[stubs] Port SubStringStub to TurboFan

src/s390/code-stubs-s390.cc

 // Copyright 2014 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_S390
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 2184 matching lines @@
   __ bind(&byte_loop);
   __ LoadlB(scratch, MemOperand(src));
   __ la(src, MemOperand(src, 1));
   __ stc(scratch, MemOperand(dest));
   __ la(dest, MemOperand(dest, 1));
   __ BranchOnCount(count, &byte_loop);
 
   __ bind(&done);
 }
 
-void SubStringStub::Generate(MacroAssembler* masm) {
-  Label runtime;
-
-  // Stack frame on entry.
-  //  lr: return address
-  //  sp[0]: to
-  //  sp[4]: from
-  //  sp[8]: string
-
-  // This stub is called from the native-call %_SubString(...), so
-  // nothing can be assumed about the arguments. It is tested that:
-  //  "string" is a sequential string,
-  //  both "from" and "to" are smis, and
-  //  0 <= from <= to <= string.length.
-  // If any of these assumptions fail, we call the runtime system.
-
-  const int kToOffset = 0 * kPointerSize;
-  const int kFromOffset = 1 * kPointerSize;
-  const int kStringOffset = 2 * kPointerSize;
-
-  __ LoadP(r4, MemOperand(sp, kToOffset));
-  __ LoadP(r5, MemOperand(sp, kFromOffset));
-
-  // If either to or from had the smi tag bit set, then fail to generic runtime
-  __ JumpIfNotSmi(r4, &runtime);
-  __ JumpIfNotSmi(r5, &runtime);
-  __ SmiUntag(r4);
-  __ SmiUntag(r5);
-  // Both r4 and r5 are untagged integers.
-
-  // We want to bailout to runtime here if From is negative.
-  __ blt(&runtime);  // From < 0.
-
-  __ CmpLogicalP(r5, r4);
-  __ bgt(&runtime);  // Fail if from > to.
-  __ SubP(r4, r4, r5);
-
-  // Make sure first argument is a string.
-  __ LoadP(r2, MemOperand(sp, kStringOffset));
-  __ JumpIfSmi(r2, &runtime);
-  Condition is_string = masm->IsObjectStringType(r2, r3);
-  __ b(NegateCondition(is_string), &runtime);
-
-  Label single_char;
-  __ CmpP(r4, Operand(1));
-  __ b(eq, &single_char);
-
-  // Short-cut for the case of trivial substring.
-  Label return_r2;
-  // r2: original string
-  // r4: result string length
-  __ LoadP(r6, FieldMemOperand(r2, String::kLengthOffset));
-  __ SmiUntag(r0, r6);
-  __ CmpLogicalP(r4, r0);
-  // Return original string.
-  __ beq(&return_r2);
-  // Longer than original string's length or negative: unsafe arguments.
-  __ bgt(&runtime);
-  // Shorter than original string's length: an actual substring.
-
-  // Deal with different string types: update the index if necessary
-  // and put the underlying string into r7.
-  // r2: original string
-  // r3: instance type
-  // r4: length
-  // r5: from index (untagged)
-  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);
-  __ mov(r0, Operand(kIsIndirectStringMask));
-  __ AndP(r0, r3);
-  __ beq(&seq_or_external_string);
-
-  __ mov(r0, Operand(kSlicedNotConsMask));
-  __ AndP(r0, r3);
-  __ bne(&sliced_string);
-  // Cons string.  Check whether it is flat, then fetch first part.
-  __ LoadP(r7, FieldMemOperand(r2, ConsString::kSecondOffset));
-  __ CompareRoot(r7, Heap::kempty_stringRootIndex);
-  __ bne(&runtime);
-  __ LoadP(r7, FieldMemOperand(r2, ConsString::kFirstOffset));
-  // Update instance type.
-  __ LoadP(r3, FieldMemOperand(r7, HeapObject::kMapOffset));
-  __ LoadlB(r3, FieldMemOperand(r3, Map::kInstanceTypeOffset));
-  __ b(&underlying_unpacked);
-
-  __ bind(&sliced_string);
-  // Sliced string.  Fetch parent and correct start index by offset.
-  __ LoadP(r7, FieldMemOperand(r2, SlicedString::kParentOffset));
-  __ LoadP(r6, FieldMemOperand(r2, SlicedString::kOffsetOffset));
-  __ SmiUntag(r3, r6);
-  __ AddP(r5, r3);  // Add offset to index.
-  // Update instance type.
-  __ LoadP(r3, FieldMemOperand(r7, HeapObject::kMapOffset));
-  __ LoadlB(r3, FieldMemOperand(r3, Map::kInstanceTypeOffset));
-  __ b(&underlying_unpacked);
-
-  __ bind(&seq_or_external_string);
-  // Sequential or external string.  Just move string to the expected register.
-  __ LoadRR(r7, r2);
-
-  __ bind(&underlying_unpacked);
-
-  if (FLAG_string_slices) {
-    Label copy_routine;
-    // r7: underlying subject string
-    // r3: instance type of underlying subject string
-    // r4: length
-    // r5: adjusted start index (untagged)
-    __ CmpP(r4, Operand(SlicedString::kMinLength));
-    // Short slice.  Copy instead of slicing.
-    __ blt(&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);
-    __ mov(r0, Operand(kStringEncodingMask));
-    __ AndP(r0, r3);
-    __ beq(&two_byte_slice);
-    __ AllocateOneByteSlicedString(r2, r4, r8, r9, &runtime);
-    __ b(&set_slice_header);
-    __ bind(&two_byte_slice);
-    __ AllocateTwoByteSlicedString(r2, r4, r8, r9, &runtime);
-    __ bind(&set_slice_header);
-    __ SmiTag(r5);
-    __ StoreP(r7, FieldMemOperand(r2, SlicedString::kParentOffset));
-    __ StoreP(r5, FieldMemOperand(r2, SlicedString::kOffsetOffset));
-    __ b(&return_r2);
-
-    __ bind(&copy_routine);
-  }
-
-  // r7: underlying subject string
-  // r3: instance type of underlying subject string
-  // r4: length
-  // r5: adjusted start index (untagged)
-  Label two_byte_sequential, sequential_string, allocate_result;
-  STATIC_ASSERT(kExternalStringTag != 0);
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ mov(r0, Operand(kExternalStringTag));
-  __ AndP(r0, r3);
-  __ beq(&sequential_string);
-
-  // Handle external string.
-  // Rule out short external strings.
-  STATIC_ASSERT(kShortExternalStringTag != 0);
-  __ mov(r0, Operand(kShortExternalStringTag));
-  __ AndP(r0, r3);
-  __ bne(&runtime);
-  __ LoadP(r7, FieldMemOperand(r7, ExternalString::kResourceDataOffset));
-  // r7 already points to the first character of underlying string.
-  __ b(&allocate_result);
-
-  __ bind(&sequential_string);
-  // Locate first character of underlying subject string.
-  STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
-  __ AddP(r7, Operand(SeqOneByteString::kHeaderSize - kHeapObjectTag));
-
-  __ bind(&allocate_result);
-  // Sequential acii string.  Allocate the result.
-  STATIC_ASSERT((kOneByteStringTag & kStringEncodingMask) != 0);
-  __ mov(r0, Operand(kStringEncodingMask));
-  __ AndP(r0, r3);
-  __ beq(&two_byte_sequential);
-
-  // Allocate and copy the resulting one-byte string.
-  __ AllocateOneByteString(r2, r4, r6, r8, r9, &runtime);
-
-  // Locate first character of substring to copy.
-  __ AddP(r7, r5);
-  // Locate first character of result.
-  __ AddP(r3, r2, Operand(SeqOneByteString::kHeaderSize - kHeapObjectTag));
-
-  // r2: result string
-  // r3: first character of result string
-  // r4: result string length
-  // r7: first character of substring to copy
-  STATIC_ASSERT((SeqOneByteString::kHeaderSize & kObjectAlignmentMask) == 0);
-  StringHelper::GenerateCopyCharacters(masm, r3, r7, r4, r5,
-                                       String::ONE_BYTE_ENCODING);
-  __ b(&return_r2);
-
-  // Allocate and copy the resulting two-byte string.
-  __ bind(&two_byte_sequential);
-  __ AllocateTwoByteString(r2, r4, r6, r8, r9, &runtime);
-
-  // Locate first character of substring to copy.
-  __ ShiftLeftP(r3, r5, Operand(1));
-  __ AddP(r7, r3);
-  // Locate first character of result.
-  __ AddP(r3, r2, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-
-  // r2: result string.
-  // r3: first character of result.
-  // r4: result length.
-  // r7: first character of substring to copy.
-  STATIC_ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
-  StringHelper::GenerateCopyCharacters(masm, r3, r7, r4, r5,
-                                       String::TWO_BYTE_ENCODING);
-
-  __ bind(&return_r2);
-  Counters* counters = isolate()->counters();
-  __ IncrementCounter(counters->sub_string_native(), 1, r5, r6);
-  __ Drop(3);
-  __ Ret();
-
-  // Just jump to runtime to create the sub string.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kSubString);
-
-  __ bind(&single_char);
-  // r2: original string
-  // r3: instance type
-  // r4: length
-  // r5: from index (untagged)
-  __ SmiTag(r5, r5);
-  StringCharAtGenerator generator(r2, r5, r4, r2, &runtime, &runtime, &runtime,
-                                  RECEIVER_IS_STRING);
-  generator.GenerateFast(masm);
-  __ Drop(3);
-  __ Ret();
-  generator.SkipSlow(masm, &runtime);
-}
-
 void ToStringStub::Generate(MacroAssembler* masm) {
   // The ToString stub takes one argument in r2.
   Label done;
   Label is_number;
   __ JumpIfSmi(r2, &is_number);
 
   __ CompareObjectType(r2, r3, r3, FIRST_NONSTRING_TYPE);
   // r2: receiver
   // r3: receiver instance type
   __ blt(&done);
@@ skipping 2911 matching lines @@
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            kStackUnwindSpace, NULL, return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390