Support StringCharCodeAt in hydrogen/lithium.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 2d3eac1480212d212c14678b02e8bc39f7dd98ff..f950fc1c6261c75540b97364b20462fd1128fb18 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2651,6 +2651,135 @@ void LCodeGen::DoStoreKeyedGeneric(LStoreKeyedGeneric* instr) {
 }
 
 
+void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
+  class DeferredStringCharCodeAt: public LDeferredCode {
+   public:
+    DeferredStringCharCodeAt(LCodeGen* codegen, LStringCharCodeAt* instr)
+        : LDeferredCode(codegen), instr_(instr) { }
+    virtual void Generate() { codegen()->DoDeferredStringCharCodeAt(instr_); }
+   private:
+    LStringCharCodeAt* instr_;
+  };
+
+  DeferredStringCharCodeAt* deferred = new DeferredStringCharCodeAt(this,
+                                                                    instr);
+
+  Register string = ToRegister(instr->string());
+  Register index = no_reg;
+  int const_index = -1;
+  if (instr->index()->IsConstantOperand()) {
+    const_index = ToInteger32(LConstantOperand::cast(instr->index()));
+  } else {
+    index = ToRegister(instr->index());
+  }
+  Register result = ToRegister(instr->result());
+
+  NearLabel flat_string, ascii_string, done;
+
+  // Fetch the instance type of the receiver into result register.
+  __ mov(result, FieldOperand(string, HeapObject::kMapOffset));
+  __ movzx_b(result, FieldOperand(result, Map::kInstanceTypeOffset));
+
+  // We need special handling for non-flat strings.
+  STATIC_ASSERT(kSeqStringTag == 0);
+  __ test(result, Immediate(kStringRepresentationMask));
+  __ j(zero, &flat_string);
+
+  // Handle non-flat strings.
+  __ test(result, Immediate(kIsConsStringMask));
+  __ j(zero, deferred->entry());
+
+  // 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.
+  __ cmp(FieldOperand(string, ConsString::kSecondOffset),
+         Immediate(Factory::empty_string()));
+  __ j(not_equal, deferred->entry());
+  // Get the first of the two strings and load its instance type.
+  __ mov(string, FieldOperand(string, ConsString::kFirstOffset));
+  __ mov(result, FieldOperand(string, HeapObject::kMapOffset));
+  __ movzx_b(result, FieldOperand(result, Map::kInstanceTypeOffset));
+  // If the first cons component is also non-flat, then go to runtime.
+  STATIC_ASSERT(kSeqStringTag == 0);
+  __ test(result, Immediate(kStringRepresentationMask));
+  __ j(not_zero, deferred->entry());
+
+  // Check for 1-byte or 2-byte string.
+  __ bind(&flat_string);
+  STATIC_ASSERT(kAsciiStringTag != 0);
+  __ test(result, Immediate(kStringEncodingMask));
+  __ j(not_zero, &ascii_string);
+
+  // 2-byte string.
+  // Load the 2-byte character code into the result register.
+  STATIC_ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
+  if (index.is_valid()) {
+    __ movzx_w(result, FieldOperand(string,
+                                    index, times_2,
+                                    SeqTwoByteString::kHeaderSize));
+  } else {
+    __ movzx_w(result, FieldOperand(
+        string, SeqTwoByteString::kHeaderSize + 2 * const_index));
+  }
+  __ jmp(&done);
+
+  // ASCII string.
+  // Load the byte into the result register.
+  __ bind(&ascii_string);
+  if (index.is_valid()) {
+    __ movzx_b(result, FieldOperand(string,
+                                    index, times_1,
+                                    SeqAsciiString::kHeaderSize));
+  } else {
+    __ movzx_b(result, FieldOperand(string,
+                                    SeqAsciiString::kHeaderSize + const_index));
+  }
+  __ bind(&done);
+  __ bind(deferred->exit());
+}
+
+
+void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
+  Register string = ToRegister(instr->string());
+  Register result = ToRegister(instr->result());
+
+  // TODO(3095996): Get rid of this. For now, we need to make the
+  // result register contain a valid pointer because it is already
+  // contained in the register pointer map.
+  __ Set(result, Immediate(0));
+
+  __ PushSafepointRegisters();
+  __ push(string);
+  // Push the index as a smi.
+  if (instr->index()->IsConstantOperand()) {
+    int const_index = ToInteger32(LConstantOperand::cast(instr->index()));
+    __ push(Immediate(Smi::FromInt(const_index)));
+  } else {
+    Register index = ToRegister(instr->index());
+    __ SmiTag(index);
+    __ push(index);
+  }
+  __ CallRuntimeSaveDoubles(Runtime::kStringCharCodeAt);
+  RecordSafepointWithRegisters(
+      instr->pointer_map(), 2, Safepoint::kNoDeoptimizationIndex);
+  if (FLAG_debug_code) {
+    __ AbortIfNotSmi(eax);
+  }
+  __ SmiUntag(eax);
+  __ mov(Operand(esp, EspIndexForPushAll(result) * kPointerSize), eax);
+  __ PopSafepointRegisters();
+}
+
+
+void LCodeGen::DoStringLength(LStringLength* instr) {
+  Register string = ToRegister(instr->string());
+  Register result = ToRegister(instr->result());
+  __ mov(result, FieldOperand(string, String::kLengthOffset));
+}
+
+
 void LCodeGen::DoInteger32ToDouble(LInteger32ToDouble* instr) {
   LOperand* input = instr->InputAt(0);
   ASSERT(input->IsRegister() || input->IsStackSlot());
@@ -3077,13 +3206,19 @@ void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
   InstanceType last = instr->hydrogen()->last();
 
   __ mov(temp, FieldOperand(input, HeapObject::kMapOffset));
-  __ cmpb(FieldOperand(temp, Map::kInstanceTypeOffset),
-          static_cast<int8_t>(first));
 
   // If there is only one type in the interval check for equality.
   if (first == last) {
+    __ cmpb(FieldOperand(temp, Map::kInstanceTypeOffset),
+            static_cast<int8_t>(first));
     DeoptimizeIf(not_equal, instr->environment());
-  } else {
+  } else if (first == FIRST_STRING_TYPE && last == LAST_STRING_TYPE) {
+    // String has a dedicated bit in instance type.
+    __ test_b(FieldOperand(temp, Map::kInstanceTypeOffset), kIsNotStringMask);
+    DeoptimizeIf(not_zero, instr->environment());
+  } else  {
+    __ cmpb(FieldOperand(temp, Map::kInstanceTypeOffset),
+            static_cast<int8_t>(first));
     DeoptimizeIf(below, instr->environment());
     // Omit check for the last type.
     if (last != LAST_TYPE) {