Tweaks to SubStringStub

Review URL: https://chromiumcodereview.appspot.com/9625003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10957 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 0010c82cf4288a02cbbb556f10e50ac08d1a2bd1..3a4ce7416f80f1b8b0e2b2699b5fab9c888c2394 100644 (file)
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -5930,8 +5930,8 @@ void SubStringStub::Generate(MacroAssembler* masm) {
 
   __ bind(&sliced_string);
   // Sliced string.  Fetch parent and correct start index by offset.
-  __ ldr(r4, FieldMemOperand(r0, SlicedString::kOffsetOffset));
   __ 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));
@@ -5969,8 +5969,8 @@ void SubStringStub::Generate(MacroAssembler* masm) {
     __ AllocateTwoByteSlicedString(r0, r2, r6, r7, &runtime);
     __ bind(&set_slice_header);
     __ mov(r3, Operand(r3, LSL, 1));
-    __ str(r3, FieldMemOperand(r0, SlicedString::kOffsetOffset));
     __ str(r5, FieldMemOperand(r0, SlicedString::kParentOffset));
+    __ str(r3, FieldMemOperand(r0, SlicedString::kOffsetOffset));
     __ jmp(&return_r0);
 
     __ bind(&copy_routine);

diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
index 5b6f6873c264326d8b843343161e556a79103884..54a1a348a93f4a1cb306ebeedaf3555ce0c9d93d 100644 (file)
--- a/src/ia32/code-stubs-ia32.cc
+++ b/src/ia32/code-stubs-ia32.cc
@@ -6155,7 +6155,6 @@ void SubStringStub::Generate(MacroAssembler* masm) {
   // ebx: instance type
 
   // Calculate length of sub string using the smi values.
-  Label result_longer_than_two;
   __ mov(ecx, Operand(esp, 1 * kPointerSize));  // To index.
   __ JumpIfNotSmi(ecx, &runtime);
   __ mov(edx, Operand(esp, 2 * kPointerSize));  // From index.
@@ -6168,43 +6167,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
   __ IncrementCounter(counters->sub_string_native(), 1);
   __ ret(3 * kPointerSize);
   __ bind(&not_original_string);
-  // Special handling of sub-strings of length 1 and 2. One character strings
-  // are handled in the runtime system (looked up in the single character
-  // cache). Two character strings are looked for in the symbol cache.
-  __ cmp(ecx, Immediate(Smi::FromInt(2)));
-  __ j(greater, &result_longer_than_two);
-  __ j(less, &runtime);
-
-  // Sub string of length 2 requested.
-  // eax: string
-  // ebx: instance type
-  // ecx: sub string length (smi, value is 2)
-  // edx: from index (smi)
-  __ JumpIfInstanceTypeIsNotSequentialAscii(ebx, ebx, &runtime);
-
-  // Get the two characters forming the sub string.
-  __ SmiUntag(edx);  // From index is no longer smi.
-  __ movzx_b(ebx, FieldOperand(eax, edx, times_1, SeqAsciiString::kHeaderSize));
-  __ movzx_b(ecx,
-             FieldOperand(eax, edx, times_1, SeqAsciiString::kHeaderSize + 1));
-
-  // Try to lookup two character string in symbol table.
-  Label combine_two_char, save_two_char;
-  StringHelper::GenerateTwoCharacterSymbolTableProbe(
-      masm, ebx, ecx, eax, edx, edi, &combine_two_char, &save_two_char);
-  __ IncrementCounter(counters->sub_string_native(), 1);
-  __ ret(3 * kPointerSize);
-
-  __ bind(&combine_two_char);
-  __ shl(ecx, kBitsPerByte);
-  __ or_(ebx, ecx);
-  __ bind(&save_two_char);
-  __ AllocateAsciiString(eax, 2, ecx, edx, &runtime);
-  __ mov_w(FieldOperand(eax, SeqAsciiString::kHeaderSize), ebx);
-  __ IncrementCounter(counters->sub_string_native(), 1);
-  __ ret(3 * kPointerSize);
 
-  __ bind(&result_longer_than_two);
   // eax: string
   // ebx: instance type
   // ecx: sub string length (smi)
@@ -6271,11 +6234,11 @@ void SubStringStub::Generate(MacroAssembler* masm) {
     __ bind(&two_byte_slice);
     __ AllocateTwoByteSlicedString(eax, ebx, no_reg, &runtime);
     __ bind(&set_slice_header);
-    __ mov(FieldOperand(eax, SlicedString::kOffsetOffset), edx);
     __ mov(FieldOperand(eax, SlicedString::kLengthOffset), ecx);
-    __ mov(FieldOperand(eax, SlicedString::kParentOffset), edi);
     __ mov(FieldOperand(eax, SlicedString::kHashFieldOffset),
            Immediate(String::kEmptyHashField));
+    __ mov(FieldOperand(eax, SlicedString::kParentOffset), edi);
+    __ mov(FieldOperand(eax, SlicedString::kOffsetOffset), edx);
     __ IncrementCounter(counters->sub_string_native(), 1);
     __ ret(3 * kPointerSize);
 

diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index a928dc0aeb5c942ffb130999aa96881705fa6753..3eaa524918156912e69058df6b717727ea70f4a3 100644 (file)
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -6151,8 +6151,8 @@ void SubStringStub::Generate(MacroAssembler* masm) {
 
   __ bind(&sliced_string);
   // Sliced string.  Fetch parent and correct start index by offset.
-  __ lw(t0, FieldMemOperand(v0, SlicedString::kOffsetOffset));
   __ lw(t1, FieldMemOperand(v0, SlicedString::kParentOffset));
+  __ lw(t0, FieldMemOperand(v0, SlicedString::kOffsetOffset));
   __ sra(t0, t0, 1);  // Add offset to index.
   __ Addu(a3, a3, t0);
   // Update instance type.
@@ -6190,8 +6190,8 @@ void SubStringStub::Generate(MacroAssembler* masm) {
     __ AllocateTwoByteSlicedString(v0, a2, t2, t3, &runtime);
     __ bind(&set_slice_header);
     __ sll(a3, a3, 1);
-    __ sw(a3, FieldMemOperand(v0, SlicedString::kOffsetOffset));
     __ sw(t1, FieldMemOperand(v0, SlicedString::kParentOffset));
+    __ sw(a3, FieldMemOperand(v0, SlicedString::kOffsetOffset));
     __ jmp(&return_v0);
 
     __ bind(&copy_routine);

diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 2bfb0043bc50c6beaea831b862c2abff02669b18..1354e62b44bd190d08e7785ded4f45fb697798c8 100644 (file)
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -5229,12 +5229,12 @@ void SubStringStub::Generate(MacroAssembler* masm) {
     __ bind(&two_byte_slice);
     __ AllocateTwoByteSlicedString(rax, rbx, r14, &runtime);
     __ bind(&set_slice_header);
-    __ movq(FieldOperand(rax, SlicedString::kOffsetOffset), rdx);
     __ Integer32ToSmi(rcx, rcx);
     __ movq(FieldOperand(rax, SlicedString::kLengthOffset), rcx);
-    __ movq(FieldOperand(rax, SlicedString::kParentOffset), rdi);
     __ movq(FieldOperand(rax, SlicedString::kHashFieldOffset),
            Immediate(String::kEmptyHashField));
+    __ movq(FieldOperand(rax, SlicedString::kParentOffset), rdi);
+    __ movq(FieldOperand(rax, SlicedString::kOffsetOffset), rdx);
     __ IncrementCounter(counters->sub_string_native(), 1);
     __ ret(kArgumentsSize);