Date: Tue, 16 Feb 2021 10:34:25 -0300 From: "Dr. Rolf Jansen" <freebsd-rj@obsigna.com> To: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: LLDB on FreeBSD/arm64 and arm Message-ID: <9EDAF212-EA86-4AAC-97C6-BB801161DC4D@obsigna.com> In-Reply-To: <fd58349e0b352636a8444418227b9ea5318360da.camel@gentoo.org> References: <CAPyFy2A_E=fJwbRoL4uj4PvyeQ_Oz0v1xTOw3tkTQvJNfO3LbQ@mail.gmail.com> <E2CC3F9F-75DE-41F5-83BD-0179007583C2@obsigna.com> <fd58349e0b352636a8444418227b9ea5318360da.camel@gentoo.org>
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> Am 05.02.2021 um 13:40 schrieb Michał Górny <mgorny@gentoo.org>: >> On Fri, 2021-02-05 at 12:30 -0300, Dr. Rolf Jansen wrote: >>> Am 03.02.2021 um 14:53 schrieb Ed Maste <emaste@freebsd.org>: >>> >>> As you may know, the FreeBSD Foundation sponsored Moritz Systems to >>> improve LLDB's support of non-x86 FreeBSD targets (and some other >>> improvements applicable to all targets). This builds on their >>> earlier >>> work to update x86 support. >>> >>> Initial changes for arm64 and arm support were recently committed >>> upstream. Details are in these code reviews, if you're interested: >>> >>> https://reviews.llvm.org/D95297 (arm64) >>> https://reviews.llvm.org/D95696 (arm) >>> >>> arm and arm64 users with an interest in LLDB are encouraged to build >>> LLDB from the upstream git repository, try out the support, and >>> report >>> issues or positive results. >>> >>> It should build using the regular build process as described at >>> https://lldb.llvm.org/resources/build.html >>> >>> At present all four of 32- and 64-bit arm and x86 use LLDB's >>> non-legacy debug support by default. Legacy support will be removed >>> from LLDB upon completion of Moritz' work (once all architectures >>> are >>> patched) and there is no need to try out legacy support. >> >> I am interested to build LLDB from the upstream repository. As a >> matter of fact a few years ago I did this already directly on a >> BeagleBone Black, however in the meantime the LLVM sources had grown >> beyond the capacity a BBB could compile. Already at that time a rather >> limited build took more than 48 hs. >> >> I set up an ARMv7 cross building environment for kernel and world on a >> reasonably equipped i7 machine. Can I somehow use this for building >> LLDB as well? > > Yes. See our summary for some tips: > > https://www.moritz.systems/blog/freebsd-remote-process-plugin-on-non-x86-architectures/ > > Go for 'Cross-compiling LLVM'. On ARMv7, you'll have to change > the target and host triplets to armv7-unknown-freebsd13.0-gnueabihf > and LLVM target to ARM. > >> I provided ssh root access to one of my BBBs to Michał Górny for >> testing his work, and he left a LLDB on the system, I don't know at >> which stage, though. When debugging an advanced project of mine with >> this one I see some show stoppers (as with the original LLDB). >> Perhaps, I could be of help to improve LLDB. > > If it's about watchpoints, then we need to support them on kernel level > first. For anything else, we need to figure out what's wrong/missing. It took a while until I got it working - „too many variables, so few time“ In the toolchains file, I needed to add a definition for sysroot. When passing it with the C_FLAGS and CXX_FLAGS, I got typical 32 vs. 64 bit errors very early in the build process. Something like size_t is not long. The working toolchain file for ARMv7 is the following — <SYSROOT> is the placeholder for the actual path, here it is /root/install/BBB/sysroot: set(CMAKE_C_FLAGS "-target armv7-unknown-freebsd13.0-gnueabihf") set(CMAKE_CXX_FLAGS "-target armv7-unknown-freebsd13.0-gnueabihf") set(CMAKE_SYSROOT <SYSROOT>) set(CMAKE_SYSTEM_NAME "FreeBSD") set(CMAKE_FIND_ROOT_PATH <SYSROOT>) set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER) set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY) set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY) Before, I found this out, I meandered between versions of LLVM (I compiled 10.x, 11.x, 12.x and HEAD), and I switched to another build machine, before it was FreeBSD 12.2-RELEASE on a real i7 and now I build in a VM running FreeBSD 13.0-BETA2. However, without the definition of CMAKE_SYSROOT all this did not work out. Now I deployed a lldb to my BeagleBone running 13-BETA2 as well: lldb version 13.0.0 (https://github.com/llvm/llvm-project.git revision b40fde062c306584d88243de11175187e754ce3b) clang revision b40fde062c306584d88243de11175187e754ce3b llvm revision b40fde062c306584d88243de11175187e754ce3b I am able to debug simple programs, but the happiness ends already when trying to enter a subroutine. At least this worked well with lldb 11.0.1, which has been build by using in the course of world by WORLD_FLAGS="MK_LLDB=yes“. However both bail out, when I try to debug a bigger project of mine. (lldb) target create "./CyDaemon" Current executable set to '/root/install/CyDaemon/CyDaemon' (arm). (lldb) settings set -- target.run-args "-f" "-l" "80" "-s" "443" (lldb) r Process 767 launched: '/root/install/CyDaemon/CyDaemon' (arm) Process 767 stopped * thread #1, name = 'CyDaemon', stop reason = signal SIGILL: illegal instruction frame #0: 0x20290048 -> 0x20290048: vmull.p64 q0, d0, d0 0x2029004c: bx lr 0x20290050: ldr r0, [pc, #0x68] 0x20290054: add r1, pc, #100 (lldb) The question now is, how to continue from here? Do we continue? If yes, do we build on FreeBSD 13.0-RELEASE (BETAx for some more days) or do we build on 14-CURRENT? Which version of lldb do we debug? A release version or HEAD? The last lldb which worked absolutely well on the BBB was 3.9 or was it 4.x. I know, that I never got 5.x to compile on the BBB. However now, that my cross-building environment has been set up, I probably will check that as well. Best regards Rolfhome | help
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