From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca (simark.ca [158.69.221.121]) by sourceware.org (Postfix) with ESMTPS id 34F73394800C for ; Fri, 29 Apr 2022 12:54:26 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 34F73394800C Received: from [172.16.0.95] (192-222-180-24.qc.cable.ebox.net [192.222.180.24]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id CC9241E00E; Fri, 29 Apr 2022 08:54:25 -0400 (EDT) Message-ID: Date: Fri, 29 Apr 2022 08:54:25 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: Hand-written assembly and Python API Content-Language: tl To: Jan Vrany , GDB mailing list References: <5dce3fb2110facb58974d1ee546c43b6db20b6f4.camel@vrany.io> From: Simon Marchi In-Reply-To: <5dce3fb2110facb58974d1ee546c43b6db20b6f4.camel@vrany.io> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, SPF_HELO_PASS, 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Apr 2022 12:54:27 -0000 On 2022-04-29 08:32, Jan Vrany via Gdb wrote: > 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 > > 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? I was going to say "returnFromJIT1" is a minimal symbol, but you clearly know that already. There is DWARF debug info for assembly when building with -g (at least when building with gcc / gas), but it only contains line statements, which allows GDB to show where you are in the source file (instead of showing disassembly). You won't be able to look up a block from that. I don't know of a way to do it with the current API, unfortunately. Simon