Fix an ARM unwinding table corner case

[Daniel Jacobowitz]

The current assembler will emit 0x8000 for a .save instruction which only
saves r0-r3.  No 0x8bbb opcode is needed here, and that particular one is
"can not unwind" with none of the low bits set.

OK?

-- 
Daniel Jacobowitz
CodeSourcery, LLC

2005-11-11  Daniel Jacobowitz  <dan@codesourcery.com>

	* config/tc-arm.c (s_arm_unwind_save_core): Don't emit an extra
	opcode if r4-r15 are not saved.

2005-11-11  Daniel Jacobowitz  <dan@codesourcery.com>

	* gas/arm/unwind.s, gas/arm/unwind.d, gas/arm/unwind_vxworks.d: Add
	a test for saving only the low registers.

Index: src/gas/config/tc-arm.c
===================================================================
--- src.orig/gas/config/tc-arm.c	2005-10-18 17:26:46.000000000 -0400
+++ src/gas/config/tc-arm.c	2005-11-09 15:26:21.000000000 -0500
@@ -2248,30 +2248,34 @@ s_arm_unwind_save_core (void)
       unwind.pending_offset = 0;
     }
 
-  /* See if we can use the short opcodes.  These pop a block of upto 8
-     registers starting with r4, plus maybe r14.  */
-  for (n = 0; n < 8; n++)
+  /* Pop r4-r15.  */
+  if (range & 0xfff0)
     {
-      /* Break at the first non-saved register.	 */
-      if ((range & (1 << (n + 4))) == 0)
-	break;
-    }
-  /* See if there are any other bits set.  */
-  if (n == 0 || (range & (0xfff0 << n) & 0xbff0) != 0)
-    {
-      /* Use the long form.  */
-      op = 0x8000 | ((range >> 4) & 0xfff);
-      add_unwind_opcode (op, 2);
-    }
-  else
-    {
-      /* Use the short form.  */
-      if (range & 0x4000)
-	op = 0xa8; /* Pop r14.	*/
+      /* See if we can use the short opcodes.  These pop a block of up to 8
+	 registers starting with r4, plus maybe r14.  */
+      for (n = 0; n < 8; n++)
+	{
+	  /* Break at the first non-saved register.	 */
+	  if ((range & (1 << (n + 4))) == 0)
+	    break;
+	}
+      /* See if there are any other bits set.  */
+      if (n == 0 || (range & (0xfff0 << n) & 0xbff0) != 0)
+	{
+	  /* Use the long form.  */
+	  op = 0x8000 | ((range >> 4) & 0xfff);
+	  add_unwind_opcode (op, 2);
+	}
       else
-	op = 0xa0; /* Do not pop r14.  */
-      op |= (n - 1);
-      add_unwind_opcode (op, 1);
+	{
+	  /* Use the short form.  */
+	  if (range & 0x4000)
+	    op = 0xa8; /* Pop r14.	*/
+	  else
+	    op = 0xa0; /* Do not pop r14.  */
+	  op |= (n - 1);
+	  add_unwind_opcode (op, 1);
+	}
     }
 
   /* Pop r0-r3.	 */
Index: src/gas/testsuite/gas/arm/unwind.d
===================================================================
--- src.orig/gas/testsuite/gas/arm/unwind.d	2005-10-18 17:26:50.000000000 -0400
+++ src/gas/testsuite/gas/arm/unwind.d	2005-11-09 15:34:00.000000000 -0500
@@ -24,11 +24,12 @@ OFFSET   TYPE              VALUE 
 00000018 R_ARM_PREL31      .text.*
 0000001c R_ARM_PREL31      .ARM.extab.*
 00000020 R_ARM_PREL31      .text.*
+00000028 R_ARM_PREL31      .text.*
 
 
 Contents of section .text:
  0000 (0000a0e3 0100a0e3 0200a0e3 0300a0e3|e3a00000 e3a00001 e3a00002 e3a00003)  .*
- 0010 (0420|2004)                                 .*
+ 0010 (04200520|20052004)                             .*
 Contents of section .ARM.extab:
  0000 (449b0181 b0b08086|81019b44 8680b0b0) 00000000 00000000  .*
  0010 (8402b101 b0b0b005 2a000000 00c60181|01b10284 05b0b0b0 0000002a 8101c600)  .*
@@ -36,6 +37,6 @@ Contents of section .ARM.extab:
 Contents of section .ARM.exidx:
  0000 00000000 (b0b0a880 04000000|80a8b0b0 00000004) 00000000  .*
  0010 (08000000 0c000000 0c000000 1c000000|00000008 0000000c 0000000c 0000001c)  .*
- 0020 (10000000 08849780|00000010 80978408)                    .*
+ 0020 (10000000 08849780 12000000 b00fb180|00000010 80978408 00000012 80b10fb0)  .*
 # Ignore .ARM.attributes section
 #...
Index: src/gas/testsuite/gas/arm/unwind.s
===================================================================
--- src.orig/gas/testsuite/gas/arm/unwind.s	2004-10-05 09:51:40.000000000 -0400
+++ src/gas/testsuite/gas/arm/unwind.s	2005-11-09 15:30:48.000000000 -0500
@@ -44,3 +44,8 @@ foo4:	@ Thumb frame pointer
 	@sub sp, sp, #8
 	mov r0, #4
 	.fnend
+foo5:	@ Save r0-r3 only.
+	.fnstart
+	.save {r0, r1, r2, r3}
+	mov r0, #5
+	.fnend
Index: src/gas/testsuite/gas/arm/unwind_vxworks.d
===================================================================
--- src.orig/gas/testsuite/gas/arm/unwind_vxworks.d	2005-07-04 10:57:45.000000000 -0400
+++ src/gas/testsuite/gas/arm/unwind_vxworks.d	2005-11-09 15:37:46.000000000 -0500
@@ -25,11 +25,12 @@ OFFSET   TYPE              VALUE 
 00000018 R_ARM_PREL31      .text.*
 0000001c R_ARM_PREL31      .ARM.extab.*
 00000020 R_ARM_PREL31      .text.*
+00000028 R_ARM_PREL31      .text.*
 
 
 Contents of section .text:
  0000 (0000a0e3 0100a0e3 0200a0e3 0300a0e3|e3a00000 e3a00001 e3a00002 e3a00003)  .*
- 0010 (0420|2004)                                 .*
+ 0010 (04200520|20052004)                             .*
 Contents of section .ARM.extab:
  0000 (449b0181 b0b08086|81019b44 8680b0b0) 00000000 00000000  .*
  0010 (8402b101 b0b0b005 2a000000 00c60181|01b10284 05b0b0b0 0000002a 8101c600)  .*
@@ -37,4 +38,6 @@ Contents of section .ARM.extab:
 Contents of section .ARM.exidx:
  0000 00000000 (b0b0a880 00000000|80a8b0b0 00000000) 00000000  .*
  0010 00000000 00000000 00000000 00000000  .*
- 0020 (00000000 08849780|00000000 80978408)                    .*
+ 0020 (00000000 08849780 00000000 b00fb180|00000000 80978408 00000000 80b10fb0)  .*
+# Ignore .ARM.attributes section
+#...