[pushed] Don't use a custom wrapper macro around __has_include (bug 25189).
Commit Message
Sourceware to Gerrit sync has submitted this change.
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/glibc/+/697
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Don't use a custom wrapper macro around __has_include (bug 25189).
This causes issues when using clang with -frewrite-includes to e.g.,
submit the translation unit to a distributed compiler.
In my case, I was building Firefox using sccache.
See [1] for a reduced test-case since I initially thought this was a
clang bug, and [2] for more context.
Apparently doing this is invalid C++ per [cpp.cond], which mentions [3]:
> The #ifdef and #ifndef directives, and the defined conditional
> inclusion operator, shall treat __has_include and __has_cpp_attribute
> as if they were the names of defined macros. The identifiers
> __has_include and __has_cpp_attribute shall not appear in any context
> not mentioned in this subclause.
[1]: https://bugs.llvm.org/show_bug.cgi?id=43982
[2]: https://bugs.llvm.org/show_bug.cgi?id=37990
[3]: http://eel.is/c++draft/cpp.cond#7.sentence-2
Change-Id: Id4b8ee19176a9e4624b533087ba870c418f27e60
---
M misc/sys/cdefs.h
M sysdeps/unix/sysv/linux/bits/statx.h
2 files changed, 7 insertions(+), 13 deletions(-)
Approvals:
Florian Weimer: Looks good to me, approved
@@ -412,14 +412,6 @@
# define __glibc_has_attribute(attr) 0
#endif
-#ifdef __has_include
-/* Do not use a function-like macro, so that __has_include can inhibit
- macro expansion. */
-# define __glibc_has_include __has_include
-#else
-# define __glibc_has_include(header) 0
-#endif
-
#if (!defined _Noreturn \
&& (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
&& !__GNUC_PREREQ (4,7))
@@ -26,11 +26,13 @@
/* Use "" to work around incorrect macro expansion of the
__has_include argument (GCC PR 80005). */
-#if __glibc_has_include ("linux/stat.h")
-# include "linux/stat.h"
-# ifdef STATX_TYPE
-# define __statx_timestamp_defined 1
-# define __statx_defined 1
+#ifdef __has_include
+# if __has_include ("linux/stat.h")
+# include "linux/stat.h"
+# ifdef STATX_TYPE
+# define __statx_timestamp_defined 1
+# define __statx_defined 1
+# endif
# endif
#endif