[turbofan] Properly call %TraceExit on explicit return.

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/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 594 matching lines @@
   if (stack_check) {
     Node* node = NewNode(javascript()->StackCheck());
     PrepareFrameState(node, BailoutId::FunctionEntry());
   }
 
   // Visit statements in the function body.
   VisitStatements(info()->literal()->body());
 
   // Emit tracing call if requested to do so.
   if (FLAG_trace) {
     // TODO(mstarzinger): Only traces implicit return.

[Michael Starzinger, 2016/02/01 18:33:16]

Once the below comments about AstGraphBuilder::BuildReturn is addressed, this
explicit tracing code can be remove. It is covered by the call to BuildReturn
then.

[Benedikt Meurer, 2016/02/02 05:01:41]

Done.

     Node* return_value = jsgraph()->UndefinedConstant();
     NewNode(javascript()->CallRuntime(Runtime::kTraceExit), return_value);
   }
 
   // Return 'undefined' in case we can fall off the end.
   BuildReturn(jsgraph()->UndefinedConstant());
 }
 
 
 void AstGraphBuilder::ClearNonLiveSlotsInFrameStates() {
@@ skipping 570 matching lines @@
 
 
 void AstGraphBuilder::VisitBreakStatement(BreakStatement* stmt) {
   execution_control()->BreakTo(stmt->target());
 }
 
 
 void AstGraphBuilder::VisitReturnStatement(ReturnStatement* stmt) {
   VisitForValue(stmt->expression());
   Node* result = environment()->Pop();
+  if (FLAG_trace) {
+    NewNode(javascript()->CallRuntime(Runtime::kTraceExit), result);

[Michael Starzinger, 2016/02/01 18:33:16]

This needs to go into AstGraphBuilder::BuildReturn, otherwise it is being
executed before the finally block.

[Benedikt Meurer, 2016/02/02 05:01:41]

Done.

+  }
   execution_control()->ReturnValue(result);
 }
 
 
 void AstGraphBuilder::VisitWithStatement(WithStatement* stmt) {
   VisitForValue(stmt->expression());
   Node* value = environment()->Pop();
   Node* object = BuildToObject(value, stmt->ToObjectId());
   const Operator* op = javascript()->CreateWithContext();
   Node* context = NewNode(op, object, GetFunctionClosureForContext());
@@ skipping 3124 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