support return stmt without result

2 files changed, 27 insertions, 2 deletions

diff --git a/main.c b/main.c
index 25d0274..bb80e4f 100644
--- a/main.c
+++ b/main.c
@@ -1063,6 +1063,11 @@ struct AstNode* parse_expr(struct Parser* p) {
 
 struct AstNode* parse_return_stmt(struct Parser* p) {
     expect(p, TK_K_RETURN);
+    if (peek_token(p)->kind == TK_SEMICOLON) {
+        next_token(p);
+        return ast_new(AST_RETURN_STMT);
+    }
+
     struct AstNode* expr = parse_expr(p);
     expect(p, TK_SEMICOLON);
 
@@ -1668,8 +1673,10 @@ void gen_return_stmt(struct CodeGen* g, struct AstNode* ast) {
     assert_ast_kind(ast, AST_RETURN_STMT);
     printf("  # gen_return_stmt\n");
 
-    gen_expr(g, ast->expr1, GEN_RVAL);
-    printf("  pop rax\n");
+    if (ast->expr1) {
+        gen_expr(g, ast->expr1, GEN_RVAL);
+        printf("  pop rax\n");
+    }
     gen_func_epilogue(g, ast);
 }
 
diff --git a/tests/037.sh b/tests/037.sh
new file mode 100644
index 0000000..bc6867b
--- /dev/null
+++ b/tests/037.sh
@@ -0,0 +1,18 @@
+set -e
+
+cat <<'EOF' > expected
+hi
+EOF
+bash ../../test_diff.sh <<'EOF'
+int printf();
+
+void f() {
+    printf("hi\n");
+    return;
+}
+
+int main() {
+    f();
+    return 0;
+}
+EOF