Remove useless type `GenericFunctor`

`GenericFunctor` is substituted with the `std::integral_constant`
template. This also allows us to remove code that requires C++14.

It also removes the now useless cmake tests on the compiler flag
`-Wno-error=noexcept-type` that was introduced to disable fatal warnings
on the type `GenericFunctor`.
Now that this type has been removed the check is not necessary anymore,
because the `std::integral_constant` template used now does not cause
the warning.
So we can go back to enabling the fatal warnings.

CMakeLists.txt

@@ -77,7 +77,6 @@ endmacro()
 add_flag_if_available("-Wno-error=unused-variable")
 add_flag_if_available("-Wno-error=unused-function")
 add_flag_if_available("-Wno-error=return-type")
-add_flag_if_available("-Wno-error=noexcept-type")
 add_flag_if_available("-Wno-error=unused-but-set-variable")
 add_flag_if_available("-Wno-error=maybe-uninitialized")
 add_flag_if_available("-Wno-error=ignored-attributes")

main.cpp

@@ -14,6 +14,7 @@
 #include <iostream>
 #include <sstream>
 #include <string>
+#include <type_traits>
 #include <vector>
 
 extern "C" {
@@ -55,7 +56,15 @@ struct ProgramParameters {
   bool External;
 };
 
-using LibraryDestructor = GenericFunctor<decltype(&dlclose), &dlclose>;
+// When LibraryPointer is destroyed, the destructor calls
+// LibraryDestructor::operator()(LibraryPointer::get()).
+// The problem is that LibraryDestructor::operator() does not take arguments,
+// while the destructor tries to pass a void * argument, so it does not match.
+// However, LibraryDestructor is an alias for
+// std::intgral_constant<decltype(&dlclose), &dlclose >, which has an implicit
+// conversion operator to value_type, which unwraps the &dlclose from the
+// std::integral_constant, making it callable.
+using LibraryDestructor = std::integral_constant<decltype(&dlclose), &dlclose>;
 using LibraryPointer = std::unique_ptr<void, LibraryDestructor>;
 
 static const char *const Usage[] = {

ptcinterface.h

@@ -7,6 +7,7 @@
 
 // Standard includes
 #include <memory>
+#include <type_traits>
 
 // Local includes
 #include "revamb.h"
@@ -14,8 +15,8 @@
 #include "ptc.h"
 
 using PTCInstructionListDestructor =
-  GenericFunctor<decltype(&ptc_instruction_list_free),
-                 &ptc_instruction_list_free>;
+  std::integral_constant<decltype(&ptc_instruction_list_free),
+                         &ptc_instruction_list_free>;
 using PTCInstructionListPtr = std::unique_ptr<PTCInstructionList,
                                               PTCInstructionListDestructor>;
 

revamb.h

@@ -115,15 +115,6 @@ private:
   llvm::StringRef StackPointerRegister;
 };
 
-// TODO: this requires C++14
-template<typename FnTy, FnTy Ptr>
-struct GenericFunctor {
-  template<typename... Args>
-  auto operator()(Args... args) -> decltype(Ptr(args...)) {
-    return Ptr(args...);
-  }
-};
-
 // TODO: move me somewhere more appropriate
 static inline bool startsWith(std::string String, std::string Prefix) {
   return String.substr(0, Prefix.size()) == Prefix;