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Make __extern_always_inline usable on clang++ again

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Resolves: #1133508
This commit is contained in:
Siddhesh Poyarekar 2014-09-16 22:45:53 +05:30
parent d61fdfcf3b
commit f02067f353
3 changed files with 126 additions and 40 deletions
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90
glibc-extern-always-inline.patch
View File

@ -1,36 +1,48 @@
From 0998aff9be4f0a25b7a822c4f28e832d367977c6 Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh@redhat.com>
Date: Wed, 13 Aug 2014 23:28:18 +0530
Subject: [PATCH] Revert to defining __extern_inline only for gcc-4.3+
commit 884ddc5081278f488ef8cd49951f41cfdbb480ce
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date: Tue Sep 16 14:08:48 2014 +0530
The check for only __GNUC_STDC_INLINE__ and __GNUC_GNU_INLINE__ may
not be sufficient since those flags were added during initial support
for C99 inlining semantics. There is also a problem with always
defining __extern_inline and __extern_always_inline, since it enables
inline wrapper functions even when GNU inlining semantics are not
guaranteed. This, along with the possibility of such wrappers using
redirection (btowc for example) could result in compiler generating an
infinitely recusrive call to the function.
In fact it was such a recursion that led to this code being written
the way it was; see:
https://bugzilla.redhat.com/show_bug.cgi?id=186410
The initial change was to fix bugs 14530 and 13741, but they can be
resolved by checking if __fortify_function and/or
__extern_always_inline are defined, as it has been done in this patch.
In addition, I have audited uses of __extern_always_inline to make
sure that none of the uses result in compilation errors.
There is however a regression in this patch for llvm, since it reverts
the llvm expectation that __GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__
definition imply proper extern inline semantics.
---
libio/stdio.h | 2 +-
math/bits/math-finite.h | 8 +++++---
misc/sys/cdefs.h | 18 ++++++++----------
3 files changed, 14 insertions(+), 14 deletions(-)
Revert to defining __extern_inline only for gcc-4.3+ (BZ #17266)
The check for only __GNUC_STDC_INLINE__ and __GNUC_GNU_INLINE__ may
not be sufficient since those flags were added during initial support
for C99 inlining semantics. There is also a problem with always
defining __extern_inline and __extern_always_inline, since it enables
inline wrapper functions even when GNU inlining semantics are not
guaranteed. This, along with the possibility of such wrappers using
redirection (btowc for example) could result in compiler generating an
infinitely recusrive call to the function.
In fact it was such a recursion that led to this code being written
the way it was; see:
https://bugzilla.redhat.com/show_bug.cgi?id=186410
The initial change was to fix bugs 14530 and 13741, but they can be
resolved by checking if __fortify_function and/or
__extern_always_inline are defined, as it has been done in this patch.
In addition, I have audited uses of __extern_always_inline to make
sure that none of the uses result in compilation errors.
There is however a regression in this patch for llvm, since it reverts
the llvm expectation that __GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__
definition imply proper extern inline semantics.
2014-09-16 Siddhesh Poyarekar <siddhesh@redhat.com>
Jakub Jelinek <jakub@redhat.com>
[BZ #17266]
* libio/stdio.h: Check definition of __fortify_function
instead of __extern_always_inline to include bits/stdio2.h.
* math/bits/math-finite.h [__USE_XOPEN || __USE_ISOC99]: Also
check if __extern_always_inline is defined.
[__USE_MISC || __USE_XOPEN]: Likewise.
[__USE_ISOC99] Likewise.
* misc/sys/cdefs.h (__fortify_function): Define only if
__extern_always_inline is defined.
[!__cplusplus || __GNUC_PREREQ (4,3)]: Revert to defining
__extern_always_inline and __extern_inline only for g++-4.3
and newer or a compatible gcc.
diff --git a/libio/stdio.h b/libio/stdio.h
index d8c0bdb..1f4f837 100644
@ -79,7 +91,7 @@ index aa755de..0656645 100644
extern double __gamma_r_finite (double, int *);
__extern_always_inline double __NTH (tgamma (double __d))
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 04db956..d8ee73c 100644
index 04db956..01e81ba 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -131,7 +131,6 @@
@ -90,7 +102,7 @@ index 04db956..d8ee73c 100644
#if __GNUC_PREREQ (4,3)
# define __warndecl(name, msg) \
@@ -318,12 +317,10 @@
@@ -318,12 +317,13 @@
# define __attribute_artificial__ /* Ignore */
#endif
@ -101,13 +113,16 @@ index 04db956..d8ee73c 100644
- defined, this version of GCC only supports GNU inline semantics. */
-# if defined __GNUC_STDC_INLINE__ || defined __GNUC_GNU_INLINE__
+/* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
+ inline semantics, unless -fgnu89-inline is used. */
+ inline semantics, unless -fgnu89-inline is used. Using __GNUC_STDC_INLINE__
+ or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
+ older than 4.3 may define these macros and still not guarantee GNU inlining
+ semantics. */
+#if !defined __cplusplus || __GNUC_PREREQ (4,3)
+# if defined __GNUC_STDC_INLINE__ || defined __cplusplus
# define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
# define __extern_always_inline \
extern __always_inline __attribute__ ((__gnu_inline__))
@@ -331,9 +328,10 @@
@@ -331,9 +331,10 @@
# define __extern_inline extern __inline
# define __extern_always_inline extern __always_inline
# endif
@ -121,6 +136,3 @@ index 04db956..d8ee73c 100644
#endif
/* GCC 4.3 and above allow passing all anonymous arguments of an
--
1.9.3

69
glibc-rh1133508.patch Normal file
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@ -0,0 +1,69 @@
commit 602f80ec8b966cfad3b61914cbe14ee606cedf6e
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date: Tue Sep 16 22:16:01 2014 +0530
Make __extern_always_inline usable on clang++ again
The fix for BZ #17266 (884ddc5081278f488ef8cd49951f41cfdbb480ce)
removed changes that had gone into cdefs.h to make
__extern_always_inline usable with clang++. This patch adds back
support for clang to detect if GNU inlining semantics are available,
this time without breaking the gcc use case. The check put here is
based on the earlier patch and assertion[1] that checking if
__GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__ is defined is sufficient
to determine that clang++ suports GNU inlining semantics.
Tested with a simple program that builds with __extern_always_inline
with the patch and fails compilation without it.
#include <stdio.h>
#include <sys/cdefs.h>
extern void foo_alias (void) __asm ("foo");
__extern_always_inline void
foo (void)
{
puts ("hi oh world!");
return foo_alias ();
}
void
foo_alias (void)
{
puts ("hell oh world");
}
int
main ()
{
foo ();
}
[1] https://sourceware.org/ml/libc-alpha/2012-12/msg00306.html
[BZ #17266]
* misc/sys/cdefs.h: Define __extern_always_inline for clang
4.2 and newer.
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 01e81ba..711ac1d 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -321,8 +321,14 @@
inline semantics, unless -fgnu89-inline is used. Using __GNUC_STDC_INLINE__
or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
older than 4.3 may define these macros and still not guarantee GNU inlining
- semantics. */
-#if !defined __cplusplus || __GNUC_PREREQ (4,3)
+ semantics.
+
+ clang++ identifies itself as gcc-4.2, but has support for GNU inlining
+ semantics, that can be checked fot by using the __GNUC_STDC_INLINE_ and
+ __GNUC_GNU_INLINE__ macro definitions. */
+#if (!defined __cplusplus || __GNUC_PREREQ (4,3) \
+ || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \
+ || defined __GNUC_GNU_INLINE__)))
# if defined __GNUC_STDC_INLINE__ || defined __cplusplus
# define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
# define __extern_always_inline \

7
glibc.spec
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@ -1,6 +1,6 @@
%define glibcsrcdir glibc-2.20
%define glibcversion 2.20
%define glibcrelease 1%{?dist}
%define glibcrelease 2%{?dist}
# Pre-release tarballs are pulled in from git using a command that is
# effectively:
#
@ -194,6 +194,7 @@ Patch0050: %{name}-rh1124987.patch
# Patches from upstream
#
##############################################################################
Patch1001: %{name}-rh1133508.patch
##############################################################################
#
@ -560,6 +561,7 @@ package or when debugging this package.
%patch2034 -p1
%patch2035 -p1
%patch0050 -p1
%patch1001 -p1
##############################################################################
# %%prep - Additional prep required...
@ -1667,6 +1669,9 @@ rm -f *.filelist*
%endif
%changelog
* Tue Sep 16 2014 Siddhesh Poyarekar <siddhesh@redhat.com> - 2.20-2
- Make __extern_always_inline usable on clang++ again (#1133508).
* Mon Sep 8 2014 Siddhesh Poyarekar <siddhesh@redhat.com> - 2.20-1
- Rebase to upstream release 2.20.