c-common.c (scan_char_table): Add 'w' to flags for all formats except 'n'.

	* c-common.c (scan_char_table): Add 'w' to flags for all formats
	except 'n'.
	(check_format_info): Set 'wide' for scanf format widths.  Warn for
	a zero scanf width.  Make the check for writing into a constant
	object at the first level of indirection; at later levels, warn if
	any type qualifiers are encountered.

testsuite:
	* gcc.dg/c90-scanf-1.c, gcc.dg/c94-scanf-1.c: New tests.

From-SVN: r35842

5 files changed, 209 insertions, 24 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 06330a4..b95fbcd 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2000-08-21  Joseph S. Myers  <jsm28@cam.ac.uk>
+
+	* c-common.c (scan_char_table): Add 'w' to flags for all formats
+	except 'n'.
+	(check_format_info): Set 'wide' for scanf format widths.  Warn for
+	a zero scanf width.  Make the check for writing into a constant
+	object at the first level of indirection; at later levels, warn if
+	any type qualifiers are encountered.
+
 Mon Aug 21 07:41:12 2000  Jeffrey A Law  (law@cygnus.com)
 
 	* reload.c (reload_inner_reg_of_subreg): New function broken out of
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 2b4b0d5..e9c84f9 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -1253,15 +1253,15 @@ static format_char_info print_char_table[] = {
 };
 
 static format_char_info scan_char_table[] = {
-  { "di",	1,	T_I,	T_SC,	T_S,	T_L,	T_LL,	T_LL,	T_SST,	T_PD,	T_IM,	"*"	},
-  { "ouxX",	1,	T_UI,	T_UC,	T_US,	T_UL,	T_ULL,	T_ULL,	T_ST,	T_UPD,	T_UIM,	"*"	},
-  { "efFgEGaA",	1,	T_F,	NULL,	NULL,	T_D,	NULL,	T_LD,	NULL,	NULL,	NULL,	"*"	},
-  { "c",	1,	T_C,	NULL,	NULL,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	"*c"	},
-  { "s",	1,	T_C,	NULL,	NULL,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	"*ac"	},
-  { "[",	1,	T_C,	NULL,	NULL,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	"*ac"	},
-  { "C",	1,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	"*"	},
-  { "S",	1,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	"*a"	},
-  { "p",	2,	T_V,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	"*"	},
+  { "di",	1,	T_I,	T_SC,	T_S,	T_L,	T_LL,	T_LL,	T_SST,	T_PD,	T_IM,	"*w"	},
+  { "ouxX",	1,	T_UI,	T_UC,	T_US,	T_UL,	T_ULL,	T_ULL,	T_ST,	T_UPD,	T_UIM,	"*w"	},
+  { "efFgEGaA",	1,	T_F,	NULL,	NULL,	T_D,	NULL,	T_LD,	NULL,	NULL,	NULL,	"*w"	},
+  { "c",	1,	T_C,	NULL,	NULL,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	"*cw"	},
+  { "s",	1,	T_C,	NULL,	NULL,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	"*acw"	},
+  { "[",	1,	T_C,	NULL,	NULL,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	"*acw"	},
+  { "C",	1,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	"*w"	},
+  { "S",	1,	T_W,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	"*aw"	},
+  { "p",	2,	T_V,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	"*w"	},
   { "n",	1,	T_I,	T_SC,	T_S,	T_L,	T_LL,	NULL,	T_SST,	T_PD,	T_IM,	""	},
   { NULL,	0,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL	}
 };
@@ -1618,6 +1618,7 @@ check_format_info (info, params)
     {
       int aflag;
       int char_type_flag = 0;
+      int writing_in_flag = 0;
       if (*format_chars == 0)
 	{
 	  if (format_chars - TREE_STRING_POINTER (format_tree) != format_length)
@@ -1642,11 +1643,19 @@ check_format_info (info, params)
       suppressed = wide = precise = FALSE;
       if (info->format_type == scanf_format_type)
 	{
+	  int non_zero_width_char = FALSE;
 	  suppressed = *format_chars == '*';
 	  if (suppressed)
 	    ++format_chars;
 	  while (ISDIGIT (*format_chars))
-	    ++format_chars;
+	    {
+	      wide = TRUE;
+	      if (*format_chars != '0')
+		non_zero_width_char = TRUE;
+	      ++format_chars;
+	    }
+	  if (wide && !non_zero_width_char)
+	    warning ("zero width in scanf format");
 	}
       else if (info->format_type == strftime_format_type)
         {
@@ -2047,6 +2056,12 @@ check_format_info (info, params)
 
       STRIP_NOPS (cur_param);
 
+      if ((info->format_type == scanf_format_type
+	   || (info->format_type == printf_format_type
+	       && format_char == 'n'))
+	  && wanted_type != 0)
+	writing_in_flag = 1;
+
       /* Check the types of any additional pointer arguments
 	 that precede the "real" argument.  */
       for (i = 0; i < fci->pointer_count + aflag; ++i)
@@ -2060,6 +2075,33 @@ check_format_info (info, params)
 	      else
 		cur_param = 0;
 
+	      /* See if this is an attempt to write into a const type with
+		 scanf or with printf "%n".  Note: the writing in happens
+		 at the first indirection only, if for example
+		 void * const * is passed to scanf %p; passing
+		 const void ** is simply passing an incompatible type.  */
+	      if (writing_in_flag
+		  && i == 0
+		  && TREE_CODE (cur_type) != ERROR_MARK
+		  && (TYPE_READONLY (cur_type)
+		      || (cur_param != 0
+			  && (TREE_CODE_CLASS (TREE_CODE (cur_param)) == 'c'
+			      || (DECL_P (cur_param)
+				  && TREE_READONLY (cur_param))))))
+		warning ("writing into constant object (arg %d)", arg_num);
+
+	      /* If there are extra type qualifiers beyond the first
+		 indirection, then this makes the types technically
+		 incompatible.  */
+	      if (i > 0
+		  && pedantic
+		  && TREE_CODE (cur_type) != ERROR_MARK
+		  && (TYPE_READONLY (cur_type)
+		      || TYPE_VOLATILE (cur_type)
+		      || TYPE_RESTRICT (cur_type)))
+		warning ("extra type qualifiers in format argument (arg %d)",
+			 arg_num);
+
 	      continue;
 	    }
 	  if (TREE_CODE (cur_type) != ERROR_MARK)
@@ -2072,20 +2114,6 @@ check_format_info (info, params)
 	  break;
 	}
 
-      /* See if this is an attempt to write into a const type with
-	 scanf or with printf "%n".  */
-      if ((info->format_type == scanf_format_type
-	   || (info->format_type == printf_format_type
-	       && format_char == 'n'))
-	  && i == fci->pointer_count + aflag
-	  && wanted_type != 0
-	  && TREE_CODE (cur_type) != ERROR_MARK
-	  && (TYPE_READONLY (cur_type)
-	      || (cur_param != 0
-		  && (TREE_CODE_CLASS (TREE_CODE (cur_param)) == 'c'
-		      || (DECL_P (cur_param) && TREE_READONLY (cur_param))))))
-	warning ("writing into constant object (arg %d)", arg_num);
-
       /* Check whether the argument type is a character type.  This leniency
 	 only applies to certain formats, flagged with 'c'.
       */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0297b60..c94de4d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2000-08-21  Joseph S. Myers  <jsm28@cam.ac.uk>
+
+	* gcc.dg/c90-scanf-1.c, gcc.dg/c94-scanf-1.c: New tests.
+
 2000-08-21  Jakub Jelinek  <jakub@redhat.com>
 
 	* g++.old-deja/g++.other/loop2.C: New test.
diff --git a/gcc/testsuite/gcc.dg/c90-scanf-1.c b/gcc/testsuite/gcc.dg/c90-scanf-1.c
new file mode 100644
index 0000000..021316c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c90-scanf-1.c
@@ -0,0 +1,125 @@
+/* Test for scanf formats.  Formats using C90 features, including cases
+   where C90 specifies some aspect of the format to be ignored or where
+   the behaviour is undefined.
+*/
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1990 -pedantic -Wformat" } */
+
+typedef __WCHAR_TYPE__ wchar_t;
+
+__extension__ typedef long long int llong;
+__extension__ typedef unsigned long long int ullong;
+
+extern int scanf (const char *, ...);
+
+#define NULL ((void *)0)
+
+void
+foo (int *ip, unsigned int *uip, short int *hp, unsigned short int *uhp,
+     long int *lp, unsigned long int *ulp, float *fp, double *dp,
+     long double *ldp, char *s, signed char *ss, unsigned char *us,
+     void **pp, int *n, llong *llp, ullong *ullp, wchar_t *ls,
+     const int *cip, const int *cn, const char *cs, const void **ppc,
+     void *const *pcp, short int *hn, long int *ln, void *p, char **sp,
+     volatile void *ppv)
+{
+  /* See ISO/IEC 9899:1990 (E) subclause 7.9.6.2 (pages 134-138).  */
+  /* Basic sanity checks for the different components of a format.  */
+  scanf ("%d", ip);
+  scanf ("%*d");
+  scanf ("%3d", ip);
+  scanf ("%hd", hp);
+  scanf ("%3ld", lp);
+  scanf ("%*3d");
+  scanf ("%d %ld", ip, lp);
+  /* Valid and invalid %% constructions.  */
+  scanf ("%%");
+  scanf ("%*%"); /* { dg-warning "format" "bogus %%" } */
+  scanf ("%*%\n"); /* { dg-warning "format" "bogus %%" } */
+  scanf ("%4%"); /* { dg-warning "format" "bogus %%" } */
+  scanf ("%4%\n"); /* { dg-warning "format" "bogus %%" } */
+  scanf ("%h%"); /* { dg-warning "format" "bogus %%" } */
+  scanf ("%h%\n"); /* { dg-warning "format" "bogus %%" } */
+  /* Valid, invalid and silly assignment-suppression constructions.  */
+  scanf ("%*d%*i%*o%*u%*x%*X%*e%*E%*f%*g%*G%*s%*[abc]%*c%*p");
+  scanf ("%*2d%*8s%*3c");
+  scanf ("%*n"); /* { dg-warning "suppress" "suppression of %n" } */
+  scanf ("%*hd"); /* { dg-warning "together" "suppression with length" } */
+  /* Valid, invalid and silly width constructions.  */
+  scanf ("%2d%3i%4o%5u%6x%7X%8e%9E%10f%11g%12G%13s%14[abc]%15c%16p",
+	 ip, ip, uip, uip, uip, uip, fp, fp, fp, fp, fp, s, s, s, pp);
+  scanf ("%0d", ip); /* { dg-warning "width" "warning for zero width" } */
+  scanf ("%3n", n); /* { dg-warning "width" "width with %n" } */
+  /* Valid and invalid %h, %l, %L constructions.  */
+  scanf ("%hd%hi%ho%hu%hx%hX%hn", hp, hp, uhp, uhp, uhp, uhp, hn);
+  scanf ("%he", fp); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hE", fp); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hf", fp); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hg", fp); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hG", fp); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hs", s); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%h[ac]", s); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hc", s); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%hp", pp); /* { dg-warning "length character" "bad use of %h" } */
+  scanf ("%h"); /* { dg-warning "conversion lacks type" "bare %h" } */
+  scanf ("%h."); /* { dg-warning "conversion" "bogus %h" } */
+  scanf ("%ld%li%lo%lu%lx%lX%ln", lp, lp, ulp, ulp, ulp, ulp, ln);
+  scanf ("%le%lE%lf%lg%lG", dp, dp, dp, dp, dp);
+  scanf ("%lp", pp); /* { dg-warning "length character" "bad use of %l" } */
+  /* These next three formats were added in C94.  */
+  scanf ("%ls", ls); /* { dg-warning "length character|C" "bad use of %l" } */
+  scanf ("%l[ac]", ls); /* { dg-warning "length character|C" "bad use of %l" } */
+  scanf ("%lc", ls); /* { dg-warning "length character|C" "bad use of %l" } */
+  scanf ("%Le%LE%Lf%Lg%LG", ldp, ldp, ldp, ldp, ldp);
+  scanf ("%Ld", llp); /* { dg-warning "does not support" "bad use of %L" } */
+  scanf ("%Li", llp); /* { dg-warning "does not support" "bad use of %L" } */
+  scanf ("%Lo", ullp); /* { dg-warning "does not support" "bad use of %L" } */
+  scanf ("%Lu", ullp); /* { dg-warning "does not support" "bad use of %L" } */
+  scanf ("%Lx", ullp); /* { dg-warning "does not support" "bad use of %L" } */
+  scanf ("%LX", ullp); /* { dg-warning "does not support" "bad use of %L" } */
+  scanf ("%Ls", s); /* { dg-warning "length character" "bad use of %L" } */
+  scanf ("%L[ac]", s); /* { dg-warning "length character" "bad use of %L" } */
+  scanf ("%Lc", s); /* { dg-warning "length character" "bad use of %L" } */
+  scanf ("%Lp", pp); /* { dg-warning "length character" "bad use of %L" } */
+  scanf ("%Ln", n); /* { dg-warning "length character" "bad use of %L" } */
+  /* Valid uses of each bare conversion.  */
+  scanf ("%d%i%o%u%x%X%e%E%f%g%G%s%[abc]%c%p%n%%", ip, ip, uip, uip, uip,
+	 uip, fp, fp, fp, fp, fp, s, s, s, pp, n);
+  /* Allow other character pointers with %s, %c, %[].  */
+  scanf ("%2s%3s%4c%5c%6[abc]%7[abc]", ss, us, ss, us, ss, us);
+  /* Further tests for %[].  */
+  scanf ("%[%d]%d", s, ip);
+  scanf ("%[^%d]%d", s, ip);
+  scanf ("%[]%d]%d", s, ip);
+  scanf ("%[^]%d]%d", s, ip);
+  scanf ("%[%d]%d", s, ip);
+  scanf ("%[]abcd", s); /* { dg-warning "no closing" "incomplete scanset" } */
+  /* Various tests of bad argument types.  Some of these are only pedantic
+     warnings.
+  */
+  scanf ("%d", lp); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%d", uip); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%d", pp); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%p", ppc); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%p", ppv); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%s", n); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%s", p); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%p", p); /* { dg-warning "format" "bad argument types" } */
+  scanf ("%p", sp); /* { dg-warning "format" "bad argument types" } */
+  /* Tests for writing into constant values.  */
+  scanf ("%d", cip); /* { dg-warning "constant" "%d writing into const" } */
+  scanf ("%n", cn); /* { dg-warning "constant" "%n writing into const" } */
+  scanf ("%s", cs); /* { dg-warning "constant" "%s writing into const" } */
+  scanf ("%p", pcp); /* { dg-warning "constant" "%p writing into const" } */
+  /* Wrong number of arguments.  */
+  scanf ("%d%d", ip); /* { dg-warning "arguments" "wrong number of args" } */
+  scanf ("%d", ip, ip); /* { dg-warning "arguments" "wrong number of args" } */
+  /* Miscellaneous bogus constructions.  */
+  scanf (""); /* { dg-warning "zero-length" "warning for empty format" } */
+  scanf ("\0"); /* { dg-warning "embedded" "warning for embedded NUL" } */
+  scanf ("%d\0", ip); /* { dg-warning "embedded" "warning for embedded NUL" } */
+  scanf ("%d\0%d", ip, ip); /* { dg-warning "embedded|too many" "warning for embedded NUL" } */
+  scanf (NULL); /* { dg-warning "null" "null format string warning" } */
+  scanf ("%"); /* { dg-warning "trailing" "trailing % warning" } */
+}
diff --git a/gcc/testsuite/gcc.dg/c94-scanf-1.c b/gcc/testsuite/gcc.dg/c94-scanf-1.c
new file mode 100644
index 0000000..884cd28
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c94-scanf-1.c
@@ -0,0 +1,19 @@
+/* Test for scanf formats.  Changes in C94 to C90.  */
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:199409 -pedantic -Wformat" } */
+
+typedef __WCHAR_TYPE__ wchar_t;
+
+extern int scanf (const char *, ...);
+
+void
+foo (wchar_t *ls)
+{
+  /* See ISO/IEC 9899:1990 (E) subclause 7.9.6.2 (pages 134-138),
+     as amended by ISO/IEC 9899:1990/Amd.1:1995 (E) (pages 5-6).
+     We do not repeat here all the C90 format checks, but just verify
+     that %ls, %lc, %l[] are accepted without warning.
+  */
+  scanf ("%lc%ls%l[abc]", ls, ls, ls);
+}