Re: [PATCH] fix ___SYNC () build error when PROFILE_ALL_BRANCHES is enabled

[Randy Dunlap]

Hi--

> 
> Maybe the readability of this modification is not very good. Any
> comments and suggestions are welcome. Thanks.

Some of the patch description could use some cleaning up,
then I have a question.


On 4/26/23 06:02, genjian zhang wrote:
> On Wed, Apr 26, 2023 at 8:51 PM Genjian <zhanggenjian123@xxxxxxxxx> wrote:
>>
>> From: Genjian Zhang <zhanggenjian@xxxxxxxxxx>
>>
>> compiler error (mips-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110):
>>
>> {standard input}: Assembler messages:
>> {standard input}:171: Error: found '(', expected: ')'
>> {standard input}:171: Error: found '(', expected: ')'
>> {standard input}:171: Error: non-constant expression in ".if" statement
>> {standard input}:171: Error: junk at end of line, first unrecognized
>> character is `('
>>
>> Preprocessor expand ___SYNC () macros.However,'if' will be wrongly

                expands ___SYNC() macros. However, 'if' will be wrongly

>> replaced by C code when PROFILE_ALL_BRANCHES is enabled and ___SYNC
>> is used in inline assembly.This leads to syntax errors in the code.

                     assembly. This

>> Compilers report a lot of errors like the above.
>> Move '.if' into quoted strings to fix it.
>>
>> Reported-by: k2ci <kernel-bot@xxxxxxxxxx>
>> Signed-off-by: Genjian Zhang <zhanggenjian@xxxxxxxxxx>
>> ---
>>  arch/mips/include/asm/sync.h | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/mips/include/asm/sync.h b/arch/mips/include/asm/sync.h
>> index aabd097933fe..d9f5a87424e7 100644
>> --- a/arch/mips/include/asm/sync.h
>> +++ b/arch/mips/include/asm/sync.h
>> @@ -175,7 +175,7 @@
>>   */
>>  #ifdef CONFIG_CPU_HAS_SYNC
>>  # define ____SYNC(_type, _reason, _else)                       \
>> -       .if     (( _type ) != -1) && ( _reason );               \
>> +       ((_type) != -1) && (_reason);                           \
>>         .set    push;                                           \
>>         .set    MIPS_ISA_LEVEL_RAW;                             \
>>         .rept   __SYNC_rpt(_type);                              \
>> @@ -192,13 +192,15 @@
>>  /*
>>   * Preprocessor magic to expand macros used as arguments before we insert them
>>   * into assembly code.
>> + * In addition,‘if’ can not be substituted when CONFIG_PROFILE_ALL_BRANCHES is

     * In addition, 'if' cannot be

>> + * enabled.
>>   */
>>  #ifdef __ASSEMBLY__
>>  # define ___SYNC(type, reason, else)                           \
>> -       ____SYNC(type, reason, else)
>> +       .if     ____SYNC(type, reason, else)
>>  #else
>>  # define ___SYNC(type, reason, else)                           \
>> -       __stringify(____SYNC(type, reason, else))
>> +       ".if"   __stringify(____SYNC(type, reason, else))
>>  #endif
>>
>>  #define __SYNC(type, reason)                                   \
>> --
>> 2.25.1


Is this problem that you are fixing being aggravated (caused) by
the #define of if() in include/linux/compiler.h when CONFIG_PROFILE_ALL_BRANCHES
is set?  I suspect that it is.
It wouldn't hurt to mention that (if I am correct).

Thanks.
-- 
~Randy