Core dump running iwyu on bazel sources

[katre]

When testing iwyu v0.0.4 on the Bazel sources, I got a crash dump from inside clang.

Environment:

This is on an amd64 Dell laptop running Ubuntu 24.04. Bazel is from head and tests are using Bazel 9.1.0.

Reproduction:

Bazel commit: bazelbuild/bazel@3c2c7cf

Add bazel-iwyu:

 git diff 3c2c7cf23ca9b83d23800fc19ee1e55ec2c12f38
diff --git a/MODULE.bazel b/MODULE.bazel
index 15b177f90d..c9e57eebd3 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -494,3 +494,6 @@ register_toolchains("@local_config_winsdk//:all")
 register_toolchains("//src/main/res:empty_rc_toolchain")
 
 register_toolchains("@graalvm_ce_toolchains//:gvm")
+
+# ICYU
+bazel_dep(name = "bazel_iwyu", version = "0.0.4")

Run iwyu on //src/main/cpp:rc_file:

$ bazel build --compilation_mode=dbg --host_compilation_mode=dbg  --aspects @bazel_iwyu//:iwyu.bzl%iwyu_aspect --output_groups=report -s -- //src/main/cpp:rc_file 
INFO: Analyzed target //src/main/cpp:rc_file (90 packages loaded, 3271 targets configured, 1 aspect application).
SUBCOMMAND: # aspects [@@bazel_iwyu+//bazel/iwyu:iwyu.bzl%iwyu_aspect] on cc_library rule target //src/main/cpp:rc_file [action 'Run include-what-you-use on src/main/cpp/rc_file.cc', configuration: 0fcdb6284b9e2b9f5f620fe4086f538394a679570c6f76470a1d9f540fcf2dae, execution platform: //:default_host_platform, mnemonic: iwyu]
(cd /home/jcater/.cache/bazel/_bazel_jcater/c3f78d9b26355df6196e2a7ad0273cae/execroot/_main && \
  exec env - \
  bazel-out/k8-dbg/bin/external/bazel_iwyu+/bazel/iwyu/iwyu_prebuilt_toolchain_impl_wrapper.sh bazel-out/k8-dbg/bin/src/main/cpp/rc_file.rc_file.cc.iwyu.txt -Xiwyu --cxx17ns -Xiwyu '--error=1' -Xiwyu '--max_line_length=127' -Xiwyu --no_fwd_decls -Xiwyu --transitive_includes_only -Xiwyu '--mapping_file=external/bazel_iwyu+/mappings/gtest.imp' -U_FORTIFY_SOURCE -fstack-protector -Wall -Wunused-but-set-parameter -Wno-free-nonheap-object -fno-omit-frame-pointer -g '-std=c++17' -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' -x c++ -DBLAZE_OPENSOURCE -iquote . -iquote bazel-out/k8-dbg/bin -iquote external/abseil-cpp+ -iquote bazel-out/k8-dbg/bin/external/abseil-cpp+ -iquote external/re2+ -iquote bazel-out/k8-dbg/bin/external/re2+ src/main/cpp/rc_file.cc)
# Configuration: 0fcdb6284b9e2b9f5f620fe4086f538394a679570c6f76470a1d9f540fcf2dae
# Execution platform: //:default_host_platform
# Runner: processwrapper-sandbox
ERROR: /home/jcater/src/bazel/bazel/src/main/cpp/BUILD:264:11: Run include-what-you-use on src/main/cpp/rc_file.cc failed: (Exit 1): iwyu_prebuilt_toolchain_impl_wrapper.sh failed: error executing iwyu command (from aspects [@@bazel_iwyu+//bazel/iwyu:iwyu.bzl%iwyu_aspect] on cc_library rule target //src/main/cpp:rc_file) bazel-out/k8-dbg/bin/external/bazel_iwyu+/bazel/iwyu/iwyu_prebuilt_toolchain_impl_wrapper.sh bazel-out/k8-dbg/bin/src/main/cpp/rc_file.rc_file.cc.iwyu.txt -Xiwyu --cxx17ns -Xiwyu '--error=1' -Xiwyu ... (remaining 35 arguments skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
bazel-out/k8-dbg/bin/external/bazel_iwyu+/bazel/iwyu/iwyu_prebuilt_toolchain_impl_wrapper.sh: line 23: 199561 Segmentation fault      (core dumped) "${IWYU_BINARY}" -Xclang -resource-dir -Xclang "external/bazel_iwyu++iwyu+iwyu_prebuilt_pkg/lib/clang/22" "$@" 2> "${OUTPUT}"
[ERROR] IWYU violation found. Fixes have been written to bazel-out/k8-dbg/bin/src/main/cpp/rc_file.rc_file.cc.iwyu.txt
Aspect @@bazel_iwyu+//bazel/iwyu:iwyu.bzl%iwyu_aspect of //src/main/cpp:rc_file failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 2.636s, Critical Path: 1.49s
INFO: 2 processes: 1 action cache hit, 2 internal.
ERROR: Build did NOT complete successfully

Core dump

I was able to find the core file and extract a backtrace. I've attached the entire trace, but here's the start:

backtrace:
Core was generated by `external/bazel_iwyu++iwyu+iwyu_prebuilt_pkg/bin/include-what-you-use -Xclang -r'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00006216dc3ef261 in clang::Decl::getASTContext() const ()
(gdb) bt
#0  0x00006216dc3ef261 in clang::Decl::getASTContext() const ()
#1  0x00006216d9e6af32 in include_what_you_use::GetWrittenQualifiedNameAsString[abi:cxx11](clang::NamedDecl const*, bool) ()
#2  0x00006216d9f2b06c in include_what_you_use::FullUseCache::GetPrecomputedResugarMap(clang::TemplateSpecializationType const*, clang::LangOptions const&) ()
#3  0x00006216d9dca4e2 in include_what_you_use::InstantiatedTemplateVisitor::ReplayClassMemberUsesFromPrecomputedList(clang::TemplateSpecializationType const*) ()
#4  0x00006216d9dca3c4 in include_what_you_use::InstantiatedTemplateVisitor::TraverseDataAndTypeMembersOfClassHelper(clang::TemplateSpecializationType const*) ()
#5  0x00006216d9dcb3d8 in include_what_you_use::BaseAstVisitor<include_what_you_use::InstantiatedTemplateVisitor>::TraverseTypeLoc(clang::TypeLoc, bool) ()
#6  0x00006216d9dd4142 in clang::RecursiveASTVisitor<include_what_you_use::InstantiatedTemplateVisitor>::TraverseNestedNameSpecifierLoc(clang::NestedNameSpecifierLoc) ()
#7  0x00006216d9dd3ec4 in include_what_you_use::BaseAstVisitor<include_what_you_use::InstantiatedTemplateVisitor>::TraverseNestedNameSpecifierLoc(clang::NestedNameSpecifierLoc) ()
#8  0x00006216d9ddc8fe in clang::RecursiveASTVisitor<include_what_you_use::InstantiatedTemplateVisitor>::TraverseDependentScopeDeclRefExpr(clang::DependentScopeDeclRefExpr*, llvm::SmallVectorImpl<llvm::PointerIntPair<clang::Stmt*, 1u, bool, llvm::PointerLikeTypeTraits<clang::Stmt*>, llvm::PointerIntPairInfo<clang::Stmt*, 1u, llvm::PointerLikeTypeTraits<clang::Stmt*> > > >*) ()
#9  0x00006216d9dd7c4f in clang::RecursiveASTVisitor<include_what_you_use::InstantiatedTemplateVisitor>::TraverseStmt(clang::Stmt*, llvm::SmallVectorImpl<llvm::PointerIntPair<clang::Stmt*, 1u, bool, llvm::PointerLikeTypeTraits<clang::Stmt*>, llvm::PointerIntPairInfo<clang::Stmt*, 1u, llvm::PointerLikeTypeTraits<clang::Stmt*> > > >*) ()

Let me know if you need more details.

iwyu-crash.log