Add core language features

- sizeof expression support for variables and expressions
- Union type support with proper memory layout
- Compound literal support for basic types and arrays
- Type casting support with explicit (type) syntax
- Enhanced type system with union handling
- Code formatted with clang-format-18

Author: jserv

src/defs.h

@@ -157,6 +157,7 @@ typedef enum {
     T_typedef,
     T_enum,
     T_struct,
+    T_union,
     T_sizeof,
     T_elipsis, /* ... */
     T_switch,
@@ -184,6 +185,7 @@ typedef enum {
     TYPE_int,
     TYPE_char,
     TYPE_struct,
+    TYPE_union,
     TYPE_typedef
 } base_type_t;
 
@@ -254,6 +256,7 @@ typedef enum {
     /* data type conversion */
     OP_trunc,
     OP_sign_ext,
+    OP_cast,
 
     /* entry point of the state machine */
     OP_start
@@ -531,7 +534,6 @@ typedef struct {
     int polluted;
 } regfile_t;
 
-/* FIXME: replace char[2] with a short data type in ELF header structures */
 /* ELF header */
 typedef struct {
     char e_ident[16];

src/globals.c

@@ -580,7 +580,8 @@ int hard_mul_div = 0;
 type_t *find_type(char *type_name, int flag)
 {
     for (int i = 0; i < types_idx; i++) {
-        if (TYPES[i].base_type == TYPE_struct) {
+        if (TYPES[i].base_type == TYPE_struct ||
+            TYPES[i].base_type == TYPE_union) {
             if (flag == 1)
                 continue;
             if (!strcmp(TYPES[i].type_name, type_name))
@@ -1398,6 +1399,10 @@ void dump_bb_insn(func_t *func, basic_block_t *bb, bool *at_func_start)
             printf("%%%s = sign_ext %%%s, %d", rd->var_name, rs1->var_name,
                    insn->sz);
             break;
+        case OP_cast:
+            print_indent(1);
+            printf("%%%s = cast %%%s", rd->var_name, rs1->var_name);
+            break;
         default:
             printf("<Unsupported opcode: %d>", insn->opcode);
             break;