[lld] r286937 - Avoid creating reference from nullptr.

[Rafael Espíndola via llvm-commits]

Awesome.

Thanks,
Rafael


On 15 November 2016 at 15:03, Vitaly Buka <vitalybuka at google.com> wrote:
> Sorry, wrong link.
> This one
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/624/steps/check-lld%20ubsan/logs/stdio
>
> On Tue, Nov 15, 2016 at 12:03 PM Vitaly Buka <vitalybuka at google.com> wrote:
>>
>> 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.
>>> >
>>> >
>>> > _______________________________________________
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>>> > llvm-commits at lists.llvm.org
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