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 SectionsForRanges.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::getOrCreateLSDASymbol(StringRef FuncName) {
148 return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + "__ehtable$" +
152 MCSymbol *MCContext::CreateSymbol(StringRef Name, bool AlwaysAddSuffix) {
153 // Determine whether this is an assembler temporary or normal label, if used.
154 bool IsTemporary = false;
155 if (AllowTemporaryLabels)
156 IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
158 if (IsTemporary && AlwaysAddSuffix && !UseNamesOnTempLabels)
159 return new (*this) MCSymbol("", true);
161 SmallString<128> NewName = Name;
162 bool AddSuffix = AlwaysAddSuffix;
163 unsigned &NextUniqueID = NextID[Name];
166 NewName.resize(Name.size());
167 raw_svector_ostream(NewName) << NextUniqueID++;
169 auto NameEntry = UsedNames.insert(std::make_pair(NewName, true));
170 if (NameEntry.second) {
171 // Ok, we found a name. Have the MCSymbol object itself refer to the copy
172 // of the string that is embedded in the UsedNames entry.
174 new (*this) MCSymbol(NameEntry.first->getKey(), IsTemporary);
177 assert(IsTemporary && "Cannot rename non-temporary symbols");
180 llvm_unreachable("Infinite loop");
183 MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix) {
184 SmallString<128> NameSV;
185 raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
186 return CreateSymbol(NameSV, AlwaysAddSuffix);
189 MCSymbol *MCContext::createLinkerPrivateTempSymbol() {
190 SmallString<128> NameSV;
191 raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << "tmp";
192 return CreateSymbol(NameSV, true);
195 MCSymbol *MCContext::createTempSymbol() {
196 return createTempSymbol("tmp", true);
199 unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
200 MCLabel *&Label = Instances[LocalLabelVal];
202 Label = new (*this) MCLabel(0);
203 return Label->incInstance();
206 unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
207 MCLabel *&Label = Instances[LocalLabelVal];
209 Label = new (*this) MCLabel(0);
210 return Label->getInstance();
213 MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
215 MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
217 Sym = createTempSymbol();
221 MCSymbol *MCContext::createDirectionalLocalSymbol(unsigned LocalLabelVal) {
222 unsigned Instance = NextInstance(LocalLabelVal);
223 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
226 MCSymbol *MCContext::getDirectionalLocalSymbol(unsigned LocalLabelVal,
228 unsigned Instance = GetInstance(LocalLabelVal);
231 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
234 MCSymbol *MCContext::lookupSymbol(const Twine &Name) const {
235 SmallString<128> NameSV;
236 StringRef NameRef = Name.toStringRef(NameSV);
237 return Symbols.lookup(NameRef);
240 //===----------------------------------------------------------------------===//
241 // Section Management
242 //===----------------------------------------------------------------------===//
244 const MCSectionMachO *
245 MCContext::getMachOSection(StringRef Segment, StringRef Section,
246 unsigned TypeAndAttributes, unsigned Reserved2,
247 SectionKind Kind, const char *BeginSymName) {
249 // We unique sections by their segment/section pair. The returned section
250 // may not have the same flags as the requested section, if so this should be
251 // diagnosed by the client as an error.
253 // Form the name to look up.
254 SmallString<64> Name;
259 // Do the lookup, if we have a hit, return it.
260 const MCSectionMachO *&Entry = MachOUniquingMap[Name];
264 MCSymbol *Begin = nullptr;
266 Begin = createTempSymbol(BeginSymName, false);
268 // Otherwise, return a new section.
269 return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
270 Reserved2, Kind, Begin);
273 void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
275 if (const MCSymbol *Group = Section->getGroup())
276 GroupName = Group->getName();
278 unsigned UniqueID = Section->getUniqueID();
279 ELFUniquingMap.erase(
280 ELFSectionKey{Section->getSectionName(), GroupName, UniqueID});
281 auto I = ELFUniquingMap.insert(std::make_pair(
282 ELFSectionKey{Name, GroupName, UniqueID},
285 StringRef CachedName = I->first.SectionName;
286 const_cast<MCSectionELF *>(Section)->setSectionName(CachedName);
290 MCContext::createELFRelSection(StringRef Name, unsigned Type, unsigned Flags,
291 unsigned EntrySize, const MCSymbol *Group,
292 const MCSectionELF *Associated) {
293 StringMap<bool>::iterator I;
295 std::tie(I, Inserted) = ELFRelSecNames.insert(std::make_pair(Name, true));
298 MCSectionELF(I->getKey(), Type, Flags, SectionKind::getReadOnly(),
299 EntrySize, Group, true, nullptr, Associated);
302 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
303 unsigned Flags, unsigned EntrySize,
304 StringRef Group, unsigned UniqueID,
305 const char *BeginSymName) {
306 MCSymbol *GroupSym = nullptr;
308 GroupSym = getOrCreateSymbol(Group);
310 return getELFSection(Section, Type, Flags, EntrySize, GroupSym, UniqueID,
311 BeginSymName, nullptr);
314 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
315 unsigned Flags, unsigned EntrySize,
316 const MCSymbol *GroupSym,
318 const char *BeginSymName,
319 const MCSectionELF *Associated) {
320 StringRef Group = "";
322 Group = GroupSym->getName();
323 // Do the lookup, if we have a hit, return it.
324 auto IterBool = ELFUniquingMap.insert(
325 std::make_pair(ELFSectionKey{Section, Group, UniqueID}, nullptr));
326 auto &Entry = *IterBool.first;
327 if (!IterBool.second)
330 StringRef CachedName = Entry.first.SectionName;
333 if (Flags & ELF::SHF_EXECINSTR)
334 Kind = SectionKind::getText();
336 Kind = SectionKind::getReadOnly();
338 MCSymbol *Begin = nullptr;
340 Begin = createTempSymbol(BeginSymName, false);
342 MCSectionELF *Result =
343 new (*this) MCSectionELF(CachedName, Type, Flags, Kind, EntrySize,
344 GroupSym, UniqueID, Begin, Associated);
345 Entry.second = Result;
349 const MCSectionELF *MCContext::createELFGroupSection(const MCSymbol *Group) {
350 MCSectionELF *Result = new (*this)
351 MCSectionELF(".group", ELF::SHT_GROUP, 0, SectionKind::getReadOnly(), 4,
352 Group, ~0, nullptr, nullptr);
356 const MCSectionCOFF *
357 MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
358 SectionKind Kind, StringRef COMDATSymName,
359 int Selection, const char *BeginSymName) {
360 MCSymbol *COMDATSymbol = nullptr;
361 if (!COMDATSymName.empty()) {
362 COMDATSymbol = getOrCreateSymbol(COMDATSymName);
363 COMDATSymName = COMDATSymbol->getName();
366 // Do the lookup, if we have a hit, return it.
367 COFFSectionKey T{Section, COMDATSymName, Selection};
368 auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
369 auto Iter = IterBool.first;
370 if (!IterBool.second)
373 MCSymbol *Begin = nullptr;
375 Begin = createTempSymbol(BeginSymName, false);
377 StringRef CachedName = Iter->first.SectionName;
378 MCSectionCOFF *Result = new (*this) MCSectionCOFF(
379 CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);
381 Iter->second = Result;
385 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
386 unsigned Characteristics,
388 const char *BeginSymName) {
389 return getCOFFSection(Section, Characteristics, Kind, "", 0, BeginSymName);
392 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
393 COFFSectionKey T{Section, "", 0};
394 auto Iter = COFFUniquingMap.find(T);
395 if (Iter == COFFUniquingMap.end())
400 const MCSectionCOFF *
401 MCContext::getAssociativeCOFFSection(const MCSectionCOFF *Sec,
402 const MCSymbol *KeySym) {
403 // Return the normal section if we don't have to be associative.
407 // Make an associative section with the same name and kind as the normal
409 unsigned Characteristics =
410 Sec->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT;
411 return getCOFFSection(Sec->getSectionName(), Characteristics, Sec->getKind(),
413 COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE);
416 //===----------------------------------------------------------------------===//
418 //===----------------------------------------------------------------------===//
420 /// getDwarfFile - takes a file name an number to place in the dwarf file and
421 /// directory tables. If the file number has already been allocated it is an
422 /// error and zero is returned and the client reports the error, else the
423 /// allocated file number is returned. The file numbers may be in any order.
424 unsigned MCContext::getDwarfFile(StringRef Directory, StringRef FileName,
425 unsigned FileNumber, unsigned CUID) {
426 MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
427 return Table.getFile(Directory, FileName, FileNumber);
430 /// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
431 /// currently is assigned and false otherwise.
432 bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
433 const SmallVectorImpl<MCDwarfFile> &MCDwarfFiles = getMCDwarfFiles(CUID);
434 if (FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
437 return !MCDwarfFiles[FileNumber].Name.empty();
440 /// Remove empty sections from SectionStartEndSyms, to avoid generating
441 /// useless debug info for them.
442 void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
443 std::vector<const MCSection *> Keep;
444 for (const MCSection *Sec : SectionsForRanges) {
445 if (MCOS.mayHaveInstructions(*Sec))
448 SectionsForRanges.clear();
449 SectionsForRanges.insert(Keep.begin(), Keep.end());
452 void MCContext::reportFatalError(SMLoc Loc, const Twine &Msg) const {
453 // If we have a source manager and a location, use it. Otherwise just
454 // use the generic report_fatal_error().
455 if (!SrcMgr || Loc == SMLoc())
456 report_fatal_error(Msg, false);
458 // Use the source manager to print the message.
459 SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
461 // If we reached here, we are failing ungracefully. Run the interrupt handlers
462 // to make sure any special cleanups get done, in particular that we remove
463 // files registered with RemoveFileOnSignal.
464 sys::RunInterruptHandlers();