Re: [PATCH] Indicate dependency on personality routines for ARM EHABI- take 2

[Julian Brown <julian at codesourcery dot com>]

Paul Brook wrote:
> On Thursday 03 March 2005 22:43, Julian Brown wrote:
>
> > Hi,
> >
> > This is a second attempt at a patch to make gas emit dependencies on
> > exception-handling personality routines (__aeabi_unwind_cpp_pr[012]) in
> > accordance with the ARM EHABI, using relocations of type R_ARM_NONE.
> >
> > The previous patch is here:
> >
> >   http://sourceware.org/ml/binutils/2005-02/msg00172.html
> >
> > This version fixes some missing cases in the previous patch (eg, where
> > there is a .personalityindex directive in an assembly source file but
> > nothing is written to an .extab section), and outputs only one
> > relocation for each personality routine per-file to save unnecessary bloat.
>
>
> Is one per file sufficient? I'd expect one per section would be needed to 
> prevent bad things happening with partial linking.

Yes, you are probably right. This version should fix that: it resets the 
bitmap of relocations which have been output when the section is changed 
to one of type SHT_ARM_EXIDX.

Tested with cross to arm-none-eabi, and natively with all targets on 
i686-pc-unknown-none.

OK to apply?

ChangeLog:

    * gas/config/tc-arm.c (marked_pr_dependency): New static global
    (bitmask).
    (arm_elf_change_section): Reset bitmap of dependencies which have
    been output when a new EXIDX section is seen.
    (create_unwind_entry): Don't output dependencies on PR routines
    here.
    (s_arm_unwind_fnend): Output dependency on unwinding routines, if it
    hasn't been done already.
    * gas/testsuite/arm/unwind.d: Update expected output.

? bfd/doc/bfd.info
? bfd/doc/bfd.info-1
? gas/doc/as.info
? gas/doc/as.info-1
? gprof/gprof.info
? gprof/gprof.info-1
Index: gas/config/tc-arm.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-arm.c,v
retrieving revision 1.193
diff -c -p -r1.193 tc-arm.c
*** gas/config/tc-arm.c	23 Feb 2005 12:28:03 -0000	1.193
--- gas/config/tc-arm.c	4 Mar 2005 18:54:20 -0000
*************** static struct
*** 83,88 ****
--- 83,93 ----
    unsigned        sp_restored:1;
  } unwind;
  
+ /* Bit N indicates that an R_ARM_NONE relocation has been output for
+    __aeabi_unwind_cpp_prN already if set. This enables dependencies to be
+    emitted only once per file, to save unnecessary bloat.  */
+ static unsigned int marked_pr_dependency = 0;
+ 
  #endif /* OBJ_ELF */
  
  enum arm_float_abi
*************** arm_elf_change_section (void)
*** 1376,1385 ****
  {
    flagword flags;
  
!   /* Link an unlinked unwind index table section to the .text section.  */
!   if (elf_section_type (now_seg) == SHT_ARM_EXIDX
!       && elf_linked_to_section (now_seg) == NULL)
!     elf_linked_to_section (now_seg) = text_section;
  
    if (!SEG_NORMAL (now_seg))
      return;
--- 1381,1394 ----
  {
    flagword flags;
  
!   if (elf_section_type (now_seg) == SHT_ARM_EXIDX)
!     {
!       /* Link an unlinked unwind index table section to the .text section.  */
!       if (elf_linked_to_section (now_seg) == NULL)
! 	elf_linked_to_section (now_seg) = text_section;
! 
!       marked_pr_dependency = 0;
!     }
  
    if (!SEG_NORMAL (now_seg))
      return;
*************** create_unwind_entry (int have_data)
*** 13902,13914 ****
        fix_new (frag_now, where, 4, unwind.personality_routine, 0, 1,
  	       BFD_RELOC_ARM_PREL31);
  
-       /* Indicate dependency to linker.  */
-         {
-           char *name = "__aeabi_unwind_cpp_pr0";
- 	  symbolS *pr = symbol_find_or_make (name);
- 	  fix_new (frag_now, where, 4, pr, 0, 1, BFD_RELOC_NONE);
- 	}
- 
        where += 4;
        ptr += 4;
  
--- 13911,13916 ----
*************** create_unwind_entry (int have_data)
*** 13922,13945 ****
        /* Three opcodes bytes are packed into the first word.  */
        data = 0x80;
        n = 3;
!       goto emit_reloc;
  
      case 1:
      case 2:
        /* The size and first two opcode bytes go in the first word.  */
        data = ((0x80 + unwind.personality_index) << 8) | size;
        n = 2;
-       goto emit_reloc;
- 
-     emit_reloc:
-       {
- 	/* Indicate dependency to linker.  */
- 	char *name[] = { "__aeabi_unwind_cpp_pr0",
- 	                 "__aeabi_unwind_cpp_pr1",
- 			 "__aeabi_unwind_cpp_pr2" };
- 	symbolS *pr = symbol_find_or_make (name[unwind.personality_index]);
- 	fix_new (frag_now, where, 4, pr, 0, 1, BFD_RELOC_NONE);
-       }
        break;
  
      default:
--- 13924,13936 ----
        /* Three opcodes bytes are packed into the first word.  */
        data = 0x80;
        n = 3;
!       break;
  
      case 1:
      case 2:
        /* The size and first two opcode bytes go in the first word.  */
        data = ((0x80 + unwind.personality_index) << 8) | size;
        n = 2;
        break;
  
      default:
*************** s_arm_unwind_fnend (int ignored ATTRIBUT
*** 14048,14053 ****
--- 14039,14059 ----
    fix_new (frag_now, where, 4, unwind.proc_start, 0, 1,
  	   BFD_RELOC_ARM_PREL31);
  
+   /* Indicate dependency on EHABI-defined personality routines to the 
+      linker, if it hasn't been done already.  */
+   if (unwind.personality_index >= 0 && unwind.personality_index < 3)
+     {
+       char *name[] = { "__aeabi_unwind_cpp_pr0",
+ 		       "__aeabi_unwind_cpp_pr1",
+ 		       "__aeabi_unwind_cpp_pr2" };
+       if (!(marked_pr_dependency & (1 << unwind.personality_index)))
+ 	{
+ 	  symbolS *pr = symbol_find_or_make (name[unwind.personality_index]);
+ 	  fix_new (frag_now, where, 0, pr, 0, 1, BFD_RELOC_NONE);
+ 	  marked_pr_dependency |= 1 << unwind.personality_index;
+ 	}
+     }
+ 
    if (val)
      /* Inline exception table entry.  */
      md_number_to_chars (ptr + 4, val, 4);
Index: gas/testsuite/gas/arm/unwind.d
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/arm/unwind.d,v
retrieving revision 1.4
diff -c -p -r1.4 unwind.d
*** gas/testsuite/gas/arm/unwind.d	10 Feb 2005 12:39:17 -0000	1.4
--- gas/testsuite/gas/arm/unwind.d	4 Mar 2005 18:54:22 -0000
***************
*** 5,20 ****
  
  RELOCATION RECORDS FOR \[.ARM.extab\]:
  OFFSET   TYPE              VALUE 
- 00000000 R_ARM_NONE        __aeabi_unwind_cpp_pr1
  0000000c R_ARM_PREL31      .text
- 0000000c R_ARM_NONE        __aeabi_unwind_cpp_pr0
- 0000001c R_ARM_NONE        __aeabi_unwind_cpp_pr1
  
  
  RELOCATION RECORDS FOR \[.ARM.exidx\]:
  OFFSET   TYPE              VALUE 
  00000000 R_ARM_PREL31      .text
  00000008 R_ARM_PREL31      .text
  0000000c R_ARM_PREL31      .ARM.extab
  00000010 R_ARM_PREL31      .text
  00000014 R_ARM_PREL31      .ARM.extab
--- 5,19 ----
  
  RELOCATION RECORDS FOR \[.ARM.extab\]:
  OFFSET   TYPE              VALUE 
  0000000c R_ARM_PREL31      .text
  
  
  RELOCATION RECORDS FOR \[.ARM.exidx\]:
  OFFSET   TYPE              VALUE 
  00000000 R_ARM_PREL31      .text
+ 00000000 R_ARM_NONE        __aeabi_unwind_cpp_pr0
  00000008 R_ARM_PREL31      .text
+ 00000008 R_ARM_NONE        __aeabi_unwind_cpp_pr1
  0000000c R_ARM_PREL31      .ARM.extab
  00000010 R_ARM_PREL31      .text
  00000014 R_ARM_PREL31      .ARM.extab