codegen unions

codegen.c

@@ -534,6 +534,16 @@ void codegen_generate_global_variable_for_struct(struct node *node) {
            asm_keyword_for_size(variable_size(node), tmp_buf));
 }
 
+void codegen_generate_global_variable_for_union(struct node *node) {
+  if (node->var.val != NULL) {
+    compiler_error(current_process, "Unions with values not supported");
+  }
+
+  char tmp_buf[256];
+  asm_push("%s: %s 0", node->var.name,
+           asm_keyword_for_size(variable_size(node), tmp_buf));
+}
+
 void codegen_generate_global_variable(struct node *node) {
   asm_push("; %s %s", node->var.type.type_str, node->var.name);
   switch (node->var.type.type) {
@@ -549,6 +559,10 @@ void codegen_generate_global_variable(struct node *node) {
     codegen_generate_global_variable_for_struct(node);
     break;
 
+  case DATA_TYPE_UNION:
+    codegen_generate_global_variable_for_union(node);
+    break;
+
   case DATA_TYPE_DOUBLE:
   case DATA_TYPE_FLOAT:
     compiler_error(current_process, "Unsupported data type");
@@ -562,6 +576,12 @@ void codegen_generate_struct(struct node *node) {
   }
 }
 
+void codegen_generate_union(struct node *node) {
+  if (node->flags & NODE_FLAG_HAS_VARIABLE_COMBINED) {
+    codegen_generate_global_variable(node->_union.var);
+  }
+}
+
 void codegen_generate_data_section_part(struct node *node) {
   switch (node->type) {
   case NODE_TYPE_VARIABLE:
@@ -572,6 +592,10 @@ void codegen_generate_data_section_part(struct node *node) {
     codegen_generate_struct(node);
     break;
 
+  case NODE_TYPE_UNION:
+    codegen_generate_union(node);
+    break;
+
   default:
     break;
   }

test.c

@@ -1,4 +1,11 @@
+union abc {
+  int x;
+  int y;
+};
+
+union abc a;
+
 int main() {
-  int *x;
-  *x = 50;
+  a.x = 20;
+  return a.y;
 }