llvm-project/clang/test/CodeGenCXX/mangle-variadic-templates.cpp
Sirraide 12f78e740c
[Clang] [NFC] Fix unintended -Wreturn-type warnings everywhere in the test suite (#123464)
In preparation of making `-Wreturn-type` default to an error (as there
is virtually no situation where you’d *want* to fall off the end of a
function that is supposed to return a value), this patch fixes tests
that have relied on this being only a warning, of which there seem 
to be 3 kinds:

1. Tests which for no apparent reason have a function that triggers the
warning.

I suspect that a lot of these were on accident (or from before the
warning was introduced), since a lot of people will open issues w/ their
problematic code in the `main` function (which is the one case where you
don’t need to return from a non-void function, after all...), which
someone will then copy, possibly into a namespace, possibly renaming it,
the end result of that being that you end up w/ something that
definitely is not `main` anymore, but which still is declared as
returning `int`, and which still has no return statement (another reason
why I think this might apply to a lot of these is because usually the
actual return type of such problematic functions is quite literally
`int`).
  
A lot of these are really old tests that don’t use `-verify`, which is
why no-one noticed or had to care about the extra warning that was
already being emitted by them until now.

2. Tests which test either `-Wreturn-type`, `[[noreturn]]`, or what
codegen and sanitisers do whenever you do fall off the end of a
function.

3. Tests where I struggle to figure out what is even being tested
(usually because they’re Objective-C tests, and I don’t know
Objective-C), whether falling off the end of a function matters in the
first place, and tests where actually spelling out an expression to
return would be rather cumbersome (e.g. matrix types currently don’t
support list initialisation, so I can’t write e.g. `return {}`).

For tests that fall into categories 2 and 3, I just added
`-Wno-error=return-type` to the `RUN` lines and called it a day. This
was especially necessary for the former since `-Wreturn-type` is an
analysis-based warning, meaning that it is currently impossible to test
for more than one occurrence of it in the same compilation if it
defaults to an error since the analysis pass is skipped for subsequent
functions as soon as an error is emitted.

I’ve also added `-Werror=return-type` to a few tests that I had already
updated as this patch was previously already making the warning an error
by default, but we’ve decided to split that into two patches instead.
2025-01-18 19:16:33 +01:00

78 lines
3.2 KiB
C++

// RUN: %clang_cc1 -Wno-error=return-type -std=c++11 -emit-llvm -triple=x86_64-apple-darwin9 -o - %s | FileCheck %s
template<unsigned I, typename ...Types>
struct X { };
template<typename T> struct identity { using type = T; };
template<typename T> struct add_reference;
template<typename ...Types> struct tuple { };
template<int ...Values> struct int_tuple { };
template<template<typename> class ...Templates> struct template_tuple { };
template<typename ...T> using ArrayOfN = int[sizeof...(T)];
// CHECK-LABEL: define weak_odr void @_Z2f0IJEEv1XIXsZT_EJDpRT_EE
template<typename ...Types>
void f0(X<sizeof...(Types), Types&...>) { }
template void f0(X<0>);
// CHECK-LABEL: define weak_odr void @_Z2f0IJifdEEv1XIXsZT_EJDpRT_EE
template void f0<int, float, double>(X<3, int&, float&, double&>);
// Mangling for template argument packs
template<typename ...Types> void f1() {}
// CHECK-LABEL: define weak_odr void @_Z2f1IJEEvv
template void f1<>();
// CHECK-LABEL: define weak_odr void @_Z2f1IJiEEvv
template void f1<int>();
// CHECK-LABEL: define weak_odr void @_Z2f1IJifEEvv
template void f1<int, float>();
// Mangling function parameter packs
template<typename ...Types> void f2(Types...) {}
// CHECK-LABEL: define weak_odr void @_Z2f2IJEEvDpT_
template void f2<>();
// CHECK-LABEL: define weak_odr void @_Z2f2IJiEEvDpT_
template void f2<int>(int);
// CHECK-LABEL: define weak_odr void @_Z2f2IJifEEvDpT_
template void f2<int, float>(int, float);
// Mangling non-trivial function parameter packs
template<typename ...Types> void f3(const Types *...) {}
// CHECK-LABEL: define weak_odr void @_Z2f3IJEEvDpPKT_
template void f3<>();
// CHECK-LABEL: define weak_odr void @_Z2f3IJiEEvDpPKT_
template void f3<int>(const int*);
// CHECK-LABEL: define weak_odr void @_Z2f3IJifEEvDpPKT_
template void f3<int, float>(const int*, const float*);
// Mangling of type pack expansions in a template argument
template<typename ...Types> tuple<Types...> f4() { return {}; }
// CHECK-LABEL: define weak_odr void @_Z2f4IJifdEE5tupleIJDpT_EEv
template tuple<int, float, double> f4();
// Mangling of type pack expansions in a function type
template<typename R, typename ...ArgTypes> identity<R(ArgTypes...)> f5() {}
// CHECK-LABEL: define weak_odr void @_Z2f5IiJifdEE8identityIFT_DpT0_EEv
template identity<int(int, float, double)> f5();
// Mangling of non-type template argument expansions
template<int ...Values> int_tuple<Values...> f6() {}
// CHECK-LABEL: define weak_odr void @_Z2f6IJLi1ELi2ELi3EEE9int_tupleIJXspT_EEEv
template int_tuple<1, 2, 3> f6();
// Mangling of template template argument expansions
template<template<typename> class ...Templates>
template_tuple<Templates...> f7() {}
// CHECK-LABEL: define weak_odr void @_Z2f7IJ8identity13add_referenceEE14template_tupleIJDpT_EEv
template template_tuple<identity, add_reference> f7();
template<typename T, typename ...U> void f8(ArrayOfN<int, U..., T, typename U::type...>&) {}
// CHECK-LABEL: define weak_odr void @_Z2f8IiJ8identityIiES0_IfEEEvRAsPiDpT0_T_DpNS3_4typeEE_i
template void f8<int, identity<int>, identity<float>>(int (&)[6]);
template<typename ...T> void f10(ArrayOfN<T...> &) {}
// FIXME: This is wrong; should be @_Z3f10IJifEEvRAsZT__i
// CHECK-LABEL: define weak_odr void @_Z3f10IJifEEvRAsPDpT_E_i
template void f10<int, float>(int (&)[2]);