Author: Raphael Isemann Date: 2020-05-11T16:02:51+02:00 New Revision: f8af9f5fca7dac5479a43837daa3e2bd897b00b7
URL: https://github.com/llvm/llvm-project/commit/f8af9f5fca7dac5479a43837daa3e2bd897b00b7 DIFF: https://github.com/llvm/llvm-project/commit/f8af9f5fca7dac5479a43837daa3e2bd897b00b7.diff LOG: [lldb] Add missing nullptr checks to AppleObjCRuntime::GetBacktraceThreadFromException Summary: We got a few crash reports where LLDB crashes while derefencing the `frames_value` shared_ptr in the AppleObjCRuntime::GetBacktraceThreadFromException. `GetChildMemberWithName` returns a nullptr when an error occurs, so this seems to be just a missing nullptr check. This patch adds that nullptr check and the other ones in the similar code directly below. Fixes rdar://62174039 Reviewers: jingham, kubamracek Reviewed By: jingham Subscribers: abidh, JDevlieghere Differential Revision: https://reviews.llvm.org/D78798 Added: Modified: lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp index 0fe0d9217e6a..e00ce9d019df 100644 --- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp +++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp @@ -501,19 +501,32 @@ ValueObjectSP AppleObjCRuntime::GetExceptionObjectForThread( return ValueObjectSP(); } +/// Utility method for error handling in GetBacktraceThreadFromException. +/// \param msg The message to add to the log. +/// \return An invalid ThreadSP to be returned from +/// GetBacktraceThreadFromException. +LLVM_NODISCARD +static ThreadSP FailExceptionParsing(llvm::StringRef msg) { + Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_LANGUAGE)); + LLDB_LOG(log, "Failed getting backtrace from exception: {0}", msg); + return ThreadSP(); +} + ThreadSP AppleObjCRuntime::GetBacktraceThreadFromException( lldb::ValueObjectSP exception_sp) { ValueObjectSP reserved_dict = exception_sp->GetChildMemberWithName(ConstString("reserved"), true); - if (!reserved_dict) return ThreadSP(); + if (!reserved_dict) + return FailExceptionParsing("Failed to get 'reserved' member."); reserved_dict = reserved_dict->GetSyntheticValue(); - if (!reserved_dict) return ThreadSP(); + if (!reserved_dict) + return FailExceptionParsing("Failed to get synthetic value."); TypeSystemClang *clang_ast_context = TypeSystemClang::GetScratch(*exception_sp->GetTargetSP()); if (!clang_ast_context) - return ThreadSP(); + return FailExceptionParsing("Failed to get scratch AST."); CompilerType objc_id = clang_ast_context->GetBasicType(lldb::eBasicTypeObjCID); ValueObjectSP return_addresses; @@ -554,15 +567,22 @@ ThreadSP AppleObjCRuntime::GetBacktraceThreadFromException( } } - if (!return_addresses) return ThreadSP(); + if (!return_addresses) + return FailExceptionParsing("Failed to get return addresses."); auto frames_value = return_addresses->GetChildMemberWithName(ConstString("_frames"), true); + if (!frames_value) + return FailExceptionParsing("Failed to get frames_value."); addr_t frames_addr = frames_value->GetValueAsUnsigned(0); auto count_value = return_addresses->GetChildMemberWithName(ConstString("_cnt"), true); + if (!count_value) + return FailExceptionParsing("Failed to get count_value."); size_t count = count_value->GetValueAsUnsigned(0); auto ignore_value = return_addresses->GetChildMemberWithName(ConstString("_ignore"), true); + if (!ignore_value) + return FailExceptionParsing("Failed to get ignore_value."); size_t ignore = ignore_value->GetValueAsUnsigned(0); size_t ptr_size = m_process->GetAddressByteSize(); @@ -574,7 +594,8 @@ ThreadSP AppleObjCRuntime::GetBacktraceThreadFromException( pcs.push_back(pc); } - if (pcs.empty()) return ThreadSP(); + if (pcs.empty()) + return FailExceptionParsing("Failed to get PC list."); ThreadSP new_thread_sp(new HistoryThread(*m_process, 0, pcs)); m_process->GetExtendedThreadList().AddThread(new_thread_sp); _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
