2946cd7010
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
323 lines
13 KiB
C++
323 lines
13 KiB
C++
//===- lib/FileFormat/MachO/ArchHandler.h ---------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLD_READER_WRITER_MACHO_ARCH_HANDLER_H
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#define LLD_READER_WRITER_MACHO_ARCH_HANDLER_H
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#include "Atoms.h"
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#include "File.h"
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#include "MachONormalizedFile.h"
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#include "lld/Common/LLVM.h"
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#include "lld/Core/Error.h"
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#include "lld/Core/Reference.h"
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#include "lld/Core/Simple.h"
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#include "lld/ReaderWriter/MachOLinkingContext.h"
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#include "llvm/ADT/Triple.h"
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namespace lld {
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namespace mach_o {
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///
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/// The ArchHandler class handles all architecture specific aspects of
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/// mach-o linking.
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///
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class ArchHandler {
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public:
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virtual ~ArchHandler();
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/// There is no public interface to subclasses of ArchHandler, so this
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/// is the only way to instantiate an ArchHandler.
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static std::unique_ptr<ArchHandler> create(MachOLinkingContext::Arch arch);
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/// Get (arch specific) kind strings used by Registry.
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virtual const Registry::KindStrings *kindStrings() = 0;
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/// Convert mach-o Arch to Reference::KindArch.
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virtual Reference::KindArch kindArch() = 0;
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/// Used by StubPass to update References to shared library functions
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/// to be references to a stub.
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virtual bool isCallSite(const Reference &) = 0;
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/// Used by GOTPass to locate GOT References
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virtual bool isGOTAccess(const Reference &, bool &canBypassGOT) {
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return false;
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}
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/// Used by TLVPass to locate TLV References.
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virtual bool isTLVAccess(const Reference &) const { return false; }
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/// Used by the TLVPass to update TLV References.
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virtual void updateReferenceToTLV(const Reference *) {}
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/// Used by ShimPass to insert shims in branches that switch mode.
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virtual bool isNonCallBranch(const Reference &) = 0;
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/// Used by GOTPass to update GOT References
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virtual void updateReferenceToGOT(const Reference *, bool targetIsNowGOT) {}
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/// Does this architecture make use of __unwind_info sections for exception
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/// handling? If so, it will need a separate pass to create them.
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virtual bool needsCompactUnwind() = 0;
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/// Returns the kind of reference to use to synthesize a 32-bit image-offset
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/// value, used in the __unwind_info section.
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virtual Reference::KindValue imageOffsetKind() = 0;
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/// Returns the kind of reference to use to synthesize a 32-bit image-offset
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/// indirect value. Used for personality functions in the __unwind_info
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/// section.
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virtual Reference::KindValue imageOffsetKindIndirect() = 0;
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/// Architecture specific compact unwind type that signals __eh_frame should
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/// actually be used.
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virtual uint32_t dwarfCompactUnwindType() = 0;
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/// Reference from an __eh_frame CIE atom to its personality function it's
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/// describing. Usually pointer-sized and PC-relative, but differs in whether
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/// it needs to be in relocatable objects.
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virtual Reference::KindValue unwindRefToPersonalityFunctionKind() = 0;
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/// Reference from an __eh_frame FDE to the CIE it's based on.
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virtual Reference::KindValue unwindRefToCIEKind() = 0;
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/// Reference from an __eh_frame FDE atom to the function it's
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/// describing. Usually pointer-sized and PC-relative, but differs in whether
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/// it needs to be in relocatable objects.
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virtual Reference::KindValue unwindRefToFunctionKind() = 0;
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/// Reference from an __unwind_info entry of dwarfCompactUnwindType to the
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/// required __eh_frame entry. On current architectures, the low 24 bits
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/// represent the offset of the function's FDE entry from the start of
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/// __eh_frame.
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virtual Reference::KindValue unwindRefToEhFrameKind() = 0;
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/// Returns a pointer sized reference kind. On 64-bit targets this will
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/// likely be something like pointer64, and pointer32 on 32-bit targets.
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virtual Reference::KindValue pointerKind() = 0;
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virtual const Atom *fdeTargetFunction(const DefinedAtom *fde);
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/// Used by normalizedFromAtoms() to know where to generated rebasing and
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/// binding info in final executables.
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virtual bool isPointer(const Reference &) = 0;
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/// Used by normalizedFromAtoms() to know where to generated lazy binding
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/// info in final executables.
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virtual bool isLazyPointer(const Reference &);
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/// Reference from an __stub_helper entry to the required offset of the
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/// lazy bind commands.
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virtual Reference::KindValue lazyImmediateLocationKind() = 0;
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/// Returns true if the specified relocation is paired to the next relocation.
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virtual bool isPairedReloc(const normalized::Relocation &) = 0;
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/// Prototype for a helper function. Given a sectionIndex and address,
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/// finds the atom and offset with that atom of that address.
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typedef std::function<llvm::Error (uint32_t sectionIndex, uint64_t addr,
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const lld::Atom **, Reference::Addend *)>
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FindAtomBySectionAndAddress;
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/// Prototype for a helper function. Given a symbolIndex, finds the atom
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/// representing that symbol.
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typedef std::function<llvm::Error (uint32_t symbolIndex,
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const lld::Atom **)> FindAtomBySymbolIndex;
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/// Analyzes a relocation from a .o file and returns the info
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/// (kind, target, addend) needed to instantiate a Reference.
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/// Two helper functions are passed as parameters to find the target atom
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/// given a symbol index or address.
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virtual llvm::Error
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getReferenceInfo(const normalized::Relocation &reloc,
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const DefinedAtom *inAtom,
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uint32_t offsetInAtom,
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uint64_t fixupAddress, bool isBigEndian,
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FindAtomBySectionAndAddress atomFromAddress,
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FindAtomBySymbolIndex atomFromSymbolIndex,
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Reference::KindValue *kind,
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const lld::Atom **target,
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Reference::Addend *addend) = 0;
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/// Analyzes a pair of relocations from a .o file and returns the info
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/// (kind, target, addend) needed to instantiate a Reference.
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/// Two helper functions are passed as parameters to find the target atom
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/// given a symbol index or address.
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virtual llvm::Error
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getPairReferenceInfo(const normalized::Relocation &reloc1,
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const normalized::Relocation &reloc2,
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const DefinedAtom *inAtom,
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uint32_t offsetInAtom,
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uint64_t fixupAddress, bool isBig, bool scatterable,
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FindAtomBySectionAndAddress atomFromAddress,
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FindAtomBySymbolIndex atomFromSymbolIndex,
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Reference::KindValue *kind,
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const lld::Atom **target,
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Reference::Addend *addend) = 0;
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/// Prototype for a helper function. Given an atom, finds the symbol table
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/// index for it in the output file.
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typedef std::function<uint32_t (const Atom &atom)> FindSymbolIndexForAtom;
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/// Prototype for a helper function. Given an atom, finds the index
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/// of the section that will contain the atom.
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typedef std::function<uint32_t (const Atom &atom)> FindSectionIndexForAtom;
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/// Prototype for a helper function. Given an atom, finds the address
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/// assigned to it in the output file.
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typedef std::function<uint64_t (const Atom &atom)> FindAddressForAtom;
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/// Some architectures require local symbols on anonymous atoms.
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virtual bool needsLocalSymbolInRelocatableFile(const DefinedAtom *atom) {
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return false;
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}
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/// Copy raw content then apply all fixup References on an Atom.
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virtual void generateAtomContent(const DefinedAtom &atom, bool relocatable,
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FindAddressForAtom findAddress,
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FindAddressForAtom findSectionAddress,
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uint64_t imageBaseAddress,
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llvm::MutableArrayRef<uint8_t> atomContentBuffer) = 0;
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/// Used in -r mode to convert a Reference to a mach-o relocation.
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virtual void appendSectionRelocations(const DefinedAtom &atom,
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uint64_t atomSectionOffset,
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const Reference &ref,
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FindSymbolIndexForAtom,
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FindSectionIndexForAtom,
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FindAddressForAtom,
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normalized::Relocations&) = 0;
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/// Add arch-specific References.
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virtual void addAdditionalReferences(MachODefinedAtom &atom) { }
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// Add Reference for data-in-code marker.
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virtual void addDataInCodeReference(MachODefinedAtom &atom, uint32_t atomOff,
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uint16_t length, uint16_t kind) { }
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/// Returns true if the specificed Reference value marks the start or end
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/// of a data-in-code range in an atom.
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virtual bool isDataInCodeTransition(Reference::KindValue refKind) {
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return false;
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}
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/// Returns the Reference value for a Reference that marks that start of
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/// a data-in-code range.
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virtual Reference::KindValue dataInCodeTransitionStart(
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const MachODefinedAtom &atom) {
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return 0;
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}
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/// Returns the Reference value for a Reference that marks that end of
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/// a data-in-code range.
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virtual Reference::KindValue dataInCodeTransitionEnd(
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const MachODefinedAtom &atom) {
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return 0;
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}
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/// Only relevant for 32-bit arm archs.
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virtual bool isThumbFunction(const DefinedAtom &atom) { return false; }
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/// Only relevant for 32-bit arm archs.
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virtual const DefinedAtom *createShim(MachOFile &file, bool thumbToArm,
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const DefinedAtom &) {
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llvm_unreachable("shims only support on arm");
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}
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/// Does a given unwind-cfi atom represent a CIE (as opposed to an FDE).
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static bool isDwarfCIE(bool isBig, const DefinedAtom *atom);
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struct ReferenceInfo {
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Reference::KindArch arch;
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uint16_t kind;
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uint32_t offset;
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int32_t addend;
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};
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struct OptionalRefInfo {
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bool used;
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uint16_t kind;
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uint32_t offset;
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int32_t addend;
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};
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/// Table of architecture specific information for creating stubs.
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struct StubInfo {
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const char* binderSymbolName;
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ReferenceInfo lazyPointerReferenceToHelper;
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ReferenceInfo lazyPointerReferenceToFinal;
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ReferenceInfo nonLazyPointerReferenceToBinder;
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uint8_t codeAlignment;
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uint32_t stubSize;
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uint8_t stubBytes[16];
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ReferenceInfo stubReferenceToLP;
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OptionalRefInfo optStubReferenceToLP;
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uint32_t stubHelperSize;
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uint8_t stubHelperBytes[16];
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ReferenceInfo stubHelperReferenceToImm;
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ReferenceInfo stubHelperReferenceToHelperCommon;
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DefinedAtom::ContentType stubHelperImageCacheContentType;
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uint32_t stubHelperCommonSize;
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uint8_t stubHelperCommonAlignment;
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uint8_t stubHelperCommonBytes[36];
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ReferenceInfo stubHelperCommonReferenceToCache;
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OptionalRefInfo optStubHelperCommonReferenceToCache;
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ReferenceInfo stubHelperCommonReferenceToBinder;
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OptionalRefInfo optStubHelperCommonReferenceToBinder;
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};
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virtual const StubInfo &stubInfo() = 0;
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protected:
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ArchHandler();
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static std::unique_ptr<mach_o::ArchHandler> create_x86_64();
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static std::unique_ptr<mach_o::ArchHandler> create_x86();
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static std::unique_ptr<mach_o::ArchHandler> create_arm();
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static std::unique_ptr<mach_o::ArchHandler> create_arm64();
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// Handy way to pack mach-o r_type and other bit fields into one 16-bit value.
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typedef uint16_t RelocPattern;
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enum {
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rScattered = 0x8000,
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rPcRel = 0x4000,
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rExtern = 0x2000,
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rLength1 = 0x0000,
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rLength2 = 0x0100,
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rLength4 = 0x0200,
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rLength8 = 0x0300,
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rLenArmLo = rLength1,
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rLenArmHi = rLength2,
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rLenThmbLo = rLength4,
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rLenThmbHi = rLength8
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};
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/// Extract RelocPattern from normalized mach-o relocation.
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static RelocPattern relocPattern(const normalized::Relocation &reloc);
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/// Create normalized Relocation initialized from pattern.
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static normalized::Relocation relocFromPattern(RelocPattern pattern);
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/// One liner to add a relocation.
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static void appendReloc(normalized::Relocations &relocs, uint32_t offset,
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uint32_t symbol, uint32_t value,
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RelocPattern pattern);
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static int16_t readS16(const uint8_t *addr, bool isBig);
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static int32_t readS32(const uint8_t *addr, bool isBig);
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static uint32_t readU32(const uint8_t *addr, bool isBig);
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static int64_t readS64(const uint8_t *addr, bool isBig);
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};
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} // namespace mach_o
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} // namespace lld
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#endif // LLD_READER_WRITER_MACHO_ARCH_HANDLER_H
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