+
+ relocation_iterator
+ processHALFSECTDIFFRelocation(unsigned SectionID, relocation_iterator RelI,
+ ObjectImage &Obj,
+ ObjSectionToIDMap &ObjSectionToID) {
+ const MachOObjectFile *MachO =
+ static_cast<const MachOObjectFile *>(Obj.getObjectFile());
+ MachO::any_relocation_info RE =
+ MachO->getRelocation(RelI->getRawDataRefImpl());
+
+
+ // For a half-diff relocation the length bits actually record whether this
+ // is a movw/movt, and whether this is arm or thumb.
+ // Bit 0 indicates movw (b0 == 0) or movt (b0 == 1).
+ // Bit 1 indicates arm (b1 == 0) or thumb (b1 == 1).
+ unsigned HalfDiffKindBits = MachO->getAnyRelocationLength(RE);
+ if (HalfDiffKindBits & 0x2)
+ llvm_unreachable("Thumb not yet supported.");
+
+ SectionEntry &Section = Sections[SectionID];
+ uint32_t RelocType = MachO->getAnyRelocationType(RE);
+ bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
+ uint64_t Offset;
+ RelI->getOffset(Offset);
+ uint8_t *LocalAddress = Section.Address + Offset;
+ int64_t Immediate = 0;
+ memcpy(&Immediate, LocalAddress, 4); // Copy the whole instruction out.
+ Immediate = ((Immediate >> 4) & 0xf000) | (Immediate & 0xfff);
+
+ ++RelI;
+ MachO::any_relocation_info RE2 =
+ MachO->getRelocation(RelI->getRawDataRefImpl());
+ uint32_t AddrA = MachO->getScatteredRelocationValue(RE);
+ section_iterator SAI = getSectionByAddress(*MachO, AddrA);
+ assert(SAI != MachO->section_end() && "Can't find section for address A");
+ uint64_t SectionABase;
+ SAI->getAddress(SectionABase);
+ uint64_t SectionAOffset = AddrA - SectionABase;
+ SectionRef SectionA = *SAI;
+ bool IsCode;
+ SectionA.isText(IsCode);
+ uint32_t SectionAID =
+ findOrEmitSection(Obj, SectionA, IsCode, ObjSectionToID);
+
+ uint32_t AddrB = MachO->getScatteredRelocationValue(RE2);
+ section_iterator SBI = getSectionByAddress(*MachO, AddrB);
+ assert(SBI != MachO->section_end() && "Can't find section for address B");
+ uint64_t SectionBBase;
+ SBI->getAddress(SectionBBase);
+ uint64_t SectionBOffset = AddrB - SectionBBase;
+ SectionRef SectionB = *SBI;
+ uint32_t SectionBID =
+ findOrEmitSection(Obj, SectionB, IsCode, ObjSectionToID);
+
+ uint32_t OtherHalf = MachO->getAnyRelocationAddress(RE2) & 0xffff;
+ unsigned Shift = (HalfDiffKindBits & 0x1) ? 16 : 0;
+ uint32_t FullImmVal = (Immediate << Shift) | (OtherHalf << (16 - Shift));
+ int64_t Addend = FullImmVal - (AddrA - AddrB);
+
+ // addend = Encoded - Expected
+ // = Encoded - (AddrA - AddrB)
+
+ DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA << ", AddrB: " << AddrB
+ << ", Addend: " << Addend << ", SectionA ID: " << SectionAID
+ << ", SectionAOffset: " << SectionAOffset
+ << ", SectionB ID: " << SectionBID
+ << ", SectionBOffset: " << SectionBOffset << "\n");
+ RelocationEntry R(SectionID, Offset, RelocType, Addend, SectionAID,
+ SectionAOffset, SectionBID, SectionBOffset, IsPCRel,
+ HalfDiffKindBits);
+
+ addRelocationForSection(R, SectionAID);
+ addRelocationForSection(R, SectionBID);
+
+ return ++RelI;
+ }
+