xref: /llvm-project/llvm/lib/ExecutionEngine/JITLink/ELF_riscv.cpp (revision 26ee8947702d79ce2cab8e577f713685a5ca4a55)
1 //===------- ELF_riscv.cpp -JIT linker implementation for ELF/riscv -------===//
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 // ELF/riscv jit-link implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/ExecutionEngine/JITLink/ELF_riscv.h"
14 #include "ELFLinkGraphBuilder.h"
15 #include "JITLinkGeneric.h"
16 #include "PerGraphGOTAndPLTStubsBuilder.h"
17 #include "llvm/BinaryFormat/ELF.h"
18 #include "llvm/ExecutionEngine/JITLink/JITLink.h"
19 #include "llvm/ExecutionEngine/JITLink/riscv.h"
20 #include "llvm/Object/ELF.h"
21 #include "llvm/Object/ELFObjectFile.h"
22 #include "llvm/Support/Endian.h"
23 
24 #define DEBUG_TYPE "jitlink"
25 using namespace llvm;
26 using namespace llvm::jitlink;
27 using namespace llvm::jitlink::riscv;
28 
29 namespace {
30 
31 class PerGraphGOTAndPLTStubsBuilder_ELF_riscv
32     : public PerGraphGOTAndPLTStubsBuilder<
33           PerGraphGOTAndPLTStubsBuilder_ELF_riscv> {
34 public:
35   static constexpr size_t StubEntrySize = 16;
36   static const uint8_t NullGOTEntryContent[8];
37   static const uint8_t RV64StubContent[StubEntrySize];
38   static const uint8_t RV32StubContent[StubEntrySize];
39 
40   using PerGraphGOTAndPLTStubsBuilder<
41       PerGraphGOTAndPLTStubsBuilder_ELF_riscv>::PerGraphGOTAndPLTStubsBuilder;
42 
43   bool isRV64() const { return G.getPointerSize() == 8; }
44 
45   bool isGOTEdgeToFix(Edge &E) const { return E.getKind() == R_RISCV_GOT_HI20; }
46 
47   Symbol &createGOTEntry(Symbol &Target) {
48     Block &GOTBlock =
49         G.createContentBlock(getGOTSection(), getGOTEntryBlockContent(),
50                              orc::ExecutorAddr(), G.getPointerSize(), 0);
51     GOTBlock.addEdge(isRV64() ? R_RISCV_64 : R_RISCV_32, 0, Target, 0);
52     return G.addAnonymousSymbol(GOTBlock, 0, G.getPointerSize(), false, false);
53   }
54 
55   Symbol &createPLTStub(Symbol &Target) {
56     Block &StubContentBlock = G.createContentBlock(
57         getStubsSection(), getStubBlockContent(), orc::ExecutorAddr(), 4, 0);
58     auto &GOTEntrySymbol = getGOTEntry(Target);
59     StubContentBlock.addEdge(R_RISCV_CALL, 0, GOTEntrySymbol, 0);
60     return G.addAnonymousSymbol(StubContentBlock, 0, StubEntrySize, true,
61                                 false);
62   }
63 
64   void fixGOTEdge(Edge &E, Symbol &GOTEntry) {
65     // Replace the relocation pair (R_RISCV_GOT_HI20, R_RISCV_PCREL_LO12)
66     // with (R_RISCV_PCREL_HI20, R_RISCV_PCREL_LO12)
67     // Therefore, here just change the R_RISCV_GOT_HI20 to R_RISCV_PCREL_HI20
68     E.setKind(R_RISCV_PCREL_HI20);
69     E.setTarget(GOTEntry);
70   }
71 
72   void fixPLTEdge(Edge &E, Symbol &PLTStubs) {
73     assert(E.getKind() == R_RISCV_CALL_PLT && "Not a R_RISCV_CALL_PLT edge?");
74     E.setKind(R_RISCV_CALL);
75     E.setTarget(PLTStubs);
76   }
77 
78   bool isExternalBranchEdge(Edge &E) const {
79     return (E.getKind() == R_RISCV_CALL || E.getKind() == R_RISCV_CALL_PLT) &&
80            !E.getTarget().isDefined();
81   }
82 
83 private:
84   Section &getGOTSection() const {
85     if (!GOTSection)
86       GOTSection = &G.createSection("$__GOT", orc::MemProt::Read);
87     return *GOTSection;
88   }
89 
90   Section &getStubsSection() const {
91     if (!StubsSection)
92       StubsSection =
93           &G.createSection("$__STUBS", orc::MemProt::Read | orc::MemProt::Exec);
94     return *StubsSection;
95   }
96 
97   ArrayRef<char> getGOTEntryBlockContent() {
98     return {reinterpret_cast<const char *>(NullGOTEntryContent),
99             G.getPointerSize()};
100   }
101 
102   ArrayRef<char> getStubBlockContent() {
103     auto StubContent = isRV64() ? RV64StubContent : RV32StubContent;
104     return {reinterpret_cast<const char *>(StubContent), StubEntrySize};
105   }
106 
107   mutable Section *GOTSection = nullptr;
108   mutable Section *StubsSection = nullptr;
109 };
110 
111 const uint8_t PerGraphGOTAndPLTStubsBuilder_ELF_riscv::NullGOTEntryContent[8] =
112     {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
113 
114 const uint8_t
115     PerGraphGOTAndPLTStubsBuilder_ELF_riscv::RV64StubContent[StubEntrySize] = {
116         0x17, 0x0e, 0x00, 0x00,  // auipc t3, literal
117         0x03, 0x3e, 0x0e, 0x00,  // ld    t3, literal(t3)
118         0x67, 0x00, 0x0e, 0x00,  // jr    t3
119         0x13, 0x00, 0x00, 0x00}; // nop
120 
121 const uint8_t
122     PerGraphGOTAndPLTStubsBuilder_ELF_riscv::RV32StubContent[StubEntrySize] = {
123         0x17, 0x0e, 0x00, 0x00,  // auipc t3, literal
124         0x03, 0x2e, 0x0e, 0x00,  // lw    t3, literal(t3)
125         0x67, 0x00, 0x0e, 0x00,  // jr    t3
126         0x13, 0x00, 0x00, 0x00}; // nop
127 } // namespace
128 namespace llvm {
129 namespace jitlink {
130 
131 static Expected<const Edge &> getRISCVPCRelHi20(const Edge &E) {
132   using namespace riscv;
133   assert((E.getKind() == R_RISCV_PCREL_LO12_I ||
134           E.getKind() == R_RISCV_PCREL_LO12_S) &&
135          "Can only have high relocation for R_RISCV_PCREL_LO12_I or "
136          "R_RISCV_PCREL_LO12_S");
137 
138   const Symbol &Sym = E.getTarget();
139   const Block &B = Sym.getBlock();
140   orc::ExecutorAddrDiff Offset = Sym.getOffset();
141 
142   struct Comp {
143     bool operator()(const Edge &Lhs, orc::ExecutorAddrDiff Offset) {
144       return Lhs.getOffset() < Offset;
145     }
146     bool operator()(orc::ExecutorAddrDiff Offset, const Edge &Rhs) {
147       return Offset < Rhs.getOffset();
148     }
149   };
150 
151   auto Bound =
152       std::equal_range(B.edges().begin(), B.edges().end(), Offset, Comp{});
153 
154   for (auto It = Bound.first; It != Bound.second; ++It) {
155     if (It->getKind() == R_RISCV_PCREL_HI20)
156       return *It;
157   }
158 
159   return make_error<JITLinkError>(
160       "No HI20 PCREL relocation type be found for LO12 PCREL relocation type");
161 }
162 
163 static uint32_t extractBits(uint32_t Num, unsigned Low, unsigned Size) {
164   return (Num & (((1ULL << Size) - 1) << Low)) >> Low;
165 }
166 
167 static inline bool isAlignmentCorrect(uint64_t Value, int N) {
168   return (Value & (N - 1)) ? false : true;
169 }
170 
171 // Requires 0 < N <= 64.
172 static inline bool isInRangeForImm(int64_t Value, int N) {
173   return Value == llvm::SignExtend64(Value, N);
174 }
175 
176 class ELFJITLinker_riscv : public JITLinker<ELFJITLinker_riscv> {
177   friend class JITLinker<ELFJITLinker_riscv>;
178 
179 public:
180   ELFJITLinker_riscv(std::unique_ptr<JITLinkContext> Ctx,
181                      std::unique_ptr<LinkGraph> G, PassConfiguration PassConfig)
182       : JITLinker(std::move(Ctx), std::move(G), std::move(PassConfig)) {}
183 
184 private:
185   Error applyFixup(LinkGraph &G, Block &B, const Edge &E) const {
186     using namespace riscv;
187     using namespace llvm::support;
188 
189     char *BlockWorkingMem = B.getAlreadyMutableContent().data();
190     char *FixupPtr = BlockWorkingMem + E.getOffset();
191     orc::ExecutorAddr FixupAddress = B.getAddress() + E.getOffset();
192     switch (E.getKind()) {
193     case R_RISCV_32: {
194       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
195       *(little32_t *)FixupPtr = static_cast<uint32_t>(Value);
196       break;
197     }
198     case R_RISCV_64: {
199       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
200       *(little64_t *)FixupPtr = static_cast<uint64_t>(Value);
201       break;
202     }
203     case R_RISCV_BRANCH: {
204       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
205       if (LLVM_UNLIKELY(!isInRangeForImm(Value >> 1, 12)))
206         return makeTargetOutOfRangeError(G, B, E);
207       if (LLVM_UNLIKELY(!isAlignmentCorrect(Value, 2)))
208         return makeAlignmentError(FixupAddress, Value, 2, E);
209       uint32_t Imm12 = extractBits(Value, 12, 1) << 31;
210       uint32_t Imm10_5 = extractBits(Value, 5, 6) << 25;
211       uint32_t Imm4_1 = extractBits(Value, 1, 4) << 8;
212       uint32_t Imm11 = extractBits(Value, 11, 1) << 7;
213       uint32_t RawInstr = *(little32_t *)FixupPtr;
214       *(little32_t *)FixupPtr =
215           (RawInstr & 0x1FFF07F) | Imm12 | Imm10_5 | Imm4_1 | Imm11;
216       break;
217     }
218     case R_RISCV_JAL: {
219       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
220       if (LLVM_UNLIKELY(!isInRangeForImm(Value >> 1, 20)))
221         return makeTargetOutOfRangeError(G, B, E);
222       if (LLVM_UNLIKELY(!isAlignmentCorrect(Value, 2)))
223         return makeAlignmentError(FixupAddress, Value, 2, E);
224       uint32_t Imm20 = extractBits(Value, 20, 1) << 31;
225       uint32_t Imm10_1 = extractBits(Value, 1, 10) << 21;
226       uint32_t Imm11 = extractBits(Value, 11, 1) << 20;
227       uint32_t Imm19_12 = extractBits(Value, 12, 8) << 12;
228       uint32_t RawInstr = *(little32_t *)FixupPtr;
229       *(little32_t *)FixupPtr =
230           (RawInstr & 0xFFF) | Imm20 | Imm10_1 | Imm11 | Imm19_12;
231       break;
232     }
233     case R_RISCV_CALL_PLT:
234     case R_RISCV_CALL: {
235       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
236       int64_t Hi = Value + 0x800;
237       if (LLVM_UNLIKELY(!isInRangeForImm(Hi, 32)))
238         return makeTargetOutOfRangeError(G, B, E);
239       int32_t Lo = Value & 0xFFF;
240       uint32_t RawInstrAuipc = *(little32_t *)FixupPtr;
241       uint32_t RawInstrJalr = *(little32_t *)(FixupPtr + 4);
242       *(little32_t *)FixupPtr =
243           RawInstrAuipc | (static_cast<uint32_t>(Hi & 0xFFFFF000));
244       *(little32_t *)(FixupPtr + 4) =
245           RawInstrJalr | (static_cast<uint32_t>(Lo) << 20);
246       break;
247     }
248     // The relocations R_RISCV_CALL_PLT and R_RISCV_GOT_HI20 are handled by
249     // PerGraphGOTAndPLTStubsBuilder_ELF_riscv and are transformed into
250     // R_RISCV_CALL and R_RISCV_PCREL_HI20.
251     case R_RISCV_PCREL_HI20: {
252       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
253       int64_t Hi = Value + 0x800;
254       if (LLVM_UNLIKELY(!isInRangeForImm(Hi, 32)))
255         return makeTargetOutOfRangeError(G, B, E);
256       uint32_t RawInstr = *(little32_t *)FixupPtr;
257       *(little32_t *)FixupPtr =
258           (RawInstr & 0xFFF) | (static_cast<uint32_t>(Hi & 0xFFFFF000));
259       break;
260     }
261     case R_RISCV_PCREL_LO12_I: {
262       // FIXME: We assume that R_RISCV_PCREL_HI20 is present in object code and
263       // pairs with current relocation R_RISCV_PCREL_LO12_I. So here may need a
264       // check.
265       auto RelHI20 = getRISCVPCRelHi20(E);
266       if (!RelHI20)
267         return RelHI20.takeError();
268       int64_t Value = RelHI20->getTarget().getAddress() +
269                       RelHI20->getAddend() - E.getTarget().getAddress();
270       int64_t Lo = Value & 0xFFF;
271       uint32_t RawInstr = *(little32_t *)FixupPtr;
272       *(little32_t *)FixupPtr =
273           (RawInstr & 0xFFFFF) | (static_cast<uint32_t>(Lo & 0xFFF) << 20);
274       break;
275     }
276     case R_RISCV_PCREL_LO12_S: {
277       // FIXME: We assume that R_RISCV_PCREL_HI20 is present in object code and
278       // pairs with current relocation R_RISCV_PCREL_LO12_S. So here may need a
279       // check.
280       auto RelHI20 = getRISCVPCRelHi20(E);
281       if (!RelHI20)
282         return RelHI20.takeError();
283       int64_t Value = RelHI20->getTarget().getAddress() +
284                       RelHI20->getAddend() - E.getTarget().getAddress();
285       int64_t Lo = Value & 0xFFF;
286       uint32_t Imm11_5 = extractBits(Lo, 5, 7) << 25;
287       uint32_t Imm4_0 = extractBits(Lo, 0, 5) << 7;
288       uint32_t RawInstr = *(little32_t *)FixupPtr;
289 
290       *(little32_t *)FixupPtr = (RawInstr & 0x1FFF07F) | Imm11_5 | Imm4_0;
291       break;
292     }
293     case R_RISCV_HI20: {
294       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
295       int64_t Hi = Value + 0x800;
296       if (LLVM_UNLIKELY(!isInRangeForImm(Hi, 32)))
297         return makeTargetOutOfRangeError(G, B, E);
298       uint32_t RawInstr = *(little32_t *)FixupPtr;
299       *(little32_t *)FixupPtr =
300           (RawInstr & 0xFFF) | (static_cast<uint32_t>(Hi & 0xFFFFF000));
301       break;
302     }
303     case R_RISCV_LO12_I: {
304       // FIXME: We assume that R_RISCV_HI20 is present in object code and pairs
305       // with current relocation R_RISCV_LO12_I. So here may need a check.
306       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
307       int32_t Lo = Value & 0xFFF;
308       uint32_t RawInstr = *(little32_t *)FixupPtr;
309       *(little32_t *)FixupPtr =
310           (RawInstr & 0xFFFFF) | (static_cast<uint32_t>(Lo & 0xFFF) << 20);
311       break;
312     }
313     case R_RISCV_LO12_S: {
314       // FIXME: We assume that R_RISCV_HI20 is present in object code and pairs
315       // with current relocation R_RISCV_LO12_S. So here may need a check.
316       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
317       int64_t Lo = Value & 0xFFF;
318       uint32_t Imm11_5 = extractBits(Lo, 5, 7) << 25;
319       uint32_t Imm4_0 = extractBits(Lo, 0, 5) << 7;
320       uint32_t RawInstr = *(little32_t *)FixupPtr;
321       *(little32_t *)FixupPtr = (RawInstr & 0x1FFF07F) | Imm11_5 | Imm4_0;
322       break;
323     }
324     case R_RISCV_ADD8: {
325       int64_t Value =
326           (E.getTarget().getAddress() +
327            *(reinterpret_cast<const uint8_t *>(FixupPtr)) + E.getAddend())
328               .getValue();
329       *FixupPtr = static_cast<uint8_t>(Value);
330       break;
331     }
332     case R_RISCV_ADD16: {
333       int64_t Value = (E.getTarget().getAddress() +
334                        support::endian::read16le(FixupPtr) + E.getAddend())
335                           .getValue();
336       *(little16_t *)FixupPtr = static_cast<uint16_t>(Value);
337       break;
338     }
339     case R_RISCV_ADD32: {
340       int64_t Value = (E.getTarget().getAddress() +
341                        support::endian::read32le(FixupPtr) + E.getAddend())
342                           .getValue();
343       *(little32_t *)FixupPtr = static_cast<uint32_t>(Value);
344       break;
345     }
346     case R_RISCV_ADD64: {
347       int64_t Value = (E.getTarget().getAddress() +
348                        support::endian::read64le(FixupPtr) + E.getAddend())
349                           .getValue();
350       *(little64_t *)FixupPtr = static_cast<uint64_t>(Value);
351       break;
352     }
353     case R_RISCV_SUB8: {
354       int64_t Value = *(reinterpret_cast<const uint8_t *>(FixupPtr)) -
355                       E.getTarget().getAddress().getValue() - E.getAddend();
356       *FixupPtr = static_cast<uint8_t>(Value);
357       break;
358     }
359     case R_RISCV_SUB16: {
360       int64_t Value = support::endian::read16le(FixupPtr) -
361                       E.getTarget().getAddress().getValue() - E.getAddend();
362       *(little16_t *)FixupPtr = static_cast<uint32_t>(Value);
363       break;
364     }
365     case R_RISCV_SUB32: {
366       int64_t Value = support::endian::read32le(FixupPtr) -
367                       E.getTarget().getAddress().getValue() - E.getAddend();
368       *(little32_t *)FixupPtr = static_cast<uint32_t>(Value);
369       break;
370     }
371     case R_RISCV_SUB64: {
372       int64_t Value = support::endian::read64le(FixupPtr) -
373                       E.getTarget().getAddress().getValue() - E.getAddend();
374       *(little64_t *)FixupPtr = static_cast<uint64_t>(Value);
375       break;
376     }
377     case R_RISCV_RVC_BRANCH: {
378       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
379       if (LLVM_UNLIKELY(!isInRangeForImm(Value >> 1, 8)))
380         return makeTargetOutOfRangeError(G, B, E);
381       if (LLVM_UNLIKELY(!isAlignmentCorrect(Value, 2)))
382         return makeAlignmentError(FixupAddress, Value, 2, E);
383       uint16_t Imm8 = extractBits(Value, 8, 1) << 12;
384       uint16_t Imm4_3 = extractBits(Value, 3, 2) << 10;
385       uint16_t Imm7_6 = extractBits(Value, 6, 2) << 5;
386       uint16_t Imm2_1 = extractBits(Value, 1, 2) << 3;
387       uint16_t Imm5 = extractBits(Value, 5, 1) << 2;
388       uint16_t RawInstr = *(little16_t *)FixupPtr;
389       *(little16_t *)FixupPtr =
390           (RawInstr & 0xE383) | Imm8 | Imm4_3 | Imm7_6 | Imm2_1 | Imm5;
391       break;
392     }
393     case R_RISCV_RVC_JUMP: {
394       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
395       if (LLVM_UNLIKELY(!isInRangeForImm(Value >> 1, 11)))
396         return makeTargetOutOfRangeError(G, B, E);
397       if (LLVM_UNLIKELY(!isAlignmentCorrect(Value, 2)))
398         return makeAlignmentError(FixupAddress, Value, 2, E);
399       uint16_t Imm11 = extractBits(Value, 11, 1) << 12;
400       uint16_t Imm4 = extractBits(Value, 4, 1) << 11;
401       uint16_t Imm9_8 = extractBits(Value, 8, 2) << 9;
402       uint16_t Imm10 = extractBits(Value, 10, 1) << 8;
403       uint16_t Imm6 = extractBits(Value, 6, 1) << 7;
404       uint16_t Imm7 = extractBits(Value, 7, 1) << 6;
405       uint16_t Imm3_1 = extractBits(Value, 1, 3) << 3;
406       uint16_t Imm5 = extractBits(Value, 5, 1) << 2;
407       uint16_t RawInstr = *(little16_t *)FixupPtr;
408       *(little16_t *)FixupPtr = (RawInstr & 0xE003) | Imm11 | Imm4 | Imm9_8 |
409                                 Imm10 | Imm6 | Imm7 | Imm3_1 | Imm5;
410       break;
411     }
412     case R_RISCV_SUB6: {
413       int64_t Value = *(reinterpret_cast<const uint8_t *>(FixupPtr)) & 0x3f;
414       Value -= E.getTarget().getAddress().getValue() - E.getAddend();
415       *FixupPtr = (*FixupPtr & 0xc0) | (static_cast<uint8_t>(Value) & 0x3f);
416       break;
417     }
418     case R_RISCV_SET6: {
419       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
420       uint32_t RawData = *(little32_t *)FixupPtr;
421       int64_t Word6 = Value & 0x3f;
422       *(little32_t *)FixupPtr = (RawData & 0xffffffc0) | Word6;
423       break;
424     }
425     case R_RISCV_SET8: {
426       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
427       uint32_t RawData = *(little32_t *)FixupPtr;
428       int64_t Word8 = Value & 0xff;
429       *(little32_t *)FixupPtr = (RawData & 0xffffff00) | Word8;
430       break;
431     }
432     case R_RISCV_SET16: {
433       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
434       uint32_t RawData = *(little32_t *)FixupPtr;
435       int64_t Word16 = Value & 0xffff;
436       *(little32_t *)FixupPtr = (RawData & 0xffff0000) | Word16;
437       break;
438     }
439     case R_RISCV_SET32: {
440       int64_t Value = (E.getTarget().getAddress() + E.getAddend()).getValue();
441       int64_t Word32 = Value & 0xffffffff;
442       *(little32_t *)FixupPtr = Word32;
443       break;
444     }
445     case R_RISCV_32_PCREL: {
446       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
447       int64_t Word32 = Value & 0xffffffff;
448       *(little32_t *)FixupPtr = Word32;
449       break;
450     }
451     }
452     return Error::success();
453   }
454 };
455 
456 template <typename ELFT>
457 class ELFLinkGraphBuilder_riscv : public ELFLinkGraphBuilder<ELFT> {
458 private:
459   static Expected<riscv::EdgeKind_riscv>
460   getRelocationKind(const uint32_t Type) {
461     using namespace riscv;
462     switch (Type) {
463     case ELF::R_RISCV_32:
464       return EdgeKind_riscv::R_RISCV_32;
465     case ELF::R_RISCV_64:
466       return EdgeKind_riscv::R_RISCV_64;
467     case ELF::R_RISCV_BRANCH:
468       return EdgeKind_riscv::R_RISCV_BRANCH;
469     case ELF::R_RISCV_JAL:
470       return EdgeKind_riscv::R_RISCV_JAL;
471     case ELF::R_RISCV_CALL:
472       return EdgeKind_riscv::R_RISCV_CALL;
473     case ELF::R_RISCV_CALL_PLT:
474       return EdgeKind_riscv::R_RISCV_CALL_PLT;
475     case ELF::R_RISCV_GOT_HI20:
476       return EdgeKind_riscv::R_RISCV_GOT_HI20;
477     case ELF::R_RISCV_PCREL_HI20:
478       return EdgeKind_riscv::R_RISCV_PCREL_HI20;
479     case ELF::R_RISCV_PCREL_LO12_I:
480       return EdgeKind_riscv::R_RISCV_PCREL_LO12_I;
481     case ELF::R_RISCV_PCREL_LO12_S:
482       return EdgeKind_riscv::R_RISCV_PCREL_LO12_S;
483     case ELF::R_RISCV_HI20:
484       return EdgeKind_riscv::R_RISCV_HI20;
485     case ELF::R_RISCV_LO12_I:
486       return EdgeKind_riscv::R_RISCV_LO12_I;
487     case ELF::R_RISCV_LO12_S:
488       return EdgeKind_riscv::R_RISCV_LO12_S;
489     case ELF::R_RISCV_ADD8:
490       return EdgeKind_riscv::R_RISCV_ADD8;
491     case ELF::R_RISCV_ADD16:
492       return EdgeKind_riscv::R_RISCV_ADD16;
493     case ELF::R_RISCV_ADD32:
494       return EdgeKind_riscv::R_RISCV_ADD32;
495     case ELF::R_RISCV_ADD64:
496       return EdgeKind_riscv::R_RISCV_ADD64;
497     case ELF::R_RISCV_SUB8:
498       return EdgeKind_riscv::R_RISCV_SUB8;
499     case ELF::R_RISCV_SUB16:
500       return EdgeKind_riscv::R_RISCV_SUB16;
501     case ELF::R_RISCV_SUB32:
502       return EdgeKind_riscv::R_RISCV_SUB32;
503     case ELF::R_RISCV_SUB64:
504       return EdgeKind_riscv::R_RISCV_SUB64;
505     case ELF::R_RISCV_RVC_BRANCH:
506       return EdgeKind_riscv::R_RISCV_RVC_BRANCH;
507     case ELF::R_RISCV_RVC_JUMP:
508       return EdgeKind_riscv::R_RISCV_RVC_JUMP;
509     case ELF::R_RISCV_SUB6:
510       return EdgeKind_riscv::R_RISCV_SUB6;
511     case ELF::R_RISCV_SET6:
512       return EdgeKind_riscv::R_RISCV_SET6;
513     case ELF::R_RISCV_SET8:
514       return EdgeKind_riscv::R_RISCV_SET8;
515     case ELF::R_RISCV_SET16:
516       return EdgeKind_riscv::R_RISCV_SET16;
517     case ELF::R_RISCV_SET32:
518       return EdgeKind_riscv::R_RISCV_SET32;
519     case ELF::R_RISCV_32_PCREL:
520       return EdgeKind_riscv::R_RISCV_32_PCREL;
521     }
522 
523     return make_error<JITLinkError>(
524         "Unsupported riscv relocation:" + formatv("{0:d}: ", Type) +
525         object::getELFRelocationTypeName(ELF::EM_RISCV, Type));
526   }
527 
528   Error addRelocations() override {
529     LLVM_DEBUG(dbgs() << "Processing relocations:\n");
530 
531     using Base = ELFLinkGraphBuilder<ELFT>;
532     using Self = ELFLinkGraphBuilder_riscv<ELFT>;
533     for (const auto &RelSect : Base::Sections)
534       if (Error Err = Base::forEachRelaRelocation(RelSect, this,
535                                                   &Self::addSingleRelocation))
536         return Err;
537 
538     return Error::success();
539   }
540 
541   Error addSingleRelocation(const typename ELFT::Rela &Rel,
542                             const typename ELFT::Shdr &FixupSect,
543                             Block &BlockToFix) {
544     using Base = ELFLinkGraphBuilder<ELFT>;
545 
546     uint32_t Type = Rel.getType(false);
547     // We do not implement linker relaxation, except what is required for
548     // alignment (see below).
549     if (Type == llvm::ELF::R_RISCV_RELAX)
550       return Error::success();
551 
552     int64_t Addend = Rel.r_addend;
553     if (Type == llvm::ELF::R_RISCV_ALIGN) {
554       uint64_t Alignment = PowerOf2Ceil(Addend);
555       // FIXME: Implement support for ensuring alignment together with linker
556       // relaxation; 2 bytes are guaranteed by the length of compressed
557       // instructions, so this does not need any action from our side.
558       if (Alignment > 2)
559         return make_error<JITLinkError>(
560             formatv("Unsupported relocation R_RISCV_ALIGN with alignment {0} "
561                     "larger than 2 (addend: {1})",
562                     Alignment, Addend));
563       return Error::success();
564     }
565 
566     Expected<riscv::EdgeKind_riscv> Kind = getRelocationKind(Type);
567     if (!Kind)
568       return Kind.takeError();
569 
570     uint32_t SymbolIndex = Rel.getSymbol(false);
571     auto ObjSymbol = Base::Obj.getRelocationSymbol(Rel, Base::SymTabSec);
572     if (!ObjSymbol)
573       return ObjSymbol.takeError();
574 
575     Symbol *GraphSymbol = Base::getGraphSymbol(SymbolIndex);
576     if (!GraphSymbol)
577       return make_error<StringError>(
578           formatv("Could not find symbol at given index, did you add it to "
579                   "JITSymbolTable? index: {0}, shndx: {1} Size of table: {2}",
580                   SymbolIndex, (*ObjSymbol)->st_shndx,
581                   Base::GraphSymbols.size()),
582           inconvertibleErrorCode());
583 
584     auto FixupAddress = orc::ExecutorAddr(FixupSect.sh_addr) + Rel.r_offset;
585     Edge::OffsetT Offset = FixupAddress - BlockToFix.getAddress();
586     Edge GE(*Kind, Offset, *GraphSymbol, Addend);
587     LLVM_DEBUG({
588       dbgs() << "    ";
589       printEdge(dbgs(), BlockToFix, GE, riscv::getEdgeKindName(*Kind));
590       dbgs() << "\n";
591     });
592 
593     BlockToFix.addEdge(std::move(GE));
594     return Error::success();
595   }
596 
597 public:
598   ELFLinkGraphBuilder_riscv(StringRef FileName,
599                             const object::ELFFile<ELFT> &Obj, Triple TT)
600       : ELFLinkGraphBuilder<ELFT>(Obj, std::move(TT), FileName,
601                                   riscv::getEdgeKindName) {}
602 };
603 
604 Expected<std::unique_ptr<LinkGraph>>
605 createLinkGraphFromELFObject_riscv(MemoryBufferRef ObjectBuffer) {
606   LLVM_DEBUG({
607     dbgs() << "Building jitlink graph for new input "
608            << ObjectBuffer.getBufferIdentifier() << "...\n";
609   });
610 
611   auto ELFObj = object::ObjectFile::createELFObjectFile(ObjectBuffer);
612   if (!ELFObj)
613     return ELFObj.takeError();
614 
615   if ((*ELFObj)->getArch() == Triple::riscv64) {
616     auto &ELFObjFile = cast<object::ELFObjectFile<object::ELF64LE>>(**ELFObj);
617     return ELFLinkGraphBuilder_riscv<object::ELF64LE>(
618                (*ELFObj)->getFileName(), ELFObjFile.getELFFile(),
619                (*ELFObj)->makeTriple())
620         .buildGraph();
621   } else {
622     assert((*ELFObj)->getArch() == Triple::riscv32 &&
623            "Invalid triple for RISCV ELF object file");
624     auto &ELFObjFile = cast<object::ELFObjectFile<object::ELF32LE>>(**ELFObj);
625     return ELFLinkGraphBuilder_riscv<object::ELF32LE>(
626                (*ELFObj)->getFileName(), ELFObjFile.getELFFile(),
627                (*ELFObj)->makeTriple())
628         .buildGraph();
629   }
630 }
631 
632 void link_ELF_riscv(std::unique_ptr<LinkGraph> G,
633                     std::unique_ptr<JITLinkContext> Ctx) {
634   PassConfiguration Config;
635   const Triple &TT = G->getTargetTriple();
636   if (Ctx->shouldAddDefaultTargetPasses(TT)) {
637     if (auto MarkLive = Ctx->getMarkLivePass(TT))
638       Config.PrePrunePasses.push_back(std::move(MarkLive));
639     else
640       Config.PrePrunePasses.push_back(markAllSymbolsLive);
641     Config.PostPrunePasses.push_back(
642         PerGraphGOTAndPLTStubsBuilder_ELF_riscv::asPass);
643   }
644   if (auto Err = Ctx->modifyPassConfig(*G, Config))
645     return Ctx->notifyFailed(std::move(Err));
646 
647   ELFJITLinker_riscv::link(std::move(Ctx), std::move(G), std::move(Config));
648 }
649 
650 } // namespace jitlink
651 } // namespace llvm
652