MCContext.h revision e82b8eeaa2d36ee52690ae19bca9735629b6003e 
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 MCLineSection;
30  class StringRef;
31  class Twine;
32  class TargetAsmInfo;
33  class MCSectionMachO;
34  class MCSectionELF;
35
36  /// MCContext - Context object for machine code objects.  This class owns all
37  /// of the sections that it creates.
38  ///
39  class MCContext {
40    MCContext(const MCContext&); // DO NOT IMPLEMENT
41    MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
42  public:
43    typedef StringMap<MCSymbol*, BumpPtrAllocator&> SymbolTable;
44  private:
45
46    /// The MCAsmInfo for this target.
47    const MCAsmInfo &MAI;
48
49    const TargetAsmInfo *TAI;
50
51    /// Allocator - Allocator object used for creating machine code objects.
52    ///
53    /// We use a bump pointer allocator to avoid the need to track all allocated
54    /// objects.
55    BumpPtrAllocator Allocator;
56
57    /// Symbols - Bindings of names to symbols.
58    SymbolTable Symbols;
59
60    /// UsedNames - Keeps tracks of names that were used both for used declared
61    /// and artificial symbols.
62    StringMap<bool, BumpPtrAllocator&> UsedNames;
63
64    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
65    /// symbol.
66    unsigned NextUniqueID;
67
68    /// Instances of directional local labels.
69    DenseMap<unsigned, MCLabel *> Instances;
70    /// NextInstance() creates the next instance of the directional local label
71    /// for the LocalLabelVal and adds it to the map if needed.
72    unsigned NextInstance(int64_t LocalLabelVal);
73    /// GetInstance() gets the current instance of the directional local label
74    /// for the LocalLabelVal and adds it to the map if needed.
75    unsigned GetInstance(int64_t LocalLabelVal);
76
77    /// The file name of the log file from the environment variable
78    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
79    /// directive is used or it is an error.
80    char *SecureLogFile;
81    /// The stream that gets written to for the .secure_log_unique directive.
82    raw_ostream *SecureLog;
83    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
84    /// catch errors if .secure_log_unique appears twice without
85    /// .secure_log_reset appearing between them.
86    bool SecureLogUsed;
87
88    /// The dwarf file and directory tables from the dwarf .file directive.
89    std::vector<MCDwarfFile *> MCDwarfFiles;
90    std::vector<StringRef> MCDwarfDirs;
91
92    /// The current dwarf line information from the last dwarf .loc directive.
93    MCDwarfLoc CurrentDwarfLoc;
94    bool DwarfLocSeen;
95
96    /// Honor temporary labels, this is useful for debugging semantic
97    /// differences between temporary and non-temporary labels (primarily on
98    /// Darwin).
99    bool AllowTemporaryLabels;
100
101    /// The dwarf line information from the .loc directives for the sections
102    /// with assembled machine instructions have after seeing .loc directives.
103    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
104    /// We need a deterministic iteration order, so we remember the order
105    /// the elements were added.
106    std::vector<const MCSection *> MCLineSectionOrder;
107
108    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
109
110    MCSymbol *CreateSymbol(StringRef Name);
111
112  public:
113    explicit MCContext(const MCAsmInfo &MAI, const TargetAsmInfo *TAI);
114    ~MCContext();
115
116    const MCAsmInfo &getAsmInfo() const { return MAI; }
117
118    const TargetAsmInfo &getTargetAsmInfo() const { return *TAI; }
119
120    void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
121
122    /// @name Symbol Management
123    /// @{
124
125    /// CreateTempSymbol - Create and return a new assembler temporary symbol
126    /// with a unique but unspecified name.
127    MCSymbol *CreateTempSymbol();
128
129    /// CreateDirectionalLocalSymbol - Create the definition of a directional
130    /// local symbol for numbered label (used for "1:" definitions).
131    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
132
133    /// GetDirectionalLocalSymbol - Create and return a directional local
134    /// symbol for numbered label (used for "1b" or 1f" references).
135    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
136
137    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
138    /// @p Name.  If it exists, return it.  If not, create a forward
139    /// reference and return it.
140    ///
141    /// @param Name - The symbol name, which must be unique across all symbols.
142    MCSymbol *GetOrCreateSymbol(StringRef Name);
143    MCSymbol *GetOrCreateSymbol(const Twine &Name);
144
145    /// LookupSymbol - Get the symbol for \p Name, or null.
146    MCSymbol *LookupSymbol(StringRef Name) const;
147
148    /// getSymbols - Get a reference for the symbol table for clients that
149    /// want to, for example, iterate over all symbols. 'const' because we
150    /// still want any modifications to the table itself to use the MCContext
151    /// APIs.
152    const SymbolTable &getSymbols() const {
153      return Symbols;
154    }
155
156    /// @}
157
158    /// @name Section Management
159    /// @{
160
161    /// getMachOSection - Return the MCSection for the specified mach-o section.
162    /// This requires the operands to be valid.
163    const MCSectionMachO *getMachOSection(StringRef Segment,
164                                          StringRef Section,
165                                          unsigned TypeAndAttributes,
166                                          unsigned Reserved2,
167                                          SectionKind K);
168    const MCSectionMachO *getMachOSection(StringRef Segment,
169                                          StringRef Section,
170                                          unsigned TypeAndAttributes,
171                                          SectionKind K) {
172      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
173    }
174
175    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
176                                      unsigned Flags, SectionKind Kind);
177
178    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
179                                      unsigned Flags, SectionKind Kind,
180                                      unsigned EntrySize, StringRef Group);
181
182    const MCSectionELF *CreateELFGroupSection();
183
184    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
185                                    int Selection, SectionKind Kind);
186
187    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
188                                    SectionKind Kind) {
189      return getCOFFSection (Section, Characteristics, 0, Kind);
190    }
191
192
193    /// @}
194
195    /// @name Dwarf Management
196    /// @{
197
198    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
199    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
200
201    bool isValidDwarfFileNumber(unsigned FileNumber);
202
203    bool hasDwarfFiles() const {
204      return !MCDwarfFiles.empty();
205    }
206
207    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
208      return MCDwarfFiles;
209    }
210    const std::vector<StringRef> &getMCDwarfDirs() {
211      return MCDwarfDirs;
212    }
213
214    const DenseMap<const MCSection *, MCLineSection *>
215    &getMCLineSections() const {
216      return MCLineSections;
217    }
218    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
219      return MCLineSectionOrder;
220    }
221    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
222      MCLineSections[Sec] = Line;
223      MCLineSectionOrder.push_back(Sec);
224    }
225
226    /// setCurrentDwarfLoc - saves the information from the currently parsed
227    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
228    /// is assembled an entry in the line number table with this information and
229    /// the address of the instruction will be created.
230    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
231                            unsigned Flags, unsigned Isa,
232                            unsigned Discriminator) {
233      CurrentDwarfLoc.setFileNum(FileNum);
234      CurrentDwarfLoc.setLine(Line);
235      CurrentDwarfLoc.setColumn(Column);
236      CurrentDwarfLoc.setFlags(Flags);
237      CurrentDwarfLoc.setIsa(Isa);
238      CurrentDwarfLoc.setDiscriminator(Discriminator);
239      DwarfLocSeen = true;
240    }
241    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
242
243    bool getDwarfLocSeen() { return DwarfLocSeen; }
244    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
245
246    /// @}
247
248    char *getSecureLogFile() { return SecureLogFile; }
249    raw_ostream *getSecureLog() { return SecureLog; }
250    bool getSecureLogUsed() { return SecureLogUsed; }
251    void setSecureLog(raw_ostream *Value) {
252      SecureLog = Value;
253    }
254    void setSecureLogUsed(bool Value) {
255      SecureLogUsed = Value;
256    }
257
258    void *Allocate(unsigned Size, unsigned Align = 8) {
259      return Allocator.Allocate(Size, Align);
260    }
261    void Deallocate(void *Ptr) {
262    }
263  };
264
265} // end namespace llvm
266
267// operator new and delete aren't allowed inside namespaces.
268// The throw specifications are mandated by the standard.
269/// @brief Placement new for using the MCContext's allocator.
270///
271/// This placement form of operator new uses the MCContext's allocator for
272/// obtaining memory. It is a non-throwing new, which means that it returns
273/// null on error. (If that is what the allocator does. The current does, so if
274/// this ever changes, this operator will have to be changed, too.)
275/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
276/// @code
277/// // Default alignment (16)
278/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
279/// // Specific alignment
280/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
281/// @endcode
282/// Please note that you cannot use delete on the pointer; it must be
283/// deallocated using an explicit destructor call followed by
284/// @c Context.Deallocate(Ptr).
285///
286/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
287/// @param C The MCContext that provides the allocator.
288/// @param Alignment The alignment of the allocated memory (if the underlying
289///                  allocator supports it).
290/// @return The allocated memory. Could be NULL.
291inline void *operator new(size_t Bytes, llvm::MCContext &C,
292                          size_t Alignment = 16) throw () {
293  return C.Allocate(Bytes, Alignment);
294}
295/// @brief Placement delete companion to the new above.
296///
297/// This operator is just a companion to the new above. There is no way of
298/// invoking it directly; see the new operator for more details. This operator
299/// is called implicitly by the compiler if a placement new expression using
300/// the MCContext throws in the object constructor.
301inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
302              throw () {
303  C.Deallocate(Ptr);
304}
305
306/// This placement form of operator new[] uses the MCContext's allocator for
307/// obtaining memory. It is a non-throwing new[], which means that it returns
308/// null on error.
309/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
310/// @code
311/// // Default alignment (16)
312/// char *data = new (Context) char[10];
313/// // Specific alignment
314/// char *data = new (Context, 8) char[10];
315/// @endcode
316/// Please note that you cannot use delete on the pointer; it must be
317/// deallocated using an explicit destructor call followed by
318/// @c Context.Deallocate(Ptr).
319///
320/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
321/// @param C The MCContext that provides the allocator.
322/// @param Alignment The alignment of the allocated memory (if the underlying
323///                  allocator supports it).
324/// @return The allocated memory. Could be NULL.
325inline void *operator new[](size_t Bytes, llvm::MCContext& C,
326                            size_t Alignment = 16) throw () {
327  return C.Allocate(Bytes, Alignment);
328}
329
330/// @brief Placement delete[] companion to the new[] above.
331///
332/// This operator is just a companion to the new[] above. There is no way of
333/// invoking it directly; see the new[] operator for more details. This operator
334/// is called implicitly by the compiler if a placement new[] expression using
335/// the MCContext throws in the object constructor.
336inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
337  C.Deallocate(Ptr);
338}
339
340#endif
341