Try harder to not inline dllimport functions referencing non-dllimport functions

In r246338, code was added to check for this, but it failed to take into
account implicit destructor invocations because those are not reflected
in the AST. This adds a separate check for them.

llvm-svn: 281395

clang/lib/CodeGen/CodeGenModule.cpp

@@ -1740,8 +1740,17 @@ CodeGenModule::isTriviallyRecursive(const FunctionDecl *FD) {
   return Walker.Result;
 }
 
-bool
-CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
+// Check if T is a class type with a destructor that's not dllimport.
+static bool HasNonDllImportDtor(QualType T) {
+  if (const RecordType *RT = dyn_cast<RecordType>(T))
+    if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
+      if (RD->getDestructor() && !RD->getDestructor()->hasAttr<DLLImportAttr>())
+        return true;
+
+  return false;
+}
+
+bool CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
   if (getFunctionLinkage(GD) != llvm::Function::AvailableExternallyLinkage)
     return true;
   const auto *F = cast<FunctionDecl>(GD.getDecl());
@@ -1754,6 +1763,18 @@ CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
     Visitor.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
     if (!Visitor.SafeToInline)
       return false;
+
+    if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(F)) {
+      // Implicit destructor invocations aren't captured in the AST, so the
+      // check above can't see them. Check for them manually here.
+      for (const Decl *Member : Dtor->getParent()->decls())
+        if (isa<FieldDecl>(Member))
+          if (HasNonDllImportDtor(cast<FieldDecl>(Member)->getType()))
+            return false;
+      for (const CXXBaseSpecifier &B : Dtor->getParent()->bases())
+        if (HasNonDllImportDtor(B.getType()))
+          return false;
+    }
   }
 
   // PR9614. Avoid cases where the source code is lying to us. An available

clang/test/CodeGenCXX/dllimport-members.cpp

@@ -44,7 +44,7 @@ void useSpecials() {
 }
 
 // Used to force non-trivial special members.
-struct ForceNonTrivial {
+struct __declspec(dllimport) ForceNonTrivial {
   ForceNonTrivial();
   ~ForceNonTrivial();
   ForceNonTrivial(const ForceNonTrivial&);

clang/test/CodeGenCXX/dllimport.cpp

@@ -347,6 +347,13 @@ __declspec(dllimport) inline int *ReferencingImportedDelete() { delete (int*)nul
 // MO1-DAG: define available_externally dllimport i32* @"\01?ReferencingImportedDelete@@YAPAHXZ"
 USE(ReferencingImportedNew)
 USE(ReferencingImportedDelete)
+struct ClassWithDtor { ~ClassWithDtor() {} };
+struct __declspec(dllimport) ClassWithNonDllImportField { ClassWithDtor t; };
+struct __declspec(dllimport) ClassWithNonDllImportBase : public ClassWithDtor { };
+USECLASS(ClassWithNonDllImportField);
+USECLASS(ClassWithNonDllImportBase);
+// MO1-DAG: declare dllimport x86_thiscallcc void @"\01??1ClassWithNonDllImportBase@@QAE@XZ"(%struct.ClassWithNonDllImportBase*)
+// MO1-DAG: declare dllimport x86_thiscallcc void @"\01??1ClassWithNonDllImportField@@QAE@XZ"(%struct.ClassWithNonDllImportField*)
 
 // A dllimport function with a TLS variable must not be available_externally.
 __declspec(dllimport) inline void FunctionWithTLSVar() { static __thread int x = 42; }