[lld] r286937 - Avoid creating reference from nullptr.

[Vitaly Buka via llvm-commits]

Existing http://google.github.io/sanitizers/show_bots.html

On Tue, Nov 15, 2016 at 6:00 AM Rafael Espíndola <rafael.espindola at gmail.com>
wrote:

> This was found by an existing test with ubsan or should we add
> something to lld/test/ELF?
>
> Thanks,
> Rafael
>
>
> On 15 November 2016 at 02:32, Vitaly Buka via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Author: vitalybuka
> > Date: Tue Nov 15 01:32:51 2016
> > New Revision: 286937
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=286937&view=rev
> > Log:
> > Avoid creating reference from nullptr.
> >
> > Summary:
> > getFile() can return nullptr. This usually happens when Rels is empty so
> > the reference is never used. Still UBSAN complains.
> >
> > Reviewers: rafael
> >
> > Subscribers: llvm-commits
> >
> > Differential Revision: https://reviews.llvm.org/D26662
> >
> > Modified:
> >     lld/trunk/ELF/Relocations.cpp
> >
> > Modified: lld/trunk/ELF/Relocations.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Relocations.cpp?rev=286937&r1=286936&r2=286937&view=diff
> >
> ==============================================================================
> > --- lld/trunk/ELF/Relocations.cpp (original)
> > +++ lld/trunk/ELF/Relocations.cpp Tue Nov 15 01:32:51 2016
> > @@ -615,7 +615,7 @@ static void scanRelocs(InputSectionBase<
> >      Out<ELFT>::RelaDyn->addReloc(Reloc);
> >    };
> >
> > -  const elf::ObjectFile<ELFT> &File = *C.getFile();
> > +  const elf::ObjectFile<ELFT> *File = C.getFile();
> >    ArrayRef<uint8_t> SectionData = C.Data;
> >    const uint8_t *Buf = SectionData.begin();
> >
> > @@ -628,7 +628,7 @@ static void scanRelocs(InputSectionBase<
> >
> >    for (auto I = Rels.begin(), E = Rels.end(); I != E; ++I) {
> >      const RelTy &RI = *I;
> > -    SymbolBody &Body = File.getRelocTargetSym(RI);
> > +    SymbolBody &Body = File->getRelocTargetSym(RI);
> >      uint32_t Type = RI.getType(Config->Mips64EL);
> >
> >      if (Config->MipsN32Abi) {
> > @@ -645,7 +645,7 @@ static void scanRelocs(InputSectionBase<
> >
> >      RelExpr Expr = Target->getRelExpr(Type, Body);
> >      bool Preemptible = isPreemptible(Body, Type);
> > -    Expr = adjustExpr(File, Body, IsWrite, Expr, Type, Buf +
> RI.r_offset);
> > +    Expr = adjustExpr(*File, Body, IsWrite, Expr, Type, Buf +
> RI.r_offset);
> >      if (HasError)
> >        continue;
> >
> > @@ -673,7 +673,7 @@ static void scanRelocs(InputSectionBase<
> >          Expr == R_GOTREL || Expr == R_GOTREL_FROM_END || Expr ==
> R_PPC_TOC)
> >        In<ELFT>::Got->HasGotOffRel = true;
> >
> > -    uintX_t Addend = computeAddend(File, Buf, E, RI, Expr, Body);
> > +    uintX_t Addend = computeAddend(*File, Buf, E, RI, Expr, Body);
> >
> >      if (unsigned Processed =
> >              handleTlsRelocation<ELFT>(Type, Body, C, Offset, Addend,
> Expr)) {
> > @@ -796,14 +796,14 @@ template <class ELFT> void scanRelocatio
> >
> >  template <class ELFT, class RelTy>
> >  static void createThunks(InputSectionBase<ELFT> &C, ArrayRef<RelTy>
> Rels) {
> > -  const elf::ObjectFile<ELFT> &File = *C.getFile();
> > +  const elf::ObjectFile<ELFT> *File = C.getFile();
> >    for (const RelTy &Rel : Rels) {
> > -    SymbolBody &Body = File.getRelocTargetSym(Rel);
> > +    SymbolBody &Body = File->getRelocTargetSym(Rel);
> >      uint32_t Type = Rel.getType(Config->Mips64EL);
> >      RelExpr Expr = Target->getRelExpr(Type, Body);
> >      if (!isPreemptible(Body, Type) && needsPlt(Expr))
> >        Expr = fromPlt(Expr);
> > -    Expr = Target->getThunkExpr(Expr, Type, File, Body);
> > +    Expr = Target->getThunkExpr(Expr, Type, *File, Body);
> >      // Some targets might require creation of thunks for relocations.
> >      // Now we support only MIPS which requires LA25 thunk to call PIC
> >      // code from non-PIC one, and ARM which requires interworking.
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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