Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(34)

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

Issue 2365413002: Revert of [stubs] Port SubStringStub to TurboFan (Closed)
Patch Set: Created 4 years, 3 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « no previous file | src/arm64/code-stubs-arm64.cc » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 6f253cbfc8751fae9aca01790632b9140c9216be..5e35534b76404af2d28c529dcd1cea51a35aea4e 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2127,6 +2127,231 @@
__ 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;
+
+ __ Ldrd(r2, r3, MemOperand(sp, kToOffset));
+ STATIC_ASSERT(kFromOffset == kToOffset + 4);
+ STATIC_ASSERT(kSmiTag == 0);
+ STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
+
+ // Arithmetic shift right by one un-smi-tags. In this case we rotate right
+ // instead because we bail out on non-smi values: ROR and ASR are equivalent
+ // for smis but they set the flags in a way that's easier to optimize.
+ __ mov(r2, Operand(r2, ROR, 1), SetCC);
+ __ mov(r3, Operand(r3, ROR, 1), SetCC, cc);
+ // If either to or from had the smi tag bit set, then C is set now, and N
+ // has the same value: we rotated by 1, so the bottom bit is now the top bit.
+ // We want to bailout to runtime here if From is negative. In that case, the
+ // next instruction is not executed and we fall through to bailing out to
+ // runtime.
+ // Executed if both r2 and r3 are untagged integers.
+ __ sub(r2, r2, Operand(r3), SetCC, cc);
+ // One of the above un-smis or the above SUB could have set N==1.
+ __ b(mi, &runtime); // Either "from" or "to" is not an smi, or from > to.
+
+ // Make sure first argument is a string.
+ __ ldr(r0, MemOperand(sp, kStringOffset));
+ __ JumpIfSmi(r0, &runtime);
+ Condition is_string = masm->IsObjectStringType(r0, r1);
+ __ b(NegateCondition(is_string), &runtime);
+
+ Label single_char;
+ __ cmp(r2, Operand(1));
+ __ b(eq, &single_char);
+
+ // Short-cut for the case of trivial substring.
+ Label return_r0;
+ // r0: original string
+ // r2: result string length
+ __ ldr(r4, FieldMemOperand(r0, String::kLengthOffset));
+ __ cmp(r2, Operand(r4, ASR, 1));
+ // Return original string.
+ __ b(eq, &return_r0);
+ // Longer than original string's length or negative: unsafe arguments.
+ __ b(hi, &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 r5.
+ // r0: original string
+ // r1: instance type
+ // r2: length
+ // r3: 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);
+ __ tst(r1, Operand(kIsIndirectStringMask));
+ __ b(eq, &seq_or_external_string);
+
+ __ tst(r1, Operand(kSlicedNotConsMask));
+ __ b(ne, &sliced_string);
+ // Cons string. Check whether it is flat, then fetch first part.
+ __ ldr(r5, FieldMemOperand(r0, ConsString::kSecondOffset));
+ __ CompareRoot(r5, Heap::kempty_stringRootIndex);
+ __ b(ne, &runtime);
+ __ ldr(r5, FieldMemOperand(r0, ConsString::kFirstOffset));
+ // Update instance type.
+ __ ldr(r1, FieldMemOperand(r5, HeapObject::kMapOffset));
+ __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
+ __ jmp(&underlying_unpacked);
+
+ __ bind(&sliced_string);
+ // Sliced string. Fetch parent and correct start index by offset.
+ __ ldr(r5, FieldMemOperand(r0, SlicedString::kParentOffset));
+ __ ldr(r4, FieldMemOperand(r0, SlicedString::kOffsetOffset));
+ __ add(r3, r3, Operand(r4, ASR, 1)); // Add offset to index.
+ // Update instance type.
+ __ ldr(r1, FieldMemOperand(r5, HeapObject::kMapOffset));
+ __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
+ __ jmp(&underlying_unpacked);
+
+ __ bind(&seq_or_external_string);
+ // Sequential or external string. Just move string to the expected register.
+ __ mov(r5, r0);
+
+ __ bind(&underlying_unpacked);
+
+ if (FLAG_string_slices) {
+ Label copy_routine;
+ // r5: underlying subject string
+ // r1: instance type of underlying subject string
+ // r2: length
+ // r3: adjusted start index (untagged)
+ __ cmp(r2, Operand(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 anyways due to externalized strings.
+ Label two_byte_slice, set_slice_header;
+ STATIC_ASSERT((kStringEncodingMask & kOneByteStringTag) != 0);
+ STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
+ __ tst(r1, Operand(kStringEncodingMask));
+ __ b(eq, &two_byte_slice);
+ __ AllocateOneByteSlicedString(r0, r2, r6, r4, &runtime);
+ __ jmp(&set_slice_header);
+ __ bind(&two_byte_slice);
+ __ AllocateTwoByteSlicedString(r0, r2, r6, r4, &runtime);
+ __ bind(&set_slice_header);
+ __ mov(r3, Operand(r3, LSL, 1));
+ __ str(r5, FieldMemOperand(r0, SlicedString::kParentOffset));
+ __ str(r3, FieldMemOperand(r0, SlicedString::kOffsetOffset));
+ __ jmp(&return_r0);
+
+ __ bind(&copy_routine);
+ }
+
+ // r5: underlying subject string
+ // r1: instance type of underlying subject string
+ // r2: length
+ // r3: adjusted start index (untagged)
+ Label two_byte_sequential, sequential_string, allocate_result;
+ STATIC_ASSERT(kExternalStringTag != 0);
+ STATIC_ASSERT(kSeqStringTag == 0);
+ __ tst(r1, Operand(kExternalStringTag));
+ __ b(eq, &sequential_string);
+
+ // Handle external string.
+ // Rule out short external strings.
+ STATIC_ASSERT(kShortExternalStringTag != 0);
+ __ tst(r1, Operand(kShortExternalStringTag));
+ __ b(ne, &runtime);
+ __ ldr(r5, FieldMemOperand(r5, ExternalString::kResourceDataOffset));
+ // r5 already points to the first character of underlying string.
+ __ jmp(&allocate_result);
+
+ __ bind(&sequential_string);
+ // Locate first character of underlying subject string.
+ STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
+ __ add(r5, r5, Operand(SeqOneByteString::kHeaderSize - kHeapObjectTag));
+
+ __ bind(&allocate_result);
+ // Sequential acii string. Allocate the result.
+ STATIC_ASSERT((kOneByteStringTag & kStringEncodingMask) != 0);
+ __ tst(r1, Operand(kStringEncodingMask));
+ __ b(eq, &two_byte_sequential);
+
+ // Allocate and copy the resulting one-byte string.
+ __ AllocateOneByteString(r0, r2, r4, r6, r1, &runtime);
+
+ // Locate first character of substring to copy.
+ __ add(r5, r5, r3);
+ // Locate first character of result.
+ __ add(r1, r0, Operand(SeqOneByteString::kHeaderSize - kHeapObjectTag));
+
+ // r0: result string
+ // r1: first character of result string
+ // r2: result string length
+ // r5: first character of substring to copy
+ STATIC_ASSERT((SeqOneByteString::kHeaderSize & kObjectAlignmentMask) == 0);
+ StringHelper::GenerateCopyCharacters(
+ masm, r1, r5, r2, r3, String::ONE_BYTE_ENCODING);
+ __ jmp(&return_r0);
+
+ // Allocate and copy the resulting two-byte string.
+ __ bind(&two_byte_sequential);
+ __ AllocateTwoByteString(r0, r2, r4, r6, r1, &runtime);
+
+ // Locate first character of substring to copy.
+ STATIC_ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
+ __ add(r5, r5, Operand(r3, LSL, 1));
+ // Locate first character of result.
+ __ add(r1, r0, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+
+ // r0: result string.
+ // r1: first character of result.
+ // r2: result length.
+ // r5: first character of substring to copy.
+ STATIC_ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
+ StringHelper::GenerateCopyCharacters(
+ masm, r1, r5, r2, r3, String::TWO_BYTE_ENCODING);
+
+ __ bind(&return_r0);
+ Counters* counters = isolate()->counters();
+ __ IncrementCounter(counters->sub_string_native(), 1, r3, r4);
+ __ Drop(3);
+ __ Ret();
+
+ // Just jump to runtime to create the sub string.
+ __ bind(&runtime);
+ __ TailCallRuntime(Runtime::kSubString);
+
+ __ bind(&single_char);
+ // r0: original string
+ // r1: instance type
+ // r2: length
+ // r3: from index (untagged)
+ __ SmiTag(r3, r3);
+ StringCharAtGenerator generator(r0, r3, r2, r0, &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 r0.
Label is_number;
« no previous file with comments | « no previous file | src/arm64/code-stubs-arm64.cc » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698