Export of internal Abseil changes

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1a5831c2b4b85e0151b7952e47f4b80827937620 by Laramie Leavitt <lar@google.com>:

Implement FuzzingBitGen, an adapter which allows existing randomized tests which use absl::BitGenRef to easily integrate with fuzz testing.

I found myself implementing a similar option in our tensorstore project to fuzz test a storage layer and figured that it would be more useful as a common tool with defaults that take the non-random path.

This is similar to the FuzzedDataProvider mechanism which generates random values from a fuzz string, and is used to generate fuzz test inputs, and internally it uses FuzzedDataProvider.

The basic technique used here is to construct mocking lambdas for all of the absl mock distribution configurations, and forwarding the parameters to fuzzing-specific implementations that call into FuzzedDataProvider. The default paths for the distributions are either the bounds or a median value.

PiperOrigin-RevId: 358432715

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e7968538c5ef5cd0b9822dbeac0f659b5e7d49b3 by Derek Mauro <dmauro@google.com>:

Give extern C symbols a unique name when the inline namespace
is given.

This partially addresses #851

PiperOrigin-RevId: 358403842
GitOrigin-RevId: 1a5831c2b4b85e0151b7952e47f4b80827937620
Change-Id: Id5ca0251498e390a8efa7210a17cc2cabb2c7dd8

1 files changed, 4 insertions, 2 deletions

diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 7e66a7d0..30264a3c 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -70,7 +70,9 @@ using absl::synchronization_internal::KernelTimeout;
 using absl::synchronization_internal::PerThreadSem;
 
 extern "C" {
-ABSL_ATTRIBUTE_WEAK void AbslInternalMutexYield() { std::this_thread::yield(); }
+ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalMutexYield)() {
+  std::this_thread::yield();
+}
 }  // extern "C"
 
 namespace absl {
@@ -170,7 +172,7 @@ int MutexDelay(int32_t c, int mode) {
     ABSL_TSAN_MUTEX_PRE_DIVERT(nullptr, 0);
     if (c == limit) {
       // Yield once.
-      AbslInternalMutexYield();
+      ABSL_INTERNAL_C_SYMBOL(AbslInternalMutexYield)();
       c++;
     } else {
       // Then wait.