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Re: [PATCH] Improve targetm.binds_local_p for common symbols on s390*/arm/aarch64 (PR target/65780)




On 23/04/15 17:36, Jakub Jelinek wrote:
Hi!

This patch undoes the PR65780 performance regressions on a few targets
I have tested to work fine.
This PR was about an access to uninitialized COMMON symbol defined in
executable (or PIE) where there is a normal symbol definition in a shared
library.  The PR65780 fix that got committed stopped treating
such COMMONs as binding local on all architectures, except for i?86 (for
normal execs only) and x86_64 (for normal execs and PIEs, but the latter
only with recent linker).  As s390/arm/aarch64 seems to work fine
(generate a COPY relocation and thus define symbol locally) in non-PIE
executables, this patch changes those to a function that has been added for
that behavior.  E.g. powerpc64{,le} on the other side isn't able to link
that case neither in normal execs nor PIEs.

Bootstrapped/regtested on
{x86_64,i686,armv7hl,aarch64,s390{,x},powerpc64{,le}}-linux, ok for trunk
(and perhaps after a while for 5.2)?

The ARM bits are OK.

regards
Ramana



2015-04-23  Jakub Jelinek  <jakub@redhat.com>

	PR target/65780
	* config/s390/linux.h (TARGET_BINDS_LOCAL_P): Define to
	default_binds_local_p_2.
	* config/arm/linux-elf.h (TARGET_BINDS_LOCAL_P): Likewise.
	* config/aarch64/aarch64-linux.h (TARGET_BINDS_LOCAL_P): Likewise.

--- gcc/config/s390/linux.h.jj	2015-01-05 13:07:16.000000000 +0100
+++ gcc/config/s390/linux.h	2015-04-22 17:39:38.880273650 +0200
@@ -90,4 +90,10 @@ along with GCC; see the file COPYING3.
  #undef TARGET_LIBC_HAS_FUNCTION
  #define TARGET_LIBC_HAS_FUNCTION gnu_libc_has_function

+/* Uninitialized common symbols in non-PIE executables, even with
+   strong definitions in dependent shared libraries, will resolve
+   to COPY relocated symbol in the executable.  See PR65780.  */
+#undef TARGET_BINDS_LOCAL_P
+#define TARGET_BINDS_LOCAL_P default_binds_local_p_2
+
  #endif
--- gcc/config/arm/linux-elf.h.jj	2015-01-05 13:07:16.000000000 +0100
+++ gcc/config/arm/linux-elf.h	2015-04-22 17:42:35.979420149 +0200
@@ -118,3 +118,9 @@
  /* Add .note.GNU-stack.  */
  #undef NEED_INDICATE_EXEC_STACK
  #define NEED_INDICATE_EXEC_STACK	1
+
+/* Uninitialized common symbols in non-PIE executables, even with
+   strong definitions in dependent shared libraries, will resolve
+   to COPY relocated symbol in the executable.  See PR65780.  */
+#undef TARGET_BINDS_LOCAL_P
+#define TARGET_BINDS_LOCAL_P default_binds_local_p_2
--- gcc/config/aarch64/aarch64-linux.h.jj	2015-01-05 13:07:17.000000000 +0100
+++ gcc/config/aarch64/aarch64-linux.h	2015-04-22 17:40:46.395185820 +0200
@@ -69,4 +69,10 @@

  #define TARGET_ASM_FILE_END file_end_indicate_exec_stack

+/* Uninitialized common symbols in non-PIE executables, even with
+   strong definitions in dependent shared libraries, will resolve
+   to COPY relocated symbol in the executable.  See PR65780.  */
+#undef TARGET_BINDS_LOCAL_P
+#define TARGET_BINDS_LOCAL_P default_binds_local_p_2
+
  #endif  /* GCC_AARCH64_LINUX_H */

	Jakub



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