git.saurik.com Git - apple/dyld.git/blob - unit-tests/test-cases/prebased-performance/foo.c

1 /*

3 *

4 * @APPLE_LICENSE_HEADER_START@

5 *

6 * This file contains Original Code and/or Modifications of Original Code

7 * as defined in and that are subject to the Apple Public Source License

8 * Version 2.0 (the 'License'). You may not use this file except in

9 * compliance with the License. Please obtain a copy of the License at

10 * http://www.opensource.apple.com/apsl/ and read it before using this

11 * file.

12 *

13 * The Original Code and all software distributed under the License are

14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER

15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,

16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,

17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.

18 * Please see the License for the specific language governing rights and

19 * limitations under the License.

20 *

21 * @APPLE_LICENSE_HEADER_END@

22 */

24 #include <stdbool.h>

25 #include <stdint.h>

26 #include <stdio.h>

27 #include <sys/types.h>

28 #include <unistd.h>

29 #include <mach/mach.h>

31 struct page

32 {

33 struct page* other;

         char                    pad[4096-sizeof(void*)];

35 };

38 struct page p1 = { &p1 };

39 struct page p2 = { &p1 };

40 struct page p3 = { &p1 };

41 struct page p4 = { &p1 };

42 struct page p5 = { &p1 };

43 struct page p6 = { &p1 };

44 struct page p7 = { &p1 };

45 struct page p8 = { &p1 };

46 struct page p9 = { &p1 };

47 struct page p10 = { &p1 };

49 //

50 // This dylib has 10 pages of data and each page will be adjusted

51 // by dyld if this dylib is not loaded at its preferred address.

52 //

53 bool checkRebasing()

54 {

55 int dirtyPageCount = 0;

         vm_address_t start = (((uintptr_t)&p1) + 4095) & (-4096);

         vm_address_t end = (((uintptr_t)&p10) + 4095) & (-4096);

58 task_port_t task;

         task_for_pid(mach_task_self(), getpid(), &task);

         for (vm_address_t addr = start; addr < end; addr += 4096) {

62 integer_t disposition = 0;

63 integer_t ref_count = 0;

                 vm_map_page_query(task, start, &disposition, &ref_count);

65 if ( disposition & VM_PAGE_QUERY_PAGE_DIRTY )

66 ++dirtyPageCount;

67 }

69 //fprintf(stderr, "dirtyPageCount=%d\n", dirtyPageCount);

71 // if there are too many dirty pages, then dyld is inefficient

         return ( dirtyPageCount < 2 );

73 }