objc反汇编分析，手工逆向libsystem_blocks.dylib

上一篇《block函数块为何物？》介绍了在函数中定义的block函数块的反汇编实现，我在文中再三指出__block变量和block函数块自始还都是stack-based的，还不完全适合在离开定义它们的范围之外使用，包括异步回调。本篇贴上我手工逆向的函数

libsystem_blocks.dylib`_Block_copy_internal。从名字可以看出blocks编程由系统提供的编程框架，_Block_copy_internal也就是block函数块的copy方法，是令block函数块适合用于异步回调必要的操作。

NSStackBlock的逆向定义请参考上一篇《block函数块为何物？》，下面是函数的逆向Ｃ＋＋代码：

附上逆向时参照的反汇编片段快照：

libsystem_blocks.dylib`_Block_copy_internal:
    0x10ce28458 <+>:   pushq  %rbp
    0x10ce28459 <+>:   movq   %rsp, %rbp
    0x10ce2845c <+>:   pushq  %r15
    0x10ce2845e <+>:   pushq  %r14
    0x10ce28460 <+>:   pushq  %r13
    0x10ce28462 <+>:  pushq  %r12
    0x10ce28464 <+>:  pushq  %rbx
    0x10ce28465 <+>:  pushq  %rax
    0x10ce28466 <+>:  movq   %rdi, %rbx
    0x10ce28469 <+>:  xorl   %eax, %eax
    0x10ce2846b <+>:  testq  %rbx, %rbx
    0x10ce2846e <+>:  je     0x10ce28534               ; <+220>
    0x10ce28474 <+>:  leaq   0x8(%rbx), %rcx
    0x10ce28478 <+>:  testl  $0x1000000, 0x8(%rbx)
    0x10ce2847f <+>:  jne    0x10ce284db               ; <+131>
    0x10ce28481 <+>:  testl  $0x8000000, (%rcx)
    0x10ce28487 <+>:  jne    0x10ce284f8               ; <+160>
    0x10ce28489 <+>:  testl  $0x10000000, (%rcx)
    0x10ce2848f <+>:  jne    0x10ce28531               ; <+217>
    0x10ce28495 <+>:  movb   0xbad(%rip), %al          ; isGC
    0x10ce2849b <+>:  testb  %al, %al
    0x10ce2849d <+>:  je     0x10ce28543               ; <+235>
    0x10ce284a3 <+>:  movl   0x8(%rbx), %r13d
    0x10ce284a7 <+>:  movl   %r13d, %r12d
    0x10ce284aa <+>:  andl   $0x4000000, %r12d
    0x10ce284b1 <+>:  movq   0xb48(%rip), %r8          ; _Block_allocator
    0x10ce284b8 <+>:  movq   0x18(%rbx), %rax
    0x10ce284bc <+>: movq   0x8(%rax), %rdi
    0x10ce284c0 <+>: movb   $0x1, %dl
    0x10ce284c2 <+>: jne    0x10ce285b8               ; <+352>
    0x10ce284c8 <+>: testl  $0x40000000, (%rcx)
    0x10ce284ce <+>: jne    0x10ce285a2               ; <+330>
    0x10ce284d4 <+>: xorl   %edx, %edx
    0x10ce284d6 <+>: jmp    0x10ce285b8               ; <+352>
    0x10ce284db <+>: movl   (%rcx), %eax
    0x10ce284dd <+>: movl   %eax, %edx
    0x10ce284df <+>: andl   $0xfffe, %edx
    0x10ce284e5 <+>: cmpl   $0xfffe, %edx
    0x10ce284eb <+>: je     0x10ce28531               ; <+217>
    0x10ce284ed <+>: leal   0x2(%rax), %edx
    0x10ce284f0 <+>: lock
    0x10ce284f1 <+>: cmpxchgl %edx, (%rcx)
    0x10ce284f4 <+>: jne    0x10ce284db               ; <+131>
    0x10ce284f6 <+>: jmp    0x10ce28531               ; <+217>
    0x10ce284f8 <+>: testb  %sil, %sil
    0x10ce284fb <+>: je     0x10ce28531               ; <+217>
    0x10ce284fd <+>: movl   (%rcx), %eax
    0x10ce284ff <+>: movl   %eax, %edx
    0x10ce28501 <+>: andl   $0xfffe, %edx
    0x10ce28507 <+>: cmpl   $0xfffe, %edx
    0x10ce2850d <+>: je     0x10ce28531               ; <+217>
    0x10ce2850f <+>: leal   0x2(%rax), %edx
    0x10ce28512 <+>: lock
    0x10ce28513 <+>: cmpxchgl %edx, (%rcx)
    0x10ce28516 <+>: jne    0x10ce284fd               ; <+165>
    0x10ce28518 <+>: andl   $0xfffe, %edx
    0x10ce2851e <+>: cmpl   $0x2, %edx
    0x10ce28521 <+>: jne    0x10ce28531               ; <+217>
    0x10ce28523 <+>: movl   $0x1, %esi
    0x10ce28528 <+>: movq   %rbx, %rdi
    0x10ce2852b <+>: callq  *0xae7(%rip)              ; _Block_setHasRefcount
    0x10ce28531 <+>: movq   %rbx, %rax
    0x10ce28534 <+>: addq   $0x8, %rsp
    0x10ce28538 <+>: popq   %rbx
    0x10ce28539 <+>: popq   %r12
    0x10ce2853b <+>: popq   %r13
    0x10ce2853d <+>: popq   %r14
    0x10ce2853f <+>: popq   %r15
    0x10ce28541 <+>: popq   %rbp
    0x10ce28542 <+>: retq
    0x10ce28543 <+>: movq   0x18(%rbx), %r15
    0x10ce28547 <+>: movq   0x8(%r15), %rdi
    0x10ce2854b <+>: callq  0x10ce28b34               ; symbol stub for: malloc
    0x10ce28550 <+>: movq   %rax, %r14
    0x10ce28553 <+>: xorl   %eax, %eax
    0x10ce28555 <+>: testq  %r14, %r14
    0x10ce28558 <+>: je     0x10ce28534               ; <+220>
    0x10ce2855a <+>: movq   0x8(%r15), %rdx
    0x10ce2855e <+>: movq   %r14, %rdi
    0x10ce28561 <+>: movq   %rbx, %rsi
    0x10ce28564 <+>: callq  0x10ce28b52               ; symbol stub for: memmove
    0x10ce28569 <+>: andl   $0xffff0000, 0x8(%r14)
    0x10ce28571 <+>: orl    $0x1000002, 0x8(%r14)
    0x10ce28579 <+>: leaq   0xbd0(%rip), %rax         ; _NSConcreteMallocBlock
    0x10ce28580 <+>: movq   %rax, (%r14)
    0x10ce28583 <+>: testl  $0x2000000, 0x8(%rbx)
    0x10ce2858a <+>: je     0x10ce28629               ; <+465>
    0x10ce28590 <+>: movq   0x18(%rbx), %rax
    0x10ce28594 <+>: movq   %r14, %rdi
    0x10ce28597 <+>: movq   %rbx, %rsi
    0x10ce2859a <+>: callq  *0x10(%rax)
    0x10ce2859d <+>: jmp    0x10ce28629               ; <+465>
    0x10ce285a2 <+>: leaq   0x10(%rax), %rdx
    0x10ce285a6 <+>: testl  $0x2000000, (%rcx)
    0x10ce285ac <+>: cmoveq %rax, %rdx
    0x10ce285b0 <+>: cmpq   $0x0, 0x18(%rdx)
    0x10ce285b5 <+>: setne  %dl
    0x10ce285b8 <+>: movzbl %sil, %r15d
    0x10ce285bc <+>: movzbl %dl, %edx
    0x10ce285bf <+>: movl   %r15d, %esi
    0x10ce285c2 <+>: callq  *%r8
    0x10ce285c5 <+>: movq   %rax, %r14
    0x10ce285c8 <+>: xorl   %eax, %eax
    0x10ce285ca <+>: testq  %r14, %r14
    0x10ce285cd <+>: je     0x10ce28534               ; <+220>
    0x10ce285d3 <+>: movq   0x18(%rbx), %rax
    0x10ce285d7 <+>: movq   0x8(%rax), %rdx
    0x10ce285db <+>: movq   %r14, %rdi
    0x10ce285de <+>: movq   %rbx, %rsi
    0x10ce285e1 <+>: callq  0x10ce28b52               ; symbol stub for: memmove
    0x10ce285e6 <+>: andl   $0xf6ff0000, %r13d
    0x10ce285ed <+>: addl   %r15d, %r15d
    0x10ce285f0 <+>: orl    %r13d, %r15d
    0x10ce285f3 <+>: orl    $0x8000000, %r15d
    0x10ce285fa <+>: movl   %r15d, 0x8(%r14)
    0x10ce285fe <+>: testl  $0x2000000, 0x8(%rbx)
    0x10ce28605 <+>: je     0x10ce28614               ; <+444>
    0x10ce28607 <+>: movq   0x18(%rbx), %rax
    0x10ce2860b <+>: movq   %r14, %rdi
    0x10ce2860e <+>: movq   %rbx, %rsi
    0x10ce28611 <+>: callq  *0x10(%rax)
    0x10ce28614 <+>: testl  %r12d, %r12d
    0x10ce28617 <+>: leaq   0xc32(%rip), %rax         ; _NSConcreteAutoBlock
    0x10ce2861e <+>: cmovneq 0x19ea(%rip), %rax        ; (void *)0x000000010ce29350: _NSConcreteFinalizingBlock
    0x10ce28626 <+>: movq   %rax, (%r14)
    0x10ce28629 <+>: movq   %r14, %rax
    0x10ce2862c <+>: jmp    0x10ce28534               ; <+220>

PS:博客园图片服务器不正常工作，数据上传后服务器返回http500，园方怡慢，迟迟还没解决。在此先占个placehoder。待园方解决问题后再上图。