similar to: intra vs inter module LTO

> Message: 2 > Date: Mon, 31 Dec 2018 18:55:13 +0100 > From: "A. Ilchinger via llvm-dev" <llvm-dev at lists.llvm.org> > To: llvm-dev at lists.llvm.org > Subject: [llvm-dev] intra vs inter module LTO > Message-ID: <0MdFwl-1gvHrS3utf-00ISyE at mail.gmx.com> > Content-Type: text/plain; charset=US-ASCII > > I'd like to know if LTO also works in the

I'd like to write an inter-modular analysis pass. My understanding is that this should take the form of an LTO pass. However, I have been unable to find any resources on the mechanics of writing and running a custom LTO pass. Does anyone have any pointers? Thanks, Steve -------------- next part -------------- An HTML attachment was scrubbed... URL:

RFC: (Thin)LTO with Linker Scripts At the last US LLVM Developers' Meeting, we presented [1] a proposal for linker script support in (Thin)LTO. In this RFC, I would like to describe the proposal in more detail and invite the community's feedback, so we can build consensus on the upstream implementation. The end goal of this effort is to extend the benefits of (Thin)LTO, including

> On May 17, 2016, at 11:21 AM, Umesh Kalappa <umesh.kalappa0 at gmail.com> wrote: > > Steven, > > As mehdi stated , the optimisation level is specific to linker and it > enables Inter-Pro opts passes ,please refer function To be very clear: the -O option may trigger *linker* optimizations as well, independently of LTO. -- Mehdi > >

Hi Mehdi, After deeper debug, I found my firmware LTO wrong code issue is related to X64 code model (-mcmodel=large) is always overridden as small (-mcmodel=small) if LTO build. And I don't know how to correctly specific the large code model for my X64 firmware LTO build. Appreciate if you could let me know it. You know, parts of my Uefi firmware (BIOS) have to been loaded to run in high

> On May 17, 2016, at 1:33 AM, Shi, Steven via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hello, > Let me ask a LTO simple question again. For the llvm LTO example in the link:http://llvm.org/docs/LinkTimeOptimization.html <http://llvm.org/docs/LinkTimeOptimization.html>, I use below build commands to generate three different optimization level binary: -O0, -O1, -O2.

Hi Mehdi, GCC LTO seems support large code model in my side as below, if the code model is linker specific, does the GCC LTO use a special linker which is different from the one in GNU Binutils? I'm a bit surprised if both OS X ld64 and gold plugin do not support large code model in LTO. Since modern system widely use the 64bit, the code need to run in high address (larger than 2 GB) is a

We don't use cl::opt in gold, instead we parse the -plugin-opts that gold passes the plugin (see process_plugin_option). Cheers, Rafael On 30 May 2016 at 02:13, Mehdi Amini <mehdi.amini at apple.com> wrote: > > On May 29, 2016, at 5:44 PM, Shi, Steven <steven.shi at intel.com> wrote: > > (And I doubt the GNU linker supports LTO with LLVM). > [Steven]: I’ve pushed

Hi, > On May 29, 2016, at 7:36 AM, Shi, Steven <steven.shi at intel.com> wrote: > > Hi Mehdi, > After deeper debug, I found my firmware LTO wrong code issue is related to X64 code model (-mcmodel=large) is always overridden as small (-mcmodel=small) if LTO build. And I don't know how to correctly specific the large code model for my X64 firmware LTO build. Appreciate if

(And I doubt the GNU linker supports LTO with LLVM). [Steven]: I’ve pushed GNU Binutils ld to support LLVM gold plugin, see detail in this bug https://sourceware.org/bugzilla/show_bug.cgi?id=20070. The new GNU ld linker works well with LLVM/Clang LTO when build IA32 code in my side. And from the ld owner input in the bug comments, the current X64 LLVM LTO issue is in llvm LTO plugin. The fact

Hello Tobias, Thanks very much for the RFC, I think that this will be useful in persuading embedded developers to use LTO in their projects. I think the overall approach for communication between the linker and code generator sounds reasonable. I've got some questions/comments based on some experience with Arm's proprietary linker, which supports LTO but has a different linker script

> On May 29, 2016, at 5:10 PM, Shi, Steven <steven.shi at intel.com> wrote: > > Hi Mehdi, > GCC LTO seems support large code model in my side as below, if the code model is linker specific, does the GCC LTO use a special linker which is different from the one in GNU Binutils? I don't know anything about GCC. (And I doubt the GNU linker supports LTO with LLVM). > I’m a

Hi, The specification does not give any indication on when recording intra-frame. Obviously the first frame is an intra frame but after what is the strategy used in Theora ? I think an intra frame is recorded whenever consecutive frames become too different ? Is there any criterion ? What's happen in case of periodic changes (*blinking *lights for exemple) ? Thanks J.F.

Hi Mehdi, Should I apply your attached patch on my llvm3.8 source firstly? Or should I use the latest llvm SVN trunk instead? Steven Shi Intel\SSG\STO\UEFI Firmware Tel: +86 021-61166522 iNet: 821-6522 From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] Sent: Monday, May 30, 2016 2:13 PM To: Shi, Steven <steven.shi at intel.com> Cc: Umesh Kalappa <umesh.kalappa0 at

Hi, I have tried to build libjpeg-turbo <https://github.com/libjpeg-turbo/libjpeg-turbo> with LTO in LLVM, using both clangbut get many errors in lld that look like the following: ld: error: undefined symbol: jpeg_std_error >>> referenced by jcstest.c:76 >>> lto.tmp:(main) ld: error: undefined symbol: jpeg_CreateCompress >>> referenced by

Hi, I'm using clang frontend. I'm interested in some particular hot loop in my code and I emit a report from vectorizer optimizations passes. I receive nice output if passing -Rpass* flags as long as I'm building without LTO? But with -flto it just prints nothing. Is there a way to emit opt reports when using LTO? For now I can only approximate about whether my the loop will be

I am wondering how the following issue was handled for libLTO? We have a working patch to implement the FSF gcc LTO on darwin which now passes all of the liblto testsuite but are seeing linker issues with larger programs like aermod... as -arch x86_64 -force_cpusubtype_ALL -o aermod.o aermod.s /usr/bin/ld -dynamic -arch x86_64 -macosx_version_min 10.6.3 -weak_reference_mismatches

Hello, I'm enabling clang LTO to improve code size of Uefi standard (http://www.uefi.org/) firmware (https://github.com/tianocore/edk2), which is mostly C code. My project is in https://github.com/shijunjing/edk2 branch llvm : https://github.com/shijunjing/edk2/tree/llvm. I find my most firmware modules work well after enable LTO, but some X64 modules will not run (e.g. hang with CPU

Hi all, I wanted to start a thread to discuss ways to control the optimization level when using LTO. We have found that there are use cases for the LTO mechanism beyond whole-program optimization, in which full optimization is not always needed or desired. We started that discussion over in http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150316/266560.html and I thought I'd

Hi Umesh, Thank you for the suggestion. I can use the "Brute force method " to narrow down the LTO wrong instructions here and there, but I still don't know why these wrong instructions are generated, and how to let Clang LTO don't generate those wrong instructions. I suspect the wrong code is caused by some LTO wrong optimization pass, so I hope to disable all optimizations in