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.
25 MCContext(const MCContext&); // DO NOT IMPLEMENT
26 MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
28 /// Sections - Bindings of names to allocated sections.
29 StringMap<MCSection*> Sections;
31 /// Symbols - Bindings of names to symbols.
32 StringMap<MCSymbol*> Symbols;
34 /// SymbolValues - Bindings of symbols to values.
35 DenseMap<MCSymbol*, MCImm> SymbolValues;
37 /// Allocator - Allocator object used for creating machine code objects.
39 /// We use a bump pointer allocator to avoid the need to track all allocated
41 BumpPtrAllocator Allocator;
47 /// GetSection - Get or create a new section with the given @param Name.
48 MCSection *GetSection(const char *Name);
50 /// CreateAtom - Create a new atom inside @param Section.
51 MCAtom *CreateAtom(MCSection *Section);
53 /// CreateSymbol - Create a new symbol inside @param Atom with the specified
56 /// @param Name - The symbol name, which must be unique across all symbols.
57 MCSymbol *CreateSymbol(MCAtom *Atom, const char *Name);
59 /// CreateTemporarySymbol - Create a new temporary symbol inside @param Atom
60 /// with the specified @param Name.
62 /// @param Name - The symbol name, for debugging purposes only, temporary
63 /// symbols do not surive assembly. If non-empty the name must be unique
64 /// across all symbols.
65 MCSymbol *CreateTemporarySymbol(MCAtom *Atom, const char *Name = "");
67 /// LookupSymbol - Get the symbol for @param Name, or null.
68 MCSymbol *LookupSymbol(const char *Name) const;
70 /// ClearSymbolValue - Erase a value binding for @param Symbol, if one
72 void ClearSymbolValue(MCSymbol *Symbol);
74 /// SetSymbolValue - Set the value binding for @param Symbol to @param
76 void SetSymbolValue(MCSymbol *Symbol, const MCImm &Value);
78 /// GetSymbolValue - Return the current value for @param Symbol, or null if
80 const MCImm *GetSymbolValue(MCSymbol *Symbol) const;
82 void *Allocate(unsigned Size, unsigned Align = 8) {
83 return Allocator.Allocate(Size, Align);
85 void Deallocate(void *Ptr) {
89 } // end namespace llvm
91 // operator new and delete aren't allowed inside namespaces.
92 // The throw specifications are mandated by the standard.
93 /// @brief Placement new for using the MCContext's allocator.
95 /// This placement form of operator new uses the MCContext's allocator for
96 /// obtaining memory. It is a non-throwing new, which means that it returns
97 /// null on error. (If that is what the allocator does. The current does, so if
98 /// this ever changes, this operator will have to be changed, too.)
99 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
101 /// // Default alignment (16)
102 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
103 /// // Specific alignment
104 /// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
106 /// Please note that you cannot use delete on the pointer; it must be
107 /// deallocated using an explicit destructor call followed by
108 /// @c Context.Deallocate(Ptr).
110 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
111 /// @param C The MCContext that provides the allocator.
112 /// @param Alignment The alignment of the allocated memory (if the underlying
113 /// allocator supports it).
114 /// @return The allocated memory. Could be NULL.
115 inline void *operator new(size_t Bytes, llvm::MCContext &C,
116 size_t Alignment) throw () {
117 return C.Allocate(Bytes, Alignment);
119 /// @brief Placement delete companion to the new above.
121 /// This operator is just a companion to the new above. There is no way of
122 /// invoking it directly; see the new operator for more details. This operator
123 /// is called implicitly by the compiler if a placement new expression using
124 /// the MCContext throws in the object constructor.
125 inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
130 /// This placement form of operator new[] uses the MCContext's allocator for
131 /// obtaining memory. It is a non-throwing new[], which means that it returns
133 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
135 /// // Default alignment (16)
136 /// char *data = new (Context) char[10];
137 /// // Specific alignment
138 /// char *data = new (Context, 8) char[10];
140 /// Please note that you cannot use delete on the pointer; it must be
141 /// deallocated using an explicit destructor call followed by
142 /// @c Context.Deallocate(Ptr).
144 /// @param Bytes The number of bytes to allocate. Calculated by the compiler.
145 /// @param C The MCContext that provides the allocator.
146 /// @param Alignment The alignment of the allocated memory (if the underlying
147 /// allocator supports it).
148 /// @return The allocated memory. Could be NULL.
149 inline void *operator new[](size_t Bytes, llvm::MCContext& C,
150 size_t Alignment = 16) throw () {
151 return C.Allocate(Bytes, Alignment);
154 /// @brief Placement delete[] companion to the new[] above.
156 /// This operator is just a companion to the new[] above. There is no way of
157 /// invoking it directly; see the new[] operator for more details. This operator
158 /// is called implicitly by the compiler if a placement new[] expression using
159 /// the MCContext throws in the object constructor.
160 inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {