LLVM 17.0.0git
RuntimeDyldCOFFX86_64.h
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1//===-- RuntimeDyldCOFFX86_64.h --- COFF/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// COFF x86_x64 support for MC-JIT runtime dynamic linker.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFF86_64_H
14#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFF86_64_H
15
16#include "../RuntimeDyldCOFF.h"
18#include "llvm/Object/COFF.h"
19
20#define DEBUG_TYPE "dyld"
21
22namespace llvm {
23
25
26private:
27 // When a module is loaded we save the SectionID of the unwind
28 // sections in a table until we receive a request to register all
29 // unregisteredEH frame sections with the memory manager.
30 SmallVector<SID, 2> UnregisteredEHFrameSections;
31 SmallVector<SID, 2> RegisteredEHFrameSections;
32 uint64_t ImageBase;
33
34 // Fake an __ImageBase pointer by returning the section with the lowest adress
35 uint64_t getImageBase() {
36 if (!ImageBase) {
37 ImageBase = std::numeric_limits<uint64_t>::max();
38 for (const SectionEntry &Section : Sections)
39 // The Sections list may contain sections that weren't loaded for
40 // whatever reason: they may be debug sections, and ProcessAllSections
41 // is false, or they may be sections that contain 0 bytes. If the
42 // section isn't loaded, the load address will be 0, and it should not
43 // be included in the ImageBase calculation.
44 if (Section.getLoadAddress() != 0)
45 ImageBase = std::min(ImageBase, Section.getLoadAddress());
46 }
47 return ImageBase;
48 }
49
50 void write32BitOffset(uint8_t *Target, int64_t Addend, uint64_t Delta) {
51 uint64_t Result = Addend + Delta;
52 assert(Result <= UINT32_MAX && "Relocation overflow");
53 writeBytesUnaligned(Result, Target, 4);
54 }
55
56public:
59 : RuntimeDyldCOFF(MM, Resolver, 8, COFF::IMAGE_REL_AMD64_ADDR64),
60 ImageBase(0) {}
61
62 Align getStubAlignment() override { return Align(1); }
63
64 // 2-byte jmp instruction + 32-bit relative address + 64-bit absolute jump
65 unsigned getMaxStubSize() const override { return 14; }
66
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).
75 //
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.
80 //
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);
90
91 switch (RE.RelType) {
92
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.
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);
108 break;
109 }
110
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 report_fatal_error("IMAGE_REL_AMD64_ADDR32NB relocation requires an "
118 "ordered section layout");
119 else {
120 write32BitOffset(Target, RE.Addend, Value - ImageBase);
121 }
122 break;
123 }
124
127 break;
128 }
129
131 assert(static_cast<int64_t>(RE.Addend) <= INT32_MAX && "Relocation overflow");
132 assert(static_cast<int64_t>(RE.Addend) >= INT32_MIN && "Relocation underflow");
134 break;
135 }
136
137 default:
138 llvm_unreachable("Relocation type not implemented yet!");
139 break;
140 }
141 }
142
143 std::tuple<uint64_t, uint64_t, uint64_t>
144 generateRelocationStub(unsigned SectionID, StringRef TargetName,
145 uint64_t Offset, uint64_t RelType, uint64_t Addend,
146 StubMap &Stubs) {
147 uintptr_t StubOffset;
148 SectionEntry &Section = Sections[SectionID];
149
150 RelocationValueRef OriginalRelValueRef;
151 OriginalRelValueRef.SectionID = SectionID;
152 OriginalRelValueRef.Offset = Offset;
153 OriginalRelValueRef.Addend = Addend;
154 OriginalRelValueRef.SymbolName = TargetName.data();
155
156 auto Stub = Stubs.find(OriginalRelValueRef);
157 if (Stub == Stubs.end()) {
158 LLVM_DEBUG(dbgs() << " Create a new stub function for "
159 << TargetName.data() << "\n");
160
161 StubOffset = Section.getStubOffset();
162 Stubs[OriginalRelValueRef] = StubOffset;
163 createStubFunction(Section.getAddressWithOffset(StubOffset));
164 Section.advanceStubOffset(getMaxStubSize());
165 } else {
166 LLVM_DEBUG(dbgs() << " Stub function found for " << TargetName.data()
167 << "\n");
168 StubOffset = Stub->second;
169 }
170
171 // FIXME: If RelType == COFF::IMAGE_REL_AMD64_ADDR32NB we should be able
172 // to ignore the __ImageBase requirement and just forward to the stub
173 // directly as an offset of this section:
174 // write32BitOffset(Section.getAddressWithOffset(Offset), 0, StubOffset);
175 // .xdata exception handler's aren't having this though.
176
177 // Resolve original relocation to stub function.
178 const RelocationEntry RE(SectionID, Offset, RelType, Addend);
179 resolveRelocation(RE, Section.getLoadAddressWithOffset(StubOffset));
180
181 // adjust relocation info so resolution writes to the stub function
182 Addend = 0;
183 Offset = StubOffset + 6;
185
186 return std::make_tuple(Offset, RelType, Addend);
187 }
188
190 processRelocationRef(unsigned SectionID,
192 const object::ObjectFile &Obj,
193 ObjSectionToIDMap &ObjSectionToID,
194 StubMap &Stubs) override {
195 // If possible, find the symbol referred to in the relocation,
196 // and the section that contains it.
197 object::symbol_iterator Symbol = RelI->getSymbol();
198 if (Symbol == Obj.symbol_end())
199 report_fatal_error("Unknown symbol in relocation");
200 auto SectionOrError = Symbol->getSection();
201 if (!SectionOrError)
202 return SectionOrError.takeError();
203 object::section_iterator SecI = *SectionOrError;
204 // If there is no section, this must be an external reference.
205 bool IsExtern = SecI == Obj.section_end();
206
207 // Determine the Addend used to adjust the relocation value.
208 uint64_t RelType = RelI->getType();
209 uint64_t Offset = RelI->getOffset();
210 uint64_t Addend = 0;
211 SectionEntry &Section = Sections[SectionID];
212 uintptr_t ObjTarget = Section.getObjAddress() + Offset;
213
214 Expected<StringRef> TargetNameOrErr = Symbol->getName();
215 if (!TargetNameOrErr)
216 return TargetNameOrErr.takeError();
217
218 StringRef TargetName = *TargetNameOrErr;
219 unsigned TargetSectionID = 0;
220 uint64_t TargetOffset = 0;
221
222 if (TargetName.startswith(getImportSymbolPrefix())) {
223 assert(IsExtern && "DLLImport not marked extern?");
224 TargetSectionID = SectionID;
225 TargetOffset = getDLLImportOffset(SectionID, Stubs, TargetName);
226 TargetName = StringRef();
227 IsExtern = false;
228 } else if (!IsExtern) {
229 if (auto TargetSectionIDOrErr =
230 findOrEmitSection(Obj, *SecI, SecI->isText(), ObjSectionToID))
231 TargetSectionID = *TargetSectionIDOrErr;
232 else
233 return TargetSectionIDOrErr.takeError();
234 TargetOffset = getSymbolOffset(*Symbol);
235 }
236
237 switch (RelType) {
238
246 uint8_t *Displacement = (uint8_t *)ObjTarget;
247 Addend = readBytesUnaligned(Displacement, 4);
248
249 if (IsExtern)
250 std::tie(Offset, RelType, Addend) = generateRelocationStub(
251 SectionID, TargetName, Offset, RelType, Addend, Stubs);
252
253 break;
254 }
255
257 uint8_t *Displacement = (uint8_t *)ObjTarget;
258 Addend = readBytesUnaligned(Displacement, 8);
259 break;
260 }
261
262 default:
263 break;
264 }
265
266 LLVM_DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset
267 << " RelType: " << RelType << " TargetName: "
268 << TargetName << " Addend " << Addend << "\n");
269
270 if (IsExtern) {
271 RelocationEntry RE(SectionID, Offset, RelType, Addend);
272 addRelocationForSymbol(RE, TargetName);
273 } else {
274 RelocationEntry RE(SectionID, Offset, RelType, TargetOffset + Addend);
275 addRelocationForSection(RE, TargetSectionID);
276 }
277
278 return ++RelI;
279 }
280
281 void registerEHFrames() override {
282 for (auto const &EHFrameSID : UnregisteredEHFrameSections) {
283 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
284 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
285 size_t EHFrameSize = Sections[EHFrameSID].getSize();
286 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
287 RegisteredEHFrameSections.push_back(EHFrameSID);
288 }
289 UnregisteredEHFrameSections.clear();
290 }
291
293 ObjSectionToIDMap &SectionMap) override {
294 // Look for and record the EH frame section IDs.
295 for (const auto &SectionPair : SectionMap) {
296 const object::SectionRef &Section = SectionPair.first;
297 Expected<StringRef> NameOrErr = Section.getName();
298 if (!NameOrErr)
299 return NameOrErr.takeError();
300
301 // Note unwind info is stored in .pdata but often points to .xdata
302 // with an IMAGE_REL_AMD64_ADDR32NB relocation. Using a memory manager
303 // that keeps sections ordered in relation to __ImageBase is necessary.
304 if ((*NameOrErr) == ".pdata")
305 UnregisteredEHFrameSections.push_back(SectionPair.second);
306 }
307 return Error::success();
308 }
309};
310
311} // end namespace llvm
312
313#undef DEBUG_TYPE
314
315#endif
#define LLVM_DEBUG(X)
Definition: Debug.h:101
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Lightweight error class with error context and mandatory checking.
Definition: Error.h:156
static ErrorSuccess success()
Create a success value.
Definition: Error.h:330
Tagged union holding either a T or a Error.
Definition: Error.h:470
Error takeError()
Take ownership of the stored error.
Definition: Error.h:597
Symbol resolution interface.
Definition: JITSymbol.h:371
RelocationEntry - used to represent relocations internally in the dynamic linker.
uint32_t RelType
RelType - relocation type.
uint64_t Offset
Offset - offset into the section.
int64_t Addend
Addend - the relocation addend encoded in the instruction itself.
unsigned SectionID
SectionID - the section this relocation points to.
Interface for looking up the initializer for a variable name, used by Init::resolveReferences.
Definition: Record.h:2137
void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override
A object file specific relocation resolver.
unsigned getMaxStubSize() const override
RuntimeDyldCOFFX86_64(RuntimeDyld::MemoryManager &MM, JITSymbolResolver &Resolver)
Error finalizeLoad(const object::ObjectFile &Obj, ObjSectionToIDMap &SectionMap) override
std::tuple< uint64_t, uint64_t, uint64_t > generateRelocationStub(unsigned SectionID, StringRef TargetName, uint64_t Offset, uint64_t RelType, uint64_t Addend, StubMap &Stubs)
Expected< object::relocation_iterator > processRelocationRef(unsigned SectionID, object::relocation_iterator RelI, const object::ObjectFile &Obj, ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) override
Parses one or more object file relocations (some object files use relocation pairs) and stores it to ...
uint64_t getSymbolOffset(const SymbolRef &Sym)
static constexpr StringRef getImportSymbolPrefix()
uint64_t getDLLImportOffset(unsigned SectionID, StubMap &Stubs, StringRef Name, bool SetSectionIDMinus1=false)
std::map< SectionRef, unsigned > ObjSectionToIDMap
std::map< RelocationValueRef, uintptr_t > StubMap
void addRelocationForSymbol(const RelocationEntry &RE, StringRef SymbolName)
RuntimeDyld::MemoryManager & MemMgr
void addRelocationForSection(const RelocationEntry &RE, unsigned SectionID)
Expected< unsigned > findOrEmitSection(const ObjectFile &Obj, const SectionRef &Section, bool IsCode, ObjSectionToIDMap &LocalSections)
Find Section in LocalSections.
void writeBytesUnaligned(uint64_t Value, uint8_t *Dst, unsigned Size) const
Endian-aware write.
uint8_t * createStubFunction(uint8_t *Addr, unsigned AbiVariant=0)
Emits long jump instruction to Addr.
uint64_t readBytesUnaligned(uint8_t *Src, unsigned Size) const
Endian-aware read Read the least significant Size bytes from Src.
virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size)=0
Register the EH frames with the runtime so that c++ exceptions work.
SectionEntry - represents a section emitted into memory by the dynamic linker.
void push_back(const T &Elt)
Definition: SmallVector.h:416
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1200
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
bool startswith(StringRef Prefix) const
Definition: StringRef.h:261
const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:131
Target - Wrapper for Target specific information.
LLVM Value Representation.
Definition: Value.h:74
This class is the base class for all object file types.
Definition: ObjectFile.h:228
virtual section_iterator section_end() const =0
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:80
virtual basic_symbol_iterator symbol_end() const =0
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
@ IMAGE_REL_AMD64_REL32
Definition: COFF.h:350
@ IMAGE_REL_AMD64_REL32_5
Definition: COFF.h:355
@ IMAGE_REL_AMD64_ADDR64
Definition: COFF.h:347
@ IMAGE_REL_AMD64_REL32_3
Definition: COFF.h:353
@ IMAGE_REL_AMD64_ADDR32NB
Definition: COFF.h:349
@ IMAGE_REL_AMD64_REL32_2
Definition: COFF.h:352
@ IMAGE_REL_AMD64_REL32_1
Definition: COFF.h:351
@ IMAGE_REL_AMD64_SECREL
Definition: COFF.h:357
@ IMAGE_REL_AMD64_REL32_4
Definition: COFF.h:354
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
@ Offset
Definition: DWP.cpp:406
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:145
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39