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/MCSymbol.h"
22 #include "llvm/Support/ELF.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/FileSystem.h"
25 #include "llvm/Support/MemoryBuffer.h"
26 #include "llvm/Support/Signals.h"
27 #include "llvm/Support/SourceMgr.h"
32 MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
33 const MCObjectFileInfo *mofi, const SourceMgr *mgr,
35 : SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi), Allocator(),
36 Symbols(Allocator), UsedNames(Allocator), NextUniqueID(0),
37 CurrentDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0), DwarfLocSeen(false),
38 GenDwarfForAssembly(false), GenDwarfFileNumber(0), DwarfVersion(4),
39 AllowTemporaryLabels(true), DwarfCompileUnitID(0),
40 AutoReset(DoAutoReset) {
42 std::error_code EC = llvm::sys::fs::current_path(CompilationDir);
44 CompilationDir.clear();
46 SecureLogFile = getenv("AS_SECURE_LOG_FILE");
48 SecureLogUsed = false;
50 if (SrcMgr && SrcMgr->getNumBuffers() > 0)
51 MainFileName = SrcMgr->getMemoryBuffer(0)->getBufferIdentifier();
54 MCContext::~MCContext() {
59 // NOTE: The symbols are all allocated out of a bump pointer allocator,
60 // we don't need to free them here.
62 // If the stream for the .secure_log_unique directive was created free it.
63 delete (raw_ostream*)SecureLog;
66 //===----------------------------------------------------------------------===//
67 // Module Lifetime Management
68 //===----------------------------------------------------------------------===//
70 void MCContext::reset() {
75 MCDwarfLineTablesCUMap.clear();
76 MCGenDwarfLabelEntries.clear();
77 DwarfDebugFlags = StringRef();
78 DwarfCompileUnitID = 0;
79 CurrentDwarfLoc = MCDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0);
81 MachOUniquingMap.clear();
82 ELFUniquingMap.clear();
83 COFFUniquingMap.clear();
86 AllowTemporaryLabels = true;
88 GenDwarfForAssembly = false;
89 GenDwarfFileNumber = 0;
92 //===----------------------------------------------------------------------===//
93 // Symbol Manipulation
94 //===----------------------------------------------------------------------===//
96 MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
97 assert(!Name.empty() && "Normal symbols cannot be unnamed!");
99 // Do the lookup and get the entire StringMapEntry. We want access to the
100 // key if we are creating the entry.
101 StringMapEntry<MCSymbol*> &Entry = Symbols.GetOrCreateValue(Name);
102 MCSymbol *Sym = Entry.getValue();
107 Sym = CreateSymbol(Name);
112 MCSymbol *MCContext::CreateSymbol(StringRef Name) {
113 // Determine whether this is an assembler temporary or normal label, if used.
114 bool isTemporary = false;
115 if (AllowTemporaryLabels)
116 isTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
118 StringMapEntry<bool> *NameEntry = &UsedNames.GetOrCreateValue(Name);
119 if (NameEntry->getValue()) {
120 assert(isTemporary && "Cannot rename non-temporary symbols");
121 SmallString<128> NewName = Name;
123 NewName.resize(Name.size());
124 raw_svector_ostream(NewName) << NextUniqueID++;
125 NameEntry = &UsedNames.GetOrCreateValue(NewName);
126 } while (NameEntry->getValue());
128 NameEntry->setValue(true);
130 // Ok, the entry doesn't already exist. Have the MCSymbol object itself refer
131 // to the copy of the string that is embedded in the UsedNames entry.
132 MCSymbol *Result = new (*this) MCSymbol(NameEntry->getKey(), isTemporary);
137 MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
138 SmallString<128> NameSV;
139 return GetOrCreateSymbol(Name.toStringRef(NameSV));
142 MCSymbol *MCContext::CreateLinkerPrivateTempSymbol() {
143 small_string_ostream<128> NameSV;
144 NameSV << MAI->getLinkerPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
145 return CreateSymbol(NameSV.str());
148 MCSymbol *MCContext::CreateTempSymbol() {
149 small_string_ostream<128> NameSV;
150 NameSV << MAI->getPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
151 return CreateSymbol(NameSV.str());
154 unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
155 MCLabel *&Label = Instances[LocalLabelVal];
157 Label = new (*this) MCLabel(0);
158 return Label->incInstance();
161 unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
162 MCLabel *&Label = Instances[LocalLabelVal];
164 Label = new (*this) MCLabel(0);
165 return Label->getInstance();
168 MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
170 MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
172 Sym = CreateTempSymbol();
176 MCSymbol *MCContext::CreateDirectionalLocalSymbol(unsigned LocalLabelVal) {
177 unsigned Instance = NextInstance(LocalLabelVal);
178 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
181 MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
183 unsigned Instance = GetInstance(LocalLabelVal);
186 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
189 MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
190 return Symbols.lookup(Name);
193 MCSymbol *MCContext::LookupSymbol(const Twine &Name) const {
194 SmallString<128> NameSV;
195 Name.toVector(NameSV);
196 return LookupSymbol(NameSV.str());
199 //===----------------------------------------------------------------------===//
200 // Section Management
201 //===----------------------------------------------------------------------===//
203 const MCSectionMachO *MCContext::
204 getMachOSection(StringRef Segment, StringRef Section,
205 unsigned TypeAndAttributes,
206 unsigned Reserved2, SectionKind Kind) {
208 // We unique sections by their segment/section pair. The returned section
209 // may not have the same flags as the requested section, if so this should be
210 // diagnosed by the client as an error.
212 // Form the name to look up.
213 SmallString<64> Name;
218 // Do the lookup, if we have a hit, return it.
219 const MCSectionMachO *&Entry = MachOUniquingMap[Name.str()];
220 if (Entry) return Entry;
222 // Otherwise, return a new section.
223 return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
227 const MCSectionELF *MCContext::
228 getELFSection(StringRef Section, unsigned Type, unsigned Flags,
230 return getELFSection(Section, Type, Flags, Kind, 0, "");
233 void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
235 if (const MCSymbol *Group = Section->getGroup())
236 GroupName = Group->getName();
238 ELFUniquingMap.erase(SectionGroupPair(Section->getSectionName(), GroupName));
240 ELFUniquingMap.insert(std::make_pair(SectionGroupPair(Name, GroupName),
242 StringRef CachedName = I->first.first;
243 const_cast<MCSectionELF*>(Section)->setSectionName(CachedName);
246 const MCSectionELF *MCContext::
247 getELFSection(StringRef Section, unsigned Type, unsigned Flags,
248 SectionKind Kind, unsigned EntrySize, StringRef Group) {
249 // Do the lookup, if we have a hit, return it.
250 auto IterBool = ELFUniquingMap.insert(
251 std::make_pair(SectionGroupPair(Section, Group), nullptr));
252 auto &Entry = *IterBool.first;
253 if (!IterBool.second) return Entry.second;
255 // Possibly refine the entry size first.
257 EntrySize = MCSectionELF::DetermineEntrySize(Kind);
260 MCSymbol *GroupSym = nullptr;
262 GroupSym = GetOrCreateSymbol(Group);
264 StringRef CachedName = Entry.first.first;
265 MCSectionELF *Result = new (*this)
266 MCSectionELF(CachedName, Type, Flags, Kind, EntrySize, GroupSym);
267 Entry.second = Result;
271 const MCSectionELF *MCContext::CreateELFGroupSection() {
272 MCSectionELF *Result =
273 new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
274 SectionKind::getReadOnly(), 4, nullptr);
278 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
279 unsigned Characteristics,
281 StringRef COMDATSymName,
283 // Do the lookup, if we have a hit, return it.
285 SectionGroupPair P(Section, COMDATSymName);
286 auto IterBool = COFFUniquingMap.insert(std::make_pair(P, nullptr));
287 auto Iter = IterBool.first;
288 if (!IterBool.second)
291 const MCSymbol *COMDATSymbol = nullptr;
292 if (!COMDATSymName.empty())
293 COMDATSymbol = GetOrCreateSymbol(COMDATSymName);
295 StringRef CachedName = Iter->first.first;
296 MCSectionCOFF *Result = new (*this)
297 MCSectionCOFF(CachedName, Characteristics, COMDATSymbol, Selection, Kind);
299 Iter->second = Result;
303 const MCSectionCOFF *
304 MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
306 return getCOFFSection(Section, Characteristics, Kind, "", 0);
309 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
310 SectionGroupPair P(Section, "");
311 auto Iter = COFFUniquingMap.find(P);
312 if (Iter == COFFUniquingMap.end())
317 //===----------------------------------------------------------------------===//
319 //===----------------------------------------------------------------------===//
321 /// GetDwarfFile - takes a file name an number to place in the dwarf file and
322 /// directory tables. If the file number has already been allocated it is an
323 /// error and zero is returned and the client reports the error, else the
324 /// allocated file number is returned. The file numbers may be in any order.
325 unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
326 unsigned FileNumber, unsigned CUID) {
327 MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
328 return Table.getFile(Directory, FileName, FileNumber);
331 /// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
332 /// currently is assigned and false otherwise.
333 bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
334 const SmallVectorImpl<MCDwarfFile>& MCDwarfFiles = getMCDwarfFiles(CUID);
335 if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
338 return !MCDwarfFiles[FileNumber].Name.empty();
341 /// finalizeDwarfSections - Emit end symbols for each non-empty code section.
342 /// Also remove empty sections from SectionStartEndSyms, to avoid generating
343 /// useless debug info for them.
344 void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
345 MCContext &context = MCOS.getContext();
347 auto sec = SectionStartEndSyms.begin();
348 while (sec != SectionStartEndSyms.end()) {
349 assert(sec->second.first && "Start symbol must be set by now");
350 MCOS.SwitchSection(sec->first);
351 if (MCOS.mayHaveInstructions()) {
352 MCSymbol *SectionEndSym = context.CreateTempSymbol();
353 MCOS.EmitLabel(SectionEndSym);
354 sec->second.second = SectionEndSym;
357 MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
359 sec = SectionStartEndSyms.erase(to_erase);
364 void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
365 // If we have a source manager and a location, use it. Otherwise just
366 // use the generic report_fatal_error().
367 if (!SrcMgr || Loc == SMLoc())
368 report_fatal_error(Msg, false);
370 // Use the source manager to print the message.
371 SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
373 // If we reached here, we are failing ungracefully. Run the interrupt handlers
374 // to make sure any special cleanups get done, in particular that we remove
375 // files registered with RemoveFileOnSignal.
376 sys::RunInterruptHandlers();