[turbofan] Preserve pending message while inside 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 1234 matching lines @@
   try_control.EndCatch();
 
   // TODO(mstarzinger): Remove bailout once everything works.
   if (!FLAG_turbo_exceptions) SetStackOverflow();
 }
 
 
 void AstGraphBuilder::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   TryFinallyBuilder try_control(this);
 
+  ExternalReference message_object =
+      ExternalReference::address_of_pending_message_obj(isolate());
+  ExternalReference message_present =
+      ExternalReference::address_of_has_pending_message(isolate());
+  ExternalReference message_script =
+      ExternalReference::address_of_pending_message_script(isolate());
+
   // 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(), 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();
+  Node* token = try_control.GetDispatchTokenNode();
 
-  // TODO(mstarzinger): See FullCodeGenerator::EnterFinallyBlock.
-  environment()->Push(jsgraph()->SmiConstant(Code::kHeaderSize));
+  // The result value, dispatch token and message is expected on the operand
+  // stack (this is in sync with FullCodeGenerator::EnterFinallyBlock).
+  environment()->Push(token);  // TODO(mstarzinger): Cook token!
   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
+  environment()->Push(BuildLoadExternal(message_object, kMachAnyTagged));
+  environment()->Push(BuildLoadExternal(message_present, kMachBool));
+  environment()->Push(BuildLoadExternal(message_script, kMachAnyTagged));
 
   // Evaluate the finally-block.
   Visit(stmt->finally_block());
   try_control.EndFinally();
 
-  // TODO(mstarzinger): See FullCodeGenerator::ExitFinallyBlock.
-  environment()->Drop(5);
+  // The result value, dispatch token and message is restored from the operand
+  // stack (this is in sync with FullCodeGenerator::ExitFinallyBlock).
+  BuildStoreExternal(message_script, kMachAnyTagged, environment()->Pop());
+  BuildStoreExternal(message_present, kMachBool, environment()->Pop());
+  BuildStoreExternal(message_object, kMachAnyTagged, environment()->Pop());
+  result = environment()->Pop();
+  token = environment()->Pop();  // TODO(mstarzinger): Uncook token!
 
   // Dynamic dispatch after the finally-block.
-  Node* token = try_control.GetDispatchTokenNode();
   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));
@@ skipping 1488 matching lines @@
 
 
 Node* AstGraphBuilder::BuildLoadGlobalProxy() {
   Node* global = BuildLoadGlobalObject();
   Node* proxy =
       BuildLoadObjectField(global, JSGlobalObject::kGlobalProxyOffset);
   return proxy;
 }
 
 
+Node* AstGraphBuilder::BuildLoadExternal(ExternalReference reference,
+                                         MachineType type) {
+  return NewNode(jsgraph()->machine()->Load(type),
+                 jsgraph()->ExternalConstant(reference),
+                 jsgraph()->ZeroConstant());

[Benedikt Meurer, 2015/03/06 04:50:49]

This is probably wrong for the generic pipeline and only works because Smi 0 and
intptr_t 0 is currently identical. You should use IntPtrConstant(0) instead.

[Michael Starzinger, 2015/03/06 09:47:36]

Done.

+}
+
+
+Node* AstGraphBuilder::BuildStoreExternal(ExternalReference reference,
+                                          MachineType type, Node* value) {
+  StoreRepresentation representation(type, kNoWriteBarrier);
+  return NewNode(jsgraph()->machine()->Store(representation),
+                 jsgraph()->ExternalConstant(reference),
+                 jsgraph()->ZeroConstant(), value);

[Benedikt Meurer, 2015/03/06 04:50:49]

Same here.

[Michael Starzinger, 2015/03/06 09:47:36]

Done.

+}
+
+
 Node* AstGraphBuilder::BuildToBoolean(Node* input) {
   // TODO(titzer): This should be in a JSOperatorReducer.
   switch (input->opcode()) {
     case IrOpcode::kInt32Constant:
       return jsgraph_->BooleanConstant(!Int32Matcher(input).Is(0));
     case IrOpcode::kFloat64Constant:
       return jsgraph_->BooleanConstant(!Float64Matcher(input).Is(0));
     case IrOpcode::kNumberConstant:
       return jsgraph_->BooleanConstant(!NumberMatcher(input).Is(0));
     case IrOpcode::kHeapConstant: {
@@ skipping 115 matching lines @@
     default:
       UNREACHABLE();
       js_op = NULL;
   }
   return NewNode(js_op, left, right);
 }
 
 
 Node* AstGraphBuilder::BuildStackCheck() {
   IfBuilder stack_check(this);
-  Node* limit =
-      NewNode(jsgraph()->machine()->Load(kMachPtr),
-              jsgraph()->ExternalConstant(
-                  ExternalReference::address_of_stack_limit(isolate())),
-              jsgraph()->ZeroConstant());
+  Node* limit = BuildLoadExternal(
+      ExternalReference::address_of_stack_limit(isolate()), kMachPtr);
   Node* stack = NewNode(jsgraph()->machine()->LoadStackPointer());
   Node* tag = NewNode(jsgraph()->machine()->UintLessThan(), limit, stack);
   stack_check.If(tag, BranchHint::kTrue);
   stack_check.Then();
   stack_check.Else();
   Node* guard = NewNode(javascript()->CallRuntime(Runtime::kStackGuard, 0));
   stack_check.End();
   return guard;
 }
 
@@ skipping 300 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