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VMA section overlap warnings for overlays

Alan Modra amodra@gmail.com
Thu Apr 22 01:53:00 GMT 2010 
On Thu, Apr 22, 2010 at 10:41:06AM +0930, Alan Modra wrote:
> Now we have a problem.  If we put .overlay1 in imem at p_offset+1 then
> the execution model lma (calculated from p_paddr+p_offset+1) for
> .overlay1 will be correct, but the vma (from p_vaddr+p_offset+1
> ie. 0x2001) will be wrong.  Of course, with multiple overlays packed
> into one header you can't possibly get the execution model vma correct
> for all the overlays, so you probably don't care.  However, the
> ELF_IS_SECTION_IN_SEGMENT_FILE test in
> elf.c:assign_file_positions_for_load_sections fails, which is why you
> get a linker error.
> 
> Conversely, putting .overlay1 at p_offset+0x2000 will give the correct
> vma but the wrong lma, and of course insert a whole lot of padding.
> This is what Jan's patch did, and is quite wrong for overlays..

Committed.  I didn't see any occurrence of the problem Jan originally
reported in http://sourceware.org/ml/binutils/2008-05/msg00235.html on
i386 or powerpc using recent compilers so perhaps some other change
cured it.

bfd/
	* elf.c (assign_file_positions_for_load_sections): Revert 2008-05-29
	change.  Tidy.  Don't error on sections not allocated in segment.
ld/testsuite/
	* ld-elf/extract-symbol-1sec.d: Update lma.
	* ld-i386/alloc.d: Expect a warning, not an error.

Index: bfd/elf.c
===================================================================
RCS file: /cvs/src/src/bfd/elf.c,v
retrieving revision 1.508
diff -u -p -r1.508 elf.c
--- bfd/elf.c	10 Apr 2010 22:21:31 -0000	1.508
+++ bfd/elf.c	22 Apr 2010 01:10:22 -0000
@@ -4453,32 +4453,17 @@ assign_file_positions_for_load_sections 
 		      && ((this_hdr->sh_flags & SHF_TLS) == 0
 			  || p->p_type == PT_TLS))))
 	    {
-	      bfd_signed_vma adjust = sec->vma - (p->p_vaddr + p->p_memsz);
+	      bfd_vma adjust = sec->lma - (p->p_paddr + p->p_memsz);
 
-	      if (sec->vma < p->p_vaddr + p->p_memsz)
+	      if (sec->lma < p->p_paddr + p->p_memsz)
 		{
 		  (*_bfd_error_handler)
-		    (_("%B: section %A vma 0x%lx overlaps previous sections"),
-		     abfd, sec, (unsigned long) sec->vma);
+		    (_("%B: section %A lma 0x%lx overlaps previous sections"),
+		     abfd, sec, (unsigned long) sec->lma);
 		  adjust = 0;
-		}
-	      p->p_memsz += adjust;
-
-	      if (p->p_paddr + p->p_memsz != sec->lma)
-		{
-		  /* This behavior is a compromise--ld has long
-		     silently changed the lma of sections when
-		     lma - vma is not equal for every section in a
-		     pheader--but only in the internal elf structures.
-		     Silently changing the lma is probably a bug, but
-		     changing it would have subtle and unknown
-		     consequences for existing scripts.
-
-		     Instead modify the bfd data structure to reflect
-		     what happened.  This at least fixes the values
-		     for the lma in the mapfile.  */
 		  sec->lma = p->p_paddr + p->p_memsz;
 		}
+	      p->p_memsz += adjust;
 
 	      if (this_hdr->sh_type != SHT_NOBITS)
 		{
@@ -4581,8 +4566,6 @@ assign_file_positions_for_load_sections 
 		  (_("%B: section `%A' can't be allocated in segment %d"),
 		   abfd, sec, j);
 		print_segment_map (m);
-		bfd_set_error (bfd_error_bad_value);
-		return FALSE;
 	      }
 	  }
     }
Index: ld/testsuite/ld-elf/extract-symbol-1sec.d
===================================================================
RCS file: /cvs/src/src/ld/testsuite/ld-elf/extract-symbol-1sec.d,v
retrieving revision 1.5
diff -u -p -r1.5 extract-symbol-1sec.d
--- ld/testsuite/ld-elf/extract-symbol-1sec.d	18 Nov 2009 16:37:55 -0000	1.5
+++ ld/testsuite/ld-elf/extract-symbol-1sec.d	22 Apr 2010 01:10:22 -0000
@@ -8,7 +8,7 @@
 #...
 Sections:
  *Idx +Name +Size +VMA +LMA .*
- *0 +\.foo +0+ +0+10000 +0+ .*
+ *0 +\.foo +0+ +0+10000 +0+10000 .*
  *CONTENTS, ALLOC, LOAD, CODE
  *1 +\.bar +0+ +0+20000 +0+10000 .*
  *ALLOC, READONLY, CODE
Index: ld/testsuite/ld-i386/alloc.d
===================================================================
RCS file: /cvs/src/src/ld/testsuite/ld-i386/alloc.d,v
retrieving revision 1.1
diff -u -p -r1.1 alloc.d
--- ld/testsuite/ld-i386/alloc.d	22 Mar 2007 15:50:38 -0000	1.1
+++ ld/testsuite/ld-i386/alloc.d	22 Apr 2010 01:33:24 -0000
@@ -1,4 +1,4 @@
 #name: Invalid allocated section
 #as: --32
 #ld: -melf_i386 -T alloc.t
-#error: .*section `.foo' can't be allocated in segment 0.*
+#warning: .*section `.foo' can't be allocated in segment 0.*

-- 
Alan Modra
Australia Development Lab, IBM
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