[clang][ItaniumMangle] Mangle friend function templates with a constr… (#110247)

…aint that depends on a template parameter from an enclosing template as
members of the enclosing class.

Such function templates should be considered member-like constrained
friends per [temp.friend]p9 and
itanium-cxx-abi/cxx-abi#24 (comment)).

Author: VitaNuo

clang/docs/ReleaseNotes.rst

@@ -447,6 +447,7 @@ Bug Fixes to C++ Support
 - Fixed an assertion failure in debug mode, and potential crashes in release mode, when
   diagnosing a failed cast caused indirectly by a failed implicit conversion to the type of the constructor parameter.
 - Fixed an assertion failure by adjusting integral to boolean vector conversions (#GH108326)
+- Mangle friend function templates with a constraint that depends on a template parameter from an enclosing template as members of the enclosing class. (#GH110247)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/AST/ItaniumMangle.cpp

@@ -693,7 +693,7 @@ ItaniumMangleContextImpl::getEffectiveDeclContext(const Decl *D) {
     if (VD->isExternC())
       return getASTContext().getTranslationUnitDecl();
 
-  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+  if (const auto *FD = D->getAsFunction()) {
     if (FD->isExternC())
       return getASTContext().getTranslationUnitDecl();
     // Member-like constrained friends are mangled as if they were members of

clang/test/CodeGenCXX/mangle-concept.cpp

@@ -52,30 +52,53 @@ namespace test2 {
   };
 
   A<int> ai;
+  A<bool> aj;
 
   // CHECK-LABEL: define {{.*}}@{{.*}}test2{{.*}}use
   void use() {
     // CHECK: call {{.*}}@_ZN5test21AIiEF1fEzQ4TrueIT_E(
     // CLANG17: call {{.*}}@_ZN5test21fEz(
     f(ai);
-    // CHECK: call {{.*}}@_ZN5test2F1gIvEEvzQaa4TrueIT_E4TrueITL0__E(
+    // CHECK: call {{.*}}@_ZN5test21AIiEF1gIvEEvzQaa4TrueIT_E4TrueITL0__E(
     // CLANG17: call {{.*}}@_ZN5test21gIvEEvz(
     g(ai);
     // CHECK: call {{.*}}@_ZN5test21hIvEEvzQ4TrueITL0__E(
     // CLANG17: call {{.*}}@_ZN5test21hIvEEvz(
     h(ai);
-    // CHECK: call {{.*}}@_ZN5test2F1iIvQaa4TrueIT_E4TrueITL0__EEEvz(
+    // CHECK: call {{.*}}@_ZN5test21AIiEF1iIvQaa4TrueIT_E4TrueITL0__EEEvz(
     // CLANG17: call {{.*}}@_ZN5test21iIvEEvz(
     i(ai);
     // CHECK: call {{.*}}@_ZN5test21jIvQ4TrueITL0__EEEvz(
     // CLANG17: call {{.*}}@_ZN5test21jIvEEvz(
     j(ai);
-    // CHECK: call {{.*}}@_ZN5test2F1kITk4TruevQ4TrueIT_EEEvz(
+    // CHECK: call {{.*}}@_ZN5test21AIiEF1kITk4TruevQ4TrueIT_EEEvz(
     // CLANG17: call {{.*}}@_ZN5test21kIvEEvz(
     k(ai);
     // CHECK: call {{.*}}@_ZN5test21lITk4TruevEEvz(
     // CLANG17: call {{.*}}@_ZN5test21lIvEEvz(
     l(ai);
+
+    // CHECK: call {{.*}}@_ZN5test21AIbEF1fEzQ4TrueIT_E(
+    // CLANG17: call {{.*}}@_ZN5test21fEz(
+    f(aj);
+    // CHECK: call {{.*}}@_ZN5test21AIbEF1gIvEEvzQaa4TrueIT_E4TrueITL0__E(
+    // CLANG17: call {{.*}}@_ZN5test21gIvEEvz(
+    g(aj);
+    // CHECK: call {{.*}}@_ZN5test21hIvEEvzQ4TrueITL0__E(
+    // CLANG17: call {{.*}}@_ZN5test21hIvEEvz(
+    h(aj);
+    // CHECK: call {{.*}}@_ZN5test21AIbEF1iIvQaa4TrueIT_E4TrueITL0__EEEvz(
+    // CLANG17: call {{.*}}@_ZN5test21iIvEEvz(
+    i(aj);
+    // CHECK: call {{.*}}@_ZN5test21jIvQ4TrueITL0__EEEvz(
+    // CLANG17: call {{.*}}@_ZN5test21jIvEEvz(
+    j(aj);
+    // CHECK: call {{.*}}@_ZN5test21AIbEF1kITk4TruevQ4TrueIT_EEEvz(
+    // CLANG17: call {{.*}}@_ZN5test21kIvEEvz(
+    k(aj);
+    // CHECK: call {{.*}}@_ZN5test21lITk4TruevEEvz(
+    // CLANG17: call {{.*}}@_ZN5test21lIvEEvz(
+    l(aj);
   }
 }
 

libcxxabi/test/test_demangle.pass.cpp

@@ -30128,11 +30128,15 @@ const char* cases[][2] =
     // C++20 concepts, see https://github.com/itanium-cxx-abi/cxx-abi/issues/24.
     {"_Z2f0IiE1SIX1CIT_EEEv", "S<C<int>> f0<int>()"},
     {"_ZN5test21AIiEF1fEzQ4TrueIT_E", "test2::A<int>::friend f(...) requires True<T>"},
-    {"_ZN5test2F1gIvEEvzQaa4TrueIT_E4TrueITL0__E", "void test2::friend g<void>(...) requires True<T> && True<TL0_>"},
+    {"_ZN5test21AIbEF1fEzQ4TrueIT_E", "test2::A<bool>::friend f(...) requires True<T>"},
+    {"_ZN5test21AIiEF1gIvEEvzQaa4TrueIT_E4TrueITL0__E", "void test2::A<int>::friend g<void>(...) requires True<T> && True<TL0_>"},
+    {"_ZN5test21AIbEF1gIvEEvzQaa4TrueIT_E4TrueITL0__E", "void test2::A<bool>::friend g<void>(...) requires True<T> && True<TL0_>"},
     {"_ZN5test21hIvEEvzQ4TrueITL0__E", "void test2::h<void>(...) requires True<TL0_>"},
-    {"_ZN5test2F1iIvQaa4TrueIT_E4TrueITL0__EEEvz", "void test2::friend i<void>(...)"},
+    {"_ZN5test21AIiEF1iIvQaa4TrueIT_E4TrueITL0__EEEvz", "void test2::A<int>::friend i<void>(...)"},
+    {"_ZN5test21AIbEF1iIvQaa4TrueIT_E4TrueITL0__EEEvz", "void test2::A<bool>::friend i<void>(...)"},
     {"_ZN5test21jIvQ4TrueITL0__EEEvz", "void test2::j<void>(...)"},
-    {"_ZN5test2F1kITk4TruevQ4TrueIT_EEEvz", "void test2::friend k<void>(...)"},
+    {"_ZN5test21AIiEF1kITk4TruevQ4TrueIT_EEEvz", "void test2::A<int>::friend k<void>(...)"},
+    {"_ZN5test21AIbEF1kITk4TruevQ4TrueIT_EEEvz", "void test2::A<bool>::friend k<void>(...)"},
     {"_ZN5test21lITk4TruevEEvz", "void test2::l<void>(...)"},
     {"_ZN5test31dITnDaLi0EEEvv", "void test3::d<0>()"},
     {"_ZN5test31eITnDcLi0EEEvv", "void test3::e<0>()"},