llvm-project/clang/test/CodeGenCXX/cxx1y-sized-deallocation.cpp

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C++14: Disable sized deallocation by default due to ABI breakage There are no widely deployed standard libraries providing sized deallocation functions, so we have to punt and ask the user if they want us to use sized deallocation. In the future, when such libraries are deployed, we can teach the driver to detect them and enable this feature. N3536 claimed that a weak thunk from sized to unsized deallocation could be emitted to avoid breaking backwards compatibility with standard libraries not providing sized deallocation. However, this approach and other variations don't work in practice. With the weak function approach, the thunk has to have default visibility in order to ensure that it is overridden by other DSOs providing sized deallocation. Weak, default visibility symbols are particularly expensive on MachO, so John McCall was considering disabling this feature by default on Darwin. It also changes behavior ELF linking behavior, causing certain otherwise unreferenced object files from an archive to be pulled into the link. Our second approach was to use an extern_weak function declaration and do an inline conditional branch at the deletion call site. This doesn't work because extern_weak only works on MachO if you have some archive providing the default value of the extern_weak symbol. Arranging to provide such an archive has the same challenges as providing the symbol in the standard library. Not to mention that extern_weak doesn't really work on COFF. Reviewers: rsmith, rjmccall Differential Revision: http://reviews.llvm.org/D8467 llvm-svn: 232788
2015-03-20 08:31:07 +08:00
// Check that delete exprs call the sized deallocation function if
// -fsized-deallocation is passed in both C++11 and C++14.
// RUN: %clang_cc1 -std=c++11 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
// RUN: %clang_cc1 -std=c++14 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
// Check that we don't used sized deallocation without -fsized-deallocation and
// C++14.
// RUN: %clang_cc1 -std=c++11 %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
C++14: Disable sized deallocation by default due to ABI breakage There are no widely deployed standard libraries providing sized deallocation functions, so we have to punt and ask the user if they want us to use sized deallocation. In the future, when such libraries are deployed, we can teach the driver to detect them and enable this feature. N3536 claimed that a weak thunk from sized to unsized deallocation could be emitted to avoid breaking backwards compatibility with standard libraries not providing sized deallocation. However, this approach and other variations don't work in practice. With the weak function approach, the thunk has to have default visibility in order to ensure that it is overridden by other DSOs providing sized deallocation. Weak, default visibility symbols are particularly expensive on MachO, so John McCall was considering disabling this feature by default on Darwin. It also changes behavior ELF linking behavior, causing certain otherwise unreferenced object files from an archive to be pulled into the link. Our second approach was to use an extern_weak function declaration and do an inline conditional branch at the deletion call site. This doesn't work because extern_weak only works on MachO if you have some archive providing the default value of the extern_weak symbol. Arranging to provide such an archive has the same challenges as providing the symbol in the standard library. Not to mention that extern_weak doesn't really work on COFF. Reviewers: rsmith, rjmccall Differential Revision: http://reviews.llvm.org/D8467 llvm-svn: 232788
2015-03-20 08:31:07 +08:00
// RUN: %clang_cc1 -std=c++14 %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
// CHECK-UNSIZED-NOT: _ZdlPvm
// CHECK-UNSIZED-NOT: _ZdaPvm
typedef decltype(sizeof(0)) size_t;
typedef int A;
struct B { int n; };
struct C { ~C() {} };
struct D { D(); virtual ~D() {} };
struct E {
void *operator new(size_t);
void *operator new[](size_t);
void operator delete(void *) noexcept;
void operator delete[](void *) noexcept;
};
struct F {
void *operator new(size_t);
void *operator new[](size_t);
void operator delete(void *, size_t) noexcept;
void operator delete[](void *, size_t) noexcept;
};
template<typename T> T get();
template<typename T>
void del() {
::delete get<T*>();
::delete[] get<T*>();
delete get<T*>();
delete[] get<T*>();
}
template void del<A>();
template void del<B>();
template void del<C>();
template void del<D>();
template void del<E>();
template void del<F>();
D::D() {}
// CHECK-LABEL: define weak_odr void @_Z3delIiEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
//
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
C++14: Disable sized deallocation by default due to ABI breakage There are no widely deployed standard libraries providing sized deallocation functions, so we have to punt and ask the user if they want us to use sized deallocation. In the future, when such libraries are deployed, we can teach the driver to detect them and enable this feature. N3536 claimed that a weak thunk from sized to unsized deallocation could be emitted to avoid breaking backwards compatibility with standard libraries not providing sized deallocation. However, this approach and other variations don't work in practice. With the weak function approach, the thunk has to have default visibility in order to ensure that it is overridden by other DSOs providing sized deallocation. Weak, default visibility symbols are particularly expensive on MachO, so John McCall was considering disabling this feature by default on Darwin. It also changes behavior ELF linking behavior, causing certain otherwise unreferenced object files from an archive to be pulled into the link. Our second approach was to use an extern_weak function declaration and do an inline conditional branch at the deletion call site. This doesn't work because extern_weak only works on MachO if you have some archive providing the default value of the extern_weak symbol. Arranging to provide such an archive has the same challenges as providing the symbol in the standard library. Not to mention that extern_weak doesn't really work on COFF. Reviewers: rsmith, rjmccall Differential Revision: http://reviews.llvm.org/D8467 llvm-svn: 232788
2015-03-20 08:31:07 +08:00
// CHECK-LABEL: declare void @_ZdlPvm(i8*
// CHECK-LABEL: define weak_odr void @_Z3delI1BEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
//
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
// CHECK-LABEL: define weak_odr void @_Z3delI1CEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 1)
// CHECK: mul i64 1, %{{[^ ]*}}
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
//
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 1)
// CHECK: mul i64 1, %{{[^ ]*}}
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
C++14: Disable sized deallocation by default due to ABI breakage There are no widely deployed standard libraries providing sized deallocation functions, so we have to punt and ask the user if they want us to use sized deallocation. In the future, when such libraries are deployed, we can teach the driver to detect them and enable this feature. N3536 claimed that a weak thunk from sized to unsized deallocation could be emitted to avoid breaking backwards compatibility with standard libraries not providing sized deallocation. However, this approach and other variations don't work in practice. With the weak function approach, the thunk has to have default visibility in order to ensure that it is overridden by other DSOs providing sized deallocation. Weak, default visibility symbols are particularly expensive on MachO, so John McCall was considering disabling this feature by default on Darwin. It also changes behavior ELF linking behavior, causing certain otherwise unreferenced object files from an archive to be pulled into the link. Our second approach was to use an extern_weak function declaration and do an inline conditional branch at the deletion call site. This doesn't work because extern_weak only works on MachO if you have some archive providing the default value of the extern_weak symbol. Arranging to provide such an archive has the same challenges as providing the symbol in the standard library. Not to mention that extern_weak doesn't really work on COFF. Reviewers: rsmith, rjmccall Differential Revision: http://reviews.llvm.org/D8467 llvm-svn: 232788
2015-03-20 08:31:07 +08:00
// CHECK-LABEL: declare void @_ZdaPvm(i8*
// CHECK-LABEL: define weak_odr void @_Z3delI1DEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 8)
// CHECK: mul i64 8, %{{[^ ]*}}
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
//
// CHECK-NOT: Zdl
// CHECK: call void %{{.*}}
// CHECK-NOT: Zdl
// CHECK: mul i64 8, %{{[^ ]*}}
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
// CHECK-LABEL: define weak_odr void @_Z3delI1EEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 1)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
//
// CHECK: call void @_ZN1EdlEPv(i8* %{{[^ ]*}})
// CHECK: call void @_ZN1EdaEPv(i8* %{{[^ ]*}})
// CHECK-LABEL: define weak_odr void @_Z3delI1FEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 1)
// CHECK: mul i64 1, %{{[^ ]*}}
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
//
// CHECK: call void @_ZN1FdlEPvm(i8* %{{[^ ]*}}, i64 1)
// CHECK: mul i64 1, %{{[^ ]*}}
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZN1FdaEPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
// CHECK-LABEL: define linkonce_odr void @_ZN1DD0Ev(%{{[^ ]*}}* {{[^,]*}} %this)
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 8)