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/MCAssembler.h"
15#include "llvm/MC/MCGOFFAttributes.h"
16#include "llvm/MC/MCGOFFObjectWriter.h"
17#include "llvm/MC/MCSectionGOFF.h"
18#include "llvm/MC/MCSymbolGOFF.h"
19#include "llvm/MC/MCValue.h"
20#include "llvm/Support/Casting.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
272class GOFFWriter {
273 GOFFOstream OS;
274 MCAssembler &Asm;
275
276 void writeHeader();
277 void writeSymbol(const GOFFSymbol &Symbol);
278 void writeText(const MCSectionGOFF *MC);
279 void writeEnd();
280
281 void defineSectionSymbols(const MCSectionGOFF &Section);
282 void defineLabel(const MCSymbolGOFF &Symbol);
283 void defineSymbols();
284
285public:
286 GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm);
287 uint64_t writeObject();
288};
289} // namespace
290
291GOFFWriter::GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm)
292 : OS(OS), Asm(Asm) {}
293
294void GOFFWriter::defineSectionSymbols(const MCSectionGOFF &Section) {
295 if (Section.isSD()) {
296 GOFFSymbol SD(Section.getName(), Section.getOrdinal(),
297 Section.getSDAttributes());
298 writeSymbol(Symbol: SD);
299 }
300
301 if (Section.isED()) {
302 GOFFSymbol ED(Section.getName(), Section.getOrdinal(),
303 Section.getParent()->getOrdinal(), Section.getEDAttributes());
304 ED.SectionLength = Asm.getSectionAddressSize(Sec: Section);
305 writeSymbol(Symbol: ED);
306 }
307
308 if (Section.isPR()) {
309 MCSectionGOFF *Parent = Section.getParent();
310 GOFFSymbol PR(Section.getName(), Section.getOrdinal(), Parent->getOrdinal(),
311 Parent->getEDAttributes(), Section.getPRAttributes());
312 PR.SectionLength = Asm.getSectionAddressSize(Sec: Section);
313 if (Section.requiresNonZeroLength()) {
314 // We cannot have a zero-length section for data. If we do,
315 // artificially inflate it. Use 2 bytes to avoid odd alignments. Note:
316 // if this is ever changed, you will need to update the code in
317 // SystemZAsmPrinter::emitCEEMAIN and SystemZAsmPrinter::emitCELQMAIN to
318 // generate -1 if there is no ADA
319 if (!PR.SectionLength)
320 PR.SectionLength = 2;
321 }
322 writeSymbol(Symbol: PR);
323 }
324}
325
326void GOFFWriter::defineLabel(const MCSymbolGOFF &Symbol) {
327 MCSectionGOFF &Section = static_cast<MCSectionGOFF &>(Symbol.getSection());
328 GOFFSymbol LD(Symbol.getName(), Symbol.getIndex(), Section.getOrdinal(),
329 Section.getEDAttributes().NameSpace, Symbol.getLDAttributes());
330 if (Symbol.getADA())
331 LD.ADAEsdId = Symbol.getADA()->getOrdinal();
332 writeSymbol(Symbol: LD);
333}
334
335void GOFFWriter::defineSymbols() {
336 unsigned Ordinal = 0;
337 // Process all sections.
338 for (MCSection &S : Asm) {
339 auto &Section = cast<MCSectionGOFF>(Val&: S);
340 Section.setOrdinal(++Ordinal);
341 defineSectionSymbols(Section);
342 }
343
344 // Process all symbols
345 for (const MCSymbol &Sym : Asm.symbols()) {
346 if (Sym.isTemporary())
347 continue;
348 auto &Symbol = cast<MCSymbolGOFF>(Val: Sym);
349 if (Symbol.hasLDAttributes()) {
350 Symbol.setIndex(++Ordinal);
351 defineLabel(Symbol);
352 }
353 }
354}
355
356void GOFFWriter::writeHeader() {
357 OS.newRecord(Type: GOFF::RT_HDR);
358 OS.write_zeros(NumZeros: 1); // Reserved
359 OS.writebe<uint32_t>(Value: 0); // Target Hardware Environment
360 OS.writebe<uint32_t>(Value: 0); // Target Operating System Environment
361 OS.write_zeros(NumZeros: 2); // Reserved
362 OS.writebe<uint16_t>(Value: 0); // CCSID
363 OS.write_zeros(NumZeros: 16); // Character Set name
364 OS.write_zeros(NumZeros: 16); // Language Product Identifier
365 OS.writebe<uint32_t>(Value: 1); // Architecture Level
366 OS.writebe<uint16_t>(Value: 0); // Module Properties Length
367 OS.write_zeros(NumZeros: 6); // Reserved
368}
369
370void GOFFWriter::writeSymbol(const GOFFSymbol &Symbol) {
371 if (Symbol.Offset >= (((uint64_t)1) << 31))
372 report_fatal_error(reason: "ESD offset out of range");
373
374 // All symbol names are in EBCDIC.
375 SmallString<256> Name;
376 ConverterEBCDIC::convertToEBCDIC(Source: Symbol.Name, Result&: Name);
377
378 // Check length here since this number is technically signed but we need uint
379 // for writing to records.
380 if (Name.size() >= GOFF::MaxDataLength)
381 report_fatal_error(reason: "Symbol max name length exceeded");
382 uint16_t NameLength = Name.size();
383
384 OS.newRecord(Type: GOFF::RT_ESD);
385 OS.writebe<uint8_t>(Value: Symbol.SymbolType); // Symbol Type
386 OS.writebe<uint32_t>(Value: Symbol.EsdId); // ESDID
387 OS.writebe<uint32_t>(Value: Symbol.ParentEsdId); // Parent or Owning ESDID
388 OS.writebe<uint32_t>(Value: 0); // Reserved
389 OS.writebe<uint32_t>(
390 Value: static_cast<uint32_t>(Symbol.Offset)); // Offset or Address
391 OS.writebe<uint32_t>(Value: 0); // Reserved
392 OS.writebe<uint32_t>(Value: Symbol.SectionLength); // Length
393 OS.writebe<uint32_t>(Value: Symbol.EASectionEDEsdId); // Extended Attribute ESDID
394 OS.writebe<uint32_t>(Value: Symbol.EASectionOffset); // Extended Attribute Offset
395 OS.writebe<uint32_t>(Value: 0); // Reserved
396 OS.writebe<uint8_t>(Value: Symbol.NameSpace); // Name Space ID
397 OS.writebe<uint8_t>(Value: Symbol.SymbolFlags); // Flags
398 OS.writebe<uint8_t>(Value: Symbol.FillByteValue); // Fill-Byte Value
399 OS.writebe<uint8_t>(Value: 0); // Reserved
400 OS.writebe<uint32_t>(Value: Symbol.ADAEsdId); // ADA ESDID
401 OS.writebe<uint32_t>(Value: Symbol.SortKey); // Sort Priority
402 OS.writebe<uint64_t>(Value: 0); // Reserved
403 for (auto F : Symbol.BehavAttrs.Attr)
404 OS.writebe<uint8_t>(Value: F); // Behavioral Attributes
405 OS.writebe<uint16_t>(Value: NameLength); // Name Length
406 OS.write(Ptr: Name.data(), Size: NameLength); // Name
407}
408
409namespace {
410/// Adapter stream to write a text section.
411class TextStream : public raw_ostream {
412 /// The underlying GOFFOstream.
413 GOFFOstream &OS;
414
415 /// The buffer size is the maximum number of bytes in a TXT section.
416 static constexpr size_t BufferSize = GOFF::MaxDataLength;
417
418 /// Static allocated buffer for the stream, used by the raw_ostream class. The
419 /// buffer is sized to hold the payload of a logical TXT record.
420 char Buffer[BufferSize];
421
422 /// The offset for the next TXT record. This is equal to the number of bytes
423 /// written.
424 size_t Offset;
425
426 /// The Esdid of the GOFF section.
427 const uint32_t EsdId;
428
429 /// The record style.
430 const GOFF::ESDTextStyle RecordStyle;
431
432 /// See raw_ostream::write_impl.
433 void write_impl(const char *Ptr, size_t Size) override;
434
435 uint64_t current_pos() const override { return Offset; }
436
437public:
438 explicit TextStream(GOFFOstream &OS, uint32_t EsdId,
439 GOFF::ESDTextStyle RecordStyle)
440 : OS(OS), Offset(0), EsdId(EsdId), RecordStyle(RecordStyle) {
441 SetBuffer(BufferStart: Buffer, Size: sizeof(Buffer));
442 }
443
444 ~TextStream() { flush(); }
445};
446} // namespace
447
448void TextStream::write_impl(const char *Ptr, size_t Size) {
449 size_t WrittenLength = 0;
450
451 // We only have signed 32bits of offset.
452 if (Offset + Size > std::numeric_limits<int32_t>::max())
453 report_fatal_error(reason: "TXT section too large");
454
455 while (WrittenLength < Size) {
456 size_t ToWriteLength =
457 std::min(a: Size - WrittenLength, b: size_t(GOFF::MaxDataLength));
458
459 OS.newRecord(Type: GOFF::RT_TXT);
460 OS.writebe<uint8_t>(Value: GOFF::Flags(4, 4, RecordStyle)); // Text Record Style
461 OS.writebe<uint32_t>(Value: EsdId); // Element ESDID
462 OS.writebe<uint32_t>(Value: 0); // Reserved
463 OS.writebe<uint32_t>(Value: static_cast<uint32_t>(Offset)); // Offset
464 OS.writebe<uint32_t>(Value: 0); // Text Field True Length
465 OS.writebe<uint16_t>(Value: 0); // Text Encoding
466 OS.writebe<uint16_t>(Value: ToWriteLength); // Data Length
467 OS.write(Ptr: Ptr + WrittenLength, Size: ToWriteLength); // Data
468
469 WrittenLength += ToWriteLength;
470 Offset += ToWriteLength;
471 }
472}
473
474void GOFFWriter::writeText(const MCSectionGOFF *Section) {
475 // A BSS section contains only zeros, no need to write this.
476 if (Section->isBSS())
477 return;
478
479 TextStream S(OS, Section->getOrdinal(), Section->getTextStyle());
480 Asm.writeSectionData(OS&: S, Section);
481}
482
483void GOFFWriter::writeEnd() {
484 uint8_t F = GOFF::END_EPR_None;
485 uint8_t AMODE = 0;
486 uint32_t ESDID = 0;
487
488 // TODO Set Flags/AMODE/ESDID for entry point.
489
490 OS.newRecord(Type: GOFF::RT_END);
491 OS.writebe<uint8_t>(Value: GOFF::Flags(6, 2, F)); // Indicator flags
492 OS.writebe<uint8_t>(Value: AMODE); // AMODE
493 OS.write_zeros(NumZeros: 3); // Reserved
494 // The record count is the number of logical records. In principle, this value
495 // is available as OS.logicalRecords(). However, some tools rely on this field
496 // being zero.
497 OS.writebe<uint32_t>(Value: 0); // Record Count
498 OS.writebe<uint32_t>(Value: ESDID); // ESDID (of entry point)
499}
500
501uint64_t GOFFWriter::writeObject() {
502 writeHeader();
503
504 defineSymbols();
505
506 for (const MCSection &Section : Asm)
507 writeText(Section: static_cast<const MCSectionGOFF *>(&Section));
508
509 writeEnd();
510
511 // Make sure all records are written.
512 OS.finalizeRecord();
513
514 LLVM_DEBUG(dbgs() << "Wrote " << OS.getNumLogicalRecords()
515 << " logical records.");
516
517 return OS.getWrittenSize();
518}
519
520GOFFObjectWriter::GOFFObjectWriter(
521 std::unique_ptr<MCGOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS)
522 : TargetObjectWriter(std::move(MOTW)), OS(OS) {}
523
524GOFFObjectWriter::~GOFFObjectWriter() {}
525
526uint64_t GOFFObjectWriter::writeObject() {
527 uint64_t Size = GOFFWriter(OS, *Asm).writeObject();
528 return Size;
529}
530
531std::unique_ptr<MCObjectWriter>
532llvm::createGOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
533 raw_pwrite_stream &OS) {
534 return std::make_unique<GOFFObjectWriter>(args: std::move(MOTW), args&: OS);
535}
536