[Lldb-commits] [PATCH] D103172: [lldb][NFC] Allow range-based for loops over DWARFDIE's children

Wed Aug 4 01:09:23 PDT 2021

wallace added subscribers: clayborg, wallace.
wallace added a comment.

This breaks debugging in many cases :( Many of my users started reporting crashes in LLDB when setting source line breakpoints.

For example, a simple command like `(lldb) b TransAttr.cpp:758` causes a crash and has the following stack trace

  thread #1, name = 'lldb', stop reason = signal SIGSEGV: invalid address (fault address: 0x10)
   * frame #0: 0x00007f1c2b642caa liblldb.so.14`DWARFUnit::GetSymbolFileDWARF(this=0x0000000000000000) const at DWARFUnit.h:194:56
     frame #1: 0x00007f1c2bd46ce4 liblldb.so.14`SymbolFileDWARF::GetTypeSystem(unit=0x0000000000000000) at SymbolFileDWARF.cpp:3880:15
     frame #2: 0x00007f1c2bd3b29b liblldb.so.14`SymbolFileDWARF::GetDWARFParser(unit=0x0000000000000000) at SymbolFileDWARF.cpp:3884:29
     frame #3: 0x00007f1c2bd8cb87 liblldb.so.14`DWARFASTParserClang::CopyUniqueClassMethodTypes(this=0x0000000001eaa920, src_class_die=0x00007ffe9ff0ff38, dst_class_die=0x00007ffe9ff0fe48, class_type=0x0000000001d42c10, failures=size=0) at DWARFASTParserClang.cpp:3572:11
     frame #4: 0x00007f1c2bd891fd liblldb.so.14`DWARFASTParserClang::ParseSubroutine(this=0x0000000001eaa920, die=0x00007ffe9ff10778, attrs=0x00007ffe9ff101b0) at DWARFASTParserClang.cpp:1025:15
     frame #5: 0x00007f1c2bd85080 liblldb.so.14`DWARFASTParserClang::ParseTypeFromDWARF(this=0x0000000001eaa920, sc=0x00007ffe9ff105d0, die=0x00007ffe9ff10778, type_is_new_ptr=0x0000000000000000) at DWARFASTParserClang.cpp:522:15
     frame #6: 0x00007f1c2bd401fb liblldb.so.14`SymbolFileDWARF::ParseType(this=0x00000000004610a0, sc=0x00007ffe9ff105d0, die=0x00007ffe9ff10778, type_is_new_ptr=0x0000000000000000) at SymbolFileDWARF.cpp:2946:31
     frame #7: 0x00007f1c2bd3b70f liblldb.so.14`SymbolFileDWARF::GetTypeForDIE(this=0x00000000004610a0, die=0x00007ffe9ff10778, resolve_function_context=false) at SymbolFileDWARF.cpp:2560:17
     frame #8: 0x00007f1c2bd3a4bd liblldb.so.14`SymbolFileDWARF::ResolveType(this=0x00000000004610a0, die=0x00007ffe9ff10778, assert_not_being_parsed=true, resolve_function_context=false) at SymbolFileDWARF.cpp:1568:18
     frame #9: 0x00007f1c2bd17500 liblldb.so.14`DWARFDIE::ResolveType(this=0x00007ffe9ff10778) const at DWARFDIE.cpp:350:24
     frame #10: 0x00007f1c2bd3a365 liblldb.so.14`SymbolFileDWARF::ResolveTypeUID(this=0x00000000004610a0, type_uid=57283337) at SymbolFileDWARF.cpp:1437:21
     frame #11: 0x00007f1c2b73037e liblldb.so.14`lldb_private::Function::GetType(this=0x0000000001cd5ed0) at Function.cpp:515:24
     frame #12: 0x00007f1c2b73017a liblldb.so.14`lldb_private::Function::GetStartLineSourceInfo(this=0x0000000001cd5ed0, source_file=0x00007ffe9ff109e0, line_no=0x00007ffe9ff109dc) at Function.cpp:252:3
     frame #13: 0x00007f1c2b515a5e liblldb.so.14`lldb_private::BreakpointResolverFileLine::FilterContexts(this=0x0000000001f61c00, sc_list=0x00007ffe9ff10d00, is_relative=true) at BreakpointResolverFileLine.cpp:162:20
     frame #14: 0x00007f1c2b5163d3 liblldb.so.14`lldb_private::BreakpointResolverFileLine::SearchCallback(this=0x0000000001f61c00, filter=0x0000000001fab770, context=0x00007ffe9ff10d68, addr=0x0000000000000000) at BreakpointResolverFileLine.cpp:254:3
     frame #15: 0x00007f1c2b5cae2a liblldb.so.14`lldb_private::SearchFilter::DoModuleIteration(this=0x0000000001fab770, context=0x00007ffe9ff10f28, searcher=0x0000000001f61c00) at SearchFilter.cpp:271:20
     frame #16: 0x00007f1c2b5cabb9 liblldb.so.14`lldb_private::SearchFilter::Search(this=0x0000000001fab770, searcher=0x0000000001f61c00) at SearchFilter.cpp:216:3
     frame #17: 0x00007f1c2b50c24e liblldb.so.14`lldb_private::BreakpointResolver::ResolveBreakpoint(this=0x0000000001f61c00, filter=0x0000000001fab770) at BreakpointResolver.cpp:177:10
     frame #18: 0x00007f1c2b4e93e6 liblldb.so.14`lldb_private::Breakpoint::ResolveBreakpoint(this=0x00000000003c76d0) at Breakpoint.cpp:443:20
     frame #19: 0x00007f1c2b851596 liblldb.so.14`lldb_private::Target::AddBreakpoint(this=0x000000000044dad0, bp_sp=std::__shared_ptr<lldb_private::Breakpoint, __gnu_cxx::_S_atomic>::element_type @ 0x00000000003c76d0, internal=false) at Target.cpp:662:10
     frame #20: 0x00007f1c2b852f64 liblldb.so.14`lldb_private::Target::CreateBreakpoint(this=0x000000000044dad0, filter_sp=std::__shared_ptr<lldb_private::SearchFilter, __gnu_cxx::_S_atomic>::element_type @ 0x0000000001fab770, resolver_sp=std::__shared_ptr<lldb_private::BreakpointResolver, __gnu_cxx::_S_atomic>::element_type @ 0x0000000001f61c00, internal=false, request_hardware=false, resolve_indirect_symbols=true) at Target.cpp:641:5
     frame #21: 0x00007f1c2b85342f liblldb.so.14`lldb_private::Target::CreateBreakpoint(this=0x000000000044dad0, containingModules=0x0000000000348b80, file=0x00007ffe9ff11768, line_no=758, column=0, offset=0, check_inlines=eLazyBoolYes, skip_prologue=eLazyBoolYes, internal=false, hardware=false, move_to_nearest_code=eLazyBoolYes) at Target.cpp:384:10
     frame #22: 0x00007f1c2d6895f0 liblldb.so.14`CommandObjectBreakpointSet::DoExecute(this=0x0000000000348750, command=0x00007ffe9ff11908, result=0x00007ffe9ff123f8) at CommandObjectBreakpoint.cpp:581:22
     frame #23: 0x00007f1c2b6cfed4 liblldb.so.14`lldb_private::CommandObjectParsed::Execute(this=0x0000000000348750, args_string="--file 'TransAttr.cpp' --line 758", result=0x00007ffe9ff123f8) at CommandObject.cpp:995:19
     frame #24: 0x00007f1c2b6a5062 liblldb.so.14`lldb_private::CommandInterpreter::HandleCommand(this=0x0000000000333650, command_line="breakpoint set --file 'TransAttr.cpp' --line 758", lazy_add_to_history=eLazyBoolCalculate, result=0x00007ffe9ff123f8) at CommandInterpreter.cpp:1804:14
     frame #25: 0x00007f1c2d700897 liblldb.so.14`lldb_private::CommandObjectRegexCommand::DoExecute(this=0x000000000038ab60, command=(Data = "TransAttr.cpp:758", Length = 17), result=0x00007ffe9ff123f8) at CommandObjectRegexCommand.cpp:56:28
     frame #26: 0x00007f1c2b6d0125 liblldb.so.14`lldb_private::CommandObjectRaw::Execute(this=0x000000000038ab60, args_string="TransAttr.cpp:758", result=0x00007ffe9ff123f8) at CommandObject.cpp:1017:17
     frame #27: 0x00007f1c2b6a5062 liblldb.so.14`lldb_private::CommandInterpreter::HandleCommand(this=0x0000000000333650, command_line="b TransAttr.cpp:758", lazy_add_to_history=eLazyBoolCalculate, result=0x00007ffe9ff123f8) at CommandInterpreter.cpp:1804:14
     frame #28: 0x00007f1c2b6a9a7f liblldb.so.14`lldb_private::CommandInterpreter::IOHandlerInputComplete(this=0x0000000000333650, io_handler=0x0000000001f44ee0, line=error: summary string parsing error) at CommandInterpreter.cpp:2848:3
     frame #29: 0x00007f1c2b5799de liblldb.so.14`lldb_private::IOHandlerEditline::Run(this=0x0000000001f44ee0) at IOHandler.cpp:579:22
     frame #30: 0x00007f1c2b53c323 liblldb.so.14`lldb_private::Debugger::RunIOHandlers(this=0x0000000000331ca0) at Debugger.cpp:877:16
     frame #31: 0x00007f1c2b6ab353 liblldb.so.14`lldb_private::CommandInterpreter::RunCommandInterpreter(this=0x0000000000333650, options=0x00007ffe9ff12750) at CommandInterpreter.cpp:3094:16
     frame #32: 0x00007f1c2aea5281 liblldb.so.14`lldb::SBDebugger::RunCommandInterpreter(this=0x00007ffe9ff12bd0, auto_handle_events=true, spawn_thread=false) at SBDebugger.cpp:1214:42
     frame #33: 0x000000000022c48e lldb`Driver::MainLoop(this=0x00007ffe9ff12bb0) at Driver.cpp:676:18
     frame #34: 0x000000000022d1c1 lldb`main(argc=2, argv=0x00007ffe9ff131c8) at Driver.cpp:944:26
     frame #35: 0x00007f1c266ddd95 libc.so.6`__libc_start_main(main=(lldb`main at Driver.cpp:870), argc=2, argv=0x00007ffe9ff131c8, init=<unavailable>, fini=<unavailable>, rtld_fini=<unavailable>, stack_end=0x00007ffe9ff131b8) at libc-start.c:308:16
     frame #36: 0x000000000022894a lldb`_start at start.S:120

An interesting part is frame 3:

  (lldb) frame select 3
  frame #3: 0x00007f1c2bd8cb87 liblldb.so.14`DWARFASTParserClang::CopyUniqueClassMethodTypes(this=0x0000000001eaa920, src_class_die=0x00007ffe9ff0ff38, dst_class_die=0x00007ffe9ff0fe48, class_type=0x0000000001d42c10, failures=size=0) at DWARFASTParserClang.cpp:3572:11
     3569
     3570   DWARFASTParserClang *src_dwarf_ast_parser =
     3571       static_cast<DWARFASTParserClang *>(
  -> 3572           SymbolFileDWARF::GetDWARFParser(*src_die.GetCU()));
     3573   DWARFASTParserClang *dst_dwarf_ast_parser =
     3574       static_cast<DWARFASTParserClang *>(
     3575           SymbolFileDWARF::GetDWARFParser(*dst_die.GetCU()));
  (lldb) p src_die
  (DWARFDIE) $0 = {
    DWARFBaseDIE = {
      m_cu = nullptr
      m_die = nullptr
    }
  }

This makes me think that at some points the iterator is leaking invalid DIEs. Reverting this diff fixes the issues locally. So I think we should revert this until we can make a more stable patch.

cc: @clayborg

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103172/new/

https://reviews.llvm.org/D103172