[GOLD] question about gold handling SPARC style .rela.plt, .rela.plt overlapping

["WANG.Jiong" <wong dot kwongyuan at gmail dot com>]

Hi David & Ian,

  currently, I am porting gold linker for a private target which allow 
PLTREL overlapping

  so, I met exactly the same problem as you have discussed two years ago

  http://sourceware.org/ml/binutils/2010-02/msg00140.html

  I see you have done a fix with the following logic:

  1. .rela.dyn,  .rela.plt are seperate
  2. generate DT_RELA only when there is .rela.dyn, and DT_RELASZ be 
the total size of both .rela.dyn and .rela.plt

  But, If there is no .rela.dyn, without DT_RELA, it seems dynamic 
linker behave incorrectly when ELF_MACHINE_PLTREL_OVERLAP defined

  I checked the implementation of  _ELF_DYNAMIC_DO_RELOC in glib

  elf/dynamic-link.h:260
  # define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, 
skip_ifunc, test_rel)

  without DT_REL or DT_RELA,  ranges[0] are not initialized properly.

  So, should we always generate DT_RELA, DT_RELASZ, DT_RELAENT, and 
make DT_RELA, DT_RELASZ exactly the same value as DT_JMPREL, DT_PLTRELSZ ?

  that is, for the following condition check in 
Layout::add_target_dynamic_tags

4344   if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
4345 {
4346       odyn->add_section_address(use_rel ? elfcpp::DT_REL : 
elfcpp::DT_RELA,
4347 dyn_rel->output_section());
4348       if (plt_rel != NULL
4349           && plt_rel->output_section() != NULL
4350           && dynrel_includes_plt)

   should we check dynrel_includes_plt even when dyn_rel == NULL ?

  or I have misunderstood something ?

  thanks very much

---
Regards,
WANG.Jiong