gdb deletes watchpoint for local variables in scope

gdb deletes watchpoint for local variables in scope

[Varun Kumar Erigila]

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Hello everyone,
              Gdb complains saying "Watchpoint <number> deleted because the program has left the block in which its expression is valid", even though the local variable is still in scope for RISC-V architecture.
              Test Code: Compiler Explorer (godbolt.org)<https://godbolt.org/z/dhb5K5KK4>

               Code compiled with clang(trunk):

        *   clang -g -static -c program.c
        *   riscv64-unknown-elf-gcc program.o -o program -march=rv64imac -mabi=lp64

              Gdb(12.1):

  *   riscv64-unknown-elf-gdb program
  *   break main
  *   set can-use-hw-watchpoints 0
  *   watch q
  *   continue
  *   Watchpoint 2 deleted because the program has left the block in
  *   which its expression is valid.
  *   0x00000000000101e0 in func () at watch_cond.c:2

              Even though the variable q is still in scope in main, gdb prints this message immediately after func() returns.
               I'm trying to debug gdb on update_watchpoint function where this message is originating from.

               Any suggestions on why gdb is behaving so.

regards
Varun

Re: gdb deletes watchpoint for local variables in scope

[Simon Sobisch]

If you did not do that already try adding
    -O -ggdb
to your clang invocation.

Also:
* Does it make any difference if you compile with gcc?
* Does "print q" still return something - and the same as before
   "watch q"?

Simon