With the test-case attached in PR26327, gdb aborts:
...
$ gdb -q -batch 447.dealII -ex "b main"
Aborted (core dumped)
...
when running out of stack due to infinite recursion:
...
#8 0x00000000006aaba6 in dwarf2_cu::get_builder (this=0x35e4b40)
at src/gdb/dwarf2/read.c:700
#9 0x00000000006aaba6 in dwarf2_cu::get_builder (this=0x22ee2c0)
at src/gdb/dwarf2/read.c:700
#10 0x00000000006aaba6 in dwarf2_cu::get_builder (this=0x35e4b40)
at src/gdb/dwarf2/read.c:700
#11 0x00000000006aaba6 in dwarf2_cu::get_builder (this=0x22ee2c0)
at src/gdb/dwarf2/read.c:700
...
We're recursing in this code in dwarf2_cu::get_builder():
...
/* Otherwise, search ancestors for a valid builder. */
if (ancestor != nullptr)
return ancestor->get_builder ();
...
due to the fact that the ancestor chain is a cycle.
Higher up in the call stack, we find some code that is responsible for
triggering this, in new_symbol:
...
case DW_TAG_formal_parameter:
{
/* If we are inside a function, mark this as an argument. If
not, we might be looking at an argument to an inlined function
when we do not have enough information to show inlined frames;
pretend it's a local variable in that case so that the user can
still see it. */
struct context_stack *curr
= cu->get_builder ()->get_current_context_stack ();
if (curr != nullptr && curr->name != nullptr)
SYMBOL_IS_ARGUMENT (sym) = 1;
...
This is code that was added to support pre-4.1 gcc, to be able to show
arguments of inlined functions as locals, in the absense of sufficiently
correct debug information.
Removing this code (that is, doing SYMBOL_IS_ARGUMENT (sym) = 1
unconditially), fixes the crash. The ancestor variable also seems to have
been added specifically to deal with fallout from this code, so remove that as
well.
Tested on x86_64-linux:
- openSUSE Leap 15.2 with gcc 7.5.0, and
- openSUSE Tumbleweed with gcc 10.3.0.
gdb/ChangeLog:
2021-05-07 Tom de Vries <tdevries@suse.de>
PR symtab/26327
* dwarf2/read.c (struct dwarf2_cu): Remove ancestor.
(dwarf2_cu::get_builder): Remove ancestor-related code.
(new_symbol): Remove code supporting pre-4.1 gcc that show arguments
of inlined functions as locals.
(follow_die_offset, follow_die_sig_1): Remove setting of ancestor.
gdb/doc/ChangeLog:
2021-05-07 Tom de Vries <tdevries@suse.de>
PR symtab/26327
* gdb.texinfo (Inline Functions): Update.
Currently, the DWARF reader has a separate pass to read type units --
create_all_type_units. While working on other patches, I discovered
that this caused DWARF 5 type units to be read twice, once by
create_all_comp_units and once by create_all_type_units.
There's no need any more (if there ever was) to treat type units
differently from CUs. So, this patch removes create_all_type_units
and unifies the code paths.
Note that the DWO code still has a second pass. I haven't looked into
this code yet; perhaps it can also be simplified.
Regression tested using the debug-types board file on x86-64 Fedora 32.
gdb/ChangeLog
2021-04-30 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_initialize_objfile): Update.
(add_signatured_type_cu_to_table): Remove.
(create_debug_type_hash_table): Assume dwo_file is non-null.
(create_debug_types_hash_table): Update comment.
(create_all_type_units): Remove.
(sort_tu_by_abbrev_offset): Update comment.
(build_type_psymtabs): Rename from build_type_psymtabs_1.
(build_type_psymtabs): Remove.
(process_skeletonless_type_unit, dwarf2_build_psymtabs_hard):
Update.
(read_comp_units_from_section): Add types_htab, section_kind
parameters.
(create_all_comp_units): Read type units.
I don't think there is any deep reason to separate CUs and TUs in
dwarf2_per_bfd. This patch removes all_type_units and unifies these
two containers. Some minor tweaks are needed to the index writers,
because both forms of index keep CUs and TUs separate;
Regression tested on x86-63 Fedora 32.
gdb/ChangeLog
2021-04-30 Tom Tromey <tom@tromey.com>
* dwarf2/read.h (struct tu_stats) <nr_tus>: New member.
(struct dwarf2_per_bfd) <get_cutu, get_tu>: Remove
<get_cu>: Now inline.
<all_type_units>: Remove.
* dwarf2/read.c (dwarf2_per_bfd::~dwarf2_per_bfd): Update.
(dwarf2_per_bfd::get_cutu, dwarf2_per_bfd::get_cu)
(dwarf2_per_bfd::get_tu): Remove.
(dwarf2_per_bfd::allocate_signatured_type): Update nr_tus.
(create_signatured_type_table_from_index)
(create_signatured_type_table_from_debug_names)
(dw2_symtab_iter_next, dwarf2_base_index_functions::print_stats)
(dwarf2_base_index_functions::expand_all_symtabs)
(dw2_expand_marked_cus, dw_expand_symtabs_matching_file_matcher)
(dwarf2_base_index_functions::map_symbol_filenames)
(dw2_debug_names_iterator::next, dwarf2_initialize_objfile)
(add_signatured_type_cu_to_table, create_all_type_units)
(add_type_unit, build_type_psymtabs_1, print_tu_stats)
(create_all_comp_units): Update.
* dwarf2/index-write.c (check_dwarf64_offsets, write_gdbindex)
(write_debug_names): Update.
In a patch series I am working on, I'd like to have a non-POD member
in dwarf2_per_cu_data. This currently can't be done because
dwarf2_per_cu_data is allocated on an obstack and initialized with
memset.
This patch changes the DWARF reader to allocate objects of this type
with 'new'. The various "subclasses" of this type (signatured_type in
particular) are now changed to derive from dwarf2_per_cu_data, and
also use 'new' for allocation.
Regression tested on x86-64 Fedora 32.
gdb/ChangeLog
2021-04-30 Tom Tromey <tom@tromey.com>
* dwarf2/read.h (struct dwarf2_per_bfd) <allocate_per_cu,
allocate_signatured_type>: Change return type.
<all_comp_units, all_type_units>: Hold unique pointers.
(struct dwarf2_per_cu_data): Add constructor and initializers.
(struct signatured_type): Derive from dwarf2_per_cu_data.
* dwarf2/read.c (type_unit_group): Derive from
dwarf2_per_cu_data.
(dwarf2_per_bfd::get_cutu, dwarf2_per_bfd::get_cu)
(dwarf2_per_bfd::get_tu)
(dwarf2_per_bfd::allocate_signatured_type)
(dwarf2_per_bfd::allocate_signatured_type)
(create_cu_from_index_list, create_cus_from_index_list)
(create_signatured_type_table_from_index)
(create_signatured_type_table_from_debug_names)
(create_addrmap_from_aranges)
(dwarf2_base_index_functions::find_last_source_symtab)
(dw_expand_symtabs_matching_file_matcher)
(dwarf2_gdb_index::expand_symtabs_matching)
(dwarf2_base_index_functions::map_symbol_filenames)
(create_cus_from_debug_names_list)
(dw2_debug_names_iterator::next)
(dwarf2_debug_names_index::expand_symtabs_matching)
(create_debug_type_hash_table, add_type_unit)
(fill_in_sig_entry_from_dwo_entry, lookup_dwo_signatured_type):
Update.
(allocate_type_unit_groups_table): Use delete.
(create_type_unit_group): Change return type. Use new.
(get_type_unit_group, build_type_psymtabs_1)
(build_type_psymtab_dependencies)
(process_skeletonless_type_unit, set_partial_user)
(dwarf2_build_psymtabs_hard, read_comp_units_from_section)
(create_cus_hash_table, queue_and_load_dwo_tu, follow_die_sig_1)
(read_signatured_type): Update.
(dwarf2_find_containing_comp_unit): Change type of
'all_comp_units'.
(run_test): Update.
(dwarf2_per_bfd::allocate_per_cu)
(dwarf2_per_bfd::allocate_signatured_type): Change return type.
Use new.
(add_signatured_type_cu_to_table): Update.
* dwarf2/index-write.c (write_one_signatured_type)
(check_dwarf64_offsets, psyms_seen_size, write_gdbindex)
(write_debug_names): Update.
While working on some changes to 'info sources' I ran into a situation
where I was seeing the same source files reported twice in the output
of the 'info sources' command when using either .gdb_index or the
.debug_name index.
I traced the problem back to some caching in
dwarf2_base_index_functions::map_symbol_filenames; when called GDB
caches the set of filenames, but, filesnames are not removed as the
index entries are expanded into full symtabs. As a result we can end
up seeing filenames reported both from a full symtab _and_ from
a (stale) previously cached index entry.
Now, obviously, when seeing a problem like this the "correct" fix is
to remove the stale entries from the cache, however, I ran a few
experiments to see why this wasn't really hitting us anywhere, and, as
far as I can tell, ::map_symbol_filenames is only called from three
places:
1. The mi command -file-list-exec-source-files,
2. The 'info sources' command, and
3. Filename completion
However, the result of this "bug" is that we will see duplicate
filenames, and readline's completion mechanism already removes
duplicates, so for case #3 we will never see any problems.
Cases #1 and #2 are basically the same, and in each case, to see a
problem we need to ensure we craft the test in a particular way, start
up ensuring we have some unexpected symtabs, then run one of the
commands to populate the cache, then expand one of the symtabs, and
list the sources again. At this point you'll see duplicate entries in
the results. Hardly surprising we haven't randomly hit this situation
in testing.
So, considering that use cases #1 and #2 are certainly not "high
performance" code (i.e. I don't think these justify the need for
caching) this leaves use case #3. Does this use justify the need for
caching? Well the psymbol_functions::map_symbol_filenames function
doesn't seem to do any extra caching, and within
dwarf2_base_index_functions::map_symbol_filenames, the only expensive
bit appears to be the call to dw2_get_file_names, and this already
does its own caching via this_cu->v.quick->file_names.
The upshot of all this analysis was that I'm not convinced the need
for the additional caching is justified, and so, I propose that to fix
the bug in GDB, I just remove the extra caching (for now).
If we later find that the caching _was_ useful, then we can
reintroduce it, but add it back such that it doesn't reintroduce this
bug.
As I was changing dwarf2_base_index_functions::map_symbol_filenames I
replaced the use of htab_up with std::unordered_set.
Tested using target_boards cc-with-debug-names and dwarf4-gdb-index.
gdb/ChangeLog:
* dwarf2/read.c: Add 'unordered_set' include.
(dwarf2_base_index_functions::map_symbol_filenames): Replace
'visited' hash table with 'qfn_cache' unordered_set. Remove use
of per_Bfd->filenames_cache cache, and use function local
filenames_cache instead. Reindent.
* dwarf2/read.h (struct dwarf2_per_bfd) <filenames_cache>: Delete.
gdb/testsuite/ChangeLog:
* gdb.base/info_sources.exp: Add new tests.
The .gdb_index was designed such that all data would be aligned.
Unfortunately, we neglected to require this alignment in the objcopy
instructions in the manual. As a result, in many cases, a .gdb_index
in the wild will not be properly aligned by mmap. This yields
undefined behavior, which is PR gdb/23743.
This patch fixes the bug by always assuming that the mapping is
unaligned, and using extract_unsigned_integer when needed. A new
helper class is introduced to make this less painful.
gdb/ChangeLog
2021-04-17 Tom Tromey <tom@tromey.com>
PR gdb/23743:
* dwarf2/read.c (class offset_view): New.
(struct symbol_table_slot): Remove.
(struct mapped_index) <symbol_table, constant_pool>: Change type.
<symbol_name_index, symbol_vec_index>: New methods.
<symbol_name_slot_invalid, symbol_name_at, symbol_name_count>:
Rewrite.
(read_gdb_index_from_buffer): Update.
(struct dw2_symtab_iterator) <vec>: Change type.
(dw2_symtab_iter_init_common, dw2_symtab_iter_init)
(dw2_symtab_iter_next, dw2_expand_marked_cus): Update.
* dwarf2/index-write.c (class data_buf) <append_data>: Remove.
<append_array, append_offset>: New methods.
(write_hash_table, add_address_entry, write_gdbindex_1)
(write_debug_names): Update.
* dwarf2/index-common.h (byte_swap, MAYBE_SWAP): Remove.
quick_symbol_functions::map_matching_symbols is only used by the Ada
code. Currently, it both expands certain psymtabs and then walks over
the full symtabs -- including any already-expanded ones -- calling a
callback.
It appears to work lazily as well, in that if the callback returns
false, iteration stops. However, only the psymtab implementation does
this; the DWARF index implementations are not lazy. It turns out,
though, that the only callback that is ever passed here never returns
false.
This patch simplifies this method by removing the callback. The
method is also renamed. In the new scheme, the caller is responsible
for walking the full symtabs, which removes some redundancy as well.
gdb/ChangeLog
2021-04-17 Tom Tromey <tom@tromey.com>
* psymtab.c (psymbol_functions::expand_matching_symbols): Rename
from map_matching_symbols. Change parameters.
* psympriv.h (struct psymbol_functions) <expand_matching_symbols>:
Rename from map_matching_symbols. Change parameters.
* dwarf2/read.c (struct dwarf2_gdb_index)
<expand_matching_symbols>: Rename from map_matching_symbols.
Change parameters.
(struct dwarf2_debug_names_index) <expand_matching_symbols>:
Rename from map_matching_symbols. Change parameters.
(dwarf2_gdb_index::expand_matching_symbols): Rename from
dw2_map_matching_symbols. Change parameters.
(dwarf2_gdb_index::expand_matching_symbols): Remove old
implementation.
(dwarf2_debug_names_index::expand_matching_symbols): Rename from
map_matching_symbols. Change parameters.
* objfiles.h (struct objfile) <expand_matching_symbols>: Rename
from map_matching_symbols. Change parameters.
* symfile-debug.c (objfile::expand_matching_symbols): Rename from
map_matching_symbols. Change parameters.
* ada-lang.c (map_matching_symbols): New function.
(add_nonlocal_symbols): Update.
This removes quick_symbol_functions::expand_symtabs_with_fullname,
replacing it with a call to expand_symtabs_matching. As with the
previous patches, the implementation is consolidated in the objfile
method.
gdb/ChangeLog
2021-04-17 Tom Tromey <tom@tromey.com>
* quick-symbol.h (struct quick_symbol_functions)
<expand_symtabs_with_fullname>: Remove.
* psymtab.c (psymbol_functions::expand_symtabs_with_fullname):
Remove.
* psympriv.h (struct psymbol_functions)
<expand_symtabs_with_fullname>: Remove.
* dwarf2/read.c (struct dwarf2_base_index_functions)
<expand_symtabs_with_fullname>: Remove.
(dwarf2_base_index_functions::expand_symtabs_with_fullname):
Remove.
* objfiles.h (struct objfile) <expand_symtabs_with_fullname>:
Update comment.
* symfile-debug.c (objfile::expand_symtabs_with_fullname):
Rewrite.
This replaces quick_symbol_functions::map_symtabs_matching_filename
with a call to expand_symtabs_matching. As with the previous patch,
rather than update all callers, the implementation is consolidated in
objfile::map_symtabs_matching_filename.
gdb/ChangeLog
2021-04-17 Tom Tromey <tom@tromey.com>
* symfile-debug.c (objfile::map_symtabs_matching_filename):
Rewrite.
* quick-symbol.h (struct quick_symbol_functions)
<map_symtabs_matching_filename>: Remove.
* psymtab.c (partial_map_expand_apply)
(psymbol_functions::map_symtabs_matching_filename): Remove.
* psympriv.h (struct psymbol_functions)
<map_symtabs_matching_filename>: Remove.
* objfiles.h (struct objfile) <map_symtabs_matching_filename>:
Update comment.
* dwarf2/read.c (struct dwarf2_base_index_functions)
<map_symtabs_matching_filename>: Remove.
(dw2_map_expand_apply)
(dwarf2_base_index_functions::map_symtabs_matching_filename):
Remove.
This removes quick_symbol_functions, replacing it with calls to
expand_symtabs_matching. Because the replacement is somewhat verbose,
objfile::lookup_symbol is not removed. This consolidates some
duplicated code into this one spot.
gdb/ChangeLog
2021-04-17 Tom Tromey <tom@tromey.com>
* symfile-debug.c (objfile::lookup_symbol): Rewrite.
* quick-symbol.h (struct quick_symbol_functions) <lookup_symbol>:
Remove.
* psymtab.c (psymbol_functions::lookup_symbol): Remove.
* psympriv.h (struct psymbol_functions) <lookup_symbol>: Remove.
* objfiles.h (struct objfile) <lookup_symbol>: Add comment.
* dwarf2/read.c (struct dwarf2_gdb_index) <lookup_symbol>:
Remove.
(struct dwarf2_debug_names_index) <lookup_symbol>: Remove.
(dwarf2_gdb_index::lookup_symbol)
(dwarf2_debug_names_index::lookup_symbol): Remove.
GDB reports duplicate local vars with "<optimized out>" values for
inlined functions that are compiled with Clang.
Suppose we have
__attribute__((always_inline))
static void aFunction() {
int a = 42;
if(a > 2) {
int value = a;
value += 10; /* break here */
}
}
The "info locals" command at the "break here" line gives the following
output:
...
Breakpoint 1, aFunction () at test.c:6
6 value += 10; /* break here */
(gdb) info locals
value = 42
a = 42
value = <optimized out>
(gdb)
The reason is, inlined functions that are compiled by Clang do not
contain DW_AT_abstract_origin attributes in the DW_TAG_lexical_block
entries. See
https://bugs.llvm.org/show_bug.cgi?id=49953
E.g. the DIE of the inlined function above is
0x00000087: DW_TAG_inlined_subroutine
DW_AT_abstract_origin (0x0000002a "aFunction")
DW_AT_low_pc (0x00000000004004b2)
DW_AT_high_pc (0x00000000004004d2)
DW_AT_call_file ("/tmp/test.c")
DW_AT_call_line (11)
DW_AT_call_column (0x03)
0x0000009b: DW_TAG_variable
DW_AT_location (DW_OP_fbreg -4)
DW_AT_abstract_origin (0x00000032 "a")
0x000000a3: DW_TAG_lexical_block
DW_AT_low_pc (0x00000000004004c3)
DW_AT_high_pc (0x00000000004004d2)
0x000000b0: DW_TAG_variable
DW_AT_location (DW_OP_fbreg -8)
DW_AT_abstract_origin (0x0000003e "value")
This causes GDB to fail matching the concrete lexical scope with the
corresponding abstract entry. Hence, the local vars of the abstract
function that are contained in the lexical scope are read separately
(and thus, in addition to) the local vars of the concrete scope.
Because the abstract definitions of the vars do not contain location
information, we see the extra 'value = <optimized out>' above.
This bug is highly related to PR gdb/25695, but the root cause is not
exactly the same. In PR gdb/25695, GCC emits an extra
DW_TAG_lexical_block without an DW_AT_abstract_origin that wraps the
body of the inlined function. That is, the trees of the abstract DIE
for the function and its concrete instance are structurally not the
same. In the case of using Clang, the trees have the same structure.
To tackle the Clang case, when traversing the children of the concrete
instance root, keep a reference to the child of the abstract DIE that
corresponds to the concrete child, so that we can match the two DIEs
heuristically in case of missing DW_AT_abstract_origin attributes.
The updated gdb.opt/inline-locals.exp test has been checked with GCC
5-10 and Clang 5-11.
gdb/ChangeLog:
2021-04-14 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* dwarf2/read.c (inherit_abstract_dies): Keep a reference to the
corresponding child of the abstract DIE when iterating the
children of the concrete DIE.
gdb/testsuite/ChangeLog:
2021-04-14 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.opt/inline-locals.c (scoped): New function.
(main): Call 'scoped'.
* gdb.opt/inline-locals.exp: Update with "info locals" tests
for scoped variables.
* gdb.dwarf2/dw2-inline-with-lexical-scope.c: New file.
* gdb.dwarf2/dw2-inline-with-lexical-scope.exp: New file.
DWARF allows .dwo file paths to be relative rather than absolute.
When they are relative, DWARF uses DW_AT_comp_dir to find the .dwo
file. DW_AT_comp_dir can also be relative, making the entire search
patch for the .dwo file relative.
In this case, GDB currently searches relative to its current working
directory, i.e. the directory from which the debugger was launched,
but not relative to the directory containing the built binary. This
cannot be right, as the compiler, when generating the relative paths,
knows where it's building the binary but can have no idea where the
debugger will be launched.
The correct thing is to add the directory containing the binary to the
search paths used for resolving relative locations of dwo files. That
is what this patch does.
gdb/ChangeLog:
* dwarf2/read.c (try_open_dwop_file): Add path for the binary to
the search paths used resolve relative location of .dwo file.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/fission-relative-dwo.c: New file.
* gdb.dwarf2/fission-relative-dwo.exp: New file.
Since partial_symtab is supposed to be objfile-independent (since series
[1]), I think it would make sense for partial_symtab to not take an
objfile as a parameter in its constructor.
This patch replaces that parameter with an objfile_per_bfd_storage
parameter.
The objfile is used for two things:
- to get the objfile_name, for debug messages. We can get that name
from the bfd instead.
- to intern the partial symtab filename. Even though it goes through
an objfile method, the request is actually forwarded to the
underlying objfile_per_bfd_storage. So we can ask the new
objfile_per_bfd_storage instead.
In order to get a reference to the BFD from the objfile_per_bfd_storage,
the BFD is saved in the objfile_per_bfd_storage object.
[1] https://sourceware.org/pipermail/gdb-patches/2021-February/176625.html
gdb/ChangeLog:
* psympriv.h (struct partial_symtab) <partial_symtab>: Change
objfile parameter for objfile_per_bfd_storage, adjust callers.
(struct standard_psymtab) <standard_psymtab>: Likewise.
(struct legacy_psymtab) <legacy_psymtab>: Likewise.
* psymtab.c (partial_symtab::partial_symtab): Likewise.
* ctfread.c (struct ctf_psymtab): Likewise.
* dwarf2/read.h (struct dwarf2_psymtab): Likewise.
* dwarf2/read.c (struct dwarf2_include_psymtab): Likewise.
(dwarf2_create_include_psymtab): Likewise.
* objfiles.h (struct objfile_per_bfd_storage)
<objfile_per_bfd_storage>: Add bfd parameter, adjust callers.
<get_bfd>: New method.
<m_bfd>: New field.
* objfiles.c (get_objfile_bfd_data): Adjust.
Change-Id: I2ed3ab5d2e6f27d034bd4dc26ae2fae7b0b8a2b9
Add the `is_flag_enum` and `set_is_flag_enum` methods on `struct type`,
in order to remove the `TYPE_FLAG_ENUM` macro. In this patch, the macro
is changed to use the getter, so all the call sites of the macro that
are used as a setter are changed to use the setter method directly. The
next patch will remove the macro completely.
gdb/ChangeLog:
* gdbtypes.h (struct type) <is_flag_enum,
set_is_flag_enum>: New methods.
(TYPE_FLAG_ENUM): Use type::is_flag_enum, change all
write call sites to use type::set_is_flag_enum.
Change-Id: I9c56c91626c8d784947ba94fcb97818526b81d1c
Add the `is_declared_class` and `set_is_declared_class` methods on
`struct type`, in order to remove the `TYPE_DECLARED_CLASS` macro. In
this patch, the macro is changed to use the getter, so all the call
sites of the macro that are used as a setter are changed to use the
setter method directly. The next patch will remove the macro
completely.
gdb/ChangeLog:
* gdbtypes.h (struct type) <is_declared_class,
set_is_declared_class>: New methods.
(TYPE_DECLARED_CLASS): Use type::is_declared_class, change all
write call sites to use type::set_is_declared_class.
Change-Id: Idf08d32e137c885a0aba0a18f556a899c1cbfd68
This removes dw2_map_matching_symbols and dw2_expand_symtabs_matching,
merging them with their sole trivial callers.
gdb/ChangeLog
2021-03-31 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_gdb_index::map_matching_symbols): Merge
with dw2_map_matching_symbols.
(dwarf2_gdb_index::expand_symtabs_matching): Merge with
dw2_expand_symtabs_matching.
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:
efb763a5ea ("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 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 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.
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.
