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unions have a secret field for the type

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See #144
This commit is contained in:
Andrew Kelley
2017-11-15 22:52:47 -05:00
parent f276fd0f37
commit 018cbff438
4 changed files with 195 additions and 31 deletions
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61
src/codegen.cpp
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@@ -2408,9 +2408,15 @@ static LLVMValueRef ir_render_union_field_ptr(CodeGen *g, IrExecutable *executab
LLVMValueRef union_ptr = ir_llvm_value(g, instruction->union_ptr);
LLVMTypeRef field_type_ref = LLVMPointerType(field->type_entry->type_ref, 0);
LLVMValueRef union_field_ptr = LLVMBuildStructGEP(g->builder, union_ptr, 0, "");
LLVMValueRef bitcasted_union_field_ptr = LLVMBuildBitCast(g->builder, union_field_ptr, field_type_ref, "");
if (union_type->data.unionation.gen_tag_index == SIZE_MAX) {
LLVMValueRef union_field_ptr = LLVMBuildStructGEP(g->builder, union_ptr, 0, "");
LLVMValueRef bitcasted_union_field_ptr = LLVMBuildBitCast(g->builder, union_field_ptr, field_type_ref, "");
return bitcasted_union_field_ptr;
}
LLVMValueRef union_field_ptr = LLVMBuildStructGEP(g->builder, union_ptr, union_type->data.unionation.gen_union_index, "");
LLVMValueRef bitcasted_union_field_ptr = LLVMBuildBitCast(g->builder, union_field_ptr, field_type_ref, "");
return bitcasted_union_field_ptr;
}
@@ -3955,7 +3961,7 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val) {
}
case TypeTableEntryIdUnion:
{
LLVMTypeRef union_type_ref = type_entry->type_ref;
LLVMTypeRef union_type_ref = type_entry->data.unionation.union_type_ref;
ConstExprValue *payload_value = const_val->data.x_union.value;
assert(payload_value != nullptr);
@@ -3964,29 +3970,48 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val) {
}
uint64_t field_type_bytes = LLVMStoreSizeOfType(g->target_data_ref, payload_value->type->type_ref);
uint64_t pad_bytes = type_entry->data.unionation.size_bytes - field_type_bytes;
uint64_t pad_bytes = type_entry->data.unionation.union_size_bytes - field_type_bytes;
LLVMValueRef correctly_typed_value = gen_const_val(g, payload_value);
bool make_unnamed_struct = is_llvm_value_unnamed_type(payload_value->type, correctly_typed_value) ||
payload_value->type != type_entry->data.unionation.most_aligned_union_member;
unsigned field_count;
LLVMValueRef fields[2];
fields[0] = correctly_typed_value;
if (pad_bytes == 0) {
field_count = 1;
} else {
LLVMValueRef union_value_ref;
{
unsigned field_count;
LLVMValueRef fields[2];
fields[0] = correctly_typed_value;
fields[1] = LLVMGetUndef(LLVMArrayType(LLVMInt8Type(), (unsigned)pad_bytes));
field_count = 2;
if (pad_bytes == 0) {
field_count = 1;
} else {
fields[0] = correctly_typed_value;
fields[1] = LLVMGetUndef(LLVMArrayType(LLVMInt8Type(), (unsigned)pad_bytes));
field_count = 2;
}
if (make_unnamed_struct || type_entry->data.unionation.gen_tag_index != SIZE_MAX) {
union_value_ref = LLVMConstStruct(fields, field_count, false);
} else {
union_value_ref = LLVMConstNamedStruct(union_type_ref, fields, field_count);
}
}
if (make_unnamed_struct) {
return LLVMConstStruct(fields, field_count, false);
} else {
return LLVMConstNamedStruct(type_entry->type_ref, fields, field_count);
if (type_entry->data.unionation.gen_tag_index == SIZE_MAX) {
return union_value_ref;
}
size_t distinct_type_index = type_entry->data.unionation.distinct_types.get(const_val->data.x_union.value->type);
LLVMValueRef tag_value = LLVMConstInt(type_entry->data.unionation.tag_type->type_ref, distinct_type_index, false);
LLVMValueRef fields[2];
fields[type_entry->data.unionation.gen_union_index] = union_value_ref;
fields[type_entry->data.unionation.gen_tag_index] = tag_value;
if (make_unnamed_struct) {
return LLVMConstStruct(fields, 2, false);
} else {
return LLVMConstNamedStruct(type_entry->type_ref, fields, 2);
}
}
case TypeTableEntryIdEnum:
{