1 files changed, 27 insertions, 25 deletions

diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 0a3cc306657..409bad72ee5 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -819,44 +819,46 @@ MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
     return RAA_Default;
 
   case llvm::Triple::x86_64:
-    // If a class has a destructor, we'd really like to pass it indirectly
+    // Win64 passes objects with non-trivial copy ctors indirectly.
+    if (RD->hasNonTrivialCopyConstructor())
+      return RAA_Indirect;
+
+    // If an object has a destructor, we'd really like to pass it indirectly
     // because it allows us to elide copies.  Unfortunately, MSVC makes that
     // impossible for small types, which it will pass in a single register or
     // stack slot. Most objects with dtors are large-ish, so handle that early.
     // We can't call out all large objects as being indirect because there are
     // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
     // how we pass large POD types.
-    //
-    // Note: This permits small classes with nontrivial destructors to be
-    // passed in registers, which is non-conforming.
     if (RD->hasNonTrivialDestructor() &&
         getContext().getTypeSize(RD->getTypeForDecl()) > 64)
       return RAA_Indirect;
 
-    // If a class has at least one non-deleted, trivial copy constructor, it
-    // is passed according to the C ABI. Otherwise, it is passed indirectly.
-    //
-    // Note: This permits classes with non-trivial copy or move ctors to be
-    // passed in registers, so long as they *also* have a trivial copy ctor,
-    // which is non-conforming.
-    if (RD->needsImplicitCopyConstructor()) {
-      // If the copy ctor has not yet been declared, we can read its triviality
-      // off the AST.
-      if (!RD->defaultedCopyConstructorIsDeleted() &&
-          RD->hasTrivialCopyConstructor())
-        return RAA_Default;
-    } else {
-      // Otherwise, we need to find the copy constructor(s) and ask.
-      for (const CXXConstructorDecl *CD : RD->ctors()) {
-        if (CD->isCopyConstructor()) {
-          // We had at least one nondeleted trivial copy ctor.  Return directly.
-          if (!CD->isDeleted() && CD->isTrivial())
-            return RAA_Default;
-        }
+    // If this is true, the implicit copy constructor that Sema would have
+    // created would not be deleted. FIXME: We should provide a more direct way
+    // for CodeGen to ask whether the constructor was deleted.
+    if (!RD->hasUserDeclaredCopyConstructor() &&
+        !RD->hasUserDeclaredMoveConstructor() &&
+        !RD->needsOverloadResolutionForMoveConstructor() &&
+        !RD->hasUserDeclaredMoveAssignment() &&
+        !RD->needsOverloadResolutionForMoveAssignment())
+      return RAA_Default;
+
+    // Otherwise, Sema should have created an implicit copy constructor if
+    // needed.
+    assert(!RD->needsImplicitCopyConstructor());
+
+    // We have to make sure the trivial copy constructor isn't deleted.
+    for (const CXXConstructorDecl *CD : RD->ctors()) {
+      if (CD->isCopyConstructor()) {
+        assert(CD->isTrivial());
+        // We had at least one undeleted trivial copy ctor.  Return directly.
+        if (!CD->isDeleted())
+          return RAA_Default;
       }
     }
 
-    // We have no trivial, non-deleted copy constructor.
+    // The trivial copy constructor was deleted.  Return indirectly.
     return RAA_Indirect;
   }