[clang] Use -Wshorten-64-to-32 to enable warnings about 64bit to 32bit truncations.

tools/shell-utils.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Utility functions used by parser-shell.
 
+#include "src/globals.h"
+
 #include <stdio.h>
 
 namespace v8 {
 namespace internal {
 
 enum Encoding {
   LATIN1,
   UTF8,
   UTF16
 };
 
 const byte* ReadFileAndRepeat(const char* name, int* size, int repeat) {
   FILE* file = fopen(name, "rb");
   *size = 0;
   if (file == NULL) return NULL;
 
   fseek(file, 0, SEEK_END);
-  int file_size = ftell(file);
+  int file_size = static_cast<int>(ftell(file));
   rewind(file);
 
   *size = file_size * repeat;
 
   byte* chars = new byte[*size + 1];
   for (int i = 0; i < file_size;) {
     int read = static_cast<int>(fread(&chars[i], 1, file_size - i, file));
     i += read;
   }
   fclose(file);
 
   for (int i = file_size; i < *size; i++) {
     chars[i] = chars[i - file_size];
   }
   chars[*size] = 0;
 
   return chars;
 }
 
 } }  // namespace v8::internal