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