| Message ID | 20170327173050.GJ3172@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Mar 27, 2017 at 7:30 PM, Marek Polacek <polacek@redhat.com> wrote: > The code in fold_comparison calls save_expr on an expression and then tries to > set a location of the expression. But since save_expr calls fold, it can > produce an integer constant, so we must be more careful when setting its > location. In this case we had > > (int) a > 646 > > where 'a' is signed char so we fold it to 0. > > Bootstrapped/regtested on x86_64-linux, ok for trunk/6? > > 2017-03-27 Marek Polacek <polacek@redhat.com> > > PR sanitizer/80067 > * fold-const.c (fold_comparison): Use protected_set_expr_location > instead of SET_EXPR_LOCATION. > > * c-c++-common/ubsan/shift-10.c: New test. > > diff --git gcc/fold-const.c gcc/fold-const.c > index 1a9a264..6db16b5 100644 > --- gcc/fold-const.c > +++ gcc/fold-const.c > @@ -8704,7 +8704,7 @@ fold_comparison (location_t loc, enum tree_code code, tree type, > if (save_p) > { > tem = save_expr (build2 (code, type, cval1, cval2)); > - SET_EXPR_LOCATION (tem, loc); > + protected_set_expr_location (tem, loc); I believe using tem = save_expr (build2_loc (loc, code, type, cval1, cval2)); would have worked just fine. save_expr uses the exprs location (if available). But the patch is ok as well. Richard. > return tem; > } > return fold_build2_loc (loc, code, type, cval1, cval2); > diff --git gcc/testsuite/c-c++-common/ubsan/shift-10.c gcc/testsuite/c-c++-common/ubsan/shift-10.c > index e69de29..9202fcc 100644 > --- gcc/testsuite/c-c++-common/ubsan/shift-10.c > +++ gcc/testsuite/c-c++-common/ubsan/shift-10.c > @@ -0,0 +1,10 @@ > +/* PR sanitizer/80067 */ > +/* { dg-do compile } */ > +/* { dg-options "-fsanitize=shift" } */ > + > +extern signed char a; > +void > +foo () > +{ > + 0 << ((647 > a) - 1); > +} > > Marek
diff --git gcc/fold-const.c gcc/fold-const.c index 1a9a264..6db16b5 100644 --- gcc/fold-const.c +++ gcc/fold-const.c @@ -8704,7 +8704,7 @@ fold_comparison (location_t loc, enum tree_code code, tree type, if (save_p) { tem = save_expr (build2 (code, type, cval1, cval2)); - SET_EXPR_LOCATION (tem, loc); + protected_set_expr_location (tem, loc); return tem; } return fold_build2_loc (loc, code, type, cval1, cval2); diff --git gcc/testsuite/c-c++-common/ubsan/shift-10.c gcc/testsuite/c-c++-common/ubsan/shift-10.c index e69de29..9202fcc 100644 --- gcc/testsuite/c-c++-common/ubsan/shift-10.c +++ gcc/testsuite/c-c++-common/ubsan/shift-10.c @@ -0,0 +1,10 @@ +/* PR sanitizer/80067 */ +/* { dg-do compile } */ +/* { dg-options "-fsanitize=shift" } */ + +extern signed char a; +void +foo () +{ + 0 << ((647 > a) - 1); +}