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fix codegen for union init with runtime value

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see #144
This commit is contained in:
Andrew Kelley 2017-11-16 22:06:08 -05:00
parent e26ccd5166
commit 5d2ba056c8
2 changed files with 40 additions and 5 deletions
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27
src/codegen.cpp
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@ -3414,17 +3414,34 @@ static LLVMValueRef ir_render_struct_init(CodeGen *g, IrExecutable *executable,
static LLVMValueRef ir_render_union_init(CodeGen *g, IrExecutable *executable, IrInstructionUnionInit *instruction) {
TypeUnionField *type_union_field = instruction->field;
assert(type_has_bits(type_union_field->type_entry));
LLVMValueRef field_ptr = LLVMBuildStructGEP(g->builder, instruction->tmp_ptr, (unsigned)0, "");
LLVMValueRef value = ir_llvm_value(g, instruction->init_value);
if (!type_has_bits(type_union_field->type_entry))
return nullptr;
uint32_t field_align_bytes = get_abi_alignment(g, type_union_field->type_entry);
TypeTableEntry *ptr_type = get_pointer_to_type_extra(g, type_union_field->type_entry,
false, false, field_align_bytes,
0, 0);
LLVMValueRef uncasted_union_ptr;
// Even if safety is off in this block, if the union type has the safety field, we have to populate it
// correctly. Otherwise safety code somewhere other than here could fail.
TypeTableEntry *union_type = instruction->union_type;
if (union_type->data.unionation.gen_tag_index != SIZE_MAX) {
LLVMValueRef tag_field_ptr = LLVMBuildStructGEP(g->builder, instruction->tmp_ptr,
union_type->data.unionation.gen_tag_index, "");
LLVMValueRef tag_value = LLVMConstInt(union_type->data.unionation.tag_type->type_ref,
type_union_field->value, false);
gen_store_untyped(g, tag_value, tag_field_ptr, 0, false);
uncasted_union_ptr = LLVMBuildStructGEP(g->builder, instruction->tmp_ptr,
(unsigned)union_type->data.unionation.gen_union_index, "");
} else {
uncasted_union_ptr = LLVMBuildStructGEP(g->builder, instruction->tmp_ptr, (unsigned)0, "");
}
LLVMValueRef field_ptr = LLVMBuildBitCast(g->builder, uncasted_union_ptr, ptr_type->type_ref, "");
LLVMValueRef value = ir_llvm_value(g, instruction->init_value);
gen_assign_raw(g, field_ptr, ptr_type, value);
return instruction->tmp_ptr;

18
test/cases/union.zig
View File

@ -45,6 +45,23 @@ test "basic unions" {
assert(foo.float == 12.34);
}
test "init union with runtime value" {
var foo: Foo = undefined;
setFloat(&foo, 12.34);
assert(foo.float == 12.34);
setInt(&foo, 42);
assert(foo.int == 42);
}
fn setFloat(foo: &Foo, x: f64) {
*foo = Foo { .float = x };
}
fn setInt(foo: &Foo, x: i32) {
*foo = Foo { .int = x };
}
const FooExtern = extern union {
float: f64,
@ -57,3 +74,4 @@ test "basic extern unions" {
foo.float = 12.34;
assert(foo.float == 12.34);
}