[clang] [clang] fix use after free in clang/tools/c-index-test/c-index-test.c (PR #127063)

Tue Feb 18 23:27:41 PST 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-lld-multistage-test` running on `ppc64le-lld-multistage-test` while building `clang` at step 12 "build-stage2-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/8866

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 12 (build-stage2-unified-tree) failure: build (failure)
...
461.394 [151/650/5664] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/module.c.o
461.395 [151/649/5665] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/metadata.c.o
461.399 [151/648/5666] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/object.c.o
461.400 [151/647/5667] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/targets.c.o
461.400 [151/646/5668] Building CXX object tools/llvm-isel-fuzzer/CMakeFiles/llvm-isel-fuzzer.dir/DummyISelFuzzer.cpp.o
461.401 [151/645/5669] Building CXX object tools/llvm-opt-fuzzer/CMakeFiles/llvm-opt-fuzzer.dir/DummyOptFuzzer.cpp.o
461.426 [151/644/5670] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/calc.c.o
461.596 [151/643/5671] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/debuginfo.c.o
461.616 [151/642/5672] Building C object tools/llvm-c-test/CMakeFiles/llvm-c-test.dir/disassemble.c.o
461.857 [151/641/5673] Building C object tools/clang/tools/c-index-test/CMakeFiles/c-index-test.dir/c-index-test.c.o
FAILED: tools/clang/tools/c-index-test/CMakeFiles/c-index-test.dir/c-index-test.c.o 
ccache /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/install/stage1/bin/clang -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage2/tools/clang/tools/c-index-test -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/tools/c-index-test -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage2/tools/clang/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage2/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include -fPIC -fno-semantic-interposition -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -UNDEBUG -std=gnu89 -MD -MT tools/clang/tools/c-index-test/CMakeFiles/c-index-test.dir/c-index-test.c.o -MF tools/clang/tools/c-index-test/CMakeFiles/c-index-test.dir/c-index-test.c.o.d -o tools/clang/tools/c-index-test/CMakeFiles/c-index-test.dir/c-index-test.c.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/tools/c-index-test/c-index-test.c
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/tools/c-index-test/c-index-test.c:1240:15: error: mixing declarations and code is a C99 extension [-Werror,-Wdeclaration-after-statement]
 1240 |   const char *b = basename(clang_getCString(source));
      |               ^
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/tools/c-index-test/c-index-test.c:1367:14: error: mixing declarations and code is a C99 extension [-Werror,-Wdeclaration-after-statement]
 1367 |     CXString source = GetCursorSource(Cursor);
      |              ^
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/clang/tools/c-index-test/c-index-test.c:1468:14: error: mixing declarations and code is a C99 extension [-Werror,-Wdeclaration-after-statement]
 1468 |     CXString CursorSource = GetCursorSource(C);
      |              ^
3 errors generated.
462.764 [151/640/5674] Building CXX object lib/Target/AMDGPU/TargetInfo/CMakeFiles/LLVMAMDGPUInfo.dir/AMDGPUTargetInfo.cpp.o
462.977 [151/639/5675] Building CXX object tools/llvm-cxxdump/CMakeFiles/llvm-cxxdump.dir/Error.cpp.o
463.397 [151/638/5676] Building CXX object lib/Target/AMDGPU/MCTargetDesc/CMakeFiles/LLVMAMDGPUDesc.dir/R600InstPrinter.cpp.o
464.723 [151/637/5677] Building CXX object tools/dsymutil/CMakeFiles/dsymutil.dir/CFBundle.cpp.o
465.021 [151/636/5678] Building CXX object tools/opt/CMakeFiles/opt.dir/opt.cpp.o
465.054 [151/635/5679] Building CXX object tools/llvm-ar/CMakeFiles/llvm-ar.dir/llvm-ar-driver.cpp.o
465.117 [151/634/5680] Building CXX object lib/Target/AMDGPU/MCTargetDesc/CMakeFiles/LLVMAMDGPUDesc.dir/R600MCTargetDesc.cpp.o
465.399 [151/633/5681] Building CXX object tools/clang/unittests/StaticAnalyzer/CMakeFiles/StaticAnalysisTests.dir/RangeSetTest.cpp.o
465.548 [151/632/5682] Building CXX object tools/lld/tools/lld/CMakeFiles/lld.dir/lld-driver.cpp.o
465.598 [151/631/5683] Building CXX object tools/clang/tools/driver/CMakeFiles/clang.dir/clang-driver.cpp.o
465.602 [151/630/5684] Building CXX object lib/Target/AMDGPU/Utils/CMakeFiles/LLVMAMDGPUUtils.dir/AMDGPUDelayedMCExpr.cpp.o
465.604 [151/629/5685] Building CXX object tools/llvm-lipo/CMakeFiles/llvm-lipo.dir/llvm-lipo-driver.cpp.o
465.623 [151/628/5686] Building CXX object tools/clang/tools/clang-scan-deps/CMakeFiles/clang-scan-deps.dir/clang-scan-deps-driver.cpp.o
465.784 [151/627/5687] Building CXX object tools/llvm-objdump/CMakeFiles/llvm-objdump.dir/llvm-objdump-driver.cpp.o
465.791 [151/626/5688] Building CXX object tools/llvm-nm/CMakeFiles/llvm-nm.dir/llvm-nm-driver.cpp.o
465.795 [151/625/5689] Building CXX object tools/llvm-libtool-darwin/CMakeFiles/llvm-libtool-darwin.dir/llvm-libtool-darwin-driver.cpp.o
465.901 [151/624/5690] Building CXX object tools/llvm-dwp/CMakeFiles/llvm-dwp.dir/llvm-dwp-driver.cpp.o
465.951 [151/623/5691] Building CXX object tools/llvm-ml/CMakeFiles/llvm-ml.dir/llvm-ml-driver.cpp.o
465.965 [151/622/5692] Building CXX object tools/sancov/CMakeFiles/sancov.dir/sancov-driver.cpp.o
466.088 [151/621/5693] Building CXX object tools/dsymutil/CMakeFiles/dsymutil.dir/dsymutil-driver.cpp.o
466.214 [151/620/5694] Building CXX object tools/llvm-gsymutil/CMakeFiles/llvm-gsymutil.dir/llvm-gsymutil-driver.cpp.o
466.498 [151/619/5695] Building CXX object tools/lld/MachO/CMakeFiles/lldMachO.dir/Target.cpp.o
468.078 [151/618/5696] Building CXX object unittests/DebugInfo/LogicalView/CMakeFiles/DebugInfoLogicalViewTests.dir/__/DWARF/DwarfUtils.cpp.o
468.510 [151/617/5697] Building CXX object unittests/DebugInfo/DWARF/CMakeFiles/DebugInfoDWARFTests.dir/DwarfUtils.cpp.o
468.584 [151/616/5698] Building CXX object tools/llvm-reduce/CMakeFiles/llvm-reduce.dir/deltas/SimplifyInstructions.cpp.o
468.965 [151/615/5699] Building CXX object tools/lld/tools/lld/CMakeFiles/lld.dir/lld.cpp.o
469.943 [151/614/5700] Building CXX object unittests/MC/CMakeFiles/MCTests.dir/TargetRegistry.cpp.o

```

</details>

https://github.com/llvm/llvm-project/pull/127063