Add 'third_party/abseil_cpp/' from commit '768eb2ca28'

git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54be
git-subtree-split: 768eb2ca28

third_party/abseil_cpp/absl/debugging/internal/stack_consumption.h

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+//
+// 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
+//
+//      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.
+
+// Helper function for measuring stack consumption of signal handlers.
+
+#ifndef ABSL_DEBUGGING_INTERNAL_STACK_CONSUMPTION_H_
+#define ABSL_DEBUGGING_INTERNAL_STACK_CONSUMPTION_H_
+
+#include "absl/base/config.h"
+
+// The code in this module is not portable.
+// Use this feature test macro to detect its availability.
+#ifdef ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+#error ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION cannot be set directly
+#elif !defined(__APPLE__) && !defined(_WIN32) && \
+    (defined(__i386__) || defined(__x86_64__) || defined(__ppc__))
+#define ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION 1
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace debugging_internal {
+
+// Returns the stack consumption in bytes for the code exercised by
+// signal_handler.  To measure stack consumption, signal_handler is registered
+// as a signal handler, so the code that it exercises must be async-signal
+// safe.  The argument of signal_handler is an implementation detail of signal
+// handlers and should ignored by the code for signal_handler.  Use global
+// variables to pass information between your test code and signal_handler.
+int GetSignalHandlerStackConsumption(void (*signal_handler)(int));
+
+}  // namespace debugging_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+
+#endif  // ABSL_DEBUGGING_INTERNAL_STACK_CONSUMPTION_H_