runtime/Auto.subproj/objc-auto-x86_64.s

   1 /*
   2  * Copyright (c) 2006-2007 Apple Inc.  All Rights Reserved.
   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  */
  23
  24 #ifdef __x86_64__
  25
  26 /*
  27     This file defines the non-GC variants of objc_assign_* on a dedicated
  28     page in the (__DATA,__data) section. At load time under GC, each
  29     routine is overwritten with a jump to its GC variant. It is necessary
  30     for these routines to exist on a dedicated page for vm_protect to
  31     work properly in the GC case. The page exists in the data segment to
  32     reduce the kernel's page table overhead.
  33
  34     Note: To avoid wasting more space than necessary at runtime, this file
  35     must not contain anything other than the objc_assign_* routines.
  36 */
  37
  38 .data
  39 .align 12   // align to page boundary
  40
  41 LNonGCAssigns$Begin:
  42
  43 // id objc_assign_ivar(id value, id dest, ptrdiff_t offset);
  44 .globl  _objc_assign_ivar
  45 _objc_assign_ivar:
  46     pushq   %rbp
  47     movq    %rsp,%rbp
  48     movq    %rdi,(%rsi,%rdx)    // *(dest + offset) = value);
  49     movq    %rdi,%rax           // return value;
  50     leave
  51     ret
  52
  53 // id objc_assign_global(id value, id *dest);
  54 .globl  _objc_assign_global
  55 _objc_assign_global:
  56     pushq   %rbp
  57     movq    %rsp,%rbp
  58     movq    %rdi,(%rsi)     // *(dest = value);
  59     movq    %rdi,%rax       // return value;
  60     leave
  61     ret
  62
  63 // As of OS X 10.5, objc_assign_strongCast_non_gc is identical to
  64 // objc_assign_global_non_gc.
  65
  66 // id objc_assign_strongCast(id value, id *dest);
  67 .globl  _objc_assign_strongCast
  68 _objc_assign_strongCast:
  69     pushq   %rbp
  70     movq    %rsp,%rbp
  71     movq    %rdi,(%rsi)     // *(dest = value);
  72     movq    %rdi,%rax       // return value;
  73     leave
  74     ret
  75
  76 LNonGCAssigns$End:
  77
  78 // Claim the remainder of the page.
  79 .set    L$set$assignsSize,LNonGCAssigns$End-LNonGCAssigns$Begin
  80 .space  4096-L$set$assignsSize
  81
  82 #endif