tradcpp: Fix PR 3824

[Neil Booth <neil at daikokuya dot demon dot co dot uk>]

Numbers are by default signed in traditional C.

Also, I've filled out some comments about line maps.

I'll commit this once it bootstraps.

Neil.

	PR preprocessor/3824
	* line-map.c: Update comments.
	* line-map.h: Update comments.
	* tradcif.y: Don't consider large numbers unsigned.
	* gcc.dg/cpp/tr-sign.c: New testcase.

Index: line-map.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/line-map.c,v
retrieving revision 1.1
diff -u -p -r1.1 line-map.c
--- line-map.c	2001/08/02 23:03:30	1.1
+++ line-map.c	2001/08/05 18:14:07
@@ -93,7 +93,10 @@ add_line_map (set, reason, from_line, to
   return map;
 }
 
-/* Translate a logical line number into a (source file, line) pair.  */
+/* Given a logical line, returns the map from which the corresponding
+   (source file, line) pair can be deduced.  Since the set is built
+   chronologically, the logical lines are monotonic increasing, and so
+   the list is sorted and we can use a binary search.  */
 
 struct line_map *
 lookup_line (set, line)
Index: line-map.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/line-map.h,v
retrieving revision 1.3
diff -u -p -r1.3 line-map.h
--- line-map.h	2001/08/05 17:31:23	1.3
+++ line-map.h	2001/08/05 18:14:09
@@ -44,7 +44,11 @@ struct line_maps
   unsigned int used;
 };
 
-/* Reason for adding a line change with add_line_map ().  */
+/* Reason for adding a line change with add_line_map ().  LC_ENTER is
+   when including a new file, e.g. a #include directive in C.
+   LC_LEAVE is when reaching a file's end.  LC_RENAME is when a file
+   name or line number changes for neither of the above reasons
+   (e.g. a #line directive in C).  */
 enum lc_reason {LC_ENTER = 0, LC_LEAVE, LC_RENAME};
 
 /* Initialize a line map set.  */
@@ -56,7 +60,7 @@ extern void free_line_maps
   PARAMS ((struct line_maps *));
 
 /* Add a mapping of logical source line to physical source file and
-   line number.  Ther text pointed to by TO_FILE must have a lifetime
+   line number.  The text pointed to by TO_FILE must have a lifetime
    at least as long as the final call to lookup_line ().
 
    FROM_LINE should be monotonic increasing across calls to this
@@ -80,7 +84,8 @@ extern struct line_map *lookup_line
 /* Non-zero if the map is at the bottom of the include stack.  */
 #define MAIN_FILE_P(MAP) ((MAP)->included_from < 0)
 
-/* The current line map.  */
+/* The current line map.  Saves a call to lookup_line if the caller is
+   sure he is in the scope of the current map.  */
 #define CURRENT_LINE_MAP(MAPS) ((MAPS)->maps + (MAPS)->used - 1)
 
 #endif /* !GCC_LINE_MAP_H  */
Index: tradcif.y
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tradcif.y,v
retrieving revision 1.8
diff -u -p -r1.8 tradcif.y
--- tradcif.y	2001/03/28 19:24:11	1.8
+++ tradcif.y	2001/08/05 18:14:10
@@ -231,6 +231,8 @@ parse_number (olen)
       return ERROR;
     }
 
+  /* Traditionally, all numbers are signed.  However, we make it
+     unsigned if requested with a suffix.  */
   yylval.integer.unsignedp = 0;
 
   if (len >= 3 && (!strncmp (p, "0x", 2) || !strncmp (p, "0X", 2))) {
@@ -276,10 +278,6 @@ parse_number (olen)
     yyerror ("Invalid number in #if expression");
     return ERROR;
   }
-
-  /* If too big to be signed, consider it unsigned.  */
-  if (n < 0)
-    yylval.integer.unsignedp = 1;
 
   lexptr = p;
   yylval.integer.value = n;
Index: testsuite/gcc.dg/cpp/tr-sign.c
===================================================================
RCS file: tr-sign.c
diff -N tr-sign.c
--- /dev/null	Tue May  5 13:32:27 1998
+++ tr-sign.c	Sun Aug  5 11:14:29 2001
@@ -0,0 +1,18 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc.  */
+
+/* { dg-do preprocess { target i?86-*-* } } */
+
+/* { dg-options "-traditional" } */
+
+/* Tests that traditional numbers are signed, unless otherwise
+   specified.  This test assumes a 32 bit target.
+
+   Neil Booth, 1 Dec 2000.  Inspired by PR 3824.  */
+
+#if 0xffffffff >= 0
+# error	0xffffffff	/* { dg-bogus "0xffffffff" "0xffffffff positive" } */
+#endif
+
+#if 0xffffffffU <= 0
+# error	0xffffffffU	/* { dg-bogus "0xffffffffU" "0xffffffffU negative" } */
+#endif