FinishThunk, and the invariant of setting and then unsetting
CurCodeDecl, was added in
7f416cc42638 (2015). The invariant didn't
exist when I added this musttail codepath in
ab2090d10765 (2014).
Recently in
28328c3771, I started using this codepath on non-Windows
platforms, and users reported problems during release testing (PR44987).
The issue was already present for users of EH on i686-windows-msvc, so I
added a test for that case as well.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D76444
// Finish the function to maintain CodeGenFunction invariants.
// FIXME: Don't emit unreachable code.
EmitBlock(createBasicBlock());
- FinishFunction();
+
+ FinishThunk();
}
void CodeGenFunction::generateThunk(llvm::Function *Fn,
CGM.SetLLVMFunctionAttributesForDefinition(GD.getDecl(), ThunkFn);
// Thunks for variadic methods are special because in general variadic
- // arguments cannot be perferctly forwarded. In the general case, clang
+ // arguments cannot be perfectly forwarded. In the general case, clang
// implements such thunks by cloning the original function body. However, for
// thunks with no return adjustment on targets that support musttail, we can
// use musttail to perfectly forward the variadic arguments.
--- /dev/null
+// RUN: %clang_cc1 -fexceptions -fcxx-exceptions %s -triple=i686-windows-msvc -emit-llvm -o - | FileCheck %s
+
+// When generating thunks using musttail due to inalloca parameters, don't push
+// and pop terminate scopes. PR44987
+
+struct NonTrivial {
+ NonTrivial();
+ NonTrivial(const NonTrivial &o);
+ ~NonTrivial();
+ int x;
+};
+struct A {
+ virtual void f(NonTrivial o) noexcept;
+};
+struct B {
+ virtual void f(NonTrivial o) noexcept;
+};
+class C : A, B {
+ virtual void f(NonTrivial o) noexcept;
+};
+C c;
+
+// CHECK-LABEL: define linkonce_odr dso_local x86_thiscallcc void @"?f@C@@G3AEXUNonTrivial@@@Z"(%class.C* %this, <{ %struct.NonTrivial }>* inalloca %0)
+// CHECK-NOT: invoke
+// CHECK: musttail call x86_thiscallcc void @"?f@C@@EAEXUNonTrivial@@@Z"(%class.C* %{{.*}}, <{ %struct.NonTrivial }>* inalloca %0)
+// CHECK-NEXT ret void
+
--- /dev/null
+// RUN: %clang_cc1 -fexceptions -fcxx-exceptions %s -triple=x86_64-pc-linux-gnu -munwind-tables -emit-llvm -o - -O1 -disable-llvm-passes | FileCheck %s
+
+// When generating the thunk for secondary, do not push terminate scopes for
+// either the varargs or non-varargs case. Related to PR44987.
+
+struct A {
+ virtual void primary_key();
+};
+struct B {
+ virtual void secondary();
+ virtual void secondary_vararg(int, ...);
+};
+class C : A, B {
+ virtual void primary_key();
+ void secondary() noexcept;
+ void secondary_vararg(int, ...) noexcept;
+};
+void C::primary_key() {}
+
+// CHECK-LABEL: define available_externally void @_ZThn8_N1C9secondaryEv(%class.C* %this)
+// CHECK-NOT: invoke
+// CHECK: tail call void @_ZN1C9secondaryEv(%class.C* %{{.*}})
+// CHECK-NOT: invoke
+// CHECK: ret void
+
+// CHECK-LABEL: define available_externally void @_ZThn8_N1C16secondary_varargEiz(%class.C* %this, i32 %0, ...)
+// CHECK-NOT: invoke
+// CHECK: musttail call void (%class.C*, i32, ...) @_ZN1C16secondary_varargEiz(%class.C* %{{.*}}, i32 %{{.*}}, ...) #2
+// CHECK-NEXT: ret void