[PATCH + test RFA] MIPS/LD: Fix crashing with a discarded dynamic relocation section

[H.J. Lu]

On Fri, Jul 20, 2018 at 5:40 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Jul 20, 2018 at 5:30 AM, Maciej W. Rozycki <macro@mips.com> wrote:
>> Hi Nick,
>>
>>> Approved.  Better to have a testcase that fails than a problem that
>>> no-one knows about...
>>
>>  Applied then, thanks for the quick review.  I keep being confused about
>> our XFAIL policy (and myself I tend to forget about things that have been
>> XFAILed and never get back to them, so they never get fixed, unless
>> perhaps by chance if I come across the same problem elsewhere).
>>
>>   Maciej
>
> On x86-64, I got
>
> regexp_diff match failure
> regexp "^There are no dynamic relocations in this file\.$"
> line   "'RELA' relocation section at offset 0x70 contains 24 bytes:"
> extra lines in tmpdir/dump.out starting with "^  Offset          Info
>          Type           Sym. Value    Sym. Name + Addend$"
> EOF from /export/gnu/import/git/sources/binutils-gdb/ld/testsuite/ld-elf/reloc-discard.d
> FAIL: Discarded dynamic relocation section
>
> [hjl@gnu-cfl-1 ld]$ cat 1
> /export/build/gnu/binutils-gold/build-x86_64-linux/ld/../gas/as-new
> --defsym ALIGN=3   -o tmpdir/reloc-discard.o
> /export/gnu/import/git/sources/binutils-gdb/ld/testsuite/ld-elf/reloc-discard.s
> ./ld-new -z norelro
> -L/export/gnu/import/git/sources/binutils-gdb/ld/testsuite/ld-elf
> -shared -T reloc-discard.ld -o tmpdir/dump tmpdir/reloc-discard.o
> /export/build/gnu/binutils-gold/build-x86_64-linux/ld/../binutils/readelf
>  -r --use-dynamic tmpdir/dump
> [hjl@gnu-cfl-1 ld]$ sh 1
>
> 'RELA' relocation section at offset 0x70 contains 24 bytes:
>   Offset          Info           Type           Sym. Value    Sym. Name + Addend
> 000000000088  000100000001 R_X86_64_64       0000000000000000 foo + 0
> [hjl@gnu-cfl-1 ld]$
>
>
> --
> H.J.

diff --git a/ld/testsuite/ld-elf/reloc-discard.ld
b/ld/testsuite/ld-elf/reloc-discard.ld
index b16b80a242..1252bbb832 100644
--- a/ld/testsuite/ld-elf/reloc-discard.ld
+++ b/ld/testsuite/ld-elf/reloc-discard.ld
@@ -2,5 +2,5 @@ SECTIONS
 {
   /* .dynamic needs to go first with MIPS IRIX-style emulations.  */
   .dynamic : { *(.dynamic) }
-  /DISCARD/ : { *(.rel.dyn) *(.rela.dyn) }
                               ^^^^^^^^^^^^^^^^^^  This won't work on
output sections.

On many targets, .rel.dyn and .rela.dyn are output sections.

+  /DISCARD/ : { *(.rel.*) *(.rela.*) }
                           ^^^^^^^^^^^^^^^ This works.
 }


-- 
H.J.