On Wed, Aug 31, 2022 at 11:00 PM Simon Rainer <gcc....@vvalter.com> wrote: > > Hi, > > This patch fixes PR106627. I ran the i386.exp tests on my x86_64-linux-gnu > machine with a fully bootstrapped checkout. I also tested manually that no > exception handling code is generated if none of the function versions throws > an exception. > I don't have access to a machine to test the change to rs6000.cc, but the > code seems like an exact copy and I don't see a reason why it shouldn't work > there the same way. > > Regards > Simon Rainer > > From 6fcb1c742fa1d61048f7d63243225a8d1931af4a Mon Sep 17 00:00:00 2001 > From: Simon Rainer <gcc....@vvalter.com> > Date: Wed, 31 Aug 2022 20:56:04 +0200 > Subject: [PATCH] ipa: Fix throw in multi-versioned functions [PR106627] > > Any multi-versioned function was implicitly declared as noexcept, which > leads to an abort if an exception is thrown inside the function. > The reason for this is that the function declaration is replaced by a > newly created dispatcher declaration, which has TREE_NOTHROW always set > to 1. Instead we need to set TREE_NOTHROW to the value of the original > declaration.
Looks quite obvious. The middle-end to target interface is a bit iffy since we have to duplicate this everywhere. There's also other flags like pure/const and noreturn that do not impose correctness issues but may cause irritations if the IL gets a call to the dispatcher not marked noreturn but there's no code following. That said, the fix looks good to me. Thanks, Richard. > PR ipa/106627 > > gcc/ChangeLog: > > * config/i386/i386-features.cc > (ix86_get_function_versions_dispatcher): Set TREE_NOTHROW > correctly for dispatcher declaration > * config/rs6000/rs6000.cc (rs6000_get_function_versions_dispatcher): > Likewise > > gcc/testsuite/ChangeLog: > > * g++.target/i386/pr106627.C: New test. > --- > gcc/config/i386/i386-features.cc | 1 + > gcc/config/rs6000/rs6000.cc | 1 + > gcc/testsuite/g++.target/i386/pr106627.C | 30 ++++++++++++++++++++++++ > 3 files changed, 32 insertions(+) > create mode 100644 gcc/testsuite/g++.target/i386/pr106627.C > > diff --git a/gcc/config/i386/i386-features.cc > b/gcc/config/i386/i386-features.cc > index d6bb66cbe01..5b3b1aeff28 100644 > --- a/gcc/config/i386/i386-features.cc > +++ b/gcc/config/i386/i386-features.cc > @@ -3268,6 +3268,7 @@ ix86_get_function_versions_dispatcher (void *decl) > > /* Right now, the dispatching is done via ifunc. */ > dispatch_decl = make_dispatcher_decl (default_node->decl); > + TREE_NOTHROW(dispatch_decl) = TREE_NOTHROW(fn); > > dispatcher_node = cgraph_node::get_create (dispatch_decl); > gcc_assert (dispatcher_node != NULL); > diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc > index 2f3146e56f8..9280da8a5c8 100644 > --- a/gcc/config/rs6000/rs6000.cc > +++ b/gcc/config/rs6000/rs6000.cc > @@ -24861,6 +24861,7 @@ rs6000_get_function_versions_dispatcher (void *decl) > > /* Right now, the dispatching is done via ifunc. */ > dispatch_decl = make_dispatcher_decl (default_node->decl); > + TREE_NOTHROW(dispatch_decl) = TREE_NOTHROW(fn); > > dispatcher_node = cgraph_node::get_create (dispatch_decl); > gcc_assert (dispatcher_node != NULL); > diff --git a/gcc/testsuite/g++.target/i386/pr106627.C > b/gcc/testsuite/g++.target/i386/pr106627.C > new file mode 100644 > index 00000000000..a67f5ae4813 > --- /dev/null > +++ b/gcc/testsuite/g++.target/i386/pr106627.C > @@ -0,0 +1,30 @@ > +/* PR c++/103012 Exception handling with multiversioned functions */ > +/* { dg-do run } */ > +/* { dg-require-ifunc "" } */ > + > +#include <assert.h> > + > +__attribute__((target("default"))) > +void f() { > + throw 1; > +} > + > +__attribute__((target("sse4.2,bmi"))) > +void f() { > + throw 2; > +} > + > +int main() > +{ > + try { > + f(); > + } > + catch(...) > + { > + return 0; > + } > + > + assert (false); > + return 1; > +} > + > -- > 2.34.1 >