Support inlining and crankshaft optimization of Math.random.

src/hydrogen-instructions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 128 matching lines @@
   V(LoadNamedGeneric)                          \
   V(Mod)                                       \
   V(Mul)                                       \
   V(ObjectLiteralFast)                         \
   V(ObjectLiteralGeneric)                      \
   V(OsrEntry)                                  \
   V(OuterContext)                              \
   V(Parameter)                                 \
   V(Power)                                     \
   V(PushArgument)                              \
+  V(Random)                                    \
   V(RegExpLiteral)                             \
   V(Return)                                    \
   V(Sar)                                       \
   V(Shl)                                       \
   V(Shr)                                       \
   V(Simulate)                                  \
   V(SoftDeoptimize)                            \
   V(StackCheck)                                \
   V(StoreContextSlot)                          \
   V(StoreGlobalCell)                           \
@@ skipping 2832 matching lines @@
       : Representation::None();
   }
 
   DECLARE_CONCRETE_INSTRUCTION(Power)
 
  protected:
   virtual bool DataEquals(HValue* other) { return true; }
 };
 
 
+class HRandom: public HTemplateInstruction<1> {
+ public:
+  explicit HRandom(HValue* global_object) {
+    SetOperandAt(0, global_object);
+    set_representation(Representation::Double());
+  }
+
+  HValue* global_object() { return OperandAt(0); }
+
+  virtual Representation RequiredInputRepresentation(int index) {
+    return index == 0
+        ? Representation::Tagged()
+        : Representation::None();

[Jakob Kummerow, 2012/01/11 08:10:40]

"return Representation::Tagged();" should suffice, as index == 0 is always true.

[Mads Ager (chromium), 2012/01/11 10:24:46]

Done.

+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(Random)
+};
+
+
 class HAdd: public HArithmeticBinaryOperation {
  public:
   HAdd(HValue* context, HValue* left, HValue* right)
       : HArithmeticBinaryOperation(context, left, right) {
     SetFlag(kCanOverflow);
   }
 
   // Add is only commutative if two integer values are added and not if two
   // tagged values are added (because it might be a String concatenation).
   virtual bool IsCommutative() const {
@@ skipping 1488 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_