[PATCH] D122248: [clang][CodeGen]Fix clang crash and add bitfield support in __builtin_dump_struct

[Wang Yihan via Phabricator via cfe-commits]

yihanaa added a comment.

In D122248#3403315 <https://reviews.llvm.org/D122248#3403315>, @aaron.ballman wrote:

> In D122248#3403143 <https://reviews.llvm.org/D122248#3403143>, @yihanaa wrote:
>
>> 1. Support zero-width bitfield, named bitfield and unnamed bitfield.
>> 2. Add a release notes.
>>
>> The builtin function __builtin_dump_struct behaves for zero-width bitfield and unnamed bitfield as follows
>>
>>   int printf(const char *fmt, ...);
>>   
>>   void foo(void) {
>>     struct Bar {
>>       unsigned c : 1;
>>       unsigned : 3;
>>       unsigned : 0;
>>       unsigned b;
>>     };
>>   
>>     struct Bar a = {
>>       .c = 1,
>>       .b = 2022,
>>     };
>>   
>>     __builtin_dump_struct(&a, &printf);
>>   }
>>   
>>   int main() {
>>     foo();
>>     return 0;
>>   }
>>
>> Output:
>>
>>   struct Bar {
>>   unsigned int c : 1
>>   unsigned int  : 0
>>   unsigned int b : 2022
>>   }
>
> Thank you for the release note and additional test coverage. I'm wondering why we handle the zero-width bit-field differently from the anonymous one (e.g., why do we not have `unsigned int : 3` before the `unsigned int : 0`? It seems a bit odd to drop that from the output.

Thanks, I don't know what the value of this zero-width bitfield should output, can it be a empty value as same as unnamed-bitfield’ she field name?


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https://reviews.llvm.org/D122248