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PATCH: Replace @PLT with @GOTPCREL(%rip) in call
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Thu, 3 Mar 2016 05:20:55 -0800
- Subject: PATCH: Replace @PLT with @GOTPCREL(%rip) in call
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Since both PREINIT_FUNCTION and __libc_start_main are defined externally,
they are called via PLT. Use "call *func@GOTPCREL(%rip)" removes the
extra branch to PLT entry.
[BZ #19745]
* sysdeps/x86_64/crti.S (_init): Replace @PLT with
@GOTPCREL(%rip) in call.
* sysdeps/x86_64/start.S (_start): Likewise.
---
sysdeps/x86_64/crti.S | 2 +-
sysdeps/x86_64/start.S | 2 +-
sysdeps/x86_64/sysdep.h | 14 +++++++++++---
3 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/sysdeps/x86_64/crti.S b/sysdeps/x86_64/crti.S
index a345259..3dff141 100644
--- a/sysdeps/x86_64/crti.S
+++ b/sysdeps/x86_64/crti.S
@@ -66,7 +66,7 @@ _init:
movq PREINIT_FUNCTION@GOTPCREL(%rip), %rax
testq %rax, %rax
je .Lno_weak_fn
- call PREINIT_FUNCTION@PLT
+ call *PREINIT_FUNCTION@GOTPCREL(%rip)
.Lno_weak_fn:
#else
call PREINIT_FUNCTION
diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S
index 1374974..22b18ae 100644
--- a/sysdeps/x86_64/start.S
+++ b/sysdeps/x86_64/start.S
@@ -105,7 +105,7 @@ ENTRY (_start)
/* Call the user's main function, and exit with its value.
But let the libc call main. */
- call __libc_start_main@PLT
+ call *__libc_start_main@GOTPCREL(%rip)
#else
/* Pass address of our own entry points to .fini and .init. */
mov $__libc_csu_fini, %R8_LP