Re: [BUG?] GCC 4.5.2 produces deprecated ARM relocation

[Nick Clifton <nickc at redhat dot com>]

Hi Richard,

> > GCC is adding this suffix because the -fPIC flag enables NEED_PLT_RELOC
> > (see gcc/config/arm/elf.h).  Why elf.h is doing this I am not sure -
> > backwards compatibility maybe ?  Anyway it is GCC that needs fixing, not
> > GAS.

> I disagree, gas should just ignore the suffix when generating EABI
> conforming objects.

Well I based my conclusion upon this note in gas/doc/c-arm.texi:

   For compatibility with older toolchains the assembler
   also accepts @code{(PLT)} after branch targets.  This
   will generate the deprecated @samp{R_ARM_PLT32} relocation.

I do not mind enhancing the assembler however, so what do you think of 
the attached patch ?

Cheers
  Nick

gas/ChangeLog
2011-10-26  Nick Clifton  <nickc@redhat.com>

	* config/tc-arm.c (md_begin): Remove ARM_PLT32 reloc associated
	with the (PLT) instruction suffix when operating in eabi mode.
	* doc/c-arm.texi (ARM_Relocations): Extend description of (PLT)
	suffix.

Index: gas/config/tc-arm.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-arm.c,v
retrieving revision 1.502
diff -u -3 -p -r1.502 tc-arm.c
--- gas/config/tc-arm.c	18 Oct 2011 14:41:53 -0000	1.502
+++ gas/config/tc-arm.c	26 Oct 2011 12:03:34 -0000
@@ -32,7 +32,7 @@
 #include "safe-ctype.h"
 #include "subsegs.h"
 #include "obstack.h"
-
+#include "libiberty.h"
 #include "opcode/arm.h"
 
 #ifdef OBJ_ELF
@@ -22420,8 +22422,16 @@ md_begin (void)
     hash_insert (arm_barrier_opt_hsh, barrier_opt_names[i].template_name,
 		 (void *) (barrier_opt_names + i));
 #ifdef OBJ_ELF
-  for (i = 0; i < sizeof (reloc_names) / sizeof (struct reloc_entry); i++)
-    hash_insert (arm_reloc_hsh, reloc_names[i].name, (void *) (reloc_names + i));
+  for (i = 0; i < ARRAY_SIZE (reloc_names); i++)
+    {
+      struct reloc_entry * entry = reloc_names + i;
+
+      if (arm_is_eabi() && entry->reloc == BFD_RELOC_ARM_PLT32)
+	/* This makes encode_branch() use the EABI versions of this relocation.  */
+	entry->reloc = BFD_RELOC_UNUSED;
+
+      hash_insert (arm_reloc_hsh, entry->name, (void *) entry);
+    }
 #endif
 
   set_constant_flonums ();
Index: gas/doc/c-arm.texi
===================================================================
RCS file: /cvs/src/src/gas/doc/c-arm.texi,v
retrieving revision 1.85
diff -u -3 -p -r1.85 c-arm.texi
--- gas/doc/c-arm.texi	31 May 2011 14:12:54 -0000	1.85
+++ gas/doc/c-arm.texi	26 Oct 2011 12:03:34 -0000
@@ -493,8 +493,10 @@ and
 @code{TPOFF}.
 
 For compatibility with older toolchains the assembler also accepts
-@code{(PLT)} after branch targets.  This will generate the deprecated
-@samp{R_ARM_PLT32} relocation.
+@code{(PLT)} after branch targets.  On legacy targets this will
+generate the deprecated @samp{R_ARM_PLT32} relocation.  On EABI
+targets it will encode either the @samp{R_ARM_CALL} or
+@samp{R_ARM_JUMP24} relocation, as appropriate.
 
 @cindex MOVW and MOVT relocations, ARM
 Relocations for @samp{MOVW} and @samp{MOVT} instructions can be generated
Index: gas/testsuite/gas/arm/pic.d
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/arm/pic.d,v
retrieving revision 1.15
diff -u -3 -p -r1.15 pic.d
--- gas/testsuite/gas/arm/pic.d	7 Mar 2006 08:39:21 -0000	1.15
+++ gas/testsuite/gas/arm/pic.d	26 Oct 2011 12:03:34 -0000
@@ -13,7 +13,7 @@ Disassembly of section .text:
 00+0 <[^>]*> eb...... 	bl	00+. <[^>]*>
 			0: R_ARM_(PC24|CALL)	foo.*
 00+4 <[^>]*> eb...... 	bl	0[0123456789abcdef]+ <[^>]*>
-			4: R_ARM_PLT32	foo
+			4: R_ARM_(PLT32|CALL)	foo
 	\.\.\.
 			8: R_ARM_ABS32	sym
 			c: R_ARM_GOT32	sym