Make absl::synchronization more compatible with Starboard

third_party/abseil-cpp/absl/base/BUILD.gn

@@ -46,6 +46,7 @@ absl_source_set("spinlock_wait") {
     "internal/spinlock_akaros.inc",
     "internal/spinlock_linux.inc",
     "internal/spinlock_posix.inc",
+    "internal/spinlock_starboard.inc",
     "internal/spinlock_wait.cc",
     "internal/spinlock_win32.inc",
   ]
@@ -54,6 +55,7 @@ absl_source_set("spinlock_wait") {
     ":base_internal",
     ":core_headers",
     ":errno_saver",
+    "//starboard:starboard_headers_only",
   ]
   visibility = [ "//third_party/abseil-cpp/absl/base:*" ]
 }

third_party/abseil-cpp/absl/base/internal/spinlock_starboard.inc

@@ -0,0 +1,46 @@
+// Copyright 2017 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.
+//
+// This file is a Posix-specific part of spinlock_wait.cc
+
+#if defined(STARBOARD)
+#include "starboard/thread.h"
+
+#include <atomic>
+#include <ctime>
+
+#include "absl/base/internal/errno_saver.h"
+#include "absl/base/internal/scheduling_mode.h"
+#include "absl/base/port.h"
+
+extern "C" {
+
+ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
+    std::atomic<uint32_t>* /* lock_word */, uint32_t /* value */, int loop,
+    absl::base_internal::SchedulingMode /* mode */) {
+  absl::base_internal::ErrnoSaver errno_saver;
+  if (loop == 0) {
+  } else if (loop == 1) {
+    SbThreadYield();
+  } else {
+    SbThreadSleep(loop);
+  }
+}
+
+ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
+    std::atomic<uint32_t>* /* lock_word */, bool /* all */) {}
+
+}  // extern "C"
+
+#endif

third_party/abseil-cpp/absl/base/internal/spinlock_wait.cc

@@ -22,7 +22,7 @@
 #include "absl/base/internal/spinlock_wait.h"
 
 #if defined(STARBOARD)
-#include "absl/base/internal/spinlock_posix.inc"
+#include "absl/base/internal/spinlock_starboard.inc"
 #elif defined(_WIN32)
 #include "absl/base/internal/spinlock_win32.inc"
 #elif defined(__linux__)

third_party/abseil-cpp/absl/synchronization/internal/futex.h

@@ -44,7 +44,7 @@
 // Bionic supports all the futex operations we need even when some of the futex
 // definitions are missing.
 #define ABSL_INTERNAL_HAVE_FUTEX
-#elif defined(__linux__) && defined(FUTEX_CLOCK_REALTIME)
+#elif defined(__linux__) && defined(FUTEX_CLOCK_REALTIME) && !defined(STARBOARD)
 // FUTEX_CLOCK_REALTIME requires Linux >= 2.6.28.
 #define ABSL_INTERNAL_HAVE_FUTEX
 #endif