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stage1: Fix asyncCall with non-abi-aligned arguments

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Make the code used to calculate the variable slot index into the frame
match what's done during the structure layout calculation.

Prevents a few nasty LLVM errors when such types are passed around.
This commit is contained in:
LemonBoy 2020-11-16 17:55:02 +01:00 committed by Andrew Kelley
parent eea4cd2924
commit 1c8cd268be
2 changed files with 35 additions and 6 deletions
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22
src/stage1/codegen.cpp
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@ -242,14 +242,24 @@ struct CalcLLVMFieldIndex {
static void calc_llvm_field_index_add(CodeGen *g, CalcLLVMFieldIndex *calc, ZigType *ty) {
if (!type_has_bits(g, ty)) return;
uint32_t ty_align = get_abi_alignment(g, ty);
if (calc->offset % ty_align != 0) {
uint32_t llvm_align = LLVMABIAlignmentOfType(g->target_data_ref, get_llvm_type(g, ty));
if (llvm_align >= ty_align) {
ty_align = llvm_align; // llvm's padding is sufficient
} else if (calc->offset) {
calc->field_index += 1; // zig will insert an extra padding field here
}
calc->offset += ty_align - (calc->offset % ty_align); // padding bytes
// Alignment according to Zig.
uint32_t adj_offset = calc->offset + (ty_align - (calc->offset % ty_align));
// Alignment according to LLVM.
uint32_t adj_llvm_offset = (calc->offset % llvm_align) ?
calc->offset + (llvm_align - (calc->offset % llvm_align)) :
calc->offset;
// Cannot under-align structure fields.
assert(adj_offset >= adj_llvm_offset);
// Zig will insert an extra padding field here.
if (adj_offset != adj_llvm_offset)
calc->field_index += 1;
calc->offset = adj_offset;
}
calc->offset += ty->abi_size;
calc->field_index += 1;

19
test/stage1/behavior/async_fn.zig
View File

@ -1589,3 +1589,22 @@ test "@asyncCall with pass-by-value arguments" {
F2,
});
}
test "@asyncCall with arguments having non-standard alignment" {
const F0: u64 = 0xbeefbeef;
const F1: u64 = 0xf00df00df00df00d;
const S = struct {
pub fn f(_fill0: u32, s: struct { x: u64 align(16) }, _fill1: u64) callconv(.Async) void {
// The compiler inserts extra alignment for s, check that the
// generated code picks the right slot for fill1.
expectEqual(F0, _fill0);
expectEqual(F1, _fill1);
}
};
var buffer: [1024]u8 align(@alignOf(@Frame(S.f))) = undefined;
// The function pointer must not be comptime-known.
var t = S.f;
var frame_ptr = @asyncCall(&buffer, {}, t, .{ F0, undefined, F1 });
}