1 //===- ObjC.cpp -----------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "ObjC.h" 10 #include "InputFiles.h" 11 #include "InputSection.h" 12 #include "OutputSegment.h" 13 #include "Target.h" 14 15 #include "llvm/BinaryFormat/MachO.h" 16 #include "llvm/Bitcode/BitcodeReader.h" 17 18 using namespace llvm; 19 using namespace llvm::MachO; 20 using namespace lld; 21 using namespace lld::macho; 22 23 template <class LP> static bool objectHasObjCSection(MemoryBufferRef mb) { 24 using SectionHeader = typename LP::section; 25 26 auto *hdr = 27 reinterpret_cast<const typename LP::mach_header *>(mb.getBufferStart()); 28 if (hdr->magic != LP::magic) 29 return false; 30 31 if (const auto *c = 32 findCommand<typename LP::segment_command>(hdr, LP::segmentLCType)) { 33 auto sectionHeaders = ArrayRef<SectionHeader>{ 34 reinterpret_cast<const SectionHeader *>(c + 1), c->nsects}; 35 for (const SectionHeader &secHead : sectionHeaders) { 36 StringRef sectname(secHead.sectname, 37 strnlen(secHead.sectname, sizeof(secHead.sectname))); 38 StringRef segname(secHead.segname, 39 strnlen(secHead.segname, sizeof(secHead.segname))); 40 if ((segname == segment_names::data && 41 sectname == section_names::objcCatList) || 42 (segname == segment_names::text && 43 sectname == section_names::swift)) { 44 return true; 45 } 46 } 47 } 48 return false; 49 } 50 51 static bool objectHasObjCSection(MemoryBufferRef mb) { 52 if (target->wordSize == 8) 53 return ::objectHasObjCSection<LP64>(mb); 54 else 55 return ::objectHasObjCSection<ILP32>(mb); 56 } 57 58 bool macho::hasObjCSection(MemoryBufferRef mb) { 59 switch (identify_magic(mb.getBuffer())) { 60 case file_magic::macho_object: 61 return objectHasObjCSection(mb); 62 case file_magic::bitcode: 63 return check(isBitcodeContainingObjCCategory(mb)); 64 default: 65 return false; 66 } 67 } 68