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Diffstat (limited to 'clang-r353983/include/llvm/Support/Memory.h')
| -rw-r--r-- | clang-r353983/include/llvm/Support/Memory.h | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/clang-r353983/include/llvm/Support/Memory.h b/clang-r353983/include/llvm/Support/Memory.h new file mode 100644 index 00000000..2f4cafe4 --- /dev/null +++ b/clang-r353983/include/llvm/Support/Memory.h @@ -0,0 +1,144 @@ +//===- llvm/Support/Memory.h - Memory Support -------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file declares the llvm::sys::Memory class. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_MEMORY_H +#define LLVM_SUPPORT_MEMORY_H + +#include "llvm/Support/DataTypes.h" +#include <string> +#include <system_error> + +namespace llvm { +namespace sys { + + /// This class encapsulates the notion of a memory block which has an address + /// and a size. It is used by the Memory class (a friend) as the result of + /// various memory allocation operations. + /// @see Memory + /// Memory block abstraction. + class MemoryBlock { + public: + MemoryBlock() : Address(nullptr), Size(0) { } + MemoryBlock(void *addr, size_t size) : Address(addr), Size(size) { } + void *base() const { return Address; } + size_t size() const { return Size; } + + private: + void *Address; ///< Address of first byte of memory area + size_t Size; ///< Size, in bytes of the memory area + friend class Memory; + }; + + /// This class provides various memory handling functions that manipulate + /// MemoryBlock instances. + /// @since 1.4 + /// An abstraction for memory operations. + class Memory { + public: + enum ProtectionFlags { + MF_READ = 0x1000000, + MF_WRITE = 0x2000000, + MF_EXEC = 0x4000000 + }; + + /// This method allocates a block of memory that is suitable for loading + /// dynamically generated code (e.g. JIT). An attempt to allocate + /// \p NumBytes bytes of virtual memory is made. + /// \p NearBlock may point to an existing allocation in which case + /// an attempt is made to allocate more memory near the existing block. + /// The actual allocated address is not guaranteed to be near the requested + /// address. + /// \p Flags is used to set the initial protection flags for the block + /// of the memory. + /// \p EC [out] returns an object describing any error that occurs. + /// + /// This method may allocate more than the number of bytes requested. The + /// actual number of bytes allocated is indicated in the returned + /// MemoryBlock. + /// + /// The start of the allocated block must be aligned with the + /// system allocation granularity (64K on Windows, page size on Linux). + /// If the address following \p NearBlock is not so aligned, it will be + /// rounded up to the next allocation granularity boundary. + /// + /// \r a non-null MemoryBlock if the function was successful, + /// otherwise a null MemoryBlock is with \p EC describing the error. + /// + /// Allocate mapped memory. + static MemoryBlock allocateMappedMemory(size_t NumBytes, + const MemoryBlock *const NearBlock, + unsigned Flags, + std::error_code &EC); + + /// This method releases a block of memory that was allocated with the + /// allocateMappedMemory method. It should not be used to release any + /// memory block allocated any other way. + /// \p Block describes the memory to be released. + /// + /// \r error_success if the function was successful, or an error_code + /// describing the failure if an error occurred. + /// + /// Release mapped memory. + static std::error_code releaseMappedMemory(MemoryBlock &Block); + + /// This method sets the protection flags for a block of memory to the + /// state specified by /p Flags. The behavior is not specified if the + /// memory was not allocated using the allocateMappedMemory method. + /// \p Block describes the memory block to be protected. + /// \p Flags specifies the new protection state to be assigned to the block. + /// \p ErrMsg [out] returns a string describing any error that occurred. + /// + /// If \p Flags is MF_WRITE, the actual behavior varies + /// with the operating system (i.e. MF_READ | MF_WRITE on Windows) and the + /// target architecture (i.e. MF_WRITE -> MF_READ | MF_WRITE on i386). + /// + /// \r error_success if the function was successful, or an error_code + /// describing the failure if an error occurred. + /// + /// Set memory protection state. + static std::error_code protectMappedMemory(const MemoryBlock &Block, + unsigned Flags); + + /// InvalidateInstructionCache - Before the JIT can run a block of code + /// that has been emitted it must invalidate the instruction cache on some + /// platforms. + static void InvalidateInstructionCache(const void *Addr, size_t Len); + }; + + /// Owning version of MemoryBlock. + class OwningMemoryBlock { + public: + OwningMemoryBlock() = default; + explicit OwningMemoryBlock(MemoryBlock M) : M(M) {} + OwningMemoryBlock(OwningMemoryBlock &&Other) { + M = Other.M; + Other.M = MemoryBlock(); + } + OwningMemoryBlock& operator=(OwningMemoryBlock &&Other) { + M = Other.M; + Other.M = MemoryBlock(); + return *this; + } + ~OwningMemoryBlock() { + Memory::releaseMappedMemory(M); + } + void *base() const { return M.base(); } + size_t size() const { return M.size(); } + MemoryBlock getMemoryBlock() const { return M; } + private: + MemoryBlock M; + }; + +} +} + +#endif |
