[compiler-rt] 6936fad - [compiler-rt] [sanitizer] avoid UB in allocator (#126977)

[via llvm-commits]

Author: Florian Mayer
Date: 2025-02-12T15:49:55-08:00
New Revision: 6936fadfc32023a029ac7ff757bf8f40092ee2b1

URL: https://github.com/llvm/llvm-project/commit/6936fadfc32023a029ac7ff757bf8f40092ee2b1
DIFF: https://github.com/llvm/llvm-project/commit/6936fadfc32023a029ac7ff757bf8f40092ee2b1.diff

LOG: [compiler-rt] [sanitizer] avoid UB in allocator (#126977)

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_allocator_local_cache.h

Removed: 
    


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diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_local_cache.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_local_cache.h
index e495c56f03775..6e54c4852fbb6 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_local_cache.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_local_cache.h
@@ -166,7 +166,7 @@ struct SizeClassAllocator32LocalCache {
       DCHECK_GT(c->count, 0);
     }
     void *res = c->batch[--c->count];
-    PREFETCH(c->batch[c->count - 1]);
+    PREFETCH(c->batch[c->count > 0 ? c->count - 1 : 0]);
     stats_.Add(AllocatorStatAllocated, c->class_size);
     return res;
   }