cpplib.h (CPP_POP, [...]): Delete.

	* cpplib.h (CPP_POP, parse_cleanup_t): Delete.
	(cpp_buffer): Remove cleanup, seen_eof, manual_pop members.

	* cppfiles.c (file_cleanup): Delete.
	* cpphash.c (macro_cleanup): Delete.
	(collect_objlike_expansion, collect_funlike_expansion,
	macarg, scan_arguments): Remove CPP_POP case.

	* cpplex.c (null_cleanup): Delete.
	(cpp_pop_buffer): Do the work that was done in the cleanups
	here.  Call _cpp_unwind_if_stack from here.
	(_cpp_expand_to_buffer, cpp_scan_buffer_nooutput,
	cpp_scan_buffer): Run until we see CPP_EOF and the top of
	stack is the buffer _below_ the one we stacked.
	(cpp_get_token): Always pop an exhausted buffer.  Return
	CPP_EOF unless it's a macro buffer.  Don't call _cpp_handle_eof.
	* cpplib.c (skip_if_group): Don't call cpp_get_token to
	increment the line number.
	(_cpp_handle_eof): Rename to _cpp_unwind_if_stack.

	* fix-header.c (read_scan_file) [parsing getchar()]: Run until
	we see CPP_EOF and the top of stack is the buffer _below_ the
	one we stacked.
	* scan-decls.c: Likewise.

From-SVN: r33611

gcc/ChangeLog

+2000-05-02  Zack Weinberg  <zack@wolery.cumb.org>
+
+	* cpplib.h (CPP_POP, parse_cleanup_t): Delete.
+	(cpp_buffer): Remove cleanup, seen_eof, manual_pop members.
+
+	* cppfiles.c (file_cleanup): Delete.
+	* cpphash.c (macro_cleanup): Delete.
+	(collect_objlike_expansion, collect_funlike_expansion,
+	macarg, scan_arguments): Remove CPP_POP case.
+
+	* cpplex.c (null_cleanup): Delete.
+	(cpp_pop_buffer): Do the work that was done in the cleanups
+	here.  Call _cpp_unwind_if_stack from here.
+	(_cpp_expand_to_buffer, cpp_scan_buffer_nooutput,
+	cpp_scan_buffer): Run until we see CPP_EOF and the top of
+	stack is the buffer _below_ the one we stacked.
+	(cpp_get_token): Always pop an exhausted buffer.  Return
+	CPP_EOF unless it's a macro buffer.  Don't call _cpp_handle_eof.
+	* cpplib.c (skip_if_group): Don't call cpp_get_token to
+	increment the line number.
+	(_cpp_handle_eof): Rename to _cpp_unwind_if_stack.
+
+	* fix-header.c (read_scan_file) [parsing getchar()]: Run until
+	we see CPP_EOF and the top of stack is the buffer _below_ the
+	one we stacked.
+	* scan-decls.c: Likewise.
+
 2000-05-02  Andrew Haley  <aph@cygnus.com>
 
 	* config/ia64/ia64.c (ia64_encode_section_info): Handle the case

gcc/cppfiles.c

@@ -42,7 +42,6 @@ static struct file_name_list *actual_directory
 				PARAMS ((cpp_reader *, const char *));
 static unsigned int hash_IHASH	PARAMS ((const void *));
 static int eq_IHASH		PARAMS ((const void *, const void *));
-static int file_cleanup		PARAMS ((cpp_buffer *, cpp_reader *));
 static int find_include_file	PARAMS ((cpp_reader *, const char *,
 					struct file_name_list *,
 					IHASH **, int *));
@@ -194,24 +193,6 @@ make_IHASH (name, fname, path, hash, slot)
   return ih;
 }
 
-static int
-file_cleanup (pbuf, pfile)
-     cpp_buffer *pbuf;
-     cpp_reader *pfile;
-{
-  if (pbuf->buf)
-    free ((PTR) pbuf->buf);
-  if (pfile->system_include_depth)
-    pfile->system_include_depth--;
-  if (pfile->potential_control_macro)
-    {
-      pbuf->ihash->control_macro = pfile->potential_control_macro;
-      pfile->potential_control_macro = 0;
-    }
-  pfile->input_stack_listing_current = 0;
-  return 0;
-}
-
 /* Centralize calls to open(2) here.  This provides a hook for future
    changes which might, e.g. look for and open a precompiled version
    of the header.  It also means all the magic currently associated
@@ -639,7 +620,7 @@ _cpp_execute_include (pfile, fname, len, no_reinclude, search_start)
   if (read_include_file (pfile, fd, ihash))
     {
       if (angle_brackets)
-	pfile->system_include_depth++;   /* Decremented in file_cleanup. */
+	pfile->system_include_depth++;
     }
 }
 
@@ -771,7 +752,6 @@ read_include_file (pfile, fd, ihash)
       fp->system_header_p = ihash->foundhere->sysp;
   fp->lineno = 1;
   fp->line_base = fp->buf;
-  fp->cleanup = file_cleanup;
 
   /* The ->actual_dir field is only used when ignore_srcdir is not in effect;
      see do_include */

gcc/cpphash.c

@@ -113,7 +113,6 @@ static int dump_hash_helper	  PARAMS ((void **, void *));
 static void push_macro_expansion PARAMS ((cpp_reader *, const U_CHAR *,
 					  int, HASHNODE *));
 static int unsafe_chars		 PARAMS ((cpp_reader *, int, int));
-static int macro_cleanup	 PARAMS ((cpp_buffer *, cpp_reader *));
 static enum cpp_ttype macarg	 PARAMS ((cpp_reader *, int));
 static void special_symbol	 PARAMS ((cpp_reader *, HASHNODE *));
 static int compare_defs		 PARAMS ((cpp_reader *,
@@ -332,22 +331,6 @@ _cpp_free_definition (h)
   h->value.cpval = NULL;
 }
 
-static int
-macro_cleanup (pbuf, pfile)
-     cpp_buffer *pbuf;
-     cpp_reader *pfile ATTRIBUTE_UNUSED;
-{
-  HASHNODE *m = pbuf->macro;
-  
-  m->disabled = 0;
-  if ((m->type == T_FMACRO && pbuf->buf != m->value.fdefn->expansion)
-      || m->type == T_SPECLINE || m->type == T_FILE
-      || m->type == T_BASE_FILE || m->type == T_INCLUDE_LEVEL
-      || m->type == T_STDC)
-    free ((PTR) pbuf->buf);
-  return 0;
-}
-
 /* Create pat nodes.  */
 
 static void
@@ -485,7 +468,6 @@ collect_objlike_expansion (pfile, list)
     {
       switch (list->tokens[i].type)
 	{
-	case CPP_POP:
 	case CPP_EOF:
 	  cpp_ice (pfile, "EOF in collect_expansion");
 	  /* fall through */
@@ -576,7 +558,6 @@ collect_funlike_expansion (pfile, list, arglist, replacement)
       len = list->tokens[i].val.name.len;
       switch (token)
 	{
-	case CPP_POP:
 	case CPP_EOF:
 	  cpp_ice (pfile, "EOF in collect_expansion");
 	  /* fall through */
@@ -1034,14 +1015,9 @@ macarg (pfile, rest_args)
       switch (token)
 	{
 	case CPP_EOF:
+	  /* We've hit end of file; this is an error.
+	     Caller will report it.  */
 	  return token;
-	case CPP_POP:
-	  /* If we've hit end of file, it's an error (reported by caller).
-	     Ditto if it's the end of cpp_expand_to_buffer text.
-	     If we've hit end of macro, just continue.  */
-	  if (!CPP_IS_MACRO_BUFFER (CPP_BUFFER (pfile)))
-	    return token;
-	  break;
 	case CPP_OPEN_PAREN:
 	  paren++;
 	  break;
@@ -1361,7 +1337,7 @@ scan_arguments (pfile, defn, args, name)
 	}
       else
 	token = macarg (pfile, 0);
-      if (token == CPP_EOF || token == CPP_POP)
+      if (token == CPP_EOF)
 	cpp_error_with_line (pfile, start_line, start_column,
 			     "unterminated macro call");
       i++;
@@ -1663,6 +1639,9 @@ funlike_macroexpand (pfile, hp, args)
   /* Now put the expansion on the input stack
      so our caller will commence reading from it.  */
   push_macro_expansion (pfile, xbuf, totlen, hp);
+
+  /* Overload buffer->mapped to indicate that xbuf needs to be freed.  */
+  CPP_BUFFER (pfile)->mapped = 1;
 }
 
 /* Return 1 iff a token ending in C1 followed directly by a token C2
@@ -1771,7 +1750,6 @@ push_macro_expansion (pfile, xbuf, len, hp)
     return;
   if (advance_cur)
     mbuf->cur += 2;
-  mbuf->cleanup = macro_cleanup;
   mbuf->macro = hp;
   mbuf->has_escapes = 1;
 

gcc/cpphash.h

@@ -253,7 +253,7 @@ extern void _cpp_scan_line		PARAMS ((cpp_reader *, cpp_toklist *));
 
 /* In cpplib.c */
 extern int _cpp_handle_directive	PARAMS ((cpp_reader *));
-extern void _cpp_handle_eof		PARAMS ((cpp_reader *));
+extern void _cpp_unwind_if_stack	PARAMS ((cpp_reader *, cpp_buffer *));
 extern void _cpp_check_directive        PARAMS((cpp_toklist *, cpp_token *));
 
 #endif

gcc/cpplex.c

@@ -45,7 +45,6 @@ static int copy_comment		PARAMS ((cpp_reader *, int));
 static void skip_string		PARAMS ((cpp_reader *, int));
 static void parse_string	PARAMS ((cpp_reader *, int));
 static U_CHAR *find_position	PARAMS ((U_CHAR *, U_CHAR *, unsigned long *));
-static int null_cleanup		PARAMS ((cpp_buffer *, cpp_reader *));
 static void null_warning        PARAMS ((cpp_reader *, unsigned int));
 
 static void safe_fwrite		PARAMS ((cpp_reader *, const U_CHAR *,
@@ -77,14 +76,6 @@ _cpp_grow_token_buffer (pfile, n)
   CPP_SET_WRITTEN (pfile, old_written);
 }
 
-static int
-null_cleanup (pbuf, pfile)
-     cpp_buffer *pbuf ATTRIBUTE_UNUSED;
-     cpp_reader *pfile ATTRIBUTE_UNUSED;
-{
-  return 0;
-}
-
 /* Allocate a new cpp_buffer for PFILE, and push it on the input buffer stack.
    If BUFFER != NULL, then use the LENGTH characters in BUFFER
    as the new input buffer.
@@ -107,7 +98,6 @@ cpp_push_buffer (pfile, buffer, length)
   new = (cpp_buffer *) xcalloc (1, sizeof (cpp_buffer));
 
   new->if_stack = pfile->if_stack;
-  new->cleanup = null_cleanup;
   new->buf = new->cur = buffer;
   new->rlimit = buffer + length;
   new->prev = buf;
@@ -125,7 +115,32 @@ cpp_pop_buffer (pfile)
   cpp_buffer *buf = CPP_BUFFER (pfile);
   if (ACTIVE_MARK_P (pfile))
     cpp_ice (pfile, "mark active in cpp_pop_buffer");
-  (*buf->cleanup) (buf, pfile);
+
+  if (buf->ihash)
+    {
+      _cpp_unwind_if_stack (pfile, buf);
+      if (buf->buf)
+	free ((PTR) buf->buf);
+      if (pfile->system_include_depth)
+	pfile->system_include_depth--;
+      if (pfile->potential_control_macro)
+	{
+	  buf->ihash->control_macro = pfile->potential_control_macro;
+	  pfile->potential_control_macro = 0;
+	}
+      pfile->input_stack_listing_current = 0;
+    }
+  else if (buf->macro)
+    {
+      HASHNODE *m = buf->macro;
+  
+      m->disabled = 0;
+      if ((m->type == T_FMACRO && buf->mapped)
+	  || m->type == T_SPECLINE || m->type == T_FILE
+	  || m->type == T_BASE_FILE || m->type == T_INCLUDE_LEVEL
+	  || m->type == T_STDC)
+	free ((PTR) buf->buf);
+    }
   CPP_BUFFER (pfile) = CPP_PREV_BUFFER (buf);
   free (buf);
   pfile->buffer_stack_depth--;
@@ -321,7 +336,7 @@ _cpp_expand_to_buffer (pfile, buf, length)
      const U_CHAR *buf;
      int length;
 {
-  cpp_buffer *ip;
+  cpp_buffer *stop;
   enum cpp_ttype token;
   U_CHAR *buf1;
 
@@ -338,33 +353,27 @@ _cpp_expand_to_buffer (pfile, buf, length)
   memcpy (buf1, buf, length);
 
   /* Set up the input on the input stack.  */
-  ip = cpp_push_buffer (pfile, buf1, length);
-  if (ip == NULL)
+  stop = CPP_BUFFER (pfile);
+  if (cpp_push_buffer (pfile, buf1, length) == NULL)
     return;
-  ip->has_escapes = 1;
+  CPP_BUFFER (pfile)->has_escapes = 1;
 
   /* Scan the input, create the output.  */
   for (;;)
     {
       token = cpp_get_token (pfile);
-      if (token == CPP_EOF)
+      if (token == CPP_EOF && CPP_BUFFER (pfile) == stop)
 	break;
-      if (token == CPP_POP && CPP_BUFFER (pfile) == ip)
-	{
-	  cpp_pop_buffer (pfile);
-	  break;
-	}
     }
 }
 
-/* Scan until CPP_BUFFER (PFILE) is exhausted, discarding output.
-   Then pop the buffer.  */
+/* Scan until CPP_BUFFER (PFILE) is exhausted, discarding output.  */
 
 void
 cpp_scan_buffer_nooutput (pfile)
      cpp_reader *pfile;
 {
-  cpp_buffer *buffer = CPP_BUFFER (pfile);
+  cpp_buffer *stop = CPP_PREV_BUFFER (CPP_BUFFER (pfile));
   enum cpp_ttype token;
   unsigned int old_written = CPP_WRITTEN (pfile);
   /* In no-output mode, we can ignore everything but directives.  */
@@ -373,45 +382,33 @@ cpp_scan_buffer_nooutput (pfile)
       if (! pfile->only_seen_white)
 	_cpp_skip_rest_of_line (pfile);
       token = cpp_get_token (pfile);
-      if (token == CPP_EOF)
+      if (token == CPP_EOF && CPP_BUFFER (pfile) == stop)
 	break;
-      if (token == CPP_POP && CPP_BUFFER (pfile) == buffer)
-	{
-	  cpp_pop_buffer (pfile);
-	  break;
-	}
     }
   CPP_SET_WRITTEN (pfile, old_written);
 }
 
-/* Scan until CPP_BUFFER (pfile) is exhausted, writing output to PRINT.
-   Then pop the buffer.  */
+/* Scan until CPP_BUFFER (pfile) is exhausted, writing output to PRINT.  */
 
 void
 cpp_scan_buffer (pfile, print)
      cpp_reader *pfile;
      cpp_printer *print;
 {
-  cpp_buffer *buffer = CPP_BUFFER (pfile);
+  cpp_buffer *stop = CPP_PREV_BUFFER (CPP_BUFFER (pfile));
   enum cpp_ttype token;
 
   for (;;)
     {
       token = cpp_get_token (pfile);
-      if ((token == CPP_POP && !CPP_IS_MACRO_BUFFER (CPP_BUFFER (pfile)))
-	  || token == CPP_EOF || token == CPP_VSPACE
+      if (token == CPP_EOF || token == CPP_VSPACE
 	  /* XXX Temporary kluge - force flush after #include only */
 	  || (token == CPP_DIRECTIVE
 	      && CPP_BUFFER (pfile)->nominal_fname != print->last_fname))
 	{
 	  cpp_output_tokens (pfile, print);
-	  if (token == CPP_EOF)
+	  if (token == CPP_EOF && CPP_BUFFER (pfile) == stop)
 	    return;
-	  if (token == CPP_POP && CPP_BUFFER (pfile) == buffer)
-	    {
-	      cpp_pop_buffer (pfile);
-	      return;
-	    }
 	}
     }
 }
@@ -1611,21 +1608,13 @@ cpp_get_token (pfile)
     case CPP_EOF:
       if (CPP_BUFFER (pfile) == NULL)
 	return CPP_EOF;
-      if (CPP_BUFFER (pfile)->manual_pop)
-	/* If we've been reading from redirected input, the
-	   frontend will pop the buffer.  */
-	return CPP_EOF;
-
-      if (CPP_BUFFER (pfile)->seen_eof)
+      if (CPP_IS_MACRO_BUFFER (CPP_BUFFER (pfile)))
 	{
 	  cpp_pop_buffer (pfile);
 	  goto get_next;
 	}
-      else
-	{
-	  _cpp_handle_eof (pfile);
-	  return CPP_POP;
-	}
+      cpp_pop_buffer (pfile);
+      return CPP_EOF;
     }
 }
 
@@ -1646,8 +1635,7 @@ cpp_get_non_space_token (pfile)
 }
 
 /* Like cpp_get_token, except that it does not execute directives,
-   does not consume vertical space, discards horizontal space, and
-   automatically pops off macro buffers.  */
+   does not consume vertical space, and discards horizontal space.  */
 enum cpp_ttype
 _cpp_get_directive_token (pfile)
      cpp_reader *pfile;

gcc/cpplib.c

@@ -215,8 +215,8 @@ _cpp_handle_directive (pfile)
 	return 0;
 
       if (CPP_PEDANTIC (pfile)
-	  && ! CPP_OPTION (pfile, preprocessed)
-	  && ! CPP_BUFFER (pfile)->manual_pop)
+	  && CPP_BUFFER (pfile)->ihash
+	  && ! CPP_OPTION (pfile, preprocessed))
 	cpp_pedwarn (pfile, "# followed by integer");
       do_line (pfile);
       return 1;
@@ -1345,14 +1345,17 @@ skip_if_group (pfile)
   pfile->no_macro_expand++;
   for (;;)
     {
-      /* We are at the end of a line.  Only cpp_get_token knows how to
-	 advance the line number correctly.  */
-      token = cpp_get_token (pfile);
-      if (token == CPP_POP)
+      /* We are at the end of a line.
+	 XXX Serious layering violation here.  */
+      int c = CPP_BUF_PEEK (CPP_BUFFER (pfile));
+      if (c == EOF)
 	break;  /* Caller will issue error.  */
-      else if (token != CPP_VSPACE)
-	cpp_ice (pfile, "cpp_get_token returned %d in skip_if_group", token);
+      else if (c != '\n')
+	cpp_ice (pfile, "character %c at end of line in skip_if_group", c);
+      CPP_BUFFER (pfile)->cur++;
+      CPP_BUMP_LINE (pfile);
       CPP_SET_WRITTEN (pfile, old_written);
+      pfile->only_seen_white = 1;
 
       token = _cpp_get_directive_token (pfile);
 
@@ -1458,15 +1461,18 @@ validate_else (pfile, directive)
   pfile->no_macro_expand--;
 }
 
+/* Called when we reach the end of a macro buffer.  Walk back up the
+   conditional stack till we reach its level at entry to this file,
+   issuing error messages.  */
 void
-_cpp_handle_eof (pfile)
+_cpp_unwind_if_stack (pfile, pbuf)
      cpp_reader *pfile;
+     cpp_buffer *pbuf;
 {
   struct if_stack *ifs, *nifs;
 
-  /* Unwind the conditional stack and generate error messages.  */
   for (ifs = pfile->if_stack;
-       ifs != CPP_BUFFER (pfile)->if_stack;
+       ifs != pbuf->if_stack;
        ifs = nifs)
     {
       cpp_error_with_line (pfile, ifs->lineno, 0,
@@ -1477,7 +1483,6 @@ _cpp_handle_eof (pfile)
       free (ifs);
     }
   pfile->if_stack = ifs;
-  CPP_BUFFER (pfile)->seen_eof = 1;
 }
 
 static int
@@ -1658,7 +1663,7 @@ cpp_undef (pfile, macro)
   memcpy (buf, macro, len);
   buf[len]     = '\n';
   buf[len + 1] = '\0';
-  if (cpp_push_buffer (pfile, buf, len + 1))
+  if (cpp_push_buffer (pfile, buf, len + 1) != NULL)
     {
       do_undef (pfile);
       cpp_pop_buffer (pfile);

gcc/cpplib.h

@@ -131,7 +131,6 @@ typedef struct cpp_name cpp_name;
   /* Obsolete - will be removed when no code uses them still.  */	\
   H(CPP_COMMENT,	0)		/* Only if output comments.  */ \
   N(CPP_HSPACE,		0)		/* Horizontal white space.  */	\
-  N(CPP_POP,		0)		/* End of buffer.  */		\
   N(CPP_DIRECTIVE,	0)		/* #define and the like */	\
   N(CPP_MACRO,		0)		/* Like a NAME, but expanded.  */
 
@@ -192,7 +191,6 @@ struct cpp_token
 #define SYNTAX_ASSERT  (1 << 9)
 
 typedef int (*directive_handler) PARAMS ((cpp_reader *));
-typedef int (*parse_cleanup_t) PARAMS ((cpp_buffer *, cpp_reader *));
 
 struct cpp_toklist
 {
@@ -238,8 +236,6 @@ struct cpp_buffer
      to record control macros. */
   struct ihash *ihash;
 
-  parse_cleanup_t cleanup;
-
   /* If the buffer is the expansion of a macro, this points to the
      macro's hash table entry.  */
   struct hashnode *macro;
@@ -254,9 +250,6 @@ struct cpp_buffer
   /* True if this is a header file included using <FILENAME>.  */
   char system_header_p;
 
-  /* True if end-of-file has already been hit once in this buffer.  */
-  char seen_eof;
-
   /* True if buffer contains escape sequences.
      Currently there are two kinds:
      "\r-" means following identifier should not be macro-expanded.
@@ -271,17 +264,15 @@ struct cpp_buffer
      from macro expansion text in collect_expansion and/or macarg.  */
   char has_escapes;
 
-  /* Used by the C++ frontend to implement redirected input (such as for
-     default argument and/or template parsing).  */
-  char manual_pop;
-
   /* True if we have already warned about C++ comments in this file.
      The warning happens only for C89 extended mode with -pedantic on,
      or for -Wtraditional, and only once per file (otherwise it would
      be far too noisy).  */
   char warned_cplusplus_comments;
 
-  /* True if this buffer's data is mmapped.  */
+  /* In a file buffer, true if this buffer's data is mmapped
+     (currently never the case).  In a macro buffer, true if this
+     buffer's data must be freed.  */
   char mapped;
 };
 

gcc/fix-header.c

@@ -658,10 +658,12 @@ read_scan_file (in_fname, argc, argv)
       && (fn = lookup_std_proto ("_filbuf", 7)) != NULL)
     {
       static char getchar_call[] = "getchar();";
-      cpp_buffer *buf
-	= cpp_push_buffer (&scan_in, getchar_call, sizeof(getchar_call) - 1);
       int old_written = CPP_WRITTEN (&scan_in);
       int seen_filbuf = 0;
+      cpp_buffer *buf = CPP_BUFFER (&scan_in);
+      if (cpp_push_buffer (&scan_in, getchar_call,
+			   sizeof(getchar_call) - 1) == NULL)
+	return;
 
       /* Scan the macro expansion of "getchar();".  */
       for (;;)
@@ -671,13 +673,8 @@ read_scan_file (in_fname, argc, argv)
 	  unsigned char *id = scan_in.token_buffer + old_written;
 	  
 	  CPP_SET_WRITTEN (&scan_in, old_written);
-	  if (token == CPP_EOF) /* Should not happen ...  */
+	  if (token == CPP_EOF && CPP_BUFFER (&scan_in) == buf)
 	    break;
-	  if (token == CPP_POP && CPP_BUFFER (&scan_in) == buf)
-	    {
-	      cpp_pop_buffer (&scan_in);
-	      break;
-	    }
 	  if (token == CPP_NAME && cpp_idcmp (id, length, "_filbuf") == 0)
 	    seen_filbuf++;
 	}

gcc/scan-decls.c

@@ -116,7 +116,12 @@ scan_decls (pfile, argc, argv)
       goto new_statement;
     }
   if (token == CPP_EOF)
-    return 0;
+    {
+      if (CPP_BUFFER (pfile) == NULL)
+	return 0;
+      else
+	goto new_statement;
+    }
   if (token == CPP_SEMICOLON)
     goto new_statement;
   if (token != CPP_NAME)
@@ -235,13 +240,15 @@ scan_decls (pfile, argc, argv)
 	  prev_id_end = CPP_WRITTEN (pfile);
 	  break;
 
-	case CPP_EOF:
-	  return 0;
-
 	case CPP_OPEN_BRACE:  case CPP_CLOSE_BRACE:  case CPP_DIRECTIVE:
 	  goto new_statement;  /* handle_statement? */
 	  
-	case CPP_HSPACE:  case CPP_VSPACE:  case CPP_COMMENT:  case CPP_POP:
+	case CPP_EOF:
+	  if (CPP_BUFFER (pfile) == NULL)
+	    return 0;
+	  /* else fall through */
+
+	case CPP_HSPACE:  case CPP_VSPACE:  case CPP_COMMENT:
 	  /* Skip initial white space.  */
 	  if (start_written == 0)
 	    CPP_SET_WRITTEN (pfile, 0);