| Message ID | 20220129012123.713600-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Reject union std::initializer_list [PR102434] | expand |
On 1/28/22 20:21, Marek Polacek wrote: > Weird things are going to happen if you define your std::initializer_list > as a union. In this case, we crash in output_constructor_regular_field. > > Let's not allow such a definition in the first place. > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? OK. > PR c++/102434 > > gcc/cp/ChangeLog: > > * class.cc (finish_struct): Don't allow union initializer_list. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/initlist128.C: New test. > --- > gcc/cp/class.cc | 2 ++ > gcc/testsuite/g++.dg/cpp0x/initlist128.C | 16 ++++++++++++++++ > 2 files changed, 18 insertions(+) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist128.C > > diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc > index 5db3722ae46..696155714e8 100644 > --- a/gcc/cp/class.cc > +++ b/gcc/cp/class.cc > @@ -7766,6 +7766,8 @@ finish_struct (tree t, tree attributes) > ok = true; > } > } > + /* It also cannot be a union. */ > + ok &= NON_UNION_CLASS_TYPE_P (t); > if (!ok) > fatal_error (input_location, "definition of %qD does not match " > "%<#include <initializer_list>%>", TYPE_NAME (t)); > diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist128.C b/gcc/testsuite/g++.dg/cpp0x/initlist128.C > new file mode 100644 > index 00000000000..22246860f4e > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/initlist128.C > @@ -0,0 +1,16 @@ > +// PR c++/102434 > +// { dg-do compile { target c++11 } } > + > +using size_t = decltype(sizeof 0); > + > +namespace std { > + template<typename T> union initializer_list { // { dg-error "definition of .*std::initializer_list.* does not match" } > + const T *ptr; > + size_t n; > + }; > +} > +template<typename T> > +void Task() {} > +auto b = { &Task<int> }; > + > +// { dg-prune-output "compilation terminated" } > > base-commit: f6f2d6cfec1c2fe9570b98211be58329d8d7749b
diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc index 5db3722ae46..696155714e8 100644 --- a/gcc/cp/class.cc +++ b/gcc/cp/class.cc @@ -7766,6 +7766,8 @@ finish_struct (tree t, tree attributes) ok = true; } } + /* It also cannot be a union. */ + ok &= NON_UNION_CLASS_TYPE_P (t); if (!ok) fatal_error (input_location, "definition of %qD does not match " "%<#include <initializer_list>%>", TYPE_NAME (t)); diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist128.C b/gcc/testsuite/g++.dg/cpp0x/initlist128.C new file mode 100644 index 00000000000..22246860f4e --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/initlist128.C @@ -0,0 +1,16 @@ +// PR c++/102434 +// { dg-do compile { target c++11 } } + +using size_t = decltype(sizeof 0); + +namespace std { + template<typename T> union initializer_list { // { dg-error "definition of .*std::initializer_list.* does not match" } + const T *ptr; + size_t n; + }; +} +template<typename T> +void Task() {} +auto b = { &Task<int> }; + +// { dg-prune-output "compilation terminated" }