ref: 698837e7150af19ff6a3f0bf2144dffc81202a55
parent: 446e454c5a19d1ce2e8da699686159b3a31e8bc7
author: Ori Bernstein <[email protected]>
date: Mon Mar 9 04:02:22 EDT 2020
fix alignment in ape malloc We used to have a padding int in the structure after the next pointer, to align it to 16 bytes. On 64 bit architectures, the pointer was already 8 bits, so the padding misaligned things to 20 bytes. This fixes it so that we're explcit about the data alignment we want, instead of hoping that the various sizes line up.
--- a/sys/src/ape/lib/ap/plan9/malloc.c
+++ b/sys/src/ape/lib/ap/plan9/malloc.c
@@ -11,13 +11,22 @@
CUTOFF = 12,
};
+#define NPAD(t, align) \
+ ((sizeof(t) + align - 1) & ~(align - 1))
typedef struct Bucket Bucket;
-struct Bucket
-{+typedef struct Header Header;
+struct Header {int size;
int magic;
Bucket *next;
- int pad;
+};
+
+struct Bucket
+{+ union {+ Header;
+ char _pad[NPAD(Header, 16)];
+ };
char data[1];
};