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"
23 /// MCContext - Context object for machine code objects. This class owns all
24 /// of the sections that it creates.
27 MCContext(const MCContext&); // DO NOT IMPLEMENT
28 MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
30 /// Sections - Bindings of names to allocated sections.
31 StringMap<MCSection*> Sections;
33 /// Symbols - Bindings of names to symbols.
34 StringMap<MCSymbol*> Symbols;
36 /// Allocator - Allocator object used for creating machine code objects.
38 /// We use a bump pointer allocator to avoid the need to track all allocated
40 BumpPtrAllocator Allocator;
45 /// @name Symbol Managment
48 /// CreateSymbol - Create a new symbol with the specified @param Name.
50 /// @param Name - The symbol name, which must be unique across all symbols.
51 MCSymbol *CreateSymbol(const StringRef &Name);
53 /// GetOrCreateSymbol - Lookup the symbol inside with the specified
54 /// @param Name. If it exists, return it. If not, create a forward
55 /// reference and return it.
57 /// @param Name - The symbol name, which must be unique across all symbols.
58 /// @param IsTemporary - Whether this symbol is an assembler temporary,
59 /// which should not survive into the symbol table for the translation unit.
60 MCSymbol *GetOrCreateSymbol(const StringRef &Name);
62 /// CreateTemporarySymbol - Create a new temporary symbol with the specified
65 /// @param Name - The symbol name, for debugging purposes only, temporary
66 /// symbols do not surive assembly. If non-empty the name must be unique
67 /// across all symbols.
68 MCSymbol *CreateTemporarySymbol(const StringRef &Name = "");
70 /// LookupSymbol - Get the symbol for @param Name, or null.
71 MCSymbol *LookupSymbol(const StringRef &Name) const;
75 void *Allocate(unsigned Size, unsigned Align = 8) {
76 return Allocator.Allocate(Size, Align);
78 void Deallocate(void *Ptr) {
82 } // end namespace llvm
84 // operator new and delete aren't allowed inside namespaces.
85 // The throw specifications are mandated by the standard.
86 /// @brief Placement new for using the MCContext's allocator.
88 /// This placement form of operator new uses the MCContext's allocator for
89 /// obtaining memory. It is a non-throwing new, which means that it returns
90 /// null on error. (If that is what the allocator does. The current does, so if
91 /// this ever changes, this operator will have to be changed, too.)
92 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
94 /// // Default alignment (16)
95 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
96 /// // Specific alignment
97 /// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
99 /// Please note that you cannot use delete on the pointer; it must be
100 /// deallocated using an explicit destructor call followed by
101 /// @c Context.Deallocate(Ptr).
103 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
104 /// @param C The MCContext that provides the allocator.
105 /// @param Alignment The alignment of the allocated memory (if the underlying
106 /// allocator supports it).
107 /// @return The allocated memory. Could be NULL.
108 inline void *operator new(size_t Bytes, llvm::MCContext &C,
109 size_t Alignment = 16) throw () {
110 return C.Allocate(Bytes, Alignment);
112 /// @brief Placement delete companion to the new above.
114 /// This operator is just a companion to the new above. There is no way of
115 /// invoking it directly; see the new operator for more details. This operator
116 /// is called implicitly by the compiler if a placement new expression using
117 /// the MCContext throws in the object constructor.
118 inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
123 /// This placement form of operator new[] uses the MCContext's allocator for
124 /// obtaining memory. It is a non-throwing new[], which means that it returns
126 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
128 /// // Default alignment (16)
129 /// char *data = new (Context) char[10];
130 /// // Specific alignment
131 /// char *data = new (Context, 8) char[10];
133 /// Please note that you cannot use delete on the pointer; it must be
134 /// deallocated using an explicit destructor call followed by
135 /// @c Context.Deallocate(Ptr).
137 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
138 /// @param C The MCContext that provides the allocator.
139 /// @param Alignment The alignment of the allocated memory (if the underlying
140 /// allocator supports it).
141 /// @return The allocated memory. Could be NULL.
142 inline void *operator new[](size_t Bytes, llvm::MCContext& C,
143 size_t Alignment = 16) throw () {
144 return C.Allocate(Bytes, Alignment);
147 /// @brief Placement delete[] companion to the new[] above.
149 /// This operator is just a companion to the new[] above. There is no way of
150 /// invoking it directly; see the new[] operator for more details. This operator
151 /// is called implicitly by the compiler if a placement new[] expression using
152 /// the MCContext throws in the object constructor.
153 inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {