Re: [PATCH] program header instability

[Nathan Sidwell <nathan at codesourcery dot com>]

Alan Modra wrote:
> On Wed, Dec 27, 2006 at 04:59:56PM +0000, Nathan Sidwell wrote:
> > 	* bfd/elf.c (assign_file_positions_for_load_sections): We can
> > 	require fewer phdrs than expected.
> >
> > 	* ld/emultempl/elf-generic.em (gdl_map_segments): Only allow header
> > 	shrinkage for the first few iterations.
>
> OK.
>
> > 	* ld/testsuite/ld-elf/header.d: New.
> > 	* ld/testsuite/ld-elf/header.t: New.
> > 	* ld/testsuite/ld-elf/header.s: New.
>
> This fails on 64-bit targets.  I'll preapprove any necessary tweaks to
> make the test pass on at least powerpc64-linux and x86_64-linux.

corrected thusly and tested with powerpc64-linux cross tools

nathan

--
Nathan Sidwell    ::   http://www.codesourcery.com   ::         CodeSourcery
nathan@codesourcery.com    ::     http://www.planetfall.pwp.blueyonder.co.uk

Index: bfd/elf.c
===================================================================
RCS file: /cvs/src/src/bfd/elf.c,v
retrieving revision 1.369
diff -c -3 -p -r1.369 elf.c
*** bfd/elf.c	19 Dec 2006 08:49:38 -0000	1.369
--- bfd/elf.c	11 Jan 2007 12:19:56 -0000
*************** assign_file_positions_for_load_sections 
*** 4275,4281 ****
      elf_tdata (abfd)->program_header_size = alloc * bed->s->sizeof_phdr;
    else
      BFD_ASSERT (elf_tdata (abfd)->program_header_size
! 		== alloc * bed->s->sizeof_phdr);
  
    if (alloc == 0)
      {
--- 4275,4281 ----
      elf_tdata (abfd)->program_header_size = alloc * bed->s->sizeof_phdr;
    else
      BFD_ASSERT (elf_tdata (abfd)->program_header_size
! 		>= alloc * bed->s->sizeof_phdr);
  
    if (alloc == 0)
      {
Index: ld/emultempl/elf-generic.em
===================================================================
RCS file: /cvs/src/src/ld/emultempl/elf-generic.em,v
retrieving revision 1.3
diff -c -3 -p -r1.3 elf-generic.em
*** ld/emultempl/elf-generic.em	26 Jul 2006 12:27:12 -0000	1.3
--- ld/emultempl/elf-generic.em	11 Jan 2007 12:20:02 -0000
*************** gld${EMULATION_NAME}_map_segments (bfd_b
*** 60,66 ****
  	    einfo ("%F%P: map sections to segments failed: %E\n");
  
  	  if (phdr_size != elf_tdata (output_bfd)->program_header_size)
! 	    need_layout = TRUE;
  	}
      }
    while (need_layout && --tries);
--- 60,76 ----
  	    einfo ("%F%P: map sections to segments failed: %E\n");
  
  	  if (phdr_size != elf_tdata (output_bfd)->program_header_size)
! 	    {
! 	      if (tries > 6)
! 		/* The first few times we allow any change to
! 		   phdr_size .  */
! 		need_layout = TRUE;
! 	      else if (phdr_size < elf_tdata (output_bfd)->program_header_size)
! 		/* After that we only allow the size to grow.  */
! 		need_layout = TRUE;
! 	      else
! 		elf_tdata (output_bfd)->program_header_size = phdr_size;
! 	    }
  	}
      }
    while (need_layout && --tries);
Index: ld/testsuite/ld-elf/header.d
===================================================================
RCS file: ld/testsuite/ld-elf/header.d
diff -N ld/testsuite/ld-elf/header.d
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- ld/testsuite/ld-elf/header.d	11 Jan 2007 12:20:03 -0000
***************
*** 0 ****
--- 1,12 ----
+ # ld: -T header.t -z max-page-size=0x10000
+ # objdump: -hpw
+ 
+ #...
+ Program Header:
+     LOAD off    0x0*0000000 vaddr 0x0*0010000 paddr 0x0*0010000 align 2..16
+          filesz 0x0*001002[48] memsz 0x0*001002[48] flags rwx
+ 
+ Sections:
+ Idx Name          Size      VMA       *LMA       *File off  Algn  Flags
+   0 .text         0*000ffac  0*001007[48]  0*001007[48]  0*000007[48]  2...  CONTENTS, ALLOC, LOAD, READONLY, CODE
+   1 .data         0*0000004  0*002002[04]  0*002002[04]  0*001002[04]  2...  CONTENTS, ALLOC, LOAD, DATA
Index: ld/testsuite/ld-elf/header.s
===================================================================
RCS file: ld/testsuite/ld-elf/header.s
diff -N ld/testsuite/ld-elf/header.s
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- ld/testsuite/ld-elf/header.s	11 Jan 2007 12:20:03 -0000
***************
*** 0 ****
--- 1,8 ----
+ 	.text
+ 	.globl main
+ main:
+ 	.rept 0x4000 - 0x15
+ 	.long 0xfedcba98
+ 	.endr
+ 	.data
+ 	.long 0x76543210
Index: ld/testsuite/ld-elf/header.t
===================================================================
RCS file: ld/testsuite/ld-elf/header.t
diff -N ld/testsuite/ld-elf/header.t
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- ld/testsuite/ld-elf/header.t	11 Jan 2007 12:20:03 -0000
***************
*** 0 ****
--- 1,8 ----
+ ENTRY(main)
+ 
+ SECTIONS
+ {
+   . = 0x10000 + SIZEOF_HEADERS;
+   .text : { *(.text) }
+   .data : { *(.data) }
+ }