Experimental: allow the register allocator to work for for...in...

src/codegen-ia32.cc

Index: src/codegen-ia32.cc
===================================================================
--- src/codegen-ia32.cc	(revision 1291)
+++ src/codegen-ia32.cc	(working copy)
@@ -1488,6 +1488,7 @@
 
 void CodeGenerator::VisitStatements(ZoneList<Statement*>* statements) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   for (int i = 0; has_valid_frame() && i < statements->length(); i++) {
     Visit(statements->at(i));
   }
@@ -1496,6 +1497,7 @@
 
 void CodeGenerator::VisitBlock(Block* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Block");
   CodeForStatementPosition(node);
   node->set_break_stack_height(break_stack_height_);
@@ -1508,6 +1510,7 @@
 
 
 void CodeGenerator::DeclareGlobals(Handle<FixedArray> pairs) {
+  ASSERT(HasValidEntryRegisters());
   frame_->Push(pairs);
 
   // Duplicate the context register.
@@ -1521,6 +1524,7 @@
 
 
 void CodeGenerator::VisitDeclaration(Declaration* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Declaration");
   CodeForStatementPosition(node);
   Variable* var = node->proxy()->var();
@@ -1585,6 +1589,7 @@
 
 void CodeGenerator::VisitExpressionStatement(ExpressionStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ ExpressionStatement");
   CodeForStatementPosition(node);
   Expression* expression = node->expression();
@@ -1597,6 +1602,7 @@
 
 void CodeGenerator::VisitEmptyStatement(EmptyStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "// EmptyStatement");
   CodeForStatementPosition(node);
   // nothing to do
@@ -1605,6 +1611,7 @@
 
 void CodeGenerator::VisitIfStatement(IfStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ IfStatement");
   // Generate different code depending on which parts of the if statement
   // are present or not.
@@ -1708,6 +1715,7 @@
 
 void CodeGenerator::VisitContinueStatement(ContinueStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ ContinueStatement");
   CodeForStatementPosition(node);
   CleanStack(break_stack_height_ - node->target()->break_stack_height());
@@ -1717,6 +1725,7 @@
 
 void CodeGenerator::VisitBreakStatement(BreakStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ BreakStatement");
   CodeForStatementPosition(node);
   CleanStack(break_stack_height_ - node->target()->break_stack_height());
@@ -1726,6 +1735,7 @@
 
 void CodeGenerator::VisitReturnStatement(ReturnStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ ReturnStatement");
 
   if (function_return_is_shadowed_) {
@@ -1794,6 +1804,7 @@
 
 void CodeGenerator::VisitWithEnterStatement(WithEnterStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ WithEnterStatement");
   CodeForStatementPosition(node);
   Load(node->expression());
@@ -1823,6 +1834,7 @@
 
 void CodeGenerator::VisitWithExitStatement(WithExitStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ WithExitStatement");
   CodeForStatementPosition(node);
   // Pop context.
@@ -1959,6 +1971,7 @@
 
 void CodeGenerator::VisitSwitchStatement(SwitchStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ SwitchStatement");
   CodeForStatementPosition(node);
   node->set_break_stack_height(break_stack_height_);
@@ -2100,6 +2113,7 @@
 
 void CodeGenerator::VisitLoopStatement(LoopStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ LoopStatement");
   CodeForStatementPosition(node);
   node->set_break_stack_height(break_stack_height_);
@@ -2314,7 +2328,7 @@
 
 void CodeGenerator::VisitForInStatement(ForInStatement* node) {
   ASSERT(!in_spilled_code());
-  VirtualFrame::SpilledScope spilled_scope(this);
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ ForInStatement");
   CodeForStatementPosition(node);
 
@@ -2327,172 +2341,233 @@
   node->break_target()->Initialize(this);
   node->continue_target()->Initialize(this);
 
+  // Stack layout in body (from the top of the frame downward).
+  // [iteration counter (smi)] <- element 0
+  // [length of array (smi)]   <- element 1
+  // [FixedArray]              <- element 2
+  // [Map or 0]                <- element 3
+  // [Object being iterated]   <- element 4
+
   JumpTarget primitive(this);
   JumpTarget jsobject(this);
   JumpTarget fixed_array(this);
-  JumpTarget entry(this, JumpTarget::BIDIRECTIONAL);
+  JumpTarget condition(this, JumpTarget::BIDIRECTIONAL);
   JumpTarget end_del_check(this);
   JumpTarget exit(this);
 
-  // Get the object to enumerate over (converted to JSObject).
-  LoadAndSpill(node->enumerable());
+  // Get the object to iterate over.
+  Load(node->enumerable());
 
   // Both SpiderMonkey and kjs ignore null and undefined in contrast
   // to the specification.  12.6.4 mandates a call to ToObject.
-  frame_->EmitPop(eax);
-
-  // eax: value to be iterated over
-  __ cmp(eax, Factory::undefined_value());
+  Result object = frame_->Pop();
+  object.ToRegister();
+  __ cmp(object.reg(), Factory::undefined_value());
   exit.Branch(equal);
-  __ cmp(eax, Factory::null_value());
+  __ cmp(object.reg(), Factory::null_value());
   exit.Branch(equal);
 
-  // Stack layout in body:
-  // [iteration counter (smi)] <- slot 0
-  // [length of array]         <- slot 1
-  // [FixedArray]              <- slot 2
-  // [Map or 0]                <- slot 3
-  // [Object]                  <- slot 4
-
   // Check if enumerable is already a JSObject
-  // eax: value to be iterated over
-  __ test(eax, Immediate(kSmiTagMask));
-  primitive.Branch(zero);
-  __ mov(ecx, FieldOperand(eax, HeapObject::kMapOffset));
-  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
-  __ cmp(ecx, FIRST_JS_OBJECT_TYPE);
-  jsobject.Branch(above_equal);
+  __ test(object.reg(), Immediate(kSmiTagMask));
+  primitive.Branch(zero, &object);
 
-  primitive.Bind();
-  frame_->EmitPush(eax);
-  frame_->InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION, 1);
-  // function call returns the value in eax, which is where we want it below
+  // Use a temporary register to check the instance type.
+  Result temp = allocator_->Allocate();
+  ASSERT(temp.is_valid());
+  __ mov(temp.reg(), FieldOperand(object.reg(), HeapObject::kMapOffset));
+  __ movzx_b(temp.reg(), FieldOperand(temp.reg(), Map::kInstanceTypeOffset));
+  __ cmp(temp.reg(), FIRST_JS_OBJECT_TYPE);
+  temp.Unuse();
+  jsobject.Branch(above_equal, &object);
 
-  jsobject.Bind();
+  primitive.Bind(&object);
+  // Live results:
+  // object: the object being iterated over
+  frame_->Push(&object);
+  object = frame_->InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION, 1);
+
+  jsobject.Bind(&object);
+  // Live results:
+  // object: the object being iterated over
   // Get the set of properties (as a FixedArray or Map).
-  // eax: value to be iterated over
-  frame_->EmitPush(eax);  // push the object being iterated over (slot 4)
+  frame_->Push(&object);  // Push the object being iterated over (slot 4).
 
-  frame_->EmitPush(eax);  // push the Object (slot 4) for the runtime call
-  frame_->CallRuntime(Runtime::kGetPropertyNamesFast, 1);
+  frame_->Dup();  // Duplicate it for the runtime call.
+  Result properties = frame_->CallRuntime(Runtime::kGetPropertyNamesFast, 1);
 
-  // If we got a Map, we can do a fast modification check.
-  // Otherwise, we got a FixedArray, and we have to do a slow check.
-  // eax: map or fixed array (result from call to
-  // Runtime::kGetPropertyNamesFast)
-  __ mov(edx, Operand(eax));
-  __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
-  __ cmp(ecx, Factory::meta_map());
-  fixed_array.Branch(not_equal);
+  // If we got a Map, we can do a fast modification check.  Otherwise,
+  // we got a FixedArray, and we have to do a slow check.  Use a fresh
+  // temporary register to check the map.
+  temp = allocator_->Allocate();
+  ASSERT(temp.is_valid());
+  __ mov(temp.reg(), FieldOperand(properties.reg(), HeapObject::kMapOffset));
+  __ cmp(temp.reg(), Factory::meta_map());
+  // Do not unuse the temp register, we will need one after the branch.
+  fixed_array.Branch(not_equal, &properties);
 
-  // Get enum cache
-  // eax: map (result from call to Runtime::kGetPropertyNamesFast)
-  __ mov(ecx, Operand(eax));
-  __ mov(ecx, FieldOperand(ecx, Map::kInstanceDescriptorsOffset));
+  // Get enum cache.  Properties is a map (from the call to
+  // Runtime::kGetPropertyNamesFast) and temp is a live register
+  // reference (distinct from properties).
+  __ mov(temp.reg(),
+         FieldOperand(properties.reg(), Map::kInstanceDescriptorsOffset));
   // Get the bridge array held in the enumeration index field.
-  __ mov(ecx, FieldOperand(ecx, DescriptorArray::kEnumerationIndexOffset));
+  __ mov(temp.reg(),
+         FieldOperand(temp.reg(), DescriptorArray::kEnumerationIndexOffset));
   // Get the cache from the bridge array.
-  __ mov(edx, FieldOperand(ecx, DescriptorArray::kEnumCacheBridgeCacheOffset));
+  __ mov(temp.reg(),
+         FieldOperand(temp.reg(),
+                      DescriptorArray::kEnumCacheBridgeCacheOffset));
 
-  frame_->EmitPush(eax);  // <- slot 3
-  frame_->EmitPush(edx);  // <- slot 2
-  __ mov(eax, FieldOperand(edx, FixedArray::kLengthOffset));
-  __ shl(eax, kSmiTagSize);
-  frame_->EmitPush(eax);  // <- slot 1
-  frame_->EmitPush(Immediate(Smi::FromInt(0)));  // <- slot 0
-  entry.Jump();
+  frame_->Push(&properties);  // <- slot 3
+  // Duplicate the enum cache so we can fetch the length from it.
+  Result cache = temp;
+  frame_->Push(&temp);  // <- slot 2
 
-  fixed_array.Bind();
-  // eax: fixed array (result from call to Runtime::kGetPropertyNamesFast)
-  frame_->EmitPush(Immediate(Smi::FromInt(0)));  // <- slot 3
-  frame_->EmitPush(eax);  // <- slot 2
+  // Use a fresh temp register to fetch the length.
+  temp = allocator_->Allocate();
+  ASSERT(temp.is_valid());
+  __ mov(temp.reg(), FieldOperand(cache.reg(), FixedArray::kLengthOffset));
+  cache.Unuse();
+  __ shl(temp.reg(), kSmiTagSize);
+  frame_->Push(&temp);  // <- slot 1
+  frame_->Push(Smi::FromInt(0));  // <- slot 0
+  condition.Jump();
 
-  // Push the length of the array and the initial index onto the stack.
-  __ mov(eax, FieldOperand(eax, FixedArray::kLengthOffset));
-  __ shl(eax, kSmiTagSize);
-  frame_->EmitPush(eax);  // <- slot 1
-  frame_->EmitPush(Immediate(Smi::FromInt(0)));  // <- slot 0
+  fixed_array.Bind(&properties);
+  // Live results:
+  // properties: the set of properties as a fixed array (from the call
+  // to Runtime::kGetPropertyNamesFast).
+  frame_->Push(Smi::FromInt(0));  // <- slot 3
+  // Use a fresh temporary register to fetch the length from the
+  // properties array.
+  temp = allocator_->Allocate();
+  ASSERT(temp.is_valid());
+  properties.ToRegister();
+  __ mov(temp.reg(),
+         FieldOperand(properties.reg(), FixedArray::kLengthOffset));
+  __ shl(temp.reg(), kSmiTagSize);
 
-  // Condition.
-  entry.Bind();
-  __ mov(eax, frame_->ElementAt(0));  // load the current count
-  __ cmp(eax, frame_->ElementAt(1));  // compare to the array length
+  frame_->Push(&properties);  // <- slot 2
+  frame_->Push(&temp);  // <- slot 1
+  frame_->Push(Smi::FromInt(0));  // <- slot 0
+
+  condition.Bind();
+  // Live results: none.
+  // Compare the current count (frame element 0) to the array length
+  // (frame element 1).
+  frame_->Dup();
+  Result count = frame_->Pop();
+
+  frame_->PushElementAt(1);
+  Result length = frame_->Pop();
+
+  count.ToRegister();
+  if (length.is_register()) {
+    // Count and length can be the same register, which is OK here.
+    __ cmp(count.reg(), Operand(length.reg()));
+  } else {
+    ASSERT(length.is_constant());
+    __ cmp(count.reg(), length.handle());
+  }
+  length.Unuse();
   node->break_target()->Branch(above_equal);
 
   // Get the i'th entry of the array.
-  __ mov(edx, frame_->ElementAt(2));
-  __ mov(ebx, Operand(edx, eax, times_2,
-                      FixedArray::kHeaderSize - kHeapObjectTag));
+  frame_->PushElementAt(2);
+  Result entry = frame_->Pop();
+  entry.ToRegister();
+  frame_->Spill(entry.reg());
+  // Entry and count can be the same register.  That's OK here because
+  // they will both be absent from the frame after spilling entry and
+  // count is not needed after being read (before entry is written).
+  __ mov(entry.reg(), Operand(entry.reg(),
+                              count.reg(),
+                              times_2,
+                              FixedArray::kHeaderSize - kHeapObjectTag));
+  count.Unuse();
 
-  // Get the expected map from the stack or a zero map in the
-  // permanent slow case eax: current iteration count ebx: i'th entry
-  // of the enum cache
-  __ mov(edx, frame_->ElementAt(3));
   // Check if the expected map still matches that of the enumerable.
   // If not, we have to filter the key.
-  // eax: current iteration count
-  // ebx: i'th entry of the enum cache
-  // edx: expected map value
-  __ mov(ecx, frame_->ElementAt(4));
-  __ mov(ecx, FieldOperand(ecx, HeapObject::kMapOffset));
-  __ cmp(ecx, Operand(edx));
-  end_del_check.Branch(equal);
 
+  // Begin with the enumerable and fetch its map.
+  frame_->PushElementAt(4);
+  temp = frame_->Pop();
+  temp.ToRegister();
+  // We will write to temp.  If it is the same register as entry we
+  // will allocate a fresh register.  Otherwise we can just spill it
+  // from the frame.
+  if (temp.reg().is(entry.reg())) {

[William Hesse, 2009/02/18 10:33:28]

This cannot happen because entry.reg() is spilled above before creating temp. 
Assert that it can't happen.

+    Result fresh = allocator_->Allocate();
+    ASSERT(fresh.is_valid());
+    __ mov(fresh.reg(), temp.reg());
+    temp = fresh;
+  } else {
+    frame_->Spill(temp.reg());
+  }
+  __ mov(temp.reg(), FieldOperand(temp.reg(), HeapObject::kMapOffset));
+
+  // Get the expected map from the stack or a zero map in the
+  // permanent slow case.
+  frame_->PushElementAt(3);
+  Result expected_map = frame_->Pop();
+  if (expected_map.is_register()) {
+    __ cmp(temp.reg(), Operand(expected_map.reg()));
+  } else {
+    ASSERT(expected_map.is_constant());
+    __ cmp(temp.reg(), expected_map.handle());
+  }
+  expected_map.Unuse();
+  temp.Unuse();
+  end_del_check.Branch(equal, &entry);
+
   // Convert the entry to a string (or null if it isn't a property anymore).
-  frame_->EmitPush(frame_->ElementAt(4));  // push enumerable
-  frame_->EmitPush(ebx);  // push entry
-  frame_->InvokeBuiltin(Builtins::FILTER_KEY, CALL_FUNCTION, 2);
-  __ mov(ebx, Operand(eax));
+  frame_->PushElementAt(4);  // Duplicate the enumerable.
+  frame_->Push(&entry);  // Push the entry.
+  entry = frame_->InvokeBuiltin(Builtins::FILTER_KEY, CALL_FUNCTION, 2);
 
   // If the property has been removed while iterating, we just skip it.
-  __ cmp(ebx, Factory::null_value());
+  __ cmp(entry.reg(), Factory::null_value());
   node->continue_target()->Branch(equal);
 
-  end_del_check.Bind();
-  // Store the entry in the 'each' expression and take another spin in the
-  // loop.  edx: i'th entry of the enum cache (or string there of)
-  frame_->EmitPush(ebx);
+  end_del_check.Bind(&entry);
+  // Live results:
+  // entry: the i'th entry of the enum cache.
+  // Store the entry in the 'each' expression and take another spin in
+  // the loop.
+  //
+  // Push the entry before loading the reference, because loading a
+  // reference can visit code (requiring all non-reserved registers to
+  // be held by the frame).
+  frame_->Push(&entry);
+  bool entry_was_duplicated = false;
   { Reference each(this, node->each());
-    // Loading a reference may leave the frame in an unspilled state.
-    frame_->SpillAll();
     if (!each.is_illegal()) {
-      if (each.size() > 0) {
-        frame_->EmitPush(frame_->ElementAt(each.size()));
-      }
-      // If the reference was to a slot we rely on the convenient property
-      // that it doesn't matter whether a value (eg, ebx pushed above) is
-      // right on top of or right underneath a zero-sized reference.
+      // Duplicate the entry and store to the reference.
+      frame_->PushElementAt(each.size());
+      entry_was_duplicated = true;
       each.SetValue(NOT_CONST_INIT);
-      if (each.size() > 0) {
-        // It's safe to pop the value lying on top of the reference before
-        // unloading the reference itself (which preserves the top of stack,
-        // ie, now the topmost value of the non-zero sized reference), since
-        // we will discard the top of stack after unloading the reference
-        // anyway.
-        frame_->Drop();
-      }
     }
   }
-  // Unloading a reference may leave the frame in an unspilled state.
-  frame_->SpillAll();
+  // Discard the i'th entry (and its duplicate if it was duplicated).
+  frame_->Drop(entry_was_duplicated ? 2 : 1);
 
-  // Discard the i'th entry pushed above or else the remainder of the
-  // reference, whichever is currently on top of the stack.
-  frame_->Drop();
-
   // Body.
   CheckStack();  // TODO(1222600): ignore if body contains calls.
-  VisitAndSpill(node->body());
+  Visit(node->body());
 
   // Next.
   node->continue_target()->Bind();
-  frame_->EmitPop(eax);
-  __ add(Operand(eax), Immediate(Smi::FromInt(1)));
-  frame_->EmitPush(eax);
-  entry.Jump();
+  // Live results: none.
+  count = frame_->Pop();
+  count.ToRegister();
+  frame_->Spill(count.reg());
+  __ add(Operand(count.reg()), Immediate(Smi::FromInt(1)));
+  frame_->Push(&count);
+  condition.Jump();
 
   // Cleanup.
   node->break_target()->Bind();
+  // Live results: none.
   frame_->Drop(5);
 
   // Exit.
@@ -2504,6 +2579,7 @@
 
 void CodeGenerator::VisitTryCatch(TryCatch* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   VirtualFrame::SpilledScope spilled_scope(this);
   Comment cmnt(masm_, "[ TryCatch");
   CodeForStatementPosition(node);
@@ -2633,6 +2709,7 @@
 
 void CodeGenerator::VisitTryFinally(TryFinally* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   VirtualFrame::SpilledScope spilled_scope(this);
   Comment cmnt(masm_, "[ TryFinally");
   CodeForStatementPosition(node);
@@ -2802,6 +2879,7 @@
 
 void CodeGenerator::VisitDebuggerStatement(DebuggerStatement* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ DebuggerStatement");
   CodeForStatementPosition(node);
   // Spill everything, even constants, to the frame.
@@ -2825,6 +2903,7 @@
 
 
 void CodeGenerator::VisitFunctionLiteral(FunctionLiteral* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ FunctionLiteral");
 
   // Build the function boilerplate and instantiate it.
@@ -2837,12 +2916,14 @@
 
 void CodeGenerator::VisitFunctionBoilerplateLiteral(
     FunctionBoilerplateLiteral* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ FunctionBoilerplateLiteral");
   InstantiateBoilerplate(node->boilerplate());
 }
 
 
 void CodeGenerator::VisitConditional(Conditional* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Conditional");
   JumpTarget then(this);
   JumpTarget else_(this);
@@ -3024,12 +3105,14 @@
 
 
 void CodeGenerator::VisitSlot(Slot* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Slot");
   LoadFromSlot(node, typeof_state());
 }
 
 
 void CodeGenerator::VisitVariableProxy(VariableProxy* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ VariableProxy");
   Variable* var = node->var();
   Expression* expr = var->rewrite();
@@ -3044,6 +3127,7 @@
 
 
 void CodeGenerator::VisitLiteral(Literal* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Literal");
   if (node->handle()->IsSmi() && !IsInlineSmi(node)) {
     // To prevent long attacker-controlled byte sequences in code, larger
@@ -3096,6 +3180,7 @@
 
 
 void CodeGenerator::VisitRegExpLiteral(RegExpLiteral* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ RegExp Literal");
   DeferredRegExpLiteral* deferred = new DeferredRegExpLiteral(this, node);
 
@@ -3171,6 +3256,7 @@
 
 
 void CodeGenerator::VisitObjectLiteral(ObjectLiteral* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ ObjectLiteral");
   DeferredObjectLiteral* deferred = new DeferredObjectLiteral(this, node);
 
@@ -3272,6 +3358,7 @@
 
 
 void CodeGenerator::VisitArrayLiteral(ArrayLiteral* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ ArrayLiteral");
 
   // Call the runtime to create the array literal.
@@ -3330,6 +3417,7 @@
 
 void CodeGenerator::VisitCatchExtensionObject(CatchExtensionObject* node) {
   ASSERT(!in_spilled_code());
+  ASSERT(HasValidEntryRegisters());
   // Call runtime routine to allocate the catch extension object and
   // assign the exception value to the catch variable.
   Comment cmnt(masm_, "[ CatchExtensionObject");
@@ -3349,6 +3437,7 @@
 
 
 void CodeGenerator::VisitAssignment(Assignment* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Assignment");
   CodeForStatementPosition(node);
 
@@ -3407,6 +3496,7 @@
 
 
 void CodeGenerator::VisitThrow(Throw* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Throw");
   CodeForStatementPosition(node);
 
@@ -3417,6 +3507,7 @@
 
 
 void CodeGenerator::VisitProperty(Property* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Property");
   Reference property(this, node);
   property.GetValue(typeof_state());
@@ -3424,6 +3515,7 @@
 
 
 void CodeGenerator::VisitCall(Call* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ Call");
 
   ZoneList<Expression*>* args = node->arguments();
@@ -3563,6 +3655,7 @@
 
 
 void CodeGenerator::VisitCallNew(CallNew* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ CallNew");
   CodeForStatementPosition(node);
 
@@ -3615,6 +3708,7 @@
 
 
 void CodeGenerator::VisitCallEval(CallEval* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ CallEval");
 
   // In a call to eval, we first call %ResolvePossiblyDirectEval to resolve
@@ -4002,6 +4096,7 @@
 
 
 void CodeGenerator::VisitCallRuntime(CallRuntime* node) {
+  ASSERT(HasValidEntryRegisters());
   if (CheckForInlineRuntimeCall(node)) {
     return;
   }
@@ -4047,6 +4142,7 @@
 
 
 void CodeGenerator::VisitUnaryOperation(UnaryOperation* node) {
+  ASSERT(HasValidEntryRegisters());
   // Note that because of NOT and an optimization in comparison of a typeof
   // expression to a literal string, this function can fail to leave a value
   // on top of the frame or in the cc register.
@@ -4279,6 +4375,7 @@
 
 
 void CodeGenerator::VisitCountOperation(CountOperation* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ CountOperation");
 
   bool is_postfix = node->is_postfix();
@@ -4375,6 +4472,7 @@
 
 
 void CodeGenerator::VisitBinaryOperation(BinaryOperation* node) {
+  ASSERT(HasValidEntryRegisters());
   // Note that due to an optimization in comparison operations (typeof
   // compared to a string literal), we can evaluate a binary expression such
   // as AND or OR and not leave a value on the frame or in the cc register.
@@ -4517,6 +4615,7 @@
 
 
 void CodeGenerator::VisitThisFunction(ThisFunction* node) {
+  ASSERT(HasValidEntryRegisters());
   frame_->PushFunction();
 }
 
@@ -4534,6 +4633,7 @@
 
 
 void CodeGenerator::VisitCompareOperation(CompareOperation* node) {
+  ASSERT(HasValidEntryRegisters());
   Comment cmnt(masm_, "[ CompareOperation");
 
   // Get the expressions from the node.