[stubs] Port StringAddStub to TF

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index e262d1592aa1efc3bf3454c28a5b13029f64e8b1..52bd498a7bff4c60817e78123118be3ee34e7f50 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -345,6 +345,35 @@ void StringAddStub::PrintBaseName(std::ostream& os) const {  // NOLINT
   os << "StringAddStub_" << flags() << "_" << pretenure_flag();
 }
 
+void StringAddStub::GenerateAssembly(CodeStubAssembler* assembler) const {
+  typedef compiler::Node Node;
+  Node* left = assembler->Parameter(Descriptor::kLeft);
+  Node* right = assembler->Parameter(Descriptor::kRight);
+  Node* context = assembler->Parameter(Descriptor::kContext);
+
+  if ((flags() & STRING_ADD_CHECK_LEFT) != 0) {
+    DCHECK((flags() & STRING_ADD_CONVERT) != 0);
+    left = assembler->ToString(context,
+                               assembler->JSReceiverToPrimitive(context, left));

[Igor Sheludko, 2016/10/13 15:41:33]

Note: we could generate a better code here if we combine these two calls (no
duplicate smi checks, no duplicate instance type loads in certain cases).

[danno, 2016/10/17 14:23:26]

Yes, but it somewhat breaks the abstraction of having nicely encapulated chunks
of functionality. How about I add a TODO and we can consider this if there is a
big performance regression or it becomes an issue at some point.

+  }
+  if ((flags() & STRING_ADD_CHECK_RIGHT) != 0) {
+    DCHECK((flags() & STRING_ADD_CONVERT) != 0);
+    right = assembler->ToString(
+        context, assembler->JSReceiverToPrimitive(context, right));
+  }
+
+  if ((flags() & STRING_ADD_CHECK_BOTH) == 0) {
+    CodeStubAssembler::AllocationFlag flags =
+        (pretenure_flag() == TENURED) ? CodeStubAssembler::kPretenured
+                                      : CodeStubAssembler::kNone;
+    assembler->Return(assembler->StringAdd(context, left, right, flags));
+  } else {
+    StringAddStub stub(isolate(), STRING_ADD_CHECK_NONE, pretenure_flag());
+    StringAddDescriptor descriptor(isolate());
+    assembler->TailCallStub(descriptor, assembler->HeapConstant(stub.GetCode()),

[Igor Sheludko, 2016/10/13 15:41:33]

I think
  Callable callable = CodeFactory::StringAdd().
  assembler->TailCallStub(callable, ...)
is better because the correct call interface descriptor will be used
automatically.

[danno, 2016/10/17 14:23:26]

Done.

+                            context, left, right);
+  }
+}
 
 InlineCacheState CompareICStub::GetICState() const {
   CompareICState::State state = Max(left(), right());
@@ -2163,13 +2192,6 @@ void BinaryOpWithAllocationSiteStub::InitializeDescriptor(
       FUNCTION_ADDR(Runtime_BinaryOpIC_MissWithAllocationSite));
 }
 
-
-void StringAddStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
-  descriptor->Initialize(Runtime::FunctionForId(Runtime::kStringAdd)->entry);
-  descriptor->SetMissHandler(Runtime::kStringAdd);
-}
-
-
 void GetPropertyStub::GenerateAssembly(CodeStubAssembler* assembler) const {
   typedef compiler::Node Node;
   typedef CodeStubAssembler::Label Label;