similar to: [LLVMdev] [PATCH] Minor typos corrected in docs

Hello, I’m not sure if this is the right place to ask beginner questions. If not, please direct me to the appropriate place. I’m writing my first llvm program and I’m trying to call an intrinsic, but failing. So far this is what I have: declare ccc i32 @llvm.x86.bmi.pdep.32(i32, i32) @.str2 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1 declare i32 @printf(i8*, ...)

Hi, I recently found that thinLTO doesn't deal with globals that has linkonce_odr and unnamed_addr (for macho at least) because it prohibits the autohide optimization during link time. In LLVM, we tagged a global linkonce_odr and unnamed_addr to indicate to the linker can hide them from symbol table if they were picked (aka, linkonce_odr_auto_hide linkage). It is very commonly used for some

2018-02-08 9:33 GMT-08:00 Steven Wu <stevenwu at apple.com>: > > > On Feb 7, 2018, at 4:03 PM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > > 2018-02-07 12:45 GMT-08:00 Steven Wu <stevenwu at apple.com>: > >> >> >> On Feb 7, 2018, at 12:36 PM, Mehdi AMINI <joker.eph at gmail.com> wrote: >> >> > But it is

There should be no semantic difference between linkonce_odr and weak_odr, except that weak_odr is non-discardable. Why doesn't the autohide optimization work just as well on weak_odr + unnamed_addr as linkonce_odr + unnamed_addr? On Tue, Feb 6, 2018 at 5:35 PM, Steven Wu via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi, > > I recently found that thinLTO doesn't deal

Hi all, First post to the list, I hope you can help or guide me on this task. I am involved in a project that requires to re-link extracted and edited IR code Thus I want to know if these tools can be used in this way? clang++-4.0 code03.cpp -emit-llvm -S -o code03.ll llvm-extract-4.0 code03.ll -func main -S -o extracted_main.ll llvm-link-4.0 code03.ll -only-needed -override extracted_main.ll

> On Feb 8, 2018, at 10:28 AM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > > 2018-02-08 9:33 GMT-08:00 Steven Wu <stevenwu at apple.com <mailto:stevenwu at apple.com>>: > > >> On Feb 7, 2018, at 4:03 PM, Mehdi AMINI <joker.eph at gmail.com <mailto:joker.eph at gmail.com>> wrote: >> >> >> >> 2018-02-07

2018-02-08 10:44 GMT-08:00 Steven Wu <stevenwu at apple.com>: > > > On Feb 8, 2018, at 10:28 AM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > > 2018-02-08 9:33 GMT-08:00 Steven Wu <stevenwu at apple.com>: > >> >> >> On Feb 7, 2018, at 4:03 PM, Mehdi AMINI <joker.eph at gmail.com> wrote: >> >> >> >>

Steven Wu <stevenwu at apple.com> writes: > Add Rafael here. Because he basically ask me the same question in my commit. > > I wonder why clang choose to do unnamed_addr instead of just do visibility hidden. If linkonce_odr + unnamed_addr is just hidden, is the only difference linkonce_odr + unnamed_addr not in the symbol table? A local symbol being in the symbol table is mostly

SGTM. I would do as 2 separate patches, the local per-module case, then the case that requires linker/global analysis. Thanks, Teresa On Fri, Feb 9, 2018 at 9:20 AM, Steven Wu via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Are we agreeing on this is what we should do? If so, I will prepare a > patch. > > Steven > > > On Feb 8, 2018, at 11:07 AM, Mehdi AMINI

2018-02-07 12:45 GMT-08:00 Steven Wu <stevenwu at apple.com>: > > > On Feb 7, 2018, at 12:36 PM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > But it is interesting in general because according to the definition > for local_unnamed_addr, the symbol has to be linkonce_odr to be auto hide > as well. ThinLTO promotion can break that as well. > > What do

I wonder whether we could change the frontend to always give hidden visibility to globals which are linkonce_odr unnamed_addr. That way, the mechanism would just work in ELF as well and would not require LTO. Peter On Fri, Feb 9, 2018 at 10:46 AM, Steven Wu via llvm-dev < llvm-dev at lists.llvm.org> wrote: > The one that doesn’t require global analysis is commit in r324757. > >

I agree with Teresa, we should probably do #2 to preserve behavior for now. On Wed, Feb 7, 2018 at 9:34 AM, Teresa Johnson via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi Steven, > > I'd prefer not to inhibit importing. I am also concerned about putting > these symbols in the llvm.compiler_used (I don't recall earlier discussion > around this, but it seems

That is a good question and I don't know. The optimization is defined include/llvm/Analysis/ObjectUtils.h. If I enable that for weak_odr + unnamed_addr, no tests are failing so I guess it is a safe optimization? :) It is probably because the autohide optimization is targeted at c++ templates and inline functions and we know they have linkonce_odr linkage, which suggests whoever uses this

Hi John, What targer are you trying to compile this for? I imagine this is just a case of using an X86 intrinsic on a non-X86 back end. Or is this an intrinsic you added and didn't provide a selection pattern for? In any case, this intrinsic makes it into the selection DAG and the instruction selector tries to select a sequence of instructions for it. However, it fails to find a pattern that

Hi Steven, I'd prefer not to inhibit importing. I am also concerned about putting these symbols in the llvm.compiler_used (I don't recall earlier discussion around this, but it seems like it could have effects on optimization as you mention). What are the downsides of #2 (adding visibility hidden)? We already do this when promoting internal linkage to external due to importing. I'm

Something I haven't seen mentioned: why are we dropping the unnamed_addr? Can't we preserve it with the weak symbol? Would it be OK to add auto-hide in this case (maybe it would already happen)? Can we use the new local_unnamed_addr that was added (by pcc or Rafael I don't remember)? I think this attribute matches exactly the `auto-hide` semantic. Wasn't the idea that this could be

On Thu, Feb 8, 2018 at 10:44 AM, Steven Wu via llvm-dev < llvm-dev at lists.llvm.org> wrote: > > > On Feb 8, 2018, at 10:28 AM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > > 2018-02-08 9:33 GMT-08:00 Steven Wu <stevenwu at apple.com>: > >> >> >> On Feb 7, 2018, at 4:03 PM, Mehdi AMINI <joker.eph at gmail.com> wrote: >>

Are we agreeing on this is what we should do? If so, I will prepare a patch. Steven > On Feb 8, 2018, at 11:07 AM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > > 2018-02-08 10:44 GMT-08:00 Steven Wu <stevenwu at apple.com <mailto:stevenwu at apple.com>>: > > >> On Feb 8, 2018, at 10:28 AM, Mehdi AMINI <joker.eph at gmail.com

> On Feb 7, 2018, at 4:03 PM, Mehdi AMINI <joker.eph at gmail.com> wrote: > > > > 2018-02-07 12:45 GMT-08:00 Steven Wu <stevenwu at apple.com <mailto:stevenwu at apple.com>>: > > >> On Feb 7, 2018, at 12:36 PM, Mehdi AMINI <joker.eph at gmail.com <mailto:joker.eph at gmail.com>> wrote: >> >> > But it is interesting in

The one that doesn’t require global analysis is commit in r324757. The global analysis will require adding a field into GlobalSummary. Let me do some research. The implementation should not be hard but I don’t want to break bitcode compatibility if that applies to the summary. Steven > On Feb 9, 2018, at 9:33 AM, Teresa Johnson <tejohnson at google.com> wrote: > > SGTM. I would