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re PR sanitizer/89869 (-fsanitize=undefined miscompilation) 

PR sanitizer/89869
	* typeck.c: Include gimplify.h.
	(cp_build_modify_expr) <case COND_EXPR>: Unshare rhs before using it
	for second time.  Formatting fixes.

	* g++.dg/ubsan/vptr-14.C: New test.

From-SVN: r270024
This commit is contained in:
Jakub Jelinek 2019-03-29 21:10:19 +01:00 committed by Jakub Jelinek
parent 77527d8ac4
commit 2b53407efb
4 changed files with 44 additions and 9 deletions
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7
gcc/cp/ChangeLog
View File

@ -1,3 +1,10 @@
2019-03-29 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/89869
* typeck.c: Include gimplify.h.
(cp_build_modify_expr) <case COND_EXPR>: Unshare rhs before using it
for second time. Formatting fixes.
2019-03-29 Marek Polacek <polacek@redhat.com>
PR c++/89876 - ICE with deprecated conversion.

25
gcc/cp/typeck.c
View File

@ -40,6 +40,7 @@ along with GCC; see the file COPYING3. If not see
#include "stringpool.h"
#include "attribs.h"
#include "asan.h"
#include "gimplify.h"
static tree cp_build_addr_expr_strict (tree, tsubst_flags_t);
static tree cp_build_function_call (tree, tree, tsubst_flags_t);
@ -8129,8 +8130,6 @@ cp_build_modify_expr (location_t loc, tree lhs, enum tree_code modifycode,
/* Produce (a ? (b = rhs) : (c = rhs))
except that the RHS goes through a save-expr
so the code to compute it is only emitted once. */
tree cond;
if (VOID_TYPE_P (TREE_TYPE (rhs)))
{
if (complain & tf_error)
@ -8145,13 +8144,21 @@ cp_build_modify_expr (location_t loc, tree lhs, enum tree_code modifycode,
if (!lvalue_or_else (lhs, lv_assign, complain))
return error_mark_node;
cond = build_conditional_expr
(input_location, TREE_OPERAND (lhs, 0),
cp_build_modify_expr (loc, TREE_OPERAND (lhs, 1),
modifycode, rhs, complain),
cp_build_modify_expr (loc, TREE_OPERAND (lhs, 2),
modifycode, rhs, complain),
complain);
tree op1 = cp_build_modify_expr (loc, TREE_OPERAND (lhs, 1),
modifycode, rhs, complain);
/* When sanitizing undefined behavior, even when rhs doesn't need
stabilization at this point, the sanitization might add extra
SAVE_EXPRs in there and so make sure there is no tree sharing
in the rhs, otherwise those SAVE_EXPRs will have initialization
only in one of the two branches. */
if (sanitize_flags_p (SANITIZE_UNDEFINED
| SANITIZE_UNDEFINED_NONDEFAULT))
rhs = unshare_expr (rhs);
tree op2 = cp_build_modify_expr (loc, TREE_OPERAND (lhs, 2),
modifycode, rhs, complain);
tree cond = build_conditional_expr (input_location,
TREE_OPERAND (lhs, 0), op1, op2,
complain);
if (cond == error_mark_node)
return cond;

3
gcc/testsuite/ChangeLog
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@ -1,5 +1,8 @@
2019-03-29 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/89869
* g++.dg/ubsan/vptr-14.C: New test.
PR c/89872
* gcc.dg/tree-ssa/pr89872.c: New test.

18
gcc/testsuite/g++.dg/ubsan/vptr-14.C Normal file
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@ -0,0 +1,18 @@
// PR sanitizer/89869
// { dg-do run }
// { dg-options "-fsanitize=vptr -fno-sanitize-recover=vptr" }
struct S { S *s = 0; virtual ~S () {} };
void
foo (S *x, S *y)
{
(x->s ? y : x) = x->s;
}
int
main ()
{
S a;
foo (&a, 0);
}