Increase coverage of global loads in optimized code...

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 1943 matching lines @@
 
 FunctionState::~FunctionState() {
   delete test_context_;
   owner_->set_function_state(outer_);
 }
 
 
 // Implementation of utility classes to represent an expression's context in
 // the AST.
 AstContext::AstContext(HGraphBuilder* owner, Expression::Context kind)
-    : owner_(owner), kind_(kind), outer_(owner->ast_context()) {
+    : owner_(owner),
+      kind_(kind),
+      outer_(owner->ast_context()),
+      for_typeof_(false) {
   owner->set_ast_context(this);  // Push.
 #ifdef DEBUG
   original_length_ = owner->environment()->length();
 #endif
 }
 
 
 AstContext::~AstContext() {
   owner_->set_ast_context(outer_);  // Pop.
 }
@@ skipping 123 matching lines @@
   Visit(expr);
 }
 
 
 void HGraphBuilder::VisitForValue(Expression* expr) {
   ValueContext for_value(this);
   Visit(expr);
 }
 
 
+void HGraphBuilder::VisitForTypeOf(Expression* expr) {
+  ValueContext for_value(this);
+  for_value.set_for_typeof(true);
+  Visit(expr);
+}
+
+
+
 void HGraphBuilder::VisitForControl(Expression* expr,
                                     HBasicBlock* true_block,
                                     HBasicBlock* false_block) {
   TestContext for_test(this, true_block, false_block);
   Visit(expr);
 }
 
 
 void HGraphBuilder::VisitArgument(Expression* expr) {
   VISIT_FOR_VALUE(expr);
@@ skipping 672 matching lines @@
   CHECK_BAILOUT;
 
   if (!ast_context()->IsTest()) {
     HBasicBlock* join = CreateJoin(other, current_block(), expr->id());
     set_current_block(join);
     if (!ast_context()->IsEffect()) ast_context()->ReturnValue(Pop());
   }
 }
 
 
-void HGraphBuilder::LookupGlobalPropertyCell(Variable* var,
-                                             LookupResult* lookup,
-                                             bool is_store) {
+HGraphBuilder::GlobalPropertyAccess HGraphBuilder::LookupGlobalProperty(
+    Variable* var, LookupResult* lookup, bool is_store) {
   if (var->is_this()) {
-    BAILOUT("global this reference");
+    return kUseGeneric;

[fschneider, 2011/03/16 10:28:18]

I'd move this into the same line as the if-statement, if it fits. (also in the
ones below)

[Søren Thygesen Gjesse, 2011/03/17 07:52:27]

Done.

   }
   if (!info()->has_global_object()) {
-    BAILOUT("no global object to optimize VariableProxy");
+    return kUseGeneric;
   }
   Handle<GlobalObject> global(info()->global_object());
   global->Lookup(*var->name(), lookup);
   if (!lookup->IsProperty()) {
-    BAILOUT("global variable cell not yet introduced");
+    return kUseGeneric;
   }
   if (lookup->type() != NORMAL) {
-    BAILOUT("global variable has accessors");
+    return kUseGeneric;
   }
   if (is_store && lookup->IsReadOnly()) {
-    BAILOUT("read-only global variable");
+    return kUseGeneric;
   }
   if (lookup->holder() != *global) {
-    BAILOUT("global property on prototype of global object");
+    return kUseGeneric;
   }
+
+  return kUseCell;
 }
 
 
 HValue* HGraphBuilder::BuildContextChainWalk(Variable* var) {
   ASSERT(var->IsContextSlot());
   HInstruction* context = new HContext;
   AddInstruction(context);
   int length = info()->scope()->ContextChainLength(var->scope());
   while (length-- > 0) {
     context = new HOuterContext(context);
@@ skipping 15 matching lines @@
   } else if (variable->IsContextSlot()) {
     if (variable->mode() == Variable::CONST) {
       BAILOUT("reference to const context slot");
     }
     HValue* context = BuildContextChainWalk(variable);
     int index = variable->AsSlot()->index();
     HLoadContextSlot* instr = new HLoadContextSlot(context, index);
     ast_context()->ReturnInstruction(instr, expr->id());
   } else if (variable->is_global()) {
     LookupResult lookup;
-    LookupGlobalPropertyCell(variable, &lookup, false);
-    CHECK_BAILOUT;
+    GlobalPropertyAccess type = LookupGlobalProperty(variable, &lookup, false);
 
-    Handle<GlobalObject> global(info()->global_object());
-    // TODO(3039103): Handle global property load through an IC call when access
-    // checks are enabled.
-    if (global->IsAccessCheckNeeded()) {
-      BAILOUT("global object requires access check");
+    if (type == kUseCell &&
+        info()->global_object()->IsAccessCheckNeeded()) {
+      type = kUseGeneric;
     }
-    Handle<JSGlobalPropertyCell> cell(global->GetPropertyCell(&lookup));
-    bool check_hole = !lookup.IsDontDelete() || lookup.IsReadOnly();
-    HLoadGlobal* instr = new HLoadGlobal(cell, check_hole);
-    ast_context()->ReturnInstruction(instr, expr->id());
+
+    if (type == kUseCell) {
+      Handle<GlobalObject> global(info()->global_object());
+      Handle<JSGlobalPropertyCell> cell(global->GetPropertyCell(&lookup));
+      bool check_hole = !lookup.IsDontDelete() || lookup.IsReadOnly();
+      HLoadGlobalCell* instr = new HLoadGlobalCell(cell, check_hole);
+      ast_context()->ReturnInstruction(instr, expr->id());
+    } else {
+      HContext* context = new HContext;
+      AddInstruction(context);
+      HLoadGlobalGeneric* instr =
+          new HLoadGlobalGeneric(
+              context, variable->name(), ast_context()->is_for_typeof());
+      ast_context()->ReturnInstruction(instr, expr->id());
+    }
   } else {
     BAILOUT("reference to a variable which requires dynamic lookup");
   }
 }
 
 
 void HGraphBuilder::VisitLiteral(Literal* expr) {
   HConstant* instr = new HConstant(expr->handle(), Representation::Tagged());
   ast_context()->ReturnInstruction(instr, expr->id());
 }
@@ skipping 336 matching lines @@
 
 
 // Because not every expression has a position and there is not common
 // superclass of Assignment and CountOperation, we cannot just pass the
 // owning expression instead of position and ast_id separately.
 void HGraphBuilder::HandleGlobalVariableAssignment(Variable* var,
                                                    HValue* value,
                                                    int position,
                                                    int ast_id) {
   LookupResult lookup;
-  LookupGlobalPropertyCell(var, &lookup, true);
-  CHECK_BAILOUT;
-
-  bool check_hole = !lookup.IsDontDelete() || lookup.IsReadOnly();
-  Handle<GlobalObject> global(info()->global_object());
-  Handle<JSGlobalPropertyCell> cell(global->GetPropertyCell(&lookup));
-  HInstruction* instr = new HStoreGlobal(value, cell, check_hole);
-  instr->set_position(position);
-  AddInstruction(instr);
-  if (instr->HasSideEffects()) AddSimulate(ast_id);
+  GlobalPropertyAccess type = LookupGlobalProperty(var, &lookup, true);
+  if (type == kUseCell) {
+    bool check_hole = !lookup.IsDontDelete() || lookup.IsReadOnly();
+    Handle<GlobalObject> global(info()->global_object());
+    Handle<JSGlobalPropertyCell> cell(global->GetPropertyCell(&lookup));
+    HInstruction* instr = new HStoreGlobal(value, cell, check_hole);
+    instr->set_position(position);
+    AddInstruction(instr);
+    if (instr->HasSideEffects()) AddSimulate(ast_id);
+  } else {
+    BAILOUT("global store only supported for cells");
+  }
 }
 
 
 void HGraphBuilder::HandleCompoundAssignment(Assignment* expr) {
   Expression* target = expr->target();
   VariableProxy* proxy = target->AsVariableProxy();
   Variable* var = proxy->AsVariable();
   Property* prop = target->AsProperty();
   ASSERT(var == NULL || prop == NULL);
 
@@ skipping 1074 matching lines @@
     if (!global_call) {
       ++argument_count;
       VISIT_FOR_VALUE(expr->expression());
     }
 
     if (global_call) {
       bool known_global_function = false;
       // If there is a global property cell for the name at compile time and
       // access check is not enabled we assume that the function will not change
       // and generate optimized code for calling the function.
-      if (info()->has_global_object() &&
+      LookupResult lookup;
+      GlobalPropertyAccess type = LookupGlobalProperty(var, &lookup, false);
+      if (type == kUseCell &&
           !info()->global_object()->IsAccessCheckNeeded()) {
         Handle<GlobalObject> global(info()->global_object());
-        known_global_function = expr->ComputeGlobalTarget(global, var->name());
+        known_global_function = expr->ComputeGlobalTarget(global, lookup);
       }
       if (known_global_function) {
         // Push the global object instead of the global receiver because
         // code generated by the full code generator expects it.
         HContext* context = new HContext;
         HGlobalObject* global_object = new HGlobalObject(context);
         AddInstruction(context);
         PushAndAdd(global_object);
         VisitExpressions(expr->arguments());
         CHECK_BAILOUT;
@@ skipping 198 matching lines @@
         break;
       case Token::SUB:
         instr = new HMul(graph_->GetConstantMinus1(), value);
         break;
       default:
         UNREACHABLE();
         break;
     }
     ast_context()->ReturnInstruction(instr, expr->id());
   } else if (op == Token::TYPEOF) {
-    VISIT_FOR_VALUE(expr->expression());
+    VisitForTypeOf(expr);
+    if (HasStackOverflow()) return;
     HValue* value = Pop();
     ast_context()->ReturnInstruction(new HTypeof(value), expr->id());
   } else {
     BAILOUT("Value: unsupported unary operation");
   }
 }
 
 
 void HGraphBuilder::VisitIncrementOperation(IncrementOperation* expr) {
   // IncrementOperation is never visited by the visitor. It only
@@ skipping 364 matching lines @@
     ast_context()->ReturnInstruction(instr, expr->id());
     return;
   }
 
   // Check for the pattern: typeof <expression> == <string literal>.
   UnaryOperation* left_unary = expr->left()->AsUnaryOperation();
   Literal* right_literal = expr->right()->AsLiteral();
   if ((expr->op() == Token::EQ || expr->op() == Token::EQ_STRICT) &&
       left_unary != NULL && left_unary->op() == Token::TYPEOF &&
       right_literal != NULL && right_literal->handle()->IsString()) {
-    VISIT_FOR_VALUE(left_unary->expression());
+    VisitForTypeOf(expr);
+    if (HasStackOverflow()) return;
     HValue* left = Pop();
     HInstruction* instr = new HTypeofIs(left,
         Handle<String>::cast(right_literal->handle()));
     instr->set_position(expr->position());
     ast_context()->ReturnInstruction(instr, expr->id());
     return;
   }
 
   VISIT_FOR_VALUE(expr->left());
   VISIT_FOR_VALUE(expr->right());
@@ skipping 976 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal