Hand-written assembly and Python API

[Jan Vrany <jan@vrany.io>]

Hi folks,

I'm trying to debug a code that uses a handful of
hand-written assembly routines. For example, one of
them looks like (its RISC-V but that does not matter):

    .text
    .globl returnFromJIT1
    .type returnFromJIT1,function
    .align 2
returnFromJIT1:
    .cfi_startproc
    sd a0,248(s10)
    sd s11,32(s10)
    li a0, 17
    li a1, 1
    j cInterpreterFromJIT
    .cfi_endproc
    .size   returnFromJIT1, .-returnFromJIT1

   .text
   .globl ...

GDB clealy knows "something" about the assembly routines, it shows
the source properly and 'info symbol' works too:

   (gdb) info symbol 0x3ff75eca24
   returnFromJIT1 in section .text of /opt/riscv/sysroot/tmp/jdk/lib/default/libj9jit29.so

The problem is how to figure out I'm in (say) `returnFromJIT1` routine
using Python API:

   (gdb) py print(gdb.block_for_pc(0x3ff75eca24).function)
   None

The only way I can think of is to parse value of `gdb.format_address()`:

   (gdb) py print(gdb.format_address(0x3ff75eca24))
   0x3ff75eca24 <returnFromJIT1>

which is bit awkward (but doable!).

Question is: is there a better way? I can modify the assembly source
too if there's some directive that may help GDB (.cfi_startproc / .cfi_endproc
is clearly not enough). Or do I have to roll up sleeves and implement python
API for minimal symbols?

Thanks!

Jan