From b062266b8eb01df5aebd5783c58d2b1b2994ec98 Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Sun, 11 Feb 2018 10:47:00 +0000
Subject: [PATCH] emit_x64_vector: More explicit lambda decay

---
 src/backend_x64/emit_x64_vector.cpp |  3 ++-
 src/common/mp.h                     | 14 +++++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/backend_x64/emit_x64_vector.cpp b/src/backend_x64/emit_x64_vector.cpp
index 7f5377ef..7e4fcd93 100644
--- a/src/backend_x64/emit_x64_vector.cpp
+++ b/src/backend_x64/emit_x64_vector.cpp
@@ -9,6 +9,7 @@
 #include "backend_x64/emit_x64.h"
 #include "common/assert.h"
 #include "common/common_types.h"
+#include "common/mp.h"
 #include "frontend/ir/basic_block.h"
 #include "frontend/ir/microinstruction.h"
 #include "frontend/ir/opcodes.h"
@@ -31,7 +32,7 @@ static void EmitVectorOperation(BlockOfCode& code, EmitContext& ctx, IR::Inst* i
 
 template <typename Lambda>
 static void EmitTwoArgumentFallback(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst, Lambda lambda) {
-    const auto fn = +lambda; // Force decay of lambda to function pointer
+    const auto fn = static_cast<mp::equivalent_function_type_t<Lambda>*>(lambda);
     constexpr u32 stack_space = 3 * 16;
     auto args = ctx.reg_alloc.GetArgumentInfo(inst);
     const Xbyak::Xmm arg1 = ctx.reg_alloc.UseXmm(args[0]);
diff --git a/src/common/mp.h b/src/common/mp.h
index f96d8947..ec934b82 100644
--- a/src/common/mp.h
+++ b/src/common/mp.h
@@ -13,7 +13,9 @@ namespace Dynarmic::mp {
 
 /// Used to provide information about an arbitrary function.
 template <typename Function>
-struct FunctionInfo;
+struct FunctionInfo : public FunctionInfo<decltype(&Function::operator())>
+{
+};
 
 /**
  * Partial specialization for function types.
@@ -32,6 +34,8 @@ struct FunctionInfo<R(Args...)>
         static_assert(args_count != 0 && ParameterIndex < args_count, "Non-existent function parameter index");
         using type = std::tuple_element_t<ParameterIndex, std::tuple<Args...>>;
     };
+
+    using equivalent_function_type = R(Args...);
 };
 
 /// Partial specialization for function pointers
@@ -79,4 +83,12 @@ using return_type_t = typename FunctionInfo<Function>::return_type;
 template <typename Function>
 using class_type_t = typename FunctionInfo<Function>::class_type;
 
+/**
+ * Helper template for retrieving the equivalent function type of a member function or functor.
+ *
+ * @tparam Function The function type to get the return type of.
+ */
+template <typename Function>
+using equivalent_function_type_t = typename FunctionInfo<Function>::equivalent_function_type;
+
 } // namespace Dynarmic::mp