Fix handling of call via indirect reference

Author: andykaylor

clang/lib/CIR/CodeGen/CIRGenExpr.cpp

@@ -1821,9 +1821,11 @@ CIRGenCallee CIRGenFunction::emitCallee(const clang::Expr *e) {
     const auto *funcDecl = cast<FunctionDecl>(declRef->getDecl());
     return emitDirectCallee(funcDecl);
   } else if (auto me = dyn_cast<MemberExpr>(e)) {
-    const auto *fd = cast<FunctionDecl>(me->getMemberDecl());
-    emitIgnoredExpr(me->getBase());
-    return emitDirectCallee(fd);
+    if (const auto *fd = dyn_cast<FunctionDecl>(me->getMemberDecl())) {
+      emitIgnoredExpr(me->getBase());
+      return emitDirectCallee(fd);
+    }
+    // Else fall through to the indirect reference handling below.
   } else if (auto *pde = dyn_cast<CXXPseudoDestructorExpr>(e)) {
     return CIRGenCallee::forPseudoDestructor(pde);
   }

clang/test/CIR/CodeGen/call-via-class-member-funcptr.cpp

@@ -34,3 +34,53 @@ void fn1() { F f1; }
 // OGCG: define {{.*}} ptr @_ZN1F1bEv
 // OGCG:   %[[VAR_H:.*]] = load i32, ptr @h
 // OGCG:   %[[RET:.*]] = call noundef ptr @_ZN1A1bEi(i32 noundef %[[VAR_H]])
+
+class B {
+public:
+  B();
+  int (&indirect_callee_int_ref)(int);
+};
+
+class C {
+public:
+  int call_indirect(int v) { return inner.indirect_callee_int_ref(v); };
+  B inner;
+};
+
+void fn2() { C c1; c1.call_indirect(2); }
+
+// CIR: cir.func {{.*}} @_ZN1C13call_indirectEi(%[[THIS_ARG:.*]]: !cir.ptr<!rec_C> {{.*}}, %[[V_ARG:.*]]: !s32i {{.*}}) -> !s32i
+// CIR:   %[[THIS_ADDR:.*]] = cir.alloca !cir.ptr<!rec_C>, !cir.ptr<!cir.ptr<!rec_C>>, ["this", init]
+// CIR:   %[[V_ADDR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["v", init]
+// CIR:   cir.store %[[THIS_ARG]], %[[THIS_ADDR]]
+// CIR:   cir.store %[[V_ARG]], %[[V_ADDR]]
+// CIR:   %[[THIS:.*]] = cir.load %[[THIS_ADDR]]
+// CIR:   %[[INNER:.*]] = cir.get_member %[[THIS]][0] {name = "inner"} : !cir.ptr<!rec_C> -> !cir.ptr<!rec_B>
+// CIR:   %[[INDIRECT_CALLEE_PTR:.*]] = cir.get_member %[[INNER]][0] {name = "indirect_callee_int_ref"}
+// CIR:   %[[INDIRECT_CALLEE:.*]] = cir.load %[[INDIRECT_CALLEE_PTR]]
+// CIR:   %[[V:.*]] = cir.load{{.*}} %[[V_ADDR]] : !cir.ptr<!s32i>, !s32i
+// CIR:   %[[RET:.*]] = cir.call %[[INDIRECT_CALLEE]](%[[V]])
+
+// LLVM: define {{.*}} i32 @_ZN1C13call_indirectEi(ptr %[[THIS_ARG:.*]], i32 %[[V_ARG:.*]])
+// LLVM:   %[[THIS_ADDR:.*]] = alloca ptr
+// LLVM:   %[[V_ADDR:.*]] = alloca i32
+// LLVM:   store ptr %[[THIS_ARG]], ptr %[[THIS_ADDR]]
+// LLVM:   store i32 %[[V_ARG]], ptr %[[V_ADDR]]
+// LLVM:   %[[THIS:.*]] = load ptr, ptr %[[THIS_ADDR]]
+// LLVM:   %[[INNER:.*]] = getelementptr %class.C, ptr %[[THIS]], i32 0, i32 0
+// LLVM:   %[[INDIRECT_CALLEE_PTR:.*]] = getelementptr %class.B, ptr %[[INNER]], i32 0, i32 0
+// LLVM:   %[[INDIRECT_CALLEE:.*]] = load ptr, ptr %[[INDIRECT_CALLEE_PTR]]
+// LLVM:   %[[V:.*]] = load i32, ptr %[[V_ADDR]]
+// LLVM:   %[[RET:.*]] = call i32 %[[INDIRECT_CALLEE]](i32 %[[V]])
+
+// OGCG: define {{.*}} i32 @_ZN1C13call_indirectEi(ptr {{.*}} %[[THIS_ARG:.*]], i32 {{.*}} %[[V_ARG:.*]])
+// OGCG:   %[[THIS_ADDR:.*]] = alloca ptr
+// OGCG:   %[[V_ADDR:.*]] = alloca i32
+// OGCG:   store ptr %[[THIS_ARG]], ptr %[[THIS_ADDR]]
+// OGCG:   store i32 %[[V_ARG]], ptr %[[V_ADDR]]
+// OGCG:   %[[THIS:.*]] = load ptr, ptr %[[THIS_ADDR]]
+// OGCG:   %[[INNER:.*]] = getelementptr inbounds nuw %class.C, ptr %[[THIS]], i32 0, i32 0
+// OGCG:   %[[INDIRECT_CALLEE_PTR:.*]] = getelementptr inbounds nuw %class.B, ptr %[[INNER]], i32 0, i32 0
+// OGCG:   %[[INDIRECT_CALLEE:.*]] = load ptr, ptr %[[INDIRECT_CALLEE_PTR]]
+// OGCG:   %[[V:.*]] = load i32, ptr %[[V_ADDR]]
+// OGCG:   %[[RET:.*]] = call noundef i32 %[[INDIRECT_CALLEE]](i32 noundef %[[V]])