MCContext.h revision e76a33b9567d78a5744dc52fcec3a6056d6fb576 
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 TargetAsmInfo;
35  class MCSectionMachO;
36  class MCSectionELF;
37
38  /// MCContext - Context object for machine code objects.  This class owns all
39  /// of the sections that it creates.
40  ///
41  class MCContext {
42    MCContext(const MCContext&); // DO NOT IMPLEMENT
43    MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
44  public:
45    typedef StringMap<MCSymbol*, BumpPtrAllocator&> SymbolTable;
46  private:
47
48    /// The MCAsmInfo for this target.
49    const MCAsmInfo &MAI;
50
51    /// The MCRegisterInfo for this target.
52    const MCRegisterInfo &MRI;
53
54    /// The MCObjectFileInfo for this target.
55    const MCObjectFileInfo *MOFI;
56
57    const TargetAsmInfo *TAI;
58
59    /// Allocator - Allocator object used for creating machine code objects.
60    ///
61    /// We use a bump pointer allocator to avoid the need to track all allocated
62    /// objects.
63    BumpPtrAllocator Allocator;
64
65    /// Symbols - Bindings of names to symbols.
66    SymbolTable Symbols;
67
68    /// UsedNames - Keeps tracks of names that were used both for used declared
69    /// and artificial symbols.
70    StringMap<bool, BumpPtrAllocator&> UsedNames;
71
72    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
73    /// symbol.
74    unsigned NextUniqueID;
75
76    /// Instances of directional local labels.
77    DenseMap<unsigned, MCLabel *> Instances;
78    /// NextInstance() creates the next instance of the directional local label
79    /// for the LocalLabelVal and adds it to the map if needed.
80    unsigned NextInstance(int64_t LocalLabelVal);
81    /// GetInstance() gets the current instance of the directional local label
82    /// for the LocalLabelVal and adds it to the map if needed.
83    unsigned GetInstance(int64_t LocalLabelVal);
84
85    /// The file name of the log file from the environment variable
86    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
87    /// directive is used or it is an error.
88    char *SecureLogFile;
89    /// The stream that gets written to for the .secure_log_unique directive.
90    raw_ostream *SecureLog;
91    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
92    /// catch errors if .secure_log_unique appears twice without
93    /// .secure_log_reset appearing between them.
94    bool SecureLogUsed;
95
96    /// The dwarf file and directory tables from the dwarf .file directive.
97    std::vector<MCDwarfFile *> MCDwarfFiles;
98    std::vector<StringRef> MCDwarfDirs;
99
100    /// The current dwarf line information from the last dwarf .loc directive.
101    MCDwarfLoc CurrentDwarfLoc;
102    bool DwarfLocSeen;
103
104    /// Honor temporary labels, this is useful for debugging semantic
105    /// differences between temporary and non-temporary labels (primarily on
106    /// Darwin).
107    bool AllowTemporaryLabels;
108
109    /// The dwarf line information from the .loc directives for the sections
110    /// with assembled machine instructions have after seeing .loc directives.
111    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
112    /// We need a deterministic iteration order, so we remember the order
113    /// the elements were added.
114    std::vector<const MCSection *> MCLineSectionOrder;
115
116    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
117
118    MCSymbol *CreateSymbol(StringRef Name);
119
120  public:
121    explicit MCContext(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
122                       const MCObjectFileInfo *MOFI, const TargetAsmInfo *TAI);
123    ~MCContext();
124
125    const MCAsmInfo &getAsmInfo() const { return MAI; }
126
127    const MCRegisterInfo &getRegisterInfo() const { return MRI; }
128
129    const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }
130
131    const TargetAsmInfo &getTargetAsmInfo() const { return *TAI; }
132
133    void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
134
135    /// @name Symbol Management
136    /// @{
137
138    /// CreateTempSymbol - Create and return a new assembler temporary symbol
139    /// with a unique but unspecified name.
140    MCSymbol *CreateTempSymbol();
141
142    /// CreateDirectionalLocalSymbol - Create the definition of a directional
143    /// local symbol for numbered label (used for "1:" definitions).
144    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
145
146    /// GetDirectionalLocalSymbol - Create and return a directional local
147    /// symbol for numbered label (used for "1b" or 1f" references).
148    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
149
150    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
151    /// @p Name.  If it exists, return it.  If not, create a forward
152    /// reference and return it.
153    ///
154    /// @param Name - The symbol name, which must be unique across all symbols.
155    MCSymbol *GetOrCreateSymbol(StringRef Name);
156    MCSymbol *GetOrCreateSymbol(const Twine &Name);
157
158    /// LookupSymbol - Get the symbol for \p Name, or null.
159    MCSymbol *LookupSymbol(StringRef Name) const;
160
161    /// getSymbols - Get a reference for the symbol table for clients that
162    /// want to, for example, iterate over all symbols. 'const' because we
163    /// still want any modifications to the table itself to use the MCContext
164    /// APIs.
165    const SymbolTable &getSymbols() const {
166      return Symbols;
167    }
168
169    /// @}
170
171    /// @name Section Management
172    /// @{
173
174    /// getMachOSection - Return the MCSection for the specified mach-o section.
175    /// This requires the operands to be valid.
176    const MCSectionMachO *getMachOSection(StringRef Segment,
177                                          StringRef Section,
178                                          unsigned TypeAndAttributes,
179                                          unsigned Reserved2,
180                                          SectionKind K);
181    const MCSectionMachO *getMachOSection(StringRef Segment,
182                                          StringRef Section,
183                                          unsigned TypeAndAttributes,
184                                          SectionKind K) {
185      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
186    }
187
188    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
189                                      unsigned Flags, SectionKind Kind);
190
191    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
192                                      unsigned Flags, SectionKind Kind,
193                                      unsigned EntrySize, StringRef Group);
194
195    const MCSectionELF *CreateELFGroupSection();
196
197    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
198                                    int Selection, SectionKind Kind);
199
200    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
201                                    SectionKind Kind) {
202      return getCOFFSection (Section, Characteristics, 0, Kind);
203    }
204
205
206    /// @}
207
208    /// @name Dwarf Management
209    /// @{
210
211    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
212    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
213
214    bool isValidDwarfFileNumber(unsigned FileNumber);
215
216    bool hasDwarfFiles() const {
217      return !MCDwarfFiles.empty();
218    }
219
220    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
221      return MCDwarfFiles;
222    }
223    const std::vector<StringRef> &getMCDwarfDirs() {
224      return MCDwarfDirs;
225    }
226
227    const DenseMap<const MCSection *, MCLineSection *>
228    &getMCLineSections() const {
229      return MCLineSections;
230    }
231    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
232      return MCLineSectionOrder;
233    }
234    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
235      MCLineSections[Sec] = Line;
236      MCLineSectionOrder.push_back(Sec);
237    }
238
239    /// setCurrentDwarfLoc - saves the information from the currently parsed
240    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
241    /// is assembled an entry in the line number table with this information and
242    /// the address of the instruction will be created.
243    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
244                            unsigned Flags, unsigned Isa,
245                            unsigned Discriminator) {
246      CurrentDwarfLoc.setFileNum(FileNum);
247      CurrentDwarfLoc.setLine(Line);
248      CurrentDwarfLoc.setColumn(Column);
249      CurrentDwarfLoc.setFlags(Flags);
250      CurrentDwarfLoc.setIsa(Isa);
251      CurrentDwarfLoc.setDiscriminator(Discriminator);
252      DwarfLocSeen = true;
253    }
254    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
255
256    bool getDwarfLocSeen() { return DwarfLocSeen; }
257    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
258
259    /// @}
260
261    char *getSecureLogFile() { return SecureLogFile; }
262    raw_ostream *getSecureLog() { return SecureLog; }
263    bool getSecureLogUsed() { return SecureLogUsed; }
264    void setSecureLog(raw_ostream *Value) {
265      SecureLog = Value;
266    }
267    void setSecureLogUsed(bool Value) {
268      SecureLogUsed = Value;
269    }
270
271    void *Allocate(unsigned Size, unsigned Align = 8) {
272      return Allocator.Allocate(Size, Align);
273    }
274    void Deallocate(void *Ptr) {
275    }
276  };
277
278} // end namespace llvm
279
280// operator new and delete aren't allowed inside namespaces.
281// The throw specifications are mandated by the standard.
282/// @brief Placement new for using the MCContext's allocator.
283///
284/// This placement form of operator new uses the MCContext's allocator for
285/// obtaining memory. It is a non-throwing new, which means that it returns
286/// null on error. (If that is what the allocator does. The current does, so if
287/// this ever changes, this operator will have to be changed, too.)
288/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
289/// @code
290/// // Default alignment (16)
291/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
292/// // Specific alignment
293/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
294/// @endcode
295/// Please note that you cannot use delete on the pointer; it must be
296/// deallocated using an explicit destructor call followed by
297/// @c Context.Deallocate(Ptr).
298///
299/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
300/// @param C The MCContext that provides the allocator.
301/// @param Alignment The alignment of the allocated memory (if the underlying
302///                  allocator supports it).
303/// @return The allocated memory. Could be NULL.
304inline void *operator new(size_t Bytes, llvm::MCContext &C,
305                          size_t Alignment = 16) throw () {
306  return C.Allocate(Bytes, Alignment);
307}
308/// @brief Placement delete companion to the new above.
309///
310/// This operator is just a companion to the new above. There is no way of
311/// invoking it directly; see the new operator for more details. This operator
312/// is called implicitly by the compiler if a placement new expression using
313/// the MCContext throws in the object constructor.
314inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
315              throw () {
316  C.Deallocate(Ptr);
317}
318
319/// This placement form of operator new[] uses the MCContext's allocator for
320/// obtaining memory. It is a non-throwing new[], which means that it returns
321/// null on error.
322/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
323/// @code
324/// // Default alignment (16)
325/// char *data = new (Context) char[10];
326/// // Specific alignment
327/// char *data = new (Context, 8) char[10];
328/// @endcode
329/// Please note that you cannot use delete on the pointer; it must be
330/// deallocated using an explicit destructor call followed by
331/// @c Context.Deallocate(Ptr).
332///
333/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
334/// @param C The MCContext that provides the allocator.
335/// @param Alignment The alignment of the allocated memory (if the underlying
336///                  allocator supports it).
337/// @return The allocated memory. Could be NULL.
338inline void *operator new[](size_t Bytes, llvm::MCContext& C,
339                            size_t Alignment = 16) throw () {
340  return C.Allocate(Bytes, Alignment);
341}
342
343/// @brief Placement delete[] companion to the new[] above.
344///
345/// This operator is just a companion to the new[] above. There is no way of
346/// invoking it directly; see the new[] operator for more details. This operator
347/// is called implicitly by the compiler if a placement new[] expression using
348/// the MCContext throws in the object constructor.
349inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
350  C.Deallocate(Ptr);
351}
352
353#endif
354