Get rid of the unused native code StringAddStub.

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index c7010c9c23c08564deafaa633f361c9cfd254048..2953821cb96dcff1812040f061f0fa892085e807 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -351,7 +351,7 @@ void BinaryOpWithAllocationSiteStub::InitializeInterfaceDescriptor(
 }
 
 
-void NewStringAddStub::InitializeInterfaceDescriptor(
+void StringAddStub::InitializeInterfaceDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor) {
   static Register registers[] = { a1, a0 };
@@ -4561,355 +4561,6 @@ void BinaryOpICWithAllocationSiteStub::Generate(MacroAssembler* masm) {
 }
 
 
-void StringAddStub::Generate(MacroAssembler* masm) {
-  Label call_runtime, call_builtin;
-  Builtins::JavaScript builtin_id = Builtins::ADD;
-
-  Counters* counters = masm->isolate()->counters();
-
-  // Stack on entry:
-  // sp[0]: second argument (right).
-  // sp[4]: first argument (left).
-
-  // Load the two arguments.
-  __ lw(a0, MemOperand(sp, 1 * kPointerSize));  // First argument.
-  __ lw(a1, MemOperand(sp, 0 * kPointerSize));  // Second argument.
-
-  // Make sure that both arguments are strings if not known in advance.
-  // Otherwise, at least one of the arguments is definitely a string,
-  // and we convert the one that is not known to be a string.
-  if ((flags_ & STRING_ADD_CHECK_BOTH) == STRING_ADD_CHECK_BOTH) {
-    ASSERT((flags_ & STRING_ADD_CHECK_LEFT) == STRING_ADD_CHECK_LEFT);
-    ASSERT((flags_ & STRING_ADD_CHECK_RIGHT) == STRING_ADD_CHECK_RIGHT);
-    __ JumpIfEitherSmi(a0, a1, &call_runtime);
-    // Load instance types.
-    __ lw(t0, FieldMemOperand(a0, HeapObject::kMapOffset));
-    __ lw(t1, FieldMemOperand(a1, HeapObject::kMapOffset));
-    __ lbu(t0, FieldMemOperand(t0, Map::kInstanceTypeOffset));
-    __ lbu(t1, FieldMemOperand(t1, Map::kInstanceTypeOffset));
-    STATIC_ASSERT(kStringTag == 0);
-    // If either is not a string, go to runtime.
-    __ Or(t4, t0, Operand(t1));
-    __ And(t4, t4, Operand(kIsNotStringMask));
-    __ Branch(&call_runtime, ne, t4, Operand(zero_reg));
-  } else if ((flags_ & STRING_ADD_CHECK_LEFT) == STRING_ADD_CHECK_LEFT) {
-    ASSERT((flags_ & STRING_ADD_CHECK_RIGHT) == 0);
-    GenerateConvertArgument(
-        masm, 1 * kPointerSize, a0, a2, a3, t0, t1, &call_builtin);
-    builtin_id = Builtins::STRING_ADD_RIGHT;
-  } else if ((flags_ & STRING_ADD_CHECK_RIGHT) == STRING_ADD_CHECK_RIGHT) {
-    ASSERT((flags_ & STRING_ADD_CHECK_LEFT) == 0);
-    GenerateConvertArgument(
-        masm, 0 * kPointerSize, a1, a2, a3, t0, t1, &call_builtin);
-    builtin_id = Builtins::STRING_ADD_LEFT;
-  }
-
-  // Both arguments are strings.
-  // a0: first string
-  // a1: second string
-  // t0: first string instance type (if flags_ == NO_STRING_ADD_FLAGS)
-  // t1: second string instance type (if flags_ == NO_STRING_ADD_FLAGS)
-  {
-    Label strings_not_empty;
-    // Check if either of the strings are empty. In that case return the other.
-    // These tests use zero-length check on string-length whch is an Smi.
-    // Assert that Smi::FromInt(0) is really 0.
-    STATIC_ASSERT(kSmiTag == 0);
-    ASSERT(Smi::FromInt(0) == 0);
-    __ lw(a2, FieldMemOperand(a0, String::kLengthOffset));
-    __ lw(a3, FieldMemOperand(a1, String::kLengthOffset));
-    __ mov(v0, a0);       // Assume we'll return first string (from a0).
-    __ Movz(v0, a1, a2);  // If first is empty, return second (from a1).
-    __ slt(t4, zero_reg, a2);   // if (a2 > 0) t4 = 1.
-    __ slt(t5, zero_reg, a3);   // if (a3 > 0) t5 = 1.
-    __ and_(t4, t4, t5);        // Branch if both strings were non-empty.
-    __ Branch(&strings_not_empty, ne, t4, Operand(zero_reg));
-
-    __ IncrementCounter(counters->string_add_native(), 1, a2, a3);
-    __ DropAndRet(2);
-
-    __ bind(&strings_not_empty);
-  }
-
-  // Untag both string-lengths.
-  __ sra(a2, a2, kSmiTagSize);
-  __ sra(a3, a3, kSmiTagSize);
-
-  // Both strings are non-empty.
-  // a0: first string
-  // a1: second string
-  // a2: length of first string
-  // a3: length of second string
-  // t0: first string instance type (if flags_ == NO_STRING_ADD_FLAGS)
-  // t1: second string instance type (if flags_ == NO_STRING_ADD_FLAGS)
-  // Look at the length of the result of adding the two strings.
-  Label string_add_flat_result, longer_than_two;
-  // Adding two lengths can't overflow.
-  STATIC_ASSERT(String::kMaxLength < String::kMaxLength * 2);
-  __ Addu(t2, a2, Operand(a3));
-  // Use the string table when adding two one character strings, as it
-  // helps later optimizations to return a string here.
-  __ Branch(&longer_than_two, ne, t2, Operand(2));
-
-  // Check that both strings are non-external ASCII strings.
-  if ((flags_ & STRING_ADD_CHECK_BOTH) != STRING_ADD_CHECK_BOTH) {
-    __ lw(t0, FieldMemOperand(a0, HeapObject::kMapOffset));
-    __ lw(t1, FieldMemOperand(a1, HeapObject::kMapOffset));
-    __ lbu(t0, FieldMemOperand(t0, Map::kInstanceTypeOffset));
-    __ lbu(t1, FieldMemOperand(t1, Map::kInstanceTypeOffset));
-  }
-  __ JumpIfBothInstanceTypesAreNotSequentialAscii(t0, t1, t2, t3,
-                                                 &call_runtime);
-
-  // Get the two characters forming the sub string.
-  __ lbu(a2, FieldMemOperand(a0, SeqOneByteString::kHeaderSize));
-  __ lbu(a3, FieldMemOperand(a1, SeqOneByteString::kHeaderSize));
-
-  // Try to lookup two character string in string table. If it is not found
-  // just allocate a new one.
-  Label make_two_character_string;
-  StringHelper::GenerateTwoCharacterStringTableProbe(
-      masm, a2, a3, t2, t3, t0, t1, t5, &make_two_character_string);
-  __ IncrementCounter(counters->string_add_native(), 1, a2, a3);
-  __ DropAndRet(2);
-
-  __ bind(&make_two_character_string);
-  // Resulting string has length 2 and first chars of two strings
-  // are combined into single halfword in a2 register.
-  // So we can fill resulting string without two loops by a single
-  // halfword store instruction (which assumes that processor is
-  // in a little endian mode).
-  __ li(t2, Operand(2));
-  __ AllocateAsciiString(v0, t2, t0, t1, t5, &call_runtime);
-  __ sh(a2, FieldMemOperand(v0, SeqOneByteString::kHeaderSize));
-  __ IncrementCounter(counters->string_add_native(), 1, a2, a3);
-  __ DropAndRet(2);
-
-  __ bind(&longer_than_two);
-  // Check if resulting string will be flat.
-  __ Branch(&string_add_flat_result, lt, t2, Operand(ConsString::kMinLength));
-  // Handle exceptionally long strings in the runtime system.
-  STATIC_ASSERT((String::kMaxLength & 0x80000000) == 0);
-  ASSERT(IsPowerOf2(String::kMaxLength + 1));
-  // kMaxLength + 1 is representable as shifted literal, kMaxLength is not.
-  __ Branch(&call_runtime, hs, t2, Operand(String::kMaxLength + 1));
-
-  // If result is not supposed to be flat, allocate a cons string object.
-  // If both strings are ASCII the result is an ASCII cons string.
-  if ((flags_ & STRING_ADD_CHECK_BOTH) != STRING_ADD_CHECK_BOTH) {
-    __ lw(t0, FieldMemOperand(a0, HeapObject::kMapOffset));
-    __ lw(t1, FieldMemOperand(a1, HeapObject::kMapOffset));
-    __ lbu(t0, FieldMemOperand(t0, Map::kInstanceTypeOffset));
-    __ lbu(t1, FieldMemOperand(t1, Map::kInstanceTypeOffset));
-  }
-  Label non_ascii, allocated, ascii_data;
-  STATIC_ASSERT(kTwoByteStringTag == 0);
-  // Branch to non_ascii if either string-encoding field is zero (non-ASCII).
-  __ And(t4, t0, Operand(t1));
-  __ And(t4, t4, Operand(kStringEncodingMask));
-  __ Branch(&non_ascii, eq, t4, Operand(zero_reg));
-
-  // Allocate an ASCII cons string.
-  __ bind(&ascii_data);
-  __ AllocateAsciiConsString(v0, t2, t0, t1, &call_runtime);
-  __ bind(&allocated);
-  // Fill the fields of the cons string.
-  Label skip_write_barrier, after_writing;
-  ExternalReference high_promotion_mode = ExternalReference::
-      new_space_high_promotion_mode_active_address(masm->isolate());
-  __ li(t0, Operand(high_promotion_mode));
-  __ lw(t0, MemOperand(t0, 0));
-  __ Branch(&skip_write_barrier, eq, t0, Operand(zero_reg));
-
-  __ mov(t3, v0);
-  __ sw(a0, FieldMemOperand(t3, ConsString::kFirstOffset));
-  __ RecordWriteField(t3,
-                      ConsString::kFirstOffset,
-                      a0,
-                      t0,
-                      kRAHasNotBeenSaved,
-                      kDontSaveFPRegs);
-  __ sw(a1, FieldMemOperand(t3, ConsString::kSecondOffset));
-  __ RecordWriteField(t3,
-                      ConsString::kSecondOffset,
-                      a1,
-                      t0,
-                      kRAHasNotBeenSaved,
-                      kDontSaveFPRegs);
-  __ jmp(&after_writing);
-
-  __ bind(&skip_write_barrier);
-  __ sw(a0, FieldMemOperand(v0, ConsString::kFirstOffset));
-  __ sw(a1, FieldMemOperand(v0, ConsString::kSecondOffset));
-
-  __ bind(&after_writing);
-
-  __ IncrementCounter(counters->string_add_native(), 1, a2, a3);
-  __ DropAndRet(2);
-
-  __ bind(&non_ascii);
-  // At least one of the strings is two-byte. Check whether it happens
-  // to contain only one byte characters.
-  // t0: first instance type.
-  // t1: second instance type.
-  // Branch to if _both_ instances have kOneByteDataHintMask set.
-  __ And(at, t0, Operand(kOneByteDataHintMask));
-  __ and_(at, at, t1);
-  __ Branch(&ascii_data, ne, at, Operand(zero_reg));
-  __ Xor(t0, t0, Operand(t1));
-  STATIC_ASSERT(kOneByteStringTag != 0 && kOneByteDataHintTag != 0);
-  __ And(t0, t0, Operand(kOneByteStringTag | kOneByteDataHintTag));
-  __ Branch(&ascii_data, eq, t0,
-      Operand(kOneByteStringTag | kOneByteDataHintTag));
-
-  // Allocate a two byte cons string.
-  __ AllocateTwoByteConsString(v0, t2, t0, t1, &call_runtime);
-  __ Branch(&allocated);
-
-  // We cannot encounter sliced strings or cons strings here since:
-  STATIC_ASSERT(SlicedString::kMinLength >= ConsString::kMinLength);
-  // Handle creating a flat result from either external or sequential strings.
-  // Locate the first characters' locations.
-  // a0: first string
-  // a1: second string
-  // a2: length of first string
-  // a3: length of second string
-  // t0: first string instance type (if flags_ == NO_STRING_ADD_FLAGS)
-  // t1: second string instance type (if flags_ == NO_STRING_ADD_FLAGS)
-  // t2: sum of lengths.
-  Label first_prepared, second_prepared;
-  __ bind(&string_add_flat_result);
-  if ((flags_ & STRING_ADD_CHECK_BOTH) != STRING_ADD_CHECK_BOTH) {
-    __ lw(t0, FieldMemOperand(a0, HeapObject::kMapOffset));
-    __ lw(t1, FieldMemOperand(a1, HeapObject::kMapOffset));
-    __ lbu(t0, FieldMemOperand(t0, Map::kInstanceTypeOffset));
-    __ lbu(t1, FieldMemOperand(t1, Map::kInstanceTypeOffset));
-  }
-  // Check whether both strings have same encoding
-  __ Xor(t3, t0, Operand(t1));
-  __ And(t3, t3, Operand(kStringEncodingMask));
-  __ Branch(&call_runtime, ne, t3, Operand(zero_reg));
-
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ And(t4, t0, Operand(kStringRepresentationMask));
-
-  STATIC_ASSERT(SeqOneByteString::kHeaderSize == SeqTwoByteString::kHeaderSize);
-  Label skip_first_add;
-  __ Branch(&skip_first_add, ne, t4, Operand(zero_reg));
-  __ Branch(USE_DELAY_SLOT, &first_prepared);
-  __ addiu(t3, a0, SeqOneByteString::kHeaderSize - kHeapObjectTag);
-  __ bind(&skip_first_add);
-  // External string: rule out short external string and load string resource.
-  STATIC_ASSERT(kShortExternalStringTag != 0);
-  __ And(t4, t0, Operand(kShortExternalStringMask));
-  __ Branch(&call_runtime, ne, t4, Operand(zero_reg));
-  __ lw(t3, FieldMemOperand(a0, ExternalString::kResourceDataOffset));
-  __ bind(&first_prepared);
-
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ And(t4, t1, Operand(kStringRepresentationMask));
-  STATIC_ASSERT(SeqOneByteString::kHeaderSize == SeqTwoByteString::kHeaderSize);
-  Label skip_second_add;
-  __ Branch(&skip_second_add, ne, t4, Operand(zero_reg));
-  __ Branch(USE_DELAY_SLOT, &second_prepared);
-  __ addiu(a1, a1, SeqOneByteString::kHeaderSize - kHeapObjectTag);
-  __ bind(&skip_second_add);
-  // External string: rule out short external string and load string resource.
-  STATIC_ASSERT(kShortExternalStringTag != 0);
-  __ And(t4, t1, Operand(kShortExternalStringMask));
-  __ Branch(&call_runtime, ne, t4, Operand(zero_reg));
-  __ lw(a1, FieldMemOperand(a1, ExternalString::kResourceDataOffset));
-  __ bind(&second_prepared);
-
-  Label non_ascii_string_add_flat_result;
-  // t3: first character of first string
-  // a1: first character of second string
-  // a2: length of first string
-  // a3: length of second string
-  // t2: sum of lengths.
-  // Both strings have the same encoding.
-  STATIC_ASSERT(kTwoByteStringTag == 0);
-  __ And(t4, t1, Operand(kStringEncodingMask));
-  __ Branch(&non_ascii_string_add_flat_result, eq, t4, Operand(zero_reg));
-
-  __ AllocateAsciiString(v0, t2, t0, t1, t5, &call_runtime);
-  __ Addu(t2, v0, Operand(SeqOneByteString::kHeaderSize - kHeapObjectTag));
-  // v0: result string.
-  // t3: first character of first string.
-  // a1: first character of second string
-  // a2: length of first string.
-  // a3: length of second string.
-  // t2: first character of result.
-
-  StringHelper::GenerateCopyCharacters(masm, t2, t3, a2, t0, true);
-  // t2: next character of result.
-  StringHelper::GenerateCopyCharacters(masm, t2, a1, a3, t0, true);
-  __ IncrementCounter(counters->string_add_native(), 1, a2, a3);
-  __ DropAndRet(2);
-
-  __ bind(&non_ascii_string_add_flat_result);
-  __ AllocateTwoByteString(v0, t2, t0, t1, t5, &call_runtime);
-  __ Addu(t2, v0, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  // v0: result string.
-  // t3: first character of first string.
-  // a1: first character of second string.
-  // a2: length of first string.
-  // a3: length of second string.
-  // t2: first character of result.
-  StringHelper::GenerateCopyCharacters(masm, t2, t3, a2, t0, false);
-  // t2: next character of result.
-  StringHelper::GenerateCopyCharacters(masm, t2, a1, a3, t0, false);
-
-  __ IncrementCounter(counters->string_add_native(), 1, a2, a3);
-  __ DropAndRet(2);
-
-  // Just jump to runtime to add the two strings.
-  __ bind(&call_runtime);
-  __ TailCallRuntime(Runtime::kStringAdd, 2, 1);
-
-  if (call_builtin.is_linked()) {
-    __ bind(&call_builtin);
-    __ InvokeBuiltin(builtin_id, JUMP_FUNCTION);
-  }
-}
-
-
-void StringAddStub::GenerateRegisterArgsPush(MacroAssembler* masm) {
-  __ push(a0);
-  __ push(a1);
-}
-
-
-void StringAddStub::GenerateRegisterArgsPop(MacroAssembler* masm) {
-  __ pop(a1);
-  __ pop(a0);
-}
-
-
-void StringAddStub::GenerateConvertArgument(MacroAssembler* masm,
-                                            int stack_offset,
-                                            Register arg,
-                                            Register scratch1,
-                                            Register scratch2,
-                                            Register scratch3,
-                                            Register scratch4,
-                                            Label* slow) {
-  // First check if the argument is already a string.
-  Label not_string, done;
-  __ JumpIfSmi(arg, &not_string);
-  __ GetObjectType(arg, scratch1, scratch1);
-  __ Branch(&done, lt, scratch1, Operand(FIRST_NONSTRING_TYPE));
-
-  // Check the number to string cache.
-  __ bind(&not_string);
-  // Puts the cached result into scratch1.
-  __ LookupNumberStringCache(arg, scratch1, scratch2, scratch3, scratch4, slow);
-  __ mov(arg, scratch1);
-  __ sw(arg, MemOperand(sp, stack_offset));
-  __ bind(&done);
-}
-
-
 void ICCompareStub::GenerateSmis(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::SMI);
   Label miss;