Set a fixed scratch register for ARM code generation

r9 is now set as a fixed scratch register for ARM code generation. removed some unneeded allocation of temporary registers and use the scratch register instead.
Review URL: http://codereview.chromium.org/5976014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6162 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/assembler-arm.h

@@ -66,13 +66,14 @@ namespace internal {
 // such that we use an enum in optimized mode, and the struct in debug
 // mode. This way we get the compile-time error checking in debug mode
 // and best performance in optimized code.
-//
+
 // Core register
 struct Register {
   static const int kNumRegisters = 16;
   static const int kNumAllocatableRegisters = 8;
 
   static int ToAllocationIndex(Register reg) {
+    ASSERT(reg.code() < kNumAllocatableRegisters);
     return reg.code();
   }
 
@@ -132,7 +133,7 @@ const Register r5  = {  5 };
 const Register r6  = {  6 };
 const Register r7  = {  7 };
 const Register r8  = {  8 };  // Used as context register.
-const Register r9  = {  9 };
+const Register r9  = {  9 };  // Used as lithium codegen scratch register.
 const Register r10 = { 10 };  // Used as roots register.
 const Register fp  = { 11 };
 const Register ip  = { 12 };

src/arm/lithium-arm.cc

@@ -1222,7 +1222,6 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
       ASSERT(compare->value()->representation().IsTagged());
 
       return new LHasInstanceTypeAndBranch(UseRegisterAtStart(compare->value()),
-                                           TempRegister(),
                                            first_id,
                                            second_id);
     } else if (v->IsHasCachedArrayIndex()) {
@@ -1235,11 +1234,8 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
       HIsNull* compare = HIsNull::cast(v);
       ASSERT(compare->value()->representation().IsTagged());
 
-      // We only need a temp register for non-strict compare.
-      LOperand* temp = compare->is_strict() ? NULL : TempRegister();
       return new LIsNullAndBranch(UseRegisterAtStart(compare->value()),
                                   compare->is_strict(),
-                                  temp,
                                   first_id,
                                   second_id);
     } else if (v->IsIsObject()) {
@@ -1851,8 +1847,7 @@ LInstruction* LChunkBuilder::DoLoadNamedGeneric(HLoadNamedGeneric* instr) {
 LInstruction* LChunkBuilder::DoLoadFunctionPrototype(
     HLoadFunctionPrototype* instr) {
   return AssignEnvironment(DefineAsRegister(
-      new LLoadFunctionPrototype(UseRegister(instr->function()),
-                                 TempRegister())));
+      new LLoadFunctionPrototype(UseRegister(instr->function()))));
 }
 
 

src/arm/lithium-arm.h

@@ -726,11 +726,9 @@ class LIsNullAndBranch: public LIsNull {
  public:
   LIsNullAndBranch(LOperand* value,
                    bool is_strict,
-                   LOperand* temp,
                    int true_block_id,
                    int false_block_id)
       : LIsNull(value, is_strict),
-        temp_(temp),
         true_block_id_(true_block_id),
         false_block_id_(false_block_id) { }
 
@@ -741,10 +739,7 @@ class LIsNullAndBranch: public LIsNull {
   int true_block_id() const { return true_block_id_; }
   int false_block_id() const { return false_block_id_; }
 
-  LOperand* temp() const { return temp_; }
-
  private:
-  LOperand* temp_;
   int true_block_id_;
   int false_block_id_;
 };
@@ -839,11 +834,9 @@ class LHasInstanceType: public LUnaryOperation {
 class LHasInstanceTypeAndBranch: public LHasInstanceType {
  public:
   LHasInstanceTypeAndBranch(LOperand* value,
-                            LOperand* temporary,
                             int true_block_id,
                             int false_block_id)
       : LHasInstanceType(value),
-        temp_(temporary),
         true_block_id_(true_block_id),
         false_block_id_(false_block_id) { }
 
@@ -855,10 +848,7 @@ class LHasInstanceTypeAndBranch: public LHasInstanceType {
   int true_block_id() const { return true_block_id_; }
   int false_block_id() const { return false_block_id_; }
 
-  LOperand* temp() { return temp_; }
-
  private:
-  LOperand* temp_;
   int true_block_id_;
   int false_block_id_;
 };
@@ -1263,17 +1253,12 @@ class LLoadNamedGeneric: public LUnaryOperation {
 
 class LLoadFunctionPrototype: public LUnaryOperation {
  public:
-  LLoadFunctionPrototype(LOperand* function, LOperand* temporary)
-      : LUnaryOperation(function), temporary_(temporary) { }
+  LLoadFunctionPrototype(LOperand* function) : LUnaryOperation(function) { }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadFunctionPrototype, "load-function-prototype")
   DECLARE_HYDROGEN_ACCESSOR(LoadFunctionPrototype)
 
   LOperand* function() const { return input(); }
-  LOperand* temporary() const { return temporary_; }
-
- private:
-  LOperand* temporary_;
 };
 
 

src/arm/lithium-codegen-arm.h

@@ -103,6 +103,8 @@ class LCodeGen BASE_EMBEDDED {
   HGraph* graph() const { return chunk_->graph(); }
   MacroAssembler* masm() const { return masm_; }
 
+  Register scratch0() { return r9; }
+
   int GetNextEmittedBlock(int block);
   LInstruction* GetNextInstruction();