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Unified Diff: src/arm64/code-stubs-arm64.cc

Issue 2355793003: [stubs] Port SubStringStub to TurboFan (Closed)
Patch Set: Address comments Created 4 years, 3 months ago
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Index: src/arm64/code-stubs-arm64.cc
diff --git a/src/arm64/code-stubs-arm64.cc b/src/arm64/code-stubs-arm64.cc
index 3754ea4a3d931024917baad6dc60554b9c91f928..071abde92a27cc5dc742f4bd5820f29b0c6dd78f 100644
--- a/src/arm64/code-stubs-arm64.cc
+++ b/src/arm64/code-stubs-arm64.cc
@@ -2673,257 +2673,6 @@ void CompareICStub::GenerateMiss(MacroAssembler* masm) {
__ Jump(stub_entry);
}
-
-void SubStringStub::Generate(MacroAssembler* masm) {
- ASM_LOCATION("SubStringStub::Generate");
- Label runtime;
-
- // Stack frame on entry.
- // lr: return address
- // jssp[0]: substring "to" offset
- // jssp[8]: substring "from" offset
- // jssp[16]: pointer to string object
-
- // 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 (in debug mode.)
- // If any of these assumptions fail, we call the runtime system.
-
- static const int kToOffset = 0 * kPointerSize;
- static const int kFromOffset = 1 * kPointerSize;
- static const int kStringOffset = 2 * kPointerSize;
-
- Register to = x0;
- Register from = x15;
- Register input_string = x10;
- Register input_length = x11;
- Register input_type = x12;
- Register result_string = x0;
- Register result_length = x1;
- Register temp = x3;
-
- __ Peek(to, kToOffset);
- __ Peek(from, kFromOffset);
-
- // Check that both from and to are smis. If not, jump to runtime.
- __ JumpIfEitherNotSmi(from, to, &runtime);
- __ SmiUntag(from);
- __ SmiUntag(to);
-
- // Calculate difference between from and to. If to < from, branch to runtime.
- __ Subs(result_length, to, from);
- __ B(mi, &runtime);
-
- // Check from is positive.
- __ Tbnz(from, kWSignBit, &runtime);
-
- // Make sure first argument is a string.
- __ Peek(input_string, kStringOffset);
- __ JumpIfSmi(input_string, &runtime);
- __ IsObjectJSStringType(input_string, input_type, &runtime);
-
- Label single_char;
- __ Cmp(result_length, 1);
- __ B(eq, &single_char);
-
- // Short-cut for the case of trivial substring.
- Label return_x0;
- __ Ldrsw(input_length,
- UntagSmiFieldMemOperand(input_string, String::kLengthOffset));
-
- __ Cmp(result_length, input_length);
- __ CmovX(x0, input_string, eq);
- // Return original string.
- __ B(eq, &return_x0);
-
- // Longer than original string's length or negative: unsafe arguments.
- __ B(hi, &runtime);
-
- // Shorter than original string's length: an actual substring.
-
- // x0 to substring end character offset
- // x1 result_length length of substring result
- // x10 input_string pointer to input string object
- // x10 unpacked_string pointer to unpacked string object
- // x11 input_length length of input string
- // x12 input_type instance type of input string
- // x15 from substring start character offset
-
- // Deal with different string types: update the index if necessary and put
- // the underlying string into register unpacked_string.
- Label underlying_unpacked, sliced_string, seq_or_external_string;
- Label update_instance_type;
- // If the string is not indirect, it can only be sequential or external.
- STATIC_ASSERT(kIsIndirectStringMask == (kSlicedStringTag & kConsStringTag));
- STATIC_ASSERT(kIsIndirectStringMask != 0);
-
- // Test for string types, and branch/fall through to appropriate unpacking
- // code.
- __ Tst(input_type, kIsIndirectStringMask);
- __ B(eq, &seq_or_external_string);
- __ Tst(input_type, kSlicedNotConsMask);
- __ B(ne, &sliced_string);
-
- Register unpacked_string = input_string;
-
- // Cons string. Check whether it is flat, then fetch first part.
- __ Ldr(temp, FieldMemOperand(input_string, ConsString::kSecondOffset));
- __ JumpIfNotRoot(temp, Heap::kempty_stringRootIndex, &runtime);
- __ Ldr(unpacked_string,
- FieldMemOperand(input_string, ConsString::kFirstOffset));
- __ B(&update_instance_type);
-
- __ Bind(&sliced_string);
- // Sliced string. Fetch parent and correct start index by offset.
- __ Ldrsw(temp,
- UntagSmiFieldMemOperand(input_string, SlicedString::kOffsetOffset));
- __ Add(from, from, temp);
- __ Ldr(unpacked_string,
- FieldMemOperand(input_string, SlicedString::kParentOffset));
-
- __ Bind(&update_instance_type);
- __ Ldr(temp, FieldMemOperand(unpacked_string, HeapObject::kMapOffset));
- __ Ldrb(input_type, FieldMemOperand(temp, Map::kInstanceTypeOffset));
- // Now control must go to &underlying_unpacked. Since the no code is generated
- // before then we fall through instead of generating a useless branch.
-
- __ Bind(&seq_or_external_string);
- // Sequential or external string. Registers unpacked_string and input_string
- // alias, so there's nothing to do here.
- // Note that if code is added here, the above code must be updated.
-
- // x0 result_string pointer to result string object (uninit)
- // x1 result_length length of substring result
- // x10 unpacked_string pointer to unpacked string object
- // x11 input_length length of input string
- // x12 input_type instance type of input string
- // x15 from substring start character offset
- __ Bind(&underlying_unpacked);
-
- if (FLAG_string_slices) {
- Label copy_routine;
- __ Cmp(result_length, SlicedString::kMinLength);
- // Short slice. Copy instead of slicing.
- __ B(lt, &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 anyway due to externalized strings.
- Label two_byte_slice, set_slice_header;
- STATIC_ASSERT((kStringEncodingMask & kOneByteStringTag) != 0);
- STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
- __ Tbz(input_type, MaskToBit(kStringEncodingMask), &two_byte_slice);
- __ AllocateOneByteSlicedString(result_string, result_length, x3, x4,
- &runtime);
- __ B(&set_slice_header);
-
- __ Bind(&two_byte_slice);
- __ AllocateTwoByteSlicedString(result_string, result_length, x3, x4,
- &runtime);
-
- __ Bind(&set_slice_header);
- __ SmiTag(from);
- __ Str(from, FieldMemOperand(result_string, SlicedString::kOffsetOffset));
- __ Str(unpacked_string,
- FieldMemOperand(result_string, SlicedString::kParentOffset));
- __ B(&return_x0);
-
- __ Bind(&copy_routine);
- }
-
- // x0 result_string pointer to result string object (uninit)
- // x1 result_length length of substring result
- // x10 unpacked_string pointer to unpacked string object
- // x11 input_length length of input string
- // x12 input_type instance type of input string
- // x13 unpacked_char0 pointer to first char of unpacked string (uninit)
- // x13 substring_char0 pointer to first char of substring (uninit)
- // x14 result_char0 pointer to first char of result (uninit)
- // x15 from substring start character offset
- Register unpacked_char0 = x13;
- Register substring_char0 = x13;
- Register result_char0 = x14;
- Label two_byte_sequential, sequential_string, allocate_result;
- STATIC_ASSERT(kExternalStringTag != 0);
- STATIC_ASSERT(kSeqStringTag == 0);
-
- __ Tst(input_type, kExternalStringTag);
- __ B(eq, &sequential_string);
-
- __ Tst(input_type, kShortExternalStringTag);
- __ B(ne, &runtime);
- __ Ldr(unpacked_char0,
- FieldMemOperand(unpacked_string, ExternalString::kResourceDataOffset));
- // unpacked_char0 points to the first character of the underlying string.
- __ B(&allocate_result);
-
- __ Bind(&sequential_string);
- // Locate first character of underlying subject string.
- STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
- __ Add(unpacked_char0, unpacked_string,
- SeqOneByteString::kHeaderSize - kHeapObjectTag);
-
- __ Bind(&allocate_result);
- // Sequential one-byte string. Allocate the result.
- STATIC_ASSERT((kOneByteStringTag & kStringEncodingMask) != 0);
- __ Tbz(input_type, MaskToBit(kStringEncodingMask), &two_byte_sequential);
-
- // Allocate and copy the resulting one-byte string.
- __ AllocateOneByteString(result_string, result_length, x3, x4, x5, &runtime);
-
- // Locate first character of substring to copy.
- __ Add(substring_char0, unpacked_char0, from);
-
- // Locate first character of result.
- __ Add(result_char0, result_string,
- SeqOneByteString::kHeaderSize - kHeapObjectTag);
-
- STATIC_ASSERT((SeqOneByteString::kHeaderSize & kObjectAlignmentMask) == 0);
- __ CopyBytes(result_char0, substring_char0, result_length, x3, kCopyLong);
- __ B(&return_x0);
-
- // Allocate and copy the resulting two-byte string.
- __ Bind(&two_byte_sequential);
- __ AllocateTwoByteString(result_string, result_length, x3, x4, x5, &runtime);
-
- // Locate first character of substring to copy.
- __ Add(substring_char0, unpacked_char0, Operand(from, LSL, 1));
-
- // Locate first character of result.
- __ Add(result_char0, result_string,
- SeqTwoByteString::kHeaderSize - kHeapObjectTag);
-
- STATIC_ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
- __ Add(result_length, result_length, result_length);
- __ CopyBytes(result_char0, substring_char0, result_length, x3, kCopyLong);
-
- __ Bind(&return_x0);
- Counters* counters = isolate()->counters();
- __ IncrementCounter(counters->sub_string_native(), 1, x3, x4);
- __ Drop(3);
- __ Ret();
-
- __ Bind(&runtime);
- __ TailCallRuntime(Runtime::kSubString);
-
- __ bind(&single_char);
- // x1: result_length
- // x10: input_string
- // x12: input_type
- // x15: from (untagged)
- __ SmiTag(from);
- StringCharAtGenerator generator(input_string, from, result_length, x0,
- &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 x0.
Label is_number;
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