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"
22 /// MCContext - Context object for machine code objects.
24 MCContext(const MCContext&); // DO NOT IMPLEMENT
25 MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
27 /// Sections - Bindings of names to allocated sections.
28 StringMap<MCSection*> Sections;
30 /// Symbols - Bindings of names to symbols.
31 StringMap<MCSymbol*> Symbols;
33 /// SymbolValues - Bindings of symbols to values.
34 DenseMap<MCSymbol*, MCValue> SymbolValues;
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;
46 /// GetSection - Get or create a new section with the given @param Name.
47 MCSection *GetSection(const char *Name);
49 /// CreateSymbol - Create a new symbol with the specified @param Name.
51 /// @param Name - The symbol name, which must be unique across all symbols.
52 MCSymbol *CreateSymbol(const char *Name);
54 /// GetOrCreateSymbol - Lookup the symbol inside with the specified
55 /// @param Name. If it exists, return it. If not, create a forward
56 /// reference and return it.
58 /// @param Name - The symbol name, which must be unique across all symbols.
59 MCSymbol *GetOrCreateSymbol(const char *Name);
61 /// CreateTemporarySymbol - Create a new temporary symbol with the specified
64 /// @param Name - The symbol name, for debugging purposes only, temporary
65 /// symbols do not surive assembly. If non-empty the name must be unique
66 /// across all symbols.
67 MCSymbol *CreateTemporarySymbol(const char *Name = "");
69 /// LookupSymbol - Get the symbol for @param Name, or null.
70 MCSymbol *LookupSymbol(const char *Name) const;
72 /// ClearSymbolValue - Erase a value binding for @param Symbol, if one
74 void ClearSymbolValue(MCSymbol *Symbol);
76 /// SetSymbolValue - Set the value binding for @param Symbol to @param
78 void SetSymbolValue(MCSymbol *Symbol, const MCValue &Value);
80 /// GetSymbolValue - Return the current value for @param Symbol, or null if
82 const MCValue *GetSymbolValue(MCSymbol *Symbol) const;
84 void *Allocate(unsigned Size, unsigned Align = 8) {
85 return Allocator.Allocate(Size, Align);
87 void Deallocate(void *Ptr) {
91 } // end namespace llvm
93 // operator new and delete aren't allowed inside namespaces.
94 // The throw specifications are mandated by the standard.
95 /// @brief Placement new for using the MCContext's allocator.
97 /// This placement form of operator new uses the MCContext's allocator for
98 /// obtaining memory. It is a non-throwing new, which means that it returns
99 /// null on error. (If that is what the allocator does. The current does, so if
100 /// this ever changes, this operator will have to be changed, too.)
101 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
103 /// // Default alignment (16)
104 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
105 /// // Specific alignment
106 /// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
108 /// Please note that you cannot use delete on the pointer; it must be
109 /// deallocated using an explicit destructor call followed by
110 /// @c Context.Deallocate(Ptr).
112 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
113 /// @param C The MCContext that provides the allocator.
114 /// @param Alignment The alignment of the allocated memory (if the underlying
115 /// allocator supports it).
116 /// @return The allocated memory. Could be NULL.
117 inline void *operator new(size_t Bytes, llvm::MCContext &C,
118 size_t Alignment = 16) throw () {
119 return C.Allocate(Bytes, Alignment);
121 /// @brief Placement delete companion to the new above.
123 /// This operator is just a companion to the new above. There is no way of
124 /// invoking it directly; see the new operator for more details. This operator
125 /// is called implicitly by the compiler if a placement new expression using
126 /// the MCContext throws in the object constructor.
127 inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
132 /// This placement form of operator new[] uses the MCContext's allocator for
133 /// obtaining memory. It is a non-throwing new[], which means that it returns
135 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
137 /// // Default alignment (16)
138 /// char *data = new (Context) char[10];
139 /// // Specific alignment
140 /// char *data = new (Context, 8) char[10];
142 /// Please note that you cannot use delete on the pointer; it must be
143 /// deallocated using an explicit destructor call followed by
144 /// @c Context.Deallocate(Ptr).
146 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
147 /// @param C The MCContext that provides the allocator.
148 /// @param Alignment The alignment of the allocated memory (if the underlying
149 /// allocator supports it).
150 /// @return The allocated memory. Could be NULL.
151 inline void *operator new[](size_t Bytes, llvm::MCContext& C,
152 size_t Alignment = 16) throw () {
153 return C.Allocate(Bytes, Alignment);
156 /// @brief Placement delete[] companion to the new[] above.
158 /// This operator is just a companion to the new[] above. There is no way of
159 /// invoking it directly; see the new[] operator for more details. This operator
160 /// is called implicitly by the compiler if a placement new[] expression using
161 /// the MCContext throws in the object constructor.
162 inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {