1 //===-- RuntimeDyldMachO.h - Run-time dynamic linker for MC-JIT ---*- C++ -*-=//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // MachO support for MC-JIT runtime dynamic linker.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_RUNTIME_DYLD_MACHO_H
15 #define LLVM_RUNTIME_DYLD_MACHO_H
17 #include "ObjectImageCommon.h"
18 #include "RuntimeDyldImpl.h"
19 #include "llvm/Object/MachO.h"
20 #include "llvm/Support/Format.h"
22 #define DEBUG_TYPE "dyld"
25 using namespace llvm::object;
28 class RuntimeDyldMachO : public RuntimeDyldImpl {
30 struct SectionOffsetPair {
35 struct EHFrameRelatedSections {
36 EHFrameRelatedSections()
37 : EHFrameSID(RTDYLD_INVALID_SECTION_ID),
38 TextSID(RTDYLD_INVALID_SECTION_ID),
39 ExceptTabSID(RTDYLD_INVALID_SECTION_ID) {}
41 EHFrameRelatedSections(SID EH, SID T, SID Ex)
42 : EHFrameSID(EH), TextSID(T), ExceptTabSID(Ex) {}
48 // When a module is loaded we save the SectionID of the EH frame section
49 // in a table until we receive a request to register all unregistered
50 // EH frame sections with the memory manager.
51 SmallVector<EHFrameRelatedSections, 2> UnregisteredEHFrameSections;
53 RuntimeDyldMachO(RTDyldMemoryManager *mm) : RuntimeDyldImpl(mm) {}
55 /// Extract the addend encoded in the instruction.
56 int64_t decodeAddend(uint8_t *LocalAddress, unsigned NumBytes,
57 MachO::RelocationInfoType RelType) const;
59 /// Construct a RelocationValueRef representing the relocation target.
60 /// For Symbols in known sections, this will return a RelocationValueRef
61 /// representing a (SectionID, Offset) pair.
62 /// For Symbols whose section is not known, this will return a
63 /// (SymbolName, Offset) pair, where the Offset is taken from the instruction
64 /// immediate (held in RE.Addend).
65 /// In both cases the Addend field is *NOT* fixed up to be PC-relative. That
66 /// should be done by the caller where appropriate by calling makePCRel on
67 /// the RelocationValueRef.
68 RelocationValueRef getRelocationValueRef(ObjectImage &ObjImg,
69 const relocation_iterator &RI,
70 const RelocationEntry &RE,
71 ObjSectionToIDMap &ObjSectionToID,
72 const SymbolTableMap &Symbols);
74 /// Make the RelocationValueRef addend PC-relative.
75 void makeValueAddendPCRel(RelocationValueRef &Value, ObjectImage &ObjImg,
76 const relocation_iterator &RI);
78 /// Dump information about the relocation entry (RE) and resolved value.
79 void dumpRelocationToResolve(const RelocationEntry &RE, uint64_t Value) const;
82 /// Create an ObjectImage from the given ObjectBuffer.
83 static ObjectImage *createObjectImage(ObjectBuffer *InputBuffer) {
84 return new ObjectImageCommon(InputBuffer);
87 /// Create an ObjectImage from the given ObjectFile.
89 createObjectImageFromFile(std::unique_ptr<object::ObjectFile> InputObject) {
90 return new ObjectImageCommon(std::move(InputObject));
93 /// Create a RuntimeDyldMachO instance for the given target architecture.
94 static std::unique_ptr<RuntimeDyldMachO> create(Triple::ArchType Arch,
95 RTDyldMemoryManager *mm);
97 /// Write the least significant 'Size' bytes in 'Value' out at the address
98 /// pointed to by Addr. Check for overflow.
99 bool writeBytesUnaligned(uint8_t *Addr, uint64_t Value, unsigned Size);
101 SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
103 bool isCompatibleFormat(const ObjectBuffer *Buffer) const override;
104 bool isCompatibleFile(const object::ObjectFile *Obj) const override;
105 void registerEHFrames() override;
108 /// RuntimeDyldMachOTarget - Templated base class for generic MachO linker
109 /// algorithms and data structures.
111 /// Concrete, target specific sub-classes can be accessed via the impl()
112 /// methods. (i.e. the RuntimeDyldMachO hierarchy uses the Curiously
113 /// Recurring Template Idiom). Concrete subclasses for each target
114 /// can be found in ./Targets.
115 template <typename Impl>
116 class RuntimeDyldMachOCRTPBase : public RuntimeDyldMachO {
118 Impl &impl() { return static_cast<Impl &>(*this); }
119 const Impl &impl() const { return static_cast<const Impl &>(*this); }
123 /// Parse the given relocation, which must be a non-scattered, and
124 /// return a RelocationEntry representing the information. The 'Addend' field
125 /// will contain the unmodified instruction immediate.
126 RelocationEntry getBasicRelocationEntry(unsigned SectionID,
128 const relocation_iterator &RI) const {
129 const MachOObjectFile &Obj =
130 static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
131 MachO::any_relocation_info RelInfo =
132 Obj.getRelocation(RI->getRawDataRefImpl());
134 const SectionEntry &Section = Sections[SectionID];
135 bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
136 unsigned Size = Obj.getAnyRelocationLength(RelInfo);
138 RI->getOffset(Offset);
139 uint8_t *LocalAddress = Section.Address + Offset;
140 unsigned NumBytes = 1 << Size;
141 MachO::RelocationInfoType RelType =
142 static_cast<MachO::RelocationInfoType>(Obj.getAnyRelocationType(RelInfo));
143 int64_t Addend = impl().decodeAddend(LocalAddress, NumBytes, RelType);
145 return RelocationEntry(SectionID, Offset, RelType, Addend, IsPCRel, Size);
149 RuntimeDyldMachOCRTPBase(RTDyldMemoryManager *mm) : RuntimeDyldMachO(mm) {}
151 void finalizeLoad(ObjectImage &ObjImg, ObjSectionToIDMap &SectionMap) {
152 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
153 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
154 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
155 ObjSectionToIDMap::iterator i, e;
157 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
158 const SectionRef &Section = i->first;
160 Section.getName(Name);
161 if (Name == "__eh_frame")
162 EHFrameSID = i->second;
163 else if (Name == "__text")
165 else if (Name == "__gcc_except_tab")
166 ExceptTabSID = i->second;
168 impl().finalizeSection(ObjImg, i->second, Section);
170 UnregisteredEHFrameSections.push_back(
171 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
175 } // end namespace llvm