First bad build: https://ci.chromium.org/buildbot/chromium.clang/CrWinClangLLD/240

Last good build:
https://ci.chromium.org/buildbot/chromium.clang/CrWinClangLLD64/231

Note: Builds in between are failing because of a different problem, which has since been fixed. The locally defined symbol imported error may have started on any of the builds in between.

Logs: https://logs.chromium.org/v/?s=chromium%2Fbb%2Fchromium.clang%2FCrWinClangLLD64%2F240%2F%2B%2Frecipes%2Fsteps%2Fcompile%2F0%2Fstdout

Excerpt:
[44240/48574] LINK cctest.exe cctest.exe.pdb
FAILED: cctest.exe cctest.exe.pdb 
C:/b/depot_tools/win_tools-2_7_6_bin/python/bin/python.exe ../../build/toolchain/win/tool_wrapper.py link-wrapper environment.x64 False ../../third_party/llvm-build/Release+Asserts/bin/lld-link.exe /nologo /OUT:./cctest.exe /PDB:./cctest.exe.pdb @./cctest.exe.rsp
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?SyncDecodeWasmModule@wasm@internal@v8@@YA?AV?$Result@V?$unique_ptr@UWasmModule@wasm@internal@v8@@U?$default_delete@UWasmModule@wasm@internal@v8@@@std@@@std@@@123@PEAVIsolate@23@PEBE1_NW4ModuleOrigin@123@@Z (defined in obj/v8/v8_base/module-decoder.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??0ResultBase@wasm@internal@v8@@QEAA@$$QEAV0123@@Z (defined in obj/v8/test/cctest/cctest_sources/test-run-wasm-machops.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??1ResultBase@wasm@internal@v8@@QEAA@XZ (defined in obj/v8/test/cctest/cctest_sources/test-run-wasm-machops.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?ok@ResultBase@wasm@internal@v8@@QEBA_NXZ (defined in obj/v8/test/cctest/cctest_sources/test-run-wasm-machops.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?CompileError@ErrorThrower@wasm@internal@v8@@QEAAXPEBDZZ (defined in obj/v8/v8_base/wasm-result.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?function_index@WasmExportedFunction@internal@v8@@QEAAHXZ (defined in obj/v8/v8_base/wasm-objects.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?module@WasmInstanceObject@internal@v8@@QEAAPEAUWasmModule@wasm@23@XZ (defined in obj/v8/v8_base/wasm-objects.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??0Zone@internal@v8@@QEAA@PEAVAccountingAllocator@12@PEBDW4SegmentSize@12@@Z (defined in obj/v8/v8_base/zone.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?SetupForTesting@WasmDebugInfo@internal@v8@@SAPEAVWasmInterpreter@wasm@23@V?$Handle@VWasmInstanceObject@internal@v8@@@23@@Z (defined in obj/v8/v8_base/wasm-debug.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??0HeapObjectsScope@WasmInterpreter@wasm@internal@v8@@QEAA@PEAV1234@V?$Handle@VWasmInstanceObject@internal@v8@@@34@@Z (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?GetThread@WasmInterpreter@wasm@internal@v8@@QEAAPEAVThread@1234@H@Z (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?Reset@Thread@WasmInterpreter@wasm@internal@v8@@QEAAXXZ (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?StartActivation@Thread@WasmInterpreter@wasm@internal@v8@@QEAAIXZ (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?InitFrame@Thread@WasmInterpreter@wasm@internal@v8@@QEAAXPEBUWasmFunction@345@PEAVWasmValue@345@@Z (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?Run@Thread@WasmInterpreter@wasm@internal@v8@@QEAA?AW4State@2345@H@Z (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??1HeapObjectsScope@WasmInterpreter@wasm@internal@v8@@QEAA@XZ (defined in obj/v8/v8_base/wasm-interpreter.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??1Zone@internal@v8@@QEAA@XZ (defined in obj/v8/v8_base/zone.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?InternalizeUtf8String@Factory@internal@v8@@QEAA?AV?$Handle@VString@internal@v8@@@23@PEBD@Z (defined in obj/v8/test/cctest/cctest_sources/cctest.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ??0LookupIterator@internal@v8@@QEAA@V?$Handle@VObject@internal@v8@@@12@V?$Handle@VName@internal@v8@@@12@V?$Handle@VJSReceiver@internal@v8@@@12@W4Configuration@012@@Z (defined in obj/v8/test/cctest/cctest_sources/cctest.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: obj/v8/wasm_module_runner/wasm-module-runner.obj: locally defined symbol imported: ?factory@LookupIterator@internal@v8@@QEBAPEAVFactory@23@XZ (defined in obj/v8/test/cctest/cctest_sources/cctest.obj)
..\..\third_party\llvm-build\Release+Asserts\bin\lld-link.exe: error: too many errors emitted, stopping now (use /ERRORLIMIT:0 to see all errors)