[turbofan] Fix exception being re-thrown after finally-block.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/linkage.h"
@@ skipping 194 matching lines @@
 // paths going through the finally-block to dispatch after leaving the block.
 class AstGraphBuilder::ControlScope::DeferredCommands : public ZoneObject {
  public:
   explicit DeferredCommands(AstGraphBuilder* owner)
       : owner_(owner), deferred_(owner->zone()) {}
 
   // One recorded control-flow command.
   struct Entry {
     Command command;       // The command type being applied on this path.
     Statement* statement;  // The target statement for the command or {NULL}.
-    Node* value;           // The passed value node for the command or {NULL}.
     Node* token;           // A token identifying this particular path.
   };
 
   // Records a control-flow command while entering the finally-block. This also
   // generates a new dispatch token that identifies one particular path.
   Node* RecordCommand(Command cmd, Statement* stmt, Node* value) {
     Node* token = NewPathTokenForDeferredCommand();
-    deferred_.push_back({cmd, stmt, value, token});
+    deferred_.push_back({cmd, stmt, token});
     return token;
   }
 
   // Returns the dispatch token to be used to identify the implicit fall-through
   // path at the end of a try-block into the corresponding finally-block.
   Node* GetFallThroughToken() { return NewPathTokenForImplicitFallThrough(); }
 
   // Applies all recorded control-flow commands after the finally-block again.
   // This generates a dynamic dispatch on the token from the entry point.
-  void ApplyDeferredCommands(Node* token) {
+  void ApplyDeferredCommands(Node* token, Node* value) {
     SwitchBuilder dispatch(owner_, static_cast<int>(deferred_.size()));
     dispatch.BeginSwitch();
     for (size_t i = 0; i < deferred_.size(); ++i) {
       Node* condition = NewPathDispatchCondition(token, deferred_[i].token);
       dispatch.BeginLabel(static_cast<int>(i), condition);
       dispatch.EndLabel();
     }
     for (size_t i = 0; i < deferred_.size(); ++i) {
       dispatch.BeginCase(static_cast<int>(i));
       owner_->execution_control()->PerformCommand(
-          deferred_[i].command, deferred_[i].statement, deferred_[i].value);
+          deferred_[i].command, deferred_[i].statement, value);
       dispatch.EndCase();
     }
     dispatch.EndSwitch();
   }
 
  protected:
   Node* NewPathTokenForDeferredCommand() {
     return owner_->jsgraph()->Constant(static_cast<int>(deferred_.size()));
   }
   Node* NewPathTokenForImplicitFallThrough() {
@@ skipping 107 matching lines @@
       : ControlScope(owner), commands_(commands), control_(control) {
     builder()->try_nesting_level_++;  // Increment nesting.
   }
   ~ControlScopeForFinally() {
     builder()->try_nesting_level_--;  // Decrement nesting.
   }
 
  protected:
   virtual bool Execute(Command cmd, Statement* target, Node* value) OVERRIDE {
     Node* token = commands_->RecordCommand(cmd, target, value);
-    control_->LeaveTry(token);
+    control_->LeaveTry(token, value);
     return true;
   }
 
  private:
   DeferredCommands* commands_;
   TryFinallyBuilder* control_;
 };
 
 
 AstGraphBuilder::AstGraphBuilder(Zone* local_zone, CompilationInfo* info,
@@ skipping 329 matching lines @@
     environment()->Trim(current->stack_height());
     if (current->Execute(command, target, value)) break;
     current = current->outer_;
   }
   builder()->set_environment(env);
   DCHECK(current != NULL);  // Always handled (unless stack is malformed).
 }
 
 
 void AstGraphBuilder::ControlScope::BreakTo(BreakableStatement* stmt) {
-  PerformCommand(CMD_BREAK, stmt, nullptr);
+  PerformCommand(CMD_BREAK, stmt, builder()->jsgraph()->TheHoleConstant());
 }
 
 
 void AstGraphBuilder::ControlScope::ContinueTo(BreakableStatement* stmt) {
-  PerformCommand(CMD_CONTINUE, stmt, nullptr);
+  PerformCommand(CMD_CONTINUE, stmt, builder()->jsgraph()->TheHoleConstant());
 }
 
 
 void AstGraphBuilder::ControlScope::ReturnValue(Node* return_value) {
   PerformCommand(CMD_RETURN, nullptr, return_value);
 }
 
 
 void AstGraphBuilder::ControlScope::ThrowValue(Node* exception_value) {
   PerformCommand(CMD_THROW, nullptr, exception_value);
@@ skipping 517 matching lines @@
 
   // We keep a record of all paths that enter the finally-block to be able to
   // dispatch to the correct continuation point after the statements in the
   // finally-block have been evaluated.
   //
   // The try-finally construct can enter the finally-block in three ways:
   // 1. By exiting the try-block normally, falling through at the end.
   // 2. By exiting the try-block with a function-local control flow transfer
   //    (i.e. through break/continue/return statements).
   // 3. By exiting the try-block with a thrown exception.
+  Node* fallthrough_result = jsgraph()->TheHoleConstant();
   ControlScope::DeferredCommands* commands =
       new (zone()) ControlScope::DeferredCommands(this);
 
   // Evaluate the try-block inside a control scope. This simulates a handler
   // that is intercepting all control commands.
   try_control.BeginTry();
   {
     ControlScopeForFinally scope(this, commands, &try_control);
     Visit(stmt->try_block());
   }
-  try_control.EndTry(commands->GetFallThroughToken());
+  try_control.EndTry(commands->GetFallThroughToken(), fallthrough_result);
+
+  // The result value semantics depend on how the block was entered:
+  //  - ReturnStatement: It represents the return value being returned.
+  //  - ThrowStatement: It represents the exception being thrown.
+  //  - BreakStatement/ContinueStatement: Filled with the hole.
+  //  - Falling through into finally-block: Filled with the hole.
+  Node* result = try_control.GetResultValueNode();
+
+  // TODO(mstarzinger): See FullCodeGenerator::EnterFinallyBlock.
+  environment()->Push(jsgraph()->SmiConstant(Code::kHeaderSize));
+  environment()->Push(result);
+  environment()->Push(jsgraph()->TheHoleConstant());  // pending_message_obj
+  environment()->Push(jsgraph()->SmiConstant(0));     // has_pending_message
+  environment()->Push(jsgraph()->TheHoleConstant());  // pending_message_script
 
   // Evaluate the finally-block.
   Visit(stmt->finally_block());
   try_control.EndFinally();
 
+  // TODO(mstarzinger): See FullCodeGenerator::ExitFinallyBlock.
+  environment()->Drop(5);
+
   // Dynamic dispatch after the finally-block.
   Node* token = try_control.GetDispatchTokenNode();
-  commands->ApplyDeferredCommands(token);
+  commands->ApplyDeferredCommands(token, result);
 
   // TODO(mstarzinger): Remove bailout once everything works.
   if (!FLAG_turbo_exceptions) SetStackOverflow();
 }
 
 
 void AstGraphBuilder::VisitDebuggerStatement(DebuggerStatement* stmt) {
   // TODO(turbofan): Do we really need a separate reloc-info for this?
   Node* node = NewNode(javascript()->CallRuntime(Runtime::kDebugBreak, 0));
   PrepareFrameState(node, stmt->DebugBreakId());
@@ skipping 1721 matching lines @@
     }
     if (!environment()->IsMarkedAsUnreachable()) {
       // Update the current control dependency for control-producing nodes.
       if (NodeProperties::IsControl(result)) {
         environment_->UpdateControlDependency(result);
       }
       // Add implicit exception continuation for throwing nodes.
       if (!result->op()->HasProperty(Operator::kNoThrow) && inside_try_scope) {
         Node* on_exception = graph()->NewNode(common()->IfException(), result);
         environment_->UpdateControlDependency(on_exception);
-        execution_control()->ThrowValue(jsgraph()->UndefinedConstant());
+        execution_control()->ThrowValue(result);
       }
       // Add implicit success continuation for throwing nodes.
       if (!result->op()->HasProperty(Operator::kNoThrow)) {
         Node* on_success = graph()->NewNode(common()->IfSuccess(), result);
         environment_->UpdateControlDependency(on_success);
       }
     }
   }
 
   return result;
@@ skipping 197 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8