MCContext.h revision 205218
1195098Sed//===- MCContext.h - Machine Code Context -----------------------*- C++ -*-===// 2195098Sed// 3195098Sed// The LLVM Compiler Infrastructure 4195098Sed// 5195098Sed// This file is distributed under the University of Illinois Open Source 6195098Sed// License. See LICENSE.TXT for details. 7195098Sed// 8195098Sed//===----------------------------------------------------------------------===// 9195098Sed 10195098Sed#ifndef LLVM_MC_MCCONTEXT_H 11195098Sed#define LLVM_MC_MCCONTEXT_H 12195098Sed 13195098Sed#include "llvm/ADT/DenseMap.h" 14195098Sed#include "llvm/ADT/StringMap.h" 15195098Sed#include "llvm/Support/Allocator.h" 16195098Sed 17195098Sednamespace llvm { 18205218Srdivacky class MCAsmInfo; 19198396Srdivacky class MCExpr; 20195098Sed class MCSection; 21195098Sed class MCSymbol; 22198090Srdivacky class StringRef; 23198396Srdivacky class Twine; 24195098Sed 25198090Srdivacky /// MCContext - Context object for machine code objects. This class owns all 26198090Srdivacky /// of the sections that it creates. 27198090Srdivacky /// 28195098Sed class MCContext { 29195098Sed MCContext(const MCContext&); // DO NOT IMPLEMENT 30195098Sed MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT 31195098Sed 32205218Srdivacky /// The MCAsmInfo for this target. 33205218Srdivacky const MCAsmInfo &MAI; 34205218Srdivacky 35195098Sed /// Sections - Bindings of names to allocated sections. 36195098Sed StringMap<MCSection*> Sections; 37195098Sed 38195098Sed /// Symbols - Bindings of names to symbols. 39195098Sed StringMap<MCSymbol*> Symbols; 40195098Sed 41205218Srdivacky /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary 42205218Srdivacky /// symbol. 43205218Srdivacky unsigned NextUniqueID; 44205218Srdivacky 45195098Sed /// Allocator - Allocator object used for creating machine code objects. 46195098Sed /// 47195098Sed /// We use a bump pointer allocator to avoid the need to track all allocated 48195098Sed /// objects. 49195098Sed BumpPtrAllocator Allocator; 50195098Sed public: 51205218Srdivacky explicit MCContext(const MCAsmInfo &MAI); 52195098Sed ~MCContext(); 53205218Srdivacky 54205218Srdivacky const MCAsmInfo &getAsmInfo() const { return MAI; } 55195098Sed 56198090Srdivacky /// @name Symbol Managment 57198090Srdivacky /// @{ 58205218Srdivacky 59205218Srdivacky /// CreateTempSymbol - Create and return a new assembler temporary symbol 60205218Srdivacky /// with a unique but unspecified name. 61205218Srdivacky MCSymbol *CreateTempSymbol(); 62198090Srdivacky 63195098Sed /// GetOrCreateSymbol - Lookup the symbol inside with the specified 64204642Srdivacky /// @p Name. If it exists, return it. If not, create a forward 65195098Sed /// reference and return it. 66195098Sed /// 67195098Sed /// @param Name - The symbol name, which must be unique across all symbols. 68205218Srdivacky MCSymbol *GetOrCreateSymbol(StringRef Name, bool isTemporary = false); 69205218Srdivacky MCSymbol *GetOrCreateSymbol(const Twine &Name, bool isTemporary = false); 70198396Srdivacky 71204961Srdivacky /// GetOrCreateTemporarySymbol - Create a new assembler temporary symbol 72204961Srdivacky /// with the specified @p Name if it doesn't exist or return the existing 73204961Srdivacky /// one if it does. 74195098Sed /// 75195098Sed /// @param Name - The symbol name, for debugging purposes only, temporary 76195098Sed /// symbols do not surive assembly. If non-empty the name must be unique 77195098Sed /// across all symbols. 78204961Srdivacky MCSymbol *GetOrCreateTemporarySymbol(StringRef Name = ""); 79204961Srdivacky MCSymbol *GetOrCreateTemporarySymbol(const Twine &Name); 80195098Sed 81204642Srdivacky /// LookupSymbol - Get the symbol for \p Name, or null. 82199481Srdivacky MCSymbol *LookupSymbol(StringRef Name) const; 83195098Sed 84198090Srdivacky /// @} 85195098Sed 86195098Sed void *Allocate(unsigned Size, unsigned Align = 8) { 87195098Sed return Allocator.Allocate(Size, Align); 88195098Sed } 89198396Srdivacky void Deallocate(void *Ptr) { 90195098Sed } 91195098Sed }; 92195098Sed 93195098Sed} // end namespace llvm 94195098Sed 95195098Sed// operator new and delete aren't allowed inside namespaces. 96195098Sed// The throw specifications are mandated by the standard. 97195098Sed/// @brief Placement new for using the MCContext's allocator. 98195098Sed/// 99195098Sed/// This placement form of operator new uses the MCContext's allocator for 100195098Sed/// obtaining memory. It is a non-throwing new, which means that it returns 101195098Sed/// null on error. (If that is what the allocator does. The current does, so if 102195098Sed/// this ever changes, this operator will have to be changed, too.) 103195098Sed/// Usage looks like this (assuming there's an MCContext 'Context' in scope): 104195098Sed/// @code 105195098Sed/// // Default alignment (16) 106195098Sed/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments); 107195098Sed/// // Specific alignment 108195098Sed/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments); 109195098Sed/// @endcode 110195098Sed/// Please note that you cannot use delete on the pointer; it must be 111195098Sed/// deallocated using an explicit destructor call followed by 112195098Sed/// @c Context.Deallocate(Ptr). 113195098Sed/// 114195098Sed/// @param Bytes The number of bytes to allocate. Calculated by the compiler. 115195098Sed/// @param C The MCContext that provides the allocator. 116195098Sed/// @param Alignment The alignment of the allocated memory (if the underlying 117195098Sed/// allocator supports it). 118195098Sed/// @return The allocated memory. Could be NULL. 119195098Sedinline void *operator new(size_t Bytes, llvm::MCContext &C, 120195098Sed size_t Alignment = 16) throw () { 121195098Sed return C.Allocate(Bytes, Alignment); 122195098Sed} 123195098Sed/// @brief Placement delete companion to the new above. 124195098Sed/// 125195098Sed/// This operator is just a companion to the new above. There is no way of 126195098Sed/// invoking it directly; see the new operator for more details. This operator 127195098Sed/// is called implicitly by the compiler if a placement new expression using 128195098Sed/// the MCContext throws in the object constructor. 129195098Sedinline void operator delete(void *Ptr, llvm::MCContext &C, size_t) 130195098Sed throw () { 131195098Sed C.Deallocate(Ptr); 132195098Sed} 133195098Sed 134195098Sed/// This placement form of operator new[] uses the MCContext's allocator for 135195098Sed/// obtaining memory. It is a non-throwing new[], which means that it returns 136195098Sed/// null on error. 137195098Sed/// Usage looks like this (assuming there's an MCContext 'Context' in scope): 138195098Sed/// @code 139195098Sed/// // Default alignment (16) 140195098Sed/// char *data = new (Context) char[10]; 141195098Sed/// // Specific alignment 142195098Sed/// char *data = new (Context, 8) char[10]; 143195098Sed/// @endcode 144195098Sed/// Please note that you cannot use delete on the pointer; it must be 145195098Sed/// deallocated using an explicit destructor call followed by 146195098Sed/// @c Context.Deallocate(Ptr). 147195098Sed/// 148195098Sed/// @param Bytes The number of bytes to allocate. Calculated by the compiler. 149195098Sed/// @param C The MCContext that provides the allocator. 150195098Sed/// @param Alignment The alignment of the allocated memory (if the underlying 151195098Sed/// allocator supports it). 152195098Sed/// @return The allocated memory. Could be NULL. 153195098Sedinline void *operator new[](size_t Bytes, llvm::MCContext& C, 154195098Sed size_t Alignment = 16) throw () { 155195098Sed return C.Allocate(Bytes, Alignment); 156195098Sed} 157195098Sed 158195098Sed/// @brief Placement delete[] companion to the new[] above. 159195098Sed/// 160195098Sed/// This operator is just a companion to the new[] above. There is no way of 161195098Sed/// invoking it directly; see the new[] operator for more details. This operator 162195098Sed/// is called implicitly by the compiler if a placement new[] expression using 163195098Sed/// the MCContext throws in the object constructor. 164195098Sedinline void operator delete[](void *Ptr, llvm::MCContext &C) throw () { 165195098Sed C.Deallocate(Ptr); 166195098Sed} 167195098Sed 168195098Sed#endif 169