xref: /freebsd/contrib/llvm-project/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldMachOX86_64.h (revision bdd1243df58e60e85101c09001d9812a789b6bc4) 
1 //===-- RuntimeDyldMachOX86_64.h ---- MachO/X86_64 specific code. -*- 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 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOX86_64_H
10 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOX86_64_H
11 
12 #include "../RuntimeDyldMachO.h"
13 
14 #define DEBUG_TYPE "dyld"
15 
16 namespace llvm {
17 
18 class RuntimeDyldMachOX86_64
19     : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOX86_64> {
20 public:
21 
22   typedef uint64_t TargetPtrT;
23 
RuntimeDyldMachOX86_64(RuntimeDyld::MemoryManager & MM,JITSymbolResolver & Resolver)24   RuntimeDyldMachOX86_64(RuntimeDyld::MemoryManager &MM,
25                          JITSymbolResolver &Resolver)
26       : RuntimeDyldMachOCRTPBase(MM, Resolver) {}
27 
getMaxStubSize()28   unsigned getMaxStubSize() const override { return 8; }
29 
getStubAlignment()30   Align getStubAlignment() override { return Align(8); }
31 
32   Expected<relocation_iterator>
processRelocationRef(unsigned SectionID,relocation_iterator RelI,const ObjectFile & BaseObjT,ObjSectionToIDMap & ObjSectionToID,StubMap & Stubs)33   processRelocationRef(unsigned SectionID, relocation_iterator RelI,
34                        const ObjectFile &BaseObjT,
35                        ObjSectionToIDMap &ObjSectionToID,
36                        StubMap &Stubs) override {
37     const MachOObjectFile &Obj =
38       static_cast<const MachOObjectFile &>(BaseObjT);
39     MachO::any_relocation_info RelInfo =
40         Obj.getRelocation(RelI->getRawDataRefImpl());
41     uint32_t RelType = Obj.getAnyRelocationType(RelInfo);
42 
43     if (RelType == MachO::X86_64_RELOC_SUBTRACTOR)
44       return processSubtractRelocation(SectionID, RelI, Obj, ObjSectionToID);
45 
46     assert(!Obj.isRelocationScattered(RelInfo) &&
47            "Scattered relocations not supported on X86_64");
48 
49     RelocationEntry RE(getRelocationEntry(SectionID, Obj, RelI));
50     RE.Addend = memcpyAddend(RE);
51     RelocationValueRef Value;
52     if (auto ValueOrErr = getRelocationValueRef(Obj, RelI, RE, ObjSectionToID))
53       Value = *ValueOrErr;
54     else
55       return ValueOrErr.takeError();
56 
57     bool IsExtern = Obj.getPlainRelocationExternal(RelInfo);
58     if (!IsExtern && RE.IsPCRel)
59       makeValueAddendPCRel(Value, RelI, 1 << RE.Size);
60 
61     switch (RelType) {
62     UNIMPLEMENTED_RELOC(MachO::X86_64_RELOC_TLV);
63     default:
64       if (RelType > MachO::X86_64_RELOC_TLV)
65         return make_error<RuntimeDyldError>(("MachO X86_64 relocation type " +
66                                              Twine(RelType) +
67                                              " is out of range").str());
68       break;
69     }
70 
71     if (RE.RelType == MachO::X86_64_RELOC_GOT ||
72         RE.RelType == MachO::X86_64_RELOC_GOT_LOAD)
73       processGOTRelocation(RE, Value, Stubs);
74     else {
75       RE.Addend = Value.Offset;
76       if (Value.SymbolName)
77         addRelocationForSymbol(RE, Value.SymbolName);
78       else
79         addRelocationForSection(RE, Value.SectionID);
80     }
81 
82     return ++RelI;
83   }
84 
resolveRelocation(const RelocationEntry & RE,uint64_t Value)85   void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
86     LLVM_DEBUG(dumpRelocationToResolve(RE, Value));
87     const SectionEntry &Section = Sections[RE.SectionID];
88     uint8_t *LocalAddress = Section.getAddressWithOffset(RE.Offset);
89 
90     // If the relocation is PC-relative, the value to be encoded is the
91     // pointer difference.
92     if (RE.IsPCRel) {
93       // FIXME: It seems this value needs to be adjusted by 4 for an effective
94       // PC address. Is that expected? Only for branches, perhaps?
95       uint64_t FinalAddress = Section.getLoadAddressWithOffset(RE.Offset);
96       Value -= FinalAddress + 4;
97     }
98 
99     switch (RE.RelType) {
100     default:
101       llvm_unreachable("Invalid relocation type!");
102     case MachO::X86_64_RELOC_SIGNED_1:
103     case MachO::X86_64_RELOC_SIGNED_2:
104     case MachO::X86_64_RELOC_SIGNED_4:
105     case MachO::X86_64_RELOC_SIGNED:
106     case MachO::X86_64_RELOC_UNSIGNED:
107     case MachO::X86_64_RELOC_BRANCH:
108       writeBytesUnaligned(Value + RE.Addend, LocalAddress, 1 << RE.Size);
109       break;
110     case MachO::X86_64_RELOC_SUBTRACTOR: {
111       uint64_t SectionABase = Sections[RE.Sections.SectionA].getLoadAddress();
112       uint64_t SectionBBase = Sections[RE.Sections.SectionB].getLoadAddress();
113       assert((Value == SectionABase || Value == SectionBBase) &&
114              "Unexpected SUBTRACTOR relocation value.");
115       Value = SectionABase - SectionBBase + RE.Addend;
116       writeBytesUnaligned(Value, LocalAddress, 1 << RE.Size);
117       break;
118     }
119     }
120   }
121 
finalizeSection(const ObjectFile & Obj,unsigned SectionID,const SectionRef & Section)122   Error finalizeSection(const ObjectFile &Obj, unsigned SectionID,
123                         const SectionRef &Section) {
124     return Error::success();
125   }
126 
127 private:
processGOTRelocation(const RelocationEntry & RE,RelocationValueRef & Value,StubMap & Stubs)128   void processGOTRelocation(const RelocationEntry &RE,
129                             RelocationValueRef &Value, StubMap &Stubs) {
130     SectionEntry &Section = Sections[RE.SectionID];
131     assert(RE.IsPCRel);
132     assert(RE.Size == 2);
133     Value.Offset -= RE.Addend;
134     RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(Value);
135     uint8_t *Addr;
136     if (i != Stubs.end()) {
137       Addr = Section.getAddressWithOffset(i->second);
138     } else {
139       Stubs[Value] = Section.getStubOffset();
140       uint8_t *GOTEntry = Section.getAddressWithOffset(Section.getStubOffset());
141       RelocationEntry GOTRE(RE.SectionID, Section.getStubOffset(),
142                             MachO::X86_64_RELOC_UNSIGNED, Value.Offset, false,
143                             3);
144       if (Value.SymbolName)
145         addRelocationForSymbol(GOTRE, Value.SymbolName);
146       else
147         addRelocationForSection(GOTRE, Value.SectionID);
148       Section.advanceStubOffset(8);
149       Addr = GOTEntry;
150     }
151     RelocationEntry TargetRE(RE.SectionID, RE.Offset,
152                              MachO::X86_64_RELOC_UNSIGNED, RE.Addend, true, 2);
153     resolveRelocation(TargetRE, (uint64_t)Addr);
154   }
155 
156   Expected<relocation_iterator>
processSubtractRelocation(unsigned SectionID,relocation_iterator RelI,const MachOObjectFile & BaseObj,ObjSectionToIDMap & ObjSectionToID)157   processSubtractRelocation(unsigned SectionID, relocation_iterator RelI,
158                             const MachOObjectFile &BaseObj,
159                             ObjSectionToIDMap &ObjSectionToID) {
160     const MachOObjectFile &Obj =
161         static_cast<const MachOObjectFile&>(BaseObj);
162     MachO::any_relocation_info RE =
163         Obj.getRelocation(RelI->getRawDataRefImpl());
164 
165     unsigned Size = Obj.getAnyRelocationLength(RE);
166     uint64_t Offset = RelI->getOffset();
167     uint8_t *LocalAddress = Sections[SectionID].getAddressWithOffset(Offset);
168     unsigned NumBytes = 1 << Size;
169     int64_t Addend =
170       SignExtend64(readBytesUnaligned(LocalAddress, NumBytes), NumBytes * 8);
171 
172     unsigned SectionBID = ~0U;
173     uint64_t SectionBOffset = 0;
174 
175     MachO::any_relocation_info RelInfo =
176       Obj.getRelocation(RelI->getRawDataRefImpl());
177 
178     bool AIsExternal = BaseObj.getPlainRelocationExternal(RelInfo);
179 
180     if (AIsExternal) {
181       Expected<StringRef> SubtrahendNameOrErr = RelI->getSymbol()->getName();
182       if (!SubtrahendNameOrErr)
183         return SubtrahendNameOrErr.takeError();
184       auto SubtrahendI = GlobalSymbolTable.find(*SubtrahendNameOrErr);
185       SectionBID = SubtrahendI->second.getSectionID();
186       SectionBOffset = SubtrahendI->second.getOffset();
187     } else {
188       SectionRef SecB = Obj.getAnyRelocationSection(RelInfo);
189       bool IsCode = SecB.isText();
190       Expected<unsigned> SectionBIDOrErr =
191         findOrEmitSection(Obj, SecB, IsCode, ObjSectionToID);
192       if (!SectionBIDOrErr)
193         return SectionBIDOrErr.takeError();
194       SectionBID = *SectionBIDOrErr;
195       Addend += SecB.getAddress();
196     }
197 
198     ++RelI;
199 
200     unsigned SectionAID = ~0U;
201     uint64_t SectionAOffset = 0;
202 
203     RelInfo = Obj.getRelocation(RelI->getRawDataRefImpl());
204 
205     bool BIsExternal = BaseObj.getPlainRelocationExternal(RelInfo);
206     if (BIsExternal) {
207       Expected<StringRef> MinuendNameOrErr = RelI->getSymbol()->getName();
208       if (!MinuendNameOrErr)
209         return MinuendNameOrErr.takeError();
210       auto MinuendI = GlobalSymbolTable.find(*MinuendNameOrErr);
211       SectionAID = MinuendI->second.getSectionID();
212       SectionAOffset = MinuendI->second.getOffset();
213     } else {
214       SectionRef SecA = Obj.getAnyRelocationSection(RelInfo);
215       bool IsCode = SecA.isText();
216       Expected<unsigned> SectionAIDOrErr =
217         findOrEmitSection(Obj, SecA, IsCode, ObjSectionToID);
218       if (!SectionAIDOrErr)
219         return SectionAIDOrErr.takeError();
220       SectionAID = *SectionAIDOrErr;
221       Addend -= SecA.getAddress();
222     }
223 
224     RelocationEntry R(SectionID, Offset, MachO::X86_64_RELOC_SUBTRACTOR, (uint64_t)Addend,
225                       SectionAID, SectionAOffset, SectionBID, SectionBOffset,
226                       false, Size);
227 
228     addRelocationForSection(R, SectionAID);
229 
230     return ++RelI;
231   }
232 
233 };
234 }
235 
236 #undef DEBUG_TYPE
237 
238 #endif
239