libc++ recursive `setjmp()` macro causes `-Wdisabled-macro-expansion warning`

[seanm]

Bugzilla Link	26717
Version	trunk
OS	MacOS X

Extended Description

Consider this reduced/trivial C++ snippet:

#include <setjmp.h>

int main()
{
  setjmp(0);
  return 0;
}

compiling with clang trunk gives:

/Users/sean/test.cxx:5:3: warning: disabled expansion of recursive macro [-Wdisabled-macro-expansion]
  setjmp(0);
  ^
/Users/sean/llvm/llvm-rel-install/bin/../include/c++/v1/setjmp.h:40:21: note: expanded from macro 'setjmp'
#define setjmp(env) setjmp(env)
                    ^

(If I use a .c file, I don't get the warning.)

As that's an llvm header (and has #pragma GCC system_header), I would hope not to get this warning.

[seanm]

FYI: still reproduces with today's clang:
clang version 6.0.0 (trunk 314864) (llvm/trunk 314863)

[seanm]

Just a note to say it still occurs with trunk 347180.

Also, it doesn't matter if I include <setjmp.h> or <csetjmp>.

[llvmbot]

@llvm/issue-subscribers-c-1

Author: Sean McBride (seanm)

Details

| | | | --- | --- | | Bugzilla Link | [26717](https://llvm.org/bz26717) | | Version | trunk | | OS | MacOS X |

Extended Description

Consider this reduced/trivial C++ snippet:

#include <setjmp.h>

int main()
{
  setjmp(0);
  return 0;
}

compiling with clang trunk gives:

/Users/sean/test.cxx:5:3: warning: disabled expansion of recursive macro [-Wdisabled-macro-expansion]
  setjmp(0);
  ^
/Users/sean/llvm/llvm-rel-install/bin/../include/c++/v1/setjmp.h:40:21: note: expanded from macro 'setjmp'
#define setjmp(env) setjmp(env)
                    ^

(If I use a .c file, I don't get the warning.)

As that's an llvm header (and has #pragma GCC system_header), I would hope not to get this warning.

[philnik777]

We don't have a setjmp.h anymore, so this should be fixed. I can't reproduce it either though. (OTOH it might be a macos-specific problem, so I wouldn't be able reproduce it either)

[seanm]

I just tried to repro with Xcode 16.2's clang, no longer repro. I guess it got fixed.