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bitfields support for array of non-store-aligned packed structs

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This commit is contained in:
Andrew Kelley
2017-02-22 00:49:10 -05:00
parent cf5108f222
commit d794549985
6 changed files with 146 additions and 57 deletions
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29
src/codegen.cpp
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@@ -1466,6 +1466,27 @@ static LLVMValueRef ir_render_elem_ptr(CodeGen *g, IrExecutable *executable, IrI
array_type->data.array.len, false);
add_bounds_check(g, subscript_value, LLVMIntEQ, nullptr, LLVMIntULT, end);
}
if (array_ptr_type->data.pointer.unaligned_bit_count != 0) {
return array_ptr_ptr;
}
TypeTableEntry *canon_child_type = get_underlying_type(array_type->data.array.child_type);
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), "");
}
LLVMValueRef indices[] = {
LLVMConstNull(g->builtin_types.entry_usize->type_ref),
subscript_value
@@ -1552,11 +1573,19 @@ static LLVMValueRef ir_render_struct_field_ptr(CodeGen *g, IrExecutable *executa
IrInstructionStructFieldPtr *instruction)
{
LLVMValueRef struct_ptr = ir_llvm_value(g, instruction->struct_ptr);
// not necessarily a pointer. could be TypeTableEntryIdStruct
TypeTableEntry *struct_ptr_type = instruction->struct_ptr->value.type;
TypeStructField *field = instruction->field;
if (!type_has_bits(field->type_entry))
return nullptr;
if (struct_ptr_type->id == TypeTableEntryIdPointer &&
struct_ptr_type->data.pointer.unaligned_bit_count != 0)
{
return struct_ptr;
}
assert(field->gen_index != SIZE_MAX);
return LLVMBuildStructGEP(g->builder, struct_ptr, field->gen_index, "");
}