Improvement to the Odin calling conventions to pass certain things by "implicit reference" (`const &` in C++)

3 files changed, 11 insertions, 3 deletions

diff --git a/src/check_type.cpp b/src/check_type.cpp
index f4e5b49d0..5b20a48fc 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -2084,6 +2084,14 @@ void set_procedure_abi_types(CheckerContext *c, Type *type) {
 			Type *original_type = e->type;
 			Type *new_type = type_to_abi_compat_param_type(c->allocator, original_type, type->Proc.calling_convention);
 			type->Proc.abi_compat_params[i] = new_type;
+			switch (type->Proc.calling_convention) {
+			case ProcCC_Odin:
+			case ProcCC_Contextless:
+				if (is_type_pointer(new_type) & !is_type_pointer(e->type)) {
+					e->flags |= EntityFlag_ImplicitReference;
+				}
+				break;
+			}
 		}
 	}
 
diff --git a/src/entity.cpp b/src/entity.cpp
index 3318eac24..0c05a9bf6 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -48,7 +48,8 @@ enum EntityFlag {
 	EntityFlag_NotExported   = 1<<14,
 
 	EntityFlag_Static        = 1<<16,
-	// EntityFlag_Reference     = 1<<17,
+
+	EntityFlag_ImplicitReference = 1<<17, // NOTE(bill): equivalent to `const &` in C++
 
 	EntityFlag_CVarArg       = 1<<20,
 	EntityFlag_AutoCast      = 1<<21,
diff --git a/src/ir.cpp b/src/ir.cpp
index 82f9fa755..8c5dcb963 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -3004,9 +3004,8 @@ irValue *ir_emit_call(irProcedure *p, irValue *value, Array<irValue *> args, Pro
 		if (are_types_identical(arg_type, new_type)) {
 			// NOTE(bill): Done
 		} else if (!are_types_identical(original_type, new_type)) {
-
 			if (is_type_pointer(new_type) && !is_type_pointer(original_type)) {
-				if (e->flags&EntityFlag_Value) {
+				if (e->flags&EntityFlag_ImplicitReference) {
 					args[i] = ir_address_from_load_or_generate_local(p, args[i]);
 				} else if (!is_type_pointer(arg_type)) {
 					args[i] = ir_copy_value_to_ptr(p, args[i], original_type, 16);