[interpreter] Switch context during 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 1096 matching lines @@
 
 
 void BytecodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   TryCatchBuilder try_control_builder(builder());
   Register no_reg;
 
   // 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.
   Register context = register_allocator()->NewRegister();
+  builder()->MoveRegister(Register::current_context(), context);
 
   // Evaluate the try-block inside a control scope. This simulates a handler
   // that is intercepting 'throw' control commands.
   try_control_builder.BeginTry(context);
   {
     ControlScopeForTryCatch scope(this, &try_control_builder);
     Visit(stmt->try_block());
   }
   try_control_builder.EndTry();
 
@@ skipping 33 matching lines @@
   //  - BreakStatement/ContinueStatement: Undefined and not used.
   //  - Falling through into finally-block: Undefined and not used.
   Register token = register_allocator()->NewRegister();
   Register result = register_allocator()->NewRegister();
   ControlScope::DeferredCommands commands(this, token, result);
 
   // 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.
   Register context = register_allocator()->NewRegister();
+  builder()->MoveRegister(Register::current_context(), context);
 
   // Evaluate the try-block inside a control scope. This simulates a handler
   // that is intercepting all control commands.
   try_control_builder.BeginTry(context);
   {
     ControlScopeForTryFinally scope(this, &try_control_builder, &commands);
     Visit(stmt->try_block());
   }
   try_control_builder.EndTry();
 
@@ skipping 1340 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8