Erik Pilkington 5a559e64a9 Add a new flag and attributes to control static destructor registration
This commit adds the flag -fno-c++-static-destructors and the attributes
[[clang::no_destroy]] and [[clang::always_destroy]]. no_destroy specifies that a
specific static or thread duration variable shouldn't have it's destructor
registered, and is the default in -fno-c++-static-destructors mode.
always_destroy is the opposite, and is the default in -fc++-static-destructors
mode.

A variable whose destructor is disabled (either because of
-fno-c++-static-destructors or [[clang::no_destroy]]) doesn't count as a use of
the destructor, so we don't do any access checking or mark it referenced. We
also don't emit -Wexit-time-destructors for these variables.

rdar://21734598

Differential revision: https://reviews.llvm.org/D50994

llvm-svn: 340306
2018-08-21 17:24:06 +00:00

32 lines
880 B
C++

// RUN: %clang_cc1 %s -emit-llvm -triple x86_64-apple-macosx10.13.0 -o - | FileCheck %s
struct NonTrivial {
~NonTrivial();
};
// CHECK-NOT: __cxa_atexit{{.*}}_ZN10NonTrivialD1Ev
[[clang::no_destroy]] NonTrivial nt1;
// CHECK-NOT: _tlv_atexit{{.*}}_ZN10NonTrivialD1Ev
[[clang::no_destroy]] thread_local NonTrivial nt2;
struct NonTrivial2 {
~NonTrivial2();
};
// CHECK: __cxa_atexit{{.*}}_ZN11NonTrivial2D1Ev
NonTrivial2 nt21;
// CHECK: _tlv_atexit{{.*}}_ZN11NonTrivial2D1Ev
thread_local NonTrivial2 nt22;
void f() {
// CHECK: __cxa_atexit{{.*}}_ZN11NonTrivial2D1Ev
static NonTrivial2 nt21;
// CHECK: _tlv_atexit{{.*}}_ZN11NonTrivial2D1Ev
thread_local NonTrivial2 nt22;
}
// CHECK: __cxa_atexit{{.*}}_ZN10NonTrivialD1Ev
[[clang::always_destroy]] NonTrivial nt3;
// CHECK: _tlv_atexit{{.*}}_ZN10NonTrivialD1Ev
[[clang::always_destroy]] thread_local NonTrivial nt4;