CKB VM Debug Utils

Utilities aiding CKB VM debug, including the following components:

• gdb remote debugging support
• standard IO components, so you can debug with printf as you wish

How to use it

While this library contains components to plugin to your CKB VM runtime, we also prepare a bare metal binary showcasing how to use the components. Notice for now this binary only runs simple RISC-V programs, it doesn't support syscalls used in CKB. Later we might combine this with ckb-standalone-debugger to create a unified debugging experience for CKB.

$ cat program.c
int power(int, int);

int main() {
  int i, result;

  for (i = 0; i < 10; i++) {
    result += power(2, i);
  }
  return result;
}

int power(int base, int n) {
  int i, p;
  p = 1;
  for (i = 1; i <= n; i++) p = p * base;
  return p;
}
$ git clone https://github.com/nervosnetwork/ckb-vm-debug-utils
$ cd ckb-vm-debug-utils
$ cargo build
$ riscv64-unknown-elf-gcc -g ../program.c -o program
$ ./target/debug/baremetal 0.0.0.0:2000 program

Now CKB VM's debug server has been started, in a different terminal, we can launch gdb:

$ cd ckb-vm-debug-utils
$ gdb program
(gdb) target remote localhost:2000
Remote debugging using localhost:2000
0x00000000000100c8 in _start ()
(gdb) b main
Breakpoint 1 at 0x101ba: file program.c, line 6.
(gdb) c
Continuing.

Breakpoint 1, main () at program.c:6
6         for (i = 0; i < 10; i++) {
(gdb) s
7           result += power(2, i);
(gdb) print i
$1 = 0
(gdb)

As we can see, gdb works here.