[MSan] Pass -fsanitize-ignorelist to the instrumented libcxxabi

[arichardson]

This ensures that the MSan unit tests are able to pass with an
uninstrumented libunwind. We need to avoid instrumentation for
__gxx_personality_v0, which is part of the default msan_ignorelist.txt
that is installed into the resource directory. However, if we are trying
to test the just-built libraries, this global ignore list may not be
present yet, so we still instrument the function.

Arguably this function should not be on the default ignore list since it
is only a problem when building libcxxabi with MSan instrumentation and
without an instrumented libunwind, so maybe the logic should really be
part of the libcxxabi build. However, that could be done as a follow-up.

See 2f856a3 for more context.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Alexander Richardson (arichardson)

Changes

This ensures that the MSan unit tests are able to pass with an
uninstrumented libunwind. We need to avoid instrumentation for
__gxx_personality_v0, which is part of the default msan_ignorelist.txt
that is installed into the resource directory. However, if we are trying
to test the just-built libraries, this global ignore list may not be
present yet, so we still instrument the function.

Arguably this function should not be on the default ignore list since it
is only a problem when building libcxxabi with MSan instrumentation and
without an instrumented libunwind, so maybe the logic should really be
part of the libcxxabi build. However, that could be done as a follow-up.

See 2f856a3 for more context.

---

Full diff: https://github.com/llvm/llvm-project/pull/83652.diff

1 Files Affected:

• (modified) compiler-rt/lib/msan/tests/CMakeLists.txt (+2-1)

diff --git a/compiler-rt/lib/msan/tests/CMakeLists.txt b/compiler-rt/lib/msan/tests/CMakeLists.txt
index 0d43f432ab6a37..4f09f1e6a691fa 100644
--- a/compiler-rt/lib/msan/tests/CMakeLists.txt
+++ b/compiler-rt/lib/msan/tests/CMakeLists.txt
@@ -10,7 +10,8 @@ set(MSAN_LIBCXX_CFLAGS
   -fsanitize-memory-track-origins
   -fno-sanitize-memory-param-retval  # unittests test mostly this mode.
   -Wno-pedantic
-  -Xclang -fdepfile-entry=${COMPILER_RT_OUTPUT_DIR}/share/msan_ignorelist.txt
+    # Do not instrument __gxx_personality_v0 (part of libcxxabi)
+  -fsanitize-ignorelist=${COMPILER_RT_OUTPUT_DIR}/share/msan_ignorelist.txt
   )
 
 # Unittest sources and build flags.