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fix regression with bit fields that align properly

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This commit is contained in:
Andrew Kelley 2017-02-22 00:54:11 -05:00
parent d794549985
commit 786677f80c
2 changed files with 39 additions and 12 deletions
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25
src/codegen.cpp
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@ -1473,19 +1473,20 @@ static LLVMValueRef ir_render_elem_ptr(CodeGen *g, IrExecutable *executable, IrI
if (canon_child_type->id == TypeTableEntryIdStruct &&
canon_child_type->data.structure.layout == ContainerLayoutPacked)
{
LLVMTypeRef ptr_u8_type_ref = LLVMPointerType(LLVMInt8Type(), 0);
LLVMValueRef u8_array_ptr = LLVMBuildBitCast(g->builder, array_ptr, ptr_u8_type_ref, "");
size_t unaligned_bit_count = instruction->base.value.type->data.pointer.unaligned_bit_count;
assert(unaligned_bit_count != 0);
assert(unaligned_bit_count % 8 == 0);
LLVMValueRef elem_size_bytes = LLVMConstInt(g->builtin_types.entry_usize->type_ref,
unaligned_bit_count / 8, false);
LLVMValueRef byte_offset = LLVMBuildNUWMul(g->builder, subscript_value, elem_size_bytes, "");
LLVMValueRef indices[] = {
byte_offset
};
LLVMValueRef elem_byte_ptr = LLVMBuildInBoundsGEP(g->builder, u8_array_ptr, indices, 1, "");
return LLVMBuildBitCast(g->builder, elem_byte_ptr, LLVMPointerType(canon_child_type->type_ref, 0), "");
if (unaligned_bit_count != 0) {
LLVMTypeRef ptr_u8_type_ref = LLVMPointerType(LLVMInt8Type(), 0);
LLVMValueRef u8_array_ptr = LLVMBuildBitCast(g->builder, array_ptr, ptr_u8_type_ref, "");
assert(unaligned_bit_count % 8 == 0);
LLVMValueRef elem_size_bytes = LLVMConstInt(g->builtin_types.entry_usize->type_ref,
unaligned_bit_count / 8, false);
LLVMValueRef byte_offset = LLVMBuildNUWMul(g->builder, subscript_value, elem_size_bytes, "");
LLVMValueRef indices[] = {
byte_offset
};
LLVMValueRef elem_byte_ptr = LLVMBuildInBoundsGEP(g->builder, u8_array_ptr, indices, 1, "");
return LLVMBuildBitCast(g->builder, elem_byte_ptr, LLVMPointerType(canon_child_type->type_ref, 0), "");
}
}
LLVMValueRef indices[] = {
LLVMConstNull(g->builtin_types.entry_usize->type_ref),

26
test/cases/struct.zig
View File

@ -369,3 +369,29 @@ fn packedArray24Bits() {
assert(bytes[bytes.len - 1] == 0xaa);
}
const FooStructAligned = packed struct {
a: u8,
b: u8,
};
const FooArrayOfAligned = packed struct {
a: [2]FooStructAligned,
};
fn alignedArrayOfPackedStruct() {
@setFnTest(this);
comptime {
assert(@sizeOf(FooStructAligned) == 2);
assert(@sizeOf(FooArrayOfAligned) == 2 * 2);
}
var bytes = []u8{0xbb} ** @sizeOf(FooArrayOfAligned);
const ptr = &([]FooArrayOfAligned)(bytes[0...bytes.len])[0];
assert(ptr.a[0].a == 0xbb);
assert(ptr.a[0].b == 0xbb);
assert(ptr.a[1].a == 0xbb);
assert(ptr.a[1].b == 0xbb);
}