Extended Description

Hitting this assert in a Chromium build on Linux with tip-of-tree Clang:

[1/1] CXX obj/base/allocator/tcmalloc/thread_cache.o
FAILED: obj/base/allocator/tcmalloc/thread_cache.o
../../../../../../../../work/llvm/build.release/bin/clang++ -MMD -MF obj/base/allocator/tcmalloc/thread_cache.o.d -DNO_HEAP_CHECK -DV8_DEPRECATION_WARNINGS -DUSE_UDEV -DUSE_AURA=1 -DUSE_PANGO=1 -DUSE_CAIRO=1 -DUSE_GLIB=1 -DUSE_NSS_CERTS=1 -DUSE_X11=1 -DFULL_SAFE_BROWSING
-DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DCHROMIUM_BUILD -DFIELDTRIAL_TESTING_ENABLED -DCR_CLANG_REVISION="298540" -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DCOMPONENT_BUILD -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DTCMALLOC_D
ONT_REPLACE_SYSTEM_ALLOC -I../../base/allocator -I../../third_party/tcmalloc/chromium/src/base -I../../third_party/tcmalloc/chromium/src -I../.. -Igen -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D
TIMESTAMP= -funwind-tables -fPIC -pipe -B../../third_party/binutils/Linux_x64/Release/bin -fcolor-diagnostics -m64 -march=x86-64 -pthread -fomit-frame-pointer -g2 --sysroot=../../build/linux/debian_jessie_amd64-sysroot -fvisibility=hidden -Wheader-hygiene -Wstring-co
nversion -Wtautological-overlap-compare -Werror -Wall -Wno-unused-variable -Wno-missing-field-initializers -Wno-unused-parameter -Wno-c++11-narrowing -Wno-covered-switch-default -Wno-unneeded-internal-declaration -Wno-inconsistent-missing-override -Wno-undefined-var-temp
late -Wno-nonportable-include-path -Wno-address-of-packed-member -Wno-unused-lambda-capture -Wno-user-defined-warnings -Wno-reorder -Wno-unused-function -Wno-unused-local-typedefs -Wno-unused-private-field -Wno-sign-compare -Wno-unused-result -O2 -fno-ident -fdata-sectio
ns -ffunction-sections -fvisibility-inlines-hidden -std=gnu++11 -fno-rtti -fno-exceptions -Wno-deprecated -c ../../third_party/tcmalloc/chromium/src/thread_cache.cc -o obj/base/allocator/tcmalloc/thread_cache.o
clang-4.0: ../lib/CodeGen/AsmPrinter/DwarfDebug.h:131: void llvm::DbgVariable::addMMIEntry(const llvm::DbgVariable&): Assertion `V.Var == Var && "conflicting variable"' failed.
#​0 0x0000000001f4322a llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1f4322a)
#​1 0x0000000001f4123e llvm::sys::RunSignalHandlers() (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1f4123e)
#​2 0x0000000001f413a2 SignalHandler(int) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1f413a2)
#​3 0x00007f686f8c8330 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x10330)
#​4 0x00007f686e6b9c37 gsignal /build/eglibc-MjiXCM/eglibc-2.19/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0
#​5 0x00007f686e6bd028 abort /build/eglibc-MjiXCM/eglibc-2.19/stdlib/abort.c:91:0
#​6 0x00007f686e6b2bf6 __assert_fail_base /build/eglibc-MjiXCM/eglibc-2.19/assert/assert.c:92:0
#​7 0x00007f686e6b2ca2 (/lib/x86_64-linux-gnu/libc.so.6+0x2fca2)
#​8 0x00000000024fd43a llvm::DwarfFile::addScopeVariable(llvm::LexicalScope*, llvm::DbgVariable*) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x24fd43a)
#​9 0x00000000024f3852 llvm::DwarfDebug::createAbstractVariable(llvm::DILocalVariable const*, llvm::LexicalScope*) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x24f3852)
#​10 0x00000000024f3a93 llvm::DwarfDebug::ensureAbstractVariableIsCreated(std::pair<llvm::DILocalVariable const*, llvm::DILocation const*>, llvm::MDNode const*) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x24f3a93)
#​11 0x00000000024f51e5 llvm::DwarfDebug::endFunctionImpl(llvm::MachineFunction const*) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x24f51e5)
#​12 0x0000000002528448 llvm::DebugHandlerBase::endFunction(llvm::MachineFunction const*) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x2528448)
#​13 0x00000000024d6159 llvm::AsmPrinter::EmitFunctionBody() (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x24d6159)
#​14 0x0000000001407d40 llvm::X86AsmPrinter::runOnMachineFunction(llvm::MachineFunction&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1407d40)
#​15 0x0000000001846da5 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1846da5)
#​16 0x0000000001b19c33 llvm::FPPassManager::runOnFunction(llvm::Function&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1b19c33)
#​17 0x0000000001b19cdc llvm::FPPassManager::runOnModule(llvm::Module&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1b19cdc)
#​18 0x0000000001b1aa3f llvm::legacy::PassManagerImpl::run(llvm::Module&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x1b1aa3f)
#​19 0x00000000020c67fe (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_deletellvm::raw_pwrite_stream >) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x20c67fe)
#​20 0x00000000020c7b59 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*, clang::BackendAction, std::unique_p
tr<llvm::raw_pwrite_stream, std::default_deletellvm::raw_pwrite_stream >) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x20c7b59)
#​21 0x0000000002740b6b clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x2740b6b)
#​22 0x0000000002b2ace2 clang::ParseAST(clang::Sema&, bool, bool) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x2b2ace2)
#​23 0x000000000274023f clang::CodeGenAction::ExecuteAction() (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x274023f)
#​24 0x000000000243ec76 clang::FrontendAction::Execute() (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x243ec76)
#​25 0x0000000002418b16 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x2418b16)
#​26 0x00000000024c92f4 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/local/google/work/llvm/build.release/bin/clang-4.0+0x24c92f4)