Patch for middle-end/PR79538

missing -Wformat-overflow with %s and non-member array arguments 

-Wformat-overflow uses the routine "get_range_strlen" to decide the 
maximum string length, however, currently "get_range_strlen" misses 
the handling of non-member arrays.

Adding the handling of non-member array resolves the issue.
Adding test case pr79538.c into gcc.dg.

During gcc bootstrap, 2 source files (c-family/c-cppbuiltin.c, 
fortran/class.c) were detected new warnings by -Wformat-overflow
due to the new handling of non-member array in "get_range_strlen".
in order to avoid these new warnings and continue with bootstrap,
updating these 2 files to avoid the warnings.

in c-family/c-cppbuiltin.c, the warning is following:

../../latest_gcc_2/gcc/c-family/c-cppbuiltin.c:1627:15: note: 
‘sprintf’ output 2 or more bytes (assuming 257) into a destination 
of size 256
       sprintf (buf1, "%s=%s", macro, buf2);
       ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
in the above, buf1 and buf2 are declared as:
char buf1[256], buf2[256];

i.e, buf1 and buf2 have same size. adjusting the size of buf1 and 
buf2 resolves the warning. 

fortran/class.c has the similar issue as above. Instead of adjusting
size of the buffers, replacing sprintf with xasprintf is a better 
solution for these cases.

From-SVN: r255654

gcc/ChangeLog

+2017-12-14  Qing Zhao  <qing.zhao@oracle.com>
+
+	PR middle_end/79538
+	* gimple-fold.c (get_range_strlen): Add the handling of non-member 
+	array.
+
 2017-12-14  David Malcolm  <dmalcolm@redhat.com>
 
 	PR tree-optimization/83312

gcc/c-family/ChangeLog

+2017-12-14  Qing Zhao  <qing.zhao@oracle.com>
+
+	PR middle_end/79538 
+	* c-cppbuiltin.c (builtin_define_with_hex_fp_value):
+	Adjust the size of buf1 and buf2, add a new buf to avoid
+	format-overflow warning.
+
 2017-12-12  Alexandre Oliva <aoliva@redhat.com>
 
 	* c-semantics.c (pop_stmt_list): Move begin stmt marker into

gcc/c-family/c-cppbuiltin.c

@@ -1613,7 +1613,7 @@ builtin_define_with_hex_fp_value (const char *macro,
 				  const char *fp_cast)
 {
   REAL_VALUE_TYPE real;
-  char dec_str[64], buf1[256], buf2[256];
+  char dec_str[64], buf[256], buf1[128], buf2[64];
 
   /* This is very expensive, so if possible expand them lazily.  */
   if (lazy_hex_fp_value_count < 12
@@ -1656,11 +1656,11 @@ builtin_define_with_hex_fp_value (const char *macro,
 
   /* Assemble the macro in the following fashion
      macro = fp_cast [dec_str fp_suffix] */
-  sprintf (buf1, "%s%s", dec_str, fp_suffix);
-  sprintf (buf2, fp_cast, buf1);
-  sprintf (buf1, "%s=%s", macro, buf2);
+  sprintf (buf2, "%s%s", dec_str, fp_suffix);
+  sprintf (buf1, fp_cast, buf2);
+  sprintf (buf, "%s=%s", macro, buf1);
 
-  cpp_define (parse_in, buf1);
+  cpp_define (parse_in, buf);
 }
 
 /* Return a string constant for the suffix for a value of type TYPE

gcc/fortran/ChangeLog

+2017-12-14  Qing Zhao  <qing.zhao@oracle.com>
+
+	PR middle_end/79538
+	* class.c (gfc_build_class_symbol): Replace call to
+	sprintf with xasprintf to avoid format-overflow warning.
+	(generate_finalization_wrapper): Likewise.
+	(gfc_find_derived_vtab): Likewise.
+	(find_intrinsic_vtab): Likewise.
+
 2017-12-12  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	* intrinsic.texi (MAXLOC): Remove double description

gcc/fortran/class.c

@@ -602,7 +602,8 @@ bool
 gfc_build_class_symbol (gfc_typespec *ts, symbol_attribute *attr,
 			gfc_array_spec **as)
 {
-  char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
+  char tname[GFC_MAX_SYMBOL_LEN+1];
+  char *name;
   gfc_symbol *fclass;
   gfc_symbol *vtab;
   gfc_component *c;
@@ -633,17 +634,17 @@ gfc_build_class_symbol (gfc_typespec *ts, symbol_attribute *attr,
   rank = !(*as) || (*as)->rank == -1 ? GFC_MAX_DIMENSIONS : (*as)->rank;
   get_unique_hashed_string (tname, ts->u.derived);
   if ((*as) && attr->allocatable)
-    sprintf (name, "__class_%s_%d_%da", tname, rank, (*as)->corank);
+    name = xasprintf ("__class_%s_%d_%da", tname, rank, (*as)->corank);
   else if ((*as) && attr->pointer)
-    sprintf (name, "__class_%s_%d_%dp", tname, rank, (*as)->corank);
+    name = xasprintf ("__class_%s_%d_%dp", tname, rank, (*as)->corank);
   else if ((*as))
-    sprintf (name, "__class_%s_%d_%dt", tname, rank, (*as)->corank);
+    name = xasprintf ("__class_%s_%d_%dt", tname, rank, (*as)->corank);
   else if (attr->pointer)
-    sprintf (name, "__class_%s_p", tname);
+    name = xasprintf ("__class_%s_p", tname);
   else if (attr->allocatable)
-    sprintf (name, "__class_%s_a", tname);
+    name = xasprintf ("__class_%s_a", tname);
   else
-    sprintf (name, "__class_%s_t", tname);
+    name = xasprintf ("__class_%s_t", tname);
 
   if (ts->u.derived->attr.unlimited_polymorphic)
     {
@@ -738,6 +739,7 @@ gfc_build_class_symbol (gfc_typespec *ts, symbol_attribute *attr,
   ts->u.derived = fclass;
   attr->allocatable = attr->pointer = attr->dimension = attr->codimension = 0;
   (*as) = NULL;
+  free (name);
   return true;
 }
 
@@ -1527,7 +1529,7 @@ generate_finalization_wrapper (gfc_symbol *derived, gfc_namespace *ns,
   gfc_component *comp;
   gfc_namespace *sub_ns;
   gfc_code *last_code, *block;
-  char name[GFC_MAX_SYMBOL_LEN+1];
+  char *name;
   bool finalizable_comp = false;
   bool expr_null_wrapper = false;
   gfc_expr *ancestor_wrapper = NULL, *rank;
@@ -1606,7 +1608,7 @@ generate_finalization_wrapper (gfc_symbol *derived, gfc_namespace *ns,
   sub_ns->resolved = 1;
 
   /* Set up the procedure symbol.  */
-  sprintf (name, "__final_%s", tname);
+  name = xasprintf ("__final_%s", tname);
   gfc_get_symbol (name, sub_ns, &final);
   sub_ns->proc_name = final;
   final->attr.flavor = FL_PROCEDURE;
@@ -2172,6 +2174,7 @@ generate_finalization_wrapper (gfc_symbol *derived, gfc_namespace *ns,
   gfc_free_expr (rank);
   vtab_final->initializer = gfc_lval_expr_from_sym (final);
   vtab_final->ts.interface = final;
+  free (name);
 }
 
 
@@ -2239,10 +2242,11 @@ gfc_find_derived_vtab (gfc_symbol *derived)
 
   if (ns)
     {
-      char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
+      char tname[GFC_MAX_SYMBOL_LEN+1];
+      char *name;
 
       get_unique_hashed_string (tname, derived);
-      sprintf (name, "__vtab_%s", tname);
+      name = xasprintf ("__vtab_%s", tname);
 
       /* Look for the vtab symbol in various namespaces.  */
       if (gsym && gsym->ns)
@@ -2270,7 +2274,7 @@ gfc_find_derived_vtab (gfc_symbol *derived)
 	  vtab->attr.vtab = 1;
 	  vtab->attr.access = ACCESS_PUBLIC;
 	  gfc_set_sym_referenced (vtab);
-	  sprintf (name, "__vtype_%s", tname);
+	  name = xasprintf ("__vtype_%s", tname);
 
 	  gfc_find_symbol (name, ns, 0, &vtype);
 	  if (vtype == NULL)
@@ -2373,7 +2377,7 @@ gfc_find_derived_vtab (gfc_symbol *derived)
 	      else
 		{
 		  /* Construct default initialization variable.  */
-		  sprintf (name, "__def_init_%s", tname);
+		  name = xasprintf ("__def_init_%s", tname);
 		  gfc_get_symbol (name, ns, &def_init);
 		  def_init->attr.target = 1;
 		  def_init->attr.artificial = 1;
@@ -2406,7 +2410,7 @@ gfc_find_derived_vtab (gfc_symbol *derived)
 		  ns->contained = sub_ns;
 		  sub_ns->resolved = 1;
 		  /* Set up procedure symbol.  */
-		  sprintf (name, "__copy_%s", tname);
+		  name = xasprintf ("__copy_%s", tname);
 		  gfc_get_symbol (name, sub_ns, &copy);
 		  sub_ns->proc_name = copy;
 		  copy->attr.flavor = FL_PROCEDURE;
@@ -2483,7 +2487,7 @@ gfc_find_derived_vtab (gfc_symbol *derived)
 		  ns->contained = sub_ns;
 		  sub_ns->resolved = 1;
 		  /* Set up procedure symbol.  */
-		  sprintf (name, "__deallocate_%s", tname);
+		  name = xasprintf ("__deallocate_%s", tname);
 		  gfc_get_symbol (name, sub_ns, &dealloc);
 		  sub_ns->proc_name = dealloc;
 		  dealloc->attr.flavor = FL_PROCEDURE;
@@ -2532,6 +2536,7 @@ have_vtype:
 	  vtab->ts.u.derived = vtype;
 	  vtab->value = gfc_default_initializer (&vtab->ts);
 	}
+      free (name);
     }
 
   found_sym = vtab;
@@ -2623,13 +2628,14 @@ find_intrinsic_vtab (gfc_typespec *ts)
 
   if (ns)
     {
-      char name[GFC_MAX_SYMBOL_LEN+1], tname[GFC_MAX_SYMBOL_LEN+1];
-
+      char tname[GFC_MAX_SYMBOL_LEN+1];
+      char *name;
+      
       /* Encode all types as TYPENAME_KIND_ including especially character
 	 arrays, whose length is now consistently stored in the _len component
 	 of the class-variable.  */
       sprintf (tname, "%s_%d_", gfc_basic_typename (ts->type), ts->kind);
-      sprintf (name, "__vtab_%s", tname);
+      name = xasprintf ("__vtab_%s", tname);
 
       /* Look for the vtab symbol in the top-level namespace only.  */
       gfc_find_symbol (name, ns, 0, &vtab);
@@ -2646,7 +2652,7 @@ find_intrinsic_vtab (gfc_typespec *ts)
 	  vtab->attr.vtab = 1;
 	  vtab->attr.access = ACCESS_PUBLIC;
 	  gfc_set_sym_referenced (vtab);
-	  sprintf (name, "__vtype_%s", tname);
+	  name = xasprintf ("__vtype_%s", tname);
 
 	  gfc_find_symbol (name, ns, 0, &vtype);
 	  if (vtype == NULL)
@@ -2722,12 +2728,12 @@ find_intrinsic_vtab (gfc_typespec *ts)
 	      c->tb->ppc = 1;
 
 	      if (ts->type != BT_CHARACTER)
-		sprintf (name, "__copy_%s", tname);
+		name = xasprintf ("__copy_%s", tname);
 	      else
 		{
 		  /* __copy is always the same for characters.
 		     Check to see if copy function already exists.  */
-		  sprintf (name, "__copy_character_%d", ts->kind);
+		  name = xasprintf ("__copy_character_%d", ts->kind);
 		  contained = ns->contained;
 		  for (; contained; contained = contained->sibling)
 		    if (contained->proc_name
@@ -2796,6 +2802,7 @@ find_intrinsic_vtab (gfc_typespec *ts)
 	  vtab->ts.u.derived = vtype;
 	  vtab->value = gfc_default_initializer (&vtab->ts);
 	}
+      free (name);
     }
 
   found_sym = vtab;

gcc/gimple-fold.c

@@ -1340,6 +1340,19 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type,
 		 the array could have zero length.  */
 	      *minlen = ssize_int (0);
 	    }
+
+	  if (VAR_P (arg) 
+	      && TREE_CODE (TREE_TYPE (arg)) == ARRAY_TYPE)
+	    {
+	      val = TYPE_SIZE_UNIT (TREE_TYPE (arg));
+	      if (!val || TREE_CODE (val) != INTEGER_CST || integer_zerop (val))
+		return false;
+	      val = wide_int_to_tree (TREE_TYPE (val), 
+				      wi::sub(wi::to_wide (val), 1));
+	      /* Set the minimum size to zero since the string in
+		 the array could have zero length.  */
+	      *minlen = ssize_int (0);
+	    }
 	}
 
       if (!val)

gcc/testsuite/ChangeLog

+2017-12-14  Qing Zhao  <qing.zhao@oracle.com>
+
+	PR middle_end/79538
+	* gcc.dg/pr79538.c: New test.
+
 2017-12-14  David Malcolm  <dmalcolm@redhat.com>
 
 	PR tree-optimization/83312

gcc/testsuite/gcc.dg/pr79538.c

+/* PR middle-end/79538 - missing -Wformat-overflow with %s and non-member array arguments
+   { dg-do compile }
+   { dg-options "-O2 -Wformat-overflow" } */
+
+char a3[3];
+char a4[4];
+char d[3];
+
+void g (int i)
+{
+  const char *s = i < 0 ? a3 : a4;
+  __builtin_sprintf (d, "%s", s);      /* { dg-warning ".__builtin_sprintf. may write a terminating nul past the end of the destination" } */
+  return;
+}
+
+void f ()
+{
+  char des[3];
+  char src[] = "abcd";
+  __builtin_sprintf (des, "%s", src); /* { dg-warning "directive writing up to 4 bytes into a region of size 3" } */
+  return;
+}