Add tracing of the stack height to full code generator.

BUG=
TEST=

Review URL: http://codereview.chromium.org/7097011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8755 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/flag-definitions.h

@@ -400,6 +400,7 @@ 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")

src/full-codegen.cc

@@ -437,6 +437,7 @@ void FullCodeGenerator::AccumulatorValueContext::Plug(Register reg) const {
 
 void FullCodeGenerator::StackValueContext::Plug(Register reg) const {
   __ push(reg);
+  codegen()->increment_stack_height();
 }
 
 
@@ -450,11 +451,13 @@ 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();
 }
 
 
@@ -465,6 +468,7 @@ 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);
 }
@@ -960,6 +964,7 @@ void FullCodeGenerator::VisitEnterWithContextStatement(
   VisitForStackValue(stmt->expression());
   PushFunctionArgumentForContextAllocation();
   __ CallRuntime(Runtime::kPushWithContext, 2);
+  decrement_stack_height();
   StoreToFrameField(StandardFrameConstants::kContextOffset, context_register());
 }
 
@@ -1128,8 +1133,10 @@ void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   {
     TryCatch try_block(this, &catch_entry);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_CATCH_HANDLER);
+    increment_stack_height(StackHandlerConstants::kSize / kPointerSize);
     Visit(stmt->try_block());
     __ PopTryHandler();
+    decrement_stack_height(StackHandlerConstants::kSize / kPointerSize);
   }
   __ bind(&done);
 }
@@ -1161,6 +1168,10 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   // cooked before GC.
   Label finally_entry;
   Label try_handler_setup;
+  const int original_stack_height = stack_height();
+  const int finally_block_stack_height = original_stack_height + 2;
+  const int try_block_stack_height = original_stack_height + 4;
+  STATIC_ASSERT(StackHandlerConstants::kSize / kPointerSize == 4);
 
   // Setup the try-handler chain. Use a call to
   // Jump to try-handler setup and try-block code. Use call to put try-handler
@@ -1182,6 +1193,7 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
     // Finally block implementation.
     Finally finally_block(this);
     EnterFinallyBlock();
+    set_stack_height(finally_block_stack_height);
     Visit(stmt->finally_block());
     ExitFinallyBlock();  // Return to the calling code.
   }
@@ -1191,8 +1203,10 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
     // Setup try handler (stack pointer registers).
     TryFinally try_block(this, &finally_entry);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_FINALLY_HANDLER);
+    set_stack_height(try_block_stack_height);
     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
@@ -1222,6 +1236,7 @@ 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(),
@@ -1235,6 +1250,7 @@ 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());
@@ -1275,8 +1291,11 @@ 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.
 }
 

src/full-codegen.h

@@ -83,6 +83,7 @@ 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.
@@ -519,6 +520,35 @@ 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;
@@ -578,6 +608,10 @@ 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(); }
@@ -631,6 +665,7 @@ 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_;
@@ -640,7 +675,9 @@ class FullCodeGenerator: public AstVisitor {
   class AccumulatorValueContext : public ExpressionContext {
    public:
     explicit AccumulatorValueContext(FullCodeGenerator* codegen)
-        : ExpressionContext(codegen) { }
+        : ExpressionContext(codegen) {
+      expected_stack_height_ = codegen->stack_height();
+    }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
@@ -661,7 +698,9 @@ class FullCodeGenerator: public AstVisitor {
   class StackValueContext : public ExpressionContext {
    public:
     explicit StackValueContext(FullCodeGenerator* codegen)
-        : ExpressionContext(codegen) { }
+        : ExpressionContext(codegen) {
+      expected_stack_height_ = codegen->stack_height() + 1;
+    }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
@@ -690,7 +729,9 @@ class FullCodeGenerator: public AstVisitor {
           condition_(condition),
           true_label_(true_label),
           false_label_(false_label),
-          fall_through_(fall_through) { }
+          fall_through_(fall_through) {
+      expected_stack_height_ = codegen->stack_height();
+    }
 
     static const TestContext* cast(const ExpressionContext* context) {
       ASSERT(context->IsTest());
@@ -727,7 +768,10 @@ class FullCodeGenerator: public AstVisitor {
   class EffectContext : public ExpressionContext {
    public:
     explicit EffectContext(FullCodeGenerator* codegen)
-        : ExpressionContext(codegen) { }
+        : ExpressionContext(codegen) {
+      expected_stack_height_ = codegen->stack_height();
+    }
+
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
@@ -751,6 +795,7 @@ 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_;