Commit fea35ce6 authored by Thomas Petazzoni's avatar Thomas Petazzoni Committed by Peter Korsgaard
Browse files

gcc/4.7: fix C++ exceptions and pthread_exit() 



Following the introduction of the support for the musl C library, the
support of C++ exceptions or features like pthread_exit() got broken
even with other libraries such as glibc. This was reported as bug #7028.

The problem was caused by the gcc patch needed to add support for
musl, which modified the libgcc/unwind-dw2-fde-dip.c logic to decide
whether USE_PT_GNU_EH_FRAME should be enabled or not. It completely
removed the existing logic, replacing it by a single logic based on
the definition of TARGET_DL_ITERATE_PHDR. However, this constant gets
defined by the configure script only for Solaris, or Linux Musl
platforms. For glibc/uClibc, the configure script does not define it,
and therefore USE_PT_GNU_EH_FRAME is not defined, causing issues with
exception handling.

This patch fixes that by restoring all the logic of
libgcc/unwind-dw2-fde-dip.c, and just adding the musl logic as one
more case.

It has been successfully runtime tested using the two code examples
provided in bug #7208, with uClibc, musl and glibc.

Cc: Krzysztof Wrzalik <kwrzalik@gmail.com>
Cc: David Bachelart <david.bachelart@bbright.com>
Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: default avatarPeter Korsgaard <peter@korsgaard.com>
parent 4bb2a05e

package/gcc/4.7.4/900-musl-support.patch

+23 −38
Original line number Diff line number Diff line
@@ -13,6 +13,12 @@ https://bitbucket.org/GregorR/musl-cross/src. Compared to the upstream version: 
   causing build failure. Bug reported upstream at

   https://bitbucket.org/GregorR/musl-gcc-patches/issue/4/musl-gcc-patches-break-the-build-on.



 * change the USE_PT_GNU_EH_FRAME logic to keep the existing gcc logic

   and only add the musl one as an addition, not as a replacement. Not

   doing this breaks C++ exception handling with glibc, because

   USE_PT_GNU_EH_FRAME doesn't get defined due to the configure script

   not testing dl_iterate_phdr() on any system except Solaris.



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

---
@@ -71,7 +77,7 @@ Index: b/gcc/config.gcc 
     *)

       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"

       ;;

@@ -2092,6 +2095,10 @@

@@ -2091,6 +2094,10 @@

 	    powerpc*-*-linux*paired*)

 		tm_file="${tm_file} rs6000/750cl.h" ;;

 	esac
@@ -299,46 +305,25 @@ Index: b/libgcc/unwind-dw2-fde-dip.c 
===================================================================

--- a/libgcc/unwind-dw2-fde-dip.c

+++ b/libgcc/unwind-dw2-fde-dip.c

@@ -47,28 +47,13 @@

 #include "unwind-compat.h"

 #include "gthr.h"

 

-#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \

-    && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \

-	|| (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))

-# define USE_PT_GNU_EH_FRAME

-#endif

-

-#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \

-    && defined(__FreeBSD__) && __FreeBSD__ >= 7

-# define ElfW __ElfN

-# define USE_PT_GNU_EH_FRAME

-#endif

-

-#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \

-    && defined(__OpenBSD__)

-# define ElfW(type) Elf_##type

-# define USE_PT_GNU_EH_FRAME

-#endif

-

-#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \

-    && defined(TARGET_DL_ITERATE_PHDR) \

-    && defined(__sun__) && defined(__svr4__)

+#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) && defined(TARGET_DL_ITERATE_PHDR)

@@ -71,6 +71,13 @@

 # define USE_PT_GNU_EH_FRAME

+# ifdef __OpenBSD__

+#  define ElfW(type) Elf_##typ

+# elif defined(__FreeBSD__) && __FreeBSD__ >= 7

+#  define ElfW __ElfN

+# endif

 #endif

 

+/* For musl libc, TARGET_DL_ITERATE_PHDR gets defined by the configure

+   script. */

+#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \

+    && defined(TARGET_DL_ITERATE_PHDR)

+# define USE_PT_GNU_EH_FRAME

+#endif

+

 #if defined(USE_PT_GNU_EH_FRAME)

 

 #include <link.h>

Index: b/gcc/configure

===================================================================

--- a/gcc/configure

+++ b/gcc/configure

@@ -26787,6 +26787,9 @@

@@ -26791,6 +26791,9 @@

 else

   gcc_cv_libc_provides_ssp=no

     case "$target" in
@@ -348,7 +333,7 @@ Index: b/gcc/configure 
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)

       # glibc 2.4 and later provides __stack_chk_fail and

       # either __stack_chk_guard, or TLS access to stack guard canary.

@@ -26820,6 +26823,7 @@

@@ -26824,6 +26827,7 @@

 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now

 	 # simply assert that glibc does provide this, which is true for all

 	 # realistically usable GNU/Hurd configurations.
@@ -356,7 +341,7 @@ Index: b/gcc/configure 
 	 gcc_cv_libc_provides_ssp=yes;;

        *-*-darwin* | *-*-freebsd*)

 	 ac_fn_c_check_func "$LINENO" "__stack_chk_fail" "ac_cv_func___stack_chk_fail"

@@ -26902,6 +26906,9 @@

@@ -26906,6 +26910,9 @@

       gcc_cv_target_dl_iterate_phdr=no

     fi

     ;;
@@ -370,7 +355,7 @@ Index: b/gcc/configure.ac 
===================================================================

--- a/gcc/configure.ac

+++ b/gcc/configure.ac

@@ -4664,6 +4664,9 @@

@@ -4669,6 +4669,9 @@

       gcc_cv_libc_provides_ssp,

       [gcc_cv_libc_provides_ssp=no

     case "$target" in
@@ -380,7 +365,7 @@ Index: b/gcc/configure.ac 
        *-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)

       [# glibc 2.4 and later provides __stack_chk_fail and

       # either __stack_chk_guard, or TLS access to stack guard canary.

@@ -4697,6 +4700,7 @@

@@ -4702,6 +4705,7 @@

 	 # <http://gcc.gnu.org/ml/gcc/2008-10/msg00130.html>) and for now

 	 # simply assert that glibc does provide this, which is true for all

 	 # realistically usable GNU/Hurd configurations.
@@ -388,7 +373,7 @@ Index: b/gcc/configure.ac 
 	 gcc_cv_libc_provides_ssp=yes;;

        *-*-darwin* | *-*-freebsd*)

 	 AC_CHECK_FUNC(__stack_chk_fail,[gcc_cv_libc_provides_ssp=yes],

@@ -4762,6 +4766,9 @@

@@ -4767,6 +4771,9 @@

       gcc_cv_target_dl_iterate_phdr=no

     fi

     ;;