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
65
66
67
68
69
|
const builtin = @import("builtin");
const std = @import("std");
const expect = std.testing.expect;
var base: usize = undefined;
var result_off: [7]usize = undefined;
var result_len: [7]usize = undefined;
var result_index: usize = 0;
noinline fn insertionSort(data: []u64) void {
result_off[result_index] = @intFromPtr(data.ptr) - base;
result_len[result_index] = data.len;
result_index += 1;
if (data.len > 1) {
var least_i: usize = 0;
var i: usize = 1;
while (i < data.len) : (i += 1) {
if (data[i] < data[least_i])
least_i = i;
}
std.mem.swap(u64, &data[0], &data[least_i]);
// there used to be a bug where
// `data[1..]` is created on the stack
// and pointed to by the first argument register
// then stack is invalidated by the tailcall and
// overwritten by callee
// https://github.com/ziglang/zig/issues/9703
return @call(.always_tail, insertionSort, .{data[1..]});
}
}
test "arguments pointed to on stack into tailcall" {
switch (builtin.cpu.arch) {
.wasm32,
.mips,
.mipsel,
.mips64,
.mips64el,
.powerpc,
.powerpcle,
.powerpc64,
.powerpc64le,
=> return error.SkipZigTest,
else => {},
}
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
var data = [_]u64{ 1, 6, 2, 7, 1, 9, 3 };
base = @intFromPtr(&data);
insertionSort(data[0..]);
try expect(result_len[0] == 7);
try expect(result_len[1] == 6);
try expect(result_len[2] == 5);
try expect(result_len[3] == 4);
try expect(result_len[4] == 3);
try expect(result_len[5] == 2);
try expect(result_len[6] == 1);
try expect(result_off[0] == 0);
try expect(result_off[1] == 8);
try expect(result_off[2] == 16);
try expect(result_off[3] == 24);
try expect(result_off[4] == 32);
try expect(result_off[5] == 40);
try expect(result_off[6] == 48);
}
|
