Fix a problem with const initialization in the top-level code generator.

When initializing the special local variable containing the reference to the enclosing 
function in named functions we now (correctly) emit an INIT_CONST instead of INIT_VAR,
and we correctly bail out in the top-level code generator.

Also part of this change is adding missing statement position information 
for some statements in the top-level code generator.

Review URL: http://codereview.chromium.org/536029

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3587 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/codegen-arm.cc

@@ -263,6 +263,13 @@ void CodeGenerator::GenCode(FunctionLiteral* fun) {
       frame_->Drop();  // Value is no longer needed.
     }
 
+    // Initialize ThisFunction reference if present.
+    if (scope_->is_function_scope() && scope_->function() != NULL) {
+      __ mov(ip, Operand(Factory::the_hole_value()));
+      frame_->EmitPush(ip);
+      StoreToSlot(scope_->function()->slot(), NOT_CONST_INIT);
+    }
+
     // Generate code to 'execute' declarations and initialize functions
     // (source elements). In case of an illegal redeclaration we need to
     // handle that instead of processing the declarations.
@@ -2446,6 +2453,87 @@ void CodeGenerator::LoadFromSlot(Slot* slot, TypeofState typeof_state) {
 }
 
 
+void CodeGenerator::StoreToSlot(Slot* slot, InitState init_state) {
+  ASSERT(slot != NULL);
+  if (slot->type() == Slot::LOOKUP) {
+    ASSERT(slot->var()->is_dynamic());
+
+    // For now, just do a runtime call.
+    frame_->EmitPush(cp);
+    __ mov(r0, Operand(slot->var()->name()));
+    frame_->EmitPush(r0);
+
+    if (init_state == CONST_INIT) {
+      // Same as the case for a normal store, but ignores attribute
+      // (e.g. READ_ONLY) of context slot so that we can initialize
+      // const properties (introduced via eval("const foo = (some
+      // expr);")). Also, uses the current function context instead of
+      // the top context.
+      //
+      // Note that we must declare the foo upon entry of eval(), via a
+      // context slot declaration, but we cannot initialize it at the
+      // same time, because the const declaration may be at the end of
+      // the eval code (sigh...) and the const variable may have been
+      // used before (where its value is 'undefined'). Thus, we can only
+      // do the initialization when we actually encounter the expression
+      // and when the expression operands are defined and valid, and
+      // thus we need the split into 2 operations: declaration of the
+      // context slot followed by initialization.
+      frame_->CallRuntime(Runtime::kInitializeConstContextSlot, 3);
+    } else {
+      frame_->CallRuntime(Runtime::kStoreContextSlot, 3);
+    }
+    // Storing a variable must keep the (new) value on the expression
+    // stack. This is necessary for compiling assignment expressions.
+    frame_->EmitPush(r0);
+
+  } else {
+    ASSERT(!slot->var()->is_dynamic());
+
+    JumpTarget exit;
+    if (init_state == CONST_INIT) {
+      ASSERT(slot->var()->mode() == Variable::CONST);
+      // Only the first const initialization must be executed (the slot
+      // still contains 'the hole' value). When the assignment is
+      // executed, the code is identical to a normal store (see below).
+      Comment cmnt(masm_, "[ Init const");
+      __ ldr(r2, SlotOperand(slot, r2));
+      __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
+      __ cmp(r2, ip);
+      exit.Branch(ne);
+    }
+
+    // We must execute the store.  Storing a variable must keep the
+    // (new) value on the stack. This is necessary for compiling
+    // assignment expressions.
+    //
+    // Note: We will reach here even with slot->var()->mode() ==
+    // Variable::CONST because of const declarations which will
+    // initialize consts to 'the hole' value and by doing so, end up
+    // calling this code.  r2 may be loaded with context; used below in
+    // RecordWrite.
+    frame_->EmitPop(r0);
+    __ str(r0, SlotOperand(slot, r2));
+    frame_->EmitPush(r0);
+    if (slot->type() == Slot::CONTEXT) {
+      // Skip write barrier if the written value is a smi.
+      __ tst(r0, Operand(kSmiTagMask));
+      exit.Branch(eq);
+      // r2 is loaded with context when calling SlotOperand above.
+      int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
+      __ mov(r3, Operand(offset));
+      __ RecordWrite(r2, r3, r1);
+    }
+    // If we definitely did not jump over the assignment, we do not need
+    // to bind the exit label.  Doing so can defeat peephole
+    // optimization.
+    if (init_state == CONST_INIT || slot->type() == Slot::CONTEXT) {
+      exit.Bind();
+    }
+  }
+}
+
+
 void CodeGenerator::LoadFromGlobalSlotCheckExtensions(Slot* slot,
                                                       TypeofState typeof_state,
                                                       Register tmp,
@@ -4262,83 +4350,7 @@ void Reference::SetValue(InitState init_state) {
     case SLOT: {
       Comment cmnt(masm, "[ Store to Slot");
       Slot* slot = expression_->AsVariableProxy()->AsVariable()->slot();
-      ASSERT(slot != NULL);
-      if (slot->type() == Slot::LOOKUP) {
-        ASSERT(slot->var()->is_dynamic());
-
-        // For now, just do a runtime call.
-        frame->EmitPush(cp);
-        __ mov(r0, Operand(slot->var()->name()));
-        frame->EmitPush(r0);
-
-        if (init_state == CONST_INIT) {
-          // Same as the case for a normal store, but ignores attribute
-          // (e.g. READ_ONLY) of context slot so that we can initialize
-          // const properties (introduced via eval("const foo = (some
-          // expr);")). Also, uses the current function context instead of
-          // the top context.
-          //
-          // Note that we must declare the foo upon entry of eval(), via a
-          // context slot declaration, but we cannot initialize it at the
-          // same time, because the const declaration may be at the end of
-          // the eval code (sigh...) and the const variable may have been
-          // used before (where its value is 'undefined'). Thus, we can only
-          // do the initialization when we actually encounter the expression
-          // and when the expression operands are defined and valid, and
-          // thus we need the split into 2 operations: declaration of the
-          // context slot followed by initialization.
-          frame->CallRuntime(Runtime::kInitializeConstContextSlot, 3);
-        } else {
-          frame->CallRuntime(Runtime::kStoreContextSlot, 3);
-        }
-        // Storing a variable must keep the (new) value on the expression
-        // stack. This is necessary for compiling assignment expressions.
-        frame->EmitPush(r0);
-
-      } else {
-        ASSERT(!slot->var()->is_dynamic());
-
-        JumpTarget exit;
-        if (init_state == CONST_INIT) {
-          ASSERT(slot->var()->mode() == Variable::CONST);
-          // Only the first const initialization must be executed (the slot
-          // still contains 'the hole' value). When the assignment is
-          // executed, the code is identical to a normal store (see below).
-          Comment cmnt(masm, "[ Init const");
-          __ ldr(r2, cgen_->SlotOperand(slot, r2));
-          __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
-          __ cmp(r2, ip);
-          exit.Branch(ne);
-        }
-
-        // We must execute the store.  Storing a variable must keep the
-        // (new) value on the stack. This is necessary for compiling
-        // assignment expressions.
-        //
-        // Note: We will reach here even with slot->var()->mode() ==
-        // Variable::CONST because of const declarations which will
-        // initialize consts to 'the hole' value and by doing so, end up
-        // calling this code.  r2 may be loaded with context; used below in
-        // RecordWrite.
-        frame->EmitPop(r0);
-        __ str(r0, cgen_->SlotOperand(slot, r2));
-        frame->EmitPush(r0);
-        if (slot->type() == Slot::CONTEXT) {
-          // Skip write barrier if the written value is a smi.
-          __ tst(r0, Operand(kSmiTagMask));
-          exit.Branch(eq);
-          // r2 is loaded with context when calling SlotOperand above.
-          int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
-          __ mov(r3, Operand(offset));
-          __ RecordWrite(r2, r3, r1);
-        }
-        // If we definitely did not jump over the assignment, we do not need
-        // to bind the exit label.  Doing so can defeat peephole
-        // optimization.
-        if (init_state == CONST_INIT || slot->type() == Slot::CONTEXT) {
-          exit.Bind();
-        }
-      }
+      cgen_->StoreToSlot(slot, init_state);
       break;
     }
 

src/arm/codegen-arm.h

@@ -272,6 +272,9 @@ class CodeGenerator: public AstVisitor {
 
   // Read a value from a slot and leave it on top of the expression stack.
   void LoadFromSlot(Slot* slot, TypeofState typeof_state);
+  // Store the value on top of the stack to a slot.
+  void StoreToSlot(Slot* slot, InitState init_state);
+
   void LoadFromGlobalSlotCheckExtensions(Slot* slot,
                                          TypeofState typeof_state,
                                          Register tmp,

src/compiler.cc

@@ -888,6 +888,9 @@ void CodeGenSelector::VisitAssignment(Assignment* expr) {
   Property* prop = expr->target()->AsProperty();
   ASSERT(var == NULL || prop == NULL);
   if (var != NULL) {
+    if (var->mode() == Variable::CONST) {
+      BAILOUT("Assignment to const");
+    }
     // All global variables are supported.
     if (!var->is_global()) {
       ASSERT(var->slot() != NULL);

src/fast-codegen.cc

@@ -288,6 +288,7 @@ void FastCodeGenerator::VisitEmptyStatement(EmptyStatement* stmt) {
 
 void FastCodeGenerator::VisitIfStatement(IfStatement* stmt) {
   Comment cmnt(masm_, "[ IfStatement");
+  SetStatementPosition(stmt);
   // Expressions cannot recursively enter statements, there are no labels in
   // the state.
   ASSERT_EQ(NULL, true_label_);
@@ -315,6 +316,7 @@ void FastCodeGenerator::VisitIfStatement(IfStatement* stmt) {
 
 void FastCodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
   Comment cmnt(masm_,  "[ ContinueStatement");
+  SetStatementPosition(stmt);
   NestedStatement* current = nesting_stack_;
   int stack_depth = 0;
   while (!current->IsContinueTarget(stmt->target())) {
@@ -330,6 +332,7 @@ void FastCodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
 
 void FastCodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
   Comment cmnt(masm_,  "[ BreakStatement");
+  SetStatementPosition(stmt);
   NestedStatement* current = nesting_stack_;
   int stack_depth = 0;
   while (!current->IsBreakTarget(stmt->target())) {
@@ -345,6 +348,7 @@ void FastCodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
 
 void FastCodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
   Comment cmnt(masm_, "[ ReturnStatement");
+  SetStatementPosition(stmt);
   Expression* expr = stmt->expression();
   // Complete the statement based on the type of the subexpression.
   if (expr->AsLiteral() != NULL) {
@@ -406,6 +410,7 @@ void FastCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
 
 void FastCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
   Comment cmnt(masm_, "[ DoWhileStatement");
+  SetStatementPosition(stmt);
   Label body, stack_limit_hit, stack_check_success;
 
   Iteration loop_statement(this, stmt);
@@ -443,6 +448,7 @@ void FastCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
 
 void FastCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
   Comment cmnt(masm_, "[ WhileStatement");
+  SetStatementPosition(stmt);
   Label body, stack_limit_hit, stack_check_success;
 
   Iteration loop_statement(this, stmt);

src/ia32/codegen-ia32.cc

@@ -251,6 +251,12 @@ void CodeGenerator::GenCode(FunctionLiteral* fun) {
       StoreArgumentsObject(true);
     }
 
+    // Initialize ThisFunction reference if present.
+    if (scope_->is_function_scope() && scope_->function() != NULL) {
+      frame_->Push(Factory::the_hole_value());
+      StoreToSlot(scope_->function()->slot(), NOT_CONST_INIT);
+    }
+
     // Generate code to 'execute' declarations and initialize functions
     // (source elements). In case of an illegal redeclaration we need to
     // handle that instead of processing the declarations.

src/parser.cc

@@ -3598,7 +3598,7 @@ FunctionLiteral* Parser::ParseFunctionLiteral(Handle<String> var_name,
           top_scope_->NewUnresolved(function_name, inside_with());
       fproxy->BindTo(fvar);
       body.Add(new ExpressionStatement(
-                   new Assignment(Token::INIT_VAR, fproxy,
+                   new Assignment(Token::INIT_CONST, fproxy,
                                   NEW(ThisFunction()),
                                   RelocInfo::kNoPosition)));
     }

src/x64/codegen-x64.cc

@@ -393,6 +393,12 @@ void CodeGenerator::GenCode(FunctionLiteral* function) {
       StoreArgumentsObject(true);
     }
 
+    // Initialize ThisFunction reference if present.
+    if (scope_->is_function_scope() && scope_->function() != NULL) {
+      frame_->Push(Factory::the_hole_value());
+      StoreToSlot(scope_->function()->slot(), NOT_CONST_INIT);
+    }
+
     // Generate code to 'execute' declarations and initialize functions
     // (source elements). In case of an illegal redeclaration we need to
     // handle that instead of processing the declarations.