From 9a34e3c5ce34662be956bdb1d0ad988316d16a94 Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Sun, 24 Mar 2024 01:20:19 -0700
Subject: decl: Check alignment range

We store alignment as int, so check that it fits to avoid
implementation-defined behavior.

Also, fix printf format specifier and drop unneeded parentheses.
---
 decl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/decl.c b/decl.c
index 98ac497..0a5cf6d 100644
--- a/decl.c
+++ b/decl.c
@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <limits.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -446,8 +447,8 @@ declspecs(struct scope *s, enum storageclass *sc, enum funcspec *fs, int *align)
 			expect(TLPAREN, "after 'alignas'");
 			other = typename(s, NULL);
 			i = other ? other->align : intconstexpr(s, false);
-			if (i & (i - 1))
-				error(&tok.loc, "invalid alignment: %d", i);
+			if (i & i - 1 || i > INT_MAX)
+				error(&tok.loc, "invalid alignment: %llu", i);
 			if (i > *align)
 				*align = i;
 			expect(TRPAREN, "to close 'alignas' specifier");
-- 
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