MCContext.h revision 613b7576896fbd03fe495f4ee27b404f81386774
1//===- MCContext.h - Machine Code Context -----------------------*- C++ -*-===//
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#ifndef LLVM_MC_MCCONTEXT_H
11#define LLVM_MC_MCCONTEXT_H
12
13#include "llvm/MC/SectionKind.h"
14#include "llvm/MC/MCDwarf.h"
15#include "llvm/ADT/DenseMap.h"
16#include "llvm/ADT/StringMap.h"
17#include "llvm/Support/Allocator.h"
18#include "llvm/Support/raw_ostream.h"
19#include <vector> // FIXME: Shouldn't be needed.
20
21namespace llvm {
22  class MCAsmInfo;
23  class MCExpr;
24  class MCSection;
25  class MCSymbol;
26  class MCLabel;
27  class MCDwarfFile;
28  class MCDwarfLoc;
29  class MCObjectFileInfo;
30  class MCRegisterInfo;
31  class MCLineSection;
32  class StringRef;
33  class Twine;
34  class MCSectionMachO;
35  class MCSectionELF;
36
37  /// MCContext - Context object for machine code objects.  This class owns all
38  /// of the sections that it creates.
39  ///
40  class MCContext {
41    MCContext(const MCContext&); // DO NOT IMPLEMENT
42    MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
43  public:
44    typedef StringMap<MCSymbol*, BumpPtrAllocator&> SymbolTable;
45  private:
46
47    /// The MCAsmInfo for this target.
48    const MCAsmInfo &MAI;
49
50    /// The MCRegisterInfo for this target.
51    const MCRegisterInfo &MRI;
52
53    /// The MCObjectFileInfo for this target.
54    const MCObjectFileInfo *MOFI;
55
56    /// Allocator - Allocator object used for creating machine code objects.
57    ///
58    /// We use a bump pointer allocator to avoid the need to track all allocated
59    /// objects.
60    BumpPtrAllocator Allocator;
61
62    /// Symbols - Bindings of names to symbols.
63    SymbolTable Symbols;
64
65    /// UsedNames - Keeps tracks of names that were used both for used declared
66    /// and artificial symbols.
67    StringMap<bool, BumpPtrAllocator&> UsedNames;
68
69    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
70    /// symbol.
71    unsigned NextUniqueID;
72
73    /// Instances of directional local labels.
74    DenseMap<unsigned, MCLabel *> Instances;
75    /// NextInstance() creates the next instance of the directional local label
76    /// for the LocalLabelVal and adds it to the map if needed.
77    unsigned NextInstance(int64_t LocalLabelVal);
78    /// GetInstance() gets the current instance of the directional local label
79    /// for the LocalLabelVal and adds it to the map if needed.
80    unsigned GetInstance(int64_t LocalLabelVal);
81
82    /// The file name of the log file from the environment variable
83    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
84    /// directive is used or it is an error.
85    char *SecureLogFile;
86    /// The stream that gets written to for the .secure_log_unique directive.
87    raw_ostream *SecureLog;
88    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
89    /// catch errors if .secure_log_unique appears twice without
90    /// .secure_log_reset appearing between them.
91    bool SecureLogUsed;
92
93    /// The dwarf file and directory tables from the dwarf .file directive.
94    std::vector<MCDwarfFile *> MCDwarfFiles;
95    std::vector<StringRef> MCDwarfDirs;
96
97    /// The current dwarf line information from the last dwarf .loc directive.
98    MCDwarfLoc CurrentDwarfLoc;
99    bool DwarfLocSeen;
100
101    /// Generate dwarf debugging info for assembly source files.
102    bool GenDwarfForAssembly;
103
104    /// The current dwarf file number when generate dwarf debugging info for
105    /// assembly source files.
106    unsigned GenDwarfFileNumber;
107
108    /// The default initial text section that we generate dwarf debugging line
109    /// info for when generating dwarf assembly source files.
110    const MCSection *GenDwarfSection;
111
112    /// Honor temporary labels, this is useful for debugging semantic
113    /// differences between temporary and non-temporary labels (primarily on
114    /// Darwin).
115    bool AllowTemporaryLabels;
116
117    /// The dwarf line information from the .loc directives for the sections
118    /// with assembled machine instructions have after seeing .loc directives.
119    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
120    /// We need a deterministic iteration order, so we remember the order
121    /// the elements were added.
122    std::vector<const MCSection *> MCLineSectionOrder;
123
124    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
125
126    MCSymbol *CreateSymbol(StringRef Name);
127
128  public:
129    explicit MCContext(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
130                       const MCObjectFileInfo *MOFI);
131    ~MCContext();
132
133    const MCAsmInfo &getAsmInfo() const { return MAI; }
134
135    const MCRegisterInfo &getRegisterInfo() const { return MRI; }
136
137    const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }
138
139    void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
140
141    /// @name Symbol Management
142    /// @{
143
144    /// CreateTempSymbol - Create and return a new assembler temporary symbol
145    /// with a unique but unspecified name.
146    MCSymbol *CreateTempSymbol();
147
148    /// CreateDirectionalLocalSymbol - Create the definition of a directional
149    /// local symbol for numbered label (used for "1:" definitions).
150    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
151
152    /// GetDirectionalLocalSymbol - Create and return a directional local
153    /// symbol for numbered label (used for "1b" or 1f" references).
154    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
155
156    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
157    /// @p Name.  If it exists, return it.  If not, create a forward
158    /// reference and return it.
159    ///
160    /// @param Name - The symbol name, which must be unique across all symbols.
161    MCSymbol *GetOrCreateSymbol(StringRef Name);
162    MCSymbol *GetOrCreateSymbol(const Twine &Name);
163
164    /// LookupSymbol - Get the symbol for \p Name, or null.
165    MCSymbol *LookupSymbol(StringRef Name) const;
166
167    /// getSymbols - Get a reference for the symbol table for clients that
168    /// want to, for example, iterate over all symbols. 'const' because we
169    /// still want any modifications to the table itself to use the MCContext
170    /// APIs.
171    const SymbolTable &getSymbols() const {
172      return Symbols;
173    }
174
175    /// @}
176
177    /// @name Section Management
178    /// @{
179
180    /// getMachOSection - Return the MCSection for the specified mach-o section.
181    /// This requires the operands to be valid.
182    const MCSectionMachO *getMachOSection(StringRef Segment,
183                                          StringRef Section,
184                                          unsigned TypeAndAttributes,
185                                          unsigned Reserved2,
186                                          SectionKind K);
187    const MCSectionMachO *getMachOSection(StringRef Segment,
188                                          StringRef Section,
189                                          unsigned TypeAndAttributes,
190                                          SectionKind K) {
191      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
192    }
193
194    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
195                                      unsigned Flags, SectionKind Kind);
196
197    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
198                                      unsigned Flags, SectionKind Kind,
199                                      unsigned EntrySize, StringRef Group);
200
201    const MCSectionELF *CreateELFGroupSection();
202
203    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
204                                    int Selection, SectionKind Kind);
205
206    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
207                                    SectionKind Kind) {
208      return getCOFFSection (Section, Characteristics, 0, Kind);
209    }
210
211
212    /// @}
213
214    /// @name Dwarf Management
215    /// @{
216
217    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
218    unsigned GetDwarfFile(StringRef Directory, StringRef FileName,
219                          unsigned FileNumber);
220
221    bool isValidDwarfFileNumber(unsigned FileNumber);
222
223    bool hasDwarfFiles() const {
224      return !MCDwarfFiles.empty();
225    }
226
227    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
228      return MCDwarfFiles;
229    }
230    const std::vector<StringRef> &getMCDwarfDirs() {
231      return MCDwarfDirs;
232    }
233
234    const DenseMap<const MCSection *, MCLineSection *>
235    &getMCLineSections() const {
236      return MCLineSections;
237    }
238    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
239      return MCLineSectionOrder;
240    }
241    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
242      MCLineSections[Sec] = Line;
243      MCLineSectionOrder.push_back(Sec);
244    }
245
246    /// setCurrentDwarfLoc - saves the information from the currently parsed
247    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
248    /// is assembled an entry in the line number table with this information and
249    /// the address of the instruction will be created.
250    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
251                            unsigned Flags, unsigned Isa,
252                            unsigned Discriminator) {
253      CurrentDwarfLoc.setFileNum(FileNum);
254      CurrentDwarfLoc.setLine(Line);
255      CurrentDwarfLoc.setColumn(Column);
256      CurrentDwarfLoc.setFlags(Flags);
257      CurrentDwarfLoc.setIsa(Isa);
258      CurrentDwarfLoc.setDiscriminator(Discriminator);
259      DwarfLocSeen = true;
260    }
261    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
262
263    bool getDwarfLocSeen() { return DwarfLocSeen; }
264    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
265
266    bool getGenDwarfForAssembly() { return GenDwarfForAssembly; }
267    void setGenDwarfForAssembly(bool Value) { GenDwarfForAssembly = Value; }
268    unsigned getGenDwarfFileNumber() { return GenDwarfFileNumber; }
269    unsigned nextGenDwarfFileNumber() { return ++GenDwarfFileNumber; }
270    const MCSection *getGenDwarfSection() { return GenDwarfSection; }
271    void setGenDwarfSection(const MCSection *Sec) { GenDwarfSection = Sec; }
272
273    /// @}
274
275    char *getSecureLogFile() { return SecureLogFile; }
276    raw_ostream *getSecureLog() { return SecureLog; }
277    bool getSecureLogUsed() { return SecureLogUsed; }
278    void setSecureLog(raw_ostream *Value) {
279      SecureLog = Value;
280    }
281    void setSecureLogUsed(bool Value) {
282      SecureLogUsed = Value;
283    }
284
285    void *Allocate(unsigned Size, unsigned Align = 8) {
286      return Allocator.Allocate(Size, Align);
287    }
288    void Deallocate(void *Ptr) {
289    }
290  };
291
292} // end namespace llvm
293
294// operator new and delete aren't allowed inside namespaces.
295// The throw specifications are mandated by the standard.
296/// @brief Placement new for using the MCContext's allocator.
297///
298/// This placement form of operator new uses the MCContext's allocator for
299/// obtaining memory. It is a non-throwing new, which means that it returns
300/// null on error. (If that is what the allocator does. The current does, so if
301/// this ever changes, this operator will have to be changed, too.)
302/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
303/// @code
304/// // Default alignment (16)
305/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
306/// // Specific alignment
307/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
308/// @endcode
309/// Please note that you cannot use delete on the pointer; it must be
310/// deallocated using an explicit destructor call followed by
311/// @c Context.Deallocate(Ptr).
312///
313/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
314/// @param C The MCContext that provides the allocator.
315/// @param Alignment The alignment of the allocated memory (if the underlying
316///                  allocator supports it).
317/// @return The allocated memory. Could be NULL.
318inline void *operator new(size_t Bytes, llvm::MCContext &C,
319                          size_t Alignment = 16) throw () {
320  return C.Allocate(Bytes, Alignment);
321}
322/// @brief Placement delete companion to the new above.
323///
324/// This operator is just a companion to the new above. There is no way of
325/// invoking it directly; see the new operator for more details. This operator
326/// is called implicitly by the compiler if a placement new expression using
327/// the MCContext throws in the object constructor.
328inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
329              throw () {
330  C.Deallocate(Ptr);
331}
332
333/// This placement form of operator new[] uses the MCContext's allocator for
334/// obtaining memory. It is a non-throwing new[], which means that it returns
335/// null on error.
336/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
337/// @code
338/// // Default alignment (16)
339/// char *data = new (Context) char[10];
340/// // Specific alignment
341/// char *data = new (Context, 8) char[10];
342/// @endcode
343/// Please note that you cannot use delete on the pointer; it must be
344/// deallocated using an explicit destructor call followed by
345/// @c Context.Deallocate(Ptr).
346///
347/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
348/// @param C The MCContext that provides the allocator.
349/// @param Alignment The alignment of the allocated memory (if the underlying
350///                  allocator supports it).
351/// @return The allocated memory. Could be NULL.
352inline void *operator new[](size_t Bytes, llvm::MCContext& C,
353                            size_t Alignment = 16) throw () {
354  return C.Allocate(Bytes, Alignment);
355}
356
357/// @brief Placement delete[] companion to the new[] above.
358///
359/// This operator is just a companion to the new[] above. There is no way of
360/// invoking it directly; see the new[] operator for more details. This operator
361/// is called implicitly by the compiler if a placement new[] expression using
362/// the MCContext throws in the object constructor.
363inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
364  C.Deallocate(Ptr);
365}
366
367#endif
368