PR bootstrap/55380

	PR other/54691
	* files.c (read_file_guts): Allocate extra 16 bytes instead of
	1 byte at the end of buf.  Pass size + 16 instead of size
	to _cpp_convert_input.
	* charset.c (_cpp_convert_input): Reallocate if there aren't
	at least 16 bytes beyond to.len in the buffer.  Clear 16 bytes
	at to.text + to.len.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@194102 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 7 insertions, 3 deletions

diff --git a/libcpp/files.c b/libcpp/files.c
index 9f84d8c6e02..3aeb6f37881 100644
--- a/libcpp/files.c
+++ b/libcpp/files.c
@@ -671,7 +671,11 @@ read_file_guts (cpp_reader *pfile, _cpp_file *file)
        the majority of C source files.  */
     size = 8 * 1024;
 
-  buf = XNEWVEC (uchar, size + 1);
+  /* The + 16 here is space for the final '\n' and 15 bytes of padding,
+     used to quiet warnings from valgrind or Address Sanitizer, when the
+     optimized lexer accesses aligned 16-byte memory chunks, including
+     the bytes after the malloced, area, and stops lexing on '\n'.  */
+  buf = XNEWVEC (uchar, size + 16);
   total = 0;
   while ((count = read (file->fd, buf + total, size - total)) > 0)
     {
@@ -682,7 +686,7 @@ read_file_guts (cpp_reader *pfile, _cpp_file *file)
 	  if (regular)
 	    break;
 	  size *= 2;
-	  buf = XRESIZEVEC (uchar, buf, size + 1);
+	  buf = XRESIZEVEC (uchar, buf, size + 16);
 	}
     }
 
@@ -699,7 +703,7 @@ read_file_guts (cpp_reader *pfile, _cpp_file *file)
 
   file->buffer = _cpp_convert_input (pfile,
 				     CPP_OPTION (pfile, input_charset),
-				     buf, size, total,
+				     buf, size + 16, total,
 				     &file->buffer_start,
 				     &file->st.st_size);
   file->buffer_valid = true;