Initial implementation of fast path operation for bitwise OR.

src/fast-codegen.cc

 // Copyright 2010 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 275 matching lines @@
   Visit(expr->value());
 }
 
 
 void FastCodeGenSyntaxChecker::VisitThrow(Throw* expr) {
   BAILOUT("Throw");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitProperty(Property* expr) {
-  BAILOUT("Property");
+  // We support named this property references.
+  VariableProxy* proxy = expr->obj()->AsVariableProxy();
+  if (proxy == NULL || !proxy->var()->is_this()) {
+    BAILOUT("Non-this-property reference");
+  }
+  if (!expr->key()->IsPropertyName()) {
+    BAILOUT("Non-named-property reference");
+  }
+
+  // We will only specialize for fields on the object itself.
+  // Expression::IsPropertyName implies that the name is a literal
+  // symbol but we do not assume that.
+  Literal* key = expr->key()->AsLiteral();
+  if (key != NULL && key->handle()->IsString()) {
+    Handle<Object> receiver = info()->receiver();
+    Handle<String> name = Handle<String>::cast(key->handle());
+    LookupResult lookup;
+    receiver->Lookup(*name, &lookup);
+    if (lookup.holder() != *receiver) BAILOUT("Non-own property reference");
+    if (!lookup.type() == FIELD) BAILOUT("Non-field property reference");
+  } else {
+    UNREACHABLE();
+    BAILOUT("Unexpected non-string-literal property key");
+  }
 }
 
 
 void FastCodeGenSyntaxChecker::VisitCall(Call* expr) {
   BAILOUT("Call");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitCallNew(CallNew* expr) {
   BAILOUT("CallNew");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitCallRuntime(CallRuntime* expr) {
   BAILOUT("CallRuntime");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitUnaryOperation(UnaryOperation* expr) {
   BAILOUT("UnaryOperation");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitCountOperation(CountOperation* expr) {
   BAILOUT("CountOperation");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitBinaryOperation(BinaryOperation* expr) {
-  BAILOUT("BinaryOperation");
+  // We support bitwise OR.
+  switch (expr->op()) {
+    case Token::COMMA:
+      BAILOUT("BinaryOperation COMMA");
+    case Token::OR:
+      BAILOUT("BinaryOperation OR");
+    case Token::AND:
+      BAILOUT("BinaryOperation AND");
+
+    case Token::BIT_OR:
+      // We support expressions nested on the left because they only require
+      // a pair of registers to keep all intermediate values in registers
+      // (i.e., the expression stack has height no more than two).
+      if (!expr->right()->IsLeaf()) BAILOUT("expression nested on right");
+      Visit(expr->left());
+      CHECK_BAILOUT;
+      Visit(expr->right());
+      break;
+
+    case Token::BIT_XOR:
+      BAILOUT("BinaryOperation BIT_XOR");
+    case Token::BIT_AND:
+      BAILOUT("BinaryOperation BIT_AND");
+    case Token::SHL:
+      BAILOUT("BinaryOperation SHL");
+    case Token::SAR:
+      BAILOUT("BinaryOperation SAR");
+    case Token::SHR:
+      BAILOUT("BinaryOperation SHR");
+    case Token::ADD:
+      BAILOUT("BinaryOperation ADD");
+    case Token::SUB:
+      BAILOUT("BinaryOperation SUB");
+    case Token::MUL:
+      BAILOUT("BinaryOperation MUL");
+    case Token::DIV:
+      BAILOUT("BinaryOperation DIV");
+    case Token::MOD:
+      BAILOUT("BinaryOperation MOD");
+    default:
+      UNREACHABLE();
+  }
 }
 
 
 void FastCodeGenSyntaxChecker::VisitCompareOperation(CompareOperation* expr) {
   BAILOUT("CompareOperation");
 }
 
 
 void FastCodeGenSyntaxChecker::VisitThisFunction(ThisFunction* expr) {
   BAILOUT("ThisFunction");
@@ skipping 145 matching lines @@
 }
 
 
 void FastCodeGenerator::VisitSlot(Slot* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
   ASSERT(expr->var()->is_global() && !expr->var()->is_this());
-  Comment cmnt(masm(), ";; Global");
-  if (FLAG_print_ir) {
-    SmartPointer<char> name = expr->name()->ToCString();
-    PrintF("%d: t%d = Global(%s)\n", expr->num(), expr->num(), *name);
-  }
-
   // Check if we can compile a global variable load directly from the cell.
   ASSERT(info()->has_global_object());
   LookupResult lookup;
   info()->global_object()->Lookup(*expr->name(), &lookup);
   // We only support DontDelete properties for now.
   ASSERT(lookup.IsValid());
   ASSERT(lookup.IsDontDelete());
   Handle<Object> cell(info()->global_object()->GetPropertyCell(&lookup));
-  EmitGlobalVariableLoad(cell);
+
+  // Global variable lookups do not have side effects, so we do not need to
+  // emit code if we are in an effect context.
+  if (!destination().is(no_reg)) {
+    Comment cmnt(masm(), ";; Global");
+    if (FLAG_print_ir) {
+      SmartPointer<char> name = expr->name()->ToCString();
+      PrintF("%d: t%d = Global(%s)\n", expr->num(), expr->num(), *name);
+    }
+    EmitGlobalVariableLoad(cell);
+  }
 }
 
 
 void FastCodeGenerator::VisitLiteral(Literal* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitCatchExtensionObject(CatchExtensionObject* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitAssignment(Assignment* expr) {
-  // Known to be a simple this property assignment.
-  Visit(expr->value());
+  // Known to be a simple this property assignment.  Effectively a unary
+  // operation.
+  { Register my_destination = destination();
+    set_destination(accumulator0());
+    Visit(expr->value());
+    set_destination(my_destination);
+  }
 
   Property* prop = expr->target()->AsProperty();
   ASSERT_NOT_NULL(prop);
   ASSERT_NOT_NULL(prop->obj()->AsVariableProxy());
   ASSERT(prop->obj()->AsVariableProxy()->var()->is_this());
   ASSERT(prop->key()->IsPropertyName());
   Handle<String> name =
       Handle<String>::cast(prop->key()->AsLiteral()->handle());
 
-  Comment cmnt(masm(), ";; Store(this)");
+  Comment cmnt(masm(), ";; Store to this");
   if (FLAG_print_ir) {
     SmartPointer<char> name_string = name->ToCString();
-    PrintF("%d: t%d = Store(this, \"%s\", t%d)\n",
-           expr->num(), expr->num(), *name_string, expr->value()->num());
+    PrintF("%d: ", expr->num());
+    if (!destination().is(no_reg)) PrintF("t%d = ", expr->num());
+    PrintF("Store(this, \"%s\", t%d)\n", *name_string, expr->value()->num());
   }
 
   EmitThisPropertyStore(name);
 }
 
 
 void FastCodeGenerator::VisitThrow(Throw* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitProperty(Property* expr) {
-  UNREACHABLE();
+  ASSERT_NOT_NULL(expr->obj()->AsVariableProxy());
+  ASSERT(expr->obj()->AsVariableProxy()->var()->is_this());
+  ASSERT(expr->key()->IsPropertyName());
+  if (!destination().is(no_reg)) {
+    Handle<String> name =
+        Handle<String>::cast(expr->key()->AsLiteral()->handle());
+
+    Comment cmnt(masm(), ";; Load from this");
+    if (FLAG_print_ir) {
+      SmartPointer<char> name_string = name->ToCString();
+      PrintF("%d: t%d = Load(this, \"%s\")\n",
+             expr->num(), expr->num(), *name_string);
+    }
+    EmitThisPropertyLoad(name);
+  }
 }
 
 
 void FastCodeGenerator::VisitCall(Call* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitCallNew(CallNew* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitCountOperation(CountOperation* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitBinaryOperation(BinaryOperation* expr) {
-  UNREACHABLE();
+  // We support limited binary operations: bitwise OR only allowed to be
+  // nested on the left.
+  ASSERT(expr->op() == Token::BIT_OR);
+  ASSERT(expr->right()->IsLeaf());
+
+  { Register my_destination = destination();
+    set_destination(accumulator1());
+    Visit(expr->left());
+    set_destination(accumulator0());
+    Visit(expr->right());
+    set_destination(my_destination);
+  }
+
+  Comment cmnt(masm(), ";; BIT_OR");
+  if (FLAG_print_ir) {
+    PrintF("%d: ", expr->num());
+    if (!destination().is(no_reg)) PrintF("t%d = ", expr->num());
+    PrintF("BIT_OR(t%d, t%d)\n", expr->left()->num(), expr->right()->num());
+  }
+  EmitBitOr();
 }
 
 
 void FastCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   UNREACHABLE();
 }
 
 #undef __
 
 
 } }  // namespace v8::internal