Don't use multi byte nop instructions for i386

bfd/

2012-02-09  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/13675
	* cpu-i386.c (bfd_arch_i386_fill): Updated to support multi byte
	nop instructions.
	(bfd_arch_i386_short_nop_fill): New.
	(bfd_arch_i386_long_nop_fill): Likewise.
	Use bfd_arch_i386_short_nop_fill in 32bit bfd_arch_info
	initializers.  Use bfd_arch_i386_long_nop_fill on 64bit
	bfd_arch_info initializers.

	* cpu-k1om.c (bfd_arch_i386_fill): Renamed to ...
	(bfd_arch_i386_short_nop_fill): This.
	Update bfd_arch_info initializers.
	* cpu-l1om.c: Likewise.

ld/testsuite/

2012-02-09  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/13675
	* ld-i386/tlsnopic.dd: Update no-op padding.
	* ld-i386/tlspic.dd: Likewise.

1 files changed, 40 insertions, 18 deletions

diff --git a/bfd/cpu-i386.c b/bfd/cpu-i386.c
index f8991cf1ec..4cb59ed898 100644
--- a/bfd/cpu-i386.c
+++ b/bfd/cpu-i386.c
@@ -25,7 +25,8 @@
 #include "libbfd.h"
 #include "libiberty.h"
 
-extern void * bfd_arch_i386_fill (bfd_size_type, bfd_boolean, bfd_boolean);
+extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bfd_boolean,
+					    bfd_boolean);
 
 static const bfd_arch_info_type *
 bfd_i386_compatible (const bfd_arch_info_type *a,
@@ -41,16 +42,16 @@ bfd_i386_compatible (const bfd_arch_info_type *a,
   return compat;
 }
 
-/* Fill the buffer with zero or nop instruction if CODE is TRUE.  */
+/* Fill the buffer with zero or nop instruction if CODE is TRUE.  Use
+   multi byte nop instructions if LONG_NOP is TRUE.  */
 
-void *
-bfd_arch_i386_fill (bfd_size_type count,
-		    bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
-		    bfd_boolean code)
+static void *
+bfd_arch_i386_fill (bfd_size_type count, bfd_boolean code,
+		    bfd_boolean long_nop)
 {
   /* nop */
   static const char nop_1[] = { 0x90 };	
-  /* nopw */
+  /* xchg %ax,%ax */
   static const char nop_2[] = { 0x66, 0x90 };
   /* nopl (%[re]ax) */
   static const char nop_3[] = { 0x0f, 0x1f, 0x00 };
@@ -74,6 +75,7 @@ bfd_arch_i386_fill (bfd_size_type count,
   static const char *const nops[] =
     { nop_1, nop_2, nop_3, nop_4, nop_5,
       nop_6, nop_7, nop_8, nop_9, nop_10 };
+  bfd_size_type nop_size = long_nop ? ARRAY_SIZE (nops) : 2;
 
   void *fill = bfd_malloc (count);
   if (fill == NULL)
@@ -82,11 +84,11 @@ bfd_arch_i386_fill (bfd_size_type count,
   if (code)
     {
       bfd_byte *p = fill;
-      while (count >= ARRAY_SIZE (nops))
+      while (count >= nop_size)
 	{
-	  memcpy (p, nops[ARRAY_SIZE (nops) - 1], ARRAY_SIZE (nops));
-	  p += ARRAY_SIZE (nops);
-	  count -= ARRAY_SIZE (nops);
+	  memcpy (p, nops[nop_size - 1], nop_size);
+	  p += nop_size;
+	  count -= nop_size;
 	}
       if (count != 0)
 	memcpy (p, nops[count - 1], count);
@@ -97,6 +99,26 @@ bfd_arch_i386_fill (bfd_size_type count,
   return fill;
 }
 
+/* Fill the buffer with zero or short nop instruction if CODE is TRUE.  */
+
+void *
+bfd_arch_i386_short_nop_fill (bfd_size_type count,
+			      bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
+			      bfd_boolean code)
+{
+  return bfd_arch_i386_fill (count, code, FALSE);
+}
+
+/* Fill the buffer with zero or long nop instruction if CODE is TRUE.  */
+
+static void *
+bfd_arch_i386_long_nop_fill (bfd_size_type count,
+			     bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
+			     bfd_boolean code)
+{
+  return bfd_arch_i386_fill (count, code, TRUE);
+}
+
 static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
 {
   64, /* 64 bits in a word */
@@ -110,7 +132,7 @@ static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
   FALSE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
   0
 };
 
@@ -127,7 +149,7 @@ static const bfd_arch_info_type bfd_x86_64_arch_intel_syntax =
   FALSE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
   &bfd_x64_32_arch_intel_syntax,
 };
 
@@ -144,7 +166,7 @@ static const bfd_arch_info_type bfd_i386_arch_intel_syntax =
   TRUE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
   &bfd_x86_64_arch_intel_syntax
 };
 
@@ -161,7 +183,7 @@ static const bfd_arch_info_type i8086_arch =
   FALSE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
   &bfd_i386_arch_intel_syntax
 };
 
@@ -178,7 +200,7 @@ static const bfd_arch_info_type bfd_x64_32_arch =
   FALSE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
   &i8086_arch
 };
 
@@ -195,7 +217,7 @@ static const bfd_arch_info_type bfd_x86_64_arch =
   FALSE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_long_nop_fill,
   &bfd_x64_32_arch
 };
 
@@ -212,6 +234,6 @@ const bfd_arch_info_type bfd_i386_arch =
   TRUE,
   bfd_i386_compatible,
   bfd_default_scan,
-  bfd_arch_i386_fill,
+  bfd_arch_i386_short_nop_fill,
   &bfd_x86_64_arch
 };