MCContext.h revision b07ce60981368f816af4caa3257e1e4ebf059133 
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/ADT/DenseMap.h"
15#include "llvm/ADT/StringMap.h"
16#include "llvm/Support/Allocator.h"
17#include "llvm/Support/raw_ostream.h"
18#include <vector> // FIXME: Shouldn't be needed.
19
20namespace llvm {
21  class MCAsmInfo;
22  class MCExpr;
23  class MCSection;
24  class MCSymbol;
25  class MCLabel;
26  class MCDwarfFile;
27  class StringRef;
28  class Twine;
29  class MCSectionMachO;
30
31  /// MCContext - Context object for machine code objects.  This class owns all
32  /// of the sections that it creates.
33  ///
34  class MCContext {
35    MCContext(const MCContext&); // DO NOT IMPLEMENT
36    MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
37
38    /// The MCAsmInfo for this target.
39    const MCAsmInfo &MAI;
40
41    /// Symbols - Bindings of names to symbols.
42    StringMap<MCSymbol*> Symbols;
43
44    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
45    /// symbol.
46    unsigned NextUniqueID;
47
48    /// Instances of directional local labels.
49    DenseMap<unsigned, MCLabel *> Instances;
50    /// NextInstance() creates the next instance of the directional local label
51    /// for the LocalLabelVal and adds it to the map if needed.
52    unsigned NextInstance(int64_t LocalLabelVal);
53    /// GetInstance() gets the current instance of the directional local label
54    /// for the LocalLabelVal and adds it to the map if needed.
55    unsigned GetInstance(int64_t LocalLabelVal);
56
57    /// The file name of the log file from the enviromment variable
58    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
59    /// directive is used or it is an error.
60    char *SecureLogFile;
61    /// The stream that gets written to for the .secure_log_unique directive.
62    raw_ostream *SecureLog;
63    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
64    /// catch errors if .secure_log_unique appears twice without
65    /// .secure_log_reset appearing between them.
66    bool SecureLogUsed;
67
68    /// The dwarf file and directory tables from the dwarf .file directive.
69    std::vector<MCDwarfFile *> MCDwarfFiles;
70    std::vector<StringRef> MCDwarfDirs;
71
72    /// Allocator - Allocator object used for creating machine code objects.
73    ///
74    /// We use a bump pointer allocator to avoid the need to track all allocated
75    /// objects.
76    BumpPtrAllocator Allocator;
77
78    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
79  public:
80    explicit MCContext(const MCAsmInfo &MAI);
81    ~MCContext();
82
83    const MCAsmInfo &getAsmInfo() const { return MAI; }
84
85    /// @name Symbol Managment
86    /// @{
87
88    /// CreateTempSymbol - Create and return a new assembler temporary symbol
89    /// with a unique but unspecified name.
90    MCSymbol *CreateTempSymbol();
91
92    /// CreateDirectionalLocalSymbol - Create the defintion of a directional
93    /// local symbol for numbered label (used for "1:" defintions).
94    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
95
96    /// GetDirectionalLocalSymbol - Create and return a directional local
97    /// symbol for numbered label (used for "1b" or 1f" references).
98    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
99
100    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
101    /// @p Name.  If it exists, return it.  If not, create a forward
102    /// reference and return it.
103    ///
104    /// @param Name - The symbol name, which must be unique across all symbols.
105    MCSymbol *GetOrCreateSymbol(StringRef Name);
106    MCSymbol *GetOrCreateSymbol(const Twine &Name);
107
108    /// LookupSymbol - Get the symbol for \p Name, or null.
109    MCSymbol *LookupSymbol(StringRef Name) const;
110
111    /// @}
112
113    /// @name Section Managment
114    /// @{
115
116    /// getMachOSection - Return the MCSection for the specified mach-o section.
117    /// This requires the operands to be valid.
118    const MCSectionMachO *getMachOSection(StringRef Segment,
119                                          StringRef Section,
120                                          unsigned TypeAndAttributes,
121                                          unsigned Reserved2,
122                                          SectionKind K);
123    const MCSectionMachO *getMachOSection(StringRef Segment,
124                                          StringRef Section,
125                                          unsigned TypeAndAttributes,
126                                          SectionKind K) {
127      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
128    }
129
130    const MCSection *getELFSection(StringRef Section, unsigned Type,
131                                   unsigned Flags, SectionKind Kind,
132                                   bool IsExplicit = false);
133
134    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
135                                    int Selection, SectionKind Kind);
136
137    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
138                                    SectionKind Kind) {
139      return getCOFFSection (Section, Characteristics, 0, Kind);
140    }
141
142
143    /// @}
144
145    /// @name Dwarf Managment
146    /// @{
147
148    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
149    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
150
151    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
152      return MCDwarfFiles;
153    }
154    const std::vector<StringRef> &getMCDwarfDirs() {
155      return MCDwarfDirs;
156    }
157
158    /// @}
159
160    char *getSecureLogFile() { return SecureLogFile; }
161    raw_ostream *getSecureLog() { return SecureLog; }
162    bool getSecureLogUsed() { return SecureLogUsed; }
163    void setSecureLog(raw_ostream *Value) {
164      SecureLog = Value;
165    }
166    void setSecureLogUsed(bool Value) {
167      SecureLogUsed = Value;
168    }
169
170    void *Allocate(unsigned Size, unsigned Align = 8) {
171      return Allocator.Allocate(Size, Align);
172    }
173    void Deallocate(void *Ptr) {
174    }
175  };
176
177} // end namespace llvm
178
179// operator new and delete aren't allowed inside namespaces.
180// The throw specifications are mandated by the standard.
181/// @brief Placement new for using the MCContext's allocator.
182///
183/// This placement form of operator new uses the MCContext's allocator for
184/// obtaining memory. It is a non-throwing new, which means that it returns
185/// null on error. (If that is what the allocator does. The current does, so if
186/// this ever changes, this operator will have to be changed, too.)
187/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
188/// @code
189/// // Default alignment (16)
190/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
191/// // Specific alignment
192/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
193/// @endcode
194/// Please note that you cannot use delete on the pointer; it must be
195/// deallocated using an explicit destructor call followed by
196/// @c Context.Deallocate(Ptr).
197///
198/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
199/// @param C The MCContext that provides the allocator.
200/// @param Alignment The alignment of the allocated memory (if the underlying
201///                  allocator supports it).
202/// @return The allocated memory. Could be NULL.
203inline void *operator new(size_t Bytes, llvm::MCContext &C,
204                          size_t Alignment = 16) throw () {
205  return C.Allocate(Bytes, Alignment);
206}
207/// @brief Placement delete companion to the new above.
208///
209/// This operator is just a companion to the new above. There is no way of
210/// invoking it directly; see the new operator for more details. This operator
211/// is called implicitly by the compiler if a placement new expression using
212/// the MCContext throws in the object constructor.
213inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
214              throw () {
215  C.Deallocate(Ptr);
216}
217
218/// This placement form of operator new[] uses the MCContext's allocator for
219/// obtaining memory. It is a non-throwing new[], which means that it returns
220/// null on error.
221/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
222/// @code
223/// // Default alignment (16)
224/// char *data = new (Context) char[10];
225/// // Specific alignment
226/// char *data = new (Context, 8) char[10];
227/// @endcode
228/// Please note that you cannot use delete on the pointer; it must be
229/// deallocated using an explicit destructor call followed by
230/// @c Context.Deallocate(Ptr).
231///
232/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
233/// @param C The MCContext that provides the allocator.
234/// @param Alignment The alignment of the allocated memory (if the underlying
235///                  allocator supports it).
236/// @return The allocated memory. Could be NULL.
237inline void *operator new[](size_t Bytes, llvm::MCContext& C,
238                            size_t Alignment = 16) throw () {
239  return C.Allocate(Bytes, Alignment);
240}
241
242/// @brief Placement delete[] companion to the new[] above.
243///
244/// This operator is just a companion to the new[] above. There is no way of
245/// invoking it directly; see the new[] operator for more details. This operator
246/// is called implicitly by the compiler if a placement new[] expression using
247/// the MCContext throws in the object constructor.
248inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
249  C.Deallocate(Ptr);
250}
251
252#endif
253