1//===- lib/MC/MCContext.cpp - Machine Code Context ------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
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/MemoryBuffer.h"
25#include "llvm/Support/Signals.h"
26#include "llvm/Support/SourceMgr.h"
27using namespace llvm;
28
29typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
30typedef StringMap<const MCSectionELF*> ELFUniqueMapTy;
31typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy;
32
33
34MCContext::MCContext(const MCAsmInfo &mai, const MCRegisterInfo &mri,
35                     const MCObjectFileInfo *mofi, const SourceMgr *mgr,
36                     bool DoAutoReset) :
37  SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi),
38  Allocator(), Symbols(Allocator), UsedNames(Allocator),
39  NextUniqueID(0),
40  CompilationDir(llvm::sys::Path::GetCurrentDirectory().str()),
41  CurrentDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0),
42  DwarfLocSeen(false), GenDwarfForAssembly(false), GenDwarfFileNumber(0),
43  AllowTemporaryLabels(true), DwarfCompileUnitID(0), AutoReset(DoAutoReset) {
44
45  MachOUniquingMap = 0;
46  ELFUniquingMap = 0;
47  COFFUniquingMap = 0;
48
49  SecureLogFile = getenv("AS_SECURE_LOG_FILE");
50  SecureLog = 0;
51  SecureLogUsed = false;
52
53  if (SrcMgr && SrcMgr->getNumBuffers() > 0)
54    MainFileName = SrcMgr->getMemoryBuffer(0)->getBufferIdentifier();
55  else
56    MainFileName = "";
57}
58
59MCContext::~MCContext() {
60
61  if (AutoReset)
62    reset();
63
64  // NOTE: The symbols are all allocated out of a bump pointer allocator,
65  // we don't need to free them here.
66
67  // If the stream for the .secure_log_unique directive was created free it.
68  delete (raw_ostream*)SecureLog;
69}
70
71//===----------------------------------------------------------------------===//
72// Module Lifetime Management
73//===----------------------------------------------------------------------===//
74
75void MCContext::reset() {
76  UsedNames.clear();
77  Symbols.clear();
78  Allocator.Reset();
79  Instances.clear();
80  MCDwarfFilesCUMap.clear();
81  MCDwarfDirsCUMap.clear();
82  MCGenDwarfLabelEntries.clear();
83  DwarfDebugFlags = StringRef();
84  MCLineSections.clear();
85  MCLineSectionOrder.clear();
86  DwarfCompileUnitID = 0;
87  MCLineTableSymbols.clear();
88  CurrentDwarfLoc = MCDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0);
89
90  // If we have the MachO uniquing map, free it.
91  delete (MachOUniqueMapTy*)MachOUniquingMap;
92  delete (ELFUniqueMapTy*)ELFUniquingMap;
93  delete (COFFUniqueMapTy*)COFFUniquingMap;
94  MachOUniquingMap = 0;
95  ELFUniquingMap = 0;
96  COFFUniquingMap = 0;
97
98  NextUniqueID = 0;
99  AllowTemporaryLabels = true;
100  DwarfLocSeen = false;
101  GenDwarfForAssembly = false;
102  GenDwarfFileNumber = 0;
103}
104
105//===----------------------------------------------------------------------===//
106// Symbol Manipulation
107//===----------------------------------------------------------------------===//
108
109MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
110  assert(!Name.empty() && "Normal symbols cannot be unnamed!");
111
112  // Do the lookup and get the entire StringMapEntry.  We want access to the
113  // key if we are creating the entry.
114  StringMapEntry<MCSymbol*> &Entry = Symbols.GetOrCreateValue(Name);
115  MCSymbol *Sym = Entry.getValue();
116
117  if (Sym)
118    return Sym;
119
120  Sym = CreateSymbol(Name);
121  Entry.setValue(Sym);
122  return Sym;
123}
124
125MCSymbol *MCContext::CreateSymbol(StringRef Name) {
126  // Determine whether this is an assembler temporary or normal label, if used.
127  bool isTemporary = false;
128  if (AllowTemporaryLabels)
129    isTemporary = Name.startswith(MAI.getPrivateGlobalPrefix());
130
131  StringMapEntry<bool> *NameEntry = &UsedNames.GetOrCreateValue(Name);
132  if (NameEntry->getValue()) {
133    assert(isTemporary && "Cannot rename non temporary symbols");
134    SmallString<128> NewName = Name;
135    do {
136      NewName.resize(Name.size());
137      raw_svector_ostream(NewName) << NextUniqueID++;
138      NameEntry = &UsedNames.GetOrCreateValue(NewName);
139    } while (NameEntry->getValue());
140  }
141  NameEntry->setValue(true);
142
143  // Ok, the entry doesn't already exist.  Have the MCSymbol object itself refer
144  // to the copy of the string that is embedded in the UsedNames entry.
145  MCSymbol *Result = new (*this) MCSymbol(NameEntry->getKey(), isTemporary);
146
147  return Result;
148}
149
150MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
151  SmallString<128> NameSV;
152  Name.toVector(NameSV);
153  return GetOrCreateSymbol(NameSV.str());
154}
155
156MCSymbol *MCContext::CreateTempSymbol() {
157  SmallString<128> NameSV;
158  raw_svector_ostream(NameSV)
159    << MAI.getPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
160  return CreateSymbol(NameSV);
161}
162
163unsigned MCContext::NextInstance(int64_t LocalLabelVal) {
164  MCLabel *&Label = Instances[LocalLabelVal];
165  if (!Label)
166    Label = new (*this) MCLabel(0);
167  return Label->incInstance();
168}
169
170unsigned MCContext::GetInstance(int64_t LocalLabelVal) {
171  MCLabel *&Label = Instances[LocalLabelVal];
172  if (!Label)
173    Label = new (*this) MCLabel(0);
174  return Label->getInstance();
175}
176
177MCSymbol *MCContext::CreateDirectionalLocalSymbol(int64_t LocalLabelVal) {
178  return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
179                           Twine(LocalLabelVal) +
180                           "\2" +
181                           Twine(NextInstance(LocalLabelVal)));
182}
183MCSymbol *MCContext::GetDirectionalLocalSymbol(int64_t LocalLabelVal,
184                                               int bORf) {
185  return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
186                           Twine(LocalLabelVal) +
187                           "\2" +
188                           Twine(GetInstance(LocalLabelVal) + bORf));
189}
190
191MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
192  return Symbols.lookup(Name);
193}
194
195MCSymbol *MCContext::LookupSymbol(const Twine &Name) const {
196  SmallString<128> NameSV;
197  Name.toVector(NameSV);
198  return LookupSymbol(NameSV.str());
199}
200
201//===----------------------------------------------------------------------===//
202// Section Management
203//===----------------------------------------------------------------------===//
204
205const MCSectionMachO *MCContext::
206getMachOSection(StringRef Segment, StringRef Section,
207                unsigned TypeAndAttributes,
208                unsigned Reserved2, SectionKind Kind) {
209
210  // We unique sections by their segment/section pair.  The returned section
211  // may not have the same flags as the requested section, if so this should be
212  // diagnosed by the client as an error.
213
214  // Create the map if it doesn't already exist.
215  if (MachOUniquingMap == 0)
216    MachOUniquingMap = new MachOUniqueMapTy();
217  MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)MachOUniquingMap;
218
219  // Form the name to look up.
220  SmallString<64> Name;
221  Name += Segment;
222  Name.push_back(',');
223  Name += Section;
224
225  // Do the lookup, if we have a hit, return it.
226  const MCSectionMachO *&Entry = Map[Name.str()];
227  if (Entry) return Entry;
228
229  // Otherwise, return a new section.
230  return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
231                                            Reserved2, Kind);
232}
233
234const MCSectionELF *MCContext::
235getELFSection(StringRef Section, unsigned Type, unsigned Flags,
236              SectionKind Kind) {
237  return getELFSection(Section, Type, Flags, Kind, 0, "");
238}
239
240const MCSectionELF *MCContext::
241getELFSection(StringRef Section, unsigned Type, unsigned Flags,
242              SectionKind Kind, unsigned EntrySize, StringRef Group) {
243  if (ELFUniquingMap == 0)
244    ELFUniquingMap = new ELFUniqueMapTy();
245  ELFUniqueMapTy &Map = *(ELFUniqueMapTy*)ELFUniquingMap;
246
247  // Do the lookup, if we have a hit, return it.
248  StringMapEntry<const MCSectionELF*> &Entry = Map.GetOrCreateValue(Section);
249  if (Entry.getValue()) return Entry.getValue();
250
251  // Possibly refine the entry size first.
252  if (!EntrySize) {
253    EntrySize = MCSectionELF::DetermineEntrySize(Kind);
254  }
255
256  MCSymbol *GroupSym = NULL;
257  if (!Group.empty())
258    GroupSym = GetOrCreateSymbol(Group);
259
260  MCSectionELF *Result = new (*this) MCSectionELF(Entry.getKey(), Type, Flags,
261                                                  Kind, EntrySize, GroupSym);
262  Entry.setValue(Result);
263  return Result;
264}
265
266const MCSectionELF *MCContext::CreateELFGroupSection() {
267  MCSectionELF *Result =
268    new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
269                             SectionKind::getReadOnly(), 4, NULL);
270  return Result;
271}
272
273const MCSection *MCContext::getCOFFSection(StringRef Section,
274                                           unsigned Characteristics,
275                                           int Selection,
276                                           SectionKind Kind) {
277  if (COFFUniquingMap == 0)
278    COFFUniquingMap = new COFFUniqueMapTy();
279  COFFUniqueMapTy &Map = *(COFFUniqueMapTy*)COFFUniquingMap;
280
281  // Do the lookup, if we have a hit, return it.
282  StringMapEntry<const MCSectionCOFF*> &Entry = Map.GetOrCreateValue(Section);
283  if (Entry.getValue()) return Entry.getValue();
284
285  MCSectionCOFF *Result = new (*this) MCSectionCOFF(Entry.getKey(),
286                                                    Characteristics,
287                                                    Selection, Kind);
288
289  Entry.setValue(Result);
290  return Result;
291}
292
293//===----------------------------------------------------------------------===//
294// Dwarf Management
295//===----------------------------------------------------------------------===//
296
297/// GetDwarfFile - takes a file name an number to place in the dwarf file and
298/// directory tables.  If the file number has already been allocated it is an
299/// error and zero is returned and the client reports the error, else the
300/// allocated file number is returned.  The file numbers may be in any order.
301unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
302                                 unsigned FileNumber, unsigned CUID) {
303  // TODO: a FileNumber of zero says to use the next available file number.
304  // Note: in GenericAsmParser::ParseDirectiveFile() FileNumber was checked
305  // to not be less than one.  This needs to be change to be not less than zero.
306
307  SmallVectorImpl<MCDwarfFile *>& MCDwarfFiles = MCDwarfFilesCUMap[CUID];
308  SmallVectorImpl<StringRef>& MCDwarfDirs = MCDwarfDirsCUMap[CUID];
309  // Make space for this FileNumber in the MCDwarfFiles vector if needed.
310  if (FileNumber >= MCDwarfFiles.size()) {
311    MCDwarfFiles.resize(FileNumber + 1);
312  } else {
313    MCDwarfFile *&ExistingFile = MCDwarfFiles[FileNumber];
314    if (ExistingFile)
315      // It is an error to use see the same number more than once.
316      return 0;
317  }
318
319  // Get the new MCDwarfFile slot for this FileNumber.
320  MCDwarfFile *&File = MCDwarfFiles[FileNumber];
321
322  if (Directory.empty()) {
323    // Separate the directory part from the basename of the FileName.
324    StringRef tFileName = sys::path::filename(FileName);
325    if (!tFileName.empty()) {
326      Directory = sys::path::parent_path(FileName);
327      if (!Directory.empty())
328        FileName = tFileName;
329    }
330  }
331
332  // Find or make a entry in the MCDwarfDirs vector for this Directory.
333  // Capture directory name.
334  unsigned DirIndex;
335  if (Directory.empty()) {
336    // For FileNames with no directories a DirIndex of 0 is used.
337    DirIndex = 0;
338  } else {
339    DirIndex = 0;
340    for (unsigned End = MCDwarfDirs.size(); DirIndex < End; DirIndex++) {
341      if (Directory == MCDwarfDirs[DirIndex])
342        break;
343    }
344    if (DirIndex >= MCDwarfDirs.size()) {
345      char *Buf = static_cast<char *>(Allocate(Directory.size()));
346      memcpy(Buf, Directory.data(), Directory.size());
347      MCDwarfDirs.push_back(StringRef(Buf, Directory.size()));
348    }
349    // The DirIndex is one based, as DirIndex of 0 is used for FileNames with
350    // no directories.  MCDwarfDirs[] is unlike MCDwarfFiles[] in that the
351    // directory names are stored at MCDwarfDirs[DirIndex-1] where FileNames
352    // are stored at MCDwarfFiles[FileNumber].Name .
353    DirIndex++;
354  }
355
356  // Now make the MCDwarfFile entry and place it in the slot in the MCDwarfFiles
357  // vector.
358  char *Buf = static_cast<char *>(Allocate(FileName.size()));
359  memcpy(Buf, FileName.data(), FileName.size());
360  File = new (*this) MCDwarfFile(StringRef(Buf, FileName.size()), DirIndex);
361
362  // return the allocated FileNumber.
363  return FileNumber;
364}
365
366/// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
367/// currently is assigned and false otherwise.
368bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
369  SmallVectorImpl<MCDwarfFile *>& MCDwarfFiles = MCDwarfFilesCUMap[CUID];
370  if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
371    return false;
372
373  return MCDwarfFiles[FileNumber] != 0;
374}
375
376void MCContext::FatalError(SMLoc Loc, const Twine &Msg) {
377  // If we have a source manager and a location, use it. Otherwise just
378  // use the generic report_fatal_error().
379  if (!SrcMgr || Loc == SMLoc())
380    report_fatal_error(Msg);
381
382  // Use the source manager to print the message.
383  SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
384
385  // If we reached here, we are failing ungracefully. Run the interrupt handlers
386  // to make sure any special cleanups get done, in particular that we remove
387  // files registered with RemoveFileOnSignal.
388  sys::RunInterruptHandlers();
389  exit(1);
390}
391