Crankshaft support for StringCharFromCode.

src/hydrogen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3685 matching lines @@
     AddInstruction(new HCheckInstanceType(array, JS_ARRAY_TYPE, JS_ARRAY_TYPE));
     instr = new HJSArrayLength(array);
 
   } else if (expr->IsStringLength()) {
     HValue* string = Pop();
     AddInstruction(new HCheckNonSmi(string));
     AddInstruction(new HCheckInstanceType(string,
                                           FIRST_STRING_TYPE,
                                           LAST_STRING_TYPE));
     instr = new HStringLength(string);
+  } else if (expr->IsStringAccess()) {
+    VISIT_FOR_VALUE(expr->key());
+    HValue* index = Pop();
+    HValue* string = Pop();
+    HStringCharCodeAt* char_code = BuildStringCharCodeAt(string, index);
+    AddInstruction(char_code);
+    instr = new HStringCharFromCode(char_code);
 
   } else if (expr->IsFunctionPrototype()) {
     HValue* function = Pop();
     AddInstruction(new HCheckNonSmi(function));
     instr = new HLoadFunctionPrototype(function);
 
   } else if (expr->key()->IsPropertyName()) {
     Handle<String> name = expr->key()->AsLiteral()->AsPropertyName();
     ZoneMapList* types = expr->GetReceiverTypes();
 
@@ skipping 360 matching lines @@
                                              HValue* receiver,
                                              Handle<Map> receiver_map,
                                              CheckType check_type) {
   ASSERT(check_type != RECEIVER_MAP_CHECK || !receiver_map.is_null());
   // Try to inline calls like Math.* as operations in the calling function.
   if (!expr->target()->shared()->HasBuiltinFunctionId()) return false;
   BuiltinFunctionId id = expr->target()->shared()->builtin_function_id();
   int argument_count = expr->arguments()->length() + 1;  // Plus receiver.
   switch (id) {
     case kStringCharCodeAt:
+    case kStringCharAt:
       if (argument_count == 2 && check_type == STRING_CHECK) {
         HValue* index = Pop();
         HValue* string = Pop();
         ASSERT(!expr->holder().is_null());
         AddInstruction(new HCheckPrototypeMaps(
             oracle()->GetPrototypeForPrimitiveCheck(STRING_CHECK),
             expr->holder()));
-        HStringCharCodeAt* result = BuildStringCharCodeAt(string, index);
+        HStringCharCodeAt* char_code = BuildStringCharCodeAt(string, index);
+        if (id == kStringCharCodeAt) {
+          ast_context()->ReturnInstruction(char_code, expr->id());
+          return true;
+        }

[fschneider, 2011/03/14 11:34:17]

You could save a line by writing:
if (id == kStringCharCodeAt) {
  ast_context()->ReturnInstruction(char_code, expr->id());
} else {
  ...
}
return true;

[Vitaly Repeshko, 2011/03/14 14:15:50]

This would replace "return true" with "} else {". Sorry, I'm a huge fan of early
returns :)

+        AddInstruction(char_code);
+        HStringCharFromCode* result = new HStringCharFromCode(char_code);
         ast_context()->ReturnInstruction(result, expr->id());
         return true;
       }
       break;
     case kMathRound:
     case kMathFloor:
     case kMathAbs:
     case kMathSqrt:
     case kMathLog:
     case kMathSin:
@@ skipping 1065 matching lines @@
   VISIT_FOR_VALUE(call->arguments()->at(1));
   HValue* index = Pop();
   HValue* string = Pop();
   HStringCharCodeAt* result = BuildStringCharCodeAt(string, index);
   ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 // Fast support for string.charAt(n) and string[n].
 void HGraphBuilder::GenerateStringCharFromCode(CallRuntime* call) {
-  BAILOUT("inlined runtime function: StringCharFromCode");
+  ASSERT(call->arguments()->length() == 1);
+  VISIT_FOR_VALUE(call->arguments()->at(0));
+  HValue* char_code = Pop();
+  HStringCharFromCode* result = new HStringCharFromCode(char_code);
+  ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 // Fast support for string.charAt(n) and string[n].
 void HGraphBuilder::GenerateStringCharAt(CallRuntime* call) {
-  ASSERT_EQ(2, call->arguments()->length());
-  VisitArgumentList(call->arguments());
-  CHECK_BAILOUT;
-  HContext* context = new HContext;
-  AddInstruction(context);
-  HCallStub* result = new HCallStub(context, CodeStub::StringCharAt, 2);
-  Drop(2);
+  ASSERT(call->arguments()->length() == 2);
+  VISIT_FOR_VALUE(call->arguments()->at(0));
+  VISIT_FOR_VALUE(call->arguments()->at(1));
+  HValue* index = Pop();
+  HValue* string = Pop();
+  HStringCharCodeAt* char_code = BuildStringCharCodeAt(string, index);
+  AddInstruction(char_code);
+  HStringCharFromCode* result = new HStringCharFromCode(char_code);
   ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 // Fast support for object equality testing.
 void HGraphBuilder::GenerateObjectEquals(CallRuntime* call) {
   ASSERT(call->arguments()->length() == 2);
   VISIT_FOR_VALUE(call->arguments()->at(0));
   VISIT_FOR_VALUE(call->arguments()->at(1));
   HValue* right = Pop();
@@ skipping 702 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal