const u8) u32;
diff --git a/lib/std/c/darwin/aarch64.zig b/lib/std/c/darwin/aarch64.zig
@@ -1,5 +1,12 @@
// See C headers in
// lib/libc/include/aarch64-macos.12-gnu/mach/arm/_structs.h
+// lib/libc/include/aarch64-macos.13-none/arm/_mcontext.h
+
+pub const mcontext_t = extern struct {
+ es: exception_state,
+ ss: thread_state,
+ ns: neon_state,
+};
pub const exception_state = extern struct {
far: u64, // Virtual Fault Address
@@ -17,6 +24,12 @@ pub const thread_state = extern struct {
__pad: u32,
};
+pub const neon_state = extern struct {
+ q: [32]u128,
+ fpsr: u32,
+ fpcr: u32,
+};
+
pub const EXC_TYPES_COUNT = 14;
pub const EXC_MASK_MACHINE = 0;
diff --git a/lib/std/c/darwin/x86_64.zig b/lib/std/c/darwin/x86_64.zig
@@ -1,5 +1,11 @@
const c = @import("../darwin.zig");
+pub const mcontext_t = extern struct {
+ es: exception_state,
+ ss: thread_state,
+ fs: float_state,
+};
+
pub const exception_state = extern struct {
trapno: u16,
cpu: u16,
@@ -31,6 +37,29 @@ pub const thread_state = extern struct {
gs: u64,
};
+const stmm_reg = [16]u8;
+const xmm_reg = [16]u8;
+pub const float_state = extern struct {
+ reserved: [2]c_int,
+ fcw: u16,
+ fsw: u16,
+ ftw: u8,
+ rsrv1: u8,
+ fop: u16,
+ ip: u32,
+ cs: u16,
+ rsrv2: u16,
+ dp: u32,
+ ds: u16,
+ rsrv3: u16,
+ mxcsr: u32,
+ mxcsrmask: u32,
+ stmm: [8]stmm_reg,
+ xmm: [16]xmm_reg,
+ rsrv4: [96]u8,
+ reserved1: c_int,
+};
+
pub const THREAD_STATE = 4;
pub const THREAD_STATE_COUNT: c.mach_msg_type_number_t = @sizeOf(thread_state) / @sizeOf(c_int);
diff --git a/lib/std/coff.zig b/lib/std/coff.zig
@@ -1214,6 +1214,11 @@ pub const Coff = struct {
return Strtab{ .buffer = self.data[offset..][0..size] };
}
+ pub fn strtabRequired(self: *const Coff) bool {
+ for (self.getSectionHeaders()) |*sect_hdr| if (sect_hdr.getName() == null) return true;
+ return false;
+ }
+
pub fn getSectionHeaders(self: *const Coff) []align(1) const SectionHeader {
const coff_header = self.getCoffHeader();
const offset = self.coff_header_offset + @sizeOf(CoffHeader) + coff_header.size_of_optional_header;
@@ -1248,14 +1253,12 @@ pub const Coff = struct {
return null;
}
- pub fn getSectionData(self: *const Coff, comptime name: []const u8) ![]const u8 {
- const sec = self.getSectionByName(name) orelse return error.MissingCoffSection;
+ pub fn getSectionData(self: *const Coff, sec: *align(1) const SectionHeader) []const u8 {
return self.data[sec.pointer_to_raw_data..][0..sec.virtual_size];
}
- // Return an owned slice full of the section data
- pub fn getSectionDataAlloc(self: *const Coff, comptime name: []const u8, allocator: mem.Allocator) ![]u8 {
- const section_data = try self.getSectionData(name);
+ pub fn getSectionDataAlloc(self: *const Coff, sec: *align(1) const SectionHeader, allocator: mem.Allocator) ![]u8 {
+ const section_data = self.getSectionData(sec);
return allocator.dupe(u8, section_data);
}
};
diff --git a/lib/std/debug.zig b/lib/std/debug.zig
@@ -133,10 +133,80 @@ pub fn dumpCurrentStackTrace(start_addr: ?usize) void {
}
}
+pub const have_ucontext = @hasDecl(os.system, "ucontext_t") and
+ (builtin.os.tag != .linux or switch (builtin.cpu.arch) {
+ .mips, .mipsel, .mips64, .mips64el, .riscv64 => false,
+ else => true,
+});
+
+/// Platform-specific thread state. This contains register state, and on some platforms
+/// information about the stack. This is not safe to trivially copy, because some platforms
+/// use internal pointers within this structure. To make a copy, use `copyContext`.
+pub const ThreadContext = blk: {
+ if (native_os == .windows) {
+ break :blk std.os.windows.CONTEXT;
+ } else if (have_ucontext) {
+ break :blk os.ucontext_t;
+ } else {
+ break :blk void;
+ }
+};
+
+/// Copies one context to another, updating any internal pointers
+pub fn copyContext(source: *const ThreadContext, dest: *ThreadContext) void {
+ if (!have_ucontext) return {};
+ dest.* = source.*;
+ relocateContext(dest);
+}
+
+/// Updates any internal pointers in the context to reflect its current location
+pub fn relocateContext(context: *ThreadContext) void {
+ return switch (native_os) {
+ .macos => {
+ context.mcontext = &context.__mcontext_data;
+ },
+ else => {},
+ };
+}
+
+pub const have_getcontext = @hasDecl(os.system, "getcontext") and
+ (builtin.os.tag != .linux or switch (builtin.cpu.arch) {
+ .x86,
+ .x86_64,
+ => true,
+ else => builtin.link_libc and !builtin.target.isMusl(),
+});
+
+/// Capture the current context. The register values in the context will reflect the
+/// state after the platform `getcontext` function returns.
+///
+/// It is valid to call this if the platform doesn't have context capturing support,
+/// in that case false will be returned.
+pub inline fn getContext(context: *ThreadContext) bool {
+ if (native_os == .windows) {
+ context.* = std.mem.zeroes(windows.CONTEXT);
+ windows.ntdll.RtlCaptureContext(context);
+ return true;
+ }
+
+ const result = have_getcontext and os.system.getcontext(context) == 0;
+ if (native_os == .macos) {
+ assert(context.mcsize == @sizeOf(std.c.mcontext_t));
+
+ // On aarch64-macos, the system getcontext doesn't write anything into the pc
+ // register slot, it only writes lr. This makes the context consistent with
+ // other aarch64 getcontext implementations which write the current lr
+ // (where getcontext will return to) into both the lr and pc slot of the context.
+ if (native_arch == .aarch64) context.mcontext.ss.pc = context.mcontext.ss.lr;
+ }
+
+ return result;
+}
+
/// Tries to print the stack trace starting from the supplied base pointer to stderr,
/// unbuffered, and ignores any error returned.
/// TODO multithreaded awareness
-pub fn dumpStackTraceFromBase(bp: usize, ip: usize) void {
+pub fn dumpStackTraceFromBase(context: *const ThreadContext) void {
nosuspend {
if (comptime builtin.target.isWasm()) {
if (native_os == .wasi) {
@@ -156,13 +226,25 @@ pub fn dumpStackTraceFromBase(bp: usize, ip: usize) void {
};
const tty_config = io.tty.detectConfig(io.getStdErr());
if (native_os == .windows) {
- writeCurrentStackTraceWindows(stderr, debug_info, tty_config, ip) catch return;
+ // On x86_64 and aarch64, the stack will be unwound using RtlVirtualUnwind using the context
+ // provided by the exception handler. On x86, RtlVirtualUnwind doesn't exist. Instead, a new backtrace
+ // will be captured and frames prior to the exception will be filtered.
+ // The caveat is that RtlCaptureStackBackTrace does not include the KiUserExceptionDispatcher frame,
+ // which is where the IP in `context` points to, so it can't be used as start_addr.
+ // Instead, start_addr is recovered from the stack.
+ const start_addr = if (builtin.cpu.arch == .x86) @as(*const usize, @ptrFromInt(context.getRegs().bp + 4)).* else null;
+ writeStackTraceWindows(stderr, debug_info, tty_config, context, start_addr) catch return;
return;
}
- printSourceAtAddress(debug_info, stderr, ip, tty_config) catch return;
- var it = StackIterator.init(null, bp);
+ var it = StackIterator.initWithContext(null, debug_info, context) catch return;
+ defer it.deinit();
+ printSourceAtAddress(debug_info, stderr, it.unwind_state.?.dwarf_context.pc, tty_config) catch return;
+
while (it.next()) |return_address| {
+ if (it.getLastError()) |unwind_error|
+ printUnwindError(debug_info, stderr, unwind_error.address, unwind_error.err, tty_config) catch {};
+
// On arm64 macOS, the address of the last frame is 0x0 rather than 0x1 as on x86_64 macOS,
// therefore, we do a check for `return_address == 0` before subtracting 1 from it to avoid
// an overflow. We do not need to signal `StackIterator` as it will correctly detect this
@@ -184,12 +266,12 @@ pub fn captureStackTrace(first_address: ?usize, stack_trace: *std.builtin.StackT
if (native_os == .windows) {
const addrs = stack_trace.instruction_addresses;
const first_addr = first_address orelse {
- stack_trace.index = walkStackWindows(addrs[0..]);
+ stack_trace.index = walkStackWindows(addrs[0..], null);
return;
};
var addr_buf_stack: [32]usize = undefined;
const addr_buf = if (addr_buf_stack.len > addrs.len) addr_buf_stack[0..] else addrs;
- const n = walkStackWindows(addr_buf[0..]);
+ const n = walkStackWindows(addr_buf[0..], null);
const first_index = for (addr_buf[0..n], 0..) |addr, i| {
if (addr == first_addr) {
break i;
@@ -206,7 +288,11 @@ pub fn captureStackTrace(first_address: ?usize, stack_trace: *std.builtin.StackT
}
stack_trace.index = slice.len;
} else {
+ // TODO: This should use the DWARF unwinder if .eh_frame_hdr is available (so that full debug info parsing isn't required).
+ // A new path for loading DebugInfo needs to be created which will only attempt to parse in-memory sections, because
+ // stopping to load other debug info (ie. source line info) from disk here is not required for unwinding.
var it = StackIterator.init(first_address, null);
+ defer it.deinit();
for (stack_trace.instruction_addresses, 0..) |*addr, i| {
addr.* = it.next() orelse {
stack_trace.index = i;
@@ -399,12 +485,27 @@ pub fn writeStackTrace(
}
}
+pub const UnwindError = if (have_ucontext)
+ @typeInfo(@typeInfo(@TypeOf(StackIterator.next_unwind)).Fn.return_type.?).ErrorUnion.error_set
+else
+ void;
+
pub const StackIterator = struct {
// Skip every frame before this address is found.
first_address: ?usize,
// Last known value of the frame pointer register.
fp: usize,
+ // When DebugInfo and a register context is available, this iterator can unwind
+ // stacks with frames that don't use a frame pointer (ie. -fomit-frame-pointer),
+ // using DWARF and MachO unwind info.
+ unwind_state: if (have_ucontext) ?struct {
+ debug_info: *DebugInfo,
+ dwarf_context: DW.UnwindContext,
+ last_error: ?UnwindError = null,
+ failed: bool = false,
+ } else void = if (have_ucontext) null else {},
+
pub fn init(first_address: ?usize, fp: ?usize) StackIterator {
if (native_arch == .sparc64) {
// Flush all the register windows on stack.
@@ -419,6 +520,44 @@ pub const StackIterator = struct {
};
}
+ pub fn initWithContext(first_address: ?usize, debug_info: *DebugInfo, context: *const os.ucontext_t) !StackIterator {
+ // The implementation of DWARF unwinding on aarch64-macos is not complete. However, Apple mandates that
+ // the frame pointer register is always used, so on this platform we can safely use the FP-based unwinder.
+ if (comptime builtin.target.isDarwin() and native_arch == .aarch64) {
+ return init(first_address, context.mcontext.ss.fp);
+ } else {
+ var iterator = init(first_address, null);
+ iterator.unwind_state = .{
+ .debug_info = debug_info,
+ .dwarf_context = try DW.UnwindContext.init(debug_info.allocator, context, &isValidMemory),
+ };
+
+ return iterator;
+ }
+ }
+
+ pub fn deinit(self: *StackIterator) void {
+ if (have_ucontext and self.unwind_state != null) self.unwind_state.?.dwarf_context.deinit();
+ }
+
+ pub fn getLastError(self: *StackIterator) ?struct {
+ err: UnwindError,
+ address: usize,
+ } {
+ if (!have_ucontext) return null;
+ if (self.unwind_state) |*unwind_state| {
+ if (unwind_state.last_error) |err| {
+ unwind_state.last_error = null;
+ return .{
+ .err = err,
+ .address = unwind_state.dwarf_context.pc,
+ };
+ }
+ }
+
+ return null;
+ }
+
// Offset of the saved BP wrt the frame pointer.
const fp_offset = if (native_arch.isRISCV())
// On RISC-V the frame pointer points to the top of the saved register
@@ -461,6 +600,7 @@ pub const StackIterator = struct {
if (native_os == .freestanding) return true;
const aligned_address = address & ~@as(usize, @intCast((mem.page_size - 1)));
+ if (aligned_address == 0) return false;
const aligned_memory = @as([*]align(mem.page_size) u8, @ptrFromInt(aligned_address))[0..mem.page_size];
if (native_os != .windows) {
@@ -500,7 +640,49 @@ pub const StackIterator = struct {
}
}
+ fn next_unwind(self: *StackIterator) !usize {
+ const unwind_state = &self.unwind_state.?;
+ const module = try unwind_state.debug_info.getModuleForAddress(unwind_state.dwarf_context.pc);
+ switch (native_os) {
+ .macos, .ios, .watchos, .tvos => {
+ // __unwind_info is a requirement for unwinding on Darwin. It may fall back to DWARF, but unwinding
+ // via DWARF before attempting to use the compact unwind info will produce incorrect results.
+ if (module.unwind_info) |unwind_info| {
+ if (DW.unwindFrameMachO(&unwind_state.dwarf_context, unwind_info, module.eh_frame, module.base_address)) |return_address| {
+ return return_address;
+ } else |err| {
+ if (err != error.RequiresDWARFUnwind) return err;
+ }
+ } else return error.MissingUnwindInfo;
+ },
+ else => {},
+ }
+
+ if (try module.getDwarfInfoForAddress(unwind_state.debug_info.allocator, unwind_state.dwarf_context.pc)) |di| {
+ return di.unwindFrame(&unwind_state.dwarf_context, null);
+ } else return error.MissingDebugInfo;
+ }
+
fn next_internal(self: *StackIterator) ?usize {
+ if (have_ucontext) {
+ if (self.unwind_state) |*unwind_state| {
+ if (!unwind_state.failed) {
+ if (unwind_state.dwarf_context.pc == 0) return null;
+ if (self.next_unwind()) |return_address| {
+ self.fp = unwind_state.dwarf_context.getFp() catch 0;
+ return return_address;
+ } else |err| {
+ unwind_state.last_error = err;
+ unwind_state.failed = true;
+
+ // Fall back to fp-based unwinding on the first failure.
+ // We can't attempt it again for other modules higher in the
+ // stack because the full register state won't have been unwound.
+ }
+ }
+ }
+ }
+
const fp = if (comptime native_arch.isSPARC())
// On SPARC the offset is positive. (!)
math.add(usize, self.fp, fp_offset) catch return null
@@ -537,11 +719,21 @@ pub fn writeCurrentStackTrace(
tty_config: io.tty.Config,
start_addr: ?usize,
) !void {
+ var context: ThreadContext = undefined;
+ const has_context = getContext(&context);
if (native_os == .windows) {
- return writeCurrentStackTraceWindows(out_stream, debug_info, tty_config, start_addr);
+ return writeStackTraceWindows(out_stream, debug_info, tty_config, &context, start_addr);
}
- var it = StackIterator.init(start_addr, null);
+
+ var it = (if (has_context) blk: {
+ break :blk StackIterator.initWithContext(start_addr, debug_info, &context) catch null;
+ } else null) orelse StackIterator.init(start_addr, null);
+ defer it.deinit();
+
while (it.next()) |return_address| {
+ if (it.getLastError()) |unwind_error|
+ try printUnwindError(debug_info, out_stream, unwind_error.address, unwind_error.err, tty_config);
+
// On arm64 macOS, the address of the last frame is 0x0 rather than 0x1 as on x86_64 macOS,
// therefore, we do a check for `return_address == 0` before subtracting 1 from it to avoid
// an overflow. We do not need to signal `StackIterator` as it will correctly detect this
@@ -552,7 +744,7 @@ pub fn writeCurrentStackTrace(
}
}
-pub noinline fn walkStackWindows(addresses: []usize) usize {
+pub noinline fn walkStackWindows(addresses: []usize, existing_context: ?*const windows.CONTEXT) usize {
if (builtin.cpu.arch == .x86) {
// RtlVirtualUnwind doesn't exist on x86
return windows.ntdll.RtlCaptureStackBackTrace(0, addresses.len, @as(**anyopaque, @ptrCast(addresses.ptr)), null);
@@ -560,8 +752,13 @@ pub noinline fn walkStackWindows(addresses: []usize) usize {
const tib = @as(*const windows.NT_TIB, @ptrCast(&windows.teb().Reserved1));
- var context: windows.CONTEXT = std.mem.zeroes(windows.CONTEXT);
- windows.ntdll.RtlCaptureContext(&context);
+ var context: windows.CONTEXT = undefined;
+ if (existing_context) |context_ptr| {
+ context = context_ptr.*;
+ } else {
+ context = std.mem.zeroes(windows.CONTEXT);
+ windows.ntdll.RtlCaptureContext(&context);
+ }
var i: usize = 0;
var image_base: usize = undefined;
@@ -603,14 +800,15 @@ pub noinline fn walkStackWindows(addresses: []usize) usize {
return i;
}
-pub fn writeCurrentStackTraceWindows(
+pub fn writeStackTraceWindows(
out_stream: anytype,
debug_info: *DebugInfo,
tty_config: io.tty.Config,
+ context: *const windows.CONTEXT,
start_addr: ?usize,
) !void {
var addr_buf: [1024]usize = undefined;
- const n = walkStackWindows(addr_buf[0..]);
+ const n = walkStackWindows(addr_buf[0..], context);
const addrs = addr_buf[0..n];
var start_i: usize = if (start_addr) |saddr| blk: {
for (addrs, 0..) |addr, i| {
@@ -681,6 +879,13 @@ fn printUnknownSource(debug_info: *DebugInfo, out_stream: anytype, address: usiz
);
}
+pub fn printUnwindError(debug_info: *DebugInfo, out_stream: anytype, address: usize, err: UnwindError, tty_config: io.tty.Config) !void {
+ const module_name = debug_info.getModuleNameForAddress(address) orelse "???";
+ try tty_config.setColor(out_stream, .dim);
+ try out_stream.print("Unwind information for `{s}:0x{x}` was not available ({}), trace may be incomplete\n\n", .{ module_name, address, err });
+ try tty_config.setColor(out_stream, .reset);
+}
+
pub fn printSourceAtAddress(debug_info: *DebugInfo, out_stream: anytype, address: usize, tty_config: io.tty.Config) !void {
const module = debug_info.getModuleForAddress(address) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => return printUnknownSource(debug_info, out_stream, address, tty_config),
@@ -779,12 +984,8 @@ pub fn openSelfDebugInfo(allocator: mem.Allocator) OpenSelfDebugInfoError!DebugI
}
}
-fn readCoffDebugInfo(allocator: mem.Allocator, coff_bytes: []const u8) !ModuleDebugInfo {
+fn readCoffDebugInfo(allocator: mem.Allocator, coff_obj: *coff.Coff) !ModuleDebugInfo {
nosuspend {
- const coff_obj = try allocator.create(coff.Coff);
- defer allocator.destroy(coff_obj);
- coff_obj.* = try coff.Coff.init(coff_bytes);
-
var di = ModuleDebugInfo{
.base_address = undefined,
.coff_image_base = coff_obj.getImageBase(),
@@ -792,62 +993,35 @@ fn readCoffDebugInfo(allocator: mem.Allocator, coff_bytes: []const u8) !ModuleDe
.debug_data = undefined,
};
- if (coff_obj.getSectionByName(".debug_info")) |sec| {
+ if (coff_obj.getSectionByName(".debug_info")) |_| {
// This coff file has embedded DWARF debug info
- _ = sec;
-
- const debug_info = coff_obj.getSectionDataAlloc(".debug_info", allocator) catch return error.MissingDebugInfo;
- errdefer allocator.free(debug_info);
- const debug_abbrev = coff_obj.getSectionDataAlloc(".debug_abbrev", allocator) catch return error.MissingDebugInfo;
- errdefer allocator.free(debug_abbrev);
- const debug_str = coff_obj.getSectionDataAlloc(".debug_str", allocator) catch return error.MissingDebugInfo;
- errdefer allocator.free(debug_str);
- const debug_line = coff_obj.getSectionDataAlloc(".debug_line", allocator) catch return error.MissingDebugInfo;
- errdefer allocator.free(debug_line);
-
- const debug_str_offsets = coff_obj.getSectionDataAlloc(".debug_str_offsets", allocator) catch null;
- const debug_line_str = coff_obj.getSectionDataAlloc(".debug_line_str", allocator) catch null;
- const debug_ranges = coff_obj.getSectionDataAlloc(".debug_ranges", allocator) catch null;
- const debug_loclists = coff_obj.getSectionDataAlloc(".debug_loclists", allocator) catch null;
- const debug_rnglists = coff_obj.getSectionDataAlloc(".debug_rnglists", allocator) catch null;
- const debug_addr = coff_obj.getSectionDataAlloc(".debug_addr", allocator) catch null;
- const debug_names = coff_obj.getSectionDataAlloc(".debug_names", allocator) catch null;
- const debug_frame = coff_obj.getSectionDataAlloc(".debug_frame", allocator) catch null;
+ var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
+ errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
+
+ inline for (@typeInfo(DW.DwarfSection).Enum.fields, 0..) |section, i| {
+ sections[i] = if (coff_obj.getSectionByName("." ++ section.name)) |section_header| blk: {
+ break :blk .{
+ .data = try coff_obj.getSectionDataAlloc(section_header, allocator),
+ .virtual_address = section_header.virtual_address,
+ .owned = true,
+ };
+ } else null;
+ }
var dwarf = DW.DwarfInfo{
.endian = native_endian,
- .debug_info = debug_info,
- .debug_abbrev = debug_abbrev,
- .debug_str = debug_str,
- .debug_str_offsets = debug_str_offsets,
- .debug_line = debug_line,
- .debug_line_str = debug_line_str,
- .debug_ranges = debug_ranges,
- .debug_loclists = debug_loclists,
- .debug_rnglists = debug_rnglists,
- .debug_addr = debug_addr,
- .debug_names = debug_names,
- .debug_frame = debug_frame,
- };
-
- DW.openDwarfDebugInfo(&dwarf, allocator) catch |err| {
- if (debug_str_offsets) |d| allocator.free(d);
- if (debug_line_str) |d| allocator.free(d);
- if (debug_ranges) |d| allocator.free(d);
- if (debug_loclists) |d| allocator.free(d);
- if (debug_rnglists) |d| allocator.free(d);
- if (debug_addr) |d| allocator.free(d);
- if (debug_names) |d| allocator.free(d);
- if (debug_frame) |d| allocator.free(d);
- return err;
+ .sections = sections,
+ .is_macho = false,
};
+ try DW.openDwarfDebugInfo(&dwarf, allocator);
di.debug_data = PdbOrDwarf{ .dwarf = dwarf };
return di;
}
// Only used by pdb path
di.coff_section_headers = try coff_obj.getSectionHeadersAlloc(allocator);
+ errdefer allocator.free(di.coff_section_headers);
var path_buf: [windows.MAX_PATH]u8 = undefined;
const len = try coff_obj.getPdbPath(path_buf[0..]);
@@ -877,13 +1051,35 @@ fn chopSlice(ptr: []const u8, offset: u64, size: u64) error{Overflow}![]const u8
return ptr[start..end];
}
-/// This takes ownership of elf_file: users of this function should not close
-/// it themselves, even on error.
-/// TODO it's weird to take ownership even on error, rework this code.
-pub fn readElfDebugInfo(allocator: mem.Allocator, elf_file: File) !ModuleDebugInfo {
+/// Reads debug info from an ELF file, or the current binary if none in specified.
+/// If the required sections aren't present but a reference to external debug info is,
+/// then this this function will recurse to attempt to load the debug sections from
+/// an external file.
+pub fn readElfDebugInfo(
+ allocator: mem.Allocator,
+ elf_filename: ?[]const u8,
+ build_id: ?[]const u8,
+ expected_crc: ?u32,
+ parent_sections: *DW.DwarfInfo.SectionArray,
+ parent_mapped_mem: ?[]align(mem.page_size) const u8,
+) !ModuleDebugInfo {
nosuspend {
+
+ // TODO https://github.com/ziglang/zig/issues/5525
+ const elf_file = (if (elf_filename) |filename| blk: {
+ break :blk if (fs.path.isAbsolute(filename))
+ fs.openFileAbsolute(filename, .{ .intended_io_mode = .blocking })
+ else
+ fs.cwd().openFile(filename, .{ .intended_io_mode = .blocking });
+ } else fs.openSelfExe(.{ .intended_io_mode = .blocking })) catch |err| switch (err) {
+ error.FileNotFound => return error.MissingDebugInfo,
+ else => return err,
+ };
+
const mapped_mem = try mapWholeFile(elf_file);
- const hdr = @as(*const elf.Ehdr, @ptrCast(&mapped_mem[0]));
+ if (expected_crc) |crc| if (crc != std.hash.crc.Crc32SmallWithPoly(.IEEE).hash(mapped_mem)) return error.InvalidDebugInfo;
+
+ const hdr: *const elf.Ehdr = @ptrCast(&mapped_mem[0]);
if (!mem.eql(u8, hdr.e_ident[0..4], elf.MAGIC)) return error.InvalidElfMagic;
if (hdr.e_ident[elf.EI_VERSION] != 1) return error.InvalidElfVersion;
@@ -896,73 +1092,152 @@ pub fn readElfDebugInfo(allocator: mem.Allocator, elf_file: File) !ModuleDebugIn
const shoff = hdr.e_shoff;
const str_section_off = shoff + @as(u64, hdr.e_shentsize) * @as(u64, hdr.e_shstrndx);
- const str_shdr: *const elf.Shdr = @ptrCast(@alignCast(
- &mapped_mem[math.cast(usize, str_section_off) orelse return error.Overflow],
- ));
- const header_strings = mapped_mem[str_shdr.sh_offset .. str_shdr.sh_offset + str_shdr.sh_size];
+ const str_shdr: *const elf.Shdr = @ptrCast(@alignCast(&mapped_mem[math.cast(usize, str_section_off) orelse return error.Overflow]));
+ const header_strings = mapped_mem[str_shdr.sh_offset..][0..str_shdr.sh_size];
const shdrs = @as(
[*]const elf.Shdr,
@ptrCast(@alignCast(&mapped_mem[shoff])),
)[0..hdr.e_shnum];
- var opt_debug_info: ?[]const u8 = null;
- var opt_debug_abbrev: ?[]const u8 = null;
- var opt_debug_str: ?[]const u8 = null;
- var opt_debug_str_offsets: ?[]const u8 = null;
- var opt_debug_line: ?[]const u8 = null;
- var opt_debug_line_str: ?[]const u8 = null;
- var opt_debug_ranges: ?[]const u8 = null;
- var opt_debug_loclists: ?[]const u8 = null;
- var opt_debug_rnglists: ?[]const u8 = null;
- var opt_debug_addr: ?[]const u8 = null;
- var opt_debug_names: ?[]const u8 = null;
- var opt_debug_frame: ?[]const u8 = null;
+ var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
- for (shdrs) |*shdr| {
- if (shdr.sh_type == elf.SHT_NULL) continue;
+ // Combine section list. This takes ownership over any owned sections from the parent scope.
+ for (parent_sections, §ions) |*parent, *section| {
+ if (parent.*) |*p| {
+ section.* = p.*;
+ p.owned = false;
+ }
+ }
+ errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
+
+ var separate_debug_filename: ?[]const u8 = null;
+ var separate_debug_crc: ?u32 = null;
+ for (shdrs) |*shdr| {
+ if (shdr.sh_type == elf.SHT_NULL or shdr.sh_type == elf.SHT_NOBITS) continue;
const name = mem.sliceTo(header_strings[shdr.sh_name..], 0);
- if (mem.eql(u8, name, ".debug_info")) {
- opt_debug_info = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_abbrev")) {
- opt_debug_abbrev = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_str")) {
- opt_debug_str = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_str_offsets")) {
- opt_debug_str_offsets = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_line")) {
- opt_debug_line = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_line_str")) {
- opt_debug_line_str = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_ranges")) {
- opt_debug_ranges = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_loclists")) {
- opt_debug_loclists = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_rnglists")) {
- opt_debug_rnglists = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_addr")) {
- opt_debug_addr = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_names")) {
- opt_debug_names = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
- } else if (mem.eql(u8, name, ".debug_frame")) {
- opt_debug_frame = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
+
+ if (mem.eql(u8, name, ".gnu_debuglink")) {
+ const gnu_debuglink = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
+ const debug_filename = mem.sliceTo(@as([*:0]const u8, @ptrCast(gnu_debuglink.ptr)), 0);
+ const crc_offset = mem.alignForward(usize, @intFromPtr(&debug_filename[debug_filename.len]) + 1, 4) - @intFromPtr(gnu_debuglink.ptr);
+ const crc_bytes = gnu_debuglink[crc_offset .. crc_offset + 4];
+ separate_debug_crc = mem.readIntSliceNative(u32, crc_bytes);
+ separate_debug_filename = debug_filename;
+ continue;
+ }
+
+ var section_index: ?usize = null;
+ inline for (@typeInfo(DW.DwarfSection).Enum.fields, 0..) |section, i| {
+ if (mem.eql(u8, "." ++ section.name, name)) section_index = i;
+ }
+ if (section_index == null) continue;
+ if (sections[section_index.?] != null) continue;
+
+ const section_bytes = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
+ sections[section_index.?] = if ((shdr.sh_flags & elf.SHF_COMPRESSED) > 0) blk: {
+ var section_stream = io.fixedBufferStream(section_bytes);
+ var section_reader = section_stream.reader();
+ const chdr = section_reader.readStruct(elf.Chdr) catch continue;
+ if (chdr.ch_type != .ZLIB) continue;
+
+ var zlib_stream = std.compress.zlib.decompressStream(allocator, section_stream.reader()) catch continue;
+ defer zlib_stream.deinit();
+
+ var decompressed_section = try allocator.alloc(u8, chdr.ch_size);
+ errdefer allocator.free(decompressed_section);
+
+ const read = zlib_stream.reader().readAll(decompressed_section) catch continue;
+ assert(read == decompressed_section.len);
+
+ break :blk .{
+ .data = decompressed_section,
+ .virtual_address = shdr.sh_addr,
+ .owned = true,
+ };
+ } else .{
+ .data = section_bytes,
+ .virtual_address = shdr.sh_addr,
+ .owned = false,
+ };
+ }
+
+ const missing_debug_info =
+ sections[@intFromEnum(DW.DwarfSection.debug_info)] == null or
+ sections[@intFromEnum(DW.DwarfSection.debug_abbrev)] == null or
+ sections[@intFromEnum(DW.DwarfSection.debug_str)] == null or
+ sections[@intFromEnum(DW.DwarfSection.debug_line)] == null;
+
+ // Attempt to load debug info from an external file
+ // See: https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
+ if (missing_debug_info) {
+
+ // Only allow one level of debug info nesting
+ if (parent_mapped_mem) |_| {
+ return error.MissingDebugInfo;
+ }
+
+ const global_debug_directories = [_][]const u8{
+ "/usr/lib/debug",
+ };
+
+ // <global debug directory>/.build-id/<2-character id prefix>/<id remainder>.debug
+ if (build_id) |id| blk: {
+ if (id.len < 3) break :blk;
+
+ // Either md5 (16 bytes) or sha1 (20 bytes) are used here in practice
+ const extension = ".debug";
+ var id_prefix_buf: [2]u8 = undefined;
+ var filename_buf: [38 + extension.len]u8 = undefined;
+
+ _ = std.fmt.bufPrint(&id_prefix_buf, "{s}", .{std.fmt.fmtSliceHexLower(id[0..1])}) catch unreachable;
+ const filename = std.fmt.bufPrint(
+ &filename_buf,
+ "{s}" ++ extension,
+ .{std.fmt.fmtSliceHexLower(id[1..])},
+ ) catch break :blk;
+
+ for (global_debug_directories) |global_directory| {
+ const path = try fs.path.join(allocator, &.{ global_directory, ".build-id", &id_prefix_buf, filename });
+ defer allocator.free(path);
+
+ return readElfDebugInfo(allocator, path, null, separate_debug_crc, §ions, mapped_mem) catch continue;
+ }
+ }
+
+ // use the path from .gnu_debuglink, in the same search order as gdb
+ if (separate_debug_filename) |separate_filename| blk: {
+ if (elf_filename != null and mem.eql(u8, elf_filename.?, separate_filename)) return error.MissingDebugInfo;
+
+ // <cwd>/<gnu_debuglink>
+ if (readElfDebugInfo(allocator, separate_filename, null, separate_debug_crc, §ions, mapped_mem)) |debug_info| return debug_info else |_| {}
+
+ // <cwd>/.debug/<gnu_debuglink>
+ {
+ const path = try fs.path.join(allocator, &.{ ".debug", separate_filename });
+ defer allocator.free(path);
+
+ if (readElfDebugInfo(allocator, path, null, separate_debug_crc, §ions, mapped_mem)) |debug_info| return debug_info else |_| {}
+ }
+
+ var cwd_buf: [fs.MAX_PATH_BYTES]u8 = undefined;
+ const cwd_path = fs.cwd().realpath("", &cwd_buf) catch break :blk;
+
+ // <global debug directory>/<absolute folder of current binary>/<gnu_debuglink>
+ for (global_debug_directories) |global_directory| {
+ const path = try fs.path.join(allocator, &.{ global_directory, cwd_path, separate_filename });
+ defer allocator.free(path);
+ if (readElfDebugInfo(allocator, path, null, separate_debug_crc, §ions, mapped_mem)) |debug_info| return debug_info else |_| {}
+ }
}
+
+ return error.MissingDebugInfo;
}
var di = DW.DwarfInfo{
.endian = endian,
- .debug_info = opt_debug_info orelse return error.MissingDebugInfo,
- .debug_abbrev = opt_debug_abbrev orelse return error.MissingDebugInfo,
- .debug_str = opt_debug_str orelse return error.MissingDebugInfo,
- .debug_str_offsets = opt_debug_str_offsets,
- .debug_line = opt_debug_line orelse return error.MissingDebugInfo,
- .debug_line_str = opt_debug_line_str,
- .debug_ranges = opt_debug_ranges,
- .debug_loclists = opt_debug_loclists,
- .debug_rnglists = opt_debug_rnglists,
- .debug_addr = opt_debug_addr,
- .debug_names = opt_debug_names,
- .debug_frame = opt_debug_frame,
+ .sections = sections,
+ .is_macho = false,
};
try DW.openDwarfDebugInfo(&di, allocator);
@@ -970,7 +1245,8 @@ pub fn readElfDebugInfo(allocator: mem.Allocator, elf_file: File) !ModuleDebugIn
return ModuleDebugInfo{
.base_address = undefined,
.dwarf = di,
- .mapped_memory = mapped_mem,
+ .mapped_memory = parent_mapped_mem orelse mapped_mem,
+ .external_mapped_memory = if (parent_mapped_mem != null) mapped_mem else null,
};
}
}
@@ -1094,6 +1370,7 @@ fn readMachODebugInfo(allocator: mem.Allocator, macho_file: File) !ModuleDebugIn
return ModuleDebugInfo{
.base_address = undefined,
+ .vmaddr_slide = undefined,
.mapped_memory = mapped_mem,
.ofiles = ModuleDebugInfo.OFileTable.init(allocator),
.symbols = symbols,
@@ -1180,6 +1457,21 @@ pub const WindowsModuleInfo = struct {
base_address: usize,
size: u32,
name: []const u8,
+ handle: windows.HMODULE,
+
+ // Set when the image file needed to be mapped from disk
+ mapped_file: ?struct {
+ file: File,
+ section_handle: windows.HANDLE,
+ section_view: []const u8,
+
+ pub fn deinit(self: @This()) void {
+ const process_handle = windows.kernel32.GetCurrentProcess();
+ assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @constCast(@ptrCast(self.section_view.ptr))) == .SUCCESS);
+ windows.CloseHandle(self.section_handle);
+ self.file.close();
+ }
+ } = null,
};
pub const DebugInfo = struct {
@@ -1195,6 +1487,8 @@ pub const DebugInfo = struct {
};
if (native_os == .windows) {
+ errdefer debug_info.modules.deinit(allocator);
+
const handle = windows.kernel32.CreateToolhelp32Snapshot(windows.TH32CS_SNAPMODULE | windows.TH32CS_SNAPMODULE32, 0);
if (handle == windows.INVALID_HANDLE_VALUE) {
switch (windows.kernel32.GetLastError()) {
@@ -1212,9 +1506,16 @@ pub const DebugInfo = struct {
var module_valid = true;
while (module_valid) {
const module_info = try debug_info.modules.addOne(allocator);
- module_info.base_address = @intFromPtr(module_entry.modBaseAddr);
- module_info.size = module_entry.modBaseSize;
- module_info.name = allocator.dupe(u8, mem.sliceTo(&module_entry.szModule, 0)) catch &.{};
+ const name = allocator.dupe(u8, mem.sliceTo(&module_entry.szModule, 0)) catch &.{};
+ errdefer allocator.free(name);
+
+ module_info.* = .{
+ .base_address = @intFromPtr(module_entry.modBaseAddr),
+ .size = module_entry.modBaseSize,
+ .name = name,
+ .handle = module_entry.hModule,
+ };
+
module_valid = windows.kernel32.Module32Next(handle, &module_entry) == 1;
}
}
@@ -1233,6 +1534,7 @@ pub const DebugInfo = struct {
if (native_os == .windows) {
for (self.modules.items) |module| {
self.allocator.free(module.name);
+ if (module.mapped_file) |mapped_file| mapped_file.deinit();
}
self.modules.deinit(self.allocator);
}
@@ -1252,9 +1554,12 @@ pub const DebugInfo = struct {
}
}
+ // Returns the module name for a given address.
+ // This can be called when getModuleForAddress fails, so implementations should provide
+ // a path that doesn't rely on any side-effects of a prior successful module lookup.
pub fn getModuleNameForAddress(self: *DebugInfo, address: usize) ?[]const u8 {
if (comptime builtin.target.isDarwin()) {
- return null;
+ return self.lookupModuleNameDyld(address);
} else if (native_os == .windows) {
return self.lookupModuleNameWin32(address);
} else if (native_os == .haiku) {
@@ -1262,7 +1567,7 @@ pub const DebugInfo = struct {
} else if (comptime builtin.target.isWasm()) {
return null;
} else {
- return null;
+ return self.lookupModuleNameDl(address);
}
}
@@ -1271,11 +1576,10 @@ pub const DebugInfo = struct {
var i: u32 = 0;
while (i < image_count) : (i += 1) {
- const base_address = std.c._dyld_get_image_vmaddr_slide(i);
-
- if (address < base_address) continue;
-
const header = std.c._dyld_get_image_header(i) orelse continue;
+ const base_address = @intFromPtr(header);
+ if (address < base_address) continue;
+ const vmaddr_slide = std.c._dyld_get_image_vmaddr_slide(i);
var it = macho.LoadCommandIterator{
.ncmds = header.ncmds,
@@ -1284,18 +1588,29 @@ pub const DebugInfo = struct {
@ptrFromInt(@intFromPtr(header) + @sizeOf(macho.mach_header_64)),
)[0..header.sizeofcmds]),
};
+
+ var unwind_info: ?[]const u8 = null;
+ var eh_frame: ?[]const u8 = null;
while (it.next()) |cmd| switch (cmd.cmd()) {
.SEGMENT_64 => {
const segment_cmd = cmd.cast(macho.segment_command_64).?;
- const rebased_address = address - base_address;
- const seg_start = segment_cmd.vmaddr;
- const seg_end = seg_start + segment_cmd.vmsize;
+ if (!mem.eql(u8, "__TEXT", segment_cmd.segName())) continue;
- if (rebased_address >= seg_start and rebased_address < seg_end) {
+ const seg_start = segment_cmd.vmaddr + vmaddr_slide;
+ const seg_end = seg_start + segment_cmd.vmsize;
+ if (address >= seg_start and address < seg_end) {
if (self.address_map.get(base_address)) |obj_di| {
return obj_di;
}
+ for (cmd.getSections()) |sect| {
+ if (mem.eql(u8, "__unwind_info", sect.sectName())) {
+ unwind_info = @as([*]const u8, @ptrFromInt(sect.addr + vmaddr_slide))[0..sect.size];
+ } else if (mem.eql(u8, "__eh_frame", sect.sectName())) {
+ eh_frame = @as([*]const u8, @ptrFromInt(sect.addr + vmaddr_slide))[0..sect.size];
+ }
+ }
+
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
@@ -1308,6 +1623,9 @@ pub const DebugInfo = struct {
};
obj_di.* = try readMachODebugInfo(self.allocator, macho_file);
obj_di.base_address = base_address;
+ obj_di.vmaddr_slide = vmaddr_slide;
+ obj_di.unwind_info = unwind_info;
+ obj_di.eh_frame = eh_frame;
try self.address_map.putNoClobber(base_address, obj_di);
@@ -1321,18 +1639,124 @@ pub const DebugInfo = struct {
return error.MissingDebugInfo;
}
+ fn lookupModuleNameDyld(self: *DebugInfo, address: usize) ?[]const u8 {
+ _ = self;
+ const image_count = std.c._dyld_image_count();
+
+ var i: u32 = 0;
+ while (i < image_count) : (i += 1) {
+ const header = std.c._dyld_get_image_header(i) orelse continue;
+ const base_address = @intFromPtr(header);
+ if (address < base_address) continue;
+ const vmaddr_slide = std.c._dyld_get_image_vmaddr_slide(i);
+
+ var it = macho.LoadCommandIterator{
+ .ncmds = header.ncmds,
+ .buffer = @alignCast(@as(
+ [*]u8,
+ @ptrFromInt(@intFromPtr(header) + @sizeOf(macho.mach_header_64)),
+ )[0..header.sizeofcmds]),
+ };
+
+ while (it.next()) |cmd| switch (cmd.cmd()) {
+ .SEGMENT_64 => {
+ const segment_cmd = cmd.cast(macho.segment_command_64).?;
+ if (!mem.eql(u8, "__TEXT", segment_cmd.segName())) continue;
+
+ const original_address = address - vmaddr_slide;
+ const seg_start = segment_cmd.vmaddr;
+ const seg_end = seg_start + segment_cmd.vmsize;
+ if (original_address >= seg_start and original_address < seg_end) {
+ return fs.path.basename(mem.sliceTo(std.c._dyld_get_image_name(i), 0));
+ }
+ },
+ else => {},
+ };
+ }
+
+ return null;
+ }
+
fn lookupModuleWin32(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
- for (self.modules.items) |module| {
+ for (self.modules.items) |*module| {
if (address >= module.base_address and address < module.base_address + module.size) {
if (self.address_map.get(module.base_address)) |obj_di| {
return obj_di;
}
- const mapped_module = @as([*]const u8, @ptrFromInt(module.base_address))[0..module.size];
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
- obj_di.* = try readCoffDebugInfo(self.allocator, mapped_module);
+ const mapped_module = @as([*]const u8, @ptrFromInt(module.base_address))[0..module.size];
+ var coff_obj = try coff.Coff.init(mapped_module);
+
+ // The string table is not mapped into memory by the loader, so if a section name is in the
+ // string table then we have to map the full image file from disk. This can happen when
+ // a binary is produced with -gdwarf, since the section names are longer than 8 bytes.
+ if (coff_obj.strtabRequired()) {
+ var name_buffer: [windows.PATH_MAX_WIDE + 4:0]u16 = undefined;
+ // openFileAbsoluteW requires the prefix to be present
+ mem.copy(u16, name_buffer[0..4], &[_]u16{ '\\', '?', '?', '\\' });
+
+ const process_handle = windows.kernel32.GetCurrentProcess();
+ const len = windows.kernel32.K32GetModuleFileNameExW(
+ process_handle,
+ module.handle,
+ @ptrCast(&name_buffer[4]),
+ windows.PATH_MAX_WIDE,
+ );
+
+ if (len == 0) return error.MissingDebugInfo;
+ const coff_file = fs.openFileAbsoluteW(name_buffer[0 .. len + 4 :0], .{}) catch |err| switch (err) {
+ error.FileNotFound => return error.MissingDebugInfo,
+ else => return err,
+ };
+ errdefer coff_file.close();
+
+ var section_handle: windows.HANDLE = undefined;
+ const create_section_rc = windows.ntdll.NtCreateSection(
+ §ion_handle,
+ windows.STANDARD_RIGHTS_REQUIRED | windows.SECTION_QUERY | windows.SECTION_MAP_READ,
+ null,
+ null,
+ windows.PAGE_READONLY,
+ // The documentation states that if no AllocationAttribute is specified, then SEC_COMMIT is the default.
+ // In practice, this isn't the case and specifying 0 will result in INVALID_PARAMETER_6.
+ windows.SEC_COMMIT,
+ coff_file.handle,
+ );
+ if (create_section_rc != .SUCCESS) return error.MissingDebugInfo;
+ errdefer windows.CloseHandle(section_handle);
+
+ var coff_len: usize = 0;
+ var base_ptr: usize = 0;
+ const map_section_rc = windows.ntdll.NtMapViewOfSection(
+ section_handle,
+ process_handle,
+ @ptrCast(&base_ptr),
+ null,
+ 0,
+ null,
+ &coff_len,
+ .ViewUnmap,
+ 0,
+ windows.PAGE_READONLY,
+ );
+ if (map_section_rc != .SUCCESS) return error.MissingDebugInfo;
+ errdefer assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @ptrFromInt(base_ptr)) == .SUCCESS);
+
+ const section_view = @as([*]const u8, @ptrFromInt(base_ptr))[0..coff_len];
+ coff_obj = try coff.Coff.init(section_view);
+
+ module.mapped_file = .{
+ .file = coff_file,
+ .section_handle = section_handle,
+ .section_view = section_view,
+ };
+ }
+ errdefer if (module.mapped_file) |mapped_file| mapped_file.deinit();
+
+ obj_di.* = try readCoffDebugInfo(self.allocator, &coff_obj);
obj_di.base_address = module.base_address;
try self.address_map.putNoClobber(module.base_address, obj_di);
@@ -1352,6 +1776,44 @@ pub const DebugInfo = struct {
return null;
}
+ fn lookupModuleNameDl(self: *DebugInfo, address: usize) ?[]const u8 {
+ _ = self;
+
+ var ctx: struct {
+ // Input
+ address: usize,
+ // Output
+ name: []const u8 = "",
+ } = .{ .address = address };
+ const CtxTy = @TypeOf(ctx);
+
+ if (os.dl_iterate_phdr(&ctx, error{Found}, struct {
+ fn callback(info: *os.dl_phdr_info, size: usize, context: *CtxTy) !void {
+ _ = size;
+ if (context.address < info.dlpi_addr) return;
+ const phdrs = info.dlpi_phdr[0..info.dlpi_phnum];
+ for (phdrs) |*phdr| {
+ if (phdr.p_type != elf.PT_LOAD) continue;
+
+ const seg_start = info.dlpi_addr +% phdr.p_vaddr;
+ const seg_end = seg_start + phdr.p_memsz;
+ if (context.address >= seg_start and context.address < seg_end) {
+ context.name = mem.sliceTo(info.dlpi_name, 0) orelse "";
+ break;
+ }
+ } else return;
+
+ return error.Found;
+ }
+ }.callback)) {
+ return null;
+ } else |err| switch (err) {
+ error.Found => return fs.path.basename(ctx.name),
+ }
+
+ return null;
+ }
+
fn lookupModuleDl(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
var ctx: struct {
// Input
@@ -1359,6 +1821,8 @@ pub const DebugInfo = struct {
// Output
base_address: usize = undefined,
name: []const u8 = undefined,
+ build_id: ?[]const u8 = null,
+ gnu_eh_frame: ?[]const u8 = null,
} = .{ .address = address };
const CtxTy = @TypeOf(ctx);
@@ -1373,18 +1837,40 @@ pub const DebugInfo = struct {
for (phdrs) |*phdr| {
if (phdr.p_type != elf.PT_LOAD) continue;
- const seg_start = info.dlpi_addr + phdr.p_vaddr;
+ // Overflowing addition is used to handle the case of VSDOs having a p_vaddr = 0xffffffffff700000
+ const seg_start = info.dlpi_addr +% phdr.p_vaddr;
const seg_end = seg_start + phdr.p_memsz;
-
if (context.address >= seg_start and context.address < seg_end) {
// Android libc uses NULL instead of an empty string to mark the
// main program
context.name = mem.sliceTo(info.dlpi_name, 0) orelse "";
context.base_address = info.dlpi_addr;
- // Stop the iteration
- return error.Found;
+ break;
+ }
+ } else return;
+
+ for (info.dlpi_phdr[0..info.dlpi_phnum]) |phdr| {
+ switch (phdr.p_type) {
+ elf.PT_NOTE => {
+ // Look for .note.gnu.build-id
+ const note_bytes = @as([*]const u8, @ptrFromInt(info.dlpi_addr + phdr.p_vaddr))[0..phdr.p_memsz];
+ const name_size = mem.readIntSliceNative(u32, note_bytes[0..4]);
+ if (name_size != 4) continue;
+ const desc_size = mem.readIntSliceNative(u32, note_bytes[4..8]);
+ const note_type = mem.readIntSliceNative(u32, note_bytes[8..12]);
+ if (note_type != elf.NT_GNU_BUILD_ID) continue;
+ if (!mem.eql(u8, "GNU\x00", note_bytes[12..16])) continue;
+ context.build_id = note_bytes[16..][0..desc_size];
+ },
+ elf.PT_GNU_EH_FRAME => {
+ context.gnu_eh_frame = @as([*]const u8, @ptrFromInt(info.dlpi_addr + phdr.p_vaddr))[0..phdr.p_memsz];
+ },
+ else => {},
}
}
+
+ // Stop the iteration
+ return error.Found;
}
}.callback)) {
return error.MissingDebugInfo;
@@ -1399,20 +1885,24 @@ pub const DebugInfo = struct {
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
- // TODO https://github.com/ziglang/zig/issues/5525
- const copy = if (ctx.name.len > 0)
- fs.cwd().openFile(ctx.name, .{ .intended_io_mode = .blocking })
- else
- fs.openSelfExe(.{ .intended_io_mode = .blocking });
-
- const elf_file = copy catch |err| switch (err) {
- error.FileNotFound => return error.MissingDebugInfo,
- else => return err,
- };
+ var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
+ if (ctx.gnu_eh_frame) |eh_frame_hdr| {
+ // This is a special case - pointer offsets inside .eh_frame_hdr
+ // are encoded relative to its base address, so we must use the
+ // version that is already memory mapped, and not the one that
+ // will be mapped separately from the ELF file.
+ sections[@intFromEnum(DW.DwarfSection.eh_frame_hdr)] = .{
+ .data = eh_frame_hdr,
+ .owned = false,
+ };
+ }
- obj_di.* = try readElfDebugInfo(self.allocator, elf_file);
+ obj_di.* = try readElfDebugInfo(self.allocator, if (ctx.name.len > 0) ctx.name else null, ctx.build_id, null, §ions, null);
obj_di.base_address = ctx.base_address;
+ // Missing unwind info isn't treated as a failure, as the unwinder will fall back to FP-based unwinding
+ obj_di.dwarf.scanAllUnwindInfo(self.allocator, ctx.base_address) catch {};
+
try self.address_map.putNoClobber(ctx.base_address, obj_di);
return obj_di;
@@ -1434,11 +1924,16 @@ pub const DebugInfo = struct {
pub const ModuleDebugInfo = switch (native_os) {
.macos, .ios, .watchos, .tvos => struct {
base_address: usize,
+ vmaddr_slide: usize,
mapped_memory: []align(mem.page_size) const u8,
symbols: []const MachoSymbol,
strings: [:0]const u8,
ofiles: OFileTable,
+ // Backed by the in-memory sections mapped by the loader
+ unwind_info: ?[]const u8 = null,
+ eh_frame: ?[]const u8 = null,
+
const OFileTable = std.StringHashMap(OFileInfo);
const OFileInfo = struct {
di: DW.DwarfInfo,
@@ -1457,7 +1952,7 @@ pub const ModuleDebugInfo = switch (native_os) {
os.munmap(self.mapped_memory);
}
- fn loadOFile(self: *@This(), allocator: mem.Allocator, o_file_path: []const u8) !OFileInfo {
+ fn loadOFile(self: *@This(), allocator: mem.Allocator, o_file_path: []const u8) !*OFileInfo {
const o_file = try fs.cwd().openFile(o_file_path, .{ .intended_io_mode = .blocking });
const mapped_mem = try mapWholeFile(o_file);
@@ -1500,95 +1995,40 @@ pub const ModuleDebugInfo = switch (native_os) {
addr_table.putAssumeCapacityNoClobber(sym_name, sym.n_value);
}
- var opt_debug_line: ?macho.section_64 = null;
- var opt_debug_info: ?macho.section_64 = null;
- var opt_debug_abbrev: ?macho.section_64 = null;
- var opt_debug_str: ?macho.section_64 = null;
- var opt_debug_str_offsets: ?macho.section_64 = null;
- var opt_debug_line_str: ?macho.section_64 = null;
- var opt_debug_ranges: ?macho.section_64 = null;
- var opt_debug_loclists: ?macho.section_64 = null;
- var opt_debug_rnglists: ?macho.section_64 = null;
- var opt_debug_addr: ?macho.section_64 = null;
- var opt_debug_names: ?macho.section_64 = null;
- var opt_debug_frame: ?macho.section_64 = null;
+ var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
+ if (self.eh_frame) |eh_frame| sections[@intFromEnum(DW.DwarfSection.eh_frame)] = .{
+ .data = eh_frame,
+ .owned = false,
+ };
for (segcmd.?.getSections()) |sect| {
- const name = sect.sectName();
- if (mem.eql(u8, name, "__debug_line")) {
- opt_debug_line = sect;
- } else if (mem.eql(u8, name, "__debug_info")) {
- opt_debug_info = sect;
- } else if (mem.eql(u8, name, "__debug_abbrev")) {
- opt_debug_abbrev = sect;
- } else if (mem.eql(u8, name, "__debug_str")) {
- opt_debug_str = sect;
- } else if (mem.eql(u8, name, "__debug_str_offsets")) {
- opt_debug_str_offsets = sect;
- } else if (mem.eql(u8, name, "__debug_line_str")) {
- opt_debug_line_str = sect;
- } else if (mem.eql(u8, name, "__debug_ranges")) {
- opt_debug_ranges = sect;
- } else if (mem.eql(u8, name, "__debug_loclists")) {
- opt_debug_loclists = sect;
- } else if (mem.eql(u8, name, "__debug_rnglists")) {
- opt_debug_rnglists = sect;
- } else if (mem.eql(u8, name, "__debug_addr")) {
- opt_debug_addr = sect;
- } else if (mem.eql(u8, name, "__debug_names")) {
- opt_debug_names = sect;
- } else if (mem.eql(u8, name, "__debug_frame")) {
- opt_debug_frame = sect;
+ if (!std.mem.eql(u8, "__DWARF", sect.segName())) continue;
+
+ var section_index: ?usize = null;
+ inline for (@typeInfo(DW.DwarfSection).Enum.fields, 0..) |section, i| {
+ if (mem.eql(u8, "__" ++ section.name, sect.sectName())) section_index = i;
}
+ if (section_index == null) continue;
+
+ const section_bytes = try chopSlice(mapped_mem, sect.offset, sect.size);
+ sections[section_index.?] = .{
+ .data = section_bytes,
+ .virtual_address = sect.addr,
+ .owned = false,
+ };
}
- const debug_line = opt_debug_line orelse
- return error.MissingDebugInfo;
- const debug_info = opt_debug_info orelse
- return error.MissingDebugInfo;
- const debug_str = opt_debug_str orelse
- return error.MissingDebugInfo;
- const debug_abbrev = opt_debug_abbrev orelse
- return error.MissingDebugInfo;
+ const missing_debug_info =
+ sections[@intFromEnum(DW.DwarfSection.debug_info)] == null or
+ sections[@intFromEnum(DW.DwarfSection.debug_abbrev)] == null or
+ sections[@intFromEnum(DW.DwarfSection.debug_str)] == null or
+ sections[@intFromEnum(DW.DwarfSection.debug_line)] == null;
+ if (missing_debug_info) return error.MissingDebugInfo;
var di = DW.DwarfInfo{
.endian = .Little,
- .debug_info = try chopSlice(mapped_mem, debug_info.offset, debug_info.size),
- .debug_abbrev = try chopSlice(mapped_mem, debug_abbrev.offset, debug_abbrev.size),
- .debug_str = try chopSlice(mapped_mem, debug_str.offset, debug_str.size),
- .debug_str_offsets = if (opt_debug_str_offsets) |debug_str_offsets|
- try chopSlice(mapped_mem, debug_str_offsets.offset, debug_str_offsets.size)
- else
- null,
- .debug_line = try chopSlice(mapped_mem, debug_line.offset, debug_line.size),
- .debug_line_str = if (opt_debug_line_str) |debug_line_str|
- try chopSlice(mapped_mem, debug_line_str.offset, debug_line_str.size)
- else
- null,
- .debug_ranges = if (opt_debug_ranges) |debug_ranges|
- try chopSlice(mapped_mem, debug_ranges.offset, debug_ranges.size)
- else
- null,
- .debug_loclists = if (opt_debug_loclists) |debug_loclists|
- try chopSlice(mapped_mem, debug_loclists.offset, debug_loclists.size)
- else
- null,
- .debug_rnglists = if (opt_debug_rnglists) |debug_rnglists|
- try chopSlice(mapped_mem, debug_rnglists.offset, debug_rnglists.size)
- else
- null,
- .debug_addr = if (opt_debug_addr) |debug_addr|
- try chopSlice(mapped_mem, debug_addr.offset, debug_addr.size)
- else
- null,
- .debug_names = if (opt_debug_names) |debug_names|
- try chopSlice(mapped_mem, debug_names.offset, debug_names.size)
- else
- null,
- .debug_frame = if (opt_debug_frame) |debug_frame|
- try chopSlice(mapped_mem, debug_frame.offset, debug_frame.size)
- else
- null,
+ .sections = sections,
+ .is_macho = true,
};
try DW.openDwarfDebugInfo(&di, allocator);
@@ -1598,52 +2038,38 @@ pub const ModuleDebugInfo = switch (native_os) {
};
// Add the debug info to the cache
- try self.ofiles.putNoClobber(o_file_path, info);
+ const result = try self.ofiles.getOrPut(o_file_path);
+ assert(!result.found_existing);
+ result.value_ptr.* = info;
- return info;
+ return result.value_ptr;
}
pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
nosuspend {
- // Translate the VA into an address into this object
- const relocated_address = address - self.base_address;
-
- // Find the .o file where this symbol is defined
- const symbol = machoSearchSymbols(self.symbols, relocated_address) orelse
- return SymbolInfo{};
- const addr_off = relocated_address - symbol.addr;
+ const result = try self.getOFileInfoForAddress(allocator, address);
+ if (result.symbol == null) return .{};
// Take the symbol name from the N_FUN STAB entry, we're going to
// use it if we fail to find the DWARF infos
- const stab_symbol = mem.sliceTo(self.strings[symbol.strx..], 0);
- const o_file_path = mem.sliceTo(self.strings[symbol.ofile..], 0);
-
- // Check if its debug infos are already in the cache
- var o_file_info = self.ofiles.get(o_file_path) orelse
- (self.loadOFile(allocator, o_file_path) catch |err| switch (err) {
- error.FileNotFound,
- error.MissingDebugInfo,
- error.InvalidDebugInfo,
- => {
- return SymbolInfo{ .symbol_name = stab_symbol };
- },
- else => return err,
- });
- const o_file_di = &o_file_info.di;
+ const stab_symbol = mem.sliceTo(self.strings[result.symbol.?.strx..], 0);
+ if (result.o_file_info == null) return .{ .symbol_name = stab_symbol };
// Translate again the address, this time into an address inside the
// .o file
- const relocated_address_o = o_file_info.addr_table.get(stab_symbol) orelse return SymbolInfo{
+ const relocated_address_o = result.o_file_info.?.addr_table.get(stab_symbol) orelse return .{
.symbol_name = "???",
};
+ const addr_off = result.relocated_address - result.symbol.?.addr;
+ const o_file_di = &result.o_file_info.?.di;
if (o_file_di.findCompileUnit(relocated_address_o)) |compile_unit| {
return SymbolInfo{
.symbol_name = o_file_di.getSymbolName(relocated_address_o) orelse "???",
.compile_unit_name = compile_unit.die.getAttrString(
o_file_di,
DW.AT.name,
- o_file_di.debug_str,
+ o_file_di.section(.debug_str),
compile_unit.*,
) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => "???",
@@ -1663,39 +2089,61 @@ pub const ModuleDebugInfo = switch (native_os) {
},
else => return err,
}
+ }
+ }
+
+ pub fn getOFileInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !struct {
+ relocated_address: usize,
+ symbol: ?*const MachoSymbol = null,
+ o_file_info: ?*OFileInfo = null,
+ } {
+ nosuspend {
+ // Translate the VA into an address into this object
+ const relocated_address = address - self.vmaddr_slide;
+
+ // Find the .o file where this symbol is defined
+ const symbol = machoSearchSymbols(self.symbols, relocated_address) orelse return .{
+ .relocated_address = relocated_address,
+ };
+
+ // Check if its debug infos are already in the cache
+ const o_file_path = mem.sliceTo(self.strings[symbol.ofile..], 0);
+ var o_file_info = self.ofiles.getPtr(o_file_path) orelse
+ (self.loadOFile(allocator, o_file_path) catch |err| switch (err) {
+ error.FileNotFound,
+ error.MissingDebugInfo,
+ error.InvalidDebugInfo,
+ => return .{
+ .relocated_address = relocated_address,
+ .symbol = symbol,
+ },
+ else => return err,
+ });
- unreachable;
+ return .{
+ .relocated_address = relocated_address,
+ .symbol = symbol,
+ .o_file_info = o_file_info,
+ };
}
}
+
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ return if ((try self.getOFileInfoForAddress(allocator, address)).o_file_info) |o_file_info| &o_file_info.di else null;
+ }
},
.uefi, .windows => struct {
base_address: usize,
debug_data: PdbOrDwarf,
coff_image_base: u64,
+ /// Only used if debug_data is .pdb
coff_section_headers: []coff.SectionHeader,
fn deinit(self: *@This(), allocator: mem.Allocator) void {
- switch (self.debug_data) {
- .dwarf => |*dwarf| {
- allocator.free(dwarf.debug_info);
- allocator.free(dwarf.debug_abbrev);
- allocator.free(dwarf.debug_str);
- allocator.free(dwarf.debug_line);
- if (dwarf.debug_str_offsets) |d| allocator.free(d);
- if (dwarf.debug_line_str) |d| allocator.free(d);
- if (dwarf.debug_ranges) |d| allocator.free(d);
- if (dwarf.debug_loclists) |d| allocator.free(d);
- if (dwarf.debug_rnglists) |d| allocator.free(d);
- if (dwarf.debug_addr) |d| allocator.free(d);
- if (dwarf.debug_names) |d| allocator.free(d);
- if (dwarf.debug_frame) |d| allocator.free(d);
- },
- .pdb => {
- allocator.free(self.coff_section_headers);
- },
- }
-
self.debug_data.deinit(allocator);
+ if (self.debug_data == .pdb) {
+ allocator.free(self.coff_section_headers);
+ }
}
pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
@@ -1747,15 +2195,27 @@ pub const ModuleDebugInfo = switch (native_os) {
.line_info = opt_line_info,
};
}
+
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ _ = allocator;
+ _ = address;
+
+ return switch (self.debug_data) {
+ .dwarf => |*dwarf| dwarf,
+ else => null,
+ };
+ }
},
.linux, .netbsd, .freebsd, .dragonfly, .openbsd, .haiku, .solaris => struct {
base_address: usize,
dwarf: DW.DwarfInfo,
mapped_memory: []align(mem.page_size) const u8,
+ external_mapped_memory: ?[]align(mem.page_size) const u8,
fn deinit(self: *@This(), allocator: mem.Allocator) void {
self.dwarf.deinit(allocator);
os.munmap(self.mapped_memory);
+ if (self.external_mapped_memory) |m| os.munmap(m);
}
pub fn getSymbolAtAddress(self: *@This(), allocator: mem.Allocator, address: usize) !SymbolInfo {
@@ -1763,6 +2223,12 @@ pub const ModuleDebugInfo = switch (native_os) {
const relocated_address = address - self.base_address;
return getSymbolFromDwarf(allocator, relocated_address, &self.dwarf);
}
+
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ _ = allocator;
+ _ = address;
+ return &self.dwarf;
+ }
},
.wasi => struct {
fn deinit(self: *@This(), allocator: mem.Allocator) void {
@@ -1776,6 +2242,13 @@ pub const ModuleDebugInfo = switch (native_os) {
_ = address;
return SymbolInfo{};
}
+
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ _ = self;
+ _ = allocator;
+ _ = address;
+ return null;
+ }
},
else => DW.DwarfInfo,
};
@@ -1784,7 +2257,7 @@ fn getSymbolFromDwarf(allocator: mem.Allocator, address: u64, di: *DW.DwarfInfo)
if (nosuspend di.findCompileUnit(address)) |compile_unit| {
return SymbolInfo{
.symbol_name = nosuspend di.getSymbolName(address) orelse "???",
- .compile_unit_name = compile_unit.die.getAttrString(di, DW.AT.name, di.debug_str, compile_unit.*) catch |err| switch (err) {
+ .compile_unit_name = compile_unit.die.getAttrString(di, DW.AT.name, di.section(.debug_str), compile_unit.*) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => "???",
},
.line_info = nosuspend di.getLineNumberInfo(allocator, compile_unit.*, address) catch |err| switch (err) {
@@ -1932,52 +2405,13 @@ fn dumpSegfaultInfoPosix(sig: i32, addr: usize, ctx_ptr: ?*const anyopaque) void
} catch os.abort();
switch (native_arch) {
- .x86 => {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = @as(usize, @intCast(ctx.mcontext.gregs[os.REG.EIP]));
- const bp = @as(usize, @intCast(ctx.mcontext.gregs[os.REG.EBP]));
- dumpStackTraceFromBase(bp, ip);
- },
- .x86_64 => {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = switch (native_os) {
- .linux, .netbsd, .solaris => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.RIP])),
- .freebsd => @as(usize, @intCast(ctx.mcontext.rip)),
- .openbsd => @as(usize, @intCast(ctx.sc_rip)),
- .macos => @as(usize, @intCast(ctx.mcontext.ss.rip)),
- else => unreachable,
- };
- const bp = switch (native_os) {
- .linux, .netbsd, .solaris => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.RBP])),
- .openbsd => @as(usize, @intCast(ctx.sc_rbp)),
- .freebsd => @as(usize, @intCast(ctx.mcontext.rbp)),
- .macos => @as(usize, @intCast(ctx.mcontext.ss.rbp)),
- else => unreachable,
- };
- dumpStackTraceFromBase(bp, ip);
- },
- .arm => {
+ .x86,
+ .x86_64,
+ .arm,
+ .aarch64,
+ => {
const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = @as(usize, @intCast(ctx.mcontext.arm_pc));
- const bp = @as(usize, @intCast(ctx.mcontext.arm_fp));
- dumpStackTraceFromBase(bp, ip);
- },
- .aarch64 => {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = switch (native_os) {
- .macos => @as(usize, @intCast(ctx.mcontext.ss.pc)),
- .netbsd => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.PC])),
- .freebsd => @as(usize, @intCast(ctx.mcontext.gpregs.elr)),
- else => @as(usize, @intCast(ctx.mcontext.pc)),
- };
- // x29 is the ABI-designated frame pointer
- const bp = switch (native_os) {
- .macos => @as(usize, @intCast(ctx.mcontext.ss.fp)),
- .netbsd => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.FP])),
- .freebsd => @as(usize, @intCast(ctx.mcontext.gpregs.x[os.REG.FP])),
- else => @as(usize, @intCast(ctx.mcontext.regs[29])),
- };
- dumpStackTraceFromBase(bp, ip);
+ dumpStackTraceFromBase(ctx);
},
else => {},
}
@@ -2036,16 +2470,15 @@ fn handleSegfaultWindowsExtra(
}
fn dumpSegfaultInfoWindows(info: *windows.EXCEPTION_POINTERS, msg: u8, label: ?[]const u8) void {
- const regs = info.ContextRecord.getRegs();
const stderr = io.getStdErr().writer();
_ = switch (msg) {
0 => stderr.print("{s}\n", .{label.?}),
1 => stderr.print("Segmentation fault at address 0x{x}\n", .{info.ExceptionRecord.ExceptionInformation[1]}),
- 2 => stderr.print("Illegal instruction at address 0x{x}\n", .{regs.ip}),
+ 2 => stderr.print("Illegal instruction at address 0x{x}\n", .{info.ContextRecord.getRegs().ip}),
else => unreachable,
} catch os.abort();
- dumpStackTraceFromBase(regs.bp, regs.ip);
+ dumpStackTraceFromBase(info.ContextRecord);
}
pub fn dumpStackPointerAddr(prefix: []const u8) void {
diff --git a/lib/std/dwarf.zig b/lib/std/dwarf.zig
@@ -3,9 +3,11 @@ const std = @import("std.zig");
const debug = std.debug;
const fs = std.fs;
const io = std.io;
+const os = std.os;
const mem = std.mem;
const math = std.math;
const leb = @import("leb128.zig");
+const assert = std.debug.assert;
pub const TAG = @import("dwarf/TAG.zig");
pub const AT = @import("dwarf/AT.zig");
@@ -13,6 +15,10 @@ pub const OP = @import("dwarf/OP.zig");
pub const LANG = @import("dwarf/LANG.zig");
pub const FORM = @import("dwarf/FORM.zig");
pub const ATE = @import("dwarf/ATE.zig");
+pub const EH = @import("dwarf/EH.zig");
+pub const abi = @import("dwarf/abi.zig");
+pub const call_frame = @import("dwarf/call_frame.zig");
+pub const expressions = @import("dwarf/expressions.zig");
pub const LLE = struct {
pub const end_of_list = 0x00;
@@ -140,11 +146,11 @@ pub const CC = enum(u8) {
pass_by_reference = 0x4,
pass_by_value = 0x5,
- lo_user = 0x40,
- hi_user = 0xff,
-
GNU_renesas_sh = 0x40,
GNU_borland_fastcall_i386 = 0x41,
+
+ pub const lo_user = 0x40;
+ pub const hi_user = 0xff;
};
pub const Format = enum { @"32", @"64" };
@@ -157,15 +163,9 @@ const PcRange = struct {
const Func = struct {
pc_range: ?PcRange,
name: ?[]const u8,
-
- fn deinit(func: *Func, allocator: mem.Allocator) void {
- if (func.name) |name| {
- allocator.free(name);
- }
- }
};
-const CompileUnit = struct {
+pub const CompileUnit = struct {
version: u16,
is_64: bool,
die: *Die,
@@ -175,6 +175,7 @@ const CompileUnit = struct {
addr_base: usize,
rnglists_base: usize,
loclists_base: usize,
+ frame_base: ?*const FormValue,
};
const AbbrevTable = std.ArrayList(AbbrevTableEntry);
@@ -210,7 +211,7 @@ const AbbrevAttr = struct {
payload: i64,
};
-const FormValue = union(enum) {
+pub const FormValue = union(enum) {
Address: u64,
AddrOffset: usize,
Block: []u8,
@@ -292,7 +293,7 @@ const Die = struct {
fn getAttrAddr(
self: *const Die,
- di: *DwarfInfo,
+ di: *const DwarfInfo,
id: u64,
compile_unit: CompileUnit,
) error{ InvalidDebugInfo, MissingDebugInfo }!u64 {
@@ -337,7 +338,7 @@ const Die = struct {
FormValue.String => |value| return value,
FormValue.StrPtr => |offset| return di.getString(offset),
FormValue.StrOffset => |index| {
- const debug_str_offsets = di.debug_str_offsets orelse return badDwarf();
+ const debug_str_offsets = di.section(.debug_str_offsets) orelse return badDwarf();
if (compile_unit.str_offsets_base == 0) return badDwarf();
if (compile_unit.is_64) {
const byte_offset = compile_unit.str_offsets_base + 8 * index;
@@ -642,27 +643,75 @@ fn getAbbrevTableEntry(abbrev_table: *const AbbrevTable, abbrev_code: u64) ?*con
return null;
}
+pub const DwarfSection = enum {
+ debug_info,
+ debug_abbrev,
+ debug_str,
+ debug_str_offsets,
+ debug_line,
+ debug_line_str,
+ debug_ranges,
+ debug_loclists,
+ debug_rnglists,
+ debug_addr,
+ debug_names,
+ debug_frame,
+ eh_frame,
+ eh_frame_hdr,
+};
+
pub const DwarfInfo = struct {
+ pub const Section = struct {
+ data: []const u8,
+ // Module-relative virtual address.
+ // Only set if the section data was loaded from disk.
+ virtual_address: ?usize = null,
+ // If `data` is owned by this DwarfInfo.
+ owned: bool,
+
+ // For sections that are not memory mapped by the loader, this is an offset
+ // from `data.ptr` to where the section would have been mapped. Otherwise,
+ // `data` is directly backed by the section and the offset is zero.
+ pub fn virtualOffset(self: Section, base_address: usize) i64 {
+ return if (self.virtual_address) |va|
+ @as(i64, @intCast(base_address + va)) -
+ @as(i64, @intCast(@intFromPtr(self.data.ptr)))
+ else
+ 0;
+ }
+ };
+
+ const num_sections = std.enums.directEnumArrayLen(DwarfSection, 0);
+ pub const SectionArray = [num_sections]?Section;
+ pub const null_section_array = [_]?Section{null} ** num_sections;
+
endian: std.builtin.Endian,
- // No memory is owned by the DwarfInfo
- debug_info: []const u8,
- debug_abbrev: []const u8,
- debug_str: []const u8,
- debug_str_offsets: ?[]const u8,
- debug_line: []const u8,
- debug_line_str: ?[]const u8,
- debug_ranges: ?[]const u8,
- debug_loclists: ?[]const u8,
- debug_rnglists: ?[]const u8,
- debug_addr: ?[]const u8,
- debug_names: ?[]const u8,
- debug_frame: ?[]const u8,
+ sections: SectionArray = null_section_array,
+ is_macho: bool,
+
// Filled later by the initializer
abbrev_table_list: std.ArrayListUnmanaged(AbbrevTableHeader) = .{},
compile_unit_list: std.ArrayListUnmanaged(CompileUnit) = .{},
func_list: std.ArrayListUnmanaged(Func) = .{},
+ eh_frame_hdr: ?ExceptionFrameHeader = null,
+ // These lookup tables are only used if `eh_frame_hdr` is null
+ cie_map: std.AutoArrayHashMapUnmanaged(u64, CommonInformationEntry) = .{},
+ // Sorted by start_pc
+ fde_list: std.ArrayListUnmanaged(FrameDescriptionEntry) = .{},
+
+ pub fn section(di: DwarfInfo, dwarf_section: DwarfSection) ?[]const u8 {
+ return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.data else null;
+ }
+
+ pub fn sectionVirtualOffset(di: DwarfInfo, dwarf_section: DwarfSection, base_address: usize) ?i64 {
+ return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.virtualOffset(base_address) else null;
+ }
+
pub fn deinit(di: *DwarfInfo, allocator: mem.Allocator) void {
+ for (di.sections) |opt_section| {
+ if (opt_section) |s| if (s.owned) allocator.free(s.data);
+ }
for (di.abbrev_table_list.items) |*abbrev| {
abbrev.deinit();
}
@@ -672,10 +721,9 @@ pub const DwarfInfo = struct {
allocator.destroy(cu.die);
}
di.compile_unit_list.deinit(allocator);
- for (di.func_list.items) |*func| {
- func.deinit(allocator);
- }
di.func_list.deinit(allocator);
+ di.cie_map.deinit(allocator);
+ di.fde_list.deinit(allocator);
}
pub fn getSymbolName(di: *DwarfInfo, address: u64) ?[]const u8 {
@@ -691,7 +739,7 @@ pub const DwarfInfo = struct {
}
fn scanAllFunctions(di: *DwarfInfo, allocator: mem.Allocator) !void {
- var stream = io.fixedBufferStream(di.debug_info);
+ var stream = io.fixedBufferStream(di.section(.debug_info).?);
const in = stream.reader();
const seekable = &stream.seekableStream();
var this_unit_offset: u64 = 0;
@@ -755,6 +803,7 @@ pub const DwarfInfo = struct {
.addr_base = if (die_obj.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0,
.rnglists_base = if (die_obj.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0,
.loclists_base = if (die_obj.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0,
+ .frame_base = die_obj.getAttr(AT.frame_base),
};
},
TAG.subprogram, TAG.inlined_subroutine, TAG.subroutine, TAG.entry_point => {
@@ -764,8 +813,7 @@ pub const DwarfInfo = struct {
// Prevent endless loops
while (depth > 0) : (depth -= 1) {
if (this_die_obj.getAttr(AT.name)) |_| {
- const name = try this_die_obj.getAttrString(di, AT.name, di.debug_str, compile_unit);
- break :x try allocator.dupe(u8, name);
+ break :x try this_die_obj.getAttrString(di, AT.name, di.section(.debug_str), compile_unit);
} else if (this_die_obj.getAttr(AT.abstract_origin)) |_| {
// Follow the DIE it points to and repeat
const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin);
@@ -796,34 +844,58 @@ pub const DwarfInfo = struct {
break :x null;
};
- const pc_range = x: {
- if (die_obj.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| {
- if (die_obj.getAttr(AT.high_pc)) |high_pc_value| {
- const pc_end = switch (high_pc_value.*) {
- FormValue.Address => |value| value,
- FormValue.Const => |value| b: {
- const offset = try value.asUnsignedLe();
- break :b (low_pc + offset);
- },
- else => return badDwarf(),
- };
- break :x PcRange{
+ var range_added = if (die_obj.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| blk: {
+ if (die_obj.getAttr(AT.high_pc)) |high_pc_value| {
+ const pc_end = switch (high_pc_value.*) {
+ FormValue.Address => |value| value,
+ FormValue.Const => |value| b: {
+ const offset = try value.asUnsignedLe();
+ break :b (low_pc + offset);
+ },
+ else => return badDwarf(),
+ };
+
+ try di.func_list.append(allocator, Func{
+ .name = fn_name,
+ .pc_range = .{
.start = low_pc,
.end = pc_end,
- };
- } else {
- break :x null;
- }
- } else |err| {
- if (err != error.MissingDebugInfo) return err;
- break :x null;
+ },
+ });
+
+ break :blk true;
}
+
+ break :blk false;
+ } else |err| blk: {
+ if (err != error.MissingDebugInfo) return err;
+ break :blk false;
};
- try di.func_list.append(allocator, Func{
- .name = fn_name,
- .pc_range = pc_range,
- });
+ if (die_obj.getAttr(AT.ranges)) |ranges_value| blk: {
+ var iter = DebugRangeIterator.init(ranges_value, di, &compile_unit) catch |err| {
+ if (err != error.MissingDebugInfo) return err;
+ break :blk;
+ };
+
+ while (try iter.next()) |range| {
+ range_added = true;
+ try di.func_list.append(allocator, Func{
+ .name = fn_name,
+ .pc_range = .{
+ .start = range.start_addr,
+ .end = range.end_addr,
+ },
+ });
+ }
+ }
+
+ if (fn_name != null and !range_added) {
+ try di.func_list.append(allocator, Func{
+ .name = fn_name,
+ .pc_range = null,
+ });
+ }
},
else => {},
}
@@ -836,7 +908,7 @@ pub const DwarfInfo = struct {
}
fn scanAllCompileUnits(di: *DwarfInfo, allocator: mem.Allocator) !void {
- var stream = io.fixedBufferStream(di.debug_info);
+ var stream = io.fixedBufferStream(di.section(.debug_info).?);
const in = &stream.reader();
const seekable = &stream.seekableStream();
var this_unit_offset: u64 = 0;
@@ -892,6 +964,7 @@ pub const DwarfInfo = struct {
.addr_base = if (compile_unit_die.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0,
.rnglists_base = if (compile_unit_die.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0,
.loclists_base = if (compile_unit_die.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0,
+ .frame_base = compile_unit_die.getAttr(AT.frame_base),
};
compile_unit.pc_range = x: {
@@ -924,17 +997,18 @@ pub const DwarfInfo = struct {
}
}
- pub fn findCompileUnit(di: *DwarfInfo, target_address: u64) !*const CompileUnit {
- for (di.compile_unit_list.items) |*compile_unit| {
- if (compile_unit.pc_range) |range| {
- if (target_address >= range.start and target_address < range.end) return compile_unit;
- }
+ const DebugRangeIterator = struct {
+ base_address: u64,
+ section_type: DwarfSection,
+ di: *const DwarfInfo,
+ compile_unit: *const CompileUnit,
+ stream: io.FixedBufferStream([]const u8),
- const opt_debug_ranges = if (compile_unit.version >= 5) di.debug_rnglists else di.debug_ranges;
- const debug_ranges = opt_debug_ranges orelse continue;
+ pub fn init(ranges_value: *const FormValue, di: *const DwarfInfo, compile_unit: *const CompileUnit) !@This() {
+ const section_type = if (compile_unit.version >= 5) DwarfSection.debug_rnglists else DwarfSection.debug_ranges;
+ const debug_ranges = di.section(section_type) orelse return error.MissingDebugInfo;
- const ranges_val = compile_unit.die.getAttr(AT.ranges) orelse continue;
- const ranges_offset = switch (ranges_val.*) {
+ const ranges_offset = switch (ranges_value.*) {
.SecOffset => |off| off,
.Const => |c| try c.asUnsignedLe(),
.RangeListOffset => |idx| off: {
@@ -954,8 +1028,7 @@ pub const DwarfInfo = struct {
};
var stream = io.fixedBufferStream(debug_ranges);
- const in = &stream.reader();
- const seekable = &stream.seekableStream();
+ try stream.seekTo(ranges_offset);
// All the addresses in the list are relative to the value
// specified by DW_AT.low_pc or to some other value encoded
@@ -966,86 +1039,122 @@ pub const DwarfInfo = struct {
else => return err,
};
- try seekable.seekTo(ranges_offset);
+ return .{
+ .base_address = base_address,
+ .section_type = section_type,
+ .di = di,
+ .compile_unit = compile_unit,
+ .stream = stream,
+ };
+ }
- if (compile_unit.version >= 5) {
- while (true) {
+ // Returns the next range in the list, or null if the end was reached.
+ pub fn next(self: *@This()) !?struct { start_addr: u64, end_addr: u64 } {
+ const in = self.stream.reader();
+ switch (self.section_type) {
+ .debug_rnglists => {
const kind = try in.readByte();
switch (kind) {
- RLE.end_of_list => break,
+ RLE.end_of_list => return null,
RLE.base_addressx => {
const index = try leb.readULEB128(usize, in);
- base_address = try di.readDebugAddr(compile_unit.*, index);
+ self.base_address = try self.di.readDebugAddr(self.compile_unit.*, index);
+ return try self.next();
},
RLE.startx_endx => {
const start_index = try leb.readULEB128(usize, in);
- const start_addr = try di.readDebugAddr(compile_unit.*, start_index);
+ const start_addr = try self.di.readDebugAddr(self.compile_unit.*, start_index);
const end_index = try leb.readULEB128(usize, in);
- const end_addr = try di.readDebugAddr(compile_unit.*, end_index);
+ const end_addr = try self.di.readDebugAddr(self.compile_unit.*, end_index);
- if (target_address >= start_addr and target_address < end_addr) {
- return compile_unit;
- }
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
},
RLE.startx_length => {
const start_index = try leb.readULEB128(usize, in);
- const start_addr = try di.readDebugAddr(compile_unit.*, start_index);
+ const start_addr = try self.di.readDebugAddr(self.compile_unit.*, start_index);
const len = try leb.readULEB128(usize, in);
const end_addr = start_addr + len;
- if (target_address >= start_addr and target_address < end_addr) {
- return compile_unit;
- }
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
},
RLE.offset_pair => {
const start_addr = try leb.readULEB128(usize, in);
const end_addr = try leb.readULEB128(usize, in);
+
// This is the only kind that uses the base address
- if (target_address >= base_address + start_addr and target_address < base_address + end_addr) {
- return compile_unit;
- }
+ return .{
+ .start_addr = self.base_address + start_addr,
+ .end_addr = self.base_address + end_addr,
+ };
},
RLE.base_address => {
- base_address = try in.readInt(usize, di.endian);
+ self.base_address = try in.readInt(usize, self.di.endian);
+ return try self.next();
},
RLE.start_end => {
- const start_addr = try in.readInt(usize, di.endian);
- const end_addr = try in.readInt(usize, di.endian);
- if (target_address >= start_addr and target_address < end_addr) {
- return compile_unit;
- }
+ const start_addr = try in.readInt(usize, self.di.endian);
+ const end_addr = try in.readInt(usize, self.di.endian);
+
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
},
RLE.start_length => {
- const start_addr = try in.readInt(usize, di.endian);
+ const start_addr = try in.readInt(usize, self.di.endian);
const len = try leb.readULEB128(usize, in);
const end_addr = start_addr + len;
- if (target_address >= start_addr and target_address < end_addr) {
- return compile_unit;
- }
+
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
},
else => return badDwarf(),
}
- }
- } else {
- while (true) {
- const begin_addr = try in.readInt(usize, di.endian);
- const end_addr = try in.readInt(usize, di.endian);
- if (begin_addr == 0 and end_addr == 0) {
- break;
- }
+ },
+ .debug_ranges => {
+ const start_addr = try in.readInt(usize, self.di.endian);
+ const end_addr = try in.readInt(usize, self.di.endian);
+ if (start_addr == 0 and end_addr == 0) return null;
+
// This entry selects a new value for the base address
- if (begin_addr == math.maxInt(usize)) {
- base_address = end_addr;
- continue;
+ if (start_addr == math.maxInt(usize)) {
+ self.base_address = end_addr;
+ return try self.next();
}
- if (target_address >= base_address + begin_addr and target_address < base_address + end_addr) {
- return compile_unit;
- }
- }
+
+ return .{
+ .start_addr = self.base_address + start_addr,
+ .end_addr = self.base_address + end_addr,
+ };
+ },
+ else => unreachable,
}
}
+ };
+
+ pub fn findCompileUnit(di: *const DwarfInfo, target_address: u64) !*const CompileUnit {
+ for (di.compile_unit_list.items) |*compile_unit| {
+ if (compile_unit.pc_range) |range| {
+ if (target_address >= range.start and target_address < range.end) return compile_unit;
+ }
+
+ const ranges_value = compile_unit.die.getAttr(AT.ranges) orelse continue;
+ var iter = DebugRangeIterator.init(ranges_value, di, compile_unit) catch continue;
+ while (try iter.next()) |range| {
+ if (target_address >= range.start_addr and target_address < range.end_addr) return compile_unit;
+ }
+ }
+
return missingDwarf();
}
@@ -1065,7 +1174,7 @@ pub const DwarfInfo = struct {
}
fn parseAbbrevTable(di: *DwarfInfo, allocator: mem.Allocator, offset: u64) !AbbrevTable {
- var stream = io.fixedBufferStream(di.debug_abbrev);
+ var stream = io.fixedBufferStream(di.section(.debug_abbrev).?);
const in = &stream.reader();
const seekable = &stream.seekableStream();
@@ -1146,11 +1255,11 @@ pub const DwarfInfo = struct {
compile_unit: CompileUnit,
target_address: u64,
) !debug.LineInfo {
- var stream = io.fixedBufferStream(di.debug_line);
+ var stream = io.fixedBufferStream(di.section(.debug_line).?);
const in = &stream.reader();
const seekable = &stream.seekableStream();
- const compile_unit_cwd = try compile_unit.die.getAttrString(di, AT.comp_dir, di.debug_line_str, compile_unit);
+ const compile_unit_cwd = try compile_unit.die.getAttrString(di, AT.comp_dir, di.section(.debug_line_str), compile_unit);
const line_info_offset = try compile_unit.die.getAttrSecOffset(AT.stmt_list);
try seekable.seekTo(line_info_offset);
@@ -1416,15 +1525,15 @@ pub const DwarfInfo = struct {
}
fn getString(di: DwarfInfo, offset: u64) ![]const u8 {
- return getStringGeneric(di.debug_str, offset);
+ return getStringGeneric(di.section(.debug_str), offset);
}
fn getLineString(di: DwarfInfo, offset: u64) ![]const u8 {
- return getStringGeneric(di.debug_line_str, offset);
+ return getStringGeneric(di.section(.debug_line_str), offset);
}
fn readDebugAddr(di: DwarfInfo, compile_unit: CompileUnit, index: u64) !u64 {
- const debug_addr = di.debug_addr orelse return badDwarf();
+ const debug_addr = di.section(.debug_addr) orelse return badDwarf();
// addr_base points to the first item after the header, however we
// need to read the header to know the size of each item. Empirically,
@@ -1448,10 +1557,689 @@ pub const DwarfInfo = struct {
else => badDwarf(),
};
}
+
+ /// If .eh_frame_hdr is present, then only the header needs to be parsed.
+ ///
+ /// Otherwise, .eh_frame and .debug_frame are scanned and a sorted list
+ /// of FDEs is built for binary searching during unwinding.
+ pub fn scanAllUnwindInfo(di: *DwarfInfo, allocator: mem.Allocator, base_address: usize) !void {
+ if (di.section(.eh_frame_hdr)) |eh_frame_hdr| blk: {
+ var stream = io.fixedBufferStream(eh_frame_hdr);
+ const reader = stream.reader();
+
+ const version = try reader.readByte();
+ if (version != 1) break :blk;
+
+ const eh_frame_ptr_enc = try reader.readByte();
+ if (eh_frame_ptr_enc == EH.PE.omit) break :blk;
+ const fde_count_enc = try reader.readByte();
+ if (fde_count_enc == EH.PE.omit) break :blk;
+ const table_enc = try reader.readByte();
+ if (table_enc == EH.PE.omit) break :blk;
+
+ const eh_frame_ptr = std.math.cast(usize, try readEhPointer(reader, eh_frame_ptr_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&eh_frame_hdr[stream.pos]),
+ .follow_indirect = true,
+ }, builtin.cpu.arch.endian()) orelse return badDwarf()) orelse return badDwarf();
+
+ const fde_count = std.math.cast(usize, try readEhPointer(reader, fde_count_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&eh_frame_hdr[stream.pos]),
+ .follow_indirect = true,
+ }, builtin.cpu.arch.endian()) orelse return badDwarf()) orelse return badDwarf();
+
+ const entry_size = try ExceptionFrameHeader.entrySize(table_enc);
+ const entries_len = fde_count * entry_size;
+ if (entries_len > eh_frame_hdr.len - stream.pos) return badDwarf();
+
+ di.eh_frame_hdr = .{
+ .eh_frame_ptr = eh_frame_ptr,
+ .table_enc = table_enc,
+ .fde_count = fde_count,
+ .entries = eh_frame_hdr[stream.pos..][0..entries_len],
+ };
+
+ // No need to scan .eh_frame, we have a binary search table already
+ return;
+ }
+
+ const frame_sections = [2]DwarfSection{ .eh_frame, .debug_frame };
+ for (frame_sections) |frame_section| {
+ if (di.section(frame_section)) |section_data| {
+ var stream = io.fixedBufferStream(section_data);
+ while (stream.pos < stream.buffer.len) {
+ const entry_header = try EntryHeader.read(&stream, frame_section, di.endian);
+ switch (entry_header.type) {
+ .cie => {
+ const cie = try CommonInformationEntry.parse(
+ entry_header.entry_bytes,
+ di.sectionVirtualOffset(frame_section, base_address).?,
+ true,
+ entry_header.is_64,
+ frame_section,
+ entry_header.length_offset,
+ @sizeOf(usize),
+ di.endian,
+ );
+ try di.cie_map.put(allocator, entry_header.length_offset, cie);
+ },
+ .fde => |cie_offset| {
+ const cie = di.cie_map.get(cie_offset) orelse return badDwarf();
+ const fde = try FrameDescriptionEntry.parse(
+ entry_header.entry_bytes,
+ di.sectionVirtualOffset(frame_section, base_address).?,
+ true,
+ cie,
+ @sizeOf(usize),
+ di.endian,
+ );
+ try di.fde_list.append(allocator, fde);
+ },
+ .terminator => break,
+ }
+ }
+
+ std.mem.sort(FrameDescriptionEntry, di.fde_list.items, {}, struct {
+ fn lessThan(ctx: void, a: FrameDescriptionEntry, b: FrameDescriptionEntry) bool {
+ _ = ctx;
+ return a.pc_begin < b.pc_begin;
+ }
+ }.lessThan);
+ }
+ }
+ }
+
+ /// Unwind a stack frame using DWARF unwinding info, updating the register context.
+ ///
+ /// If `.eh_frame_hdr` is available, it will be used to binary search for the FDE.
+ /// Otherwise, a linear scan of `.eh_frame` and `.debug_frame` is done to find the FDE.
+ ///
+ /// `explicit_fde_offset` is for cases where the FDE offset is known, such as when __unwind_info
+ /// defers unwinding to DWARF. This is an offset into the `.eh_frame` section.
+ pub fn unwindFrame(di: *const DwarfInfo, context: *UnwindContext, explicit_fde_offset: ?usize) !usize {
+ if (!comptime abi.isSupportedArch(builtin.target.cpu.arch)) return error.UnsupportedCpuArchitecture;
+ if (context.pc == 0) return 0;
+
+ // Find the FDE and CIE
+ var cie: CommonInformationEntry = undefined;
+ var fde: FrameDescriptionEntry = undefined;
+
+ if (explicit_fde_offset) |fde_offset| {
+ const dwarf_section: DwarfSection = .eh_frame;
+ const frame_section = di.section(dwarf_section) orelse return error.MissingFDE;
+ if (fde_offset >= frame_section.len) return error.MissingFDE;
+
+ var stream = io.fixedBufferStream(frame_section);
+ try stream.seekTo(fde_offset);
+
+ const fde_entry_header = try EntryHeader.read(&stream, dwarf_section, di.endian);
+ if (fde_entry_header.type != .fde) return error.MissingFDE;
+
+ const cie_offset = fde_entry_header.type.fde;
+ try stream.seekTo(cie_offset);
+
+ const cie_entry_header = try EntryHeader.read(&stream, dwarf_section, builtin.cpu.arch.endian());
+ if (cie_entry_header.type != .cie) return badDwarf();
+
+ cie = try CommonInformationEntry.parse(
+ cie_entry_header.entry_bytes,
+ 0,
+ true,
+ cie_entry_header.is_64,
+ dwarf_section,
+ cie_entry_header.length_offset,
+ @sizeOf(usize),
+ builtin.cpu.arch.endian(),
+ );
+
+ fde = try FrameDescriptionEntry.parse(
+ fde_entry_header.entry_bytes,
+ 0,
+ true,
+ cie,
+ @sizeOf(usize),
+ builtin.cpu.arch.endian(),
+ );
+ } else if (di.eh_frame_hdr) |header| {
+ const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
+ try header.findEntry(
+ context.isValidMemory,
+ eh_frame_len,
+ @intFromPtr(di.section(.eh_frame_hdr).?.ptr),
+ context.pc,
+ &cie,
+ &fde,
+ );
+ } else {
+ const index = std.sort.binarySearch(FrameDescriptionEntry, context.pc, di.fde_list.items, {}, struct {
+ pub fn compareFn(_: void, pc: usize, mid_item: FrameDescriptionEntry) std.math.Order {
+ if (pc < mid_item.pc_begin) return .lt;
+
+ const range_end = mid_item.pc_begin + mid_item.pc_range;
+ if (pc < range_end) return .eq;
+
+ return .gt;
+ }
+ }.compareFn);
+
+ fde = if (index) |i| di.fde_list.items[i] else return error.MissingFDE;
+ cie = di.cie_map.get(fde.cie_length_offset) orelse return error.MissingCIE;
+ }
+
+ var expression_context = .{
+ .is_64 = cie.is_64,
+ .isValidMemory = context.isValidMemory,
+ .compile_unit = di.findCompileUnit(fde.pc_begin) catch null,
+ .thread_context = context.thread_context,
+ .reg_context = context.reg_context,
+ .cfa = context.cfa,
+ };
+
+ context.vm.reset();
+ context.reg_context.eh_frame = cie.version != 4;
+ context.reg_context.is_macho = di.is_macho;
+
+ const row = try context.vm.runToNative(context.allocator, context.pc, cie, fde);
+ context.cfa = switch (row.cfa.rule) {
+ .val_offset => |offset| blk: {
+ const register = row.cfa.register orelse return error.InvalidCFARule;
+ const value = mem.readIntSliceNative(usize, try abi.regBytes(context.thread_context, register, context.reg_context));
+ break :blk try call_frame.applyOffset(value, offset);
+ },
+ .expression => |expression| blk: {
+ context.stack_machine.reset();
+ const value = try context.stack_machine.run(
+ expression,
+ context.allocator,
+ expression_context,
+ context.cfa,
+ );
+
+ if (value) |v| {
+ if (v != .generic) return error.InvalidExpressionValue;
+ break :blk v.generic;
+ } else return error.NoExpressionValue;
+ },
+ else => return error.InvalidCFARule,
+ };
+
+ if (!context.isValidMemory(context.cfa.?)) return error.InvalidCFA;
+ expression_context.cfa = context.cfa;
+
+ // Buffering the modifications is done because copying the thread context is not portable,
+ // some implementations (ie. darwin) use internal pointers to the mcontext.
+ var arena = std.heap.ArenaAllocator.init(context.allocator);
+ defer arena.deinit();
+ const update_allocator = arena.allocator();
+
+ const RegisterUpdate = struct {
+ // Backed by thread_context
+ dest: []u8,
+ // Backed by arena
+ src: []const u8,
+ prev: ?*@This(),
+ };
+
+ var update_tail: ?*RegisterUpdate = null;
+ var has_return_address = true;
+ for (context.vm.rowColumns(row)) |column| {
+ if (column.register) |register| {
+ if (register == cie.return_address_register) {
+ has_return_address = column.rule != .undefined;
+ }
+
+ const dest = try abi.regBytes(context.thread_context, register, context.reg_context);
+ const src = try update_allocator.alloc(u8, dest.len);
+
+ const prev = update_tail;
+ update_tail = try update_allocator.create(RegisterUpdate);
+ update_tail.?.* = .{
+ .dest = dest,
+ .src = src,
+ .prev = prev,
+ };
+
+ try column.resolveValue(
+ context,
+ expression_context,
+ src,
+ );
+ }
+ }
+
+ // On all implemented architectures, the CFA is defined as being the previous frame's SP
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(context.reg_context), context.reg_context)).* = context.cfa.?;
+
+ while (update_tail) |tail| {
+ @memcpy(tail.dest, tail.src);
+ update_tail = tail.prev;
+ }
+
+ if (has_return_address) {
+ context.pc = abi.stripInstructionPtrAuthCode(mem.readIntSliceNative(usize, try abi.regBytes(
+ context.thread_context,
+ cie.return_address_register,
+ context.reg_context,
+ )));
+ } else {
+ context.pc = 0;
+ }
+
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), context.reg_context)).* = context.pc;
+
+ // The call instruction will have pushed the address of the instruction that follows the call as the return address.
+ // This next instruction may be past the end of the function if the caller was `noreturn` (ie. the last instruction in
+ // the function was the call). If we were to look up an FDE entry using the return address directly, it could end up
+ // either not finding an FDE at all, or using the next FDE in the program, producing incorrect results. To prevent this,
+ // we subtract one so that the next lookup is guaranteed to land inside the
+ //
+ // The exception to this rule is signal frames, where we return execution would be returned to the instruction
+ // that triggered the handler.
+ const return_address = context.pc;
+ if (context.pc > 0 and !cie.isSignalFrame()) context.pc -= 1;
+
+ return return_address;
+ }
+};
+
+/// Returns the DWARF register number for an x86_64 register number found in compact unwind info
+fn compactUnwindToDwarfRegNumber(unwind_reg_number: u3) !u8 {
+ return switch (unwind_reg_number) {
+ 1 => 3, // RBX
+ 2 => 12, // R12
+ 3 => 13, // R13
+ 4 => 14, // R14
+ 5 => 15, // R15
+ 6 => 6, // RBP
+ else => error.InvalidUnwindRegisterNumber,
+ };
+}
+
+const macho = std.macho;
+
+/// Unwind a frame using MachO compact unwind info (from __unwind_info).
+/// If the compact encoding can't encode a way to unwind a frame, it will
+/// defer unwinding to DWARF, in which case `.eh_frame` will be used if available.
+pub fn unwindFrameMachO(context: *UnwindContext, unwind_info: []const u8, eh_frame: ?[]const u8, module_base_address: usize) !usize {
+ const header = mem.bytesAsValue(
+ macho.unwind_info_section_header,
+ unwind_info[0..@sizeOf(macho.unwind_info_section_header)],
+ );
+ const indices = mem.bytesAsSlice(
+ macho.unwind_info_section_header_index_entry,
+ unwind_info[header.indexSectionOffset..][0 .. header.indexCount * @sizeOf(macho.unwind_info_section_header_index_entry)],
+ );
+ if (indices.len == 0) return error.MissingUnwindInfo;
+
+ const mapped_pc = context.pc - module_base_address;
+ const second_level_index = blk: {
+ var left: usize = 0;
+ var len: usize = indices.len;
+
+ while (len > 1) {
+ const mid = left + len / 2;
+ const offset = indices[mid].functionOffset;
+ if (mapped_pc < offset) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (mapped_pc == offset) break;
+ len -= len / 2;
+ }
+ }
+
+ // Last index is a sentinel containing the highest address as its functionOffset
+ if (indices[left].secondLevelPagesSectionOffset == 0) return error.MissingUnwindInfo;
+ break :blk &indices[left];
+ };
+
+ const common_encodings = mem.bytesAsSlice(
+ macho.compact_unwind_encoding_t,
+ unwind_info[header.commonEncodingsArraySectionOffset..][0 .. header.commonEncodingsArrayCount * @sizeOf(macho.compact_unwind_encoding_t)],
+ );
+
+ const start_offset = second_level_index.secondLevelPagesSectionOffset;
+ const kind = mem.bytesAsValue(
+ macho.UNWIND_SECOND_LEVEL,
+ unwind_info[start_offset..][0..@sizeOf(macho.UNWIND_SECOND_LEVEL)],
+ );
+
+ const entry: struct {
+ function_offset: usize,
+ raw_encoding: u32,
+ } = switch (kind.*) {
+ .REGULAR => blk: {
+ const page_header = mem.bytesAsValue(
+ macho.unwind_info_regular_second_level_page_header,
+ unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_regular_second_level_page_header)],
+ );
+
+ const entries = mem.bytesAsSlice(
+ macho.unwind_info_regular_second_level_entry,
+ unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.unwind_info_regular_second_level_entry)],
+ );
+ if (entries.len == 0) return error.InvalidUnwindInfo;
+
+ var left: usize = 0;
+ var len: usize = entries.len;
+ while (len > 1) {
+ const mid = left + len / 2;
+ const offset = entries[mid].functionOffset;
+ if (mapped_pc < offset) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (mapped_pc == offset) break;
+ len -= len / 2;
+ }
+ }
+
+ break :blk .{
+ .function_offset = entries[left].functionOffset,
+ .raw_encoding = entries[left].encoding,
+ };
+ },
+ .COMPRESSED => blk: {
+ const page_header = mem.bytesAsValue(
+ macho.unwind_info_compressed_second_level_page_header,
+ unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_compressed_second_level_page_header)],
+ );
+
+ const entries = mem.bytesAsSlice(
+ macho.UnwindInfoCompressedEntry,
+ unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.UnwindInfoCompressedEntry)],
+ );
+ if (entries.len == 0) return error.InvalidUnwindInfo;
+
+ var left: usize = 0;
+ var len: usize = entries.len;
+ while (len > 1) {
+ const mid = left + len / 2;
+ const offset = second_level_index.functionOffset + entries[mid].funcOffset;
+ if (mapped_pc < offset) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (mapped_pc == offset) break;
+ len -= len / 2;
+ }
+ }
+
+ const entry = entries[left];
+ const function_offset = second_level_index.functionOffset + entry.funcOffset;
+ if (entry.encodingIndex < header.commonEncodingsArrayCount) {
+ if (entry.encodingIndex >= common_encodings.len) return error.InvalidUnwindInfo;
+ break :blk .{
+ .function_offset = function_offset,
+ .raw_encoding = common_encodings[entry.encodingIndex],
+ };
+ } else {
+ const local_index = try std.math.sub(
+ u8,
+ entry.encodingIndex,
+ std.math.cast(u8, header.commonEncodingsArrayCount) orelse return error.InvalidUnwindInfo,
+ );
+ const local_encodings = mem.bytesAsSlice(
+ macho.compact_unwind_encoding_t,
+ unwind_info[start_offset + page_header.encodingsPageOffset ..][0 .. page_header.encodingsCount * @sizeOf(macho.compact_unwind_encoding_t)],
+ );
+ if (local_index >= local_encodings.len) return error.InvalidUnwindInfo;
+ break :blk .{
+ .function_offset = function_offset,
+ .raw_encoding = local_encodings[local_index],
+ };
+ }
+ },
+ else => return error.InvalidUnwindInfo,
+ };
+
+ if (entry.raw_encoding == 0) return error.NoUnwindInfo;
+ const reg_context = abi.RegisterContext{
+ .eh_frame = false,
+ .is_macho = true,
+ };
+
+ const encoding: macho.CompactUnwindEncoding = @bitCast(entry.raw_encoding);
+ const new_ip = switch (builtin.cpu.arch) {
+ .x86_64 => switch (encoding.mode.x86_64) {
+ .OLD => return error.UnimplementedUnwindEncoding,
+ .RBP_FRAME => blk: {
+ const regs: [5]u3 = .{
+ encoding.value.x86_64.frame.reg0,
+ encoding.value.x86_64.frame.reg1,
+ encoding.value.x86_64.frame.reg2,
+ encoding.value.x86_64.frame.reg3,
+ encoding.value.x86_64.frame.reg4,
+ };
+
+ const frame_offset = encoding.value.x86_64.frame.frame_offset * @sizeOf(usize);
+ var max_reg: usize = 0;
+ inline for (regs, 0..) |reg, i| {
+ if (reg > 0) max_reg = i;
+ }
+
+ const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
+ const new_sp = fp + 2 * @sizeOf(usize);
+
+ // Verify the stack range we're about to read register values from
+ if (!context.isValidMemory(new_sp) or !context.isValidMemory(fp - frame_offset + max_reg * @sizeOf(usize))) return error.InvalidUnwindInfo;
+
+ const ip_ptr = fp + @sizeOf(usize);
+ const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+ const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
+
+ (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
+
+ for (regs, 0..) |reg, i| {
+ if (reg == 0) continue;
+ const addr = fp - frame_offset + i * @sizeOf(usize);
+ const reg_number = try compactUnwindToDwarfRegNumber(reg);
+ (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(addr)).*;
+ }
+
+ break :blk new_ip;
+ },
+ .STACK_IMMD,
+ .STACK_IND,
+ => blk: {
+ const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
+ const stack_size = if (encoding.mode.x86_64 == .STACK_IMMD)
+ @as(usize, encoding.value.x86_64.frameless.stack.direct.stack_size) * @sizeOf(usize)
+ else stack_size: {
+ // In .STACK_IND, the stack size is inferred from the subq instruction at the beginning of the function.
+ const sub_offset_addr =
+ module_base_address +
+ entry.function_offset +
+ encoding.value.x86_64.frameless.stack.indirect.sub_offset;
+ if (!context.isValidMemory(sub_offset_addr)) return error.InvalidUnwindInfo;
+
+ // `sub_offset_addr` points to the offset of the literal within the instruction
+ const sub_operand = @as(*align(1) const u32, @ptrFromInt(sub_offset_addr)).*;
+ break :stack_size sub_operand + @sizeOf(usize) * @as(usize, encoding.value.x86_64.frameless.stack.indirect.stack_adjust);
+ };
+
+ // Decode the Lehmer-coded sequence of registers.
+ // For a description of the encoding see lib/libc/include/any-macos.13-any/mach-o/compact_unwind_encoding.h
+
+ // Decode the variable-based permutation number into its digits. Each digit represents
+ // an index into the list of register numbers that weren't yet used in the sequence at
+ // the time the digit was added.
+ const reg_count = encoding.value.x86_64.frameless.stack_reg_count;
+ const ip_ptr = if (reg_count > 0) reg_blk: {
+ var digits: [6]u3 = undefined;
+ var accumulator: usize = encoding.value.x86_64.frameless.stack_reg_permutation;
+ var base: usize = 2;
+ for (0..reg_count) |i| {
+ const div = accumulator / base;
+ digits[digits.len - 1 - i] = @intCast(accumulator - base * div);
+ accumulator = div;
+ base += 1;
+ }
+
+ const reg_numbers = [_]u3{ 1, 2, 3, 4, 5, 6 };
+ var registers: [reg_numbers.len]u3 = undefined;
+ var used_indices = [_]bool{false} ** reg_numbers.len;
+ for (digits[digits.len - reg_count ..], 0..) |target_unused_index, i| {
+ var unused_count: u8 = 0;
+ const unused_index = for (used_indices, 0..) |used, index| {
+ if (!used) {
+ if (target_unused_index == unused_count) break index;
+ unused_count += 1;
+ }
+ } else unreachable;
+
+ registers[i] = reg_numbers[unused_index];
+ used_indices[unused_index] = true;
+ }
+
+ var reg_addr = sp + stack_size - @sizeOf(usize) * @as(usize, reg_count + 1);
+ if (!context.isValidMemory(reg_addr)) return error.InvalidUnwindInfo;
+ for (0..reg_count) |i| {
+ const reg_number = try compactUnwindToDwarfRegNumber(registers[i]);
+ (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+ reg_addr += @sizeOf(usize);
+ }
+
+ break :reg_blk reg_addr;
+ } else sp + stack_size - @sizeOf(usize);
+
+ const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+ const new_sp = ip_ptr + @sizeOf(usize);
+ if (!context.isValidMemory(new_sp)) return error.InvalidUnwindInfo;
+
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
+
+ break :blk new_ip;
+ },
+ .DWARF => {
+ return unwindFrameMachODwarf(context, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
+ },
+ },
+ .aarch64 => switch (encoding.mode.arm64) {
+ .OLD => return error.UnimplementedUnwindEncoding,
+ .FRAMELESS => blk: {
+ const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
+ const new_sp = sp + encoding.value.arm64.frameless.stack_size * 16;
+ const new_ip = (try abi.regValueNative(usize, context.thread_context, 30, reg_context)).*;
+ if (!context.isValidMemory(new_sp)) return error.InvalidUnwindInfo;
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
+ break :blk new_ip;
+ },
+ .DWARF => {
+ return unwindFrameMachODwarf(context, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
+ },
+ .FRAME => blk: {
+ const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
+ const new_sp = fp + 16;
+ const ip_ptr = fp + @sizeOf(usize);
+
+ const num_restored_pairs: usize =
+ @popCount(@as(u5, @bitCast(encoding.value.arm64.frame.x_reg_pairs))) +
+ @popCount(@as(u4, @bitCast(encoding.value.arm64.frame.d_reg_pairs)));
+ const min_reg_addr = fp - num_restored_pairs * 2 * @sizeOf(usize);
+
+ if (!context.isValidMemory(new_sp) or !context.isValidMemory(min_reg_addr)) return error.InvalidUnwindInfo;
+
+ var reg_addr = fp - @sizeOf(usize);
+ inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.x_reg_pairs)).Struct.fields, 0..) |field, i| {
+ if (@field(encoding.value.arm64.frame.x_reg_pairs, field.name) != 0) {
+ (try abi.regValueNative(usize, context.thread_context, 19 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+ reg_addr += @sizeOf(usize);
+ (try abi.regValueNative(usize, context.thread_context, 20 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+ reg_addr += @sizeOf(usize);
+ }
+ }
+
+ inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.d_reg_pairs)).Struct.fields, 0..) |field, i| {
+ if (@field(encoding.value.arm64.frame.d_reg_pairs, field.name) != 0) {
+ // Only the lower half of the 128-bit V registers are restored during unwinding
+ @memcpy(
+ try abi.regBytes(context.thread_context, 64 + 8 + i, context.reg_context),
+ mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
+ );
+ reg_addr += @sizeOf(usize);
+ @memcpy(
+ try abi.regBytes(context.thread_context, 64 + 9 + i, context.reg_context),
+ mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
+ );
+ reg_addr += @sizeOf(usize);
+ }
+ }
+
+ const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+ const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
+
+ (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
+
+ break :blk new_ip;
+ },
+ },
+ else => return error.UnimplementedArch,
+ };
+
+ context.pc = abi.stripInstructionPtrAuthCode(new_ip);
+ if (context.pc > 0) context.pc -= 1;
+ return new_ip;
+}
+
+fn unwindFrameMachODwarf(context: *UnwindContext, eh_frame: []const u8, fde_offset: usize) !usize {
+ var di = DwarfInfo{
+ .endian = builtin.cpu.arch.endian(),
+ .is_macho = true,
+ };
+ defer di.deinit(context.allocator);
+
+ di.sections[@intFromEnum(DwarfSection.eh_frame)] = .{
+ .data = eh_frame,
+ .owned = false,
+ };
+
+ return di.unwindFrame(context, fde_offset);
+}
+
+pub const UnwindContext = struct {
+ allocator: mem.Allocator,
+ cfa: ?usize,
+ pc: usize,
+ thread_context: *debug.ThreadContext,
+ reg_context: abi.RegisterContext,
+ isValidMemory: *const fn (address: usize) bool,
+ vm: call_frame.VirtualMachine = .{},
+ stack_machine: expressions.StackMachine(.{ .call_frame_context = true }) = .{},
+
+ pub fn init(allocator: mem.Allocator, thread_context: *const debug.ThreadContext, isValidMemory: *const fn (address: usize) bool) !UnwindContext {
+ const pc = abi.stripInstructionPtrAuthCode((try abi.regValueNative(usize, thread_context, abi.ipRegNum(), null)).*);
+
+ const context_copy = try allocator.create(debug.ThreadContext);
+ debug.copyContext(thread_context, context_copy);
+
+ return .{
+ .allocator = allocator,
+ .cfa = null,
+ .pc = pc,
+ .thread_context = context_copy,
+ .reg_context = undefined,
+ .isValidMemory = isValidMemory,
+ };
+ }
+
+ pub fn deinit(self: *UnwindContext) void {
+ self.vm.deinit(self.allocator);
+ self.stack_machine.deinit(self.allocator);
+ self.allocator.destroy(self.thread_context);
+ }
+
+ pub fn getFp(self: *const UnwindContext) !usize {
+ return (try abi.regValueNative(usize, self.thread_context, abi.fpRegNum(self.reg_context), self.reg_context)).*;
+ }
};
/// Initialize DWARF info. The caller has the responsibility to initialize most
-/// the DwarfInfo fields before calling.
+/// the DwarfInfo fields before calling. `binary_mem` is the raw bytes of the
+/// main binary file (not the secondary debug info file).
pub fn openDwarfDebugInfo(di: *DwarfInfo, allocator: mem.Allocator) !void {
try di.scanAllFunctions(allocator);
try di.scanAllCompileUnits(allocator);
@@ -1477,3 +2265,561 @@ fn getStringGeneric(opt_str: ?[]const u8, offset: u64) ![:0]const u8 {
const last = mem.indexOfScalarPos(u8, str, casted_offset, 0) orelse return badDwarf();
return str[casted_offset..last :0];
}
+
+const EhPointerContext = struct {
+ // The address of the pointer field itself
+ pc_rel_base: u64,
+
+ // Whether or not to follow indirect pointers. This should only be
+ // used when decoding pointers at runtime using the current process's
+ // debug info
+ follow_indirect: bool,
+
+ // These relative addressing modes are only used in specific cases, and
+ // might not be available / required in all parsing contexts
+ data_rel_base: ?u64 = null,
+ text_rel_base: ?u64 = null,
+ function_rel_base: ?u64 = null,
+};
+
+fn readEhPointer(reader: anytype, enc: u8, addr_size_bytes: u8, ctx: EhPointerContext, endian: std.builtin.Endian) !?u64 {
+ if (enc == EH.PE.omit) return null;
+
+ const value: union(enum) {
+ signed: i64,
+ unsigned: u64,
+ } = switch (enc & EH.PE.type_mask) {
+ EH.PE.absptr => .{
+ .unsigned = switch (addr_size_bytes) {
+ 2 => try reader.readInt(u16, endian),
+ 4 => try reader.readInt(u32, endian),
+ 8 => try reader.readInt(u64, endian),
+ else => return error.InvalidAddrSize,
+ },
+ },
+ EH.PE.uleb128 => .{ .unsigned = try leb.readULEB128(u64, reader) },
+ EH.PE.udata2 => .{ .unsigned = try reader.readInt(u16, endian) },
+ EH.PE.udata4 => .{ .unsigned = try reader.readInt(u32, endian) },
+ EH.PE.udata8 => .{ .unsigned = try reader.readInt(u64, endian) },
+ EH.PE.sleb128 => .{ .signed = try leb.readILEB128(i64, reader) },
+ EH.PE.sdata2 => .{ .signed = try reader.readInt(i16, endian) },
+ EH.PE.sdata4 => .{ .signed = try reader.readInt(i32, endian) },
+ EH.PE.sdata8 => .{ .signed = try reader.readInt(i64, endian) },
+ else => return badDwarf(),
+ };
+
+ var base = switch (enc & EH.PE.rel_mask) {
+ EH.PE.pcrel => ctx.pc_rel_base,
+ EH.PE.textrel => ctx.text_rel_base orelse return error.PointerBaseNotSpecified,
+ EH.PE.datarel => ctx.data_rel_base orelse return error.PointerBaseNotSpecified,
+ EH.PE.funcrel => ctx.function_rel_base orelse return error.PointerBaseNotSpecified,
+ else => null,
+ };
+
+ const ptr: u64 = if (base) |b| switch (value) {
+ .signed => |s| @intCast(try math.add(i64, s, @as(i64, @intCast(b)))),
+ // absptr can actually contain signed values in some cases (aarch64 MachO)
+ .unsigned => |u| u +% b,
+ } else switch (value) {
+ .signed => |s| @as(u64, @intCast(s)),
+ .unsigned => |u| u,
+ };
+
+ if ((enc & EH.PE.indirect) > 0 and ctx.follow_indirect) {
+ if (@sizeOf(usize) != addr_size_bytes) {
+ // See the documentation for `follow_indirect`
+ return error.NonNativeIndirection;
+ }
+
+ const native_ptr = math.cast(usize, ptr) orelse return error.PointerOverflow;
+ return switch (addr_size_bytes) {
+ 2, 4, 8 => return @as(*const usize, @ptrFromInt(native_ptr)).*,
+ else => return error.UnsupportedAddrSize,
+ };
+ } else {
+ return ptr;
+ }
+}
+
+/// This represents the decoded .eh_frame_hdr header
+pub const ExceptionFrameHeader = struct {
+ eh_frame_ptr: usize,
+ table_enc: u8,
+ fde_count: usize,
+ entries: []const u8,
+
+ pub fn entrySize(table_enc: u8) !u8 {
+ return switch (table_enc & EH.PE.type_mask) {
+ EH.PE.udata2,
+ EH.PE.sdata2,
+ => 4,
+ EH.PE.udata4,
+ EH.PE.sdata4,
+ => 8,
+ EH.PE.udata8,
+ EH.PE.sdata8,
+ => 16,
+ // This is a binary search table, so all entries must be the same length
+ else => return badDwarf(),
+ };
+ }
+
+ fn isValidPtr(
+ self: ExceptionFrameHeader,
+ ptr: usize,
+ isValidMemory: *const fn (address: usize) bool,
+ eh_frame_len: ?usize,
+ ) bool {
+ if (eh_frame_len) |len| {
+ return ptr >= self.eh_frame_ptr and ptr < self.eh_frame_ptr + len;
+ } else {
+ return isValidMemory(ptr);
+ }
+ }
+
+ /// Find an entry by binary searching the eh_frame_hdr section.
+ ///
+ /// Since the length of the eh_frame section (`eh_frame_len`) may not be known by the caller,
+ /// `isValidMemory` will be called before accessing any memory referenced by
+ /// the header entries. If `eh_frame_len` is provided, then these checks can be skipped.
+ pub fn findEntry(
+ self: ExceptionFrameHeader,
+ isValidMemory: *const fn (address: usize) bool,
+ eh_frame_len: ?usize,
+ eh_frame_hdr_ptr: usize,
+ pc: usize,
+ cie: *CommonInformationEntry,
+ fde: *FrameDescriptionEntry,
+ ) !void {
+ const entry_size = try entrySize(self.table_enc);
+
+ var left: usize = 0;
+ var len: usize = self.fde_count;
+
+ var stream = io.fixedBufferStream(self.entries);
+ const reader = stream.reader();
+
+ while (len > 1) {
+ const mid = left + len / 2;
+
+ try stream.seekTo(mid * entry_size);
+ const pc_begin = try readEhPointer(reader, self.table_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&self.entries[stream.pos]),
+ .follow_indirect = true,
+ .data_rel_base = eh_frame_hdr_ptr,
+ }, builtin.cpu.arch.endian()) orelse return badDwarf();
+
+ if (pc < pc_begin) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (pc == pc_begin) break;
+ len -= len / 2;
+ }
+ }
+
+ if (len == 0) return badDwarf();
+ try stream.seekTo(left * entry_size);
+
+ // Read past the pc_begin field of the entry
+ _ = try readEhPointer(reader, self.table_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&self.entries[stream.pos]),
+ .follow_indirect = true,
+ .data_rel_base = eh_frame_hdr_ptr,
+ }, builtin.cpu.arch.endian()) orelse return badDwarf();
+
+ const fde_ptr = math.cast(usize, try readEhPointer(reader, self.table_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&self.entries[stream.pos]),
+ .follow_indirect = true,
+ .data_rel_base = eh_frame_hdr_ptr,
+ }, builtin.cpu.arch.endian()) orelse return badDwarf()) orelse return badDwarf();
+
+ // Verify the length fields of the FDE header are readable
+ if (!self.isValidPtr(fde_ptr, isValidMemory, eh_frame_len) or fde_ptr < self.eh_frame_ptr) return badDwarf();
+
+ var fde_entry_header_len: usize = 4;
+ if (!self.isValidPtr(fde_ptr + 3, isValidMemory, eh_frame_len)) return badDwarf();
+ if (self.isValidPtr(fde_ptr + 11, isValidMemory, eh_frame_len)) fde_entry_header_len = 12;
+
+ // Even if eh_frame_len is not specified, all ranges accssed are checked by isValidPtr
+ const eh_frame = @as([*]const u8, @ptrFromInt(self.eh_frame_ptr))[0 .. eh_frame_len orelse math.maxInt(u32)];
+
+ const fde_offset = fde_ptr - self.eh_frame_ptr;
+ var eh_frame_stream = io.fixedBufferStream(eh_frame);
+ try eh_frame_stream.seekTo(fde_offset);
+
+ const fde_entry_header = try EntryHeader.read(&eh_frame_stream, .eh_frame, builtin.cpu.arch.endian());
+ if (!self.isValidPtr(@intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), isValidMemory, eh_frame_len)) return badDwarf();
+ if (fde_entry_header.type != .fde) return badDwarf();
+
+ // CIEs always come before FDEs (the offset is a subtraction), so we can assume this memory is readable
+ const cie_offset = fde_entry_header.type.fde;
+ try eh_frame_stream.seekTo(cie_offset);
+ const cie_entry_header = try EntryHeader.read(&eh_frame_stream, .eh_frame, builtin.cpu.arch.endian());
+ if (!self.isValidPtr(@intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), isValidMemory, eh_frame_len)) return badDwarf();
+ if (cie_entry_header.type != .cie) return badDwarf();
+
+ cie.* = try CommonInformationEntry.parse(
+ cie_entry_header.entry_bytes,
+ 0,
+ true,
+ cie_entry_header.is_64,
+ .eh_frame,
+ cie_entry_header.length_offset,
+ @sizeOf(usize),
+ builtin.cpu.arch.endian(),
+ );
+
+ fde.* = try FrameDescriptionEntry.parse(
+ fde_entry_header.entry_bytes,
+ 0,
+ true,
+ cie.*,
+ @sizeOf(usize),
+ builtin.cpu.arch.endian(),
+ );
+ }
+};
+
+pub const EntryHeader = struct {
+ /// Offset of the length field in the backing buffer
+ length_offset: usize,
+ is_64: bool,
+ type: union(enum) {
+ cie,
+ /// Value is the offset of the corresponding CIE
+ fde: u64,
+ terminator: void,
+ },
+ /// The entry's contents, not including the ID field
+ entry_bytes: []const u8,
+
+ /// Reads a header for either an FDE or a CIE, then advances the stream to the position after the trailing structure.
+ /// `stream` must be a stream backed by either the .eh_frame or .debug_frame sections.
+ pub fn read(stream: *std.io.FixedBufferStream([]const u8), dwarf_section: DwarfSection, endian: std.builtin.Endian) !EntryHeader {
+ assert(dwarf_section == .eh_frame or dwarf_section == .debug_frame);
+
+ const reader = stream.reader();
+ const length_offset = stream.pos;
+
+ var is_64: bool = undefined;
+ const length = math.cast(usize, try readUnitLength(reader, endian, &is_64)) orelse return badDwarf();
+ if (length == 0) return .{
+ .length_offset = length_offset,
+ .is_64 = is_64,
+ .type = .{ .terminator = {} },
+ .entry_bytes = &.{},
+ };
+
+ const id_len = @as(u8, if (is_64) 8 else 4);
+ const id = if (is_64) try reader.readInt(u64, endian) else try reader.readInt(u32, endian);
+ const entry_bytes = stream.buffer[stream.pos..][0 .. length - id_len];
+ const cie_id: u64 = switch (dwarf_section) {
+ .eh_frame => CommonInformationEntry.eh_id,
+ .debug_frame => if (is_64) CommonInformationEntry.dwarf64_id else CommonInformationEntry.dwarf32_id,
+ else => unreachable,
+ };
+
+ const result = EntryHeader{
+ .length_offset = length_offset,
+ .is_64 = is_64,
+ .type = if (id == cie_id) .{ .cie = {} } else .{
+ .fde = switch (dwarf_section) {
+ .eh_frame => try std.math.sub(u64, stream.pos - id_len, id),
+ .debug_frame => id,
+ else => unreachable,
+ },
+ },
+ .entry_bytes = entry_bytes,
+ };
+
+ stream.pos += entry_bytes.len;
+ return result;
+ }
+
+ /// The length of the entry including the ID field, but not the length field itself
+ pub fn entryLength(self: EntryHeader) usize {
+ return self.entry_bytes.len + @as(u8, if (self.is_64) 8 else 4);
+ }
+};
+
+pub const CommonInformationEntry = struct {
+ // Used in .eh_frame
+ pub const eh_id = 0;
+
+ // Used in .debug_frame (DWARF32)
+ pub const dwarf32_id = math.maxInt(u32);
+
+ // Used in .debug_frame (DWARF64)
+ pub const dwarf64_id = math.maxInt(u64);
+
+ // Offset of the length field of this entry in the eh_frame section.
+ // This is the key that FDEs use to reference CIEs.
+ length_offset: u64,
+ version: u8,
+ address_size: u8,
+ is_64: bool,
+
+ // Only present in version 4
+ segment_selector_size: ?u8,
+
+ code_alignment_factor: u32,
+ data_alignment_factor: i32,
+ return_address_register: u8,
+
+ aug_str: []const u8,
+ aug_data: []const u8,
+ lsda_pointer_enc: u8,
+ personality_enc: ?u8,
+ personality_routine_pointer: ?u64,
+ fde_pointer_enc: u8,
+ initial_instructions: []const u8,
+
+ pub fn isSignalFrame(self: CommonInformationEntry) bool {
+ for (self.aug_str) |c| if (c == 'S') return true;
+ return false;
+ }
+
+ pub fn addressesSignedWithBKey(self: CommonInformationEntry) bool {
+ for (self.aug_str) |c| if (c == 'B') return true;
+ return false;
+ }
+
+ pub fn mteTaggedFrame(self: CommonInformationEntry) bool {
+ for (self.aug_str) |c| if (c == 'G') return true;
+ return false;
+ }
+
+ /// This function expects to read the CIE starting with the version field.
+ /// The returned struct references memory backed by cie_bytes.
+ ///
+ /// See the FrameDescriptionEntry.parse documentation for the description
+ /// of `pc_rel_offset` and `is_runtime`.
+ ///
+ /// `length_offset` specifies the offset of this CIE's length field in the
+ /// .eh_frame / .debug_frame section.
+ pub fn parse(
+ cie_bytes: []const u8,
+ pc_rel_offset: i64,
+ is_runtime: bool,
+ is_64: bool,
+ dwarf_section: DwarfSection,
+ length_offset: u64,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !CommonInformationEntry {
+ if (addr_size_bytes > 8) return error.UnsupportedAddrSize;
+
+ var stream = io.fixedBufferStream(cie_bytes);
+ const reader = stream.reader();
+
+ const version = try reader.readByte();
+ switch (dwarf_section) {
+ .eh_frame => if (version != 1 and version != 3) return error.UnsupportedDwarfVersion,
+ .debug_frame => if (version != 4) return error.UnsupportedDwarfVersion,
+ else => return error.UnsupportedDwarfSection,
+ }
+
+ var has_eh_data = false;
+ var has_aug_data = false;
+
+ var aug_str_len: usize = 0;
+ var aug_str_start = stream.pos;
+ var aug_byte = try reader.readByte();
+ while (aug_byte != 0) : (aug_byte = try reader.readByte()) {
+ switch (aug_byte) {
+ 'z' => {
+ if (aug_str_len != 0) return badDwarf();
+ has_aug_data = true;
+ },
+ 'e' => {
+ if (has_aug_data or aug_str_len != 0) return badDwarf();
+ if (try reader.readByte() != 'h') return badDwarf();
+ has_eh_data = true;
+ },
+ else => if (has_eh_data) return badDwarf(),
+ }
+
+ aug_str_len += 1;
+ }
+
+ if (has_eh_data) {
+ // legacy data created by older versions of gcc - unsupported here
+ for (0..addr_size_bytes) |_| _ = try reader.readByte();
+ }
+
+ const address_size = if (version == 4) try reader.readByte() else addr_size_bytes;
+ const segment_selector_size = if (version == 4) try reader.readByte() else null;
+
+ const code_alignment_factor = try leb.readULEB128(u32, reader);
+ const data_alignment_factor = try leb.readILEB128(i32, reader);
+ const return_address_register = if (version == 1) try reader.readByte() else try leb.readULEB128(u8, reader);
+
+ var lsda_pointer_enc: u8 = EH.PE.omit;
+ var personality_enc: ?u8 = null;
+ var personality_routine_pointer: ?u64 = null;
+ var fde_pointer_enc: u8 = EH.PE.absptr;
+
+ var aug_data: []const u8 = &[_]u8{};
+ const aug_str = if (has_aug_data) blk: {
+ const aug_data_len = try leb.readULEB128(usize, reader);
+ const aug_data_start = stream.pos;
+ aug_data = cie_bytes[aug_data_start..][0..aug_data_len];
+
+ const aug_str = cie_bytes[aug_str_start..][0..aug_str_len];
+ for (aug_str[1..]) |byte| {
+ switch (byte) {
+ 'L' => {
+ lsda_pointer_enc = try reader.readByte();
+ },
+ 'P' => {
+ personality_enc = try reader.readByte();
+ personality_routine_pointer = try readEhPointer(
+ reader,
+ personality_enc.?,
+ addr_size_bytes,
+ .{
+ .pc_rel_base = try pcRelBase(@intFromPtr(&cie_bytes[stream.pos]), pc_rel_offset),
+ .follow_indirect = is_runtime,
+ },
+ endian,
+ );
+ },
+ 'R' => {
+ fde_pointer_enc = try reader.readByte();
+ },
+ 'S', 'B', 'G' => {},
+ else => return badDwarf(),
+ }
+ }
+
+ // aug_data_len can include padding so the CIE ends on an address boundary
+ try stream.seekTo(aug_data_start + aug_data_len);
+ break :blk aug_str;
+ } else &[_]u8{};
+
+ const initial_instructions = cie_bytes[stream.pos..];
+ return .{
+ .length_offset = length_offset,
+ .version = version,
+ .address_size = address_size,
+ .is_64 = is_64,
+ .segment_selector_size = segment_selector_size,
+ .code_alignment_factor = code_alignment_factor,
+ .data_alignment_factor = data_alignment_factor,
+ .return_address_register = return_address_register,
+ .aug_str = aug_str,
+ .aug_data = aug_data,
+ .lsda_pointer_enc = lsda_pointer_enc,
+ .personality_enc = personality_enc,
+ .personality_routine_pointer = personality_routine_pointer,
+ .fde_pointer_enc = fde_pointer_enc,
+ .initial_instructions = initial_instructions,
+ };
+ }
+};
+
+pub const FrameDescriptionEntry = struct {
+ // Offset into eh_frame where the CIE for this FDE is stored
+ cie_length_offset: u64,
+
+ pc_begin: u64,
+ pc_range: u64,
+ lsda_pointer: ?u64,
+ aug_data: []const u8,
+ instructions: []const u8,
+
+ /// This function expects to read the FDE starting at the PC Begin field.
+ /// The returned struct references memory backed by `fde_bytes`.
+ ///
+ /// `pc_rel_offset` specifies an offset to be applied to pc_rel_base values
+ /// used when decoding pointers. This should be set to zero if fde_bytes is
+ /// backed by the memory of a .eh_frame / .debug_frame section in the running executable.
+ /// Otherwise, it should be the relative offset to translate addresses from
+ /// where the section is currently stored in memory, to where it *would* be
+ /// stored at runtime: section base addr - backing data base ptr.
+ ///
+ /// Similarly, `is_runtime` specifies this function is being called on a runtime
+ /// section, and so indirect pointers can be followed.
+ pub fn parse(
+ fde_bytes: []const u8,
+ pc_rel_offset: i64,
+ is_runtime: bool,
+ cie: CommonInformationEntry,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !FrameDescriptionEntry {
+ if (addr_size_bytes > 8) return error.InvalidAddrSize;
+
+ var stream = io.fixedBufferStream(fde_bytes);
+ const reader = stream.reader();
+
+ const pc_begin = try readEhPointer(
+ reader,
+ cie.fde_pointer_enc,
+ addr_size_bytes,
+ .{
+ .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[stream.pos]), pc_rel_offset),
+ .follow_indirect = is_runtime,
+ },
+ endian,
+ ) orelse return badDwarf();
+
+ const pc_range = try readEhPointer(
+ reader,
+ cie.fde_pointer_enc,
+ addr_size_bytes,
+ .{
+ .pc_rel_base = 0,
+ .follow_indirect = false,
+ },
+ endian,
+ ) orelse return badDwarf();
+
+ var aug_data: []const u8 = &[_]u8{};
+ const lsda_pointer = if (cie.aug_str.len > 0) blk: {
+ const aug_data_len = try leb.readULEB128(usize, reader);
+ const aug_data_start = stream.pos;
+ aug_data = fde_bytes[aug_data_start..][0..aug_data_len];
+
+ const lsda_pointer = if (cie.lsda_pointer_enc != EH.PE.omit)
+ try readEhPointer(
+ reader,
+ cie.lsda_pointer_enc,
+ addr_size_bytes,
+ .{
+ .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[stream.pos]), pc_rel_offset),
+ .follow_indirect = is_runtime,
+ },
+ endian,
+ )
+ else
+ null;
+
+ try stream.seekTo(aug_data_start + aug_data_len);
+ break :blk lsda_pointer;
+ } else null;
+
+ const instructions = fde_bytes[stream.pos..];
+ return .{
+ .cie_length_offset = cie.length_offset,
+ .pc_begin = pc_begin,
+ .pc_range = pc_range,
+ .lsda_pointer = lsda_pointer,
+ .aug_data = aug_data,
+ .instructions = instructions,
+ };
+ }
+};
+
+fn pcRelBase(field_ptr: usize, pc_rel_offset: i64) !usize {
+ if (pc_rel_offset < 0) {
+ return math.sub(usize, field_ptr, @as(usize, @intCast(-pc_rel_offset)));
+ } else {
+ return math.add(usize, field_ptr, @as(usize, @intCast(pc_rel_offset)));
+ }
+}
+
+test {
+ std.testing.refAllDecls(@This());
+}
diff --git a/lib/std/dwarf/EH.zig b/lib/std/dwarf/EH.zig
@@ -0,0 +1,27 @@
+pub const PE = struct {
+ pub const absptr = 0x00;
+
+ pub const size_mask = 0x7;
+ pub const sign_mask = 0x8;
+ pub const type_mask = size_mask | sign_mask;
+
+ pub const uleb128 = 0x01;
+ pub const udata2 = 0x02;
+ pub const udata4 = 0x03;
+ pub const udata8 = 0x04;
+ pub const sleb128 = 0x09;
+ pub const sdata2 = 0x0A;
+ pub const sdata4 = 0x0B;
+ pub const sdata8 = 0x0C;
+
+ pub const rel_mask = 0x70;
+ pub const pcrel = 0x10;
+ pub const textrel = 0x20;
+ pub const datarel = 0x30;
+ pub const funcrel = 0x40;
+ pub const aligned = 0x50;
+
+ pub const indirect = 0x80;
+
+ pub const omit = 0xff;
+};
diff --git a/lib/std/dwarf/abi.zig b/lib/std/dwarf/abi.zig
@@ -0,0 +1,387 @@
+const builtin = @import("builtin");
+const std = @import("../std.zig");
+const os = std.os;
+const mem = std.mem;
+
+pub fn isSupportedArch(arch: std.Target.Cpu.Arch) bool {
+ return switch (arch) {
+ .x86,
+ .x86_64,
+ .arm,
+ .aarch64,
+ => true,
+ else => false,
+ };
+}
+
+pub fn ipRegNum() u8 {
+ return switch (builtin.cpu.arch) {
+ .x86 => 8,
+ .x86_64 => 16,
+ .arm => 15,
+ .aarch64 => 32,
+ else => unreachable,
+ };
+}
+
+pub fn fpRegNum(reg_context: RegisterContext) u8 {
+ return switch (builtin.cpu.arch) {
+ // GCC on OS X historicaly did the opposite of ELF for these registers (only in .eh_frame), and that is now the convention for MachO
+ .x86 => if (reg_context.eh_frame and reg_context.is_macho) 4 else 5,
+ .x86_64 => 6,
+ .arm => 11,
+ .aarch64 => 29,
+ else => unreachable,
+ };
+}
+
+pub fn spRegNum(reg_context: RegisterContext) u8 {
+ return switch (builtin.cpu.arch) {
+ .x86 => if (reg_context.eh_frame and reg_context.is_macho) 5 else 4,
+ .x86_64 => 7,
+ .arm => 13,
+ .aarch64 => 31,
+ else => unreachable,
+ };
+}
+
+/// Some platforms use pointer authentication - the upper bits of instruction pointers contain a signature.
+/// This function clears these signature bits to make the pointer usable.
+pub inline fn stripInstructionPtrAuthCode(ptr: usize) usize {
+ if (builtin.cpu.arch == .aarch64) {
+ // `hint 0x07` maps to `xpaclri` (or `nop` if the hardware doesn't support it)
+ // The save / restore is because `xpaclri` operates on x30 (LR)
+ return asm (
+ \\mov x16, x30
+ \\mov x30, x15
+ \\hint 0x07
+ \\mov x15, x30
+ \\mov x30, x16
+ : [ret] "={x15}" (-> usize),
+ : [ptr] "{x15}" (ptr),
+ : "x16"
+ );
+ }
+
+ return ptr;
+}
+
+pub const RegisterContext = struct {
+ eh_frame: bool,
+ is_macho: bool,
+};
+
+pub const AbiError = error{
+ InvalidRegister,
+ UnimplementedArch,
+ UnimplementedOs,
+ RegisterContextRequired,
+ ThreadContextNotSupported,
+};
+
+fn RegValueReturnType(comptime ContextPtrType: type, comptime T: type) type {
+ const reg_bytes_type = comptime RegBytesReturnType(ContextPtrType);
+ const info = @typeInfo(reg_bytes_type).Pointer;
+ return @Type(.{
+ .Pointer = .{
+ .size = .One,
+ .is_const = info.is_const,
+ .is_volatile = info.is_volatile,
+ .is_allowzero = info.is_allowzero,
+ .alignment = info.alignment,
+ .address_space = info.address_space,
+ .child = T,
+ .sentinel = null,
+ },
+ });
+}
+
+/// Returns a pointer to a register stored in a ThreadContext, preserving the pointer attributes of the context.
+pub fn regValueNative(
+ comptime T: type,
+ thread_context_ptr: anytype,
+ reg_number: u8,
+ reg_context: ?RegisterContext,
+) !RegValueReturnType(@TypeOf(thread_context_ptr), T) {
+ const reg_bytes = try regBytes(thread_context_ptr, reg_number, reg_context);
+ if (@sizeOf(T) != reg_bytes.len) return error.IncompatibleRegisterSize;
+ return mem.bytesAsValue(T, reg_bytes[0..@sizeOf(T)]);
+}
+
+fn RegBytesReturnType(comptime ContextPtrType: type) type {
+ const info = @typeInfo(ContextPtrType);
+ if (info != .Pointer or info.Pointer.child != std.debug.ThreadContext) {
+ @compileError("Expected a pointer to std.debug.ThreadContext, got " ++ @typeName(@TypeOf(ContextPtrType)));
+ }
+
+ return if (info.Pointer.is_const) return []const u8 else []u8;
+}
+
+/// Returns a slice containing the backing storage for `reg_number`.
+///
+/// `reg_context` describes in what context the register number is used, as it can have different
+/// meanings depending on the DWARF container. It is only required when getting the stack or
+/// frame pointer register on some architectures.
+pub fn regBytes(
+ thread_context_ptr: anytype,
+ reg_number: u8,
+ reg_context: ?RegisterContext,
+) AbiError!RegBytesReturnType(@TypeOf(thread_context_ptr)) {
+ if (builtin.os.tag == .windows) {
+ return switch (builtin.cpu.arch) {
+ .x86 => switch (reg_number) {
+ 0 => mem.asBytes(&thread_context_ptr.Eax),
+ 1 => mem.asBytes(&thread_context_ptr.Ecx),
+ 2 => mem.asBytes(&thread_context_ptr.Edx),
+ 3 => mem.asBytes(&thread_context_ptr.Ebx),
+ 4 => mem.asBytes(&thread_context_ptr.Esp),
+ 5 => mem.asBytes(&thread_context_ptr.Ebp),
+ 6 => mem.asBytes(&thread_context_ptr.Esi),
+ 7 => mem.asBytes(&thread_context_ptr.Edi),
+ 8 => mem.asBytes(&thread_context_ptr.Eip),
+ 9 => mem.asBytes(&thread_context_ptr.EFlags),
+ 10 => mem.asBytes(&thread_context_ptr.SegCs),
+ 11 => mem.asBytes(&thread_context_ptr.SegSs),
+ 12 => mem.asBytes(&thread_context_ptr.SegDs),
+ 13 => mem.asBytes(&thread_context_ptr.SegEs),
+ 14 => mem.asBytes(&thread_context_ptr.SegFs),
+ 15 => mem.asBytes(&thread_context_ptr.SegGs),
+ else => error.InvalidRegister,
+ },
+ .x86_64 => switch (reg_number) {
+ 0 => mem.asBytes(&thread_context_ptr.Rax),
+ 1 => mem.asBytes(&thread_context_ptr.Rdx),
+ 2 => mem.asBytes(&thread_context_ptr.Rcx),
+ 3 => mem.asBytes(&thread_context_ptr.Rbx),
+ 4 => mem.asBytes(&thread_context_ptr.Rsi),
+ 5 => mem.asBytes(&thread_context_ptr.Rdi),
+ 6 => mem.asBytes(&thread_context_ptr.Rbp),
+ 7 => mem.asBytes(&thread_context_ptr.Rsp),
+ 8 => mem.asBytes(&thread_context_ptr.R8),
+ 9 => mem.asBytes(&thread_context_ptr.R9),
+ 10 => mem.asBytes(&thread_context_ptr.R10),
+ 11 => mem.asBytes(&thread_context_ptr.R11),
+ 12 => mem.asBytes(&thread_context_ptr.R12),
+ 13 => mem.asBytes(&thread_context_ptr.R13),
+ 14 => mem.asBytes(&thread_context_ptr.R14),
+ 15 => mem.asBytes(&thread_context_ptr.R15),
+ 16 => mem.asBytes(&thread_context_ptr.Rip),
+ else => error.InvalidRegister,
+ },
+ .aarch64 => switch (reg_number) {
+ 0...30 => mem.asBytes(&thread_context_ptr.DUMMYUNIONNAME.X[reg_number]),
+ 31 => mem.asBytes(&thread_context_ptr.Sp),
+ 32 => mem.asBytes(&thread_context_ptr.Pc),
+ else => error.InvalidRegister,
+ },
+ else => error.UnimplementedArch,
+ };
+ }
+
+ if (!std.debug.have_ucontext) return error.ThreadContextNotSupported;
+
+ const ucontext_ptr = thread_context_ptr;
+ return switch (builtin.cpu.arch) {
+ .x86 => switch (builtin.os.tag) {
+ .linux, .netbsd, .solaris => switch (reg_number) {
+ 0 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EAX]),
+ 1 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.ECX]),
+ 2 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EDX]),
+ 3 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EBX]),
+ 4...5 => if (reg_context) |r| bytes: {
+ if (reg_number == 4) {
+ break :bytes if (r.eh_frame and r.is_macho)
+ mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EBP])
+ else
+ mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.ESP]);
+ } else {
+ break :bytes if (r.eh_frame and r.is_macho)
+ mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.ESP])
+ else
+ mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EBP]);
+ }
+ } else error.RegisterContextRequired,
+ 6 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.ESI]),
+ 7 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EDI]),
+ 8 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EIP]),
+ 9 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.EFL]),
+ 10 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.CS]),
+ 11 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.SS]),
+ 12 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.DS]),
+ 13 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.ES]),
+ 14 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.FS]),
+ 15 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.GS]),
+ 16...23 => error.InvalidRegister, // TODO: Support loading ST0-ST7 from mcontext.fpregs
+ 32...39 => error.InvalidRegister, // TODO: Support loading XMM0-XMM7 from mcontext.fpregs
+ else => error.InvalidRegister,
+ },
+ else => error.UnimplementedOs,
+ },
+ .x86_64 => switch (builtin.os.tag) {
+ .linux, .netbsd, .solaris => switch (reg_number) {
+ 0 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RAX]),
+ 1 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RDX]),
+ 2 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RCX]),
+ 3 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RBX]),
+ 4 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RSI]),
+ 5 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RDI]),
+ 6 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RBP]),
+ 7 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RSP]),
+ 8 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R8]),
+ 9 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R9]),
+ 10 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R10]),
+ 11 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R11]),
+ 12 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R12]),
+ 13 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R13]),
+ 14 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R14]),
+ 15 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.R15]),
+ 16 => mem.asBytes(&ucontext_ptr.mcontext.gregs[os.REG.RIP]),
+ 17...32 => |i| mem.asBytes(&ucontext_ptr.mcontext.fpregs.xmm[i - 17]),
+ else => error.InvalidRegister,
+ },
+ .freebsd => switch (reg_number) {
+ 0 => mem.asBytes(&ucontext_ptr.mcontext.rax),
+ 1 => mem.asBytes(&ucontext_ptr.mcontext.rdx),
+ 2 => mem.asBytes(&ucontext_ptr.mcontext.rcx),
+ 3 => mem.asBytes(&ucontext_ptr.mcontext.rbx),
+ 4 => mem.asBytes(&ucontext_ptr.mcontext.rsi),
+ 5 => mem.asBytes(&ucontext_ptr.mcontext.rdi),
+ 6 => mem.asBytes(&ucontext_ptr.mcontext.rbp),
+ 7 => mem.asBytes(&ucontext_ptr.mcontext.rsp),
+ 8 => mem.asBytes(&ucontext_ptr.mcontext.r8),
+ 9 => mem.asBytes(&ucontext_ptr.mcontext.r9),
+ 10 => mem.asBytes(&ucontext_ptr.mcontext.r10),
+ 11 => mem.asBytes(&ucontext_ptr.mcontext.r11),
+ 12 => mem.asBytes(&ucontext_ptr.mcontext.r12),
+ 13 => mem.asBytes(&ucontext_ptr.mcontext.r13),
+ 14 => mem.asBytes(&ucontext_ptr.mcontext.r14),
+ 15 => mem.asBytes(&ucontext_ptr.mcontext.r15),
+ 16 => mem.asBytes(&ucontext_ptr.mcontext.rip),
+ // TODO: Extract xmm state from mcontext.fpstate?
+ else => error.InvalidRegister,
+ },
+ .openbsd => switch (reg_number) {
+ 0 => mem.asBytes(&ucontext_ptr.sc_rax),
+ 1 => mem.asBytes(&ucontext_ptr.sc_rdx),
+ 2 => mem.asBytes(&ucontext_ptr.sc_rcx),
+ 3 => mem.asBytes(&ucontext_ptr.sc_rbx),
+ 4 => mem.asBytes(&ucontext_ptr.sc_rsi),
+ 5 => mem.asBytes(&ucontext_ptr.sc_rdi),
+ 6 => mem.asBytes(&ucontext_ptr.sc_rbp),
+ 7 => mem.asBytes(&ucontext_ptr.sc_rsp),
+ 8 => mem.asBytes(&ucontext_ptr.sc_r8),
+ 9 => mem.asBytes(&ucontext_ptr.sc_r9),
+ 10 => mem.asBytes(&ucontext_ptr.sc_r10),
+ 11 => mem.asBytes(&ucontext_ptr.sc_r11),
+ 12 => mem.asBytes(&ucontext_ptr.sc_r12),
+ 13 => mem.asBytes(&ucontext_ptr.sc_r13),
+ 14 => mem.asBytes(&ucontext_ptr.sc_r14),
+ 15 => mem.asBytes(&ucontext_ptr.sc_r15),
+ 16 => mem.asBytes(&ucontext_ptr.sc_rip),
+ // TODO: Extract xmm state from sc_fpstate?
+ else => error.InvalidRegister,
+ },
+ .macos => switch (reg_number) {
+ 0 => mem.asBytes(&ucontext_ptr.mcontext.ss.rax),
+ 1 => mem.asBytes(&ucontext_ptr.mcontext.ss.rdx),
+ 2 => mem.asBytes(&ucontext_ptr.mcontext.ss.rcx),
+ 3 => mem.asBytes(&ucontext_ptr.mcontext.ss.rbx),
+ 4 => mem.asBytes(&ucontext_ptr.mcontext.ss.rsi),
+ 5 => mem.asBytes(&ucontext_ptr.mcontext.ss.rdi),
+ 6 => mem.asBytes(&ucontext_ptr.mcontext.ss.rbp),
+ 7 => mem.asBytes(&ucontext_ptr.mcontext.ss.rsp),
+ 8 => mem.asBytes(&ucontext_ptr.mcontext.ss.r8),
+ 9 => mem.asBytes(&ucontext_ptr.mcontext.ss.r9),
+ 10 => mem.asBytes(&ucontext_ptr.mcontext.ss.r10),
+ 11 => mem.asBytes(&ucontext_ptr.mcontext.ss.r11),
+ 12 => mem.asBytes(&ucontext_ptr.mcontext.ss.r12),
+ 13 => mem.asBytes(&ucontext_ptr.mcontext.ss.r13),
+ 14 => mem.asBytes(&ucontext_ptr.mcontext.ss.r14),
+ 15 => mem.asBytes(&ucontext_ptr.mcontext.ss.r15),
+ 16 => mem.asBytes(&ucontext_ptr.mcontext.ss.rip),
+ else => error.InvalidRegister,
+ },
+ else => error.UnimplementedOs,
+ },
+ .arm => switch (builtin.os.tag) {
+ .linux => switch (reg_number) {
+ 0 => mem.asBytes(&ucontext_ptr.mcontext.arm_r0),
+ 1 => mem.asBytes(&ucontext_ptr.mcontext.arm_r1),
+ 2 => mem.asBytes(&ucontext_ptr.mcontext.arm_r2),
+ 3 => mem.asBytes(&ucontext_ptr.mcontext.arm_r3),
+ 4 => mem.asBytes(&ucontext_ptr.mcontext.arm_r4),
+ 5 => mem.asBytes(&ucontext_ptr.mcontext.arm_r5),
+ 6 => mem.asBytes(&ucontext_ptr.mcontext.arm_r6),
+ 7 => mem.asBytes(&ucontext_ptr.mcontext.arm_r7),
+ 8 => mem.asBytes(&ucontext_ptr.mcontext.arm_r8),
+ 9 => mem.asBytes(&ucontext_ptr.mcontext.arm_r9),
+ 10 => mem.asBytes(&ucontext_ptr.mcontext.arm_r10),
+ 11 => mem.asBytes(&ucontext_ptr.mcontext.arm_fp),
+ 12 => mem.asBytes(&ucontext_ptr.mcontext.arm_ip),
+ 13 => mem.asBytes(&ucontext_ptr.mcontext.arm_sp),
+ 14 => mem.asBytes(&ucontext_ptr.mcontext.arm_lr),
+ 15 => mem.asBytes(&ucontext_ptr.mcontext.arm_pc),
+ // CPSR is not allocated a register number (See: https://github.com/ARM-software/abi-aa/blob/main/aadwarf32/aadwarf32.rst, Section 4.1)
+ else => error.InvalidRegister,
+ },
+ else => error.UnimplementedOs,
+ },
+ .aarch64 => switch (builtin.os.tag) {
+ .macos => switch (reg_number) {
+ 0...28 => mem.asBytes(&ucontext_ptr.mcontext.ss.regs[reg_number]),
+ 29 => mem.asBytes(&ucontext_ptr.mcontext.ss.fp),
+ 30 => mem.asBytes(&ucontext_ptr.mcontext.ss.lr),
+ 31 => mem.asBytes(&ucontext_ptr.mcontext.ss.sp),
+ 32 => mem.asBytes(&ucontext_ptr.mcontext.ss.pc),
+
+ // TODO: Find storage for this state
+ //34 => mem.asBytes(&ucontext_ptr.ra_sign_state),
+
+ // V0-V31
+ 64...95 => mem.asBytes(&ucontext_ptr.mcontext.ns.q[reg_number - 64]),
+ else => error.InvalidRegister,
+ },
+ .netbsd => switch (reg_number) {
+ 0...34 => mem.asBytes(&ucontext_ptr.mcontext.gregs[reg_number]),
+ else => error.InvalidRegister,
+ },
+ .freebsd => switch (reg_number) {
+ 0...29 => mem.asBytes(&ucontext_ptr.mcontext.gpregs.x[reg_number]),
+ 30 => mem.asBytes(&ucontext_ptr.mcontext.gpregs.lr),
+ 31 => mem.asBytes(&ucontext_ptr.mcontext.gpregs.sp),
+
+ // TODO: This seems wrong, but it was in the previous debug.zig code for mapping PC, check this
+ 32 => mem.asBytes(&ucontext_ptr.mcontext.gpregs.elr),
+
+ else => error.InvalidRegister,
+ },
+ else => switch (reg_number) {
+ 0...30 => mem.asBytes(&ucontext_ptr.mcontext.regs[reg_number]),
+ 31 => mem.asBytes(&ucontext_ptr.mcontext.sp),
+ 32 => mem.asBytes(&ucontext_ptr.mcontext.pc),
+ else => error.InvalidRegister,
+ },
+ },
+ else => error.UnimplementedArch,
+ };
+}
+
+/// Returns the ABI-defined default value this register has in the unwinding table
+/// before running any of the CIE instructions. The DWARF spec defines these as having
+/// the .undefined rule by default, but allows ABI authors to override that.
+pub fn getRegDefaultValue(reg_number: u8, context: *std.dwarf.UnwindContext, out: []u8) !void {
+ switch (builtin.cpu.arch) {
+ .aarch64 => {
+ // Callee-saved registers are initialized as if they had the .same_value rule
+ if (reg_number >= 19 and reg_number <= 28) {
+ const src = try regBytes(context.thread_context, reg_number, context.reg_context);
+ if (src.len != out.len) return error.RegisterSizeMismatch;
+ @memcpy(out, src);
+ return;
+ }
+ },
+ else => {},
+ }
+
+ @memset(out, undefined);
+}
diff --git a/lib/std/dwarf/call_frame.zig b/lib/std/dwarf/call_frame.zig
@@ -0,0 +1,610 @@
+const builtin = @import("builtin");
+const std = @import("../std.zig");
+const mem = std.mem;
+const debug = std.debug;
+const leb = std.leb;
+const dwarf = std.dwarf;
+const abi = dwarf.abi;
+const expressions = dwarf.expressions;
+const assert = std.debug.assert;
+
+const Opcode = enum(u8) {
+ advance_loc = 0x1 << 6,
+ offset = 0x2 << 6,
+ restore = 0x3 << 6,
+
+ nop = 0x00,
+ set_loc = 0x01,
+ advance_loc1 = 0x02,
+ advance_loc2 = 0x03,
+ advance_loc4 = 0x04,
+ offset_extended = 0x05,
+ restore_extended = 0x06,
+ undefined = 0x07,
+ same_value = 0x08,
+ register = 0x09,
+ remember_state = 0x0a,
+ restore_state = 0x0b,
+ def_cfa = 0x0c,
+ def_cfa_register = 0x0d,
+ def_cfa_offset = 0x0e,
+ def_cfa_expression = 0x0f,
+ expression = 0x10,
+ offset_extended_sf = 0x11,
+ def_cfa_sf = 0x12,
+ def_cfa_offset_sf = 0x13,
+ val_offset = 0x14,
+ val_offset_sf = 0x15,
+ val_expression = 0x16,
+
+ // These opcodes encode an operand in the lower 6 bits of the opcode itself
+ pub const lo_inline = @intFromEnum(Opcode.advance_loc);
+ pub const hi_inline = @intFromEnum(Opcode.restore) | 0b111111;
+
+ // These opcodes are trailed by zero or more operands
+ pub const lo_reserved = @intFromEnum(Opcode.nop);
+ pub const hi_reserved = @intFromEnum(Opcode.val_expression);
+
+ // Vendor-specific opcodes
+ pub const lo_user = 0x1c;
+ pub const hi_user = 0x3f;
+};
+
+const Operand = enum {
+ opcode_delta,
+ opcode_register,
+ uleb128_register,
+ uleb128_offset,
+ sleb128_offset,
+ address,
+ u8_delta,
+ u16_delta,
+ u32_delta,
+ block,
+
+ fn Storage(comptime self: Operand) type {
+ return switch (self) {
+ .opcode_delta, .opcode_register => u8,
+ .uleb128_register => u8,
+ .uleb128_offset => u64,
+ .sleb128_offset => i64,
+ .address => u64,
+ .u8_delta => u8,
+ .u16_delta => u16,
+ .u32_delta => u32,
+ .block => []const u8,
+ };
+ }
+
+ fn read(
+ comptime self: Operand,
+ stream: *std.io.FixedBufferStream([]const u8),
+ opcode_value: ?u6,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !Storage(self) {
+ const reader = stream.reader();
+ return switch (self) {
+ .opcode_delta, .opcode_register => opcode_value orelse return error.InvalidOperand,
+ .uleb128_register => try leb.readULEB128(u8, reader),
+ .uleb128_offset => try leb.readULEB128(u64, reader),
+ .sleb128_offset => try leb.readILEB128(i64, reader),
+ .address => switch (addr_size_bytes) {
+ 2 => try reader.readInt(u16, endian),
+ 4 => try reader.readInt(u32, endian),
+ 8 => try reader.readInt(u64, endian),
+ else => return error.InvalidAddrSize,
+ },
+ .u8_delta => try reader.readByte(),
+ .u16_delta => try reader.readInt(u16, endian),
+ .u32_delta => try reader.readInt(u32, endian),
+ .block => {
+ const block_len = try leb.readULEB128(usize, reader);
+ if (stream.pos + block_len > stream.buffer.len) return error.InvalidOperand;
+
+ const block = stream.buffer[stream.pos..][0..block_len];
+ reader.context.pos += block_len;
+
+ return block;
+ },
+ };
+ }
+};
+
+fn InstructionType(comptime definition: anytype) type {
+ const definition_type = @typeInfo(@TypeOf(definition));
+ assert(definition_type == .Struct);
+
+ const definition_len = definition_type.Struct.fields.len;
+ comptime var fields: [definition_len]std.builtin.Type.StructField = undefined;
+ inline for (definition_type.Struct.fields, &fields) |definition_field, *operands_field| {
+ const opcode = std.enums.nameCast(Operand, @field(definition, definition_field.name));
+ const storage_type = opcode.Storage();
+ operands_field.* = .{
+ .name = definition_field.name,
+ .type = storage_type,
+ .default_value = null,
+ .is_comptime = false,
+ .alignment = @alignOf(storage_type),
+ };
+ }
+
+ const InstructionOperands = @Type(.{
+ .Struct = .{
+ .layout = .Auto,
+ .fields = &fields,
+ .decls = &.{},
+ .is_tuple = false,
+ },
+ });
+
+ return struct {
+ const Self = @This();
+ operands: InstructionOperands,
+
+ pub fn read(
+ stream: *std.io.FixedBufferStream([]const u8),
+ opcode_value: ?u6,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !Self {
+ var operands: InstructionOperands = undefined;
+ inline for (definition_type.Struct.fields) |definition_field| {
+ const operand = comptime std.enums.nameCast(Operand, @field(definition, definition_field.name));
+ @field(operands, definition_field.name) = try operand.read(stream, opcode_value, addr_size_bytes, endian);
+ }
+
+ return .{ .operands = operands };
+ }
+ };
+}
+
+pub const Instruction = union(Opcode) {
+ advance_loc: InstructionType(.{ .delta = .opcode_delta }),
+ offset: InstructionType(.{ .register = .opcode_register, .offset = .uleb128_offset }),
+ offset_extended: InstructionType(.{ .register = .uleb128_register, .offset = .uleb128_offset }),
+ restore: InstructionType(.{ .register = .opcode_register }),
+ restore_extended: InstructionType(.{ .register = .uleb128_register }),
+ nop: InstructionType(.{}),
+ set_loc: InstructionType(.{ .address = .address }),
+ advance_loc1: InstructionType(.{ .delta = .u8_delta }),
+ advance_loc2: InstructionType(.{ .delta = .u16_delta }),
+ advance_loc4: InstructionType(.{ .delta = .u32_delta }),
+ undefined: InstructionType(.{ .register = .uleb128_register }),
+ same_value: InstructionType(.{ .register = .uleb128_register }),
+ register: InstructionType(.{ .register = .uleb128_register, .target_register = .uleb128_register }),
+ remember_state: InstructionType(.{}),
+ restore_state: InstructionType(.{}),
+ def_cfa: InstructionType(.{ .register = .uleb128_register, .offset = .uleb128_offset }),
+ def_cfa_register: InstructionType(.{ .register = .uleb128_register }),
+ def_cfa_offset: InstructionType(.{ .offset = .uleb128_offset }),
+ def_cfa_expression: InstructionType(.{ .block = .block }),
+ expression: InstructionType(.{ .register = .uleb128_register, .block = .block }),
+ offset_extended_sf: InstructionType(.{ .register = .uleb128_register, .offset = .sleb128_offset }),
+ def_cfa_sf: InstructionType(.{ .register = .uleb128_register, .offset = .sleb128_offset }),
+ def_cfa_offset_sf: InstructionType(.{ .offset = .sleb128_offset }),
+ val_offset: InstructionType(.{ .register = .uleb128_register, .offset = .uleb128_offset }),
+ val_offset_sf: InstructionType(.{ .register = .uleb128_register, .offset = .sleb128_offset }),
+ val_expression: InstructionType(.{ .register = .uleb128_register, .block = .block }),
+
+ fn readOperands(
+ self: *Instruction,
+ stream: *std.io.FixedBufferStream([]const u8),
+ opcode_value: ?u6,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !void {
+ switch (self.*) {
+ inline else => |*inst| inst.* = try @TypeOf(inst.*).read(stream, opcode_value, addr_size_bytes, endian),
+ }
+ }
+
+ pub fn read(
+ stream: *std.io.FixedBufferStream([]const u8),
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !Instruction {
+ return switch (try stream.reader().readByte()) {
+ inline Opcode.lo_inline...Opcode.hi_inline => |opcode| blk: {
+ const e: Opcode = @enumFromInt(opcode & 0b11000000);
+ var result = @unionInit(Instruction, @tagName(e), undefined);
+ try result.readOperands(stream, @as(u6, @intCast(opcode & 0b111111)), addr_size_bytes, endian);
+ break :blk result;
+ },
+ inline Opcode.lo_reserved...Opcode.hi_reserved => |opcode| blk: {
+ const e: Opcode = @enumFromInt(opcode);
+ var result = @unionInit(Instruction, @tagName(e), undefined);
+ try result.readOperands(stream, null, addr_size_bytes, endian);
+ break :blk result;
+ },
+ Opcode.lo_user...Opcode.hi_user => error.UnimplementedUserOpcode,
+ else => error.InvalidOpcode,
+ };
+ }
+};
+
+/// Since register rules are applied (usually) during a panic,
+/// checked addition / subtraction is used so that we can return
+/// an error and fall back to FP-based unwinding.
+pub fn applyOffset(base: usize, offset: i64) !usize {
+ return if (offset >= 0)
+ try std.math.add(usize, base, @as(usize, @intCast(offset)))
+ else
+ try std.math.sub(usize, base, @as(usize, @intCast(-offset)));
+}
+
+/// This is a virtual machine that runs DWARF call frame instructions.
+pub const VirtualMachine = struct {
+ /// See section 6.4.1 of the DWARF5 specification for details on each
+ const RegisterRule = union(enum) {
+ // The spec says that the default rule for each column is the undefined rule.
+ // However, it also allows ABI / compiler authors to specify alternate defaults, so
+ // there is a distinction made here.
+ default: void,
+
+ undefined: void,
+ same_value: void,
+
+ // offset(N)
+ offset: i64,
+
+ // val_offset(N)
+ val_offset: i64,
+
+ // register(R)
+ register: u8,
+
+ // expression(E)
+ expression: []const u8,
+
+ // val_expression(E)
+ val_expression: []const u8,
+
+ // Augmenter-defined rule
+ architectural: void,
+ };
+
+ /// Each row contains unwinding rules for a set of registers.
+ pub const Row = struct {
+ /// Offset from `FrameDescriptionEntry.pc_begin`
+ offset: u64 = 0,
+
+ /// Special-case column that defines the CFA (Canonical Frame Address) rule.
+ /// The register field of this column defines the register that CFA is derived from.
+ cfa: Column = .{},
+
+ /// The register fields in these columns define the register the rule applies to.
+ columns: ColumnRange = .{},
+
+ /// Indicates that the next write to any column in this row needs to copy
+ /// the backing column storage first, as it may be referenced by previous rows.
+ copy_on_write: bool = false,
+ };
+
+ pub const Column = struct {
+ register: ?u8 = null,
+ rule: RegisterRule = .{ .default = {} },
+
+ /// Resolves the register rule and places the result into `out` (see dwarf.abi.regBytes)
+ pub fn resolveValue(
+ self: Column,
+ context: *dwarf.UnwindContext,
+ expression_context: dwarf.expressions.ExpressionContext,
+ out: []u8,
+ ) !void {
+ switch (self.rule) {
+ .default => {
+ const register = self.register orelse return error.InvalidRegister;
+ try abi.getRegDefaultValue(register, context, out);
+ },
+ .undefined => {
+ @memset(out, undefined);
+ },
+ .same_value => {
+ // TODO: This copy could be eliminated if callers always copy the state then call this function to update it
+ const register = self.register orelse return error.InvalidRegister;
+ const src = try abi.regBytes(context.thread_context, register, context.reg_context);
+ if (src.len != out.len) return error.RegisterSizeMismatch;
+ @memcpy(out, src);
+ },
+ .offset => |offset| {
+ if (context.cfa) |cfa| {
+ const addr = try applyOffset(cfa, offset);
+ if (expression_context.isValidMemory) |isValidMemory| if (!isValidMemory(addr)) return error.InvalidAddress;
+ const ptr: *const usize = @ptrFromInt(addr);
+ mem.writeIntSliceNative(usize, out, ptr.*);
+ } else return error.InvalidCFA;
+ },
+ .val_offset => |offset| {
+ if (context.cfa) |cfa| {
+ mem.writeIntSliceNative(usize, out, try applyOffset(cfa, offset));
+ } else return error.InvalidCFA;
+ },
+ .register => |register| {
+ const src = try abi.regBytes(context.thread_context, register, context.reg_context);
+ if (src.len != out.len) return error.RegisterSizeMismatch;
+ @memcpy(out, try abi.regBytes(context.thread_context, register, context.reg_context));
+ },
+ .expression => |expression| {
+ context.stack_machine.reset();
+ const value = try context.stack_machine.run(expression, context.allocator, expression_context, context.cfa.?);
+ const addr = if (value) |v| blk: {
+ if (v != .generic) return error.InvalidExpressionValue;
+ break :blk v.generic;
+ } else return error.NoExpressionValue;
+
+ if (!context.isValidMemory(addr)) return error.InvalidExpressionAddress;
+ const ptr: *usize = @ptrFromInt(addr);
+ mem.writeIntSliceNative(usize, out, ptr.*);
+ },
+ .val_expression => |expression| {
+ context.stack_machine.reset();
+ const value = try context.stack_machine.run(expression, context.allocator, expression_context, context.cfa.?);
+ if (value) |v| {
+ if (v != .generic) return error.InvalidExpressionValue;
+ mem.writeIntSliceNative(usize, out, v.generic);
+ } else return error.NoExpressionValue;
+ },
+ .architectural => return error.UnimplementedRegisterRule,
+ }
+ }
+ };
+
+ const ColumnRange = struct {
+ /// Index into `columns` of the first column in this row.
+ start: usize = undefined,
+ len: u8 = 0,
+ };
+
+ columns: std.ArrayListUnmanaged(Column) = .{},
+ stack: std.ArrayListUnmanaged(ColumnRange) = .{},
+ current_row: Row = .{},
+
+ /// The result of executing the CIE's initial_instructions
+ cie_row: ?Row = null,
+
+ pub fn deinit(self: *VirtualMachine, allocator: std.mem.Allocator) void {
+ self.stack.deinit(allocator);
+ self.columns.deinit(allocator);
+ self.* = undefined;
+ }
+
+ pub fn reset(self: *VirtualMachine) void {
+ self.stack.clearRetainingCapacity();
+ self.columns.clearRetainingCapacity();
+ self.current_row = .{};
+ self.cie_row = null;
+ }
+
+ /// Return a slice backed by the row's non-CFA columns
+ pub fn rowColumns(self: VirtualMachine, row: Row) []Column {
+ return self.columns.items[row.columns.start..][0..row.columns.len];
+ }
+
+ /// Either retrieves or adds a column for `register` (non-CFA) in the current row.
+ fn getOrAddColumn(self: *VirtualMachine, allocator: std.mem.Allocator, register: u8) !*Column {
+ for (self.rowColumns(self.current_row)) |*c| {
+ if (c.register == register) return c;
+ }
+
+ if (self.current_row.columns.len == 0) {
+ self.current_row.columns.start = self.columns.items.len;
+ }
+ self.current_row.columns.len += 1;
+
+ const column = try self.columns.addOne(allocator);
+ column.* = .{
+ .register = register,
+ };
+
+ return column;
+ }
+
+ /// Runs the CIE instructions, then the FDE instructions. Execution halts
+ /// once the row that corresponds to `pc` is known, and the row is returned.
+ pub fn runTo(
+ self: *VirtualMachine,
+ allocator: std.mem.Allocator,
+ pc: u64,
+ cie: dwarf.CommonInformationEntry,
+ fde: dwarf.FrameDescriptionEntry,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !Row {
+ assert(self.cie_row == null);
+ if (pc < fde.pc_begin or pc >= fde.pc_begin + fde.pc_range) return error.AddressOutOfRange;
+
+ var prev_row: Row = self.current_row;
+
+ var cie_stream = std.io.fixedBufferStream(cie.initial_instructions);
+ var fde_stream = std.io.fixedBufferStream(fde.instructions);
+ var streams = [_]*std.io.FixedBufferStream([]const u8){
+ &cie_stream,
+ &fde_stream,
+ };
+
+ for (&streams, 0..) |stream, i| {
+ while (stream.pos < stream.buffer.len) {
+ const instruction = try dwarf.call_frame.Instruction.read(stream, addr_size_bytes, endian);
+ prev_row = try self.step(allocator, cie, i == 0, instruction);
+ if (pc < fde.pc_begin + self.current_row.offset) return prev_row;
+ }
+ }
+
+ return self.current_row;
+ }
+
+ pub fn runToNative(
+ self: *VirtualMachine,
+ allocator: std.mem.Allocator,
+ pc: u64,
+ cie: dwarf.CommonInformationEntry,
+ fde: dwarf.FrameDescriptionEntry,
+ ) !Row {
+ return self.runTo(allocator, pc, cie, fde, @sizeOf(usize), builtin.target.cpu.arch.endian());
+ }
+
+ fn resolveCopyOnWrite(self: *VirtualMachine, allocator: std.mem.Allocator) !void {
+ if (!self.current_row.copy_on_write) return;
+
+ const new_start = self.columns.items.len;
+ if (self.current_row.columns.len > 0) {
+ try self.columns.ensureUnusedCapacity(allocator, self.current_row.columns.len);
+ self.columns.appendSliceAssumeCapacity(self.rowColumns(self.current_row));
+ self.current_row.columns.start = new_start;
+ }
+ }
+
+ /// Executes a single instruction.
+ /// If this instruction is from the CIE, `is_initial` should be set.
+ /// Returns the value of `current_row` before executing this instruction.
+ pub fn step(
+ self: *VirtualMachine,
+ allocator: std.mem.Allocator,
+ cie: dwarf.CommonInformationEntry,
+ is_initial: bool,
+ instruction: Instruction,
+ ) !Row {
+ // CIE instructions must be run before FDE instructions
+ assert(!is_initial or self.cie_row == null);
+ if (!is_initial and self.cie_row == null) {
+ self.cie_row = self.current_row;
+ self.current_row.copy_on_write = true;
+ }
+
+ const prev_row = self.current_row;
+ switch (instruction) {
+ .set_loc => |i| {
+ if (i.operands.address <= self.current_row.offset) return error.InvalidOperation;
+ // TODO: Check cie.segment_selector_size != 0 for DWARFV4
+ self.current_row.offset = i.operands.address;
+ },
+ inline .advance_loc,
+ .advance_loc1,
+ .advance_loc2,
+ .advance_loc4,
+ => |i| {
+ self.current_row.offset += i.operands.delta * cie.code_alignment_factor;
+ self.current_row.copy_on_write = true;
+ },
+ inline .offset,
+ .offset_extended,
+ .offset_extended_sf,
+ => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{ .offset = @as(i64, @intCast(i.operands.offset)) * cie.data_alignment_factor };
+ },
+ inline .restore,
+ .restore_extended,
+ => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ if (self.cie_row) |cie_row| {
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = for (self.rowColumns(cie_row)) |cie_column| {
+ if (cie_column.register == i.operands.register) break cie_column.rule;
+ } else .{ .default = {} };
+ } else return error.InvalidOperation;
+ },
+ .nop => {},
+ .undefined => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{ .undefined = {} };
+ },
+ .same_value => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{ .same_value = {} };
+ },
+ .register => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{ .register = i.operands.target_register };
+ },
+ .remember_state => {
+ try self.stack.append(allocator, self.current_row.columns);
+ self.current_row.copy_on_write = true;
+ },
+ .restore_state => {
+ const restored_columns = self.stack.popOrNull() orelse return error.InvalidOperation;
+ self.columns.shrinkRetainingCapacity(self.columns.items.len - self.current_row.columns.len);
+ try self.columns.ensureUnusedCapacity(allocator, restored_columns.len);
+
+ self.current_row.columns.start = self.columns.items.len;
+ self.current_row.columns.len = restored_columns.len;
+ self.columns.appendSliceAssumeCapacity(self.columns.items[restored_columns.start..][0..restored_columns.len]);
+ },
+ .def_cfa => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ self.current_row.cfa = .{
+ .register = i.operands.register,
+ .rule = .{ .val_offset = @intCast(i.operands.offset) },
+ };
+ },
+ .def_cfa_sf => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ self.current_row.cfa = .{
+ .register = i.operands.register,
+ .rule = .{ .val_offset = i.operands.offset * cie.data_alignment_factor },
+ };
+ },
+ .def_cfa_register => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
+ self.current_row.cfa.register = i.operands.register;
+ },
+ .def_cfa_offset => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
+ self.current_row.cfa.rule = .{
+ .val_offset = @intCast(i.operands.offset),
+ };
+ },
+ .def_cfa_offset_sf => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ if (self.current_row.cfa.register == null or self.current_row.cfa.rule != .val_offset) return error.InvalidOperation;
+ self.current_row.cfa.rule = .{
+ .val_offset = i.operands.offset * cie.data_alignment_factor,
+ };
+ },
+ .def_cfa_expression => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ self.current_row.cfa.register = undefined;
+ self.current_row.cfa.rule = .{
+ .expression = i.operands.block,
+ };
+ },
+ .expression => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{
+ .expression = i.operands.block,
+ };
+ },
+ .val_offset => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{
+ .val_offset = @as(i64, @intCast(i.operands.offset)) * cie.data_alignment_factor,
+ };
+ },
+ .val_offset_sf => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{
+ .val_offset = i.operands.offset * cie.data_alignment_factor,
+ };
+ },
+ .val_expression => |i| {
+ try self.resolveCopyOnWrite(allocator);
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = .{
+ .val_expression = i.operands.block,
+ };
+ },
+ }
+
+ return prev_row;
+ }
+};
diff --git a/lib/std/dwarf/expressions.zig b/lib/std/dwarf/expressions.zig
@@ -0,0 +1,1639 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const OP = @import("OP.zig");
+const leb = std.leb;
+const dwarf = std.dwarf;
+const abi = dwarf.abi;
+const mem = std.mem;
+const assert = std.debug.assert;
+
+/// Expressions can be evaluated in different contexts, each requiring its own set of inputs.
+/// Callers should specify all the fields relevant to their context. If a field is required
+/// by the expression and it isn't in the context, error.IncompleteExpressionContext is returned.
+pub const ExpressionContext = struct {
+ /// This expression is from a DWARF64 section
+ is_64: bool = false,
+
+ /// If specified, any addresses will pass through this function before being acccessed
+ isValidMemory: ?*const fn (address: usize) bool = null,
+
+ /// The compilation unit this expression relates to, if any
+ compile_unit: ?*const dwarf.CompileUnit = null,
+
+ /// When evaluating a user-presented expression, this is the address of the object being evaluated
+ object_address: ?*const anyopaque = null,
+
+ /// .debug_addr section
+ debug_addr: ?[]const u8 = null,
+
+ /// Thread context
+ thread_context: ?*std.debug.ThreadContext = null,
+ reg_context: ?abi.RegisterContext = null,
+
+ /// Call frame address, if in a CFI context
+ cfa: ?usize = null,
+
+ /// This expression is a sub-expression from an OP.entry_value instruction
+ entry_value_context: bool = false,
+};
+
+pub const ExpressionOptions = struct {
+ /// The address size of the target architecture
+ addr_size: u8 = @sizeOf(usize),
+
+ /// Endianess of the target architecture
+ endian: std.builtin.Endian = builtin.target.cpu.arch.endian(),
+
+ /// Restrict the stack machine to a subset of opcodes used in call frame instructions
+ call_frame_context: bool = false,
+};
+
+// Explcitly defined to support executing sub-expressions
+pub const ExpressionError = error{
+ UnimplementedExpressionCall,
+ UnimplementedOpcode,
+ UnimplementedUserOpcode,
+ UnimplementedTypedComparison,
+ UnimplementedTypeConversion,
+
+ UnknownExpressionOpcode,
+
+ IncompleteExpressionContext,
+
+ InvalidCFAOpcode,
+ InvalidExpression,
+ InvalidFrameBase,
+ InvalidIntegralTypeSize,
+ InvalidRegister,
+ InvalidSubExpression,
+ InvalidTypeLength,
+
+ TruncatedIntegralType,
+} || abi.AbiError || error{ EndOfStream, Overflow, OutOfMemory, DivisionByZero };
+
+/// A stack machine that can decode and run DWARF expressions.
+/// Expressions can be decoded for non-native address size and endianness,
+/// but can only be executed if the current target matches the configuration.
+pub fn StackMachine(comptime options: ExpressionOptions) type {
+ const addr_type = switch (options.addr_size) {
+ 2 => u16,
+ 4 => u32,
+ 8 => u64,
+ else => @compileError("Unsupported address size of " ++ options.addr_size),
+ };
+
+ const addr_type_signed = switch (options.addr_size) {
+ 2 => i16,
+ 4 => i32,
+ 8 => i64,
+ else => @compileError("Unsupported address size of " ++ options.addr_size),
+ };
+
+ return struct {
+ const Self = @This();
+
+ const Operand = union(enum) {
+ generic: addr_type,
+ register: u8,
+ type_size: u8,
+ branch_offset: i16,
+ base_register: struct {
+ base_register: u8,
+ offset: i64,
+ },
+ composite_location: struct {
+ size: u64,
+ offset: i64,
+ },
+ block: []const u8,
+ register_type: struct {
+ register: u8,
+ type_offset: addr_type,
+ },
+ const_type: struct {
+ type_offset: addr_type,
+ value_bytes: []const u8,
+ },
+ deref_type: struct {
+ size: u8,
+ type_offset: addr_type,
+ },
+ };
+
+ const Value = union(enum) {
+ generic: addr_type,
+
+ // Typed value with a maximum size of a register
+ regval_type: struct {
+ // Offset of DW_TAG_base_type DIE
+ type_offset: addr_type,
+ type_size: u8,
+ value: addr_type,
+ },
+
+ // Typed value specified directly in the instruction stream
+ const_type: struct {
+ // Offset of DW_TAG_base_type DIE
+ type_offset: addr_type,
+ // Backed by the instruction stream
+ value_bytes: []const u8,
+ },
+
+ pub fn asIntegral(self: Value) !addr_type {
+ return switch (self) {
+ .generic => |v| v,
+
+ // TODO: For these two prongs, look up the type and assert it's integral?
+ .regval_type => |regval_type| regval_type.value,
+ .const_type => |const_type| {
+ const value: u64 = switch (const_type.value_bytes.len) {
+ 1 => mem.readIntSliceNative(u8, const_type.value_bytes),
+ 2 => mem.readIntSliceNative(u16, const_type.value_bytes),
+ 4 => mem.readIntSliceNative(u32, const_type.value_bytes),
+ 8 => mem.readIntSliceNative(u64, const_type.value_bytes),
+ else => return error.InvalidIntegralTypeSize,
+ };
+
+ return std.math.cast(addr_type, value) orelse error.TruncatedIntegralType;
+ },
+ };
+ }
+ };
+
+ stack: std.ArrayListUnmanaged(Value) = .{},
+
+ pub fn reset(self: *Self) void {
+ self.stack.clearRetainingCapacity();
+ }
+
+ pub fn deinit(self: *Self, allocator: std.mem.Allocator) void {
+ self.stack.deinit(allocator);
+ }
+
+ fn generic(value: anytype) Operand {
+ const int_info = @typeInfo(@TypeOf(value)).Int;
+ if (@sizeOf(@TypeOf(value)) > options.addr_size) {
+ return .{ .generic = switch (int_info.signedness) {
+ .signed => @bitCast(@as(addr_type_signed, @truncate(value))),
+ .unsigned => @truncate(value),
+ } };
+ } else {
+ return .{ .generic = switch (int_info.signedness) {
+ .signed => @bitCast(@as(addr_type_signed, @intCast(value))),
+ .unsigned => @intCast(value),
+ } };
+ }
+ }
+
+ pub fn readOperand(stream: *std.io.FixedBufferStream([]const u8), opcode: u8, context: ExpressionContext) !?Operand {
+ const reader = stream.reader();
+ return switch (opcode) {
+ OP.addr => generic(try reader.readInt(addr_type, options.endian)),
+ OP.call_ref => if (context.is_64)
+ generic(try reader.readInt(u64, options.endian))
+ else
+ generic(try reader.readInt(u32, options.endian)),
+ OP.const1u,
+ OP.pick,
+ => generic(try reader.readByte()),
+ OP.deref_size,
+ OP.xderef_size,
+ => .{ .type_size = try reader.readByte() },
+ OP.const1s => generic(try reader.readByteSigned()),
+ OP.const2u,
+ OP.call2,
+ => generic(try reader.readInt(u16, options.endian)),
+ OP.call4 => generic(try reader.readInt(u32, options.endian)),
+ OP.const2s => generic(try reader.readInt(i16, options.endian)),
+ OP.bra,
+ OP.skip,
+ => .{ .branch_offset = try reader.readInt(i16, options.endian) },
+ OP.const4u => generic(try reader.readInt(u32, options.endian)),
+ OP.const4s => generic(try reader.readInt(i32, options.endian)),
+ OP.const8u => generic(try reader.readInt(u64, options.endian)),
+ OP.const8s => generic(try reader.readInt(i64, options.endian)),
+ OP.constu,
+ OP.plus_uconst,
+ OP.addrx,
+ OP.constx,
+ OP.convert,
+ OP.reinterpret,
+ => generic(try leb.readULEB128(u64, reader)),
+ OP.consts,
+ OP.fbreg,
+ => generic(try leb.readILEB128(i64, reader)),
+ OP.lit0...OP.lit31 => |n| generic(n - OP.lit0),
+ OP.reg0...OP.reg31 => |n| .{ .register = n - OP.reg0 },
+ OP.breg0...OP.breg31 => |n| .{ .base_register = .{
+ .base_register = n - OP.breg0,
+ .offset = try leb.readILEB128(i64, reader),
+ } },
+ OP.regx => .{ .register = try leb.readULEB128(u8, reader) },
+ OP.bregx => blk: {
+ const base_register = try leb.readULEB128(u8, reader);
+ const offset = try leb.readILEB128(i64, reader);
+ break :blk .{ .base_register = .{
+ .base_register = base_register,
+ .offset = offset,
+ } };
+ },
+ OP.regval_type => blk: {
+ const register = try leb.readULEB128(u8, reader);
+ const type_offset = try leb.readULEB128(addr_type, reader);
+ break :blk .{ .register_type = .{
+ .register = register,
+ .type_offset = type_offset,
+ } };
+ },
+ OP.piece => .{
+ .composite_location = .{
+ .size = try leb.readULEB128(u8, reader),
+ .offset = 0,
+ },
+ },
+ OP.bit_piece => blk: {
+ const size = try leb.readULEB128(u8, reader);
+ const offset = try leb.readILEB128(i64, reader);
+ break :blk .{ .composite_location = .{
+ .size = size,
+ .offset = offset,
+ } };
+ },
+ OP.implicit_value, OP.entry_value => blk: {
+ const size = try leb.readULEB128(u8, reader);
+ if (stream.pos + size > stream.buffer.len) return error.InvalidExpression;
+ const block = stream.buffer[stream.pos..][0..size];
+ stream.pos += size;
+ break :blk .{
+ .block = block,
+ };
+ },
+ OP.const_type => blk: {
+ const type_offset = try leb.readULEB128(addr_type, reader);
+ const size = try reader.readByte();
+ if (stream.pos + size > stream.buffer.len) return error.InvalidExpression;
+ const value_bytes = stream.buffer[stream.pos..][0..size];
+ stream.pos += size;
+ break :blk .{ .const_type = .{
+ .type_offset = type_offset,
+ .value_bytes = value_bytes,
+ } };
+ },
+ OP.deref_type,
+ OP.xderef_type,
+ => .{
+ .deref_type = .{
+ .size = try reader.readByte(),
+ .type_offset = try leb.readULEB128(addr_type, reader),
+ },
+ },
+ OP.lo_user...OP.hi_user => return error.UnimplementedUserOpcode,
+ else => null,
+ };
+ }
+
+ pub fn run(
+ self: *Self,
+ expression: []const u8,
+ allocator: std.mem.Allocator,
+ context: ExpressionContext,
+ initial_value: ?usize,
+ ) ExpressionError!?Value {
+ if (initial_value) |i| try self.stack.append(allocator, .{ .generic = i });
+ var stream = std.io.fixedBufferStream(expression);
+ while (try self.step(&stream, allocator, context)) {}
+ if (self.stack.items.len == 0) return null;
+ return self.stack.items[self.stack.items.len - 1];
+ }
+
+ /// Reads an opcode and its operands from `stream`, then executes it
+ pub fn step(
+ self: *Self,
+ stream: *std.io.FixedBufferStream([]const u8),
+ allocator: std.mem.Allocator,
+ context: ExpressionContext,
+ ) ExpressionError!bool {
+ if (@sizeOf(usize) != @sizeOf(addr_type) or options.endian != comptime builtin.target.cpu.arch.endian())
+ @compileError("Execution of non-native address sizes / endianness is not supported");
+
+ const opcode = try stream.reader().readByte();
+ if (options.call_frame_context and !isOpcodeValidInCFA(opcode)) return error.InvalidCFAOpcode;
+ switch (opcode) {
+
+ // 2.5.1.1: Literal Encodings
+ OP.lit0...OP.lit31,
+ OP.addr,
+ OP.const1u,
+ OP.const2u,
+ OP.const4u,
+ OP.const8u,
+ OP.const1s,
+ OP.const2s,
+ OP.const4s,
+ OP.const8s,
+ OP.constu,
+ OP.consts,
+ => try self.stack.append(allocator, .{ .generic = (try readOperand(stream, opcode, context)).?.generic }),
+
+ OP.const_type => {
+ const const_type = (try readOperand(stream, opcode, context)).?.const_type;
+ try self.stack.append(allocator, .{ .const_type = .{
+ .type_offset = const_type.type_offset,
+ .value_bytes = const_type.value_bytes,
+ } });
+ },
+
+ OP.addrx,
+ OP.constx,
+ => {
+ if (context.compile_unit == null) return error.IncompleteExpressionContext;
+ if (context.debug_addr == null) return error.IncompleteExpressionContext;
+ const debug_addr_index = (try readOperand(stream, opcode, context)).?.generic;
+ const offset = context.compile_unit.?.addr_base + debug_addr_index;
+ if (offset >= context.debug_addr.?.len) return error.InvalidExpression;
+ const value = mem.readIntSliceNative(usize, context.debug_addr.?[offset..][0..@sizeOf(usize)]);
+ try self.stack.append(allocator, .{ .generic = value });
+ },
+
+ // 2.5.1.2: Register Values
+ OP.fbreg => {
+ if (context.compile_unit == null) return error.IncompleteExpressionContext;
+ if (context.compile_unit.?.frame_base == null) return error.IncompleteExpressionContext;
+
+ const offset: i64 = @intCast((try readOperand(stream, opcode, context)).?.generic);
+ _ = offset;
+
+ switch (context.compile_unit.?.frame_base.?.*) {
+ .ExprLoc => {
+ // TODO: Run this expression in a nested stack machine
+ return error.UnimplementedOpcode;
+ },
+ .LocListOffset => {
+ // TODO: Read value from .debug_loclists
+ return error.UnimplementedOpcode;
+ },
+ .SecOffset => {
+ // TODO: Read value from .debug_loclists
+ return error.UnimplementedOpcode;
+ },
+ else => return error.InvalidFrameBase,
+ }
+ },
+ OP.breg0...OP.breg31,
+ OP.bregx,
+ => {
+ if (context.thread_context == null) return error.IncompleteExpressionContext;
+
+ const base_register = (try readOperand(stream, opcode, context)).?.base_register;
+ var value: i64 = @intCast(mem.readIntSliceNative(usize, try abi.regBytes(
+ context.thread_context.?,
+ base_register.base_register,
+ context.reg_context,
+ )));
+ value += base_register.offset;
+ try self.stack.append(allocator, .{ .generic = @intCast(value) });
+ },
+ OP.regval_type => {
+ const register_type = (try readOperand(stream, opcode, context)).?.register_type;
+ const value = mem.readIntSliceNative(usize, try abi.regBytes(
+ context.thread_context.?,
+ register_type.register,
+ context.reg_context,
+ ));
+ try self.stack.append(allocator, .{
+ .regval_type = .{
+ .type_offset = register_type.type_offset,
+ .type_size = @sizeOf(addr_type),
+ .value = value,
+ },
+ });
+ },
+
+ // 2.5.1.3: Stack Operations
+ OP.dup => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ try self.stack.append(allocator, self.stack.items[self.stack.items.len - 1]);
+ },
+ OP.drop => {
+ _ = self.stack.pop();
+ },
+ OP.pick, OP.over => {
+ const stack_index = if (opcode == OP.over) 1 else (try readOperand(stream, opcode, context)).?.generic;
+ if (stack_index >= self.stack.items.len) return error.InvalidExpression;
+ try self.stack.append(allocator, self.stack.items[self.stack.items.len - 1 - stack_index]);
+ },
+ OP.swap => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ mem.swap(Value, &self.stack.items[self.stack.items.len - 1], &self.stack.items[self.stack.items.len - 2]);
+ },
+ OP.rot => {
+ if (self.stack.items.len < 3) return error.InvalidExpression;
+ const first = self.stack.items[self.stack.items.len - 1];
+ self.stack.items[self.stack.items.len - 1] = self.stack.items[self.stack.items.len - 2];
+ self.stack.items[self.stack.items.len - 2] = self.stack.items[self.stack.items.len - 3];
+ self.stack.items[self.stack.items.len - 3] = first;
+ },
+ OP.deref,
+ OP.xderef,
+ OP.deref_size,
+ OP.xderef_size,
+ OP.deref_type,
+ OP.xderef_type,
+ => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ var addr = try self.stack.items[self.stack.items.len - 1].asIntegral();
+ const addr_space_identifier: ?usize = switch (opcode) {
+ OP.xderef,
+ OP.xderef_size,
+ OP.xderef_type,
+ => blk: {
+ _ = self.stack.pop();
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ break :blk try self.stack.items[self.stack.items.len - 1].asIntegral();
+ },
+ else => null,
+ };
+
+ // Usage of addr_space_identifier in the address calculation is implementation defined.
+ // This code will need to be updated to handle any architectures that utilize this.
+ _ = addr_space_identifier;
+
+ if (context.isValidMemory) |isValidMemory| if (!isValidMemory(addr)) return error.InvalidExpression;
+
+ const operand = try readOperand(stream, opcode, context);
+ const size = switch (opcode) {
+ OP.deref,
+ OP.xderef,
+ => @sizeOf(addr_type),
+ OP.deref_size,
+ OP.xderef_size,
+ => operand.?.type_size,
+ OP.deref_type,
+ OP.xderef_type,
+ => operand.?.deref_type.size,
+ else => unreachable,
+ };
+
+ const value: addr_type = std.math.cast(addr_type, @as(u64, switch (size) {
+ 1 => @as(*const u8, @ptrFromInt(addr)).*,
+ 2 => @as(*const u16, @ptrFromInt(addr)).*,
+ 4 => @as(*const u32, @ptrFromInt(addr)).*,
+ 8 => @as(*const u64, @ptrFromInt(addr)).*,
+ else => return error.InvalidExpression,
+ })) orelse return error.InvalidExpression;
+
+ switch (opcode) {
+ OP.deref_type,
+ OP.xderef_type,
+ => {
+ self.stack.items[self.stack.items.len - 1] = .{
+ .regval_type = .{
+ .type_offset = operand.?.deref_type.type_offset,
+ .type_size = operand.?.deref_type.size,
+ .value = value,
+ },
+ };
+ },
+ else => {
+ self.stack.items[self.stack.items.len - 1] = .{ .generic = value };
+ },
+ }
+ },
+ OP.push_object_address => {
+ // In sub-expressions, `push_object_address` is not meaningful (as per the
+ // spec), so treat it like a nop
+ if (!context.entry_value_context) {
+ if (context.object_address == null) return error.IncompleteExpressionContext;
+ try self.stack.append(allocator, .{ .generic = @intFromPtr(context.object_address.?) });
+ }
+ },
+ OP.form_tls_address => {
+ return error.UnimplementedOpcode;
+ },
+ OP.call_frame_cfa => {
+ if (context.cfa) |cfa| {
+ try self.stack.append(allocator, .{ .generic = cfa });
+ } else return error.IncompleteExpressionContext;
+ },
+
+ // 2.5.1.4: Arithmetic and Logical Operations
+ OP.abs => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ const value: isize = @bitCast(try self.stack.items[self.stack.items.len - 1].asIntegral());
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = std.math.absCast(value),
+ };
+ },
+ OP.@"and" => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = try self.stack.pop().asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = a & try self.stack.items[self.stack.items.len - 1].asIntegral(),
+ };
+ },
+ OP.div => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a: isize = @bitCast(try self.stack.pop().asIntegral());
+ const b: isize = @bitCast(try self.stack.items[self.stack.items.len - 1].asIntegral());
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = @bitCast(try std.math.divTrunc(isize, b, a)),
+ };
+ },
+ OP.minus => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const b = try self.stack.pop().asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = try std.math.sub(addr_type, try self.stack.items[self.stack.items.len - 1].asIntegral(), b),
+ };
+ },
+ OP.mod => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a: isize = @bitCast(try self.stack.pop().asIntegral());
+ const b: isize = @bitCast(try self.stack.items[self.stack.items.len - 1].asIntegral());
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = @bitCast(@mod(b, a)),
+ };
+ },
+ OP.mul => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a: isize = @bitCast(try self.stack.pop().asIntegral());
+ const b: isize = @bitCast(try self.stack.items[self.stack.items.len - 1].asIntegral());
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = @bitCast(@mulWithOverflow(a, b)[0]),
+ };
+ },
+ OP.neg => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = @bitCast(
+ try std.math.negate(
+ @as(isize, @bitCast(try self.stack.items[self.stack.items.len - 1].asIntegral())),
+ ),
+ ),
+ };
+ },
+ OP.not => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = ~try self.stack.items[self.stack.items.len - 1].asIntegral(),
+ };
+ },
+ OP.@"or" => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = try self.stack.pop().asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = a | try self.stack.items[self.stack.items.len - 1].asIntegral(),
+ };
+ },
+ OP.plus => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const b = try self.stack.pop().asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = try std.math.add(addr_type, try self.stack.items[self.stack.items.len - 1].asIntegral(), b),
+ };
+ },
+ OP.plus_uconst => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ const constant = (try readOperand(stream, opcode, context)).?.generic;
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = try std.math.add(addr_type, try self.stack.items[self.stack.items.len - 1].asIntegral(), constant),
+ };
+ },
+ OP.shl => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = try self.stack.pop().asIntegral();
+ const b = try self.stack.items[self.stack.items.len - 1].asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = std.math.shl(usize, b, a),
+ };
+ },
+ OP.shr => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = try self.stack.pop().asIntegral();
+ const b = try self.stack.items[self.stack.items.len - 1].asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = std.math.shr(usize, b, a),
+ };
+ },
+ OP.shra => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = try self.stack.pop().asIntegral();
+ const b: isize = @bitCast(try self.stack.items[self.stack.items.len - 1].asIntegral());
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = @bitCast(std.math.shr(isize, b, a)),
+ };
+ },
+ OP.xor => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = try self.stack.pop().asIntegral();
+ self.stack.items[self.stack.items.len - 1] = .{
+ .generic = a ^ try self.stack.items[self.stack.items.len - 1].asIntegral(),
+ };
+ },
+
+ // 2.5.1.5: Control Flow Operations
+ OP.le,
+ OP.ge,
+ OP.eq,
+ OP.lt,
+ OP.gt,
+ OP.ne,
+ => {
+ if (self.stack.items.len < 2) return error.InvalidExpression;
+ const a = self.stack.pop();
+ const b = self.stack.items[self.stack.items.len - 1];
+
+ if (a == .generic and b == .generic) {
+ const a_int: isize = @bitCast(a.asIntegral() catch unreachable);
+ const b_int: isize = @bitCast(b.asIntegral() catch unreachable);
+ const result = @intFromBool(switch (opcode) {
+ OP.le => b_int <= a_int,
+ OP.ge => b_int >= a_int,
+ OP.eq => b_int == a_int,
+ OP.lt => b_int < a_int,
+ OP.gt => b_int > a_int,
+ OP.ne => b_int != a_int,
+ else => unreachable,
+ });
+
+ self.stack.items[self.stack.items.len - 1] = .{ .generic = result };
+ } else {
+ // TODO: Load the types referenced by these values, find their comparison operator, and run it
+ return error.UnimplementedTypedComparison;
+ }
+ },
+ OP.skip, OP.bra => {
+ const branch_offset = (try readOperand(stream, opcode, context)).?.branch_offset;
+ const condition = if (opcode == OP.bra) blk: {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ break :blk try self.stack.pop().asIntegral() != 0;
+ } else true;
+
+ if (condition) {
+ const new_pos = std.math.cast(
+ usize,
+ try std.math.add(isize, @as(isize, @intCast(stream.pos)), branch_offset),
+ ) orelse return error.InvalidExpression;
+
+ if (new_pos < 0 or new_pos > stream.buffer.len) return error.InvalidExpression;
+ stream.pos = new_pos;
+ }
+ },
+ OP.call2,
+ OP.call4,
+ OP.call_ref,
+ => {
+ const debug_info_offset = (try readOperand(stream, opcode, context)).?.generic;
+ _ = debug_info_offset;
+
+ // TODO: Load a DIE entry at debug_info_offset in a .debug_info section (the spec says that it
+ // can be in a separate exe / shared object from the one containing this expression).
+ // Transfer control to the DW_AT_location attribute, with the current stack as input.
+
+ return error.UnimplementedExpressionCall;
+ },
+
+ // 2.5.1.6: Type Conversions
+ OP.convert => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ const type_offset = (try readOperand(stream, opcode, context)).?.generic;
+
+ // TODO: Load the DW_TAG_base_type entries in context.compile_unit and verify both types are the same size
+ const value = self.stack.items[self.stack.items.len - 1];
+ if (type_offset == 0) {
+ self.stack.items[self.stack.items.len - 1] = .{ .generic = try value.asIntegral() };
+ } else {
+ // TODO: Load the DW_TAG_base_type entry in context.compile_unit, find a conversion operator
+ // from the old type to the new type, run it.
+ return error.UnimplementedTypeConversion;
+ }
+ },
+ OP.reinterpret => {
+ if (self.stack.items.len == 0) return error.InvalidExpression;
+ const type_offset = (try readOperand(stream, opcode, context)).?.generic;
+
+ // TODO: Load the DW_TAG_base_type entries in context.compile_unit and verify both types are the same size
+ const value = self.stack.items[self.stack.items.len - 1];
+ if (type_offset == 0) {
+ self.stack.items[self.stack.items.len - 1] = .{ .generic = try value.asIntegral() };
+ } else {
+ self.stack.items[self.stack.items.len - 1] = switch (value) {
+ .generic => |v| .{
+ .regval_type = .{
+ .type_offset = type_offset,
+ .type_size = @sizeOf(addr_type),
+ .value = v,
+ },
+ },
+ .regval_type => |r| .{
+ .regval_type = .{
+ .type_offset = type_offset,
+ .type_size = r.type_size,
+ .value = r.value,
+ },
+ },
+ .const_type => |c| .{
+ .const_type = .{
+ .type_offset = type_offset,
+ .value_bytes = c.value_bytes,
+ },
+ },
+ };
+ }
+ },
+
+ // 2.5.1.7: Special Operations
+ OP.nop => {},
+ OP.entry_value => {
+ const block = (try readOperand(stream, opcode, context)).?.block;
+ if (block.len == 0) return error.InvalidSubExpression;
+
+ // TODO: The spec states that this sub-expression needs to observe the state (ie. registers)
+ // as it was upon entering the current subprogram. If this isn't being called at the
+ // end of a frame unwind operation, an additional ThreadContext with this state will be needed.
+
+ if (isOpcodeRegisterLocation(block[0])) {
+ if (context.thread_context == null) return error.IncompleteExpressionContext;
+
+ var block_stream = std.io.fixedBufferStream(block);
+ const register = (try readOperand(&block_stream, block[0], context)).?.register;
+ const value = mem.readIntSliceNative(usize, try abi.regBytes(context.thread_context.?, register, context.reg_context));
+ try self.stack.append(allocator, .{ .generic = value });
+ } else {
+ var stack_machine: Self = .{};
+ defer stack_machine.deinit(allocator);
+
+ var sub_context = context;
+ sub_context.entry_value_context = true;
+ const result = try stack_machine.run(block, allocator, sub_context, null);
+ try self.stack.append(allocator, result orelse return error.InvalidSubExpression);
+ }
+ },
+
+ // These have already been handled by readOperand
+ OP.lo_user...OP.hi_user => unreachable,
+ else => {
+ //std.debug.print("Unknown DWARF expression opcode: {x}\n", .{opcode});
+ return error.UnknownExpressionOpcode;
+ },
+ }
+
+ return stream.pos < stream.buffer.len;
+ }
+ };
+}
+
+pub fn Builder(comptime options: ExpressionOptions) type {
+ const addr_type = switch (options.addr_size) {
+ 2 => u16,
+ 4 => u32,
+ 8 => u64,
+ else => @compileError("Unsupported address size of " ++ options.addr_size),
+ };
+
+ return struct {
+ /// Zero-operand instructions
+ pub fn writeOpcode(writer: anytype, comptime opcode: u8) !void {
+ if (options.call_frame_context and !comptime isOpcodeValidInCFA(opcode)) return error.InvalidCFAOpcode;
+ switch (opcode) {
+ OP.dup,
+ OP.drop,
+ OP.over,
+ OP.swap,
+ OP.rot,
+ OP.deref,
+ OP.xderef,
+ OP.push_object_address,
+ OP.form_tls_address,
+ OP.call_frame_cfa,
+ OP.abs,
+ OP.@"and",
+ OP.div,
+ OP.minus,
+ OP.mod,
+ OP.mul,
+ OP.neg,
+ OP.not,
+ OP.@"or",
+ OP.plus,
+ OP.shl,
+ OP.shr,
+ OP.shra,
+ OP.xor,
+ OP.le,
+ OP.ge,
+ OP.eq,
+ OP.lt,
+ OP.gt,
+ OP.ne,
+ OP.nop,
+ OP.stack_value,
+ => try writer.writeByte(opcode),
+ else => @compileError("This opcode requires operands, use `write<Opcode>()` instead"),
+ }
+ }
+
+ // 2.5.1.1: Literal Encodings
+ pub fn writeLiteral(writer: anytype, literal: u8) !void {
+ switch (literal) {
+ 0...31 => |n| try writer.writeByte(n + OP.lit0),
+ else => return error.InvalidLiteral,
+ }
+ }
+
+ pub fn writeConst(writer: anytype, comptime T: type, value: T) !void {
+ if (@typeInfo(T) != .Int) @compileError("Constants must be integers");
+
+ switch (T) {
+ u8, i8, u16, i16, u32, i32, u64, i64 => {
+ try writer.writeByte(switch (T) {
+ u8 => OP.const1u,
+ i8 => OP.const1s,
+ u16 => OP.const2u,
+ i16 => OP.const2s,
+ u32 => OP.const4u,
+ i32 => OP.const4s,
+ u64 => OP.const8u,
+ i64 => OP.const8s,
+ else => unreachable,
+ });
+
+ try writer.writeInt(T, value, options.endian);
+ },
+ else => switch (@typeInfo(T).Int.signedness) {
+ .unsigned => {
+ try writer.writeByte(OP.constu);
+ try leb.writeULEB128(writer, value);
+ },
+ .signed => {
+ try writer.writeByte(OP.consts);
+ try leb.writeILEB128(writer, value);
+ },
+ },
+ }
+ }
+
+ pub fn writeConstx(writer: anytype, debug_addr_offset: anytype) !void {
+ try writer.writeByte(OP.constx);
+ try leb.writeULEB128(writer, debug_addr_offset);
+ }
+
+ pub fn writeConstType(writer: anytype, die_offset: anytype, value_bytes: []const u8) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ if (value_bytes.len > 0xff) return error.InvalidTypeLength;
+ try writer.writeByte(OP.const_type);
+ try leb.writeULEB128(writer, die_offset);
+ try writer.writeByte(@intCast(value_bytes.len));
+ try writer.writeAll(value_bytes);
+ }
+
+ pub fn writeAddr(writer: anytype, value: addr_type) !void {
+ try writer.writeByte(OP.addr);
+ try writer.writeInt(addr_type, value, options.endian);
+ }
+
+ pub fn writeAddrx(writer: anytype, debug_addr_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ try writer.writeByte(OP.addrx);
+ try leb.writeULEB128(writer, debug_addr_offset);
+ }
+
+ // 2.5.1.2: Register Values
+ pub fn writeFbreg(writer: anytype, offset: anytype) !void {
+ try writer.writeByte(OP.fbreg);
+ try leb.writeILEB128(writer, offset);
+ }
+
+ pub fn writeBreg(writer: anytype, register: u8, offset: anytype) !void {
+ if (register > 31) return error.InvalidRegister;
+ try writer.writeByte(OP.breg0 + register);
+ try leb.writeILEB128(writer, offset);
+ }
+
+ pub fn writeBregx(writer: anytype, register: anytype, offset: anytype) !void {
+ try writer.writeByte(OP.bregx);
+ try leb.writeULEB128(writer, register);
+ try leb.writeILEB128(writer, offset);
+ }
+
+ pub fn writeRegvalType(writer: anytype, register: anytype, offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ try writer.writeByte(OP.regval_type);
+ try leb.writeULEB128(writer, register);
+ try leb.writeULEB128(writer, offset);
+ }
+
+ // 2.5.1.3: Stack Operations
+ pub fn writePick(writer: anytype, index: u8) !void {
+ try writer.writeByte(OP.pick);
+ try writer.writeByte(index);
+ }
+
+ pub fn writeDerefSize(writer: anytype, size: u8) !void {
+ try writer.writeByte(OP.deref_size);
+ try writer.writeByte(size);
+ }
+
+ pub fn writeXDerefSize(writer: anytype, size: u8) !void {
+ try writer.writeByte(OP.xderef_size);
+ try writer.writeByte(size);
+ }
+
+ pub fn writeDerefType(writer: anytype, size: u8, die_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ try writer.writeByte(OP.deref_type);
+ try writer.writeByte(size);
+ try leb.writeULEB128(writer, die_offset);
+ }
+
+ pub fn writeXDerefType(writer: anytype, size: u8, die_offset: anytype) !void {
+ try writer.writeByte(OP.xderef_type);
+ try writer.writeByte(size);
+ try leb.writeULEB128(writer, die_offset);
+ }
+
+ // 2.5.1.4: Arithmetic and Logical Operations
+
+ pub fn writePlusUconst(writer: anytype, uint_value: anytype) !void {
+ try writer.writeByte(OP.plus_uconst);
+ try leb.writeULEB128(writer, uint_value);
+ }
+
+ // 2.5.1.5: Control Flow Operations
+
+ pub fn writeSkip(writer: anytype, offset: i16) !void {
+ try writer.writeByte(OP.skip);
+ try writer.writeInt(i16, offset, options.endian);
+ }
+
+ pub fn writeBra(writer: anytype, offset: i16) !void {
+ try writer.writeByte(OP.bra);
+ try writer.writeInt(i16, offset, options.endian);
+ }
+
+ pub fn writeCall(writer: anytype, comptime T: type, offset: T) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ switch (T) {
+ u16 => try writer.writeByte(OP.call2),
+ u32 => try writer.writeByte(OP.call4),
+ else => @compileError("Call operand must be a 2 or 4 byte offset"),
+ }
+
+ try writer.writeInt(T, offset, options.endian);
+ }
+
+ pub fn writeCallRef(writer: anytype, comptime is_64: bool, value: if (is_64) u64 else u32) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ try writer.writeByte(OP.call_ref);
+ try writer.writeInt(if (is_64) u64 else u32, value, options.endian);
+ }
+
+ pub fn writeConvert(writer: anytype, die_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ try writer.writeByte(OP.convert);
+ try leb.writeULEB128(writer, die_offset);
+ }
+
+ pub fn writeReinterpret(writer: anytype, die_offset: anytype) !void {
+ if (options.call_frame_context) return error.InvalidCFAOpcode;
+ try writer.writeByte(OP.reinterpret);
+ try leb.writeULEB128(writer, die_offset);
+ }
+
+ // 2.5.1.7: Special Operations
+
+ pub fn writeEntryValue(writer: anytype, expression: []const u8) !void {
+ try writer.writeByte(OP.entry_value);
+ try leb.writeULEB128(writer, expression.len);
+ try writer.writeAll(expression);
+ }
+
+ // 2.6: Location Descriptions
+ pub fn writeReg(writer: anytype, register: u8) !void {
+ try writer.writeByte(OP.reg0 + register);
+ }
+
+ pub fn writeRegx(writer: anytype, register: anytype) !void {
+ try writer.writeByte(OP.regx);
+ try leb.writeULEB128(writer, register);
+ }
+
+ pub fn writeImplicitValue(writer: anytype, value_bytes: []const u8) !void {
+ try writer.writeByte(OP.implicit_value);
+ try leb.writeULEB128(writer, value_bytes.len);
+ try writer.writeAll(value_bytes);
+ }
+ };
+}
+
+// Certain opcodes are not allowed in a CFA context, see 6.4.2
+fn isOpcodeValidInCFA(opcode: u8) bool {
+ return switch (opcode) {
+ OP.addrx,
+ OP.call2,
+ OP.call4,
+ OP.call_ref,
+ OP.const_type,
+ OP.constx,
+ OP.convert,
+ OP.deref_type,
+ OP.regval_type,
+ OP.reinterpret,
+ OP.push_object_address,
+ OP.call_frame_cfa,
+ => false,
+ else => true,
+ };
+}
+
+fn isOpcodeRegisterLocation(opcode: u8) bool {
+ return switch (opcode) {
+ OP.reg0...OP.reg31, OP.regx => true,
+ else => false,
+ };
+}
+
+const testing = std.testing;
+test "DWARF expressions" {
+ const allocator = std.testing.allocator;
+
+ const options = ExpressionOptions{};
+ var stack_machine = StackMachine(options){};
+ defer stack_machine.deinit(allocator);
+
+ const b = Builder(options);
+
+ var program = std.ArrayList(u8).init(allocator);
+ defer program.deinit();
+
+ const writer = program.writer();
+
+ // Literals
+ {
+ const context = ExpressionContext{};
+ for (0..32) |i| {
+ try b.writeLiteral(writer, @intCast(i));
+ }
+
+ _ = try stack_machine.run(program.items, allocator, context, 0);
+
+ for (0..32) |i| {
+ const expected = 31 - i;
+ try testing.expectEqual(expected, stack_machine.stack.popOrNull().?.generic);
+ }
+ }
+
+ // Constants
+ {
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+
+ const input = [_]comptime_int{
+ 1,
+ -1,
+ @as(usize, @truncate(0x0fff)),
+ @as(isize, @truncate(-0x0fff)),
+ @as(usize, @truncate(0x0fffffff)),
+ @as(isize, @truncate(-0x0fffffff)),
+ @as(usize, @truncate(0x0fffffffffffffff)),
+ @as(isize, @truncate(-0x0fffffffffffffff)),
+ @as(usize, @truncate(0x8000000)),
+ @as(isize, @truncate(-0x8000000)),
+ @as(usize, @truncate(0x12345678_12345678)),
+ @as(usize, @truncate(0xffffffff_ffffffff)),
+ @as(usize, @truncate(0xeeeeeeee_eeeeeeee)),
+ };
+
+ try b.writeConst(writer, u8, input[0]);
+ try b.writeConst(writer, i8, input[1]);
+ try b.writeConst(writer, u16, input[2]);
+ try b.writeConst(writer, i16, input[3]);
+ try b.writeConst(writer, u32, input[4]);
+ try b.writeConst(writer, i32, input[5]);
+ try b.writeConst(writer, u64, input[6]);
+ try b.writeConst(writer, i64, input[7]);
+ try b.writeConst(writer, u28, input[8]);
+ try b.writeConst(writer, i28, input[9]);
+ try b.writeAddr(writer, input[10]);
+
+ var mock_compile_unit: dwarf.CompileUnit = undefined;
+ mock_compile_unit.addr_base = 1;
+
+ var mock_debug_addr = std.ArrayList(u8).init(allocator);
+ defer mock_debug_addr.deinit();
+
+ try mock_debug_addr.writer().writeIntNative(u16, 0);
+ try mock_debug_addr.writer().writeIntNative(usize, input[11]);
+ try mock_debug_addr.writer().writeIntNative(usize, input[12]);
+
+ const context = ExpressionContext{
+ .compile_unit = &mock_compile_unit,
+ .debug_addr = mock_debug_addr.items,
+ };
+
+ try b.writeConstx(writer, @as(usize, 1));
+ try b.writeAddrx(writer, @as(usize, 1 + @sizeOf(usize)));
+
+ const die_offset: usize = @truncate(0xaabbccdd);
+ const type_bytes: []const u8 = &.{ 1, 2, 3, 4 };
+ try b.writeConstType(writer, die_offset, type_bytes);
+
+ _ = try stack_machine.run(program.items, allocator, context, 0);
+
+ const const_type = stack_machine.stack.popOrNull().?.const_type;
+ try testing.expectEqual(die_offset, const_type.type_offset);
+ try testing.expectEqualSlices(u8, type_bytes, const_type.value_bytes);
+
+ const expected = .{
+ .{ usize, input[12], usize },
+ .{ usize, input[11], usize },
+ .{ usize, input[10], usize },
+ .{ isize, input[9], isize },
+ .{ usize, input[8], usize },
+ .{ isize, input[7], isize },
+ .{ usize, input[6], usize },
+ .{ isize, input[5], isize },
+ .{ usize, input[4], usize },
+ .{ isize, input[3], isize },
+ .{ usize, input[2], usize },
+ .{ isize, input[1], isize },
+ .{ usize, input[0], usize },
+ };
+
+ inline for (expected) |e| {
+ try testing.expectEqual(@as(e[0], e[1]), @as(e[2], @bitCast(stack_machine.stack.popOrNull().?.generic)));
+ }
+ }
+
+ // Register values
+ if (@sizeOf(std.debug.ThreadContext) != 0) {
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+
+ const reg_context = abi.RegisterContext{
+ .eh_frame = true,
+ .is_macho = builtin.os.tag == .macos,
+ };
+ var thread_context: std.debug.ThreadContext = undefined;
+ std.debug.relocateContext(&thread_context);
+ const context = ExpressionContext{
+ .thread_context = &thread_context,
+ .reg_context = reg_context,
+ };
+
+ // Only test register operations on arch / os that have them implemented
+ if (abi.regBytes(&thread_context, 0, reg_context)) |reg_bytes| {
+
+ // TODO: Test fbreg (once implemented): mock a DIE and point compile_unit.frame_base at it
+
+ mem.writeIntSliceNative(usize, reg_bytes, 0xee);
+ (try abi.regValueNative(usize, &thread_context, abi.fpRegNum(reg_context), reg_context)).* = 1;
+ (try abi.regValueNative(usize, &thread_context, abi.spRegNum(reg_context), reg_context)).* = 2;
+ (try abi.regValueNative(usize, &thread_context, abi.ipRegNum(), reg_context)).* = 3;
+
+ try b.writeBreg(writer, abi.fpRegNum(reg_context), @as(usize, 100));
+ try b.writeBreg(writer, abi.spRegNum(reg_context), @as(usize, 200));
+ try b.writeBregx(writer, abi.ipRegNum(), @as(usize, 300));
+ try b.writeRegvalType(writer, @as(u8, 0), @as(usize, 400));
+
+ _ = try stack_machine.run(program.items, allocator, context, 0);
+
+ const regval_type = stack_machine.stack.popOrNull().?.regval_type;
+ try testing.expectEqual(@as(usize, 400), regval_type.type_offset);
+ try testing.expectEqual(@as(u8, @sizeOf(usize)), regval_type.type_size);
+ try testing.expectEqual(@as(usize, 0xee), regval_type.value);
+
+ try testing.expectEqual(@as(usize, 303), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 202), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 101), stack_machine.stack.popOrNull().?.generic);
+ } else |err| {
+ switch (err) {
+ error.UnimplementedArch,
+ error.UnimplementedOs,
+ error.ThreadContextNotSupported,
+ => {},
+ else => return err,
+ }
+ }
+ }
+
+ // Stack operations
+ {
+ var context = ExpressionContext{};
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u8, 1);
+ try b.writeOpcode(writer, OP.dup);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 1), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 1), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u8, 1);
+ try b.writeOpcode(writer, OP.drop);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expect(stack_machine.stack.popOrNull() == null);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u8, 4);
+ try b.writeConst(writer, u8, 5);
+ try b.writeConst(writer, u8, 6);
+ try b.writePick(writer, 2);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 4), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u8, 4);
+ try b.writeConst(writer, u8, 5);
+ try b.writeConst(writer, u8, 6);
+ try b.writeOpcode(writer, OP.over);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 5), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u8, 5);
+ try b.writeConst(writer, u8, 6);
+ try b.writeOpcode(writer, OP.swap);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 5), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 6), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u8, 4);
+ try b.writeConst(writer, u8, 5);
+ try b.writeConst(writer, u8, 6);
+ try b.writeOpcode(writer, OP.rot);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 5), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 4), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 6), stack_machine.stack.popOrNull().?.generic);
+
+ const deref_target: usize = @truncate(0xffeeffee_ffeeffee);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeAddr(writer, @intFromPtr(&deref_target));
+ try b.writeOpcode(writer, OP.deref);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(deref_target, stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeLiteral(writer, 0);
+ try b.writeAddr(writer, @intFromPtr(&deref_target));
+ try b.writeOpcode(writer, OP.xderef);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(deref_target, stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeAddr(writer, @intFromPtr(&deref_target));
+ try b.writeDerefSize(writer, 1);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeLiteral(writer, 0);
+ try b.writeAddr(writer, @intFromPtr(&deref_target));
+ try b.writeXDerefSize(writer, 1);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), stack_machine.stack.popOrNull().?.generic);
+
+ const type_offset: usize = @truncate(0xaabbaabb_aabbaabb);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeAddr(writer, @intFromPtr(&deref_target));
+ try b.writeDerefType(writer, 1, type_offset);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ const deref_type = stack_machine.stack.popOrNull().?.regval_type;
+ try testing.expectEqual(type_offset, deref_type.type_offset);
+ try testing.expectEqual(@as(u8, 1), deref_type.type_size);
+ try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), deref_type.value);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeLiteral(writer, 0);
+ try b.writeAddr(writer, @intFromPtr(&deref_target));
+ try b.writeXDerefType(writer, 1, type_offset);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ const xderef_type = stack_machine.stack.popOrNull().?.regval_type;
+ try testing.expectEqual(type_offset, xderef_type.type_offset);
+ try testing.expectEqual(@as(u8, 1), xderef_type.type_size);
+ try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), xderef_type.value);
+
+ context.object_address = &deref_target;
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeOpcode(writer, OP.push_object_address);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, @intFromPtr(context.object_address.?)), stack_machine.stack.popOrNull().?.generic);
+
+ // TODO: Test OP.form_tls_address
+
+ context.cfa = @truncate(0xccddccdd_ccddccdd);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeOpcode(writer, OP.call_frame_cfa);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(context.cfa.?, stack_machine.stack.popOrNull().?.generic);
+ }
+
+ // Arithmetic and Logical Operations
+ {
+ var context = ExpressionContext{};
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, i16, -4096);
+ try b.writeOpcode(writer, OP.abs);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 4096), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xff0f);
+ try b.writeConst(writer, u16, 0xf0ff);
+ try b.writeOpcode(writer, OP.@"and");
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0xf00f), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, i16, -404);
+ try b.writeConst(writer, i16, 100);
+ try b.writeOpcode(writer, OP.div);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(isize, -404 / 100), @as(isize, @bitCast(stack_machine.stack.popOrNull().?.generic)));
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 200);
+ try b.writeConst(writer, u16, 50);
+ try b.writeOpcode(writer, OP.minus);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 150), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 123);
+ try b.writeConst(writer, u16, 100);
+ try b.writeOpcode(writer, OP.mod);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 23), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xff);
+ try b.writeConst(writer, u16, 0xee);
+ try b.writeOpcode(writer, OP.mul);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0xed12), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 5);
+ try b.writeOpcode(writer, OP.neg);
+ try b.writeConst(writer, i16, -6);
+ try b.writeOpcode(writer, OP.neg);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 6), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(isize, -5), @as(isize, @bitCast(stack_machine.stack.popOrNull().?.generic)));
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xff0f);
+ try b.writeOpcode(writer, OP.not);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(~@as(usize, 0xff0f), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xff0f);
+ try b.writeConst(writer, u16, 0xf0ff);
+ try b.writeOpcode(writer, OP.@"or");
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0xffff), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, i16, 402);
+ try b.writeConst(writer, i16, 100);
+ try b.writeOpcode(writer, OP.plus);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 502), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 4096);
+ try b.writePlusUconst(writer, @as(usize, 8192));
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 4096 + 8192), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xfff);
+ try b.writeConst(writer, u16, 1);
+ try b.writeOpcode(writer, OP.shl);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0xfff << 1), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xfff);
+ try b.writeConst(writer, u16, 1);
+ try b.writeOpcode(writer, OP.shr);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0xfff >> 1), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xfff);
+ try b.writeConst(writer, u16, 1);
+ try b.writeOpcode(writer, OP.shr);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, @bitCast(@as(isize, 0xfff) >> 1)), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConst(writer, u16, 0xf0ff);
+ try b.writeConst(writer, u16, 0xff0f);
+ try b.writeOpcode(writer, OP.xor);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0x0ff0), stack_machine.stack.popOrNull().?.generic);
+ }
+
+ // Control Flow Operations
+ {
+ var context = ExpressionContext{};
+ const expected = .{
+ .{ OP.le, 1, 1, 0 },
+ .{ OP.ge, 1, 0, 1 },
+ .{ OP.eq, 1, 0, 0 },
+ .{ OP.lt, 0, 1, 0 },
+ .{ OP.gt, 0, 0, 1 },
+ .{ OP.ne, 0, 1, 1 },
+ };
+
+ inline for (expected) |e| {
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+
+ try b.writeConst(writer, u16, 0);
+ try b.writeConst(writer, u16, 0);
+ try b.writeOpcode(writer, e[0]);
+ try b.writeConst(writer, u16, 0);
+ try b.writeConst(writer, u16, 1);
+ try b.writeOpcode(writer, e[0]);
+ try b.writeConst(writer, u16, 1);
+ try b.writeConst(writer, u16, 0);
+ try b.writeOpcode(writer, e[0]);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, e[3]), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, e[2]), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, e[1]), stack_machine.stack.popOrNull().?.generic);
+ }
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeLiteral(writer, 2);
+ try b.writeSkip(writer, 1);
+ try b.writeLiteral(writer, 3);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 2), stack_machine.stack.popOrNull().?.generic);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeLiteral(writer, 2);
+ try b.writeBra(writer, 1);
+ try b.writeLiteral(writer, 3);
+ try b.writeLiteral(writer, 0);
+ try b.writeBra(writer, 1);
+ try b.writeLiteral(writer, 4);
+ try b.writeLiteral(writer, 5);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 5), stack_machine.stack.popOrNull().?.generic);
+ try testing.expectEqual(@as(usize, 4), stack_machine.stack.popOrNull().?.generic);
+ try testing.expect(stack_machine.stack.popOrNull() == null);
+
+ // TODO: Test call2, call4, call_ref once implemented
+
+ }
+
+ // Type conversions
+ {
+ var context = ExpressionContext{};
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+
+ // TODO: Test typed OP.convert once implemented
+
+ const value: usize = @truncate(0xffeeffee_ffeeffee);
+ var value_bytes: [options.addr_size]u8 = undefined;
+ mem.writeIntSliceNative(usize, &value_bytes, value);
+
+ // Convert to generic type
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConstType(writer, @as(usize, 0), &value_bytes);
+ try b.writeConvert(writer, @as(usize, 0));
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(value, stack_machine.stack.popOrNull().?.generic);
+
+ // Reinterpret to generic type
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConstType(writer, @as(usize, 0), &value_bytes);
+ try b.writeReinterpret(writer, @as(usize, 0));
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(value, stack_machine.stack.popOrNull().?.generic);
+
+ // Reinterpret to new type
+ const die_offset: usize = 0xffee;
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeConstType(writer, @as(usize, 0), &value_bytes);
+ try b.writeReinterpret(writer, die_offset);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ const const_type = stack_machine.stack.popOrNull().?.const_type;
+ try testing.expectEqual(die_offset, const_type.type_offset);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeLiteral(writer, 0);
+ try b.writeReinterpret(writer, die_offset);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ const regval_type = stack_machine.stack.popOrNull().?.regval_type;
+ try testing.expectEqual(die_offset, regval_type.type_offset);
+ }
+
+ // Special operations
+ {
+ var context = ExpressionContext{};
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeOpcode(writer, OP.nop);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expect(stack_machine.stack.popOrNull() == null);
+
+ // Sub-expression
+ {
+ var sub_program = std.ArrayList(u8).init(allocator);
+ defer sub_program.deinit();
+ const sub_writer = sub_program.writer();
+ try b.writeLiteral(sub_writer, 3);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeEntryValue(writer, sub_program.items);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 3), stack_machine.stack.popOrNull().?.generic);
+ }
+
+ // Register location description
+ const reg_context = abi.RegisterContext{
+ .eh_frame = true,
+ .is_macho = builtin.os.tag == .macos,
+ };
+ var thread_context: std.debug.ThreadContext = undefined;
+ std.debug.relocateContext(&thread_context);
+ context = ExpressionContext{
+ .thread_context = &thread_context,
+ .reg_context = reg_context,
+ };
+
+ if (abi.regBytes(&thread_context, 0, reg_context)) |reg_bytes| {
+ mem.writeIntSliceNative(usize, reg_bytes, 0xee);
+
+ var sub_program = std.ArrayList(u8).init(allocator);
+ defer sub_program.deinit();
+ const sub_writer = sub_program.writer();
+ try b.writeReg(sub_writer, 0);
+
+ stack_machine.reset();
+ program.clearRetainingCapacity();
+ try b.writeEntryValue(writer, sub_program.items);
+ _ = try stack_machine.run(program.items, allocator, context, null);
+ try testing.expectEqual(@as(usize, 0xee), stack_machine.stack.popOrNull().?.generic);
+ } else |err| {
+ switch (err) {
+ error.UnimplementedArch,
+ error.UnimplementedOs,
+ error.ThreadContextNotSupported,
+ => {},
+ else => return err,
+ }
+ }
+ }
+}
diff --git a/lib/std/elf.zig b/lib/std/elf.zig
@@ -371,6 +371,9 @@ pub const SHT_LOUSER = 0x80000000;
/// End of application-specific
pub const SHT_HIUSER = 0xffffffff;
+// Note type for .note.gnu.build_id
+pub const NT_GNU_BUILD_ID = 3;
+
/// Local symbol
pub const STB_LOCAL = 0;
/// Global symbol
@@ -1055,6 +1058,11 @@ pub const Shdr = switch (@sizeOf(usize)) {
8 => Elf64_Shdr,
else => @compileError("expected pointer size of 32 or 64"),
};
+pub const Chdr = switch (@sizeOf(usize)) {
+ 4 => Elf32_Chdr,
+ 8 => Elf64_Chdr,
+ else => @compileError("expected pointer size of 32 or 64"),
+};
pub const Sym = switch (@sizeOf(usize)) {
4 => Elf32_Sym,
8 => Elf64_Sym,
diff --git a/lib/std/macho.zig b/lib/std/macho.zig
@@ -2064,3 +2064,64 @@ pub const UNWIND_ARM64_FRAME_D14_D15_PAIR: u32 = 0x00000800;
pub const UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK: u32 = 0x00FFF000;
pub const UNWIND_ARM64_DWARF_SECTION_OFFSET: u32 = 0x00FFFFFF;
+
+pub const CompactUnwindEncoding = packed struct(u32) {
+ value: packed union {
+ x86_64: packed union {
+ frame: packed struct(u24) {
+ reg4: u3,
+ reg3: u3,
+ reg2: u3,
+ reg1: u3,
+ reg0: u3,
+ unused: u1 = 0,
+ frame_offset: u8,
+ },
+ frameless: packed struct(u24) {
+ stack_reg_permutation: u10,
+ stack_reg_count: u3,
+ stack: packed union {
+ direct: packed struct(u11) {
+ _: u3,
+ stack_size: u8,
+ },
+ indirect: packed struct(u11) {
+ stack_adjust: u3,
+ sub_offset: u8,
+ },
+ },
+ },
+ dwarf: u24,
+ },
+ arm64: packed union {
+ frame: packed struct(u24) {
+ x_reg_pairs: packed struct(u5) {
+ x19_x20: u1,
+ x21_x22: u1,
+ x23_x24: u1,
+ x25_x26: u1,
+ x27_x28: u1,
+ },
+ d_reg_pairs: packed struct(u4) {
+ d8_d9: u1,
+ d10_d11: u1,
+ d12_d13: u1,
+ d14_d15: u1,
+ },
+ _: u15,
+ },
+ frameless: packed struct(u24) {
+ _: u12 = 0,
+ stack_size: u12,
+ },
+ dwarf: u24,
+ },
+ },
+ mode: packed union {
+ x86_64: UNWIND_X86_64_MODE,
+ arm64: UNWIND_ARM64_MODE,
+ },
+ personality_index: u2,
+ has_lsda: u1,
+ start: u1,
+};
diff --git a/lib/std/os/linux.zig b/lib/std/os/linux.zig
@@ -86,6 +86,7 @@ pub const timeval = arch_bits.timeval;
pub const timezone = arch_bits.timezone;
pub const ucontext_t = arch_bits.ucontext_t;
pub const user_desc = arch_bits.user_desc;
+pub const getcontext = arch_bits.getcontext;
pub const tls = @import("linux/tls.zig");
pub const pie = @import("linux/start_pie.zig");
diff --git a/lib/std/os/linux/x86.zig b/lib/std/os/linux/x86.zig
@@ -389,3 +389,86 @@ pub const SC = struct {
pub const recvmmsg = 19;
pub const sendmmsg = 20;
};
+
+fn gpRegisterOffset(comptime reg_index: comptime_int) usize {
+ return @offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "gregs") + @sizeOf(usize) * reg_index;
+}
+
+noinline fn getContextReturnAddress() usize {
+ return @returnAddress();
+}
+
+pub fn getContextInternal() callconv(.Naked) void {
+ asm volatile (
+ \\ movl $0, (%[flags_offset])(%%edx)
+ \\ movl $0, (%[link_offset])(%%edx)
+ \\ movl %%edi, (%[edi_offset])(%%edx)
+ \\ movl %%esi, (%[esi_offset])(%%edx)
+ \\ movl %%ebp, (%[ebp_offset])(%%edx)
+ \\ movl %%ebx, (%[ebx_offset])(%%edx)
+ \\ movl %%edx, (%[edx_offset])(%%edx)
+ \\ movl %%ecx, (%[ecx_offset])(%%edx)
+ \\ movl %%eax, (%[eax_offset])(%%edx)
+ \\ movl (%%esp), %%ecx
+ \\ movl %%ecx, (%[eip_offset])(%%edx)
+ \\ leal 4(%%esp), %%ecx
+ \\ movl %%ecx, (%[esp_offset])(%%edx)
+ \\ xorl %%ecx, %%ecx
+ \\ movw %%fs, %%cx
+ \\ movl %%ecx, (%[fs_offset])(%%edx)
+ \\ leal (%[regspace_offset])(%%edx), %%ecx
+ \\ movl %%ecx, (%[fpregs_offset])(%%edx)
+ \\ fnstenv (%%ecx)
+ \\ fldenv (%%ecx)
+ \\ pushl %%ebx
+ \\ pushl %%esi
+ \\ xorl %%ebx, %%ebx
+ \\ movl %[sigaltstack], %%eax
+ \\ leal (%[stack_offset])(%%edx), %%ecx
+ \\ int $0x80
+ \\ cmpl $0, %%eax
+ \\ jne return
+ \\ movl %[sigprocmask], %%eax
+ \\ xorl %%ecx, %%ecx
+ \\ leal (%[sigmask_offset])(%%edx), %%edx
+ \\ movl %[sigset_size], %%esi
+ \\ int $0x80
+ \\ return:
+ \\ popl %%esi
+ \\ popl %%ebx
+ :
+ : [flags_offset] "p" (@offsetOf(ucontext_t, "flags")),
+ [link_offset] "p" (@offsetOf(ucontext_t, "link")),
+ [edi_offset] "p" (comptime gpRegisterOffset(REG.EDI)),
+ [esi_offset] "p" (comptime gpRegisterOffset(REG.ESI)),
+ [ebp_offset] "p" (comptime gpRegisterOffset(REG.EBP)),
+ [esp_offset] "p" (comptime gpRegisterOffset(REG.ESP)),
+ [ebx_offset] "p" (comptime gpRegisterOffset(REG.EBX)),
+ [edx_offset] "p" (comptime gpRegisterOffset(REG.EDX)),
+ [ecx_offset] "p" (comptime gpRegisterOffset(REG.ECX)),
+ [eax_offset] "p" (comptime gpRegisterOffset(REG.EAX)),
+ [eip_offset] "p" (comptime gpRegisterOffset(REG.EIP)),
+ [fs_offset] "p" (comptime gpRegisterOffset(REG.FS)),
+ [fpregs_offset] "p" (@offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "fpregs")),
+ [regspace_offset] "p" (@offsetOf(ucontext_t, "regspace")),
+ [sigaltstack] "i" (@intFromEnum(linux.SYS.sigaltstack)),
+ [stack_offset] "p" (@offsetOf(ucontext_t, "stack")),
+ [sigprocmask] "i" (@intFromEnum(linux.SYS.rt_sigprocmask)),
+ [sigmask_offset] "p" (@offsetOf(ucontext_t, "sigmask")),
+ [sigset_size] "i" (linux.NSIG / 8),
+ : "memory", "eax", "ecx", "edx"
+ );
+}
+
+pub inline fn getcontext(context: *ucontext_t) usize {
+ // This method is used so that getContextInternal can control
+ // its prologue in order to read ESP from a constant offset.
+ // The unused &getContextInternal input is required so the function is included in the binary.
+ return asm volatile (
+ \\ call os.linux.x86.getContextInternal
+ : [ret] "={eax}" (-> usize),
+ : [context] "{edx}" (context),
+ [getContextInternal] "X" (&getContextInternal),
+ : "memory", "ecx"
+ );
+}
diff --git a/lib/std/os/linux/x86_64.zig b/lib/std/os/linux/x86_64.zig
@@ -395,3 +395,97 @@ pub const ucontext_t = extern struct {
sigmask: sigset_t,
fpregs_mem: [64]usize,
};
+
+fn gpRegisterOffset(comptime reg_index: comptime_int) usize {
+ return @offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "gregs") + @sizeOf(usize) * reg_index;
+}
+
+fn getContextInternal() callconv(.Naked) void {
+ // TODO: Read GS/FS registers?
+ asm volatile (
+ \\ movq $0, (%[flags_offset])(%%rdi)
+ \\ movq $0, (%[link_offset])(%%rdi)
+ \\ movq %%r8, (%[r8_offset])(%%rdi)
+ \\ movq %%r9, (%[r9_offset])(%%rdi)
+ \\ movq %%r10, (%[r10_offset])(%%rdi)
+ \\ movq %%r11, (%[r11_offset])(%%rdi)
+ \\ movq %%r12, (%[r12_offset])(%%rdi)
+ \\ movq %%r13, (%[r13_offset])(%%rdi)
+ \\ movq %%r14, (%[r14_offset])(%%rdi)
+ \\ movq %%r15, (%[r15_offset])(%%rdi)
+ \\ movq %%rdi, (%[rdi_offset])(%%rdi)
+ \\ movq %%rsi, (%[rsi_offset])(%%rdi)
+ \\ movq %%rbp, (%[rbp_offset])(%%rdi)
+ \\ movq %%rbx, (%[rbx_offset])(%%rdi)
+ \\ movq %%rdx, (%[rdx_offset])(%%rdi)
+ \\ movq %%rax, (%[rax_offset])(%%rdi)
+ \\ movq %%rcx, (%[rcx_offset])(%%rdi)
+ \\ movq (%%rsp), %%rcx
+ \\ movq %%rcx, (%[rip_offset])(%%rdi)
+ \\ leaq 8(%%rsp), %%rcx
+ \\ movq %%rcx, (%[rsp_offset])(%%rdi)
+ \\ pushfq
+ \\ popq (%[efl_offset])(%%rdi)
+ \\ leaq (%[fpmem_offset])(%%rdi), %%rcx
+ \\ movq %%rcx, (%[fpstate_offset])(%%rdi)
+ \\ fnstenv (%%rcx)
+ \\ fldenv (%%rcx)
+ \\ stmxcsr (%[mxcsr_offset])(%%rdi)
+ \\ leaq (%[stack_offset])(%%rdi), %%rsi
+ \\ movq %%rdi, %%r8
+ \\ xorq %%rdi, %%rdi
+ \\ movq %[sigaltstack], %%rax
+ \\ syscall
+ \\ cmpq $0, %%rax
+ \\ jne return
+ \\ movq %[sigprocmask], %%rax
+ \\ xorq %%rsi, %%rsi
+ \\ leaq (%[sigmask_offset])(%%r8), %%rdx
+ \\ movq %[sigset_size], %%r10
+ \\ syscall
+ \\ return:
+ :
+ : [flags_offset] "p" (@offsetOf(ucontext_t, "flags")),
+ [link_offset] "p" (@offsetOf(ucontext_t, "link")),
+ [r8_offset] "p" (comptime gpRegisterOffset(REG.R8)),
+ [r9_offset] "p" (comptime gpRegisterOffset(REG.R9)),
+ [r10_offset] "p" (comptime gpRegisterOffset(REG.R10)),
+ [r11_offset] "p" (comptime gpRegisterOffset(REG.R11)),
+ [r12_offset] "p" (comptime gpRegisterOffset(REG.R12)),
+ [r13_offset] "p" (comptime gpRegisterOffset(REG.R13)),
+ [r14_offset] "p" (comptime gpRegisterOffset(REG.R14)),
+ [r15_offset] "p" (comptime gpRegisterOffset(REG.R15)),
+ [rdi_offset] "p" (comptime gpRegisterOffset(REG.RDI)),
+ [rsi_offset] "p" (comptime gpRegisterOffset(REG.RSI)),
+ [rbp_offset] "p" (comptime gpRegisterOffset(REG.RBP)),
+ [rbx_offset] "p" (comptime gpRegisterOffset(REG.RBX)),
+ [rdx_offset] "p" (comptime gpRegisterOffset(REG.RDX)),
+ [rax_offset] "p" (comptime gpRegisterOffset(REG.RAX)),
+ [rcx_offset] "p" (comptime gpRegisterOffset(REG.RCX)),
+ [rsp_offset] "p" (comptime gpRegisterOffset(REG.RSP)),
+ [rip_offset] "p" (comptime gpRegisterOffset(REG.RIP)),
+ [efl_offset] "p" (comptime gpRegisterOffset(REG.EFL)),
+ [fpstate_offset] "p" (@offsetOf(ucontext_t, "mcontext") + @offsetOf(mcontext_t, "fpregs")),
+ [fpmem_offset] "p" (@offsetOf(ucontext_t, "fpregs_mem")),
+ [mxcsr_offset] "p" (@offsetOf(ucontext_t, "fpregs_mem") + @offsetOf(fpstate, "mxcsr")),
+ [sigaltstack] "i" (@intFromEnum(linux.SYS.sigaltstack)),
+ [stack_offset] "p" (@offsetOf(ucontext_t, "stack")),
+ [sigprocmask] "i" (@intFromEnum(linux.SYS.rt_sigprocmask)),
+ [sigmask_offset] "p" (@offsetOf(ucontext_t, "sigmask")),
+ [sigset_size] "i" (linux.NSIG / 8),
+ : "memory", "rcx", "rdx", "rdi", "rsi", "r8", "r10", "r11"
+ );
+}
+
+pub inline fn getcontext(context: *ucontext_t) usize {
+ // This method is used so that getContextInternal can control
+ // its prologue in order to read RSP from a constant offset
+ // The unused &getContextInternal input is required so the function is included in the binary.
+ return asm volatile (
+ \\ call os.linux.x86_64.getContextInternal
+ : [ret] "={rax}" (-> usize),
+ : [context] "{rdi}" (context),
+ [getContextInternal] "X" (&getContextInternal),
+ : "memory", "rcx", "rdx", "rdi", "rsi", "r8", "r10", "r11"
+ );
+}
diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
@@ -3301,6 +3301,35 @@ pub const REGSAM = ACCESS_MASK;
pub const ACCESS_MASK = DWORD;
pub const LSTATUS = LONG;
+pub const SECTION_INHERIT = enum(c_int) {
+ ViewShare = 0,
+ ViewUnmap = 1,
+};
+
+pub const SECTION_QUERY = 0x0001;
+pub const SECTION_MAP_WRITE = 0x0002;
+pub const SECTION_MAP_READ = 0x0004;
+pub const SECTION_MAP_EXECUTE = 0x0008;
+pub const SECTION_EXTEND_SIZE = 0x0010;
+pub const SECTION_ALL_ACCESS =
+ STANDARD_RIGHTS_REQUIRED |
+ SECTION_QUERY |
+ SECTION_MAP_WRITE |
+ SECTION_MAP_READ |
+ SECTION_MAP_EXECUTE |
+ SECTION_EXTEND_SIZE;
+
+pub const SEC_64K_PAGES = 0x80000;
+pub const SEC_FILE = 0x800000;
+pub const SEC_IMAGE = 0x1000000;
+pub const SEC_PROTECTED_IMAGE = 0x2000000;
+pub const SEC_RESERVE = 0x4000000;
+pub const SEC_COMMIT = 0x8000000;
+pub const SEC_IMAGE_NO_EXECUTE = SEC_IMAGE | SEC_NOCACHE;
+pub const SEC_NOCACHE = 0x10000000;
+pub const SEC_WRITECOMBINE = 0x40000000;
+pub const SEC_LARGE_PAGES = 0x80000000;
+
pub const HKEY = *opaque {};
pub const HKEY_LOCAL_MACHINE: HKEY = @as(HKEY, @ptrFromInt(0x80000002));
diff --git a/lib/std/os/windows/ntdll.zig b/lib/std/os/windows/ntdll.zig
@@ -36,6 +36,7 @@ const THREADINFOCLASS = windows.THREADINFOCLASS;
const PROCESSINFOCLASS = windows.PROCESSINFOCLASS;
const LPVOID = windows.LPVOID;
const LPCVOID = windows.LPCVOID;
+const SECTION_INHERIT = windows.SECTION_INHERIT;
pub extern "ntdll" fn NtQueryInformationProcess(
ProcessHandle: HANDLE,
@@ -125,6 +126,31 @@ pub extern "ntdll" fn NtCreateFile(
EaBuffer: ?*anyopaque,
EaLength: ULONG,
) callconv(WINAPI) NTSTATUS;
+pub extern "ntdll" fn NtCreateSection(
+ SectionHandle: *HANDLE,
+ DesiredAccess: ACCESS_MASK,
+ ObjectAttributes: ?*OBJECT_ATTRIBUTES,
+ MaximumSize: ?*LARGE_INTEGER,
+ SectionPageProtection: ULONG,
+ AllocationAttributes: ULONG,
+ FileHandle: ?HANDLE,
+) callconv(WINAPI) NTSTATUS;
+pub extern "ntdll" fn NtMapViewOfSection(
+ SectionHandle: HANDLE,
+ ProcessHandle: HANDLE,
+ BaseAddress: *PVOID,
+ ZeroBits: ?*ULONG,
+ CommitSize: SIZE_T,
+ SectionOffset: ?*LARGE_INTEGER,
+ ViewSize: *SIZE_T,
+ InheritDispostion: SECTION_INHERIT,
+ AllocationType: ULONG,
+ Win32Protect: ULONG,
+) callconv(WINAPI) NTSTATUS;
+pub extern "ntdll" fn NtUnmapViewOfSection(
+ ProcessHandle: HANDLE,
+ BaseAddress: PVOID,
+) callconv(WINAPI) NTSTATUS;
pub extern "ntdll" fn NtDeviceIoControlFile(
FileHandle: HANDLE,
Event: ?HANDLE,
diff --git a/src/Compilation.zig b/src/Compilation.zig
@@ -5288,6 +5288,7 @@ pub fn generateBuiltinZigSource(comp: *Compilation, allocator: Allocator) Alloca
\\pub const position_independent_executable = {};
\\pub const strip_debug_info = {};
\\pub const code_model = std.builtin.CodeModel.{};
+ \\pub const omit_frame_pointer = {};
\\
, .{
std.zig.fmtId(@tagName(target.ofmt)),
@@ -5301,6 +5302,7 @@ pub fn generateBuiltinZigSource(comp: *Compilation, allocator: Allocator) Alloca
comp.bin_file.options.pie,
comp.bin_file.options.strip,
std.zig.fmtId(@tagName(comp.bin_file.options.machine_code_model)),
+ comp.bin_file.options.omit_frame_pointer,
});
if (target.os.tag == .wasi) {
diff --git a/src/crash_report.zig b/src/crash_report.zig
@@ -203,53 +203,11 @@ fn handleSegfaultPosix(sig: i32, info: *const os.siginfo_t, ctx_ptr: ?*const any
};
const stack_ctx: StackContext = switch (builtin.cpu.arch) {
- .x86 => ctx: {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = @as(usize, @intCast(ctx.mcontext.gregs[os.REG.EIP]));
- const bp = @as(usize, @intCast(ctx.mcontext.gregs[os.REG.EBP]));
- break :ctx StackContext{ .exception = .{ .bp = bp, .ip = ip } };
- },
- .x86_64 => ctx: {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = switch (builtin.os.tag) {
- .linux, .netbsd, .solaris => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.RIP])),
- .freebsd => @as(usize, @intCast(ctx.mcontext.rip)),
- .openbsd => @as(usize, @intCast(ctx.sc_rip)),
- .macos => @as(usize, @intCast(ctx.mcontext.ss.rip)),
- else => unreachable,
- };
- const bp = switch (builtin.os.tag) {
- .linux, .netbsd, .solaris => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.RBP])),
- .openbsd => @as(usize, @intCast(ctx.sc_rbp)),
- .freebsd => @as(usize, @intCast(ctx.mcontext.rbp)),
- .macos => @as(usize, @intCast(ctx.mcontext.ss.rbp)),
- else => unreachable,
- };
- break :ctx StackContext{ .exception = .{ .bp = bp, .ip = ip } };
- },
- .arm => ctx: {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = @as(usize, @intCast(ctx.mcontext.arm_pc));
- const bp = @as(usize, @intCast(ctx.mcontext.arm_fp));
- break :ctx StackContext{ .exception = .{ .bp = bp, .ip = ip } };
- },
- .aarch64 => ctx: {
- const ctx: *const os.ucontext_t = @ptrCast(@alignCast(ctx_ptr));
- const ip = switch (native_os) {
- .macos => @as(usize, @intCast(ctx.mcontext.ss.pc)),
- .netbsd => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.PC])),
- .freebsd => @as(usize, @intCast(ctx.mcontext.gpregs.elr)),
- else => @as(usize, @intCast(ctx.mcontext.pc)),
- };
- // x29 is the ABI-designated frame pointer
- const bp = switch (native_os) {
- .macos => @as(usize, @intCast(ctx.mcontext.ss.fp)),
- .netbsd => @as(usize, @intCast(ctx.mcontext.gregs[os.REG.FP])),
- .freebsd => @as(usize, @intCast(ctx.mcontext.gpregs.x[os.REG.FP])),
- else => @as(usize, @intCast(ctx.mcontext.regs[29])),
- };
- break :ctx StackContext{ .exception = .{ .bp = bp, .ip = ip } };
- },
+ .x86,
+ .x86_64,
+ .arm,
+ .aarch64,
+ => StackContext{ .exception = @ptrCast(@alignCast(ctx_ptr)) },
else => .not_supported,
};
@@ -275,10 +233,9 @@ fn handleSegfaultWindows(info: *os.windows.EXCEPTION_POINTERS) callconv(os.windo
fn handleSegfaultWindowsExtra(info: *os.windows.EXCEPTION_POINTERS, comptime msg: WindowsSegfaultMessage) noreturn {
PanicSwitch.preDispatch();
- const stack_ctx = if (@hasDecl(os.windows, "CONTEXT")) ctx: {
- const regs = info.ContextRecord.getRegs();
- break :ctx StackContext{ .exception = .{ .bp = regs.bp, .ip = regs.ip } };
- } else ctx: {
+ const stack_ctx = if (@hasDecl(os.windows, "CONTEXT"))
+ StackContext{ .exception = info.ContextRecord }
+ else ctx: {
const addr = @intFromPtr(info.ExceptionRecord.ExceptionAddress);
break :ctx StackContext{ .current = .{ .ret_addr = addr } };
};
@@ -293,7 +250,7 @@ fn handleSegfaultWindowsExtra(info: *os.windows.EXCEPTION_POINTERS, comptime msg
},
.illegal_instruction => {
const ip: ?usize = switch (stack_ctx) {
- .exception => |ex| ex.ip,
+ .exception => |ex| ex.getRegs().ip,
.current => |cur| cur.ret_addr,
.not_supported => null,
};
@@ -314,10 +271,7 @@ const StackContext = union(enum) {
current: struct {
ret_addr: ?usize,
},
- exception: struct {
- bp: usize,
- ip: usize,
- },
+ exception: *const debug.ThreadContext,
not_supported: void,
pub fn dumpStackTrace(ctx: @This()) void {
@@ -325,8 +279,8 @@ const StackContext = union(enum) {
.current => |ct| {
debug.dumpCurrentStackTrace(ct.ret_addr);
},
- .exception => |ex| {
- debug.dumpStackTraceFromBase(ex.bp, ex.ip);
+ .exception => |context| {
+ debug.dumpStackTraceFromBase(context);
},
.not_supported => {
const stderr = io.getStdErr().writer();
diff --git a/src/target.zig b/src/target.zig
@@ -510,7 +510,7 @@ pub fn clangAssemblerSupportsMcpuArg(target: std.Target) bool {
}
pub fn needUnwindTables(target: std.Target) bool {
- return target.os.tag == .windows;
+ return target.os.tag == .windows or target.isDarwin();
}
pub fn defaultAddressSpace(
diff --git a/test/standalone.zig b/test/standalone.zig
@@ -230,6 +230,14 @@ pub const build_cases = [_]BuildCase{
.build_root = "test/standalone/zerolength_check",
.import = @import("standalone/zerolength_check/build.zig"),
},
+ .{
+ .build_root = "test/standalone/stack_iterator",
+ .import = @import("standalone/stack_iterator/build.zig"),
+ },
+ .{
+ .build_root = "test/standalone/coff_dwarf",
+ .import = @import("standalone/coff_dwarf/build.zig"),
+ },
};
const std = @import("std");
diff --git a/test/standalone/coff_dwarf/build.zig b/test/standalone/coff_dwarf/build.zig
@@ -0,0 +1,35 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+/// This tests the path where DWARF information is embedded in a COFF binary
+pub fn build(b: *std.Build) void {
+ const test_step = b.step("test", "Test it");
+ b.default_step = test_step;
+
+ const optimize: std.builtin.OptimizeMode = .Debug;
+ const target = b.standardTargetOptions(.{});
+
+ if (builtin.os.tag != .windows) return;
+
+ const exe = b.addExecutable(.{
+ .name = "main",
+ .root_source_file = .{ .path = "main.zig" },
+ .optimize = optimize,
+ .target = target,
+ });
+
+ const lib = b.addSharedLibrary(.{
+ .name = "shared_lib",
+ .optimize = optimize,
+ .target = target,
+ });
+ lib.addCSourceFile("shared_lib.c", &.{"-gdwarf"});
+ lib.linkLibC();
+ exe.linkLibrary(lib);
+
+ const run = b.addRunArtifact(exe);
+ run.expectExitCode(0);
+ run.skip_foreign_checks = true;
+
+ test_step.dependOn(&run.step);
+}
diff --git a/test/standalone/coff_dwarf/main.zig b/test/standalone/coff_dwarf/main.zig
@@ -0,0 +1,27 @@
+const std = @import("std");
+const assert = std.debug.assert;
+const testing = std.testing;
+
+extern fn add(a: u32, b: u32, addr: *usize) u32;
+
+pub fn main() !void {
+ var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+ defer assert(gpa.deinit() == .ok);
+ const allocator = gpa.allocator();
+
+ var debug_info = try std.debug.openSelfDebugInfo(allocator);
+ defer debug_info.deinit();
+
+ var add_addr: usize = undefined;
+ _ = add(1, 2, &add_addr);
+
+ const module = try debug_info.getModuleForAddress(add_addr);
+ const symbol = try module.getSymbolAtAddress(allocator, add_addr);
+ defer symbol.deinit(allocator);
+
+ try testing.expectEqualStrings("add", symbol.symbol_name);
+ try testing.expect(symbol.line_info != null);
+ try testing.expectEqualStrings("shared_lib.c", std.fs.path.basename(symbol.line_info.?.file_name));
+ try testing.expectEqual(@as(u64, 3), symbol.line_info.?.line);
+ try testing.expectEqual(@as(u64, 0), symbol.line_info.?.column);
+}
diff --git a/test/standalone/coff_dwarf/shared_lib.c b/test/standalone/coff_dwarf/shared_lib.c
@@ -0,0 +1,6 @@
+#include <stdint.h>
+
+__declspec(dllexport) uint32_t add(uint32_t a, uint32_t b, uintptr_t* addr) {
+ *addr = (uintptr_t)&add;
+ return a + b;
+}
diff --git a/test/standalone/stack_iterator/build.zig b/test/standalone/stack_iterator/build.zig
@@ -0,0 +1,94 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+ const test_step = b.step("test", "Test it");
+ b.default_step = test_step;
+
+ const target = b.standardTargetOptions(.{});
+ const optimize = b.standardOptimizeOption(.{});
+
+ // Unwinding with a frame pointer
+ //
+ // getcontext version: zig std
+ //
+ // Unwind info type:
+ // - ELF: DWARF .debug_frame
+ // - MachO: __unwind_info encodings:
+ // - x86_64: RBP_FRAME
+ // - aarch64: FRAME, DWARF
+ {
+ const exe = b.addExecutable(.{
+ .name = "unwind_fp",
+ .root_source_file = .{ .path = "unwind.zig" },
+ .target = target,
+ .optimize = optimize,
+ });
+
+ if (target.isDarwin()) exe.unwind_tables = true;
+ exe.omit_frame_pointer = false;
+
+ const run_cmd = b.addRunArtifact(exe);
+ test_step.dependOn(&run_cmd.step);
+ }
+
+ // Unwinding without a frame pointer
+ //
+ // getcontext version: zig std
+ //
+ // Unwind info type:
+ // - ELF: DWARF .eh_frame_hdr + .eh_frame
+ // - MachO: __unwind_info encodings:
+ // - x86_64: STACK_IMMD, STACK_IND
+ // - aarch64: FRAMELESS, DWARF
+ {
+ const exe = b.addExecutable(.{
+ .name = "unwind_nofp",
+ .root_source_file = .{ .path = "unwind.zig" },
+ .target = target,
+ .optimize = optimize,
+ });
+
+ exe.omit_frame_pointer = true;
+ exe.unwind_tables = true;
+
+ const run_cmd = b.addRunArtifact(exe);
+ test_step.dependOn(&run_cmd.step);
+ }
+
+ // Unwinding through a C shared library without a frame pointer (libc)
+ //
+ // getcontext version: libc
+ //
+ // Unwind info type:
+ // - ELF: DWARF .eh_frame + .debug_frame
+ // - MachO: __unwind_info encodings:
+ // - x86_64: STACK_IMMD, STACK_IND
+ // - aarch64: FRAMELESS, DWARF
+ {
+ const c_shared_lib = b.addSharedLibrary(.{
+ .name = "c_shared_lib",
+ .target = target,
+ .optimize = optimize,
+ });
+
+ if (target.isWindows()) c_shared_lib.defineCMacro("LIB_API", "__declspec(dllexport)");
+
+ c_shared_lib.strip = false;
+ c_shared_lib.addCSourceFile("shared_lib.c", &.{"-fomit-frame-pointer"});
+ c_shared_lib.linkLibC();
+
+ const exe = b.addExecutable(.{
+ .name = "shared_lib_unwind",
+ .root_source_file = .{ .path = "shared_lib_unwind.zig" },
+ .target = target,
+ .optimize = optimize,
+ });
+
+ if (target.isDarwin()) exe.unwind_tables = true;
+ exe.omit_frame_pointer = true;
+ exe.linkLibrary(c_shared_lib);
+
+ const run_cmd = b.addRunArtifact(exe);
+ test_step.dependOn(&run_cmd.step);
+ }
+}
diff --git a/test/standalone/stack_iterator/shared_lib.c b/test/standalone/stack_iterator/shared_lib.c
@@ -0,0 +1,22 @@
+#include <stdint.h>
+
+#ifndef LIB_API
+#define LIB_API
+#endif
+
+__attribute__((noinline)) void frame1(
+ void** expected,
+ void** unwound,
+ void (*frame2)(void** expected, void** unwound)) {
+ expected[3] = __builtin_extract_return_addr(__builtin_return_address(0));
+ frame2(expected, unwound);
+}
+
+LIB_API void frame0(
+ void** expected,
+ void** unwound,
+ void (*frame2)(void** expected, void** unwound)) {
+ expected[4] = __builtin_extract_return_addr(__builtin_return_address(0));
+ frame1(expected, unwound, frame2);
+}
+
diff --git a/test/standalone/stack_iterator/shared_lib_unwind.zig b/test/standalone/stack_iterator/shared_lib_unwind.zig
@@ -0,0 +1,47 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const debug = std.debug;
+const testing = std.testing;
+
+noinline fn frame4(expected: *[5]usize, unwound: *[5]usize) void {
+ expected[0] = @returnAddress();
+
+ var context: debug.ThreadContext = undefined;
+ testing.expect(debug.getContext(&context)) catch @panic("failed to getContext");
+
+ var debug_info = debug.getSelfDebugInfo() catch @panic("failed to openSelfDebugInfo");
+ var it = debug.StackIterator.initWithContext(expected[0], debug_info, &context) catch @panic("failed to initWithContext");
+ defer it.deinit();
+
+ for (unwound) |*addr| {
+ if (it.next()) |return_address| addr.* = return_address;
+ }
+}
+
+noinline fn frame3(expected: *[5]usize, unwound: *[5]usize) void {
+ expected[1] = @returnAddress();
+ frame4(expected, unwound);
+}
+
+fn frame2(expected: *[5]usize, unwound: *[5]usize) callconv(.C) void {
+ expected[2] = @returnAddress();
+ frame3(expected, unwound);
+}
+
+extern fn frame0(
+ expected: *[5]usize,
+ unwound: *[5]usize,
+ frame_2: *const fn (expected: *[5]usize, unwound: *[5]usize) callconv(.C) void,
+) void;
+
+pub fn main() !void {
+ // Disabled until the DWARF unwinder bugs on .aarch64 are solved
+ if (builtin.omit_frame_pointer and comptime builtin.target.isDarwin() and builtin.cpu.arch == .aarch64) return;
+
+ if (!std.debug.have_ucontext or !std.debug.have_getcontext) return;
+
+ var expected: [5]usize = undefined;
+ var unwound: [5]usize = undefined;
+ frame0(&expected, &unwound, &frame2);
+ try testing.expectEqual(expected, unwound);
+}
diff --git a/test/standalone/stack_iterator/unwind.zig b/test/standalone/stack_iterator/unwind.zig
@@ -0,0 +1,99 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const debug = std.debug;
+const testing = std.testing;
+
+noinline fn frame3(expected: *[4]usize, unwound: *[4]usize) void {
+ expected[0] = @returnAddress();
+
+ var context: debug.ThreadContext = undefined;
+ testing.expect(debug.getContext(&context)) catch @panic("failed to getContext");
+
+ var debug_info = debug.getSelfDebugInfo() catch @panic("failed to openSelfDebugInfo");
+ var it = debug.StackIterator.initWithContext(expected[0], debug_info, &context) catch @panic("failed to initWithContext");
+ defer it.deinit();
+
+ for (unwound) |*addr| {
+ if (it.next()) |return_address| addr.* = return_address;
+ }
+}
+
+noinline fn frame2(expected: *[4]usize, unwound: *[4]usize) void {
+ // Excercise different __unwind_info / DWARF CFI encodings by forcing some registers to be restored
+ if (builtin.target.ofmt != .c) {
+ switch (builtin.cpu.arch) {
+ .x86 => {
+ if (builtin.omit_frame_pointer) {
+ asm volatile (
+ \\movl $3, %%ebx
+ \\movl $1, %%ecx
+ \\movl $2, %%edx
+ \\movl $7, %%edi
+ \\movl $6, %%esi
+ \\movl $5, %%ebp
+ ::: "ebx", "ecx", "edx", "edi", "esi", "ebp");
+ } else {
+ asm volatile (
+ \\movl $3, %%ebx
+ \\movl $1, %%ecx
+ \\movl $2, %%edx
+ \\movl $7, %%edi
+ \\movl $6, %%esi
+ ::: "ebx", "ecx", "edx", "edi", "esi");
+ }
+ },
+ .x86_64 => {
+ if (builtin.omit_frame_pointer) {
+ asm volatile (
+ \\movq $3, %%rbx
+ \\movq $12, %%r12
+ \\movq $13, %%r13
+ \\movq $14, %%r14
+ \\movq $15, %%r15
+ \\movq $6, %%rbp
+ ::: "rbx", "r12", "r13", "r14", "r15", "rbp");
+ } else {
+ asm volatile (
+ \\movq $3, %%rbx
+ \\movq $12, %%r12
+ \\movq $13, %%r13
+ \\movq $14, %%r14
+ \\movq $15, %%r15
+ ::: "rbx", "r12", "r13", "r14", "r15");
+ }
+ },
+ else => {},
+ }
+ }
+
+ expected[1] = @returnAddress();
+ frame3(expected, unwound);
+}
+
+noinline fn frame1(expected: *[4]usize, unwound: *[4]usize) void {
+ expected[2] = @returnAddress();
+
+ // Use a stack frame that is too big to encode in __unwind_info's stack-immediate encoding
+ // to exercise the stack-indirect encoding path
+ var pad: [std.math.maxInt(u8) * @sizeOf(usize) + 1]u8 = undefined;
+ _ = pad;
+
+ frame2(expected, unwound);
+}
+
+noinline fn frame0(expected: *[4]usize, unwound: *[4]usize) void {
+ expected[3] = @returnAddress();
+ frame1(expected, unwound);
+}
+
+pub fn main() !void {
+ // Disabled until the DWARF unwinder bugs on .aarch64 are solved
+ if (builtin.omit_frame_pointer and comptime builtin.target.isDarwin() and builtin.cpu.arch == .aarch64) return;
+
+ if (!std.debug.have_ucontext or !std.debug.have_getcontext) return;
+
+ var expected: [4]usize = undefined;
+ var unwound: [4]usize = undefined;
+ frame0(&expected, &unwound);
+ try testing.expectEqual(expected, unwound);
+}
