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Update discriminant value also for zero-sized unions

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Fixes #3681
This commit is contained in:
LemonBoy 2019-11-14 10:20:57 +01:00 committed by Andrew Kelley
parent d89f39d719
commit a11da37734
2 changed files with 39 additions and 13 deletions
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33
src/codegen.cpp
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@ -4351,17 +4351,32 @@ static LLVMValueRef ir_render_union_field_ptr(CodeGen *g, IrExecutable *executab
TypeUnionField *field = instruction->field;
if (!type_has_bits(field->type_entry)) {
if (union_type->data.unionation.gen_tag_index == SIZE_MAX) {
ZigType *tag_type = union_type->data.unionation.tag_type;
if (!instruction->initializing || !type_has_bits(tag_type))
return nullptr;
// The field has no bits but we still have to change the discriminant
// value here
LLVMValueRef union_ptr = ir_llvm_value(g, instruction->union_ptr);
LLVMTypeRef tag_type_ref = get_llvm_type(g, tag_type);
LLVMValueRef tag_field_ptr = nullptr;
if (union_type->data.unionation.gen_field_count == 0) {
assert(union_type->data.unionation.gen_tag_index == SIZE_MAX);
// The whole union is collapsed into the discriminant
tag_field_ptr = LLVMBuildBitCast(g->builder, union_ptr,
LLVMPointerType(tag_type_ref, 0), "");
} else {
assert(union_type->data.unionation.gen_tag_index != SIZE_MAX);
tag_field_ptr = LLVMBuildStructGEP(g->builder, union_ptr,
union_type->data.unionation.gen_tag_index, "");
}
if (instruction->initializing) {
LLVMValueRef union_ptr = ir_llvm_value(g, instruction->union_ptr);
LLVMValueRef tag_field_ptr = LLVMBuildStructGEP(g->builder, union_ptr,
union_type->data.unionation.gen_tag_index, "");
LLVMValueRef tag_value = bigint_to_llvm_const(get_llvm_type(g, union_type->data.unionation.tag_type),
&field->enum_field->value);
gen_store_untyped(g, tag_value, tag_field_ptr, 0, false);
}
LLVMValueRef tag_value = bigint_to_llvm_const(tag_type_ref,
&field->enum_field->value);
assert(tag_field_ptr != nullptr);
gen_store_untyped(g, tag_value, tag_field_ptr, 0, false);
return nullptr;
}

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

@ -110,7 +110,7 @@ fn doTest() void {
}
fn bar(value: Payload) i32 {
expect(@as(Letter,value) == Letter.A);
expect(@as(Letter, value) == Letter.A);
return switch (value) {
Payload.A => |x| return x - 1244,
Payload.B => |x| if (x == 12.34) @as(i32, 20) else 21,
@ -208,7 +208,7 @@ test "cast union to tag type of union" {
}
fn testCastUnionToTagType(x: TheUnion) void {
expect(@as(TheTag,x) == TheTag.B);
expect(@as(TheTag, x) == TheTag.B);
}
test "cast tag type of union to union" {
@ -558,16 +558,27 @@ test "anonymous union literal syntax" {
};
fn doTheTest() void {
var i: Number = .{.int = 42};
var i: Number = .{ .int = 42 };
var f = makeNumber();
expect(i.int == 42);
expect(f.float == 12.34);
}
fn makeNumber() Number {
return .{.float = 12.34};
return .{ .float = 12.34 };
}
};
S.doTheTest();
comptime S.doTheTest();
}
test "update the tag value for zero-sized unions" {
const S = union(enum) {
U0: void,
U1: void,
};
var x = S{ .U0 = {} };
expect(x == .U0);
x = S{ .U1 = {} };
expect(x == .U1);
}