Reland r17877 - Introduce a v8::Platform class that bundles embedder callbacks

include/v8-platform.h

Index: include/v8-platform.h
diff --git a/src/hydrogen-bce.h b/include/v8-platform.h
similarity index 58%
copy from src/hydrogen-bce.h
copy to include/v8-platform.h
index c55dea7b7a5133b62b0e4fa81f1e4b3fa3022279..4fb8e6433544dffe0bf27411d9174fd9425b835b 100644
--- a/src/hydrogen-bce.h
+++ b/include/v8-platform.h
@@ -25,50 +25,51 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#ifndef V8_HYDROGEN_BCE_H_
-#define V8_HYDROGEN_BCE_H_
+#ifndef V8_V8_PLATFORM_H_
+#define V8_V8_PLATFORM_H_
 
-#include "hydrogen.h"
+#include "v8.h"
 
 namespace v8 {
-namespace internal {
 
-
-class BoundsCheckBbData;
-class BoundsCheckKey;
-class BoundsCheckTable : private ZoneHashMap {
+/**
+ * A Task represents a unit of work.
+ */
+class Task {
  public:
-  explicit BoundsCheckTable(Zone* zone);
-
-  INLINE(BoundsCheckBbData** LookupOrInsert(BoundsCheckKey* key, Zone* zone));
-  INLINE(void Insert(BoundsCheckKey* key, BoundsCheckBbData* data, Zone* zone));
-  INLINE(void Delete(BoundsCheckKey* key));
+  virtual ~Task() {}
 
- private:
-  DISALLOW_COPY_AND_ASSIGN(BoundsCheckTable);
+  virtual void Run() = 0;
 };
 
-
-class HBoundsCheckEliminationPhase : public HPhase {
+/**
+ * V8 Platform abstraction layer.
+ *
+ * The embedder has to provide an implementation of this interface before
+ * initializing the rest of V8.
+ */
+class Platform {
  public:
-  explicit HBoundsCheckEliminationPhase(HGraph* graph)
-      : HPhase("H_Bounds checks elimination", graph), table_(zone()) { }
-
-  void Run() {
-    EliminateRedundantBoundsChecks(graph()->entry_block());
-  }
-
- private:
-  void EliminateRedundantBoundsChecks(HBasicBlock* bb);
-  BoundsCheckBbData* PreProcessBlock(HBasicBlock* bb);
-  void PostProcessBlock(HBasicBlock* bb, BoundsCheckBbData* data);
-
-  BoundsCheckTable table_;
-
-  DISALLOW_COPY_AND_ASSIGN(HBoundsCheckEliminationPhase);
+  /**
+   * Schedules a task to be invoked on a background thread. |task_is_slow|
+   * indicates that the task will run a long time. The Platform implementation
+   * takes ownership of |task|. There is no guarantee about order of execution
+   * of tasks wrt order of scheduling, nor is there a guarantee about the
+   * thread the task will be run on.
+   */
+  virtual void CallOnBackgroundThread(Task* task, bool task_is_slow) = 0;
+
+  /**
+   * Schedules a task to be invoked on a foreground thread wrt a specific
+   * |isolate|. Tasks posted for the same isolate should be execute in order of
+   * scheduling. The definition of "foreground" is opaque to V8.
+   */
+  virtual void CallOnForegroundThread(Isolate* isolate, Task* task) = 0;
+
+ protected:
+  virtual ~Platform() {}
 };
 
+}  // namespace v8
 
-} }  // namespace v8::internal
-
-#endif  // V8_HYDROGEN_BCE_H_
+#endif  // V8_V8_PLATFORM_H_