- 45b4111d940009bc7b3ebf621c9cb9293c60344a Use copied value i in lambda by Abseil Team <absl-team@google.com>

  - b726b3102f8439b8480b6ff52fc3660162fa0bd9 Fix MSVC compiler warning on 32-bit platforms (GitHub iss... by Derek Mauro <dmauro@google.com>
  - a8a29e636c85bd7d82c0cbc824a1c2e498764337 Explicitly forbid to specify the template parameter to Wr... by Abseil Team <absl-team@google.com>
  - 566a1d903266fdbfdcf758401c356a0c6703422d Add missing license header to BUILD file. by Alex Strelnikov <strel@google.com>
  - ef1c0642cde0bbad62bbb30715256b232a4ab817 Fix BUILD file header. by Alex Strelnikov <strel@google.com>
  - b6e2cf00f808ee32b9eb7b3226af79d628742c20 Release GraphCycles microbenchmark. by Alex Strelnikov <strel@google.com>
  - f592d78f549e7a242bf2bb4858a26645a655eac3 Release Mutex microbenchmarks. by Alex Strelnikov <strel@google.com>

GitOrigin-RevId: 45b4111d940009bc7b3ebf621c9cb9293c60344a
Change-Id: I82885ae176952a764574c6d4616e312a977407b2

3 files changed, 51 insertions, 0 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 5c05c678..3d3c7aea 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -102,6 +102,7 @@ cc_library(
 cc_library(
     name = "base_internal",
     hdrs = [
+        "internal/hide_ptr.h",
         "internal/identity.h",
         "internal/inline_variable.h",
         "internal/invoke.h",
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 45640562..303533e2 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -36,6 +36,7 @@ list(APPEND BASE_INTERNAL_HEADERS
   "internal/endian.h"
   "internal/exception_testing.h"
   "internal/exception_safety_testing.h"
+  "internal/hide_ptr.h"
   "internal/identity.h"
   "internal/invoke.h"
   "internal/inline_variable.h"
diff --git a/absl/base/internal/hide_ptr.h b/absl/base/internal/hide_ptr.h
new file mode 100644
index 00000000..2c2e11f6
--- /dev/null
+++ b/absl/base/internal/hide_ptr.h
@@ -0,0 +1,49 @@
+// Copyright 2018 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
+//
+//      http://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_HIDE_PTR_H_
+#define ABSL_BASE_INTERNAL_HIDE_PTR_H_
+
+#include <cstdint>
+
+namespace absl {
+namespace base_internal {
+
+// Arbitrary value with high bits set. Xor'ing with it is unlikely
+// to map one valid pointer to another valid pointer.
+constexpr uintptr_t HideMask() {
+  static_assert(sizeof(uintptr_t) == 4 || sizeof(uintptr_t) == 8,
+                "uintptr_t must be 32 or 64 bits");
+  return sizeof(uintptr_t) == 8 ? 0xF03A5F7BF03A5F7BULL : 0xF03A5F7BUL;
+}
+
+// Hide a pointer from the leak checker. For internal use only.
+// Differs from absl::IgnoreLeak(ptr) in that absl::IgnoreLeak(ptr) causes ptr
+// and all objects reachable from ptr to be ignored by the leak checker.
+template <class T>
+inline uintptr_t HidePtr(T* ptr) {
+  return reinterpret_cast<uintptr_t>(ptr) ^ HideMask();
+}
+
+// Return a pointer that has been hidden from the leak checker.
+// For internal use only.
+template <class T>
+inline T* UnhidePtr(uintptr_t hidden) {
+  return reinterpret_cast<T*>(hidden ^ HideMask());
+}
+
+}  // namespace base_internal
+}  // namespace absl
+
+#endif  // ABSL_BASE_INTERNAL_HIDE_PTR_H_