TSAN: data race on library map

[rmacnak-google]

WARNING: ThreadSanitizer: data race (pid=495479)
  Write of size 8 at 0x727000002ba8 by main thread:
    #0 dart::ObjectStore::set_libraries_map(dart::Array const&) out/ReleaseTSANX64/../../runtime/vm/object_store.h:512:3 (dart+0x27a30a1)
    #1 dart::Library::Register(dart::Thread*) const out/ReleaseTSANX64/../../runtime/vm/object.cc:15090:17 (dart+0x27a30a1)
    #2 dart::kernel::KernelLoader::LookupLibrary(dart::kernel::NameIndex) out/ReleaseTSANX64/../../runtime/vm/kernel_loader.cc:2185:12 (dart+0x274ee0c)
    #3 dart::kernel::KernelLoader::LoadLibrary(long) out/ReleaseTSANX64/../../runtime/vm/kernel_loader.cc:827:26 (dart+0x27526e5)
    #4 dart::kernel::KernelLoader::LoadProgram(bool) out/ReleaseTSANX64/../../runtime/vm/kernel_loader.cc:533:7 (dart+0x2750faa)
    #5 dart::kernel::KernelLoader::LoadEntireProgram(dart::kernel::Program*, bool) out/ReleaseTSANX64/../../runtime/vm/kernel_loader.cc:263:34 (dart+0x27502b6)
    #6 Dart_LoadScriptFromKernel out/ReleaseTSANX64/../../runtime/vm/dart_api_impl.cc:5420:23 (dart+0x2cbbc1d)
    #7 dart::bin::IsolateSetupHelper(_Dart_Isolate*, bool, char const*, char const*, bool, Dart_IsolateFlags*, char**, int*) out/ReleaseTSANX64/../../runtime/bin/main_impl.cc:330:14 (dart+0x23799e7)
    #8 dart::bin::CreateIsolateGroupAndSetupHelper(bool, char const*, char const*, char const*, Dart_IsolateFlags*, void*, char**, int*) out/ReleaseTSANX64/../../runtime/bin/main_impl.cc:826:23 (dart+0x2377573)
    #9 dart::bin::RunMainIsolate(char const*, char const*, dart::bin::CommandLineOptions*) out/ReleaseTSANX64/../../runtime/bin/main_impl.cc:1025:26 (dart+0x2376df3)
    #10 dart::bin::main(int, char**) out/ReleaseTSANX64/../../runtime/bin/main_impl.cc:1442:7 (dart+0x2378303)
    #11 main out/ReleaseTSANX64/../../runtime/bin/main.cc:9:3 (dart+0x2376cb4)

  Previous read of size 8 at 0x727000002ba8 by thread T4:
    #0 dart::ObjectStore::libraries_map() const out/ReleaseTSANX64/../../runtime/vm/object_store.h:512:3 (dart+0x27a222c)
    #1 dart::Library::LookupLibrary(dart::Thread*, dart::String const&) out/ReleaseTSANX64/../../runtime/vm/object.cc:14943:21 (dart+0x27a222c)
    #2 dart::MethodRecognizer::ResultCidFromPragma(dart::Object const&) out/ReleaseTSANX64/../../runtime/vm/compiler/method_recognizer.cc:55:47 (dart+0x2bfeaaf)
    #3 dart::StaticCallInstr::ComputeType() const out/ReleaseTSANX64/../../runtime/vm/compiler/backend/type_propagator.cc:1581:26 (dart+0x2b3aea1)
    #4 dart::Definition::Type() out/ReleaseTSANX64/../../runtime/vm/compiler/backend/il.h:2521:35 (dart+0x2a3448c)
    #5 dart::Definition::ReplaceUsesWith(dart::Definition*) out/ReleaseTSANX64/../../runtime/vm/compiler/backend/il.cc:1509:42 (dart+0x2a3448c)
    #6 dart::Definition::ReplaceWithResult(dart::Instruction*, dart::Definition*, dart::ForwardInstructionIterator*) out/ReleaseTSANX64/../../runtime/vm/compiler/backend/il.cc:1650:3 (dart+0x2a35d85)
    #7 dart::Definition::ReplaceWith(dart::Definition*, dart::ForwardInstructionIterator*) out/ReleaseTSANX64/../../runtime/vm/compiler/backend/il.cc:1674:3 (dart+0x2a35efc)
    #8 dart::JitCallSpecializer::ReplaceWithStaticCall(dart::InstanceCallInstr*, dart::Function const&, long) out/ReleaseTSANX64/../../runtime/vm/compiler/jit/jit_call_specializer.cc:60:10 (dart+0x2bfd540)
    #9 dart::JitCallSpecializer::VisitInstanceCall(dart::InstanceCallInstr*) out/ReleaseTSANX64/../../runtime/vm/compiler/jit/jit_call_specializer.cc (dart+0x2bfd86f)
    #10 dart::InstanceCallInstr::Accept(dart::InstructionVisitor*) out/ReleaseTSANX64/../../runtime/vm/compiler/backend/il.cc:1273:1 (dart+0x2a3159c)
    #11 dart::FlowGraphVisitor::VisitBlocks() out/ReleaseTSANX64/../../runtime/vm/compiler/backend/il.cc:1389:21 (dart+0x2a33de4)
    #12 dart::CallSpecializer::ApplyICData() out/ReleaseTSANX64/../../runtime/vm/compiler/call_specializer.cc:53:3 (dart+0x2b3e765)
    #13 dart::CompilerPass_ApplyICData::DoBody(dart::CompilerPassState*) const out/ReleaseTSANX64/../../runtime/vm/compiler/compiler_pass.cc:389:1 (dart+0x2b5c8f9)
    #14 dart::CompilerPass::Run(dart::CompilerPassState*) const out/ReleaseTSANX64/../../runtime/vm/compiler/compiler_pass.cc:230:18 (dart+0x2b5bdd2)
    #15 dart::CompilerPass::RunPipeline(dart::CompilerPass::PipelineMode, dart::CompilerPassState*, bool) out/ReleaseTSANX64/../../runtime/vm/compiler/compiler_pass.cc:310:3 (dart+0x2b5c2ea)
    #16 dart::CompileParsedFunctionHelper::Compile(dart::CompilationPipeline*) out/ReleaseTSANX64/../../runtime/vm/compiler/jit/compiler.cc:574:22 (dart+0x291ea78)
    #17 dart::CompileFunctionHelper(dart::CompilationPipeline*, dart::Function const&, bool, long) out/ReleaseTSANX64/../../runtime/vm/compiler/jit/compiler.cc:719:46 (dart+0x291f7d3)
    #18 dart::Compiler::CompileOptimizedFunction(dart::Thread*, dart::Function const&, long) out/ReleaseTSANX64/../../runtime/vm/compiler/jit/compiler.cc:904:10 (dart+0x29202ff)
    #19 dart::BackgroundCompiler::Run() out/ReleaseTSANX64/../../runtime/vm/compiler/jit/compiler.cc:1144:7 (dart+0x2920e4e)
    #20 dart::BackgroundCompilerTask::Run() out/ReleaseTSANX64/../../runtime/vm/compiler/jit/compiler.cc:1104:46 (dart+0x2921da3)
    #21 dart::ThreadPool::WorkerLoop(dart::ThreadPool::Worker*) out/ReleaseTSANX64/../../runtime/vm/thread_pool.cc:203:15 (dart+0x29043be)
    #22 dart::ThreadPool::Worker::Main(unsigned long) out/ReleaseTSANX64/../../runtime/vm/thread_pool.cc:363:9 (dart+0x290491a)
    #23 dart::ThreadStart(void*) out/ReleaseTSANX64/../../runtime/vm/os_thread_linux.cc:97:5 (dart+0x28757e6)

log

The library map should probably be guarded by the program lock.