cpphash.c (special_symbol): Represent an empty macro with "\r \r " not just "\r ".

	* cpphash.c (special_symbol): Represent an empty macro with
	"\r \r " not just "\r ".
	(_cpp_macroexpand): Correct condition for the foo ( ) special
	case.
	(unsafe_chars): Handle EOF as second argument.
	(push_macro_expansion): Simplify test for removing escape at
	end.  Do not trim both escapes if there is no text in between.

	* gcc.dg/20000419-1.c: New test.

From-SVN: r33267

gcc/ChangeLog

+2000-04-19  Zack Weinberg  <zack@wolery.cumb.org>
+
+	* cpphash.c (special_symbol): Represent an empty macro with
+	"\r \r " not just "\r ".
+	(_cpp_macroexpand): Correct condition for the foo ( ) special
+	case.
+	(unsafe_chars): Handle EOF as second argument.
+	(push_macro_expansion): Simplify test for removing escape at
+	end.  Do not trim both escapes if there is no text in between.
+
 2000-04-19  Jim Blandy  <jimb@redhat.com>
 
 	* dwarf2out.c (DWARF2_ADDR_SIZE): New macro.  Use it instead

gcc/cpphash.c

@@ -908,7 +908,7 @@ special_symbol (hp, pfile)
       if (!buf)
 	return;
       if (*buf == '\0')
-	buf = "\r ";
+	buf = "\r \r ";
 
       CPP_PUTS (pfile, buf, strlen (buf));
       return;
@@ -1075,14 +1075,14 @@ _cpp_macroexpand (pfile, hp)
       if (token != CPP_RPAREN)
 	return;
 
-      /* If we got one arg but it was just whitespace, call that 0 args.  */
-      if (i == 1)
+      /* foo ( ) is equivalent to foo () unless foo takes exactly one
+	 argument, in which case the former is allowed and the latter
+	 is not.  XXX C99 is silent on this rule, but it seems
+	 inconsistent to me.  */
+      if (i == 1 && nargs != 1)
 	{
 	  register U_CHAR *bp = ARG_BASE + args[0].raw;
 	  register U_CHAR *lim = bp + args[0].raw_length;
-	  /* cpp.texi says for foo ( ) we provide one argument.
-	     However, if foo wants just 0 arguments, treat this as 0.  */
-	  if (nargs == 0)
 	    while (bp != lim && is_space(*bp))
 	      bp++;
 	  if (bp == lim)
@@ -1410,6 +1410,10 @@ unsafe_chars (pfile, c1, c2)
      cpp_reader *pfile;
      int c1, c2;
 {
+  /* If c2 is EOF, that's always safe.  */
+  if (c2 == EOF)
+    return 0;
+
   switch (c1)
     {
     case EOF:
@@ -1491,14 +1495,13 @@ push_macro_expansion (pfile, xbuf, len, hp)
   /* Likewise, avoid the extra space at the end of the macro expansion
      if this is safe.  We can do a better job here since we can know
      what the next char will be.  */
-  if (len >= 3
-      && xbuf[len-2] == '\r'
-      && xbuf[len-1] == ' ')
-    {
-      int c = CPP_BUF_PEEK (CPP_BUFFER (pfile));
-      if (c == EOF || !unsafe_chars (pfile, xbuf[len-3], c))
-	len -= 2;
-    }
+  if (len >= 3 && xbuf[len-2] == '\r' && xbuf[len-1] == ' '
+      && !unsafe_chars (pfile, xbuf[len-3], CPP_BUF_PEEK (CPP_BUFFER (pfile))))
+    len -= 2;
+
+  /* If the total expansion is "\r \r", we must not trim both escapes.  */
+  if (len == 2 && advance_cur)
+    advance_cur = 0;
 
   mbuf = cpp_push_buffer (pfile, xbuf, len);
   if (mbuf == NULL)

gcc/testsuite/ChangeLog

+2000-04-19  Zack Weinberg  <zack@wolery.cumb.org>
+
+	* gcc.dg/20000419-1.c: New test.
+
 Wed Apr 12 10:25:08 2000  Jeffrey A Law  (law@cygnus.com)
 
 	* gcc.c-torture/execute/20000412-5.c: New test.

gcc/testsuite/gcc.dg/20000419-1.c

+/* Test for erroneous deletion of the entire macro expansion when pruning
+   \r escapes.  Problem noted by DJ Delorie <dj@delorie.com>; test case
+   distilled from GNU libc header files.  */
+/* { dg-do preprocess } */
+
+#define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
+#define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
+#define __ASMNAME2(prefix, cname) __STRING (prefix) cname
+#define __STRING(x)    #x
+
+__REDIRECT (a, b, c)
+__ASMNAME2 (__USER_LABEL_PREFIX__, harumph)
+
+/* { dg-bogus "used without args" "no args, 1" { target native } 11 } */
+/* { dg-bogus "used without args" "no args, 1" { target native } 12 } */