[M1 Mac, Big Sur 11.6.8, clang 13.0.0, NO IDE]
ポインタpのメモリ領域を確保して、空のままLLDBでその格納内容とメモリアドレスを確認しました。
正常なコードなので最終行で停止させ、printコマンドでポインタpのアドレスを出力しています。ついでにレジスタの状態や逆アセンブルを出力しました。
#include <cppstd.h>
int main() {
char *p;
p = (char*)malloc(sizeof(char));
printf("ポインタpが格納しているcharは %s\n", *p);
printf("ポインタpのアドレス(10進数)は %d\n", p);
printf("ポインタpのアドレス(16進数)は %x\n", p);
return 0;
}$ lldb -f test
(lldb) target create "test"
Current executable set to '/test' (arm64).
(lldb) b 12
Breakpoint 1: where = test`main + 120 at test.cpp:12:5, address = 0x0000000100003ed8
(lldb) r
Process 87108 launched: '/test' (arm64)
ポインタpが格納しているcharは (null)
ポインタpのアドレス(10進数)は 2125136
ポインタpのアドレス(16進数)は 206d50
Process 87108 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
frame #0: 0x0000000100003ed8 test`main at test.cpp:12:5
9 printf("ポインタpのアドレス(10進数)は %d\n", p);
10 printf("ポインタpのアドレス(16進数)は %x\n", p);
11
-> 12 return 0;
13 }
14
15
Target 0: (test) stopped.
(lldb) print p
(char *) $0 = 0x0000000100206d50 ""
(lldb) register read
General Purpose Registers:
x0 = 0x0000000000000000
x1 = 0x0000000000000000
x2 = 0x00000000000120a8
x3 = 0x0000000100808e31
x4 = 0x000000016fdff140
x5 = 0x000000016fdff540
x6 = 0x000000000000000a
x7 = 0x0000000000000000
x8 = 0x00000001000cbdec dyld`_main_thread + 172
x9 = 0x00000001ff69c8d0 libsystem_kernel.dylib`errno
x10 = 0x0000000000000002
x11 = 0x00000000fffffffd
x12 = 0x0000010000000000
x13 = 0x0000000000000000
x14 = 0x0000000000000000
x15 = 0x0000000000000000
x16 = 0x00000001942097d8 libsystem_kernel.dylib`__error
x17 = 0x0000000202cc5650 (void *)0x00000001942097d8: __error
x18 = 0x0000000000000000
x19 = 0x0000000000000000
x20 = 0x0000000000000000
x21 = 0x0000000000000000
x22 = 0x0000000000000000
x23 = 0x0000000000000000
x24 = 0x0000000000000000
x25 = 0x0000000000000000
x26 = 0x0000000000000000
x27 = 0x0000000000000000
x28 = 0x000000016fdff598
fp = 0x000000016fdff560
lr = 0x6310000100003ed4 (0x0000000100003ed4) test`main + 116 at test.cpp:10:5
sp = 0x000000016fdff540
pc = 0x0000000100003ed8 test`main + 120 at test.cpp:12:5
cpsr = 0x20000000
(lldb) di
test`main:
0x100003e60 <+0>: sub sp, sp, #0x30 ; =0x30
0x100003e64 <+4>: stp x29, x30, [sp, #0x20]
0x100003e68 <+8>: add x29, sp, #0x20 ; =0x20
0x100003e6c <+12>: mov w8, #0x0
0x100003e70 <+16>: str w8, [sp, #0xc]
0x100003e74 <+20>: stur wzr, [x29, #-0x4]
0x100003e78 <+24>: mov x0, #0x1
0x100003e7c <+28>: bl 0x100003ee4 ; symbol stub for: malloc
0x100003e80 <+32>: str x0, [sp, #0x10]
0x100003e84 <+36>: ldr x8, [sp, #0x10]
0x100003e88 <+40>: ldrsb w10, [x8]
0x100003e8c <+44>: adrp x0, 0
0x100003e90 <+48>: add x0, x0, #0xf2c ; =0xf2c
0x100003e94 <+52>: mov x9, sp
0x100003e98 <+56>: mov x8, x10
0x100003e9c <+60>: str x8, [x9]
0x100003ea0 <+64>: bl 0x100003ef0 ; symbol stub for: printf
0x100003ea4 <+68>: ldr x8, [sp, #0x10]
0x100003ea8 <+72>: adrp x0, 0
0x100003eac <+76>: add x0, x0, #0xf5a ; =0xf5a
0x100003eb0 <+80>: mov x9, sp
0x100003eb4 <+84>: str x8, [x9]
0x100003eb8 <+88>: bl 0x100003ef0 ; symbol stub for: printf
0x100003ebc <+92>: ldr x8, [sp, #0x10]
0x100003ec0 <+96>: adrp x0, 0
0x100003ec4 <+100>: add x0, x0, #0xf88 ; =0xf88
0x100003ec8 <+104>: mov x9, sp
0x100003ecc <+108>: str x8, [x9]
0x100003ed0 <+112>: bl 0x100003ef0 ; symbol stub for: printf
0x100003ed4 <+116>: ldr w0, [sp, #0xc]
-> 0x100003ed8 <+120>: ldp x29, x30, [sp, #0x20]
0x100003edc <+124>: add sp, sp, #0x30 ; =0x30
0x100003ee0 <+128>: ret
(lldb) exit
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