compilation: pass omit_frame_pointer through to builtin.zig

Renamed dwarf_unwinding -> stack_iterator to better reflect that it's not just DWARF unwinding. Added a test for unwinding with a frame pointer.
2023-07-13 01:14:31 -04:00
parent 7d8b423477
commit ec96095efd
7 changed files with 60 additions and 22 deletions
--- a/test/standalone/stack_iterator/zig_unwind.zig
+++ b/test/standalone/stack_iterator/zig_unwind.zig
@@ -0,0 +1,96 @@
+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 {
+    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);
+}