This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.
Make comp_unit_head.length private, to enforce using accessor functions.
Replace accessor function get_length with get_length_with_initial and
get_length_without_initial, to make it explicit which variant we're using.
Tested on x86_64-linux.
PR symtab/29343
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29343
PR symtab/29343 points out that it would be beneficial if
comp_unit_head had a constructor and used initializers. This patch
implements this. I'm unsure if this is sufficient to close the bug,
but at least it's a step.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29343
When asking GDB to print a variable from an imported namespace, we only
want to see variables imported in lines that the inferior has already
gone through, as is being tested last in gdb.cp/nsusing.exp. However
with the proposed change to gdb.cp/nsusing.exp, we get the following
failures:
(gdb) PASS: gdb.cp/nsusing.exp: continue to breakpoint: marker10 stop
print x
$9 = 911
(gdb) FAIL: gdb.cp/nsusing.exp: print x, before using statement
next
15 y += x;
(gdb) PASS: gdb.cp/nsusing.exp: using namespace M
print x
$10 = 911
(gdb) PASS: gdb.cp/nsusing.exp: print x, only using M
Showing that the feature wasn't functioning properly, it just so
happened that gcc ordered the namespaces in a convenient way.
This happens because GDB doesn't take into account the line where the
"using namespace" directive is written. So long as it shows up in the
current scope, we assume it is valid.
To fix this, add a new member to struct using_direct, that stores the
line where the directive was written, and a new function that informs if
the using directive is valid already.
Unfortunately, due to a GCC bug, the failure still shows up. Compilers
that set the declaration line of the using directive correctly (such as
Clang) do not show such a bug, so the test includes an XFAIL for gcc
code.
Finally, because the final test of gdb.cp/nsusing.exp has turned into
multiple that all would need XFAILs for older GCCs (<= 4.3), and that
GCC is very old, if it is detected, the test just exits early.
Approved-by: Tom Tromey <tom@tromey.com>
PR symtab/29105 shows a number of situations where symbol lookup can
result in the expansion of too many CUs.
What happens is that lookup_signed_typename will try to look up a type
like "signed int". In cooked_index_functions::expand_symtabs_matching,
when looping over languages, the C++ case will canonicalize this type
name to be "int" instead. Then this method will proceed to expand
every CU that has an entry for "int" -- i.e., nearly all of them. A
crucial component of this is that the caller, objfile::lookup_symbol,
does not do this canonicalization, so when it tries to find the symbol
for "signed int", it fails -- causing the loop to continue.
This patch fixes the problem by introducing name canonicalization for
C. The idea here is that, by making C and C++ agree on the canonical
name when a symbol name can have multiple spellings, we avoid the bad
behavior in objfile::lookup_symbol (and any other such code -- I don't
know if there is any).
Unlike C++, C only has a few situations where canonicalization is
needed. And, in particular, due to the lack of overloading (thus
avoiding any issues in linespec) and due to the way c-exp.y works, I
think that no canonicalization is needed during symbol lookup -- only
during symtab construction. This explains why lookup_name_info is not
touched.
The stabs reader is modified on a "best effort" basis.
The DWARF reader needed one small tweak in dwarf2_name to avoid a
regression in dw2-unusual-field-names.exp. I think this is adequately
explained by the comment, but basically this is a scenario that should
not occur in real code, only the gdb test suite.
lookup_signed_typename is simplified. It used to search for two
different type names, but now gdb can search just for the canonical
form.
gdb.dwarf2/enum-type.exp needed a small tweak, because the
canonicalizer turns "unsigned integer" into "unsigned int integer".
It seems better here to use the correct C type name.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29105
Tested-by: Simon Marchi <simark@simark.ca>
Reviewed-by: Andrew Burgess <aburgess@redhat.com>
dwarf2_compute_name has a redundant check of the CU's language -- this
is also checked in dwarf2_canonicalize_name. Removing this slightly
simplifies a future patch.
Reviewed-by: Andrew Burgess <aburgess@redhat.com>
While testing the fix for PR 29105, I noticed I couldn't ctrl-C my way
out of GDB expanding many symtabs. GDB was busy in a loop in
cooked_index_functions::expand_symtabs_matching. Add a QUIT there. I
also happened to see a spot in
cooked_index_functions::expand_matching_symbols where a QUIT would be
useful too, since we iterate over a potentially big number of index
entries and expand CUs in the loop. Add one there too.
Change-Id: Ie1d650381df7f944c16d841b3e592d2dce7306c3
Approved-By: Kevin Buettner <kevinb@redhat.com>
Valgrind reports a leak in the dwarf reader (see details below).
The function dw2_get_file_names_reader is interning in the per_objfile
all the file names it finds, except the name of 'fnd file name and directory'.
Instead, it was xstrdup-ing the name.
Fix the leaks by also interning the name.
This was validated running the tests natively, and under valgrind.
Leaks have decreased as mentionned below.
Valgrind detected no error such as double free or use after free.
Stack trace of the leak:
==4113266== 490,735 bytes in 17,500 blocks are definitely lost in loss record 7,061 of 7,074
==4113266== at 0x483979B: malloc (vg_replace_malloc.c:393)
==4113266== by 0x25A454: xmalloc (alloc.c:57)
==4113266== by 0x7D1E1E: xstrdup (xstrdup.c:34)
==4113266== by 0x39D141: dw2_get_file_names_reader (read.c:2825)
==4113266== by 0x39D141: dw2_get_file_names(dwarf2_per_cu_data*, dwarf2_per_objfile*) (read.c:2851)
==4113266== by 0x39DD6C: dw_expand_symtabs_matching_file_matcher(dwarf2_per_objfile*, gdb::function_view<bool (char const*, bool)>) (read.c:4149)
==4113266== by 0x3BC8B5: cooked_index_functions::expand_symtabs_matching(objfile*, gdb::function_view<bool (char const*, bool)>, lookup_name_info const*, gdb::function_view<bool (char const*)>, gdb::function_view<bool (compunit_symtab*)>, enum_flags<block_search_flag_values>, domain_enum, search_domain) (read.c:18688)
==4113266== by 0x5DD1EA: objfile::map_symtabs_matching_filename(char const*, char const*, gdb::function_view<bool (symtab*)>) (symfile-debug.c:207)
==4113266== by 0x5F04CC: iterate_over_symtabs(char const*, gdb::function_view<bool (symtab*)>) (symtab.c:633)
==4113266== by 0x477EE3: collect_symtabs_from_filename(char const*, program_space*) (linespec.c:3712)
==4113266== by 0x477FC1: symtabs_from_filename(char const*, program_space*) (linespec.c:3726)
==4113266== by 0x47A9B8: convert_explicit_location_spec_to_linespec(linespec_state*, linespec*, char const*, char const*, symbol_name_match_type, char const*, line_offset) (linespec.c:2329)
==4113266== by 0x47E86E: convert_explicit_location_spec_to_sals (linespec.c:2388)
==4113266== by 0x47E86E: location_spec_to_sals(linespec_parser*, location_spec const*) (linespec.c:3104)
==4113266== by 0x47EDAC: decode_line_full(location_spec*, int, program_space*, symtab*, int, linespec_result*, char const*, char const*) (linespec.c:3149)
...
Without the fix, the top 10 leaks are:
./gdb/testsuite/outputs/gdb.base/condbreak-bad/gdb.log:345:==3213924== definitely lost: 130,937 bytes in 5,409 blocks
./gdb/testsuite/outputs/gdb.base/hbreak2/gdb.log:619:==3758919== definitely lost: 173,323 bytes in 7,204 blocks
./gdb/testsuite/outputs/gdb.mi/mi-var-cp/gdb.log:1320:==4152873== definitely lost: 172,826 bytes in 7,207 blocks
./gdb/testsuite/outputs/gdb.base/advance-until-multiple-locations/gdb.log:398:==2992643== definitely lost: 172,965 bytes in 7,211 blocks
./gdb/testsuite/outputs/gdb.mi/mi-var-cmd/gdb.log:2302:==4159476== definitely lost: 173,129 bytes in 7,211 blocks
./gdb/testsuite/outputs/gdb.cp/gdb2384/gdb.log:222:==3811851== definitely lost: 218,106 bytes in 7,761 blocks
./gdb/testsuite/outputs/gdb.cp/mb-templates/gdb.log:310:==3787344== definitely lost: 290,311 bytes in 10,340 blocks
./gdb/testsuite/outputs/gdb.mi/mi-var-rtti/gdb.log:2568:==4158350== definitely lost: 435,427 bytes in 15,507 blocks
./gdb/testsuite/outputs/gdb.mi/mi-catch-cpp-exceptions/gdb.log:1704:==4119722== definitely lost: 435,405 bytes in 15,510 blocks
./gdb/testsuite/outputs/gdb.mi/mi-vla-fortran/gdb.log:768:==4113266== definitely lost: 508,585 bytes in 18,109 blocks
With the fix:
./gdb/testsuite/outputs/gdb.base/fork-running-state/gdb.log:1536:==2924193== indirectly lost: 13,848 bytes in 98 blocks
./gdb/testsuite/outputs/gdb.base/fork-running-state/gdb.log:1675:==2928777== indirectly lost: 13,848 bytes in 98 blocks
./gdb/testsuite/outputs/gdb.python/py-inferior-leak/gdb.log:4729:==3353335== definitely lost: 3,360 bytes in 140 blocks
./gdb/testsuite/outputs/gdb.base/kill-detach-inferiors-cmd/gdb.log:210:==2746927== indirectly lost: 13,246 bytes in 154 blocks
./gdb/testsuite/outputs/gdb.base/inferior-clone/gdb.log:179:==3034984== indirectly lost: 12,921 bytes in 161 blocks
./gdb/testsuite/outputs/gdb.base/interrupt-daemon/gdb.log:209:==3006248== indirectly lost: 20,683 bytes in 174 blocks
./gdb/testsuite/outputs/gdb.threads/watchpoint-fork/gdb.log:714:==3512403== indirectly lost: 20,707 bytes in 175 blocks
./gdb/testsuite/outputs/gdb.threads/watchpoint-fork/gdb.log:962:==3514498== indirectly lost: 20,851 bytes in 178 blocks
./gdb/testsuite/outputs/gdb.base/multi-forks/gdb.log:336:==2585839== indirectly lost: 53,630 bytes in 386 blocks
./gdb/testsuite/outputs/gdb.base/multi-forks/gdb.log:1338:==2592417== indirectly lost: 100,008 bytes in 1,154 blocks
Approved-By: Simon Marchi <simon.marchi@efficios.com>
If we instrument cc-with-tweaks.sh to remove the .gnu_debugaltlink file after
dwz has created it, with test-case
gdb.threads/access-mem-running-thread-exit.exp and target board cc-with-dwz-m
we run into:
...
(gdb) file access-mem-running-thread-exit^M
Reading symbols from access-mem-running-thread-exit...^M
could not find '.gnu_debugaltlink' file for access-mem-running-thread-exit^M
...
followed a bit later by:
...
(gdb) file access-mem-running-thread-exit^M
Reading symbols from access-mem-running-thread-exit...^M
gdb/dwarf2/read.c:7284: internal-error: create_all_units: \
Assertion `per_objfile->per_bfd->all_units.empty ()' failed.^M
...
The problem is that create_units does not catch the error thrown by
dwarf2_get_dwz_file.
Fix this by catching the error and performing the necessary cleanup, getting
the same result for the first and second file command.
PR symtab/29805
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29805
Clang up to version 15 (current) adds macros that were defined in the
command line or by "other means", according to the Dwarf specification,
after the last DW_MACRO_end_file, instead of before the first
DW_MACRO_start_file, as the specification dictates. When GDB reads the
macros after the last file is closed, the macros never end up "in scope"
and so we can't print them. This has been submitted as a bug to Clang
developers (https://github.com/llvm/llvm-project/issues/54506), and PR
macros/29034 was opened for GDB to keep track of this.
Seeing as there is no expected date for it to be fixed, add a workaround
for all current versions of Clang. The workaround detects when
the main file would be closed and if the producer is Clang, and turns
that operation into a noop, so we keep a reference to the current_file
as those macros are read.
A test case was added to confirm the functionality, and the KFAIL for
running gdb.base/macro-source-path when using clang.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29034
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Small cleanup to use std::vector iterators rather than raw pointers.
Approved-By: Tom Tromey <tom@tromey.com>
Change-Id: I8d50dbb3f2d8dad7ff94066a578d523f1f31b590
When building GDB with clang and --enable-ubsan, I get:
UNRESOLVED: gdb.dwarf2/frame-inlined-in-outer-frame.exp: starti prompt
The cause being:
$ ./gdb --data-directory=data-directory -nx -q -readnow testsuite/outputs/gdb.dwarf2/frame-inlined-in-outer-frame/frame-inlined-in-outer-frame
Reading symbols from testsuite/outputs/gdb.dwarf2/frame-inlined-in-outer-frame/frame-inlined-in-outer-frame...
Expanding full symbols from testsuite/outputs/gdb.dwarf2/frame-inlined-in-outer-frame/frame-inlined-in-outer-frame...
/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:11954:47: runtime error: applying non-zero offset 8 to null pointer
I found this to happen with ld-linux on at least Arch Linux and Ubuntu
22.04:
$ ./gdb --data-directory=data-directory -nx -q -readnow -iex "set debuginfod enabled on" /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/ld-linux-x86-64.so.2...
Reading symbols from /home/simark/.cache/debuginfod_client/22bd7a2c03d8cfc05ef7092bfae5932223189bc1/debuginfo...
Expanding full symbols from /home/simark/.cache/debuginfod_client/22bd7a2c03d8cfc05ef7092bfae5932223189bc1/debuginfo...
/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:11954:47: runtime error: applying non-zero offset 8 to null pointer
The problem happens when doing this:
sect_offset *offsetp = offsets.data () + 1
When `offsets` is an empty vector, `offsets.data ()` returns nullptr.
Fix it by wrapping that in a `!offsets.empty ()` check.
Change-Id: I6d29ba2fe80ba4308f68effd9c57d4ee8d67c29f
Approved-By: Tom Tromey <tom@tromey.com>
PR symtab/29694 points out a regression caused by the new DWARF
scanner when the cc-with-gdb-index target board is used.
What happens here is that an older version of gdb will make an index
describing the "A" type as:
[737] A: 1 [global, type]
whereas the new gdb says:
[1008] A: 0 [global, type]
Here the old one is correct because the A in CU 0 is just a
declaration without a size:
<1><45>: Abbrev Number: 10 (DW_TAG_structure_type)
<46> DW_AT_name : A
<48> DW_AT_declaration : 1
<48> DW_AT_sibling : <0x6d>
This patch fixes the problem by introducing the idea of a "type
declaration". I think gdb still needs to recurse into these types,
searching for methods, but by marking the type itself as a
declaration, gdb can skip this type during lookups and when writing
the index.
Regression tested on x86-64 using the cc-with-gdb-index board.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29694
A user found a bug where an array of packed arrays was printed
incorrectly. The bug here is that the packed array has a bit stride,
but the outer array does not -- and should not. However,
update_static_array_size does not distinguish between an array of
packed arrays and a multi-dimensional packed array, and for the
latter, only the innermost array will end up with a stride.
This patch fixes the problem by adding a flag to indicate whether a
given array type is a constituent of a multi-dimensional array.
The compiler will sometimes emit a linkage name for a type, like:
<1d3> DW_AT_linkage_name: (indirect string, offset: 0x106f): 11__mbstate_t
These names aren't very useful, and this patch changes the DWARF
reader so that they are ignored by the cooked index.
This patch changes a few more uses of static_cast to use
checked_static_cast. In this patch, cast-to-references are converted
by moving the dereference outside of the cast, as checked_static_cast
only handles pointers.
After committing 8ba677d356 ("[gdb/symtab] Don't complain about function
decls") I noticed that quite a bit of code in read_func_scope is used to decide
whether to issue the "cannot get low and high bounds for subprogram DIE at
$hex" complaint, which executes unnecessarily if we have the default
"set complaints 0".
Fix this by (NFC):
- factoring out new static function have_complaint from macro complaint, and
- using it to wrap the relevant code in read_func_scope.
Tested on x86_64-linux.
[ Requires "[gdb/symtab] Don't complain about inlined functions" as
submitted here (
https://sourceware.org/pipermail/gdb-patches/2022-September/191762.html ). ]
With the test-case included in this patch, we get:
...
(gdb) ptype main^M
During symbol reading: cannot get low and high bounds for subprogram DIE \
at 0xc1^M
type = int (void)^M
(gdb) FAIL: gdb.dwarf2/anon-ns-fn.exp: ptype main without complaints
...
The DIE causing the complaint is a function declaration:
...
<2><c1>: Abbrev Number: 3 (DW_TAG_subprogram)
<c2> DW_AT_name : foo
<c8> DW_AT_declaration : 1
...
which is referred to from the DIE representing the function definition:
...
<1><f4>: Abbrev Number: 7 (DW_TAG_subprogram)
<f5> DW_AT_specification: <0xc1>
<f9> DW_AT_low_pc : 0x4004c7
<101> DW_AT_high_pc : 0x7
...
which does contain the low and high bounds.
Fix this by not complaining about function declarations.
Tested on x86_64-linux.
With the test-case included in this patch, we get:
...
(gdb) ptype main^M
During symbol reading: cannot get low and high bounds for subprogram DIE \
at 0x113^M
During symbol reading: cannot get low and high bounds for subprogram DIE \
at 0x11f^M
type = int (void)^M
(gdb) FAIL: gdb.dwarf2/inline.exp: ptype main
...
The complaints are about foo, with DW_AT_inline == DW_INL_inlined:
...
<1><11f>: Abbrev Number: 6 (DW_TAG_subprogram)
<120> DW_AT_name : foo
<126> DW_AT_prototyped : 1
<126> DW_AT_type : <0x10c>
<12a> DW_AT_inline : 1 (inlined)
...
and foo2, with DW_AT_inline == DW_INL_declared_inlined:
...
<1><113>: Abbrev Number: 5 (DW_TAG_subprogram)
<114> DW_AT_name : foo2
<11a> DW_AT_prototyped : 1
<11a> DW_AT_type : <0x10c>
<11e> DW_AT_inline : 3 (declared as inline and inlined)
...
Fix this by not complaining about inlined functions.
Tested on x86_64-linux.
Add all_comp_units/all_type_units views on all_units.
Having the views allows us to:
- easily get the number of CUs or TUs in all_units, and
- easily access the nth CU or TU.
This minimizes the use of tu_stats.nr_tus.
Tested on x86_64-linux.
Add the `length` and `set_length` methods on `struct type`, in order to remove
the `TYPE_LENGTH` 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.
Change-Id: Id1090244f15c9856969b9be5006aefe8d8897ca4
Add the `target_type` and `set_target_type` methods on `struct type`, in order
to remove the `TYPE_TARGET_TYPE` 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.
Change-Id: I85ce24d847763badd34fdee3e14b8c8c14cb3161
With the test-case included in this commit, we run into this FAIL:
...
(gdb) p var^M
During symbol reading: file index out of range^M
$1 = 0^M
(gdb) FAIL: gdb.dwarf2/dw2-no-code-cu.exp: p var with no complaints
...
This is a regression since commit 6d263fe46e ("Avoid bad breakpoints with
--gc-sections"), which contains this change in read_file_scope:
...
- handle_DW_AT_stmt_list (die, cu, fnd, lowpc);
+ if (lowpc != highpc)
+ handle_DW_AT_stmt_list (die, cu, fnd, lowpc);
...
The change intends to avoid a problem with a check in
lnp_state_machine::check_line_address, but also prevents the file and dir
tables from being read, which causes the complaint.
Fix the FAIL by reducing the scope of the "lowpc != highpc" condition to the
call to dwarf_decode_lines in handle_DW_AT_stmt_list.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29561
With the test-case included in the patch, we run into:
...
(gdb) info types -q std::nullptr_t^M
During symbol reading: unsupported tag: 'DW_TAG_unspecified_type'^M
^M
File /usr/include/c++/7/x86_64-suse-linux/bits/c++config.h:^M
2198: typedef decltype(nullptr) std::nullptr_t;^M
(gdb) FAIL: gdb.dwarf2/nullptr_t.exp: info types -q std::nullptr_t \
without complaint
...
Fix the complaint by handling DW_TAG_unspecified_type in new_symbol, and verify
in the test-case using "maint print symbols" that the symbol exists.
Tested on x86_64-linux, with gcc 7.5.0 and clang 13.0.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=17271
Currently, the test-case contained in this patch fails:
...
(gdb) p (int) foo ()^M
Invalid cast.^M
(gdb) FAIL: gdb.dwarf2/dw2-unspecified-type.exp: p (int) foo ()
...
because DW_TAG_unspecified_type is translated as void.
There's some code in read_unspecified_type that marks the type as stub, but
that's only active for ada:
...
if (cu->lang () == language_ada)
type->set_is_stub (true);
...
Fix this by:
- marking the type as a stub for all languages, and
- handling the stub return type case in call_function_by_hand_dummy.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29558
When running test-case gdb.cp/cpexprs-debug-types.exp on target board
cc-with-debug-names/gdb:debug_flags=-gdwarf-5, we get an executable with
a .debug_names section, but no .debug_types section. For dwarf-5, the TUs
are no longer put in a separate unit, but instead they're put in the
.debug_info section.
When loading the executable, the .debug_names section is silently ignored
because of this check in dwarf2_read_debug_names:
...
if (map->tu_count != 0)
{
/* We can only handle a single .debug_types when we have an
index. */
if (per_bfd->types.size () != 1)
return false;
...
which triggers because per_bfd->types.size () == 0.
The intention of the check is to make sure we don't have more that one
.debug_types section, as can happen in a object file (see PR12984):
...
$ grep "\.debug_types" 11.s
.section .debug_types,"G",@progbits,wt.75c042c23a9a07ee,comdat
.section .debug_types,"G",@progbits,wt.c59c413bf50a4607,comdat
...
Fix this by:
- changing the check condition to "per_bfd->types.size () > 1", and
- handling per_bfd->types.size () == 0.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29385
The following GDB behavior was also reported as a GDB bug in
https://sourceware.org/bugzilla/show_bug.cgi?id=28396
I will reiterate the problem a bit and give some more information here.
This patch closes the above mentioned bug.
The DWARF 5 standard 2.23 'Template Parameters' reads:
A template type parameter is represented by a debugging information
entry with the tag DW_TAG_template_type_parameter. A template value
parameter is represented by a debugging information entry with the tag
DW_TAG_template_value_parameter. The actual template parameter entries
appear in the same order as the corresponding template formal
parameter declarations in the source progam.
A type or value parameter entry may have a DW_AT_name attribute, whose
value is a null-terminated string containing the name of the
corresponding formal parameter.
So the DW_AT_name attribute for DW_TAG_template_type_parameter and
DW_TAG_template_value_parameter is optional.
Within GDB, creating a new symbol from some read DIE usually requires the
presence of a DW_AT_name for the DIE (an exception here is the case of
unnamed namespaces or the existence of a linkage name).
This patch makes the presence of the DW_AT_name for template value/type
tags optional, similar to the unnamed namespaces.
For unnamed namespaces dwarf2_name simply returns the constant string
CP_ANONYMOUS_NAMESPACE_STR '(anonymous namespace)'. For template tags a
case was added to the switch statement calling the
unnamed_template_tag_name helper. Within the scope of parent which
the template parameter is a child of, the helper counts the position
of the template tag within the unnamed template tags and returns
'<unnamedNUMBER>' where NUMBER is its position. This way we end up with
unique names within the respective scope of the function/class/struct
(these are the only currenltly supported template kinds within GDB and
usually the compilers) where we discovered the template tags in.
While I do not know of a way to bring GCC to emit template tags without
names there is one for clang/icpx. Consider the following example
template<typename A, typename B, typename C>
class Foo {};
template<typename, typename B, typename>
class Foo;
int main () {
Foo<double, int, float> f;
return 0;
}
The forward declaration for 'Foo' with the missing template type names
'A' and 'C' makes clang emit a bunch of template tags without names:
...
<2><43>: Abbrev Number: 3 (DW_TAG_variable)
<44> DW_AT_location : 2 byte block: 91 78 (DW_OP_fbreg: -8)
<47> DW_AT_name : (indirect string, offset: 0x63): f
<4b> DW_AT_decl_file : 1
<4c> DW_AT_decl_line : 8
<4d> DW_AT_type : <0x59>
...
<1><59>: Abbrev Number: 5 (DW_TAG_class_type)
<5a> DW_AT_calling_convention: 5 (pass by value)
<5b> DW_AT_name : (indirect string, offset: 0x74): Foo<double, int, float>
<5f> DW_AT_byte_size : 1
<60> DW_AT_decl_file : 1
<61> DW_AT_decl_line : 2
<2><62>: Abbrev Number: 6 (DW_TAG_template_type_param)
<63> DW_AT_type : <0x76>
<2><67>: Abbrev Number: 7 (DW_TAG_template_type_param)
<68> DW_AT_type : <0x52>
<6c> DW_AT_name : (indirect string, offset: 0x6c): B
<2><70>: Abbrev Number: 6 (DW_TAG_template_type_param)
<71> DW_AT_type : <0x7d>
...
Befor this patch, GDB would not create any symbols for the read template
tag DIEs and thus lose knowledge about them. Breaking at the return
statement and printing f's type would read
(gdb) ptype f
type = class Foo<double, int, float> [with B = int] {
<no data fields>
}
After this patch GDB does generate symbols from the DWARF (with their
artificial names:
(gdb) ptype f
type = class Foo<double, int, float> [with <unnamed0> = double, B = int,
<unnamed1> = float] {
<no data fields>
}
The same principle theoretically applies to template functions. Also
here, GDB would not record unnamed template TAGs but I know of no visual
way to trigger and test this changed behavior. Template functions do
not emit a '[with...]' list and their name generation also does not
suffer from template tags without names. GDB does not check whether or
not a template tag has a name in 'dwarf2_compute_name' and thus, the
names of the template functions are created independently of whether or
not the template TAGs have a DW_TAT_name attribute. A testcase has
been added in the gdb.dwarf2 for template classes and structs.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28396
When running the included test-case, we run into:
...
(gdb) break _start^M
read.h:309: internal-error: set_length: \
Assertion `m_length == length' failed.^M
...
The problem is that while there are two CUs:
...
$ readelf -wi debug-names-missing-cu | grep @
Compilation Unit @ offset 0x0:
Compilation Unit @ offset 0x2d:
...
the CU table in the .debug_names section only contains the first one:
...
CU table:
[ 0] 0x0
...
The incomplete CU table makes create_cus_from_debug_names_list set the size of
the CU at 0x0 to the actual size of both CUs combined.
This eventually leads to the assert, when we read the actual size from the CU
header.
While having an incomplete CU table in a .debug_names section is incorrect,
we need a better failure mode than asserting.
The easiest way to fix this is to set the length to 0 (meaning: unkown) in
create_cus_from_debug_names_list.
This makes the failure mode to accept the incomplete CU table, but to ignore
the missing CU.
It would be nice to instead reject the .debug_names index, and build a
complete CU list, but the point where we find this out is well after
dwarf2_initialize_objfile, so it looks rather intrusive to restart at that
point.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29453
When loading the debug-names-duplicate-cu executable included in this
test-case, we run into:
...
(gdb) file debug-names-duplicate-cu^M
Reading symbols from debug-names-duplicate-cu...^M
src/gdb/dwarf2/read.c:2353: internal-error: read_addrmap_from_aranges: \
Assertion `insertpair.second' failed.^M
...
This assert was added in recent commit 75337cbc14 ("[gdb/symtab] Fix
.debug_aranges duplicate offset warning").
The assert triggers because the CU table in the .debug_names section contains
a duplicate:
...
Version 5
Augmentation string: 47 44 42 00 ("GDB")
CU table:
[ 0] 0x0
[ 1] 0x0
...
Fix this by rejecting the .debug_names index:
...
(gdb) file debug-names-duplicate-cu^M
Reading symbols from debug-names-duplicate-cu...^M
warning: Section .debug_names has duplicate entry in CU table, \
ignoring .debug_names.^M
...
Likewise for the case where the CU table is not sorted by increasing offset.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29436
In dwarf2_build_psymtabs_hard, we use a parallel_for_each to distribute CUs
over threads.
Ensuring a fair distribution over the worker threads and main thread in terms
of number of CUs might not be the most efficient way, given that CUs can vary
in size.
Fix this by using per_cu->get_length () as the task size.
I've used this experiment to verify the performance impact:
...
$ for n in $(seq 1 10); do \
time gdb -q -batch ~/firefox/libxul.so-93.0-1.1.x86_64.debug \
2>&1 \
| grep "real:"; \
done
...
and without the patch got:
...
real: 4.71
real: 4.88
real: 4.29
real: 4.30
real: 4.65
real: 4.27
real: 4.27
real: 4.27
real: 4.75
real: 4.41
...
and with the patch:
...
real: 3.68
real: 3.81
real: 3.80
real: 3.68
real: 3.75
real: 3.69
real: 3.69
real: 3.74
real: 3.67
real: 3.74
...
so that seems a reasonable improvement.
With parallel_for_each_debug set to true, we get some more detail about
the difference in behaviour. Without the patch we have:
...
Parallel for: n_elements: 2818
Parallel for: minimum elements per thread: 1
Parallel for: elts_per_thread: 704
Parallel for: elements on worker thread 0 : 705
Parallel for: elements on worker thread 1 : 705
Parallel for: elements on worker thread 2 : 704
Parallel for: elements on worker thread 3 : 0
Parallel for: elements on main thread : 704
...
and with the patch:
...
Parallel for: n_elements: 2818
Parallel for: total_size: 1483674865
Parallel for: size_per_thread: 370918716
Parallel for: elements on worker thread 0 : 752 (size: 371811790)
Parallel for: elements on worker thread 1 : 360 (size: 371509370)
Parallel for: elements on worker thread 2 : 1130 (size: 372681710)
Parallel for: elements on worker thread 3 : 0 (size: 0)
Parallel for: elements on main thread : 576 (size: 367671995)
...
Tested on x86_64-linux.
This changes struct objfile to use a gdb_bfd_ref_ptr. In addition to
removing some manual memory management, this fixes a use-after-free
that was introduced by the registry rewrite series. The issue there
was that, in some cases, registry shutdown could refer to memory that
had already been freed. This help fix the bug by delaying the
destruction of the BFD reference (and thus the per-bfd object) until
after the registry has been shut down.
The function read_addrmap_from_aranges contains code to issue a warning:
...
if (!insertpair.second)
{
warning (_("Section .debug_aranges in %s has duplicate "
"debug_info_offset %s, ignoring .debug_aranges."),
objfile_name (objfile), sect_offset_str (per_cu->sect_off));
return false;
}
...
but the warning is in fact activated when all_comp_units has duplicate
entries, which is very misleading.
Fix this by:
- adding a test-case that should trigger the warning,
- replacing the current implementation of the warning with an
assert that all_comp_units should not contain duplicates, and
- properly re-implementing the warning, such that it is triggered
by the test-case.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29381
Printing macros defined in the main source file doesn't work reliably
using various toolchains, especially when DWARF 5 is used. For example,
using the binaries produced by either of these commands:
$ gcc --version
gcc (GCC) 11.2.0
$ ld --version
GNU ld (GNU Binutils) 2.38
$ gcc test.c -g3 -gdwarf-5
$ clang --version
clang version 13.0.1
$ clang test.c -gdwarf-5 -fdebug-macro
I get:
$ ./gdb -nx -q --data-directory=data-directory a.out
(gdb) start
Temporary breakpoint 1 at 0x111d: file test.c, line 6.
Starting program: /home/simark/build/binutils-gdb-one-target/gdb/a.out
Temporary breakpoint 1, main () at test.c:6
6 return ZERO;
(gdb) p ZERO
No symbol "ZERO" in current context.
When starting to investigate this (taking the gcc-compiled binary as an
example), we see that GDB fails to look up the appropriate macro scope
when evaluating the expression. While stopped in
macro_lookup_inclusion:
(top-gdb) p name
$1 = 0x62100011a980 "test.c"
(top-gdb) p source.filename
$2 = 0x62100011a9a0 "/home/simark/build/binutils-gdb-one-target/gdb/test.c"
`source` is the macro_source_file that we would expect GDB to find.
`name` comes from the symtab::filename field of the symtab we are
stopped in. GDB doesn't find the appropriate macro_source_file because
the name of the macro_source_file doesn't match exactly the name of the
symtab.
The name of the main symtab comes from the compilation unit's
DW_AT_name, passed to the buildsym_compunit's constructor:
4815d6125e/gdb/dwarf2/read.c (L10627-10630)
The contents of DW_AT_name, in this case, is "test.c". It is typically
(what I witnessed all compilers do) the same string that was passed to
the compiler on the command-line.
The name of the macro_source_file comes from the line number program
header's file table, from the call to the line_header::file_file_name
method:
4815d6125e/gdb/dwarf2/macro.c (L54-65)
line_header::file_file_name prepends the directory path that the file
entry refers to, in the file table (if the file name is not already
absolute). In this case, the file name is "test.c", appended to the
directory "/home/simark/build/binutils-gdb-one-target/gdb".
Because the symtab's name is not created the same way as the
macro_source_file's name is created, we get this mismatch. GDB fails to
find the appropriate macro scope for the symtab, and we can't print
macros when stopped in that symtab.
To make this work, we must ensure that paths produced in these two ways
end up identical. This can be tricky because of the different ways a
path can be passed to the compiler by the user.
Another thing to consider is that while the main symtab's name (or
subfile, before it becomes a symtab) is created using DW_AT_name, the
main symtab is also referred to using its entry in the line table
header's file table, when processing the line table. We must therefore
ensure that the same name is produced in both cases, so that a call to
"start_subfile" for the main subfile will correctly find the
already-created subfile, created by buildsym_compunit's constructor. If
we fail to do that, things still often work, because of a fallback: the
watch_main_source_file_lossage method. This method determines that if
the main subfile has no symbols but there exists another subfile with
the same basename (e.g. "test.c") that does have symbols, it's probably
because there was some filename mismatch. So it replaces the main
subfile with that other subfile. I think that heuristic is useful as a
last effort to work around any bug or bad debug info, but I don't think
we should design things such as to rely on it. It's a heuristic, it can
get things wrong. So in my search for a fix, it is important that given
some good debug info, we don't end up relying on that for things to
work.
A first attempt at fixing this was to try to prepend the compilation
directory here or not prepend it there. In practice, because of all the
possible combinations of debug info the compilers produce, it was not
possible to get something that would produce reliable, consistent paths.
Another attempt at fixing this was to make both macro_source_file
objects and symtab objects use the most complete form of path possible.
That means to prepend directories at least until we get an absolute
path. In theory, we should end up with the same path in all cases.
This generally worked, but because it changed the symtab names, it
resulted in user-visible changes (for example, paths to source files in
Breakpoint hit messages becoming always absolute). I didn't find this
very good, first because there is a "set filename-display" setting that
lets the user control how they want the paths to be displayed, and that
would suddenly make this setting completely ineffective (although even
today, it is a bit dependent on the debug info). Second, it would
require a good amount of testsuite tweaks to make tests accept these
suddenly absolute paths.
This new patch is a slight variation of that: it adds a new field called
"filename_for_id" in struct symtab and struct subfile, next to the
existing filename field. The goal is to separate the internal ids used
for finding objects from the names used for presentation. This field is
used for identifying subfiles, symtabs and macro_source_files
internally. For DWARF symtabs, this new field is meant to contain the
"most complete possible" path, as discussed above. So for a given file,
it must always be in the same form, everywhere. The existing
symtab::filename field remains the one used for printing to the user, so
there shouldn't be any change in how paths are printed.
Changes in the core symtab files are:
- Add "name_for_id" and "filename_for_id" fields to "struct subfile"
and "struct symtab", next to existing "name" and "filename" fields.
- Make buildsym_compunit::buildsym_compunit and
buildsym_compunit::start_subfile accept a "name_for_id" parameter
next to the existing "name" ones.
- Make buildsym_compunit::start_subfile use "name_for_id" for looking
up existing subfiles. This is the key thing for making calls
to start_subfile for the main source file look up the existing
subfile successfully, and avoid relying on
watch_main_source_file_lossage.
- Make sal_macro_scope pass "filename_for_id", rather than "filename",
to macro_lookup_inclusion. This is the key thing to making the
lookup work and macro printing work.
Changes in the DWARF files are:
- Make line_header::file_file_name return the "most complete possible"
name. The only pre-existing user of this method is the macro code,
to give the macro_source_file objects their name. And we now want
them to have this "most complete possible" name, which will match the
corresponding symtab's "filename_for_id".
- Make dwarf2_cu::start_compunit_symtab pass the "most complete
possible" name for the main symtab's "filename_for_id". In this
context, where the info comes from the compilation unit's DW_AT_name
/ DW_AT_comp_dir, it means prepending DW_AT_comp_dir to DW_AT_name if
DW_AT_name is not already absolute.
- Change dwarf2_start_subfile to build a name_for_id for the subfile
being started. The simplest way is to re-use
line_header::file_file_name, since the callers always have a
file_entry handy. This ensures that it will get the exact same path
representation as the macro code does, for the same file (since it
also uses line_header::file_file_name).
- Update calls to allocate_symtab to pass the "name_for_id" from the
subfile.
Tests exercising all this are added by the following patch.
Of all the cases I tried, the only one I found that ends up relying on
watch_main_source_file_lossage is the following one:
$ clang --version
clang version 13.0.1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ clang ./test.c -g3 -O0 -gdwarf-4
$ ./gdb -nx --data-directory=data-directory -q -readnow -iex "set debug symtab-create 1" a.out
...
[symtab-create] start_subfile: name = test.c, name_for_id = /home/simark/build/binutils-gdb-one-target/gdb/test.c
[symtab-create] start_subfile: name = ./test.c, name_for_id = /home/simark/build/binutils-gdb-one-target/gdb/./test.c
[symtab-create] start_subfile: name = ./test.c, name_for_id = /home/simark/build/binutils-gdb-one-target/gdb/./test.c
[symtab-create] start_subfile: found existing symtab with name_for_id /home/simark/build/binutils-gdb-one-target/gdb/./test.c (/home/simark/build/binutils-gdb-one-target/gdb/./test.c)
[symtab-create] watch_main_source_file_lossage: using subfile ./test.c as the main subfile
As we can see, there are two forms used for "test.c", one with a "." and
one without. This comes from the fact that the compilation unit DIE
contains:
DW_AT_name ("test.c")
DW_AT_comp_dir ("/home/simark/build/binutils-gdb-one-target/gdb")
without a ".", and the line table for that file contains:
include_directories[ 1] = "."
file_names[ 1]:
name: "test.c"
dir_index: 1
When assembling the filename from that entry, we get a ".".
It is a bit unexpected that the main filename resulting from the line
table header does not match exactly the name in the compilation unit.
For instance, gcc uses "./test.c" for the DW_AT_name, which gives
identical paths in the compilation unit and in the line table header.
Similarly, with DWARF 5:
$ clang ./test.c -g3 -O0 -gdwarf-5
clang create two entries that refer to the same file but are of in a different
form.
include_directories[ 0] = "/home/simark/build/binutils-gdb-one-target/gdb"
include_directories[ 1] = "."
file_names[ 0]:
name: "test.c"
dir_index: 0
file_names[ 1]:
name: "test.c"
dir_index: 1
The first file name produces a path without a "." while the second does.
This is not caught by watch_main_source_file_lossage, because of
dwarf_decode_lines that creates a symtab for each file entry in the line
table. It therefore appears as "non-empty" to
watch_main_source_file_lossage. This results in two symtabs:
(gdb) maintenance info symtabs
{ objfile /home/simark/build/binutils-gdb-one-target/gdb/a.out ((struct objfile *) 0x613000005d00)
{ ((struct compunit_symtab *) 0x62100011aca0)
debugformat DWARF 5
producer clang version 13.0.1
name test.c
dirname /home/simark/build/binutils-gdb-one-target/gdb
blockvector ((struct blockvector *) 0x621000129ec0)
user ((struct compunit_symtab *) (null))
{ symtab test.c ((struct symtab *) 0x62100011ad20)
fullname (null)
linetable ((struct linetable *) 0x0)
}
{ symtab ./test.c ((struct symtab *) 0x62100011ad60)
fullname (null)
linetable ((struct linetable *) 0x621000129ef0)
}
}
}
I am not sure what is the consequence of this, but this is also what
happens before my patch, so I think its acceptable to leave it as-is.
To handle these two cases nicely, I think we will need a function that
removes the unnecessary "." from path names, something that can be done
later.
Finally, I made a change in find_file_and_directory is necessary to
avoid breaking test
gdb.dwarf2/dw2-compdir-oldgcc.exp: info source gcc42
Without that change, we would get:
(gdb) info source
Current source file is /dir/d/dw2-compdir-oldgcc42.S
Compilation directory is /dir/d
whereas the expected result is:
(gdb) info source
Current source file is dw2-compdir-oldgcc42.S
Compilation directory is /dir/d
This test was added here:
https://sourceware.org/pipermail/gdb-patches/2012-November/098144.html
Long story short, GCC <= 4.2 apparently had a bug where it would
generate a DW_AT_name with a full path ("/dir/d/dw2-compdir-oldgcc42.S")
and no DW_AT_comp_dir. The line table has one entry with filename
"dw2-compdir-oldgcc42.S", which refers to directory 0. Directory 0
normally refers to the compilation unit's comp dir, but it is
non-existent in this case.
This caused some symtab lookup problems, and to work around them, some
workaround was added, which today reads as:
if (res.get_comp_dir () == nullptr
&& producer_is_gcc_lt_4_3 (cu)
&& res.get_name () != nullptr
&& IS_ABSOLUTE_PATH (res.get_name ()))
res.set_comp_dir (ldirname (res.get_name ()));
Source: 6577f365eb/gdb/dwarf2/read.c (L9428-9432)
It extracts an artificial DW_AT_comp_dir from DW_AT_name, if there is no
DW_AT_comp_dir and DW_AT_name is absolute.
Prior to my patch, a subfile would get created with filename
"/dir/d/dw2-compdir-oldgcc42.S", from DW_AT_name, and another would get
created with filename "dw2-compdir-oldgcc42.S" from the line table's
file table. Then watch_main_source_file_lossage would kick in and merge
them, keeping only the "dw2-compdir-oldgcc42.S" one:
[symtab-create] start_subfile: name = /dir/d/dw2-compdir-oldgcc42.S
[symtab-create] start_subfile: name = dw2-compdir-oldgcc42.S
[symtab-create] start_subfile: name = dw2-compdir-oldgcc42.S
[symtab-create] start_subfile: found existing symtab with name dw2-compdir-oldgcc42.S (dw2-compdir-oldgcc42.S)
[symtab-create] watch_main_source_file_lossage: using subfile dw2-compdir-oldgcc42.S as the main subfile
And so "info source" would show "dw2-compdir-oldgcc42.S" as the
filename.
With my patch applied, but without the change in
find_file_and_directory, both DW_AT_name and the line table would try to
start a subfile with the same filename_for_id, and there was no need for
watch_main_source_file_lossage - which is what we want:
[symtab-create] start_subfile: name = /dir/d/dw2-compdir-oldgcc42.S, name_for_id = /dir/d/dw2-compdir-oldgcc42.S
[symtab-create] start_subfile: name = dw2-compdir-oldgcc42.S, name_for_id = /dir/d/dw2-compdir-oldgcc42.S
[symtab-create] start_subfile: found existing symtab with name_for_id /dir/d/dw2-compdir-oldgcc42.S (/dir/d/dw2-compdir-oldgcc42.S)
[symtab-create] start_subfile: name = dw2-compdir-oldgcc42.S, name_for_id = /dir/d/dw2-compdir-oldgcc42.S
[symtab-create] start_subfile: found existing symtab with name_for_id /dir/d/dw2-compdir-oldgcc42.S (/dir/d/dw2-compdir-oldgcc42.S)
But since the one with name == "/dir/d/dw2-compdir-oldgcc42.S", coming
from DW_AT_name, gets created first, it wins, and the symtab ends up
with "/dir/d/dw2-compdir-oldgcc42.S" as the name, "info source" shows
"/dir/d/dw2-compdir-oldgcc42.S" and the test breaks.
This is not wrong per-se, after all DW_AT_name is
"/dir/d/dw2-compdir-oldgcc42.S", so it wouldn't be wrong to report the
current source file as "/dir/d/dw2-compdir-oldgcc42.S". If you compile
a file passing "/an/absolute/path.c", DW_AT_name typically contains (at
least with GCC) "/an/absolute/path.c" and GDB tells you that the source
file is "/an/absolute/path.c". But we can also keep the existing
behavior fairly easily with a little change in find_file_and_directory.
When extracting an artificial DW_AT_comp_dir from DW_AT_name, we now
modify the name to just keep the file part. The result is coherent with
what compilers do when you compile a file by just passing its filename
("gcc path.c -g"):
DW_AT_name ("path.c")
DW_AT_comp_dir ("/home/simark/build/binutils-gdb-one-target/gdb")
With this change, filename_for_id is still the full name,
"/dir/d/dw2-compdir-oldgcc42.S", but the filename of the subfile /
symtab (what ends up shown by "info source") is just
"dw2-compdir-oldgcc42.S", and that makes the test happy.
Change-Id: I8b5cc4bb3052afdb172ee815c051187290566307
The following patch changes line_header::file_file_name to prepend the
compilation directory to the file name, if needed. For that, the line
header needs to know about the compilation directory. Prepare for that
by adding a constructor that takes it as a parameter, and passing the
value down everywhere needed. Add a second constructor for the special
case of building a line_header for doing a hash table lookup, since that
case doesn't require a compilation directory value.
Change-Id: Iba3ba0293e4e2d13a64b257cf9a3094684d54330
This rewrites registry.h, removing all the macros and replacing it
with relatively ordinary template classes. The result is less code
than the previous setup. It replaces large macros with a relatively
straightforward C++ class, and now manages its own cleanup.
The existing type-safe "key" class is replaced with the equivalent
template class. This approach ended up requiring relatively few
changes to the users of the registry code in gdb -- code using the key
system just required a small change to the key's declaration.
All existing users of the old C-like API are now converted to use the
type-safe API. This mostly involved changing explicit deletion
functions to be an operator() in a deleter class.
The old "save/free" two-phase process is removed, and replaced with a
single "free" phase. No existing code used both phases.
The old "free" callbacks took a parameter for the enclosing container
object. However, this wasn't truly needed and is removed here as
well.
When running test-case gdb.cp/cpexprs-debug-types.exp with target board
cc-with-debug-names on a system with gcc 12.1.1 (defaulting to dwarf 5), I
run into:
...
(gdb) file cpexprs-debug-types^M
Reading symbols from cpexprs-debug-types...^M
warning: Section .debug_aranges in cpexprs-debug-types has duplicate \
debug_info_offset 0x0, ignoring .debug_aranges.^M
gdb/dwarf2/read.h:309: internal-error: set_length: \
Assertion `m_length == length' failed.^M
...
The exec contains a .debug_names section, which gdb rejects due to
.debug_names containing a list of TUs, while the exec doesn't contain a
.debug_types section (which is what you'd expect for dwarf 4).
Gdb then falls back onto the cooked index, which calls create_all_comp_units
to create all_comp_units. However, the failed index reading left some
elements in all_comp_units, so we end up with duplicates in all_comp_units,
which causes the misleading complaint and the assert.
Fix this by:
- asserting at the start of create_all_comp_units that all_comp_units is empty,
as we do in create_cus_from_index and create_cus_from_debug_names, and
- cleaning up all_comp_units when failing in dwarf2_read_debug_names.
Add a similar cleanup in dwarf2_read_gdb_index.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29381
I noticed this code in dw2_debug_names_iterator::next:
...
case DW_IDX_compile_unit:
/* Don't crash on bad data. */
if (ull >= per_bfd->all_comp_units.size ())
{
complaint (_(".debug_names entry has bad CU index %s"
" [in module %s]"),
pulongest (ull),
objfile_name (objfile));
continue;
}
per_cu = per_bfd->get_cu (ull);
break;
...
This code used to DTRT, before we started keeping both CUs and TUs in
all_comp_units.
Fix by using "per_bfd->all_comp_units.size () - per_bfd->tu_stats.nr_tus"
instead.
It's hard to produce a test-case for this, but let's try at least to trigger
the complaint somehow. We start out by creating an exec with .debug_types and
.debug_names:
...
$ gcc -g ~/hello.c -fdebug-types-section
$ gdb-add-index -dwarf-5 a.out
...
and verify that we don't see any complaints:
...
$ gdb -q -batch -iex "set complaints 100" ./a.out
...
We look at the CU and TU table using readelf -w and conclude that we have
nr_cus == 6 and nr_tus == 1.
Now override ull in dw2_debug_names_iterator::next for the DW_IDX_compile_unit
case to 6, and we have:
...
$ gdb -q -batch -iex "set complaints 100" ./a.out
During symbol reading: .debug_names entry has bad CU index 6 [in module a.out]
...
After this, it still crashes because this code in
dw2_debug_names_iterator::next:
...
/* Skip if already read in. */
if (m_per_objfile->symtab_set_p (per_cu))
goto again;
...
is called with per_cu == nullptr.
Fix this by skipping the entry if per_cu == nullptr.
Now revert the fix and observe that the complaint disappears, so we've
confirmed that the fix is required.
A somewhat similar issue for .gdb_index in dw2_symtab_iter_next has been filed
as PR29367.
Tested on x86_64-linux, with native and target board cc-with-debug-names.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29336
When building gdb with -fsanitize-threads and running test-case
gdb.ada/char_enum_unicode.exp, I run into:
...
WARNING: ThreadSanitizer: data race (pid=21301)^M
Write of size 8 at 0x7b2000008080 by main thread:^M
#0 free <null> (libtsan.so.2+0x4c5e2)^M
#1 _dl_close_worker <null> (ld-linux-x86-64.so.2+0x4b7b)^M
#2 convert_between_encodings() charset.c:584^M
...
#21 cooked_index_functions::expand_symtabs_matching() read.c:18606
...
This is fixed by making cooked_index_functions::expand_symtabs_matching wait
for the cooked index finalization to be done.
Tested on x86_64-linux.
https://sourceware.org/bugzilla/show_bug.cgi?id=29311https://sourceware.org/bugzilla/show_bug.cgi?id=29286
We have in per_cu->set_lang this comment:
...
void set_lang (enum language lang)
{
/* We'd like to be more strict here, similar to what is done in
set_unit_type, but currently a partial unit can go from unknown to
minimal to ada to c. */
...
Fix this by not setting m_lang for partial units.
This requires us to move the m_unit_type initialization to ensure that
m_unit_type is initialized before per_cu->m_lang.
Tested on x86_64-linux, with native and target board cc-with-dwz-m.
The cu->per_cu->lang field was added to carry information from the initial
partial symtabs phase to the symtab expansion phase, for the benefit of a
particular optimization in process_imported_unit_die.
Other uses have been added, but since the first phase now has been
parallelized, those have become problematic and sources of race conditions.
Fix this by adding dwarf2_cu::lang () and using it where we can to replace
cu->per_cu->lang () with cu->lang ().
Also assert in dwarf2_cu::lang () that we're not returning language_unknown.
Tested on x86_64-linux.
