commit d5db02728ce3ff3ba74a3e3f9050c3ea9ed34752 (tree)
parent 5cfcb015033864c769235726975ab9919c217ef9
Author: Alex Rønne Petersen <alex@alexrp.com>
Date: Mon, 20 Jan 2025 07:24:12 +0100
Merge pull request #22530 from alexrp/omit-unwind-tables
Fix building the standard library without CFI directives
Diffstat:
18 files changed, 147 insertions(+), 8 deletions(-)
diff --git a/lib/std/os/linux/aarch64.zig b/lib/std/os/linux/aarch64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -122,7 +123,12 @@ pub fn clone() callconv(.Naked) usize {
\\ ret
\\
\\ // child
- \\1: .cfi_undefined lr
+ \\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+ \\ .cfi_undefined lr
+ );
+ asm volatile (
\\ mov fp, 0
\\ mov lr, 0
\\
diff --git a/lib/std/os/linux/hexagon.zig b/lib/std/os/linux/hexagon.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const iovec = std.posix.iovec;
const iovec_const = std.posix.iovec_const;
@@ -117,8 +118,11 @@ pub fn clone() callconv(.Naked) usize {
\\
\\ p0 = cmp.eq(r0, #0)
\\ if (!p0) dealloc_return
- \\
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined r31
+ );
+ asm volatile (
\\ r30 = #0
\\ r31 = #0
\\
diff --git a/lib/std/os/linux/loongarch64.zig b/lib/std/os/linux/loongarch64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const linux = std.os.linux;
const SYS = linux.SYS;
@@ -121,7 +122,11 @@ pub fn clone() callconv(.Naked) usize {
\\ beqz $a0, 1f # whether child process
\\ jirl $zero, $ra, 0 # parent process return
\\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined 1
+ );
+ asm volatile (
\\ move $fp, $zero
\\ move $ra, $zero
\\
diff --git a/lib/std/os/linux/mips.zig b/lib/std/os/linux/mips.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -231,7 +232,11 @@ pub fn clone() callconv(.Naked) usize {
\\ jr $ra
\\ nop
\\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined $ra
+ );
+ asm volatile (
\\ move $fp, $zero
\\ move $ra, $zero
\\
diff --git a/lib/std/os/linux/mips64.zig b/lib/std/os/linux/mips64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -210,7 +211,11 @@ pub fn clone() callconv(.Naked) usize {
\\ jr $ra
\\ nop
\\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined $ra
+ );
+ asm volatile (
\\ move $fp, $zero
\\ move $ra, $zero
\\
diff --git a/lib/std/os/linux/powerpc.zig b/lib/std/os/linux/powerpc.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -176,7 +177,11 @@ pub fn clone() callconv(.Naked) usize {
\\
\\ #else: we're the child
\\ 2:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined lr
+ );
+ asm volatile (
\\ li 31, 0
\\ mtlr 0
\\
diff --git a/lib/std/os/linux/powerpc64.zig b/lib/std/os/linux/powerpc64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -161,7 +162,11 @@ pub fn clone() callconv(.Naked) usize {
\\ bnelr cr7
\\
\\ # we're the child
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined lr
+ );
+ asm volatile (
\\ li 31, 0
\\ mtlr 0
\\
diff --git a/lib/std/os/linux/riscv32.zig b/lib/std/os/linux/riscv32.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const iovec = std.posix.iovec;
const iovec_const = std.posix.iovec_const;
@@ -120,7 +121,12 @@ pub fn clone() callconv(.Naked) usize {
\\ ret
\\
\\ # Child
- \\1: .cfi_undefined ra
+ \\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+ \\ .cfi_undefined ra
+ );
+ asm volatile (
\\ mv fp, zero
\\ mv ra, zero
\\
diff --git a/lib/std/os/linux/riscv64.zig b/lib/std/os/linux/riscv64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const iovec = std.posix.iovec;
const iovec_const = std.posix.iovec_const;
@@ -120,7 +121,12 @@ pub fn clone() callconv(.Naked) usize {
\\ ret
\\
\\ # Child
- \\1: .cfi_undefined ra
+ \\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+ \\ .cfi_undefined ra
+ );
+ asm volatile (
\\ mv fp, zero
\\ mv ra, zero
\\
diff --git a/lib/std/os/linux/s390x.zig b/lib/std/os/linux/s390x.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const iovec = std.posix.iovec;
const iovec_const = std.posix.iovec_const;
@@ -134,7 +135,11 @@ pub fn clone() callconv(.Naked) usize {
\\bnzr %%r14
\\
\\# we're the child
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\.cfi_undefined %%r14
+ );
+ asm volatile (
\\lghi %%r11, 0
\\lghi %%r14, 0
\\
diff --git a/lib/std/os/linux/sparc64.zig b/lib/std/os/linux/sparc64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const pid_t = linux.pid_t;
@@ -215,7 +216,11 @@ pub fn clone() callconv(.Naked) usize {
\\ restore
\\2:
\\ # Child process
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined %%i7
+ );
+ asm volatile (
\\ mov %%g0, %%fp
\\ mov %%g0, %%i7
\\
diff --git a/lib/std/os/linux/x86.zig b/lib/std/os/linux/x86.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -156,7 +157,11 @@ pub fn clone() callconv(.Naked) usize {
\\ retl
\\
\\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
\\ .cfi_undefined %%eip
+ );
+ asm volatile (
\\ xorl %%ebp,%%ebp
\\
\\ popl %%eax
diff --git a/lib/std/os/linux/x86_64.zig b/lib/std/os/linux/x86_64.zig
@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
const std = @import("../../std.zig");
const maxInt = std.math.maxInt;
const linux = std.os.linux;
@@ -117,7 +118,12 @@ pub fn clone() callconv(.Naked) usize {
\\ jz 1f
\\ retq
\\
- \\1: .cfi_undefined %%rip
+ \\1:
+ );
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+ \\ .cfi_undefined %%rip
+ );
+ asm volatile (
\\ xorl %%ebp,%%ebp
\\
\\ popq %%rdi
diff --git a/lib/std/start.zig b/lib/std/start.zig
@@ -231,8 +231,8 @@ fn _start() callconv(.naked) noreturn {
}
// This is the first userspace frame. Prevent DWARF-based unwinders from unwinding further. We
- // prevent FP-based unwinders from unwinding further by zeroing the register further below.
- asm volatile (switch (native_arch) {
+ // prevent FP-based unwinders from unwinding further by zeroing the register below.
+ if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (switch (native_arch) {
.arc => ".cfi_undefined blink",
.arm, .armeb, .thumb, .thumbeb => "", // https://github.com/llvm/llvm-project/issues/115891
.aarch64, .aarch64_be => ".cfi_undefined lr",
diff --git a/src/Package/Module.zig b/src/Package/Module.zig
@@ -387,7 +387,7 @@ pub fn create(arena: Allocator, options: CreateOptions) !*Package.Module {
.zig_backend = zig_backend,
.output_mode = options.global.output_mode,
.link_mode = options.global.link_mode,
- .unwind_tables = options.global.any_unwind_tables,
+ .unwind_tables = unwind_tables,
.is_test = options.global.is_test,
.single_threaded = single_threaded,
.link_libc = options.global.link_libc,
diff --git a/test/standalone/build.zig.zon b/test/standalone/build.zig.zon
@@ -183,6 +183,9 @@
.empty_global_error_set = .{
.path = "empty_global_error_set",
},
+ .omit_cfi = .{
+ .path = "omit_cfi",
+ },
},
.paths = .{
"build.zig",
diff --git a/test/standalone/omit_cfi/build.zig b/test/standalone/omit_cfi/build.zig
@@ -0,0 +1,67 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+ inline for (.{
+ .aarch64,
+ .aarch64_be,
+ .hexagon,
+ .loongarch64,
+ .mips,
+ .mipsel,
+ .mips64,
+ .mips64el,
+ .powerpc,
+ .powerpcle,
+ .powerpc64,
+ .powerpc64le,
+ .riscv32,
+ .riscv64,
+ .s390x,
+ .sparc64,
+ .x86,
+ .x86_64,
+ }) |arch| {
+ const target = b.resolveTargetQuery(.{
+ .cpu_arch = arch,
+ .os_tag = .linux,
+ });
+
+ const omit_dbg = b.addExecutable(.{
+ .name = b.fmt("{s}-linux-omit-dbg", .{@tagName(arch)}),
+ .root_module = b.createModule(.{
+ .root_source_file = b.path("main.zig"),
+ .target = target,
+ .optimize = .Debug,
+ // We are mainly concerned with CFI directives in our non-libc startup code and syscall
+ // code, so make it explicit that we don't want libc.
+ .link_libc = false,
+ .strip = true,
+ }),
+ });
+
+ const omit_uwt = b.addExecutable(.{
+ .name = b.fmt("{s}-linux-omit-uwt", .{@tagName(arch)}),
+ .root_module = b.createModule(.{
+ .root_source_file = b.path("main.zig"),
+ .target = target,
+ .optimize = .Debug,
+ .link_libc = false,
+ .unwind_tables = .none,
+ }),
+ });
+
+ const omit_both = b.addExecutable(.{
+ .name = b.fmt("{s}-linux-omit-both", .{@tagName(arch)}),
+ .root_module = b.createModule(.{
+ .root_source_file = b.path("main.zig"),
+ .target = target,
+ .optimize = .Debug,
+ .link_libc = false,
+ .strip = true,
+ .unwind_tables = .none,
+ }),
+ });
+
+ inline for (.{ omit_dbg, omit_uwt, omit_both }) |step| b.installArtifact(step);
+ }
+}
diff --git a/test/standalone/omit_cfi/main.zig b/test/standalone/omit_cfi/main.zig
@@ -0,0 +1 @@
+pub fn main() void {}
