Remove stack height tracking from ia32 non-optimizing code generator.

Review URL: http://codereview.chromium.org/8340023

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9857 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 0dd71e8..9f11616 100644 (file)
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -430,7 +430,6 @@ DEFINE_bool(print_json_ast, false, "print source AST as JSON")
 DEFINE_bool(print_builtin_json_ast, false,
             "print source AST for builtins as JSON")
 DEFINE_string(stop_at, "", "function name where to insert a breakpoint")
-DEFINE_bool(verify_stack_height, false, "verify stack height tracing on ia32")
 
 // compiler.cc
 DEFINE_bool(print_builtin_scopes, false, "print scopes for builtins")

diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index 27c509f..6c798ac 100644 (file)
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -410,7 +410,6 @@ void FullCodeGenerator::AccumulatorValueContext::Plug(Register reg) const {
 
 void FullCodeGenerator::StackValueContext::Plug(Register reg) const {
   __ push(reg);
-  codegen()->increment_stack_height();
 }
 
 
@@ -424,13 +423,11 @@ void FullCodeGenerator::TestContext::Plug(Register reg) const {
 
 void FullCodeGenerator::EffectContext::PlugTOS() const {
   __ Drop(1);
-  codegen()->decrement_stack_height();
 }
 
 
 void FullCodeGenerator::AccumulatorValueContext::PlugTOS() const {
   __ pop(result_register());
-  codegen()->decrement_stack_height();
 }
 
 
@@ -441,7 +438,6 @@ void FullCodeGenerator::StackValueContext::PlugTOS() const {
 void FullCodeGenerator::TestContext::PlugTOS() const {
   // For simplicity we always test the accumulator register.
   __ pop(result_register());
-  codegen()->decrement_stack_height();
   codegen()->PrepareForBailoutBeforeSplit(TOS_REG, false, NULL, NULL);
   codegen()->DoTest(this);
 }
@@ -979,7 +975,6 @@ void FullCodeGenerator::VisitWithStatement(WithStatement* stmt) {
   VisitForStackValue(stmt->expression());
   PushFunctionArgumentForContextAllocation();
   __ CallRuntime(Runtime::kPushWithContext, 2);
-  decrement_stack_height();
   StoreToFrameField(StandardFrameConstants::kContextOffset, context_register());
 
   { WithOrCatch body(this);
@@ -1149,13 +1144,10 @@ void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   // Try block code. Sets up the exception handler chain.
   __ bind(&try_handler_setup);
   {
-    const int delta = StackHandlerConstants::kSize / kPointerSize;
     TryCatch try_block(this);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_CATCH_HANDLER);
-    increment_stack_height(delta);
     Visit(stmt->try_block());
     __ PopTryHandler();
-    decrement_stack_height(delta);
   }
   __ bind(&done);
 }
@@ -1187,7 +1179,6 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   // cooked before GC.
   Label finally_entry;
   Label try_handler_setup;
-  const int original_stack_height = stack_height();
 
   // Setup the try-handler chain. Use a call to
   // Jump to try-handler setup and try-block code. Use call to put try-handler
@@ -1209,7 +1200,6 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
     // Finally block implementation.
     Finally finally_block(this);
     EnterFinallyBlock();
-    set_stack_height(original_stack_height + Finally::kElementCount);
     Visit(stmt->finally_block());
     ExitFinallyBlock();  // Return to the calling code.
   }
@@ -1217,13 +1207,10 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   __ bind(&try_handler_setup);
   {
     // Setup try handler (stack pointer registers).
-    const int delta = StackHandlerConstants::kSize / kPointerSize;
     TryFinally try_block(this, &finally_entry);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_FINALLY_HANDLER);
-    set_stack_height(original_stack_height + delta);
     Visit(stmt->try_block());
     __ PopTryHandler();
-    set_stack_height(original_stack_height);
   }
   // Execute the finally block on the way out.  Clobber the unpredictable
   // value in the accumulator with one that's safe for GC.  The finally
@@ -1253,7 +1240,6 @@ void FullCodeGenerator::VisitConditional(Conditional* expr) {
   __ bind(&true_case);
   SetExpressionPosition(expr->then_expression(),
                         expr->then_expression_position());
-  int start_stack_height = stack_height();
   if (context()->IsTest()) {
     const TestContext* for_test = TestContext::cast(context());
     VisitForControl(expr->then_expression(),
@@ -1267,7 +1253,6 @@ void FullCodeGenerator::VisitConditional(Conditional* expr) {
 
   PrepareForBailoutForId(expr->ElseId(), NO_REGISTERS);
   __ bind(&false_case);
-  set_stack_height(start_stack_height);
   if (context()->IsTest()) ForwardBailoutToChild(expr);
   SetExpressionPosition(expr->else_expression(),
                         expr->else_expression_position());
@@ -1308,11 +1293,8 @@ void FullCodeGenerator::VisitSharedFunctionInfoLiteral(
 
 void FullCodeGenerator::VisitThrow(Throw* expr) {
   Comment cmnt(masm_, "[ Throw");
-  // Throw has no effect on the stack height or the current expression context.
-  // Usually the expression context is null, because throw is a statement.
   VisitForStackValue(expr->exception());
   __ CallRuntime(Runtime::kThrow, 1);
-  decrement_stack_height();
   // Never returns here.
 }
 

diff --git a/src/full-codegen.h b/src/full-codegen.h
index 5203c2a..e5693ed 100644 (file)
--- a/src/full-codegen.h
+++ b/src/full-codegen.h
@@ -83,7 +83,6 @@ class FullCodeGenerator: public AstVisitor {
         scope_(NULL),
         nesting_stack_(NULL),
         loop_depth_(0),
-        stack_height_(0),
         context_(NULL),
         bailout_entries_(0),
         stack_checks_(2),  // There's always at least one.
@@ -534,35 +533,6 @@ class FullCodeGenerator: public AstVisitor {
     loop_depth_--;
   }
 
-#if defined(V8_TARGET_ARCH_IA32)
-  int stack_height() { return stack_height_; }
-  void set_stack_height(int depth) { stack_height_ = depth; }
-  void increment_stack_height() { stack_height_++; }
-  void increment_stack_height(int delta) { stack_height_ += delta; }
-  void decrement_stack_height() {
-    if (FLAG_verify_stack_height) {
-      ASSERT(stack_height_ > 0);
-    }
-    stack_height_--;
-  }
-  void decrement_stack_height(int delta) {
-    stack_height_-= delta;
-    if (FLAG_verify_stack_height) {
-      ASSERT(stack_height_ >= 0);
-    }
-  }
-  // Call this function only if FLAG_verify_stack_height is true.
-  void verify_stack_height();  // Generates a runtime check of esp - ebp.
-#else
-  int stack_height() { return 0; }
-  void set_stack_height(int depth) {}
-  void increment_stack_height() {}
-  void increment_stack_height(int delta) {}
-  void decrement_stack_height() {}
-  void decrement_stack_height(int delta) {}
-  void verify_stack_height() {}
-#endif  // V8_TARGET_ARCH_IA32
-
   MacroAssembler* masm() { return masm_; }
 
   class ExpressionContext;
@@ -625,10 +595,6 @@ class FullCodeGenerator: public AstVisitor {
 
     virtual ~ExpressionContext() {
       codegen_->set_new_context(old_);
-      if (FLAG_verify_stack_height) {
-        ASSERT_EQ(expected_stack_height_, codegen()->stack_height());
-        codegen()->verify_stack_height();
-      }
     }
 
     Isolate* isolate() const { return codegen_->isolate(); }
@@ -682,7 +648,6 @@ class FullCodeGenerator: public AstVisitor {
     FullCodeGenerator* codegen() const { return codegen_; }
     MacroAssembler* masm() const { return masm_; }
     MacroAssembler* masm_;
-    int expected_stack_height_;  // The expected stack height esp - ebp on exit.
 
    private:
     const ExpressionContext* old_;
@@ -692,9 +657,7 @@ class FullCodeGenerator: public AstVisitor {
   class AccumulatorValueContext : public ExpressionContext {
    public:
     explicit AccumulatorValueContext(FullCodeGenerator* codegen)
-        : ExpressionContext(codegen) {
-      expected_stack_height_ = codegen->stack_height();
-    }
+        : ExpressionContext(codegen) { }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
@@ -715,9 +678,7 @@ class FullCodeGenerator: public AstVisitor {
   class StackValueContext : public ExpressionContext {
    public:
     explicit StackValueContext(FullCodeGenerator* codegen)
-        : ExpressionContext(codegen) {
-      expected_stack_height_ = codegen->stack_height() + 1;
-    }
+        : ExpressionContext(codegen) { }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
@@ -746,9 +707,7 @@ class FullCodeGenerator: public AstVisitor {
           condition_(condition),
           true_label_(true_label),
           false_label_(false_label),
-          fall_through_(fall_through) {
-      expected_stack_height_ = codegen->stack_height();
-    }
+          fall_through_(fall_through) { }
 
     static const TestContext* cast(const ExpressionContext* context) {
       ASSERT(context->IsTest());
@@ -785,10 +744,7 @@ class FullCodeGenerator: public AstVisitor {
   class EffectContext : public ExpressionContext {
    public:
     explicit EffectContext(FullCodeGenerator* codegen)
-        : ExpressionContext(codegen) {
-      expected_stack_height_ = codegen->stack_height();
-    }
-
+        : ExpressionContext(codegen) { }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
@@ -812,7 +768,6 @@ class FullCodeGenerator: public AstVisitor {
   Label return_label_;
   NestedStatement* nesting_stack_;
   int loop_depth_;
-  int stack_height_;
   const ExpressionContext* context_;
   ZoneList<BailoutEntry> bailout_entries_;
   ZoneList<BailoutEntry> stack_checks_;

diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 2a99eba..d2028db 100644 (file)
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -169,11 +169,6 @@ void FullCodeGenerator::Generate(CompilationInfo* info) {
     }
   }
 
-  set_stack_height(2 + scope()->num_stack_slots());
-  if (FLAG_verify_stack_height) {
-    verify_stack_height();
-  }
-
   bool function_in_register = true;
 
   // Possibly allocate a local context.
@@ -372,15 +367,6 @@ void FullCodeGenerator::EmitReturnSequence() {
 }
 
 
-void FullCodeGenerator::verify_stack_height() {
-  ASSERT(FLAG_verify_stack_height);
-  __ sub(ebp, Immediate(kPointerSize * stack_height()));
-  __ cmp(ebp, esp);
-  __ Assert(equal, "Full codegen stack height not as expected.");
-  __ add(ebp, Immediate(kPointerSize * stack_height()));
-}
-
-
 void FullCodeGenerator::EffectContext::Plug(Variable* var) const {
   ASSERT(var->IsStackAllocated() || var->IsContextSlot());
 }
@@ -397,7 +383,6 @@ void FullCodeGenerator::StackValueContext::Plug(Variable* var) const {
   MemOperand operand = codegen()->VarOperand(var, result_register());
   // Memory operands can be pushed directly.
   __ push(operand);
-  codegen()->increment_stack_height();
 }
 
 
@@ -451,7 +436,6 @@ void FullCodeGenerator::StackValueContext::Plug(Handle<Object> lit) const {
   } else {
     __ push(Immediate(lit));
   }
-  codegen()->increment_stack_height();
 }
 
 
@@ -489,7 +473,6 @@ void FullCodeGenerator::EffectContext::DropAndPlug(int count,
                                                    Register reg) const {
   ASSERT(count > 0);
   __ Drop(count);
-  codegen()->decrement_stack_height(count);
 }
 
 
@@ -499,7 +482,6 @@ void FullCodeGenerator::AccumulatorValueContext::DropAndPlug(
   ASSERT(count > 0);
   __ Drop(count);
   __ Move(result_register(), reg);
-  codegen()->decrement_stack_height(count);
 }
 
 
@@ -508,7 +490,6 @@ void FullCodeGenerator::StackValueContext::DropAndPlug(int count,
   ASSERT(count > 0);
   if (count > 1) __ Drop(count - 1);
   __ mov(Operand(esp, 0), reg);
-  codegen()->decrement_stack_height(count - 1);
 }
 
 
@@ -520,7 +501,6 @@ void FullCodeGenerator::TestContext::DropAndPlug(int count,
   __ Move(result_register(), reg);
   codegen()->PrepareForBailoutBeforeSplit(TOS_REG, false, NULL, NULL);
   codegen()->DoTest(this);
-  codegen()->decrement_stack_height(count);
 }
 
 
@@ -554,7 +534,6 @@ void FullCodeGenerator::StackValueContext::Plug(
   __ bind(materialize_false);
   __ push(Immediate(isolate()->factory()->false_value()));
   __ bind(&done);
-  codegen()->increment_stack_height();
 }
 
 
@@ -582,7 +561,6 @@ void FullCodeGenerator::StackValueContext::Plug(bool flag) const {
       ? isolate()->factory()->true_value()
       : isolate()->factory()->false_value();
   __ push(Immediate(value));
-  codegen()->increment_stack_height();
 }
 
 
@@ -784,18 +762,14 @@ void FullCodeGenerator::EmitDeclaration(VariableProxy* proxy,
       // Note: For variables we must not push an initial value (such as
       // 'undefined') because we may have a (legal) redeclaration and we
       // must not destroy the current value.
-      increment_stack_height(3);
       if (function != NULL) {
         VisitForStackValue(function);
       } else if (binding_needs_init) {
         __ push(Immediate(isolate()->factory()->the_hole_value()));
-        increment_stack_height();
       } else {
         __ push(Immediate(Smi::FromInt(0)));  // Indicates no initial value.
-        increment_stack_height();
       }
       __ CallRuntime(Runtime::kDeclareContextSlot, 4);
-      decrement_stack_height(4);
       break;
     }
   }
@@ -820,7 +794,6 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
   Breakable nested_statement(this, stmt);
   SetStatementPosition(stmt);
 
-  int switch_clause_stack_height = stack_height();
   // Keep the switch value on the stack until a case matches.
   VisitForStackValue(stmt->tag());
   PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
@@ -885,7 +858,6 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     __ jmp(default_clause->body_target());
   }
 
-  set_stack_height(switch_clause_stack_height);
   // Compile all the case bodies.
   for (int i = 0; i < clauses->length(); i++) {
     Comment cmnt(masm_, "[ Case body");
@@ -927,7 +899,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
   __ bind(&done_convert);
   __ push(eax);
-  increment_stack_height();
 
   // Check for proxies.
   Label call_runtime;
@@ -1025,8 +996,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(eax);  // Fixed array length (as smi).
   __ push(Immediate(Smi::FromInt(0)));  // Initial index.
 
-  // 1 ~ The object has already been pushed.
-  increment_stack_height(ForIn::kElementCount - 1);
   // Generate code for doing the condition check.
   __ bind(&loop);
   __ mov(eax, Operand(esp, 0 * kPointerSize));  // Get the current index.
@@ -1088,7 +1057,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ bind(loop_statement.break_label());
   __ add(esp, Immediate(5 * kPointerSize));
 
-  decrement_stack_height(ForIn::kElementCount);
   // Exit and decrement the loop depth.
   __ bind(&exit);
   decrement_loop_depth();
@@ -1410,7 +1378,6 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
     if (!result_saved) {
       __ push(eax);  // Save result on the stack
       result_saved = true;
-      increment_stack_height();
     }
     switch (property->kind()) {
       case ObjectLiteral::Property::MATERIALIZED_LITERAL:
@@ -1435,7 +1402,6 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
         // Fall through.
       case ObjectLiteral::Property::PROTOTYPE:
         __ push(Operand(esp, 0));  // Duplicate receiver.
-        increment_stack_height();
         VisitForStackValue(key);
         VisitForStackValue(value);
         if (property->emit_store()) {
@@ -1444,20 +1410,16 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
         } else {
           __ Drop(3);
         }
-        decrement_stack_height(3);
         break;
       case ObjectLiteral::Property::SETTER:
       case ObjectLiteral::Property::GETTER:
         __ push(Operand(esp, 0));  // Duplicate receiver.
-        increment_stack_height();
         VisitForStackValue(key);
         __ push(Immediate(property->kind() == ObjectLiteral::Property::SETTER ?
                           Smi::FromInt(1) :
                           Smi::FromInt(0)));
-        increment_stack_height();
         VisitForStackValue(value);
         __ CallRuntime(Runtime::kDefineAccessor, 4);
-        decrement_stack_height(4);
         break;
       default: UNREACHABLE();
     }
@@ -1532,7 +1494,6 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
     if (!result_saved) {
       __ push(eax);
       result_saved = true;
-      increment_stack_height();
     }
     VisitForAccumulatorValue(subexpr);
 
@@ -1560,9 +1521,7 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
   // Invalid left-hand sides are rewritten to have a 'throw ReferenceError'
   // on the left-hand side.
   if (!expr->target()->IsValidLeftHandSide()) {
-    ASSERT(expr->target()->AsThrow() != NULL);
-    VisitInCurrentContext(expr->target());  // Throw does not plug the context
-    context()->Plug(eax);
+    VisitForEffect(expr->target());
     return;
   }
 
@@ -1587,7 +1546,6 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
         // We need the receiver both on the stack and in the accumulator.
         VisitForAccumulatorValue(property->obj());
         __ push(result_register());
-        increment_stack_height();
       } else {
         VisitForStackValue(property->obj());
       }
@@ -1598,7 +1556,6 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
         VisitForAccumulatorValue(property->key());
         __ mov(edx, Operand(esp, 0));
         __ push(eax);
-        increment_stack_height();
       } else {
         VisitForStackValue(property->obj());
         VisitForStackValue(property->key());
@@ -1630,7 +1587,6 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
 
     Token::Value op = expr->binary_op();
     __ push(eax);  // Left operand goes on the stack.
-    increment_stack_height();
     VisitForAccumulatorValue(expr->value());
 
     OverwriteMode mode = expr->value()->ResultOverwriteAllowed()
@@ -1700,7 +1656,6 @@ void FullCodeGenerator::EmitInlineSmiBinaryOp(BinaryOperation* expr,
   // stack. Right operand is in eax.
   Label smi_case, done, stub_call;
   __ pop(edx);
-  decrement_stack_height();
   __ mov(ecx, eax);
   __ or_(eax, edx);
   JumpPatchSite patch_site(masm_);
@@ -1792,7 +1747,6 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr,
                                      Token::Value op,
                                      OverwriteMode mode) {
   __ pop(edx);
-  decrement_stack_height();
   BinaryOpStub stub(op, mode);
   JumpPatchSite patch_site(masm_);    // unbound, signals no inlined smi code.
   __ call(stub.GetCode(), RelocInfo::CODE_TARGET, expr->id());
@@ -1805,9 +1759,7 @@ void FullCodeGenerator::EmitAssignment(Expression* expr, int bailout_ast_id) {
   // Invalid left-hand sides are rewritten to have a 'throw
   // ReferenceError' on the left-hand side.
   if (!expr->IsValidLeftHandSide()) {
-    ASSERT(expr->AsThrow() != NULL);
-    VisitInCurrentContext(expr);  // Throw does not plug the context
-    context()->Plug(eax);
+    VisitForEffect(expr);
     return;
   }
 
@@ -1831,11 +1783,9 @@ void FullCodeGenerator::EmitAssignment(Expression* expr, int bailout_ast_id) {
     }
     case NAMED_PROPERTY: {
       __ push(eax);  // Preserve value.
-      increment_stack_height();
       VisitForAccumulatorValue(prop->obj());
       __ mov(edx, eax);
       __ pop(eax);  // Restore value.
-      decrement_stack_height();
       __ mov(ecx, prop->key()->AsLiteral()->handle());
       Handle<Code> ic = is_strict_mode()
           ? isolate()->builtins()->StoreIC_Initialize_Strict()
@@ -1845,14 +1795,11 @@ void FullCodeGenerator::EmitAssignment(Expression* expr, int bailout_ast_id) {
     }
     case KEYED_PROPERTY: {
       __ push(eax);  // Preserve value.
-      increment_stack_height();
       VisitForStackValue(prop->obj());
       VisitForAccumulatorValue(prop->key());
       __ mov(ecx, eax);
       __ pop(edx);
-      decrement_stack_height();
       __ pop(eax);  // Restore value.
-      decrement_stack_height();
       Handle<Code> ic = is_strict_mode()
           ? isolate()->builtins()->KeyedStoreIC_Initialize_Strict()
           : isolate()->builtins()->KeyedStoreIC_Initialize();
@@ -1979,7 +1926,6 @@ void FullCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
     __ mov(edx, Operand(esp, 0));
   } else {
     __ pop(edx);
-    decrement_stack_height();
   }
   Handle<Code> ic = is_strict_mode()
       ? isolate()->builtins()->StoreIC_Initialize_Strict()
@@ -1993,7 +1939,6 @@ void FullCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
     __ CallRuntime(Runtime::kToFastProperties, 1);
     __ pop(eax);
     __ Drop(1);
-    decrement_stack_height();
   }
   PrepareForBailoutForId(expr->AssignmentId(), TOS_REG);
   context()->Plug(eax);
@@ -2015,12 +1960,10 @@ void FullCodeGenerator::EmitKeyedPropertyAssignment(Assignment* expr) {
   }
 
   __ pop(ecx);
-  decrement_stack_height();
   if (expr->ends_initialization_block()) {
     __ mov(edx, Operand(esp, 0));  // Leave receiver on the stack for later.
   } else {
     __ pop(edx);
-    decrement_stack_height();
   }
   // Record source code position before IC call.
   SetSourcePosition(expr->position());
@@ -2036,7 +1979,6 @@ void FullCodeGenerator::EmitKeyedPropertyAssignment(Assignment* expr) {
     __ push(edx);
     __ CallRuntime(Runtime::kToFastProperties, 1);
     __ pop(eax);
-    decrement_stack_height();
   }
 
   PrepareForBailoutForId(expr->AssignmentId(), TOS_REG);
@@ -2056,7 +1998,6 @@ void FullCodeGenerator::VisitProperty(Property* expr) {
     VisitForStackValue(expr->obj());
     VisitForAccumulatorValue(expr->key());
     __ pop(edx);
-    decrement_stack_height();
     EmitKeyedPropertyLoad(expr);
     context()->Plug(eax);
   }
@@ -2083,7 +2024,6 @@ void FullCodeGenerator::EmitCallWithIC(Call* expr,
   RecordJSReturnSite(expr);
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-  decrement_stack_height(arg_count + 1);
   context()->Plug(eax);
 }
 
@@ -2098,7 +2038,6 @@ void FullCodeGenerator::EmitKeyedCallWithIC(Call* expr,
   __ pop(ecx);
   __ push(eax);
   __ push(ecx);
-  increment_stack_height();
 
   // Load the arguments.
   ZoneList<Expression*>* args = expr->arguments();
@@ -2117,7 +2056,6 @@ void FullCodeGenerator::EmitKeyedCallWithIC(Call* expr,
   RecordJSReturnSite(expr);
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-  decrement_stack_height(arg_count + 1);
   context()->DropAndPlug(1, eax);  // Drop the key still on the stack.
 }
 
@@ -2161,8 +2099,6 @@ void FullCodeGenerator::EmitCallWithStub(Call* expr, CallFunctionFlags flags) {
   RecordJSReturnSite(expr);
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-
-  decrement_stack_height(arg_count + 1);
   context()->DropAndPlug(1, eax);
 }
 
@@ -2210,7 +2146,6 @@ void FullCodeGenerator::VisitCall(Call* expr) {
       VisitForStackValue(callee);
       // Reserved receiver slot.
       __ push(Immediate(isolate()->factory()->undefined_value()));
-      increment_stack_height();
       // Push the arguments.
       for (int i = 0; i < arg_count; i++) {
         VisitForStackValue(args->at(i));
@@ -2233,13 +2168,11 @@ void FullCodeGenerator::VisitCall(Call* expr) {
     RecordJSReturnSite(expr);
     // Restore context register.
     __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-    decrement_stack_height(arg_count + 1);  // Function is left on the stack.
     context()->DropAndPlug(1, eax);
 
   } else if (proxy != NULL && proxy->var()->IsUnallocated()) {
     // Push global object as receiver for the call IC.
     __ push(GlobalObjectOperand());
-    increment_stack_height();
     EmitCallWithIC(expr, proxy->name(), RelocInfo::CODE_TARGET_CONTEXT);
 
   } else if (proxy != NULL && proxy->var()->IsLookupSlot()) {
@@ -2258,7 +2191,6 @@ void FullCodeGenerator::VisitCall(Call* expr) {
     __ CallRuntime(Runtime::kLoadContextSlot, 2);
     __ push(eax);  // Function.
     __ push(edx);  // Receiver.
-    increment_stack_height(2);
 
     // If fast case code has been generated, emit code to push the function
     // and receiver and have the slow path jump around this code.
@@ -2266,8 +2198,7 @@ void FullCodeGenerator::VisitCall(Call* expr) {
       Label call;
       __ jmp(&call, Label::kNear);
       __ bind(&done);
-      // Push function.  Stack height already incremented in slow case
-      // above.
+      // Push function.
       __ push(eax);
       // The receiver is implicitly the global receiver. Indicate this by
       // passing the hole to the call function stub.
@@ -2300,7 +2231,6 @@ void FullCodeGenerator::VisitCall(Call* expr) {
     // Load global receiver object.
     __ mov(ebx, GlobalObjectOperand());
     __ push(FieldOperand(ebx, GlobalObject::kGlobalReceiverOffset));
-    increment_stack_height();
     // Emit function call.
     EmitCallWithStub(expr, NO_CALL_FUNCTION_FLAGS);
   }
@@ -2341,8 +2271,6 @@ void FullCodeGenerator::VisitCallNew(CallNew* expr) {
   Handle<Code> construct_builtin =
       isolate()->builtins()->JSConstructCall();
   __ call(construct_builtin, RelocInfo::CONSTRUCT_CALL);
-
-  decrement_stack_height(arg_count + 1);
   context()->Plug(eax);
 }
 
@@ -2655,7 +2583,6 @@ void FullCodeGenerator::EmitObjectEquals(ZoneList<Expression*>* args) {
                          &if_true, &if_false, &fall_through);
 
   __ pop(ebx);
-  decrement_stack_height();
   __ cmp(eax, ebx);
   PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
   Split(equal, if_true, if_false, fall_through);
@@ -2774,7 +2701,6 @@ void FullCodeGenerator::EmitLog(ZoneList<Expression*>* args) {
     VisitForStackValue(args->at(1));
     VisitForStackValue(args->at(2));
     __ CallRuntime(Runtime::kLog, 2);
-    decrement_stack_height(2);
   }
   // Finally, we're expected to leave a value on the top of the stack.
   __ mov(eax, isolate()->factory()->undefined_value());
@@ -2841,7 +2767,6 @@ void FullCodeGenerator::EmitSubString(ZoneList<Expression*>* args) {
   VisitForStackValue(args->at(1));
   VisitForStackValue(args->at(2));
   __ CallStub(&stub);
-  decrement_stack_height(3);
   context()->Plug(eax);
 }
 
@@ -2855,7 +2780,6 @@ void FullCodeGenerator::EmitRegExpExec(ZoneList<Expression*>* args) {
   VisitForStackValue(args->at(2));
   VisitForStackValue(args->at(3));
   __ CallStub(&stub);
-  decrement_stack_height(4);
   context()->Plug(eax);
 }
 
@@ -2890,7 +2814,6 @@ void FullCodeGenerator::EmitMathPow(ZoneList<Expression*>* args) {
   } else {
     __ CallRuntime(Runtime::kMath_pow, 2);
   }
-  decrement_stack_height(2);
   context()->Plug(eax);
 }
 
@@ -2901,7 +2824,6 @@ void FullCodeGenerator::EmitSetValueOf(ZoneList<Expression*>* args) {
   VisitForStackValue(args->at(0));  // Load the object.
   VisitForAccumulatorValue(args->at(1));  // Load the value.
   __ pop(ebx);  // eax = value. ebx = object.
-  decrement_stack_height();
 
   Label done;
   // If the object is a smi, return the value.
@@ -2932,7 +2854,6 @@ void FullCodeGenerator::EmitNumberToString(ZoneList<Expression*>* args) {
 
   NumberToStringStub stub;
   __ CallStub(&stub);
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -2967,7 +2888,6 @@ void FullCodeGenerator::EmitStringCharCodeAt(ZoneList<Expression*>* args) {
   Register result = edx;
 
   __ pop(object);
-  decrement_stack_height();
 
   Label need_conversion;
   Label index_out_of_range;
@@ -3016,7 +2936,6 @@ void FullCodeGenerator::EmitStringCharAt(ZoneList<Expression*>* args) {
   Register result = eax;
 
   __ pop(object);
-  decrement_stack_height();
 
   Label need_conversion;
   Label index_out_of_range;
@@ -3061,7 +2980,6 @@ void FullCodeGenerator::EmitStringAdd(ZoneList<Expression*>* args) {
 
   StringAddStub stub(NO_STRING_ADD_FLAGS);
   __ CallStub(&stub);
-  decrement_stack_height(2);
   context()->Plug(eax);
 }
 
@@ -3074,7 +2992,6 @@ void FullCodeGenerator::EmitStringCompare(ZoneList<Expression*>* args) {
 
   StringCompareStub stub;
   __ CallStub(&stub);
-  decrement_stack_height(2);
   context()->Plug(eax);
 }
 
@@ -3086,7 +3003,6 @@ void FullCodeGenerator::EmitMathSin(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   VisitForStackValue(args->at(0));
   __ CallStub(&stub);
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -3098,7 +3014,6 @@ void FullCodeGenerator::EmitMathCos(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   VisitForStackValue(args->at(0));
   __ CallStub(&stub);
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -3110,7 +3025,6 @@ void FullCodeGenerator::EmitMathLog(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   VisitForStackValue(args->at(0));
   __ CallStub(&stub);
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -3120,7 +3034,6 @@ void FullCodeGenerator::EmitMathSqrt(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   VisitForStackValue(args->at(0));
   __ CallRuntime(Runtime::kMath_sqrt, 1);
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -3140,7 +3053,6 @@ void FullCodeGenerator::EmitCallFunction(ZoneList<Expression*>* args) {
   __ InvokeFunction(edi, count, CALL_FUNCTION,
                     NullCallWrapper(), CALL_AS_METHOD);
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-  decrement_stack_height(arg_count + 1);
   context()->Plug(eax);
 }
 
@@ -3153,7 +3065,6 @@ void FullCodeGenerator::EmitRegExpConstructResult(ZoneList<Expression*>* args) {
   VisitForStackValue(args->at(1));
   VisitForStackValue(args->at(2));
   __ CallStub(&stub);
-  decrement_stack_height(3);
   context()->Plug(eax);
 }
 
@@ -3246,7 +3157,6 @@ void FullCodeGenerator::EmitSwapElements(ZoneList<Expression*>* args) {
   __ CallRuntime(Runtime::kSwapElements, 3);
 
   __ bind(&done);
-  decrement_stack_height(3);
   context()->Plug(eax);
 }
 
@@ -3332,7 +3242,6 @@ void FullCodeGenerator::EmitIsRegExpEquivalent(ZoneList<Expression*>* args) {
   __ mov(eax, Immediate(isolate()->factory()->true_value()));
   __ bind(&done);
 
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -3636,7 +3545,6 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(ZoneList<Expression*>* args) {
   __ add(esp, Immediate(3 * kPointerSize));
 
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-  decrement_stack_height();
   context()->Plug(eax);
 }
 
@@ -3656,7 +3564,6 @@ void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
     // Prepare for calling JS runtime function.
     __ mov(eax, GlobalObjectOperand());
     __ push(FieldOperand(eax, GlobalObject::kBuiltinsOffset));
-    increment_stack_height();
   }
 
   // Push the arguments ("left-to-right").
@@ -3678,11 +3585,6 @@ void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
     // Call the C runtime function.
     __ CallRuntime(expr->function(), arg_count);
   }
-  decrement_stack_height(arg_count);
-  if (expr->is_jsruntime()) {
-    decrement_stack_height();
-  }
-
   context()->Plug(eax);
 }
 
@@ -3699,7 +3601,6 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
         VisitForStackValue(property->key());
         __ push(Immediate(Smi::FromInt(strict_mode_flag())));
         __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
-        decrement_stack_height(2);
         context()->Plug(eax);
       } else if (proxy != NULL) {
         Variable* var = proxy->var();
@@ -3769,7 +3670,6 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
         VisitForTypeofValue(expr->expression());
       }
       __ CallRuntime(Runtime::kTypeof, 1);
-      decrement_stack_height();
       context()->Plug(eax);
       break;
     }
@@ -3823,10 +3723,7 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
   // Invalid left-hand sides are rewritten to have a 'throw ReferenceError'
   // as the left-hand side.
   if (!expr->expression()->IsValidLeftHandSide()) {
-    ASSERT(expr->expression()->AsThrow() != NULL);
-    VisitInCurrentContext(expr->expression());
-    // Visiting Throw does not plug the context.
-    context()->Plug(eax);
+    VisitForEffect(expr->expression());
     return;
   }
 
@@ -3851,20 +3748,17 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
     // Reserve space for result of postfix operation.
     if (expr->is_postfix() && !context()->IsEffect()) {
       __ push(Immediate(Smi::FromInt(0)));
-      increment_stack_height();
     }
     if (assign_type == NAMED_PROPERTY) {
       // Put the object both on the stack and in the accumulator.
       VisitForAccumulatorValue(prop->obj());
       __ push(eax);
-      increment_stack_height();
       EmitNamedPropertyLoad(prop);
     } else {
       VisitForStackValue(prop->obj());
       VisitForAccumulatorValue(prop->key());
       __ mov(edx, Operand(esp, 0));
       __ push(eax);
-      increment_stack_height();
       EmitKeyedPropertyLoad(prop);
     }
   }
@@ -3895,7 +3789,6 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
       switch (assign_type) {
         case VARIABLE:
           __ push(eax);
-          increment_stack_height();
           break;
         case NAMED_PROPERTY:
           __ mov(Operand(esp, kPointerSize), eax);
@@ -3969,7 +3862,6 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
     case NAMED_PROPERTY: {
       __ mov(ecx, prop->key()->AsLiteral()->handle());
       __ pop(edx);
-      decrement_stack_height();
       Handle<Code> ic = is_strict_mode()
           ? isolate()->builtins()->StoreIC_Initialize_Strict()
           : isolate()->builtins()->StoreIC_Initialize();
@@ -3987,8 +3879,6 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
     case KEYED_PROPERTY: {
       __ pop(ecx);
       __ pop(edx);
-      decrement_stack_height();
-      decrement_stack_height();
       Handle<Code> ic = is_strict_mode()
           ? isolate()->builtins()->KeyedStoreIC_Initialize_Strict()
           : isolate()->builtins()->KeyedStoreIC_Initialize();
@@ -4141,7 +4031,6 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
     case Token::IN:
       VisitForStackValue(expr->right());
       __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION);
-      decrement_stack_height(2);
       PrepareForBailoutBeforeSplit(TOS_REG, false, NULL, NULL);
       __ cmp(eax, isolate()->factory()->true_value());
       Split(equal, if_true, if_false, fall_through);
@@ -4151,7 +4040,6 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
       VisitForStackValue(expr->right());
       InstanceofStub stub(InstanceofStub::kNoFlags);
       __ CallStub(&stub);
-      decrement_stack_height(2);
       PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
       __ test(eax, eax);
       // The stub returns 0 for true.
@@ -4185,7 +4073,6 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
           UNREACHABLE();
       }
       __ pop(edx);
-      decrement_stack_height();
 
       bool inline_smi_code = ShouldInlineSmiCase(op);
       JumpPatchSite patch_site(masm_);