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[RFA-v3] Fix PR 16201: internal error on a cygwin program linked against a DLL with no .data section
- From: "Pierre Muller" <pierre dot muller at ics-cnrs dot unistra dot fr>
- To: "'Pedro Alves'" <palves at redhat dot com>
- Cc: "'Joel Brobecker'" <brobecker at adacore dot com>, <gdb-patches at sourceware dot org>
- Date: Tue, 7 Jan 2014 12:15:00 +0100
- Subject: [RFA-v3] Fix PR 16201: internal error on a cygwin program linked against a DLL with no .data section
- Authentication-results: sourceware.org; auth=none
- References: <004801cef65e$cb82d1b0$62887510$ at muller@ics-cnrs.unistra.fr> <20131211170204 dot GD3227 at adacore dot com> <52ab7ec0 dot c8da420a dot 12c6 dot ffffb3f4SMTPIN_ADDED_BROKEN at mx dot google dot com> <52B48A28 dot 2000402 at redhat dot com> <52b76e14 dot 8886420a dot 29e6 dot ffffddb2SMTPIN_ADDED_BROKEN at mx dot google dot com> <52CAF71D dot 3050008 at redhat dot com>
> -----Message d'origine-----
> De : gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] De la part de Pedro Alves
> Envoyé : lundi 6 janvier 2014 19:34
> À : Pierre Muller
> Cc : 'Joel Brobecker'; gdb-patches@sourceware.org
> Objet : Re: [RFA-v2] Fix PR 16201: internal error on a cygwin program
> linked against a DLL with no .data section
>
> Hi Pierre,
>
> Sorry for the slow reply. Been away on vacation.
>
> On 12/22/2013 10:55 PM, Pierre Muller wrote:
> > @@ -455,17 +458,34 @@ read_pe_exported_syms (struct objfile *objfile)
> > unsigned long characteristics = pe_get32 (dll, secptr1 + 36);
> > char sec_name[SCNNMLEN + 1];
> > int sectix;
> > + unsigned int bfd_section_index;
> > + asection *section;
> >
> > bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET);
> > bfd_bread (sec_name, (bfd_size_type) SCNNMLEN, dll);
> > sec_name[SCNNMLEN] = '\0';
> >
> > sectix = read_pe_section_index (sec_name);
> > + section = bfd_get_section_by_name (dll, sec_name);
>
> Can't coff have sections with duplicate names?
I did not find anything in the PE COFF description
that explicitly said that each section should have a unique name
but I always assumed that the assembler/linker would
always group all sections with the same name.
Is there some object merge utility that could
group objects without merging?
> If so,
> then it'd be better to match the section some other way,
> I guess by address?
I would not know how to do this...
> > + if (section)
> > + bfd_section_index = section->index;
> > + else
> > + bfd_section_index = -1;
> >
> > if (sectix != PE_SECTION_INDEX_INVALID)
> > {
> > 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;
> > + section_data[sectix].index = bfd_section_index;
>
> Do you still need this part?
This is still an improvement as it sets
these sect_index_XXX fields that might be needed
elsewhere in the code.
Remember that the bug comes from the fact that those fields
were not set. However, I agree that the exact source
of the bug should be removed even without this part.
I would prefer to leave it inside this patch, as
it still reduces a potential problem elsewhere.
Here is an update, which also handles the forwarded
symbol by retrieving the section index of the minimal symbol.
Pierre Muller
2014-01-07 Pierre Muller <muller@sourceware.org>
Fix PR16201.
* coff-pe-read.c (struct read_pe_section_data): Add index field.
(add_pe_exported_sym): Use SECTION_DATA->INDEX for call
to prim_record_mininal_symbol_and_info.
(add_pe_forwarded_sym): Use known section number of forwarded symbol
in call to prim_record_minimal_symbol_and_info.
(read_pe_exported_syms): Set index field of section_data.
diff --git a/gdb/coff-pe-read.c b/gdb/coff-pe-read.c
index 749c109..01d6c69 100644
--- a/gdb/coff-pe-read.c
+++ b/gdb/coff-pe-read.c
@@ -53,6 +53,7 @@ struct read_pe_section_data
unsigned long rva_end; /* End offset within the pe. */
enum minimal_symbol_type ms_type; /* Type to assign symbols in
section. */
+ unsigned int index; /* Section number. */
char *section_name; /* Recorded section name. */
};
@@ -175,11 +176,13 @@ add_pe_exported_sym (const char *sym_name,
" for entry \"%s\" in dll \"%s\"\n"),
section_data->section_name, sym_name, dll_name);
- prim_record_minimal_symbol (qualified_name, vma,
- section_data->ms_type, objfile);
+ prim_record_minimal_symbol_and_info (qualified_name, vma,
+ section_data->ms_type,
+ section_data->index, objfile);
/* Enter the plain name as well, which might not be unique. */
- prim_record_minimal_symbol (bare_name, vma, section_data->ms_type,
objfile);
+ prim_record_minimal_symbol_and_info (bare_name, vma,
section_data->ms_type,
+ section_data->index, objfile);
if (debug_coff_pe_read > 1)
fprintf_unfiltered (gdb_stdlog, _("Adding exported symbol \"%s\""
" in dll \"%s\"\n"), sym_name, dll_name);
@@ -209,6 +212,7 @@ add_pe_forwarded_sym (const char *sym_name, const char
*forward_dll_name,
int forward_func_name_len = strlen (forward_func_name);
int forward_len = forward_dll_name_len + forward_func_name_len + 2;
char *forward_qualified_name = alloca (forward_len);
+ short section;
xsnprintf (forward_qualified_name, forward_len, "%s!%s",
forward_dll_name,
forward_func_name);
@@ -242,6 +246,7 @@ add_pe_forwarded_sym (const char *sym_name, const char
*forward_dll_name,
vma = SYMBOL_VALUE_ADDRESS (msymbol.minsym);
msymtype = MSYMBOL_TYPE (msymbol.minsym);
+ section = SYMBOL_SECTION (msymbol.minsym);
/* Generate a (hopefully unique) qualified name using the first part
of the dll name, e.g. KERNEL32!AddAtomA. This matches the style
@@ -254,10 +259,12 @@ add_pe_forwarded_sym (const char *sym_name, const char
*forward_dll_name,
qualified_name = xstrprintf ("%s!%s", dll_name, bare_name);
- prim_record_minimal_symbol (qualified_name, vma, msymtype, objfile);
+ prim_record_minimal_symbol_and_info (qualified_name, vma, msymtype,
+ section, objfile);
/* Enter the plain name as well, which might not be unique. */
- prim_record_minimal_symbol (bare_name, vma, msymtype, objfile);
+ prim_record_minimal_symbol_and_info (bare_name, vma, msymtype,
+ section, objfile);
xfree (qualified_name);
xfree (bare_name);
@@ -455,17 +462,34 @@ read_pe_exported_syms (struct objfile *objfile)
unsigned long characteristics = pe_get32 (dll, secptr1 + 36);
char sec_name[SCNNMLEN + 1];
int sectix;
+ unsigned int bfd_section_index;
+ asection *section;
bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET);
bfd_bread (sec_name, (bfd_size_type) SCNNMLEN, dll);
sec_name[SCNNMLEN] = '\0';
sectix = read_pe_section_index (sec_name);
+ section = bfd_get_section_by_name (dll, sec_name);
+ if (section)
+ bfd_section_index = section->index;
+ else
+ bfd_section_index = -1;
if (sectix != PE_SECTION_INDEX_INVALID)
{
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;
+ section_data[sectix].index = bfd_section_index;
}
else
{
@@ -479,6 +503,7 @@ read_pe_exported_syms (struct objfile *objfile)
section_data[otherix].rva_start = vaddr;
section_data[otherix].rva_end = vaddr + vsize;
section_data[otherix].vma_offset = 0;
+ section_data[otherix].index = bfd_section_index;
if (characteristics & IMAGE_SCN_CNT_CODE)
section_data[otherix].ms_type = mst_text;
else if (characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)