Fix the size of .rel.dyn on MIPS

Fix the size of .rel.dyn on MIPS

[Richard Sandiford]

A few years ago, when trying to get binutils to work on IRIX, I found
that the n64 rtld would ignore all dynamic relocations before an
R_MIPS_NONE entry.  Perhaps it walks back from the end of the
relocations to the beginning and assumes that the first null entry it
sees is the special null entry that starts the dynamic relocations.
(I think this would be ABI-conforming behaviour.)

Binutils sometimes allocates more dynamic relocations than it needs and
the unused slots are set to R_MIPS_NONE entries.  However, because of
the above IRIX problem, I'd changed DT_RELSZ so that it didn't count
those relocs.  This should also reduce dynamic linking time slightly.
However, I didn't change the size of the .rel.dyn section itself,
and the prelinker expects the two values to be the same.

Although it is possible to change the prelinker, I think the assumption
it makes is reasonable, and that this is really a fault in my IRIX patch.
Making .rel.dyn smaller will also make it more obvious that there is
spare room after the last useful relocation.  In some cases, that spare
room might even be enough for the prelinker to do an in-place
REL-to-RELA conversion.

Tested on mips{,64}{,el}-{elf,linux-gnu} and mips-sgi-irix6.5.
OK to install?

Richard


bfd/
	* elfxx-mips.c (_bfd_mips_elf_finish_dynamic_sections): Make the
	size of .rel.dyn reflect the value of DT_RELSZ.

ld/testsuite/
	* ld-mips-elf/multi-got-1.d: Remove trailing R_MIPS_NONE entries.
	* ld-mips-elf/tls-multi-got-1.got: Likewise.
	* ld-mips-elf/tls-multi-got-1.r: Likewise.

diff -udpr ../src.1/bfd/elfxx-mips.c ./bfd/elfxx-mips.c
--- ./bfd/elfxx-mips.c	2006-10-19 06:47:25.000000000 -0700
+++ ./bfd/elfxx-mips.c	2006-10-19 09:21:12.000000000 -0700
@@ -8873,6 +8873,10 @@ _bfd_mips_elf_finish_dynamic_sections (b
 				* (ABI_64_P (output_bfd)
 				   ? sizeof (Elf64_Mips_External_Rel)
 				   : sizeof (Elf32_External_Rel)));
+	      /* Adjust the section size too.  Tools like the prelinker
+		 can reasonably expect the values to the same.  */
+	      elf_section_data (s->output_section)->this_hdr.sh_size
+		= dyn.d_un.d_val;
 	      break;
 
 	    default:
diff -udpr ../src.1/ld/testsuite/ld-mips-elf/multi-got-1.d ./ld/testsuite/ld-mips-elf/multi-got-1.d
--- ./ld/testsuite/ld-mips-elf/multi-got-1.d	2006-10-19 06:47:25.000000000 -0700
+++ ./ld/testsuite/ld-mips-elf/multi-got-1.d	2006-10-19 09:22:43.000000000 -0700
@@ -25,7 +25,7 @@ Dynamic section at offset .* contains 17
  0x70000013 \(MIPS_GOTSYM\)                0x[0-9a-f]+
  0x00000000 \(NULL\)                       0x0
 
-Relocation section '\.rel\.dyn' at offset 0x[0-9a-f]+ contains 8203 entries:
+Relocation section '\.rel\.dyn' at offset 0x[0-9a-f]+ contains 8193 entries:
  Offset     Info    Type            Sym.Value  Sym. Name
 00000000  00000000 R_MIPS_NONE      
 ^[0-9a-f]+  [0-9a-f]+ R_MIPS_REL32      [0-9a-f]+   sym_2_[0-9]+
@@ -8220,13 +8220,3 @@ Relocation section '\.rel\.dyn' at offse
 ^[0-9a-f]+  [0-9a-f]+ R_MIPS_REL32      [0-9a-f]+   sym_2_[0-9]+
 ^[0-9a-f]+  [0-9a-f]+ R_MIPS_REL32      [0-9a-f]+   sym_2_[0-9]+
 ^[0-9a-f]+  [0-9a-f]+ R_MIPS_REL32      [0-9a-f]+   sym_2_[0-9]+
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
-00000000  00000000 R_MIPS_NONE      
diff -udpr ../src.1/ld/testsuite/ld-mips-elf/tls-multi-got-1.got ./ld/testsuite/ld-mips-elf/tls-multi-got-1.got
--- ./ld/testsuite/ld-mips-elf/tls-multi-got-1.got	2006-10-19 06:47:25.000000000 -0700
+++ ./ld/testsuite/ld-mips-elf/tls-multi-got-1.got	2006-10-19 09:24:11.000000000 -0700
@@ -15,28 +15,6 @@ OFFSET   TYPE              VALUE 
 00143f7c R_MIPS_REL32      sym_1_9526
 #...
 00139bd0 R_MIPS_REL32      sym_2_8654
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
-00000000 R_MIPS_NONE       \*ABS\*
 
 
 Contents of section .got:
diff -udpr ../src.1/ld/testsuite/ld-mips-elf/tls-multi-got-1.r ./ld/testsuite/ld-mips-elf/tls-multi-got-1.r
--- ./ld/testsuite/ld-mips-elf/tls-multi-got-1.r	2006-10-19 06:47:25.000000000 -0700
+++ ./ld/testsuite/ld-mips-elf/tls-multi-got-1.r	2006-10-19 09:23:11.000000000 -0700
@@ -20,7 +20,7 @@ Dynamic section at offset .* contains 18
  0x0000001e \(FLAGS\)                      STATIC_TLS
  0x00000000 \(NULL\)                       0x0
 
-Relocation section '\.rel\.dyn' at offset 0x[0-9a-f]+ contains 20031 entries:
+Relocation section '\.rel\.dyn' at offset 0x[0-9a-f]+ contains 20009 entries:
  Offset     Info    Type            Sym.Value  Sym. Name
 [0-9a-f ]+R_MIPS_NONE      
 [0-9a-f ]+R_MIPS_TLS_DTPMOD
@@ -36,4 +36,3 @@ Relocation section '\.rel\.dyn' at offse
 #...
 [0-9a-f ]+R_MIPS_REL32      000cf2b4   sym_1_0465
 [0-9a-f ]+R_MIPS_REL32      000e0ef8   sym_2_8654
-#...

Re: Fix the size of .rel.dyn on MIPS

[Eric Christopher]

>
> Tested on mips{,64}{,el}-{elf,linux-gnu} and mips-sgi-irix6.5.
> OK to install?
>

OK.

-eric