MCContext.h revision 44d798d9763bc32aaf49fe7c10d604845f4b6685 
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    /// Honor temporary labels, this is useful for debugging semantic
102    /// differences between temporary and non-temporary labels (primarily on
103    /// Darwin).
104    bool AllowTemporaryLabels;
105
106    /// The dwarf line information from the .loc directives for the sections
107    /// with assembled machine instructions have after seeing .loc directives.
108    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
109    /// We need a deterministic iteration order, so we remember the order
110    /// the elements were added.
111    std::vector<const MCSection *> MCLineSectionOrder;
112
113    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
114
115    MCSymbol *CreateSymbol(StringRef Name);
116
117  public:
118    explicit MCContext(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
119                       const MCObjectFileInfo *MOFI);
120    ~MCContext();
121
122    const MCAsmInfo &getAsmInfo() const { return MAI; }
123
124    const MCRegisterInfo &getRegisterInfo() const { return MRI; }
125
126    const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }
127
128    void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
129
130    /// @name Symbol Management
131    /// @{
132
133    /// CreateTempSymbol - Create and return a new assembler temporary symbol
134    /// with a unique but unspecified name.
135    MCSymbol *CreateTempSymbol();
136
137    /// CreateDirectionalLocalSymbol - Create the definition of a directional
138    /// local symbol for numbered label (used for "1:" definitions).
139    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
140
141    /// GetDirectionalLocalSymbol - Create and return a directional local
142    /// symbol for numbered label (used for "1b" or 1f" references).
143    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
144
145    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
146    /// @p Name.  If it exists, return it.  If not, create a forward
147    /// reference and return it.
148    ///
149    /// @param Name - The symbol name, which must be unique across all symbols.
150    MCSymbol *GetOrCreateSymbol(StringRef Name);
151    MCSymbol *GetOrCreateSymbol(const Twine &Name);
152
153    /// LookupSymbol - Get the symbol for \p Name, or null.
154    MCSymbol *LookupSymbol(StringRef Name) const;
155
156    /// getSymbols - Get a reference for the symbol table for clients that
157    /// want to, for example, iterate over all symbols. 'const' because we
158    /// still want any modifications to the table itself to use the MCContext
159    /// APIs.
160    const SymbolTable &getSymbols() const {
161      return Symbols;
162    }
163
164    /// @}
165
166    /// @name Section Management
167    /// @{
168
169    /// getMachOSection - Return the MCSection for the specified mach-o section.
170    /// This requires the operands to be valid.
171    const MCSectionMachO *getMachOSection(StringRef Segment,
172                                          StringRef Section,
173                                          unsigned TypeAndAttributes,
174                                          unsigned Reserved2,
175                                          SectionKind K);
176    const MCSectionMachO *getMachOSection(StringRef Segment,
177                                          StringRef Section,
178                                          unsigned TypeAndAttributes,
179                                          SectionKind K) {
180      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
181    }
182
183    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
184                                      unsigned Flags, SectionKind Kind);
185
186    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
187                                      unsigned Flags, SectionKind Kind,
188                                      unsigned EntrySize, StringRef Group);
189
190    const MCSectionELF *CreateELFGroupSection();
191
192    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
193                                    int Selection, SectionKind Kind);
194
195    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
196                                    SectionKind Kind) {
197      return getCOFFSection (Section, Characteristics, 0, Kind);
198    }
199
200
201    /// @}
202
203    /// @name Dwarf Management
204    /// @{
205
206    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
207    unsigned GetDwarfFile(StringRef Directory, StringRef FileName,
208                          unsigned FileNumber);
209
210    bool isValidDwarfFileNumber(unsigned FileNumber);
211
212    bool hasDwarfFiles() const {
213      return !MCDwarfFiles.empty();
214    }
215
216    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
217      return MCDwarfFiles;
218    }
219    const std::vector<StringRef> &getMCDwarfDirs() {
220      return MCDwarfDirs;
221    }
222
223    const DenseMap<const MCSection *, MCLineSection *>
224    &getMCLineSections() const {
225      return MCLineSections;
226    }
227    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
228      return MCLineSectionOrder;
229    }
230    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
231      MCLineSections[Sec] = Line;
232      MCLineSectionOrder.push_back(Sec);
233    }
234
235    /// setCurrentDwarfLoc - saves the information from the currently parsed
236    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
237    /// is assembled an entry in the line number table with this information and
238    /// the address of the instruction will be created.
239    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
240                            unsigned Flags, unsigned Isa,
241                            unsigned Discriminator) {
242      CurrentDwarfLoc.setFileNum(FileNum);
243      CurrentDwarfLoc.setLine(Line);
244      CurrentDwarfLoc.setColumn(Column);
245      CurrentDwarfLoc.setFlags(Flags);
246      CurrentDwarfLoc.setIsa(Isa);
247      CurrentDwarfLoc.setDiscriminator(Discriminator);
248      DwarfLocSeen = true;
249    }
250    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
251
252    bool getDwarfLocSeen() { return DwarfLocSeen; }
253    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
254
255    /// @}
256
257    char *getSecureLogFile() { return SecureLogFile; }
258    raw_ostream *getSecureLog() { return SecureLog; }
259    bool getSecureLogUsed() { return SecureLogUsed; }
260    void setSecureLog(raw_ostream *Value) {
261      SecureLog = Value;
262    }
263    void setSecureLogUsed(bool Value) {
264      SecureLogUsed = Value;
265    }
266
267    void *Allocate(unsigned Size, unsigned Align = 8) {
268      return Allocator.Allocate(Size, Align);
269    }
270    void Deallocate(void *Ptr) {
271    }
272  };
273
274} // end namespace llvm
275
276// operator new and delete aren't allowed inside namespaces.
277// The throw specifications are mandated by the standard.
278/// @brief Placement new for using the MCContext's allocator.
279///
280/// This placement form of operator new uses the MCContext's allocator for
281/// obtaining memory. It is a non-throwing new, which means that it returns
282/// null on error. (If that is what the allocator does. The current does, so if
283/// this ever changes, this operator will have to be changed, too.)
284/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
285/// @code
286/// // Default alignment (16)
287/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
288/// // Specific alignment
289/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
290/// @endcode
291/// Please note that you cannot use delete on the pointer; it must be
292/// deallocated using an explicit destructor call followed by
293/// @c Context.Deallocate(Ptr).
294///
295/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
296/// @param C The MCContext that provides the allocator.
297/// @param Alignment The alignment of the allocated memory (if the underlying
298///                  allocator supports it).
299/// @return The allocated memory. Could be NULL.
300inline void *operator new(size_t Bytes, llvm::MCContext &C,
301                          size_t Alignment = 16) throw () {
302  return C.Allocate(Bytes, Alignment);
303}
304/// @brief Placement delete companion to the new above.
305///
306/// This operator is just a companion to the new above. There is no way of
307/// invoking it directly; see the new operator for more details. This operator
308/// is called implicitly by the compiler if a placement new expression using
309/// the MCContext throws in the object constructor.
310inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
311              throw () {
312  C.Deallocate(Ptr);
313}
314
315/// This placement form of operator new[] uses the MCContext's allocator for
316/// obtaining memory. It is a non-throwing new[], which means that it returns
317/// null on error.
318/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
319/// @code
320/// // Default alignment (16)
321/// char *data = new (Context) char[10];
322/// // Specific alignment
323/// char *data = new (Context, 8) char[10];
324/// @endcode
325/// Please note that you cannot use delete on the pointer; it must be
326/// deallocated using an explicit destructor call followed by
327/// @c Context.Deallocate(Ptr).
328///
329/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
330/// @param C The MCContext that provides the allocator.
331/// @param Alignment The alignment of the allocated memory (if the underlying
332///                  allocator supports it).
333/// @return The allocated memory. Could be NULL.
334inline void *operator new[](size_t Bytes, llvm::MCContext& C,
335                            size_t Alignment = 16) throw () {
336  return C.Allocate(Bytes, Alignment);
337}
338
339/// @brief Placement delete[] companion to the new[] above.
340///
341/// This operator is just a companion to the new[] above. There is no way of
342/// invoking it directly; see the new[] operator for more details. This operator
343/// is called implicitly by the compiler if a placement new[] expression using
344/// the MCContext throws in the object constructor.
345inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
346  C.Deallocate(Ptr);
347}
348
349#endif
350