Warning from cpp on macro argument stringification is missing

Kaveh R. Ghazi ghazi@caip.rutgers.edu
Fri Sep 8 15:28:00 GMT 2000


Thanks for the feedback!

This one should be ready to install.  Bootstrapped on solaris2.7, no
regressions.

		--Kaveh




2000-09-08  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>

	* cppmacro.c (check_trad_stringification): New function.
	(save_expansion): If -Wtraditional, warn about stringification of
	macro arguments.

testsuite:
	* gcc.dg/cpp/tr-warn6.c: New test.

diff -rup orig/egcs-CVS20000906/gcc/cppmacro.c egcs-CVS20000906/gcc/cppmacro.c
--- orig/egcs-CVS20000906/gcc/cppmacro.c	Fri Aug 18 09:48:44 2000
+++ egcs-CVS20000906/gcc/cppmacro.c	Fri Sep  8 12:17:54 2000
@@ -52,6 +52,9 @@ static const cpp_toklist * save_expansio
 static unsigned int find_param PARAMS ((const cpp_token *,
  					const cpp_token *));
 static cpp_toklist * alloc_macro PARAMS ((cpp_reader *, struct macro_info *));
+static void check_trad_stringification PARAMS ((cpp_reader *,
+						const struct macro_info *,
+						const cpp_string *));
 
 /* These are all the tokens that can have something pasted after them.
    Comma is included in the list only to support the GNU varargs extension
@@ -502,6 +505,12 @@ save_expansion (pfile, info)
 	    continue;
 	  break;
 
+	case CPP_STRING:
+	case CPP_CHAR:
+	  if (CPP_WTRADITIONAL (pfile) && list->paramc > 0)
+	    check_trad_stringification (pfile, info, &token->val.str);
+	  break;
+	  
 	default:
 	  break;
 	}
@@ -617,4 +626,47 @@ dump_macro_args (fp, list)
       param += len + 1;
     }
   putc (')', fp);
+}
+
+/* Warn if a token in `string' matches one of the function macro
+   arguments in `info'.  This function assumes that the macro is a
+   function macro and not an object macro.  */
+static void
+check_trad_stringification (pfile, info, string)
+     cpp_reader *pfile;
+     const struct macro_info *info;
+     const cpp_string *string;
+{
+  const U_CHAR *p, *q, *limit = string->text + string->len;
+  
+  /* Loop over the string.  */
+  for (p = string->text; p < limit; p = q)
+    {
+      const cpp_token *token;
+
+      /* Find the start of an identifier.  */
+      while (!is_idstart (*p) && p < limit) p++;
+
+      /* Find the end of the identifier.  */
+      q = p;
+      while (is_idchar (*q) && q < limit) q++;
+     
+      /* Loop over the function macro arguments to see if the
+	 identifier inside the string matches one of them.  */
+      for (token = info->first_param; token < info->first; token++)
+        {
+	  /* Skip the commas in between the arguments.  */
+	  if (token->type != CPP_NAME)
+	    continue;
+
+	  if (token->val.node->length == (q - p)
+	      && !memcmp (p, token->val.node->name, (q - p)))
+	    {
+	      cpp_warning (pfile,
+			   "macro arg \"%.*s\" would be stringified with -traditional.",
+			   (int) (q - p), p);
+	      break;
+	    }
+	}
+    }
 }
diff -rup orig/egcs-CVS20000906/gcc/testsuite/gcc.dg/cpp/tr-warn6.c egcs-CVS20000906/gcc/testsuite/gcc.dg/cpp/tr-warn6.c
--- orig/egcs-CVS20000906/gcc/testsuite/gcc.dg/cpp/tr-warn6.c	Fri Sep  8 13:16:44 2000
+++ egcs-CVS20000906/gcc/testsuite/gcc.dg/cpp/tr-warn6.c	Fri Sep  8 12:29:11 2000
@@ -0,0 +1,27 @@
+/* Test for -Wtraditional warnings for stringification of macro args.
+   Note, gcc should omit these warnings in system header files.
+   By Kaveh R. Ghazi <ghazi@caip.rutgers.edu> 9/8/2000.  */
+/* { dg-do preprocess } */
+/* { dg-options "-Wtraditional -fno-show-column" } */
+
+#define foo1(h) sdf "h3" fds "h" /* { dg-warning "macro arg \"h\" would be stringified" "traditional stringification" } */
+#define foo2(h2) sdf "h2" fds "h3" /* { dg-warning "macro arg \"h2\" would be stringified" "traditional stringification" } */
+#define foo3(h3) sdf "h2" fds "h3" /* { dg-warning "macro arg \"h3\" would be stringified" "traditional stringification" } */
+#define foo4(h) sdf 'h3' fds 'h' /* { dg-warning "macro arg \"h\" would be stringified" "traditional stringification" } */
+#define foo5(h2) sdf 'h2' fds 'h3' /* { dg-warning "macro arg \"h2\" would be stringified" "traditional stringification" } */
+#define foo6(h3) sdf 'h2' fds 'h3' /* { dg-warning "macro arg \"h3\" would be stringified" "traditional stringification" } */
+#define foo7(AA, hello, world, EEE) sdf "A B hello C,world,DhelloE F" fds EEE /* { dg-warning "macro arg \"hello\" would be stringified" "traditional stringification" } */
+
+/* Catch the second warning from the above line.  */
+/* { dg-warning "macro arg \"world\" would be stringified" "traditional stringification" { target *-*-* } 13 } */
+
+#line 19 "sys-header.h" 3
+/* We are in system headers now, no -Wtraditional warnings should issue.  */
+
+#define bar1(h) sdf "h3" fds "h"
+#define bar2(h2) sdf "h2" fds "h3"
+#define bar3(h3) sdf "h2" fds "h3"
+#define bar4(h) sdf 'h3' fds 'h'
+#define bar5(h2) sdf 'h2' fds 'h3'
+#define bar6(h3) sdf 'h2' fds 'h3'
+#define bar7(AA, hello, world, EEE) sdf "A B hello C,world,DhelloE F" fds EEE


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