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//===- MCContext.h - Machine Code Context -----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCCONTEXT_H
#define LLVM_MC_MCCONTEXT_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Allocator.h"
namespace llvm {
class MCExpr;
class MCSection;
class MCSymbol;
class StringRef;
class Twine;
/// MCContext - Context object for machine code objects. This class owns all
/// of the sections that it creates.
///
class MCContext {
MCContext(const MCContext&); // DO NOT IMPLEMENT
MCContext &operator=(const MCContext&); // DO NOT IMPLEMENT
/// Sections - Bindings of names to allocated sections.
StringMap<MCSection*> Sections;
/// Symbols - Bindings of names to symbols.
StringMap<MCSymbol*> Symbols;
/// Allocator - Allocator object used for creating machine code objects.
///
/// We use a bump pointer allocator to avoid the need to track all allocated
/// objects.
BumpPtrAllocator Allocator;
public:
MCContext();
~MCContext();
/// @name Symbol Managment
/// @{
/// CreateSymbol - Create a new symbol with the specified @p Name.
///
/// @param Name - The symbol name, which must be unique across all symbols.
MCSymbol *CreateSymbol(StringRef Name);
/// GetOrCreateSymbol - Lookup the symbol inside with the specified
/// @p Name. If it exists, return it. If not, create a forward
/// reference and return it.
///
/// @param Name - The symbol name, which must be unique across all symbols.
MCSymbol *GetOrCreateSymbol(StringRef Name);
MCSymbol *GetOrCreateSymbol(const Twine &Name);
/// CreateTemporarySymbol - Create a new temporary symbol with the specified
/// @p Name.
///
/// @param Name - The symbol name, for debugging purposes only, temporary
/// symbols do not surive assembly. If non-empty the name must be unique
/// across all symbols.
MCSymbol *CreateTemporarySymbol(StringRef Name = "");
/// LookupSymbol - Get the symbol for \p Name, or null.
MCSymbol *LookupSymbol(StringRef Name) const;
/// @}
void *Allocate(unsigned Size, unsigned Align = 8) {
return Allocator.Allocate(Size, Align);
}
void Deallocate(void *Ptr) {
}
};
} // end namespace llvm
// operator new and delete aren't allowed inside namespaces.
// The throw specifications are mandated by the standard.
/// @brief Placement new for using the MCContext's allocator.
///
/// This placement form of operator new uses the MCContext's allocator for
/// obtaining memory. It is a non-throwing new, which means that it returns
/// null on error. (If that is what the allocator does. The current does, so if
/// this ever changes, this operator will have to be changed, too.)
/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
/// @code
/// // Default alignment (16)
/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
/// // Specific alignment
/// IntegerLiteral *Ex2 = new (Context, 8) IntegerLiteral(arguments);
/// @endcode
/// Please note that you cannot use delete on the pointer; it must be
/// deallocated using an explicit destructor call followed by
/// @c Context.Deallocate(Ptr).
///
/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
/// @param C The MCContext that provides the allocator.
/// @param Alignment The alignment of the allocated memory (if the underlying
/// allocator supports it).
/// @return The allocated memory. Could be NULL.
inline void *operator new(size_t Bytes, llvm::MCContext &C,
size_t Alignment = 16) throw () {
return C.Allocate(Bytes, Alignment);
}
/// @brief Placement delete companion to the new above.
///
/// This operator is just a companion to the new above. There is no way of
/// invoking it directly; see the new operator for more details. This operator
/// is called implicitly by the compiler if a placement new expression using
/// the MCContext throws in the object constructor.
inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
throw () {
C.Deallocate(Ptr);
}
/// This placement form of operator new[] uses the MCContext's allocator for
/// obtaining memory. It is a non-throwing new[], which means that it returns
/// null on error.
/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
/// @code
/// // Default alignment (16)
/// char *data = new (Context) char[10];
/// // Specific alignment
/// char *data = new (Context, 8) char[10];
/// @endcode
/// Please note that you cannot use delete on the pointer; it must be
/// deallocated using an explicit destructor call followed by
/// @c Context.Deallocate(Ptr).
///
/// @param Bytes The number of bytes to allocate. Calculated by the compiler.
/// @param C The MCContext that provides the allocator.
/// @param Alignment The alignment of the allocated memory (if the underlying
/// allocator supports it).
/// @return The allocated memory. Could be NULL.
inline void *operator new[](size_t Bytes, llvm::MCContext& C,
size_t Alignment = 16) throw () {
return C.Allocate(Bytes, Alignment);
}
/// @brief Placement delete[] companion to the new[] above.
///
/// This operator is just a companion to the new[] above. There is no way of
/// invoking it directly; see the new[] operator for more details. This operator
/// is called implicitly by the compiler if a placement new[] expression using
/// the MCContext throws in the object constructor.
inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
C.Deallocate(Ptr);
}
#endif
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