[RFA-v2] Fix PR 16201: internal error on a cygwin program linked against a DLL with no .data section

["Pierre Muller" <pierre.muller@ics-cnrs.unistra.fr>]

> -----Message d'origine-----
> De : gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] De la part de Joel Brobecker
> Envoyé : mercredi 11 décembre 2013 18:02
> À : Pierre Muller
> Cc : gdb-patches@sourceware.org
> Objet : Re: [PING RFA] Fix PR 16201: internal error on a cygwin program
> linked against a DLL with no .data section
> 
> > and an answer from Joel stating that he would prefer
> > that someone else with more knowledge about objfile struct
> > would review my RFA...
> > https://sourceware.org/ml/gdb-patches/2013-12/msg00036.html
> >
> > We got no other reaction yet.
> >
> > Should I press Joel to review it nonetheless
> > or does someone else volunteer to review this patch?
> 
> I just re-read the code, and I really think it would be better if
> someone who actually understands the general framework could comment.
> The problem seems, as you stated, relatively well understood, but
> I am not sure how we are expected to fix it.
> 
> > 2013-11-27  Pierre Muller  <muller@sourceware.org>
> >
> >         PR 16201
> >         coff-pe-read.c (read_pe_exported_syms): Set sect_index_text,
> >         sect_index_data and sect_index_bss of objfile struct, even if
> >         there is no canonical '.text', '.data' or '.bss' named
> section.
> 
> My only comment is that the patch could gain from some additional
> comments explaining _why_ you're forcing the sect_index field
> ("event if already set before"), and what you are trying to achieve.

Here is a new version in which I try to explain
more clearly that if we find the canonical
 '.text', '.data' or '.bss' section names,
we should use these sections to set sect_index_XXX.
Otherwise, we use the first section that is used later with
for which we set ms_type to mst_XXX to also set sect_index_XXX.
  This ensure that sect_index_XXX is always set if
any exported symbol is in inserted using
prim_rcord_minimal_symbol with ms_type parameter set to mst_XXX

I hope this clarifies the patch .

  
Pierre




ChangeLog entry:

2013-12-13  Pierre Muller  <muller@sourceware.org>

        Fix PR16201.
        coff-pe-read.c (read_pe_exported_syms): Set OBJFILE->sect_index_XXX
        for XXX text, data or bss to any section that sets ms_type
        field of section_data to mst_XXX, with preference
        to canonical names '.text', '.data' and '.bss'.

 
diff --git a/gdb/coff-pe-read.c b/gdb/coff-pe-read.c
index 91ee3f6..ec9aed5 100644
--- a/gdb/coff-pe-read.c
+++ b/gdb/coff-pe-read.c
@@ -466,6 +466,15 @@ read_pe_exported_syms (struct objfile *objfile)
        {
          section_data[sectix].rva_start = vaddr;
          section_data[sectix].rva_end = vaddr + vsize;
+         /* For .text, .data and .bss section
+             set corresponding sect_index_XXX,
+             even if it was already set before.  */
+         if (sectix == PE_SECTION_INDEX_TEXT)
+           objfile->sect_index_text = sectix;
+         if (sectix == PE_SECTION_INDEX_DATA)
+           objfile->sect_index_data = sectix;
+         if (sectix == PE_SECTION_INDEX_BSS)
+           objfile->sect_index_bss = sectix;
        }
       else
        {
@@ -480,11 +489,23 @@ read_pe_exported_syms (struct objfile *objfile)
          section_data[otherix].rva_end = vaddr + vsize;
          section_data[otherix].vma_offset = 0;
          if (characteristics & IMAGE_SCN_CNT_CODE)
-           section_data[otherix].ms_type = mst_text;
+           {
+             section_data[otherix].ms_type = mst_text;
+             if (objfile->sect_index_text == -1)
+               objfile->sect_index_text = otherix;
+           }
          else if (characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)
-           section_data[otherix].ms_type = mst_data;
+           {
+             section_data[otherix].ms_type = mst_data;
+             if (objfile->sect_index_data == -1)
+             objfile->sect_index_data = otherix;
+           }
          else if (characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
-           section_data[otherix].ms_type = mst_bss;
+           {
+             section_data[otherix].ms_type = mst_bss;
+             if (objfile->sect_index_bss == -1)
+               objfile->sect_index_bss = otherix;
+           }
          else
            section_data[otherix].ms_type = mst_unknown;
          otherix++;