1 //===- MCContext.h - Machine Code Context -----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_MC_MCCONTEXT_H
11 #define LLVM_MC_MCCONTEXT_H
13 #include "llvm/ADT/DenseMap.h"
14 #include "llvm/ADT/StringMap.h"
15 #include "llvm/Support/Allocator.h"
25 /// MCContext - Context object for machine code objects. This class owns all
26 /// of the sections that it creates.
29 MCContext(const MCContext&); // DO NOT IMPLEMENT
30 MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
32 /// The MCAsmInfo for this target.
35 /// Sections - Bindings of names to allocated sections.
36 StringMap<MCSection*> Sections;
38 /// Symbols - Bindings of names to symbols.
39 StringMap<MCSymbol*> Symbols;
41 /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
43 unsigned NextUniqueID;
45 /// Allocator - Allocator object used for creating machine code objects.
47 /// We use a bump pointer allocator to avoid the need to track all allocated
49 BumpPtrAllocator Allocator;
51 explicit MCContext(const MCAsmInfo &MAI);
54 const MCAsmInfo &getAsmInfo() const { return MAI; }
56 /// @name Symbol Managment
59 /// CreateTempSymbol - Create and return a new assembler temporary symbol
60 /// with a unique but unspecified name.
61 MCSymbol *CreateTempSymbol();
63 /// GetOrCreateSymbol - Lookup the symbol inside with the specified
64 /// @p Name. If it exists, return it. If not, create a forward
65 /// reference and return it.
67 /// @param Name - The symbol name, which must be unique across all symbols.
68 MCSymbol *GetOrCreateSymbol(StringRef Name, bool isTemporary = false);
69 MCSymbol *GetOrCreateSymbol(const Twine &Name, bool isTemporary = false);
71 /// GetOrCreateTemporarySymbol - Create a new assembler temporary symbol
72 /// with the specified @p Name if it doesn't exist or return the existing
75 /// @param Name - The symbol name, for debugging purposes only, temporary
76 /// symbols do not surive assembly. If non-empty the name must be unique
77 /// across all symbols.
78 MCSymbol *GetOrCreateTemporarySymbol(StringRef Name = "");
79 MCSymbol *GetOrCreateTemporarySymbol(const Twine &Name);
81 /// LookupSymbol - Get the symbol for \p Name, or null.
82 MCSymbol *LookupSymbol(StringRef Name) const;
86 void *Allocate(unsigned Size, unsigned Align = 8) {
87 return Allocator.Allocate(Size, Align);
89 void Deallocate(void *Ptr) {
93 } // end namespace llvm
95 // operator new and delete aren't allowed inside namespaces.
96 // The throw specifications are mandated by the standard.
97 /// @brief Placement new for using the MCContext's allocator.
99 /// This placement form of operator new uses the MCContext's allocator for
100 /// obtaining memory. It is a non-throwing new, which means that it returns
101 /// null on error. (If that is what the allocator does. The current does, so if
102 /// this ever changes, this operator will have to be changed, too.)
103 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
105 /// // Default alignment (16)
106 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
107 /// // Specific alignment
108 /// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
110 /// Please note that you cannot use delete on the pointer; it must be
111 /// deallocated using an explicit destructor call followed by
112 /// @c Context.Deallocate(Ptr).
114 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
115 /// @param C The MCContext that provides the allocator.
116 /// @param Alignment The alignment of the allocated memory (if the underlying
117 /// allocator supports it).
118 /// @return The allocated memory. Could be NULL.
119 inline void *operator new(size_t Bytes, llvm::MCContext &C,
120 size_t Alignment = 16) throw () {
121 return C.Allocate(Bytes, Alignment);
123 /// @brief Placement delete companion to the new above.
125 /// This operator is just a companion to the new above. There is no way of
126 /// invoking it directly; see the new operator for more details. This operator
127 /// is called implicitly by the compiler if a placement new expression using
128 /// the MCContext throws in the object constructor.
129 inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
134 /// This placement form of operator new[] uses the MCContext's allocator for
135 /// obtaining memory. It is a non-throwing new[], which means that it returns
137 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
139 /// // Default alignment (16)
140 /// char *data = new (Context) char[10];
141 /// // Specific alignment
142 /// char *data = new (Context, 8) char[10];
144 /// Please note that you cannot use delete on the pointer; it must be
145 /// deallocated using an explicit destructor call followed by
146 /// @c Context.Deallocate(Ptr).
148 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
149 /// @param C The MCContext that provides the allocator.
150 /// @param Alignment The alignment of the allocated memory (if the underlying
151 /// allocator supports it).
152 /// @return The allocated memory. Could be NULL.
153 inline void *operator new[](size_t Bytes, llvm::MCContext& C,
154 size_t Alignment = 16) throw () {
155 return C.Allocate(Bytes, Alignment);
158 /// @brief Placement delete[] companion to the new[] above.
160 /// This operator is just a companion to the new[] above. There is no way of
161 /// invoking it directly; see the new[] operator for more details. This operator
162 /// is called implicitly by the compiler if a placement new[] expression using
163 /// the MCContext throws in the object constructor.
164 inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {