search for: finalizesect

...ller and callee. This could mean assigning section addresses multiple times. 2.) The alterations to the core data structures to permit more than one Thunk per symbol and the logic to select the "right" Thunk for each relocation. The design I'd like to aim at moves thunk creation into finalizeSections() at a point where the sizes and addresses of all the SyntheticSections are known. This would mean that the final address of each caller and callee could be used, and after thunk creation there would be no further content changes. This would mean: - All code that runs prior to thunk creation ma...

Hi, Does lld support linker relaxation that may shrink code size? As far as I see lld seems to assume that the content of input sections to be fixed other than patching up relocations, but I believe some targets may benefit the extra optimization opportunity with relaxation. Specifically, I'm currently working on adding support for RISC-V in lld, and RISC-V heavily relies on linker relaxation

...dresses multiple times. >> 2.) The alterations to the core data structures to permit more than >> one Thunk per symbol and the logic to select the "right" Thunk for >> each relocation. >> >> The design I'd like to aim at moves thunk creation into >> finalizeSections() at a point where the sizes and addresses of all the >> SyntheticSections are known. This would mean that the final address of >> each caller and callee could be used, and after thunk creation there >> would be no further content changes. This would mean: >> - All code...

...make a > suggestion. > > I'm assuming that if you are doing some kind of range based relaxation > you'll need something like range extension thunks (I'm working on > these right now) this means you'll probably have to do your > calculations on what you can relax in finalizeSections() at a similar > point to createThunks(), or perhaps the mechanisms would need to be > merged as I think they'll need to converge on a point when no more > relaxations are possible and no more thunks can be added. > > Writing out the relaxed sections will be interesting as yo...

...C && !isAbsoluteValue(Sym)) Expr = Target->adjustRelaxExpr(Type, RelocatedAddr, Expr); diff --git a/ELF/Writer.cpp b/ELF/Writer.cpp index 90462ecc7..418133ebd 100644 --- a/ELF/Writer.cpp +++ b/ELF/Writer.cpp @@ -1570,8 +1570,11 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() { applySynthetic({InX::EhFrame}, [](SyntheticSection *SS) { SS->finalizeContents(); }); - for (Symbol *S : Symtab->getSymbols()) + for (Symbol *S : Symtab->getSymbols()) { S->IsPreemptible |= computeIsPreemptible(*S); + if (S->isGnuIFunc() &...

...t;find(s)); The issue can be demonstrated by the following call tree: LinkerDriver::link markLive ... resolveReloc // Defined::section is nullptr for `d` because the assignment d=foo hasn't been evaluated yet. writeResult Writer<ELFT>::run Writer<ELFT>::finalizeSections LinkerScript::processSymbolAssignments // Symbol section+offset are evaluated here. It seems that github issues may be a good place to record the problem. I just created https://github.com/llvm/llvm-project/issues/52 I wanted to mark it low priority, but there is no such labe...

...;>> I'm assuming that if you are doing some kind of range based relaxation >>> you'll need something like range extension thunks (I'm working on >>> these right now) this means you'll probably have to do your >>> calculations on what you can relax in finalizeSections() at a similar >>> point to createThunks(), or perhaps the mechanisms would need to be >>> merged as I think they'll need to converge on a point when no more >>> relaxations are possible and no more thunks can be added. >>> >>> Writing out the re...

...h have a branch instruction that has a limited range - On ARM and AArch64 the static linker is expected to insert range extension thunks when some classes of branch instruction are out of range Where are we now with LLD and thunks - We have moved the createThunks() function as late as it can be in finalizeSections(), most importantly after all the content has been added to the image. - We only call createThunks() once and we don't calculate addresses before createThunks(). - If an OutputSection is described by a LinkerScript then any thunks created in it are put at the end of the OutputSection. This...

On Wed, 4 Dec 2019 at 07:05, Fāng-ruì Sòng <maskray at google.com> wrote: > > On Tue, Dec 3, 2019 at 7:02 PM Shoaib Meenai via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > > > LLD treats any symbol referenced from a linker script as a GC root, which makes sense. Unfortunately, it also processes --defsym as a linker script fragment internally, so all target