//===- llvm/System/Memory.h - Memory Support --------------------*- C++ -*-===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Reid Spencer and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This file declares the llvm::sys::Memory class.
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_SYSTEM_PATH_H
-#define LLVM_SYSTEM_PATH_H
+#ifndef LLVM_SYSTEM_MEMORY_H
+#define LLVM_SYSTEM_MEMORY_H
#include <string>
namespace llvm {
namespace sys {
- /// This class provides an abstraction for various memory handling functions
+ /// 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
+ /// @brief Memory block abstraction.
+ class MemoryBlock {
+ public:
+ void *base() const { return Address; }
+ unsigned size() const { return Size; }
+ private:
+ void *Address; ///< Address of first byte of memory area
+ unsigned 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
- /// @brief An abstraction for operating system paths.
+ /// @brief An abstraction for memory operations.
class Memory {
- /// @name Functions
- /// @{
- public:
- Memory() { Address = 0; AllocSize = 0; }
- ~Memory() { ReleaseRWX(*this); }
-
- /// @throws std::string if an error occurred
- static void* AllocateRWX(Memory& block, unsigned NumBytes);
-
- /// @throws std::string if an error occurred
- static void ReleaseRWX(Memory& block);
-
- char* base() const { return reinterpret_cast<char*>(Address); }
- unsigned size() const { return AllocSize; }
- /// @}
- /// @name Data
- /// @{
- private:
- void * Address; // Address of first byte of memory area
- unsigned AllocSize; // Size, in bytes of the memory area
- /// @}
+ public:
+ /// This method allocates a block of Read/Write/Execute memory that is
+ /// suitable for executing 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.
+ ///
+ /// On success, this returns a non-null memory block, otherwise it returns
+ /// a null memory block and fills in *ErrMsg.
+ ///
+ /// @brief Allocate Read/Write/Execute memory.
+ static MemoryBlock AllocateRWX(unsigned NumBytes,
+ const MemoryBlock *NearBlock,
+ std::string *ErrMsg = 0);
+
+ /// This method releases a block of Read/Write/Execute memory that was
+ /// allocated with the AllocateRWX method. It should not be used to
+ /// release any memory block allocated any other way.
+ ///
+ /// On success, this returns false, otherwise it returns true and fills
+ /// in *ErrMsg.
+ /// @throws std::string if an error occurred.
+ /// @brief Release Read/Write/Execute memory.
+ static bool ReleaseRWX(MemoryBlock &block, std::string *ErrMsg = 0);
+
+
+ /// 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);
+
+ /// setExecutable - Before the JIT can run a block of code, it has to be
+ /// given read and executable privilege. Return true if it is already r-x
+ /// or the system is able to change its previlege.
+ static bool setExecutable (MemoryBlock &M, std::string *ErrMsg = 0);
+
+ /// setWritable - When adding to a block of code, the JIT may need
+ /// to mark a block of code as RW since the protections are on page
+ /// boundaries, and the JIT internal allocations are not page aligned.
+ static bool setWritable (MemoryBlock &M, std::string *ErrMsg = 0);
+
+ /// setRangeExecutable - Mark the page containing a range of addresses
+ /// as executable.
+ static bool setRangeExecutable(const void *Addr, size_t Size);
+
+ /// setRangeWritable - Mark the page containing a range of addresses
+ /// as writable.
+ static bool setRangeWritable(const void *Addr, size_t Size);
};
}
}
-// vim: sw=2
-
#endif