MCContext.h revision 4283f4b81e8c1cbf5c7a7b51e949e109ae25ff8c 
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 enviromment 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
84    /// Allocator - Allocator object used for creating machine code objects.
85    ///
86    /// We use a bump pointer allocator to avoid the need to track all allocated
87    /// objects.
88    BumpPtrAllocator Allocator;
89
90    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
91  public:
92    explicit MCContext(const MCAsmInfo &MAI);
93    ~MCContext();
94
95    const MCAsmInfo &getAsmInfo() const { return MAI; }
96
97    /// @name Symbol Managment
98    /// @{
99
100    /// CreateTempSymbol - Create and return a new assembler temporary symbol
101    /// with a unique but unspecified name.
102    MCSymbol *CreateTempSymbol();
103
104    /// CreateDirectionalLocalSymbol - Create the defintion of a directional
105    /// local symbol for numbered label (used for "1:" defintions).
106    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
107
108    /// GetDirectionalLocalSymbol - Create and return a directional local
109    /// symbol for numbered label (used for "1b" or 1f" references).
110    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
111
112    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
113    /// @p Name.  If it exists, return it.  If not, create a forward
114    /// reference and return it.
115    ///
116    /// @param Name - The symbol name, which must be unique across all symbols.
117    MCSymbol *GetOrCreateSymbol(StringRef Name);
118    MCSymbol *GetOrCreateSymbol(const Twine &Name);
119
120    /// LookupSymbol - Get the symbol for \p Name, or null.
121    MCSymbol *LookupSymbol(StringRef Name) const;
122
123    /// @}
124
125    /// @name Section Managment
126    /// @{
127
128    /// getMachOSection - Return the MCSection for the specified mach-o section.
129    /// This requires the operands to be valid.
130    const MCSectionMachO *getMachOSection(StringRef Segment,
131                                          StringRef Section,
132                                          unsigned TypeAndAttributes,
133                                          unsigned Reserved2,
134                                          SectionKind K);
135    const MCSectionMachO *getMachOSection(StringRef Segment,
136                                          StringRef Section,
137                                          unsigned TypeAndAttributes,
138                                          SectionKind K) {
139      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
140    }
141
142    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
143                                      unsigned Flags, SectionKind Kind,
144                                      unsigned EntrySize = 0);
145
146    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
147                                    int Selection, SectionKind Kind);
148
149    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
150                                    SectionKind Kind) {
151      return getCOFFSection (Section, Characteristics, 0, Kind);
152    }
153
154
155    /// @}
156
157    /// @name Dwarf Managment
158    /// @{
159
160    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
161    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
162
163    bool isValidDwarfFileNumber(unsigned FileNumber);
164
165    bool hasDwarfFiles(void) {
166      return MCDwarfFiles.size() != 0;
167    }
168
169    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
170      return MCDwarfFiles;
171    }
172    const std::vector<StringRef> &getMCDwarfDirs() {
173      return MCDwarfDirs;
174    }
175    DenseMap<const MCSection *, MCLineSection *> &getMCLineSections() {
176      return MCLineSections;
177    }
178
179    /// setCurrentDwarfLoc - saves the information from the currently parsed
180    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
181    /// is assembled an entry in the line number table with this information and
182    /// the address of the instruction will be created.
183    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
184                            unsigned Flags, unsigned Isa) {
185      CurrentDwarfLoc.setFileNum(FileNum);
186      CurrentDwarfLoc.setLine(Line);
187      CurrentDwarfLoc.setColumn(Column);
188      CurrentDwarfLoc.setFlags(Flags);
189      CurrentDwarfLoc.setIsa(Isa);
190      DwarfLocSeen = true;
191    }
192    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
193
194    bool getDwarfLocSeen() { return DwarfLocSeen; }
195    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
196
197    /// @}
198
199    char *getSecureLogFile() { return SecureLogFile; }
200    raw_ostream *getSecureLog() { return SecureLog; }
201    bool getSecureLogUsed() { return SecureLogUsed; }
202    void setSecureLog(raw_ostream *Value) {
203      SecureLog = Value;
204    }
205    void setSecureLogUsed(bool Value) {
206      SecureLogUsed = Value;
207    }
208
209    void *Allocate(unsigned Size, unsigned Align = 8) {
210      return Allocator.Allocate(Size, Align);
211    }
212    void Deallocate(void *Ptr) {
213    }
214  };
215
216} // end namespace llvm
217
218// operator new and delete aren't allowed inside namespaces.
219// The throw specifications are mandated by the standard.
220/// @brief Placement new for using the MCContext's allocator.
221///
222/// This placement form of operator new uses the MCContext's allocator for
223/// obtaining memory. It is a non-throwing new, which means that it returns
224/// null on error. (If that is what the allocator does. The current does, so if
225/// this ever changes, this operator will have to be changed, too.)
226/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
227/// @code
228/// // Default alignment (16)
229/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
230/// // Specific alignment
231/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
232/// @endcode
233/// Please note that you cannot use delete on the pointer; it must be
234/// deallocated using an explicit destructor call followed by
235/// @c Context.Deallocate(Ptr).
236///
237/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
238/// @param C The MCContext that provides the allocator.
239/// @param Alignment The alignment of the allocated memory (if the underlying
240///                  allocator supports it).
241/// @return The allocated memory. Could be NULL.
242inline void *operator new(size_t Bytes, llvm::MCContext &C,
243                          size_t Alignment = 16) throw () {
244  return C.Allocate(Bytes, Alignment);
245}
246/// @brief Placement delete companion to the new above.
247///
248/// This operator is just a companion to the new above. There is no way of
249/// invoking it directly; see the new operator for more details. This operator
250/// is called implicitly by the compiler if a placement new expression using
251/// the MCContext throws in the object constructor.
252inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
253              throw () {
254  C.Deallocate(Ptr);
255}
256
257/// This placement form of operator new[] uses the MCContext's allocator for
258/// obtaining memory. It is a non-throwing new[], which means that it returns
259/// null on error.
260/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
261/// @code
262/// // Default alignment (16)
263/// char *data = new (Context) char[10];
264/// // Specific alignment
265/// char *data = new (Context, 8) char[10];
266/// @endcode
267/// Please note that you cannot use delete on the pointer; it must be
268/// deallocated using an explicit destructor call followed by
269/// @c Context.Deallocate(Ptr).
270///
271/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
272/// @param C The MCContext that provides the allocator.
273/// @param Alignment The alignment of the allocated memory (if the underlying
274///                  allocator supports it).
275/// @return The allocated memory. Could be NULL.
276inline void *operator new[](size_t Bytes, llvm::MCContext& C,
277                            size_t Alignment = 16) throw () {
278  return C.Allocate(Bytes, Alignment);
279}
280
281/// @brief Placement delete[] companion to the new[] above.
282///
283/// This operator is just a companion to the new[] above. There is no way of
284/// invoking it directly; see the new[] operator for more details. This operator
285/// is called implicitly by the compiler if a placement new[] expression using
286/// the MCContext throws in the object constructor.
287inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
288  C.Deallocate(Ptr);
289}
290
291#endif
292