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),
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, false);
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 "$frame_escape_" + Twine(Idx));
142 MCSymbol *MCContext::getOrCreateParentFrameOffsetSymbol(StringRef FuncName) {
143 return GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
144 "$parent_frame_offset");
147 MCSymbol *MCContext::CreateSymbol(StringRef Name, bool AlwaysAddSuffix) {
148 // Determine whether this is an assembler temporary or normal label, if used.
149 bool IsTemporary = false;
150 if (AllowTemporaryLabels)
151 IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
153 if (IsTemporary && AlwaysAddSuffix && !UseNamesOnTempLabels)
154 return new (*this) MCSymbol("", true);
156 SmallString<128> NewName = Name;
157 bool AddSuffix = AlwaysAddSuffix;
158 unsigned &NextUniqueID = NextID[Name];
161 NewName.resize(Name.size());
162 raw_svector_ostream(NewName) << NextUniqueID++;
164 auto NameEntry = UsedNames.insert(std::make_pair(NewName, true));
165 if (NameEntry.second) {
166 // Ok, we found a name. Have the MCSymbol object itself refer to the copy
167 // of the string that is embedded in the UsedNames entry.
169 new (*this) MCSymbol(NameEntry.first->getKey(), IsTemporary);
172 assert(IsTemporary && "Cannot rename non-temporary symbols");
175 llvm_unreachable("Infinite loop");
178 MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix) {
179 SmallString<128> NameSV;
180 raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
181 return CreateSymbol(NameSV, AlwaysAddSuffix);
184 MCSymbol *MCContext::CreateLinkerPrivateTempSymbol() {
185 SmallString<128> NameSV;
186 raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << "tmp";
187 return CreateSymbol(NameSV, true);
190 MCSymbol *MCContext::CreateTempSymbol() {
191 return createTempSymbol("tmp", true);
194 unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
195 MCLabel *&Label = Instances[LocalLabelVal];
197 Label = new (*this) MCLabel(0);
198 return Label->incInstance();
201 unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
202 MCLabel *&Label = Instances[LocalLabelVal];
204 Label = new (*this) MCLabel(0);
205 return Label->getInstance();
208 MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
210 MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
212 Sym = CreateTempSymbol();
216 MCSymbol *MCContext::CreateDirectionalLocalSymbol(unsigned LocalLabelVal) {
217 unsigned Instance = NextInstance(LocalLabelVal);
218 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
221 MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
223 unsigned Instance = GetInstance(LocalLabelVal);
226 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
229 MCSymbol *MCContext::LookupSymbol(const Twine &Name) const {
230 SmallString<128> NameSV;
231 StringRef NameRef = Name.toStringRef(NameSV);
232 return Symbols.lookup(NameRef);
235 //===----------------------------------------------------------------------===//
236 // Section Management
237 //===----------------------------------------------------------------------===//
239 const MCSectionMachO *
240 MCContext::getMachOSection(StringRef Segment, StringRef Section,
241 unsigned TypeAndAttributes, unsigned Reserved2,
242 SectionKind Kind, const char *BeginSymName) {
244 // We unique sections by their segment/section pair. The returned section
245 // may not have the same flags as the requested section, if so this should be
246 // diagnosed by the client as an error.
248 // Form the name to look up.
249 SmallString<64> Name;
254 // Do the lookup, if we have a hit, return it.
255 const MCSectionMachO *&Entry = MachOUniquingMap[Name];
259 MCSymbol *Begin = nullptr;
261 Begin = createTempSymbol(BeginSymName, false);
263 // Otherwise, return a new section.
264 return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
265 Reserved2, Kind, Begin);
268 void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
270 if (const MCSymbol *Group = Section->getGroup())
271 GroupName = Group->getName();
273 unsigned UniqueID = Section->getUniqueID();
274 ELFUniquingMap.erase(
275 ELFSectionKey{Section->getSectionName(), GroupName, UniqueID});
276 auto I = ELFUniquingMap.insert(std::make_pair(
277 ELFSectionKey{Name, GroupName, UniqueID},
279 StringRef CachedName = I->first.SectionName;
280 const_cast<MCSectionELF*>(Section)->setSectionName(CachedName);
284 MCContext::createELFRelSection(StringRef Name, unsigned Type, unsigned Flags,
285 unsigned EntrySize, const MCSymbol *Group,
286 const MCSectionELF *Associated) {
287 StringMap<bool>::iterator I;
289 std::tie(I, Inserted) = ELFRelSecNames.insert(std::make_pair(Name, true));
292 MCSectionELF(I->getKey(), Type, Flags, SectionKind::getReadOnly(),
293 EntrySize, Group, true, nullptr, Associated);
296 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
297 unsigned Flags, unsigned EntrySize,
298 StringRef Group, unsigned UniqueID,
299 const char *BeginSymName) {
300 MCSymbol *GroupSym = nullptr;
302 GroupSym = GetOrCreateSymbol(Group);
304 return getELFSection(Section, Type, Flags, EntrySize, GroupSym, UniqueID,
305 BeginSymName, nullptr);
308 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
309 unsigned Flags, unsigned EntrySize,
310 const MCSymbol *GroupSym,
312 const char *BeginSymName,
313 const MCSectionELF *Associated) {
314 StringRef Group = "";
316 Group = GroupSym->getName();
317 // Do the lookup, if we have a hit, return it.
318 auto IterBool = ELFUniquingMap.insert(
319 std::make_pair(ELFSectionKey{Section, Group, UniqueID}, nullptr));
320 auto &Entry = *IterBool.first;
321 if (!IterBool.second)
324 StringRef CachedName = Entry.first.SectionName;
327 if (Flags & ELF::SHF_EXECINSTR)
328 Kind = SectionKind::getText();
330 Kind = SectionKind::getReadOnly();
332 MCSymbol *Begin = nullptr;
334 Begin = createTempSymbol(BeginSymName, false);
336 MCSectionELF *Result =
337 new (*this) MCSectionELF(CachedName, Type, Flags, Kind, EntrySize,
338 GroupSym, UniqueID, Begin, Associated);
339 Entry.second = Result;
343 const MCSectionELF *MCContext::createELFGroupSection(const MCSymbol *Group) {
344 MCSectionELF *Result = new (*this)
345 MCSectionELF(".group", ELF::SHT_GROUP, 0, SectionKind::getReadOnly(), 4,
346 Group, ~0, nullptr, nullptr);
350 const MCSectionCOFF *
351 MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
352 SectionKind Kind, StringRef COMDATSymName,
353 int Selection, const char *BeginSymName) {
354 MCSymbol *COMDATSymbol = nullptr;
355 if (!COMDATSymName.empty()) {
356 COMDATSymbol = GetOrCreateSymbol(COMDATSymName);
357 COMDATSymName = COMDATSymbol->getName();
360 // Do the lookup, if we have a hit, return it.
361 COFFSectionKey T{Section, COMDATSymName, Selection};
362 auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
363 auto Iter = IterBool.first;
364 if (!IterBool.second)
367 MCSymbol *Begin = nullptr;
369 Begin = createTempSymbol(BeginSymName, false);
371 StringRef CachedName = Iter->first.SectionName;
372 MCSectionCOFF *Result = new (*this) MCSectionCOFF(
373 CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);
375 Iter->second = Result;
379 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
380 unsigned Characteristics,
382 const char *BeginSymName) {
383 return getCOFFSection(Section, Characteristics, Kind, "", 0, BeginSymName);
386 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
387 COFFSectionKey T{Section, "", 0};
388 auto Iter = COFFUniquingMap.find(T);
389 if (Iter == COFFUniquingMap.end())
394 const MCSectionCOFF *
395 MCContext::getAssociativeCOFFSection(const MCSectionCOFF *Sec,
396 const MCSymbol *KeySym) {
397 // Return the normal section if we don't have to be associative.
401 // Make an associative section with the same name and kind as the normal
403 unsigned Characteristics =
404 Sec->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT;
405 return getCOFFSection(Sec->getSectionName(), Characteristics, Sec->getKind(),
407 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE);
410 //===----------------------------------------------------------------------===//
412 //===----------------------------------------------------------------------===//
414 /// GetDwarfFile - takes a file name an number to place in the dwarf file and
415 /// directory tables. If the file number has already been allocated it is an
416 /// error and zero is returned and the client reports the error, else the
417 /// allocated file number is returned. The file numbers may be in any order.
418 unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
419 unsigned FileNumber, unsigned CUID) {
420 MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
421 return Table.getFile(Directory, FileName, FileNumber);
424 /// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
425 /// currently is assigned and false otherwise.
426 bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
427 const SmallVectorImpl<MCDwarfFile>& MCDwarfFiles = getMCDwarfFiles(CUID);
428 if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
431 return !MCDwarfFiles[FileNumber].Name.empty();
434 /// finalizeDwarfSections - Emit end symbols for each non-empty code section.
435 /// Also remove empty sections from SectionStartEndSyms, to avoid generating
436 /// useless debug info for them.
437 void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
438 MCContext &context = MCOS.getContext();
440 auto sec = SectionStartEndSyms.begin();
441 while (sec != SectionStartEndSyms.end()) {
442 assert(sec->second.first && "Start symbol must be set by now");
443 MCOS.SwitchSection(sec->first);
444 if (MCOS.mayHaveInstructions()) {
445 MCSymbol *SectionEndSym = context.CreateTempSymbol();
446 MCOS.EmitLabel(SectionEndSym);
447 sec->second.second = SectionEndSym;
450 MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
452 sec = SectionStartEndSyms.erase(to_erase);
457 void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
458 // If we have a source manager and a location, use it. Otherwise just
459 // use the generic report_fatal_error().
460 if (!SrcMgr || Loc == SMLoc())
461 report_fatal_error(Msg, false);
463 // Use the source manager to print the message.
464 SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
466 // If we reached here, we are failing ungracefully. Run the interrupt handlers
467 // to make sure any special cleanups get done, in particular that we remove
468 // files registered with RemoveFileOnSignal.
469 sys::RunInterruptHandlers();