search for: linkages

...w linkage type? The idea behind the "linker" linkage types is that they are used by the linker and then discarded. I.e., the symbols won't show up in the final linked image. In that regard, all "linker" linkage types are inherently "private". The "linker" linkages are currently used only by Objective-C metadata, and only Darwin's linker has the facility to handle them. However, they aren't restricted to Objective-C metadata or Darwin. The "linker_private_weak" linkage has similar semantics to the "linker_private" linkage: it'...

...is consistent with the above behavior. 5 Linkage Change Summary Table The following table summarizes the linkage change that happen during ThinLTO backend compilations. Note that the only time the linkage changes in the original module is for the static promotion case (for Internal and Private linkages), where it changes to External as described in Section 4.3.1. In all other cases the linkage in the original module stays the same, and therefore is not noted in the table below. Note that there are no InternalLinkage, PrivateLinkage, AvailableExternallyLinkage, LinkOnce*Linkage, Weak*Linkage, App...

...w linkage type? The idea behind the "linker" linkage types is that they are used by the linker and then discarded. I.e., the symbols won't show up in the final linked image. In that regard, all "linker" linkage types are inherently "private". The "linker" linkages are currently used only by Objective-C metadata, and only Darwin's linker has the facility to handle them. Right. > However, they aren't restricted to Objective-C metadata or Darwin. I'd say that the semantics aren't darwin-specific, but it is very unlikely that any other targ...

Okay, I'm past the GEP "have to dereference pointer first" problem of my last post. I now have a linkage error (I get undefined symbol when I try to assemble the program). gcc -o test.o test.s says: > /tmp/cczhiFk7.o(.text+0x7): In function `a': > : undefined reference to `_index_' _index_ is defined like this: > %_index_ = external global long ;

+nick and rafael, who seem to a lot about linkage. I made the following claim on llmv-commits [1]: On 2014 Mar 3, at 15:01, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote: > Giving these functions internal linkage allows them to be dead-stripped. Is that even correct? This is the assumption I’ve been working under, but I’m not sure where I got it from. It seems like the

Sorry if this question is a repeat, I never got an answer the last time I asked :) How does appending linkage interact with dead global elimination? From what I understand, appending linkage arrays are stitched together by the linker. Dead global elimination usually happens after linking, so if any of those arrays are "live", then any globals that they point to will be live as well. My

...; even when the value is unreferenced, i.e. it may be referenced by another > module. This includes all linkage types except local (internal or private) > and linkonce. > > (Isn't available_externally also discardable?) > True. Here I was going with the definition of discardable linkages returned by GlobalValue::isDiscardableIfUnused, which only returns true for local and linkonce. > > For these values (both variables and functions), a reference may be > imported into another module without fear that its definition may be > eliminated in the original module. As a res...

Hi all, Below is a proposal for refining the way we communicate between the ThinLTO link step (the combined indexing step) and the backend processes that do the actual importing and other summary-based optimizations in a distributed backend process. Mehdi, let me know if this addresses your concerns. Peter, PTAL from the standpoint of any summary extensions needed for CFI and make sure they can

...seems to me that the basic breakdown here is: - Is this definition strong, ODR-weak, or semantically replaceable within the linkage unit? - Is this definition strong, ODR-weak, or semantically replaceable outside the linkage unit? When the definition uses the same rules for both, the existing linkages are fine: external, weak_odr / linkonce_odr, or weak, respectively. So let’s break down the cases by their declared visibility and see where it’s possible to use different rules inside and outside the linkage unit. Hidden definitions obviously never use different rules outside the linkage unit....

http://llvm.org/docs/LangRef.html#linkage-types says: Globals with “linkonce” linkage are merged with other globals of the same name when linkage occurs. This can be used to implement some forms of inline functions, templates, or other code which must be generated in each translation unit that uses it, but where the body may be overridden with a more definitive definition later. Unreferenced

On Tue, Oct 24, 2017 at 9:27 PM, Vedant Kumar <vsk at apple.com> wrote: > Unreferenced linkonce globals are allowed to be discarded. > > > Is __udivmodti4 referenced? > It's referenced by a different .o file, but nothing within the module. My confusion comes from the missing direct object in the sentence. Referenced by a function local to the module? Referenced by any

Append linkage is magical. It doesn't correspond to anything available in real object files (ELF/COFF/MachO). In those files sections are appended, but symbols are just resolved. That means that appending linkage can only be used with llvm special symbols that never hit a real .o. Long term I think we should delete it an replace with explicit use of section. But for now I would like to just

So, I was in the process of writing a custom LLVM pass (my first one, yay!) to handle the problem of measuring the length of an appending linkage array. The approach I was taking was pretty simple: Iterate through all of the module's global variables until I find one that is trying to calculate the end of an appending-linkage array, which looks like this: @_moduleListEnd = constant [1 x

On 13 May 2016 at 08:51, Renato Golin <renato.golin at linaro.org> wrote: > On 13 May 2016 at 13:43, Rafael Espíndola <llvm-dev at lists.llvm.org> wrote: >> That means that appending linkage can only be used with llvm special >> symbols that never hit a real .o. > > So they should have been resolved by emission time, or it's a back-end error. Not resolved,

On Thu, Dec 10, 2009 at 12:26 AM, Robin Sommer <robinsommer at web.de> wrote: > > On Sat, Dec 05, 2009 at 22:56 -0800, I wrote: > >> the LLVM documentation lists the 'appending' linkage for having the >> linker combine two arrays. I'm wondering though if it's then >> possible to get the size of the combined array, e.g., for iterating >> over

Hello, while improving and extending support for dllexport/import I have noticed that the current way these are implemented is problematic and I would like some input on how to proceed. Currently dllexport/dllimport is treated as linkage type. This conflicts with inlined functions because there is no linkage for the combination of both. On first though, combining both doesn't make sense, but

Hey all, Below is the proposed format for the dump of the ThinLTO module summary in the llvm-dis utility: > ../build/bin/llvm-dis t.o && cat t.o.ll ; ModuleID = '2.o' source_filename = "2.ll" target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" @X = constant i32 42, section "foo", align

Thanks Mehdi. My pass clones the functions within a module in order to have the original function and an exact copy of the same function but with a different name, i.e. sum() and sum_parallel(). After my pass I will run ThreadSanitizer instrumentation pass only on the new copy of the functions, i.e. only the “_parallel” functions will be instrumented by tsan. In some programs that I am

Hello. I'm posting this question here, because there seem to be no LLD-specific mailing list. Sorry in advance if this is wrong one. I compile two C source with following command: clang -flto -o %name.bc %name.c LLVM is augmented with my custom pass, which amongst other things create a global with appending linkage: @myvar = appending constant [1 x [1 x i8]*] ... I also have another pass

An enumeration for the kinds of linkage for global values. Hi, I'm currently writing a compiler that takes llvm-ir input. I'm a little confused by the following linkage flags: Enumerator: > > ExternalLinkage: Externally visible function > > AvailableExternallyLinkage: Available for inspection, not emission. > > LinkOnceAnyLinkage: Keep one copy of function when linking