Support conversion of clamped double values for pixel arrays in Crankshaft.

src/arm/lithium-arm.h

 // Copyright 2011 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 55 matching lines @@
   V(CallNamed)                                  \
   V(CallNew)                                    \
   V(CallRuntime)                                \
   V(CallStub)                                   \
   V(CheckFunction)                              \
   V(CheckInstanceType)                          \
   V(CheckNonSmi)                                \
   V(CheckMap)                                   \
   V(CheckPrototypeMaps)                         \
   V(CheckSmi)                                   \
+  V(ClampDoubleToUint8)                         \
+  V(ClampIToUint8)                              \

[Kevin Millikin (Chromium), 2011/05/16 07:06:34]

It's strange that there is "Double", "I", and "Tagged" :)  I suggest "D", "I",
and "T" so the class names match the printed instruction names.

+  V(ClampTaggedToUint8)                         \
   V(ClassOfTest)                                \
   V(ClassOfTestAndBranch)                       \
   V(CmpID)                                      \
   V(CmpIDAndBranch)                             \
   V(CmpJSObjectEq)                              \
   V(CmpJSObjectEqAndBranch)                     \
   V(CmpMapAndBranch)                            \
   V(CmpSymbolEq)                                \
   V(CmpSymbolEqAndBranch)                       \
   V(CmpT)                                       \
@@ skipping 1834 matching lines @@
 class LCheckNonSmi: public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LCheckNonSmi(LOperand* value) {
     inputs_[0] = value;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckNonSmi, "check-non-smi")
 };
 
 
+class LClampDoubleToUint8: public LTemplateInstruction<1, 1, 1> {
+ public:
+  explicit LClampDoubleToUint8(LOperand* value, LOperand* temp) {

[Kevin Millikin (Chromium), 2011/05/16 07:06:34]

No need for explicit here.

+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  LOperand* unclamped() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(ClampDoubleToUint8, "clamp-d-to-uint8")
+};
+
+
+class LClampIToUint8: public LTemplateInstruction<1, 1, 0> {
+ public:
+  explicit LClampIToUint8(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  LOperand* unclamped() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(ClampIToUint8, "clamp-i-to-uint8")
+};
+
+
+class LClampTaggedToUint8: public LTemplateInstruction<1, 1, 1> {
+ public:
+  explicit LClampTaggedToUint8(LOperand* value, LOperand* temp) {
+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  LOperand* unclamped() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(ClampTaggedToUint8, "clamp-t-to-uint8")
+};
+
+
 class LArrayLiteral: public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ArrayLiteral, "array-literal")
   DECLARE_HYDROGEN_ACCESSOR(ArrayLiteral)
 };
 
 
 class LObjectLiteral: public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ObjectLiteral, "object-literal")
@@ skipping 358 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_ARM_H_