| Message ID | 20161130190242.GB3541@tucnak.redhat.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Nov 30, 2016 at 8:02 PM, Jakub Jelinek <jakub@redhat.com> wrote: > Hi! > > This patch fixes 3 spots with UB in dwarf2out.c, furthermore the first spot > results in smaller/better debug info. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? Ok. Thanks, Richard. > 2016-11-30 Jakub Jelinek <jakub@redhat.com> > > PR debug/78587 > * dwarf2out.c (loc_descr_plus_const): For negative offset use > uint_loc_descriptor instead of int_loc_descriptor and perform negation > in unsigned HOST_WIDE_INT type. > (scompare_loc_descriptor): Shift UINTVAL left instead of INTVAL. > > * gcc.dg/debug/pr78587.c: New test. > > --- gcc/dwarf2out.c.jj 2016-11-18 22:55:19.000000000 +0100 > +++ gcc/dwarf2out.c 2016-11-30 15:16:39.402673343 +0100 > @@ -1514,7 +1514,8 @@ loc_descr_plus_const (dw_loc_descr_ref * > > else > { > - loc->dw_loc_next = int_loc_descriptor (-offset); > + loc->dw_loc_next > + = uint_loc_descriptor (-(unsigned HOST_WIDE_INT) offset); > add_loc_descr (&loc->dw_loc_next, new_loc_descr (DW_OP_minus, 0, 0)); > } > } > @@ -13837,7 +13838,7 @@ scompare_loc_descriptor (enum dwarf_loca > if (CONST_INT_P (XEXP (rtl, 1)) > && GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT > && (size_of_int_loc_descriptor (shift) + 1 > - + size_of_int_loc_descriptor (INTVAL (XEXP (rtl, 1)) << shift) > + + size_of_int_loc_descriptor (UINTVAL (XEXP (rtl, 1)) << shift) > >= size_of_int_loc_descriptor (GET_MODE_MASK (op_mode)) + 1 > + size_of_int_loc_descriptor (INTVAL (XEXP (rtl, 1)) > & GET_MODE_MASK (op_mode)))) > @@ -13852,7 +13853,7 @@ scompare_loc_descriptor (enum dwarf_loca > add_loc_descr (&op0, int_loc_descriptor (shift)); > add_loc_descr (&op0, new_loc_descr (DW_OP_shl, 0, 0)); > if (CONST_INT_P (XEXP (rtl, 1))) > - op1 = int_loc_descriptor (INTVAL (XEXP (rtl, 1)) << shift); > + op1 = int_loc_descriptor (UINTVAL (XEXP (rtl, 1)) << shift); > else > { > add_loc_descr (&op1, int_loc_descriptor (shift)); > --- gcc/testsuite/gcc.dg/debug/pr78587.c.jj 2016-11-30 15:01:08.855153232 +0100 > +++ gcc/testsuite/gcc.dg/debug/pr78587.c 2016-11-30 15:20:22.000000000 +0100 > @@ -0,0 +1,23 @@ > +/* PR debug/78587 */ > +/* { dg-do compile } */ > +/* { dg-additional-options "-w" } */ > + > +extern void bar (void); > + > +void > +foo (long long x) > +{ > + x ^= 9223372036854775808ULL; > + bar (); > +} > + > +struct S { int w[4]; } a[1], b; > + > +void > +baz () > +{ > + int e = (int) baz; > + if (e <= -80) > + e = 0; > + b = a[e]; > +} > > Jakub
--- gcc/dwarf2out.c.jj 2016-11-18 22:55:19.000000000 +0100 +++ gcc/dwarf2out.c 2016-11-30 15:16:39.402673343 +0100 @@ -1514,7 +1514,8 @@ loc_descr_plus_const (dw_loc_descr_ref * else { - loc->dw_loc_next = int_loc_descriptor (-offset); + loc->dw_loc_next + = uint_loc_descriptor (-(unsigned HOST_WIDE_INT) offset); add_loc_descr (&loc->dw_loc_next, new_loc_descr (DW_OP_minus, 0, 0)); } } @@ -13837,7 +13838,7 @@ scompare_loc_descriptor (enum dwarf_loca if (CONST_INT_P (XEXP (rtl, 1)) && GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT && (size_of_int_loc_descriptor (shift) + 1 - + size_of_int_loc_descriptor (INTVAL (XEXP (rtl, 1)) << shift) + + size_of_int_loc_descriptor (UINTVAL (XEXP (rtl, 1)) << shift) >= size_of_int_loc_descriptor (GET_MODE_MASK (op_mode)) + 1 + size_of_int_loc_descriptor (INTVAL (XEXP (rtl, 1)) & GET_MODE_MASK (op_mode)))) @@ -13852,7 +13853,7 @@ scompare_loc_descriptor (enum dwarf_loca add_loc_descr (&op0, int_loc_descriptor (shift)); add_loc_descr (&op0, new_loc_descr (DW_OP_shl, 0, 0)); if (CONST_INT_P (XEXP (rtl, 1))) - op1 = int_loc_descriptor (INTVAL (XEXP (rtl, 1)) << shift); + op1 = int_loc_descriptor (UINTVAL (XEXP (rtl, 1)) << shift); else { add_loc_descr (&op1, int_loc_descriptor (shift)); --- gcc/testsuite/gcc.dg/debug/pr78587.c.jj 2016-11-30 15:01:08.855153232 +0100 +++ gcc/testsuite/gcc.dg/debug/pr78587.c 2016-11-30 15:20:22.000000000 +0100 @@ -0,0 +1,23 @@ +/* PR debug/78587 */ +/* { dg-do compile } */ +/* { dg-additional-options "-w" } */ + +extern void bar (void); + +void +foo (long long x) +{ + x ^= 9223372036854775808ULL; + bar (); +} + +struct S { int w[4]; } a[1], b; + +void +baz () +{ + int e = (int) baz; + if (e <= -80) + e = 0; + b = a[e]; +}