From b35973e3e35cb1eccb086d6a549c253c49579474 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Fri, 17 Apr 2020 08:13:06 -0700 Subject: Export of internal Abseil changes -- d857e6e1f9b09a3eb5abd890677a98b23346f07a by Abseil Team : Simplify internal TryAcquireWithSpinning. No point declaring the `result` variable: we can just return the results directly. PiperOrigin-RevId: 307045800 -- 421952252bc23be51f47f7d23f3422bad1ed382c by Derek Mauro : Add custom sink support for `absl::Format()` through an ADL extension mechanism. Users can now define `void AbslFormatFlush(MySink* dest, absl::string_view part)` to allow `absl::Format()` to append to a custom sink. PiperOrigin-RevId: 306929052 -- c73d5cdb62cd58ea421ed1aeeab78a0ffcfeeefb by Matt Calabrese : Internal-only conformance-testing macro ABSL_INTERNAL_ASSERT_CONFORMANCE_OF for compile-time and runtime checks of a specified type, expected properties of that type, and a logically-ordered series of equivalence classes of that type. PiperOrigin-RevId: 306885512 -- a8c2495a07f37d68907855e3f0535bd5c27a3b52 by Abseil Team : Internal change PiperOrigin-RevId: 306766753 GitOrigin-RevId: d857e6e1f9b09a3eb5abd890677a98b23346f07a Change-Id: Ic23c92ac74f9ffcbb2471ff8c6691f4b7b20354b --- absl/synchronization/mutex.cc | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'absl/synchronization/mutex.cc') diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc index 6ee5f235..8cda5a1c 100644 --- a/absl/synchronization/mutex.cc +++ b/absl/synchronization/mutex.cc @@ -1439,20 +1439,18 @@ void Mutex::AssertNotHeld() const { // may spin for a short while if the lock cannot be acquired immediately. static bool TryAcquireWithSpinning(std::atomic* mu) { int c = mutex_globals.spinloop_iterations; - int result = -1; // result of operation: 0=false, 1=true, -1=unknown - do { // do/while somewhat faster on AMD intptr_t v = mu->load(std::memory_order_relaxed); - if ((v & (kMuReader|kMuEvent)) != 0) { // a reader or tracing -> give up - result = 0; + if ((v & (kMuReader|kMuEvent)) != 0) { + return false; // a reader or tracing -> give up } else if (((v & kMuWriter) == 0) && // no holder -> try to acquire mu->compare_exchange_strong(v, kMuWriter | v, std::memory_order_acquire, std::memory_order_relaxed)) { - result = 1; + return true; } - } while (result == -1 && --c > 0); - return result == 1; + } while (--c > 0); + return false; } ABSL_XRAY_LOG_ARGS(1) void Mutex::Lock() { -- cgit v1.2.3