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2021-02-04gdb: make record-full clear async handler in waitSimon Marchi2-1/+9
For the same reason explained in the previous patch (which was for the record-btrace target), move clearing of the async event handler of the record-full target to the wait method. I'm not sure if/where that target needs to re-set its async event handler in the wait method. Since it only supports a single thread, there probably can't be multiple events to report at the same time. gdb/ChangeLog: * record-full.c (record_full_async_inferior_event_handler): Don't clear async event handler. (record_full_base_target::wait): Clear async event handler at beginning. Change-Id: I146fbdb53d99e3a32766ac7cd337ac5ed7fd9adf
2021-02-04gdb: make record-btrace clear event handler in waitSimon Marchi2-1/+10
For the same reason explained in the previous patch (which was for the remote target), move clearing of the async event handler of the record-btrace target to the wait method. The record-btrace target already re-sets its async event handler in its wait method, so that part doesn't need to be changed: /* In async mode, we need to announce further events. */ if (target_is_async_p ()) record_btrace_maybe_mark_async_event (moving, no_history); gdb/ChangeLog: * record-btrace.c (record_btrace_handle_async_inferior_event): Don't clear async event handler. (record_btrace_target::wait): Clear async event handler at beginning. Change-Id: Ib32087a81bf94f1b884a938c8167ac8bbe09e362
2021-02-04gdb: make remote target clear its handler in remote_target::waitSimon Marchi2-20/+19
The remote target's remote_async_inferior_event_token is a flag that tells when it wants the infrun loop to call its wait method. The flag is cleared in the async_event_handler's callback (remote_async_inferior_event_handler), just before calling inferior_event_handler. However, since inferior_event_handler may actually call another target's wait method, there needs to be code that checks if we need to re-raise the flag. It would be simpler instead for remote_target::wait to clear the flag when it returns an event and there are no more to report after that. If another target's wait method gets called by inferior_event_handler, the remote target's flag will stay naturally stay marked. Note that this is already partially implemented in remote_target::wait, since the remote target may have multiple events to report (and it can only report one at the time): if (target_is_async_p ()) { remote_state *rs = get_remote_state (); /* If there are are events left in the queue tell the event loop to return here. */ if (!rs->stop_reply_queue.empty ()) mark_async_event_handler (rs->remote_async_inferior_event_token); } The code in remote_async_inferior_event_handler also checks for pending events as well, in addition to the stop reply queue, so I've made remote_target::wait check for that as well. I'm not completely sure this is ok, since I don't understand very well how the pending events mechanism works. But I figured it was safer to do this, worst case it just leads to unnecessary calls to remote_target::wait. gdb/ChangeLog: * remote.c (remote_target::wait): Clear async event handler at beginning, mark if needed at the end. (remote_async_inferior_event_handler): Don't set or clear async event handler. Change-Id: I20117f5b5acc8a9972c90f16280249b766c1bf37
2021-02-04gdb: make async event handlers clear themselvesSimon Marchi8-4/+33
The `ready` flag of async event handlers is cleared by the async event handler system right before invoking the associated callback, in check_async_event_handlers. This is not ideal with how the infrun subsystem consumes events: all targets' async event handler callbacks essentially just invoke `inferior_event_handler`, which eventually calls `fetch_inferior_event` and `do_target_wait`. `do_target_wait` picks an inferior at random, and thus a target at random (it could be the target whose `ready` flag was cleared, or not), and pulls one event from it. So it's possible that: - the async event handler for a target A is called - we end up consuming an event for target B - all threads of target B are stopped, target_async(0) is called on it, so its async event handler is cleared (e.g. record_btrace_target::async) As a result, target A still has events to report while its async event handler is left unmarked, so these events are not consumed. To counter this, at the end of their async event handler callbacks, targets check if they still have something to report and re-mark their async event handler (e.g. remote_async_inferior_event_handler). The linux_nat target does not suffer from this because it doesn't use an async event handler at the moment. It only uses a pipe registered with the event loop. It is written to in the SIGCHLD handler (and in other spots that want to get target wait method called) and read from in the target's wait method. So if linux_nat happened to be target A in the example above, the pipe would just stay readable, and the event loop would wake up again, until linux_nat's wait method is finally called and consumes the contents of the pipe. I think it would be nicer if targets using async_event_handler worked in a similar way, where the flag would stay set until the target's wait method is actually called. As a first step towards that, this patch moves the responsibility of clearing the ready flags of async event handlers to the invoked callback. All async event handler callbacks are modified to clear their ready flag before doing anything else. So in practice, nothing changes with this patch. It's only the responsibility of clearing the flag that is shifted toward the callee. gdb/ChangeLog: * async-event.h (async_event_handler_func): Add documentation. * async-event.c (check_async_event_handlers): Don't clear async_event_handler ready flag. * infrun.c (infrun_async_inferior_event_handler): Clear ready flag. * record-btrace.c (record_btrace_handle_async_inferior_event): Likewise. * record-full.c (record_full_async_inferior_event_handler): Likewise. * remote-notif.c (remote_async_get_pending_events_handler): Likewise. * remote.c (remote_async_inferior_event_handler): Likewise. Change-Id: I179ef8e99580eae642d332846fd13664dbddc0c1
2021-02-04libctf: always name nameless types "", never NULLNick Alcock4-8/+26
The ctf_type_name_raw and ctf_type_aname_raw functions, which return the raw, unadorned name of CTF types, have one unfortunate wrinkle: they return NULL not only on error but when returning the name of types without a name in writable dicts. This was unintended: it not only makes it impossible to reliably tell if a given call to ctf_type_name_raw failed (due to a bad string offset say), but also complicates all its callers, who now have to check for both NULL and "". The written-out form of CTF has no concept of a NULL pointer instead of a string: all null strings are strtab offset 0, "". So the more we can do to remove this distinction from the writable form, the less complex the rest of our code needs to be. Armour against NULL in multiple places, arranging to return "" from ctf_type_name_raw if offset 0 is passed in, and removing a risky optimization from ctf_str_add* that avoided doing anything if a NULL was passed in: this added needless irregularity to the functions' API surface, since "" and NULL should be treated identically, and in the case of ctf_str_add_ref, we shouldn't skip adding the passed-in REF to the list of references to be updated no matter what the content of the string happens to be. This means we can simplify the deduplicator a tiny bit, also fixing a bug (latent when used by ld) where if the input dict was writable, we failed to realise when types were nameless and could end up creating deeply unhelpful synthetic forwards with no name, which we just banned a few commits ago, so the link failed. libctf/ChangeLog 2021-01-27 Nick Alcock <nick.alcock@oracle.com> * ctf-string.c (ctf_str_add): Treat adding a NULL as adding "". (ctf_str_add_ref): Likewise. (ctf_str_add_external): Likewise. * ctf-types.c (ctf_type_name_raw): Always return "" for offset 0. * ctf-dedup.c (ctf_dedup_multiple_input_dicts): Don't armour against NULL name. (ctf_dedup_maybe_synthesize_forward): Likewise.
2021-02-04libctf: fix uninitialized variable in symbol serialization error handlingNick Alcock2-1/+4
We declare a variable to hold errors at two scopes, and then initialize the inner one and jump to a scope where only the outer one is in scope. The consequences are minor: only the version of the error message printed in the debugging stream is impacted. libctf/ChangeLog 2021-01-27 Nick Alcock <nick.alcock@oracle.com> * ctf-create.c (ctf_serialize): Fix shadowing.
2021-02-04libctf: prohibit nameless ints, floats, typedefs and forwardsNick Alcock4-4/+24
Now that "anonymous typedef nodes" have been extirpated, we can mandate that things that have names in C must have names in CTF too. (Unlike the no-forwards embarrassment, the deduplicator does nothing special with names: types that have names in C will have the same name in CTF. So we can assume that the CTF rules and the C rules are the same.) include/ChangeLog 2021-01-27 Nick Alcock <nick.alcock@oracle.com> * ctf-api.h (ECTF_NONAME): New. (ECTF_NERR): Adjust. libctf/ChangeLog 2021-01-27 Nick Alcock <nick.alcock@oracle.com> * ctf-create.c (ctf_add_encoded): Add check for non-empty name. (ctf_add_forward): Likewise. (ctf_add_typedef): Likewise.
2021-02-04libctf: rip out dead code handling typedefs with no nameNick Alcock4-61/+14
There is special code in libctf to handle typedefs with no name, which the code calls "anonymous typedef nodes". These monsters are obviously not something C programs can include: the whole point of a ttypedef is to introduce a new name. Looking back at the history of DWARF in GCC, the only thing (outside C++ anonymous namespaces) which can generate a DW_TAG_typedef without a DW_AT_name is obsolete code to handle the long-removed -feliminate-dwarf2-dups option. Looking at OpenSolaris, typedef nodes with no name couldn't be generated by the DWARF->CTF converter at all (and its deduplicator barfed on them): the only reason for the existence of this code is a special case working around a peculiarity of stabs whereby types could sometimes be referenced before they were introduced. We don't need to carry code in libctf to handle special cases in an obsolete OpenSolaris converter (that yields a format that isn't readable by libctf anyway). So drop it. libctf/ChangeLog 2021-01-27 Nick Alcock <nick.alcock@oracle.com> * ctf-open.c (init_types): Rip out code to check anonymous typedef nodes. * ctf-create.c (ctf_add_reftype): Likewise. * ctf-lookup.c (refresh_pptrtab): Likewise.
2021-02-04libctf, ld: fix symtypetab and var section population under ld -rNick Alcock17-57/+612
The variable section in a CTF dict is meant to contain the types of variables that do not appear in the symbol table (mostly file-scope static declarations). We implement this by having the compiler emit all potential data symbols into both sections, then delete those symbols from the variable section that correspond to data symbols the linker has reported. Unfortunately, the check for this in ctf_serialize is wrong: rather than checking the set of linker-reported symbols, we check the set of names in the data object symtypetab section: if the linker has reported no symbols at all (usually if ld -r has been run, or if a non-linker program that does not use symbol tables is calling ctf_link) this will include every single symbol, emptying the variable section completely. Worse, when ld -r is in use, we want to force writeout of every symtypetab entry on the inputs, in an indexed section, whether or not the linker has reported them, since this isn't a final link yet and the symbol table is not finalized (and may grow more symbols than the linker has yet reported). But the check for this is flawed too: we were relying on ctf_link_shuffle_syms not having been called if no symbols exist, but that function is *always* called by ld even when ld -r is in use: ctf_link_add_linker_symbol is the one that's not called when there are no symbols. We clearly need to rethink this. Using the emptiness of the set of reported symbols as a test for ld -r is just ugly: the linker already knows if ld -r is underway and can just tell us. So add a new linker flag CTF_LINK_NO_FILTER_REPORTED_SYMS that is set to stop the linker filtering the symbols in the symtypetab sections using the set that the linker has reported: use the presence or absence of this flag to determine whether to emit unindexed symtabs: we only remove entries from the variable section when filtering symbols, and we only remove them if they are in the reported symbol set, fixing the case where no symbols are reported by the linker at all. (The negative sense of the new CTF_LINK flag is intentional: the common case, both for ld and for simple tools that want to do a ctf_link with no ELF symbol table in sight, is probably to filter out symbols that no linker has reported: i.e., for the simple tools, all of them.) There's another wrinkle, though. It is quite possible for a non-linker to add symbols to a dict via ctf_add_*_sym and then write it out via the ctf_write APIs: perhaps it's preparing a dict for a later linker invocation. Right now this would not lead to anything terribly meaningful happening: ctf_serialize just assumes it was called via ctf_link if symbols are present. So add an (internal-to-libctf) flag that indicates that a writeout is happening via ctf_link_write, and set it there (propagating it to child dicts as needed). ctf_serialize can then spot when it is not being called by a linker, and arrange to always write out an indexed, sorted symtypetab for fastest possible future symbol lookup by name in that case. (The writeouts done by ld -r are unsorted, because the only thing likely to use those symtabs is the linker, which doesn't benefit from symtypetab sorting.) Tests added for all three linking cases (ld -r, ld -shared, ld), with a bit of testsuite framework enhancement to stop it unconditionally linking the CTF to be checked by the lookup program with -shared, so tests can now examine CTF linked with -r or indeed with no flags at all, though the output filename is still foo.so even in this case. Another test added for the non-linker case that endeavours to determine whether the symtypetab is sorted by examining the order of entries returned from ctf_symbol_next: nobody outside libctf should rely on this ordering, but this test is not outside libctf :) include/ChangeLog 2021-01-26 Nick Alcock <nick.alcock@oracle.com> * ctf-api.h (CTF_LINK_NO_FILTER_REPORTED_SYMS): New. ld/ChangeLog 2021-01-26 Nick Alcock <nick.alcock@oracle.com> * ldlang.c (lang_merge_ctf): Set CTF_LINK_NO_FILTER_REPORTED_SYMS when appropriate. libctf/ChangeLog 2021-01-27 Nick Alcock <nick.alcock@oracle.com> * ctf-impl.c (_libctf_nonnull_): Add parameters. (LCTF_LINKING): New flag. (ctf_dict_t) <ctf_link_flags>: Mention it. * ctf-link.c (ctf_link): Keep LCTF_LINKING set across call. (ctf_write): Likewise, including in child dictionaries. (ctf_link_shuffle_syms): Make sure ctf_dynsyms is NULL if there are no reported symbols. * ctf-create.c (symtypetab_delete_nonstatic_vars): Make sure the variable has been reported as a symbol by the linker. (symtypetab_skippable): Mention relationship between SYMFP and the flags. (symtypetab_density): Adjust nonnullity. Exit early if no symbols were reported and force-indexing is off (i.e., we are doing a final link). (ctf_serialize): Handle the !LCTF_LINKING case by writing out an indexed, sorted symtypetab (and allow SYMFP to be NULL in this case). Turn sorting off if this is a non-final link. Only delete nonstatic vars if we are filtering symbols and the linker has reported some. * testsuite/libctf-regression/nonstatic-var-section-ld-r*: New test of variable and symtypetab section population when ld -r is used. * testsuite/libctf-regression/nonstatic-var-section-ld-executable.lk: Likewise, when ld of an executable is used. * testsuite/libctf-regression/nonstatic-var-section-ld.lk: Likewise, when ld -shared alone is used. * testsuite/libctf-regression/nonstatic-var-section-ld*.c: Lookup programs for the above. * testsuite/libctf-writable/symtypetab-nonlinker-writeout.*: New test, testing survival of symbols across ctf_write paths. * testsuite/lib/ctf-lib.exp (run_lookup_test): New option, nonshared, suppressing linking of the SOURCE with -shared.
2021-02-04x86-64: Provide more info when failed to convert GOTPCRELH.J. Lu10-10/+34
Provide [hjl@gnu-cfl-2 ld]$ ./ld-new -z norelro -L/export/gnu/import/git/gitlab/x86-binutils/ld/testsuite/ld-x86-64 -melf32_x86_64 -Ttext=0x80000000 -o tmpdir/dump tmpdir/pr19609-7.o tmpdir/pr19609-7.o: in function `_start': (.text+0x2): failed to convert GOTPCREL relocation against 'foobar'; relink with --no-relax [hjl@gnu-cfl-2 ld]$ instead of [hjl@gnu-cfl-2 ld]$ ld -z norelro -L/export/gnu/import/git/gitlab/x86-binutils/ld/testsuite/ld-x86-64 -melf32_x86_64 -Ttext=0x80000000 -o tmpdir/dump tmpdir/pr19609-7.o ld: failed to convert GOTPCREL relocation; relink with --no-relax [hjl@gnu-cfl-2 ld]$ bfd/ PR ld/19609 * elf64-x86-64.c (elf_x86_64_relocate_section): Provide more info when failed to convert GOTPCREL relocation. ld/ PR ld/19609 * testsuite/ld-x86-64/pr19609-2a.d: Updated. * testsuite/ld-x86-64/pr19609-2b.d: Likewise. * testsuite/ld-x86-64/pr19609-4a.d: Likewise. * testsuite/ld-x86-64/pr19609-4c.d: Likewise. * testsuite/ld-x86-64/pr19609-5d.d: Likewise. * testsuite/ld-x86-64/pr19609-7a.d: Likewise. * testsuite/ld-x86-64/pr19609-7c.d: Likewise.
2021-02-04ld: Restore PR ld/15146 testsH.J. Lu7-0/+57
commit 7d409ac001cce916661d345bff01ed589991e762 Author: Alan Modra <amodra@gmail.com> Date: Thu Feb 4 13:56:34 2021 +1030 PR27311, (symbol from plugin): undefined reference, hidden sym fixed PR ld/15146. Restore PR ld/15146 tests. PR ld/15146 * testsuite/ld-plugin/lto.exp: Run PR ld/15146 tests. * testsuite/ld-plugin/pr15146.d: Restored. * testsuite/ld-plugin/pr15146a.c: Likewise. * testsuite/ld-plugin/pr15146b.c: Likewise. * testsuite/ld-plugin/pr15146c.c: Likewise. * testsuite/ld-plugin/pr15146d.c: Likewise.
2021-02-04RISC-V: Removed the v0.93 bitmanip ZBA/ZBB/ZBC instructions.Nelson Chu12-326/+28
bfd/ * elfxx-riscv.c (riscv_parse_prefixed_ext): Removed zb*. gas/ * config/tc-riscv.c (riscv_multi_subset_supports): Removed INSN_CLASS_ZB*. * testsuite/gas/riscv/bitmanip-insns-32.d: Removed. * testsuite/gas/riscv/bitmanip-insns-64.d: Removed. * testsuite/gas/riscv/bitmanip-insns.s: Removed. include/ * opcode/riscv-opc.h: Removed macros for zb* extensions. * opcode/riscv.h (riscv_insn_class): Removed INSN_CLASS_ZB*. opcodes/ * riscv-opc.c (MASK_RVB_IMM): Removed. (riscv_opcodes): Removed zb* instructions. (riscv_ext_version_table): Removed versions for zb*.
2021-02-04PR27311, (symbol from plugin): undefined reference, hidden symAlan Modra5-2/+27
bfd/ PR 27311 * elflink.c (elf_link_add_object_symbols): Don't pull in as-needed libraries for IR references on pass over libraries after LTO recompilation. ld/ * testsuite/ld-plugin/pr27311d.c: New test. * testsuite/ld-plugin/lto.exp: Rename pr27311 to pr27311-1, compile and link new test as pr27311-2.
2021-02-04Automatic date update in version.inGDB Administrator1-1/+1
2021-02-03gdb: infrun: move stop_soon variable to inner scoped in handle_inferior_eventSimon Marchi2-66/+71
Moving it to an inner scope makes it clearer where it's used (only while handling the TARGET_WAITKIND_LOADED event). gdb/ChangeLog: * infrun.c (handle_inferior_event): Move stop_soon variable to inner scope. Change-Id: Ic57685a21714cfbb38f1487ee96cea1d12b44652
2021-02-03IBM Z: Add missing vector formats to .insn docsAndreas Krebbel2-1/+53
gas/ * doc/c-s390.texi: Document vector instruction formats.
2021-02-03Re: PR27311, ld.bfd (symbol from plugin): undefined referenceAlan Modra2-15/+17
This does exactly the same as making decisions based on an override in _bfd_elf_add_default_symbol, and is simpler. PR 27311 * elflink.c (_bfd_elf_add_default_symbol): Revert last two changes. (elf_link_add_object_symbols): Here too. Don't pull in as-needed libraries when H is an indirect symbol after calling _bfd_elf_add_default_symbol.
2021-02-03pr27270 and pr27284, ar segfaults and wrong file modeAlan Modra4-28/+50
PR 27270 PR 27284 PR 26945 * ar.c: Don't include libbfd.h. (write_archive): Replace xmalloc+strcpy with xstrdup. Use bfd_stat rather than fstat on iostream. Move stat and fd tests outside of _WIN32 ifdef. Delete skip_stat variable. * arsup.c (temp_name, real_ofd): New static variables. (ar_open): Use make_tempname and bfd_fdopenw. (ar_save): Adjust to suit ar_open changes. Move stat output of _WIN32 ifdef. * objcopy.c: Don't include libbfd.h. (copy_file): Use bfd_stat.
2021-02-03PR27311 again, ld.bfd (symbol from plugin): undefined referenceAlan Modra4-3/+18
bfd/ PR 27311 * elflink.c (_bfd_elf_add_default_symbol): Clear override when undecorated symbol will have a different version. ld/ * testsuite/ld-ifunc/ifunc.exp (libpr16467b.so, libpr16467bn.so): Link with --as-needed.
2021-02-03Testcase for detaching while stepping over breakpointPedro Alves3-0/+407
This adds a testcase that exercises detaching while GDB is stepping over a breakpoint, in all combinations of: - maint target non-stop off/on - set non-stop on/off - displaced stepping on/off This exercises the bugs fixed in the previous 8 patches. gdb/testsuite/ChangeLog: * gdb.threads/detach-step-over.c: New file. * gdb.threads/detach-step-over.exp: New file.
2021-02-03detach in all-stop with threads runningPedro Alves4-52/+138
A following patch will add a testcase that has a number of threads constantly stepping over a breakpoint, and then has GDB detach the process, while threads are running. If we have more than one inferior running, and we detach from just one of the inferiors, we expect that the remaining inferior continues running. However, in all-stop, if GDB needs to pause the target for the detach, nothing is re-resuming the other inferiors after the detach. "info threads" shows the threads as running, but they really aren't. This fixes it. gdb/ChangeLog: * infcmd.c (detach_command): Hold strong reference to target, and if all-stop on entry, restart threads on exit. * infrun.c (switch_back_to_stepped_thread): Factor out bits to ... (restart_stepped_thread): ... this new function. Also handle trap_expected. (restart_after_all_stop_detach): New function. * infrun.h (restart_after_all_stop_detach): Declare.
2021-02-03detach with in-line step over in progressPedro Alves2-4/+46
A following patch will add a testcase that has a number of threads constantly stepping over a breakpoint, and then has GDB detach the process. That testcase exercises both "set displaced-stepping on/off". Testing with "set displaced-stepping off" reveals that GDB does not handle the case of the user typing "detach" just while some thread is in the middle of an in-line step over. If that thread belongs to the inferior that is being detached, then the step-over never finishes, and threads of other inferiors are never re-resumed. This fixes it. gdb/ChangeLog: * infrun.c (struct step_over_info): Initialize fields. (prepare_for_detach): Handle ongoing in-line step over.
2021-02-03detach and breakpoint removalPedro Alves5-9/+30
A following patch will add a testcase that has a number of threads constantly stepping over a breakpoint, and then has GDB detach the process. That testcase sometimes fails with the inferior crashing with SIGTRAP after the detach because of the bug fixed by this patch, when tested with the native target. The problem is that target_detach removes breakpoints from the target immediately, and that does not work with the native GNU/Linux target (and probably no other native target) currently. The test wouldn't fail with this issue when testing against gdbserver, because gdbserver does allow accessing memory while the current thread is running, by transparently pausing all threads temporarily, without GDB noticing. Implementing that in gdbserver was a lot of work, so I'm not looking forward right now to do the same in the native target. Instead, I came up with a simpler solution -- push the breakpoints removal down to the targets. The Linux target conveniently already pauses all threads before detaching them, since PTRACE_DETACH only works with stopped threads, so we move removing breakpoints to after that. Only the remote and GNU/Linux targets support support async execution, so no other target should really need this. gdb/ChangeLog: * linux-nat.c (linux_nat_target::detach): Remove breakpoints here... * remote.c (remote_target::remote_detach_1): ... and here ... * target.c (target_detach): ... instead of here. * target.h (target_ops::detach): Add comment.
2021-02-03prepare_for_detach and ongoing displaced steppingPedro Alves2-57/+77
I noticed that "detach" while a program was running sometimes resulted in the process crashing. I tracked it down to this change to prepare_for_detach in commit 187b041e ("gdb: move displaced stepping logic to gdbarch, allow starting concurrent displaced steps"): /* Is any thread of this process displaced stepping? If not, there's nothing else to do. */ - if (displaced->step_thread == nullptr) + if (displaced_step_in_progress (inf)) return; The problem above is that the condition was inadvertently flipped. It should have been: if (!displaced_step_in_progress (inf)) So I fixed it, and wrote a testcase to exercise it. The testcase has a number of threads constantly stepping over a breakpoint, and then GDB detaches the process, while threads are running and stepping over the breakpoint. And then I was surprised that my testcase would hang -- GDB would get stuck in an infinite loop in prepare_for_detach, here: while (displaced_step_in_progress (inf)) { ... What is going on is that since we now have two displaced stepping buffers, as one displaced step finishes, GDB starts another, and there's another one already in progress, and on and on, so the displaced_step_in_progress condition never turns false. This happens because we go via the whole handle_inferior_event, which tries to start new step overs when one finishes. And also because while we remove breakpoints from the target before prepare_for_detach is called, handle_inferior_event ends up calling insert_breakpoints via e.g. keep_going. Thinking through all this, I came to the conclusion that going through the whole handle_inferior_event isn't ideal. A _lot_ is done by that function, e.g., some thread may get a signal which is passed to the inferior, and gdb decides to try to get over the signal handler, which reinstalls breakpoints. Or some process may exit. We can end up reporting these events via normal_stop while detaching, maybe end up running some breakpoint commands, or maybe even something runs an inferior function call. Etc. All this after the user has already declared they don't want to debug the process anymore, by asking to detach. I came to the conclusion that it's better to do the minimal amount of work possible, in a more controlled fashion, without going through handle_inferior_event. So in the new approach implemented by this patch, if there are threads of the inferior that we're detaching in the middle of a displaced step, stop them, and cancel the displaced step. This is basically what stop_all_threads already does, via wait_one and (the now factored out) handle_one, so I'm reusing those. gdb/ChangeLog: * infrun.c (struct wait_one_event): Move higher up. (prepare_for_detach): Abort in-progress displaced steps instead of letting them complete. (handle_one): If the inferior is detaching, don't add the thread back to the global step-over chain. (restart_threads): Don't restart threads if detaching. (handle_signal_stop): Remove inferior::detaching reference.
2021-02-03prepare_for_detach: don't release scoped_restore at the endPedro Alves2-6/+6
After detaching from a process, the inf->detaching flag is inadvertently left set to true. If you afterwards reuse the same inferior to start a new process, GDB will mishave... The problem is that prepare_for_detach discards the scoped_restore at the end, while the intention is for the flag to be set only for the duration of prepare_for_detach. This was already a bug in the original commit that added prepare_for_detach, commit 24291992dac3 ("PR gdb/11321"), by yours truly. Back then, we still used cleanups, and the function called discard_cleanups instead of do_cleanups, by mistake. gdb/ChangeLog: * infrun.c (prepare_for_detach): Don't release scoped_restore before returning.
2021-02-03Factor out after-stop event handling code from stop_all_threadsPedro Alves2-138/+157
This moves the code handling an event out of wait_one to a separate function, to be used in another context in a following patch. gdb/ChangeLog: * infrun.c (handle_one): New function, factored out from ... (stop_all_threads): ... here.
2021-02-03gdbserver: spurious SIGTRAP w/ detach while step-over in progressPedro Alves2-1/+33
A following patch will add a new testcase that has two processes, each with a number of threads constantly tripping a breakpoint and stepping over it, because the breakpoint has a condition that evals false. Then GDB detaches from one of the processes, while both processes are running. And then the testcase sends a SIGUSR1 to the other process. When run against gdbserver, that would occasionaly fail like this: (gdb) PASS: gdb.threads/detach-step-over.exp: iter 1: detach Executing on target: kill -SIGUSR1 208303 (timeout = 300) spawn -ignore SIGHUP kill -SIGUSR1 208303 Thread 2.5 "detach-step-ove" received signal SIGTRAP, Trace/breakpoint trap. [Switching to Thread 208303.208305] 0x000055555555522a in thread_func (arg=0x0) at /home/pedro/gdb/binutils-gdb/src/gdb/testsuite/gdb.threads/detach-step-over.c:54 54 counter++; /* Set breakpoint here. */ What happened was that GDBserver is doing a step-over for process A when a detach request for process B arrives. And that generates a spurious SIGTRAP report for process A, as seen above. The GDBserver logs reveal what happened: - GDB manages to detach while a step over is in progress. That reaches linux_process_target::complete_ongoing_step_over(), which does: /* Passing NULL_PTID as filter indicates we want all events to be left pending. Eventually this returns when there are no unwaited-for children left. */ ret = wait_for_event_filtered (minus_one_ptid, null_ptid, &wstat, __WALL); As the comment say, this leaves all events pending, _including_ the just finished step SIGTRAP. We never discard that SIGTRAP. So GDBserver reports the SIGTRAP to GDB. GDB can't explain the SIGTRAP, so it reports it to the user. The GDBserver log looks like this. The LWP of interest is 208305: Need step over [LWP 208305]? yes, found breakpoint at 0x555555555227 proceed_all_lwps: found thread 208305 needing a step-over Starting step-over on LWP 208305. Stopping all threads 208305 starts a step-over. >>>> entering void linux_process_target::stop_all_lwps(int, lwp_info*) stop_all_lwps (stop-and-suspend, except=LWP 208303.208305) Sending sigstop to lwp 208303 Sending sigstop to lwp 207755 wait_for_sigstop: pulling events LWFE: waitpid(-1, ...) returned 207755, ERRNO-OK LLW: waitpid 207755 received Stopped (signal) (stopped) pc is 0x7f7e045593bf Expected stop. LLW: SIGSTOP caught for LWP 207755.207755 while stopping threads. LWFE: waitpid(-1, ...) returned 208303, ERRNO-OK LLW: waitpid 208303 received Stopped (signal) (stopped) pc is 0x7ffff7e743bf Expected stop. LLW: SIGSTOP caught for LWP 208303.208303 while stopping threads. LWFE: waitpid(-1, ...) returned 0, ERRNO-OK leader_pid=208303, leader_lp!=NULL=1, num_lwps=11, zombie=0 leader_pid=207755, leader_lp!=NULL=1, num_lwps=11, zombie=0 LLW: exit (no unwaited-for LWP) stop_all_lwps done, setting stopping_threads back to !stopping <<<< exiting void linux_process_target::stop_all_lwps(int, lwp_info*) Done stopping all threads for step-over. pc is 0x555555555227 Writing 8b to 0x555555555227 in process 208305 Could not findsigchld_handler fast tracepoint jump at 0x555555555227 in list (uninserting). pending reinsert at 0x555555555227 step from pc 0x555555555227 Resuming lwp 208305 (step, signal 0, stop expected) <<<< exiting ptid_t linux_process_target::wait_1(ptid_t, target_waitstatus*, target_wait_flags) handling possible serial event getpkt ("D;32b8b"); [no ack sent] The detach request arrives. sigchld_handler Tracing is already off, ignoring detach: step over in progress, finish it first GDBserver realizes a step over for 208305 was in progress, let's it finish. LWFE: waitpid(-1, ...) returned 208305, ERRNO-OK LLW: waitpid 208305 received Stopped (signal) (stopped) pc is 0x555555555227 Expected stop. LLW: step LWP 208303.208305, 0, 0 (discard delayed SIGSTOP) pending reinsert at 0x555555555227 step from pc 0x555555555227 Resuming lwp 208305 (step, signal 0, stop not expected) LWFE: waitpid(-1, ...) returned 0, ERRNO-OK leader_pid=208303, leader_lp!=NULL=1, num_lwps=11, zombie=0 leader_pid=207755, leader_lp!=NULL=1, num_lwps=11, zombie=0 sigsuspend'ing LWFE: waitpid(-1, ...) returned 208305, ERRNO-OK LLW: waitpid 208305 received Trace/breakpoint trap (stopped) pc is 0x55555555522a CSBB: LWP 208303.208305 stopped by trace LWFE: waitpid(-1, ...) returned 0, ERRNO-OK leader_pid=208303, leader_lp!=NULL=1, num_lwps=11, zombie=0 leader_pid=207755, leader_lp!=NULL=1, num_lwps=11, zombie=0 LLW: exit (no unwaited-for LWP) Finished step over. The step-over for 208305 finishes. Writing cc to 0x555555555227 in process 208305 Could not find fast tracepoint jump at 0x555555555227 in list (reinserting). >>>> entering void linux_process_target::stop_all_lwps(int, lwp_info*) stop_all_lwps (stop, except=none) wait_for_sigstop: pulling events The detach proceeds (snipped). ... proceed_one_lwp: lwp 208305 LWP 208305 has pending status, leaving stopped Later on, 208305 has a pending status (the step SIGTRAP from the step-over), so GDBserver starts the process of reporting it. ... wait_1 ret = LWP 208303.208305, 1, 5 <<<< exiting ptid_t linux_process_target::wait_1(ptid_t, target_waitstatus*, target_wait_flags) ... and eventually GDB receives the stop notification (T05 == SIGTRAP): getpkt ("vStopped"); [no ack sent] sigchld_handler vStopped: acking 3 Writing resume reply for LWP 208303.208305:1 putpkt ("$T0506:f0ee58f7ff7f0* ;07:f0ee58f7ff7f0* ;10:2a525*"550* ;thread:p32daf.32db1;core:c;#37"); [noack mode] From the GDB side, we see: [infrun] fetch_inferior_event: enter [infrun] fetch_inferior_event: fetch_inferior_event enter [infrun] do_target_wait: Found 2 inferiors, starting at #1 [infrun] print_target_wait_results: target_wait (-1.0.0 [process -1], status) = [infrun] print_target_wait_results: 208303.208305.0 [Thread 208303.208305], [infrun] print_target_wait_results: status->kind = stopped, signal = GDB_SIGNAL_TRAP [infrun] handle_inferior_event: status->kind = stopped, signal = GDB_SIGNAL_TRAP [infrun] start_step_over: enter [infrun] start_step_over: stealing global queue of threads to step, length = 6 [infrun] operator(): putting back 6 threads to step in global queue [infrun] start_step_over: exit [infrun] handle_signal_stop: context switch [infrun] context_switch: Switching context from process 0 to Thread 208303.208305 [infrun] handle_signal_stop: stop_pc=0x55555555522a [infrun] handle_signal_stop: random signal (GDB_SIGNAL_TRAP) [infrun] stop_waiting: stop_waiting [infrun] stop_all_threads: starting The fix is to discard the step SIGTRAP, unless GDB wanted the thread to step. gdbserver/ChangeLog: * linux-low.cc (linux_process_target::complete_ongoing_step_over): Discard step SIGTRAP, unless GDB wanted the thread to step.
2021-02-03Fix a couple vStopped pending ack bugsPedro Alves4-9/+34
A following patch will add a testcase that has two processes with threads stepping over a breakpoint continuously, and then detaches from one of the processes while threads are running. The other process continues stepping over its breakpoint. And then the testcase sends a SIGUSR1, expecting that GDB reports it. That would sometimes hang against gdbserver, due to the bugs fixed here. Both bugs are related, in that they're about remote protocol asynchronous Stop notifications. There's a bug in GDB, and another in GDBserver. The GDB bug: - when we detach from a process, the remote target discards any pending RSP notification related to that process, including the in-flight, yet-unacked notification. Discarding the in-flight notification is the problem. Until the in-flight notification is acked with a vStopped packet, the server won't send another %Stop notification. As a result, the debug session gets messed up. In the new testcase's case, GDB would hang inside stop_all_threads, waiting for a stop for one of the process'es threads, which never arrived -- its stop reply was permanently stuck in the stop reply queue, waiting for a vStopped packet that never arrived. In summary: 1. GDBserver sends stop notification about thread X, the remote target receives it and stores it 2. At the same time, GDB detaches thread X's inferior 3. The remote target discards the received stop notification 4. GDBserver waits forever for the ack The GDBserver bug: GDBserver has the opposite bug. It also discards notifications for the process being detached. If that discards the head of the notification queue, when gdb sends an ack, it ends up acking the _next_ notification. Meaning, gdb loses one notification. In the testcase, this results in a similar hang in stop_all_threads. So we have two very similar bugs in GDB and GDBserver, both resulting in a similar symptom. That's why I'm fixing them both at the same time. gdb/ChangeLog: * remote.c (remote_notif_stop_ack): Don't error out on TARGET_WAITKIND_IGNORE; instead, just ignore the notification. (remote_target::discard_pending_stop_replies): Don't delete in-flight notification; instead, clear its contents. gdbserver/ChangeLog: * server.cc (discard_queued_stop_replies): Don't ever discard the notification at the head of the list.
2021-02-03Testcase for attaching in non-stop modePedro Alves3-0/+211
This adds a testcase exercising attaching to a multi-threaded process, in all combinations of: - set non-stop on/off - maint target non-stop off/on - "attach" vs "attach &" This exercises the bugs fixed in the two previous patches. gdb/testsuite/ChangeLog: * gdb.threads/attach-non-stop.c: New file. * gdb.threads/attach-non-stop.exp: New file.
2021-02-03Fix "target extended-remote" + "maint set target-non-stop" + "attach"Pedro Alves2-1/+11
With "target extended-remote" + "maint set target-non-stop", attaching hangs like so: (gdb) attach 1244450 Attaching to process 1244450 [New Thread 1244450.1244450] [New Thread 1244450.1244453] [New Thread 1244450.1244454] [New Thread 1244450.1244455] [New Thread 1244450.1244456] [New Thread 1244450.1244457] [New Thread 1244450.1244458] [New Thread 1244450.1244459] [New Thread 1244450.1244461] [New Thread 1244450.1244462] [New Thread 1244450.1244463] * hang * Attaching to the hung GDB shows that GDB is busy in an infinite loop in stop_all_threads: (top-gdb) bt #0 stop_all_threads () at /home/pedro/gdb/binutils-gdb/src/gdb/infrun.c:4755 #1 0x000055555597b424 in stop_waiting (ecs=0x7fffffffd930) at /home/pedro/gdb/binutils-gdb/src/gdb/infrun.c:7738 #2 0x0000555555976fba in handle_signal_stop (ecs=0x7fffffffd930) at /home/pedro/gdb/binutils-gdb/src/gdb/infrun.c:5868 #3 0x0000555555975f6a in handle_inferior_event (ecs=0x7fffffffd930) at /home/pedro/gdb/binutils-gdb/src/gdb/infrun.c:5527 #4 0x0000555555971da4 in fetch_inferior_event () at /home/pedro/gdb/binutils-gdb/src/gdb/infrun.c:3910 #5 0x00005555559540b2 in inferior_event_handler (event_type=INF_REG_EVENT) at /home/pedro/gdb/binutils-gdb/src/gdb/inf-loop.c:42 #6 0x000055555597e825 in infrun_async_inferior_event_handler (data=0x0) at /home/pedro/gdb/binutils-gdb/src/gdb/infrun.c:9162 #7 0x0000555555687d1d in check_async_event_handlers () at /home/pedro/gdb/binutils-gdb/src/gdb/async-event.c:328 #8 0x0000555555e48284 in gdb_do_one_event () at /home/pedro/gdb/binutils-gdb/src/gdbsupport/event-loop.cc:216 #9 0x00005555559e7512 in start_event_loop () at /home/pedro/gdb/binutils-gdb/src/gdb/main.c:347 #10 0x00005555559e765d in captured_command_loop () at /home/pedro/gdb/binutils-gdb/src/gdb/main.c:407 #11 0x00005555559e8f80 in captured_main (data=0x7fffffffdb70) at /home/pedro/gdb/binutils-gdb/src/gdb/main.c:1239 #12 0x00005555559e8ff2 in gdb_main (args=0x7fffffffdb70) at /home/pedro/gdb/binutils-gdb/src/gdb/main.c:1254 #13 0x0000555555627c86 in main (argc=12, argv=0x7fffffffdc88) at /home/pedro/gdb/binutils-gdb/src/gdb/gdb.c:32 The problem is that the remote sends stops for all the threads: Packet received: l/home/pedro/gdb/binutils-gdb/build/gdb/testsuite/outputs/gdb.threads/attach-non-stop/attach-non-stop Sending packet: $vStopped#55...Packet received: T0006:f06e25edec7f0000;07:f06e25edec7f0000;10:f14190ccf4550000;thread:p12fd22.12fd2f;core:15; Sending packet: $vStopped#55...Packet received: T0006:f0dea5f0ec7f0000;07:f0dea5f0ec7f0000;10:e84190ccf4550000;thread:p12fd22.12fd27;core:4; Sending packet: $vStopped#55...Packet received: T0006:f0ee25f1ec7f0000;07:f0ee25f1ec7f0000;10:f14190ccf4550000;thread:p12fd22.12fd26;core:5; Sending packet: $vStopped#55...Packet received: T0006:f0bea5efec7f0000;07:f0bea5efec7f0000;10:f14190ccf4550000;thread:p12fd22.12fd29;core:1; Sending packet: $vStopped#55...Packet received: T0006:f0ce25f0ec7f0000;07:f0ce25f0ec7f0000;10:e84190ccf4550000;thread:p12fd22.12fd28;core:a; Sending packet: $vStopped#55...Packet received: T0006:f07ea5edec7f0000;07:f07ea5edec7f0000;10:e84190ccf4550000;thread:p12fd22.12fd2e;core:f; Sending packet: $vStopped#55...Packet received: T0006:f0ae25efec7f0000;07:f0ae25efec7f0000;10:df4190ccf4550000;thread:p12fd22.12fd2a;core:6; Sending packet: $vStopped#55...Packet received: T0006:0000000000000000;07:c0e8a381fe7f0000;10:bf43b4f1ec7f0000;thread:p12fd22.12fd22;core:2; Sending packet: $vStopped#55...Packet received: T0006:f0fea5f1ec7f0000;07:f0fea5f1ec7f0000;10:df4190ccf4550000;thread:p12fd22.12fd25;core:8; Sending packet: $vStopped#55...Packet received: T0006:f09ea5eeec7f0000;07:f09ea5eeec7f0000;10:e84190ccf4550000;thread:p12fd22.12fd2b;core:b; Sending packet: $vStopped#55...Packet received: OK But then wait_one never consumes them, always hitting this path: 4473 if (nfds == 0) 4474 { 4475 /* No waitable targets left. All must be stopped. */ 4476 return {NULL, minus_one_ptid, {TARGET_WAITKIND_NO_RESUMED}}; 4477 } Resulting in GDB constanly calling target_stop to stop threads, but the remote target never reporting back the stops to infrun. That TARGET_WAITKIND_NO_RESUMED path shown above is always taken because here, in wait_one too, just above: 4428 for (inferior *inf : all_inferiors ()) 4429 { 4430 process_stratum_target *target = inf->process_target (); 4431 if (target == NULL 4432 || !target->is_async_p () ^^^^^^^^^^^^^^^^^^^^^ 4433 || !target->threads_executing) 4434 continue; ... the remote target is not async. And in turn that happened because extended_remote_target::attach misses enabling async in the target-non-stop path. A testcase exercising this will be added in a following patch. gdb/ChangeLog: * remote.c (extended_remote_target::attach): Set target async in the target-non-stop path too.
2021-02-03Fix attaching in non-stop mode (PR gdb/27055)Pedro Alves2-15/+11
Attaching in non-stop mode currently misbehaves, like so: (gdb) attach 1244450 Attaching to process 1244450 [New LWP 1244453] [New LWP 1244454] [New LWP 1244455] [New LWP 1244456] [New LWP 1244457] [New LWP 1244458] [New LWP 1244459] [New LWP 1244461] [New LWP 1244462] [New LWP 1244463] No unwaited-for children left. At this point, GDB's stopped/running thread state is out of sync with the inferior: (gdb) info threads Id Target Id Frame * 1 LWP 1244450 "attach-non-stop" 0xf1b443bf in ?? () 2 LWP 1244453 "attach-non-stop" (running) 3 LWP 1244454 "attach-non-stop" (running) 4 LWP 1244455 "attach-non-stop" (running) 5 LWP 1244456 "attach-non-stop" (running) 6 LWP 1244457 "attach-non-stop" (running) 7 LWP 1244458 "attach-non-stop" (running) 8 LWP 1244459 "attach-non-stop" (running) 9 LWP 1244461 "attach-non-stop" (running) 10 LWP 1244462 "attach-non-stop" (running) 11 LWP 1244463 "attach-non-stop" (running) (gdb) (gdb) interrupt -a (gdb) *nothing* The problem is that attaching installs an inferior continuation, called when the target reports the initial attach stop, here, in inf-loop.c:inferior_event_handler: /* Do all continuations associated with the whole inferior (not a particular thread). */ if (inferior_ptid != null_ptid) do_all_inferior_continuations (0); However, currently in non-stop mode, inferior_ptid is still null_ptid when we get here. If you try to do "set debug infrun 1" to debug the problem, however, then the attach completes correctly, with GDB reporting a stop for each thread. The bug is that we're missing a switch_to_thread/context_switch call when handling the initial stop, here: if (stop_soon == STOP_QUIETLY_NO_SIGSTOP && (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_STOP || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_0)) { stop_print_frame = true; stop_waiting (ecs); ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0; return; } Note how the STOP_QUIETLY / STOP_QUIETLY_REMOTE case above that does call context_switch. And the reason "set debug infrun 1" "fixes" it, is that the debug path has a switch_to_thread call. This patch fixes it by moving the main context_switch call earlier. It also removes the: if (ecs->ptid != inferior_ptid) check at the same time because: #1 - that is half of what context_switch already does #2 - deprecated_context_hook is only used in Insight, and all it does is set an int. It won't care if we call it when the current thread hasn't actually changed. A testcase exercising this will be added in a following patch. gdb/ChangeLog: PR gdb/27055 * infrun.c (handle_signal_stop): Move main context_switch call earlier, before STOP_QUIETLY_NO_SIGSTOP.
2021-02-03Automatic date update in version.inGDB Administrator1-1/+1
2021-02-02Inferior without argument prints detail of current inferior.Lancelot SIX8-21/+135
This patch makes the inferior command display information about the current inferior when called with no argument. This behavior is similar to the one of the thread command. Before patch: (gdb) info inferior Num Description Connection Executable * 1 process 19221 1 (native) /home/lsix/tmp/a.out 2 process 19239 1 (native) /home/lsix/tmp/a.out (gdb) inferior 2 [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)] [Switching to thread 2.1 (process 19239)] #0 0x0000000000401146 in main () (gdb) inferior Argument required (expression to compute). After patch: (gdb) info inferior Num Description Connection Executable * 1 process 18699 1 (native) /home/lsix/tmp/a.out 2 process 18705 1 (native) /home/lsix/tmp/a.out (gdb) inferior 2 [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)] [Switching to thread 2.1 (process 18705)] #0 0x0000000000401146 in main () (gdb) inferior [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)] gdb/doc/ChangeLog: * gdb.texinfo (Inferiors Connections and Programs): Document the inferior command when used without argument. gdb/ChangeLog: * NEWS: Add entry for the behavior change of the inferior command. * inferior.c (inferior_command): When no argument is given to the inferior command, display info about the currently selected inferior. gdb/testsuite/ChangeLog: * gdb.base/inferior-noarg.c: New test. * gdb.base/inferior-noarg.exp: New test.
2021-02-02gdb/testsuite: use proc_with_prefix in gdb.base/scope.expSimon Marchi2-5/+9
Fixes: Running /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/scope.exp ... DUPLICATE: gdb.base/scope.exp: print 'scope0.c'::filelocal_ro DUPLICATE: gdb.base/scope.exp: print 'scope0.c'::filelocal_ro DUPLICATE: gdb.base/scope.exp: next gdb/testsuite/ChangeLog: * gdb.base/scope.exp: Use proc_with_prefix. Change-Id: Ic40e24a603da6f2a4f8003b74b2ff3040d2b098d
2021-02-02gdb/testsuite: add test for .debug_{rng,loc}lists section without offset arraySimon Marchi5-13/+164
It is possible for the tables in the .debug_{rng,loc}lists sections to not have an array of offsets. In that case, the offset_entry_count field of the header is 0. The forms DW_FORM_{rng,loc}listx (reference by index) can't be used with that table. Instead, the DW_FORM_sec_offset form, which references a {rng,loc}list by direct offset in the section, must be used. From what I saw, this is what GCC currently produces. Add tests for this case. I didn't see any bug related to this, I just think that it would be nice to have coverage for this. A new `-with-offset-array` option is added to the `table` procs, used when generating {rng,loc}lists, to decide whether to generate the offset array. gdb/testsuite/ChangeLog: * lib/dwarf.exp (rnglists): Add -no-offset-array option to table proc. * gdb.dwarf2/rnglists-sec-offset.exp: Add test for .debug_rnglists table without offset array. * gdb.dwarf2/loclists-sec-offset.exp: Add test for .debug_loclists table without offset array. Change-Id: I8e34a7bf68c9682215ffbbf66600da5b7db91ef7
2021-02-02gdb/dwarf: make read_{loc,rng}list_index return sect_offsetSimon Marchi2-10/+18
I think it's wrong that read_loclist_index and read_rnglist_index return a CORE_ADDR. A CORE_ADDR is an address in the program. These functions return offset in sections (.debug_loclists and .debug_rnglists). I think sect_offset is more appropriate. I'm wondering if struct attribute should have a "set_sect_offset" method, that takes a sect_offset parameter, or if it's better to be left as a simple "unsigned". gdb/ChangeLog: * dwarf2/read.c (read_loclist_index, read_rnglist_index): Return a sect_offset. (read_attribute_reprocess): Adjust. Change-Id: I0e22e0864130fb490072b41ae099762918b8ad4d
2021-02-02gdb/dwarf: split dwarf2_cu::ranges_base in twoSimon Marchi7-85/+251
Consider the test case added in this patch. It defines a compilation unit with a DW_AT_rnglists_base attribute (used for attributes of form DW_FORM_rnglistx), but also uses DW_AT_ranges of form DW_FORM_sec_offset: 0x00000027: DW_TAG_compile_unit DW_AT_ranges [DW_FORM_sec_offset] (0x0000004c [0x0000000000005000, 0x0000000000006000)) DW_AT_rnglists_base [DW_FORM_sec_offset] (0x00000044) The DW_AT_rnglists_base does not play a role in reading the DW_AT_ranges of form DW_FORM_sec_offset, but it should also not do any harm. This case is currently not handled correctly by GDB. This is not something that a compiler is likely to emit, but in my opinion there's no reason why GDB should fail reading it. The problem is that in partial_die_info::read and a few other places where the same logic is replicated, the cu->ranges_base value, containing the DW_AT_rnglists_base value, is wrongfully added to the DW_AT_ranges value. It is quite messy how to decide whether cu->ranges_base should be added to the attribute's value or not. But to summarize, the only time we want to add it is when the attribute comes from a pre-DWARF 5 split unit file (a .dwo) [1]. In this case, the DW_AT_ranges attribute from the split unit file will have form DW_FORM_sec_offset, pointing somewhere in the linked file's .debug_ranges section. *But* it's not a "true" DW_FORM_sec_offset, in that it's an offset relative to the beginning of that CU's contribution in the section, not relative to the beginning of the section. So in that case, and only that case, do we want to add the ranges base value, which we found from the DW_AT_GNU_ranges_base attribute on the skeleton unit. Almost all instances of the DW_AT_ranges attribute will be found in the split unit (on DW_TAG_subprogram, for example), and therefore need to have the ranges base added. However, the DW_TAG_compile_unit DIE in the skeleton may also have a DW_AT_ranges attribute. For that one, the ranges base must not be added. Once the DIEs have been loaded in GDB, however, the distinction between what's coming from the skeleton and what's coming from the split unit is not clear. It is all merged in one big happy tree. So how do we know if a given attribute comes from the split unit or not? We use the fact that in pre-DWARF 5 split DWARF, DW_AT_ranges is found on the skeleton's DW_TAG_compile_unit (in the linked file) and never in the split unit's DW_TAG_compile_unit. This is why you have this in partial_die_info::read: int need_ranges_base = (tag != DW_TAG_compile_unit && attr.form != DW_FORM_rnglistx); However, with the corner case described above (where we have a DW_AT_rnglists_base attribute and a DW_AT_ranges attribute of form DW_FORM_sec_offset) the condition gets it wrong when it encounters an attribute like DW_TAG_subprogram with a DW_AT_ranges attribute of DW_FORM_sec_offset form: it thinks that it is necessary to add the base, when it reality it is not. The problem boils down to failing to differentiate these cases: - a DW_AT_ranges attribute of form DW_FORM_sec_offset in a pre-DWARF 5 split unit (in which case we need to add the base) - a DW_AT_ranges attribute of form DW_FORM_sec_offset in a DWARF 5 non-split unit (in which case we must not add the base) What makes it unnecessarily complex is that the cu->ranges_base field is overloaded, used to hold the pre-DWARF 5, non-standard DW_AT_GNU_ranges_base and the DWARF 5 DW_AT_rnglists_base. In reality, these two are called "bases" but are not the same thing. The result is that we need twisted conditions to try to determine whether or not we should add the base to the attribute's value. To fix it, split the field in two distinct fields. I renamed everything related to the "old" ranges base to "gnu_ranges_base", to make it clear that it's about the non-standard, pre-DWARF 5 thing. And everything related to the DWARF 5 thing gets renamed "rnglists". I think it becomes much easier to reason this way. The issue described above gets fixed by the fact that the DW_AT_rnglists_base value does not end up in cu->gnu_ranges_base, so cu->gnu_ranges_base stays 0. The condition to determine whether gnu_ranges_base should be added can therefore be simplified back to: tag != DW_TAG_compile_unit ... as it was before rnglistx support was added. Extend the gdb.dwarf2/rnglists-sec-offset.exp to cover this case. I also extended the test case for loclists similarly, just to see if there would be some similar problem. There wasn't, but I think it's not a bad idea to test that case for loclists as well, so I left it in the patch. [1] https://gcc.gnu.org/wiki/DebugFission gdb/ChangeLog: * dwarf2/die.h (struct die_info) <ranges_base>: Split in... <gnu_ranges_base>: ... this... <rnglists_base>: ... and this. * dwarf2/read.c (struct dwarf2_cu) <ranges_base>: Split in... <gnu_ranges_base>: ... this... <rnglists_base>: ... and this. (read_cutu_die_from_dwo): Adjust (dwarf2_get_pc_bounds): Adjust (dwarf2_record_block_ranges): Adjust. (read_full_die_1): Adjust (partial_die_info::read): Adjust. (read_rnglist_index): Adjust. gdb/testsuite/ChangeLog: * gdb.dwarf2/rnglists-sec-offset.exp: Add test for DW_AT_ranges of DW_FORM_sec_offset form plus DW_AT_rnglists_base attribute. * gdb.dwarf2/loclists-sec-offset.exp: Add test for DW_AT_location of DW_FORM_sec_offset plus DW_AT_loclists_base attribute Change-Id: Icd109038634b75d0e6e9d7d1dcb62fb9eb951d83
2021-02-02gdb/testsuite: add .debug_loclists testsSimon Marchi6-0/+551
Add tests for the various issues fixed in the previous patches. Add a new "loclists" procedure to the DWARF assembler, to allow generating .debug_loclists sections. gdb/testsuite/ChangeLog: PR gdb/26813 * lib/dwarf.exp (_handle_DW_FORM): Handle DW_FORM_loclistx. (loclists): New proc. * gdb.dwarf2/loclists-multiple-cus.c: New. * gdb.dwarf2/loclists-multiple-cus.exp: New. * gdb.dwarf2/loclists-sec-offset.c: New. * gdb.dwarf2/loclists-sec-offset.exp: New. Change-Id: I209bcb2a9482762ae943e518998d1f7761f76928
2021-02-02gdb/testsuite: DWARF assembler: add context parameters to _locationSimon Marchi2-13/+32
The _location proc is used to assemble a location description. It needs to know some contextual information: - size of an address - size of an offset (into another DWARF section) - DWARF version It currently get all this directly from global variables holding the compilation unit information. This is fine because as of now, all location descriptions are generated in the context of creating a compilation unit. However, a subsequent patch will generate location descriptions while generating a .debug_loclists section. _location should therefore no longer rely on the current compilation unit's properties. Change it to accept these values as parameters instead of accessing the values for the CU. No functional changes intended. gdb/testsuite/ChangeLog: * lib/dwarf.exp (_location): Add parameters. (_handle_DW_FORM): Adjust. Change-Id: Ib94981979c83ffbebac838081d645ad71c221637
2021-02-02gdb/testsuite: add .debug_rnglists testsSimon Marchi4-3/+375
Add tests for the various issues fixed in the previous patches. Add a new "rnglists" procedure to the DWARF assembler, to allow generating .debug_rnglists sections. A trivial change is required to support the DWARF 5 CU header layout. gdb/testsuite/ChangeLog: PR gdb/26813 * lib/dwarf.exp (_handle_DW_FORM): Handle DW_FORM_rnglistx. (cu): Generate header for DWARF 5. (rnglists): New proc. * gdb.dwarf2/rnglists-multiple-cus.exp: New. * gdb.dwarf2/rnglists-sec-offset.exp: New. Change-Id: I5b297e59c370c60cf671dec19796a6c3b9a9f632
2021-02-02gdb/dwarf: read correct rnglist/loclist header in read_{rng,loc}list_indexSimon Marchi2-6/+47
When loading the binary from PR 26813 in GDB, we get: DW_FORM_rnglistx index pointing outside of .debug_rnglists offset array [in module /home/simark/build/binutils-gdb/gdb/MagicPurse] ... and the symbols fail to load. In read_rnglist_index and read_loclist_index, we read the header (documented in sections 7.28 and 7.29 of DWARF 5) of the CU's contribution to the .debug_rnglists / .debug_loclists sections to validate that the index we want to read makes sense. However, we always read the header at the beginning of the section, rather than the header for the contribution from which we want to read the index. To illustrate, here's what the binary from PR 26813 contains. There are two compile units: 0x0000000c: DW_TAG_compile_unit 1 DW_AT_ranges [DW_FORM_rnglistx]: 0x0 DW_AT_rnglists_base [DW_FORM_sec_offset]: 0xC 0x00003ec9: DW_TAG_compile_unit 2 DW_AT_ranges [DW_FORM_rnglistx]: 0xB DW_AT_rnglists_base [DW_FORM_sec_offset]: 0x85 The layout of the .debug_rnglists is the following: [0x00, 0x0B]: header for CU 1's contribution [0x0C, 0x0F]: list of offsets for CU 1 (1 element) [0x10, 0x78]: range lists data for CU 1 [0x79, 0x84]: header for CU 2's contribution [0x85, 0xB4]: list of offsets for CU 2 (12 elements) [0xB5, 0xBD7]: range lists data for CU 2 The DW_AT_rnglists_base attrbute points to the beginning of the list of offsets for that CU, relative to the start of the .debug_rnglists section. That's right after the header for that contribution. When we try to read the DW_AT_ranges attribute for CU 2, read_rnglist_index reads the header for CU 1 instead of the one for CU 2. Since there's only one element in CU 1's offset list, it believes (wrongfully) that the index 0xB is out of range. Fix it by reading the header just before where DW_AT_rnglists_base points to. With this patch, I am able to load GDB built with clang-11 and -gdwarf-5 in itself, with and without -readnow. gdb/ChangeLog: PR gdb/26813 * dwarf2/read.c (read_loclists_rnglists_header): Add header_offset parameter and use it. (read_loclist_index): Read header of the current contribution, not the one at the beginning of the section. (read_rnglist_index): Likewise. Change-Id: Ie53ff8251af8c1556f0a83a31aa8572044b79e3d
2021-02-02gdb/dwarf: few fixes for handling DW_FORM_{rng,loc}listxSimon Marchi4-4/+31
We hit an assertion when loading the binary from PR 26813. When fixing it, execution goes a up bit further but then hits another assert, and another, and another. With these fours fixes, I am able to load the binary and get to the prompt. An error is shown (index pointing outside of the section), because the DW_FORM_rnglistx attribute is not read correctly, but that one is taken care of by the next patch. The four fixes are: - attribute::form_requires_reprocessing needs to handle forms DW_FORM_rnglistx and DW_FORM_loclistx, because set_unsigned_reprocess is called for them in read_attribute_value. - read_attribute_reprocess must call set_unsigned for them, not set_address. The parameter of set_address is a CORE_ADDR, meaning it's for program addresses. Post-reprocess, DW_FORM_rnglistx and DW_FORM_loclistx are offsets into their respective sections (.debug_rnglists and .debug_loclists). set_unsigned is the current attribute value setter that fits the best. But perhaps we should have a setter that takes a sect_offset? - read_attribute_process must call as_unsigned_reprocess instead of as_unsigned to get the pre-reprocess value, otherwise we hit the assert inside as_unsigned that makes sure the attribute doesn't need reprocessing. - attribute::set_unsigned needs to clear the requires_reprocessing flag, otherwise it stays set when reprocessing DW_FORM_rnglistx and DW_FORM_loclistx attributes. There's another assert that we hit once the next patch is applied, but since it's in the same vein as the changes in this patch, I included it in this patch: - attribute::form_is_unsigned must handle form DW_FORM_loclistx, otherwise we hit the assert when trying to call set_unsigned for an attribute of this form. DW_FORM_rnglistx is already handled. gdb/ChangeLog: PR gdb/26813 * dwarf2/attribute.h (struct attribute) <set_unsigned>: Clear requires_reprocessing flag. * dwarf2/attribute.c (attribute::form_is_unsigned): Handle DW_FORM_loclistx. (attribute::form_requires_reprocessing): Handle DW_FORM_rnglistx and DW_FORM_loclistx. * dwarf2/read.c (read_attribute_reprocess): Use set_unsigned instead of set_address for DW_FORM_loclistx and DW_FORM_rnglistx. Change-Id: I06c156fa3913ca98e4e39085f4ef171645b4bc1e
2021-02-02gdb/dwarf: remove unnecessary check in read_{rng,loc}list_indexSimon Marchi2-11/+6
In read_rnglist_index and read_loclist_index, we check that both the start and end of the offset that we read from the offset table are within the section. I think it's unecessary to do both: if the end of the offset is within the section, then surely the start of the offset is within it. Remove the check for the start of the offset in both functions. gdb/ChangeLog: * dwarf2/read.c (read_loclist_index): Remove bound check for start of offset. (read_rnglist_index): Likewise. Change-Id: I7b57ddf4f8a8a28971738f0e3f3af62108f9e19a
2021-02-02gdb/dwarf: add missing bound check to read_loclist_indexSimon Marchi2-4/+18
read_rnglist_index has a bound check to make sure that we don't go past the end of the section while reading the offset, but read_loclist_index doesn't. Add it to read_loclist_index. gdb/ChangeLog: * dwarf2/read.c (read_loclist_index): Add bound check for the end of the offset. Change-Id: Ic4b55c88860fdc3e007740949c78ec84cdb4da60
2021-02-02gdb/dwarf: fix bound check in read_rnglist_indexSimon Marchi2-1/+7
I think this check in read_rnglist_index is wrong: /* Validate that reading won't go beyond the end of the section. */ if (start_offset + cu->header.offset_size > rnglist_base + section->size) error (_("Reading DW_FORM_rnglistx index beyond end of" ".debug_rnglists section [in module %s]"), objfile_name (objfile)); The addition `rnglist_base + section->size` doesn't make sense. rnglist_base is an offset into `section`, so it doesn't make sense to add it to `section`'s size. `start_offset` also is an offset into `section`, so we should just compare it to just `section->size`. gdb/ChangeLog: * dwarf2/read.c (read_rnglist_index): Fix bound check. Change-Id: If0ff7c73f4f80f79aac447518f4e8f131f2db8f2
2021-02-02gdb/dwarf: change read_loclist_index complaints into errorsSimon Marchi2-8/+16
Unlike read_rnglists_index, read_loclist_index uses complaints when it detects an inconsistency (a DW_FORM_loclistx value without a .debug_loclists section or an offset outside of the section). I really think they should be errors, since there's no point in continuing if this situation happens, we will likely segfault or read garbage. gdb/ChangeLog: * dwarf2/read.c (read_loclist_index): Change complaints into errors. Change-Id: Ic3a1cf6e682d47cb6e739dd76fd7ca5be2637e10
2021-02-02readelf: Add 'R' and 'D' to "Key to Flags:"H.J. Lu3-0/+21
Add "R (retain)" and "D (mbind)" to "Key to Flags:". PR binutils/27281 * readelf.c (process_section_headers): Add 'R' and 'D' to "Key to Flags:". * testsuite/binutils-all/retain1a.d: Updated.
2021-02-02PR27311, ld.bfd (symbol from plugin): undefined referenceAlan Modra9-13/+60
A default versioned symbol definition in a shared library is overridden by an unversioned definition in a regular object file, and thus should not be reason to make an as-needed library needed. bfd/ PR 27311 * elflink.c (_bfd_elf_add_default_symbol): Add override parameter. Use when handling default versioned symbol. Rename existing override variable to nondef_override and use for non-default versioned symbol. (elf_link_add_object_symbols): Adjust call to suit. Don't pull in as-needed libraries when override is set. ld/ * testsuite/ld-plugin/pr27311.d, * testsuite/ld-plugin/pr27311.ver, * testsuite/ld-plugin/pr27311a.c, * testsuite/ld-plugin/pr27311b.c, * testsuite/ld-plugin/pr27311c.c: New testcase. * testsuite/ld-plugin/lto.exp: Run it. Correct PR14918 and PR12982 entries.
2021-02-02[gdb/symtab] Fix assert in write_one_signatured_typeTom de Vries4-0/+34
When running test-case gdb.dwarf2/fission-reread.exp with target board cc-with-gdb-index, we run into an abort during the generation of the gdb-index by cc-with-tweaks.sh: ... build/gdb/testsuite/cache/gdb.sh: line 1: 27275 Aborted (core dumped) ... This can be reproduced on the command line like this: ... $ gdb -batch ./outputs/gdb.dwarf2/fission-reread/fission-reread \ -ex 'save gdb-index ./outputs/gdb.dwarf2/fission-reread' warning: Could not find DWO TU fission-reread.dwo(0x9022f1ceac7e8b19) \ referenced by TU at offset 0x0 [in module fission-reread] warning: Could not find DWO CU fission-reread.dwo(0x807060504030201) \ referenced by CU at offset 0x561 [in module fission-reread] Aborted (core dumped) ... The abort is a segfault due to a using a nullptr psymtab in write_one_signatured_type. The problem is that we're trying to write index entries for the type unit with signature: ... (gdb) p /x entry->signature $2 = 0x9022f1ceac7e8b19 ... which is a skeleton type unit: ... Contents of the .debug_types section: Compilation Unit @ offset 0x0: Length: 0x4a (32-bit) Version: 4 Abbrev Offset: 0x165 Pointer Size: 4 Signature: 0x9022f1ceac7e8b19 Type Offset: 0x0 <0><17>: Abbrev Number: 2 (DW_TAG_type_unit) <18> DW_AT_comp_dir : /tmp/src/gdb/testsuite <2f> DW_AT_GNU_dwo_name: fission-reread.dwo <42> DW_AT_GNU_pubnames: 0x0 <46> DW_AT_GNU_pubtypes: 0x0 <4a> DW_AT_GNU_addr_base: 0x0 ... referring to a .dwo file, but as the warnings show, the .dwo file is not found. Fix this by skipping the type unit in write_one_signatured_type if psymtab == nullptr. Tested on x86_64-linux. gdb/ChangeLog: 2021-02-02 Tom de Vries <tdevries@suse.de> PR symtab/24620 * dwarf2/index-write.c (write_one_signatured_type): Skip if psymtab == nullptr. gdb/testsuite/ChangeLog: 2021-02-02 Tom de Vries <tdevries@suse.de> PR symtab/24620 * gdb.dwarf2/fission-reread.exp: Add test-case.
2021-02-02Automatic date update in version.inGDB Administrator1-1/+1
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