CodeStubAssembler can generate code for builtins

test/cctest/compiler/test-code-stub-assembler.cc

Index: test/cctest/compiler/test-code-stub-assembler.cc
diff --git a/test/cctest/compiler/test-code-stub-assembler.cc b/test/cctest/compiler/test-code-stub-assembler.cc
index 0306561020abe41e5342f9cc209062f67bd9d208..64c8a99dddbb0b40cb86c2eb615f2858e0eea021 100644
--- a/test/cctest/compiler/test-code-stub-assembler.cc
+++ b/test/cctest/compiler/test-code-stub-assembler.cc
@@ -13,12 +13,19 @@ namespace compiler {
 
 class CodeStubAssemblerTester : public CodeStubAssembler {
  public:
+  // Test generating code for a stub.
   CodeStubAssemblerTester(Isolate* isolate,
                           const CallInterfaceDescriptor& descriptor)
       : CodeStubAssembler(isolate, isolate->runtime_zone(), descriptor,
                           Code::ComputeFlags(Code::STUB), "test"),
         scope_(isolate) {}
 
+  // Test generating code for a JS function (e.g. builtins).
+  CodeStubAssemblerTester(Isolate* isolate, int parameter_count)
+      : CodeStubAssembler(isolate, isolate->runtime_zone(), parameter_count,
+                          Code::ComputeFlags(Code::FUNCTION), "test"),
+        scope_(isolate) {}
+
  private:
   HandleScope scope_;
   LocalContext context_;
@@ -247,6 +254,20 @@ TEST(FixedArrayAccessSmiIndex) {
   CHECK_EQ(733, Handle<Smi>::cast(result.ToHandleChecked())->value());
 }
 
+TEST(JSFunction) {
+  const int kNumParams = 3;  // Receiver, left, right.
+  Isolate* isolate(CcTest::InitIsolateOnce());
+  CodeStubAssemblerTester m(isolate, kNumParams);
+  m.Return(m.SmiTag(
+      m.Int32Add(m.SmiUntag(m.Parameter(1)), m.SmiUntag(m.Parameter(2)))));
+  Handle<Code> code = m.GenerateCode();
+  FunctionTester ft(kNumParams - 1, code);  // Implicit undefined receiver.

[Jarin, 2016/02/18 09:04:38]

Apparently, there is a bug in FunctionTester::BuildFunction - it adds an extra
argument to the function. Sorry about that.

Fix here: https://codereview.chromium.org/1711513003/ (will try to land ASAP).

[binji, 2016/02/18 19:35:16]

Acknowledged.

+  Handle<Object> left = Handle<Smi>(Smi::FromInt(23), isolate);
+  Handle<Object> right = Handle<Smi>(Smi::FromInt(34), isolate);
+  MaybeHandle<Object> result = ft.Call(left, right);
+  CHECK_EQ(57, Handle<Smi>::cast(result.ToHandleChecked())->value());
+}

[Jarin, 2016/02/18 12:32:15]

Actually, FunctionTester as a whole seems to be a terrible hack (this was
pointed out to me by Benedikt, I agree). How about this:

namespace {

Handle<JSFunction> CreateFunctionFromCode(int parameter_count_with_receiver,
                                          Handle<Code> code) {
  Isolate* isolate = code->GetIsolate();
  Handle<String> name = isolate->factory()->InternalizeUtf8String("test");
  Handle<JSFunction> function =
      isolate->factory()->NewFunctionWithoutPrototype(name, code);
  function->shared()->set_internal_formal_parameter_count(
      parameter_count_with_receiver - 1);  // Implicit undefined receiver.
  return function;
}

}  // namespace

TEST(JSFunction) {
  const int kNumParams = 3;  // Receiver, left, right.
  Isolate* isolate(CcTest::InitIsolateOnce());
  CodeStubAssemblerTester m(isolate, kNumParams);
  m.Return(m.SmiTag(
      m.Int32Add(m.SmiUntag(m.Parameter(1)), m.SmiUntag(m.Parameter(2)))));
  Handle<Code> code = m.GenerateCode();
  Handle<JSFunction> function = CreateFunctionFromCode(kNumParams, code);

  // Run the function.
  Handle<Object> args[] = {Handle<Smi>(Smi::FromInt(23), isolate),
                           Handle<Smi>(Smi::FromInt(34), isolate)};
  MaybeHandle<Object> result =
      Execution::Call(isolate, function, isolate->factory()->undefined_value(),
                      arraysize(args), args);
  CHECK_EQ(57, Handle<Smi>::cast(result.ToHandleChecked())->value());
}

[binji, 2016/02/18 19:35:17]

Done.

+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8