Some cleanup of the toplevel code generator:

* Rename the operation of filling a context with a value.  Formerly it
  was 'Move', now it's 'Apply' so as to avoid confusion with various
  other Moves (eg, in the toplevel codegen, in the macro assemblers).

* Use the abstraction Drop rather than math on the stack pointer.

* Add a predicate on AST expression nodes to abstract a repeated test
  whether we should us a regular (named) IC or a keyed IC.

Review URL: http://codereview.chromium.org/546006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3580 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/codegen-arm.cc

@@ -614,15 +614,7 @@ void CodeGenerator::LoadReference(Reference* ref) {
     // The expression is either a property or a variable proxy that rewrites
     // to a property.
     LoadAndSpill(property->obj());
-    // We use a named reference if the key is a literal symbol, unless it is
-    // a string that can be legally parsed as an integer.  This is because
-    // otherwise we will not get into the slow case code that handles [] on
-    // String objects.
-    Literal* literal = property->key()->AsLiteral();
-    uint32_t dummy;
-    if (literal != NULL &&
-        literal->handle()->IsSymbol() &&
-        !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
+    if (property->key()->IsPropertyName()) {
       ref->set_type(Reference::NAMED);
     } else {
       LoadAndSpill(property->key());

src/arm/macro-assembler-arm.cc

@@ -162,9 +162,9 @@ void MacroAssembler::StackLimitCheck(Label* on_stack_overflow) {
 }
 
 
-void MacroAssembler::Drop(int stack_elements, Condition cond) {
-  if (stack_elements > 0) {
-    add(sp, sp, Operand(stack_elements * kPointerSize), LeaveCC, cond);
+void MacroAssembler::Drop(int count, Condition cond) {
+  if (count > 0) {
+    add(sp, sp, Operand(count * kPointerSize), LeaveCC, cond);
   }
 }
 

src/arm/macro-assembler-arm.h

@@ -64,7 +64,11 @@ class MacroAssembler: public Assembler {
   void Call(byte* target, RelocInfo::Mode rmode, Condition cond = al);
   void Call(Handle<Code> code, RelocInfo::Mode rmode, Condition cond = al);
   void Ret(Condition cond = al);
-  void Drop(int stack_elements, Condition cond = al);
+
+  // Emit code to discard a non-negative number of pointer-sized elements
+  // from the stack, clobbering only the sp register.
+  void Drop(int count, Condition cond = al);
+
   void Call(Label* target);
   void Move(Register dst, Handle<Object> value);
   // Jumps to the label at the index given by the Smi in "index".

src/ast.h

@@ -187,6 +187,11 @@ class Expression: public AstNode {
   virtual bool IsValidJSON() { return false; }
   virtual bool IsValidLeftHandSide() { return false; }
 
+  // Symbols that cannot be parsed as array indices are considered property
+  // names.  We do not treat symbols that can be array indexes as property
+  // names because [] for string objects is handled only by keyed ICs.
+  virtual bool IsPropertyName() { return false; }
+
   // Mark the expression as being compiled as an expression
   // statement. This is used to transform postfix increments to
   // (faster) prefix increments.
@@ -707,6 +712,14 @@ class Literal: public Expression {
 
   virtual bool IsValidJSON() { return true; }
 
+  virtual bool IsPropertyName() {
+    if (handle_->IsSymbol()) {
+      uint32_t ignored;
+      return !String::cast(*handle_)->AsArrayIndex(&ignored);
+    }
+    return false;
+  }
+
   // Identity testers.
   bool IsNull() const { return handle_.is_identical_to(Factory::null_value()); }
   bool IsTrue() const { return handle_.is_identical_to(Factory::true_value()); }

src/compiler.cc

@@ -902,11 +902,7 @@ void CodeGenSelector::VisitAssignment(Assignment* expr) {
     // We will only visit the key during code generation for keyed property
     // stores.  Leave its expression context uninitialized for named
     // property stores.
-    Literal* lit = prop->key()->AsLiteral();
-    uint32_t ignored;
-    if (lit == NULL ||
-        !lit->handle()->IsSymbol() ||
-        String::cast(*(lit->handle()))->AsArrayIndex(&ignored)) {
+    if (!prop->key()->IsPropertyName()) {
       ProcessExpression(prop->key(), Expression::kValue);
       CHECK_BAILOUT;
     }
@@ -1030,11 +1026,7 @@ void CodeGenSelector::VisitCountOperation(CountOperation* expr) {
     // We will only visit the key during code generation for keyed property
     // stores.  Leave its expression context uninitialized for named
     // property stores.
-    Literal* lit = prop->key()->AsLiteral();
-    uint32_t ignored;
-    if (lit == NULL ||
-        !lit->handle()->IsSymbol() ||
-        String::cast(*(lit->handle()))->AsArrayIndex(&ignored)) {
+    if (!prop->key()->IsPropertyName()) {
       ProcessExpression(prop->key(), Expression::kValue);
       CHECK_BAILOUT;
     }

src/fast-codegen.cc

@@ -75,6 +75,39 @@ int FastCodeGenerator::SlotOffset(Slot* slot) {
 }
 
 
+void FastCodeGenerator::Apply(Expression::Context context, Register reg) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      break;
+    case Expression::kValue:
+      __ push(reg);
+      break;
+    case Expression::kTest:
+      TestAndBranch(reg, true_label_, false_label_);
+      break;
+    case Expression::kValueTest: {
+      Label discard;
+      __ push(reg);
+      TestAndBranch(reg, true_label_, &discard);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(false_label_);
+      break;
+    }
+    case Expression::kTestValue: {
+      Label discard;
+      __ push(reg);
+      TestAndBranch(reg, &discard, false_label_);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(true_label_);
+    }
+  }
+}
+
+
 void FastCodeGenerator::VisitDeclarations(
     ZoneList<Declaration*>* declarations) {
   int length = declarations->length();
@@ -624,7 +657,7 @@ void FastCodeGenerator::VisitSlot(Slot* expr) {
 
 void FastCodeGenerator::VisitLiteral(Literal* expr) {
   Comment cmnt(masm_, "[ Literal");
-  Move(expr->context(), expr);
+  Apply(expr->context(), expr);
 }
 
 

src/fast-codegen.h

@@ -212,10 +212,23 @@ class FastCodeGenerator: public AstVisitor {
 
 
   int SlotOffset(Slot* slot);
-  void Move(Expression::Context destination, Register source);
-  void MoveTOS(Expression::Context destination);
-  void Move(Expression::Context destination, Slot* source, Register scratch);
-  void Move(Expression::Context destination, Literal* source);
+
+  // Emit code to complete the evaluation of an expression based on its
+  // expression context and given its value is in a register, non-lookup
+  // slot, or a literal.
+  void Apply(Expression::Context context, Register reg);
+  void Apply(Expression::Context context, Slot* slot, Register scratch);
+  void Apply(Expression::Context context, Literal* lit);
+
+  // Emit code to complete the evaluation of an expression based on its
+  // expression context and given its value is on top of the stack.
+  void ApplyTOS(Expression::Context context);
+
+  // Emit code to discard count elements from the top of stack, then
+  // complete the evaluation of an expression based on its expression
+  // context and given its value is in a register.
+  void DropAndApply(int count, Expression::Context context, Register reg);
+
   void Move(Slot* dst, Register source, Register scratch1, Register scratch2);
   void Move(Register dst, Slot* source);
 
@@ -224,12 +237,6 @@ class FastCodeGenerator: public AstVisitor {
   // register.
   MemOperand EmitSlotSearch(Slot* slot, Register scratch);
 
-  // Drop the TOS, and store source to destination.
-  // If destination is TOS, just overwrite TOS with source.
-  void DropAndMove(Expression::Context destination,
-                   Register source,
-                   int drop_count = 1);
-
   // Test the JavaScript value in source as if in a test context, compile
   // control flow to a pair of labels.
   void TestAndBranch(Register source, Label* true_label, Label* false_label);

src/ia32/codegen-ia32.cc

@@ -664,15 +664,7 @@ void CodeGenerator::LoadReference(Reference* ref) {
     // The expression is either a property or a variable proxy that rewrites
     // to a property.
     Load(property->obj());
-    // We use a named reference if the key is a literal symbol, unless it is
-    // a string that can be legally parsed as an integer.  This is because
-    // otherwise we will not get into the slow case code that handles [] on
-    // String objects.
-    Literal* literal = property->key()->AsLiteral();
-    uint32_t dummy;
-    if (literal != NULL &&
-        literal->handle()->IsSymbol() &&
-        !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
+    if (property->key()->IsPropertyName()) {
       ref->set_type(Reference::NAMED);
     } else {
       Load(property->key());

src/ia32/macro-assembler-ia32.h

@@ -368,6 +368,8 @@ class MacroAssembler: public Assembler {
 
   void Ret();
 
+  // Emit code to discard a non-negative number of pointer-sized elements
+  // from the stack, clobbering only the esp register.
   void Drop(int element_count);
 
   void Call(Label* target) { call(target); }

src/x64/codegen-x64.cc

@@ -4256,15 +4256,7 @@ void CodeGenerator::LoadReference(Reference* ref) {
     // The expression is either a property or a variable proxy that rewrites
     // to a property.
     Load(property->obj());
-    // We use a named reference if the key is a literal symbol, unless it is
-    // a string that can be legally parsed as an integer.  This is because
-    // otherwise we will not get into the slow case code that handles [] on
-    // String objects.
-    Literal* literal = property->key()->AsLiteral();
-    uint32_t dummy;
-    if (literal != NULL &&
-        literal->handle()->IsSymbol() &&
-        !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
+    if (property->key()->IsPropertyName()) {
       ref->set_type(Reference::NAMED);
     } else {
       Load(property->key());

src/x64/macro-assembler-x64.h

@@ -415,7 +415,11 @@ class MacroAssembler: public Assembler {
   void Cmp(Register dst, Handle<Object> source);
   void Cmp(const Operand& dst, Handle<Object> source);
   void Push(Handle<Object> source);
+
+  // Emit code to discard a non-negative number of pointer-sized elements
+  // from the stack, clobbering only the rsp register.
   void Drop(int stack_elements);
+
   void Call(Label* target) { call(target); }
 
   // Control Flow