Re: [PATCH V2 8/9] tools/perf: Add support to find global register variables using find_data_type_global_reg

From: Christophe Leroy
Date: Tue May 07 2024 - 06:03:24 EST




Le 06/05/2024 à 14:19, Athira Rajeev a écrit :
> There are cases where define a global register variable and associate it
> with a specified register. Example, in powerpc, two registers are
> defined to represent variable:
> 1. r13: represents local_paca
> register struct paca_struct *local_paca asm("r13");
>
> 2. r1: represents stack_pointer
> register void *__stack_pointer asm("r1");

What about r2:

register struct task_struct *current asm ("r2");

>
> These regs are present in dwarf debug as DW_OP_reg as part of variables
> in the cu_die (compile unit). These are not present in die search done
> in the list of nested scopes since these are global register variables.
>