PATCH: Remove `.ctors' and `.dtors' output sections

["H.J. Lu" <hongjiu dot lu at intel dot com>]

Hi,

The Linux binutils 2.21.51.0.3 includes:

http://sourceware.org/ml/binutils/2010-12/msg00466.html

With the new linker, we can remove `.ctors' and `.dtors' output
sections.  Tested on Linux/ia32 and Linux/x86-64.


H.J.
---
2010-12-15  H.J. Lu  <hongjiu.lu@intel.com>

	* config.h.in (NO_CTORS_DTORS_SECTIONS): New.

	* configure.in: Define NO_CTORS_DTORS_SECTIONS if linker
	script has SORT_BY_INIT_PRIORITY.

	* elf/sofini.c: Remove `.ctors' and `.dtors' sections if
	NO_CTORS_DTORS_SECTIONS is defined.
	* elf/soinit.c: Likewise.

	* sysdeps/i386/init-first.c: Don't call __libc_global_ctors if
	NO_CTORS_DTORS_SECTIONS is defined.
	* sysdeps/mach/hurd/i386/init-first.c: Likewise.
	* sysdeps/mach/hurd/powerpc/init-first.c: Likewise.
	* sysdeps/sh/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/init-first.c: Likewise.

	* configure: Regenerated.

diff --git a/config.h.in b/config.h.in
index 18bf01a..9e797eb 100644
--- a/config.h.in
+++ b/config.h.in
@@ -201,6 +201,9 @@
 /* Define if multi-arch DSOs should be generated.  */
 #undef USE_MULTIARCH
 
+/* Define if `.ctors' and `.dtors' sections shouldn't be used.  */
+#undef	NO_CTORS_DTORS_SECTIONS
+
 /*
  */
 
diff --git a/configure b/configure
index eae35ba..fae71fb 100755
--- a/configure
+++ b/configure
@@ -6215,6 +6215,14 @@ fi
 $as_echo "$libc_cv_initfini_array" >&6; }
   if test $libc_cv_initfini_array != yes; then
     as_fn_error "Need linker with .init_array/.fini_array support." "$LINENO" 5
+  elif { ac_try='${CC-cc} -Wl,--verbose 2>&1|grep SORT_BY_INIT_PRIORITY 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then
+    $as_echo "#define NO_CTORS_DTORS_SECTIONS 1" >>confdefs.h
+
   fi
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libunwind-support in compiler" >&5
diff --git a/configure.in b/configure.in
index d8cd5f1..ad25b9b 100644
--- a/configure.in
+++ b/configure.in
@@ -1497,6 +1497,8 @@ EOF
   rm -f conftest*])
   if test $libc_cv_initfini_array != yes; then
     AC_MSG_ERROR([Need linker with .init_array/.fini_array support.])
+  elif AC_TRY_COMMAND([${CC-cc} -Wl,--verbose 2>&1|grep SORT_BY_INIT_PRIORITY 1>&AS_MESSAGE_LOG_FD]); then
+    AC_DEFINE(NO_CTORS_DTORS_SECTIONS)
   fi
 
   AC_CACHE_CHECK(for libunwind-support in compiler,
diff --git a/elf/sofini.c b/elf/sofini.c
index 5e06f0c..13e74b7 100644
--- a/elf/sofini.c
+++ b/elf/sofini.c
@@ -1,12 +1,14 @@
 /* Finalizer module for ELF shared C library.  This provides terminating
    null pointer words in the `.ctors' and `.dtors' sections.  */
 
+#ifndef NO_CTORS_DTORS_SECTIONS
 static void (*const __CTOR_END__[1]) (void)
      __attribute__ ((used, section (".ctors")))
      = { 0 };
 static void (*const __DTOR_END__[1]) (void)
      __attribute__ ((used, section (".dtors")))
      = { 0 };
+#endif
 
 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
    this would be the 'length' field in a real FDE.  */
diff --git a/elf/soinit.c b/elf/soinit.c
index 6fecbb5..1db676a 100644
--- a/elf/soinit.c
+++ b/elf/soinit.c
@@ -3,6 +3,7 @@
    the `.ctors' and `.dtors' sections so the lists are terminated, and
    calling those lists of functions.  */
 
+#ifndef NO_CTORS_DTORS_SECTIONS
 #include <libc-internal.h>
 #include <stdlib.h>
 
@@ -40,3 +41,4 @@ __libc_fini (void)
 
 void (*_fini_ptr) (void) __attribute__ ((section (".fini_array")))
      = &__libc_fini;
+#endif
diff --git a/sysdeps/i386/init-first.c b/sysdeps/i386/init-first.c
index c6355a8..2af042f 100644
--- a/sysdeps/i386/init-first.c
+++ b/sysdeps/i386/init-first.c
@@ -59,7 +59,9 @@ _init (int argc, ...)
 {
   init (&argc);
 
+#ifndef NO_CTORS_DTORS_SECTIONS
   __libc_global_ctors ();
+#endif
 }
 #endif
 
diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c
index f9a7a58..60823bd 100644
--- a/sysdeps/mach/hurd/i386/init-first.c
+++ b/sysdeps/mach/hurd/i386/init-first.c
@@ -92,7 +92,7 @@ posixland_init (int argc, char **argv, char **envp)
   __getopt_clean_environment (envp);
 #endif
 
-#ifdef SHARED
+#if defined SHARED && !defined NO_CTORS_DTORS_SECTIONS
   __libc_global_ctors ();
 #endif
 }
diff --git a/sysdeps/mach/hurd/powerpc/init-first.c b/sysdeps/mach/hurd/powerpc/init-first.c
index 20fa1d4..21b5054 100644
--- a/sysdeps/mach/hurd/powerpc/init-first.c
+++ b/sysdeps/mach/hurd/powerpc/init-first.c
@@ -82,7 +82,7 @@ posixland_init (int argc, char **argv, char **envp)
   __getopt_clean_environment (__environ);
 #endif
 
-#ifdef SHARED
+#if defined SHARED && !defined NO_CTORS_DTORS_SECTIONS
   __libc_global_ctors ();
 #endif
 }
diff --git a/sysdeps/sh/init-first.c b/sysdeps/sh/init-first.c
index d816625..1f3a821 100644
--- a/sysdeps/sh/init-first.c
+++ b/sysdeps/sh/init-first.c
@@ -59,7 +59,9 @@ _init (int argc, ...)
 {
   init (&argc);
 
+#ifndef NO_CTORS_DTORS_SECTIONS
   __libc_global_ctors ();
+#endif
 }
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/init-first.c b/sysdeps/unix/sysv/linux/init-first.c
index 7b2333d..a60212f 100644
--- a/sysdeps/unix/sysv/linux/init-first.c
+++ b/sysdeps/unix/sysv/linux/init-first.c
@@ -93,7 +93,7 @@ _init (int argc, char **argv, char **envp)
   __getopt_clean_environment (envp);
 #endif
 
-#ifdef SHARED
+#if defined SHARED && !defined NO_CTORS_DTORS_SECTIONS
   __libc_global_ctors ();
 #endif
 }