Minor change to `byval` for readonly parameters

4 files changed, 56 insertions, 5 deletions

diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index b22d7c9a2..34c1ec9b4 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -495,11 +495,11 @@ gb_internal lbValue lb_map_get_proc_for_type(lbModule *m, Type *type) {
 
 	lb_add_proc_attribute_at_index(p, 1+0, "nonnull");
 	lb_add_proc_attribute_at_index(p, 1+0, "noalias");
-	// lb_add_proc_attribute_at_index(p, 1+0, "readonly");
+	lb_add_proc_attribute_at_index(p, 1+0, "readonly");
 
 	lb_add_proc_attribute_at_index(p, 1+2, "nonnull");
 	lb_add_proc_attribute_at_index(p, 1+2, "noalias");
-	// lb_add_proc_attribute_at_index(p, 1+2, "readonly");
+	lb_add_proc_attribute_at_index(p, 1+2, "readonly");
 
 	lbBlock *loop_block = lb_create_block(p, "loop");
 	lbBlock *hash_block = lb_create_block(p, "hash");
@@ -599,6 +599,8 @@ gb_internal lbValue lb_map_get_proc_for_type(lbModule *m, Type *type) {
 		LLVMBuildRet(p->builder, res.value);
 	}
 
+	gb_printf_err("%s\n", LLVMPrintValueToString(p->value));
+
 
 	return {p->value, p->type};
 }
diff --git a/src/llvm_backend.hpp b/src/llvm_backend.hpp
index e151d2be1..7bf287b49 100644
--- a/src/llvm_backend.hpp
+++ b/src/llvm_backend.hpp
@@ -325,6 +325,7 @@ struct lbProcedure {
 	lbTargetList *   target_list;
 	PtrMap<Entity *, lbValue> direct_parameters;
 	bool             in_multi_assignment;
+	Array<LLVMValueRef> raw_input_parameters;
 
 	Ast *curr_stmt;
 
diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 89a59de62..c1cbff048 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -538,6 +538,10 @@ gb_internal void lb_begin_procedure_body(lbProcedure *p) {
 		if (p->type->Proc.params != nullptr) {
 			TypeTuple *params = &p->type->Proc.params->Tuple;
 
+			unsigned raw_input_parameters_count = LLVMCountParams(p->value);
+			p->raw_input_parameters = array_make<LLVMValueRef>(permanent_allocator(), raw_input_parameters_count);
+			LLVMGetParams(p->value, p->raw_input_parameters.data);
+
 			unsigned param_index = 0;
 			for_array(i, params->variables) {
 				Entity *e = params->variables[i];
@@ -1028,9 +1032,14 @@ gb_internal lbValue lb_emit_call(lbProcedure *p, lbValue value, Array<lbValue> c
 			} else if (arg->kind == lbArg_Indirect) {
 				lbValue ptr = {};
 				if (arg->is_byval) {
-					if (is_odin_cc && are_types_identical(original_type, t_source_code_location)) {
-						ptr = lb_address_from_load_or_generate_local(p, x);
-					} else {
+					if (is_odin_cc) {
+						if (are_types_identical(original_type, t_source_code_location)) {
+							ptr = lb_address_from_load_or_generate_local(p, x);
+						} else {
+							ptr = lb_address_from_load_if_readonly_parameter(p, x);
+						}
+					}
+					if (ptr.value == nullptr) {
 						ptr = lb_copy_value_to_ptr(p, x, original_type, arg->byval_alignment);
 					}
 				} else if (is_odin_cc) {
diff --git a/src/llvm_backend_utility.cpp b/src/llvm_backend_utility.cpp
index dbed32b82..a4ef61531 100644
--- a/src/llvm_backend_utility.cpp
+++ b/src/llvm_backend_utility.cpp
@@ -868,6 +868,45 @@ gb_internal lbValue lb_address_from_load(lbProcedure *p, lbValue value) {
 	return {};
 }
 
+gb_internal lbValue lb_address_from_load_if_readonly_parameter(lbProcedure *p, lbValue x) {
+	if (!LLVMIsALoadInst(x.value)) {
+		return {};
+	}
+
+	LLVMValueRef optr = LLVMGetOperand(x.value, 0);
+	while (optr && LLVMIsABitCastInst(optr)) {
+		optr = LLVMGetOperand(optr, 0);
+	}
+	LLVMAttributeIndex param_index = 1;
+	if (p->return_ptr.addr.value) {
+		param_index++;
+	}
+
+	bool is_parameter = false;
+	for (LLVMValueRef param : p->raw_input_parameters) {
+		if (param == optr) {
+			is_parameter = true;
+			break;
+		}
+		param_index++;
+	}
+	if (is_parameter) {
+		unsigned readonly_attr_kind = LLVMGetEnumAttributeKindForName("readonly", 8);
+		unsigned n = LLVMGetAttributeCountAtIndex(p->value, param_index);
+		if (n) {
+			TEMPORARY_ALLOCATOR_GUARD();
+			LLVMAttributeRef *attrs = gb_alloc_array(temporary_allocator(), LLVMAttributeRef, n);
+			LLVMGetAttributesAtIndex(p->value, param_index, attrs);
+			for (unsigned i = 0; i < n; i++) {
+				if (LLVMGetEnumAttributeKind(attrs[i]) == readonly_attr_kind) {
+					return lb_address_from_load_or_generate_local(p, x);
+				}
+			}
+		}
+	}
+	return {};
+}
+
 
 gb_internal lbStructFieldRemapping lb_get_struct_remapping(lbModule *m, Type *t) {
 	t = base_type(t);