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, GOFF::ESDAlignment Alignment)
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(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, GOFF::ESDAlignment Alignment,
263 const GOFF::PRAttr &Attr)
264 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
265 SymbolType(GOFF::ESD_ST_PartReference), NameSpace(EDAttr.NameSpace) {
266 SymbolFlags.setRenameable(Attr.IsRenamable);
267 BehavAttrs.setExecutable(Attr.Executable);
268 BehavAttrs.setLinkageType(Attr.Linkage);
269 BehavAttrs.setBindingScope(Attr.BindingScope);
270 BehavAttrs.setAlignment(Alignment);
271 }
272
273 GOFFSymbol(StringRef Name, uint32_t EsdID, uint32_t ParentEsdID,
274 const GOFF::ERAttr &Attr)
275 : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
276 SymbolType(GOFF::ESD_ST_ExternalReference),
277 NameSpace(GOFF::ESD_NS_NormalName) {
278 BehavAttrs.setExecutable(Attr.Executable);
279 BehavAttrs.setBindingStrength(Attr.BindingStrength);
280 BehavAttrs.setLinkageType(Attr.Linkage);
281 BehavAttrs.setAmode(Attr.Amode);
282 BehavAttrs.setBindingScope(Attr.BindingScope);
283 BehavAttrs.setIndirectReference(Attr.IsIndirectReference);
284 }
285};
286
287class GOFFWriter {
288 GOFFOstream OS;
289 MCAssembler &Asm;
290 MCSectionGOFF *RootSD;
291
292 /// Saved relocation data collected in recordRelocations().
293 std::vector<GOFFRelocationEntry> &Relocations;
294
295public:
296 enum DwoMode {
297 AllSections,
298 NonDwoOnly,
299 DwoOnly,
300 };
301
302private:
303 const DwoMode Mode;
304
305 void writeHeader();
306 void writeSymbol(const GOFFSymbol &Symbol);
307 void writeText(const MCSectionGOFF *MC);
308 void writeRelocations();
309 void writeEnd();
310
311 void defineSectionSymbols(const MCSectionGOFF &Section);
312 void defineLabel(const MCSymbolGOFF &Symbol);
313 void defineExtern(const MCSymbolGOFF &Symbol);
314 void defineSymbols();
315
316public:
317 GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm, MCSectionGOFF *RootSD,
318 std::vector<GOFFRelocationEntry> &Relocations, DwoMode Mode);
319 uint64_t writeObject();
320};
321} // namespace
322
323GOFFWriter::GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm,
324 MCSectionGOFF *RootSD,
325 std::vector<GOFFRelocationEntry> &Relocations,
326 DwoMode Mode)
327 : OS(OS), Asm(Asm), RootSD(RootSD), Relocations(Relocations), Mode(Mode) {}
328
329namespace {
330bool isDwoSection(const MCSection &Section) {
331 StringRef Name = Section.getName();
332 return (Name.ends_with(Suffix: ".dwo") && Name.starts_with(Prefix: ".debug_")) ||
333 (Name.ends_with(Suffix: "_DWO") && Name.starts_with(Prefix: "D_"));
334}
335
336bool isSectionToSkip(const MCSection &Section, GOFFWriter::DwoMode Mode) {
337 if (Mode == GOFFWriter::DwoOnly) {
338 if (!isDwoSection(Section))
339 return true;
340 } else if (Mode == GOFFWriter::NonDwoOnly) {
341 if (isDwoSection(Section))
342 return true;
343 }
344 return false;
345}
346} // namespace
347
348void GOFFWriter::defineSectionSymbols(const MCSectionGOFF &Section) {
349 if (isSectionToSkip(Section, Mode))
350 return;
351
352 if (Section.isSD()) {
353 GOFFSymbol SD(Section.getExternalName(), Section.getOrdinal(),
354 Section.getSDAttributes());
355 writeSymbol(Symbol: SD);
356 }
357
358 if (Section.isED()) {
359 GOFFSymbol ED(Section.getExternalName(), Section.getOrdinal(),
360 Section.getParent()->getOrdinal(), Section.getEDAttributes(),
361 Section.getEDAlignment());
362 ED.SectionLength = Asm.getSectionAddressSize(Sec: Section);
363 writeSymbol(Symbol: ED);
364 }
365
366 if (Section.isPR()) {
367 MCSectionGOFF *Parent = Section.getParent();
368 GOFFSymbol PR(Section.getExternalName(), Section.getOrdinal(),
369 Parent->getOrdinal(), Parent->getEDAttributes(),
370 Parent->getEDAlignment(), Section.getPRAttributes());
371 PR.SectionLength = Asm.getSectionAddressSize(Sec: Section);
372 if (Section.requiresNonZeroLength()) {
373 // We cannot have a zero-length section for data. If we do,
374 // artificially inflate it. Use 2 bytes to avoid odd alignments. Note:
375 // if this is ever changed, you will need to update the code in
376 // SystemZAsmPrinter::emitCEEMAIN and SystemZAsmPrinter::emitCELQMAIN to
377 // generate -1 if there is no ADA
378 if (!PR.SectionLength)
379 PR.SectionLength = 2;
380 }
381 writeSymbol(Symbol: PR);
382 }
383}
384
385void GOFFWriter::defineLabel(const MCSymbolGOFF &Symbol) {
386 MCSectionGOFF &Section = static_cast<MCSectionGOFF &>(Symbol.getSection());
387 GOFFSymbol LD(Symbol.getExternalName(), Symbol.getIndex(),
388 Section.getOrdinal(), Section.getEDAttributes().NameSpace,
389 GOFF::LDAttr{.IsRenamable: false, .Executable: Symbol.getCodeData(),
390 .BindingStrength: Symbol.getBindingStrength(), .Linkage: Symbol.getLinkage(),
391 .Amode: GOFF::ESD_AMODE_64, .BindingScope: Symbol.getBindingScope()});
392 if (Symbol.getADA())
393 LD.ADAEsdId = Symbol.getADA()->getOrdinal();
394 LD.Offset = Asm.getSymbolOffset(S: Symbol);
395 writeSymbol(Symbol: LD);
396}
397
398void GOFFWriter::defineExtern(const MCSymbolGOFF &Symbol) {
399 if (Symbol.getCodeData() == GOFF::ESD_EXE_DATA) {
400 MCSectionGOFF *ED = Symbol.getADA()->getParent();
401 GOFFSymbol PR(Symbol.getExternalName(), Symbol.getIndex(), ED->getOrdinal(),
402 ED->getEDAttributes(), ED->getEDAlignment(),
403 GOFF::PRAttr{/*IsRenamable*/ false, .Executable: Symbol.getCodeData(),
404 .Linkage: Symbol.getLinkage(), .BindingScope: Symbol.getBindingScope(),
405 .SortKey: 0});
406 writeSymbol(Symbol: PR);
407 } else {
408 GOFFSymbol ER(Symbol.getExternalName(), Symbol.getIndex(),
409 RootSD->getOrdinal(),
410 GOFF::ERAttr{.IsIndirectReference: Symbol.isIndirect(), .Executable: Symbol.getCodeData(),
411 .BindingStrength: Symbol.getBindingStrength(), .Linkage: Symbol.getLinkage(),
412 .Amode: GOFF::ESD_AMODE_64, .BindingScope: Symbol.getBindingScope()});
413 writeSymbol(Symbol: ER);
414 }
415}
416
417void GOFFWriter::defineSymbols() {
418 unsigned Ordinal = 0;
419 // Process all sections.
420 for (MCSection &S : Asm) {
421 auto &Section = static_cast<MCSectionGOFF &>(S);
422 Section.setOrdinal(++Ordinal);
423 defineSectionSymbols(Section);
424 }
425
426 // Process all symbols
427 for (const MCSymbol &Sym : Asm.symbols()) {
428 if (Sym.isTemporary())
429 continue;
430 auto &Symbol = static_cast<const MCSymbolGOFF &>(Sym);
431 if (!Symbol.isDefined()) {
432 if (Mode != DwoOnly) {
433 Symbol.setIndex(++Ordinal);
434 defineExtern(Symbol);
435 }
436 } else {
437 if (isSectionToSkip(Section: Symbol.getSection(), Mode))
438 continue;
439 if (Symbol.isInEDSection()) {
440 Symbol.setIndex(++Ordinal);
441 defineLabel(Symbol);
442 } else {
443 // Symbol is in PR section, the symbol refers to the section.
444 Symbol.setIndex(Symbol.getSection().getOrdinal());
445 }
446 }
447 }
448}
449
450void GOFFWriter::writeHeader() {
451 OS.newRecord(Type: GOFF::RT_HDR);
452 OS.write_zeros(NumZeros: 1); // Reserved
453 OS.writebe<uint32_t>(Value: 0); // Target Hardware Environment
454 OS.writebe<uint32_t>(Value: 0); // Target Operating System Environment
455 OS.write_zeros(NumZeros: 2); // Reserved
456 OS.writebe<uint16_t>(Value: 0); // CCSID
457 OS.write_zeros(NumZeros: 16); // Character Set name
458 OS.write_zeros(NumZeros: 16); // Language Product Identifier
459 OS.writebe<uint32_t>(Value: 1); // Architecture Level
460 OS.writebe<uint16_t>(Value: 0); // Module Properties Length
461 OS.write_zeros(NumZeros: 6); // Reserved
462}
463
464void GOFFWriter::writeSymbol(const GOFFSymbol &Symbol) {
465 if (Symbol.Offset >= (((uint64_t)1) << 31))
466 report_fatal_error(reason: "ESD offset out of range");
467
468 // All symbol names are in EBCDIC.
469 SmallString<256> Name;
470 ConverterEBCDIC::convertToEBCDIC(Source: Symbol.Name, Result&: Name);
471
472 // Check length here since this number is technically signed but we need uint
473 // for writing to records.
474 if (Name.size() >= GOFF::MaxDataLength)
475 report_fatal_error(reason: "Symbol max name length exceeded");
476 uint16_t NameLength = Name.size();
477
478 OS.newRecord(Type: GOFF::RT_ESD);
479 OS.writebe<uint8_t>(Value: Symbol.SymbolType); // Symbol Type
480 OS.writebe<uint32_t>(Value: Symbol.EsdId); // ESDID
481 OS.writebe<uint32_t>(Value: Symbol.ParentEsdId); // Parent or Owning ESDID
482 OS.writebe<uint32_t>(Value: 0); // Reserved
483 OS.writebe<uint32_t>(
484 Value: static_cast<uint32_t>(Symbol.Offset)); // Offset or Address
485 OS.writebe<uint32_t>(Value: 0); // Reserved
486 OS.writebe<uint32_t>(Value: Symbol.SectionLength); // Length
487 OS.writebe<uint32_t>(Value: Symbol.EASectionEDEsdId); // Extended Attribute ESDID
488 OS.writebe<uint32_t>(Value: Symbol.EASectionOffset); // Extended Attribute Offset
489 OS.writebe<uint32_t>(Value: 0); // Reserved
490 OS.writebe<uint8_t>(Value: Symbol.NameSpace); // Name Space ID
491 OS.writebe<uint8_t>(Value: Symbol.SymbolFlags); // Flags
492 OS.writebe<uint8_t>(Value: Symbol.FillByteValue); // Fill-Byte Value
493 OS.writebe<uint8_t>(Value: 0); // Reserved
494 OS.writebe<uint32_t>(Value: Symbol.ADAEsdId); // ADA ESDID
495 OS.writebe<uint32_t>(Value: Symbol.SortKey); // Sort Priority
496 OS.writebe<uint64_t>(Value: 0); // Reserved
497 for (auto F : Symbol.BehavAttrs.Attr)
498 OS.writebe<uint8_t>(Value: F); // Behavioral Attributes
499 OS.writebe<uint16_t>(Value: NameLength); // Name Length
500 OS.write(Ptr: Name.data(), Size: NameLength); // Name
501}
502
503namespace {
504/// Adapter stream to write a text section.
505class TextStream : public raw_ostream {
506 /// The underlying GOFFOstream.
507 GOFFOstream &OS;
508
509 /// The buffer size is the maximum number of bytes in a TXT section.
510 static constexpr size_t BufferSize = GOFF::MaxDataLength;
511
512 /// Static allocated buffer for the stream, used by the raw_ostream class. The
513 /// buffer is sized to hold the payload of a logical TXT record.
514 char Buffer[BufferSize];
515
516 /// The offset for the next TXT record. This is equal to the number of bytes
517 /// written.
518 size_t Offset;
519
520 /// The Esdid of the GOFF section.
521 const uint32_t EsdId;
522
523 /// The record style.
524 const GOFF::ESDTextStyle RecordStyle;
525
526 /// See raw_ostream::write_impl.
527 void write_impl(const char *Ptr, size_t Size) override;
528
529 uint64_t current_pos() const override { return Offset; }
530
531public:
532 explicit TextStream(GOFFOstream &OS, uint32_t EsdId,
533 GOFF::ESDTextStyle RecordStyle)
534 : OS(OS), Offset(0), EsdId(EsdId), RecordStyle(RecordStyle) {
535 SetBuffer(BufferStart: Buffer, Size: sizeof(Buffer));
536 }
537
538 ~TextStream() override { flush(); }
539};
540} // namespace
541
542void TextStream::write_impl(const char *Ptr, size_t Size) {
543 size_t WrittenLength = 0;
544
545 // We only have signed 32bits of offset.
546 if (Offset + Size > std::numeric_limits<int32_t>::max())
547 report_fatal_error(reason: "TXT section too large");
548
549 while (WrittenLength < Size) {
550 size_t ToWriteLength =
551 std::min(a: Size - WrittenLength, b: size_t(GOFF::MaxDataLength));
552
553 OS.newRecord(Type: GOFF::RT_TXT);
554 OS.writebe<uint8_t>(Value: GOFF::Flags(4, 4, RecordStyle)); // Text Record Style
555 OS.writebe<uint32_t>(Value: EsdId); // Element ESDID
556 OS.writebe<uint32_t>(Value: 0); // Reserved
557 OS.writebe<uint32_t>(Value: static_cast<uint32_t>(Offset)); // Offset
558 OS.writebe<uint32_t>(Value: 0); // Text Field True Length
559 OS.writebe<uint16_t>(Value: 0); // Text Encoding
560 OS.writebe<uint16_t>(Value: ToWriteLength); // Data Length
561 OS.write(Ptr: Ptr + WrittenLength, Size: ToWriteLength); // Data
562
563 WrittenLength += ToWriteLength;
564 Offset += ToWriteLength;
565 }
566}
567
568void GOFFWriter::writeText(const MCSectionGOFF *Section) {
569 // A BSS section contains only zeros, no need to write this.
570 if (Section->isBSS())
571 return;
572
573 TextStream S(OS, Section->getOrdinal(), Section->getTextStyle());
574 Asm.writeSectionData(OS&: S, Section);
575}
576
577namespace {
578// RelocDataItemBuffer provides a static buffer for relocation data items.
579class RelocDataItemBuffer {
580 char Buffer[GOFF::MaxDataLength];
581 char *Ptr;
582
583public:
584 RelocDataItemBuffer() : Ptr(Buffer) {}
585 const char *data() { return Buffer; }
586 size_t size() { return Ptr - Buffer; }
587 void reset() { Ptr = Buffer; }
588 bool fits(size_t S) { return size() + S < GOFF::MaxDataLength; }
589 template <typename T> void writebe(T Val) {
590 assert(fits(sizeof(T)) && "Out-of-bounds write");
591 support::endian::write<T, llvm::endianness::big>(Ptr, Val);
592 Ptr += sizeof(T);
593 }
594};
595} // namespace
596
597void GOFFWriter::writeRelocations() {
598 // Set the IDs in the relocation entries.
599 for (auto &RelocEntry : Relocations) {
600 auto GetRptr = [](const MCSymbolGOFF *Sym) -> uint32_t {
601 if (Sym->isTemporary())
602 return static_cast<MCSectionGOFF &>(Sym->getSection())
603 .getBeginSymbol()
604 ->getIndex();
605 return Sym->getIndex();
606 };
607
608 RelocEntry.PEsdId = RelocEntry.Pptr->getOrdinal();
609 RelocEntry.REsdId = GetRptr(RelocEntry.Rptr);
610 }
611
612 // Sort relocation data items by the P pointer to save space.
613 std::sort(
614 first: Relocations.begin(), last: Relocations.end(),
615 comp: [](const GOFFRelocationEntry &Left, const GOFFRelocationEntry &Right) {
616 return std::tie(args: Left.PEsdId, args: Left.REsdId, args: Left.POffset) <
617 std::tie(args: Right.PEsdId, args: Right.REsdId, args: Right.POffset);
618 });
619
620 // Construct the compressed relocation data items, and write them out.
621 RelocDataItemBuffer Buffer;
622 for (auto I = Relocations.begin(), E = Relocations.end(); I != E;) {
623 Buffer.reset();
624
625 uint32_t PrevResdId = -1;
626 uint32_t PrevPesdId = -1;
627 uint64_t PrevPOffset = -1;
628 for (; I != E; ++I) {
629 const GOFFRelocationEntry &Rel = *I;
630
631 bool SameREsdId = (Rel.REsdId == PrevResdId);
632 bool SamePEsdId = (Rel.PEsdId == PrevPesdId);
633 bool SamePOffset = (Rel.POffset == PrevPOffset);
634 bool EightByteOffset = ((Rel.POffset >> 32) & 0xffffffff);
635
636 // Calculate size of relocation data item, and check if it still fits into
637 // the record.
638 size_t ItemSize = 8; // Smallest size of a relocation data item.
639 if (!SameREsdId)
640 ItemSize += 4;
641 if (!SamePEsdId)
642 ItemSize += 4;
643 if (!SamePOffset)
644 ItemSize += (EightByteOffset ? 8 : 4);
645 if (!Buffer.fits(S: ItemSize))
646 break;
647
648 GOFF::Flags RelocFlags[6];
649 RelocFlags[0].set(BitIndex: 0, Length: 1, NewValue: SameREsdId);
650 RelocFlags[0].set(BitIndex: 1, Length: 1, NewValue: SamePEsdId);
651 RelocFlags[0].set(BitIndex: 2, Length: 1, NewValue: SamePOffset);
652 RelocFlags[0].set(BitIndex: 6, Length: 1, NewValue: EightByteOffset);
653
654 RelocFlags[1].set(BitIndex: 0, Length: 4, NewValue: Rel.ReferenceType);
655 RelocFlags[1].set(BitIndex: 4, Length: 4, NewValue: Rel.ReferentType);
656
657 RelocFlags[2].set(BitIndex: 0, Length: 7, NewValue: Rel.Action);
658 RelocFlags[2].set(BitIndex: 7, Length: 1, NewValue: Rel.FetchStore);
659
660 RelocFlags[4].set(BitIndex: 0, Length: 8, NewValue: Rel.TargetLength);
661
662 for (auto F : RelocFlags)
663 Buffer.writebe<uint8_t>(Val: F);
664 Buffer.writebe<uint16_t>(Val: 0); // Reserved.
665 if (!SameREsdId)
666 Buffer.writebe<uint32_t>(Val: Rel.REsdId);
667 if (!SamePEsdId)
668 Buffer.writebe<uint32_t>(Val: Rel.PEsdId);
669 if (!SamePOffset) {
670 if (EightByteOffset)
671 Buffer.writebe<uint64_t>(Val: Rel.POffset);
672 else
673 Buffer.writebe<uint32_t>(Val: Rel.POffset);
674 }
675
676 PrevResdId = Rel.REsdId;
677 PrevPesdId = Rel.PEsdId;
678 PrevPOffset = Rel.POffset;
679 }
680
681 OS.newRecord(Type: GOFF::RT_RLD);
682 OS.writebe<uint8_t>(Value: 0); // Reserved.
683 OS.writebe<uint16_t>(Value: Buffer.size()); // Length (of the relocation data).
684 OS.write(Ptr: Buffer.data(), Size: Buffer.size()); // Relocation Directory Data Items.
685 }
686}
687
688void GOFFWriter::writeEnd() {
689 uint8_t F = GOFF::END_EPR_None;
690 uint8_t AMODE = 0;
691 uint32_t ESDID = 0;
692
693 // TODO Set Flags/AMODE/ESDID for entry point.
694
695 OS.newRecord(Type: GOFF::RT_END);
696 OS.writebe<uint8_t>(Value: GOFF::Flags(6, 2, F)); // Indicator flags
697 OS.writebe<uint8_t>(Value: AMODE); // AMODE
698 OS.write_zeros(NumZeros: 3); // Reserved
699 // The record count is the number of logical records. In principle, this value
700 // is available as OS.logicalRecords(). However, some tools rely on this field
701 // being zero.
702 OS.writebe<uint32_t>(Value: 0); // Record Count
703 OS.writebe<uint32_t>(Value: ESDID); // ESDID (of entry point)
704}
705
706uint64_t GOFFWriter::writeObject() {
707 writeHeader();
708
709 defineSymbols();
710
711 for (const MCSection &Section : Asm)
712 writeText(Section: static_cast<const MCSectionGOFF *>(&Section));
713
714 // Do not write relocations into the dwo file.
715 if (Mode != GOFFWriter::DwoOnly)
716 writeRelocations();
717
718 writeEnd();
719
720 // Make sure all records are written.
721 OS.finalizeRecord();
722
723 LLVM_DEBUG(dbgs() << "Wrote " << OS.getNumLogicalRecords()
724 << " logical records.");
725
726 return OS.getWrittenSize();
727}
728
729GOFFObjectWriter::GOFFObjectWriter(
730 std::unique_ptr<MCGOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS)
731 : TargetObjectWriter(std::move(MOTW)), OS(OS) {}
732
733GOFFObjectWriter::GOFFObjectWriter(
734 std::unique_ptr<MCGOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS,
735 raw_pwrite_stream &DwoOS)
736 : TargetObjectWriter(std::move(MOTW)), OS(OS), DwoOS(&DwoOS) {}
737
738GOFFObjectWriter::~GOFFObjectWriter() = default;
739
740void GOFFObjectWriter::reset() {
741 Relocations.clear();
742 RootSD = nullptr;
743 MCObjectWriter::reset();
744}
745
746void GOFFObjectWriter::recordRelocation(const MCFragment &F,
747 const MCFixup &Fixup, MCValue Target,
748 uint64_t &FixedValue) {
749 const MCFixupKindInfo &FKI =
750 Asm->getBackend().getFixupKindInfo(Kind: Fixup.getKind());
751 const uint32_t Length = FKI.TargetSize / 8;
752 assert(FKI.TargetSize % 8 == 0 && "Target Size not multiple of 8");
753 const uint64_t FixupOffset = Asm->getFragmentOffset(F) + Fixup.getOffset();
754
755 unsigned RelocType = TargetObjectWriter->getRelocType(Target, Fixup);
756
757 const MCSectionGOFF *PSection = static_cast<MCSectionGOFF *>(F.getParent());
758 const auto &A = *static_cast<const MCSymbolGOFF *>(Target.getAddSym());
759 const MCSymbolGOFF *B = static_cast<const MCSymbolGOFF *>(Target.getSubSym());
760 if (RelocType == MCGOFFObjectTargetWriter::Reloc_Type_RICon) {
761 if (A.isUndefined()) {
762 Asm->reportError(
763 L: Fixup.getLoc(),
764 Msg: Twine("symbol ")
765 .concat(Suffix: A.getExternalName())
766 .concat(Suffix: " must be defined for a relative immediate relocation"));
767 return;
768 }
769 if (&A.getSection() != PSection) {
770 MCSectionGOFF &GOFFSection = static_cast<MCSectionGOFF &>(A.getSection());
771 Asm->reportError(L: Fixup.getLoc(),
772 Msg: Twine("relative immediate relocation section mismatch: ")
773 .concat(Suffix: GOFFSection.getExternalName())
774 .concat(Suffix: " of symbol ")
775 .concat(Suffix: A.getExternalName())
776 .concat(Suffix: " <-> ")
777 .concat(Suffix: PSection->getExternalName()));
778 return;
779 }
780 if (B) {
781 Asm->reportError(
782 L: Fixup.getLoc(),
783 Msg: Twine("subtractive symbol ")
784 .concat(Suffix: B->getExternalName())
785 .concat(Suffix: " not supported for a relative immediate relocation"));
786 return;
787 }
788 FixedValue = Asm->getSymbolOffset(S: A) - FixupOffset + Target.getConstant();
789 return;
790 }
791 FixedValue = Target.getConstant();
792
793 // The symbol only has a section-relative offset if it is a temporary symbol.
794 FixedValue += A.isTemporary() ? Asm->getSymbolOffset(S: A) : 0;
795 A.setUsedInReloc();
796 if (B) {
797 FixedValue -= B->isTemporary() ? Asm->getSymbolOffset(S: *B) : 0;
798 B->setUsedInReloc();
799 }
800
801 // UseQCon causes class offsets versus absolute addresses to be used. This
802 // is analogous to using QCONs in older OBJ object file format.
803 bool UseQCon = RelocType == MCGOFFObjectTargetWriter::Reloc_Type_QCon;
804
805 GOFF::RLDFetchStore FetchStore =
806 (RelocType == MCGOFFObjectTargetWriter::Reloc_Type_RCon ||
807 RelocType == MCGOFFObjectTargetWriter::Reloc_Type_VCon)
808 ? GOFF::RLDFetchStore::RLD_FS_Store
809 : GOFF::RLDFetchStore::RLD_FS_Fetch;
810 assert((FetchStore == GOFF::RLDFetchStore::RLD_FS_Fetch || B == nullptr) &&
811 "No dependent relocations expected");
812
813 enum GOFF::RLDReferenceType ReferenceType = GOFF::RLD_RT_RAddress;
814 enum GOFF::RLDReferentType ReferentType = GOFF::RLD_RO_Label;
815 if (UseQCon) {
816 ReferenceType = GOFF::RLD_RT_ROffset;
817 ReferentType = GOFF::RLD_RO_Class;
818 }
819 if (RelocType == MCGOFFObjectTargetWriter::Reloc_Type_RCon)
820 ReferenceType = GOFF::RLD_RT_RTypeConstant;
821
822 auto DumpReloc = [&PSection, &ReferenceType, &FixupOffset,
823 &FixedValue](const char *N, const MCSymbolGOFF *Sym) {
824 const char *Con;
825 switch (ReferenceType) {
826 case GOFF::RLDReferenceType::RLD_RT_RAddress:
827 Con = "ACon";
828 break;
829 case GOFF::RLDReferenceType::RLD_RT_ROffset:
830 Con = "QCon";
831 break;
832 case GOFF::RLDReferenceType::RLD_RT_RTypeConstant:
833 Con = "VCon";
834 break;
835 default:
836 Con = "(unknown)";
837 }
838 dbgs() << "Reloc " << N << ": " << Con
839 << " Rptr: " << Sym->getExternalName()
840 << " Pptr: " << PSection->getExternalName()
841 << " Offset: " << FixupOffset << " Fixed Imm: " << FixedValue
842 << "\n";
843 };
844 (void)DumpReloc;
845
846 // Save relocation data for later writing.
847 LLVM_DEBUG(DumpReloc("A", &A));
848 Relocations.emplace_back(args&: PSection, args: &A, args&: ReferenceType, args&: ReferentType,
849 args: GOFF::RLD_ACT_Add, args&: FetchStore, args: FixupOffset, args: Length);
850 if (B) {
851 LLVM_DEBUG(DumpReloc("B", B));
852 Relocations.emplace_back(
853 args&: PSection, args&: B, args&: ReferenceType, args&: ReferentType, args: GOFF::RLD_ACT_Subtract,
854 args: GOFF::RLDFetchStore::RLD_FS_Fetch, args: FixupOffset, args: Length);
855 }
856}
857
858uint64_t GOFFObjectWriter::writeObject() {
859 uint64_t Size = 0;
860 if (DwoOS)
861 Size += GOFFWriter(*DwoOS, *Asm, RootSD, Relocations, GOFFWriter::DwoOnly)
862 .writeObject();
863 Size += GOFFWriter(OS, *Asm, RootSD, Relocations,
864 DwoOS ? GOFFWriter::NonDwoOnly : GOFFWriter::AllSections)
865 .writeObject();
866 return Size;
867}
868
869std::unique_ptr<MCObjectWriter>
870llvm::createGOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
871 raw_pwrite_stream &OS) {
872 return std::make_unique<GOFFObjectWriter>(args: std::move(MOTW), args&: OS);
873}
874
875std::unique_ptr<MCObjectWriter>
876llvm::createGOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
877 raw_pwrite_stream &OS, raw_pwrite_stream &DwoOS) {
878 return std::make_unique<GOFFObjectWriter>(args: std::move(MOTW), args&: OS, args&: DwoOS);
879}
880