Tweak the TurboFan pipeline for stub compilation.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index b622d9ce8574932f79225fcef40f9ec7b6997da4..d31cbeac851d3ef01ebe008e3e0c03e60c8a2ea3 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -221,33 +221,21 @@ void CompilationInfo::RollbackDependencies() {
 
 
 int CompilationInfo::num_parameters() const {
-  if (IsStub()) {
-    DCHECK(parameter_count_ > 0);
-    return parameter_count_;
-  } else {
-    return scope()->num_parameters();
-  }
+  return has_scope() ? scope()->num_parameters() : parameter_count_;
 }
 
 
 int CompilationInfo::num_heap_slots() const {
-  if (IsStub()) {
-    return 0;
-  } else {
-    return scope()->num_heap_slots();
-  }
+  return has_scope() ? scope()->num_heap_slots() : 0;
 }
 
 
 Code::Flags CompilationInfo::flags() const {
-  if (IsStub()) {
-    return Code::ComputeFlags(code_stub()->GetCodeKind(),
-                              code_stub()->GetICState(),
-                              code_stub()->GetExtraICState(),
-                              code_stub()->GetStubType());
-  } else {
-    return Code::ComputeFlags(Code::OPTIMIZED_FUNCTION);
-  }
+  return code_stub() != nullptr
+             ? Code::ComputeFlags(
+                   code_stub()->GetCodeKind(), code_stub()->GetICState(),
+                   code_stub()->GetExtraICState(), code_stub()->GetStubType())
+             : Code::ComputeFlags(Code::OPTIMIZED_FUNCTION);
 }