Fix #4779 - C++ classes need TypeInfo

Author: rikkimax

gen/typinf.cpp

@@ -506,8 +506,19 @@ class DeclareOrDefineVisitor : public Visitor {
     auto cd = decl->tinfo->isTypeClass()->sym;
     DtoResolveClass(cd);
 
+    auto irclass = getIrAggr(cd, true);
     IrGlobal *irg = getIrGlobal(decl, true);
-    irg->value = getIrAggr(cd)->getClassInfoSymbol();
+    
+    auto ti = irclass->getClassInfoSymbol();
+    irg->value = ti;
+    
+    // check if the definition can be elided
+    if (irclass->suppressTypeInfo()) {
+        return;
+    }
+    
+    irclass->getClassInfoSymbol(true);
+    ti->setLinkage(TYPEINFO_LINKAGE_TYPE); // override
   }
 
   // Build all other TypeInfos.

ir/irclass.cpp

@@ -29,6 +29,7 @@
 #include "gen/runtime.h"
 #include "gen/tollvm.h"
 #include "gen/typinf.h"
+#include "gen/linkage.h"
 #include "ir/iraggr.h"
 #include "ir/irdsymbol.h"
 #include "ir/irfunction.h"
@@ -391,7 +392,9 @@ LLConstant *IrClass::getClassInfoInit() {
   assert(!isInterface || !cd->baseClass);
   if (cd->baseClass) {
     DtoResolveClass(cd->baseClass);
-    b.push(getIrAggr(cd->baseClass)->getClassInfoSymbol());
+    auto ti = getIrAggr(cd->baseClass)->getClassInfoSymbol(true);
+    ti->setLinkage(TYPEINFO_LINKAGE_TYPE); // override
+    b.push(ti);
   } else {
     b.push_null(cinfoType);
   }
@@ -772,6 +775,7 @@ LLConstant *IrClass::getClassInfoInterfaces() {
   LLConstant *arr = LLConstantArray::get(array_type, constants);
   auto ciarr = getInterfaceArraySymbol();
   defineGlobal(ciarr, arr, cd);
+  ciarr->setLinkage(TYPEINFO_LINKAGE_TYPE); // override
 
   // return null, only baseclass provide interfaces
   if (cd->vtblInterfaces->length == 0) {

tests/linking/inputs/typeinfo_on_demand2.d

@@ -0,0 +1,5 @@
+module inputs.typeinfo_on_demand2;
+
+extern(C++) class MyClass {
+    void method() {}
+}

tests/linking/typeinfo_on_demand.d

@@ -0,0 +1,14 @@
+// Tests that TypeInfo is generated per CU to enable on demand usage
+
+// RUN: %ldc -of%t_lib%obj -betterC -c %S/inputs/typeinfo_on_demand2.d
+// RUN: %ldc -I%S %t_lib%obj -run %s
+
+import inputs.typeinfo_on_demand2;
+
+void main() {
+  MyChildClass mcc = new MyChildClass;
+  mcc.method();
+}
+
+extern(C++) class MyChildClass : MyClass {
+}