Improve template instantiation for GetMethodTemplate

Author: aaronj0

lib/Interpreter/CppInterOp.cpp

@@ -1004,8 +1004,9 @@ namespace Cpp {
         continue;
 #endif
 
-      // FIXME : first score based on the type similarity before forcing
+      // TODO(aaronj0) : first score based on the type similarity before forcing
       // instantiation.
+
       TCppFunction_t instantiated =
           InstantiateTemplate(candidate, arg_types.data(), arg_types.size());
       if (instantiated)
@@ -1018,6 +1019,19 @@ namespace Cpp {
                                           explicit_types.size());
       if (instantiated)
         return instantiated;
+
+      // join explicit and arg_types
+      std::vector<TemplateArgInfo> total_arg_set;
+      total_arg_set.reserve(explicit_types.size() + arg_types.size());
+      total_arg_set.insert(total_arg_set.end(), explicit_types.begin(),
+                           explicit_types.end());
+      total_arg_set.insert(total_arg_set.end(), arg_types.begin(),
+                           arg_types.end());
+
+      instantiated = InstantiateTemplate(candidate, total_arg_set.data(),
+                                         total_arg_set.size());
+      if (instantiated)
+        return instantiated;
     }
     return nullptr;
   }

unittests/CppInterOp/FunctionReflectionTest.cpp

@@ -597,6 +597,7 @@ TEST(FunctionReflectionTest, BestTemplateFunctionMatch) {
           template<class A> long get_size(A&);
           template<class A> long get_size();
           template<class A, class B> long get_size(A a, B b);
+          template<class A> long add_size(float a);
       };
 
       template<class A>
@@ -609,6 +610,11 @@ TEST(FunctionReflectionTest, BestTemplateFunctionMatch) {
           return sizeof(A) + 1;
       }
 
+      template<class A>
+      long MyTemplatedMethodClass::add_size(float a) {
+          return sizeof(A) + long(a);
+      }
+
       template<class A, class B>
       long MyTemplatedMethodClass::get_size(A a, B b) {
           return sizeof(A) + sizeof(B);
@@ -626,21 +632,24 @@ TEST(FunctionReflectionTest, BestTemplateFunctionMatch) {
   std::vector<Cpp::TemplateArgInfo> args0;
   std::vector<Cpp::TemplateArgInfo> args1 = {C.IntTy.getAsOpaquePtr()};
   std::vector<Cpp::TemplateArgInfo> args2 = {C.CharTy.getAsOpaquePtr(), C.FloatTy.getAsOpaquePtr()};
+  std::vector<Cpp::TemplateArgInfo> args3 = {C.FloatTy.getAsOpaquePtr()};
 
   std::vector<Cpp::TemplateArgInfo> explicit_args0;
   std::vector<Cpp::TemplateArgInfo> explicit_args1 = {C.IntTy.getAsOpaquePtr()};
-  
 
   Cpp::TCppFunction_t func1 = Cpp::BestTemplateFunctionMatch(candidates, explicit_args0, args1);
   Cpp::TCppFunction_t func2 = Cpp::BestTemplateFunctionMatch(candidates, explicit_args1, args0);
   Cpp::TCppFunction_t func3 = Cpp::BestTemplateFunctionMatch(candidates, explicit_args0, args2);
+  Cpp::TCppFunction_t func4 = Cpp::BestTemplateFunctionMatch(candidates, explicit_args1, args3);
 
   EXPECT_EQ(Cpp::GetFunctionSignature(func1),
             "template<> long MyTemplatedMethodClass::get_size<int>(int &)");
   EXPECT_EQ(Cpp::GetFunctionSignature(func2),
             "template<> long MyTemplatedMethodClass::get_size<int>()");
   EXPECT_EQ(Cpp::GetFunctionSignature(func3),
             "template<> long MyTemplatedMethodClass::get_size<char, float>(char a, float b)");
+  EXPECT_EQ(Cpp::GetFunctionSignature(func4),
+            "template<> long MyTemplatedMethodClass::get_size<float>(float &)");
 }
 
 TEST(FunctionReflectionTest, IsPublicMethod) {