// RUN: %clang_cc1 -verify -fsyntax-only -fms-extensions -fcxx-exceptions -fopenmp -triple x86_64-linux %s
int ReturnsInt1();
int Func1() {
[[clang::musttail]] ReturnsInt1(); // expected-error {{'musttail' attribute only applies to return statements}}
[[clang::musttail(1, 2)]] return ReturnsInt1(); // expected-error {{'musttail' attribute takes no arguments}}
[[clang::musttail]] return 5; // expected-error {{'musttail' attribute requires that the return value is the result of a function call}}
[[clang::musttail]] return ReturnsInt1();
}
void NoFunctionCall() {
[[clang::musttail]] return; // expected-error {{'musttail' attribute requires that the return value is the result of a function call}}
}
[[clang::musttail]] static int int_val = ReturnsInt1(); // expected-error {{'musttail' attribute cannot be applied to a declaration}}
void NoParams(); // expected-note {{target function has different number of parameters (expected 1 but has 0)}}
void TestParamArityMismatch(int x) {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return NoParams(); // expected-error {{cannot perform a tail call to function 'NoParams' because its signature is incompatible with the calling function}}
}
void LongParam(long x); // expected-note {{target function has type mismatch at 1st parameter (expected 'long' but has 'int')}}
void TestParamTypeMismatch(int x) {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return LongParam(x); // expected-error {{cannot perform a tail call to function 'LongParam' because its signature is incompatible with the calling function}}
}
long ReturnsLong(); // expected-note {{target function has different return type ('int' expected but has 'long')}}
int TestReturnTypeMismatch() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return ReturnsLong(); // expected-error {{cannot perform a tail call to function 'ReturnsLong' because its signature is incompatible with the calling function}}
}
struct Struct1 {
void MemberFunction(); // expected-note {{'MemberFunction' declared here}}
};
void TestNonMemberToMember() {
Struct1 st;
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return st.MemberFunction(); // expected-error {{non-member function cannot perform a tail call to non-static member function 'MemberFunction'}}
}
void ReturnsVoid(); // expected-note {{'ReturnsVoid' declared here}}
struct Struct2 {
void TestMemberToNonMember() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return ReturnsVoid(); // expected-error{{non-static member function cannot perform a tail call to non-member function 'ReturnsVoid'}}
}
};
class HasNonTrivialDestructor {
public:
~HasNonTrivialDestructor() {}
int ReturnsInt();
};
void ReturnsVoid2();
void TestNonTrivialDestructorInScope() {
HasNonTrivialDestructor foo; // expected-note {{jump exits scope of variable with non-trivial destructor}}
[[clang::musttail]] return ReturnsVoid(); // expected-error {{cannot perform a tail call from this return statement}}
}
int NonTrivialParam(HasNonTrivialDestructor x);
int TestNonTrivialParam(HasNonTrivialDestructor x) {
[[clang::musttail]] return NonTrivialParam(x); // expected-error {{tail call requires that the return value, all parameters, and any temporaries created by the expression are trivially destructible}}
}
HasNonTrivialDestructor ReturnsNonTrivialValue();
HasNonTrivialDestructor TestReturnsNonTrivialValue() {
// FIXME: the diagnostic cannot currently distinguish between needing to run a
// destructor for the return value and needing to run a destructor for some
// other temporary created in the return statement.
[[clang::musttail]] return (ReturnsNonTrivialValue()); // expected-error {{tail call requires that the return value, all parameters, and any temporaries created by the expression are trivially destructible}}
}
HasNonTrivialDestructor TestReturnsNonTrivialNonFunctionCall() {
[[clang::musttail]] return HasNonTrivialDestructor(); // expected-error {{'musttail' attribute requires that the return value is the result of a function call}}
}
struct UsesPointerToMember {
void (UsesPointerToMember::*p_mem)(); // expected-note {{'p_mem' declared here}}
};
void TestUsesPointerToMember(UsesPointerToMember *foo) {
// "this" pointer cannot double as first parameter.
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return (foo->*(foo->p_mem))(); // expected-error {{non-member function cannot perform a tail call to pointer-to-member function 'p_mem'}}
}
void ReturnsVoid2();
void TestNestedClass() {
HasNonTrivialDestructor foo;
class Nested {
__attribute__((noinline)) static void NestedMethod() {
// Outer non-trivial destructor does not affect nested class.
[[clang::musttail]] return ReturnsVoid2();
}
};
}
template <class T>
T TemplateFunc(T x) { // expected-note{{target function has different return type ('long' expected but has 'int')}}
return x ? 5 : 10;
}
int OkTemplateFunc(int x) {
[[clang::musttail]] return TemplateFunc<int>(x);
}
template <class T>
T BadTemplateFunc(T x) {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return TemplateFunc<int>(x); // expected-error {{cannot perform a tail call to function 'TemplateFunc' because its signature is incompatible with the calling function}}
}
long TestBadTemplateFunc(long x) {
return BadTemplateFunc<long>(x); // expected-note {{in instantiation of}}
}
void IntParam(int x);
void TestVLA(int x) {
HasNonTrivialDestructor vla[x]; // expected-note {{jump exits scope of variable with non-trivial destructor}}
[[clang::musttail]] return IntParam(x); // expected-error {{cannot perform a tail call from this return statement}}
}
void TestNonTrivialDestructorSubArg(int x) {
[[clang::musttail]] return IntParam(NonTrivialParam(HasNonTrivialDestructor())); // expected-error {{tail call requires that the return value, all parameters, and any temporaries created by the expression are trivially destructible}}
}
void VariadicFunction(int x, ...);
void TestVariadicFunction(int x, ...) {
[[clang::musttail]] return VariadicFunction(x); // expected-error {{'musttail' attribute may not be used with variadic functions}}
}
int TakesIntParam(int x); // expected-note {{target function has type mismatch at 1st parameter (expected 'int' but has 'short')}}
int TakesShortParam(short x); // expected-note {{target function has type mismatch at 1st parameter (expected 'short' but has 'int')}}
int TestIntParamMismatch(int x) {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return TakesShortParam(x); // expected-error {{cannot perform a tail call to function 'TakesShortParam' because its signature is incompatible with the calling function}}
}
int TestIntParamMismatch2(short x) {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return TakesIntParam(x); // expected-error {{cannot perform a tail call to function 'TakesIntParam' because its signature is incompatible with the calling function}}
}
struct TestClassMismatch1 {
void ToFunction(); // expected-note{{target function is a member of different class (expected 'TestClassMismatch2' but has 'TestClassMismatch1')}}
};
TestClassMismatch1 *tcm1;
struct TestClassMismatch2 {
void FromFunction() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return tcm1->ToFunction(); // expected-error {{cannot perform a tail call to function 'ToFunction' because its signature is incompatible with the calling function}}
}
};
__regcall int RegCallReturnsInt(); // expected-note {{target function has calling convention regcall (expected cdecl)}}
int TestMismatchCallingConvention() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return RegCallReturnsInt(); // expected-error {{cannot perform a tail call to function 'RegCallReturnsInt' because it uses an incompatible calling convention}}
}
int TestNonCapturingLambda() {
auto lambda = []() { return 12; }; // expected-note {{'operator()' declared here}}
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return lambda(); // expected-error {{non-member function cannot perform a tail call to non-static member function 'operator()'}}
// This works.
auto lambda_fptr = static_cast<int (*)()>(lambda);
[[clang::musttail]] return lambda_fptr();
[[clang::musttail]] return (+lambda)();
}
int TestCapturingLambda() {
int x;
auto lambda = [x]() { return 12; }; // expected-note {{'operator()' declared here}}
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return lambda(); // expected-error {{non-member function cannot perform a tail call to non-static member function 'operator()'}}
}
int TestNonTrivialTemporary(int) {
[[clang::musttail]] return TakesIntParam(HasNonTrivialDestructor().ReturnsInt()); // expected-error {{tail call requires that the return value, all parameters, and any temporaries created by the expression are trivially destructible}}
}
void ReturnsVoid();
struct TestDestructor {
~TestDestructor() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return ReturnsVoid(); // expected-error {{destructor '~TestDestructor' must not return void expression}} // expected-error {{cannot perform a tail call from a destructor}}
}
};
struct ClassWithDestructor { // expected-note {{target destructor is declared here}}
void TestExplicitDestructorCall() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return this->~ClassWithDestructor(); // expected-error {{cannot perform a tail call to a destructor}}
}
};
struct HasNonTrivialCopyConstructor {
HasNonTrivialCopyConstructor(const HasNonTrivialCopyConstructor &);
};
HasNonTrivialCopyConstructor ReturnsClassByValue();
HasNonTrivialCopyConstructor TestNonElidableCopyConstructor() {
// This is an elidable constructor, but when it is written explicitly
// we decline to elide it.
[[clang::musttail]] return HasNonTrivialCopyConstructor(ReturnsClassByValue()); // expected-error{{'musttail' attribute requires that the return value is the result of a function call}}
}
struct ClassWithConstructor {
ClassWithConstructor() = default; // expected-note {{target constructor is declared here}}
};
void TestExplicitConstructorCall(ClassWithConstructor a) {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return a.ClassWithConstructor::ClassWithConstructor(); // expected-error{{cannot perform a tail call to a constructor}} expected-warning{{explicit constructor calls are a Microsoft extension}}
}
void TestStatementExpression() {
({
HasNonTrivialDestructor foo; // expected-note {{jump exits scope of variable with non-trivial destructor}}
[[clang::musttail]] return ReturnsVoid2(); // expected-error {{cannot perform a tail call from this return statement}}
});
}
struct MyException {};
void TestTryBlock() {
try { // expected-note {{jump exits try block}}
[[clang::musttail]] return ReturnsVoid2(); // expected-error {{cannot perform a tail call from this return statement}}
} catch (MyException &e) {
}
}
using IntFunctionType = int();
IntFunctionType *ReturnsIntFunction();
long TestRValueFunctionPointer() {
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return ReturnsIntFunction()(); // expected-error{{cannot perform a tail call to function because its signature is incompatible with the calling function}} // expected-note{{target function has different return type ('long' expected but has 'int')}}
}
void TestPseudoDestructor() {
int n;
using T = int;
[[clang::musttail]] // expected-note {{tail call required by 'musttail' attribute here}}
return n.~T(); // expected-error{{cannot perform a tail call to a destructor}}
}
struct StructPMF {
typedef void (StructPMF::*PMF)();
static void TestReturnsPMF();
};
StructPMF *St;
StructPMF::PMF ReturnsPMF();
void StructPMF::TestReturnsPMF() {
[[clang::musttail]] // expected-note{{tail call required by 'musttail' attribute here}}
return (St->*ReturnsPMF())(); // expected-error{{static member function cannot perform a tail call to pointer-to-member function}}
}
// These tests are merely verifying that we don't crash with incomplete or
// erroneous ASTs. These cases crashed the compiler in early iterations.
struct TestBadPMF {
int (TestBadPMF::*pmf)();
void BadPMF() {
[[clang::musttail]] return ((*this)->*pmf)(); // expected-error {{left hand operand to ->* must be a pointer to class compatible with the right hand operand, but is 'TestBadPMF'}}
}
};
namespace ns {}
void TestCallNonValue() {
[[clang::musttail]] return ns; // expected-error {{unexpected namespace name 'ns': expected expression}}
}
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