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2024-09-27gdb/symtab: pass program space to lookup_symtab and iterate_over_symtabsSimon Marchi1-4/+10
Make the current program space references bubble up. In collect_symtabs_from_filename, remove the calls to set_current_program_space and just pass the relevant pspaces. This appears safe to do, because nothing in the `collector` callback cares about the current pspace. Change-Id: I00a7ed484bfbe5264f01a6abf0d33b51de373cbb Reviewed-by: Keith Seitz <keiths@redhat.com>
2024-09-20gdb: Move dbx_end_psymtab to stabsread, and rename to stabs_end_psymtabGuinevere Larsen1-1/+1
This function is used by multiple stabs readers (even if not all), and the comment in stabsread.h even acknowledges it. I believe that the comment is incorrect in saying that the function should be in dbxread because not everyone uses it. If any one reader other than dbx uses it, the function should be in stabsread, in my opinion. This commit makes also renames the function to stabs_end_psymtab since, again, this is not specific to dbx/aout format. struct symloc had to be moved because stabs_end_psymtab dereferences symloc objects, so stabsread.c must be aware of the full struct. Approved-By: Tom Tromey <tom@tromey.com>
2024-09-12gdb: change type of `general_symbol_info::m_section` to intSimon Marchi1-3/+3
The binary provided with bug 32165 [1] has 36139 ELF sections. GDB crashes on it with (note that my GDB is build with -D_GLIBCXX_DEBUG=1: $ ./gdb -nx -q --data-directory=data-directory ./vmlinux Reading symbols from ./vmlinux... (No debugging symbols found in ./vmlinux) (gdb) info func /usr/include/c++/14.2.1/debug/vector:508: In function: std::debug::vector<_Tp, _Allocator>::reference std::debug::vector<_Tp, _Allocator>::operator[](size_type) [with _Tp = long unsigned int; _Allocator = std::allocator<long unsigned int>; reference = long unsigned int&; size_type = long unsigned int] Error: attempt to subscript container with out-of-bounds index -29445, but container only holds 36110 elements. Objects involved in the operation: sequence "this" @ 0x514000007340 { type = std::debug::vector<unsigned long, std::allocator<unsigned long> >; } The crash occurs here: #3 0x00007ffff5e334c3 in __GI_abort () at abort.c:79 #4 0x00007ffff689afc4 in __gnu_debug::_Error_formatter::_M_error (this=<optimized out>) at /usr/src/debug/gcc/gcc/libstdc++-v3/src/c++11/debug.cc:1320 #5 0x0000555561119a16 in std::__debug::vector<unsigned long, std::allocator<unsigned long> >::operator[] (this=0x514000007340, __n=18446744073709522171) at /usr/include/c++/14.2.1/debug/vector:508 #6 0x0000555562e288e8 in minimal_symbol::value_address (this=0x5190000bb698, objfile=0x514000007240) at /home/smarchi/src/binutils-gdb/gdb/symtab.c:517 #7 0x0000555562e5a131 in global_symbol_searcher::expand_symtabs (this=0x7ffff0f5c340, objfile=0x514000007240, preg=std::optional [no contained value]) at /home/smarchi/src/binutils-gdb/gdb/symtab.c:4983 #8 0x0000555562e5d2ed in global_symbol_searcher::search (this=0x7ffff0f5c340) at /home/smarchi/src/binutils-gdb/gdb/symtab.c:5189 #9 0x0000555562e5ffa4 in symtab_symbol_info (quiet=false, exclude_minsyms=false, regexp=0x0, kind=FUNCTION_DOMAIN, t_regexp=0x0, from_tty=1) at /home/smarchi/src/binutils-gdb/gdb/symtab.c:5361 #10 0x0000555562e6131b in info_functions_command (args=0x0, from_tty=1) at /home/smarchi/src/binutils-gdb/gdb/symtab.c:5525 That is, at this line of `minimal_symbol::value_address`, where `objfile->section_offsets` is an `std::vector`: return (CORE_ADDR (this->unrelocated_address ()) + objfile->section_offsets[this->section_index ()]); A section index of -29445 is suspicious. The minimal_symbol at play here is: (top-gdb) p m_name $1 = 0x521001de10af "_sinittext" So I restarted debugging, breaking on: (top-gdb) b general_symbol_info::set_section_index if $_streq("_sinittext", m_name) And I see that weird -29445 value: (top-gdb) frame #0 general_symbol_info::set_section_index (this=0x525000082390, idx=-29445) at /home/smarchi/src/binutils-gdb/gdb/symtab.h:611 611 { m_section = idx; } But going up one frame, the section index is 36091: (top-gdb) frame #1 0x0000555562426526 in minimal_symbol_reader::record_full (this=0x7ffff0ead560, name="_sinittext", copy_name=false, address=-2111475712, ms_type=mst_text, section=36091) at /home/smarchi/src/binutils-gdb/gdb/minsyms.c:1228 1228 msymbol->set_section_index (section); It seems like the problem is just that the type used for the section index (short) is not big enough. Change from short to int. If somebody insists, we could even go long long / int64_t, but I doubt it's necessary. With that fixed, I get: (gdb) info func All defined functions: Non-debugging symbols: 0xffffffff81000000 _stext 0xffffffff82257000 _sinittext 0xffffffff822b4ebb _einittext [1] https://sourceware.org/bugzilla/show_bug.cgi?id=32165 Change-Id: Icb1c3de9474ff5adef7e0bbbf5e0b67b279dee04 Reviewed-By: Tom de Vries <tdevries@suse.de> Reviewed-by: Keith Seitz <keiths@redhat.com>
2024-09-06Fix 'catch exception' with -fltoTom Tromey1-11/+1
A user noticed that when an Ada program (including the runtime) is compiled with -flto, then "catch exception" does not work -- even though setting the equivalent breakpoint by hand does work. Looking into this, it turns out that GCC puts the exception functions from the Ada runtime into a CU that uses the C language, not Ada. Then, when trying to look up the relevant symbol, lookup_name_info::search_name_hash uses the "verbatim" form of the symbol name (like "<__gnat_debug_raise_exception>") rather than the "<>"-less form, causing the symbol not to be found. This patch fixes the problem in two steps. First, lookup_name_info::search_name_hash is changed to use the same hack that language_defn::get_symbol_name_matcher uses. That is, when the current language is Ada, verbatim-mode lookups are special-cased. (This is a bit unfortunate; perhaps a better long term approach would be to promote verbatim mode to a fundamental mode of lookup_name_info.) Second, although the above fixes the problem in the Ada language mode, the code still fails in other languages. However, due to the way these lookups are coded in ada-lang.c, I think it makes sense to temporarily set the current language to Ada in create_ada_exception_catchpoint. Tested on x86-64 Fedora 38. A new test case that mimics the -flto scenario is included. Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>
2024-08-12gdb: drop struct keyword when using bound_minimal_symbolSimon Marchi1-1/+1
This is a simple find / replace from "struct bound_minimal_symbol" to "bound_minimal_symbol", to make things shorter and more consisten througout. In some cases, move variable declarations where first used. Change-Id: Ica4af11c4ac528aa842bfa49a7afe8fe77a66849 Reviewed-by: Keith Seitz <keiths@redhat.com> Approved-By: Andrew Burgess <aburgess@redhat.com>
2024-06-24Don't obstack-allocate the call site hash tableTom Tromey1-1/+7
The call site hash table is the last hash table using obstack allocation. In one large (non-public) test case, these hash tables take a substiantial amount of memory. Some of this memory is wasted -- whenever the hash table is resized, the old table is not freed. This patch fixes the problem by changing this hash table to be heap-allocated. This means that resizing will no longer "leak" memory.
2024-06-24Add compunit_symtab::forget_cached_source_infoTom Tromey1-0/+3
It seemed cleaner to me for compunit_symtab to have a forget_cached_source_info method, then for the objfile to know how to do this.
2024-06-24Make symtab members privateTom Tromey1-9/+11
This rearranges symtab so that the private members appear at the end, and then adds the "private" keyword.
2024-06-24Rename symtab::fullnameTom Tromey1-1/+22
This renames symtab::fullname to m_fullname and adds new accessor methods.
2024-06-14Move search_symbol_list to symtab.cTom Tromey1-0/+7
This moves search_symbol_list to symtab.c and exports it. It will be useful in a later patch.
2024-06-14Rename is_cplus_template_functionTom Tromey1-2/+6
This patch renames is_cplus_template_function to is_template_function. There is nothing C++-specific about this code, and the code in the DWARF reader that creates these objects is not C++-specific. In fact this may already be used by Rust (though I didn't check).
2024-06-10Make global_symbol_searcher::filenames privateTom Tromey1-4/+6
This patch renames global_symbol_searcher::filenames and makes it private, adding a new method to append a filename to the vector. This also cleans up memory management here, removing an alloca from rbreak, and removing a somewhat ugly SCOPE_EXIT from the Python code, in favor of having global_symbol_searcher manage the memory itself. Regression tested on x86-64 Fedora 38.
2024-03-21Require trivial destructor in allocate_on_obstackTom Tromey1-1/+1
This patch makes allocate_on_obstack a little bit safer, by enforcing the rule that objects allocated on an obstack must have a trivial destructor. The static assert is done in a method -- doing it inside the class itself won't work because the class is incomplete at that point.
2024-03-19Speed up lookup of "type_specific_data"Tom Tromey1-2/+4
I noticed that "info locals" on a certain large Ada program was very slow. I tracked this down to ada_get_tsd_type expanding nearly every CU in the program. This patch fixes the problem by changing this code to use the more efficient lookup_transparent_type which, unlike the Ada-specific lookup functions, does not try to find all matching instances. Note that I first tried fixing this by changing ada_find_any_type, but this did not work -- I may revisit this approach at some later date. Also note that the copyright dates on the test files are set that way because I copied them from another test. New in v2: the new test failed on the Linaro regression tester. Looking at the logs, it seems that gdb was picking up a 'value' from libgnat: $1 = {<text variable, no debug info>} 0xf7e227a4 <ada.calendar.formatting.value> This version renames the local variable in an attempt to work around this. v3: In v2, while trying to reproduce the problem locally, I accidentally forgot to commit one of the changes.
2024-02-20gdb: pass frames as `const frame_info_ptr &`Simon Marchi1-4/+4
We currently pass frames to function by value, as `frame_info_ptr`. This is somewhat expensive: - the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass by value - the constructors and destructor link/unlink the object in the global `frame_info_ptr::frame_list` list. This is an `intrusive_list`, so it's not so bad: it's just assigning a few points, there's no memory allocation as if it was `std::list`, but still it's useless to do that over and over. As suggested by Tom Tromey, change many function signatures to accept `const frame_info_ptr &` instead of `frame_info_ptr`. Some functions reassign their `frame_info_ptr` parameter, like: void the_func (frame_info_ptr frame) { for (; frame != nullptr; frame = get_prev_frame (frame)) { ... } } I wondered what to do about them, do I leave them as-is or change them (and need to introduce a separate local variable that can be re-assigned). I opted for the later for consistency. It might not be clear why some functions take `const frame_info_ptr &` while others take `frame_info_ptr`. Also, if a function took a `frame_info_ptr` because it did re-assign its parameter, I doubt that we would think to change it to `const frame_info_ptr &` should the implementation change such that it doesn't need to take `frame_info_ptr` anymore. It seems better to have a simple rule and apply it everywhere. Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0 Approved-By: Andrew Burgess <aburgess@redhat.com>
2024-02-09gdb: add program_space parameter to clear_solibSimon Marchi1-4/+0
Make the current_program_space reference bubble up one level. Remove one unnecessary declaration of clear_solib. Change-Id: I234e2c8c0b71713364fc7b76cee2bee2b026bd6d Approved-By: Andrew Burgess <aburgess@redhat.com>
2024-02-01Rename SEARCH_ALLTom Tromey1-2/+2
The constant SEARCH_ALL conflicts with a define in a Windows header. This patch renames the constant to SEARCH_ALL_DOMAINS to avoid the conflict. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31307
2024-01-29gdb: Use SYM_DOMAIN instead of DOMAIN when calling sym-domains.defLancelot SIX1-6/+6
Since commit 6771fc6f1d9 "Use a .def file for domain_enum", the sym-domains.def file has been introduced, and requires the user to define the DOMAIN(x) macro. On older systems (centos-7 with glibc-2.17 for example), this DOMAIN macro conflicts with another macro defined in /usr/include/math.h. Fix this conflict by changing sym-domains.def to use a macro named SYM_DOMAIN instead of DOMAIN. Change-Id: I679df30e2bd2f4333343f16bbd2a3511a37550a3 Approved-By: Tom Tromey <tom@tromey.com>
2024-01-28Remove old symbol_matches_domainTom Tromey1-11/+0
Nothing calls the variant of symbol_matches_domain that accepts a domain_enum for searching, so this patch removes it and the corresponding symbol::matches.
2024-01-28Use domain_search_flags in lookup_symbol et alTom Tromey1-11/+12
This changes lookup_symbol and associated APIs to accept domain_search_flags rather than a domain_enum. Note that this introduces some new constants to Python and Guile. I chose to break out the documentation patch for this, because the internals here do not change until a later patch, and it seemed simpler to patch the docs just once, rather than twice.
2024-01-28Use domain_search_flags in lookup_global_symbol_languageTom Tromey1-2/+2
This changes quick_symbol_functions::lookup_global_symbol_language to accept domain_search_flags rather than just a domain_enum, and fixes up the fallout. To avoid introducing any regressions, any code passing VAR_DOMAIN now uses SEARCH_VFT. That is, no visible changes should result from this patch. However, it sets the stage to refine some searches later on.
2024-01-28Introduce "scripting" domainsTom Tromey1-0/+31
The Python and Guile code exposed the internal domain constants both as attributes of symbols and as values to pass to lookup functions. Now, perfect backward compatibility here can't be achieved: some symbols are going to have domain changes by the end of this series. However, it seemed to me that we can preserve lookups using the basic domain values. This patch implements this by exporting the "or"-able search constants with an extra bit set. Then it introduces some functions to convert such constants to domain_search_flags. This will be used by the Python and Guile code, so that both old- and new-style lookups will work properly; and while preserving the idea that the domain constants can be compared to a symbol's domain.
2024-01-28Replace search_domain with domain_search_flagsTom Tromey1-31/+5
This patch changes gdb to replace search_domain with domain_search_flags everywhere. search_domain is removed.
2024-01-28Add domain_search_flagsTom Tromey1-0/+45
This adds a new flag enum type, domain_search_flags, which is the flag version of domain_enum. Nothing uses this yet, but the goal here is to have all symbol searches and lookups use these flags. The new names are chosen to exactly parallel domain_enum.
2024-01-28Use a .def file for domain_enumTom Tromey1-28/+3
Future patches will change and reuse the names from domain_enum. This patch makes this less error-prone by having a single point to define these names, using the typical gdb ".def" file.
2024-01-28Simplify symbol_to_info_stringTom Tromey1-4/+2
Thi simplifies symbol_to_info_string, removing the 'kind' parameter and instead having it use the symbol's domain.
2024-01-28Remove NR_DOMAINSTom Tromey1-4/+0
NR_DOMAINS is only used for a static assert, but we no longer need it now. If we add too many constants to this enum, GCC will warn about the bitfield overflow: error: ‘symbol::m_domain’ is too small to hold all values of ‘enum domain_enum’
2024-01-19gdb: remove SYMBOL_*_OPS macrosSimon Marchi1-6/+19
Remove SYMBOL_BLOCK_OPS, SYMBOL_COMPUTED_OPS and SYMBOL_REGISTER_OPS, in favor of methods on struct symbol. More changes could be done here to improve the design and make things safer, but I just wanted to do a straightforward change to remove the macros for now. Change-Id: I27adb74a28ea3c0dc9a85c2953413437cd95ad21 Reviewed-by: Kevin Buettner <kevinb@redhat.com>
2024-01-12Update copyright year range in header of all files managed by GDBAndrew Burgess1-1/+1
This commit is the result of the following actions: - Running gdb/copyright.py to update all of the copyright headers to include 2024, - Manually updating a few files the copyright.py script told me to update, these files had copyright headers embedded within the file, - Regenerating gdbsupport/Makefile.in to refresh it's copyright date, - Using grep to find other files that still mentioned 2023. If these files were updated last year from 2022 to 2023 then I've updated them this year to 2024. I'm sure I've probably missed some dates. Feel free to fix them up as you spot them.
2024-01-02PowerPC and aarch64: Fix reverse stepping failureCarl Love1-0/+17
When running GDB's testsuite on aarch64-linux/Ubuntu 20.04 (also spotted on the ppc backend), there are failures in gdb.reverse/solib-precsave.exp and gdb.reverse/solib-reverse.exp. The failure happens around the following code: 38 b[1] = shr2(17); /* middle part two */ 40 b[0] = 6; b[1] = 9; /* generic statement, end part two */ 42 shr1 ("message 1\n"); /* shr1 one */ Normal execution: - step from line 38 will land on line 40. - step from line 40 will land on line 42. Reverse execution: - step from line 42 will land on line 40. - step from line 40 will land on line 40. - step from line 40 will land on line 38. The problem here is that line 40 contains two contiguous but distinct PC ranges in the line table, like so: Line 40 - [0x7ec ~ 0x7f4] Line 40 - [0x7f4 ~ 0x7fc] The two distinct ranges are generated because GCC started outputting source column information, which GDB doesn't take into account at the moment. When stepping forward from line 40, we skip both of these ranges and land on line 42. When stepping backward from line 42, we stop at the start PC of the second (or first, going backwards) range of line 40. Since we've reached ecs->event_thread->control.step_range_start, we stop stepping backwards. The above issues were fixed by introducing a new function that looks for adjacent PC ranges for the same line, until we notice a line change. Then we take that as the start PC of the range. The new start PC for the range is used for the control.step_range_start when setting up a step range. The test case gdb.reverse/map-to-same-line.exp is added to test the fix for the above reverse step issues. Patch has been tested on PowerPC, X86 and AArch64 with no regressions.
2024-01-02gdb/dwarf2: Add support for DW_LNS_set_epilogue_begin in line-tableGuinevere Larsen1-0/+11
This commit adds a mechanism for GDB to detect the linetable opcode DW_LNS_set_epilogue_begin. This opcode is set by compilers to indicate that a certain instruction marks the point where the frame is destroyed. While the standard allows for multiple points marked with epilogue_begin in the same function, for performance reasons, the function that searches for the epilogue address will only find the last address that sets this flag for a given block. This commit also changes amd64_stack_frame_destroyed_p_1 to attempt to use the epilogue begin directly, and only if an epilogue can't be found will it attempt heuristics based on the current instruction. Finally, this commit also changes the dwarf assembler to be able to emit epilogue-begin instructions, to make it easier to test this patch Approved-By: Tom Tromey <tom@tromey.com>
2023-12-06Always use expand_symtabs_matching in ada-lang.cTom Tromey1-4/+9
The previous patch fixed the immediate performance problem with Ada name matching, by having a subset of matches call expand_symtabs_matching rather than expand_matching_symbols. However, it seemed to me that expand_matching_symbols should not be needed at all. To achieve this, this patch changes ada_lookup_name_info::split_name to use the decoded name, rather than the encoded name. In order to make this work correctly, a new decoded form is used: one that does not decode operators (this is already done) and also does not decode wide characters. The latter change is done so that changes to the Ada source charset don't affect the DWARF index. With this in place, we can change ada-lang.c to always use expand_symtabs_matching rather than expand_matching_symbols.
2023-11-29Remove gdb_static_assertTom Tromey1-3/+3
C++17 makes the second parameter to static_assert optional, so we can remove gdb_static_assert now.
2023-11-21gdb: Use std::string_view instead of gdb::string_viewLancelot Six1-7/+7
Given that GDB now requires a C++17, replace all uses of gdb::string_view with std::string_view. This change has mostly been done automatically: - gdb::string_view -> std::string_view - #include "gdbsupport/gdb_string_view.h" -> #include <string_view> One things which got brought up during review is that gdb::stging_view does support being built from "nullptr" while std::sting_view does not. Two places are manually adjusted to account for this difference: gdb/tui/tui-io.c:tui_getc_1 and gdbsupport/format.h:format_piece::format_piece. The above automatic change transformed "gdb::to_string (const gdb::string_view &)" into "gdb::to_string (const std::string_view &)". The various direct users of this function are now explicitly including "gdbsupport/gdb_string_view.h". A later patch will remove the users of gdb::to_string. The implementation and tests of gdb::string_view are unchanged, they will be removed in a following patch. Change-Id: Ibb806a7e9c79eb16a55c87c6e41ad396fecf0207 Approved-By: Tom Tromey <tom@tromey.com> Approved-By: Pedro Alves <pedro@palves.net>
2023-11-21gdb: Replace gdb::optional with std::optionalLancelot Six1-12/+12
Since GDB now requires C++17, we don't need the internally maintained gdb::optional implementation. This patch does the following replacing: - gdb::optional -> std::optional - gdb::in_place -> std::in_place - #include "gdbsupport/gdb_optional.h" -> #include <optional> This change has mostly been done automatically. One exception is gdbsupport/thread-pool.* which did not use the gdb:: prefix as it already lives in the gdb namespace. Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9 Approved-By: Tom Tromey <tom@tromey.com> Approved-By: Pedro Alves <pedro@palves.net>
2023-10-25gdb: make get_symbol_address a private method of symbolSimon Marchi1-9/+8
get_symbol_address is only used symbol::value_address, make it a private helper method. Change-Id: I318ddcfcf1269d95045b8efe9137812df9c5113c Approved-By: Tom Tromey <tom@tromey.com>
2023-10-25gdb: make get_msymbol_address a private method of minimal_symbolSimon Marchi1-9/+7
get_msymbol_address is only used in minimal_symbol::value_address. Make it a private helper method. Change-Id: I3f30e1b9d89ace6682fb08a7ebb91746db0ccf0f Approved-By: Tom Tromey <tom@tromey.com>
2023-09-18More type safety for symbol_searchTom Tromey1-5/+5
This patch changes class symbol_search to store a block_enum rather than an int. Regression tested on x86-64 Fedora 38. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-09-15Rename split_style::DOTTom Tromey1-1/+1
This renames split_style::DOT, to avoid name clashes when building gdb with an old version of Bison (2.3, the version available on macOS). In particular the error looks like: ./split-name.h:34:3: error: expected identifier DOT, ^ m2-exp.c:163:13: note: expanded from macro 'DOT' Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30286
2023-08-31Add symbol::matches methodTom Tromey1-4/+11
This adds symbol::matches, a wrapper for symbol_matches_domain. Most places calling symbol_matches_domain can call this method instead, which is a bit less wordy and also (IMO) clearer. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-08-31[symtab/27831] Fix OBJF_MAINLINE assertKevin Buettner1-8/+9
This commit fixes a bug mentioned by Florian Weimer during the libpthread/ld.so load order discussion from 2021. Florian provided instructions for reproducing the bug here: https://sourceware.org/pipermail/gdb-patches/2021-April/177923.html That particular test does some interesting things involving forks, threads, and thread local storage. Fortunately, none of that is needed to reproduce the problem. I've made a new test case (which is now found in a separate commit) contained in the files gdb.base/add-symbol-file-attach.{c,exp}. The .c file is fairly simple as is the recipe for reproducing the problem. After separately starting the test case and noting the process id, start gdb (w/ no arguments), and do the following to reproduce the assertion failure - for this run, the process id of the separately started add-symbol-file-attach process is 4103218: (gdb) add-symbol-file add-symbol-file-attach add symbol table from file "add-symbol-file-attach" (y or n) y Reading symbols from add-symbol-file-attach... (gdb) attach 4103218 Attaching to process 4103218 Load new symbol table from "/tmp/add-symbol-file-attach"? (y or n) y Reading symbols from /tmp/add-symbol-file-attach... Reading symbols from /lib64/libc.so.6... (No debugging symbols found in /lib64/libc.so.6) Reading symbols from /lib64/ld-linux-x86-64.so.2... (No debugging symbols found in /lib64/ld-linux-x86-64.so.2) 0x00007f502130bf27 in pause () from /lib64/libc.so.6 (gdb) p foo symtab.c:6417: internal-error: CORE_ADDR get_msymbol_address(objfile*, const minimal_symbol*): Assertion `(objf->flags & OBJF_MAINLINE) == 0' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. The add-symbol-file command causes the symbols to be loaded without the SYMFILE_MAINLINE (and hence the OBJFILE_MAINLINE) flags being set. This, in turn, causes the "maybe_copied" flag to be set for the global symbol (named "foo" in the provided test case). The attach command will cause another objfile to be created, but it will reuse the symtabs from the objfile created by add-symbol-file, leading to a situation in which the OBJFILE_MAINLINE flag will be set for the new (attach-created) objfile, however the "maybe_copied" flag will still be set for the global symbol. Had it been loaded anew, this flag would not be set due to OBJFILE_MAINLINE being set for the objfile. At present, minimal_symbol::value_address looks like this: CORE_ADDR minimal_symbol::value_address (objfile *objfile) const { if (this->maybe_copied (objfile)) return get_msymbol_address (objfile, this); else return (CORE_ADDR (this->unrelocated_address ()) + objfile->section_offsets[this->section_index ()]); } So, we can now see the problem: When the "maybe_copied" flag is set, get_msymbol_address() will be called. However, get_msymbol_address() assumes that it won't be called with the OBF_MAINLINE flag set for the objfile in question. It, in fact, contains an assert() which makes sure that this is the case: gdb_assert ((objf->flags & OBJF_MAINLINE) == 0); (If this assert is removed, then get_msymbol_address() recurses infinitely for the case under consideration.) So, the problem here is that the maybe_copied flag is set for the symbol AND the OBJF_MAINLINE flag is set for the objfile. As noted earlier, this happens due to add-symbol-file being used; this causes the maybe_copied flag to be set. Later, when the attach is performed, OBJF_MAINLINE will be set for that objfile, leading to this unfortunate situation. My first cut at a solution involved adjusting the MSYMBOL_VALUE_ADDRESS macro (which has since been changed to be the method noted above) to include a test of the OBJFILE_MAINLINE flag. However, Simon Marchi, in his review of my patch, suggested a better solution. Simon observed that the 'maybe_copied' flag is (was, after this commit) being set/initialized in record_minimal_symbol() using using the objfile in the context in which the symbol was created. Simon further observed: Today, a single copy is created, as symtabs are shared between objfiles. This means that everything that we store into a symbol must be independent of any objfile. However, the value of the maybe_copied field is dependent on the objfile in the context of which the symbol was created. Meaning that when the symbol is re-used in the context of another objfile, the maybe_copied value is not right in the context of that objfile. So I think it means there isn't a single "is this symbol maybe copied" value, but instead "is this symbol maybe copied, in the context of this given objfile". And the answer is yes or no, depending on whether the objfile is mainline. So maybe_copied should become a method that takes an objfile and returns an answer based on that. Simon's full review can be found here: https://sourceware.org/pipermail/gdb-patches/2021-May/178855.html Simon also provided a patch which implements this suggestion. The current patch is mostly his work, though I did make some adjustments during a rebase in addition to making some changes to account for a concern from Tom Tromey. During his review of the v3 series, Tom noted, "The old approach was specific to ELF, while the new approach will be used by any object format." Tom further observed, "...it seems like it could result in an incorrect evaluation in some scenario." This seemed plausible to me, so I introduced the flag 'object_format_has_copy_relocs' to struct objfile. It is set at the end of elf_symfile_read() in elfread.c. The minimal_symbol::maybe_copied method tests this new flag, forcing this method to return false when the flag is not set. If we find that other object file formats use the same copy reloc mechanism as ELF, then 'object_format_has_copy_relocs' should be set for objfiles using those formats. Lastly, I'll note that this is a strange use case. It's far more common to either let gdb figure out which file to load by itself when attaching, i.e. (gdb) attach 4104360 Attaching to process 4104360 Reading symbols from /tmp/add-symbol-file-attach... Reading symbols from /lib64/libc.so.6... (No debugging symbols found in /lib64/libc.so.6) Reading symbols from /lib64/ld-linux-x86-64.so.2... (No debugging symbols found in /lib64/ld-linux-x86-64.so.2) 0x00007fdb1fc33f27 in pause () from /lib64/libc.so.6 (gdb) p foo $1 = 42 ...or to use the "file" command prior to the attach, like this: (gdb) file add-symbol-file-attach Reading symbols from add-symbol-file-attach... (gdb) attach 4104360 Attaching to program: /tmp/add-symbol-file-attach, process 4104360 Reading symbols from /lib64/libc.so.6... (No debugging symbols found in /lib64/libc.so.6) Reading symbols from /lib64/ld-linux-x86-64.so.2... (No debugging symbols found in /lib64/ld-linux-x86-64.so.2) 0x00007fdb1fc33f27 in pause () from /lib64/libc.so.6 Both of these more common scenarios work perfectly fine; using "add-symbol-file" to load the program to which you will attach isn't recommended as a normal use case. That said, it's bad for gdb to assert, hence this fix. Reviewed-by: Simon Marchi <simon.marchi@polymtl.ca> Co-Authored-by: Simon Marchi <simon.marchi@polymtl.ca> Approved-by: Tom Tromey <tom@tromey.com> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27831
2023-06-05Use "unrelocated" terminology in linetable_entryTom Tromey1-2/+4
I forgot to convert struct linetable_entry to use the "unrelocated" (as opposed to "raw") terminology. This patch corrects the oversight.
2023-06-05Fix comment in address_classTom Tromey1-5/+5
enum address_class has a stale comment referring to MSYMBOL_VALUE_RAW_ADDRESS, which no longer exists. This patch updates the comment.
2023-06-05Move unrelocated_addr to common-types.hTom Tromey1-6/+0
unrelocated_addr is currently defined in symtab.h, but in order to avoid having to include that in more places, I wanted to move the type elsewhere. I considered defs.h, but it seemed reasonable to have it next to CORE_ADDR, which is what this patch does.
2023-05-12Introduce symbol_block_ops::get_block_valueTom Tromey1-0/+9
This adds a new callback to symbol_block_ops. This callback lets a LOC_BLOCK symbol implement its own function to find the underlying block.
2023-05-12Define symbol::value_block separatelyTom Tromey1-4/+7
This moves the definition of symbol::value_block outside of the class. A subsequent patch will change this method to use SYMBOL_BLOCK_OPS, and it seemed simplest to move this method out-of-line, and cleaner to do this as a separate change.
2023-03-28Rename "raw" to "unrelocated"Tom Tromey1-3/+3
Per an earlier discussion, this patch renames the existing "raw" APIs to use the word "unrelocated" instead.
2023-03-28Use unrelocated_addr in minimal symbolsTom Tromey1-2/+13
This changes minimal symbols to use unrelocated_addr. I believe this detected a latent bug in add_pe_forwarded_sym.
2023-03-28Use unrelocated_addr in psymbolsTom Tromey1-0/+16
This changes psymbols themselves to use unrelocated_addr. This transform is largely mechanical. I don't think it finds any bugs.
2023-03-28Move definition of unrelocated_addr earlierTom Tromey1-6/+6
This moves the definition of unrelocated_addr a bit earlier in symtab.h, so that it can be used elsewhere in the file.