[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 592 matching lines @@
 
   // Build a stack-check before the body.
   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.
-    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() {
   if (!FLAG_analyze_environment_liveness ||
       !info()->is_deoptimization_enabled()) {
     return;
   }
@@ skipping 3160 matching lines @@
       javascript()->CallRuntime(Runtime::kThrowUnsupportedSuperError);
   Node* call = NewNode(op);
   PrepareFrameState(call, bailout_id);
   Node* control = NewNode(common()->Throw(), call);
   UpdateControlDependencyToLeaveFunction(control);
   return call;
 }
 
 
 Node* AstGraphBuilder::BuildReturn(Node* return_value) {
+  // Emit tracing call if requested to do so.
+  if (FLAG_trace) {
+    return_value =
+        NewNode(javascript()->CallRuntime(Runtime::kTraceExit), return_value);
+  }
   Node* control = NewNode(common()->Return(), return_value);
   UpdateControlDependencyToLeaveFunction(control);
   return control;
 }
 
 
 Node* AstGraphBuilder::BuildThrow(Node* exception_value) {
   NewNode(javascript()->CallRuntime(Runtime::kReThrow), exception_value);
   Node* control = NewNode(common()->Throw(), exception_value);
   UpdateControlDependencyToLeaveFunction(control);
@@ skipping 530 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