MCContext.h revision 89b9372605db2ce3b0085c84089e389f7bc1fbdd 
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
43    /// The MCAsmInfo for this target.
44    const MCAsmInfo &MAI;
45
46    const TargetAsmInfo *TAI;
47
48    /// Symbols - Bindings of names to symbols.
49    StringMap<MCSymbol*> Symbols;
50
51    /// UsedNames - Keeps tracks of names that were used both for used declared
52    /// and artificial symbols.
53    StringMap<bool> UsedNames;
54
55    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
56    /// symbol.
57    unsigned NextUniqueID;
58
59    /// Instances of directional local labels.
60    DenseMap<unsigned, MCLabel *> Instances;
61    /// NextInstance() creates the next instance of the directional local label
62    /// for the LocalLabelVal and adds it to the map if needed.
63    unsigned NextInstance(int64_t LocalLabelVal);
64    /// GetInstance() gets the current instance of the directional local label
65    /// for the LocalLabelVal and adds it to the map if needed.
66    unsigned GetInstance(int64_t LocalLabelVal);
67
68    /// The file name of the log file from the environment variable
69    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
70    /// directive is used or it is an error.
71    char *SecureLogFile;
72    /// The stream that gets written to for the .secure_log_unique directive.
73    raw_ostream *SecureLog;
74    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
75    /// catch errors if .secure_log_unique appears twice without
76    /// .secure_log_reset appearing between them.
77    bool SecureLogUsed;
78
79    /// The dwarf file and directory tables from the dwarf .file directive.
80    std::vector<MCDwarfFile *> MCDwarfFiles;
81    std::vector<StringRef> MCDwarfDirs;
82
83    /// The current dwarf line information from the last dwarf .loc directive.
84    MCDwarfLoc CurrentDwarfLoc;
85    bool DwarfLocSeen;
86
87    /// The dwarf line information from the .loc directives for the sections
88    /// with assembled machine instructions have after seeing .loc directives.
89    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
90    /// We need a deterministic iteration order, so we remember the order
91    /// the elements were added.
92    std::vector<const MCSection *> MCLineSectionOrder;
93
94    /// Allocator - Allocator object used for creating machine code objects.
95    ///
96    /// We use a bump pointer allocator to avoid the need to track all allocated
97    /// objects.
98    BumpPtrAllocator Allocator;
99
100    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
101
102    MCSymbol *CreateSymbol(StringRef Name);
103
104  public:
105    explicit MCContext(const MCAsmInfo &MAI, const TargetAsmInfo *TAI);
106    ~MCContext();
107
108    const MCAsmInfo &getAsmInfo() const { return MAI; }
109
110    const TargetAsmInfo &getTargetAsmInfo() const { return *TAI; }
111
112    /// @name Symbol Management
113    /// @{
114
115    /// CreateTempSymbol - Create and return a new assembler temporary symbol
116    /// with a unique but unspecified name.
117    MCSymbol *CreateTempSymbol();
118
119    /// CreateDirectionalLocalSymbol - Create the definition of a directional
120    /// local symbol for numbered label (used for "1:" definitions).
121    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
122
123    /// GetDirectionalLocalSymbol - Create and return a directional local
124    /// symbol for numbered label (used for "1b" or 1f" references).
125    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
126
127    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
128    /// @p Name.  If it exists, return it.  If not, create a forward
129    /// reference and return it.
130    ///
131    /// @param Name - The symbol name, which must be unique across all symbols.
132    MCSymbol *GetOrCreateSymbol(StringRef Name);
133    MCSymbol *GetOrCreateSymbol(const Twine &Name);
134
135    /// LookupSymbol - Get the symbol for \p Name, or null.
136    MCSymbol *LookupSymbol(StringRef Name) const;
137
138    /// @}
139
140    /// @name Section Management
141    /// @{
142
143    /// getMachOSection - Return the MCSection for the specified mach-o section.
144    /// This requires the operands to be valid.
145    const MCSectionMachO *getMachOSection(StringRef Segment,
146                                          StringRef Section,
147                                          unsigned TypeAndAttributes,
148                                          unsigned Reserved2,
149                                          SectionKind K);
150    const MCSectionMachO *getMachOSection(StringRef Segment,
151                                          StringRef Section,
152                                          unsigned TypeAndAttributes,
153                                          SectionKind K) {
154      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
155    }
156
157    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
158                                      unsigned Flags, SectionKind Kind);
159
160    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
161                                      unsigned Flags, SectionKind Kind,
162                                      unsigned EntrySize, StringRef Group);
163
164    const MCSectionELF *CreateELFGroupSection();
165
166    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
167                                    int Selection, SectionKind Kind);
168
169    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
170                                    SectionKind Kind) {
171      return getCOFFSection (Section, Characteristics, 0, Kind);
172    }
173
174
175    /// @}
176
177    /// @name Dwarf Management
178    /// @{
179
180    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
181    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
182
183    bool isValidDwarfFileNumber(unsigned FileNumber);
184
185    bool hasDwarfFiles() const {
186      return !MCDwarfFiles.empty();
187    }
188
189    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
190      return MCDwarfFiles;
191    }
192    const std::vector<StringRef> &getMCDwarfDirs() {
193      return MCDwarfDirs;
194    }
195
196    const DenseMap<const MCSection *, MCLineSection *>
197    &getMCLineSections() const {
198      return MCLineSections;
199    }
200    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
201      return MCLineSectionOrder;
202    }
203    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
204      MCLineSections[Sec] = Line;
205      MCLineSectionOrder.push_back(Sec);
206    }
207
208    /// setCurrentDwarfLoc - saves the information from the currently parsed
209    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
210    /// is assembled an entry in the line number table with this information and
211    /// the address of the instruction will be created.
212    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
213                            unsigned Flags, unsigned Isa,
214                            unsigned Discriminator) {
215      CurrentDwarfLoc.setFileNum(FileNum);
216      CurrentDwarfLoc.setLine(Line);
217      CurrentDwarfLoc.setColumn(Column);
218      CurrentDwarfLoc.setFlags(Flags);
219      CurrentDwarfLoc.setIsa(Isa);
220      CurrentDwarfLoc.setDiscriminator(Discriminator);
221      DwarfLocSeen = true;
222    }
223    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
224
225    bool getDwarfLocSeen() { return DwarfLocSeen; }
226    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
227
228    /// @}
229
230    char *getSecureLogFile() { return SecureLogFile; }
231    raw_ostream *getSecureLog() { return SecureLog; }
232    bool getSecureLogUsed() { return SecureLogUsed; }
233    void setSecureLog(raw_ostream *Value) {
234      SecureLog = Value;
235    }
236    void setSecureLogUsed(bool Value) {
237      SecureLogUsed = Value;
238    }
239
240    void *Allocate(unsigned Size, unsigned Align = 8) {
241      return Allocator.Allocate(Size, Align);
242    }
243    void Deallocate(void *Ptr) {
244    }
245  };
246
247} // end namespace llvm
248
249// operator new and delete aren't allowed inside namespaces.
250// The throw specifications are mandated by the standard.
251/// @brief Placement new for using the MCContext's allocator.
252///
253/// This placement form of operator new uses the MCContext's allocator for
254/// obtaining memory. It is a non-throwing new, which means that it returns
255/// null on error. (If that is what the allocator does. The current does, so if
256/// this ever changes, this operator will have to be changed, too.)
257/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
258/// @code
259/// // Default alignment (16)
260/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
261/// // Specific alignment
262/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
263/// @endcode
264/// Please note that you cannot use delete on the pointer; it must be
265/// deallocated using an explicit destructor call followed by
266/// @c Context.Deallocate(Ptr).
267///
268/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
269/// @param C The MCContext that provides the allocator.
270/// @param Alignment The alignment of the allocated memory (if the underlying
271///                  allocator supports it).
272/// @return The allocated memory. Could be NULL.
273inline void *operator new(size_t Bytes, llvm::MCContext &C,
274                          size_t Alignment = 16) throw () {
275  return C.Allocate(Bytes, Alignment);
276}
277/// @brief Placement delete companion to the new above.
278///
279/// This operator is just a companion to the new above. There is no way of
280/// invoking it directly; see the new operator for more details. This operator
281/// is called implicitly by the compiler if a placement new expression using
282/// the MCContext throws in the object constructor.
283inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
284              throw () {
285  C.Deallocate(Ptr);
286}
287
288/// This placement form of operator new[] uses the MCContext's allocator for
289/// obtaining memory. It is a non-throwing new[], which means that it returns
290/// null on error.
291/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
292/// @code
293/// // Default alignment (16)
294/// char *data = new (Context) char[10];
295/// // Specific alignment
296/// char *data = new (Context, 8) char[10];
297/// @endcode
298/// Please note that you cannot use delete on the pointer; it must be
299/// deallocated using an explicit destructor call followed by
300/// @c Context.Deallocate(Ptr).
301///
302/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
303/// @param C The MCContext that provides the allocator.
304/// @param Alignment The alignment of the allocated memory (if the underlying
305///                  allocator supports it).
306/// @return The allocated memory. Could be NULL.
307inline void *operator new[](size_t Bytes, llvm::MCContext& C,
308                            size_t Alignment = 16) throw () {
309  return C.Allocate(Bytes, Alignment);
310}
311
312/// @brief Placement delete[] companion to the new[] above.
313///
314/// This operator is just a companion to the new[] above. There is no way of
315/// invoking it directly; see the new[] operator for more details. This operator
316/// is called implicitly by the compiler if a placement new[] expression using
317/// the MCContext throws in the object constructor.
318inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
319  C.Deallocate(Ptr);
320}
321
322#endif
323