Export of internal Abseil changes

--
f4c7e510922668c68be4aa79a00867c3d3ca9f95 by Derek Mauro <dmauro@google.com>:

Many improvements to LeakChecker builds

The presence of the LeakChecker is now detected when possible. GCC
users using LeakChecker in standalone mode still need to use
-DLEAK_CHECKER. This is now documented in the header.

The hacky targets used for testing leak checking have been removed in
favor of testing in AddressSanitizer mode on Kokoro.

Fixes #885
Fixes #1153

PiperOrigin-RevId: 441203393
Change-Id: Ibe64ef6b104bcaf31839ff7184e558cc86abdd1c

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5c70a23aa83b8152ab95d2cf21662fc63c80ef7d by Abseil Team <absl-team@google.com>:

Add a benchmark for stacktrace

PiperOrigin-RevId: 441196473
Change-Id: I4c9aa2e797aa2cae09abfaaee3abe5c09eb62fc4

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50b406052273b9d5bad04a7860a96e4d5d956c02 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 441114481
Change-Id: I667af7a50d5631ca91289dd24c91ba90233e0184

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568b4eaac120b420bce5290179d407d2b57d5bae by Dino Radakovic <dinor@google.com>:

Internal change

PiperOrigin-RevId: 440894155
Change-Id: Ia587ffc65a8321126585fb363b7c0ca8cc2a0da2

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d53948eace4f3a10ac5a6c1496dc51b81adc412c by Abseil Team <absl-team@google.com>:

Explicitly give internal linkage to symbols which are not used outside of their
translation units.

PiperOrigin-RevId: 440424519
Change-Id: I531c5e229d443375483b7550a34f48042589a99b
GitOrigin-RevId: f4c7e510922668c68be4aa79a00867c3d3ca9f95

1 files changed, 55 insertions, 0 deletions

diff --git a/absl/debugging/stacktrace_benchmark.cc b/absl/debugging/stacktrace_benchmark.cc
new file mode 100644
index 00000000..9360bafe
--- /dev/null
+++ b/absl/debugging/stacktrace_benchmark.cc
@@ -0,0 +1,55 @@
+// Copyright 2022 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.
+
+#include "absl/base/attributes.h"
+#include "absl/base/config.h"
+#include "absl/base/optimization.h"
+#include "absl/debugging/stacktrace.h"
+#include "benchmark/benchmark.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace {
+
+static constexpr int kMaxStackDepth = 100;
+static constexpr int kCacheSize = (1 << 16);
+void* pcs[kMaxStackDepth];
+
+ABSL_ATTRIBUTE_NOINLINE void func(benchmark::State& state, int x, int depth) {
+  if (x <= 0) {
+    // Touch a significant amount of memory so that the stack is likely to be
+    // not cached in the L1 cache.
+    state.PauseTiming();
+    int* arr = new int[kCacheSize];
+    for (int i = 0; i < kCacheSize; ++i) benchmark::DoNotOptimize(arr[i] = 100);
+    delete[] arr;
+    state.ResumeTiming();
+    benchmark::DoNotOptimize(absl::GetStackTrace(pcs, depth, 0));
+    return;
+  }
+  ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
+  func(state, --x, depth);
+}
+
+void BM_GetStackTrace(benchmark::State& state) {
+  int depth = state.range(0);
+  for (auto s : state) {
+    func(state, depth, depth);
+  }
+}
+
+BENCHMARK(BM_GetStackTrace)->DenseRange(10, kMaxStackDepth, 10);
+}  // namespace
+ABSL_NAMESPACE_END
+}  // namespace absl