Commit d0c4277d authored by Fangrui Song's avatar Fangrui Song
Browse files

[MC][ARM] Don't create multiple .ARM.exidx associated to one .text 

Fixed an issue exposed by D74006.

In clang cc1as, MCContext::UseNamesOnTempLabels is true.
When parsing a .fnstart directive, FnStart gets redefined to a temporary symbol of a different name (.Ltmp0, .Ltmp1, ...).
MCContext::getELFSection() called by SwitchToEHSection() will create a different .ARM.exidx each time.

llvm-mc uses `Ctx.setUseNamesOnTempLabels(false);` and FnStart is unnamed.
MCContext::getELFSection() called by SwitchToEHSection() will reuse the same .ARM.exidx .

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D75095
parent 6fb70c87

llvm/lib/MC/MCContext.cpp

+1 −0
Original line number Diff line number Diff line
@@ -405,6 +405,7 @@ MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type, 
  StringRef Group = "";

  if (GroupSym)

    Group = GroupSym->getName();

  assert(!(LinkedToSym && LinkedToSym->getName().empty()));

  // Do the lookup, if we have a hit, return it.

  auto IterBool = ELFUniquingMap.insert(std::make_pair(

      ELFSectionKey{Section.str(), Group,

llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

+1 −1
Original line number Diff line number Diff line
@@ -1201,7 +1201,7 @@ inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix, 
    Flags |= ELF::SHF_GROUP;

  MCSectionELF *EHSection = getContext().getELFSection(

      EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),

      static_cast<const MCSymbolELF *>(&Fn));

      static_cast<const MCSymbolELF *>(FnSection.getBeginSymbol()));



  assert(EHSection && "Failed to get the required EH section");