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

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 61bdf68a13a0998600954aa377b5418e4fe125a8..b28a51871e0c9a5ba641ad011b795cbc38f7f850 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -3592,86 +3592,14 @@ 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.
-  __ ldr(result, FieldMemOperand(string, HeapObject::kMapOffset));
-  __ ldrb(result, FieldMemOperand(result, Map::kInstanceTypeOffset));
-
-  // We need special handling for indirect strings.
-  Label check_sequential;
-  __ tst(result, Operand(kIsIndirectStringMask));
-  __ b(eq, &check_sequential);
-
-  // Dispatch on the indirect string shape: slice or cons.
-  Label cons_string;
-  __ tst(result, Operand(kSlicedNotConsMask));
-  __ b(eq, &cons_string);
-
-  // Handle slices.
-  Label indirect_string_loaded;
-  __ ldr(result, FieldMemOperand(string, SlicedString::kOffsetOffset));
-  __ add(index, index, Operand(result, ASR, kSmiTagSize));
-  __ ldr(string, FieldMemOperand(string, SlicedString::kParentOffset));
-  __ jmp(&indirect_string_loaded);
-
-  // 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);
-  __ ldr(result, FieldMemOperand(string, ConsString::kSecondOffset));
-  __ LoadRoot(ip, Heap::kEmptyStringRootIndex);
-  __ cmp(result, ip);
-  __ b(ne, deferred->entry());
-  // Get the first of the two strings and load its instance type.
-  __ ldr(string, FieldMemOperand(string, ConsString::kFirstOffset));
-
-  __ bind(&indirect_string_loaded);
-  __ ldr(result, FieldMemOperand(string, HeapObject::kMapOffset));
-  __ ldrb(result, FieldMemOperand(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);
-  __ tst(result, Operand(kStringRepresentationMask));
-  __ b(ne, deferred->entry());
-
-  // Dispatch on the encoding: ASCII or two-byte.
-  Label ascii_string;
-  STATIC_ASSERT((kStringEncodingMask & kAsciiStringTag) != 0);
-  STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
-  __ tst(result, Operand(kStringEncodingMask));
-  __ b(ne, &ascii_string);
-
-  // Two-byte string.
-  // Load the two-byte character code into the result register.
-  Label done;
-  __ add(result,
-         string,
-         Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  __ ldrh(result, MemOperand(result, index, LSL, 1));
-  __ jmp(&done);
-
-  // ASCII string.
-  // Load the byte into the result register.
-  __ bind(&ascii_string);
-  __ add(result,
-         string,
-         Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  __ ldrb(result, MemOperand(result, index));
-
-  __ bind(&done);
+  StringCharLoadGenerator::Generate(masm(),
+                                    ToRegister(instr->string()),
+                                    ToRegister(instr->index()),
+                                    ToRegister(instr->result()),
+                                    deferred->entry());
   __ bind(deferred->exit());
 }