Make the size() method const

llvm-svn: 18852
diff --git a/llvm/include/llvm/System/MappedFile.h b/llvm/include/llvm/System/MappedFile.h
index 526d11b..f73618a 100644
--- a/llvm/include/llvm/System/MappedFile.h
+++ b/llvm/include/llvm/System/MappedFile.h
@@ -94,7 +94,7 @@
 
     /// This function returns the number of bytes in the file. 
     /// @throws std::string if an error occurs
-    size_t size();
+    size_t size() const;
 
   /// @}
   /// @name Mutators
@@ -137,7 +137,7 @@
     sys::Path path_;       ///< Path to the file.
     int options_;          ///< Options used to create the mapping
     void* base_;           ///< Pointer to the base memory address
-    MappedFileInfo* info_; ///< Platform specific info for the mapping
+    mutable MappedFileInfo* info_; ///< Platform specific info for the mapping
 
   /// @}
   /// @name Disabled
diff --git a/llvm/lib/System/Unix/MappedFile.cpp b/llvm/lib/System/Unix/MappedFile.cpp
index 1c9622d..36a17e0 100644
--- a/llvm/lib/System/Unix/MappedFile.cpp
+++ b/llvm/lib/System/Unix/MappedFile.cpp
@@ -108,7 +108,7 @@
   return base_;
 }
 
-size_t MappedFile::size() {
+size_t MappedFile::size() const {
   assert(info_ && "MappedFile not initialized");
   return info_->sbuf_.st_size;
 }