Perform string add in generated code on X64 platform...

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
===================================================================
--- src/x64/macro-assembler-x64.cc	(revision 3430)
+++ src/x64/macro-assembler-x64.cc	(working copy)
@@ -310,6 +310,12 @@
 }
 
 
+void MacroAssembler::TailCallStub(CodeStub* stub) {
+  ASSERT(allow_stub_calls());  // calls are not allowed in some stubs
+  Jump(stub->GetCode(), RelocInfo::CODE_TARGET);
+}
+
+
 void MacroAssembler::StubReturn(int argc) {
   ASSERT(argc >= 1 && generating_stub());
   ret((argc - 1) * kPointerSize);
@@ -2244,6 +2250,108 @@
 }
 
 
+void MacroAssembler::AllocateTwoByteString(Register result,
+                                           Register length,
+                                           Register scratch1,
+                                           Register scratch2,
+                                           Register scratch3,
+                                           Label* gc_required) {
+  // Calculate the number of bytes needed for the characters in the string while
+  // observing object alignment.
+  ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
+  ASSERT(kShortSize == 2);
+  // scratch1 = length * 2 + kObjectAlignmentMask.
+  lea(scratch1, Operand(length, length, times_1, kObjectAlignmentMask));
+  and_(scratch1, Immediate(~kObjectAlignmentMask));
+
+  // Allocate two byte string in new space.
+  AllocateInNewSpace(SeqTwoByteString::kHeaderSize,
+                     times_1,
+                     scratch1,
+                     result,
+                     scratch2,
+                     scratch3,
+                     gc_required,
+                     TAG_OBJECT);
+
+  // Set the map, length and hash field.
+  LoadRoot(kScratchRegister, Heap::kStringMapRootIndex);
+  movq(FieldOperand(result, HeapObject::kMapOffset), kScratchRegister);
+  movl(FieldOperand(result, String::kLengthOffset), length);
+  movl(FieldOperand(result, String::kHashFieldOffset),
+       Immediate(String::kEmptyHashField));
+}
+
+
+void MacroAssembler::AllocateAsciiString(Register result,
+                                         Register length,
+                                         Register scratch1,
+                                         Register scratch2,
+                                         Register scratch3,
+                                         Label* gc_required) {
+  // Calculate the number of bytes needed for the characters in the string while
+  // observing object alignment.
+  ASSERT((SeqAsciiString::kHeaderSize & kObjectAlignmentMask) == 0);
+  movl(scratch1, length);
+  ASSERT(kCharSize == 1);
+  addq(scratch1, Immediate(kObjectAlignmentMask));
+  and_(scratch1, Immediate(~kObjectAlignmentMask));
+
+  // Allocate ascii string in new space.
+  AllocateInNewSpace(SeqAsciiString::kHeaderSize,
+                     times_1,
+                     scratch1,
+                     result,
+                     scratch2,
+                     scratch3,
+                     gc_required,
+                     TAG_OBJECT);
+
+  // Set the map, length and hash field.
+  LoadRoot(kScratchRegister, Heap::kAsciiStringMapRootIndex);
+  movq(FieldOperand(result, HeapObject::kMapOffset), kScratchRegister);
+  movl(FieldOperand(result, String::kLengthOffset), length);
+  movl(FieldOperand(result, String::kHashFieldOffset),
+       Immediate(String::kEmptyHashField));
+}
+
+
+void MacroAssembler::AllocateConsString(Register result,
+                                        Register scratch1,
+                                        Register scratch2,
+                                        Label* gc_required) {
+  // Allocate heap number in new space.
+  AllocateInNewSpace(ConsString::kSize,
+                     result,
+                     scratch1,
+                     scratch2,
+                     gc_required,
+                     TAG_OBJECT);
+
+  // Set the map. The other fields are left uninitialized.
+  LoadRoot(kScratchRegister, Heap::kConsStringMapRootIndex);
+  movq(FieldOperand(result, HeapObject::kMapOffset), kScratchRegister);
+}
+
+
+void MacroAssembler::AllocateAsciiConsString(Register result,
+                                             Register scratch1,
+                                             Register scratch2,
+                                             Label* gc_required) {
+  // Allocate heap number in new space.
+  AllocateInNewSpace(ConsString::kSize,
+                     result,
+                     scratch1,
+                     scratch2,
+                     gc_required,
+                     TAG_OBJECT);
+
+  // Set the map. The other fields are left uninitialized.
+  LoadRoot(kScratchRegister, Heap::kConsAsciiStringMapRootIndex);
+  movq(FieldOperand(result, HeapObject::kMapOffset), kScratchRegister);
+}
+
+
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.