scc

commit cdd599b1db41f2983c446c0fdefb799afbb511eb
parent 42441dfa818cce4c67092948f8113fd1afef41ab
Author: Roberto E. Vargas Caballero <k0ga@shike2.net>
Date:   Mon,  2 Feb 2026 12:37:24 +0100

cc1: Fix padding in initializers

The alignment calculation was wrong and it generated static struct and arrays
with data misplaced.

Diffstat:
M
src/cmd/scc-cc/cc1/code.c
 | 
17
+++++++++--------
A
tests/cc/execute/0238-align.c
 | 
20
++++++++++++++++++++
M
tests/cc/execute/scc-tests.lst
 | 
3
++-

3 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/src/cmd/scc-cc/cc1/code.c b/src/cmd/scc-cc/cc1/code.c
@@ -353,18 +353,19 @@ zeronode(Type *tp)
 	return simplify(convert(constnode(zero), tp, 0));
 }
 
-static int
+static void
 emitpadding(Type *tp, unsigned long long *addr)
 {
-	int i;
-	unsigned long long n;
+	int i, align;
+	unsigned long long a, n;
 
-	n = *addr & tp->align-1;
-	for (i = 0; i < n; i++)
-		emitexp(OEXPR, zeronode(chartype));
-	*addr += n;
+	align = tp->align - 1;
+	a = *addr;
+	n = a+align & ~align;
 
-	return n;
+	for ( ; a != n; ++a)
+		emitexp(OEXPR, zeronode(chartype));
+	*addr = n;
 }
 
 static void
diff --git a/tests/cc/execute/0238-align.c b/tests/cc/execute/0238-align.c
@@ -0,0 +1,20 @@
+struct a {
+	char c;
+	int i;
+};
+
+int
+main(void)
+{
+	struct a s[2] = {
+		{.c = 64, .i = 3},
+		{.c = 64, .i = 6}
+	};
+
+	if (s[0].i != 3)
+		return 1;
+	if (s[1].i != 6)
+		return 2;
+
+	return 0;
+}
diff --git a/tests/cc/execute/scc-tests.lst b/tests/cc/execute/scc-tests.lst
@@ -208,7 +208,7 @@
 0215-ret_struct.c
 0216-initialize.c [TODO]
 0217-lchar.c
-0218-initialize.c [TODO]
+0218-initialize.c
 0219-abbrev.c
 0220-comma.c
 0221-ifdef.c
@@ -228,3 +228,4 @@
 0235-comment.c
 0236-sizeof.c
 0237-down.c
+0238-align.c