[compiler-rt] [scudo] Add hooks to mark the range of realloc (PR #74353)

[Christopher Ferris via llvm-commits]

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@@ -73,6 +79,28 @@ __attribute__((visibility("default"))) void __scudo_allocate_hook(void *Ptr,
 __attribute__((visibility("default"))) void __scudo_deallocate_hook(void *Ptr) {
   DC.Ptr = Ptr;
 }
+__attribute__((visibility("default"))) void
+__scudo_realloc_allocate_hook(void *OldPtr, void *NewPtr, size_t Size) {
+  // Verify that __scudo_realloc_deallocate_hook is called first and set the
+  // right pointer.
+  EXPECT_EQ(OldPtr, RC.DeallocPtr);
+  RC.AllocPtr = NewPtr;
+  RC.Size = Size;
+
+  // Note that this is only used for testing. In general, only one pair of hooks
+  // will be invoked in `realloc`. if __scudo_realloc_*_hook are not defined,
+  // it'll call the general hooks only. To make the test easier, we call the
+  // general one here so that either case (wether __scudo_realloc_*_hook are
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cferris1000 wrote:

wether -> whether

https://github.com/llvm/llvm-project/pull/74353