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 Section = 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 = 34 ArrayRef<Section>{reinterpret_cast<const Section *>(c + 1), c->nsects}; 35 for (const Section &sec : sectionHeaders) { 36 StringRef sectname(sec.sectname, 37 strnlen(sec.sectname, sizeof(sec.sectname))); 38 StringRef segname(sec.segname, strnlen(sec.segname, sizeof(sec.segname))); 39 if ((segname == segment_names::data && 40 sectname == section_names::objcCatList) || 41 (segname == segment_names::text && 42 sectname == section_names::swift)) { 43 return true; 44 } 45 } 46 } 47 return false; 48 } 49 50 static bool objectHasObjCSection(MemoryBufferRef mb) { 51 if (target->wordSize == 8) 52 return ::objectHasObjCSection<LP64>(mb); 53 else 54 return ::objectHasObjCSection<ILP32>(mb); 55 } 56 57 bool macho::hasObjCSection(MemoryBufferRef mb) { 58 switch (identify_magic(mb.getBuffer())) { 59 case file_magic::macho_object: 60 return objectHasObjCSection(mb); 61 case file_magic::bitcode: 62 return check(isBitcodeContainingObjCCategory(mb)); 63 default: 64 return false; 65 } 66 } 67