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[PATCH] Extend -fno-plt to normal non-PIC branches on x86

This patch extends -fno-plt to normal non-PIC calls on x86.  -fno-plt
works in 64-bit mode with the existing binutils.  For 32-bit, we need
the updated assembler and linker to support "call/jmp *foo@GOT" with
a new relocation different from R_386_GOT32 to indicate that this
relocation applies to indirect branches.  A configure time check is
added to verify that 32-bit assembler generates a known relocation
which is different from R_386_GOT32.  A new 32-bit relocaton is needed
since "call/jmp *foo@GOT" requires a different relocation from R_386_GOT32
which is used together with a GOT register in "call/jmp *foo@GOT(%reg)".

OK for master?

Thanks.

H.J.
---
	* configure.ac (HAVE_AS_INDIRECT_BRANCH_VIA_GOT): New.  Defined
	if 32-bit assembler generates a known relocation which is
	different from R_386_GOT32.
	* config.in: Regenerated.
	* configure: Likewise.
	* config/i386/i386.c (ix86_output_call_insn):  Extend -fno-plt
	to normal non-PIC branches.
---
 gcc/config.in          | 14 ++++++++++----
 gcc/config/i386/i386.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 gcc/configure          | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 gcc/configure.ac       | 18 +++++++++++++++++-
 4 files changed, 113 insertions(+), 8 deletions(-)

diff --git a/gcc/config.in b/gcc/config.in
index daaf906..0ee5c38 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -363,6 +363,12 @@
 #endif
 
 
+/* Define true if the assembler supports 'call *foo@GOT'. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_AS_INDIRECT_BRANCH_VIA_GOT
+#endif
+
+
 /* Define if your assembler supports the Sun syntax for cmov. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_AS_IX86_CMOV_SUN_SYNTAX
@@ -686,8 +692,8 @@
 #endif
 
 
-/* Define to 1 if we found a declaration for 'basename', otherwise define to
-   0. */
+/* Define to 1 if you have the declaration of `basename(const char*)', and to
+   0 if you don't. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_DECL_BASENAME
 #endif
@@ -963,8 +969,8 @@
 #endif
 
 
-/* Define to 1 if we found a declaration for 'strstr', otherwise define to 0.
-   */
+/* Define to 1 if you have the declaration of `strstr(const char*,const
+   char*)', and to 0 if you don't. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_DECL_STRSTR
 #endif
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index e77cd04..5ca19f2 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -25611,7 +25611,26 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
   if (SIBLING_CALL_P (insn))
     {
       if (direct_p)
-	xasm = "%!jmp\t%P0";
+	{
+	  if (!flag_plt
+	      && !flag_pic
+	      && !TARGET_MACHO
+	      && !TARGET_SEH
+	      && !TARGET_PECOFF)
+	    {
+	      /* Avoid PLT.  */
+	      if (TARGET_64BIT)
+		xasm = "%!jmp\t*%p0@GOTPCREL(%%rip)";
+	      else
+#ifdef HAVE_AS_INDIRECT_BRANCH_VIA_GOT
+		xasm = "%!jmp\t*%p0@GOT";
+#else
+		xasm = "%!jmp\t%P0";
+#endif
+	    }
+	  else
+	    xasm = "%!jmp\t%P0";
+	}
       /* SEH epilogue detection requires the indirect branch case
 	 to include REX.W.  */
       else if (TARGET_SEH)
@@ -25654,7 +25673,26 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
     }
 
   if (direct_p)
-    xasm = "%!call\t%P0";
+    {
+      if (!flag_plt
+	  && !flag_pic
+	  && !TARGET_MACHO
+	  && !TARGET_SEH
+	  && !TARGET_PECOFF)
+	{
+	  /* Avoid PLT.  */
+	  if (TARGET_64BIT)
+	    xasm = "%!call\t*%p0@GOTPCREL(%%rip)";
+	  else
+#ifdef HAVE_AS_INDIRECT_BRANCH_VIA_GOT
+	    xasm = "%!call\t*%p0@GOT";
+#else
+	    xasm = "%!call\t%P0";
+#endif
+	}
+      else
+	xasm = "%!call\t%P0";
+    }
   else
     xasm = "%!call\t%A0";
 
diff --git a/gcc/configure b/gcc/configure
index a9a76d6..4419035 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -25361,7 +25361,7 @@ $as_echo "#define HAVE_AS_IX86_DIFF_SECT_DELTA 1" >>confdefs.h
 
 fi
 
-    # These two are used unconditionally by i386.[ch]; it is to be defined
+    # These three are used unconditionally by i386.[ch]; it is to be defined
     # to 1 if the feature is present, 0 otherwise.
     as_ix86_gotoff_in_data_opt=
     if test x$gas = xyes; then
@@ -25407,6 +25407,51 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+    as_ix86_indirect_branch_via_got_opt=
+    if test x$gas = xyes; then
+      as_ix86_indirect_branch_via_got_opt="--32"
+    fi
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for call *foo@GOT" >&5
+$as_echo_n "checking assembler for call *foo@GOT... " >&6; }
+if test "${gcc_cv_as_ix86_indirect_branch_via_got+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_as_ix86_indirect_branch_via_got=no
+    if test $in_tree_gas = yes; then
+    if test $gcc_cv_gas_vers -ge `expr \( \( 2 \* 1000 \) + 26 \) \* 1000 + 0`
+  then gcc_cv_as_ix86_indirect_branch_via_got=yes
+fi
+  elif test x$gcc_cv_as != x; then
+    $as_echo '	.text
+	call *foo@GOT' > conftest.s
+    if { ac_try='$gcc_cv_as $gcc_cv_as_flags $as_ix86_indirect_branch_via_got_opt -o conftest.o conftest.s >&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+	if test x$gcc_cv_readelf != x \
+	 && $gcc_cv_readelf -r conftest.o | grep R_386_ | grep -v R_386_GOT32 > /dev/null 2>&1; then
+	   gcc_cv_as_ix86_indirect_branch_via_got=yes
+	 fi
+    else
+      echo "configure: failed program was" >&5
+      cat conftest.s >&5
+    fi
+    rm -f conftest.o conftest.s
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_ix86_indirect_branch_via_got" >&5
+$as_echo "$gcc_cv_as_ix86_indirect_branch_via_got" >&6; }
+if test $gcc_cv_as_ix86_indirect_branch_via_got = yes; then
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_AS_INDIRECT_BRANCH_VIA_GOT 1
+_ACEOF
+
+fi
+
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for rep and lock prefix" >&5
 $as_echo_n "checking assembler for rep and lock prefix... " >&6; }
 if test "${gcc_cv_as_ix86_rep_lock_prefix+set}" = set; then :
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 83f9c09..543e650 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -3953,7 +3953,7 @@ foo:	nop
       [AC_DEFINE(HAVE_AS_IX86_DIFF_SECT_DELTA, 1,
         [Define if your assembler supports the subtraction of symbols in different sections.])])
 
-    # These two are used unconditionally by i386.[ch]; it is to be defined
+    # These three are used unconditionally by i386.[ch]; it is to be defined
     # to 1 if the feature is present, 0 otherwise.
     as_ix86_gotoff_in_data_opt=
     if test x$gas = xyes; then
@@ -3971,6 +3971,22 @@ foo:	nop
       [`if test $gcc_cv_as_ix86_gotoff_in_data = yes; then echo 1; else echo 0; fi`],
       [Define true if the assembler supports '.long foo@GOTOFF'.])
 
+    as_ix86_indirect_branch_via_got_opt=
+    if test x$gas = xyes; then
+      as_ix86_indirect_branch_via_got_opt="--32"
+    fi
+    gcc_GAS_CHECK_FEATURE([call *foo@GOT],
+      gcc_cv_as_ix86_indirect_branch_via_got, [2,26,0],
+      [$as_ix86_indirect_branch_via_got_opt],
+[	.text
+	call *foo@GOT],
+	[if test x$gcc_cv_readelf != x \
+	 && $gcc_cv_readelf -r conftest.o | grep R_386_ | grep -v R_386_GOT32 > /dev/null 2>&1; then
+	   gcc_cv_as_ix86_indirect_branch_via_got=yes
+	 fi],
+     [AC_DEFINE_UNQUOTED(HAVE_AS_INDIRECT_BRANCH_VIA_GOT, 1,
+       [Define true if the assembler supports 'call *foo@GOT'.])])
+
     gcc_GAS_CHECK_FEATURE([rep and lock prefix],
         gcc_cv_as_ix86_rep_lock_prefix,,,
 	[rep movsl
-- 
1.9.3
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