[interpreter] First implementation of stack unwinding.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 899 matching lines @@
   // that is intercepting 'throw' control commands.
   try_control_builder.BeginTry(context);
   // TODO(mstarzinger): Control scope is missing!
   Visit(stmt->try_block());
   try_control_builder.EndTry();
 
   // Clear message object as we enter the catch block.
   // TODO(mstarzinger): Implement this!
 
   // Create a catch scope that binds the exception.
-  register_allocator()->PrepareForConsecutiveAllocations(3);
-  Register name = register_allocator()->NextConsecutiveRegister();
-  Register exception = register_allocator()->NextConsecutiveRegister();
-  Register closure = register_allocator()->NextConsecutiveRegister();
-  builder()
-      ->StoreAccumulatorInRegister(exception)
-      .LoadLiteral(stmt->variable()->name())
-      .StoreAccumulatorInRegister(name);
-  VisitFunctionClosureForContext();
-  builder()->StoreAccumulatorInRegister(closure).CallRuntime(
-      Runtime::kPushCatchContext, name, 3);
+  VisitNewLocalCatchContext(stmt->variable());
 
   // Evaluate the catch-block.
-  Visit(stmt->catch_block());
+  VisitInScope(stmt->catch_block(), stmt->scope());
   try_control_builder.EndCatch();
 }
 
 
 void BytecodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   TryFinallyBuilder try_control_builder(builder());
 
   // Preserve the context in a dedicated register, so that it can be restored
   // when the handler is entered by the stack-unwinding machinery.
   // TODO(mstarzinger): Be smarter about register allocation.
@@ skipping 1177 matching lines @@
       ->LoadLiteral(scope->GetScopeInfo(isolate()))
       .StoreAccumulatorInRegister(scope_info);
   VisitFunctionClosureForContext();
   builder()
       ->StoreAccumulatorInRegister(closure)
       .CallRuntime(Runtime::kPushBlockContext, scope_info, 2);
   execution_result()->SetResultInAccumulator();
 }
 
 
+void BytecodeGenerator::VisitNewLocalCatchContext(Variable* variable) {
+  AccumulatorResultScope accumulator_execution_result(this);
+  DCHECK(variable->IsContextSlot());
+
+  // Allocate a new local block context.
+  register_allocator()->PrepareForConsecutiveAllocations(3);
+  Register name = register_allocator()->NextConsecutiveRegister();
+  Register exception = register_allocator()->NextConsecutiveRegister();
+  Register closure = register_allocator()->NextConsecutiveRegister();
+
+  builder()
+      ->StoreAccumulatorInRegister(exception)
+      .LoadLiteral(variable->name())
+      .StoreAccumulatorInRegister(name);
+  VisitFunctionClosureForContext();
+  builder()->StoreAccumulatorInRegister(closure).CallRuntime(
+      Runtime::kPushCatchContext, name, 3);
+  execution_result()->SetResultInAccumulator();
+}
+
+
 void BytecodeGenerator::VisitObjectLiteralAccessor(
     Register home_object, ObjectLiteralProperty* property, Register value_out) {
   // TODO(rmcilroy): Replace value_out with VisitForRegister();
   if (property == nullptr) {
     builder()->LoadNull().StoreAccumulatorInRegister(value_out);
   } else {
     VisitForAccumulatorValue(property->value());
     builder()->StoreAccumulatorInRegister(value_out);
     VisitSetHomeObject(value_out, home_object, property);
   }
@@ skipping 84 matching lines @@
 
 // Visits the expression |expr| and returns the register containing
 // the expression result.
 Register BytecodeGenerator::VisitForRegisterValue(Expression* expr) {
   RegisterResultScope register_scope(this);
   Visit(expr);
   return register_scope.ResultRegister();
 }
 
 
+void BytecodeGenerator::VisitInScope(Statement* stmt, Scope* scope) {
+  ContextScope context_scope(this, scope);
+  DCHECK(scope->declarations()->is_empty());
+  Visit(stmt);
+}
+
+
 Register BytecodeGenerator::NextContextRegister() const {
   if (execution_context() == nullptr) {
     // Return the incoming function context for the outermost execution context.
     return Register::function_context();
   }
   Register previous = execution_context()->reg();
   if (previous == Register::function_context()) {
     // If the previous context was the incoming function context, then the next
     // context register is the first local context register.
     return builder_.first_context_register();
@@ skipping 15 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8