| Message ID | 20160404155052.GA19779@kam.mff.cuni.cz |
|---|---|
| State | New |
| Headers | show |
On Mon, Apr 04, 2016 at 05:50:53PM +0200, Jan Hubicka wrote: > Hi, > as requested by Jakub, this patch makes devirtualization code to turn off > transformations based on assumption that cxa_pure_virtual will never be called > by a virtual call when -fsanitize=undefined is used. > > Bootstrapped/regtested x86_64-linux, will commit it shortly. > > PR ipa/66223 > * ipa-devirt.c (maybe_record_node): Do not optimize cxa_pure_virtual > calls when sanitizing. > (possible_polymorphic_call_target_p)" FIx formating. > > * g++.dg/ipa/devirt-51.C: New testcase. > Index: ipa-devirt.c > =================================================================== > --- ipa-devirt.c (revision 234715) > +++ ipa-devirt.c (working copy) > @@ -2438,10 +2438,14 @@ maybe_record_node (vec <cgraph_node *> & > { > gcc_assert (!target_node->global.inlined_to); > gcc_assert (target_node->real_symbol_p ()); > + /* When sanitizing, do not asume that cxa_pure_virutal is not called s/asume/assume/ s/cxa/__cxa/ s/virutal/virtual/ > + by valid program. */ > + if (flag_sanitize & SANITIZE_UNDEFINED) > + ; I'd use SANITIZE_UNREACHABLE instead, that is the sanitizer for __builtin_unreachable (). Unless we want to split that into -fsanitize=unreachable -fsanitize=pure-virtual Jakub
> On Mon, Apr 04, 2016 at 05:50:53PM +0200, Jan Hubicka wrote: > > Hi, > > as requested by Jakub, this patch makes devirtualization code to turn off > > transformations based on assumption that cxa_pure_virtual will never be called > > by a virtual call when -fsanitize=undefined is used. > > > > Bootstrapped/regtested x86_64-linux, will commit it shortly. > > > > PR ipa/66223 > > * ipa-devirt.c (maybe_record_node): Do not optimize cxa_pure_virtual > > calls when sanitizing. > > (possible_polymorphic_call_target_p)" FIx formating. > > > > * g++.dg/ipa/devirt-51.C: New testcase. > > Index: ipa-devirt.c > > =================================================================== > > --- ipa-devirt.c (revision 234715) > > +++ ipa-devirt.c (working copy) > > @@ -2438,10 +2438,14 @@ maybe_record_node (vec <cgraph_node *> & > > { > > gcc_assert (!target_node->global.inlined_to); > > gcc_assert (target_node->real_symbol_p ()); > > + /* When sanitizing, do not asume that cxa_pure_virutal is not called > > s/asume/assume/ > s/cxa/__cxa/ > s/virutal/virtual/ > > > + by valid program. */ > > + if (flag_sanitize & SANITIZE_UNDEFINED) > > + ; > > I'd use SANITIZE_UNREACHABLE instead, that is the sanitizer for > __builtin_unreachable (). Unless we want to split that into > -fsanitize=unreachable > -fsanitize=pure-virtual Thanks. This is about case where we optimize undefined call (which would otherwise land in cxa_pure_virtual) into some other virtual method (that is the only resonable choice). I suppose UNREACHABLE makes sense here. I think I already commited the patch but I will update this. Honza > > Jakub
Index: ipa-devirt.c =================================================================== --- ipa-devirt.c (revision 234715) +++ ipa-devirt.c (working copy) @@ -2438,10 +2438,14 @@ maybe_record_node (vec <cgraph_node *> & { gcc_assert (!target_node->global.inlined_to); gcc_assert (target_node->real_symbol_p ()); + /* When sanitizing, do not asume that cxa_pure_virutal is not called + by valid program. */ + if (flag_sanitize & SANITIZE_UNDEFINED) + ; /* Only add pure virtual if it is the only possible target. This way we will preserve the diagnostics about pure virtual called in many cases without disabling optimization in other. */ - if (pure_virtual) + else if (pure_virtual) { if (nodes.length ()) return; @@ -3374,8 +3378,7 @@ possible_polymorphic_call_target_p (tree bool final; if (TREE_CODE (TREE_TYPE (n->decl)) == FUNCTION_TYPE - && ((fcode = DECL_FUNCTION_CODE (n->decl)) - == BUILT_IN_UNREACHABLE + && ((fcode = DECL_FUNCTION_CODE (n->decl)) == BUILT_IN_UNREACHABLE || fcode == BUILT_IN_TRAP)) return true; Index: testsuite/g++.dg/ipa/devirt-51.C =================================================================== --- testsuite/g++.dg/ipa/devirt-51.C (revision 0) +++ testsuite/g++.dg/ipa/devirt-51.C (working copy) @@ -0,0 +1,29 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fsanitize=undefined -fdump-tree-optimized" } */ +namespace { + struct B { + B* self; + B() : self( this ) { self->f(); } + void E(void); + virtual void f() = 0; + }; + + struct D : B + { + void f() {} + }; +} + +struct D e; + +__attribute__ ((used)) +void B::E(void) + { + this->f(); +} + + int main() + { + D d; + } +/* { dg-final { scan-tree-dump "cxa_pure_virtual" "optimized" } } */