1 | //===--- ppc64.h - Generic JITLink ppc64 edge kinds, utilities --*- 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 | // Generic utilities for graphs representing 64-bit PowerPC objects. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_EXECUTIONENGINE_JITLINK_PPC64_H |
14 | #define LLVM_EXECUTIONENGINE_JITLINK_PPC64_H |
15 | |
16 | #include "llvm/ExecutionEngine/JITLink/JITLink.h" |
17 | #include "llvm/ExecutionEngine/JITLink/TableManager.h" |
18 | #include "llvm/Support/Endian.h" |
19 | |
20 | namespace llvm::jitlink::ppc64 { |
21 | |
22 | /// Represents ppc64 fixups and other ppc64-specific edge kinds. |
23 | enum EdgeKind_ppc64 : Edge::Kind { |
24 | Pointer64 = Edge::FirstRelocation, |
25 | Pointer32, |
26 | Pointer16, |
27 | Pointer16DS, |
28 | Pointer16HA, |
29 | Pointer16HI, |
30 | Pointer16HIGH, |
31 | Pointer16HIGHA, |
32 | Pointer16HIGHER, |
33 | Pointer16HIGHERA, |
34 | Pointer16HIGHEST, |
35 | Pointer16HIGHESTA, |
36 | Pointer16LO, |
37 | Pointer16LODS, |
38 | Pointer14, |
39 | Delta64, |
40 | Delta34, |
41 | Delta32, |
42 | NegDelta32, |
43 | Delta16, |
44 | Delta16HA, |
45 | Delta16HI, |
46 | Delta16LO, |
47 | TOC, |
48 | TOCDelta16, |
49 | TOCDelta16DS, |
50 | TOCDelta16HA, |
51 | TOCDelta16HI, |
52 | TOCDelta16LO, |
53 | TOCDelta16LODS, |
54 | RequestGOTAndTransformToDelta34, |
55 | CallBranchDelta, |
56 | // Need to restore r2 after the bl, suggesting the bl is followed by a nop. |
57 | CallBranchDeltaRestoreTOC, |
58 | // Request calling function with TOC. |
59 | RequestCall, |
60 | // Request calling function without TOC. |
61 | RequestCallNoTOC, |
62 | RequestTLSDescInGOTAndTransformToTOCDelta16HA, |
63 | RequestTLSDescInGOTAndTransformToTOCDelta16LO, |
64 | RequestTLSDescInGOTAndTransformToDelta34, |
65 | }; |
66 | |
67 | enum PLTCallStubKind { |
68 | // Setup function entry(r12) and long branch to target using TOC. |
69 | LongBranch, |
70 | // Save TOC pointer, setup function entry and long branch to target using TOC. |
71 | LongBranchSaveR2, |
72 | // Setup function entry(r12) and long branch to target without using TOC. |
73 | LongBranchNoTOC, |
74 | }; |
75 | |
76 | extern const char NullPointerContent[8]; |
77 | extern const char PointerJumpStubContent_big[20]; |
78 | extern const char PointerJumpStubContent_little[20]; |
79 | extern const char PointerJumpStubNoTOCContent_big[32]; |
80 | extern const char PointerJumpStubNoTOCContent_little[32]; |
81 | |
82 | struct PLTCallStubReloc { |
83 | Edge::Kind K; |
84 | size_t Offset; |
85 | Edge::AddendT A; |
86 | }; |
87 | |
88 | struct PLTCallStubInfo { |
89 | ArrayRef<char> Content; |
90 | SmallVector<PLTCallStubReloc, 2> Relocs; |
91 | }; |
92 | |
93 | template <llvm::endianness Endianness> |
94 | inline PLTCallStubInfo pickStub(PLTCallStubKind StubKind) { |
95 | constexpr bool isLE = Endianness == llvm::endianness::little; |
96 | switch (StubKind) { |
97 | case LongBranch: { |
98 | ArrayRef<char> Content = |
99 | isLE ? PointerJumpStubContent_little : PointerJumpStubContent_big; |
100 | // Skip save r2. |
101 | Content = Content.slice(N: 4); |
102 | size_t Offset = isLE ? 0 : 2; |
103 | return PLTCallStubInfo{ |
104 | .Content: Content, |
105 | .Relocs: {{.K: TOCDelta16HA, .Offset: Offset, .A: 0}, {.K: TOCDelta16LO, .Offset: Offset + 4, .A: 0}}, |
106 | }; |
107 | } |
108 | case LongBranchSaveR2: { |
109 | ArrayRef<char> Content = |
110 | isLE ? PointerJumpStubContent_little : PointerJumpStubContent_big; |
111 | size_t Offset = isLE ? 4 : 6; |
112 | return PLTCallStubInfo{ |
113 | .Content: Content, |
114 | .Relocs: {{.K: TOCDelta16HA, .Offset: Offset, .A: 0}, {.K: TOCDelta16LO, .Offset: Offset + 4, .A: 0}}, |
115 | }; |
116 | } |
117 | case LongBranchNoTOC: { |
118 | ArrayRef<char> Content = isLE ? PointerJumpStubNoTOCContent_little |
119 | : PointerJumpStubNoTOCContent_big; |
120 | size_t Offset = isLE ? 16 : 18; |
121 | Edge::AddendT Addend = isLE ? 8 : 10; |
122 | return PLTCallStubInfo{ |
123 | .Content: Content, |
124 | .Relocs: {{.K: Delta16HA, .Offset: Offset, .A: Addend}, {.K: Delta16LO, .Offset: Offset + 4, .A: Addend + 4}}, |
125 | }; |
126 | } |
127 | } |
128 | llvm_unreachable("Unknown PLTCallStubKind enum" ); |
129 | } |
130 | |
131 | inline Symbol &createAnonymousPointer(LinkGraph &G, Section &PointerSection, |
132 | Symbol *InitialTarget = nullptr, |
133 | uint64_t InitialAddend = 0) { |
134 | assert(G.getPointerSize() == sizeof(NullPointerContent) && |
135 | "LinkGraph's pointer size should be consistent with size of " |
136 | "NullPointerContent" ); |
137 | Block &B = G.createContentBlock(Parent&: PointerSection, Content: NullPointerContent, |
138 | Address: orc::ExecutorAddr(), Alignment: G.getPointerSize(), AlignmentOffset: 0); |
139 | if (InitialTarget) |
140 | B.addEdge(K: Pointer64, Offset: 0, Target&: *InitialTarget, Addend: InitialAddend); |
141 | return G.addAnonymousSymbol(Content&: B, Offset: 0, Size: G.getPointerSize(), IsCallable: false, IsLive: false); |
142 | } |
143 | |
144 | template <llvm::endianness Endianness> |
145 | inline Symbol &createAnonymousPointerJumpStub(LinkGraph &G, |
146 | Section &StubSection, |
147 | Symbol &PointerSymbol, |
148 | PLTCallStubKind StubKind) { |
149 | PLTCallStubInfo StubInfo = pickStub<Endianness>(StubKind); |
150 | Block &B = G.createContentBlock(Parent&: StubSection, Content: StubInfo.Content, |
151 | Address: orc::ExecutorAddr(), Alignment: 4, AlignmentOffset: 0); |
152 | for (auto const &Reloc : StubInfo.Relocs) |
153 | B.addEdge(K: Reloc.K, Offset: Reloc.Offset, Target&: PointerSymbol, Addend: Reloc.A); |
154 | return G.addAnonymousSymbol(Content&: B, Offset: 0, Size: StubInfo.Content.size(), IsCallable: true, IsLive: false); |
155 | } |
156 | |
157 | template <llvm::endianness Endianness> |
158 | class TOCTableManager : public TableManager<TOCTableManager<Endianness>> { |
159 | public: |
160 | // FIXME: `llvm-jitlink -check` relies this name to be $__GOT. |
161 | static StringRef getSectionName() { return "$__GOT" ; } |
162 | |
163 | bool visitEdge(LinkGraph &G, Block *B, Edge &E) { |
164 | Edge::Kind K = E.getKind(); |
165 | switch (K) { |
166 | case TOCDelta16HA: |
167 | case TOCDelta16LO: |
168 | case TOCDelta16DS: |
169 | case TOCDelta16LODS: |
170 | case CallBranchDeltaRestoreTOC: |
171 | case RequestCall: |
172 | // Create TOC section if TOC relocation, PLT or GOT is used. |
173 | getOrCreateTOCSection(G); |
174 | return false; |
175 | case RequestGOTAndTransformToDelta34: |
176 | E.setKind(ppc64::Delta34); |
177 | E.setTarget(createEntry(G, Target&: E.getTarget())); |
178 | return true; |
179 | default: |
180 | return false; |
181 | } |
182 | } |
183 | |
184 | Symbol &createEntry(LinkGraph &G, Symbol &Target) { |
185 | return createAnonymousPointer(G, getOrCreateTOCSection(G), &Target); |
186 | } |
187 | |
188 | private: |
189 | Section &getOrCreateTOCSection(LinkGraph &G) { |
190 | TOCSection = G.findSectionByName(Name: getSectionName()); |
191 | if (!TOCSection) |
192 | TOCSection = &G.createSection(Name: getSectionName(), Prot: orc::MemProt::Read); |
193 | return *TOCSection; |
194 | } |
195 | |
196 | Section *TOCSection = nullptr; |
197 | }; |
198 | |
199 | template <llvm::endianness Endianness> |
200 | class PLTTableManager : public TableManager<PLTTableManager<Endianness>> { |
201 | public: |
202 | PLTTableManager(TOCTableManager<Endianness> &TOC) : TOC(TOC) {} |
203 | |
204 | static StringRef getSectionName() { return "$__STUBS" ; } |
205 | |
206 | // FIXME: One external symbol can only have one PLT stub in a object file. |
207 | // This is a limitation when we need different PLT stubs for the same symbol. |
208 | // For example, we need two different PLT stubs for `bl __tls_get_addr` and |
209 | // `bl __tls_get_addr@notoc`. |
210 | bool visitEdge(LinkGraph &G, Block *B, Edge &E) { |
211 | bool isExternal = E.getTarget().isExternal(); |
212 | Edge::Kind K = E.getKind(); |
213 | if (K == ppc64::RequestCall) { |
214 | if (isExternal) { |
215 | E.setKind(ppc64::CallBranchDeltaRestoreTOC); |
216 | this->StubKind = LongBranchSaveR2; |
217 | // FIXME: We assume the addend to the external target is zero. It's |
218 | // quite unusual that the addend of an external target to be non-zero as |
219 | // if we have known the layout of the external object. |
220 | E.setTarget(this->getEntryForTarget(G, E.getTarget())); |
221 | // Addend to the stub is zero. |
222 | E.setAddend(0); |
223 | } else |
224 | // TODO: There are cases a local function call need a call stub. |
225 | // 1. Caller uses TOC, the callee doesn't, need a r2 save stub. |
226 | // 2. Caller doesn't use TOC, the callee does, need a r12 setup stub. |
227 | // 3. Branching target is out of range. |
228 | E.setKind(ppc64::CallBranchDelta); |
229 | return true; |
230 | } |
231 | if (K == ppc64::RequestCallNoTOC) { |
232 | E.setKind(ppc64::CallBranchDelta); |
233 | this->StubKind = LongBranchNoTOC; |
234 | E.setTarget(this->getEntryForTarget(G, E.getTarget())); |
235 | return true; |
236 | } |
237 | return false; |
238 | } |
239 | |
240 | Symbol &createEntry(LinkGraph &G, Symbol &Target) { |
241 | return createAnonymousPointerJumpStub<Endianness>( |
242 | G, getOrCreateStubsSection(G), TOC.getEntryForTarget(G, Target), |
243 | this->StubKind); |
244 | } |
245 | |
246 | private: |
247 | Section &getOrCreateStubsSection(LinkGraph &G) { |
248 | PLTSection = G.findSectionByName(Name: getSectionName()); |
249 | if (!PLTSection) |
250 | PLTSection = &G.createSection(Name: getSectionName(), |
251 | Prot: orc::MemProt::Read | orc::MemProt::Exec); |
252 | return *PLTSection; |
253 | } |
254 | |
255 | TOCTableManager<Endianness> &TOC; |
256 | Section *PLTSection = nullptr; |
257 | PLTCallStubKind StubKind; |
258 | }; |
259 | |
260 | /// Returns a string name for the given ppc64 edge. For debugging purposes |
261 | /// only. |
262 | const char *getEdgeKindName(Edge::Kind K); |
263 | |
264 | inline static uint16_t ha(uint64_t x) { return (x + 0x8000) >> 16; } |
265 | inline static uint64_t lo(uint64_t x) { return x & 0xffff; } |
266 | inline static uint16_t hi(uint64_t x) { return x >> 16; } |
267 | inline static uint64_t high(uint64_t x) { return (x >> 16) & 0xffff; } |
268 | inline static uint64_t higha(uint64_t x) { |
269 | return ((x + 0x8000) >> 16) & 0xffff; |
270 | } |
271 | inline static uint64_t higher(uint64_t x) { return (x >> 32) & 0xffff; } |
272 | inline static uint64_t highera(uint64_t x) { |
273 | return ((x + 0x8000) >> 32) & 0xffff; |
274 | } |
275 | inline static uint16_t highest(uint64_t x) { return x >> 48; } |
276 | inline static uint16_t highesta(uint64_t x) { return (x + 0x8000) >> 48; } |
277 | |
278 | // Prefixed instruction introduced in ISAv3.1 consists of two 32-bit words, |
279 | // prefix word and suffix word, i.e., prefixed_instruction = concat(prefix_word, |
280 | // suffix_word). That's to say, for a prefixed instruction encoded in uint64_t, |
281 | // the most significant 32 bits belong to the prefix word. The prefix word is at |
282 | // low address for both big/little endian. Byte order in each word still follows |
283 | // its endian. |
284 | template <llvm::endianness Endianness> |
285 | inline static uint64_t readPrefixedInstruction(const char *Loc) { |
286 | constexpr bool isLE = Endianness == llvm::endianness::little; |
287 | uint64_t Inst = support::endian::read64<Endianness>(Loc); |
288 | return isLE ? (Inst << 32) | (Inst >> 32) : Inst; |
289 | } |
290 | |
291 | template <llvm::endianness Endianness> |
292 | inline static void writePrefixedInstruction(char *Loc, uint64_t Inst) { |
293 | constexpr bool isLE = Endianness == llvm::endianness::little; |
294 | Inst = isLE ? (Inst << 32) | (Inst >> 32) : Inst; |
295 | support::endian::write64<Endianness>(Loc, Inst); |
296 | } |
297 | |
298 | template <llvm::endianness Endianness> |
299 | inline Error relocateHalf16(char *FixupPtr, int64_t Value, Edge::Kind K) { |
300 | switch (K) { |
301 | case Delta16: |
302 | case Pointer16: |
303 | case TOCDelta16: |
304 | support::endian::write16<Endianness>(FixupPtr, Value); |
305 | break; |
306 | case Pointer16DS: |
307 | case TOCDelta16DS: |
308 | support::endian::write16<Endianness>(FixupPtr, Value & ~3); |
309 | break; |
310 | case Delta16HA: |
311 | case Pointer16HA: |
312 | case TOCDelta16HA: |
313 | support::endian::write16<Endianness>(FixupPtr, ha(x: Value)); |
314 | break; |
315 | case Delta16HI: |
316 | case Pointer16HI: |
317 | case TOCDelta16HI: |
318 | support::endian::write16<Endianness>(FixupPtr, hi(x: Value)); |
319 | break; |
320 | case Pointer16HIGH: |
321 | support::endian::write16<Endianness>(FixupPtr, high(x: Value)); |
322 | break; |
323 | case Pointer16HIGHA: |
324 | support::endian::write16<Endianness>(FixupPtr, higha(x: Value)); |
325 | break; |
326 | case Pointer16HIGHER: |
327 | support::endian::write16<Endianness>(FixupPtr, higher(x: Value)); |
328 | break; |
329 | case Pointer16HIGHERA: |
330 | support::endian::write16<Endianness>(FixupPtr, highera(x: Value)); |
331 | break; |
332 | case Pointer16HIGHEST: |
333 | support::endian::write16<Endianness>(FixupPtr, highest(x: Value)); |
334 | break; |
335 | case Pointer16HIGHESTA: |
336 | support::endian::write16<Endianness>(FixupPtr, highesta(x: Value)); |
337 | break; |
338 | case Delta16LO: |
339 | case Pointer16LO: |
340 | case TOCDelta16LO: |
341 | support::endian::write16<Endianness>(FixupPtr, lo(x: Value)); |
342 | break; |
343 | case Pointer16LODS: |
344 | case TOCDelta16LODS: |
345 | support::endian::write16<Endianness>(FixupPtr, lo(x: Value) & ~3); |
346 | break; |
347 | default: |
348 | return make_error<JITLinkError>( |
349 | Args: StringRef(getEdgeKindName(K)) + |
350 | " relocation does not write at half16 field" ); |
351 | } |
352 | return Error::success(); |
353 | } |
354 | |
355 | /// Apply fixup expression for edge to block content. |
356 | template <llvm::endianness Endianness> |
357 | inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E, |
358 | const Symbol *TOCSymbol) { |
359 | char *BlockWorkingMem = B.getAlreadyMutableContent().data(); |
360 | char *FixupPtr = BlockWorkingMem + E.getOffset(); |
361 | orc::ExecutorAddr FixupAddress = B.getAddress() + E.getOffset(); |
362 | int64_t S = E.getTarget().getAddress().getValue(); |
363 | int64_t A = E.getAddend(); |
364 | int64_t P = FixupAddress.getValue(); |
365 | int64_t TOCBase = TOCSymbol ? TOCSymbol->getAddress().getValue() : 0; |
366 | Edge::Kind K = E.getKind(); |
367 | |
368 | DEBUG_WITH_TYPE("jitlink" , { |
369 | dbgs() << " Applying fixup on " << G.getEdgeKindName(K) |
370 | << " edge, (S, A, P, .TOC.) = (" << formatv("{0:x}" , S) << ", " |
371 | << formatv("{0:x}" , A) << ", " << formatv("{0:x}" , P) << ", " |
372 | << formatv("{0:x}" , TOCBase) << ")\n" ; |
373 | }); |
374 | |
375 | switch (K) { |
376 | case Pointer64: { |
377 | uint64_t Value = S + A; |
378 | support::endian::write64<Endianness>(FixupPtr, Value); |
379 | break; |
380 | } |
381 | case Delta16: |
382 | case Delta16HA: |
383 | case Delta16HI: |
384 | case Delta16LO: { |
385 | int64_t Value = S + A - P; |
386 | if (LLVM_UNLIKELY(!isInt<32>(Value))) { |
387 | return makeTargetOutOfRangeError(G, B, E); |
388 | } |
389 | return relocateHalf16<Endianness>(FixupPtr, Value, K); |
390 | } |
391 | case TOC: |
392 | support::endian::write64<Endianness>(FixupPtr, TOCBase); |
393 | break; |
394 | case Pointer16: |
395 | case Pointer16DS: |
396 | case Pointer16HA: |
397 | case Pointer16HI: |
398 | case Pointer16HIGH: |
399 | case Pointer16HIGHA: |
400 | case Pointer16HIGHER: |
401 | case Pointer16HIGHERA: |
402 | case Pointer16HIGHEST: |
403 | case Pointer16HIGHESTA: |
404 | case Pointer16LO: |
405 | case Pointer16LODS: { |
406 | uint64_t Value = S + A; |
407 | if (LLVM_UNLIKELY(!isInt<32>(Value))) { |
408 | return makeTargetOutOfRangeError(G, B, E); |
409 | } |
410 | return relocateHalf16<Endianness>(FixupPtr, Value, K); |
411 | } |
412 | case Pointer14: { |
413 | static const uint32_t Low14Mask = 0xfffc; |
414 | uint64_t Value = S + A; |
415 | assert((Value & 3) == 0 && "Pointer14 requires 4-byte alignment" ); |
416 | if (LLVM_UNLIKELY(!isInt<16>(Value))) { |
417 | return makeTargetOutOfRangeError(G, B, E); |
418 | } |
419 | uint32_t Inst = support::endian::read32<Endianness>(FixupPtr); |
420 | support::endian::write32<Endianness>(FixupPtr, (Inst & ~Low14Mask) | |
421 | (Value & Low14Mask)); |
422 | break; |
423 | } |
424 | case TOCDelta16: |
425 | case TOCDelta16DS: |
426 | case TOCDelta16HA: |
427 | case TOCDelta16HI: |
428 | case TOCDelta16LO: |
429 | case TOCDelta16LODS: { |
430 | int64_t Value = S + A - TOCBase; |
431 | if (LLVM_UNLIKELY(!isInt<32>(Value))) { |
432 | return makeTargetOutOfRangeError(G, B, E); |
433 | } |
434 | return relocateHalf16<Endianness>(FixupPtr, Value, K); |
435 | } |
436 | case CallBranchDeltaRestoreTOC: |
437 | case CallBranchDelta: { |
438 | int64_t Value = S + A - P; |
439 | if (LLVM_UNLIKELY(!isInt<26>(Value))) { |
440 | return makeTargetOutOfRangeError(G, B, E); |
441 | } |
442 | uint32_t Inst = support::endian::read32<Endianness>(FixupPtr); |
443 | support::endian::write32<Endianness>(FixupPtr, (Inst & 0xfc000003) | |
444 | (Value & 0x03fffffc)); |
445 | if (K == CallBranchDeltaRestoreTOC) { |
446 | uint32_t NopInst = support::endian::read32<Endianness>(FixupPtr + 4); |
447 | assert(NopInst == 0x60000000 && |
448 | "NOP should be placed here for restoring r2" ); |
449 | (void)NopInst; |
450 | // Restore r2 by instruction 0xe8410018 which is `ld r2, 24(r1)`. |
451 | support::endian::write32<Endianness>(FixupPtr + 4, 0xe8410018); |
452 | } |
453 | break; |
454 | } |
455 | case Delta64: { |
456 | int64_t Value = S + A - P; |
457 | support::endian::write64<Endianness>(FixupPtr, Value); |
458 | break; |
459 | } |
460 | case Delta34: { |
461 | int64_t Value = S + A - P; |
462 | if (!LLVM_UNLIKELY(isInt<34>(Value))) |
463 | return makeTargetOutOfRangeError(G, B, E); |
464 | static const uint64_t SI0Mask = 0x00000003ffff0000; |
465 | static const uint64_t SI1Mask = 0x000000000000ffff; |
466 | static const uint64_t FullMask = 0x0003ffff0000ffff; |
467 | uint64_t Inst = readPrefixedInstruction<Endianness>(FixupPtr) & ~FullMask; |
468 | writePrefixedInstruction<Endianness>( |
469 | FixupPtr, Inst | ((Value & SI0Mask) << 16) | (Value & SI1Mask)); |
470 | break; |
471 | } |
472 | case Delta32: { |
473 | int64_t Value = S + A - P; |
474 | if (LLVM_UNLIKELY(!isInt<32>(Value))) { |
475 | return makeTargetOutOfRangeError(G, B, E); |
476 | } |
477 | support::endian::write32<Endianness>(FixupPtr, Value); |
478 | break; |
479 | } |
480 | case NegDelta32: { |
481 | int64_t Value = P - S + A; |
482 | if (LLVM_UNLIKELY(!isInt<32>(Value))) { |
483 | return makeTargetOutOfRangeError(G, B, E); |
484 | } |
485 | support::endian::write32<Endianness>(FixupPtr, Value); |
486 | break; |
487 | } |
488 | default: |
489 | return make_error<JITLinkError>( |
490 | Args: "In graph " + G.getName() + ", section " + B.getSection().getName() + |
491 | " unsupported edge kind " + getEdgeKindName(K: E.getKind())); |
492 | } |
493 | return Error::success(); |
494 | } |
495 | |
496 | } // end namespace llvm::jitlink::ppc64 |
497 | |
498 | #endif // LLVM_EXECUTIONENGINE_JITLINK_PPC64_H |
499 | |