From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <jan@vrany.io>
Received: from mail-4317.proton.ch (mail-4317.proton.ch [185.70.43.17])
 by sourceware.org (Postfix) with ESMTPS id DACDC3856DC4
 for <gdb@sourceware.org>; Fri, 29 Apr 2022 12:32:59 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org DACDC3856DC4
Date: Fri, 29 Apr 2022 12:32:49 +0000
To: GDB mailing list <gdb@sourceware.org>
From: Jan Vrany <jan@vrany.io>
Reply-To: Jan Vrany <jan@vrany.io>
Subject: Hand-written assembly and Python API
Message-ID: <5dce3fb2110facb58974d1ee546c43b6db20b6f4.camel@vrany.io>
Feedback-ID: 40767693:user:proton
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
X-Spam-Status: No, score=-3.2 required=5.0 tests=BAYES_00, DKIM_SIGNED,
 DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, SPF_HELO_NONE, SPF_PASS,
 TXREP autolearn=ham autolearn_force=no version=3.4.4
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on
 server2.sourceware.org
X-BeenThere: gdb@sourceware.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gdb mailing list <gdb.sourceware.org>
List-Unsubscribe: <https://sourceware.org/mailman/options/gdb>,
 <mailto:gdb-request@sourceware.org?subject=unsubscribe>
List-Archive: <https://sourceware.org/pipermail/gdb/>
List-Post: <mailto:gdb@sourceware.org>
List-Help: <mailto:gdb-request@sourceware.org?subject=help>
List-Subscribe: <https://sourceware.org/mailman/listinfo/gdb>,
 <mailto:gdb-request@sourceware.org?subject=subscribe>
X-List-Received-Date: Fri, 29 Apr 2022 12:33:03 -0000

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/defaul=
t/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_endp=
roc
is clearly not enough). Or do I have to roll up sleeves and implement pytho=
n
API for minimal symbols?

Thanks!

Jan