[fullcodegen] Remove the hacky %_FastOneByteArrayJoin intrinsic.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 6b99d730c8e32a3bc6df415b1b863a9d33eeff5c..69ca48ff0cbe05739a9218bd48335ca21e49803f 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -3309,296 +3309,6 @@ void FullCodeGenerator::EmitGetSuperConstructor(CallRuntime* expr) {
 }
 
 
-void FullCodeGenerator::EmitFastOneByteArrayJoin(CallRuntime* expr) {
-  Label bailout, return_result, done, one_char_separator, long_separator,
-      non_trivial_array, not_size_one_array, loop,
-      loop_1, loop_1_condition, loop_2, loop_2_entry, loop_3, loop_3_entry;
-  ZoneList<Expression*>* args = expr->arguments();
-  DCHECK(args->length() == 2);
-  // We will leave the separator on the stack until the end of the function.
-  VisitForStackValue(args->at(1));
-  // Load this to rax (= array)
-  VisitForAccumulatorValue(args->at(0));
-  // All aliases of the same register have disjoint lifetimes.
-  Register array = rax;
-  Register elements = no_reg;  // Will be rax.
-
-  Register index = rdx;
-
-  Register string_length = rcx;
-
-  Register string = rsi;
-
-  Register scratch = rbx;
-
-  Register array_length = rdi;
-  Register result_pos = no_reg;  // Will be rdi.
-
-  Operand separator_operand =    Operand(rsp, 2 * kPointerSize);
-  Operand result_operand =       Operand(rsp, 1 * kPointerSize);
-  Operand array_length_operand = Operand(rsp, 0 * kPointerSize);
-  // Separator operand is already pushed. Make room for the two
-  // other stack fields, and clear the direction flag in anticipation
-  // of calling CopyBytes.
-  __ subp(rsp, Immediate(2 * kPointerSize));
-  __ cld();
-  // Check that the array is a JSArray
-  __ JumpIfSmi(array, &bailout);
-  __ CmpObjectType(array, JS_ARRAY_TYPE, scratch);
-  __ j(not_equal, &bailout);
-
-  // Check that the array has fast elements.
-  __ CheckFastElements(scratch, &bailout);
-
-  // Array has fast elements, so its length must be a smi.
-  // If the array has length zero, return the empty string.
-  __ movp(array_length, FieldOperand(array, JSArray::kLengthOffset));
-  __ SmiCompare(array_length, Smi::FromInt(0));
-  __ j(not_zero, &non_trivial_array);
-  __ LoadRoot(rax, Heap::kempty_stringRootIndex);
-  __ jmp(&return_result);
-
-  // Save the array length on the stack.
-  __ bind(&non_trivial_array);
-  __ SmiToInteger32(array_length, array_length);
-  __ movl(array_length_operand, array_length);
-
-  // Save the FixedArray containing array's elements.
-  // End of array's live range.
-  elements = array;
-  __ movp(elements, FieldOperand(array, JSArray::kElementsOffset));
-  array = no_reg;
-
-
-  // Check that all array elements are sequential one-byte strings, and
-  // accumulate the sum of their lengths, as a smi-encoded value.
-  __ Set(index, 0);
-  __ Set(string_length, 0);
-  // Loop condition: while (index < array_length).
-  // Live loop registers: index(int32), array_length(int32), string(String*),
-  //                      scratch, string_length(int32), elements(FixedArray*).
-  if (generate_debug_code_) {
-    __ cmpp(index, array_length);
-    __ Assert(below, kNoEmptyArraysHereInEmitFastOneByteArrayJoin);
-  }
-  __ bind(&loop);
-  __ movp(string, FieldOperand(elements,
-                               index,
-                               times_pointer_size,
-                               FixedArray::kHeaderSize));
-  __ JumpIfSmi(string, &bailout);
-  __ movp(scratch, FieldOperand(string, HeapObject::kMapOffset));
-  __ movzxbl(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
-  __ andb(scratch, Immediate(
-      kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
-  __ cmpb(scratch, Immediate(kStringTag | kOneByteStringTag | kSeqStringTag));
-  __ j(not_equal, &bailout);
-  __ AddSmiField(string_length,
-                 FieldOperand(string, SeqOneByteString::kLengthOffset));
-  __ j(overflow, &bailout);
-  __ incl(index);
-  __ cmpl(index, array_length);
-  __ j(less, &loop);
-
-  // Live registers:
-  // string_length: Sum of string lengths.
-  // elements: FixedArray of strings.
-  // index: Array length.
-  // array_length: Array length.
-
-  // If array_length is 1, return elements[0], a string.
-  __ cmpl(array_length, Immediate(1));
-  __ j(not_equal, &not_size_one_array);
-  __ movp(rax, FieldOperand(elements, FixedArray::kHeaderSize));
-  __ jmp(&return_result);
-
-  __ bind(&not_size_one_array);
-
-  // End of array_length live range.
-  result_pos = array_length;
-  array_length = no_reg;
-
-  // Live registers:
-  // string_length: Sum of string lengths.
-  // elements: FixedArray of strings.
-  // index: Array length.
-
-  // Check that the separator is a sequential one-byte string.
-  __ movp(string, separator_operand);
-  __ JumpIfSmi(string, &bailout);
-  __ movp(scratch, FieldOperand(string, HeapObject::kMapOffset));
-  __ movzxbl(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
-  __ andb(scratch, Immediate(
-      kIsNotStringMask | kStringEncodingMask | kStringRepresentationMask));
-  __ cmpb(scratch, Immediate(kStringTag | kOneByteStringTag | kSeqStringTag));
-  __ j(not_equal, &bailout);
-
-  // Live registers:
-  // string_length: Sum of string lengths.
-  // elements: FixedArray of strings.
-  // index: Array length.
-  // string: Separator string.
-
-  // Add (separator length times (array_length - 1)) to string_length.
-  __ SmiToInteger32(scratch,
-                    FieldOperand(string, SeqOneByteString::kLengthOffset));
-  __ decl(index);
-  __ imull(scratch, index);
-  __ j(overflow, &bailout);
-  __ addl(string_length, scratch);
-  __ j(overflow, &bailout);
-  __ jmp(&bailout);
-
-  // Bailout for large object allocations.
-  __ cmpl(string_length, Immediate(Page::kMaxRegularHeapObjectSize));
-  __ j(greater, &bailout);
-
-  // Live registers and stack values:
-  //   string_length: Total length of result string.
-  //   elements: FixedArray of strings.
-  __ AllocateOneByteString(result_pos, string_length, scratch, index, string,
-                           &bailout);
-  __ movp(result_operand, result_pos);
-  __ leap(result_pos, FieldOperand(result_pos, SeqOneByteString::kHeaderSize));
-
-  __ movp(string, separator_operand);
-  __ SmiCompare(FieldOperand(string, SeqOneByteString::kLengthOffset),
-                Smi::FromInt(1));
-  __ j(equal, &one_char_separator);
-  __ j(greater, &long_separator);
-
-
-  // Empty separator case:
-  __ Set(index, 0);
-  __ movl(scratch, array_length_operand);
-  __ jmp(&loop_1_condition);
-  // Loop condition: while (index < array_length).
-  __ bind(&loop_1);
-  // Each iteration of the loop concatenates one string to the result.
-  // Live values in registers:
-  //   index: which element of the elements array we are adding to the result.
-  //   result_pos: the position to which we are currently copying characters.
-  //   elements: the FixedArray of strings we are joining.
-  //   scratch: array length.
-
-  // Get string = array[index].
-  __ movp(string, FieldOperand(elements, index,
-                               times_pointer_size,
-                               FixedArray::kHeaderSize));
-  __ SmiToInteger32(string_length,
-                    FieldOperand(string, String::kLengthOffset));
-  __ leap(string,
-         FieldOperand(string, SeqOneByteString::kHeaderSize));
-  __ CopyBytes(result_pos, string, string_length);
-  __ incl(index);
-  __ bind(&loop_1_condition);
-  __ cmpl(index, scratch);
-  __ j(less, &loop_1);  // Loop while (index < array_length).
-  __ jmp(&done);
-
-  // Generic bailout code used from several places.
-  __ bind(&bailout);
-  __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
-  __ jmp(&return_result);
-
-
-  // One-character separator case
-  __ bind(&one_char_separator);
-  // Get the separator one-byte character value.
-  // Register "string" holds the separator.
-  __ movzxbl(scratch, FieldOperand(string, SeqOneByteString::kHeaderSize));
-  __ Set(index, 0);
-  // Jump into the loop after the code that copies the separator, so the first
-  // element is not preceded by a separator
-  __ jmp(&loop_2_entry);
-  // Loop condition: while (index < length).
-  __ bind(&loop_2);
-  // Each iteration of the loop concatenates one string to the result.
-  // Live values in registers:
-  //   elements: The FixedArray of strings we are joining.
-  //   index: which element of the elements array we are adding to the result.
-  //   result_pos: the position to which we are currently copying characters.
-  //   scratch: Separator character.
-
-  // Copy the separator character to the result.
-  __ movb(Operand(result_pos, 0), scratch);
-  __ incp(result_pos);
-
-  __ bind(&loop_2_entry);
-  // Get string = array[index].
-  __ movp(string, FieldOperand(elements, index,
-                               times_pointer_size,
-                               FixedArray::kHeaderSize));
-  __ SmiToInteger32(string_length,
-                    FieldOperand(string, String::kLengthOffset));
-  __ leap(string,
-         FieldOperand(string, SeqOneByteString::kHeaderSize));
-  __ CopyBytes(result_pos, string, string_length);
-  __ incl(index);
-  __ cmpl(index, array_length_operand);
-  __ j(less, &loop_2);  // End while (index < length).
-  __ jmp(&done);
-
-
-  // Long separator case (separator is more than one character).
-  __ bind(&long_separator);
-
-  // Make elements point to end of elements array, and index
-  // count from -array_length to zero, so we don't need to maintain
-  // a loop limit.
-  __ movl(index, array_length_operand);
-  __ leap(elements, FieldOperand(elements, index, times_pointer_size,
-                                FixedArray::kHeaderSize));
-  __ negq(index);
-
-  // Replace separator string with pointer to its first character, and
-  // make scratch be its length.
-  __ movp(string, separator_operand);
-  __ SmiToInteger32(scratch,
-                    FieldOperand(string, String::kLengthOffset));
-  __ leap(string,
-         FieldOperand(string, SeqOneByteString::kHeaderSize));
-  __ movp(separator_operand, string);
-
-  // Jump into the loop after the code that copies the separator, so the first
-  // element is not preceded by a separator
-  __ jmp(&loop_3_entry);
-  // Loop condition: while (index < length).
-  __ bind(&loop_3);
-  // Each iteration of the loop concatenates one string to the result.
-  // Live values in registers:
-  //   index: which element of the elements array we are adding to the result.
-  //   result_pos: the position to which we are currently copying characters.
-  //   scratch: Separator length.
-  //   separator_operand (rsp[0x10]): Address of first char of separator.
-
-  // Copy the separator to the result.
-  __ movp(string, separator_operand);
-  __ movl(string_length, scratch);
-  __ CopyBytes(result_pos, string, string_length, 2);
-
-  __ bind(&loop_3_entry);
-  // Get string = array[index].
-  __ movp(string, Operand(elements, index, times_pointer_size, 0));
-  __ SmiToInteger32(string_length,
-                    FieldOperand(string, String::kLengthOffset));
-  __ leap(string,
-         FieldOperand(string, SeqOneByteString::kHeaderSize));
-  __ CopyBytes(result_pos, string, string_length);
-  __ incq(index);
-  __ j(not_equal, &loop_3);  // Loop while (index < 0).
-
-  __ bind(&done);
-  __ movp(rax, result_operand);
-
-  __ bind(&return_result);
-  // Drop temp values from the stack, and restore context register.
-  __ addp(rsp, Immediate(3 * kPointerSize));
-  __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
-  context()->Plug(rax);
-}
-
-
 void FullCodeGenerator::EmitDebugIsActive(CallRuntime* expr) {
   DCHECK(expr->arguments()->length() == 0);
   ExternalReference debug_is_active =