[PATCH] D153471: [lsan][Darwin] Unconditionally strip high bits from potential pointers

[Leonard Grey via Phabricator via llvm-commits]

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The method cache stashes a mask in the high bits under some circumstances:
https://github.com/apple-oss-distributions/objc4/blob/689525d556eb3dee1ffb700423bccf5ecc501dbf/runtime/objc-cache.mm#L589

I'm hitting this now on macOS 13.4 arm64, so we can no longer rely on `OBJC_DATA_MASK` to identify potential pointers that need to be transformed


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D153471

Files:
  compiler-rt/lib/lsan/lsan_common.cpp


Index: compiler-rt/lib/lsan/lsan_common.cpp
===================================================================
--- compiler-rt/lib/lsan/lsan_common.cpp
+++ compiler-rt/lib/lsan/lsan_common.cpp
@@ -177,9 +177,7 @@
 // they need to be transformed back into something that looks like a pointer.
 static inline void *MaybeTransformPointer(void *p) {
   uptr ptr = reinterpret_cast<uptr>(p);
-  if ((ptr & OBJC_FAST_IS_RW) == OBJC_FAST_IS_RW)
-    ptr &= OBJC_DATA_MASK;
-  return reinterpret_cast<void *>(ptr);
+  return reinterpret_cast<void *>(ptr & OBJC_DATA_MASK);
 }
 #  endif
 


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