[sanitizer] Allow *___lcxx_override symbolse in symbolizer

[vitalybuka]

We don't intercept them, and they are not called and used only as
markers anyway.

These symbols introduced with #69498.

[llvmbot]

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

Author: Vitaly Buka (vitalybuka)

Changes

We don't intercept them, and they are not called and used only as
markers anyway.

---

Full diff: https://github.com/llvm/llvm-project/pull/79904.diff

2 Files Affected:

• (modified) compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh (+4-2)
• (modified) compiler-rt/lib/sanitizer_common/symbolizer/scripts/global_symbols.txt (+5)

diff --git a/compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh b/compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh
index f24d42cc84e4176..7f4082a6cd190e2 100755
--- a/compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh
+++ b/compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh
@@ -191,8 +191,10 @@ $OPT -passes=internalize -internalize-public-api-list=${SYMBOLIZER_API_LIST} all
 $CC $FLAGS -fno-lto -c opt.bc -o symbolizer.o
 
 echo "Checking undefined symbols..."
-nm -f posix -g symbolizer.o | cut -f 1,2 -d \  | LC_COLLATE=C sort -u > undefined.new
-(diff -u $SCRIPT_DIR/global_symbols.txt undefined.new | grep -E "^\+[^+]") && \
+export LC_ALL=C
+nm -f posix -g symbolizer.o | cut -f 1,2 -d \  | sort -u > undefined.new
+grep -Ev "^#|^$" $SCRIPT_DIR/global_symbols.txt | sort -u > expected.new
+(diff -u expected.new undefined.new | grep -E "^\+[^+]") && \
   (echo "Failed: unexpected symbols"; exit 1)
 
 cp -f symbolizer.o $OUTPUT
diff --git a/compiler-rt/lib/sanitizer_common/symbolizer/scripts/global_symbols.txt b/compiler-rt/lib/sanitizer_common/symbolizer/scripts/global_symbols.txt
index 0a4bc6989a0d72a..ef522976a2c2da3 100644
--- a/compiler-rt/lib/sanitizer_common/symbolizer/scripts/global_symbols.txt
+++ b/compiler-rt/lib/sanitizer_common/symbolizer/scripts/global_symbols.txt
@@ -1,3 +1,6 @@
+# This file is used to control symbols used by internal symbolizer. We want to
+# avoid unexpected dependency on function intercepted by sanitizers.
+
 _GLOBAL_OFFSET_TABLE_ U
 _ZN11__sanitizer13internal_mmapEPvjiiiy U
 _ZN11__sanitizer13internal_mmapEPvmiiiy U
@@ -62,6 +65,8 @@ __sanitizer_symbolize_flush T
 __sanitizer_symbolize_frame T
 __sanitizer_symbolize_set_demangle T
 __sanitizer_symbolize_set_inline_frames T
+__start___lcxx_override U
+__stop___lcxx_override U
 __strdup U
 __udivdi3 U
 __umoddi3 U

[vitalybuka]

Please don't merge yet, testing

And I don't know why bots are inconsistent, I would expect that all fail without this patch.

[thurstond]

@kstoimenov (build watch): FYI: these symbols appear in the alternating buildbot failures