在lldb中将寄存器值设置为NSString

(lldb) register read
General Purpose Registers:
       rax = 0x0000000000000000
       rbx = 0x0000000000000000
       rcx = 0x0000000000007d0b
       rdx = 0x00007fffb6e40860  @"Helvetica"

现在,我试图以多种方式更改其值-我试图在“expression”中创建一个NSString对象,并将其设置为$rdx:

(lldb) expression
Enter expressions, then terminate with an empty line to evaluate:
  1: NSString *abc=@"Times"; 
  2: $rdx=abc;
error: assigning to 'unsigned long' from incompatible type 'NSString *'

(lldb) expression
Enter expressions, then terminate with an empty line to evaluate:
  1: NSString *abc=@"Times"; 
  2: $rdx=(unsigned long)&abc; 
(unsigned long) $110 = 123145406123008

现在,寄存器读取仅显示指针值,而不是NSString值

(lldb) register read 
General Purpose Registers:
       rax = 0x0000000000000000
       rbx = 0x0000000000000000
       rcx = 0x0000000000007d0b
       rdx = 0x000070000e275d00

现在我知道我遗漏了一些东西,因为rdx的初始值指向NSString(0x00007fffb6e40860)-当从内存中读取它时,它指向另一个指针(7fffb3d721b8,它指向垃圾数据…)

(lldb) memory read 0x00007fffb6e40860
0x7fffb6e40860: b8 21 d7 b3 ff 7f 00 00 c8 07 00 00 00 00 00 00  ?!׳?...?.......

在将rdx分配给NSString指针后读取值时,它确实会显示字符串值:

(lldb) memory read 0x000070000f8a3d00
0x70000f8a3d00: 55 54 69 6d 65 73 00 00 00 00 00 00 00 00 00 00  UTimes..........

如果不够清楚,我的目标是设置rdx,这样它会显示如下内容:

(lldb) register read
General Purpose Registers:
       rax = 0x0000000000000000
       rbx = 0x0000000000000000
       rcx = 0x0000000000007d0b
       rdx = 0x00007fffb6e40860  @"Times"