search for: isdiscardableifunused

On Fri, May 15, 2015 at 9:18 AM, David Blaikie <dblaikie at gmail.com> wrote: > >> >> - Marking of imported functions (for use in ThinLTO-specific symbol >> >> linking and global DCE, for example). >> > >> > Marking how? Do you mean giving them internal linkage, or something >> > else? >> >> Mentioned just after this: either

...e. See the > next para for an example where I am unsure about doing this... > > Looking back through my GlobalDCE changes, it looks like one of the > places I had changed (where we mark defined globals in runOnModule) > already has a guard for !hasAvailableExternallyLinkage and > !isDiscardableIfUnused, so my additional guard against marking > imported functions is unnecessary. But the other place I had to change > was in GlobalIsNeeded where it walks through the function and > recursively marks any referenced global as needed. Here there was no > guard against marking a global that i...

...t;> >> >>> >> Looking back through my GlobalDCE changes, it looks like one of the >>> >> places I had changed (where we mark defined globals in runOnModule) >>> >> already has a guard for !hasAvailableExternallyLinkage and >>> >> !isDiscardableIfUnused, so my additional guard against marking >>> >> imported functions is unnecessary. But the other place I had to change >>> >> was in GlobalIsNeeded where it walks through the function and >>> >> recursively marks any referenced global as needed. Here ther...

...gt;> the >> >> >>> >> places I had changed (where we mark defined globals in >> >> >>> >> runOnModule) >> >> >>> >> already has a guard for !hasAvailableExternallyLinkage and >> >> >>> >> !isDiscardableIfUnused, so my additional guard against marking >> >> >>> >> imported functions is unnecessary. But the other place I had to >> >> >>> >> change >> >> >>> >> was in GlobalIsNeeded where it walks through the function and >&g...

...; >> Looking back through my GlobalDCE changes, it looks like one of the >> >>> >> places I had changed (where we mark defined globals in runOnModule) >> >>> >> already has a guard for !hasAvailableExternallyLinkage and >> >>> >> !isDiscardableIfUnused, so my additional guard against marking >> >>> >> imported functions is unnecessary. But the other place I had to >> >>> >> change >> >>> >> was in GlobalIsNeeded where it walks through the function and >> >>> >> re...

Hi all, I'd like to propose that LLVM IR have a mechanism to describe sections in a more explicit way than we can today. Currently, we provide an attribute called "section" on GlobalVariables and Functions. This attribute will choose which section the Value will end up in. However, it does not describe the attributes of the section. Without a way of describing the section, we try

...>>>>>>>>> places I had changed (where we mark defined globals in >>>>>>>>>>> runOnModule) >>>>>>>>>>> already has a guard for !hasAvailableExternallyLinkage and >>>>>>>>>>> !isDiscardableIfUnused, so my additional guard against marking >>>>>>>>>>> imported functions is unnecessary. But the other place I had to >>>>>>>>>>> change >>>>>>>>>>> was in GlobalIsNeeded where it walks through the func...

...ced, 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 result, when the definitions of > these non-dis...

As mentioned in the Updated ThinLTO RFC ( http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-May/086211.html), I am sending the symbol linkage and renaming required by ThinLTO as a separate RFC. It is included below. I've also attached the doc in pdf form, since the formatting (especially for the table at the end) may not come through in the copied text below well. Thanks! Teresa ThinLTO