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.
35 // FIXME: Is there a good reason to not just put this in the MCSymbol?
36 DenseMap<MCSymbol*, MCValue> SymbolValues;
38 /// Allocator - Allocator object used for creating machine code objects.
40 /// We use a bump pointer allocator to avoid the need to track all allocated
42 BumpPtrAllocator Allocator;
48 /// GetSection - Get or create a new section with the given @param Name.
49 MCSection *GetSection(const char *Name);
51 /// CreateSymbol - Create a new symbol with the specified @param Name.
53 /// @param Name - The symbol name, which must be unique across all symbols.
54 MCSymbol *CreateSymbol(const char *Name);
56 /// GetOrCreateSymbol - Lookup the symbol inside with the specified
57 /// @param Name. If it exists, return it. If not, create a forward
58 /// reference and return it.
60 /// @param Name - The symbol name, which must be unique across all symbols.
61 MCSymbol *GetOrCreateSymbol(const char *Name);
63 /// CreateTemporarySymbol - Create a new temporary symbol with the specified
66 /// @param Name - The symbol name, for debugging purposes only, temporary
67 /// symbols do not surive assembly. If non-empty the name must be unique
68 /// across all symbols.
69 MCSymbol *CreateTemporarySymbol(const char *Name = "");
71 /// LookupSymbol - Get the symbol for @param Name, or null.
72 MCSymbol *LookupSymbol(const char *Name) const;
74 /// ClearSymbolValue - Erase a value binding for @param Symbol, if one
76 void ClearSymbolValue(MCSymbol *Symbol);
78 /// SetSymbolValue - Set the value binding for @param Symbol to @param
80 void SetSymbolValue(MCSymbol *Symbol, const MCValue &Value);
82 /// GetSymbolValue - Return the current value for @param Symbol, or null if
84 const MCValue *GetSymbolValue(MCSymbol *Symbol) 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 () {