//===- Target.h -------------------------------------------------*- C++ -*-===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #ifndef LLD_MACHO_TARGET_H #define LLD_MACHO_TARGET_H #include "MachOStructs.h" #include "Relocations.h" #include "llvm/ADT/BitmaskEnum.h" #include "llvm/BinaryFormat/MachO.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/MemoryBuffer.h" #include <cstddef> #include <cstdint> #include "mach-o/compact_unwind_encoding.h" namespace lld::macho { LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE(); class Symbol; class Defined; class DylibSymbol; class InputSection; class ObjFile; static_assert(static_cast<uint32_t>(UNWIND_X86_64_MODE_MASK) == static_cast<uint32_t>(UNWIND_X86_MODE_MASK) && static_cast<uint32_t>(UNWIND_ARM64_MODE_MASK) == static_cast<uint32_t>(UNWIND_X86_64_MODE_MASK)); // Since the mode masks have the same value on all targets, define // a common one for convenience. constexpr uint32_t UNWIND_MODE_MASK = UNWIND_X86_64_MODE_MASK; class TargetInfo { public: template <class LP> TargetInfo(LP) { // Having these values available in TargetInfo allows us to access them // without having to resort to templates. magic = LP::magic; pageZeroSize = LP::pageZeroSize; headerSize = sizeof(typename LP::mach_header); wordSize = LP::wordSize; p2WordSize = llvm::CTLog2<LP::wordSize>(); } virtual ~TargetInfo() = default; // Validate the relocation structure and get its addend. virtual int64_t getEmbeddedAddend(llvm::MemoryBufferRef, uint64_t offset, const llvm::MachO::relocation_info) const = 0; virtual void relocateOne(uint8_t *loc, const Reloc &, uint64_t va, uint64_t relocVA) const = 0; // Write code for lazy binding. See the comments on StubsSection for more // details. virtual void writeStub(uint8_t *buf, const Symbol &, uint64_t pointerVA) const = 0; virtual void writeStubHelperHeader(uint8_t *buf) const = 0; virtual void writeStubHelperEntry(uint8_t *buf, const Symbol &, uint64_t entryAddr) const = 0; virtual void writeObjCMsgSendStub(uint8_t *buf, Symbol *sym, uint64_t stubsAddr, uint64_t &stubOffset, uint64_t selrefsVA, uint64_t selectorIndex, Symbol *objcMsgSend) const = 0; // Symbols may be referenced via either the GOT or the stubs section, // depending on the relocation type. prepareSymbolRelocation() will set up the // GOT/stubs entries, and resolveSymbolVA() will return the addresses of those // entries. resolveSymbolVA() may also relax the target instructions to save // on a level of address indirection. virtual void relaxGotLoad(uint8_t *loc, uint8_t type) const = 0; virtual uint64_t getPageSize() const = 0; virtual void populateThunk(InputSection *thunk, Symbol *funcSym) { llvm_unreachable("target does not use thunks"); } const RelocAttrs &getRelocAttrs(uint8_t type) const { assert(type < relocAttrs.size() && "invalid relocation type"); if (type >= relocAttrs.size()) return invalidRelocAttrs; return relocAttrs[type]; } bool hasAttr(uint8_t type, RelocAttrBits bit) const { return getRelocAttrs(type).hasAttr(bit); } bool usesThunks() const { return thunkSize > 0; } // For now, handleDtraceReloc only implements -no_dtrace_dof, and ensures // that the linking would not fail even when there are user-provided dtrace // symbols. However, unlike ld64, lld currently does not emit __dof sections. virtual void handleDtraceReloc(const Symbol *sym, const Reloc &r, uint8_t *loc) const { llvm_unreachable("Unsupported architecture for dtrace symbols"); } virtual void applyOptimizationHints(uint8_t *, const ObjFile &) const {}; uint32_t magic; llvm::MachO::CPUType cpuType; uint32_t cpuSubtype; uint64_t pageZeroSize; size_t headerSize; size_t stubSize; size_t stubHelperHeaderSize; size_t stubHelperEntrySize; size_t objcStubsFastSize; size_t objcStubsSmallSize; size_t objcStubsFastAlignment; size_t objcStubsSmallAlignment; uint8_t p2WordSize; size_t wordSize; size_t thunkSize = 0; uint64_t forwardBranchRange = 0; uint64_t backwardBranchRange = 0; uint32_t modeDwarfEncoding; uint8_t subtractorRelocType; uint8_t unsignedRelocType; llvm::ArrayRef<RelocAttrs> relocAttrs; // We contrive this value as sufficiently far from any valid address that it // will always be out-of-range for any architecture. UINT64_MAX is not a // good choice because it is (a) only 1 away from wrapping to 0, and (b) the // tombstone value for DenseMap<> and caused weird assertions for me. static constexpr uint64_t outOfRangeVA = 0xfull << 60; }; TargetInfo *createX86_64TargetInfo(); TargetInfo *createARM64TargetInfo(); TargetInfo *createARM64_32TargetInfo(); struct LP64 { using mach_header = llvm::MachO::mach_header_64; using nlist = structs::nlist_64; using segment_command = llvm::MachO::segment_command_64; using section = llvm::MachO::section_64; using encryption_info_command = llvm::MachO::encryption_info_command_64; static constexpr uint32_t magic = llvm::MachO::MH_MAGIC_64; static constexpr uint32_t segmentLCType = llvm::MachO::LC_SEGMENT_64; static constexpr uint32_t encryptionInfoLCType = llvm::MachO::LC_ENCRYPTION_INFO_64; static constexpr uint64_t pageZeroSize = 1ull << 32; static constexpr size_t wordSize = 8; }; struct ILP32 { using mach_header = llvm::MachO::mach_header; using nlist = structs::nlist; using segment_command = llvm::MachO::segment_command; using section = llvm::MachO::section; using encryption_info_command = llvm::MachO::encryption_info_command; static constexpr uint32_t magic = llvm::MachO::MH_MAGIC; static constexpr uint32_t segmentLCType = llvm::MachO::LC_SEGMENT; static constexpr uint32_t encryptionInfoLCType = llvm::MachO::LC_ENCRYPTION_INFO; static constexpr uint64_t pageZeroSize = 1ull << 12; static constexpr size_t wordSize = 4; }; extern TargetInfo *target; } // namespace lld::macho #endif