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+// Copyright 2024 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_BASE_INTERNAL_POISON_H_
+#define ABSL_BASE_INTERNAL_POISON_H_
+
+#include <cstdint>
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace base_internal {
+
+inline void* GetBadPointerInternal() {
+ // A likely bad pointer. Pointers are required to have high bits that are all
+ // zero or all one for certain 64-bit CPUs. This pointer value will hopefully
+ // cause a crash on dereference and also be clearly recognizable as invalid.
+ constexpr uint64_t kBadPtr = 0xBAD0BAD0BAD0BAD0;
+ auto ret = reinterpret_cast<void*>(static_cast<uintptr_t>(kBadPtr));
+#ifndef _MSC_VER // MSVC doesn't support inline asm with `volatile`.
+ // Try to prevent the compiler from optimizing out the undefined behavior.
+ asm volatile("" : : "r"(ret) :); // NOLINT
+#endif
+ return ret;
+}
+
+void* InitializePoisonedPointerInternal();
+
+inline void* get_poisoned_pointer() {
+#if defined(NDEBUG) && !defined(ABSL_HAVE_ADDRESS_SANITIZER) && \
+ !defined(ABSL_HAVE_MEMORY_SANITIZER)
+ // In optimized non-sanitized builds, avoid the function-local static because
+ // of the codegen and runtime cost.
+ return GetBadPointerInternal();
+#else
+ // Non-optimized builds may use more robust implementation. Note that we can't
+ // use a static global because Chromium doesn't allow non-constinit globals.
+ static void* ptr = InitializePoisonedPointerInternal();
+ return ptr;
+#endif
+}
+
+} // namespace base_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_BASE_INTERNAL_POISON_H_