MCContext.h revision 326990f1eb7ff005adabe46a1f982eff8835813e 
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 MCSectionMachO;
33  class MCSectionELF;
34
35  /// MCContext - Context object for machine code objects.  This class owns all
36  /// of the sections that it creates.
37  ///
38  class MCContext {
39    MCContext(const MCContext&); // DO NOT IMPLEMENT
40    MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
41
42    /// The MCAsmInfo for this target.
43    const MCAsmInfo &MAI;
44
45    /// Symbols - Bindings of names to symbols.
46    StringMap<MCSymbol*> Symbols;
47
48    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
49    /// symbol.
50    unsigned NextUniqueID;
51
52    /// Instances of directional local labels.
53    DenseMap<unsigned, MCLabel *> Instances;
54    /// NextInstance() creates the next instance of the directional local label
55    /// for the LocalLabelVal and adds it to the map if needed.
56    unsigned NextInstance(int64_t LocalLabelVal);
57    /// GetInstance() gets the current instance of the directional local label
58    /// for the LocalLabelVal and adds it to the map if needed.
59    unsigned GetInstance(int64_t LocalLabelVal);
60
61    /// The file name of the log file from the environment variable
62    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
63    /// directive is used or it is an error.
64    char *SecureLogFile;
65    /// The stream that gets written to for the .secure_log_unique directive.
66    raw_ostream *SecureLog;
67    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
68    /// catch errors if .secure_log_unique appears twice without
69    /// .secure_log_reset appearing between them.
70    bool SecureLogUsed;
71
72    /// The dwarf file and directory tables from the dwarf .file directive.
73    std::vector<MCDwarfFile *> MCDwarfFiles;
74    std::vector<StringRef> MCDwarfDirs;
75
76    /// The current dwarf line information from the last dwarf .loc directive.
77    MCDwarfLoc CurrentDwarfLoc;
78    bool DwarfLocSeen;
79
80    /// The dwarf line information from the .loc directives for the sections
81    /// with assembled machine instructions have after seeing .loc directives.
82    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
83    /// We need a deterministic iteration order, so we remember the order
84    /// the elements were added.
85    std::vector<const MCSection *> MCLineSectionOrder;
86
87    /// Allocator - Allocator object used for creating machine code objects.
88    ///
89    /// We use a bump pointer allocator to avoid the need to track all allocated
90    /// objects.
91    BumpPtrAllocator Allocator;
92
93    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
94  public:
95    explicit MCContext(const MCAsmInfo &MAI);
96    ~MCContext();
97
98    const MCAsmInfo &getAsmInfo() const { return MAI; }
99
100    /// @name Symbol Management
101    /// @{
102
103    /// CreateTempSymbol - Create and return a new assembler temporary symbol
104    /// with a unique but unspecified name.
105    MCSymbol *CreateTempSymbol();
106
107    /// CreateDirectionalLocalSymbol - Create the definition of a directional
108    /// local symbol for numbered label (used for "1:" definitions).
109    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
110
111    /// GetDirectionalLocalSymbol - Create and return a directional local
112    /// symbol for numbered label (used for "1b" or 1f" references).
113    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
114
115    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
116    /// @p Name.  If it exists, return it.  If not, create a forward
117    /// reference and return it.
118    ///
119    /// @param Name - The symbol name, which must be unique across all symbols.
120    MCSymbol *GetOrCreateSymbol(StringRef Name);
121    MCSymbol *GetOrCreateSymbol(const Twine &Name);
122
123    /// LookupSymbol - Get the symbol for \p Name, or null.
124    MCSymbol *LookupSymbol(StringRef Name) const;
125
126    /// @}
127
128    /// @name Section Management
129    /// @{
130
131    /// getMachOSection - Return the MCSection for the specified mach-o section.
132    /// This requires the operands to be valid.
133    const MCSectionMachO *getMachOSection(StringRef Segment,
134                                          StringRef Section,
135                                          unsigned TypeAndAttributes,
136                                          unsigned Reserved2,
137                                          SectionKind K);
138    const MCSectionMachO *getMachOSection(StringRef Segment,
139                                          StringRef Section,
140                                          unsigned TypeAndAttributes,
141                                          SectionKind K) {
142      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
143    }
144
145    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
146                                      unsigned Flags, SectionKind Kind);
147
148    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
149                                      unsigned Flags, SectionKind Kind,
150                                      unsigned EntrySize, StringRef Group);
151
152    const MCSectionELF *CreateELFGroupSection();
153
154    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
155                                    int Selection, SectionKind Kind);
156
157    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
158                                    SectionKind Kind) {
159      return getCOFFSection (Section, Characteristics, 0, Kind);
160    }
161
162
163    /// @}
164
165    /// @name Dwarf Management
166    /// @{
167
168    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
169    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
170
171    bool isValidDwarfFileNumber(unsigned FileNumber);
172
173    bool hasDwarfFiles(void) {
174      return MCDwarfFiles.size() != 0;
175    }
176
177    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
178      return MCDwarfFiles;
179    }
180    const std::vector<StringRef> &getMCDwarfDirs() {
181      return MCDwarfDirs;
182    }
183
184    const DenseMap<const MCSection *, MCLineSection *>
185    &getMCLineSections() const {
186      return MCLineSections;
187    }
188    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
189      return MCLineSectionOrder;
190    }
191    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
192      MCLineSections[Sec] = Line;
193      MCLineSectionOrder.push_back(Sec);
194    }
195
196    /// setCurrentDwarfLoc - saves the information from the currently parsed
197    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
198    /// is assembled an entry in the line number table with this information and
199    /// the address of the instruction will be created.
200    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
201                            unsigned Flags, unsigned Isa,
202                            unsigned Discriminator) {
203      CurrentDwarfLoc.setFileNum(FileNum);
204      CurrentDwarfLoc.setLine(Line);
205      CurrentDwarfLoc.setColumn(Column);
206      CurrentDwarfLoc.setFlags(Flags);
207      CurrentDwarfLoc.setIsa(Isa);
208      CurrentDwarfLoc.setDiscriminator(Discriminator);
209      DwarfLocSeen = true;
210    }
211    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
212
213    bool getDwarfLocSeen() { return DwarfLocSeen; }
214    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
215
216    /// @}
217
218    char *getSecureLogFile() { return SecureLogFile; }
219    raw_ostream *getSecureLog() { return SecureLog; }
220    bool getSecureLogUsed() { return SecureLogUsed; }
221    void setSecureLog(raw_ostream *Value) {
222      SecureLog = Value;
223    }
224    void setSecureLogUsed(bool Value) {
225      SecureLogUsed = Value;
226    }
227
228    void *Allocate(unsigned Size, unsigned Align = 8) {
229      return Allocator.Allocate(Size, Align);
230    }
231    void Deallocate(void *Ptr) {
232    }
233  };
234
235} // end namespace llvm
236
237// operator new and delete aren't allowed inside namespaces.
238// The throw specifications are mandated by the standard.
239/// @brief Placement new for using the MCContext's allocator.
240///
241/// This placement form of operator new uses the MCContext's allocator for
242/// obtaining memory. It is a non-throwing new, which means that it returns
243/// null on error. (If that is what the allocator does. The current does, so if
244/// this ever changes, this operator will have to be changed, too.)
245/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
246/// @code
247/// // Default alignment (16)
248/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
249/// // Specific alignment
250/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
251/// @endcode
252/// Please note that you cannot use delete on the pointer; it must be
253/// deallocated using an explicit destructor call followed by
254/// @c Context.Deallocate(Ptr).
255///
256/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
257/// @param C The MCContext that provides the allocator.
258/// @param Alignment The alignment of the allocated memory (if the underlying
259///                  allocator supports it).
260/// @return The allocated memory. Could be NULL.
261inline void *operator new(size_t Bytes, llvm::MCContext &C,
262                          size_t Alignment = 16) throw () {
263  return C.Allocate(Bytes, Alignment);
264}
265/// @brief Placement delete companion to the new above.
266///
267/// This operator is just a companion to the new above. There is no way of
268/// invoking it directly; see the new operator for more details. This operator
269/// is called implicitly by the compiler if a placement new expression using
270/// the MCContext throws in the object constructor.
271inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
272              throw () {
273  C.Deallocate(Ptr);
274}
275
276/// This placement form of operator new[] uses the MCContext's allocator for
277/// obtaining memory. It is a non-throwing new[], which means that it returns
278/// null on error.
279/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
280/// @code
281/// // Default alignment (16)
282/// char *data = new (Context) char[10];
283/// // Specific alignment
284/// char *data = new (Context, 8) char[10];
285/// @endcode
286/// Please note that you cannot use delete on the pointer; it must be
287/// deallocated using an explicit destructor call followed by
288/// @c Context.Deallocate(Ptr).
289///
290/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
291/// @param C The MCContext that provides the allocator.
292/// @param Alignment The alignment of the allocated memory (if the underlying
293///                  allocator supports it).
294/// @return The allocated memory. Could be NULL.
295inline void *operator new[](size_t Bytes, llvm::MCContext& C,
296                            size_t Alignment = 16) throw () {
297  return C.Allocate(Bytes, Alignment);
298}
299
300/// @brief Placement delete[] companion to the new[] above.
301///
302/// This operator is just a companion to the new[] above. There is no way of
303/// invoking it directly; see the new[] operator for more details. This operator
304/// is called implicitly by the compiler if a placement new[] expression using
305/// the MCContext throws in the object constructor.
306inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
307  C.Deallocate(Ptr);
308}
309
310#endif
311