Author: jankratochvil Date: Mon Apr 30 14:37:30 2018 New Revision: 331229 URL: http://llvm.org/viewvc/llvm-project?rev=331229&view=rev Log: Protect DWARFCompileUnit::m_die_array by a new mutex
Multiple DW_TAG_compile_unit being indexed in a multithreaded way can request reading of the same DW_TAG_partial_unit. Unfortunately one cannot detect DWZ file ahead of time to disable such locking overhead as DWARFCompileUnit::Extract does not read the first DIE which is the only place one could find early enough if the DWARF file is using any DW_TAG_partial_unit. Differential revision: https://reviews.llvm.org/D40470 Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.h Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp?rev=331229&r1=331228&r2=331229&view=diff ============================================================================== --- lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp (original) +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp Mon Apr 30 14:37:30 2018 @@ -41,9 +41,20 @@ DWARFUnit::~DWARFUnit() {} // Parses a compile unit and indexes its DIEs if it hasn't already been done. //---------------------------------------------------------------------- size_t DWARFUnit::ExtractDIEsIfNeeded(bool cu_die_only) { - const size_t initial_die_array_size = m_die_array.size(); - if ((cu_die_only && initial_die_array_size > 0) || initial_die_array_size > 1) - return 0; // Already parsed + size_t initial_die_array_size; + auto already_parsed = [cu_die_only, &initial_die_array_size, this]() -> bool { + initial_die_array_size = m_die_array.size(); + return (cu_die_only && initial_die_array_size > 0) + || initial_die_array_size > 1; + }; + { + llvm::sys::ScopedReader lock(m_extractdies_mutex); + if (already_parsed()) + return 0; + } + llvm::sys::ScopedWriter lock(m_extractdies_mutex); + if (already_parsed()) + return 0; static Timer::Category func_cat(LLVM_PRETTY_FUNCTION); Timer scoped_timer( @@ -304,6 +315,8 @@ void DWARFUnit::SetAddrBase(dw_addr_t ad void DWARFUnit::ClearDIEs(bool keep_compile_unit_die) { if (m_die_array.size() > 1) { + llvm::sys::ScopedWriter lock(m_extractdies_mutex); + // std::vectors never get any smaller when resized to a smaller size, or // when clear() or erase() are called, the size will report that it is // smaller, but the memory allocated remains intact (call capacity() to see Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.h URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.h?rev=331229&r1=331228&r2=331229&view=diff ============================================================================== --- lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.h (original) +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.h Mon Apr 30 14:37:30 2018 @@ -13,6 +13,7 @@ #include "DWARFDIE.h" #include "DWARFDebugInfoEntry.h" #include "lldb/lldb-enumerations.h" +#include "llvm/Support/RWMutex.h" class DWARFUnit; class DWARFCompileUnit; @@ -160,6 +161,7 @@ protected: // If this is a dwo compile unit this is the offset of the base compile unit // in the main object file dw_offset_t m_base_obj_offset = DW_INVALID_OFFSET; + llvm::sys::RWMutex m_extractdies_mutex; static void IndexPrivate(DWARFUnit *dwarf_cu, const lldb::LanguageType cu_language, _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
