[stubs] Port SubStringStub to TurboFan

src/x64/code-stubs-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 1993 matching lines @@
   __ movb(kScratchRegister, Operand(src, 0));
   __ movb(Operand(dest, 0), kScratchRegister);
   __ incp(src);
   __ incp(dest);
   __ decl(count);
   __ j(not_zero, &loop);
 
   __ bind(&done);
 }
 
-
-void SubStringStub::Generate(MacroAssembler* masm) {
-  Label runtime;
-
-  // Stack frame on entry.
-  //  rsp[0]  : return address
-  //  rsp[8]  : to
-  //  rsp[16] : from
-  //  rsp[24] : string
-
-  enum SubStringStubArgumentIndices {
-    STRING_ARGUMENT_INDEX,
-    FROM_ARGUMENT_INDEX,
-    TO_ARGUMENT_INDEX,
-    SUB_STRING_ARGUMENT_COUNT
-  };
-
-  StackArgumentsAccessor args(rsp, SUB_STRING_ARGUMENT_COUNT,
-                              ARGUMENTS_DONT_CONTAIN_RECEIVER);
-
-  // Make sure first argument is a string.
-  __ movp(rax, args.GetArgumentOperand(STRING_ARGUMENT_INDEX));
-  STATIC_ASSERT(kSmiTag == 0);
-  __ testl(rax, Immediate(kSmiTagMask));
-  __ j(zero, &runtime);
-  Condition is_string = masm->IsObjectStringType(rax, rbx, rbx);
-  __ j(NegateCondition(is_string), &runtime);
-
-  // rax: string
-  // rbx: instance type
-  // Calculate length of sub string using the smi values.
-  __ movp(rcx, args.GetArgumentOperand(TO_ARGUMENT_INDEX));
-  __ movp(rdx, args.GetArgumentOperand(FROM_ARGUMENT_INDEX));
-  __ JumpUnlessBothNonNegativeSmi(rcx, rdx, &runtime);
-
-  __ SmiSub(rcx, rcx, rdx);  // Overflow doesn't happen.
-  __ cmpp(rcx, FieldOperand(rax, String::kLengthOffset));
-  Label not_original_string;
-  // Shorter than original string's length: an actual substring.
-  __ j(below, &not_original_string, Label::kNear);
-  // Longer than original string's length or negative: unsafe arguments.
-  __ j(above, &runtime);
-  // Return original string.
-  Counters* counters = isolate()->counters();
-  __ IncrementCounter(counters->sub_string_native(), 1);
-  __ ret(SUB_STRING_ARGUMENT_COUNT * kPointerSize);
-  __ bind(&not_original_string);
-
-  Label single_char;
-  __ SmiCompare(rcx, Smi::FromInt(1));
-  __ j(equal, &single_char);
-
-  __ SmiToInteger32(rcx, rcx);
-
-  // rax: string
-  // rbx: instance type
-  // rcx: sub string length
-  // rdx: from index (smi)
-  // Deal with different string types: update the index if necessary
-  // and put the underlying string into edi.
-  Label underlying_unpacked, sliced_string, seq_or_external_string;
-  // If the string is not indirect, it can only be sequential or external.
-  STATIC_ASSERT(kIsIndirectStringMask == (kSlicedStringTag & kConsStringTag));
-  STATIC_ASSERT(kIsIndirectStringMask != 0);
-  __ testb(rbx, Immediate(kIsIndirectStringMask));
-  __ j(zero, &seq_or_external_string, Label::kNear);
-
-  __ testb(rbx, Immediate(kSlicedNotConsMask));
-  __ j(not_zero, &sliced_string, Label::kNear);
-  // Cons string.  Check whether it is flat, then fetch first part.
-  // Flat cons strings have an empty second part.
-  __ CompareRoot(FieldOperand(rax, ConsString::kSecondOffset),
-                 Heap::kempty_stringRootIndex);
-  __ j(not_equal, &runtime);
-  __ movp(rdi, FieldOperand(rax, ConsString::kFirstOffset));
-  // Update instance type.
-  __ movp(rbx, FieldOperand(rdi, HeapObject::kMapOffset));
-  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
-  __ jmp(&underlying_unpacked, Label::kNear);
-
-  __ bind(&sliced_string);
-  // Sliced string.  Fetch parent and correct start index by offset.
-  __ addp(rdx, FieldOperand(rax, SlicedString::kOffsetOffset));
-  __ movp(rdi, FieldOperand(rax, SlicedString::kParentOffset));
-  // Update instance type.
-  __ movp(rbx, FieldOperand(rdi, HeapObject::kMapOffset));
-  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
-  __ jmp(&underlying_unpacked, Label::kNear);
-
-  __ bind(&seq_or_external_string);
-  // Sequential or external string.  Just move string to the correct register.
-  __ movp(rdi, rax);
-
-  __ bind(&underlying_unpacked);
-
-  if (FLAG_string_slices) {
-    Label copy_routine;
-    // rdi: underlying subject string
-    // rbx: instance type of underlying subject string
-    // rdx: adjusted start index (smi)
-    // rcx: length
-    // If coming from the make_two_character_string path, the string
-    // is too short to be sliced anyways.
-    __ cmpp(rcx, Immediate(SlicedString::kMinLength));
-    // Short slice.  Copy instead of slicing.
-    __ j(less, &copy_routine);
-    // Allocate new sliced string.  At this point we do not reload the instance
-    // type including the string encoding because we simply rely on the info
-    // provided by the original string.  It does not matter if the original
-    // string's encoding is wrong because we always have to recheck encoding of
-    // the newly created string's parent anyways due to externalized strings.
-    Label two_byte_slice, set_slice_header;
-    STATIC_ASSERT((kStringEncodingMask & kOneByteStringTag) != 0);
-    STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
-    __ testb(rbx, Immediate(kStringEncodingMask));
-    __ j(zero, &two_byte_slice, Label::kNear);
-    __ AllocateOneByteSlicedString(rax, rbx, r14, &runtime);
-    __ jmp(&set_slice_header, Label::kNear);
-    __ bind(&two_byte_slice);
-    __ AllocateTwoByteSlicedString(rax, rbx, r14, &runtime);
-    __ bind(&set_slice_header);
-    __ Integer32ToSmi(rcx, rcx);
-    __ movp(FieldOperand(rax, SlicedString::kLengthOffset), rcx);
-    __ movp(FieldOperand(rax, SlicedString::kHashFieldOffset),
-           Immediate(String::kEmptyHashField));
-    __ movp(FieldOperand(rax, SlicedString::kParentOffset), rdi);
-    __ movp(FieldOperand(rax, SlicedString::kOffsetOffset), rdx);
-    __ IncrementCounter(counters->sub_string_native(), 1);
-    __ ret(3 * kPointerSize);
-
-    __ bind(&copy_routine);
-  }
-
-  // rdi: underlying subject string
-  // rbx: instance type of underlying subject string
-  // rdx: adjusted start index (smi)
-  // rcx: length
-  // The subject string can only be external or sequential string of either
-  // encoding at this point.
-  Label two_byte_sequential, sequential_string;
-  STATIC_ASSERT(kExternalStringTag != 0);
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ testb(rbx, Immediate(kExternalStringTag));
-  __ j(zero, &sequential_string);
-
-  // Handle external string.
-  // Rule out short external strings.
-  STATIC_ASSERT(kShortExternalStringTag != 0);
-  __ testb(rbx, Immediate(kShortExternalStringMask));
-  __ j(not_zero, &runtime);
-  __ movp(rdi, FieldOperand(rdi, ExternalString::kResourceDataOffset));
-  // Move the pointer so that offset-wise, it looks like a sequential string.
-  STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
-  __ subp(rdi, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-
-  __ bind(&sequential_string);
-  STATIC_ASSERT((kOneByteStringTag & kStringEncodingMask) != 0);
-  __ testb(rbx, Immediate(kStringEncodingMask));
-  __ j(zero, &two_byte_sequential);
-
-  // Allocate the result.
-  __ AllocateOneByteString(rax, rcx, r11, r14, r15, &runtime);
-
-  // rax: result string
-  // rcx: result string length
-  {  // Locate character of sub string start.
-    SmiIndex smi_as_index = masm->SmiToIndex(rdx, rdx, times_1);
-    __ leap(r14, Operand(rdi, smi_as_index.reg, smi_as_index.scale,
-                        SeqOneByteString::kHeaderSize - kHeapObjectTag));
-  }
-  // Locate first character of result.
-  __ leap(rdi, FieldOperand(rax, SeqOneByteString::kHeaderSize));
-
-  // rax: result string
-  // rcx: result length
-  // r14: first character of result
-  // rsi: character of sub string start
-  StringHelper::GenerateCopyCharacters(
-      masm, rdi, r14, rcx, String::ONE_BYTE_ENCODING);
-  __ IncrementCounter(counters->sub_string_native(), 1);
-  __ ret(SUB_STRING_ARGUMENT_COUNT * kPointerSize);
-
-  __ bind(&two_byte_sequential);
-  // Allocate the result.
-  __ AllocateTwoByteString(rax, rcx, r11, r14, r15, &runtime);
-
-  // rax: result string
-  // rcx: result string length
-  {  // Locate character of sub string start.
-    SmiIndex smi_as_index = masm->SmiToIndex(rdx, rdx, times_2);
-    __ leap(r14, Operand(rdi, smi_as_index.reg, smi_as_index.scale,
-                        SeqOneByteString::kHeaderSize - kHeapObjectTag));
-  }
-  // Locate first character of result.
-  __ leap(rdi, FieldOperand(rax, SeqTwoByteString::kHeaderSize));
-
-  // rax: result string
-  // rcx: result length
-  // rdi: first character of result
-  // r14: character of sub string start
-  StringHelper::GenerateCopyCharacters(
-      masm, rdi, r14, rcx, String::TWO_BYTE_ENCODING);
-  __ IncrementCounter(counters->sub_string_native(), 1);
-  __ ret(SUB_STRING_ARGUMENT_COUNT * kPointerSize);
-
-  // Just jump to runtime to create the sub string.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kSubString);
-
-  __ bind(&single_char);
-  // rax: string
-  // rbx: instance type
-  // rcx: sub string length (smi)
-  // rdx: from index (smi)
-  StringCharAtGenerator generator(rax, rdx, rcx, rax, &runtime, &runtime,
-                                  &runtime, RECEIVER_IS_STRING);
-  generator.GenerateFast(masm);
-  __ ret(SUB_STRING_ARGUMENT_COUNT * kPointerSize);
-  generator.SkipSlow(masm, &runtime);
-}
-
 void ToStringStub::Generate(MacroAssembler* masm) {
   // The ToString stub takes one argument in rax.
   Label is_number;
   __ JumpIfSmi(rax, &is_number, Label::kNear);
 
   Label not_string;
   __ CmpObjectType(rax, FIRST_NONSTRING_TYPE, rdi);
   // rax: receiver
   // rdi: receiver map
   __ j(above_equal, &not_string, Label::kNear);
@@ skipping 2905 matching lines @@
                            kStackUnwindSpace, nullptr, return_value_operand,
                            NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64