cppfiles.c (open_include_file): If open(2) returns EMFILE or ENFILE...

	* cppfiles.c (open_include_file): If open(2) returns EMFILE or
	ENFILE, close all cached file descriptors and try again.
	(_cpp_execute_include): Keep a count of the number of times
	each header is included.
	(close_cached_fd): New function.
	* cpphash.h (struct include_file): Rename before to
	include_count; all users updated.  Make include_count and sysp
	unsigned short.
	* cppinit.c (cpp_finish): If -H, report headers that could use
	reinclude guards.
	(report_missing_guard): New function.

From-SVN: r34760

gcc/ChangeLog

+2000-06-28  Zack Weinberg  <zack@wolery.cumb.org>
+
+	* cppfiles.c (open_include_file): If open(2) returns EMFILE or
+	ENFILE, close all cached file descriptors and try again.      
+	(_cpp_execute_include): Keep a count of the number of times
+	each header is included.
+	(close_cached_fd): New function.
+	* cpphash.h (struct include_file): Rename before to
+	include_count; all users updated.  Make include_count and sysp
+	unsigned short.
+	* cppinit.c (cpp_finish): If -H, report headers that could use
+	reinclude guards.
+	(report_missing_guard): New function.
+
 Wed Jun 28 14:46:58 MET DST 2000  Jan Hubicka  <jh@suse.cz>
 
 	* i386.md (prologue_set_got): Set length_immediate field.

gcc/cppfiles.c

@@ -60,6 +60,7 @@ static ssize_t read_with_read	PARAMS ((cpp_buffer *, int, ssize_t));
 static ssize_t read_file	PARAMS ((cpp_buffer *, int, ssize_t));
 
 static void destroy_include_file_node	PARAMS ((splay_tree_value));
+static int close_cached_fd	PARAMS ((splay_tree_node, void *));
 
 #if 0
 static void hack_vms_include_specification PARAMS ((char *));
@@ -87,6 +88,20 @@ destroy_include_file_node (v)
     }
 }
 
+static int
+close_cached_fd (n, dummy)
+     splay_tree_node n;
+     void *dummy ATTRIBUTE_UNUSED;
+{
+  struct include_file *f = (struct include_file *)n->value;
+  if (f && f->fd != -1)
+    {
+      close (f->fd);
+      f->fd = -1;
+    }
+  return 0;
+}
+
 void
 _cpp_init_include_table (pfile)
      cpp_reader *pfile;
@@ -153,6 +168,8 @@ open_include_file (pfile, filename)
      ourselves.
 
      Special case: the empty string is translated to stdin.  */
+ retry:
+
   if (filename[0] == '\0')
     fd = 0;
   else
@@ -167,6 +184,21 @@ open_include_file (pfile, filename)
 		     filename);
 	}
 #endif
+      if (0
+#ifdef EMFILE
+	  || errno == EMFILE
+#endif
+#ifdef ENFILE
+	  || errno == ENFILE
+#endif
+	  )
+	{
+	  /* Too many files open.  Close all cached file descriptors and
+	     try again.  */
+	  splay_tree_foreach (pfile->all_include_files, close_cached_fd, 0);
+	  goto retry;
+	}
+
       /* Nonexistent or inaccessible file.  Create a negative node for it.  */
       if (nd)
 	{
@@ -185,7 +217,7 @@ open_include_file (pfile, filename)
     {
       file = xnew (struct include_file);
       file->cmacro = 0;
-      file->before = 0;
+      file->include_count = 0;
       file->sysp = 0;
       file->foundhere = 0;
       file->name = xstrdup (filename);
@@ -367,9 +399,9 @@ _cpp_execute_include (pfile, f, len, no_reinclude, search_start)
 	return;
 
       /* For -M, add the file to the dependencies on its first inclusion. */
-      if (!inc->before && PRINT_THIS_DEP (pfile, angle_brackets))
+      if (!inc->include_count && PRINT_THIS_DEP (pfile, angle_brackets))
 	deps_add_dep (pfile->deps, inc->name);
-      inc->before = 1;
+      inc->include_count++;
 
       /* Handle -H option.  */
       if (CPP_OPTION (pfile, print_include_names))

gcc/cpphash.h

@@ -62,8 +62,8 @@ struct include_file
 				/* location in search path where file was
 				   found, for #include_next */
   int fd;			/* file descriptor possibly open on file */
-  unsigned char before;		/* file has been included before */
-  unsigned char sysp;		/* file is a system header */
+  unsigned short include_count;	/* number of times file has been read */
+  unsigned short sysp;		/* file is a system header */
 };
 
 /* The cmacro works like this: If it's NULL, the file is to be

gcc/cppinit.c

@@ -227,6 +227,7 @@ static int opt_comp			PARAMS ((const void *, const void *));
 #endif
 static int parse_option			PARAMS ((const char *));
 static int handle_option		PARAMS ((cpp_reader *, int, char **));
+static int report_missing_guard		PARAMS ((splay_tree_node, void *));
 
 /* Fourth argument to append_include_chain: chain to use */
 enum { QUOTE = 0, BRACKET, SYSTEM, AFTER };
@@ -1003,6 +1004,27 @@ cpp_start_read (pfile, print, fname)
   return 1;
 }
 
+static int
+report_missing_guard (n, b)
+     splay_tree_node n;
+     void *b;
+{
+  struct include_file *f = (struct include_file *) n->value;
+  int *bannerp = (int *)b;
+
+  if (f && f->cmacro == 0 && f->include_count == 1)
+    {
+      if (*bannerp == 0)
+	{
+	  fputs (_("Multiple include guards may be useful for:\n"), stderr);
+	  *bannerp = 1;
+	}
+      fputs (f->name, stderr);
+      putc ('\n', stderr);
+    }
+  return 0;
+}
+
 /* This is called at the end of preprocessing.  It pops the
    last buffer and writes dependency output.  It should also
    clear macro definitions, such that you could call cpp_start_read
@@ -1055,6 +1077,14 @@ cpp_finish (pfile, print)
       if (ferror (print->outf) || fclose (print->outf))
 	cpp_notice_from_errno (pfile, CPP_OPTION (pfile, out_fname));
     }
+
+  /* Report on headers that could use multiple include guards.  */
+  if (CPP_OPTION (pfile, print_include_names))
+    {
+      int banner = 0;
+      splay_tree_foreach (pfile->all_include_files, report_missing_guard,
+			  (void *) &banner);
+    }
 }
 
 static void