MCContext.h revision 0e6a052331f674dd70e28af41f654a7874405eab 
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 MCRegisterInfo;
30  class MCLineSection;
31  class StringRef;
32  class Twine;
33  class TargetAsmInfo;
34  class MCSectionMachO;
35  class MCSectionELF;
36
37  /// MCContext - Context object for machine code objects.  This class owns all
38  /// of the sections that it creates.
39  ///
40  class MCContext {
41    MCContext(const MCContext&); // DO NOT IMPLEMENT
42    MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
43  public:
44    typedef StringMap<MCSymbol*, BumpPtrAllocator&> SymbolTable;
45  private:
46
47    /// The MCAsmInfo for this target.
48    const MCAsmInfo &MAI;
49
50    /// The MCRegisterInfo for this target.
51    const MCRegisterInfo &MRI;
52
53    const TargetAsmInfo *TAI;
54
55    /// Allocator - Allocator object used for creating machine code objects.
56    ///
57    /// We use a bump pointer allocator to avoid the need to track all allocated
58    /// objects.
59    BumpPtrAllocator Allocator;
60
61    /// Symbols - Bindings of names to symbols.
62    SymbolTable Symbols;
63
64    /// UsedNames - Keeps tracks of names that were used both for used declared
65    /// and artificial symbols.
66    StringMap<bool, BumpPtrAllocator&> UsedNames;
67
68    /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
69    /// symbol.
70    unsigned NextUniqueID;
71
72    /// Instances of directional local labels.
73    DenseMap<unsigned, MCLabel *> Instances;
74    /// NextInstance() creates the next instance of the directional local label
75    /// for the LocalLabelVal and adds it to the map if needed.
76    unsigned NextInstance(int64_t LocalLabelVal);
77    /// GetInstance() gets the current instance of the directional local label
78    /// for the LocalLabelVal and adds it to the map if needed.
79    unsigned GetInstance(int64_t LocalLabelVal);
80
81    /// The file name of the log file from the environment variable
82    /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
83    /// directive is used or it is an error.
84    char *SecureLogFile;
85    /// The stream that gets written to for the .secure_log_unique directive.
86    raw_ostream *SecureLog;
87    /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
88    /// catch errors if .secure_log_unique appears twice without
89    /// .secure_log_reset appearing between them.
90    bool SecureLogUsed;
91
92    /// The dwarf file and directory tables from the dwarf .file directive.
93    std::vector<MCDwarfFile *> MCDwarfFiles;
94    std::vector<StringRef> MCDwarfDirs;
95
96    /// The current dwarf line information from the last dwarf .loc directive.
97    MCDwarfLoc CurrentDwarfLoc;
98    bool DwarfLocSeen;
99
100    /// Honor temporary labels, this is useful for debugging semantic
101    /// differences between temporary and non-temporary labels (primarily on
102    /// Darwin).
103    bool AllowTemporaryLabels;
104
105    /// The dwarf line information from the .loc directives for the sections
106    /// with assembled machine instructions have after seeing .loc directives.
107    DenseMap<const MCSection *, MCLineSection *> MCLineSections;
108    /// We need a deterministic iteration order, so we remember the order
109    /// the elements were added.
110    std::vector<const MCSection *> MCLineSectionOrder;
111
112    void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;
113
114    MCSymbol *CreateSymbol(StringRef Name);
115
116  public:
117    explicit MCContext(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
118                       const TargetAsmInfo *TAI);
119    ~MCContext();
120
121    const MCAsmInfo &getAsmInfo() const { return MAI; }
122
123    const MCRegisterInfo &getRegisterInfo() const { return MRI; }
124
125    const TargetAsmInfo &getTargetAsmInfo() const { return *TAI; }
126
127    void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
128
129    /// @name Symbol Management
130    /// @{
131
132    /// CreateTempSymbol - Create and return a new assembler temporary symbol
133    /// with a unique but unspecified name.
134    MCSymbol *CreateTempSymbol();
135
136    /// CreateDirectionalLocalSymbol - Create the definition of a directional
137    /// local symbol for numbered label (used for "1:" definitions).
138    MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);
139
140    /// GetDirectionalLocalSymbol - Create and return a directional local
141    /// symbol for numbered label (used for "1b" or 1f" references).
142    MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);
143
144    /// GetOrCreateSymbol - Lookup the symbol inside with the specified
145    /// @p Name.  If it exists, return it.  If not, create a forward
146    /// reference and return it.
147    ///
148    /// @param Name - The symbol name, which must be unique across all symbols.
149    MCSymbol *GetOrCreateSymbol(StringRef Name);
150    MCSymbol *GetOrCreateSymbol(const Twine &Name);
151
152    /// LookupSymbol - Get the symbol for \p Name, or null.
153    MCSymbol *LookupSymbol(StringRef Name) const;
154
155    /// getSymbols - Get a reference for the symbol table for clients that
156    /// want to, for example, iterate over all symbols. 'const' because we
157    /// still want any modifications to the table itself to use the MCContext
158    /// APIs.
159    const SymbolTable &getSymbols() const {
160      return Symbols;
161    }
162
163    /// @}
164
165    /// @name Section Management
166    /// @{
167
168    /// getMachOSection - Return the MCSection for the specified mach-o section.
169    /// This requires the operands to be valid.
170    const MCSectionMachO *getMachOSection(StringRef Segment,
171                                          StringRef Section,
172                                          unsigned TypeAndAttributes,
173                                          unsigned Reserved2,
174                                          SectionKind K);
175    const MCSectionMachO *getMachOSection(StringRef Segment,
176                                          StringRef Section,
177                                          unsigned TypeAndAttributes,
178                                          SectionKind K) {
179      return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
180    }
181
182    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
183                                      unsigned Flags, SectionKind Kind);
184
185    const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
186                                      unsigned Flags, SectionKind Kind,
187                                      unsigned EntrySize, StringRef Group);
188
189    const MCSectionELF *CreateELFGroupSection();
190
191    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
192                                    int Selection, SectionKind Kind);
193
194    const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
195                                    SectionKind Kind) {
196      return getCOFFSection (Section, Characteristics, 0, Kind);
197    }
198
199
200    /// @}
201
202    /// @name Dwarf Management
203    /// @{
204
205    /// GetDwarfFile - creates an entry in the dwarf file and directory tables.
206    unsigned GetDwarfFile(StringRef FileName, unsigned FileNumber);
207
208    bool isValidDwarfFileNumber(unsigned FileNumber);
209
210    bool hasDwarfFiles() const {
211      return !MCDwarfFiles.empty();
212    }
213
214    const std::vector<MCDwarfFile *> &getMCDwarfFiles() {
215      return MCDwarfFiles;
216    }
217    const std::vector<StringRef> &getMCDwarfDirs() {
218      return MCDwarfDirs;
219    }
220
221    const DenseMap<const MCSection *, MCLineSection *>
222    &getMCLineSections() const {
223      return MCLineSections;
224    }
225    const std::vector<const MCSection *> &getMCLineSectionOrder() const {
226      return MCLineSectionOrder;
227    }
228    void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
229      MCLineSections[Sec] = Line;
230      MCLineSectionOrder.push_back(Sec);
231    }
232
233    /// setCurrentDwarfLoc - saves the information from the currently parsed
234    /// dwarf .loc directive and sets DwarfLocSeen.  When the next instruction
235    /// is assembled an entry in the line number table with this information and
236    /// the address of the instruction will be created.
237    void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
238                            unsigned Flags, unsigned Isa,
239                            unsigned Discriminator) {
240      CurrentDwarfLoc.setFileNum(FileNum);
241      CurrentDwarfLoc.setLine(Line);
242      CurrentDwarfLoc.setColumn(Column);
243      CurrentDwarfLoc.setFlags(Flags);
244      CurrentDwarfLoc.setIsa(Isa);
245      CurrentDwarfLoc.setDiscriminator(Discriminator);
246      DwarfLocSeen = true;
247    }
248    void ClearDwarfLocSeen() { DwarfLocSeen = false; }
249
250    bool getDwarfLocSeen() { return DwarfLocSeen; }
251    const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }
252
253    /// @}
254
255    char *getSecureLogFile() { return SecureLogFile; }
256    raw_ostream *getSecureLog() { return SecureLog; }
257    bool getSecureLogUsed() { return SecureLogUsed; }
258    void setSecureLog(raw_ostream *Value) {
259      SecureLog = Value;
260    }
261    void setSecureLogUsed(bool Value) {
262      SecureLogUsed = Value;
263    }
264
265    void *Allocate(unsigned Size, unsigned Align = 8) {
266      return Allocator.Allocate(Size, Align);
267    }
268    void Deallocate(void *Ptr) {
269    }
270  };
271
272} // end namespace llvm
273
274// operator new and delete aren't allowed inside namespaces.
275// The throw specifications are mandated by the standard.
276/// @brief Placement new for using the MCContext's allocator.
277///
278/// This placement form of operator new uses the MCContext's allocator for
279/// obtaining memory. It is a non-throwing new, which means that it returns
280/// null on error. (If that is what the allocator does. The current does, so if
281/// this ever changes, this operator will have to be changed, too.)
282/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
283/// @code
284/// // Default alignment (16)
285/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
286/// // Specific alignment
287/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
288/// @endcode
289/// Please note that you cannot use delete on the pointer; it must be
290/// deallocated using an explicit destructor call followed by
291/// @c Context.Deallocate(Ptr).
292///
293/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
294/// @param C The MCContext that provides the allocator.
295/// @param Alignment The alignment of the allocated memory (if the underlying
296///                  allocator supports it).
297/// @return The allocated memory. Could be NULL.
298inline void *operator new(size_t Bytes, llvm::MCContext &C,
299                          size_t Alignment = 16) throw () {
300  return C.Allocate(Bytes, Alignment);
301}
302/// @brief Placement delete companion to the new above.
303///
304/// This operator is just a companion to the new above. There is no way of
305/// invoking it directly; see the new operator for more details. This operator
306/// is called implicitly by the compiler if a placement new expression using
307/// the MCContext throws in the object constructor.
308inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
309              throw () {
310  C.Deallocate(Ptr);
311}
312
313/// This placement form of operator new[] uses the MCContext's allocator for
314/// obtaining memory. It is a non-throwing new[], which means that it returns
315/// null on error.
316/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
317/// @code
318/// // Default alignment (16)
319/// char *data = new (Context) char[10];
320/// // Specific alignment
321/// char *data = new (Context, 8) char[10];
322/// @endcode
323/// Please note that you cannot use delete on the pointer; it must be
324/// deallocated using an explicit destructor call followed by
325/// @c Context.Deallocate(Ptr).
326///
327/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
328/// @param C The MCContext that provides the allocator.
329/// @param Alignment The alignment of the allocated memory (if the underlying
330///                  allocator supports it).
331/// @return The allocated memory. Could be NULL.
332inline void *operator new[](size_t Bytes, llvm::MCContext& C,
333                            size_t Alignment = 16) throw () {
334  return C.Allocate(Bytes, Alignment);
335}
336
337/// @brief Placement delete[] companion to the new[] above.
338///
339/// This operator is just a companion to the new[] above. There is no way of
340/// invoking it directly; see the new[] operator for more details. This operator
341/// is called implicitly by the compiler if a placement new[] expression using
342/// the MCContext throws in the object constructor.
343inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
344  C.Deallocate(Ptr);
345}
346
347#endif
348