Vendor import of llvm trunk r126079:vendor/llvm/llvm-r126079

http://llvm.org/svn/llvm-project/llvm/trunk@126079

1 files changed, 96 insertions, 0 deletions

diff --git a/include/llvm/Support/Memory.h b/include/llvm/Support/Memory.h
new file mode 100644
index 000000000000..9c3f85b958bc
--- /dev/null
+++ b/include/llvm/Support/Memory.h
@@ -0,0 +1,96 @@
+//===- llvm/Support/Memory.h - Memory Support --------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// 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_MEMORY_H
+#define LLVM_SYSTEM_MEMORY_H
+
+#include "llvm/Support/DataTypes.h"
+#include <string>
+
+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
+  /// @brief Memory block abstraction.
+  class MemoryBlock {
+  public:
+    MemoryBlock() : Address(0), 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
+  /// @brief An abstraction for memory operations.
+  class Memory {
+  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(size_t 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.
+    /// @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);
+  };
+}
+}
+
+#endif