Add new HSeqStringGetChar instruction.

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 b3b0aa0ad807ae0b7efaaf25f1b96dbd4ab227a9..48bbcb1ad6a3292b0708fa96cf269e51cf97a837 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2078,6 +2078,38 @@ Operand LCodeGen::BuildSeqStringOperand(Register string,
 }
 
 
+void LCodeGen::DoSeqStringGetChar(LSeqStringGetChar* instr) {
+  String::Encoding encoding = instr->hydrogen()->encoding();
+  Register result = ToRegister(instr->result());
+  Register string = ToRegister(instr->string());
+
+  if (FLAG_debug_code) {
+    __ push(string);
+    __ mov(string, FieldOperand(string, HeapObject::kMapOffset));
+    __ movzx_b(string, FieldOperand(string, Map::kInstanceTypeOffset));
+
+    __ and_(string, Immediate(kStringRepresentationMask | kStringEncodingMask));
+    static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
+    static const uint32_t two_byte_seq_type = kSeqStringTag | kTwoByteStringTag;
+    __ cmp(string, Immediate(encoding == String::ONE_BYTE_ENCODING
+                             ? one_byte_seq_type : two_byte_seq_type));
+    __ Check(equal, kUnexpectedStringType);
+    __ pop(string);
+  }
+
+  Operand operand = BuildSeqStringOperand(string, instr->index(), encoding);
+  if (encoding == String::ONE_BYTE_ENCODING) {
+    if (result.is_byte_register()) {
+      __ mov_b(result, operand);
+    } else {
+      __ movzx_b(result, operand);
+    }
+  } else {
+    __ mov_w(result, operand);
+  }
+}
+
+
 void LCodeGen::DoSeqStringSetChar(LSeqStringSetChar* instr) {
   String::Encoding encoding = instr->hydrogen()->encoding();
   Register string = ToRegister(instr->string());