1 //===-- RuntimeDyldCOFFX86_64.h --- COFF/X86_64 specific code ---*- 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 // COFF x86_x64 support for MC-JIT runtime dynamic linker.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFF86_64_H
15 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFF86_64_H
17 #include "../RuntimeDyldCOFF.h"
18 #include "llvm/BinaryFormat/COFF.h"
19 #include "llvm/Object/COFF.h"
21 #define DEBUG_TYPE "dyld"
25 class RuntimeDyldCOFFX86_64 : public RuntimeDyldCOFF {
28 // When a module is loaded we save the SectionID of the unwind
29 // sections in a table until we receive a request to register all
30 // unregisteredEH frame sections with the memory manager.
31 SmallVector<SID, 2> UnregisteredEHFrameSections;
32 SmallVector<SID, 2> RegisteredEHFrameSections;
35 // Fake an __ImageBase pointer by returning the section with the lowest adress
36 uint64_t getImageBase() {
38 ImageBase = std::numeric_limits<uint64_t>::max();
39 for (const SectionEntry &Section : Sections)
40 // The Sections list may contain sections that weren't loaded for
41 // whatever reason: they may be debug sections, and ProcessAllSections
42 // is false, or they may be sections that contain 0 bytes. If the
43 // section isn't loaded, the load address will be 0, and it should not
44 // be included in the ImageBase calculation.
45 if (Section.getLoadAddress() != 0)
46 ImageBase = std::min(ImageBase, Section.getLoadAddress());
51 void write32BitOffset(uint8_t *Target, int64_t Addend, uint64_t Delta) {
52 uint64_t Result = Addend + Delta;
53 assert(Result <= UINT32_MAX && "Relocation overflow");
54 writeBytesUnaligned(Result, Target, 4);
58 RuntimeDyldCOFFX86_64(RuntimeDyld::MemoryManager &MM,
59 JITSymbolResolver &Resolver)
60 : RuntimeDyldCOFF(MM, Resolver), ImageBase(0) {}
62 unsigned getStubAlignment() override { return 1; }
64 // 2-byte jmp instruction + 32-bit relative address + 64-bit absolute jump
65 unsigned getMaxStubSize() override { return 14; }
67 // The target location for the relocation is described by RE.SectionID and
68 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
69 // SectionEntry has three members describing its location.
70 // SectionEntry::Address is the address at which the section has been loaded
71 // into memory in the current (host) process. SectionEntry::LoadAddress is
72 // the address that the section will have in the target process.
73 // SectionEntry::ObjAddress is the address of the bits for this section in the
74 // original emitted object image (also in the current address space).
76 // Relocations will be applied as if the section were loaded at
77 // SectionEntry::LoadAddress, but they will be applied at an address based
78 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer
79 // to Target memory contents if they are required for value calculations.
81 // The Value parameter here is the load address of the symbol for the
82 // relocation to be applied. For relocations which refer to symbols in the
83 // current object Value will be the LoadAddress of the section in which
84 // the symbol resides (RE.Addend provides additional information about the
85 // symbol location). For external symbols, Value will be the address of the
86 // symbol in the target address space.
87 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
88 const SectionEntry &Section = Sections[RE.SectionID];
89 uint8_t *Target = Section.getAddressWithOffset(RE.Offset);
93 case COFF::IMAGE_REL_AMD64_REL32:
94 case COFF::IMAGE_REL_AMD64_REL32_1:
95 case COFF::IMAGE_REL_AMD64_REL32_2:
96 case COFF::IMAGE_REL_AMD64_REL32_3:
97 case COFF::IMAGE_REL_AMD64_REL32_4:
98 case COFF::IMAGE_REL_AMD64_REL32_5: {
99 uint64_t FinalAddress = Section.getLoadAddressWithOffset(RE.Offset);
100 // Delta is the distance from the start of the reloc to the end of the
101 // instruction with the reloc.
102 uint64_t Delta = 4 + (RE.RelType - COFF::IMAGE_REL_AMD64_REL32);
103 Value -= FinalAddress + Delta;
104 uint64_t Result = Value + RE.Addend;
105 assert(((int64_t)Result <= INT32_MAX) && "Relocation overflow");
106 assert(((int64_t)Result >= INT32_MIN) && "Relocation underflow");
107 writeBytesUnaligned(Result, Target, 4);
111 case COFF::IMAGE_REL_AMD64_ADDR32NB: {
112 // ADDR32NB requires an offset less than 2GB from 'ImageBase'.
113 // The MemoryManager can make sure this is always true by forcing the
114 // memory layout to be: CodeSection < ReadOnlySection < ReadWriteSection.
115 const uint64_t ImageBase = getImageBase();
116 if (Value < ImageBase || ((Value - ImageBase) > UINT32_MAX)) {
117 llvm::errs() << "IMAGE_REL_AMD64_ADDR32NB relocation requires an"
118 << "ordered section layout.\n";
119 write32BitOffset(Target, 0, 0);
121 write32BitOffset(Target, RE.Addend, Value - ImageBase);
126 case COFF::IMAGE_REL_AMD64_ADDR64: {
127 writeBytesUnaligned(Value + RE.Addend, Target, 8);
131 case COFF::IMAGE_REL_AMD64_SECREL: {
132 assert(static_cast<int64_t>(RE.Addend) <= INT32_MAX && "Relocation overflow");
133 assert(static_cast<int64_t>(RE.Addend) >= INT32_MIN && "Relocation underflow");
134 writeBytesUnaligned(RE.Addend, Target, 4);
139 llvm_unreachable("Relocation type not implemented yet!");
144 std::tuple<uint64_t, uint64_t, uint64_t>
145 generateRelocationStub(unsigned SectionID, StringRef TargetName,
146 uint64_t Offset, uint64_t RelType, uint64_t Addend,
148 uintptr_t StubOffset;
149 SectionEntry &Section = Sections[SectionID];
151 RelocationValueRef OriginalRelValueRef;
152 OriginalRelValueRef.SectionID = SectionID;
153 OriginalRelValueRef.Offset = Offset;
154 OriginalRelValueRef.Addend = Addend;
155 OriginalRelValueRef.SymbolName = TargetName.data();
157 auto Stub = Stubs.find(OriginalRelValueRef);
158 if (Stub == Stubs.end()) {
159 LLVM_DEBUG(dbgs() << " Create a new stub function for "
160 << TargetName.data() << "\n");
162 StubOffset = Section.getStubOffset();
163 Stubs[OriginalRelValueRef] = StubOffset;
164 createStubFunction(Section.getAddressWithOffset(StubOffset));
165 Section.advanceStubOffset(getMaxStubSize());
167 LLVM_DEBUG(dbgs() << " Stub function found for " << TargetName.data()
169 StubOffset = Stub->second;
172 // FIXME: If RelType == COFF::IMAGE_REL_AMD64_ADDR32NB we should be able
173 // to ignore the __ImageBase requirement and just forward to the stub
174 // directly as an offset of this section:
175 // write32BitOffset(Section.getAddressWithOffset(Offset), 0, StubOffset);
176 // .xdata exception handler's aren't having this though.
178 // Resolve original relocation to stub function.
179 const RelocationEntry RE(SectionID, Offset, RelType, Addend);
180 resolveRelocation(RE, Section.getLoadAddressWithOffset(StubOffset));
182 // adjust relocation info so resolution writes to the stub function
184 Offset = StubOffset + 6;
185 RelType = COFF::IMAGE_REL_AMD64_ADDR64;
187 return std::make_tuple(Offset, RelType, Addend);
190 Expected<relocation_iterator>
191 processRelocationRef(unsigned SectionID,
192 relocation_iterator RelI,
193 const ObjectFile &Obj,
194 ObjSectionToIDMap &ObjSectionToID,
195 StubMap &Stubs) override {
196 // If possible, find the symbol referred to in the relocation,
197 // and the section that contains it.
198 symbol_iterator Symbol = RelI->getSymbol();
199 if (Symbol == Obj.symbol_end())
200 report_fatal_error("Unknown symbol in relocation");
201 auto SectionOrError = Symbol->getSection();
203 return SectionOrError.takeError();
204 section_iterator SecI = *SectionOrError;
205 // If there is no section, this must be an external reference.
206 const bool IsExtern = SecI == Obj.section_end();
208 // Determine the Addend used to adjust the relocation value.
209 uint64_t RelType = RelI->getType();
210 uint64_t Offset = RelI->getOffset();
212 SectionEntry &Section = Sections[SectionID];
213 uintptr_t ObjTarget = Section.getObjAddress() + Offset;
215 Expected<StringRef> TargetNameOrErr = Symbol->getName();
216 if (!TargetNameOrErr)
217 return TargetNameOrErr.takeError();
218 StringRef TargetName = *TargetNameOrErr;
222 case COFF::IMAGE_REL_AMD64_REL32:
223 case COFF::IMAGE_REL_AMD64_REL32_1:
224 case COFF::IMAGE_REL_AMD64_REL32_2:
225 case COFF::IMAGE_REL_AMD64_REL32_3:
226 case COFF::IMAGE_REL_AMD64_REL32_4:
227 case COFF::IMAGE_REL_AMD64_REL32_5:
228 case COFF::IMAGE_REL_AMD64_ADDR32NB: {
229 uint8_t *Displacement = (uint8_t *)ObjTarget;
230 Addend = readBytesUnaligned(Displacement, 4);
233 std::tie(Offset, RelType, Addend) = generateRelocationStub(
234 SectionID, TargetName, Offset, RelType, Addend, Stubs);
239 case COFF::IMAGE_REL_AMD64_ADDR64: {
240 uint8_t *Displacement = (uint8_t *)ObjTarget;
241 Addend = readBytesUnaligned(Displacement, 8);
249 LLVM_DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset
250 << " RelType: " << RelType << " TargetName: "
251 << TargetName << " Addend " << Addend << "\n");
254 RelocationEntry RE(SectionID, Offset, RelType, Addend);
255 addRelocationForSymbol(RE, TargetName);
257 bool IsCode = SecI->isText();
258 unsigned TargetSectionID;
259 if (auto TargetSectionIDOrErr =
260 findOrEmitSection(Obj, *SecI, IsCode, ObjSectionToID))
261 TargetSectionID = *TargetSectionIDOrErr;
263 return TargetSectionIDOrErr.takeError();
264 uint64_t TargetOffset = getSymbolOffset(*Symbol);
265 RelocationEntry RE(SectionID, Offset, RelType, TargetOffset + Addend);
266 addRelocationForSection(RE, TargetSectionID);
272 void registerEHFrames() override {
273 for (auto const &EHFrameSID : UnregisteredEHFrameSections) {
274 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
275 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
276 size_t EHFrameSize = Sections[EHFrameSID].getSize();
277 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
278 RegisteredEHFrameSections.push_back(EHFrameSID);
280 UnregisteredEHFrameSections.clear();
283 Error finalizeLoad(const ObjectFile &Obj,
284 ObjSectionToIDMap &SectionMap) override {
285 // Look for and record the EH frame section IDs.
286 for (const auto &SectionPair : SectionMap) {
287 const SectionRef &Section = SectionPair.first;
289 if (auto EC = Section.getName(Name))
290 return errorCodeToError(EC);
292 // Note unwind info is stored in .pdata but often points to .xdata
293 // with an IMAGE_REL_AMD64_ADDR32NB relocation. Using a memory manager
294 // that keeps sections ordered in relation to __ImageBase is necessary.
295 if (Name == ".pdata")
296 UnregisteredEHFrameSections.push_back(SectionPair.second);
298 return Error::success();
302 } // end namespace llvm