Although the automatically inserted reload instruction in the `Epilogue`
is unrelated to the original code, in order to improve debugger
functionality, we have re-added debugging location information in the
reload instruction. When using an empty debugging location, the
following issue occurs:
```
loongson@linux:~$ cat -n test.c
1 int printf(const char *, ...);
2 int main(int argc, char **argv) {
3 printf("%d\n", argc);
4 return 0;
5 }
clang -g -O0 test.c -o test
```
Without this patch, the debugger is unable to correctly access the
current stack information when a breakpoint is set on line 4:
```
loongson@linux:~$ gdb -q ./test
Reading symbols from ./test...
(gdb) break 4
Breakpoint 1 at 0x7c0: file test.c, line 4.
(gdb) run
Starting program: /home/wanglei/test
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/loongarch64-linux-gnu/libthread_db.so.1".
1
Breakpoint 1, main (argc=<error reading variable: Cannot access memory at address 0xffffffffffffffe8>,
argv=<error reading variable: Cannot access memory at address 0xffffffffffffffe0>) at test.c:4
4 return 0;
```
Reviewed By: heiher, xen0n
Pull Request: https://github.com/llvm/llvm-project/pull/122057
5ae44bf718