diff options
| -rw-r--r-- | lld/ELF/Writer.cpp | 96 |
1 files changed, 43 insertions, 53 deletions
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp index 834ff0b6072..708e29049fb 100644 --- a/lld/ELF/Writer.cpp +++ b/lld/ELF/Writer.cpp @@ -672,15 +672,51 @@ void Writer<ELFT>::scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) { continue; } - if (Expr == R_GOT && !isStaticLinkTimeConstant<ELFT>(Expr, Type, Body) && - Config->Shared) - AddDyn({Target->RelativeRel, C.OutSec, Offset, true, &Body, Addend}); - - // If a relocation needs PLT, we create a PLT and a GOT slot - // for the symbol. - if (needsPlt(Expr)) { + if (needsPlt(Expr) || Expr == R_THUNK || refersToGotEntry(Expr) || + !Body.isPreemptible()) { + // If the relocation points to something in the file, remember it so that + // we can apply it when writting the section. C.Relocations.push_back({Expr, Type, Offset, Addend, &Body}); + // If the output being produced is position independent, the final value + // is still not known. In that case we still need some help from the + // dynamic linker. We can however do better than just copying the incoming + // relocation. We can process some of it and and just ask the dynamic + // linker to add the load address. + if (!isStaticLinkTimeConstant<ELFT>(Expr, Type, Body)) + AddDyn({Target->RelativeRel, C.OutSec, Offset, true, &Body, Addend}); + } else { + // We don't know anything about the finaly symbol. Just ask the dynamic + // linker to handle the relocation for us. + AddDyn({Target->getDynRel(Type), C.OutSec, Offset, false, &Body, Addend}); + // MIPS ABI turns using of GOT and dynamic relocations inside out. + // While regular ABI uses dynamic relocations to fill up GOT entries + // MIPS ABI requires dynamic linker to fills up GOT entries using + // specially sorted dynamic symbol table. This affects even dynamic + // relocations against symbols which do not require GOT entries + // creation explicitly, i.e. do not have any GOT-relocations. So if + // a preemptible symbol has a dynamic relocation we anyway have + // to create a GOT entry for it. + // If a non-preemptible symbol has a dynamic relocation against it, + // dynamic linker takes it st_value, adds offset and writes down + // result of the dynamic relocation. In case of preemptible symbol + // dynamic linker performs symbol resolution, writes the symbol value + // to the GOT entry and reads the GOT entry when it needs to perform + // a dynamic relocation. + // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf p.4-19 + if (Config->EMachine == EM_MIPS && !Body.isInGot()) + Out<ELFT>::Got->addEntry(Body); + continue; + } + + if (Expr == R_THUNK) + continue; + + // At this point we are done with the relocated position. Some relocations + // also require us to create a got or plt entry. + + // If a relocation needs PLT, we create a PLT and a GOT slot for the symbol. + if (needsPlt(Expr)) { if (Body.isInPlt()) continue; Out<ELFT>::Plt->addEntry(Body); @@ -706,14 +742,7 @@ void Writer<ELFT>::scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) { continue; } - if (Expr == R_THUNK) { - C.Relocations.push_back({Expr, Type, Offset, Addend, &Body}); - continue; - } - - // If a relocation needs GOT, we create a GOT slot for the symbol. if (refersToGotEntry(Expr)) { - C.Relocations.push_back({Expr, Type, Offset, Addend, &Body}); if (Body.isInGot()) continue; Out<ELFT>::Got->addEntry(Body); @@ -739,45 +768,6 @@ void Writer<ELFT>::scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) { } continue; } - - if (Body.isPreemptible()) { - // We don't know anything about the finaly symbol. Just ask the dynamic - // linker to handle the relocation for us. - AddDyn({Target->getDynRel(Type), C.OutSec, Offset, false, &Body, Addend}); - // MIPS ABI turns using of GOT and dynamic relocations inside out. - // While regular ABI uses dynamic relocations to fill up GOT entries - // MIPS ABI requires dynamic linker to fills up GOT entries using - // specially sorted dynamic symbol table. This affects even dynamic - // relocations against symbols which do not require GOT entries - // creation explicitly, i.e. do not have any GOT-relocations. So if - // a preemptible symbol has a dynamic relocation we anyway have - // to create a GOT entry for it. - // If a non-preemptible symbol has a dynamic relocation against it, - // dynamic linker takes it st_value, adds offset and writes down - // result of the dynamic relocation. In case of preemptible symbol - // dynamic linker performs symbol resolution, writes the symbol value - // to the GOT entry and reads the GOT entry when it needs to perform - // a dynamic relocation. - // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf p.4-19 - if (Config->EMachine == EM_MIPS && !Body.isInGot()) - Out<ELFT>::Got->addEntry(Body); - continue; - } - - // We know that this is the final symbol. If the program being produced - // is position independent, the final value is still not known. - // If the relocation depends on the symbol value (not the size or distances - // in the output), we still need some help from the dynamic linker. - // We can however do better than just copying the incoming relocation. We - // can process some of it and and just ask the dynamic linker to add the - // load address. - if (!Config->Pic || isStaticLinkTimeConstant<ELFT>(Expr, Type, Body)) { - C.Relocations.push_back({Expr, Type, Offset, Addend, &Body}); - continue; - } - - AddDyn({Target->RelativeRel, C.OutSec, Offset, true, &Body, Addend}); - C.Relocations.push_back({Expr, Type, Offset, Addend, &Body}); } // Scan relocations for necessary thunks. |
