Hi Fangrui，

Modify some comment and

I change some part of a.c code accroding to my test case, and then the problem can be reproduced, please check the file{F27260437}.
Without this change, the back trace only get one layer.

I'm building and testing the code. After add test case will upload new patch. Thanks.

Delete the blank line

In D148499#4279283, @MaskRay wrote:

Do you know how to test this? The code looks reasonable, but I'd like to reproduce the issue... I may need a RISC-V image (with gcc,gdb,etc) which can run in qemu-system. On the non-riscv host I'll need some LLVM_ENABLE_RUNTIMES way to cross compile for RISC-V.

Set PC reg

Remove redundant assignments

Fix clang-format issue