builtins.c (unterminated_array): Handle ARRAY_REF.

	* builtins.c (unterminated_array): Handle ARRAY_REF.
	(expand_builtin_stpcpy_1): Detect unterminated char arrays.
	* builtins.h (unterminated_array): Declare extern.
	* gimple-fold.c (gimple_fold_builtin_stpcpy): Detect unterminated
	  arrays.
	(gimple_fold_builtin_sprintf): Propagate NO_WARNING to transformed
	calls.

	* gcc.dg/warn-stpcpy-no-nul.c: New test.

From-SVN: r264328

gcc/ChangeLog

 2018-09-14  Martin Sebor  <msebor@redhat.com>
+
+	* builtins.c (unterminated_array): Handle ARRAY_REF.
+	(expand_builtin_stpcpy_1): Detect unterminated char arrays.
+	* builtins.h (unterminated_array): Declare extern.
+	* gimple-fold.c (gimple_fold_builtin_stpcpy): Detect unterminated
+	arrays.
+	(gimple_fold_builtin_sprintf): Propagate NO_WARNING to transformed
+	calls.
+
+2018-09-14  Martin Sebor  <msebor@redhat.com>
 	    Jeff Law  <law@redhat.com>
 
 	* builtins.c (unterminated_array): New.

gcc/builtins.c

@@ -567,7 +567,7 @@ warn_string_no_nul (location_t loc, const char *fn, tree arg, tree decl)
    the declaration of the object of which the array is a member or
    element.  Otherwise return null.  */
 
-static tree
+tree
 unterminated_array (tree exp)
 {
   if (TREE_CODE (exp) == SSA_NAME)
@@ -578,7 +578,10 @@ unterminated_array (tree exp)
 
       tree rhs1 = gimple_assign_rhs1 (stmt);
       tree_code code = gimple_assign_rhs_code (stmt);
-      if (code != POINTER_PLUS_EXPR)
+      if (code == ADDR_EXPR
+	  && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF)
+	rhs1 = rhs1;
+      else if (code != POINTER_PLUS_EXPR)
 	return NULL_TREE;
 
       exp = rhs1;
@@ -3981,9 +3984,14 @@ expand_builtin_stpcpy_1 (tree exp, rtx target, machine_mode mode)
 	 compile-time, not an expression containing a string.  This is
 	 because the latter will potentially produce pessimized code
 	 when used to produce the return value.  */
-      if (! c_getstr (src) || ! (len = c_strlen (src, 0)))
+      tree nonstr = NULL_TREE;
+      if (!c_getstr (src, NULL)
+	  || !(len = c_strlen (src, 0, &nonstr, 1)))
 	return expand_movstr (dst, src, target, /*endp=*/2);
 
+      if (nonstr && !TREE_NO_WARNING (exp))
+	warn_string_no_nul (EXPR_LOCATION (exp), "stpcpy", src, nonstr);
+
       lenp1 = size_binop_loc (loc, PLUS_EXPR, len, ssize_int (1));
       ret = expand_builtin_mempcpy_args (dst, src, lenp1,
 					 target, exp, /*endp=*/2);

gcc/builtins.h

@@ -104,6 +104,7 @@ extern internal_fn associated_internal_fn (tree);
 extern internal_fn replacement_internal_fn (gcall *);
 
 extern void warn_string_no_nul (location_t, const char *, tree, tree);
+extern tree unterminated_array (tree);
 extern tree max_object_size ();
 
 #endif /* GCC_BUILTINS_H */

gcc/gimple-fold.c

@@ -2798,7 +2798,7 @@ gimple_fold_builtin_stpcpy (gimple_stmt_iterator *gsi)
   location_t loc = gimple_location (stmt);
   tree dest = gimple_call_arg (stmt, 0);
   tree src = gimple_call_arg (stmt, 1);
-  tree fn, len, lenp1;
+  tree fn, lenp1;
 
   /* If the result is unused, replace stpcpy with strcpy.  */
   if (gimple_call_lhs (stmt) == NULL_TREE)
@@ -2811,10 +2811,25 @@ gimple_fold_builtin_stpcpy (gimple_stmt_iterator *gsi)
       return true;
     }
 
-  len = c_strlen (src, 1);
+  /* Set to non-null if ARG refers to an unterminated array.  */
+  tree nonstr = NULL;
+  tree len = c_strlen (src, 1, &nonstr, 1);
   if (!len
       || TREE_CODE (len) != INTEGER_CST)
-    return false;
+    {
+      nonstr = unterminated_array (src);
+      if (!nonstr)
+	return false;
+    }
+
+  if (nonstr)
+    {
+      /* Avoid folding calls with unterminated arrays.  */
+      if (!gimple_no_warning_p (stmt))
+	warn_string_no_nul (loc, "stpcpy", src, nonstr);
+      gimple_set_no_warning (stmt, true);
+      return false;
+    }
 
   if (optimize_function_for_size_p (cfun)
       /* If length is zero it's small enough.  */
@@ -3077,6 +3092,12 @@ gimple_fold_builtin_sprintf (gimple_stmt_iterator *gsi)
 	 'format' is known to contain no % formats.  */
       gimple_seq stmts = NULL;
       gimple *repl = gimple_build_call (fn, 2, dest, fmt);
+
+      /* Propagate the NO_WARNING bit to avoid issuing the same
+	 warning more than once.  */
+      if (gimple_no_warning_p (stmt))
+	gimple_set_no_warning (repl, true);
+
       gimple_seq_add_stmt_without_update (&stmts, repl);
       if (gimple_call_lhs (stmt))
 	{
@@ -3125,6 +3146,12 @@ gimple_fold_builtin_sprintf (gimple_stmt_iterator *gsi)
       /* Convert sprintf (str1, "%s", str2) into strcpy (str1, str2).  */
       gimple_seq stmts = NULL;
       gimple *repl = gimple_build_call (fn, 2, dest, orig);
+
+      /* Propagate the NO_WARNING bit to avoid issuing the same
+	 warning more than once.  */
+      if (gimple_no_warning_p (stmt))
+	gimple_set_no_warning (repl, true);
+
       gimple_seq_add_stmt_without_update (&stmts, repl);
       if (gimple_call_lhs (stmt))
 	{

gcc/testsuite/ChangeLog

 2018-09-14  Martin Sebor  <msebor@redhat.com>
+
+	* gcc.dg/warn-stpcpy-no-nul.c: New test.
+
+2018-09-14  Martin Sebor  <msebor@redhat.com>
 	    Jeff Law  <law@redhat.com>
 
 	* gcc.dg/warn-strcpy-no-nul.c: New test.