debug可执行文件时出现段错误

[yilin0518]

我debug的可执行文件时public文件夹下的sort_test7,在执行这个文件的时候出现了段错误。经过我debug，发现该错误出现在该文件的tea代码中MergeSort函数在if循环中第一次调用自身这个位置。我把生成的汇编代码仔仔细细的看了一遍，并把大部分过程中目标寄存器的值进行了注释标注，发现实际运行逻辑并没有问题，但是问题出现段错误的地方是第一次调用自身的ldp x29, x30, [sp], #16 这个地方。下面我给出对应该函数的汇编代码，并给出gdb的调试出现错误的位置：

(gdb)  x/10i $pc
=> 0x400c30 <bb25+88>:  ldp     x29, x30, [sp], #16
   0x400c34 <bb25+92>:  ldr     x15, [sp], #8
   0x400c38 <bb25+96>:  ldp     x13, x14, [sp], #16
   0x400c3c <bb25+100>: ldp     x11, x12, [sp], #16
   0x400c40 <bb25+104>: ldp     x9, x10, [sp], #16
   0x400c44 <bb25+108>: mov     x9, x0
   0x400c48 <bb25+112>: mov     x9, x13
   0x400c4c <bb25+116>: mov     x10, #0x1                       // #1
   0x400c50 <bb25+120>: add     x9, x9, x10
   0x400c54 <bb25+124>: mov     x10, x9

MergeSort:

        //bb24:

bb24:

        //  %r390 = add i32 0, 0

        mov     x16, #0
        sub     sp, sp, x16
        mov     x12, x0 //array
        mov     x11, x1 //p
        mov     x10, x2 //q
        mov     x9, #0
        mov     x13, x9
        //  %r391 = add i32 0, 0

        mov     x9, #0
        mov     x15, x9
        //  %r392 = add i32 0, 0

        mov     x9, #0
        //  %r393 = add i32 %r241, 0

        mov     x11, x11
        //  %r394 = add i32 0, 0

        mov     x9, #0
        //  %r395 = add i32 %r243, 0

        mov     x14, x10
        //  %r247 = add i32 %r393, 0

        mov     x9, x11
        //  %r249 = add i32 %r395, 0

        mov     x10, x14
        //  %r245 = icmp slt i32 %r247, %r249

        cmp     x9, x10
        //  br i1 %r245, label %bb25, label %bb26

        b.lt     bb25
        b     bb26
        //bb25:

bb25:

        //  %r252 = add i32 %r393, 0

        mov     x9, x11 //p
        //  %r254 = add i32 %r395, 0

        mov     x10, x14 //q
        //  %r255 = add i32 %r252, %r254

        add     x9, x9, x10 //p+q
        //  %r256 = sdiv i32 %r255, 2

        mov     x10, #2
        sdiv     x9, x9, x10 //(p+q)/2
        //  %r398 = add i32 %r256, 0

        mov     x13, x9 //(p+q)/2
        //  %r261 = getelementptr i32, i32* %r240, i32 0

        mov     x9, #0
        mov     x10, #8
        mul     x9, x9, x10
        add     x9, x12, x9 //array
        //  %r263 = add i32 %r393, 0

        mov     x10, x11        //p        
        //  %r265 = add i32 %r398, 0

        mov     x15, x13 //(p+q)/2
        //  %r259 = call i32 @MergeSort(i32* %r261, i32 %r263, i32 %r265)

        mov     x0, x9
        mov     x1, x10
        mov     x2, x15
        stp     x9, x10, [sp, #-16]!
        stp     x11, x12, [sp, #-16]!
        stp     x13, x14, [sp, #-16]!
        str     x15, [sp, #-8]!
        stp     x29, x30, [sp, #-16]!
        mov     x29, sp
        bl     MergeSort
        ldp     x29, x30, [sp], #16                  //在此处出现了段错误
        ldr     x15, [sp], #8
        ldp     x13, x14, [sp], #16
        ldp     x11, x12, [sp], #16
        ldp     x9, x10, [sp], #16
        mov     x9, x0  //return value ,is 0
        //  %r399 = add i32 %r259, 0

        //  %r267 = add i32 %r398, 0

        mov     x9, x13 //(p+q)/2
        //  %r268 = add i32 %r267, 1

        mov     x10, #1
        add     x9, x9, x10 //(p+q)/2+1
        //  %r400 = add i32 %r268, 0

        mov     x10, x9     //(p+q)/2+1
        //  %r272 = getelementptr i32, i32* %r240, i32 0

        mov     x9, #0  
        mov     x15, #8
        mul     x9, x9, x15
        add     x15, x12, x9 //array
        //  %r274 = add i32 %r400, 0

        mov     x10, x10
        //  %r276 = add i32 %r395, 0

        mov     x9, x14 //q
        //  %r270 = call i32 @MergeSort(i32* %r272, i32 %r274, i32 %r276)

        mov     x0, x15 //array
        mov     x1, x10 //(p+q)/2+1 = tmp
        mov     x2, x9  //q
        stp     x9, x10, [sp, #-16]!
        stp     x11, x12, [sp, #-16]!
        stp     x13, x14, [sp, #-16]!
        str     x15, [sp, #-8]!
        stp     x29, x30, [sp, #-16]!
        mov     x29, sp
        bl     MergeSort
        ldp     x29, x30, [sp], #16
        ldr     x15, [sp], #8
        ldp     x13, x14, [sp], #16
        ldp     x11, x12, [sp], #16
        ldp     x9, x10, [sp], #16
        mov     x9, x0
        //  %r401 = add i32 %r270, 0

        //  %r280 = getelementptr i32, i32* %r240, i32 0

        mov     x9, #0
        mov     x10, #8
        mul     x9, x9, x10
        add     x12, x12, x9
        //  %r282 = add i32 %r393, 0

        mov     x11, x11
        //  %r284 = add i32 %r398, 0

        mov     x10, x13
        //  %r286 = add i32 %r395, 0

        mov     x9, x14
        //  %r278 = call i32 @Merge(i32* %r280, i32 %r282, i32 %r284, i32 %r286)

        mov     x0, x12
        mov     x1, x11
        mov     x2, x10
        mov     x3, x9
        stp     x9, x10, [sp, #-16]!
        stp     x11, x12, [sp, #-16]!
        stp     x13, x14, [sp, #-16]!
        str     x15, [sp, #-8]!
        stp     x29, x30, [sp, #-16]!
        mov     x29, sp
        bl     Merge
        ldp     x29, x30, [sp], #16
        ldr     x15, [sp], #8
        ldp     x13, x14, [sp], #16
        ldp     x11, x12, [sp], #16
        ldp     x9, x10, [sp], #16
        mov     x9, x0
        //  %r402 = add i32 %r278, 0

        mov     x9, x9
        //  br label %bb27

        b     bb27
        //bb26:

bb26:

        //  br label %bb27

        b     bb27
        //bb27:

bb27:

        //  %r396 = phi i32 [ %r402, %bb25 ], [ %r390, %bb26 ]

        //  %r397 = phi i32 [ %r398, %bb25 ], [ %r391, %bb26 ]

        //  ret i32 0

        mov     x9, #0
        mov     x0, x9
        mov     sp, x29
        ret

[zhanghanxing2022]

猜测是Merge函数进行局部变量的数组操作时，出现了错误导致修改到了其他栈帧的寄存器，我看看你的Merge函数的fpoffset。