72315d02c4
This is extended to all `std::` functions that take a reference to a value and return a reference (or pointer) to that same value: `move`, `forward`, `move_if_noexcept`, `as_const`, `addressof`, and the libstdc++-specific function `__addressof`. We still require these functions to be declared before they can be used, but don't instantiate their definitions unless their addresses are taken. Instead, code generation, constant evaluation, and static analysis are given direct knowledge of their effect. This change aims to reduce various costs associated with these functions -- per-instantiation memory costs, compile time and memory costs due to creating out-of-line copies and inlining them, code size at -O0, and so on -- so that they are not substantially more expensive than a cast. Most of these improvements are very small, but I measured a 3% decrease in -O0 object file size for a simple C++ source file using the standard library after this change. We now automatically infer the `const` and `nothrow` attributes on these now-builtin functions, in particular meaning that we get a warning for an unused call to one of these functions. In C++20 onwards, we disallow taking the addresses of these functions, per the C++20 "addressable function" rule. In earlier language modes, a compatibility warning is produced but the address can still be taken. The same infrastructure is extended to the existing MSVC builtin `__GetExceptionInfo`, which is now only recognized in namespace `std` like it always should have been. This is a re-commit offc30901096,a571f82a50,64c045e25b, andde6ddaeef3, and revertsaa643f455a. This change also includes a workaround for users using libc++ 3.1 and earlier (!!), as apparently happens on AIX, where std::move sometimes returns by value. Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D123345 Revert "Fixup D123950 to address revert of D123345" This reverts commitaa643f455a.
162 lines
9.2 KiB
C++
162 lines
9.2 KiB
C++
// RUN: %clang_cc1 -no-opaque-pointers -emit-llvm -o - -triple=i386-pc-win32 -std=c++11 %s -fcxx-exceptions -fms-extensions | FileCheck %s
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// CHECK-DAG: @"??_R0?AUY@@@8" = linkonce_odr global %rtti.TypeDescriptor7 { i8** @"??_7type_info@@6B@", i8* null, [8 x i8] c".?AUY@@\00" }, comdat
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// CHECK-DAG: @"_CT??_R0?AUY@@@8??0Y@@QAE@ABU0@@Z8" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 4, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUY@@@8" to i8*), i32 0, i32 -1, i32 0, i32 8, i8* bitcast (%struct.Y* (%struct.Y*, %struct.Y*, i32)* @"??0Y@@QAE@ABU0@@Z" to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @"??_R0?AUZ@@@8" = linkonce_odr global %rtti.TypeDescriptor7 { i8** @"??_7type_info@@6B@", i8* null, [8 x i8] c".?AUZ@@\00" }, comdat
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// CHECK-DAG: @"_CT??_R0?AUZ@@@81" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUZ@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* null }, section ".xdata", comdat
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// CHECK-DAG: @"??_R0?AUW@@@8" = linkonce_odr global %rtti.TypeDescriptor7 { i8** @"??_7type_info@@6B@", i8* null, [8 x i8] c".?AUW@@\00" }, comdat
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// CHECK-DAG: @"_CT??_R0?AUW@@@8??0W@@QAE@ABU0@@Z44" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 4, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUW@@@8" to i8*), i32 4, i32 -1, i32 0, i32 4, i8* bitcast (%struct.W* (%struct.W*, %struct.W*, i32)* @"??0W@@QAE@ABU0@@Z" to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @"??_R0?AUM@@@8" = linkonce_odr global %rtti.TypeDescriptor7 { i8** @"??_7type_info@@6B@", i8* null, [8 x i8] c".?AUM@@\00" }, comdat
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// CHECK-DAG: @"_CT??_R0?AUM@@@818" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUM@@@8" to i8*), i32 8, i32 -1, i32 0, i32 1, i8* null }, section ".xdata", comdat
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// CHECK-DAG: @"??_R0?AUV@@@8" = linkonce_odr global %rtti.TypeDescriptor7 { i8** @"??_7type_info@@6B@", i8* null, [8 x i8] c".?AUV@@\00" }, comdat
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// CHECK-DAG: @"_CT??_R0?AUV@@@81044" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUV@@@8" to i8*), i32 0, i32 4, i32 4, i32 1, i8* null }, section ".xdata", comdat
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// CHECK-DAG: @"_CTA5?AUY@@" = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.5 { i32 5, [5 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0?AUY@@@8??0Y@@QAE@ABU0@@Z8", %eh.CatchableType* @"_CT??_R0?AUZ@@@81", %eh.CatchableType* @"_CT??_R0?AUW@@@8??0W@@QAE@ABU0@@Z44", %eh.CatchableType* @"_CT??_R0?AUM@@@818", %eh.CatchableType* @"_CT??_R0?AUV@@@81044"] }, section ".xdata", comdat
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// CHECK-DAG: @"_TI5?AUY@@" = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i8* bitcast (void (%struct.Y*)* @"??_DY@@QAEXXZ" to i8*), i8* null, i8* bitcast (%eh.CatchableTypeArray.5* @"_CTA5?AUY@@" to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @"_CT??_R0?AUDefault@@@8??_ODefault@@QAEXAAU0@@Z1" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor13* @"??_R0?AUDefault@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* bitcast (void (%struct.Default*, %struct.Default*)* @"??_ODefault@@QAEXAAU0@@Z" to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @"_CT??_R0?AUDeletedCopy@@@81" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor17* @"??_R0?AUDeletedCopy@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* null }, section ".xdata", comdat
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// CHECk-DAG: @"_CT??_R0?AUMoveOnly@@@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor14* @"??_R0?AUMoveOnly@@@8" to i8*), i32 0, i321-1, i32 0, i32 4, i8* null }, section ".xdata", comda
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// CHECK-DAG: @"_CT??_R0?AUVariadic@@@8??_OVariadic@@QAEXAAU0@@Z1" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor14* @"??_R0?AUVariadic@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* bitcast (void (%struct.Variadic*, %struct.Variadic*)* @"??_OVariadic@@QAEXAAU0@@Z" to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @"_CT??_R0?AUTemplateWithDefault@@@8??$?_OH@TemplateWithDefault@@QAEXAAU0@@Z1" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor25* @"??_R0?AUTemplateWithDefault@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* bitcast (void (%struct.TemplateWithDefault*, %struct.TemplateWithDefault*)* @"??$?_OH@TemplateWithDefault@@QAEXAAU0@@Z" to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @"_CTA2$$T" = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.2 { i32 2, [2 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0$$T@84", %eh.CatchableType* @"_CT??_R0PAX@84"] }, section ".xdata", comdat
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// CHECK-DAG: @"_CT??_R0P6AXXZ@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0P6AXXZ@8" to i8*), i32 0, i32 -1, i32 0, i32 4, i8* null }, section ".xdata", comdat
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// CHECK-DAG: @_CTA1P6AXXZ = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0P6AXXZ@84"] }, section ".xdata", comdat
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// CHECK-DAG: @_TI1P6AXXZ = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @_CTA1P6AXXZ to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @_TIU2PAPFAH = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 4, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.2* @_CTA2PAPFAH to i8*) }, section ".xdata", comdat
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// CHECK-DAG: @_CTA2PAPFAH = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.2 { i32 2, [2 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0PAPFAH@84", %eh.CatchableType* @"_CT??_R0PAX@84"] }, section ".xdata", comdat
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// CHECK-DAG: @"_TI1?AUFoo@?A0x{{[^@]*}}@@" = internal unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @"_CTA1?AUFoo@?A0x{{[^@]*}}@@" to i8*) }, section ".xdata"
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struct N { ~N(); };
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struct M : private N {};
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struct X {};
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struct Z {};
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struct V : private X {};
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struct W : M, virtual V {};
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struct Y : Z, W, virtual V {};
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void f(const Y &y) {
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// CHECK-LABEL: @"?f@@YAXABUY@@@Z"
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// CHECK: call x86_thiscallcc noundef %struct.Y* @"??0Y@@QAE@ABU0@@Z"(%struct.Y* {{[^,]*}} %[[mem:.*]], %struct.Y*
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// CHECK: %[[cast:.*]] = bitcast %struct.Y* %[[mem]] to i8*
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// CHECK: call void @_CxxThrowException(i8* %[[cast]], %eh.ThrowInfo* @"_TI5?AUY@@")
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throw y;
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}
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void g(const int *const *y) {
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// CHECK-LABEL: @"?g@@YAXPBQBH@Z"
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// CHECK: call void @_CxxThrowException(i8* %{{.*}}, %eh.ThrowInfo* @_TIC2PAPBH)
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throw y;
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}
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void h(__unaligned int * __unaligned *y) {
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// CHECK-LABEL: @"?h@@YAXPFAPFAH@Z"
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// CHECK: call void @_CxxThrowException(i8* %{{.*}}, %eh.ThrowInfo* @_TIU2PAPFAH)
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throw y;
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}
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struct Default {
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Default(Default &, int = 42);
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};
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// CHECK-LABEL: @"??_ODefault@@QAEXAAU0@@Z"
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// CHECK: %[[src_addr:.*]] = alloca
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// CHECK: %[[this_addr:.*]] = alloca
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// CHECK: store {{.*}} %src, {{.*}} %[[src_addr]], align 4
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// CHECK: store {{.*}} %this, {{.*}} %[[this_addr]], align 4
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// CHECK: %[[this:.*]] = load {{.*}} %[[this_addr]]
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// CHECK: %[[src:.*]] = load {{.*}} %[[src_addr]]
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// CHECK: call x86_thiscallcc {{.*}} @"??0Default@@QAE@AAU0@H@Z"({{.*}} %[[this]], {{.*}} %[[src]], i32 noundef 42)
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// CHECK: ret void
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void h(Default &d) {
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throw d;
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}
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struct DeletedCopy {
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DeletedCopy();
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DeletedCopy(DeletedCopy &&);
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DeletedCopy(const DeletedCopy &) = delete;
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};
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void throwDeletedCopy() { throw DeletedCopy(); }
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struct MoveOnly {
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MoveOnly();
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MoveOnly(MoveOnly &&);
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~MoveOnly();
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MoveOnly(const MoveOnly &) = delete;
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// For some reason this subobject was important for reproducing PR43680
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struct HasCopy {
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HasCopy();
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HasCopy(const HasCopy &o);
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~HasCopy();
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int x;
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} sub;
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};
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void throwMoveOnly() { throw MoveOnly(); }
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struct Variadic {
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Variadic(Variadic &, ...);
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};
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void i(Variadic &v) {
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throw v;
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}
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// CHECK-LABEL: @"??_OVariadic@@QAEXAAU0@@Z"
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// CHECK: %[[src_addr:.*]] = alloca
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// CHECK: %[[this_addr:.*]] = alloca
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// CHECK: store {{.*}} %src, {{.*}} %[[src_addr:.*]], align
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// CHECK: store {{.*}} %this, {{.*}} %[[this_addr:.*]], align
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// CHECK: %[[this:.*]] = load {{.*}} %[[this_addr]]
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// CHECK: %[[src:.*]] = load {{.*}} %[[src_addr]]
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// CHECK: call {{.*}} @"??0Variadic@@QAA@AAU0@ZZ"({{.*}} %[[this]], {{.*}} %[[src]])
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// CHECK: ret void
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struct TemplateWithDefault {
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template <typename T>
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static int f() {
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return 0;
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}
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template <typename T = int>
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TemplateWithDefault(TemplateWithDefault &, T = f<T>());
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};
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void j(TemplateWithDefault &twd) {
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throw twd;
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}
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void h() {
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throw nullptr;
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}
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namespace std {
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template <typename T>
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void *__GetExceptionInfo(T);
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}
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using namespace std;
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void *GetExceptionInfo_test0() {
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// CHECK-LABEL: @"?GetExceptionInfo_test0@@YAPAXXZ"
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// CHECK: ret i8* bitcast (%eh.ThrowInfo* @_TI1H to i8*)
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return __GetExceptionInfo(0);
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}
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void *GetExceptionInfo_test1() {
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// CHECK-LABEL: @"?GetExceptionInfo_test1@@YAPAXXZ"
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// CHECK: ret i8* bitcast (%eh.ThrowInfo* @_TI1P6AXXZ to i8*)
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return __GetExceptionInfo<void (*)()>(&h);
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}
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// PR36327: Try an exception type with no linkage.
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namespace { struct Foo { } foo_exc; }
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void *GetExceptionInfo_test2() {
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// CHECK-LABEL: @"?GetExceptionInfo_test2@@YAPAXXZ"
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// CHECK: ret i8* bitcast (%eh.ThrowInfo* @"_TI1?AUFoo@?A0x{{[^@]*}}@@" to i8*)
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return __GetExceptionInfo(foo_exc);
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}
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