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Re: [drow@mvista.com: Re: _bfd_dwarf2_find_nearest_line returns wrong filename]
- From: Daniel Jacobowitz <drow at mvista dot com>
- To: binutils at sources dot redhat dot com
- Date: Tue, 25 Mar 2003 18:40:22 -0500
- Subject: Re: [drow@mvista.com: Re: _bfd_dwarf2_find_nearest_line returns wrong filename]
- References: <20030225045705.GA2837@nevyn.them.org>
Ping?
On Mon, Feb 24, 2003 at 11:57:05PM -0500, Daniel Jacobowitz wrote:
> This was buried in my discussion with Andreas; would someone mind
> reviewing the final patch?
>
> ----- Forwarded message from Daniel Jacobowitz <drow at mvista dot com> -----
>
> Date: Tue, 4 Feb 2003 10:37:05 -0500
> From: Daniel Jacobowitz <drow at mvista dot com>
> Subject: Re: _bfd_dwarf2_find_nearest_line returns wrong filename
> To: binutils at sources dot redhat dot com
> Mail-Followup-To: binutils at sources dot redhat dot com
>
> On Sun, Jan 19, 2003 at 06:00:21PM +0100, Andreas Schwab wrote:
> > Daniel Jacobowitz <drow at mvista dot com> writes:
> >
> > |> On Fri, Jan 03, 2003 at 03:39:40PM +0100, Andreas Schwab wrote:
> > |> > Daniel Jacobowitz <drow at mvista dot com> writes:
> > |> >
> > |> > |> No regressions, but some pertinent facts:
> > |> > |>
> > |> > |> - Examine the ld.log with this patch applied. Grep for BFD. You'll
> > |> > |> find several assertion failures indicating that the DWARF-2 data
> > |> > |> is incorrect. It's kind of sad that the testsuite doesn't notice any
> > |> > |> of these.
> > |> >
> > |> > I have now tried it on ia64, and it is getting worse. They are using
> > |> > R_IA64_SECREL32LS relocations in .debug_info, which is causing
> > |> > bfd_perform_relocation to return bfd_reloc_outofrange, and
> > |> > bfd_generic_get_relocated_section_contents is aborting on that.
> > |>
> > |> We needed to save and restore outputs in order to get the right answers
> > |> on i386 in some cases. We also needed some other fixes to ia64 - I
> > |> missed it when I swept the hash table create functions to make them use
> > |> bfd_malloc, I guess - and to weaken an abort in elfNN_ia64_reloc. But
> > |> now it works.
> >
> > This does not seem to work in the linker, it doesn't emit any filename
> > prefixes any more. This also causes testsuite failures, the ld-elfvsb
> > tests depend on the filename part of the error messages.
>
> I had the right idea, but I wasn't thorough enough implementing it. In
> addition to dummying the output offsets, we also have to dummy the
> output sections. Otherwise .debug_info thinks that a function starts
> up past 0x08400000, and the rest of the linker thinks that it starts at
> 0x18.
>
> Andreas, thanks for your continued patience. Would you mind testing
> this version?
>
> --
> Daniel Jacobowitz
> MontaVista Software Debian GNU/Linux Developer
>
> 2003-02-04 Andreas Schwab <schwab at suse dot de>
> Daniel Jacobowitz <drow at mvista dot com>
>
> * simple.c (bfd_simple_get_relocated_section_contents): Add
> parameter symbol_table. Optionally use it instead of the symbol
> table from the bfd. Save and restore output offsets and output
> sections around bfd_get_relocated_section_contents. Fix a memory
> leak.
> (simple_save_output_info, simple_restore_output_info): New
> functions.
> * bfd-in2.h: Regenerate.
> * dwarf2.c (read_abbrevs): Use
> bfd_simple_get_relocated_section_contents instead of
> bfd_get_section_contents.
> (decode_line_info): Likewise.
> (_bfd_dwarf2_find_nearest_line): Likewise. Don't call
> find_rela_addend.
> (find_rela_addend): Remove.
> * elfxx-ia64.c (elfNN_ia64_reloc): Weaken sanity check for
> debugging sections.
> (elfNN_ia64_hash_table_create): Create the hash table with malloc,
> not bfd_zalloc.
>
> Index: bfd/dwarf2.c
> ===================================================================
> RCS file: /big/fsf/rsync/src-cvs/src/bfd/dwarf2.c,v
> retrieving revision 1.42
> diff -u -p -r1.42 dwarf2.c
> --- bfd/dwarf2.c 12 Dec 2002 10:26:01 -0000 1.42
> +++ bfd/dwarf2.c 16 Jan 2003 20:52:45 -0000
> @@ -245,8 +245,6 @@ static bfd_boolean lookup_address_in_lin
> static bfd_boolean lookup_address_in_function_table
> PARAMS ((struct funcinfo *, bfd_vma, struct funcinfo **, const char **));
> static bfd_boolean scan_unit_for_functions PARAMS ((struct comp_unit *));
> -static bfd_vma find_rela_addend
> - PARAMS ((bfd *, asection *, bfd_size_type, asymbol**));
> static struct comp_unit *parse_comp_unit
> PARAMS ((bfd *, struct dwarf2_debug *, bfd_vma, unsigned int));
> static bfd_boolean comp_unit_contains_address
> @@ -546,13 +544,11 @@ read_abbrevs (abfd, offset, stash)
> }
>
> stash->dwarf_abbrev_size = msec->_raw_size;
> - stash->dwarf_abbrev_buffer = (char*) bfd_alloc (abfd, msec->_raw_size);
> + stash->dwarf_abbrev_buffer
> + = bfd_simple_get_relocated_section_contents (abfd, msec, NULL,
> + stash->syms);
> if (! stash->dwarf_abbrev_buffer)
> return 0;
> -
> - if (! bfd_get_section_contents (abfd, msec, stash->dwarf_abbrev_buffer,
> - (bfd_vma) 0, msec->_raw_size))
> - return 0;
> }
>
> if (offset >= stash->dwarf_abbrev_size)
> @@ -1019,21 +1015,15 @@ decode_line_info (unit, stash)
> }
>
> stash->dwarf_line_size = msec->_raw_size;
> - stash->dwarf_line_buffer = (char *) bfd_alloc (abfd, msec->_raw_size);
> + stash->dwarf_line_buffer
> + = bfd_simple_get_relocated_section_contents (abfd, msec, NULL,
> + stash->syms);
> if (! stash->dwarf_line_buffer)
> return 0;
> -
> - if (! bfd_get_section_contents (abfd, msec, stash->dwarf_line_buffer,
> - (bfd_vma) 0, msec->_raw_size))
> - return 0;
> -
> - /* FIXME: We ought to apply the relocs against this section before
> - we process it... */
> }
>
> - /* Since we are using un-relocated data, it is possible to get a bad value
> - for the line_offset. Validate it here so that we won't get a segfault
> - below. */
> + /* It is possible to get a bad value for the line_offset. Validate
> + it here so that we won't get a segfault below. */
> if (unit->line_offset >= stash->dwarf_line_size)
> {
> (*_bfd_error_handler) (_("Dwarf Error: Line offset (%lu) greater than or equal to .debug_line size (%lu)."),
> @@ -1521,60 +1511,6 @@ scan_unit_for_functions (unit)
> return TRUE;
> }
>
> -/* Look for a RELA relocation to be applied on OFFSET of section SEC,
> - and return the addend if such a relocation is found. Since this is
> - only used to find relocations referring to the .debug_abbrev
> - section, we make sure the relocation refers to this section, but
> - this is not strictly necessary, and it can probably be safely
> - removed if needed. However, it is important to note that this
> - function only returns the addend, it doesn't serve the purpose of
> - applying a generic relocation.
> -
> - If no suitable relocation is found, or if it is not a real RELA
> - relocation, this function returns 0. */
> -
> -static bfd_vma
> -find_rela_addend (abfd, sec, offset, syms)
> - bfd* abfd;
> - asection* sec;
> - bfd_size_type offset;
> - asymbol** syms;
> -{
> - long reloc_size = bfd_get_reloc_upper_bound (abfd, sec);
> - arelent **relocs = NULL;
> - long reloc_count, relc;
> -
> - if (reloc_size <= 0)
> - return 0;
> -
> - relocs = (arelent **) bfd_malloc ((bfd_size_type) reloc_size);
> - if (relocs == NULL)
> - return 0;
> -
> - reloc_count = bfd_canonicalize_reloc (abfd, sec, relocs, syms);
> -
> - if (reloc_count <= 0)
> - {
> - free (relocs);
> - return 0;
> - }
> -
> - for (relc = 0; relc < reloc_count; relc++)
> - if (relocs[relc]->address == offset
> - && (*relocs[relc]->sym_ptr_ptr)->flags & BSF_SECTION_SYM
> - && strcmp ((*relocs[relc]->sym_ptr_ptr)->name,
> - ".debug_abbrev") == 0)
> - {
> - bfd_vma addend = (relocs[relc]->howto->partial_inplace
> - ? 0 : relocs[relc]->addend);
> - free (relocs);
> - return addend;
> - }
> -
> - free (relocs);
> - return 0;
> -}
> -
> /* Parse a DWARF2 compilation unit starting at INFO_PTR. This
> includes the compilation unit header that proceeds the DIE's, but
> does not include the length field that preceeds each compilation
> @@ -1602,7 +1538,6 @@ parse_comp_unit (abfd, stash, unit_lengt
> char *info_ptr = stash->info_ptr;
> char *end_ptr = info_ptr + unit_length;
> bfd_size_type amt;
> - bfd_size_type off;
>
> version = read_2_bytes (abfd, info_ptr);
> info_ptr += 2;
> @@ -1611,12 +1546,6 @@ parse_comp_unit (abfd, stash, unit_lengt
> abbrev_offset = read_4_bytes (abfd, info_ptr);
> else
> abbrev_offset = read_8_bytes (abfd, info_ptr);
> - /* The abbrev offset is generally a relocation pointing to
> - .debug_abbrev+offset. On RELA targets, we have to find the
> - relocation and extract the addend to obtain the actual
> - abbrev_offset, so do it here. */
> - off = info_ptr - stash->sec_info_ptr;
> - abbrev_offset += find_rela_addend (abfd, stash->sec, off, stash->syms);
> info_ptr += offset_size;
> addr_size = read_1_byte (abfd, info_ptr);
> info_ptr += 1;
> @@ -1939,8 +1868,8 @@ _bfd_dwarf2_find_nearest_line (abfd, sec
>
> start = stash->info_ptr_end - stash->info_ptr;
>
> - if (! bfd_get_section_contents (abfd, msec, stash->info_ptr + start,
> - (bfd_vma) 0, size))
> + if ((bfd_simple_get_relocated_section_contents
> + (abfd, msec, stash->info_ptr + start, symbols)) == NULL)
> continue;
>
> stash->info_ptr_end = stash->info_ptr + start + size;
> @@ -1953,21 +1882,6 @@ _bfd_dwarf2_find_nearest_line (abfd, sec
> stash->syms = symbols;
> }
>
> - /* FIXME: There is a problem with the contents of the
> - .debug_info section. The 'low' and 'high' addresses of the
> - comp_units are computed by relocs against symbols in the
> - .text segment. We need these addresses in order to determine
> - the nearest line number, and so we have to resolve the
> - relocs. There is a similar problem when the .debug_line
> - section is processed as well (e.g., there may be relocs
> - against the operand of the DW_LNE_set_address operator).
> -
> - Unfortunately getting hold of the reloc information is hard...
> -
> - For now, this means that disassembling object files (as
> - opposed to fully executables) does not always work as well as
> - we would like. */
> -
> /* A null info_ptr indicates that there is no dwarf2 info
> (or that an error occured while setting up the stash). */
> if (! stash->info_ptr)
> @@ -2034,10 +1948,10 @@ _bfd_dwarf2_find_nearest_line (abfd, sec
> {
> if (comp_unit_contains_address (each, addr))
> return comp_unit_find_nearest_line (each, addr,
> - filename_ptr,
> - functionname_ptr,
> - linenumber_ptr,
> - stash);
> + filename_ptr,
> + functionname_ptr,
> + linenumber_ptr,
> + stash);
> }
> else
> {
> Index: bfd/elfxx-ia64.c
> ===================================================================
> RCS file: /big/fsf/rsync/src-cvs/src/bfd/elfxx-ia64.c,v
> retrieving revision 1.66
> diff -u -p -r1.66 elfxx-ia64.c
> --- bfd/elfxx-ia64.c 17 Jan 2003 23:27:55 -0000 1.66
> +++ bfd/elfxx-ia64.c 4 Feb 2003 15:31:06 -0000
> @@ -346,6 +346,10 @@ elfNN_ia64_reloc (abfd, reloc, sym, data
> reloc->address += input_section->output_offset;
> return bfd_reloc_ok;
> }
> +
> + if (input_section->flags & SEC_DEBUGGING)
> + return bfd_reloc_continue;
> +
> *error_message = "Unsupported call to elfNN_ia64_reloc";
> return bfd_reloc_notsupported;
> }
> @@ -1701,19 +1705,25 @@ elfNN_ia64_hash_table_create (abfd)
> {
> struct elfNN_ia64_link_hash_table *ret;
>
> - ret = bfd_zalloc (abfd, (bfd_size_type) sizeof (*ret));
> + ret = bfd_malloc ((bfd_size_type) sizeof (*ret));
> if (!ret)
> return 0;
> + memset (ret, 0, sizeof (*ret));
> +
> if (!_bfd_elf_link_hash_table_init (&ret->root, abfd,
> elfNN_ia64_new_elf_hash_entry))
> {
> - bfd_release (abfd, ret);
> + free (ret);
> return 0;
> }
>
> if (!elfNN_ia64_local_hash_table_init (&ret->loc_hash_table, abfd,
> elfNN_ia64_new_loc_hash_entry))
> - return 0;
> + {
> + free (ret);
> + return 0;
> + }
> +
> return &ret->root.root;
> }
>
> Index: bfd/simple.c
> ===================================================================
> RCS file: /big/fsf/rsync/src-cvs/src/bfd/simple.c,v
> retrieving revision 1.5
> diff -u -p -r1.5 simple.c
> --- bfd/simple.c 30 Nov 2002 08:39:40 -0000 1.5
> +++ bfd/simple.c 4 Feb 2003 15:28:20 -0000
> @@ -42,8 +42,14 @@ static bfd_boolean simple_dummy_reloc_da
> static bfd_boolean simple_dummy_unattached_reloc
> PARAMS ((struct bfd_link_info *, const char *, bfd *, asection *, bfd_vma));
>
> +static void simple_save_output_info
> + PARAMS ((bfd *, asection *, PTR));
> +
> +static void simple_restore_output_info
> + PARAMS ((bfd *, asection *, PTR));
> +
> bfd_byte * bfd_simple_get_relocated_section_contents
> - PARAMS ((bfd *, asection *, bfd_byte *));
> + PARAMS ((bfd *, asection *, bfd_byte *, asymbol **));
>
> static bfd_boolean
> simple_dummy_warning (link_info, warning, symbol, abfd, section, address)
> @@ -105,17 +111,48 @@ simple_dummy_unattached_reloc (link_info
> return TRUE;
> }
>
> +struct saved_output_info
> +{
> + bfd_vma offset;
> + asection *section;
> +};
> +
> +static void
> +simple_save_output_info (abfd, section, ptr)
> + bfd *abfd ATTRIBUTE_UNUSED;
> + asection *section;
> + PTR ptr;
> +{
> + struct saved_output_info *output_info = (struct saved_output_info *) ptr;
> + output_info[section->index].offset = section->output_offset;
> + output_info[section->index].section = section->output_section;
> + section->output_offset = 0;
> + section->output_section = section;
> +}
> +
> +static void
> +simple_restore_output_info (abfd, section, ptr)
> + bfd *abfd ATTRIBUTE_UNUSED;
> + asection *section;
> + PTR ptr;
> +{
> + struct saved_output_info *output_info = (struct saved_output_info *) ptr;
> + section->output_offset = output_info[section->index].offset;
> + section->output_section = output_info[section->index].section;
> +}
> +
> /*
> FUNCTION
> bfd_simple_relocate_secton
>
> SYNOPSIS
> - bfd_byte *bfd_simple_get_relocated_section_contents (bfd *abfd, asection *sec, bfd_byte *outbuf);
> + bfd_byte *bfd_simple_get_relocated_section_contents (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
>
> DESCRIPTION
> - Returns the relocated contents of section @var{sec}. Only symbols
> - from @var{abfd} and the output offsets assigned to sections in
> - @var{abfd} are used. The result will be stored at @var{outbuf}
> + Returns the relocated contents of section @var{sec}. The symbols in
> + @var{symbol_table} will be used, or the symbols from @var{abfd} if
> + @var{symbol_table} is NULL. The output offsets for all sections will
> + be temporarily reset to 0. The result will be stored at @var{outbuf}
> or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
>
> Generally all sections in @var{abfd} should have their
> @@ -126,17 +163,18 @@ DESCRIPTION
> */
>
> bfd_byte *
> -bfd_simple_get_relocated_section_contents (abfd, sec, outbuf)
> +bfd_simple_get_relocated_section_contents (abfd, sec, outbuf, symbol_table)
> bfd *abfd;
> asection *sec;
> bfd_byte *outbuf;
> + asymbol **symbol_table;
> {
> struct bfd_link_info link_info;
> struct bfd_link_order link_order;
> struct bfd_link_callbacks callbacks;
> bfd_byte *contents, *data;
> int storage_needed, number_of_symbols;
> - asymbol **symbol_table;
> + PTR saved_offsets;
>
> if (! (sec->flags & SEC_RELOC))
> {
> @@ -183,11 +221,36 @@ bfd_simple_get_relocated_section_content
> return NULL;
> outbuf = data;
> }
> - bfd_link_add_symbols (abfd, &link_info);
>
> - storage_needed = bfd_get_symtab_upper_bound (abfd);
> - symbol_table = (asymbol **) bfd_malloc (storage_needed);
> - number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
> + /* The sections in ABFD may already have output sections and offsets set.
> + Because this function is primarily for debug sections, and GCC uses the
> + knowledge that debug sections will generally have VMA 0 when emiting
> + relocations between DWARF-2 sections (which are supposed to be
> + section-relative offsets anyway), we need to reset the output offsets
> + to zero. We also need to arrange for section->output_section->vma plus
> + section->output_offset to equal section->vma, which we do by setting
> + section->output_section to point back to section. Save the original
> + output offset and output section to restore later. */
> + saved_offsets = malloc (sizeof (struct saved_output_info)
> + * abfd->section_count);
> + if (saved_offsets == NULL)
> + {
> + if (data)
> + free (data);
> + return NULL;
> + }
> + bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);
> +
> + if (symbol_table == NULL)
> + {
> + bfd_link_add_symbols (abfd, &link_info);
> +
> + storage_needed = bfd_get_symtab_upper_bound (abfd);
> + symbol_table = (asymbol **) bfd_malloc (storage_needed);
> + number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
> + }
> + else
> + storage_needed = 0;
>
> contents = bfd_get_relocated_section_contents (abfd,
> &link_info,
> @@ -197,6 +260,12 @@ bfd_simple_get_relocated_section_content
> symbol_table);
> if (contents == NULL && data != NULL)
> free (data);
> +
> + if (storage_needed != 0)
> + free (symbol_table);
> +
> + bfd_map_over_sections (abfd, simple_restore_output_info, saved_offsets);
> + free (saved_offsets);
>
> /* Foul hack to prevent bfd_section_size aborts. This flag only controls
> that macro (and the related size macros), selecting between _raw_size
>
>
> ----- End forwarded message -----
>
> --
> Daniel Jacobowitz
> MontaVista Software Debian GNU/Linux Developer
>
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer