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[dsymutil] Skip mach-o paired relocations 

Noticed while working on scattered relocations.
I do not think these relocs can actually happen in the debug_info section,
but if they happen the code would mishandle them. Explicitely skip them
and warn if we encounter one.

llvm-svn: 259341
This commit is contained in:
Frederic Riss 2016-02-01 04:43:14 +00:00
parent efb41741f2
commit 1d53658eae
1 changed files with 34 additions and 0 deletions
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34
llvm/tools/dsymutil/DwarfLinker.cpp
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@ -1875,6 +1875,26 @@ void DwarfLinker::endDebugObject() {
DIEAlloc.Reset();
}
static bool isMachOPairedReloc(uint64_t RelocType, uint64_t Arch) {
switch (Arch) {
case Triple::x86:
return RelocType == MachO::GENERIC_RELOC_SECTDIFF ||
RelocType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF;
case Triple::x86_64:
return RelocType == MachO::X86_64_RELOC_SUBTRACTOR;
case Triple::arm:
case Triple::thumb:
return RelocType == MachO::ARM_RELOC_SECTDIFF ||
RelocType == MachO::ARM_RELOC_LOCAL_SECTDIFF ||
RelocType == MachO::ARM_RELOC_HALF ||
RelocType == MachO::ARM_RELOC_HALF_SECTDIFF;
case Triple::aarch64:
return RelocType == MachO::ARM64_RELOC_SUBTRACTOR;
default:
return false;
}
}
/// \brief Iterate over the relocations of the given \p Section and
/// store the ones that correspond to debug map entries into the
/// ValidRelocs array.
@ -1885,10 +1905,24 @@ findValidRelocsMachO(const object::SectionRef &Section,
StringRef Contents;
Section.getContents(Contents);
DataExtractor Data(Contents, Obj.isLittleEndian(), 0);
bool SkipNext = false;
for (const object::RelocationRef &Reloc : Section.relocations()) {
if (SkipNext) {
SkipNext = false;
continue;
}
object::DataRefImpl RelocDataRef = Reloc.getRawDataRefImpl();
MachO::any_relocation_info MachOReloc = Obj.getRelocation(RelocDataRef);
if (isMachOPairedReloc(Obj.getAnyRelocationType(MachOReloc),
Obj.getArch())) {
SkipNext = true;
Linker.reportWarning(" unsupported relocation in debug_info section.");
continue;
}
unsigned RelocSize = 1 << Obj.getAnyRelocationLength(MachOReloc);
uint64_t Offset64 = Reloc.getOffset();
if ((RelocSize != 4 && RelocSize != 8)) {