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Mark all Swift-specific changes in Breakpoint with comments. NFC #54

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merged 1 commit into from Oct 30, 2019
Merged

Mark all Swift-specific changes in Breakpoint with comments. NFC #54

merged 1 commit into from Oct 30, 2019

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This is to facilitate identifying divergences and thus encourage
upstreaming them and/or make merge conflict resolutions more obvious.

@adrian-prantl
Mark all Swift-specific changes in Breakpoint with comments. NFC
abf345c 
This is to facilitate identifying divergences and thus encourage
upstreaming them and/or make merge conflict resolutions more obvious.
dcci
dcci approved these changes Oct 30, 2019
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LGTM

@adrian-prantl adrian-prantl merged commit fb817ba into apple:swift/master-next Oct 30, 2019
swift-ci pushed a commit that referenced this pull request Dec 8, 2019
@sylvestre
Fix typo in the AST Matcher Reference doc Closes: #54
a05d7c2
@adrian-prantl adrian-prantl mentioned this pull request Jul 20, 2020
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@trfiala trfiala mannequin mentioned this pull request Jul 21, 2016
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@swift-ci swift-ci mentioned this pull request May 7, 2022
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adrian-prantl added a commit to adrian-prantl/llvm-project that referenced this pull request Jan 20, 2023
@adrian-prantl
Work around an infinite recursion with deadlock that only exists on
ba81700 
the swift branch.

The function IRExecutionUnit::PopulateSymtab() is only implemented in swift-lldb.

One thing it does is resolve any unresolved global symbols in the JIT
module. This global search can cause the JIT module to recursively be
asked for its symtab.

This patch works around the problem by removing the JIT module from
the list of modules being searched while in PopulateSymtab. That isn't
done in the most elegant fashion, as it does so by changing the state
of the IRExecutionUnit object.

(lldb) bt
* thread apple#2, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    frame #0: 0x00007ff80dc2a0ce libsystem_kernel.dylib`__psynch_cvwait + 10
    frame apple#1: 0x00007ff80dc66758 libsystem_pthread.dylib`_pthread_cond_wait + 1242
    frame apple#2: 0x00007ff80dba51fd libc++.1.dylib`std::__1::__call_once(unsigned long volatile&, void*, void (*)(void*)) + 70
    frame apple#3: 0x000000014ff9235d LLDB`lldb_private::ObjectFile::GetSymtab() at mutex:676:9 [opt]
  * frame apple#4: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab() [inlined] void llvm::call_once<lldb_private::ObjectFile::GetSymtab()::$_0>(flag=<unavailable>, F=<unavailable>)::$_0&&) at Threading.h:89:5 [opt]
    frame apple#5: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab(this=0x0000600003d04f18) at ObjectFile.cpp:758:5 [opt]
    frame apple#6: 0x0000000150531d67 LLDB`SymbolFileSymtab::CalculateAbilities(this=0x0000600003e20600) at SymbolFileSymtab.cpp:60:42 [opt]
    frame apple#7: 0x000000015053001d LLDB`lldb_private::SymbolFileCommon::GetAbilities(this=0x0000600003e20600) at SymbolFile.h:478:21 [opt]
    frame apple#8: 0x000000014ff9a8cd LLDB`lldb_private::SymbolFile::FindPlugin(objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolFile.cpp:71:62 [opt]
    frame apple#9: 0x000000014ff9f4bd LLDB`lldb_private::SymbolVendor::AddSymbolFileRepresentation(this=0x00006000002b05a0, objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolVendor.cpp:71:27 [opt]
    frame apple#10: 0x000000014ff9f419 LLDB`lldb_private::SymbolVendor::FindPlugin(module_sp=std::__1::shared_ptr<lldb_private::Module>::element_type @ 0x0000000106589ca0 strong=12 weak=26, feedback_strm=0x0000000000000000) at SymbolVendor.cpp:57:16 [opt]
    frame apple#11: 0x000000014fe8d2a0 LLDB`lldb_private::Module::GetSymbolFile(this=0x0000000106589ca0, can_create=<unavailable>, feedback_strm=0x0000000000000000) at Module.cpp:1083:13 [opt]
    frame apple#12: 0x000000014fe8c4c0 LLDB`lldb_private::Module::FindFunctions(lldb_private::ConstString, lldb_private::CompilerDeclContext const&, lldb::FunctionNameType, lldb_private::ModuleFunctionSearchOptions const&, lldb_private::SymbolContextList&) at Module.cpp:857:29 [opt]
    frame apple#13: 0x000000014fe8c4b0 LLDB`lldb_private::Module::FindFunctions(this=0x0000000106589ca0, name=<unavailable>, parent_decl_ctx=0x00007ff7bfef98d0, name_type_mask=eFunctionNameTypeFull, options=0x00007ff7bfef9990, sc_list=0x00007ff7bfef9960) at Module.cpp:878:3 [opt]
    frame apple#14: 0x000000014fe92ba1 LLDB`lldb_private::ModuleList::FindFunctions(this=<unavailable>, name=<unavailable>, name_type_mask=<unavailable>, options=0x00007ff7bfef9990, sc_list=0x00007ff7bfef9960) const at ModuleList.cpp:554:18 [opt]
    frame apple#15: 0x000000014fef36cb LLDB`lldb_private::IRExecutionUnit::FindInSymbols(this=<unavailable>, names=<unavailable>, sc=0x00000001004db950, symbol_was_missing_weak=<unavailable>) at IRExecutionUnit.cpp:843:33 [opt]
    frame apple#16: 0x000000014fef3c36 LLDB`lldb_private::IRExecutionUnit::FindSymbol(this=0x00000001004db860, name=<unavailable>, missing_weak=0x00007ff7bfef9a97) at IRExecutionUnit.cpp:915:22 [opt]
    frame apple#17: 0x000000014fef43f3 LLDB`lldb_private::IRExecutionUnit::MemoryManager::GetSymbolAddressAndPresence(this=0x0000000107c71000, Name="_$sBoWV", missing_weak=0x00007ff7bfef9a97) at IRExecutionUnit.cpp:1010:31 [opt]
    frame apple#18: 0x000000014fef4490 LLDB`non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) [inlined] lldb_private::IRExecutionUnit::MemoryManager::findSymbol(this=<unavailable>, Name=<unavailable>) at IRExecutionUnit.cpp:988:21 [opt]
    frame apple#19: 0x000000014fef447d LLDB`non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) at IRExecutionUnit.cpp:0 [opt]
    frame apple#20: 0x0000000154ab3a5c LLDB`llvm::LinkingSymbolResolver::findSymbol(this=0x0000000107e0ecc0, Name="_$sBoWV") at MCJIT.cpp:681:26 [opt]
    frame apple#21: 0x0000000154abd458 LLDB`llvm::LegacyJITSymbolResolver::lookup(this=<unavailable>, Symbols=<unavailable>, OnResolved=<unavailable>)>) at JITSymbol.cpp:125:22 [opt]
    frame apple#22: 0x0000000154abf6f3 LLDB`llvm::RuntimeDyldImpl::resolveExternalSymbols(this=0x000000013cfeea20) at RuntimeDyld.cpp:1195:16 [opt]
    frame apple#23: 0x0000000154abecde LLDB`llvm::RuntimeDyldImpl::resolveRelocations(this=0x000000013cfeea20) at RuntimeDyld.cpp:131:18 [opt]
    frame apple#24: 0x0000000154ab1482 LLDB`llvm::MCJIT::finalizeLoadedModules(this=0x0000000107e0ea00) at MCJIT.cpp:242:8 [opt]
    frame apple#25: 0x0000000154ab24ec LLDB`llvm::MCJIT::getGlobalValueAddress(this=0x0000000107e0ea00, Name=<unavailable>) at MCJIT.cpp:400:5 [opt]
    frame apple#26: 0x000000014fef499d LLDB`lldb_private::IRExecutionUnit::PopulateSymtab(this=0x00000001004db860, obj_file=<unavailable>, symtab=0x0000600003342f80) at IRExecutionUnit.cpp:1246:34 [opt]
    frame apple#27: 0x00000001503e4bf1 LLDB`ObjectFileJIT::ParseSymtab(this=0x0000600003d04f18, symtab=0x0000600003342f80) at ObjectFileJIT.cpp:112:18 [opt]
    frame apple#28: 0x000000014ff93a14 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) at ObjectFile.cpp:764:9 [opt]
    frame apple#29: 0x000000014ff93998 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) [inlined] decltype(__f=0x00007ff7bfefa180)::$_0>(fp)()) std::__1::__invoke<lldb_private::ObjectFile::GetSymtab()::$_0>(lldb_private::ObjectFile::GetSymtab()::$_0&&) at type_traits:3918:1 [opt]
    frame apple#30: 0x000000014ff93998 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) [inlined] void std::__1::__call_once_param<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >::__execute<>(this=<unavailable>, (null)=<unavailable>) at mutex:630:9 [opt]
    frame apple#31: 0x000000014ff93984 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) [inlined] std::__1::__call_once_param<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >::operator(this=<unavailable>)() at mutex:622:9 [opt]
    frame apple#32: 0x000000014ff93984 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(__vp=<unavailable>) at mutex:658:5 [opt]
    frame apple#33: 0x00007ff80dba5242 libc++.1.dylib`std::__1::__call_once(unsigned long volatile&, void*, void (*)(void*)) + 139
    frame apple#34: 0x000000014ff9235d LLDB`lldb_private::ObjectFile::GetSymtab() at mutex:676:9 [opt]
    frame apple#35: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab() [inlined] void llvm::call_once<lldb_private::ObjectFile::GetSymtab()::$_0>(flag=<unavailable>, F=<unavailable>)::$_0&&) at Threading.h:89:5 [opt]
    frame apple#36: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab(this=0x0000600003d04f18) at ObjectFile.cpp:758:5 [opt]
    frame apple#37: 0x0000000150531d67 LLDB`SymbolFileSymtab::CalculateAbilities(this=0x0000600003e20100) at SymbolFileSymtab.cpp:60:42 [opt]
    frame apple#38: 0x000000015053001d LLDB`lldb_private::SymbolFileCommon::GetAbilities(this=0x0000600003e20100) at SymbolFile.h:478:21 [opt]
    frame apple#39: 0x000000014ff9a8cd LLDB`lldb_private::SymbolFile::FindPlugin(objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolFile.cpp:71:62 [opt]
    frame apple#40: 0x000000014ff9f4bd LLDB`lldb_private::SymbolVendor::AddSymbolFileRepresentation(this=0x00006000002b0560, objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolVendor.cpp:71:27 [opt]
    frame apple#41: 0x000000014ff9f419 LLDB`lldb_private::SymbolVendor::FindPlugin(module_sp=std::__1::shared_ptr<lldb_private::Module>::element_type @ 0x0000000106589ca0 strong=12 weak=26, feedback_strm=0x0000000000000000) at SymbolVendor.cpp:57:16 [opt]
    frame apple#42: 0x000000014fe8d2a0 LLDB`lldb_private::Module::GetSymbolFile(this=0x0000000106589ca0, can_create=<unavailable>, feedback_strm=0x0000000000000000) at Module.cpp:1083:13 [opt]
    frame apple#43: 0x000000015041f366 LLDB`lldb_private::PlatformDarwin::LocateExecutableScriptingResources(this=<unavailable>, target=0x000000010309e800, module=0x0000000106589ca0, feedback_stream=0x00007ff7bfefa770) at PlatformDarwin.cpp:212:40 [opt]
    frame apple#44: 0x000000014fe8f97c LLDB`lldb_private::Module::LoadScriptingResourceInTarget(this=<unavailable>, target=0x000000010309e800, error=0x00007ff7bfefa750, feedback_stream=<unavailable>) at Module.cpp:1588:44 [opt]
    frame apple#45: 0x0000000150027520 LLDB`lldb_private::Target::ModulesDidLoad(lldb_private::ModuleList&) [inlined] LoadScriptingResourceForModule(module_sp=<unavailable>, target=0x000000010309e800) at Target.cpp:1415:32 [opt]
    frame apple#46: 0x00000001500274f4 LLDB`lldb_private::Target::ModulesDidLoad(this=0x000000010309e800, module_list=<unavailable>) at Target.cpp:1672:7 [opt]
    frame apple#47: 0x00000001500284ca LLDB`non-virtual thunk to lldb_private::Target::NotifyModuleAdded(lldb_private::ModuleList const&, std::__1::shared_ptr<lldb_private::Module> const&) at Target.cpp:1637:5 [opt]
    frame apple#48: 0x00000001500284a7 LLDB`non-virtual thunk to lldb_private::Target::NotifyModuleAdded(lldb_private::ModuleList const&, std::__1::shared_ptr<lldb_private::Module> const&) at Target.cpp:0 [opt]
    frame apple#49: 0x000000014fe91f8b LLDB`lldb_private::ModuleList::Append(std::__1::shared_ptr<lldb_private::Module> const&, bool) at ModuleList.cpp:334:19 [opt]
    frame apple#50: 0x000000014fe91f44 LLDB`lldb_private::ModuleList::Append(this=0x000000010309eb48, module_sp=std::__1::shared_ptr<lldb_private::Module>::element_type @ 0x0000000106589ca0 strong=12 weak=26, notify=<unavailable>) at ModuleList.cpp:339:3 [opt]
    frame apple#51: 0x000000014fef5200 LLDB`lldb_private::IRExecutionUnit::CreateJITModule(this=<unavailable>, name="$__lldb_expr2") at IRExecutionUnit.cpp:1339:27 [opt]
    frame apple#52: 0x000000015011063b LLDB`lldb_private::SwiftUserExpression::Parse(this=<unavailable>, diagnostic_manager=<unavailable>, exe_ctx=<unavailable>, execution_policy=eExecutionPolicyOnlyWhenNeeded, keep_result_in_memory=<unavailable>, generate_debug_info=<unavailable>) at SwiftUserExpression.cpp:802:28 [opt]
    frame apple#53: 0x000000014ff0cd05 LLDB`lldb_private::UserExpression::Evaluate(exe_ctx=<unavailable>, options=0x00006000033441e0, expr="", prefix="", result_valobj_sp=nullptr, error=0x00007ff7bfefaf40, fixed_expression=Summary Unavailable, ctx_obj=0x0000000000000000) at UserExpression.cpp:281:27 [opt]
    frame apple#54: 0x000000015002e124 LLDB`lldb_private::Target::EvaluateExpression(this=0x000000010309e800, expr="", exe_scope=<unavailable>, result_valobj_sp=nullptr, options=<unavailable>, fixed_expression=Summary Unavailable, ctx_obj=0x0000000000000000) at Target.cpp:2960:25 [opt]
    frame apple#55: 0x000000014fcc3e62 LLDB`lldb::SBFrame::EvaluateExpression(this=<unavailable>, expr=<unavailable>, options=0x0000600000011880) at SBFrame.cpp:1084:17 [opt]
    frame apple#56: 0x000000014fdaaf70 LLDB`_wrap_SBFrame_EvaluateExpression(_object*, _object*) at LLDBWrapPython.cpp:32887:22 [opt]
    frame apple#57: 0x000000014fdaaebf LLDB`_wrap_SBFrame_EvaluateExpression(self=<unavailable>, args=<unavailable>) at LLDBWrapPython.cpp:32933:18 [opt]
adrian-prantl added a commit to adrian-prantl/llvm-project that referenced this pull request Jan 20, 2023
@adrian-prantl
Work around an infinite recursion with deadlock that only exists on
a8339d3 
the swift branch.

The function IRExecutionUnit::PopulateSymtab() is only implemented in swift-lldb.

One thing it does is resolve any unresolved global symbols in the JIT
module. This global search can cause the JIT module to recursively be
asked for its symtab.

This patch works around the problem by removing the JIT module from
the list of modules being searched while in PopulateSymtab. That isn't
done in the most elegant fashion, as it does so by changing the state
of the IRExecutionUnit object.

(lldb) bt
* thread apple#2, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    frame #0: 0x00007ff80dc2a0ce libsystem_kernel.dylib`__psynch_cvwait + 10
    frame apple#1: 0x00007ff80dc66758 libsystem_pthread.dylib`_pthread_cond_wait + 1242
    frame apple#2: 0x00007ff80dba51fd libc++.1.dylib`std::__1::__call_once(unsigned long volatile&, void*, void (*)(void*)) + 70
    frame apple#3: 0x000000014ff9235d LLDB`lldb_private::ObjectFile::GetSymtab() at mutex:676:9 [opt]
  * frame apple#4: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab() [inlined] void llvm::call_once<lldb_private::ObjectFile::GetSymtab()::$_0>(flag=<unavailable>, F=<unavailable>)::$_0&&) at Threading.h:89:5 [opt]
    frame apple#5: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab(this=0x0000600003d04f18) at ObjectFile.cpp:758:5 [opt]
    frame apple#6: 0x0000000150531d67 LLDB`SymbolFileSymtab::CalculateAbilities(this=0x0000600003e20600) at SymbolFileSymtab.cpp:60:42 [opt]
    frame apple#7: 0x000000015053001d LLDB`lldb_private::SymbolFileCommon::GetAbilities(this=0x0000600003e20600) at SymbolFile.h:478:21 [opt]
    frame apple#8: 0x000000014ff9a8cd LLDB`lldb_private::SymbolFile::FindPlugin(objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolFile.cpp:71:62 [opt]
    frame apple#9: 0x000000014ff9f4bd LLDB`lldb_private::SymbolVendor::AddSymbolFileRepresentation(this=0x00006000002b05a0, objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolVendor.cpp:71:27 [opt]
    frame apple#10: 0x000000014ff9f419 LLDB`lldb_private::SymbolVendor::FindPlugin(module_sp=std::__1::shared_ptr<lldb_private::Module>::element_type @ 0x0000000106589ca0 strong=12 weak=26, feedback_strm=0x0000000000000000) at SymbolVendor.cpp:57:16 [opt]
    frame apple#11: 0x000000014fe8d2a0 LLDB`lldb_private::Module::GetSymbolFile(this=0x0000000106589ca0, can_create=<unavailable>, feedback_strm=0x0000000000000000) at Module.cpp:1083:13 [opt]
    frame apple#12: 0x000000014fe8c4c0 LLDB`lldb_private::Module::FindFunctions(lldb_private::ConstString, lldb_private::CompilerDeclContext const&, lldb::FunctionNameType, lldb_private::ModuleFunctionSearchOptions const&, lldb_private::SymbolContextList&) at Module.cpp:857:29 [opt]
    frame apple#13: 0x000000014fe8c4b0 LLDB`lldb_private::Module::FindFunctions(this=0x0000000106589ca0, name=<unavailable>, parent_decl_ctx=0x00007ff7bfef98d0, name_type_mask=eFunctionNameTypeFull, options=0x00007ff7bfef9990, sc_list=0x00007ff7bfef9960) at Module.cpp:878:3 [opt]
    frame apple#14: 0x000000014fe92ba1 LLDB`lldb_private::ModuleList::FindFunctions(this=<unavailable>, name=<unavailable>, name_type_mask=<unavailable>, options=0x00007ff7bfef9990, sc_list=0x00007ff7bfef9960) const at ModuleList.cpp:554:18 [opt]
    frame apple#15: 0x000000014fef36cb LLDB`lldb_private::IRExecutionUnit::FindInSymbols(this=<unavailable>, names=<unavailable>, sc=0x00000001004db950, symbol_was_missing_weak=<unavailable>) at IRExecutionUnit.cpp:843:33 [opt]
    frame apple#16: 0x000000014fef3c36 LLDB`lldb_private::IRExecutionUnit::FindSymbol(this=0x00000001004db860, name=<unavailable>, missing_weak=0x00007ff7bfef9a97) at IRExecutionUnit.cpp:915:22 [opt]
    frame apple#17: 0x000000014fef43f3 LLDB`lldb_private::IRExecutionUnit::MemoryManager::GetSymbolAddressAndPresence(this=0x0000000107c71000, Name="_$sBoWV", missing_weak=0x00007ff7bfef9a97) at IRExecutionUnit.cpp:1010:31 [opt]
    frame apple#18: 0x000000014fef4490 LLDB`non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) [inlined] lldb_private::IRExecutionUnit::MemoryManager::findSymbol(this=<unavailable>, Name=<unavailable>) at IRExecutionUnit.cpp:988:21 [opt]
    frame apple#19: 0x000000014fef447d LLDB`non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) at IRExecutionUnit.cpp:0 [opt]
    frame apple#20: 0x0000000154ab3a5c LLDB`llvm::LinkingSymbolResolver::findSymbol(this=0x0000000107e0ecc0, Name="_$sBoWV") at MCJIT.cpp:681:26 [opt]
    frame apple#21: 0x0000000154abd458 LLDB`llvm::LegacyJITSymbolResolver::lookup(this=<unavailable>, Symbols=<unavailable>, OnResolved=<unavailable>)>) at JITSymbol.cpp:125:22 [opt]
    frame apple#22: 0x0000000154abf6f3 LLDB`llvm::RuntimeDyldImpl::resolveExternalSymbols(this=0x000000013cfeea20) at RuntimeDyld.cpp:1195:16 [opt]
    frame apple#23: 0x0000000154abecde LLDB`llvm::RuntimeDyldImpl::resolveRelocations(this=0x000000013cfeea20) at RuntimeDyld.cpp:131:18 [opt]
    frame apple#24: 0x0000000154ab1482 LLDB`llvm::MCJIT::finalizeLoadedModules(this=0x0000000107e0ea00) at MCJIT.cpp:242:8 [opt]
    frame apple#25: 0x0000000154ab24ec LLDB`llvm::MCJIT::getGlobalValueAddress(this=0x0000000107e0ea00, Name=<unavailable>) at MCJIT.cpp:400:5 [opt]
    frame apple#26: 0x000000014fef499d LLDB`lldb_private::IRExecutionUnit::PopulateSymtab(this=0x00000001004db860, obj_file=<unavailable>, symtab=0x0000600003342f80) at IRExecutionUnit.cpp:1246:34 [opt]
    frame apple#27: 0x00000001503e4bf1 LLDB`ObjectFileJIT::ParseSymtab(this=0x0000600003d04f18, symtab=0x0000600003342f80) at ObjectFileJIT.cpp:112:18 [opt]
    frame apple#28: 0x000000014ff93a14 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) at ObjectFile.cpp:764:9 [opt]
    frame apple#29: 0x000000014ff93998 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) [inlined] decltype(__f=0x00007ff7bfefa180)::$_0>(fp)()) std::__1::__invoke<lldb_private::ObjectFile::GetSymtab()::$_0>(lldb_private::ObjectFile::GetSymtab()::$_0&&) at type_traits:3918:1 [opt]
    frame apple#30: 0x000000014ff93998 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) [inlined] void std::__1::__call_once_param<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >::__execute<>(this=<unavailable>, (null)=<unavailable>) at mutex:630:9 [opt]
    frame apple#31: 0x000000014ff93984 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(void*) [inlined] std::__1::__call_once_param<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >::operator(this=<unavailable>)() at mutex:622:9 [opt]
    frame apple#32: 0x000000014ff93984 LLDB`void std::__1::__call_once_proxy<std::__1::tuple<lldb_private::ObjectFile::GetSymtab()::$_0&&> >(__vp=<unavailable>) at mutex:658:5 [opt]
    frame apple#33: 0x00007ff80dba5242 libc++.1.dylib`std::__1::__call_once(unsigned long volatile&, void*, void (*)(void*)) + 139
    frame apple#34: 0x000000014ff9235d LLDB`lldb_private::ObjectFile::GetSymtab() at mutex:676:9 [opt]
    frame apple#35: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab() [inlined] void llvm::call_once<lldb_private::ObjectFile::GetSymtab()::$_0>(flag=<unavailable>, F=<unavailable>)::$_0&&) at Threading.h:89:5 [opt]
    frame apple#36: 0x000000014ff92334 LLDB`lldb_private::ObjectFile::GetSymtab(this=0x0000600003d04f18) at ObjectFile.cpp:758:5 [opt]
    frame apple#37: 0x0000000150531d67 LLDB`SymbolFileSymtab::CalculateAbilities(this=0x0000600003e20100) at SymbolFileSymtab.cpp:60:42 [opt]
    frame apple#38: 0x000000015053001d LLDB`lldb_private::SymbolFileCommon::GetAbilities(this=0x0000600003e20100) at SymbolFile.h:478:21 [opt]
    frame apple#39: 0x000000014ff9a8cd LLDB`lldb_private::SymbolFile::FindPlugin(objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolFile.cpp:71:62 [opt]
    frame apple#40: 0x000000014ff9f4bd LLDB`lldb_private::SymbolVendor::AddSymbolFileRepresentation(this=0x00006000002b0560, objfile_sp=std::__1::shared_ptr<lldb_private::ObjectFile>::element_type @ 0x0000600003d04f18 strong=7 weak=2) at SymbolVendor.cpp:71:27 [opt]
    frame apple#41: 0x000000014ff9f419 LLDB`lldb_private::SymbolVendor::FindPlugin(module_sp=std::__1::shared_ptr<lldb_private::Module>::element_type @ 0x0000000106589ca0 strong=12 weak=26, feedback_strm=0x0000000000000000) at SymbolVendor.cpp:57:16 [opt]
    frame apple#42: 0x000000014fe8d2a0 LLDB`lldb_private::Module::GetSymbolFile(this=0x0000000106589ca0, can_create=<unavailable>, feedback_strm=0x0000000000000000) at Module.cpp:1083:13 [opt]
    frame apple#43: 0x000000015041f366 LLDB`lldb_private::PlatformDarwin::LocateExecutableScriptingResources(this=<unavailable>, target=0x000000010309e800, module=0x0000000106589ca0, feedback_stream=0x00007ff7bfefa770) at PlatformDarwin.cpp:212:40 [opt]
    frame apple#44: 0x000000014fe8f97c LLDB`lldb_private::Module::LoadScriptingResourceInTarget(this=<unavailable>, target=0x000000010309e800, error=0x00007ff7bfefa750, feedback_stream=<unavailable>) at Module.cpp:1588:44 [opt]
    frame apple#45: 0x0000000150027520 LLDB`lldb_private::Target::ModulesDidLoad(lldb_private::ModuleList&) [inlined] LoadScriptingResourceForModule(module_sp=<unavailable>, target=0x000000010309e800) at Target.cpp:1415:32 [opt]
    frame apple#46: 0x00000001500274f4 LLDB`lldb_private::Target::ModulesDidLoad(this=0x000000010309e800, module_list=<unavailable>) at Target.cpp:1672:7 [opt]
    frame apple#47: 0x00000001500284ca LLDB`non-virtual thunk to lldb_private::Target::NotifyModuleAdded(lldb_private::ModuleList const&, std::__1::shared_ptr<lldb_private::Module> const&) at Target.cpp:1637:5 [opt]
    frame apple#48: 0x00000001500284a7 LLDB`non-virtual thunk to lldb_private::Target::NotifyModuleAdded(lldb_private::ModuleList const&, std::__1::shared_ptr<lldb_private::Module> const&) at Target.cpp:0 [opt]
    frame apple#49: 0x000000014fe91f8b LLDB`lldb_private::ModuleList::Append(std::__1::shared_ptr<lldb_private::Module> const&, bool) at ModuleList.cpp:334:19 [opt]
    frame apple#50: 0x000000014fe91f44 LLDB`lldb_private::ModuleList::Append(this=0x000000010309eb48, module_sp=std::__1::shared_ptr<lldb_private::Module>::element_type @ 0x0000000106589ca0 strong=12 weak=26, notify=<unavailable>) at ModuleList.cpp:339:3 [opt]
    frame apple#51: 0x000000014fef5200 LLDB`lldb_private::IRExecutionUnit::CreateJITModule(this=<unavailable>, name="$__lldb_expr2") at IRExecutionUnit.cpp:1339:27 [opt]
    frame apple#52: 0x000000015011063b LLDB`lldb_private::SwiftUserExpression::Parse(this=<unavailable>, diagnostic_manager=<unavailable>, exe_ctx=<unavailable>, execution_policy=eExecutionPolicyOnlyWhenNeeded, keep_result_in_memory=<unavailable>, generate_debug_info=<unavailable>) at SwiftUserExpression.cpp:802:28 [opt]
    frame apple#53: 0x000000014ff0cd05 LLDB`lldb_private::UserExpression::Evaluate(exe_ctx=<unavailable>, options=0x00006000033441e0, expr="", prefix="", result_valobj_sp=nullptr, error=0x00007ff7bfefaf40, fixed_expression=Summary Unavailable, ctx_obj=0x0000000000000000) at UserExpression.cpp:281:27 [opt]
    frame apple#54: 0x000000015002e124 LLDB`lldb_private::Target::EvaluateExpression(this=0x000000010309e800, expr="", exe_scope=<unavailable>, result_valobj_sp=nullptr, options=<unavailable>, fixed_expression=Summary Unavailable, ctx_obj=0x0000000000000000) at Target.cpp:2960:25 [opt]
    frame apple#55: 0x000000014fcc3e62 LLDB`lldb::SBFrame::EvaluateExpression(this=<unavailable>, expr=<unavailable>, options=0x0000600000011880) at SBFrame.cpp:1084:17 [opt]
    frame apple#56: 0x000000014fdaaf70 LLDB`_wrap_SBFrame_EvaluateExpression(_object*, _object*) at LLDBWrapPython.cpp:32887:22 [opt]
    frame apple#57: 0x000000014fdaaebf LLDB`_wrap_SBFrame_EvaluateExpression(self=<unavailable>, args=<unavailable>) at LLDBWrapPython.cpp:32933:18 [opt]

(cherry picked from commit ba81700)
adrian-prantl pushed a commit that referenced this pull request May 5, 2023
@Michael137
[lldb][TypeSystem] ForEach: Don't hold the TypeSystemMap lock across …
ac6d5b1 
…callback

The `TypeSystemMap::m_mutex` guards against concurrent modifications
of members of `TypeSystemMap`. In particular, `m_map`.

`TypeSystemMap::ForEach` iterates through the entire `m_map` calling
a user-specified callback for each entry. This is all done while
`m_mutex` is locked. However, there's nothing that guarantees that
the callback itself won't call back into `TypeSystemMap` APIs on the
same thread. This lead to double-locking `m_mutex`, which is undefined
behaviour. We've seen this cause a deadlock in the swift plugin with
following backtrace:

```

int main() {
    std::unique_ptr<int> up = std::make_unique<int>(5);

    volatile int val = *up;
    return val;
}

clang++ -std=c++2a -g -O1 main.cpp

./bin/lldb -o “br se -p return” -o run -o “v *up” -o “expr *up” -b
```

```
frame #4: std::lock_guard<std::mutex>::lock_guard
frame #5: lldb_private::TypeSystemMap::GetTypeSystemForLanguage <<<< Lock #2
frame #6: lldb_private::TypeSystemMap::GetTypeSystemForLanguage
frame #7: lldb_private::Target::GetScratchTypeSystemForLanguage
...
frame #26: lldb_private::SwiftASTContext::LoadLibraryUsingPaths
frame #27: lldb_private::SwiftASTContext::LoadModule
frame #30: swift::ModuleDecl::collectLinkLibraries
frame #31: lldb_private::SwiftASTContext::LoadModule
frame #34: lldb_private::SwiftASTContext::GetCompileUnitImportsImpl
frame #35: lldb_private::SwiftASTContext::PerformCompileUnitImports
frame #36: lldb_private::TypeSystemSwiftTypeRefForExpressions::GetSwiftASTContext
frame #37: lldb_private::TypeSystemSwiftTypeRefForExpressions::GetPersistentExpressionState
frame #38: lldb_private::Target::GetPersistentSymbol
frame #41: lldb_private::TypeSystemMap::ForEach                 <<<< Lock #1
frame #42: lldb_private::Target::GetPersistentSymbol
frame #43: lldb_private::IRExecutionUnit::FindInUserDefinedSymbols
frame #44: lldb_private::IRExecutionUnit::FindSymbol
frame #45: lldb_private::IRExecutionUnit::MemoryManager::GetSymbolAddressAndPresence
frame #46: lldb_private::IRExecutionUnit::MemoryManager::findSymbol
frame #47: non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol
frame #48: llvm::LinkingSymbolResolver::findSymbol
frame #49: llvm::LegacyJITSymbolResolver::lookup
frame #50: llvm::RuntimeDyldImpl::resolveExternalSymbols
frame #51: llvm::RuntimeDyldImpl::resolveRelocations
frame #52: llvm::MCJIT::finalizeLoadedModules
frame #53: llvm::MCJIT::finalizeObject
frame #54: lldb_private::IRExecutionUnit::ReportAllocations
frame #55: lldb_private::IRExecutionUnit::GetRunnableInfo
frame #56: lldb_private::ClangExpressionParser::PrepareForExecution
frame #57: lldb_private::ClangUserExpression::TryParse
frame #58: lldb_private::ClangUserExpression::Parse
```

Our solution is to simply iterate over a local copy of `m_map`.

**Testing**

* Confirmed on manual reproducer (would reproduce 100% of the time
  before the patch)

Differential Revision: https://reviews.llvm.org/D149949

(cherry picked from commit dda3a6a)
swift-ci pushed a commit that referenced this pull request May 5, 2023
@Michael137
[lldb][TypeSystem] ForEach: Don't hold the TypeSystemMap lock across …
e74f03d 
…callback

The `TypeSystemMap::m_mutex` guards against concurrent modifications
of members of `TypeSystemMap`. In particular, `m_map`.

`TypeSystemMap::ForEach` iterates through the entire `m_map` calling
a user-specified callback for each entry. This is all done while
`m_mutex` is locked. However, there's nothing that guarantees that
the callback itself won't call back into `TypeSystemMap` APIs on the
same thread. This lead to double-locking `m_mutex`, which is undefined
behaviour. We've seen this cause a deadlock in the swift plugin with
following backtrace:

```

int main() {
    std::unique_ptr<int> up = std::make_unique<int>(5);

    volatile int val = *up;
    return val;
}

clang++ -std=c++2a -g -O1 main.cpp

./bin/lldb -o “br se -p return” -o run -o “v *up” -o “expr *up” -b
```

```
frame #4: std::lock_guard<std::mutex>::lock_guard
frame #5: lldb_private::TypeSystemMap::GetTypeSystemForLanguage <<<< Lock #2
frame #6: lldb_private::TypeSystemMap::GetTypeSystemForLanguage
frame #7: lldb_private::Target::GetScratchTypeSystemForLanguage
...
frame #26: lldb_private::SwiftASTContext::LoadLibraryUsingPaths
frame #27: lldb_private::SwiftASTContext::LoadModule
frame #30: swift::ModuleDecl::collectLinkLibraries
frame #31: lldb_private::SwiftASTContext::LoadModule
frame #34: lldb_private::SwiftASTContext::GetCompileUnitImportsImpl
frame #35: lldb_private::SwiftASTContext::PerformCompileUnitImports
frame #36: lldb_private::TypeSystemSwiftTypeRefForExpressions::GetSwiftASTContext
frame #37: lldb_private::TypeSystemSwiftTypeRefForExpressions::GetPersistentExpressionState
frame #38: lldb_private::Target::GetPersistentSymbol
frame #41: lldb_private::TypeSystemMap::ForEach                 <<<< Lock #1
frame #42: lldb_private::Target::GetPersistentSymbol
frame #43: lldb_private::IRExecutionUnit::FindInUserDefinedSymbols
frame #44: lldb_private::IRExecutionUnit::FindSymbol
frame #45: lldb_private::IRExecutionUnit::MemoryManager::GetSymbolAddressAndPresence
frame #46: lldb_private::IRExecutionUnit::MemoryManager::findSymbol
frame #47: non-virtual thunk to lldb_private::IRExecutionUnit::MemoryManager::findSymbol
frame #48: llvm::LinkingSymbolResolver::findSymbol
frame #49: llvm::LegacyJITSymbolResolver::lookup
frame #50: llvm::RuntimeDyldImpl::resolveExternalSymbols
frame #51: llvm::RuntimeDyldImpl::resolveRelocations
frame #52: llvm::MCJIT::finalizeLoadedModules
frame #53: llvm::MCJIT::finalizeObject
frame #54: lldb_private::IRExecutionUnit::ReportAllocations
frame #55: lldb_private::IRExecutionUnit::GetRunnableInfo
frame #56: lldb_private::ClangExpressionParser::PrepareForExecution
frame #57: lldb_private::ClangUserExpression::TryParse
frame #58: lldb_private::ClangUserExpression::Parse
```

Our solution is to simply iterate over a local copy of `m_map`.

**Testing**

* Confirmed on manual reproducer (would reproduce 100% of the time
  before the patch)

Differential Revision: https://reviews.llvm.org/D149949
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@JDevlieghere JDevlieghere JDevlieghere approved these changes

@dcci dcci dcci approved these changes

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@adrian-prantl @JDevlieghere @dcci