Porting r10023 and r10054 to x64 (pointer cache for external strings).

Review URL: http://codereview.chromium.org/8662009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10058 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/codegen.h

@@ -94,23 +94,6 @@ class ElementsTransitionGenerator : public AllStatic {
   DISALLOW_COPY_AND_ASSIGN(ElementsTransitionGenerator);
 };
 
-
-class StringCharLoadGenerator : public AllStatic {
- public:
-  // Generates the code for handling different string types and loading the
-  // indexed character into |result|.  We expect |index| as untagged input and
-  // |result| as untagged output.
-  static void Generate(MacroAssembler* masm,
-                       Factory* factory,
-                       Register string,
-                       Register index,
-                       Register result,
-                       Label* call_runtime);
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(StringCharLoadGenerator);
-};
-
 } }  // namespace v8::internal
 
 #endif  // V8_CODEGEN_H_

src/ia32/codegen-ia32.cc

@@ -579,7 +579,7 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
   __ movzx_b(result, Operand(result, index, times_1, 0));
   __ jmp(&done);
 
-  // Handle conses.
+  // Handle cons strings.
   // Check whether the right hand side is the empty string (i.e. if
   // this is really a flat string in a cons string). If that is not
   // the case we would rather go to the runtime system now to flatten
@@ -594,11 +594,9 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
   __ mov(result, FieldOperand(string, HeapObject::kMapOffset));
   __ movzx_b(result, FieldOperand(result, Map::kInstanceTypeOffset));
 
-  // Check whether the string is sequential. The only non-sequential
-  // shapes we support have just been unwrapped above.
-  // Note that if the original string is a cons or slice with an external
-  // string as underlying string, we pass that unpacked underlying string with
-  // the adjusted index to the runtime function.
+  // Distinguish sequential and external strings. Only these two string
+  // representations can reach here (slices and flat cons strings have been
+  // reduced to the underlying sequential or external string).
   __ bind(&check_sequential);
   STATIC_ASSERT(kSeqStringTag == 0);
   __ test(result, Immediate(kStringRepresentationMask));

src/ia32/codegen-ia32.h

@@ -72,6 +72,22 @@ class CodeGenerator {
 };
 
 
+class StringCharLoadGenerator : public AllStatic {
+ public:
+  // Generates the code for handling different string types and loading the
+  // indexed character into |result|.  We expect |index| as untagged input and
+  // |result| as untagged output.
+  static void Generate(MacroAssembler* masm,
+                       Factory* factory,
+                       Register string,
+                       Register index,
+                       Register result,
+                       Label* call_runtime);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(StringCharLoadGenerator);
+};
+
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_CODEGEN_IA32_H_

src/x64/code-stubs-x64.cc

@@ -4157,70 +4157,11 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   __ SmiCompare(index_, FieldOperand(object_, String::kLengthOffset));
   __ j(above_equal, index_out_of_range_);
 
-  // We need special handling for non-flat strings.
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ testb(result_, Immediate(kStringRepresentationMask));
-  __ j(zero, &flat_string);
+  __ SmiToInteger32(index_, index_);
 
-  // Handle non-flat strings.
-  __ and_(result_, Immediate(kStringRepresentationMask));
-  STATIC_ASSERT(kConsStringTag < kExternalStringTag);
-  STATIC_ASSERT(kSlicedStringTag > kExternalStringTag);
-  __ cmpb(result_, Immediate(kExternalStringTag));
-  __ j(greater, &sliced_string);
-  __ j(equal, &call_runtime_);
-
-  // ConsString.
-  // Check whether the right hand side is the empty string (i.e. if
-  // this is really a flat string in a cons string). If that is not
-  // the case we would rather go to the runtime system now to flatten
-  // the string.
-  Label assure_seq_string;
-  __ CompareRoot(FieldOperand(object_, ConsString::kSecondOffset),
-                 Heap::kEmptyStringRootIndex);
-  __ j(not_equal, &call_runtime_);
-  // Get the first of the two parts.
-  __ movq(object_, FieldOperand(object_, ConsString::kFirstOffset));
-  __ jmp(&assure_seq_string, Label::kNear);
+  StringCharLoadGenerator::Generate(
+      masm, object_, index_, result_, &call_runtime_);
 
-  // SlicedString, unpack and add offset.
-  __ bind(&sliced_string);
-  __ addq(index_, FieldOperand(object_, SlicedString::kOffsetOffset));
-  __ movq(object_, FieldOperand(object_, SlicedString::kParentOffset));
-
-  // Assure that we are dealing with a sequential string. Go to runtime if not.
-  // Note that if the original string is a cons or slice with an external
-  // string as underlying string, we pass that unpacked underlying string with
-  // the adjusted index to the runtime function.
-  __ bind(&assure_seq_string);
-  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
-  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ testb(result_, Immediate(kStringRepresentationMask));
-  __ j(not_zero, &call_runtime_);
-
-  // Check for 1-byte or 2-byte string.
-  __ bind(&flat_string);
-  STATIC_ASSERT((kStringEncodingMask & kAsciiStringTag) != 0);
-  STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
-  __ SmiToInteger32(index_, index_);
-  __ testb(result_, Immediate(kStringEncodingMask));
-  __ j(not_zero, &ascii_string);
-
-  // 2-byte string.
-  // Load the 2-byte character code into the result register.
-  __ movzxwl(result_, FieldOperand(object_,
-                                   index_, times_2,
-                                   SeqTwoByteString::kHeaderSize));
-  __ jmp(&got_char_code);
-
-  // ASCII string.
-  // Load the byte into the result register.
-  __ bind(&ascii_string);
-  __ movzxbl(result_, FieldOperand(object_,
-                                   index_, times_1,
-                                   SeqAsciiString::kHeaderSize));
-  __ bind(&got_char_code);
   __ Integer32ToSmi(result_, result_);
   __ bind(&exit_);
 }
@@ -4270,6 +4211,7 @@ void StringCharCodeAtGenerator::GenerateSlow(
   __ bind(&call_runtime_);
   call_helper.BeforeCall(masm);
   __ push(object_);
+  __ Integer32ToSmi(index_, index_);
   __ push(index_);
   __ CallRuntime(Runtime::kStringCharCodeAt, 2);
   if (!result_.is(rax)) {

src/x64/codegen-x64.cc

@@ -367,6 +367,108 @@ void ElementsTransitionGenerator::GenerateDoubleToObject(
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 }
 
+
+void StringCharLoadGenerator::Generate(MacroAssembler* masm,
+                                       Register string,
+                                       Register index,
+                                       Register result,
+                                       Label* call_runtime) {
+  // Fetch the instance type of the receiver into result register.
+  __ movq(result, FieldOperand(string, HeapObject::kMapOffset));
+  __ movzxbl(result, FieldOperand(result, Map::kInstanceTypeOffset));
+
+  // We need special handling for indirect strings.
+  Label check_sequential;
+  __ testb(result, Immediate(kIsIndirectStringMask));
+  __ j(zero, &check_sequential);
+
+  // Dispatch on the indirect string shape: slice or cons.
+  Label cons_string;
+  __ testb(result, Immediate(kSlicedNotConsMask));
+  __ j(zero, &cons_string, Label::kNear);
+
+  // Handle slices.
+  Label indirect_string_loaded;
+  __ SmiToInteger32(result, FieldOperand(string, SlicedString::kOffsetOffset));
+  __ addq(index, result);
+  __ movq(string, FieldOperand(string, SlicedString::kParentOffset));
+  __ jmp(&indirect_string_loaded, Label::kNear);
+
+  // Handle external strings.
+  Label external_string, ascii_external, done;
+  __ bind(&external_string);
+  if (FLAG_debug_code) {
+    // Assert that we do not have a cons or slice (indirect strings) here.
+    // Sequential strings have already been ruled out.
+    __ testb(result, Immediate(kIsIndirectStringMask));
+    __ Assert(zero, "external string expected, but not found");
+  }
+  // Rule out short external strings.
+  STATIC_CHECK(kShortExternalStringTag != 0);
+  __ testb(result, Immediate(kShortExternalStringTag));
+  __ j(not_zero, call_runtime);
+  // Check encoding.
+  STATIC_ASSERT(kTwoByteStringTag == 0);
+  __ testb(result, Immediate(kStringEncodingMask));
+  __ movq(result, FieldOperand(string, ExternalString::kResourceDataOffset));
+  __ j(not_equal, &ascii_external, Label::kNear);
+  // Two-byte string.
+  __ movzxwl(result, Operand(result, index, times_2, 0));
+  __ jmp(&done);
+  __ bind(&ascii_external);
+  // Ascii string.
+  __ movzxbl(result, Operand(result, index, times_1, 0));
+  __ jmp(&done);
+
+  // Handle cons strings.
+  // Check whether the right hand side is the empty string (i.e. if
+  // this is really a flat string in a cons string). If that is not
+  // the case we would rather go to the runtime system now to flatten
+  // the string.
+  __ bind(&cons_string);
+  __ CompareRoot(FieldOperand(string, ConsString::kSecondOffset),
+                 Heap::kEmptyStringRootIndex);
+  __ j(not_equal, call_runtime);
+  __ movq(string, FieldOperand(string, ConsString::kFirstOffset));
+
+  __ bind(&indirect_string_loaded);
+  __ movq(result, FieldOperand(string, HeapObject::kMapOffset));
+  __ movzxbl(result, FieldOperand(result, Map::kInstanceTypeOffset));
+
+  // Distinguish sequential and external strings. Only these two string
+  // representations can reach here (slices and flat cons strings have been
+  // reduced to the underlying sequential or external string).
+  __ bind(&check_sequential);
+  STATIC_ASSERT(kSeqStringTag == 0);
+  __ testb(result, Immediate(kStringRepresentationMask));
+  __ j(not_zero, &external_string);
+
+  // Dispatch on the encoding: ASCII or two-byte.
+  Label ascii_string;
+  STATIC_ASSERT((kStringEncodingMask & kAsciiStringTag) != 0);
+  STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
+  __ testb(result, Immediate(kStringEncodingMask));
+  __ j(not_zero, &ascii_string, Label::kNear);
+
+  // Two-byte string.
+  // Load the two-byte character code into the result register.
+  STATIC_ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
+  __ movzxwl(result, FieldOperand(string,
+                                  index,
+                                  times_2,
+                                  SeqTwoByteString::kHeaderSize));
+  __ jmp(&done, Label::kNear);
+
+  // ASCII string.
+  // Load the byte into the result register.
+  __ bind(&ascii_string);
+  __ movzxbl(result, FieldOperand(string,
+                                  index,
+                                  times_1,
+                                  SeqAsciiString::kHeaderSize));
+  __ bind(&done);
+}
+
 #undef __
 
 } }  // namespace v8::internal

src/x64/codegen-x64.h

@@ -69,6 +69,21 @@ class CodeGenerator: public AstVisitor {
 };
 
 
+class StringCharLoadGenerator : public AllStatic {
+ public:
+  // Generates the code for handling different string types and loading the
+  // indexed character into |result|.  We expect |index| as untagged input and
+  // |result| as untagged output.
+  static void Generate(MacroAssembler* masm,
+                       Register string,
+                       Register index,
+                       Register result,
+                       Label* call_runtime);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(StringCharLoadGenerator);
+};
+
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODEGEN_X64_H_

src/x64/lithium-codegen-x64.cc

@@ -3306,84 +3306,14 @@ void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
     LStringCharCodeAt* instr_;
   };
 
-  Register string = ToRegister(instr->string());
-  Register index = ToRegister(instr->index());
-  Register result = ToRegister(instr->result());
-
   DeferredStringCharCodeAt* deferred =
       new DeferredStringCharCodeAt(this, instr);
 
-  // Fetch the instance type of the receiver into result register.
-  __ movq(result, FieldOperand(string, HeapObject::kMapOffset));
-  __ movzxbl(result, FieldOperand(result, Map::kInstanceTypeOffset));
-
-  // We need special handling for indirect strings.
-  Label check_sequential;
-  __ testb(result, Immediate(kIsIndirectStringMask));
-  __ j(zero, &check_sequential, Label::kNear);
-
-  // Dispatch on the indirect string shape: slice or cons.
-  Label cons_string;
-  __ testb(result, Immediate(kSlicedNotConsMask));
-  __ j(zero, &cons_string, Label::kNear);
-
-  // Handle slices.
-  Label indirect_string_loaded;
-  __ SmiToInteger32(result, FieldOperand(string, SlicedString::kOffsetOffset));
-  __ addq(index, result);
-  __ movq(string, FieldOperand(string, SlicedString::kParentOffset));
-  __ jmp(&indirect_string_loaded, Label::kNear);
-
-  // Handle conses.
-  // Check whether the right hand side is the empty string (i.e. if
-  // this is really a flat string in a cons string). If that is not
-  // the case we would rather go to the runtime system now to flatten
-  // the string.
-  __ bind(&cons_string);
-  __ CompareRoot(FieldOperand(string, ConsString::kSecondOffset),
-                 Heap::kEmptyStringRootIndex);
-  __ j(not_equal, deferred->entry());
-  __ movq(string, FieldOperand(string, ConsString::kFirstOffset));
-
-  __ bind(&indirect_string_loaded);
-  __ movq(result, FieldOperand(string, HeapObject::kMapOffset));
-  __ movzxbl(result, FieldOperand(result, Map::kInstanceTypeOffset));
-
-  // Check whether the string is sequential. The only non-sequential
-  // shapes we support have just been unwrapped above.
-  // Note that if the original string is a cons or slice with an external
-  // string as underlying string, we pass that unpacked underlying string with
-  // the adjusted index to the runtime function.
-  __ bind(&check_sequential);
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ testb(result, Immediate(kStringRepresentationMask));
-  __ j(not_zero, deferred->entry());
-
-  // Dispatch on the encoding: ASCII or two-byte.
-  Label ascii_string;
-  STATIC_ASSERT((kStringEncodingMask & kAsciiStringTag) != 0);
-  STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
-  __ testb(result, Immediate(kStringEncodingMask));
-  __ j(not_zero, &ascii_string, Label::kNear);
-
-  // Two-byte string.
-  // Load the two-byte character code into the result register.
-  Label done;
-  STATIC_ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
-  __ movzxwl(result, FieldOperand(string,
-                                  index,
-                                  times_2,
-                                  SeqTwoByteString::kHeaderSize));
-  __ jmp(&done, Label::kNear);
-
-  // ASCII string.
-  // Load the byte into the result register.
-  __ bind(&ascii_string);
-  __ movzxbl(result, FieldOperand(string,
-                                  index,
-                                  times_1,
-                                  SeqAsciiString::kHeaderSize));
-  __ bind(&done);
+  StringCharLoadGenerator::Generate(masm(),
+                                    ToRegister(instr->string()),
+                                    ToRegister(instr->index()),
+                                    ToRegister(instr->result()),
+                                    deferred->entry());
   __ bind(deferred->exit());
 }