Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. Yes, you should just stick with your post-processing pass or something like it. The design of linkonce_odr linkage is that such definitions will only be emitted when they are actually used. Even with this attribute, a translation unit that consists solely of:

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

tstellarAMD added a comment. Hi John, The problem we are trying to solve here is linking a LLVM bitcode program (OpenCL kernel in this specific case) with an LLVM bitcode library (OpenCL builtin library) and having the resulting LLVM bitcode module contain only the program code and the

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. You could also get this effect by somehow making the definitions linkonce_odr when they're linked in from the library. Or you could simply use the classic static-archive technique of putting each symbol in its own object file and linking against the whole thing as a

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. Does your linker not supported dead-code stripping? http://reviews.llvm.org/D18095 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl added a comment. Sorry my previous example may have caused some confusion. Previously I said I wanted to override function definitions. However the only reason we want to add this attribute is so that unused functions will be dropped by the linker. http://reviews.llvm.org/D18095

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. You still don't actually want linkonce_odr linkage. You don't want the weak definition to be inlined, so it can't be ODR, and you want to force it to be emitted in your library, so it can't be linkonce. You just want weak linkage. There's an existing attribute for

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl added a comment. If __attribute__((linkonce_odr_linkage)) is not a proper name for explicitly setting linkage, how about __attribute((linkage=linkonce_odr))? This can be extended to other linkages too. http://reviews.llvm.org/D18095 ___

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl updated the summary for this revision. yaxunl removed rL LLVM as the repository for this revision. yaxunl updated this revision to Diff 51297. yaxunl added a comment. Simplify description of this attribute in AttrDocs since it causes some confusion. http://reviews.llvm.org/D18095

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl added a comment. we can turn off inlining when we build lib_common.ll, then do optimization and inlining after linking with lib_common.ll and lib_opt.ll. Even if linkonce_odr allows inlining, it is still OK. Repository: rL LLVM http://reviews.llvm.org/D18095

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. Well, your overriding definitions will be strong definitions. The question is whether you want to allow inning of the weak definitions, i.e. the possibly-overridden ones, and there I would assume not. Repository: rL LLVM http://reviews.llvm.org/D18095

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl added a comment. Yes we want the overriding functions to be allowed to be inlined. Repository: rL LLVM http://reviews.llvm.org/D18095 ___ cfe-commits mailing list cfe-commits@lists.llvm.org

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. linkonce_odr would allow them to be dropped if unused by the library. In fact, we don't normally emit IR for functions that are linkonce and not used. Do you actually want code in lib_common to e.g. inline the common implementation instead of calling the optimized

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl added a comment. My last example is not proper. In real cases, the functions are overridden by functions with the same name and semantics but optimized for speed. Besides, we want unused library functions in lib_common.ll and lib_opt.ll to be dropped, weak attribute does not achieve

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. Your use case violates the "ODR" restriction on linkonce_odr. Do you maybe just want __attribute__((weak))? Repository: rL LLVM http://reviews.llvm.org/D18095 ___ cfe-commits mailing list cfe-commits@lists.llvm.org

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

On Mon, Mar 14, 2016 at 10:45 AM, Yaxun Liu via cfe-commits wrote: > yaxunl added a comment. > > Thanks for your comments. > > It works like this, e.g. > > $ cat prog.ll > declare i32 @foo() > > define void @use_foo() { > > %a = call i32 @foo() > ret void > > } > >

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

yaxunl added a comment. Thanks for your comments. It works like this, e.g. $ cat prog.ll declare i32 @foo() define void @use_foo() { %a = call i32 @foo() ret void } $ cat lib_common.ll define linkonce_odr i32 @foo() { ret i32 1; } $ cat lib_opt.ll define linkonce_odr i32 @foo() {

Re: [PATCH] D18095: Add __attribute__((linkonce_odr_linkage))

rjmccall added a comment. Okay, first off, linkonce_odr is not an acceptable term to be introducing as an attribute name. If we need this, we can find some way to describe it that isn't a random internal compiler term. More importantly, I don't understand how your problem is solved by