From be7b759113e76223025cd025cf0172849385b444 Mon Sep 17 00:00:00 2001
From: nsfisis <nsfisis@gmail.com>
Date: Sat, 2 Aug 2025 02:03:20 +0900
Subject: feat: support sizeof() for variables

---
 parse.c      | 13 ++++++++++++-
 tests/076.sh | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 tests/076.sh

diff --git a/parse.c b/parse.c
index b1e65d4..b8ad901 100644
--- a/parse.c
+++ b/parse.c
@@ -403,7 +403,18 @@ AstNode* parse_prefix_expr(Parser* p) {
     } else if (op == TokenKind_keyword_sizeof) {
         next_token(p);
         expect(p, TokenKind_paren_l);
-        Type* ty = parse_type(p);
+        Token* next_tok = peek_token(p);
+        Type* ty = NULL;
+        if (next_tok->kind == TokenKind_ident) {
+            int lvar_idx = find_lvar(p, &next_tok->raw);
+            if (lvar_idx != -1) {
+                next_token(p);
+                ty = p->lvars[lvar_idx].ty;
+            }
+        }
+        if (!ty) {
+            ty = parse_type(p);
+        }
         expect(p, TokenKind_paren_r);
         return ast_new_int(type_sizeof(ty));
     }
diff --git a/tests/076.sh b/tests/076.sh
new file mode 100644
index 0000000..065094e
--- /dev/null
+++ b/tests/076.sh
@@ -0,0 +1,35 @@
+set -e
+
+cat <<'EOF' > expected
+sizeof(a) = 4
+sizeof(b) = 8
+sizeof(c) = 123
+sizeof(d) = 16
+sizeof(e) = 8
+sizeof(f) = 1968
+EOF
+bash ../../test_diff.sh <<'EOF'
+int printf();
+
+struct S {
+    long x;
+    long y;
+};
+
+int main() {
+    int a;
+    long b;
+    char c[123];
+    struct S d;
+    void* e;
+    struct S f[123];
+
+    printf("sizeof(a) = %d\n", sizeof(a));
+    printf("sizeof(b) = %d\n", sizeof(b));
+    printf("sizeof(c) = %d\n", sizeof(c));
+    printf("sizeof(d) = %d\n", sizeof(d));
+    printf("sizeof(e) = %d\n", sizeof(e));
+    printf("sizeof(f) = %d\n", sizeof(f));
+    return 0;
+}
+EOF
-- 
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