1//===-- RuntimeDyldMachO.h - Run-time dynamic linker for MC-JIT ---*- C++ -*-=//
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// MachO support for MC-JIT runtime dynamic linker.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDMACHO_H
14#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDMACHO_H
15
16#include "RuntimeDyldImpl.h"
17#include "llvm/Object/MachO.h"
18#include "llvm/Support/Format.h"
19
20namespace llvm {
21class RuntimeDyldMachO : public RuntimeDyldImpl {
22protected:
23 struct SectionOffsetPair {
24 unsigned SectionID;
25 uint64_t Offset;
26 };
27
28 struct EHFrameRelatedSections {
29 EHFrameRelatedSections()
30 : EHFrameSID(RTDYLD_INVALID_SECTION_ID),
31 TextSID(RTDYLD_INVALID_SECTION_ID),
32 ExceptTabSID(RTDYLD_INVALID_SECTION_ID) {}
33
34 EHFrameRelatedSections(SID EH, SID T, SID Ex)
35 : EHFrameSID(EH), TextSID(T), ExceptTabSID(Ex) {}
36 SID EHFrameSID;
37 SID TextSID;
38 SID ExceptTabSID;
39 };
40
41 // When a module is loaded we save the SectionID of the EH frame section
42 // in a table until we receive a request to register all unregistered
43 // EH frame sections with the memory manager.
44 SmallVector<EHFrameRelatedSections, 2> UnregisteredEHFrameSections;
45
46 RuntimeDyldMachO(RuntimeDyld::MemoryManager &MemMgr,
47 JITSymbolResolver &Resolver)
48 : RuntimeDyldImpl(MemMgr, Resolver) {}
49
50 /// This convenience method uses memcpy to extract a contiguous addend (the
51 /// addend size and offset are taken from the corresponding fields of the RE).
52 int64_t memcpyAddend(const RelocationEntry &RE) const;
53
54 /// Given a relocation_iterator for a non-scattered relocation, construct a
55 /// RelocationEntry and fill in the common fields. The 'Addend' field is *not*
56 /// filled in, since immediate encodings are highly target/opcode specific.
57 /// For targets/opcodes with simple, contiguous immediates (e.g. X86) the
58 /// memcpyAddend method can be used to read the immediate.
59 RelocationEntry getRelocationEntry(unsigned SectionID,
60 const ObjectFile &BaseTObj,
61 const relocation_iterator &RI) const {
62 const MachOObjectFile &Obj =
63 static_cast<const MachOObjectFile &>(BaseTObj);
64 MachO::any_relocation_info RelInfo =
65 Obj.getRelocation(Rel: RI->getRawDataRefImpl());
66
67 bool IsPCRel = Obj.getAnyRelocationPCRel(RE: RelInfo);
68 unsigned Size = Obj.getAnyRelocationLength(RE: RelInfo);
69 uint64_t Offset = RI->getOffset();
70 MachO::RelocationInfoType RelType =
71 static_cast<MachO::RelocationInfoType>(Obj.getAnyRelocationType(RE: RelInfo));
72
73 return RelocationEntry(SectionID, Offset, RelType, 0, IsPCRel, Size);
74 }
75
76 /// Process a scattered vanilla relocation.
77 Expected<relocation_iterator>
78 processScatteredVANILLA(unsigned SectionID, relocation_iterator RelI,
79 const ObjectFile &BaseObjT,
80 RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
81 bool TargetIsLocalThumbFunc = false);
82
83 /// Construct a RelocationValueRef representing the relocation target.
84 /// For Symbols in known sections, this will return a RelocationValueRef
85 /// representing a (SectionID, Offset) pair.
86 /// For Symbols whose section is not known, this will return a
87 /// (SymbolName, Offset) pair, where the Offset is taken from the instruction
88 /// immediate (held in RE.Addend).
89 /// In both cases the Addend field is *NOT* fixed up to be PC-relative. That
90 /// should be done by the caller where appropriate by calling makePCRel on
91 /// the RelocationValueRef.
92 Expected<RelocationValueRef>
93 getRelocationValueRef(const ObjectFile &BaseTObj,
94 const relocation_iterator &RI,
95 const RelocationEntry &RE,
96 ObjSectionToIDMap &ObjSectionToID);
97
98 /// Make the RelocationValueRef addend PC-relative.
99 void makeValueAddendPCRel(RelocationValueRef &Value,
100 const relocation_iterator &RI,
101 unsigned OffsetToNextPC);
102
103 /// Dump information about the relocation entry (RE) and resolved value.
104 void dumpRelocationToResolve(const RelocationEntry &RE, uint64_t Value) const;
105
106 // Return a section iterator for the section containing the given address.
107 static section_iterator getSectionByAddress(const MachOObjectFile &Obj,
108 uint64_t Addr);
109
110
111 // Populate __pointers section.
112 Error populateIndirectSymbolPointersSection(const MachOObjectFile &Obj,
113 const SectionRef &PTSection,
114 unsigned PTSectionID);
115
116public:
117
118 /// Create a RuntimeDyldMachO instance for the given target architecture.
119 static std::unique_ptr<RuntimeDyldMachO>
120 create(Triple::ArchType Arch,
121 RuntimeDyld::MemoryManager &MemMgr,
122 JITSymbolResolver &Resolver);
123
124 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
125 loadObject(const object::ObjectFile &O) override;
126
127 SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
128
129 bool isCompatibleFile(const object::ObjectFile &Obj) const override;
130};
131
132/// RuntimeDyldMachOTarget - Templated base class for generic MachO linker
133/// algorithms and data structures.
134///
135/// Concrete, target specific sub-classes can be accessed via the impl()
136/// methods. (i.e. the RuntimeDyldMachO hierarchy uses the Curiously
137/// Recurring Template Idiom). Concrete subclasses for each target
138/// can be found in ./Targets.
139template <typename Impl>
140class RuntimeDyldMachOCRTPBase : public RuntimeDyldMachO {
141private:
142 Impl &impl() { return static_cast<Impl &>(*this); }
143 const Impl &impl() const { return static_cast<const Impl &>(*this); }
144
145 unsigned char *processFDE(uint8_t *P, int64_t DeltaForText,
146 int64_t DeltaForEH);
147
148public:
149 RuntimeDyldMachOCRTPBase(RuntimeDyld::MemoryManager &MemMgr,
150 JITSymbolResolver &Resolver)
151 : RuntimeDyldMachO(MemMgr, Resolver) {}
152
153 Error finalizeLoad(const ObjectFile &Obj,
154 ObjSectionToIDMap &SectionMap) override;
155 void registerEHFrames() override;
156};
157
158} // end namespace llvm
159
160#endif // LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDMACHO_H
161