[fullcodegen] Implement operand stack depth tracking.

src/full-codegen/full-codegen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/full-codegen/full-codegen.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/ast-numbering.h"
 #include "src/ast/prettyprinter.h"
 #include "src/ast/scopeinfo.h"
@@ skipping 259 matching lines @@
 void FullCodeGenerator::EffectContext::Plug(Register reg) const {
 }
 
 
 void FullCodeGenerator::AccumulatorValueContext::Plug(Register reg) const {
   __ Move(result_register(), reg);
 }
 
 
 void FullCodeGenerator::StackValueContext::Plug(Register reg) const {
+  codegen()->OperandStackDepthIncrement(1);

[Jarin, 2016/02/19 06:52:04]

Could not you call codegen()->PushOperand here?

(And similarly DropOperands, PopOperand below?)

[Michael Starzinger, 2016/02/19 09:24:04]

Done. Here and below.

   __ Push(reg);
 }
 
 
 void FullCodeGenerator::TestContext::Plug(Register reg) const {
   // For simplicity we always test the accumulator register.
   __ Move(result_register(), reg);
   codegen()->PrepareForBailoutBeforeSplit(condition(), false, NULL, NULL);
   codegen()->DoTest(this);
 }
 
 
 void FullCodeGenerator::EffectContext::Plug(bool flag) const {}
 
 
 void FullCodeGenerator::EffectContext::PlugTOS() const {
+  codegen()->OperandStackDepthDecrement(1);
   __ Drop(1);
 }
 
 
 void FullCodeGenerator::AccumulatorValueContext::PlugTOS() const {
+  codegen()->OperandStackDepthDecrement(1);
   __ Pop(result_register());
 }
 
 
 void FullCodeGenerator::StackValueContext::PlugTOS() const {
 }
 
 
 void FullCodeGenerator::TestContext::PlugTOS() const {
+  codegen()->OperandStackDepthDecrement(1);
   // For simplicity we always test the accumulator register.
   __ Pop(result_register());
   codegen()->PrepareForBailoutBeforeSplit(condition(), false, NULL, NULL);
   codegen()->DoTest(this);
 }
 
 
 void FullCodeGenerator::EffectContext::PrepareTest(
     Label* materialize_true,
     Label* materialize_false,
@@ skipping 111 matching lines @@
 }
 
 
 int FullCodeGenerator::DeclareGlobalsFlags() {
   DCHECK(DeclareGlobalsLanguageMode::is_valid(language_mode()));
   return DeclareGlobalsEvalFlag::encode(is_eval()) |
          DeclareGlobalsNativeFlag::encode(is_native()) |
          DeclareGlobalsLanguageMode::encode(language_mode());
 }
 
+void FullCodeGenerator::PushOperand(MemOperand operand) {
+  OperandStackDepthIncrement(1);
+  __ Push(operand);
+}
+
+void FullCodeGenerator::PushOperand(Handle<Object> handle) {
+  OperandStackDepthIncrement(1);
+  __ Push(handle);
+}
+
+void FullCodeGenerator::PushOperand(Smi* smi) {
+  OperandStackDepthIncrement(1);
+  __ Push(smi);
+}
+
+void FullCodeGenerator::PushOperand(Register reg) {
+  OperandStackDepthIncrement(1);
+  __ Push(reg);
+}
+
+void FullCodeGenerator::PopOperand(Register reg) {
+  OperandStackDepthDecrement(1);
+  __ Pop(reg);
+}
+
+void FullCodeGenerator::DropOperands(int count) {
+  OperandStackDepthDecrement(count);
+  __ Drop(count);
+}
+
+void FullCodeGenerator::CallRuntimeWithOperands(Runtime::FunctionId id) {
+  OperandStackDepthDecrement(Runtime::FunctionForId(id)->nargs);
+  __ CallRuntime(id);
+}
+
+void FullCodeGenerator::OperandStackDepthIncrement(int count) {
+  DCHECK_GE(operand_stack_depth_, 0);
+  operand_stack_depth_ += count;
+}
+
+void FullCodeGenerator::OperandStackDepthDecrement(int count) {
+  DCHECK_GE(operand_stack_depth_, count);
+  operand_stack_depth_ -= count;
+}
 
 void FullCodeGenerator::EmitSubString(CallRuntime* expr) {
   // Load the arguments on the stack and call the stub.
   SubStringStub stub(isolate());
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 3);
   VisitForStackValue(args->at(0));
   VisitForStackValue(args->at(1));
   VisitForStackValue(args->at(2));
   __ CallStub(&stub);
+  OperandStackDepthDecrement(3);
   context()->Plug(result_register());
 }
 
 
 void FullCodeGenerator::EmitRegExpExec(CallRuntime* expr) {
   // Load the arguments on the stack and call the stub.
   RegExpExecStub stub(isolate());
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 4);
   VisitForStackValue(args->at(0));
   VisitForStackValue(args->at(1));
   VisitForStackValue(args->at(2));
   VisitForStackValue(args->at(3));
   __ CallStub(&stub);
+  OperandStackDepthDecrement(4);
   context()->Plug(result_register());
 }
 
 
 void FullCodeGenerator::EmitMathPow(CallRuntime* expr) {
   // Load the arguments on the stack and call the runtime function.
+  MathPowStub stub(isolate(), MathPowStub::ON_STACK);
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 2);
   VisitForStackValue(args->at(0));
   VisitForStackValue(args->at(1));
-
-  MathPowStub stub(isolate(), MathPowStub::ON_STACK);
   __ CallStub(&stub);
+  OperandStackDepthDecrement(2);
   context()->Plug(result_register());
 }
 
 
 void FullCodeGenerator::EmitIntrinsicAsStubCall(CallRuntime* expr,
                                                 const Callable& callable) {
   ZoneList<Expression*>* args = expr->arguments();
   int param_count = callable.descriptor().GetRegisterParameterCount();
   DCHECK_EQ(args->length(), param_count);
 
   if (param_count > 0) {
     int last = param_count - 1;
     // Put all but last arguments on stack.
     for (int i = 0; i < last; i++) {
       VisitForStackValue(args->at(i));
     }
     // The last argument goes to the accumulator.
     VisitForAccumulatorValue(args->at(last));
 
     // Move the arguments to the registers, as required by the stub.
     __ Move(callable.descriptor().GetRegisterParameter(last),
             result_register());
     for (int i = last; i-- > 0;) {
-      __ Pop(callable.descriptor().GetRegisterParameter(i));
+      PopOperand(callable.descriptor().GetRegisterParameter(i));
     }
   }
   __ Call(callable.code(), RelocInfo::CODE_TARGET);
   context()->Plug(result_register());
 }
 
 
 void FullCodeGenerator::EmitNumberToString(CallRuntime* expr) {
   EmitIntrinsicAsStubCall(expr, CodeFactory::NumberToString(isolate()));
 }
@@ skipping 433 matching lines @@
     current = current->Exit(&stack_depth, &context_length);
   }
   __ Drop(stack_depth);
   EmitReturnSequence();
 }
 
 
 void FullCodeGenerator::EmitPropertyKey(ObjectLiteralProperty* property,
                                         BailoutId bailout_id) {
   VisitForStackValue(property->key());
-  __ CallRuntime(Runtime::kToName);
+  CallRuntimeWithOperands(Runtime::kToName);
   PrepareForBailoutForId(bailout_id, NO_REGISTERS);
-  __ Push(result_register());
+  PushOperand(result_register());
 }
 
 
 void FullCodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
   Comment cmnt(masm_, "[ ReturnStatement");
   SetStatementPosition(stmt);
   Expression* expr = stmt->expression();
   VisitForAccumulatorValue(expr);
   EmitUnwindAndReturn();
 }
 
 
 void FullCodeGenerator::VisitWithStatement(WithStatement* stmt) {
   Comment cmnt(masm_, "[ WithStatement");
   SetStatementPosition(stmt);
 
   VisitForAccumulatorValue(stmt->expression());
   Callable callable = CodeFactory::ToObject(isolate());
   __ Move(callable.descriptor().GetRegisterParameter(0), result_register());
   __ Call(callable.code(), RelocInfo::CODE_TARGET);
   PrepareForBailoutForId(stmt->ToObjectId(), NO_REGISTERS);
-  __ Push(result_register());
+  PushOperand(result_register());
   PushFunctionArgumentForContextAllocation();
-  __ CallRuntime(Runtime::kPushWithContext);
+  CallRuntimeWithOperands(Runtime::kPushWithContext);
   StoreToFrameField(StandardFrameConstants::kContextOffset, context_register());
   PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
 
   Scope* saved_scope = scope();
   scope_ = stmt->scope();
   { WithOrCatch body(this);
     Visit(stmt->statement());
   }
   scope_ = saved_scope;
 
@@ skipping 172 matching lines @@
   // result register.
 
   Label try_entry, handler_entry, exit;
   __ jmp(&try_entry);
   __ bind(&handler_entry);
   ClearPendingMessage();
 
   // Exception handler code, the exception is in the result register.
   // Extend the context before executing the catch block.
   { Comment cmnt(masm_, "[ Extend catch context");
-    __ Push(stmt->variable()->name());
-    __ Push(result_register());
+    PushOperand(stmt->variable()->name());
+    PushOperand(result_register());
     PushFunctionArgumentForContextAllocation();
-    __ CallRuntime(Runtime::kPushCatchContext);
+    CallRuntimeWithOperands(Runtime::kPushCatchContext);
     StoreToFrameField(StandardFrameConstants::kContextOffset,
                       context_register());
   }
 
   Scope* saved_scope = scope();
   scope_ = stmt->scope();
   DCHECK(scope_->declarations()->is_empty());
   { WithOrCatch catch_body(this);
     Visit(stmt->catch_block());
   }
@@ skipping 67 matching lines @@
   // value in the result register with one that's safe for GC because the
   // finally block will unconditionally preserve the result register on the
   // stack.
   ClearAccumulator();
   deferred.EmitFallThrough();
   // Fall through to the finally block.
 
   // Finally block implementation.
   __ bind(&finally_entry);
   Comment cmnt_finally(masm(), "[ Finally block");
+  OperandStackDepthIncrement(2);  // Token and accumulator are on stack.
   EnterFinallyBlock();
   {
     Finally finally_body(this);
     Visit(stmt->finally_block());
   }
-  ExitFinallyBlock();  // Return to the calling code.
+  ExitFinallyBlock();
+  OperandStackDepthDecrement(2);  // Token and accumulator are on stack.

[Jarin, 2016/02/19 06:52:04]

Nit: are -> were

[Michael Starzinger, 2016/02/19 09:24:04]

Done.

 
   {
     Comment cmnt_deferred(masm(), "[ Post-finally dispatch");
-    deferred.EmitCommands();
+    deferred.EmitCommands();  // Return to the calling code.
   }
 }
 
 
 void FullCodeGenerator::VisitDebuggerStatement(DebuggerStatement* stmt) {
   Comment cmnt(masm_, "[ DebuggerStatement");
   SetStatementPosition(stmt);
 
   __ DebugBreak();
   // Ignore the return value.
 
   PrepareForBailoutForId(stmt->DebugBreakId(), NO_REGISTERS);
 }
 
 
 void FullCodeGenerator::VisitCaseClause(CaseClause* clause) {
   UNREACHABLE();
 }
 
 
 void FullCodeGenerator::VisitConditional(Conditional* expr) {
   Comment cmnt(masm_, "[ Conditional");
   Label true_case, false_case, done;
   VisitForControl(expr->condition(), &true_case, &false_case, &true_case);
 
+  int original_stack_depth = operand_stack_depth_;
   PrepareForBailoutForId(expr->ThenId(), NO_REGISTERS);
   __ bind(&true_case);
   SetExpressionPosition(expr->then_expression());
   if (context()->IsTest()) {
     const TestContext* for_test = TestContext::cast(context());
     VisitForControl(expr->then_expression(),
                     for_test->true_label(),
                     for_test->false_label(),
                     NULL);
   } else {
     VisitInDuplicateContext(expr->then_expression());
     __ jmp(&done);
   }
 
+  operand_stack_depth_ = original_stack_depth;
   PrepareForBailoutForId(expr->ElseId(), NO_REGISTERS);
   __ bind(&false_case);
   SetExpressionPosition(expr->else_expression());
   VisitInDuplicateContext(expr->else_expression());
   // If control flow falls through Visit, merge it with true case here.
   if (!context()->IsTest()) {
     __ bind(&done);
   }
 }
 
@@ skipping 21 matching lines @@
 void FullCodeGenerator::VisitClassLiteral(ClassLiteral* lit) {
   Comment cmnt(masm_, "[ ClassLiteral");
 
   {
     EnterBlockScopeIfNeeded block_scope_state(
         this, lit->scope(), lit->EntryId(), lit->DeclsId(), lit->ExitId());
 
     if (lit->extends() != NULL) {
       VisitForStackValue(lit->extends());
     } else {
-      __ Push(isolate()->factory()->the_hole_value());
+      PushOperand(isolate()->factory()->the_hole_value());
     }
 
     VisitForStackValue(lit->constructor());
 
-    __ Push(Smi::FromInt(lit->start_position()));
-    __ Push(Smi::FromInt(lit->end_position()));
+    PushOperand(Smi::FromInt(lit->start_position()));
+    PushOperand(Smi::FromInt(lit->end_position()));
 
-    __ CallRuntime(Runtime::kDefineClass);
+    CallRuntimeWithOperands(Runtime::kDefineClass);
     PrepareForBailoutForId(lit->CreateLiteralId(), TOS_REG);
-    __ Push(result_register());
+    PushOperand(result_register());
 
     // Load the "prototype" from the constructor.
     __ Move(LoadDescriptor::ReceiverRegister(), result_register());
     __ LoadRoot(LoadDescriptor::NameRegister(),
                 Heap::kprototype_stringRootIndex);
     __ Move(LoadDescriptor::SlotRegister(), SmiFromSlot(lit->PrototypeSlot()));
     CallLoadIC(NOT_INSIDE_TYPEOF);
     PrepareForBailoutForId(lit->PrototypeId(), TOS_REG);
-    __ Push(result_register());
+    PushOperand(result_register());
 
     EmitClassDefineProperties(lit);
 
     // Set both the prototype and constructor to have fast properties, and also
     // freeze them in strong mode.
-    __ CallRuntime(Runtime::kFinalizeClassDefinition);
+    CallRuntimeWithOperands(Runtime::kFinalizeClassDefinition);
 
     if (lit->class_variable_proxy() != nullptr) {
       EmitVariableAssignment(lit->class_variable_proxy()->var(), Token::INIT,
                              lit->ProxySlot());
     }
   }
 
   context()->Plug(result_register());
 }
 
 
 void FullCodeGenerator::VisitNativeFunctionLiteral(
     NativeFunctionLiteral* expr) {
   Comment cmnt(masm_, "[ NativeFunctionLiteral");
   Handle<SharedFunctionInfo> shared =
       Compiler::GetSharedFunctionInfoForNative(expr->extension(), expr->name());
   EmitNewClosure(shared, false);
 }
 
 
 void FullCodeGenerator::VisitThrow(Throw* expr) {
   Comment cmnt(masm_, "[ Throw");
   VisitForStackValue(expr->exception());
   SetExpressionPosition(expr);
-  __ CallRuntime(Runtime::kThrow);
+  CallRuntimeWithOperands(Runtime::kThrow);
   // Never returns here.
+
+  // Even though this expression doesn't produce a value, we need to simulate
+  // plugging of the value context to ensure stack depth tracking is in sync.
+  if (context()->IsStackValue()) OperandStackDepthIncrement(1);
 }
 
 
 void FullCodeGenerator::EnterTryBlock(int handler_index, Label* handler) {
   HandlerTableEntry* entry = &handler_table_[handler_index];
   entry->range_start = masm()->pc_offset();
   entry->handler_offset = handler->pos();
   entry->try_catch_depth = try_catch_depth_;
+  entry->stack_depth = operand_stack_depth_;
 
-  // Determine expression stack depth of try statement.
-  int stack_depth = info_->scope()->num_stack_slots();  // Include stack locals.
-  for (NestedStatement* current = nesting_stack_; current != NULL; /*nop*/) {
-    current = current->AccumulateDepth(&stack_depth);
-  }
-  entry->stack_depth = stack_depth;
+  // We are using the operand stack depth, check for accuracy.
+  EmitOperandStackDepthCheck();
 
   // Push context onto operand stack.
   STATIC_ASSERT(TryBlockConstant::kElementCount == 1);
-  __ Push(context_register());
+  PushOperand(context_register());
 }
 
 
 void FullCodeGenerator::ExitTryBlock(int handler_index) {
   HandlerTableEntry* entry = &handler_table_[handler_index];
   entry->range_end = masm()->pc_offset();
 
   // Drop context from operand stack.
-  __ Drop(TryBlockConstant::kElementCount);
+  DropOperands(TryBlockConstant::kElementCount);
 }
 
 
 void FullCodeGenerator::VisitCall(Call* expr) {
 #ifdef DEBUG
   // We want to verify that RecordJSReturnSite gets called on all paths
   // through this function.  Avoid early returns.
   expr->return_is_recorded_ = false;
 #endif
 
@@ skipping 32 matching lines @@
       break;
     case Call::KEYED_SUPER_PROPERTY_CALL:
       EmitKeyedSuperCallWithLoadIC(expr);
       break;
     case Call::SUPER_CALL:
       EmitSuperConstructorCall(expr);
       break;
     case Call::OTHER_CALL:
       // Call to an arbitrary expression not handled specially above.
       VisitForStackValue(callee);
+      OperandStackDepthIncrement(1);
       __ PushRoot(Heap::kUndefinedValueRootIndex);
       // Emit function call.
       EmitCall(expr);
       break;
   }
 
 #ifdef DEBUG
   // RecordJSReturnSite should have been called.
   DCHECK(expr->return_is_recorded_);
 #endif
@@ skipping 196 matching lines @@
 
   if (scope == NULL) {
     codegen_->PrepareForBailoutForId(entry_id, NO_REGISTERS);
     needs_block_context_ = false;
   } else {
     needs_block_context_ = scope->NeedsContext();
     codegen_->scope_ = scope;
     {
       if (needs_block_context_) {
         Comment cmnt(masm(), "[ Extend block context");
-        __ Push(scope->GetScopeInfo(codegen->isolate()));
+        codegen_->PushOperand(scope->GetScopeInfo(codegen->isolate()));
         codegen_->PushFunctionArgumentForContextAllocation();
-        __ CallRuntime(Runtime::kPushBlockContext);
+        codegen_->CallRuntimeWithOperands(Runtime::kPushBlockContext);
 
         // Replace the context stored in the frame.
         codegen_->StoreToFrameField(StandardFrameConstants::kContextOffset,
                                     codegen_->context_register());
       }
       CHECK_EQ(0, scope->num_stack_slots());
       codegen_->PrepareForBailoutForId(entry_id, NO_REGISTERS);
     }
     {
       Comment cmnt(masm(), "[ Declarations");
@@ skipping 74 matching lines @@
   return var->mode() == CONST_LEGACY || var->scope()->is_nonlinear() ||
          var->initializer_position() >= proxy->position();
 }
 
 
 #undef __
 
 
 }  // namespace internal
 }  // namespace v8