1//===- lib/MC/GOFFObjectWriter.cpp - GOFF File Writer ---------------------===//
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// This file implements GOFF object file writer information.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/BinaryFormat/GOFF.h"
14#include "llvm/MC/MCAsmBackend.h"
15#include "llvm/MC/MCAssembler.h"
16#include "llvm/MC/MCGOFFAttributes.h"
17#include "llvm/MC/MCGOFFObjectWriter.h"
18#include "llvm/MC/MCObjectWriter.h"
19#include "llvm/MC/MCSectionGOFF.h"
20#include "llvm/MC/MCSymbolGOFF.h"
21#include "llvm/MC/MCValue.h"
22#include "llvm/Support/ConvertEBCDIC.h"
23#include "llvm/Support/Debug.h"
24#include "llvm/Support/Endian.h"
25#include "llvm/Support/raw_ostream.h"
26
27using namespace llvm;
28
29#define DEBUG_TYPE "goff-writer"
30
31namespace {
32// Common flag values on records.
33
34// Flag: This record is continued.
35constexpr uint8_t RecContinued = GOFF::Flags(7, 1, 1);
36
37// Flag: This record is a continuation.
38constexpr uint8_t RecContinuation = GOFF::Flags(6, 1, 1);
39
40// The GOFFOstream is responsible to write the data into the fixed physical
41// records of the format. A user of this class announces the begin of a new
42// logical record. While writing the payload, the physical records are created
43// for the data. Possible fill bytes at the end of a physical record are written
44// automatically. In principle, the GOFFOstream is agnostic of the endianness of
45// the payload. However, it also supports writing data in big endian byte order.
46//
47// The physical records use the flag field to indicate if the there is a
48// successor and predecessor record. To be able to set these flags while
49// writing, the basic implementation idea is to always buffer the last seen
50// physical record.
51class GOFFOstream {
52 /// The underlying raw_pwrite_stream.
53 raw_pwrite_stream &OS;
54
55 /// The number of logical records emitted so far.
56 uint32_t LogicalRecords = 0;
57
58 /// The number of physical records emitted so far.
59 uint32_t PhysicalRecords = 0;
60
61 /// The size of the buffer. Same as the payload size of a physical record.
62 static constexpr uint8_t BufferSize = GOFF::PayloadLength;
63
64 /// Current position in buffer.
65 char *BufferPtr = Buffer;
66
67 /// Static allocated buffer for the stream.
68 char Buffer[BufferSize];
69
70 /// The type of the current logical record, and the flags (aka continued and
71 /// continuation indicators) for the previous (physical) record.
72 uint8_t TypeAndFlags = 0;
73
74public:
75 GOFFOstream(raw_pwrite_stream &OS);
76 ~GOFFOstream();
77
78 raw_pwrite_stream &getOS() { return OS; }
79 size_t getWrittenSize() const { return PhysicalRecords * GOFF::RecordLength; }
80 uint32_t getNumLogicalRecords() { return LogicalRecords; }
81
82 /// Write the specified bytes.
83 void write(const char *Ptr, size_t Size);
84
85 /// Write zeroes, up to a maximum of 16 bytes.
86 void write_zeros(unsigned NumZeros);
87
88 /// Support for endian-specific data.
89 template <typename value_type> void writebe(value_type Value) {
90 Value =
91 support::endian::byte_swap<value_type>(Value, llvm::endianness::big);
92 write(Ptr: (const char *)&Value, Size: sizeof(value_type));
93 }
94
95 /// Begin a new logical record. Implies finalizing the previous record.
96 void newRecord(GOFF::RecordType Type);
97
98 /// Ends a logical record.
99 void finalizeRecord();
100
101private:
102 /// Updates the continued/continuation flags, and writes the record prefix of
103 /// a physical record.
104 void updateFlagsAndWritePrefix(bool IsContinued);
105
106 /// Returns the remaining size in the buffer.
107 size_t getRemainingSize();
108};
109} // namespace
110
111GOFFOstream::GOFFOstream(raw_pwrite_stream &OS) : OS(OS) {}
112
113GOFFOstream::~GOFFOstream() { finalizeRecord(); }
114
115void GOFFOstream::updateFlagsAndWritePrefix(bool IsContinued) {
116 // Update the flags based on the previous state and the flag IsContinued.
117 if (TypeAndFlags & RecContinued)
118 TypeAndFlags |= RecContinuation;
119 if (IsContinued)
120 TypeAndFlags |= RecContinued;
121 else
122 TypeAndFlags &= ~RecContinued;
123
124 OS << static_cast<unsigned char>(GOFF::PTVPrefix) // Record Type
125 << static_cast<unsigned char>(TypeAndFlags) // Continuation
126 << static_cast<unsigned char>(0); // Version
127
128 ++PhysicalRecords;
129}
130
131size_t GOFFOstream::getRemainingSize() {
132 return size_t(&Buffer[BufferSize] - BufferPtr);
133}
134
135void GOFFOstream::write(const char *Ptr, size_t Size) {
136 size_t RemainingSize = getRemainingSize();
137
138 // Data fits into the buffer.
139 if (LLVM_LIKELY(Size <= RemainingSize)) {
140 memcpy(dest: BufferPtr, src: Ptr, n: Size);
141 BufferPtr += Size;
142 return;
143 }
144
145 // Otherwise the buffer is partially filled or full, and data does not fit
146 // into it.
147 updateFlagsAndWritePrefix(/*IsContinued=*/true);
148 OS.write(Ptr: Buffer, Size: size_t(BufferPtr - Buffer));
149 if (RemainingSize > 0) {
150 OS.write(Ptr, Size: RemainingSize);
151 Ptr += RemainingSize;
152 Size -= RemainingSize;
153 }
154
155 while (Size > BufferSize) {
156 updateFlagsAndWritePrefix(/*IsContinued=*/true);
157 OS.write(Ptr, Size: BufferSize);
158 Ptr += BufferSize;
159 Size -= BufferSize;
160 }
161
162 // The remaining bytes fit into the buffer.
163 memcpy(dest: Buffer, src: Ptr, n: Size);
164 BufferPtr = &Buffer[Size];
165}
166
167void GOFFOstream::write_zeros(unsigned NumZeros) {
168 assert(NumZeros <= 16 && "Range for zeros too large");
169
170 // Handle the common case first: all fits in the buffer.
171 size_t RemainingSize = getRemainingSize();
172 if (LLVM_LIKELY(RemainingSize >= NumZeros)) {
173 memset(s: BufferPtr, c: 0, n: NumZeros);
174 BufferPtr += NumZeros;
175 return;
176 }
177
178 // Otherwise some field value is cleared.
179 static char Zeros[16] = {
180 0,
181 };
182 write(Ptr: Zeros, Size: NumZeros);
183}
184
185void GOFFOstream::newRecord(GOFF::RecordType Type) {
186 finalizeRecord();
187 TypeAndFlags = Type << 4;
188 ++LogicalRecords;
189}
190
191void GOFFOstream::finalizeRecord() {
192 if (Buffer == BufferPtr)
193 return;
194 updateFlagsAndWritePrefix(/*IsContinued=*/false);
195 OS.write(Ptr: Buffer, Size: size_t(BufferPtr - Buffer));
196 OS.write_zeros(NumZeros: getRemainingSize());
197 BufferPtr = Buffer;
198}
199
200namespace {
201// A GOFFSymbol holds all the data required for writing an ESD record.
202class GOFFSymbol {
203public:
204 std::string Name;
205 uint32_t EsdId;
206 uint32_t ParentEsdId;
207 uint64_t Offset = 0; // Offset of the symbol into the section. LD only.
208 // Offset is only 32 bit, the larger type is used to
209 // enable error checking.
210 GOFF::ESDSymbolType SymbolType;
211 GOFF::ESDNameSpaceId NameSpace = GOFF::ESD_NS_ProgramManagementBinder;
212
213 GOFF::BehavioralAttributes BehavAttrs;
214 GOFF::SymbolFlags SymbolFlags;
215 uint32_t SortKey = 0;
216 uint32_t SectionLength = 0;
217 uint32_t ADAEsdId = 0;
218 uint32_t EASectionEDEsdId = 0;
219 uint32_t EASectionOffset = 0;
220 uint8_t FillByteValue = 0;
221
222 GOFFSymbol() : EsdId(0), ParentEsdId(0) {}
223
224 GOFFSymbol(StringRef Name, uint32_t EsdID, const GOFF::SDAttr &Attr)
225 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(0),
226 SymbolType(GOFF::ESD_ST_SectionDefinition) {
227 BehavAttrs.setTaskingBehavior(Attr.TaskingBehavior);
228 BehavAttrs.setBindingScope(Attr.BindingScope);
229 }
230
231 GOFFSymbol(StringRef Name, uint32_t EsdID, uint32_t ParentEsdID,
232 const GOFF::EDAttr &Attr)
233 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
234 SymbolType(GOFF::ESD_ST_ElementDefinition) {
235 this->NameSpace = Attr.NameSpace;
236 // We always set a fill byte value.
237 this->FillByteValue = Attr.FillByteValue;
238 SymbolFlags.setFillBytePresence(1);
239 SymbolFlags.setReservedQwords(Attr.ReservedQwords);
240 // TODO Do we need/should set the "mangled" flag?
241 BehavAttrs.setReadOnly(Attr.IsReadOnly);
242 BehavAttrs.setRmode(Attr.Rmode);
243 BehavAttrs.setTextStyle(Attr.TextStyle);
244 BehavAttrs.setBindingAlgorithm(Attr.BindAlgorithm);
245 BehavAttrs.setLoadingBehavior(Attr.LoadBehavior);
246 BehavAttrs.setAlignment(Attr.Alignment);
247 }
248
249 GOFFSymbol(StringRef Name, uint32_t EsdID, uint32_t ParentEsdID,
250 GOFF::ESDNameSpaceId NameSpace, const GOFF::LDAttr &Attr)
251 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
252 SymbolType(GOFF::ESD_ST_LabelDefinition), NameSpace(NameSpace) {
253 SymbolFlags.setRenameable(Attr.IsRenamable);
254 BehavAttrs.setExecutable(Attr.Executable);
255 BehavAttrs.setBindingStrength(Attr.BindingStrength);
256 BehavAttrs.setLinkageType(Attr.Linkage);
257 BehavAttrs.setAmode(Attr.Amode);
258 BehavAttrs.setBindingScope(Attr.BindingScope);
259 }
260
261 GOFFSymbol(StringRef Name, uint32_t EsdID, uint32_t ParentEsdID,
262 const GOFF::EDAttr &EDAttr, const GOFF::PRAttr &Attr)
263 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
264 SymbolType(GOFF::ESD_ST_PartReference), NameSpace(EDAttr.NameSpace) {
265 SymbolFlags.setRenameable(Attr.IsRenamable);
266 BehavAttrs.setExecutable(Attr.Executable);
267 BehavAttrs.setLinkageType(Attr.Linkage);
268 BehavAttrs.setBindingScope(Attr.BindingScope);
269 BehavAttrs.setAlignment(EDAttr.Alignment);
270 }
271
272 GOFFSymbol(StringRef Name, uint32_t EsdID, uint32_t ParentEsdID,
273 const GOFF::ERAttr &Attr)
274 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
275 SymbolType(GOFF::ESD_ST_ExternalReference),
276 NameSpace(GOFF::ESD_NS_NormalName) {
277 BehavAttrs.setExecutable(Attr.Executable);
278 BehavAttrs.setBindingStrength(Attr.BindingStrength);
279 BehavAttrs.setLinkageType(Attr.Linkage);
280 BehavAttrs.setAmode(Attr.Amode);
281 BehavAttrs.setBindingScope(Attr.BindingScope);
282 BehavAttrs.setIndirectReference(Attr.IsIndirectReference);
283 }
284};
285
286class GOFFWriter {
287 GOFFOstream OS;
288 MCAssembler &Asm;
289 MCSectionGOFF *RootSD;
290
291 /// Saved relocation data collected in recordRelocations().
292 std::vector<GOFFRelocationEntry> &Relocations;
293
294 void writeHeader();
295 void writeSymbol(const GOFFSymbol &Symbol);
296 void writeText(const MCSectionGOFF *MC);
297 void writeRelocations();
298 void writeEnd();
299
300 void defineSectionSymbols(const MCSectionGOFF &Section);
301 void defineLabel(const MCSymbolGOFF &Symbol);
302 void defineExtern(const MCSymbolGOFF &Symbol);
303 void defineSymbols();
304
305public:
306 GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm, MCSectionGOFF *RootSD,
307 std::vector<GOFFRelocationEntry> &Relocations);
308 uint64_t writeObject();
309};
310} // namespace
311
312GOFFWriter::GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm,
313 MCSectionGOFF *RootSD,
314 std::vector<GOFFRelocationEntry> &Relocations)
315 : OS(OS), Asm(Asm), RootSD(RootSD), Relocations(Relocations) {}
316
317void GOFFWriter::defineSectionSymbols(const MCSectionGOFF &Section) {
318 if (Section.isSD()) {
319 GOFFSymbol SD(Section.getExternalName(), Section.getOrdinal(),
320 Section.getSDAttributes());
321 writeSymbol(Symbol: SD);
322 }
323
324 if (Section.isED()) {
325 GOFFSymbol ED(Section.getExternalName(), Section.getOrdinal(),
326 Section.getParent()->getOrdinal(), Section.getEDAttributes());
327 ED.SectionLength = Asm.getSectionAddressSize(Sec: Section);
328 writeSymbol(Symbol: ED);
329 }
330
331 if (Section.isPR()) {
332 MCSectionGOFF *Parent = Section.getParent();
333 GOFFSymbol PR(Section.getExternalName(), Section.getOrdinal(),
334 Parent->getOrdinal(), Parent->getEDAttributes(),
335 Section.getPRAttributes());
336 PR.SectionLength = Asm.getSectionAddressSize(Sec: Section);
337 if (Section.requiresNonZeroLength()) {
338 // We cannot have a zero-length section for data. If we do,
339 // artificially inflate it. Use 2 bytes to avoid odd alignments. Note:
340 // if this is ever changed, you will need to update the code in
341 // SystemZAsmPrinter::emitCEEMAIN and SystemZAsmPrinter::emitCELQMAIN to
342 // generate -1 if there is no ADA
343 if (!PR.SectionLength)
344 PR.SectionLength = 2;
345 }
346 writeSymbol(Symbol: PR);
347 }
348}
349
350void GOFFWriter::defineLabel(const MCSymbolGOFF &Symbol) {
351 MCSectionGOFF &Section = static_cast<MCSectionGOFF &>(Symbol.getSection());
352 GOFFSymbol LD(Symbol.getExternalName(), Symbol.getIndex(),
353 Section.getOrdinal(), Section.getEDAttributes().NameSpace,
354 GOFF::LDAttr{.IsRenamable: false, .Executable: Symbol.getCodeData(),
355 .BindingStrength: Symbol.getBindingStrength(), .Linkage: Symbol.getLinkage(),
356 .Amode: GOFF::ESD_AMODE_64, .BindingScope: Symbol.getBindingScope()});
357 if (Symbol.getADA())
358 LD.ADAEsdId = Symbol.getADA()->getOrdinal();
359 LD.Offset = Asm.getSymbolOffset(S: Symbol);
360 writeSymbol(Symbol: LD);
361}
362
363void GOFFWriter::defineExtern(const MCSymbolGOFF &Symbol) {
364 if (Symbol.getCodeData() == GOFF::ESD_EXE_DATA) {
365 MCSectionGOFF *ED = Symbol.getADA()->getParent();
366 GOFFSymbol PR(Symbol.getExternalName(), Symbol.getIndex(), ED->getOrdinal(),
367 ED->getEDAttributes(),
368 GOFF::PRAttr{/*IsRenamable*/ false, .Executable: Symbol.getCodeData(),
369 .Linkage: Symbol.getLinkage(), .BindingScope: Symbol.getBindingScope(),
370 .SortKey: 0});
371 writeSymbol(Symbol: PR);
372 } else {
373 GOFFSymbol ER(Symbol.getExternalName(), Symbol.getIndex(),
374 RootSD->getOrdinal(),
375 GOFF::ERAttr{.IsIndirectReference: Symbol.isIndirect(), .Executable: Symbol.getCodeData(),
376 .BindingStrength: Symbol.getBindingStrength(), .Linkage: Symbol.getLinkage(),
377 .Amode: GOFF::ESD_AMODE_64, .BindingScope: Symbol.getBindingScope()});
378 writeSymbol(Symbol: ER);
379 }
380}
381
382void GOFFWriter::defineSymbols() {
383 unsigned Ordinal = 0;
384 // Process all sections.
385 for (MCSection &S : Asm) {
386 auto &Section = static_cast<MCSectionGOFF &>(S);
387 Section.setOrdinal(++Ordinal);
388 defineSectionSymbols(Section);
389 }
390
391 // Process all symbols
392 for (const MCSymbol &Sym : Asm.symbols()) {
393 if (Sym.isTemporary())
394 continue;
395 auto &Symbol = static_cast<const MCSymbolGOFF &>(Sym);
396 if (!Symbol.isDefined()) {
397 Symbol.setIndex(++Ordinal);
398 defineExtern(Symbol);
399 } else if (Symbol.isInEDSection()) {
400 Symbol.setIndex(++Ordinal);
401 defineLabel(Symbol);
402 } else {
403 // Symbol is in PR section, the symbol refers to the section.
404 Symbol.setIndex(Symbol.getSection().getOrdinal());
405 }
406 }
407}
408
409void GOFFWriter::writeHeader() {
410 OS.newRecord(Type: GOFF::RT_HDR);
411 OS.write_zeros(NumZeros: 1); // Reserved
412 OS.writebe<uint32_t>(Value: 0); // Target Hardware Environment
413 OS.writebe<uint32_t>(Value: 0); // Target Operating System Environment
414 OS.write_zeros(NumZeros: 2); // Reserved
415 OS.writebe<uint16_t>(Value: 0); // CCSID
416 OS.write_zeros(NumZeros: 16); // Character Set name
417 OS.write_zeros(NumZeros: 16); // Language Product Identifier
418 OS.writebe<uint32_t>(Value: 1); // Architecture Level
419 OS.writebe<uint16_t>(Value: 0); // Module Properties Length
420 OS.write_zeros(NumZeros: 6); // Reserved
421}
422
423void GOFFWriter::writeSymbol(const GOFFSymbol &Symbol) {
424 if (Symbol.Offset >= (((uint64_t)1) << 31))
425 report_fatal_error(reason: "ESD offset out of range");
426
427 // All symbol names are in EBCDIC.
428 SmallString<256> Name;
429 ConverterEBCDIC::convertToEBCDIC(Source: Symbol.Name, Result&: Name);
430
431 // Check length here since this number is technically signed but we need uint
432 // for writing to records.
433 if (Name.size() >= GOFF::MaxDataLength)
434 report_fatal_error(reason: "Symbol max name length exceeded");
435 uint16_t NameLength = Name.size();
436
437 OS.newRecord(Type: GOFF::RT_ESD);
438 OS.writebe<uint8_t>(Value: Symbol.SymbolType); // Symbol Type
439 OS.writebe<uint32_t>(Value: Symbol.EsdId); // ESDID
440 OS.writebe<uint32_t>(Value: Symbol.ParentEsdId); // Parent or Owning ESDID
441 OS.writebe<uint32_t>(Value: 0); // Reserved
442 OS.writebe<uint32_t>(
443 Value: static_cast<uint32_t>(Symbol.Offset)); // Offset or Address
444 OS.writebe<uint32_t>(Value: 0); // Reserved
445 OS.writebe<uint32_t>(Value: Symbol.SectionLength); // Length
446 OS.writebe<uint32_t>(Value: Symbol.EASectionEDEsdId); // Extended Attribute ESDID
447 OS.writebe<uint32_t>(Value: Symbol.EASectionOffset); // Extended Attribute Offset
448 OS.writebe<uint32_t>(Value: 0); // Reserved
449 OS.writebe<uint8_t>(Value: Symbol.NameSpace); // Name Space ID
450 OS.writebe<uint8_t>(Value: Symbol.SymbolFlags); // Flags
451 OS.writebe<uint8_t>(Value: Symbol.FillByteValue); // Fill-Byte Value
452 OS.writebe<uint8_t>(Value: 0); // Reserved
453 OS.writebe<uint32_t>(Value: Symbol.ADAEsdId); // ADA ESDID
454 OS.writebe<uint32_t>(Value: Symbol.SortKey); // Sort Priority
455 OS.writebe<uint64_t>(Value: 0); // Reserved
456 for (auto F : Symbol.BehavAttrs.Attr)
457 OS.writebe<uint8_t>(Value: F); // Behavioral Attributes
458 OS.writebe<uint16_t>(Value: NameLength); // Name Length
459 OS.write(Ptr: Name.data(), Size: NameLength); // Name
460}
461
462namespace {
463/// Adapter stream to write a text section.
464class TextStream : public raw_ostream {
465 /// The underlying GOFFOstream.
466 GOFFOstream &OS;
467
468 /// The buffer size is the maximum number of bytes in a TXT section.
469 static constexpr size_t BufferSize = GOFF::MaxDataLength;
470
471 /// Static allocated buffer for the stream, used by the raw_ostream class. The
472 /// buffer is sized to hold the payload of a logical TXT record.
473 char Buffer[BufferSize];
474
475 /// The offset for the next TXT record. This is equal to the number of bytes
476 /// written.
477 size_t Offset;
478
479 /// The Esdid of the GOFF section.
480 const uint32_t EsdId;
481
482 /// The record style.
483 const GOFF::ESDTextStyle RecordStyle;
484
485 /// See raw_ostream::write_impl.
486 void write_impl(const char *Ptr, size_t Size) override;
487
488 uint64_t current_pos() const override { return Offset; }
489
490public:
491 explicit TextStream(GOFFOstream &OS, uint32_t EsdId,
492 GOFF::ESDTextStyle RecordStyle)
493 : OS(OS), Offset(0), EsdId(EsdId), RecordStyle(RecordStyle) {
494 SetBuffer(BufferStart: Buffer, Size: sizeof(Buffer));
495 }
496
497 ~TextStream() override { flush(); }
498};
499} // namespace
500
501void TextStream::write_impl(const char *Ptr, size_t Size) {
502 size_t WrittenLength = 0;
503
504 // We only have signed 32bits of offset.
505 if (Offset + Size > std::numeric_limits<int32_t>::max())
506 report_fatal_error(reason: "TXT section too large");
507
508 while (WrittenLength < Size) {
509 size_t ToWriteLength =
510 std::min(a: Size - WrittenLength, b: size_t(GOFF::MaxDataLength));
511
512 OS.newRecord(Type: GOFF::RT_TXT);
513 OS.writebe<uint8_t>(Value: GOFF::Flags(4, 4, RecordStyle)); // Text Record Style
514 OS.writebe<uint32_t>(Value: EsdId); // Element ESDID
515 OS.writebe<uint32_t>(Value: 0); // Reserved
516 OS.writebe<uint32_t>(Value: static_cast<uint32_t>(Offset)); // Offset
517 OS.writebe<uint32_t>(Value: 0); // Text Field True Length
518 OS.writebe<uint16_t>(Value: 0); // Text Encoding
519 OS.writebe<uint16_t>(Value: ToWriteLength); // Data Length
520 OS.write(Ptr: Ptr + WrittenLength, Size: ToWriteLength); // Data
521
522 WrittenLength += ToWriteLength;
523 Offset += ToWriteLength;
524 }
525}
526
527void GOFFWriter::writeText(const MCSectionGOFF *Section) {
528 // A BSS section contains only zeros, no need to write this.
529 if (Section->isBSS())
530 return;
531
532 TextStream S(OS, Section->getOrdinal(), Section->getTextStyle());
533 Asm.writeSectionData(OS&: S, Section);
534}
535
536namespace {
537// RelocDataItemBuffer provides a static buffer for relocation data items.
538class RelocDataItemBuffer {
539 char Buffer[GOFF::MaxDataLength];
540 char *Ptr;
541
542public:
543 RelocDataItemBuffer() : Ptr(Buffer) {}
544 const char *data() { return Buffer; }
545 size_t size() { return Ptr - Buffer; }
546 void reset() { Ptr = Buffer; }
547 bool fits(size_t S) { return size() + S < GOFF::MaxDataLength; }
548 template <typename T> void writebe(T Val) {
549 assert(fits(sizeof(T)) && "Out-of-bounds write");
550 support::endian::write<T, llvm::endianness::big>(Ptr, Val);
551 Ptr += sizeof(T);
552 }
553};
554} // namespace
555
556void GOFFWriter::writeRelocations() {
557 // Set the IDs in the relocation entries.
558 for (auto &RelocEntry : Relocations) {
559 auto GetRptr = [](const MCSymbolGOFF *Sym) -> uint32_t {
560 if (Sym->isTemporary())
561 return static_cast<MCSectionGOFF &>(Sym->getSection())
562 .getBeginSymbol()
563 ->getIndex();
564 return Sym->getIndex();
565 };
566
567 RelocEntry.PEsdId = RelocEntry.Pptr->getOrdinal();
568 RelocEntry.REsdId = GetRptr(RelocEntry.Rptr);
569 }
570
571 // Sort relocation data items by the P pointer to save space.
572 std::sort(
573 first: Relocations.begin(), last: Relocations.end(),
574 comp: [](const GOFFRelocationEntry &Left, const GOFFRelocationEntry &Right) {
575 return std::tie(args: Left.PEsdId, args: Left.REsdId, args: Left.POffset) <
576 std::tie(args: Right.PEsdId, args: Right.REsdId, args: Right.POffset);
577 });
578
579 // Construct the compressed relocation data items, and write them out.
580 RelocDataItemBuffer Buffer;
581 for (auto I = Relocations.begin(), E = Relocations.end(); I != E;) {
582 Buffer.reset();
583
584 uint32_t PrevResdId = -1;
585 uint32_t PrevPesdId = -1;
586 uint64_t PrevPOffset = -1;
587 for (; I != E; ++I) {
588 const GOFFRelocationEntry &Rel = *I;
589
590 bool SameREsdId = (Rel.REsdId == PrevResdId);
591 bool SamePEsdId = (Rel.PEsdId == PrevPesdId);
592 bool SamePOffset = (Rel.POffset == PrevPOffset);
593 bool EightByteOffset = ((Rel.POffset >> 32) & 0xffffffff);
594
595 // Calculate size of relocation data item, and check if it still fits into
596 // the record.
597 size_t ItemSize = 8; // Smallest size of a relocation data item.
598 if (!SameREsdId)
599 ItemSize += 4;
600 if (!SamePEsdId)
601 ItemSize += 4;
602 if (!SamePOffset)
603 ItemSize += (EightByteOffset ? 8 : 4);
604 if (!Buffer.fits(S: ItemSize))
605 break;
606
607 GOFF::Flags RelocFlags[6];
608 RelocFlags[0].set(BitIndex: 0, Length: 1, NewValue: SameREsdId);
609 RelocFlags[0].set(BitIndex: 1, Length: 1, NewValue: SamePEsdId);
610 RelocFlags[0].set(BitIndex: 2, Length: 1, NewValue: SamePOffset);
611 RelocFlags[0].set(BitIndex: 6, Length: 1, NewValue: EightByteOffset);
612
613 RelocFlags[1].set(BitIndex: 0, Length: 4, NewValue: Rel.ReferenceType);
614 RelocFlags[1].set(BitIndex: 4, Length: 4, NewValue: Rel.ReferentType);
615
616 RelocFlags[2].set(BitIndex: 0, Length: 7, NewValue: Rel.Action);
617 RelocFlags[2].set(BitIndex: 7, Length: 1, NewValue: Rel.FetchStore);
618
619 RelocFlags[4].set(BitIndex: 0, Length: 8, NewValue: Rel.TargetLength);
620
621 for (auto F : RelocFlags)
622 Buffer.writebe<uint8_t>(Val: F);
623 Buffer.writebe<uint16_t>(Val: 0); // Reserved.
624 if (!SameREsdId)
625 Buffer.writebe<uint32_t>(Val: Rel.REsdId);
626 if (!SamePEsdId)
627 Buffer.writebe<uint32_t>(Val: Rel.PEsdId);
628 if (!SamePOffset) {
629 if (EightByteOffset)
630 Buffer.writebe<uint64_t>(Val: Rel.POffset);
631 else
632 Buffer.writebe<uint32_t>(Val: Rel.POffset);
633 }
634
635 PrevResdId = Rel.REsdId;
636 PrevPesdId = Rel.PEsdId;
637 PrevPOffset = Rel.POffset;
638 }
639
640 OS.newRecord(Type: GOFF::RT_RLD);
641 OS.writebe<uint8_t>(Value: 0); // Reserved.
642 OS.writebe<uint16_t>(Value: Buffer.size()); // Length (of the relocation data).
643 OS.write(Ptr: Buffer.data(), Size: Buffer.size()); // Relocation Directory Data Items.
644 }
645}
646
647void GOFFWriter::writeEnd() {
648 uint8_t F = GOFF::END_EPR_None;
649 uint8_t AMODE = 0;
650 uint32_t ESDID = 0;
651
652 // TODO Set Flags/AMODE/ESDID for entry point.
653
654 OS.newRecord(Type: GOFF::RT_END);
655 OS.writebe<uint8_t>(Value: GOFF::Flags(6, 2, F)); // Indicator flags
656 OS.writebe<uint8_t>(Value: AMODE); // AMODE
657 OS.write_zeros(NumZeros: 3); // Reserved
658 // The record count is the number of logical records. In principle, this value
659 // is available as OS.logicalRecords(). However, some tools rely on this field
660 // being zero.
661 OS.writebe<uint32_t>(Value: 0); // Record Count
662 OS.writebe<uint32_t>(Value: ESDID); // ESDID (of entry point)
663}
664
665uint64_t GOFFWriter::writeObject() {
666 writeHeader();
667
668 defineSymbols();
669
670 for (const MCSection &Section : Asm)
671 writeText(Section: static_cast<const MCSectionGOFF *>(&Section));
672
673 writeRelocations();
674
675 writeEnd();
676
677 // Make sure all records are written.
678 OS.finalizeRecord();
679
680 LLVM_DEBUG(dbgs() << "Wrote " << OS.getNumLogicalRecords()
681 << " logical records.");
682
683 return OS.getWrittenSize();
684}
685
686GOFFObjectWriter::GOFFObjectWriter(
687 std::unique_ptr<MCGOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS)
688 : TargetObjectWriter(std::move(MOTW)), OS(OS) {}
689
690GOFFObjectWriter::~GOFFObjectWriter() = default;
691
692void GOFFObjectWriter::reset() {
693 Relocations.clear();
694 RootSD = nullptr;
695 MCObjectWriter::reset();
696}
697
698void GOFFObjectWriter::recordRelocation(const MCFragment &F,
699 const MCFixup &Fixup, MCValue Target,
700 uint64_t &FixedValue) {
701 const MCFixupKindInfo &FKI =
702 Asm->getBackend().getFixupKindInfo(Kind: Fixup.getKind());
703 const uint32_t Length = FKI.TargetSize / 8;
704 assert(FKI.TargetSize % 8 == 0 && "Target Size not multiple of 8");
705 const uint64_t FixupOffset = Asm->getFragmentOffset(F) + Fixup.getOffset();
706
707 unsigned RelocType = TargetObjectWriter->getRelocType(Target, Fixup);
708
709 const MCSectionGOFF *PSection = static_cast<MCSectionGOFF *>(F.getParent());
710 const auto &A = *static_cast<const MCSymbolGOFF *>(Target.getAddSym());
711 const MCSymbolGOFF *B = static_cast<const MCSymbolGOFF *>(Target.getSubSym());
712 if (RelocType == MCGOFFObjectTargetWriter::Reloc_Type_RICon) {
713 if (A.isUndefined()) {
714 Asm->reportError(
715 L: Fixup.getLoc(),
716 Msg: Twine("symbol ")
717 .concat(Suffix: A.getExternalName())
718 .concat(Suffix: " must be defined for a relative immediate relocation"));
719 return;
720 }
721 if (&A.getSection() != PSection) {
722 MCSectionGOFF &GOFFSection = static_cast<MCSectionGOFF &>(A.getSection());
723 Asm->reportError(L: Fixup.getLoc(),
724 Msg: Twine("relative immediate relocation section mismatch: ")
725 .concat(Suffix: GOFFSection.getExternalName())
726 .concat(Suffix: " of symbol ")
727 .concat(Suffix: A.getExternalName())
728 .concat(Suffix: " <-> ")
729 .concat(Suffix: PSection->getExternalName()));
730 return;
731 }
732 if (B) {
733 Asm->reportError(
734 L: Fixup.getLoc(),
735 Msg: Twine("subtractive symbol ")
736 .concat(Suffix: B->getExternalName())
737 .concat(Suffix: " not supported for a relative immediate relocation"));
738 return;
739 }
740 FixedValue = Asm->getSymbolOffset(S: A) - FixupOffset + Target.getConstant();
741 return;
742 }
743 FixedValue = Target.getConstant();
744
745 // The symbol only has a section-relative offset if it is a temporary symbol.
746 FixedValue += A.isTemporary() ? Asm->getSymbolOffset(S: A) : 0;
747 A.setUsedInReloc();
748 if (B) {
749 FixedValue -= B->isTemporary() ? Asm->getSymbolOffset(S: *B) : 0;
750 B->setUsedInReloc();
751 }
752
753 // UseQCon causes class offsets versus absolute addresses to be used. This
754 // is analogous to using QCONs in older OBJ object file format.
755 bool UseQCon = RelocType == MCGOFFObjectTargetWriter::Reloc_Type_QCon;
756
757 GOFF::RLDFetchStore FetchStore =
758 (RelocType == MCGOFFObjectTargetWriter::Reloc_Type_RCon ||
759 RelocType == MCGOFFObjectTargetWriter::Reloc_Type_VCon)
760 ? GOFF::RLDFetchStore::RLD_FS_Store
761 : GOFF::RLDFetchStore::RLD_FS_Fetch;
762 assert((FetchStore == GOFF::RLDFetchStore::RLD_FS_Fetch || B == nullptr) &&
763 "No dependent relocations expected");
764
765 enum GOFF::RLDReferenceType ReferenceType = GOFF::RLD_RT_RAddress;
766 enum GOFF::RLDReferentType ReferentType = GOFF::RLD_RO_Label;
767 if (UseQCon) {
768 ReferenceType = GOFF::RLD_RT_ROffset;
769 ReferentType = GOFF::RLD_RO_Class;
770 }
771 if (RelocType == MCGOFFObjectTargetWriter::Reloc_Type_RCon)
772 ReferenceType = GOFF::RLD_RT_RTypeConstant;
773
774 auto DumpReloc = [&PSection, &ReferenceType, &FixupOffset,
775 &FixedValue](const char *N, const MCSymbolGOFF *Sym) {
776 const char *Con;
777 switch (ReferenceType) {
778 case GOFF::RLDReferenceType::RLD_RT_RAddress:
779 Con = "ACon";
780 break;
781 case GOFF::RLDReferenceType::RLD_RT_ROffset:
782 Con = "QCon";
783 break;
784 case GOFF::RLDReferenceType::RLD_RT_RTypeConstant:
785 Con = "VCon";
786 break;
787 default:
788 Con = "(unknown)";
789 }
790 dbgs() << "Reloc " << N << ": " << Con
791 << " Rptr: " << Sym->getExternalName()
792 << " Pptr: " << PSection->getExternalName()
793 << " Offset: " << FixupOffset << " Fixed Imm: " << FixedValue
794 << "\n";
795 };
796 (void)DumpReloc;
797
798 // Save relocation data for later writing.
799 LLVM_DEBUG(DumpReloc("A", &A));
800 Relocations.emplace_back(args&: PSection, args: &A, args&: ReferenceType, args&: ReferentType,
801 args: GOFF::RLD_ACT_Add, args&: FetchStore, args: FixupOffset, args: Length);
802 if (B) {
803 LLVM_DEBUG(DumpReloc("B", B));
804 Relocations.emplace_back(
805 args&: PSection, args&: B, args&: ReferenceType, args&: ReferentType, args: GOFF::RLD_ACT_Subtract,
806 args: GOFF::RLDFetchStore::RLD_FS_Fetch, args: FixupOffset, args: Length);
807 }
808}
809
810uint64_t GOFFObjectWriter::writeObject() {
811 uint64_t Size = GOFFWriter(OS, *Asm, RootSD, Relocations).writeObject();
812 return Size;
813}
814
815std::unique_ptr<MCObjectWriter>
816llvm::createGOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
817 raw_pwrite_stream &OS) {
818 return std::make_unique<GOFFObjectWriter>(args: std::move(MOTW), args&: OS);
819}
820