Implement aligned_alloc().

Implement aligned_alloc(), which was added in the C11 standard.  The
function is weakly specified to the point that a minimally compliant
implementation would be painful to use (size must be an integral
multiple of alignment!), which in practice makes posix_memalign() a
safer choice.

test/aligned_alloc.c

@@ -0,0 +1,123 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#define	JEMALLOC_MANGLE
+#include "jemalloc_test.h"
+
+#define CHUNK 0x400000
+/* #define MAXALIGN ((size_t)UINT64_C(0x80000000000)) */
+#define MAXALIGN ((size_t)0x2000000LU)
+#define NITER 4
+
+int
+main(void)
+{
+	size_t alignment, size, total;
+	unsigned i;
+	void *p, *ps[NITER];
+
+	fprintf(stderr, "Test begin\n");
+
+	/* Test error conditions. */
+	alignment = 0;
+	errno = 0;
+	p = aligned_alloc(alignment, 1);
+	if (p != NULL || errno != EINVAL) {
+		fprintf(stderr,
+		    "Expected error for invalid alignment %zu\n", alignment);
+	}
+
+	for (alignment = sizeof(size_t); alignment < MAXALIGN;
+	    alignment <<= 1) {
+		errno = 0;
+		p = aligned_alloc(alignment + 1, 1);
+		if (p != NULL || errno != EINVAL) {
+			fprintf(stderr,
+			    "Expected error for invalid alignment %zu\n",
+			    alignment + 1);
+		}
+	}
+
+#if LG_SIZEOF_PTR == 3
+	alignment = UINT64_C(0x8000000000000000);
+	size      = UINT64_C(0x8000000000000000);
+#else
+	alignment = 0x80000000LU;
+	size      = 0x80000000LU;
+#endif
+	errno = 0;
+	p = aligned_alloc(alignment, size);
+	if (p != NULL || errno != ENOMEM) {
+		fprintf(stderr,
+		    "Expected error for aligned_alloc(%zu, %zu)\n",
+		    alignment, size);
+	}
+
+#if LG_SIZEOF_PTR == 3
+	alignment = UINT64_C(0x4000000000000000);
+	size      = UINT64_C(0x8400000000000001);
+#else
+	alignment = 0x40000000LU;
+	size      = 0x84000001LU;
+#endif
+	errno = 0;
+	p = aligned_alloc(alignment, size);
+	if (p != NULL || errno != ENOMEM) {
+		fprintf(stderr,
+		    "Expected error for aligned_alloc(%zu, %zu)\n",
+		    alignment, size);
+	}
+
+	alignment = 0x10LU;
+#if LG_SIZEOF_PTR == 3
+	size = UINT64_C(0xfffffffffffffff0);
+#else
+	size = 0xfffffff0LU;
+#endif
+	errno = 0;
+	p = aligned_alloc(alignment, size);
+	if (p != NULL || errno != ENOMEM) {
+		fprintf(stderr,
+		    "Expected error for aligned_alloc(&p, %zu, %zu)\n",
+		    alignment, size);
+	}
+
+	for (i = 0; i < NITER; i++)
+		ps[i] = NULL;
+
+	for (alignment = 8;
+	    alignment <= MAXALIGN;
+	    alignment <<= 1) {
+		total = 0;
+		fprintf(stderr, "Alignment: %zu\n", alignment);
+		for (size = 1;
+		    size < 3 * alignment && size < (1U << 31);
+		    size += (alignment >> (LG_SIZEOF_PTR-1)) - 1) {
+			for (i = 0; i < NITER; i++) {
+				ps[i] = aligned_alloc(alignment, size);
+				if (ps[i] == NULL) {
+					fprintf(stderr,
+					    "Error for size %zu (%#zx): %s\n",
+					    size, size, strerror(errno));
+					exit(1);
+				}
+				total += malloc_usable_size(ps[i]);
+				if (total >= (MAXALIGN << 1))
+					break;
+			}
+			for (i = 0; i < NITER; i++) {
+				if (ps[i] != NULL) {
+					free(ps[i]);
+					ps[i] = NULL;
+				}
+			}
+		}
+	}
+
+	fprintf(stderr, "Test end\n");
+	return (0);
+}

test/aligned_alloc.exp

@@ -0,0 +1,25 @@
+Test begin
+Alignment: 8
+Alignment: 16
+Alignment: 32
+Alignment: 64
+Alignment: 128
+Alignment: 256
+Alignment: 512
+Alignment: 1024
+Alignment: 2048
+Alignment: 4096
+Alignment: 8192
+Alignment: 16384
+Alignment: 32768
+Alignment: 65536
+Alignment: 131072
+Alignment: 262144
+Alignment: 524288
+Alignment: 1048576
+Alignment: 2097152
+Alignment: 4194304
+Alignment: 8388608
+Alignment: 16777216
+Alignment: 33554432
+Test end