From 025d57f037ad13eb479818b677ef4be4d97b639c Mon Sep 17 00:00:00 2001
From: Martin Sebor <msebor@redhat.com>
Date: Fri, 10 Nov 2017 16:35:26 +0000
Subject: PR c/81117 - Improve buffer overflow checking in strncpy

gcc/ChangeLog:

	PR c/81117
	* builtins.c (compute_objsize): Handle arrays that
	compute_builtin_object_size likes to fail for.  Make extern.
	* builtins.h (compute_objsize): Declare.
	(check_strncpy_sizes): New function.
	(expand_builtin_strncpy): Call check_strncpy_sizes.
	* gimple-fold.c (gimple_fold_builtin_strncpy): Implement
	-Wstringop-truncation.
	(gimple_fold_builtin_strncat): Same.
	* gimple.c (gimple_build_call_from_tree): Set call location.
	* tree-ssa-strlen.c (strlen_to_stridx): New global variable.
	(maybe_diag_bound_equal_length, is_strlen_related_p): New functions.
	(handle_builtin_stxncpy, handle_builtin_strncat): Same.
	(handle_builtin_strlen): Use strlen_to_stridx.
	(strlen_optimize_stmt): Handle flavors of strncat, strncpy, and
	stpncpy.
	Use strlen_to_stridx.
	(pass_strlen::execute): Release strlen_to_stridx.
	* doc/invoke.texi (-Wsizeof-pointer-memaccess): Document enhancement.
	(-Wstringop-truncation): Document new option.

gcc/ada/ChangeLog:

	PR c/81117
	* ada/adadecode.c (__gnat_decode): Use memcpy instead of strncpy.
	* ada/argv.c (__gnat_fill_arg, __gnat_fill_env): Same.

gcc/c-family/ChangeLog:

	PR c/81117
	* c-common.c (catenate_strings): Use memcpy instead of strncpy.
	* c-warn.c (sizeof_pointer_memaccess_warning): Handle arrays.
	* c.opt (-Wstringop-truncation): New option.

gcc/fortran/ChangeLog:

	PR c/81117
	* gcc/fortran/decl.c (build_sym): Use strcpy instead of strncpy.

gcc/objc/ChangeLog:

	PR c/81117
	* objc-encoding.c (encode_type): Use memcpy instead of strncpy.

gcc/testsuite/ChangeLog:

	PR c/81117
	* c-c++-common/Wsizeof-pointer-memaccess3.c: New test.
	* c-c++-common/Wstringop-overflow.c: Same.
	* c-c++-common/Wstringop-truncation.c: Same.
	* c-c++-common/Wsizeof-pointer-memaccess2.c: Adjust.
	* c-c++-common/attr-nonstring-2.c: New test.
	* g++.dg/torture/Wsizeof-pointer-memaccess1.C: Adjust.
	* g++.dg/torture/Wsizeof-pointer-memaccess2.C: Same.
	* gcc.dg/torture/pr63554.c: Same.
	* gcc.dg/Walloca-1.c: Disable macro tracking.

From-SVN: r254630
---
 gcc/testsuite/gcc.dg/builtin-stpncpy.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

(limited to 'gcc/testsuite/gcc.dg/builtin-stpncpy.c')

diff --git a/gcc/testsuite/gcc.dg/builtin-stpncpy.c b/gcc/testsuite/gcc.dg/builtin-stpncpy.c
index e4290d5..9200798 100644
--- a/gcc/testsuite/gcc.dg/builtin-stpncpy.c
+++ b/gcc/testsuite/gcc.dg/builtin-stpncpy.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/80669 - Bad -Wstringop-overflow warnings for stpncpy
    { dg-do compile }
-   { dg-options "-O2 -Wall" } */
+   { dg-options "-O2 -Wall -Wno-stringop-truncation" } */
 
 #define SIZE_MAX __SIZE_MAX__
 
@@ -18,7 +18,9 @@ size_t range (size_t min, size_t max)
   return val < min || max < val ? min : val;
 }
 
-/* Verify that no warning is issued for stpncpy with constant size.  */
+/* Verify that no -Wstringop-overflow warning is issued for stpncpy
+   with constant size.  (Some tests cause -Wstringop-truncation and
+   that's expected).  */
 void test_cst (char *d)
 {
   __builtin_stpncpy (d, "123", 0);
@@ -37,7 +39,8 @@ void test_cst (char *d)
 }
 
 
-/* Verify that no warning is issued for stpncpy with size in some range.  */
+/* Verify that no -Wstringop-overflow warning is issued for stpncpy
+   with size in some range.  */
 void test_rng (char *d)
 {
 #define R(min, max) range (min, max)
-- 
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