RFR: 8345757: [ASAN] clang17 report 'dprintf' macro redefined [v4]

[Kim Barrett]

On Sun, 22 Dec 2024 02:38:31 GMT, SendaoYan <syan at openjdk.org> wrote:

>> Hi all,
>> File src/java.smartcardio/share/native/libj2pcsc/pcsc.c and src/jdk.crypto.cryptoki/share/native/libj2pkcs11/j2secmod.h generate compile warning `'dprintf' macro redefined` by clang17/llvm17 with fastdebug configure. This PR rename dprintf to debug_printf and make it variadic, to avoid deplication macro definition to linux header `/usr/include/bits/stdio2.h`, risk is low.
>> 
>> Additional testing:
>> 
>> - [x] build with fastdebug and release configure by gcc14 on linux-x64
>> - [x] jtreg tests(include tier1/2/3 etc.) on linux-x64 with release build
>> - [x] jtreg tests(include tier1/2/3 etc.) on linux-x64 with fastdebug build
>> - [x] jtreg tests(include tier1/2/3 etc.) on linux-aarch64 with release build
>> - [x] jtreg tests(include tier1/2/3 etc.) on linux-aarch64 with fastdebug build
>
> SendaoYan has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into jbs8345757
>  - rename dprintf to debug_printf and make it variadic
>  - add comments // GNU, POSIX.1-2008
>  - Merge branch 'openjdk:master' into jbs8345757
>  - 8345757: [ASAN] clang17 report dprintf macro redefined

Looks good to me, but you should get reviews from folks directly involved in
the relevant areas.

src/java.smartcardio/share/native/libj2pcsc/pcsc.c line 43:

> 41: 
> 42: #ifdef J2PCSC_DEBUG
> 43: #define debug_printf(format, ...) printf(format, ##__VA_ARGS__)

`##__VA_ARGS__` is a gcc extension that is also supported by clang and MSVC++
(for MSVC++, maybe only with recent versions or necessary flags that we're
using?). The standard way to accomplish this sort of thing is `__VA_OPT__`,
but that's a C++20/C23 feature, so not available to us. It seems we're already
using that extension in over 50 places in the JDK (nearly a dozon in HotSpot).
So okay.

Though I think `debug_printf(...) printf(__VA_ARGS__)` instead would work in
this case.  It's not quite as nicely self-documenting though.

-------------

Marked as reviewed by kbarrett (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/22630#pullrequestreview-2521159879
PR Review Comment: https://git.openjdk.org/jdk/pull/22630#discussion_r1896134688