New in v2:
- Disable sharing only for -readnow objfiles, not all objfiles.
As described in PR 27541, we hit an internal error when loading a binary
the standard way and then loading it with the -readnow option:
$ ./gdb -nx -q --data-directory=data-directory ~/a.out -ex "set confirm off" -ex "file -readnow ~/a.out"
Reading symbols from /home/simark/a.out...
Reading symbols from ~/a.out...
/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8098: internal-error: void create_all_comp_units(dwarf2_per_objfile*): Assertion `per_objfile->per_bfd->all_comp_units.empty ()' failed.
This is a recurring problem that exposes a design issue in the DWARF
per-BFD sharing feature. Things work well when loading a binary with
the same method (with/without index, with/without readnow) twice in a
row. But they don't work so well when loading a binary with different
methods. See this previous fix, for example:
efb763a5ea35 ("gdb: check for partial symtab presence in dwarf2_initialize_objfile")
That one handled the case where the first load is normal (uses partial
symbols) and the second load uses an index.
The problem is that when loading an objfile with a method A, we create a
dwarf2_per_bfd and some dwarf2_per_cu_data and initialize them with the
data belonging to that method. When loading another obfile sharing the
same BFD but with a different method B, it's not clear how to re-use the
dwarf2_per_bfd/dwarf2_per_cu_data previously created, because they
contain the data specific to method A.
I think the most sensible fix would be to not share a dwarf2_per_bfd
between two objfiles loaded with different methods. That means that two
objfiles sharing the same BFD and loaded the same way would share a
dwarf2_per_bfd. Two objfiles sharing the same BFD but loaded with
different methods would use two different dwarf2_per_bfd structures.
However, this isn't a trivial change. So to fix the known issue quickly
(including in the gdb 10 branch), this patch just disables all
dwarf2_per_bfd sharing for objfiles using READNOW.
Generalize the gdb.base/index-cache-load-twice.exp test to test all
the possible combinations of loading a file with partial symtabs, index
and readnow. Move it to gdb.dwarf2, since it really exercises features
of the DWARF reader.
gdb/ChangeLog:
PR gdb/27541
* dwarf2/read.c (dwarf2_has_info): Don't share dwarf2_per_bfd
with objfiles using READNOW.
gdb/testsuite/ChangeLog:
PR gdb/27541
* gdb.base/index-cache-load-twice.exp: Remove.
* gdb.base/index-cache-load-twice.c: Remove.
* gdb.dwarf2/per-bfd-sharing.exp: New.
* gdb.dwarf2/per-bfd-sharing.c: New.
Change-Id: I9ffcf1e136f3e75242f70e4e58e4ba1fd3083389
Now that the quick functions are separate from the object file format,
there's no need to have elfread.c push a new entry on the objfile 'qf'
list. Instead, this detail can be pushed into the DWARF reader. That
is what this patch implements.
I wasn't sure whether lazy reading still makes sense or not. It's
still only used by ELF, and only in certain situations (like vfork, I
think). It may not be carrying its weight, so we may want to consider
removing this in the future.
Also, I'm unclear on why the various indices are only used for ELF.
This seems sub-optimal. However, I haven't tried to address that
here.
gdb/ChangeLog
2021-03-28 Tom Tromey <tom@tromey.com>
* elfread.c (can_lazily_read_symbols): Move to dwarf2/read.c.
(elf_symfile_read): Simplify.
* dwarf2/read.c (struct lazy_dwarf_reader): Move from elfread.c.
(make_lazy_dwarf_reader): New function.
(make_dwarf_gdb_index, make_dwarf_debug_names): Now static.
(dwarf2_initialize_objfile): Return void. Remove index_kind
parameter. Push on 'qf' list.
* dwarf2/public.h (dwarf2_initialize_objfile): Change return
type. Remove 'index_kind' parameter.
(make_dwarf_gdb_index, make_dwarf_debug_names): Don't declare.
This changes quick_symbol_functions::map_symbol_filenames to use a
function_view, and updates all the uses. It also changes the final
parameter to 'bool'. A couple of spots are further updated to use
operator() rather than a lambda.
gdb/ChangeLog
2021-03-26 Tom Tromey <tom@tromey.com>
* symtab.c (struct output_source_filename_data): Add 'output'
method and operator().
(output_source_filename_data::output): Rename from
output_source_filename.
(output_partial_symbol_filename): Remove.
(info_sources_command): Update.
(struct add_partial_filename_data): Add operator().
(add_partial_filename_data::operator()): Rename from
maybe_add_partial_symtab_filename.
(make_source_files_completion_list): Update.
* symfile.c (quick_symbol_functions): Update.
* symfile-debug.c (objfile::map_symbol_filenames): Update.
* quick-symbol.h (symbol_filename_ftype): Change type of 'fun' and
'need_fullname'. Remove 'data' parameter.
(struct quick_symbol_functions) <map_symbol_filenames>: Likewise.
* psymtab.c (psymbol_functions::map_symbol_filenames): Update.
* psympriv.h (struct psymbol_functions) <map_symbol_filenames>:
Change type of 'fun' and 'need_fullname'. Remove 'data'
parameter.
* objfiles.h (struct objfile) <map_symbol_filenames>: Change type
of 'fun' and 'need_fullname'. Remove 'data' parameter.
* mi/mi-cmd-file.c (print_partial_file_name): Remove 'ignore'
parameter.
(mi_cmd_file_list_exec_source_files): Update.
* dwarf2/read.c
(dwarf2_base_index_functions::map_symbol_filenames): Update.
I noticed a spot in the DWARF reader using "per_objfile->per_bfd",
where a local per_bfd variable had already been created. Looking
through the file, I found a number of such spots. This patch changes
them to use the already-existing local, avoiding a bit of excess
pointer chasing.
gdb/ChangeLog
2021-03-26 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_read_debug_names)
(dwarf2_build_psymtabs_hard, create_addrmap_from_aranges)
(dw2_debug_names_iterator::next, create_type_unit_group):
Simplify.
I noticed that dw2_map_matching_symbols does not use its 'kind'
parameter. This patch removes it. Tested by rebuilding.
2021-03-24 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dw2_map_matching_symbols): Update.
(dw2_expand_symtabs_matching_symbol): Remove 'kind' parameter.
(check_match, dw2_expand_symtabs_matching)
(dwarf2_debug_names_index::map_matching_symbols)
(dwarf2_debug_names_index::expand_symtabs_matching): Update.
Replace an abort call in process_psymtab_comp_unit with a real error,
and add a test to cover this case. The case is question is when badly
formed DWARF is missing a DW_TAG_compile_unit, DW_TAG_partial_unit, or
DW_TAG_type_unit as its top level tag.
I then tested with --target_board=readnow and added additional code to
also validate the top-level tag in this case.
I added an assert that would trigger for the readnow case before I
added the fix. I suspect there's lots of places where badly formed
DWARF could result in the builder being nullptr when it shouldn't be,
but I only added this one assert, as this is the one that would have
helped me in this case.
gdb/ChangeLog:
* dwarf2/read.c (process_psymtab_comp_unit): Replace abort with an
error.
(process_full_comp_unit): Validate the top-level tag before
processing the first DIE.
(read_func_scope): Ensure we have a valid builder.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-missing-cu-tag.c: New file.
* gdb.dwarf2/dw2-missing-cu-tag.exp: New file.
This changes objfile::qf to be a forward_list, and then updates all
the uses to iterate over the list. Note that there is still only ever
a single element in the list; this is handled by clearing the list
whenever an object is added.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_build_psymtabs): Update.
* symfile.c (syms_from_objfile_1, reread_symbols): Update.
* symfile-debug.c (objfile::has_partial_symbols)
(objfile::find_last_source_symtab)
(objfile::forget_cached_source_info)
(objfile::map_symtabs_matching_filename, objfile::lookup_symbol)
(objfile::print_stats, objfile::dump)
(objfile::expand_symtabs_for_function)
(objfile::expand_all_symtabs)
(objfile::expand_symtabs_with_fullname)
(objfile::map_matching_symbols)
(objfile::expand_symtabs_matching)
(objfile::find_pc_sect_compunit_symtab)
(objfile::map_symbol_filenames)
(objfile::find_compunit_symtab_by_address)
(objfile::lookup_global_symbol_language)
(objfile::require_partial_symbols): Update.
* psymtab.c (maintenance_print_psymbols)
(maintenance_info_psymtabs, maintenance_check_psymtabs): Update.
* objfiles.h (struct objfile) <qf>: Now a forward_list.
* objfiles.c (objfile_relocate1): Update.
* elfread.c (elf_symfile_read): Update.
Currently, the storage for partial symtabs is attached to the objfile.
Ultimately, though, this direct assocation will be removed, and the
storage will be owned by the psymbol_functions object.
This patch is a step toward this goal. The storage is already managed
as a shared_ptr, to enable cross-objfile sharing, so this adds a
reference from the psymbol_functions, and changes some code in
psymtab.c to use this reference instead.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_build_psymtabs): Call
set_partial_symtabs.
* symfile.c (syms_from_objfile_1, reread_symbols): Update.
* psymtab.h (make_psymbol_functions): Add partial_symtabs
parameter.
* psymtab.c (find_pc_sect_psymtab): Add partial_symtabs
parameter.
(psymbol_functions::find_pc_sect_compunit_symtab)
(psymbol_functions::print_stats, psymbol_functions::dump)
(psymbol_functions::has_symbols): Update.
(make_psymbol_functions, dump_psymtab_addrmap): Add
partial_symtabs parameter.
(maintenance_print_psymbols): Update.
(psymbol_functions::expand_symtabs_matching): Update.
* psympriv.h (struct psymbol_functions): Add constructor.
<m_partial_symtabs>: New member.
<set_partial_symtabs>: New method.
This changes the DWARF reader to reference the psymtabs via the
per_bfd object, rather than via the objfile. This helps isolate the
partial symtabs from the objfile.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_create_include_psymtab): Add per_bfd
parameter.
(process_psymtab_comp_unit_reader)
(build_type_psymtab_dependencies, dwarf2_build_psymtabs_hard)
(add_partial_subprogram, dwarf2_ranges_read, dwarf_decode_lines):
Reference psymtabs via per_bfd.
This changes the DWARF index writer to find the psymtab address map in
the per_bfd object, rather than go via the objfile.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/index-write.c (struct addrmap_index_data) <objfile>:
Remove.
(add_address_entry): Remove objfile parameter.
(add_address_entry_worker): Update.
(write_address_map): Replace objfile parameter with per_bfd.
(write_gdbindex, write_psymtabs_to_index): Update.
This moves all the psymtab statistics printing code form symmisc.c to
psymtab.c. This changes the formatting of the output a little, but
considering that it is a maint command (and, I assume, a rarely used
one), this seems fine to me.
This change helps further dissociate the psymtab from the objfile. In
the end there will be no direct connect -- only via the
quick_symbol_functions interface.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_base_index_functions::print_stats): Add
print_bcache parameter.
* symfile-debug.c (objfile::print_stats): Add print_bcache
parameter.
* quick-symbol.h (struct quick_symbol_functions)
<print_stats>: Add print_bcache parameter.
* symmisc.c (print_symbol_bcache_statistics, count_psyms): Move
code to psymtab.c.
(print_objfile_statistics): Move psymtab code to psymtab.c.
* psymtab.c (count_psyms): Move from symmisc.c.
(psymbol_functions::print_stats): Print partial symbol and bcache
statistics. Add print_bcache parameter.
* objfiles.h (print_symbol_bcache_statistics): Don't declare.
(struct objfile) <print_stats>: Add print_bcache parameter.
* maint.c (maintenance_print_statistics): Update.
gdb/testsuite/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* gdb.base/maint.exp: Update "maint print statistics" output.
Currently the DWARF index readers reuse the objfile's partial symbol
table in order to store an addrmap. We're going to be remove the
partial symbol object, so this patch changes the DWARF reader to store
this addrmap in the per_bfd object. This object is chosen, rather
than the quick_symbol_functions subclass, because the addrmap can be
shared across objfiles.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/read.h (struct dwarf2_per_bfd) <psymtabs_addrmap>: New
member.
* dwarf2/read.c (create_addrmap_from_index)
(create_addrmap_from_aranges): Set per_bfd addrmap.
(dwarf2_read_gdb_index): Don't set partial_symtabs.
(dwarf2_base_index_functions::find_pc_sect_compunit_symtab): Use
per_bfd addrmap.
(dwarf2_read_debug_names): Don't set partial_symtabs.
(dwarf2_initialize_objfile): Likewise.
dwarf2_build_psymtabs sets per_bfd->partial_symtabs at its end, in
order to facilitate sharing.
However, in order to diassociate partial symtabs from the objfile, we
want to change the DWARF reader to reference partial symtabs via the
per_bfd. So, we want to set this reference before reading psymtabs.
This is safe to do because the assignment is done unconditionally.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_build_psymtabs): Set partial_symtabs
earlier.
This changes the psymtab_discarder to not assume that partial symtabs
are attached to the objfile. Instead, a psymtab_storage object is
passed directly to it.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* psympriv.h (psymtab_discarder): Take psymtab_storage parameter.
(~psymtab_discarder, keep): Update.
<m_objfile>: Remove.
<m_partial_symtabs>: New member.
* dwarf2/read.c (dwarf2_build_psymtabs): Update.
This changes quick_symbol_functions to be a base class with pure
virtual methods, rather than a struct holding function pointers.
Then, objfile is changed to hold a unique_ptr to an instance of this
class.
struct psymbol_functions is put into psympriv.h, and not psymtab.c,
because that is convenient later in the series.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* psympriv.h (struct psymbol_functions): New.
* symfile.c (syms_from_objfile_1, reread_symbols): Update.
* symfile-debug.c (objfile::find_compunit_symtab_by_address)
(objfile::lookup_global_symbol_language): Update.
* quick-symbol.h (struct quick_symbol_functions): Convert function
pointers to methods. Add virtual destructor.
(quick_symbol_functions_up): New typedef.
* psymtab.h (psym_functions, dwarf2_gdb_index_functions)
(dwarf2_debug_names_functions): Don't declare.
(make_psymbol_functions): Declare.
* psymtab.c (psymbol_functions::map_symtabs_matching_filename)
(psymbol_functions::find_pc_sect_compunit_symtab)
(psymbol_functions::lookup_symbol)
(psymbol_functions::lookup_global_symbol_language)
(psymbol_functions::find_last_source_symtab)
(psymbol_functions::forget_cached_source_info)
(psymbol_functions::print_stats, psymbol_functions::dump)
(psymbol_functions::expand_symtabs_for_function)
(psymbol_functions::expand_all_symtabs)
(psymbol_functions::expand_symtabs_with_fullname)
(psymbol_functions::map_symbol_filenames)
(psymbol_functions::map_matching_symbols)
(psymbol_functions::expand_symtabs_matching)
(psymbol_functions::has_symbols)
(psymbol_functions::find_compunit_symtab_by_address): Rename.
(psym_functions): Remove.
(make_psymbol_functions): New function.
* objfiles.h (struct objfile) <qf>: Change type.
* elfread.c (elf_symfile_read): Update.
* dwarf2/read.c (struct dwarf2_base_index_functions)
(struct dwarf2_gdb_index, struct dwarf2_debug_names_index): New.
(make_dwarf_gdb_index, make_dwarf_debug_names): New functions.
(dwarf2_base_index_functions::find_last_source_symtab)
(dwarf2_base_index_functions::forget_cached_source_info)
(dwarf2_base_index_functions::map_symtabs_matching_filename)
(dwarf2_gdb_index::lookup_symbol)
(dwarf2_base_index_functions::print_stats)
(dwarf2_gdb_index::dump)
(dwarf2_gdb_index::expand_symtabs_for_function)
(dwarf2_base_index_functions::expand_all_symtabs)
(dwarf2_base_index_functions::expand_symtabs_with_fullname):
Rename.
(dwarf2_gdb_index::map_matching_symbols): New method.
(dwarf2_gdb_index::expand_symtabs_matching): New method.
(dwarf2_base_index_functions::find_pc_sect_compunit_symtab)
(dwarf2_base_index_functions::map_symbol_filenames)
(dwarf2_base_index_functions::has_symbols): Rename.
(dwarf2_gdb_index_functions): Remove.
(dwarf2_debug_names_index::lookup_symbol)
(dwarf2_debug_names_index::dump)
(dwarf2_debug_names_index::expand_symtabs_for_function)
(dwarf2_debug_names_index::map_matching_symbols)
(dwarf2_debug_names_index::expand_symtabs_matching): Rename.
(dwarf2_debug_names_functions): Remove.
* dwarf2/public.h (make_dwarf_gdb_index, make_dwarf_debug_names):
Declare.
This changes objfile_has_partial_symbols to be a method on objfile.
There are some other functions that could benefit from this sort of
change, but this was the only one that was relevant to this series.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* symfile.c (read_symbols): Update.
* objfiles.h (struct objfile) <has_partial_symbols>: New method.
(objfile_has_partial_symbols): Don't declare.
* objfiles.c (objfile::has_partial_symbols): Rename from
objfile_has_partial_symbols.
(objfile_has_symbols, have_partial_symbols): Update.
* elfread.c (elf_symfile_read): Update.
* dwarf2/read.c (dwarf2_has_info): Update.
* coffread.c (coff_symfile_read): Update.
This moves some more DWARF code out of symfile.h and into a new
header, dwarf2/public.h. This header is intended to describe the
public API of the DWARF reader.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* coffread.c: Include dwarf2/public.h.
* dwarf2/frame.c: Include dwarf2/public.h.
* dwarf2/index-write.h: Include dwarf2/public.h, not symfile.h.
* dwarf2/public.h: New file.
* dwarf2/read.c: Include dwarf2/public.h.
* elfread.c: Include dwarf2/public.h.
* machoread.c: Include dwarf2/public.h.
* symfile.h (dwarf2_has_info, enum dw_index_kind)
(dwarf2_initialize_objfile, dwarf2_build_psymtabs)
(dwarf2_build_frame_info): Move to dwarf2/public.h.
* xcoffread.c: Include dwarf2/public.h.
This moves a bit of the DWARF-specific code out of symfile.h and into
dwarf2/read.h.
gdb/ChangeLog
2021-03-20 Tom Tromey <tom@tromey.com>
* symfile.h (enum dwarf2_section_enum)
(dwarf2_get_section_info): Move to dwarf2/read.h.
* dwarf2/read.h (enum dwarf2_section_enum)
(dwarf2_get_section_info): Move from symfile.h.
I noticed that dwarf_unit_type_name is nearly identical to
get_DW_UT_name from libiberty; but rather than simply replacing it, it
seemed better to have it work like the other DWARF constant
stringification functions -- return a string showing unrecognized
numeric forms rather than nullptr. (The previous code did include
numeric values for the recognized constants, but this seems to be not
that useful to me.)
2021-03-18 Tom Tromey <tromey@adacore.com>
* dwarf2/stringify.c (dwarf_unit_type_name): New function. Use
get_DW_UT_name.
* dwarf2/stringify.h (dwarf_unit_type_name): Declare.
* dwarf2/comp-unit.c (dwarf_unit_type_name): Remove.
This printout in create_debug_type_hash_table has an unexpected colon at
the end, remove it:
[dwarf-read] create_debug_type_hash_table: Reading .debug_info for /home/simark/build/binutils-gdb/gdb/a.out:
gdb/ChangeLog:
* dwarf2/read.c (create_debug_type_hash_table): Remove colon at
end of debug print.
Change-Id: I2d707248249daf4d8b6fa8e7064acdc56c90f2dd
I added these printouts while working on 27541. I won't have a fix for
that right now, but I thought that it would be useful to merge them
upstream, as they help understand what happens in that function.
gdb/ChangeLog:
* dwarf2/read.c (dwarf2_initialize_objfile): Add debug prints.
Change-Id: I790c0d53383327038cb5dd705f74c8c978e0a7ec
I noticed that this parameter was unused, remove it.
gdb/ChangeLog:
* dwarf2/read.c (dw2_get_file_names_reader): Remove info_ptr
parameter, adjust caller.
Change-Id: I2a741766a0c658c22c512590aeffdd07391c869c
read_attribute_value has a local cu_header variable, but then some
spots in the function use cu->header instead. It seems better to me
to prefer the local everywhere, so this patch makes this change.
gdb/ChangeLog
2021-03-14 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (read_attribute_value): Use cu_header
consistently.
For an experiment I'm working on, it would be convenient if
die_reader_specs::cu could be NULL. This is fairly involved to
implement, but I did notice one spot that could conveniently be
updated. While making this trivial change, I also noticed a small,
related formatting error.
2021-03-14 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (struct die_reader_specs) <abfd>: Fix formatting.
(peek_die_abbrev): Use reader.abfd.
I noticed that nothing in dwarf2/read.c sets
dwarf2_per_cu_data::m_header_read_in. This patch adds the appropriate
assignment.
gdb/ChangeLog
2021-03-14 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_per_cu_data::get_header): Set
m_header_read_in.
This changes abbrev_table::lookup_abbrev to return a pointer to const,
then fixes up the affected code.
gdb/ChangeLog
2021-03-13 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (struct partial_die_info): Update.
(peek_die_abbrev, skip_children, skip_one_die, read_full_die_1)
(load_partial_dies, partial_die_info::partial_die_info): Update.
* dwarf2/abbrev.h (lookup_abbrev): Constify.
abbrev_table::read has a workaround for Irix 6. The last release of
Irix was in 2006, and (according to Wikipedia) hardware produced after
2007 cannot run Irix. I think this workaround can safely be retired.
gdb/ChangeLog
2021-03-13 Tom Tromey <tom@tromey.com>
* dwarf2/abbrev.c (abbrev_table::read): Remove Irix 6 workaround.
This moves dwarf2_get_dwz_file and some helper code to dwarf2/dwz.h.
The main benefit of this is just shrinking dwarf2/read.c a little bit.
gdb/ChangeLog
2021-03-06 Tom Tromey <tom@tromey.com>
* dwarf2/sect-names.h (dwarf2_elf_names): Declare.
* dwarf2/read.h (dwarf2_get_dwz_file): Move to dwz.h.
* dwarf2/read.c (dwarf2_elf_names): No longer static.
(locate_dwz_sections, dwz_search_other_debugdirs)
(dwarf2_get_dwz_file): Move to dwz.c.
* dwarf2/dwz.h (dwarf2_get_dwz_file): Move declaration from
read.h.
* dwarf2/dwz.c (locate_dwz_sections, dwz_search_other_debugdirs)
(dwarf2_get_dwz_file): Move from read.c.
If DWARF contains a reference to a "dwz" file, but there is no
.gnu_debugaltlink section, then gdb will crash. This happens because
dwarf2_get_dwz_file will return NULL, but some callers do not expect
this.
This patch changes dwarf2_get_dwz_file so that callers can require a
dwz file. Then, it updates the callers that are attempting to process
references to the dwz file to require one.
This includes a new testcase. The dwarf.exp changes don't handle the
new forms exactly correctly -- they are only handled well enough to
let this test case complete.
gdb/ChangeLog
2021-03-06 Tom Tromey <tom@tromey.com>
* dwarf2/read.h (dwarf2_get_dwz_file): Add 'require' parameter.
* dwarf2/read.c (dwarf2_get_dwz_file): Add 'require' parameter.
(get_abbrev_section_for_cu, read_attribute_value)
(get_debug_line_section): Update.
* dwarf2/macro.c (dwarf_decode_macro_bytes): Update.
gdb/testsuite/ChangeLog
2021-03-06 Tom Tromey <tom@tromey.com>
* lib/dwarf.exp (_handle_DW_FORM): Treat DW_FORM_GNU_ref_alt and
DW_FORM_GNU_strp_alt like DW_FORM_sec_offset.
* gdb.dwarf2/dwznolink.exp: New file.
This creates a new file, dwarf2/sect-names.h, and moves some
DWARF-specific type definitions from symfile.h into it.
gdb/ChangeLog
2021-03-06 Tom Tromey <tom@tromey.com>
* xcoffread.c: Include sect-names.h.
* symfile.h (struct dwarf2_section_names, struct
dwarf2_debug_sections): Move to dwarf2/sect-names.h.
* dwarf2/sect-names.h: New file, from symfile.h.
* dwarf2/read.c: Include sect-names.h.
Currently, and abbrev_info points to a separately allocated array of
attr_abbrev objects. This array is constructed in a temporary vector,
then copied to the abbrev table's obstack.
This patch changes abbrev_info to use the struct hack to store the
objects directly, and changes abbrev_table::read to avoid an extra
copy when allocating, using the "growing objects" capability of
obstacks.
This saves a bit of space, and also perhaps a little time.
2021-03-06 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (read_attribute): Make 'abbrev' const.
* dwarf2/abbrev.c (abbrev_table::alloc_abbrev): Remove.
(abbrev_table::read): Update.
* dwarf2/abbrev.h (struct attr_abbrev): Move earlier.
(struct abbrev_info): Reformat.
<attrs>: Now an array.
(struct abbrev_table) <alloc_abbrev>: Remove.
gdb currently supports two different styles of fixed-point. The
original style, where fixed point types are "GNAT encoded", is handled
primarily in the Ada code. The newer style, encoded using DWARF, is
handled by the core of gdb.
This patch changes gdb to read the GNAT encodings in the DWARF reader
as well. This removes some code and unifies the two paths. As a
result, GNAT-encoded fixed-point now works a bit better.
One possible drawback of this change is that, if someone uses stabs,
then fixed-point might now stop working. I consider stabs to be fully
obsolete, though, so I don't intend to address this.
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.c (cast_from_gnat_encoded_fixed_point_type)
(cast_to_gnat_encoded_fixed_point_type): Remove.
(ada_value_cast, ada_evaluate_subexp): Update.
(gnat_encoded_fixed_point_type_info)
(ada_is_gnat_encoded_fixed_point_type)
(gnat_encoded_fixed_point_delta)
(gnat_encoded_fixed_point_scaling_factor): Remove.
* ada-lang.h (ada_is_gnat_encoded_fixed_point_type)
(gnat_encoded_fixed_point_delta)
(gnat_encoded_fixed_point_scaling_factor): Don't declare.
* ada-typeprint.c (print_gnat_encoded_fixed_point_type): Remove.
(ada_print_type): Update.
* ada-valprint.c (ada_value_print_num): Update.
* dwarf2/read.c (ada_get_gnat_encoded_number)
(ada_get_gnat_encoded_ratio): New functions.
(finish_fixed_point_type): Use them. Add parameters.
(GNAT_FIXED_POINT_SUFFIX): New define.
(gnat_encoded_fixed_point_type_info): New function.
(read_base_type): Handle gnat encodings.
gdb/testsuite/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* gdb.ada/fixed_points.exp: Remove most special cases for minimal
encodings.
When running test-case gdb.dwarf2/fission-mix.exp using gcc-11 (and using the
tentative fix for PR27353 to get past that assertion failure), I run into:
...
(gdb) file fission-mix^M
Reading symbols from fission-mix...^M
Dwarf Error: wrong unit_type in compilation unit header \
(is DW_UT_split_compile (0x05), should be DW_UT_type (0x02)) \
[in module fission-mix2.dwo]^M
(No debugging symbols found in fission-mix)^M
...
The compilation unit that is complained about is:
...
Contents of the .debug_info.dwo section (loaded from fission-mix2.dwo):
Compilation Unit @ offset 0x0:
Length: 0x57 (32-bit)
Version: 5
Unit Type: DW_UT_split_compile (5)
Abbrev Offset: 0x0
Pointer Size: 8
DWO ID: 0x3e3930d3cc1805df
<0><14>: Abbrev Number: 1 (DW_TAG_compile_unit)
...
And the dwarf error is triggered here in read_comp_unit_head:
...
case DW_UT_split_compile:
if (section_kind != rcuh_kind::COMPILE)
error (_("Dwarf Error: wrong unit_type in compilation unit header "
"(is %s, should be %s) [in module %s]"),
dwarf_unit_type_name (cu_header->unit_type),
dwarf_unit_type_name (DW_UT_type), filename);
break;
...
due to passing rcuh_kind::TYPE here in open_and_init_dwo_file:
...
create_debug_type_hash_table (per_objfile, dwo_file.get (),
&dwo_file->sections.info, dwo_file->tus,
rcuh_kind::TYPE);
...
Fix this by changing the section_kind argument to create_debug_type_hash_table
to rcuh_kind::COMPILE, to reflect that we're passing &dwo_file->sections.info
rather than &dwo_file->sections.types.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-25 Tom de Vries <tdevries@suse.de>
PR symtab/27354
* dwarf2/read.c (open_and_init_dwo_file): Use rcuh_kind::COMPILE as
section_kind for &dwo_file->sections.info.
With test-case gdb.cp/temargs.exp on target board \
unix/gdb:debug_flags=-gdwarf-5 I run into:
...
(gdb) info addr I^M
ERROR: GDB process no longer exists
GDB process exited with wait status 32286 exp19 0 0 CHILDKILLED SIGABRT SIGABRT
UNRESOLVED: gdb.cp/temargs.exp: test address of I in templ_m
...
This is a regression since commit 529908cbd0a "Remove DW_UNSND".
The problem is that this DW_AT_decl_file:
...
<1><221>: Abbrev Number: 4 (DW_TAG_structure_type)
<222> DW_AT_name : Base<double, 23, (& a_global), &S::f>
<226> DW_AT_byte_size : 1
<226> DW_AT_decl_file : 1
<226> DW_AT_decl_line : 30
<227> DW_AT_sibling : <0x299>
...
is not read by this code in new_symbol:
....
attr = dwarf2_attr (die,
inlined_func ? DW_AT_call_file : DW_AT_decl_file,
cu);
if (attr != nullptr && attr->form_is_unsigned ())
...
because DW_AT_decl_file has form DW_FORM_implicit_const:
...
4 DW_TAG_structure_type [has children]
DW_AT_name DW_FORM_strp
DW_AT_byte_size DW_FORM_implicit_const: 1
DW_AT_decl_file DW_FORM_implicit_const: 1
DW_AT_decl_line DW_FORM_data1
DW_AT_sibling DW_FORM_ref4
DW_AT value: 0 DW_FORM value: 0
...
which is a signed LEB128, so attr->form_is_unsigned () returns false.
Fix this by introducing new functions is_nonnegative and as_nonnegative, and
use these instead of form_is_unsigned and as_unsigned.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-24 Tom de Vries <tdevries@suse.de>
PR symtab/27336
* dwarf2/attribute.c (attribute::form_is_signed): New function
factored out of ...
* dwarf2/attribute.h (attribute::as_signed): ... here.
(attribute::is_nonnegative, attribute::as_nonnegative): New function.
(attribute::form_is_signed): Declare.
* dwarf2/read.c (new_symbol): Use is_nonnegative and as_nonnegative
for DW_AT_decl_file.
As described in the log of patch "gdb/dwarf: add assertion in
maybe_queue_comp_unit", it would happen that a call to
maybe_queue_comp_unit would enqueue a CU in the to-expand queue while
nothing up the stack was processing the queue. This is not desirable,
as items are then left lingering in the queue when we exit the
dwarf2/read code. This is an inconsistent state.
The normal case of using the queue is when we go through
dw2_do_instantiate_symtab and process_queue. As depended-on CUs are
found, they get added to the queue. process_queue expands CUs until the
queue is empty.
To catch these cases where things are enqueued while nothing up the
stack is processing the queue, change dwarf2_per_bfd::queue to be an
optional. The optional is instantiated in dwarf2_queue_guard, just
before where we call process_queue. In the dwarf2_queue_guard
destructor, the optional gets reset. Therefore, the queue object is
instantiated only when something up the stack is handling it. If
another entry point tries to enqueue a CU for expansion, an assertion
will fail and we know we have something to fix.
dwarf2_queue_guard sounds like the good place for this, as it's
currently responsible for making sure the queue gets cleared if we exit
due to an error.
This also allows asserting that when age_comp_units or remove_all_cus
run, the queue is not instantiated, and gives us one more level of
assurance that we won't free the DIEs of a CU that is in the
CUs-to-expand queue.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (dwarf2_queue_guard) <dwarf2_queue_guard>:
Instantiate queue.
(~dwarf2_queue_guard): Clear queue.
(queue_comp_unit): Assert that queue is
instantiated.
(process_queue): Adjust.
* dwarf2/read.h (struct dwarf2_per_bfd) <queue>: Make optional.
Change-Id: I8fe3d77845bb4ad3d309eac906acebe79d9f0a9d
The previous commit log described how items could be left lingering in
the dwarf2_per_bfd::queue and how that could cause trouble.
This patch fixes the issue by changing maybe_queue_comp_unit so that it
doesn't put a CU in the to-expand queue if that CU is already expanded.
This will make it so that when dwarf2_fetch_die_type_sect_off calls
follow_die_offset and maybe_queue_comp_unit, it won't enqueue the target
CU, because it will see the CU is already expanded.
This assumes that if a CU is dwarf2_fetch_die_type_sect_off's target CU,
it will have previously been expanded. I think it is the case, but I
can't be 100% sure. If that's not true, the assertions added in the
following patch will catch it, and it means we'll have to re-think a bit
more how things work (it wouldn't be well handled at all today anyway).
This fixes something else in maybe_queue_comp_unit that looks wrong.
Imagine the DIEs of a CU are loaded in memory, but that CU is not
expanded. In that case, maybe_queue_comp_unit will use this early
return:
/* If the compilation unit is already loaded, just mark it as
used. */
dwarf2_cu *cu = per_objfile->get_cu (per_cu);
if (cu != nullptr)
{
cu->last_used = 0;
return 0;
}
... so the CU won't be queued for expansion. Whether the DIEs of a CU
are loaded in memory and whether that CU is expanded are two orthogonal
things, but that function appears to mix them. So, move the queuing
above that check / early return, so that if the CU's DIEs are loaded in
memory but the CU is not expanded yet, it gets enqueued.
I tried to improve maybe_queue_comp_unit's documentation to clarify what
the return value means. By clarifying this, I noticed that two callers
(follow_die_offset and follow_die_sig_1) access the CU's DIEs after
calling maybe_queue_comp_unit, only relying on maybe_queue_comp_unit's
return value to tell whether DIEs need to be loaded first or not. As
explained in the new comment, this is problematic:
maybe_queue_comp_unit's return value doesn't tell whether DIEs are
currently loaded, it means whether maybe_queue_comp_unit requires the
caller to load them. If the CU is already expanded but the DIEs to have
been freed, maybe_queue_comp_unit returns 0, meaning "I don't need you
to load the DIEs". So if these two functions (follow_die_offset and
follow_die_sig_1) need to access the DIEs in any case, for their own
usage, they should make sure to load them if they are not loaded
already. I therefore added an extra check to the condition they use,
making it so they will always load the DIEs if they aren't already.
From what I found, other callers don't care for the CU's DIEs, they call
maybe_queue_comp_unit to ensure the CU gets expanded eventually, but
don't care for it after that.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (maybe_queue_comp_unit): Check if CU is expanded
to decide whether or not to enqueue it for expansion.
(follow_die_offset, follow_die_sig_1): Ensure we load the DIEs
after calling maybe_queue_comp_unit.
Change-Id: Id98c6b60669f4b4b21b9be16d0518fc62bdf686a
When running test-case gdb.dwarf2/fission-mix.exp using gcc-11, I run into:
...
(gdb) file fission-mix^M
Reading symbols from fission-mix...^M
src/gdb/dwarf2/attribute.h:258: internal-error: \
void attribute::set_unsigned_reprocess(ULONGEST): \
Assertion `form_requires_reprocessing ()' failed.^M
...
This happens when calling set_unsigned_reprocess on an attribute with form
DW_FORM_strx. The assert triggers because DW_FORM_strx is not listed in
form_requires_reprocessing.
Fix this by adding DW_FORM_strx in form_requires_reprocessing.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-11 Tom de Vries <tdevries@suse.de>
PR symtab/27353
* dwarf2/attribute.c (attribute::form_requires_reprocessing):
Return true for DW_FORM_strx.
Delete two more symbol/section related macros. This time it's
SYMBOL_SECTION and MSYMBOL_SECTION.
As with general_symbol_info::m_name it is not currently possible to
make general_symbol_info::m_section private as general_symbol_info
must remain a POD type.
But other than failing to make the new m_section private, this change
does what you'd expect, adds a get and set member function and updates
all users to use the new functions instead of the previous wrapper
macros.
There should be no user visible change after this commit.
gdb/ChangeLog:
* coff-pe-read.c (add_pe_forwarded_sym): Make use of section_index
and set_section_index member functions where appropriate.
* coffread.c (coff_symtab_read): Likewise.
(process_coff_symbol): Likewise.
* ctfread.c (set_symbol_address): Likewise.
* dwarf2/read.c (add_partial_symbol): Likewise.
(var_decode_location): Likewise.
* language.c: Likewise.
* minsyms.c (minimal_symbol_reader::record_full): Likewise.
(compact_minimal_symbols): Likewise.
(minimal_symbol_upper_bound): Likewise.
* objfiles.c (relocate_one_symbol): Likewise.
* psympriv.h (partial_symbol::obj_section): Likewise.
(partial_symbol::address): Likewise.
* psymtab.c (partial_symtab::add_psymbol): Likewise.
* stabsread.c (scan_file_globals): Likewise.
* symmisc.c (dump_msymbols): Likewise.
* symtab.c (general_symbol_info::obj_section): Likewise.
(fixup_section): Likewise.
(get_msymbol_address): Likewise.
* symtab.h (general_symbol_info::section): Rename to...
(general_symbol_info::m_section): ...this.
(general_symbol_info::set_section_index): New member function.
(general_symbol_info::section_index): Likewise.
(SYMBOL_SECTION): Delete.
(MSYMBOL_VALUE_ADDRESS): Make use of section_index and
set_section_index member functions where appropriate.
(MSYMBOL_SECTION): Delete.
(symbol::symbol): Update to initialize 'm_section'.
* xcoffread.c (read_xcoff_symtab): Make use of set_section_index.
(process_xcoff_symbol): Likewise.
When running test-case gdb.fortran/function-calls.exp with target board
unix/gdb:debug_flags=-gdwarf-5, I run into:
...
(gdb) PASS: gdb.fortran/function-calls.exp: \
p derived_types_and_module_calls::pass_cart(c)
p derived_types_and_module_calls::pass_cart_nd(c_nd)^M
^M
Program received signal SIGSEGV, Segmentation fault.^M
0x0000000000400f73 in derived_types_and_module_calls::pass_cart_nd \
(c=<error reading variable: Cannot access memory at address 0xc>) at \
function-calls.f90:130^M
130 pass_cart_nd = ubound(c%d,1,4)^M
The program being debugged was signaled while in a function called from GDB.^M
GDB has restored the context to what it was before the call.^M
To change this behavior use "set unwindonsignal off".^M
Evaluation of the expression containing the function^M
(derived_types_and_module_calls::pass_cart_nd) will be abandoned.^M
(gdb) FAIL: gdb.fortran/function-calls.exp: p
...
The problem originates in read_array_type, when reading a DW_TAG_array_type
with a dwarf-5 DW_TAG_generic_subrange child. This is not supported, and the
fallout of this is that rather than constructing a new array type, the code
proceeds to modify the element type.
Fix this conservatively by issuing a complaint and bailing out in
read_array_type when not being able to construct an array type, such that we
have:
...
(gdb) maint expand-symtabs function-calls.f90^M
During symbol reading: unable to find array range \
- DIE at 0xe1e [in module function-calls]^M
During symbol reading: unable to find array range \
- DIE at 0xe1e [in module function-calls]^M
(gdb) KFAIL: gdb.fortran/function-calls.exp: no complaints in srcfile \
(PRMS: symtab/27388)
...
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-09 Tom de Vries <tdevries@suse.de>
PR symtab/27341
* dwarf2/read.c (read_array_type): Return NULL when not being able to
construct an array type. Add assert to ensure that element_type is
not being modified.
gdb/testsuite/ChangeLog:
2021-02-09 Tom de Vries <tdevries@suse.de>
PR symtab/27341
* lib/gdb.exp (with_complaints): New proc, factored out of ...
(gdb_load_no_complaints): ... here.
* gdb.fortran/function-calls.exp: Add test-case.
When running test-case gdb.cp/cpexprs-debug-types.exp with target board
unix/gdb:debug_flags=-gdwarf-5, I run into:
...
(gdb) file cpexprs-debug-types^M
Reading symbols from cpexprs-debug-types...^M
ERROR: Couldn't load cpexprs-debug-types into GDB (eof).
ERROR: Couldn't send delete breakpoints to GDB.
ERROR: GDB process no longer exists
GDB process exited with wait status 23054 exp9 0 0 CHILDKILLED SIGABRT SIGABRT
...
We're running into this abort in process_psymtab_comp_unit:
...
switch (reader.comp_unit_die->tag)
{
case DW_TAG_compile_unit:
this_cu->unit_type = DW_UT_compile;
break;
case DW_TAG_partial_unit:
this_cu->unit_type = DW_UT_partial;
break;
default:
abort ();
}
...
because reader.comp_unit_die->tag == DW_TAG_type_unit.
Fix this by adding a DW_TAG_type_unit case.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR symtab/27333
* dwarf2/read.c (process_psymtab_comp_unit): Handle DW_TAG_type_unit.
When running test-case gdb.dwarf2/clang-debug-names.exp, I run into the
following warning:
...
(gdb) file clang-debug-names^M
Reading symbols from clang-debug-names...^M
warning: Section .debug_aranges in clang-debug-names has duplicate \
debug_info_offset 0xc7, ignoring .debug_aranges.^M
...
This is caused by a missing return in commit 3ee6bb113af "[gdb/symtab] Fix
incomplete CU list assert in .debug_names".
Fix this by adding the missing return, such that we have instead this warning:
...
(gdb) file clang-debug-names^M
Reading symbols from clang-debug-names...^M
warning: Section .debug_aranges in clang-debug-names \
entry at offset 0 debug_info_offset 0 does not exists, \
ignoring .debug_aranges.^M
...
which is a known problem filed as PR25969 - "Ignoring .debug_aranges with
clang .debug_names".
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR symtab/27307
* dwarf2/read.c (create_cus_from_debug_names_list): Add missing
return.
gdb/testsuite/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR symtab/27307
* gdb.dwarf2/clang-debug-names.exp: Check file command warnings.
Fix indentation in !map.augmentation_is_gdb part of
create_cus_from_debug_names_list.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
* dwarf2/read.c (create_cus_from_debug_names_list): Fix indentation.
I think it's wrong that read_loclist_index and read_rnglist_index return
a CORE_ADDR. A CORE_ADDR is an address in the program. These functions
return offset in sections (.debug_loclists and .debug_rnglists). I
think sect_offset is more appropriate.
I'm wondering if struct attribute should have a "set_sect_offset"
method, that takes a sect_offset parameter, or if it's better to be
left as a simple "unsigned".
gdb/ChangeLog:
* dwarf2/read.c (read_loclist_index, read_rnglist_index): Return
a sect_offset.
(read_attribute_reprocess): Adjust.
Change-Id: I0e22e0864130fb490072b41ae099762918b8ad4d
Consider the test case added in this patch. It defines a compilation
unit with a DW_AT_rnglists_base attribute (used for attributes of form
DW_FORM_rnglistx), but also uses DW_AT_ranges of form
DW_FORM_sec_offset:
0x00000027: DW_TAG_compile_unit
DW_AT_ranges [DW_FORM_sec_offset] (0x0000004c
[0x0000000000005000, 0x0000000000006000))
DW_AT_rnglists_base [DW_FORM_sec_offset] (0x00000044)
The DW_AT_rnglists_base does not play a role in reading the DW_AT_ranges of
form DW_FORM_sec_offset, but it should also not do any harm.
This case is currently not handled correctly by GDB. This is not
something that a compiler is likely to emit, but in my opinion there's
no reason why GDB should fail reading it.
The problem is that in partial_die_info::read and a few other places
where the same logic is replicated, the cu->ranges_base value,
containing the DW_AT_rnglists_base value, is wrongfully added to the
DW_AT_ranges value.
It is quite messy how to decide whether cu->ranges_base should be added
to the attribute's value or not. But to summarize, the only time we
want to add it is when the attribute comes from a pre-DWARF 5 split unit
file (a .dwo) [1]. In this case, the DW_AT_ranges attribute from the
split unit file will have form DW_FORM_sec_offset, pointing somewhere in
the linked file's .debug_ranges section. *But* it's not a "true"
DW_FORM_sec_offset, in that it's an offset relative to the beginning of
that CU's contribution in the section, not relative to the beginning of
the section. So in that case, and only that case, do we want to add the
ranges base value, which we found from the DW_AT_GNU_ranges_base
attribute on the skeleton unit.
Almost all instances of the DW_AT_ranges attribute will be found in the
split unit (on DW_TAG_subprogram, for example), and therefore need to
have the ranges base added. However, the DW_TAG_compile_unit DIE in the
skeleton may also have a DW_AT_ranges attribute. For that one, the
ranges base must not be added. Once the DIEs have been loaded in GDB,
however, the distinction between what's coming from the skeleton and
what's coming from the split unit is not clear. It is all merged in one
big happy tree. So how do we know if a given attribute comes from the
split unit or not?
We use the fact that in pre-DWARF 5 split DWARF, DW_AT_ranges is found
on the skeleton's DW_TAG_compile_unit (in the linked file) and never in
the split unit's DW_TAG_compile_unit. This is why you have this in
partial_die_info::read:
int need_ranges_base = (tag != DW_TAG_compile_unit
&& attr.form != DW_FORM_rnglistx);
However, with the corner case described above (where we have a
DW_AT_rnglists_base attribute and a DW_AT_ranges attribute of form
DW_FORM_sec_offset) the condition gets it wrong when it encounters an
attribute like DW_TAG_subprogram with a DW_AT_ranges attribute of
DW_FORM_sec_offset form: it thinks that it is necessary to add the base,
when it reality it is not.
The problem boils down to failing to differentiate these cases:
- a DW_AT_ranges attribute of form DW_FORM_sec_offset in a
pre-DWARF 5 split unit (in which case we need to add the base)
- a DW_AT_ranges attribute of form DW_FORM_sec_offset in a DWARF 5
non-split unit (in which case we must not add the base)
What makes it unnecessarily complex is that the cu->ranges_base field is
overloaded, used to hold the pre-DWARF 5, non-standard
DW_AT_GNU_ranges_base and the DWARF 5 DW_AT_rnglists_base. In reality,
these two are called "bases" but are not the same thing. The result is
that we need twisted conditions to try to determine whether or not we
should add the base to the attribute's value.
To fix it, split the field in two distinct fields. I renamed everything
related to the "old" ranges base to "gnu_ranges_base", to make it clear
that it's about the non-standard, pre-DWARF 5 thing. And everything
related to the DWARF 5 thing gets renamed "rnglists". I think it
becomes much easier to reason this way.
The issue described above gets fixed by the fact that the
DW_AT_rnglists_base value does not end up in cu->gnu_ranges_base, so
cu->gnu_ranges_base stays 0. The condition to determine whether
gnu_ranges_base should be added can therefore be simplified back to:
tag != DW_TAG_compile_unit
... as it was before rnglistx support was added.
Extend the gdb.dwarf2/rnglists-sec-offset.exp to cover this case. I
also extended the test case for loclists similarly, just to see if there
would be some similar problem. There wasn't, but I think it's not a bad
idea to test that case for loclists as well, so I left it in the patch.
[1] https://gcc.gnu.org/wiki/DebugFission
gdb/ChangeLog:
* dwarf2/die.h (struct die_info) <ranges_base>: Split in...
<gnu_ranges_base>: ... this...
<rnglists_base>: ... and this.
* dwarf2/read.c (struct dwarf2_cu) <ranges_base>: Split in...
<gnu_ranges_base>: ... this...
<rnglists_base>: ... and this.
(read_cutu_die_from_dwo): Adjust
(dwarf2_get_pc_bounds): Adjust
(dwarf2_record_block_ranges): Adjust.
(read_full_die_1): Adjust
(partial_die_info::read): Adjust.
(read_rnglist_index): Adjust.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/rnglists-sec-offset.exp: Add test for DW_AT_ranges
of DW_FORM_sec_offset form plus DW_AT_rnglists_base attribute.
* gdb.dwarf2/loclists-sec-offset.exp: Add test for
DW_AT_location of DW_FORM_sec_offset plus DW_AT_loclists_base
attribute
Change-Id: Icd109038634b75d0e6e9d7d1dcb62fb9eb951d83
When loading the binary from PR 26813 in GDB, we get:
DW_FORM_rnglistx index pointing outside of .debug_rnglists offset array [in module /home/simark/build/binutils-gdb/gdb/MagicPurse]
... and the symbols fail to load.
In read_rnglist_index and read_loclist_index, we read the header
(documented in sections 7.28 and 7.29 of DWARF 5) of the CU's
contribution to the .debug_rnglists / .debug_loclists sections to
validate that the index we want to read makes sense. However, we always
read the header at the beginning of the section, rather than the header
for the contribution from which we want to read the index.
To illustrate, here's what the binary from PR 26813 contains. There are
two compile units:
0x0000000c: DW_TAG_compile_unit 1
DW_AT_ranges [DW_FORM_rnglistx]: 0x0
DW_AT_rnglists_base [DW_FORM_sec_offset]: 0xC
0x00003ec9: DW_TAG_compile_unit 2
DW_AT_ranges [DW_FORM_rnglistx]: 0xB
DW_AT_rnglists_base [DW_FORM_sec_offset]: 0x85
The layout of the .debug_rnglists is the following:
[0x00, 0x0B]: header for CU 1's contribution
[0x0C, 0x0F]: list of offsets for CU 1 (1 element)
[0x10, 0x78]: range lists data for CU 1
[0x79, 0x84]: header for CU 2's contribution
[0x85, 0xB4]: list of offsets for CU 2 (12 elements)
[0xB5, 0xBD7]: range lists data for CU 2
The DW_AT_rnglists_base attrbute points to the beginning of the list of
offsets for that CU, relative to the start of the .debug_rnglists
section. That's right after the header for that contribution.
When we try to read the DW_AT_ranges attribute for CU 2,
read_rnglist_index reads the header for CU 1 instead of the one for CU
2. Since there's only one element in CU 1's offset list, it believes
(wrongfully) that the index 0xB is out of range.
Fix it by reading the header just before where DW_AT_rnglists_base
points to. With this patch, I am able to load GDB built with clang-11
and -gdwarf-5 in itself, with and without -readnow.
gdb/ChangeLog:
PR gdb/26813
* dwarf2/read.c (read_loclists_rnglists_header): Add
header_offset parameter and use it.
(read_loclist_index): Read header of the current contribution,
not the one at the beginning of the section.
(read_rnglist_index): Likewise.
Change-Id: Ie53ff8251af8c1556f0a83a31aa8572044b79e3d
We hit an assertion when loading the binary from PR 26813. When fixing
it, execution goes a up bit further but then hits another assert, and
another, and another. With these fours fixes, I am able to load the
binary and get to the prompt. An error is shown (index pointing outside
of the section), because the DW_FORM_rnglistx attribute is not read
correctly, but that one is taken care of by the next patch.
The four fixes are:
- attribute::form_requires_reprocessing needs to handle forms
DW_FORM_rnglistx and DW_FORM_loclistx, because set_unsigned_reprocess
is called for them in read_attribute_value.
- read_attribute_reprocess must call set_unsigned for them, not
set_address. The parameter of set_address is a CORE_ADDR, meaning
it's for program addresses. Post-reprocess, DW_FORM_rnglistx and
DW_FORM_loclistx are offsets into their respective sections
(.debug_rnglists and .debug_loclists). set_unsigned is the current
attribute value setter that fits the best. But perhaps we should have
a setter that takes a sect_offset?
- read_attribute_process must call as_unsigned_reprocess instead of
as_unsigned to get the pre-reprocess value, otherwise we hit the
assert inside as_unsigned that makes sure the attribute doesn't need
reprocessing.
- attribute::set_unsigned needs to clear the requires_reprocessing flag,
otherwise it stays set when reprocessing DW_FORM_rnglistx and
DW_FORM_loclistx attributes.
There's another assert that we hit once the next patch is applied, but
since it's in the same vein as the changes in this patch, I included it
in this patch:
- attribute::form_is_unsigned must handle form DW_FORM_loclistx,
otherwise we hit the assert when trying to call set_unsigned for an
attribute of this form. DW_FORM_rnglistx is already handled.
gdb/ChangeLog:
PR gdb/26813
* dwarf2/attribute.h (struct attribute) <set_unsigned>: Clear
requires_reprocessing flag.
* dwarf2/attribute.c (attribute::form_is_unsigned): Handle
DW_FORM_loclistx.
(attribute::form_requires_reprocessing): Handle DW_FORM_rnglistx
and DW_FORM_loclistx.
* dwarf2/read.c (read_attribute_reprocess): Use set_unsigned
instead of set_address for DW_FORM_loclistx and
DW_FORM_rnglistx.
Change-Id: I06c156fa3913ca98e4e39085f4ef171645b4bc1e
