1 //===----- COFF_x86_64.cpp - JIT linker implementation for COFF/x86_64 ----===//
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_64 jit-link implementation.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "llvm/ExecutionEngine/JITLink/COFF_x86_64.h"
14 #include "COFFLinkGraphBuilder.h"
15 #include "JITLinkGeneric.h"
16 #include "SEHFrameSupport.h"
17 #include "llvm/BinaryFormat/COFF.h"
18 #include "llvm/ExecutionEngine/JITLink/x86_64.h"
19 #include "llvm/Object/COFF.h"
20 #include "llvm/Support/Endian.h"
21
22 #define DEBUG_TYPE "jitlink"
23
24 using namespace llvm;
25 using namespace llvm::jitlink;
26
27 namespace {
28
29 enum EdgeKind_coff_x86_64 : Edge::Kind {
30 PCRel32 = x86_64::FirstPlatformRelocation,
31 Pointer32NB,
32 Pointer64,
33 SectionIdx16,
34 SecRel32,
35 };
36
37 class COFFJITLinker_x86_64 : public JITLinker<COFFJITLinker_x86_64> {
38 friend class JITLinker<COFFJITLinker_x86_64>;
39
40 public:
COFFJITLinker_x86_64(std::unique_ptr<JITLinkContext> Ctx,std::unique_ptr<LinkGraph> G,PassConfiguration PassConfig)41 COFFJITLinker_x86_64(std::unique_ptr<JITLinkContext> Ctx,
42 std::unique_ptr<LinkGraph> G,
43 PassConfiguration PassConfig)
44 : JITLinker(std::move(Ctx), std::move(G), std::move(PassConfig)) {}
45
46 private:
applyFixup(LinkGraph & G,Block & B,const Edge & E) const47 Error applyFixup(LinkGraph &G, Block &B, const Edge &E) const {
48 return x86_64::applyFixup(G, B, E, nullptr);
49 }
50 };
51
52 class COFFLinkGraphBuilder_x86_64 : public COFFLinkGraphBuilder {
53 private:
addRelocations()54 Error addRelocations() override {
55 LLVM_DEBUG(dbgs() << "Processing relocations:\n");
56
57 for (const auto &RelSect : sections())
58 if (Error Err = COFFLinkGraphBuilder::forEachRelocation(
59 RelSect, this, &COFFLinkGraphBuilder_x86_64::addSingleRelocation))
60 return Err;
61
62 return Error::success();
63 }
64
addSingleRelocation(const object::RelocationRef & Rel,const object::SectionRef & FixupSect,Block & BlockToFix)65 Error addSingleRelocation(const object::RelocationRef &Rel,
66 const object::SectionRef &FixupSect,
67 Block &BlockToFix) {
68 const object::coff_relocation *COFFRel = getObject().getCOFFRelocation(Rel);
69 auto SymbolIt = Rel.getSymbol();
70 if (SymbolIt == getObject().symbol_end()) {
71 return make_error<StringError>(
72 formatv("Invalid symbol index in relocation entry. "
73 "index: {0}, section: {1}",
74 COFFRel->SymbolTableIndex, FixupSect.getIndex()),
75 inconvertibleErrorCode());
76 }
77
78 object::COFFSymbolRef COFFSymbol = getObject().getCOFFSymbol(*SymbolIt);
79 COFFSymbolIndex SymIndex = getObject().getSymbolIndex(COFFSymbol);
80
81 Symbol *GraphSymbol = getGraphSymbol(SymIndex);
82 if (!GraphSymbol)
83 return make_error<StringError>(
84 formatv("Could not find symbol at given index, did you add it to "
85 "JITSymbolTable? index: {0}, section: {1}",
86 SymIndex, FixupSect.getIndex()),
87 inconvertibleErrorCode());
88
89 int64_t Addend = 0;
90 orc::ExecutorAddr FixupAddress =
91 orc::ExecutorAddr(FixupSect.getAddress()) + Rel.getOffset();
92 Edge::OffsetT Offset = FixupAddress - BlockToFix.getAddress();
93
94 Edge::Kind Kind = Edge::Invalid;
95 const char *FixupPtr = BlockToFix.getContent().data() + Offset;
96
97 switch (Rel.getType()) {
98 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_ADDR32NB: {
99 Kind = EdgeKind_coff_x86_64::Pointer32NB;
100 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
101 break;
102 }
103 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_REL32: {
104 Kind = EdgeKind_coff_x86_64::PCRel32;
105 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
106 break;
107 }
108 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_REL32_1: {
109 Kind = EdgeKind_coff_x86_64::PCRel32;
110 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
111 Addend -= 1;
112 break;
113 }
114 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_REL32_2: {
115 Kind = EdgeKind_coff_x86_64::PCRel32;
116 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
117 Addend -= 2;
118 break;
119 }
120 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_REL32_3: {
121 Kind = EdgeKind_coff_x86_64::PCRel32;
122 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
123 Addend -= 3;
124 break;
125 }
126 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_REL32_4: {
127 Kind = EdgeKind_coff_x86_64::PCRel32;
128 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
129 Addend -= 4;
130 break;
131 }
132 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_REL32_5: {
133 Kind = EdgeKind_coff_x86_64::PCRel32;
134 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
135 Addend -= 5;
136 break;
137 }
138 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_ADDR64: {
139 Kind = EdgeKind_coff_x86_64::Pointer64;
140 Addend = *reinterpret_cast<const support::little64_t *>(FixupPtr);
141 break;
142 }
143 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_SECTION: {
144 Kind = EdgeKind_coff_x86_64::SectionIdx16;
145 Addend = *reinterpret_cast<const support::little16_t *>(FixupPtr);
146 uint64_t SectionIdx = 0;
147 if (COFFSymbol.isAbsolute())
148 SectionIdx = getObject().getNumberOfSections() + 1;
149 else
150 SectionIdx = COFFSymbol.getSectionNumber();
151 auto *AbsSym = &getGraph().addAbsoluteSymbol(
152 "secidx", orc::ExecutorAddr(SectionIdx), 2, Linkage::Strong,
153 Scope::Local, false);
154 GraphSymbol = AbsSym;
155 break;
156 }
157 case COFF::RelocationTypeAMD64::IMAGE_REL_AMD64_SECREL: {
158 // FIXME: SECREL to external symbol should be handled
159 if (!GraphSymbol->isDefined())
160 return Error::success();
161 Kind = EdgeKind_coff_x86_64::SecRel32;
162 Addend = *reinterpret_cast<const support::little32_t *>(FixupPtr);
163 break;
164 }
165 default: {
166 return make_error<JITLinkError>("Unsupported x86_64 relocation:" +
167 formatv("{0:d}", Rel.getType()));
168 }
169 };
170
171 Edge GE(Kind, Offset, *GraphSymbol, Addend);
172 LLVM_DEBUG({
173 dbgs() << " ";
174 printEdge(dbgs(), BlockToFix, GE, getCOFFX86RelocationKindName(Kind));
175 dbgs() << "\n";
176 });
177
178 BlockToFix.addEdge(std::move(GE));
179
180 return Error::success();
181 }
182
183 public:
COFFLinkGraphBuilder_x86_64(const object::COFFObjectFile & Obj,const Triple T,const SubtargetFeatures Features)184 COFFLinkGraphBuilder_x86_64(const object::COFFObjectFile &Obj, const Triple T,
185 const SubtargetFeatures Features)
186 : COFFLinkGraphBuilder(Obj, std::move(T), std::move(Features),
187 getCOFFX86RelocationKindName) {}
188 };
189
190 class COFFLinkGraphLowering_x86_64 {
191 public:
192 // Lowers COFF x86_64 specific edges to generic x86_64 edges.
lowerCOFFRelocationEdges(LinkGraph & G,JITLinkContext & Ctx)193 Error lowerCOFFRelocationEdges(LinkGraph &G, JITLinkContext &Ctx) {
194 for (auto *B : G.blocks()) {
195 for (auto &E : B->edges()) {
196 switch (E.getKind()) {
197 case EdgeKind_coff_x86_64::Pointer32NB: {
198 auto ImageBase = getImageBaseAddress(G, Ctx);
199 if (!ImageBase)
200 return ImageBase.takeError();
201 E.setAddend(E.getAddend() - ImageBase->getValue());
202 E.setKind(x86_64::Pointer32);
203 break;
204 }
205 case EdgeKind_coff_x86_64::PCRel32: {
206 E.setKind(x86_64::PCRel32);
207 break;
208 }
209 case EdgeKind_coff_x86_64::Pointer64: {
210 E.setKind(x86_64::Pointer64);
211 break;
212 }
213 case EdgeKind_coff_x86_64::SectionIdx16: {
214 E.setKind(x86_64::Pointer16);
215 break;
216 }
217 case EdgeKind_coff_x86_64::SecRel32: {
218 E.setAddend(E.getAddend() -
219 getSectionStart(E.getTarget().getBlock().getSection())
220 .getValue());
221 E.setKind(x86_64::Pointer32);
222 break;
223 }
224 default:
225 break;
226 }
227 }
228 }
229 return Error::success();
230 }
231
232 private:
getImageBaseSymbolName()233 static StringRef getImageBaseSymbolName() { return "__ImageBase"; }
234
getSectionStart(Section & Sec)235 orc::ExecutorAddr getSectionStart(Section &Sec) {
236 if (!SectionStartCache.count(&Sec)) {
237 SectionRange Range(Sec);
238 SectionStartCache[&Sec] = Range.getStart();
239 }
240 return SectionStartCache[&Sec];
241 }
242
getImageBaseAddress(LinkGraph & G,JITLinkContext & Ctx)243 Expected<orc::ExecutorAddr> getImageBaseAddress(LinkGraph &G,
244 JITLinkContext &Ctx) {
245 if (this->ImageBase)
246 return this->ImageBase;
247 for (auto *S : G.defined_symbols())
248 if (S->getName() == getImageBaseSymbolName()) {
249 this->ImageBase = S->getAddress();
250 return this->ImageBase;
251 }
252
253 JITLinkContext::LookupMap Symbols;
254 Symbols[getImageBaseSymbolName()] = SymbolLookupFlags::RequiredSymbol;
255 orc::ExecutorAddr ImageBase;
256 Error Err = Error::success();
257 Ctx.lookup(Symbols,
258 createLookupContinuation([&](Expected<AsyncLookupResult> LR) {
259 ErrorAsOutParameter EAO(&Err);
260 if (!LR) {
261 Err = LR.takeError();
262 return;
263 }
264 ImageBase = LR->begin()->second.getAddress();
265 }));
266 if (Err)
267 return std::move(Err);
268 this->ImageBase = ImageBase;
269 return ImageBase;
270 }
271
272 DenseMap<Section *, orc::ExecutorAddr> SectionStartCache;
273 orc::ExecutorAddr ImageBase;
274 };
275
lowerEdges_COFF_x86_64(LinkGraph & G,JITLinkContext * Ctx)276 Error lowerEdges_COFF_x86_64(LinkGraph &G, JITLinkContext *Ctx) {
277 LLVM_DEBUG(dbgs() << "Lowering COFF x86_64 edges:\n");
278 COFFLinkGraphLowering_x86_64 GraphLowering;
279
280 if (auto Err = GraphLowering.lowerCOFFRelocationEdges(G, *Ctx))
281 return Err;
282
283 return Error::success();
284 }
285 } // namespace
286
287 namespace llvm {
288 namespace jitlink {
289
290 /// Return the string name of the given COFF x86_64 edge kind.
getCOFFX86RelocationKindName(Edge::Kind R)291 const char *getCOFFX86RelocationKindName(Edge::Kind R) {
292 switch (R) {
293 case PCRel32:
294 return "PCRel32";
295 case Pointer32NB:
296 return "Pointer32NB";
297 case Pointer64:
298 return "Pointer64";
299 case SectionIdx16:
300 return "SectionIdx16";
301 case SecRel32:
302 return "SecRel32";
303 default:
304 return x86_64::getEdgeKindName(R);
305 }
306 }
307
308 Expected<std::unique_ptr<LinkGraph>>
createLinkGraphFromCOFFObject_x86_64(MemoryBufferRef ObjectBuffer)309 createLinkGraphFromCOFFObject_x86_64(MemoryBufferRef ObjectBuffer) {
310 LLVM_DEBUG({
311 dbgs() << "Building jitlink graph for new input "
312 << ObjectBuffer.getBufferIdentifier() << "...\n";
313 });
314
315 auto COFFObj = object::ObjectFile::createCOFFObjectFile(ObjectBuffer);
316 if (!COFFObj)
317 return COFFObj.takeError();
318
319 auto Features = (*COFFObj)->getFeatures();
320 if (!Features)
321 return Features.takeError();
322
323 return COFFLinkGraphBuilder_x86_64(**COFFObj, (*COFFObj)->makeTriple(),
324 std::move(*Features))
325 .buildGraph();
326 }
327
link_COFF_x86_64(std::unique_ptr<LinkGraph> G,std::unique_ptr<JITLinkContext> Ctx)328 void link_COFF_x86_64(std::unique_ptr<LinkGraph> G,
329 std::unique_ptr<JITLinkContext> Ctx) {
330 PassConfiguration Config;
331 const Triple &TT = G->getTargetTriple();
332 if (Ctx->shouldAddDefaultTargetPasses(TT)) {
333 // Add a mark-live pass.
334 if (auto MarkLive = Ctx->getMarkLivePass(TT)) {
335 Config.PrePrunePasses.push_back(std::move(MarkLive));
336 Config.PrePrunePasses.push_back(SEHFrameKeepAlivePass(".pdata"));
337 } else
338 Config.PrePrunePasses.push_back(markAllSymbolsLive);
339
340 // Add COFF edge lowering passes.
341 JITLinkContext *CtxPtr = Ctx.get();
342 Config.PreFixupPasses.push_back(
343 [CtxPtr](LinkGraph &G) { return lowerEdges_COFF_x86_64(G, CtxPtr); });
344 }
345
346 if (auto Err = Ctx->modifyPassConfig(*G, Config))
347 return Ctx->notifyFailed(std::move(Err));
348
349 COFFJITLinker_x86_64::link(std::move(Ctx), std::move(G), std::move(Config));
350 }
351
352 } // namespace jitlink
353 } // namespace llvm
354