similar to: LLD Build Improvements

Hey LLVM folks, I've run into an interesting assertion. In one of HardenedBSD's feature branches, we're working on integration llvm's Cross-DSO CFI implementation. Using Cross-DSO CFI requires building libs with LTO, which causes clang to emit LLVM IR intermediate object files rather than ELF intermediate object files. I've found that with lld, attempting to link LLVM IR

Hey Peter, Here you go! https://hardenedbsd.org/~shawn/2018-11-28_reproduce-01.tar Thanks, -- Shawn Webb Cofounder and Security Engineer HardenedBSD Tor-ified Signal: +1 443-546-8752 Tor+XMPP+OTR: lattera at is.a.hacker.sx GPG Key ID: 0x6A84658F52456EEE GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89 3D9E 6A84 658F 5245 6EEE On Wed, Nov 28, 2018 at 05:30:57PM -0800, Peter

Thanks for providing the patch! I got around to testing it this morning and it appears it fixes compilation, but produces a non-working system. I know that's kinda vague and I'll have more details soon, including sample binaries. I at least wanted to give a status update so you didn't think you were being ignored. Thanks, -- Shawn Webb Cofounder and Security Engineer HardenedBSD

It's at this point where I think about filing a full bug report with llvm. Any hints before I do? On Mon, Jan 07, 2019 at 04:00:02PM -0500, Shawn Webb wrote: > It looks like this commit breaks CSU initialization with > statically-compiled applications. > > With a very simple application at [1], compiled with: > cc -g -O0 -flto -static -o pid pid.c > > The application

On Mon, Jun 24, 2019 at 3:37 PM Jake Ehrlich <jakehehrlich at google.com> wrote: > disclaimer: I work at Google so don't take my +1 as an independent vote > forward. > > We would like to use this on Fuchsia and I am particularly interested in > creating a dynamic linking library for ELF with Roland McGrath's guidance. > We spoke about creating a library for writing

Hi all, I'd like to make a proposal to implement the new vtable ABI described in PR26723, which I'll call the relative ABI. That bug gives more details and justification for that ABI. The user interface for the new ABI would be that -fwhole-program-vtables would take an optional value indicating which aspects of the program have whole-program scope. For example, the existing

On Tue, May 23, 2017 at 4:39 PM, Evgenii Stepanov <eugeni.stepanov at gmail.com > wrote: > On Tue, May 16, 2017 at 4:33 PM, Evgenii Stepanov > <eugeni.stepanov at gmail.com> wrote: > > On Mon, May 15, 2017 at 6:44 PM, Peter Collingbourne <peter at pcc.me.uk> > wrote: > >> Thanks for sending this out. A few comments below. > >> > >> On

Hi Rui, > but why don't you use lld-link (lld for Windows target) instead of ld.lld (lld for Unix target) to create UEFI applications? I need support both PE/COFF and ELF format tools. I’m also working on the lld-link enabling (clang-cl + lld-link) in both Linux and windows. The ld.lld enabling (clang + ld.lld) is for ELF format native users. E.g.

Hi Rui, A quick question: Does lld-link only work with clang-cl with windows-msvc option? Can lld-link work with clang with linux-gnu option? Thanks Steven Shi Intel\SSG\FID\Firmware Infrastructure From: Shi, Steven Sent: Tuesday, January 29, 2019 1:32 PM To: 'Rui Ueyama' <ruiu at google.com> Cc: llvm-dev at lists.llvm.org Subject: RE: lld write wrong symbol value in .data

Hello Vic, I don't have a lot to add myself. I think that majority of the input needs to come from the OS stakeholders. My main concern is if it requires work on every platform to take advantage or avoid regressions then perhaps it is worth adding as an option rather than changing the default. Some questions: - Does this need work in every OS for correctness of programs? For example you

+Peter Collingbourne <pcc at chromium.org> LTO is used in this test case, and one source file defines its own `memset` function while the other file uses llvm.memset. Looks like LTO is confused by the user-defined memset. Could you take a look? Steven, Do you need to use LTO? I thought that LTO is a workaround to not produce an object file that cannot be handled by your ELF-to-COFF

Hi, I've just tagged LLVM 9.0.1-rc3. Testers can begin testing and uploading binaries. This will be the last release candidate unless there is a major problem. I'm planning to tag the final release on Dec 19. -Tom

Hi Steven, One thing I noticed is that you are defining `memcpy`, which clang has an intrinsic with the same name. Can you try renaming it to a random name, like `foobar`, to see if the problem still exists? On Tue, Jul 16, 2019 at 10:10 AM Shi, Steven <steven.shi at intel.com> wrote: > I’ve submitted a BZ for this issue as below: > > > > Bug 42626 - lld-link crash when

lld should not crash in this case (so that's a bug that needs fixing), but setting it aside, did you try adding `-fno-builtin` to clang so that clang doesn't handle `memcpy` as a built-in function? On Tue, Jul 16, 2019 at 8:46 PM Shi, Steven <steven.shi at intel.com> wrote: > Hi Rui, > > For the test case in my previous email, if I change the `memcpy` to > `foobar` in

Hello Rui, I met couples of lld-link crash when enable the clang-cl + lld-link build toolchain for Uefi firmware. Below is a simplified example (main.c and intrinsics.c). Uefi firmware is self-contained and doesn't depend on the compiler intrinsics implementation, so we have our own intrinsics lib. It is weird that if I don't use the llvm-lib but directly "lld-link /NODEFAULTLIB

Hey all, TL;DR: Moving RELRO segment to be immediately after read-only segment so that the dynamic linker has the option to merge the two virtual memory areas at run time. This is an RFC for moving RELRO segment. Currently, lld orders ELF sections in the following order: R, RX, RWX, RW, and RW contains RELRO. At run time, after RELRO is write-protected, we'd have VMAs in the order of: R, RX,

Hi, I've tagged the LLVM 9.0.1-rc1 release. Testers can begin testing and upload binaries. I've also updated the test-release.sh script to pull from GitHub instead of SVN, if you run into any issues with the new script, let me know. -Tom

Yeah, it crashes indeed. I can reproduce the problem locally. Let me see what is going on. On Tue, Jul 16, 2019 at 9:00 PM Shi, Steven <steven.shi at intel.com> wrote: > In my previous test case, after add the `-fno-builtin` to clang then > build, the lld-link still has same crash as below: > > > > $ make > >

Hi Rui, We meet a problem when enable the execute in place (XIP, https://en.wikipedia.org/wiki/Execute_in_place) for uefi firmware with lld-link. We need to set the COFF executable file SectionAlignment through the lld-link /ALIGN option, but we find the SectionAlignment is hardcoded to 4096 which cause the /ALIGN option doesn't work at all. Below is the hardcode in lld: lld\COFF\Writer.h

Hi, I've just tagged the 9.0.1-final release. Testers can begin uploading binaries. -Tom