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commit 602f80ec8b966cfad3b61914cbe14ee606cedf6e
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Author: Siddhesh Poyarekar <siddhesh@redhat.com>
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Date:   Tue Sep 16 22:16:01 2014 +0530
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    Make __extern_always_inline usable on clang++ again
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    The fix for BZ #17266 (884ddc5081278f488ef8cd49951f41cfdbb480ce)
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    removed changes that had gone into cdefs.h to make
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    __extern_always_inline usable with clang++.  This patch adds back
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    support for clang to detect if GNU inlining semantics are available,
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    this time without breaking the gcc use case.  The check put here is
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    based on the earlier patch and assertion[1] that checking if
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    __GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__ is defined is sufficient
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    to determine that clang++ suports GNU inlining semantics.
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    Tested with a simple program that builds with __extern_always_inline
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    with the patch and fails compilation without it.
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     #include <stdio.h>
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     #include <sys/cdefs.h>
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    extern void foo_alias (void) __asm ("foo");
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    __extern_always_inline void
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    foo (void)
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    {
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      puts ("hi oh world!");
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      return foo_alias ();
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    }
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    void
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    foo_alias (void)
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    {
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      puts ("hell oh world");
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    }
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    int
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    main ()
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    {
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      foo ();
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    }
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    [1] https://sourceware.org/ml/libc-alpha/2012-12/msg00306.html
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    	[BZ #17266]
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    	* misc/sys/cdefs.h: Define __extern_always_inline for clang
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    	4.2 and newer.
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commit 884ddc5081278f488ef8cd49951f41cfdbb480ce
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Author: Siddhesh Poyarekar <siddhesh@redhat.com>
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Date:   Tue Sep 16 14:08:48 2014 +0530
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    Revert to defining __extern_inline only for gcc-4.3+ (BZ #17266)
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    The check for only __GNUC_STDC_INLINE__ and __GNUC_GNU_INLINE__ may
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    not be sufficient since those flags were added during initial support
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    for C99 inlining semantics.  There is also a problem with always
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    defining __extern_inline and __extern_always_inline, since it enables
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    inline wrapper functions even when GNU inlining semantics are not
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    guaranteed.  This, along with the possibility of such wrappers using
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    redirection (btowc for example) could result in compiler generating an
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    infinitely recusrive call to the function.
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    In fact it was such a recursion that led to this code being written
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    the way it was; see:
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    https://bugzilla.redhat.com/show_bug.cgi?id=186410
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    The initial change was to fix bugs 14530 and 13741, but they can be
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    resolved by checking if __fortify_function and/or
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    __extern_always_inline are defined, as it has been done in this patch.
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    In addition, I have audited uses of __extern_always_inline to make
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    sure that none of the uses result in compilation errors.
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    There is however a regression in this patch for llvm, since it reverts
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    the llvm expectation that __GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__
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    definition imply proper extern inline semantics.
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    2014-09-16  Siddhesh Poyarekar  <siddhesh@redhat.com>
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    	    Jakub Jelinek  <jakub@redhat.com>
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    	[BZ #17266]
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    	* libio/stdio.h: Check definition of __fortify_function
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    	instead of __extern_always_inline to include bits/stdio2.h.
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    	* math/bits/math-finite.h [__USE_XOPEN || __USE_ISOC99]: Also
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    	check if __extern_always_inline is defined.
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    	[__USE_MISC || __USE_XOPEN]: Likewise.
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    	[__USE_ISOC99] Likewise.
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    	* misc/sys/cdefs.h (__fortify_function): Define only if
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    	__extern_always_inline is defined.
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    	[!__cplusplus || __GNUC_PREREQ (4,3)]: Revert to defining
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    	__extern_always_inline and __extern_inline only for g++-4.3
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    	and newer or a compatible gcc.
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diff --git glibc-2.17-c758a686/libio/stdio.h glibc-2.17-c758a686/libio/stdio.h
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index d8c0bdb..1f4f837 100644
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--- glibc-2.17-c758a686/libio/stdio.h
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+++ glibc-2.17-c758a686/libio/stdio.h
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@@ -932,7 +932,7 @@ extern void funlockfile (FILE *__stream) __THROW;
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 #ifdef __USE_EXTERN_INLINES
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 # include <bits/stdio.h>
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 #endif
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-#if __USE_FORTIFY_LEVEL > 0 && defined __extern_always_inline
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+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
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 # include <bits/stdio2.h>
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 #endif
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 #ifdef __LDBL_COMPAT
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diff --git glibc-2.17-c758a686/math/bits/math-finite.h glibc-2.17-c758a686/math/bits/math-finite.h
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index aa755de..0656645 100644
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--- glibc-2.17-c758a686/math/bits/math-finite.h
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+++ glibc-2.17-c758a686/math/bits/math-finite.h
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@@ -251,7 +251,8 @@ extern long double __REDIRECT_NTH (lgammal_r, (long double, int *),
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 # endif
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 #endif
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-#if defined __USE_MISC || defined __USE_XOPEN || defined __USE_ISOC99
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+#if ((defined __USE_MISC || defined __USE_XOPEN || defined __USE_ISOC99) \
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+     && defined __extern_always_inline)
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 /* lgamma.  */
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 __extern_always_inline double __NTH (lgamma (double __d))
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 {
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@@ -284,7 +285,8 @@ __extern_always_inline long double __NTH (lgammal (long double __d))
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 # endif
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 #endif
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-#if defined __USE_MISC || defined __USE_XOPEN
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+#if ((defined __USE_MISC || defined __USE_XOPEN) \
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+     && defined __extern_always_inline)
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 /* gamma.  */
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 __extern_always_inline double __NTH (gamma (double __d))
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 {
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@@ -422,7 +424,7 @@ extern long double __REDIRECT_NTH (sqrtl, (long double), __sqrtl_finite);
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 # endif
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 #endif
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-#ifdef __USE_ISOC99
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+#if defined __USE_ISOC99 && defined __extern_always_inline
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 /* tgamma.  */
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 extern double __gamma_r_finite (double, int *);
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 __extern_always_inline double __NTH (tgamma (double __d))
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diff --git glibc-2.17-c758a686/misc/sys/cdefs.h glibc-2.17-c758a686/misc/sys/cdefs.h
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index 04db956..01e81ba 100644
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--- glibc-2.17-c758a686/misc/sys/cdefs.h
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+++ glibc-2.17-c758a686/misc/sys/cdefs.h
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@@ -131,7 +131,6 @@
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 /* Fortify support.  */
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 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
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 #define __bos0(ptr) __builtin_object_size (ptr, 0)
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-#define __fortify_function __extern_always_inline __attribute_artificial__
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 #if __GNUC_PREREQ (4,3)
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 # define __warndecl(name, msg) \
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@@ -319,8 +318,17 @@
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 #endif
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 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
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-   inline semantics, unless -fgnu89-inline is used.  */
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-#if (!defined __cplusplus || __GNUC_PREREQ (4,3)) && defined __GNUC__
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+   inline semantics, unless -fgnu89-inline is used.  Using __GNUC_STDC_INLINE__
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+   or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
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+   older than 4.3 may define these macros and still not guarantee GNU inlining
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+   semantics.
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+
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+   clang++ identifies itself as gcc-4.2, but has support for GNU inlining
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+   semantics, that can be checked fot by using the __GNUC_STDC_INLINE_ and
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+   __GNUC_GNU_INLINE__ macro definitions.  */
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+#if (!defined __cplusplus || __GNUC_PREREQ (4,3) \
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+     || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \
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+			       || defined __GNUC_GNU_INLINE__)))
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 # if defined __GNUC_STDC_INLINE__ || defined __cplusplus
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 #  define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
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 #  define __extern_always_inline \
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@@ -329,13 +337,10 @@
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 #  define __extern_inline extern __inline
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 #  define __extern_always_inline extern __always_inline
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 # endif
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-#elif defined __GNUC__ /* C++ and GCC <4.3.  */
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-# define __extern_inline extern __inline
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-# define __extern_always_inline \
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-  extern __always_inline
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-#else /* Not GCC.  */
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-# define __extern_inline  /* Ignore */
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-# define __extern_always_inline /* Ignore */
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+#endif
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+
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+#ifdef __extern_always_inline
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+# define __fortify_function __extern_always_inline __attribute_artificial__
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 #endif
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 /* GCC 4.3 and above allow passing all anonymous arguments of an