X64: Added register holding Smi::FromInt(1).

src/x64/macro-assembler-x64.h

 // Copyright 2009 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 29 matching lines @@
   // Return the pointer to the allocated already tagged as a heap object.
   TAG_OBJECT = 1 << 0,
   // The content of the result register already contains the allocation top in
   // new space.
   RESULT_CONTAINS_TOP = 1 << 1
 };
 
 // Default scratch register used by MacroAssembler (and other code that needs
 // a spare register). The register isn't callee save, and not used by the
 // function calling convention.
-static const Register kScratchRegister = { 10 };  // r10.
-static const Register kRootRegister = { 13 };     // r13
+static const Register kScratchRegister = { 10 };      // r10.
+static const Register kSmiConstantRegister = { 15 };  // r15 (callee save).
+static const Register kRootRegister = { 13 };         // r13 (callee save).
+// Value of smi in kSmiConstantRegister.
+static const int kSmiConstantRegisterValue = 1;
 
 // Convenience for platform-independent signatures.
 typedef Operand MemOperand;
 
 // Forward declaration.
 class JumpTarget;
 
 struct SmiIndex {
   SmiIndex(Register index_register, ScaleFactor scale)
       : reg(index_register),
@@ skipping 133 matching lines @@
   // the unresolved list if the name does not resolve.
   void InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag);
 
   // Store the code object for the given builtin in the target register.
   void GetBuiltinEntry(Register target, Builtins::JavaScript id);
 
 
   // ---------------------------------------------------------------------------
   // Smi tagging, untagging and operations on tagged smis.
 
+  void InitializeSmiConstantRegister() {
+    movq(kSmiConstantRegister,
+         reinterpret_cast<uint64_t>(Smi::FromInt(kSmiConstantRegisterValue)),
+         RelocInfo::NONE);
+  }
+
   // Conversions between tagged smi values and non-tagged integer values.
 
   // Tag an integer value. The result must be known to be a valid smi value.
   // Only uses the low 32 bits of the src register. Sets the N and Z flags
   // based on the value of the resulting integer.
   void Integer32ToSmi(Register dst, Register src);
 
   // Tag an integer value if possible, or jump the integer value cannot be
   // represented as a smi. Only uses the low 32 bit of the src registers.
   // NOTICE: Destroys the dst register even if unsuccessful!
@@ skipping 247 matching lines @@
   // The returned index register may be either src or dst, depending
   // on what is most efficient. If src and dst are different registers,
   // src is always unchanged.
   SmiIndex SmiToIndex(Register dst, Register src, int shift);
 
   // Converts a positive smi to a negative index.
   SmiIndex SmiToNegativeIndex(Register dst, Register src, int shift);
 
   // Basic Smi operations.
   void Move(Register dst, Smi* source) {
-    Set(dst, reinterpret_cast<int64_t>(source));
+    LoadSmiConstant(dst, source);
   }
 
   void Move(const Operand& dst, Smi* source) {
-    Set(dst, reinterpret_cast<int64_t>(source));
+    Register constant = GetSmiConstant(source);
+    movq(dst, constant);
   }
 
   void Push(Smi* smi);
   void Test(const Operand& dst, Smi* source);
 
   // ---------------------------------------------------------------------------
   // String macros.
   void JumpIfNotBothSequentialAsciiStrings(Register first_object,
                                            Register second_object,
                                            Register scratch1,
@@ skipping 326 matching lines @@
 
   // Verify restrictions about code generated in stubs.
   void set_generating_stub(bool value) { generating_stub_ = value; }
   bool generating_stub() { return generating_stub_; }
   void set_allow_stub_calls(bool value) { allow_stub_calls_ = value; }
   bool allow_stub_calls() { return allow_stub_calls_; }
 
  private:
   bool generating_stub_;
   bool allow_stub_calls_;
+
+  // Returns a register holding the smi value. The register MUST NOT be
+  // modified. It may be the "smi 1 constant" register.
+  Register GetSmiConstant(Smi* value);
+
+  // Moves the smi value to the destination register.
+  void LoadSmiConstant(Register dst, Smi* value);
+
   // This handle will be patched with the code object on installation.
   Handle<Object> code_object_;
 
   // Helper functions for generating invokes.
   void InvokePrologue(const ParameterCount& expected,
                       const ParameterCount& actual,
                       Handle<Code> code_constant,
                       Register code_register,
                       Label* done,
                       InvokeFlag flag);
@@ skipping 74 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_