teak-llvm/clang/test/CodeGenCXX/ctor-dtor-alias.cpp
Chandler Carruth 1f82d9ba6e Revert r337456: [CodeGen] Disable aggressive structor optimizations at -O0, take 3
This commit increases the number of sections and overall output size of
.o files by 10% and sometimes a bit more. This alone is challenging for
some users, but it also appears to trigger an as-yet unexplained
behavior in the Gold linker where the memory usage increases
considerably more than 10% (we think).

The increase is also frustrating because in many (if not all) cases we
end up with almost all of the growth coming from the ELF overhead of
-ffunction-sections and such, not from actual extra code being emitted.

Richard Smith and Eric Christopher are both going to investigate this
and try to get to the bottom of what is triggering this and whether the
kinds of increases here are sustainable or what options we might have to
minimize the impact they have. However, this is currently breaking
a pretty large number of our users' builds so reverting it while we sort
out how to make progress here. I've seen a longer and more detailed
update to the commit thread.

llvm-svn: 338209
2018-07-29 03:05:07 +00:00

249 lines
6.8 KiB
C++

// RUN: %clang_cc1 %s -triple i686-linux -emit-llvm -o - -mconstructor-aliases | FileCheck --check-prefix=NOOPT %s
// RUN: %clang_cc1 %s -triple i686-linux -emit-llvm -o - -mconstructor-aliases -O1 -disable-llvm-passes > %t
// RUN: FileCheck --check-prefix=CHECK1 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK2 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK3 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK4 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK5 --input-file=%t %s
// RUN: FileCheck --check-prefix=CHECK6 --input-file=%t %s
// RUN: %clang_cc1 %s -triple i686-pc-windows-gnu -emit-llvm -o - -mconstructor-aliases -O1 -disable-llvm-passes | FileCheck --check-prefix=COFF %s
namespace test1 {
// Test that we produce the appropriate comdats when creating aliases to
// weak_odr constructors and destructors.
// CHECK1: @_ZN5test16foobarIvEC1Ev = weak_odr unnamed_addr alias void {{.*}} @_ZN5test16foobarIvEC2Ev
// CHECK1: @_ZN5test16foobarIvED1Ev = weak_odr unnamed_addr alias void (%"struct.test1::foobar"*), void (%"struct.test1::foobar"*)* @_ZN5test16foobarIvED2Ev
// CHECK1: define weak_odr void @_ZN5test16foobarIvEC2Ev({{.*}} comdat($_ZN5test16foobarIvEC5Ev)
// CHECK1: define weak_odr void @_ZN5test16foobarIvED2Ev({{.*}} comdat($_ZN5test16foobarIvED5Ev)
// CHECK1: define weak_odr void @_ZN5test16foobarIvED0Ev({{.*}} comdat($_ZN5test16foobarIvED5Ev)
// CHECK1-NOT: comdat
// COFF doesn't support comdats with arbitrary names (C5/D5).
// COFF: define weak_odr {{.*}} void @_ZN5test16foobarIvEC2Ev({{.*}} comdat align
// COFF: define weak_odr {{.*}} void @_ZN5test16foobarIvEC1Ev({{.*}} comdat align
// COFF: define weak_odr {{.*}} void @_ZN5test16foobarIvED2Ev({{.*}} comdat align
// COFF: define weak_odr {{.*}} void @_ZN5test16foobarIvED0Ev({{.*}} comdat align
template <typename T>
struct foobar {
foobar() {}
virtual ~foobar() {}
};
template struct foobar<void>;
}
namespace test2 {
// test that when the destrucor is linkonce_odr we just replace every use of
// C1 with C2.
// CHECK1: define internal void @__cxx_global_var_init()
// CHECK1: call void @_ZN5test26foobarIvEC2Ev
// CHECK1: define linkonce_odr void @_ZN5test26foobarIvEC2Ev({{.*}} comdat align
void g();
template <typename T> struct foobar {
foobar() { g(); }
};
foobar<void> x;
}
namespace test3 {
// test that instead of an internal alias we just use the other destructor
// directly.
// CHECK1: define internal void @__cxx_global_var_init.1()
// CHECK1: call i32 @__cxa_atexit{{.*}}_ZN5test312_GLOBAL__N_11AD2Ev
// CHECK1: define internal void @_ZN5test312_GLOBAL__N_11AD2Ev(
namespace {
struct A {
~A() {}
};
struct B : public A {};
}
B x;
}
namespace test4 {
// Test that we don't produce aliases from B to A. We cannot because we cannot
// guarantee that they will be present in every TU. Instead, we just call
// A's destructor directly.
// CHECK1: define internal void @__cxx_global_var_init.2()
// CHECK1: call i32 @__cxa_atexit{{.*}}_ZN5test41AD2Ev
// CHECK1: define linkonce_odr void @_ZN5test41AD2Ev({{.*}} comdat align
// test that we don't do this optimization at -O0 so that the debugger can
// see both destructors.
// NOOPT: define internal void @__cxx_global_var_init.2()
// NOOPT: call i32 @__cxa_atexit{{.*}}@_ZN5test41BD2Ev
// NOOPT: define linkonce_odr void @_ZN5test41BD2Ev({{.*}} comdat align
struct A {
virtual ~A() {}
};
struct B : public A{
~B() {}
};
B X;
}
namespace test5 {
// similar to test4, but with an internal B.
// CHECK2: define internal void @__cxx_global_var_init.3()
// CHECK2: call i32 @__cxa_atexit{{.*}}_ZN5test51AD2Ev
// CHECK2: define linkonce_odr void @_ZN5test51AD2Ev({{.*}} comdat align
struct A {
virtual ~A() {}
};
namespace {
struct B : public A{
~B() {}
};
}
B X;
}
namespace test6 {
// Test that we use ~A directly, even when ~A is not defined. The symbol for
// ~B would have been internal and still contain a reference to ~A.
struct A {
virtual ~A();
};
namespace {
struct B : public A {
~B() {}
};
}
B X;
// CHECK3: define internal void @__cxx_global_var_init.4()
// CHECK3: call i32 @__cxa_atexit({{.*}}@_ZN5test61AD2Ev
}
namespace test7 {
// Test that we don't produce an alias from ~B to ~A<int> (or crash figuring
// out if we should).
// pr17875.
// CHECK3: define void @_ZN5test71BD2Ev
template <typename> struct A {
~A() {}
};
class B : A<int> {
~B();
};
template class A<int>;
B::~B() {}
}
namespace test8 {
// Test that we replace ~zed with ~bar which is an alias to ~foo.
// CHECK4: @_ZN5test83barD2Ev = unnamed_addr alias {{.*}} @_ZN5test83fooD2Ev
// CHECK4: define internal void @__cxx_global_var_init.5()
// CHECK4: call i32 @__cxa_atexit({{.*}}@_ZN5test83barD2Ev
struct foo {
~foo();
};
foo::~foo() {}
struct bar : public foo {
~bar();
};
bar::~bar() {}
struct zed : public bar {};
zed foo;
}
namespace test9 {
struct foo {
__attribute__((stdcall)) ~foo() {
}
};
struct bar : public foo {};
void zed() {
// Test that we produce a call to bar's destructor. We used to call foo's, but
// it has a different calling conversion.
// CHECK4: call void @_ZN5test93barD2Ev
bar ptr;
}
}
// CHECK5: @_ZTV1C = linkonce_odr unnamed_addr constant { [4 x i8*] } {{[^@]*}}@_ZTI1C {{[^@]*}}@_ZN1CD2Ev {{[^@]*}}@_ZN1CD0Ev {{[^@]*}}]
// r194296 replaced C::~C with B::~B without emitting the later.
class A {
public:
A(int);
virtual ~A();
};
template <class>
class B : A {
public:
B()
: A(0) {
}
__attribute__((always_inline)) ~B() {
}
};
extern template class B<char>;
class C : B<char> {
};
void
fn1() {
new C;
}
namespace test10 {
// Test that if a destructor is in a comdat, we don't try to emit is as an
// alias to a base class destructor.
struct bar {
~bar();
};
bar::~bar() {
}
} // closing the namespace causes ~bar to be sent to CodeGen
namespace test10 {
template <typename T>
struct foo : public bar {
~foo();
};
template <typename T>
foo<T>::~foo() {}
template class foo<int>;
// CHECK5: define weak_odr void @_ZN6test103fooIiED2Ev({{.*}} comdat($_ZN6test103fooIiED5Ev)
}
namespace test11 {
// Test that when we don't have to worry about COMDATs we produce an alias
// from complate to base and from base to base class base.
struct bar {
~bar();
};
bar::~bar() {}
struct foo : public bar {
~foo();
};
foo::~foo() {}
// CHECK6: @_ZN6test113fooD2Ev = unnamed_addr alias {{.*}} @_ZN6test113barD2Ev
// CHECK6: @_ZN6test113fooD1Ev = unnamed_addr alias {{.*}} @_ZN6test113fooD2Ev
}
namespace test12 {
template <int>
struct foo {
~foo() { delete this; }
};
template class foo<1>;
// CHECK6: @_ZN6test123fooILi1EED1Ev = weak_odr unnamed_addr alias {{.*}} @_ZN6test123fooILi1EED2Ev
// CHECK6: define weak_odr void @_ZN6test123fooILi1EED2Ev({{.*}}) {{.*}} comdat($_ZN6test123fooILi1EED5Ev)
}