C#: Optimize struct marshalling

- We no longer box struct to return them from internal calls.
- Use reinterpret_cast if the managed struct layout is the same as the native struct.

2 files changed, 58 insertions, 45 deletions

diff --git a/modules/mono/editor/bindings_generator.cpp b/modules/mono/editor/bindings_generator.cpp
index f4c3033d19..41666bc3e9 100644
--- a/modules/mono/editor/bindings_generator.cpp
+++ b/modules/mono/editor/bindings_generator.cpp
@@ -97,7 +97,7 @@
 #define C_METHOD_MONOARRAY_TO(m_type) C_NS_MONOMARSHAL "::mono_array_to_" #m_type
 #define C_METHOD_MONOARRAY_FROM(m_type) C_NS_MONOMARSHAL "::" #m_type "_to_mono_array"
 
-#define BINDINGS_GENERATOR_VERSION UINT32_C(3)
+#define BINDINGS_GENERATOR_VERSION UINT32_C(4)
 
 const char *BindingsGenerator::TypeInterface::DEFAULT_VARARG_C_IN = "\t%0 %1_in = %1;\n";
 
@@ -1993,18 +1993,18 @@ void BindingsGenerator::_populate_builtin_type_interfaces() {
 
 	TypeInterface itype;
 
-#define INSERT_STRUCT_TYPE(m_type, m_type_in)                                                         \
-	{                                                                                                 \
-		itype = TypeInterface::create_value_type(String(#m_type));                                    \
-		itype.c_in = "\tMARSHALLED_IN(" #m_type ", %1, %1_in);\n";                                    \
-		itype.c_out = "\tMARSHALLED_OUT(" #m_type ", %1, ret_out)\n"                                  \
-					  "\treturn mono_value_box(mono_domain_get(), CACHED_CLASS_RAW(%2), ret_out);\n"; \
-		itype.c_arg_in = "&%s_in";                                                                    \
-		itype.c_type_in = m_type_in;                                                                  \
-		itype.cs_in = "ref %s";                                                                       \
-		itype.cs_out = "return (%1)%0;";                                                              \
-		itype.im_type_out = "object";                                                                 \
-		builtin_types.insert(itype.cname, itype);                                                     \
+#define INSERT_STRUCT_TYPE(m_type, m_type_in)                          \
+	{                                                                  \
+		itype = TypeInterface::create_value_type(String(#m_type));     \
+		itype.c_in = "\t%0 %1_in = MARSHALLED_IN(" #m_type ", %1);\n"; \
+		itype.c_out = "\treturn MARSHALLED_OUT(" #m_type ", %1);\n";   \
+		itype.c_arg_in = "&%s_in";                                     \
+		itype.c_type_in = "GDMonoMarshal::M_" #m_type "*";             \
+		itype.c_type_out = "GDMonoMarshal::M_" #m_type;                \
+		itype.cs_in = "ref %s";                                        \
+		itype.cs_out = "return (%1)%0;";                               \
+		itype.im_type_out = itype.cs_type;                             \
+		builtin_types.insert(itype.cname, itype);                      \
 	}
 
 	INSERT_STRUCT_TYPE(Vector2, "real_t*")
@@ -2022,26 +2022,31 @@ void BindingsGenerator::_populate_builtin_type_interfaces() {
 
 	// bool
 	itype = TypeInterface::create_value_type(String("bool"));
-	itype.c_arg_in = "&%s_in";
-	// /* MonoBoolean <---> bool
-	itype.c_in = "\t%0 %1_in = (%0)%1;\n";
-	itype.c_out = "\treturn (%0)%1;\n";
-	itype.c_type = "bool";
-	// */
-	itype.c_type_in = "MonoBoolean";
-	itype.c_type_out = itype.c_type_in;
+
+	{
+		// MonoBoolean <---> bool
+		itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+		itype.c_out = "\treturn (%0)%1;\n";
+		itype.c_type = "bool";
+		itype.c_type_in = "MonoBoolean";
+		itype.c_type_out = itype.c_type_in;
+		itype.c_arg_in = "&%s_in";
+	}
 	itype.im_type_in = itype.name;
 	itype.im_type_out = itype.name;
 	builtin_types.insert(itype.cname, itype);
 
 	// int
+	// C interface is the same as that of enums. Remember to apply any
+	// changes done here to TypeInterface::postsetup_enum_type as well
 	itype = TypeInterface::create_value_type(String("int"));
 	itype.c_arg_in = "&%s_in";
-	// /* ptrcall only supports int64_t and uint64_t
-	itype.c_in = "\t%0 %1_in = (%0)%1;\n";
-	itype.c_out = "\treturn (%0)%1;\n";
-	itype.c_type = "int64_t";
-	// */
+	{
+		// The expected types for parameters and return value in ptrcall are 'int64_t' or 'uint64_t'.
+		itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+		itype.c_out = "\treturn (%0)%1;\n";
+		itype.c_type = "int64_t";
+	}
 	itype.c_type_in = "int32_t";
 	itype.c_type_out = itype.c_type_in;
 	itype.im_type_in = itype.name;
@@ -2050,21 +2055,22 @@ void BindingsGenerator::_populate_builtin_type_interfaces() {
 
 	// real_t
 	itype = TypeInterface();
+	itype.name = "float"; // The name is always "float" in Variant, even with REAL_T_IS_DOUBLE.
+	itype.cname = itype.name;
 #ifdef REAL_T_IS_DOUBLE
-	itype.name = "double";
+	itype.proxy_name = "double";
 #else
-	itype.name = "float";
+	itype.proxy_name = "float";
 #endif
-	itype.cname = itype.name;
-	itype.proxy_name = itype.name;
-	itype.c_arg_in = "&%s_in";
-	//* ptrcall only supports double
-	itype.c_in = "\t%0 %1_in = (%0)%1;\n";
-	itype.c_out = "\treturn (%0)%1;\n";
-	itype.c_type = "double";
-	//*/
-	itype.c_type_in = "real_t";
-	itype.c_type_out = "real_t";
+	{
+		// The expected type for parameters and return value in ptrcall is 'double'.
+		itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+		itype.c_out = "\treturn (%0)%1;\n";
+		itype.c_type = "double";
+		itype.c_type_in = "real_t";
+		itype.c_type_out = "real_t";
+		itype.c_arg_in = "&%s_in";
+	}
 	itype.cs_type = itype.proxy_name;
 	itype.im_type_in = itype.proxy_name;
 	itype.im_type_out = itype.proxy_name;
diff --git a/modules/mono/editor/bindings_generator.h b/modules/mono/editor/bindings_generator.h
index ad89255ba5..7ae52e180f 100644
--- a/modules/mono/editor/bindings_generator.h
+++ b/modules/mono/editor/bindings_generator.h
@@ -223,7 +223,7 @@ class BindingsGenerator {
 		String c_in;
 
 		/**
-		 * Determines the name of the variable that will be passed as argument to a ptrcall.
+		 * Determines the expression that will be passed as argument to ptrcall.
 		 * By default the value equals the name of the parameter,
 		 * this varies for types that require special manipulation via [c_in].
 		 * Formatting elements:
@@ -333,8 +333,6 @@ class BindingsGenerator {
 			itype.proxy_name = itype.name;
 
 			itype.c_type = itype.name;
-			itype.c_type_in = "void*";
-			itype.c_type_out = "MonoObject*";
 			itype.cs_type = itype.proxy_name;
 			itype.im_type_in = "ref " + itype.proxy_name;
 			itype.im_type_out = itype.proxy_name;
@@ -385,10 +383,19 @@ class BindingsGenerator {
 		}
 
 		static void postsetup_enum_type(TypeInterface &r_enum_itype) {
-			r_enum_itype.c_arg_in = "&%s";
-			r_enum_itype.c_type = "int";
-			r_enum_itype.c_type_in = "int";
-			r_enum_itype.c_type_out = "int";
+			// C interface is the same as that of 'int'. Remember to apply any
+			// changes done here to the 'int' type interface as well
+
+			r_enum_itype.c_arg_in = "&%s_in";
+			{
+				// The expected types for parameters and return value in ptrcall are 'int64_t' or 'uint64_t'.
+				r_enum_itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+				r_enum_itype.c_out = "\treturn (%0)%1;\n";
+				r_enum_itype.c_type = "int64_t";
+			}
+			r_enum_itype.c_type_in = "int32_t";
+			r_enum_itype.c_type_out = r_enum_itype.c_type_in;
+
 			r_enum_itype.cs_type = r_enum_itype.proxy_name;
 			r_enum_itype.cs_in = "(int)%s";
 			r_enum_itype.cs_out = "return (%1)%0;";