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
24using namespace llvm;
25using namespace llvm::jitlink;
26
27namespace {
28
29enum EdgeKind_coff_x86_64 : Edge::Kind {
30 PCRel32 = x86_64::FirstPlatformRelocation,
31 Pointer32NB,
32 Pointer64,
33 SectionIdx16,
34 SecRel32,
35};
36
37class COFFJITLinker_x86_64 : public JITLinker<COFFJITLinker_x86_64> {
38 friend class JITLinker<COFFJITLinker_x86_64>;
39
40public:
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
46private:
47 Error applyFixup(LinkGraph &G, Block &B, const Edge &E) const {
48 return x86_64::applyFixup(G, B, E, GOTSymbol: nullptr);
49 }
50};
51
52class COFFLinkGraphBuilder_x86_64 : public COFFLinkGraphBuilder {
53private:
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 RelSec: RelSect, Instance: this, Method: &COFFLinkGraphBuilder_x86_64::addSingleRelocation))
60 return Err;
61
62 return Error::success();
63 }
64
65 Error addSingleRelocation(const object::RelocationRef &Rel,
66 const object::SectionRef &FixupSect,
67 Block &BlockToFix) {
68 const object::coff_relocation *COFFRel = getObject().getCOFFRelocation(Reloc: Rel);
69 auto SymbolIt = Rel.getSymbol();
70 if (SymbolIt == getObject().symbol_end()) {
71 return make_error<StringError>(
72 Args: formatv(Fmt: "Invalid symbol index in relocation entry. "
73 "index: {0}, section: {1}",
74 Vals: COFFRel->SymbolTableIndex, Vals: FixupSect.getIndex()),
75 Args: inconvertibleErrorCode());
76 }
77
78 object::COFFSymbolRef COFFSymbol = getObject().getCOFFSymbol(Symbol: *SymbolIt);
79 COFFSymbolIndex SymIndex = getObject().getSymbolIndex(Symbol: COFFSymbol);
80
81 Symbol *GraphSymbol = getGraphSymbol(SymIndex);
82 if (!GraphSymbol)
83 return make_error<StringError>(
84 Args: formatv(Fmt: "Could not find symbol at given index, did you add it to "
85 "JITSymbolTable? index: {0}, section: {1}",
86 Vals&: SymIndex, Vals: FixupSect.getIndex()),
87 Args: 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 Name: "secidx", Address: orc::ExecutorAddr(SectionIdx), Size: 2, L: Linkage::Strong,
153 S: Scope::Local, IsLive: 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>(Args: "Unsupported x86_64 relocation:" +
167 formatv(Fmt: "{0:d}", Vals: 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(E: std::move(GE));
179
180 return Error::success();
181 }
182
183public:
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
190class COFFLinkGraphLowering_x86_64 {
191public:
192 // Lowers COFF x86_64 specific edges to generic x86_64 edges.
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(Sec&: 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
232private:
233 static StringRef getImageBaseSymbolName() { return "__ImageBase"; }
234
235 orc::ExecutorAddr getSectionStart(Section &Sec) {
236 if (!SectionStartCache.count(Val: &Sec)) {
237 SectionRange Range(Sec);
238 SectionStartCache[&Sec] = Range.getStart();
239 }
240 return SectionStartCache[&Sec];
241 }
242
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 LC: createLookupContinuation(Cont: [&](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
276Error 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&: *Ctx))
281 return Err;
282
283 return Error::success();
284}
285} // namespace
286
287namespace llvm {
288namespace jitlink {
289
290/// Return the string name of the given COFF x86_64 edge kind.
291const 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(K: R);
305 }
306}
307
308Expected<std::unique_ptr<LinkGraph>>
309createLinkGraphFromCOFFObject_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(Object: 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
328void 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(x: std::move(MarkLive));
336 Config.PrePrunePasses.push_back(x: SEHFrameKeepAlivePass(".pdata"));
337 } else
338 Config.PrePrunePasses.push_back(x: markAllSymbolsLive);
339
340 // Add COFF edge lowering passes.
341 JITLinkContext *CtxPtr = Ctx.get();
342 Config.PreFixupPasses.push_back(
343 x: [CtxPtr](LinkGraph &G) { return lowerEdges_COFF_x86_64(G, Ctx: CtxPtr); });
344 }
345
346 if (auto Err = Ctx->modifyPassConfig(G&: *G, Config))
347 return Ctx->notifyFailed(Err: std::move(Err));
348
349 COFFJITLinker_x86_64::link(Args: std::move(Ctx), Args: std::move(G), Args: std::move(Config));
350}
351
352} // namespace jitlink
353} // namespace llvm
354