1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
/// Test StackIterator on 'freestanding' target. Based on unwind.zig.
const std = @import("std");
const builtin = @import("builtin");
const debug = std.debug;
noinline fn frame3(expected: *[4]usize, unwound: *[4]usize) void {
expected[0] = @returnAddress();
var it = debug.StackIterator.init(@returnAddress(), @frameAddress());
defer it.deinit();
// Save StackIterator's frame addresses into `unwound`:
for (unwound) |*addr| {
if (it.next()) |return_address| addr.* = return_address;
}
}
noinline fn frame2(expected: *[4]usize, unwound: *[4]usize) void {
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;
_ = std.mem.doNotOptimizeAway(&pad);
frame2(expected, unwound);
}
noinline fn frame0(expected: *[4]usize, unwound: *[4]usize) void {
expected[3] = @returnAddress();
frame1(expected, unwound);
}
// No-OS entrypoint
export fn _start() callconv(.c) noreturn {
var expected: [4]usize = undefined;
var unwound: [4]usize = undefined;
frame0(&expected, &unwound);
// Verify result (no std.testing in freestanding)
var missed: c_int = 0;
for (expected, unwound) |expectFA, actualFA| {
if (expectFA != actualFA) {
missed += 1;
}
}
// Need to compile with the target OS as "freestanding" or "other" to
// exercise the StackIterator code, but when run as a regression test
// need to actually exit. So assume we're running on x86_64-linux ...
asm volatile (
\\movl $60, %%eax
\\syscall
:
: [missed] "{edi}" (missed),
: .{ .edi = true, .eax = true });
while (true) {} // unreached
}
|
