1 | //===- Chunks.h -------------------------------------------------*- 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 | #ifndef LLD_COFF_CHUNKS_H |
10 | #define LLD_COFF_CHUNKS_H |
11 | |
12 | #include "Config.h" |
13 | #include "InputFiles.h" |
14 | #include "lld/Common/LLVM.h" |
15 | #include "llvm/ADT/ArrayRef.h" |
16 | #include "llvm/ADT/PointerIntPair.h" |
17 | #include "llvm/ADT/iterator.h" |
18 | #include "llvm/ADT/iterator_range.h" |
19 | #include "llvm/MC/StringTableBuilder.h" |
20 | #include "llvm/Object/COFF.h" |
21 | #include <utility> |
22 | #include <vector> |
23 | |
24 | namespace lld::coff { |
25 | |
26 | using llvm::COFF::ImportDirectoryTableEntry; |
27 | using llvm::object::COFFSymbolRef; |
28 | using llvm::object::SectionRef; |
29 | using llvm::object::coff_relocation; |
30 | using llvm::object::coff_section; |
31 | |
32 | class Baserel; |
33 | class Defined; |
34 | class DefinedImportData; |
35 | class DefinedRegular; |
36 | class ObjFile; |
37 | class OutputSection; |
38 | class RuntimePseudoReloc; |
39 | class Symbol; |
40 | |
41 | // Mask for permissions (discardable, writable, readable, executable, etc). |
42 | const uint32_t permMask = 0xFE000000; |
43 | |
44 | // Mask for section types (code, data, bss). |
45 | const uint32_t typeMask = 0x000000E0; |
46 | |
47 | // The log base 2 of the largest section alignment, which is log2(8192), or 13. |
48 | enum : unsigned { Log2MaxSectionAlignment = 13 }; |
49 | |
50 | // A Chunk represents a chunk of data that will occupy space in the |
51 | // output (if the resolver chose that). It may or may not be backed by |
52 | // a section of an input file. It could be linker-created data, or |
53 | // doesn't even have actual data (if common or bss). |
54 | class Chunk { |
55 | public: |
56 | enum Kind : uint8_t { SectionKind, OtherKind, ImportThunkKind }; |
57 | Kind kind() const { return chunkKind; } |
58 | |
59 | // Returns the size of this chunk (even if this is a common or BSS.) |
60 | size_t getSize() const; |
61 | |
62 | // Returns chunk alignment in power of two form. Value values are powers of |
63 | // two from 1 to 8192. |
64 | uint32_t getAlignment() const { return 1U << p2Align; } |
65 | |
66 | // Update the chunk section alignment measured in bytes. Internally alignment |
67 | // is stored in log2. |
68 | void setAlignment(uint32_t align) { |
69 | // Treat zero byte alignment as 1 byte alignment. |
70 | align = align ? align : 1; |
71 | assert(llvm::isPowerOf2_32(align) && "alignment is not a power of 2" ); |
72 | p2Align = llvm::Log2_32(Value: align); |
73 | assert(p2Align <= Log2MaxSectionAlignment && |
74 | "impossible requested alignment" ); |
75 | } |
76 | |
77 | // Write this chunk to a mmap'ed file, assuming Buf is pointing to |
78 | // beginning of the file. Because this function may use RVA values |
79 | // of other chunks for relocations, you need to set them properly |
80 | // before calling this function. |
81 | void writeTo(uint8_t *buf) const; |
82 | |
83 | // The writer sets and uses the addresses. In practice, PE images cannot be |
84 | // larger than 2GB. Chunks are always laid as part of the image, so Chunk RVAs |
85 | // can be stored with 32 bits. |
86 | uint32_t getRVA() const { return rva; } |
87 | void setRVA(uint64_t v) { |
88 | // This may truncate. The writer checks for overflow later. |
89 | rva = (uint32_t)v; |
90 | } |
91 | |
92 | // Returns readable/writable/executable bits. |
93 | uint32_t getOutputCharacteristics() const; |
94 | |
95 | // Returns the section name if this is a section chunk. |
96 | // It is illegal to call this function on non-section chunks. |
97 | StringRef getSectionName() const; |
98 | |
99 | // An output section has pointers to chunks in the section, and each |
100 | // chunk has a back pointer to an output section. |
101 | void setOutputSectionIdx(uint16_t o) { osidx = o; } |
102 | uint16_t getOutputSectionIdx() const { return osidx; } |
103 | |
104 | // Windows-specific. |
105 | // Collect all locations that contain absolute addresses for base relocations. |
106 | void getBaserels(std::vector<Baserel> *res); |
107 | |
108 | // Returns a human-readable name of this chunk. Chunks are unnamed chunks of |
109 | // bytes, so this is used only for logging or debugging. |
110 | StringRef getDebugName() const; |
111 | |
112 | // Return true if this file has the hotpatch flag set to true in the |
113 | // S_COMPILE3 record in codeview debug info. Also returns true for some thunks |
114 | // synthesized by the linker. |
115 | bool isHotPatchable() const; |
116 | |
117 | protected: |
118 | Chunk(Kind k = OtherKind) : chunkKind(k), hasData(true), p2Align(0) {} |
119 | |
120 | const Kind chunkKind; |
121 | |
122 | public: |
123 | // Returns true if this has non-zero data. BSS chunks return |
124 | // false. If false is returned, the space occupied by this chunk |
125 | // will be filled with zeros. Corresponds to the |
126 | // IMAGE_SCN_CNT_UNINITIALIZED_DATA section characteristic bit. |
127 | uint8_t hasData : 1; |
128 | |
129 | public: |
130 | // The alignment of this chunk, stored in log2 form. The writer uses the |
131 | // value. |
132 | uint8_t p2Align : 7; |
133 | |
134 | // The output section index for this chunk. The first valid section number is |
135 | // one. |
136 | uint16_t osidx = 0; |
137 | |
138 | // The RVA of this chunk in the output. The writer sets a value. |
139 | uint32_t rva = 0; |
140 | }; |
141 | |
142 | class NonSectionChunk : public Chunk { |
143 | public: |
144 | virtual ~NonSectionChunk() = default; |
145 | |
146 | // Returns the size of this chunk (even if this is a common or BSS.) |
147 | virtual size_t getSize() const = 0; |
148 | |
149 | virtual uint32_t getOutputCharacteristics() const { return 0; } |
150 | |
151 | // Write this chunk to a mmap'ed file, assuming Buf is pointing to |
152 | // beginning of the file. Because this function may use RVA values |
153 | // of other chunks for relocations, you need to set them properly |
154 | // before calling this function. |
155 | virtual void writeTo(uint8_t *buf) const {} |
156 | |
157 | // Returns the section name if this is a section chunk. |
158 | // It is illegal to call this function on non-section chunks. |
159 | virtual StringRef getSectionName() const { |
160 | llvm_unreachable("unimplemented getSectionName" ); |
161 | } |
162 | |
163 | // Windows-specific. |
164 | // Collect all locations that contain absolute addresses for base relocations. |
165 | virtual void getBaserels(std::vector<Baserel> *res) {} |
166 | |
167 | // Returns a human-readable name of this chunk. Chunks are unnamed chunks of |
168 | // bytes, so this is used only for logging or debugging. |
169 | virtual StringRef getDebugName() const { return "" ; } |
170 | |
171 | static bool classof(const Chunk *c) { return c->kind() != SectionKind; } |
172 | |
173 | protected: |
174 | NonSectionChunk(Kind k = OtherKind) : Chunk(k) {} |
175 | }; |
176 | |
177 | // MinGW specific; information about one individual location in the image |
178 | // that needs to be fixed up at runtime after loading. This represents |
179 | // one individual element in the PseudoRelocTableChunk table. |
180 | class RuntimePseudoReloc { |
181 | public: |
182 | RuntimePseudoReloc(Defined *sym, SectionChunk *target, uint32_t targetOffset, |
183 | int flags) |
184 | : sym(sym), target(target), targetOffset(targetOffset), flags(flags) {} |
185 | |
186 | Defined *sym; |
187 | SectionChunk *target; |
188 | uint32_t targetOffset; |
189 | // The Flags field contains the size of the relocation, in bits. No other |
190 | // flags are currently defined. |
191 | int flags; |
192 | }; |
193 | |
194 | // A chunk corresponding a section of an input file. |
195 | class SectionChunk final : public Chunk { |
196 | // Identical COMDAT Folding feature accesses section internal data. |
197 | friend class ICF; |
198 | |
199 | public: |
200 | class symbol_iterator : public llvm::iterator_adaptor_base< |
201 | symbol_iterator, const coff_relocation *, |
202 | std::random_access_iterator_tag, Symbol *> { |
203 | friend SectionChunk; |
204 | |
205 | ObjFile *file; |
206 | |
207 | symbol_iterator(ObjFile *file, const coff_relocation *i) |
208 | : symbol_iterator::iterator_adaptor_base(i), file(file) {} |
209 | |
210 | public: |
211 | symbol_iterator() = default; |
212 | |
213 | Symbol *operator*() const { return file->getSymbol(symbolIndex: I->SymbolTableIndex); } |
214 | }; |
215 | |
216 | SectionChunk(ObjFile *file, const coff_section *); |
217 | static bool classof(const Chunk *c) { return c->kind() == SectionKind; } |
218 | size_t getSize() const { return header->SizeOfRawData; } |
219 | ArrayRef<uint8_t> getContents() const; |
220 | void writeTo(uint8_t *buf) const; |
221 | |
222 | // Defend against unsorted relocations. This may be overly conservative. |
223 | void sortRelocations(); |
224 | |
225 | // Write and relocate a portion of the section. This is intended to be called |
226 | // in a loop. Relocations must be sorted first. |
227 | void writeAndRelocateSubsection(ArrayRef<uint8_t> sec, |
228 | ArrayRef<uint8_t> subsec, |
229 | uint32_t &nextRelocIndex, uint8_t *buf) const; |
230 | |
231 | uint32_t getOutputCharacteristics() const { |
232 | return header->Characteristics & (permMask | typeMask); |
233 | } |
234 | StringRef getSectionName() const { |
235 | return StringRef(sectionNameData, sectionNameSize); |
236 | } |
237 | void getBaserels(std::vector<Baserel> *res); |
238 | bool isCOMDAT() const; |
239 | void applyRelocation(uint8_t *off, const coff_relocation &rel) const; |
240 | void applyRelX64(uint8_t *off, uint16_t type, OutputSection *os, uint64_t s, |
241 | uint64_t p, uint64_t imageBase) const; |
242 | void applyRelX86(uint8_t *off, uint16_t type, OutputSection *os, uint64_t s, |
243 | uint64_t p, uint64_t imageBase) const; |
244 | void applyRelARM(uint8_t *off, uint16_t type, OutputSection *os, uint64_t s, |
245 | uint64_t p, uint64_t imageBase) const; |
246 | void applyRelARM64(uint8_t *off, uint16_t type, OutputSection *os, uint64_t s, |
247 | uint64_t p, uint64_t imageBase) const; |
248 | |
249 | void getRuntimePseudoRelocs(std::vector<RuntimePseudoReloc> &res); |
250 | |
251 | // Called if the garbage collector decides to not include this chunk |
252 | // in a final output. It's supposed to print out a log message to stdout. |
253 | void printDiscardedMessage() const; |
254 | |
255 | // Adds COMDAT associative sections to this COMDAT section. A chunk |
256 | // and its children are treated as a group by the garbage collector. |
257 | void addAssociative(SectionChunk *child); |
258 | |
259 | StringRef getDebugName() const; |
260 | |
261 | // True if this is a codeview debug info chunk. These will not be laid out in |
262 | // the image. Instead they will end up in the PDB, if one is requested. |
263 | bool isCodeView() const { |
264 | return getSectionName() == ".debug" || getSectionName().startswith(Prefix: ".debug$" ); |
265 | } |
266 | |
267 | // True if this is a DWARF debug info or exception handling chunk. |
268 | bool isDWARF() const { |
269 | return getSectionName().startswith(Prefix: ".debug_" ) || getSectionName() == ".eh_frame" ; |
270 | } |
271 | |
272 | // Allow iteration over the bodies of this chunk's relocated symbols. |
273 | llvm::iterator_range<symbol_iterator> symbols() const { |
274 | return llvm::make_range(x: symbol_iterator(file, relocsData), |
275 | y: symbol_iterator(file, relocsData + relocsSize)); |
276 | } |
277 | |
278 | ArrayRef<coff_relocation> getRelocs() const { |
279 | return llvm::ArrayRef(relocsData, relocsSize); |
280 | } |
281 | |
282 | // Reloc setter used by ARM range extension thunk insertion. |
283 | void setRelocs(ArrayRef<coff_relocation> newRelocs) { |
284 | relocsData = newRelocs.data(); |
285 | relocsSize = newRelocs.size(); |
286 | assert(relocsSize == newRelocs.size() && "reloc size truncation" ); |
287 | } |
288 | |
289 | // Single linked list iterator for associated comdat children. |
290 | class AssociatedIterator |
291 | : public llvm::iterator_facade_base< |
292 | AssociatedIterator, std::forward_iterator_tag, SectionChunk> { |
293 | public: |
294 | AssociatedIterator() = default; |
295 | AssociatedIterator(SectionChunk *head) : cur(head) {} |
296 | bool operator==(const AssociatedIterator &r) const { return cur == r.cur; } |
297 | // FIXME: Wrong const-ness, but it makes filter ranges work. |
298 | SectionChunk &operator*() const { return *cur; } |
299 | SectionChunk &operator*() { return *cur; } |
300 | AssociatedIterator &operator++() { |
301 | cur = cur->assocChildren; |
302 | return *this; |
303 | } |
304 | |
305 | private: |
306 | SectionChunk *cur = nullptr; |
307 | }; |
308 | |
309 | // Allow iteration over the associated child chunks for this section. |
310 | llvm::iterator_range<AssociatedIterator> children() const { |
311 | // Associated sections do not have children. The assocChildren field is |
312 | // part of the parent's list of children. |
313 | bool isAssoc = selection == llvm::COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE; |
314 | return llvm::make_range( |
315 | x: AssociatedIterator(isAssoc ? nullptr : assocChildren), |
316 | y: AssociatedIterator(nullptr)); |
317 | } |
318 | |
319 | // The section ID this chunk belongs to in its Obj. |
320 | uint32_t getSectionNumber() const; |
321 | |
322 | ArrayRef<uint8_t> consumeDebugMagic(); |
323 | |
324 | static ArrayRef<uint8_t> consumeDebugMagic(ArrayRef<uint8_t> data, |
325 | StringRef sectionName); |
326 | |
327 | static SectionChunk *findByName(ArrayRef<SectionChunk *> sections, |
328 | StringRef name); |
329 | |
330 | // The file that this chunk was created from. |
331 | ObjFile *file; |
332 | |
333 | // Pointer to the COFF section header in the input file. |
334 | const coff_section *; |
335 | |
336 | // The COMDAT leader symbol if this is a COMDAT chunk. |
337 | DefinedRegular *sym = nullptr; |
338 | |
339 | // The CRC of the contents as described in the COFF spec 4.5.5. |
340 | // Auxiliary Format 5: Section Definitions. Used for ICF. |
341 | uint32_t checksum = 0; |
342 | |
343 | // Used by the garbage collector. |
344 | bool live; |
345 | |
346 | // Whether this section needs to be kept distinct from other sections during |
347 | // ICF. This is set by the driver using address-significance tables. |
348 | bool keepUnique = false; |
349 | |
350 | // The COMDAT selection if this is a COMDAT chunk. |
351 | llvm::COFF::COMDATType selection = (llvm::COFF::COMDATType)0; |
352 | |
353 | // A pointer pointing to a replacement for this chunk. |
354 | // Initially it points to "this" object. If this chunk is merged |
355 | // with other chunk by ICF, it points to another chunk, |
356 | // and this chunk is considered as dead. |
357 | SectionChunk *repl; |
358 | |
359 | private: |
360 | SectionChunk *assocChildren = nullptr; |
361 | |
362 | // Used for ICF (Identical COMDAT Folding) |
363 | void replace(SectionChunk *other); |
364 | uint32_t eqClass[2] = {0, 0}; |
365 | |
366 | // Relocations for this section. Size is stored below. |
367 | const coff_relocation *relocsData; |
368 | |
369 | // Section name string. Size is stored below. |
370 | const char *sectionNameData; |
371 | |
372 | uint32_t relocsSize = 0; |
373 | uint32_t sectionNameSize = 0; |
374 | }; |
375 | |
376 | // Inline methods to implement faux-virtual dispatch for SectionChunk. |
377 | |
378 | inline size_t Chunk::getSize() const { |
379 | if (isa<SectionChunk>(Val: this)) |
380 | return static_cast<const SectionChunk *>(this)->getSize(); |
381 | else |
382 | return static_cast<const NonSectionChunk *>(this)->getSize(); |
383 | } |
384 | |
385 | inline uint32_t Chunk::getOutputCharacteristics() const { |
386 | if (isa<SectionChunk>(Val: this)) |
387 | return static_cast<const SectionChunk *>(this)->getOutputCharacteristics(); |
388 | else |
389 | return static_cast<const NonSectionChunk *>(this) |
390 | ->getOutputCharacteristics(); |
391 | } |
392 | |
393 | inline void Chunk::writeTo(uint8_t *buf) const { |
394 | if (isa<SectionChunk>(Val: this)) |
395 | static_cast<const SectionChunk *>(this)->writeTo(buf); |
396 | else |
397 | static_cast<const NonSectionChunk *>(this)->writeTo(buf); |
398 | } |
399 | |
400 | inline StringRef Chunk::getSectionName() const { |
401 | if (isa<SectionChunk>(Val: this)) |
402 | return static_cast<const SectionChunk *>(this)->getSectionName(); |
403 | else |
404 | return static_cast<const NonSectionChunk *>(this)->getSectionName(); |
405 | } |
406 | |
407 | inline void Chunk::getBaserels(std::vector<Baserel> *res) { |
408 | if (isa<SectionChunk>(Val: this)) |
409 | static_cast<SectionChunk *>(this)->getBaserels(res); |
410 | else |
411 | static_cast<NonSectionChunk *>(this)->getBaserels(res); |
412 | } |
413 | |
414 | inline StringRef Chunk::getDebugName() const { |
415 | if (isa<SectionChunk>(Val: this)) |
416 | return static_cast<const SectionChunk *>(this)->getDebugName(); |
417 | else |
418 | return static_cast<const NonSectionChunk *>(this)->getDebugName(); |
419 | } |
420 | |
421 | // This class is used to implement an lld-specific feature (not implemented in |
422 | // MSVC) that minimizes the output size by finding string literals sharing tail |
423 | // parts and merging them. |
424 | // |
425 | // If string tail merging is enabled and a section is identified as containing a |
426 | // string literal, it is added to a MergeChunk with an appropriate alignment. |
427 | // The MergeChunk then tail merges the strings using the StringTableBuilder |
428 | // class and assigns RVAs and section offsets to each of the member chunks based |
429 | // on the offsets assigned by the StringTableBuilder. |
430 | class MergeChunk : public NonSectionChunk { |
431 | public: |
432 | MergeChunk(uint32_t alignment); |
433 | static void addSection(COFFLinkerContext &ctx, SectionChunk *c); |
434 | void finalizeContents(); |
435 | void assignSubsectionRVAs(); |
436 | |
437 | uint32_t getOutputCharacteristics() const override; |
438 | StringRef getSectionName() const override { return ".rdata" ; } |
439 | size_t getSize() const override; |
440 | void writeTo(uint8_t *buf) const override; |
441 | |
442 | std::vector<SectionChunk *> sections; |
443 | |
444 | private: |
445 | llvm::StringTableBuilder builder; |
446 | bool finalized = false; |
447 | }; |
448 | |
449 | // A chunk for common symbols. Common chunks don't have actual data. |
450 | class CommonChunk : public NonSectionChunk { |
451 | public: |
452 | CommonChunk(const COFFSymbolRef sym); |
453 | size_t getSize() const override { return sym.getValue(); } |
454 | uint32_t getOutputCharacteristics() const override; |
455 | StringRef getSectionName() const override { return ".bss" ; } |
456 | |
457 | private: |
458 | const COFFSymbolRef sym; |
459 | }; |
460 | |
461 | // A chunk for linker-created strings. |
462 | class StringChunk : public NonSectionChunk { |
463 | public: |
464 | explicit StringChunk(StringRef s) : str(s) {} |
465 | size_t getSize() const override { return str.size() + 1; } |
466 | void writeTo(uint8_t *buf) const override; |
467 | |
468 | private: |
469 | StringRef str; |
470 | }; |
471 | |
472 | static const uint8_t importThunkX86[] = { |
473 | 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // JMP *0x0 |
474 | }; |
475 | |
476 | static const uint8_t importThunkARM[] = { |
477 | 0x40, 0xf2, 0x00, 0x0c, // mov.w ip, #0 |
478 | 0xc0, 0xf2, 0x00, 0x0c, // mov.t ip, #0 |
479 | 0xdc, 0xf8, 0x00, 0xf0, // ldr.w pc, [ip] |
480 | }; |
481 | |
482 | static const uint8_t importThunkARM64[] = { |
483 | 0x10, 0x00, 0x00, 0x90, // adrp x16, #0 |
484 | 0x10, 0x02, 0x40, 0xf9, // ldr x16, [x16] |
485 | 0x00, 0x02, 0x1f, 0xd6, // br x16 |
486 | }; |
487 | |
488 | // Windows-specific. |
489 | // A chunk for DLL import jump table entry. In a final output, its |
490 | // contents will be a JMP instruction to some __imp_ symbol. |
491 | class ImportThunkChunk : public NonSectionChunk { |
492 | public: |
493 | ImportThunkChunk(COFFLinkerContext &ctx, Defined *s) |
494 | : NonSectionChunk(ImportThunkKind), impSymbol(s), ctx(ctx) {} |
495 | static bool classof(const Chunk *c) { return c->kind() == ImportThunkKind; } |
496 | |
497 | protected: |
498 | Defined *impSymbol; |
499 | COFFLinkerContext &ctx; |
500 | }; |
501 | |
502 | class ImportThunkChunkX64 : public ImportThunkChunk { |
503 | public: |
504 | explicit ImportThunkChunkX64(COFFLinkerContext &ctx, Defined *s); |
505 | size_t getSize() const override { return sizeof(importThunkX86); } |
506 | void writeTo(uint8_t *buf) const override; |
507 | }; |
508 | |
509 | class ImportThunkChunkX86 : public ImportThunkChunk { |
510 | public: |
511 | explicit ImportThunkChunkX86(COFFLinkerContext &ctx, Defined *s) |
512 | : ImportThunkChunk(ctx, s) {} |
513 | size_t getSize() const override { return sizeof(importThunkX86); } |
514 | void getBaserels(std::vector<Baserel> *res) override; |
515 | void writeTo(uint8_t *buf) const override; |
516 | }; |
517 | |
518 | class ImportThunkChunkARM : public ImportThunkChunk { |
519 | public: |
520 | explicit ImportThunkChunkARM(COFFLinkerContext &ctx, Defined *s) |
521 | : ImportThunkChunk(ctx, s) { |
522 | setAlignment(2); |
523 | } |
524 | size_t getSize() const override { return sizeof(importThunkARM); } |
525 | void getBaserels(std::vector<Baserel> *res) override; |
526 | void writeTo(uint8_t *buf) const override; |
527 | }; |
528 | |
529 | class ImportThunkChunkARM64 : public ImportThunkChunk { |
530 | public: |
531 | explicit ImportThunkChunkARM64(COFFLinkerContext &ctx, Defined *s) |
532 | : ImportThunkChunk(ctx, s) { |
533 | setAlignment(4); |
534 | } |
535 | size_t getSize() const override { return sizeof(importThunkARM64); } |
536 | void writeTo(uint8_t *buf) const override; |
537 | }; |
538 | |
539 | class RangeExtensionThunkARM : public NonSectionChunk { |
540 | public: |
541 | explicit RangeExtensionThunkARM(COFFLinkerContext &ctx, Defined *t) |
542 | : target(t), ctx(ctx) { |
543 | setAlignment(2); |
544 | } |
545 | size_t getSize() const override; |
546 | void writeTo(uint8_t *buf) const override; |
547 | |
548 | Defined *target; |
549 | |
550 | private: |
551 | COFFLinkerContext &ctx; |
552 | }; |
553 | |
554 | class RangeExtensionThunkARM64 : public NonSectionChunk { |
555 | public: |
556 | explicit RangeExtensionThunkARM64(COFFLinkerContext &ctx, Defined *t) |
557 | : target(t), ctx(ctx) { |
558 | setAlignment(4); |
559 | } |
560 | size_t getSize() const override; |
561 | void writeTo(uint8_t *buf) const override; |
562 | |
563 | Defined *target; |
564 | |
565 | private: |
566 | COFFLinkerContext &ctx; |
567 | }; |
568 | |
569 | // Windows-specific. |
570 | // See comments for DefinedLocalImport class. |
571 | class LocalImportChunk : public NonSectionChunk { |
572 | public: |
573 | explicit LocalImportChunk(COFFLinkerContext &ctx, Defined *s); |
574 | size_t getSize() const override; |
575 | void getBaserels(std::vector<Baserel> *res) override; |
576 | void writeTo(uint8_t *buf) const override; |
577 | |
578 | private: |
579 | Defined *sym; |
580 | COFFLinkerContext &ctx; |
581 | }; |
582 | |
583 | // Duplicate RVAs are not allowed in RVA tables, so unique symbols by chunk and |
584 | // offset into the chunk. Order does not matter as the RVA table will be sorted |
585 | // later. |
586 | struct ChunkAndOffset { |
587 | Chunk *inputChunk; |
588 | uint32_t offset; |
589 | |
590 | struct DenseMapInfo { |
591 | static ChunkAndOffset getEmptyKey() { |
592 | return {.inputChunk: llvm::DenseMapInfo<Chunk *>::getEmptyKey(), .offset: 0}; |
593 | } |
594 | static ChunkAndOffset getTombstoneKey() { |
595 | return {.inputChunk: llvm::DenseMapInfo<Chunk *>::getTombstoneKey(), .offset: 0}; |
596 | } |
597 | static unsigned getHashValue(const ChunkAndOffset &co) { |
598 | return llvm::DenseMapInfo<std::pair<Chunk *, uint32_t>>::getHashValue( |
599 | PairVal: {co.inputChunk, co.offset}); |
600 | } |
601 | static bool isEqual(const ChunkAndOffset &lhs, const ChunkAndOffset &rhs) { |
602 | return lhs.inputChunk == rhs.inputChunk && lhs.offset == rhs.offset; |
603 | } |
604 | }; |
605 | }; |
606 | |
607 | using SymbolRVASet = llvm::DenseSet<ChunkAndOffset>; |
608 | |
609 | // Table which contains symbol RVAs. Used for /safeseh and /guard:cf. |
610 | class RVATableChunk : public NonSectionChunk { |
611 | public: |
612 | explicit RVATableChunk(SymbolRVASet s) : syms(std::move(s)) {} |
613 | size_t getSize() const override { return syms.size() * 4; } |
614 | void writeTo(uint8_t *buf) const override; |
615 | |
616 | private: |
617 | SymbolRVASet syms; |
618 | }; |
619 | |
620 | // Table which contains symbol RVAs with flags. Used for /guard:ehcont. |
621 | class RVAFlagTableChunk : public NonSectionChunk { |
622 | public: |
623 | explicit RVAFlagTableChunk(SymbolRVASet s) : syms(std::move(s)) {} |
624 | size_t getSize() const override { return syms.size() * 5; } |
625 | void writeTo(uint8_t *buf) const override; |
626 | |
627 | private: |
628 | SymbolRVASet syms; |
629 | }; |
630 | |
631 | // Windows-specific. |
632 | // This class represents a block in .reloc section. |
633 | // See the PE/COFF spec 5.6 for details. |
634 | class BaserelChunk : public NonSectionChunk { |
635 | public: |
636 | BaserelChunk(uint32_t page, Baserel *begin, Baserel *end); |
637 | size_t getSize() const override { return data.size(); } |
638 | void writeTo(uint8_t *buf) const override; |
639 | |
640 | private: |
641 | std::vector<uint8_t> data; |
642 | }; |
643 | |
644 | class Baserel { |
645 | public: |
646 | Baserel(uint32_t v, uint8_t ty) : rva(v), type(ty) {} |
647 | explicit Baserel(uint32_t v, llvm::COFF::MachineTypes machine) |
648 | : Baserel(v, getDefaultType(machine)) {} |
649 | uint8_t getDefaultType(llvm::COFF::MachineTypes machine); |
650 | |
651 | uint32_t rva; |
652 | uint8_t type; |
653 | }; |
654 | |
655 | // This is a placeholder Chunk, to allow attaching a DefinedSynthetic to a |
656 | // specific place in a section, without any data. This is used for the MinGW |
657 | // specific symbol __RUNTIME_PSEUDO_RELOC_LIST_END__, even though the concept |
658 | // of an empty chunk isn't MinGW specific. |
659 | class EmptyChunk : public NonSectionChunk { |
660 | public: |
661 | EmptyChunk() {} |
662 | size_t getSize() const override { return 0; } |
663 | void writeTo(uint8_t *buf) const override {} |
664 | }; |
665 | |
666 | // MinGW specific, for the "automatic import of variables from DLLs" feature. |
667 | // This provides the table of runtime pseudo relocations, for variable |
668 | // references that turned out to need to be imported from a DLL even though |
669 | // the reference didn't use the dllimport attribute. The MinGW runtime will |
670 | // process this table after loading, before handling control over to user |
671 | // code. |
672 | class PseudoRelocTableChunk : public NonSectionChunk { |
673 | public: |
674 | PseudoRelocTableChunk(std::vector<RuntimePseudoReloc> &relocs) |
675 | : relocs(std::move(relocs)) { |
676 | setAlignment(4); |
677 | } |
678 | size_t getSize() const override; |
679 | void writeTo(uint8_t *buf) const override; |
680 | |
681 | private: |
682 | std::vector<RuntimePseudoReloc> relocs; |
683 | }; |
684 | |
685 | // MinGW specific. A Chunk that contains one pointer-sized absolute value. |
686 | class AbsolutePointerChunk : public NonSectionChunk { |
687 | public: |
688 | AbsolutePointerChunk(COFFLinkerContext &ctx, uint64_t value) |
689 | : value(value), ctx(ctx) { |
690 | setAlignment(getSize()); |
691 | } |
692 | size_t getSize() const override; |
693 | void writeTo(uint8_t *buf) const override; |
694 | |
695 | private: |
696 | uint64_t value; |
697 | COFFLinkerContext &ctx; |
698 | }; |
699 | |
700 | // Return true if this file has the hotpatch flag set to true in the S_COMPILE3 |
701 | // record in codeview debug info. Also returns true for some thunks synthesized |
702 | // by the linker. |
703 | inline bool Chunk::isHotPatchable() const { |
704 | if (auto *sc = dyn_cast<SectionChunk>(Val: this)) |
705 | return sc->file->hotPatchable; |
706 | else if (isa<ImportThunkChunk>(Val: this)) |
707 | return true; |
708 | return false; |
709 | } |
710 | |
711 | void applyMOV32T(uint8_t *off, uint32_t v); |
712 | void applyBranch24T(uint8_t *off, int32_t v); |
713 | |
714 | void applyArm64Addr(uint8_t *off, uint64_t s, uint64_t p, int shift); |
715 | void applyArm64Imm(uint8_t *off, uint64_t imm, uint32_t rangeLimit); |
716 | void applyArm64Branch26(uint8_t *off, int64_t v); |
717 | |
718 | // Convenience class for initializing a coff_section with specific flags. |
719 | class FakeSection { |
720 | public: |
721 | FakeSection(int c) { section.Characteristics = c; } |
722 | |
723 | coff_section section; |
724 | }; |
725 | |
726 | // Convenience class for initializing a SectionChunk with specific flags. |
727 | class FakeSectionChunk { |
728 | public: |
729 | FakeSectionChunk(const coff_section *section) : chunk(nullptr, section) { |
730 | // Comdats from LTO files can't be fully treated as regular comdats |
731 | // at this point; we don't know what size or contents they are going to |
732 | // have, so we can't do proper checking of such aspects of them. |
733 | chunk.selection = llvm::COFF::IMAGE_COMDAT_SELECT_ANY; |
734 | } |
735 | |
736 | SectionChunk chunk; |
737 | }; |
738 | |
739 | } // namespace lld::coff |
740 | |
741 | namespace llvm { |
742 | template <> |
743 | struct DenseMapInfo<lld::coff::ChunkAndOffset> |
744 | : lld::coff::ChunkAndOffset::DenseMapInfo {}; |
745 | } |
746 | |
747 | #endif |
748 | |