am 31675153: Merge branch \'upstream\' into merge_2

* commit '31675153bd2d7617db8cb6aeb58054934c7b9f73': (542 commits)
  MaximumSpanningTree::EdgeWeightCompare: Make this comparator actually be a strict weak ordering, and don't pass possibly-null pointers to dyn_cast.
  Fix misaligned access in MachO object file reader: despite containing an int64_t, Symbol64TableEntry is actually only stored with 4-byte alignment within the file.
  Fix unaligned memory accesses when performing relocations in X86 JIT. There's no cost to using memcpy here: the fixed code is optimized by LLVM to perfect machine code.
  Don't pass a null pointer to cast<> in its unit tests.
  Don't bind a reference to a dereferenced null pointer (for return value of WeakVH::operator*).
  [ms-inline asm] Do not report a Parser error when matching inline assembly.
  Ignore the documentation-suggested location for compile_commands.json
  The presence of the empty file "foo" unfortunately does not improve LLVM in any way.
  Remove unnecessary cast that was also unnecessarily casting away constness.
  Provide a portability macro for __builtin_trap.
  Fix macros arguments with an underscore, dot or dollar in them. This is based on a patch by Andy/PaX. I added the support for dot and dollar.
  [ms-inline asm] Expose the ErrorInfo from the MatchInstructionImpl.  In general, this is the index of the operand that failed to match.
  Formatting.  No functional change.
  Make the wording in of the "expected identifier" error in the .macro directive consistent with the other "expected identifier" errors. Extracted from the Andy/PaX patch. I added the test.
  Pacify PVS-Studio by changing the type rather than doing a cast, a tweak suggested by David Blaikie.
  Add support for the --param ssp-buffer-size= driver option. PR9673
  Use typedefs. Fix indentation. Extracted from the Andy/PaX patch.
  Remove unused variable. Extracted from the Andy/PaX patch.
  Fix typo. Extracted from the Andy/PaX patch.
  MCJIT: Tidy up the constructor.
  ...

1 files changed, 77 insertions, 0 deletions

diff --git a/include/llvm/Support/FileSystem.h b/include/llvm/Support/FileSystem.h
index e0353f9..f4a9aa0 100644
--- a/include/llvm/Support/FileSystem.h
+++ b/include/llvm/Support/FileSystem.h
@@ -28,6 +28,7 @@
 #define LLVM_SUPPORT_FILE_SYSTEM_H
 
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
@@ -576,6 +577,82 @@ error_code FindLibrary(const Twine &short_name, SmallVectorImpl<char> &result);
 error_code GetMainExecutable(const char *argv0, void *MainAddr,
                              SmallVectorImpl<char> &result);
 
+/// This class represents a memory mapped file. It is based on
+/// boost::iostreams::mapped_file.
+class mapped_file_region {
+  mapped_file_region() LLVM_DELETED_FUNCTION;
+  mapped_file_region(mapped_file_region&) LLVM_DELETED_FUNCTION;
+  mapped_file_region &operator =(mapped_file_region&) LLVM_DELETED_FUNCTION;
+
+public:
+  enum mapmode {
+    readonly, //< May only access map via const_data as read only.
+    readwrite, //< May access map via data and modify it. Written to path.
+    priv //< May modify via data, but changes are lost on destruction.
+  };
+
+private:
+  /// Platform specific mapping state.
+  mapmode Mode;
+  uint64_t Size;
+  void *Mapping;
+#if LLVM_ON_WIN32
+  int FileDescriptor;
+  void *FileHandle;
+  void *FileMappingHandle;
+#endif
+
+  error_code init(int FD, uint64_t Offset);
+
+public:
+  typedef char char_type;
+
+#if LLVM_USE_RVALUE_REFERENCES
+  mapped_file_region(mapped_file_region&&);
+  mapped_file_region &operator =(mapped_file_region&&);
+#endif
+
+  /// Construct a mapped_file_region at \a path starting at \a offset of length
+  /// \a length and with access \a mode.
+  ///
+  /// \param path Path to the file to map. If it does not exist it will be
+  ///             created.
+  /// \param mode How to map the memory.
+  /// \param length Number of bytes to map in starting at \a offset. If the file
+  ///               is shorter than this, it will be extended. If \a length is
+  ///               0, the entire file will be mapped.
+  /// \param offset Byte offset from the beginning of the file where the map
+  ///               should begin. Must be a multiple of
+  ///               mapped_file_region::alignment().
+  /// \param ec This is set to errc::success if the map was constructed
+  ///           sucessfully. Otherwise it is set to a platform dependent error.
+  mapped_file_region(const Twine &path,
+                     mapmode mode,
+                     uint64_t length,
+                     uint64_t offset,
+                     error_code &ec);
+
+  /// \param fd An open file descriptor to map. mapped_file_region takes
+  ///           ownership. It must have been opended in the correct mode.
+  mapped_file_region(int fd,
+                     mapmode mode,
+                     uint64_t length,
+                     uint64_t offset,
+                     error_code &ec);
+
+  ~mapped_file_region();
+
+  mapmode flags() const;
+  uint64_t size() const;
+  char *data() const;
+
+  /// Get a const view of the data. Modifying this memory has undefined
+  /// behaivor.
+  const char *const_data() const;
+
+  /// \returns The minimum alignment offset must be.
+  static int alignment();
+};
 
 /// @brief Memory maps the contents of a file
 ///