1 //===- lib/MC/MCContext.cpp - Machine Code Context ------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCContext.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/MC/MCAsmInfo.h"
14 #include "llvm/MC/MCDwarf.h"
15 #include "llvm/MC/MCLabel.h"
16 #include "llvm/MC/MCObjectFileInfo.h"
17 #include "llvm/MC/MCRegisterInfo.h"
18 #include "llvm/MC/MCSectionCOFF.h"
19 #include "llvm/MC/MCSectionELF.h"
20 #include "llvm/MC/MCSectionMachO.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/MC/MCSymbol.h"
23 #include "llvm/Support/ELF.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/FileSystem.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/Signals.h"
28 #include "llvm/Support/SourceMgr.h"
33 MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
34 const MCObjectFileInfo *mofi, const SourceMgr *mgr,
36 : SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi), Allocator(),
37 Symbols(Allocator), UsedNames(Allocator), NextUniqueID(0),
38 CurrentDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0), DwarfLocSeen(false),
39 GenDwarfForAssembly(false), GenDwarfFileNumber(0), DwarfVersion(4),
40 AllowTemporaryLabels(true), DwarfCompileUnitID(0),
41 AutoReset(DoAutoReset) {
43 std::error_code EC = llvm::sys::fs::current_path(CompilationDir);
45 CompilationDir.clear();
47 SecureLogFile = getenv("AS_SECURE_LOG_FILE");
49 SecureLogUsed = false;
51 if (SrcMgr && SrcMgr->getNumBuffers())
53 SrcMgr->getMemoryBuffer(SrcMgr->getMainFileID())->getBufferIdentifier();
56 MCContext::~MCContext() {
61 // NOTE: The symbols are all allocated out of a bump pointer allocator,
62 // we don't need to free them here.
64 // If the stream for the .secure_log_unique directive was created free it.
65 delete (raw_ostream*)SecureLog;
68 //===----------------------------------------------------------------------===//
69 // Module Lifetime Management
70 //===----------------------------------------------------------------------===//
72 void MCContext::reset() {
77 CompilationDir.clear();
79 MCDwarfLineTablesCUMap.clear();
80 SectionStartEndSyms.clear();
81 MCGenDwarfLabelEntries.clear();
82 DwarfDebugFlags = StringRef();
83 DwarfCompileUnitID = 0;
84 CurrentDwarfLoc = MCDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0);
86 MachOUniquingMap.clear();
87 ELFUniquingMap.clear();
88 COFFUniquingMap.clear();
91 AllowTemporaryLabels = true;
93 GenDwarfForAssembly = false;
94 GenDwarfFileNumber = 0;
97 //===----------------------------------------------------------------------===//
98 // Symbol Manipulation
99 //===----------------------------------------------------------------------===//
101 MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
102 SmallString<128> NameSV;
103 StringRef NameRef = Name.toStringRef(NameSV);
105 assert(!NameRef.empty() && "Normal symbols cannot be unnamed!");
107 MCSymbol *&Sym = Symbols[NameRef];
109 Sym = CreateSymbol(NameRef);
114 MCSymbol *MCContext::getOrCreateSectionSymbol(const MCSectionELF &Section) {
115 MCSymbol *&Sym = SectionSymbols[&Section];
119 StringRef Name = Section.getSectionName();
121 MCSymbol *&OldSym = Symbols[Name];
122 if (OldSym && OldSym->isUndefined()) {
127 auto NameIter = UsedNames.insert(std::make_pair(Name, true)).first;
128 Sym = new (*this) MCSymbol(NameIter->getKey(), /*isTemporary*/ false);
136 MCSymbol *MCContext::getOrCreateFrameAllocSymbol(StringRef FuncName,
138 return GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
139 "$frame_escape_" + Twine(Idx));
142 MCSymbol *MCContext::CreateSymbol(StringRef Name) {
143 // Determine whether this is an assembler temporary or normal label, if used.
144 bool isTemporary = false;
145 if (AllowTemporaryLabels)
146 isTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
148 auto NameEntry = UsedNames.insert(std::make_pair(Name, true));
149 if (!NameEntry.second) {
150 assert(isTemporary && "Cannot rename non-temporary symbols");
151 SmallString<128> NewName = Name;
153 NewName.resize(Name.size());
154 raw_svector_ostream(NewName) << NextUniqueID++;
155 NameEntry = UsedNames.insert(std::make_pair(NewName, true));
156 } while (!NameEntry.second);
159 // Ok, the entry doesn't already exist. Have the MCSymbol object itself refer
160 // to the copy of the string that is embedded in the UsedNames entry.
162 new (*this) MCSymbol(NameEntry.first->getKey(), isTemporary);
167 MCSymbol *MCContext::createTempSymbol(const Twine &Name) {
168 SmallString<128> NameSV;
169 raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
170 return CreateSymbol(NameSV);
173 MCSymbol *MCContext::CreateLinkerPrivateTempSymbol() {
174 SmallString<128> NameSV;
175 raw_svector_ostream(NameSV)
176 << MAI->getLinkerPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
177 return CreateSymbol(NameSV);
180 MCSymbol *MCContext::CreateTempSymbol() {
181 SmallString<128> NameSV;
182 raw_svector_ostream(NameSV)
183 << MAI->getPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
184 return CreateSymbol(NameSV);
187 unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
188 MCLabel *&Label = Instances[LocalLabelVal];
190 Label = new (*this) MCLabel(0);
191 return Label->incInstance();
194 unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
195 MCLabel *&Label = Instances[LocalLabelVal];
197 Label = new (*this) MCLabel(0);
198 return Label->getInstance();
201 MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
203 MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
205 Sym = CreateTempSymbol();
209 MCSymbol *MCContext::CreateDirectionalLocalSymbol(unsigned LocalLabelVal) {
210 unsigned Instance = NextInstance(LocalLabelVal);
211 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
214 MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
216 unsigned Instance = GetInstance(LocalLabelVal);
219 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
222 MCSymbol *MCContext::LookupSymbol(const Twine &Name) const {
223 SmallString<128> NameSV;
224 StringRef NameRef = Name.toStringRef(NameSV);
225 return Symbols.lookup(NameRef);
228 //===----------------------------------------------------------------------===//
229 // Section Management
230 //===----------------------------------------------------------------------===//
232 const MCSectionMachO *
233 MCContext::getMachOSection(StringRef Segment, StringRef Section,
234 unsigned TypeAndAttributes, unsigned Reserved2,
235 SectionKind Kind, const char *BeginSymName) {
237 // We unique sections by their segment/section pair. The returned section
238 // may not have the same flags as the requested section, if so this should be
239 // diagnosed by the client as an error.
241 // Form the name to look up.
242 SmallString<64> Name;
247 // Do the lookup, if we have a hit, return it.
248 const MCSectionMachO *&Entry = MachOUniquingMap[Name];
252 MCSymbol *Begin = nullptr;
254 Begin = createTempSymbol(BeginSymName);
256 // Otherwise, return a new section.
257 return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
258 Reserved2, Kind, Begin);
261 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
263 const char *BeginSymName) {
264 return getELFSection(Section, Type, Flags, 0, "", BeginSymName);
267 void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
269 if (const MCSymbol *Group = Section->getGroup())
270 GroupName = Group->getName();
272 ELFUniquingMap.erase(SectionGroupPair(Section->getSectionName(), GroupName));
274 ELFUniquingMap.insert(std::make_pair(SectionGroupPair(Name, GroupName),
276 StringRef CachedName = I->first.first;
277 const_cast<MCSectionELF*>(Section)->setSectionName(CachedName);
280 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
281 unsigned Flags, unsigned EntrySize,
282 StringRef Group, bool Unique,
283 const char *BeginSymName) {
284 // Do the lookup, if we have a hit, return it.
285 auto IterBool = ELFUniquingMap.insert(
286 std::make_pair(SectionGroupPair(Section, Group), nullptr));
287 auto &Entry = *IterBool.first;
288 if (!IterBool.second && !Unique)
291 MCSymbol *GroupSym = nullptr;
293 GroupSym = GetOrCreateSymbol(Group);
295 StringRef CachedName = Entry.first.first;
298 if (Flags & ELF::SHF_EXECINSTR)
299 Kind = SectionKind::getText();
301 Kind = SectionKind::getReadOnly();
303 MCSymbol *Begin = nullptr;
305 Begin = createTempSymbol(BeginSymName);
307 MCSectionELF *Result = new (*this) MCSectionELF(
308 CachedName, Type, Flags, Kind, EntrySize, GroupSym, Unique, Begin);
310 Entry.second = Result;
314 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
315 unsigned Flags, unsigned EntrySize,
317 const char *BeginSymName) {
318 return getELFSection(Section, Type, Flags, EntrySize, Group, false,
322 const MCSectionELF *MCContext::CreateELFGroupSection() {
323 MCSectionELF *Result = new (*this)
324 MCSectionELF(".group", ELF::SHT_GROUP, 0, SectionKind::getReadOnly(), 4,
325 nullptr, false, nullptr);
329 const MCSectionCOFF *
330 MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
331 SectionKind Kind, StringRef COMDATSymName,
332 int Selection, const char *BeginSymName) {
333 // Do the lookup, if we have a hit, return it.
335 SectionGroupTriple T(Section, COMDATSymName, Selection);
336 auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
337 auto Iter = IterBool.first;
338 if (!IterBool.second)
341 MCSymbol *COMDATSymbol = nullptr;
342 if (!COMDATSymName.empty())
343 COMDATSymbol = GetOrCreateSymbol(COMDATSymName);
345 MCSymbol *Begin = nullptr;
347 Begin = createTempSymbol(BeginSymName);
349 StringRef CachedName = std::get<0>(Iter->first);
350 MCSectionCOFF *Result = new (*this) MCSectionCOFF(
351 CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);
353 Iter->second = Result;
357 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
358 unsigned Characteristics,
360 const char *BeginSymName) {
361 return getCOFFSection(Section, Characteristics, Kind, "", 0, BeginSymName);
364 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
365 SectionGroupTriple T(Section, "", 0);
366 auto Iter = COFFUniquingMap.find(T);
367 if (Iter == COFFUniquingMap.end())
372 const MCSectionCOFF *
373 MCContext::getAssociativeCOFFSection(const MCSectionCOFF *Sec,
374 const MCSymbol *KeySym) {
375 // Return the normal section if we don't have to be associative.
379 // Make an associative section with the same name and kind as the normal
381 unsigned Characteristics =
382 Sec->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT;
383 return getCOFFSection(Sec->getSectionName(), Characteristics, Sec->getKind(),
385 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE);
388 //===----------------------------------------------------------------------===//
390 //===----------------------------------------------------------------------===//
392 /// GetDwarfFile - takes a file name an number to place in the dwarf file and
393 /// directory tables. If the file number has already been allocated it is an
394 /// error and zero is returned and the client reports the error, else the
395 /// allocated file number is returned. The file numbers may be in any order.
396 unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
397 unsigned FileNumber, unsigned CUID) {
398 MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
399 return Table.getFile(Directory, FileName, FileNumber);
402 /// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
403 /// currently is assigned and false otherwise.
404 bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
405 const SmallVectorImpl<MCDwarfFile>& MCDwarfFiles = getMCDwarfFiles(CUID);
406 if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
409 return !MCDwarfFiles[FileNumber].Name.empty();
412 /// finalizeDwarfSections - Emit end symbols for each non-empty code section.
413 /// Also remove empty sections from SectionStartEndSyms, to avoid generating
414 /// useless debug info for them.
415 void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
416 MCContext &context = MCOS.getContext();
418 auto sec = SectionStartEndSyms.begin();
419 while (sec != SectionStartEndSyms.end()) {
420 assert(sec->second.first && "Start symbol must be set by now");
421 MCOS.SwitchSection(sec->first);
422 if (MCOS.mayHaveInstructions()) {
423 MCSymbol *SectionEndSym = context.CreateTempSymbol();
424 MCOS.EmitLabel(SectionEndSym);
425 sec->second.second = SectionEndSym;
428 MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
430 sec = SectionStartEndSyms.erase(to_erase);
435 void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
436 // If we have a source manager and a location, use it. Otherwise just
437 // use the generic report_fatal_error().
438 if (!SrcMgr || Loc == SMLoc())
439 report_fatal_error(Msg, false);
441 // Use the source manager to print the message.
442 SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
444 // If we reached here, we are failing ungracefully. Run the interrupt handlers
445 // to make sure any special cleanups get done, in particular that we remove
446 // files registered with RemoveFileOnSignal.
447 sys::RunInterruptHandlers();