d: Fix D lexer sometimes fails to compile code read from stdin

As of gdc-12, the lexer expects there 4 bytes of zero padding at the end
of the source buffer to mark the end of input.  Sometimes when reading
from stdin, the data at the end of input is garbage rather than zeroes.
Fix that by explicitly calling memset past the end of the buffer.

	PR d/105544

gcc/d/ChangeLog:

	* d-lang.cc (d_parse_file): Zero padding past the end of the stdin
	buffer so the D lexer has a sentinel to stop parsing at.

diff --git a/gcc/d/d-lang.cc b/gcc/d/d-lang.cc
index ef0fe0b8adb742839f00e63b8b75a747ab8720b3..b7c8685f779dd2753403c77ef5ce170de0dedce9 100644 (file)
--- a/gcc/d/d-lang.cc
+++ b/gcc/d/d-lang.cc
@@ -1077,6 +1077,10 @@ d_parse_file (void)
                                      global.params.dihdr.doOutput);
          modules.push (m);
 
+         /* Zero the padding past the end of the buffer so the D lexer has a
+            sentinel.  The lexer only reads up to 4 bytes at a time.  */
+         memset (buffer + len, '\0', 16);
+
          /* Overwrite the source file for the module, the one created by
             Module::create would have a forced a `.d' suffix.  */
          m->src.length = len;