MCJIT: Add faux remote target execution to lli for the MCJIT.

Simulate a remote target address space by allocating a seperate chunk of
memory for the target and re-mapping section addresses to that prior to
execution. Later we'll want to have a truly remote process, but for now
this gets us closer to being able to test the remote target
functionality outside LLDB.

rdar://12157052

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163216 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 101 insertions, 0 deletions

diff --git a/tools/lli/RemoteTarget.h b/tools/lli/RemoteTarget.h
new file mode 100644
index 0000000000..f4dcf42ebe
--- /dev/null
+++ b/tools/lli/RemoteTarget.h
@@ -0,0 +1,101 @@
+//===- RemoteTarget.h - LLVM Remote process JIT execution ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Definition of the RemoteTarget class which executes JITed code in a
+// separate address range from where it was built.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef REMOTEPROCESS_H
+#define REMOTEPROCESS_H
+
+#include <llvm/ADT/StringRef.h>
+#include <llvm/ADT/SmallVector.h>
+#include <llvm/Support/Memory.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string>
+
+namespace llvm {
+
+class RemoteTarget {
+  std::string ErrorMsg;
+  bool IsRunning;
+
+  SmallVector<sys::MemoryBlock, 16> Allocations;
+
+public:
+  StringRef getErrorMsg() const { return ErrorMsg; }
+
+  /// Allocate space in the remote target address space.
+  ///
+  /// @param      Size      Amount of space, in bytes, to allocate.
+  /// @param      Alignment Required minimum alignment for allocated space.
+  /// @param[out] Address   Remote address of the allocated memory.
+  ///
+  /// @returns False on success. On failure, ErrorMsg is updated with
+  ///          descriptive text of the encountered error.
+  bool allocateSpace(size_t Size, unsigned Alignment, uint64_t &Address);
+
+  /// Load data into the target address space.
+  ///
+  /// @param      Address   Destination address in the target process.
+  /// @param      Data      Source address in the host process.
+  /// @param      Size      Number of bytes to copy.
+  ///
+  /// @returns False on success. On failure, ErrorMsg is updated with
+  ///          descriptive text of the encountered error.
+  bool loadData(uint64_t Address, const void *Data, size_t Size);
+
+  /// Load code into the target address space and prepare it for execution.
+  ///
+  /// @param      Address   Destination address in the target process.
+  /// @param      Data      Source address in the host process.
+  /// @param      Size      Number of bytes to copy.
+  ///
+  /// @returns False on success. On failure, ErrorMsg is updated with
+  ///          descriptive text of the encountered error.
+  bool loadCode(uint64_t Address, const void *Data, size_t Size);
+
+  /// Execute code in the target process. The called function is required
+  /// to be of signature int "(*)(void)".
+  ///
+  /// @param      Address   Address of the loaded function in the target
+  ///                       process.
+  /// @param[out] RetVal    The integer return value of the called function.
+  ///
+  /// @returns False on success. On failure, ErrorMsg is updated with
+  ///          descriptive text of the encountered error.
+  bool executeCode(uint64_t Address, int &RetVal);
+
+  /// Minimum alignment for memory permissions. Used to seperate code and
+  /// data regions to make sure data doesn't get marked as code or vice
+  /// versa.
+  ///
+  /// @returns Page alignment return value. Default of 4k.
+  unsigned getPageAlignment() { return 4096; }
+
+  /// Start the remote process.
+  void create();
+
+  /// Terminate the remote process.
+  void stop();
+
+  RemoteTarget() : ErrorMsg(""), IsRunning(false) {}
+  ~RemoteTarget() { if (IsRunning) stop(); }
+
+private:
+  // Main processing function for the remote target process. Command messages
+  // are received on file descriptor CmdFD and responses come back on OutFD.
+  static void doRemoteTargeting(int CmdFD, int OutFD);
+};
+
+} // end namespace llvm
+
+#endif