Revert Itanium parts of "Don't copy objects with trivial, deleted copy ctors"

This undoes half of r208786.

It had problems with lazily declared special members in cases like this:
  struct A {
    A();
    A &operator=(A &&o);
    void *p;
  };
  void foo(A);
  void bar() {
    foo({});
  }

In this case, the copy and move constructors are implicitly deleted.
However, Clang doesn't eagerly declare the copy ctor in the AST, so we
pass the struct in registers.  Furthermore, GCC passes this in registers
even though this class should be uncopyable.

Revert this for now until the dust settles.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208836 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGCXXABI.cpp b/lib/CodeGen/CGCXXABI.cpp
index 933fe2db2086ccbeabb96254757a01c10a023ad5..d1904ec7c4f5a51d803bdc27b7b51d75ce1bc2cf 100644 (file)
--- a/lib/CodeGen/CGCXXABI.cpp
+++ b/lib/CodeGen/CGCXXABI.cpp
@@ -42,7 +42,8 @@ bool CGCXXABI::canCopyArgument(const CXXRecordDecl *RD) const {
   // non-deleted copy or move constructor.
   // FIXME: This assumes that all lazily declared copy and move constructors are
   // not deleted.  This assumption might not be true in some corner cases.
-  bool CopyOrMoveDeleted = false;
+  bool CopyDeleted = false;
+  bool MoveDeleted = false;
   for (const CXXConstructorDecl *CD : RD->ctors()) {
     if (CD->isCopyConstructor() || CD->isMoveConstructor()) {
       assert(CD->isTrivial());
@@ -50,13 +51,16 @@ bool CGCXXABI::canCopyArgument(const CXXRecordDecl *RD) const {
       // directly.
       if (!CD->isDeleted())
         return true;
-      CopyOrMoveDeleted = true;
+      if (CD->isCopyConstructor())
+        CopyDeleted = true;
+      else
+        MoveDeleted = true;
     }
   }
 
   // If all trivial copy and move constructors are deleted, we cannot copy the
   // argument.
-  return !CopyOrMoveDeleted;
+  return !(CopyDeleted && MoveDeleted);
 }
 
 llvm::Constant *CGCXXABI::GetBogusMemberPointer(QualType T) {

diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index e3605e1b9cbb7d7adcb75c550febcc2154086dbd..07a8d8a846037a589d16ae95a30aed06b69b8186 100644 (file)
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -55,8 +55,11 @@ public:
   bool classifyReturnType(CGFunctionInfo &FI) const override;
 
   RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override {
-    // If C++ prohibits us from making a copy, pass by address.
-    if (!canCopyArgument(RD))
+    // Structures with either a non-trivial destructor or a non-trivial
+    // copy constructor are always indirect.
+    // FIXME: Use canCopyArgument() when it is fixed to handle lazily declared
+    // special members.
+    if (RD->hasNonTrivialDestructor() || RD->hasNonTrivialCopyConstructor())
       return RAA_Indirect;
     return RAA_Default;
   }
@@ -761,8 +764,10 @@ bool ItaniumCXXABI::classifyReturnType(CGFunctionInfo &FI) const {
   if (!RD)
     return false;
 
-  // If C++ prohibits us from making a copy, return by address.
-  if (!canCopyArgument(RD)) {
+  // Return indirectly if we have a non-trivial copy ctor or non-trivial dtor.
+  // FIXME: Use canCopyArgument() when it is fixed to handle lazily declared
+  // special members.
+  if (RD->hasNonTrivialDestructor() || RD->hasNonTrivialCopyConstructor()) {
     FI.getReturnInfo() = ABIArgInfo::getIndirect(0, /*ByVal=*/false);
     return true;
   }

diff --git a/test/CodeGenCXX/uncopyable-args.cpp b/test/CodeGenCXX/uncopyable-args.cpp
index e2acc79d829ecfb6b5e9715ad151b0ce7b5687a0..77996f656e01054156f6c34cfd6a96ffb65c4dfd 100644 (file)
--- a/test/CodeGenCXX/uncopyable-args.cpp
+++ b/test/CodeGenCXX/uncopyable-args.cpp
@@ -52,11 +52,12 @@ void foo(A);
 void bar() {
   foo({});
 }
-// CHECK-LABEL: define void @_ZN9move_ctor3barEv()
-// CHECK: call void @_Z{{.*}}C1Ev(
-// CHECK-NOT: call
-// CHECK: call void @_ZN9move_ctor3fooENS_1AE(%"struct.move_ctor::A"* %{{.*}})
-// CHECK-LABEL: declare void @_ZN9move_ctor3fooENS_1AE(%"struct.move_ctor::A"*)
+// FIXME: The copy ctor is implicitly deleted.
+// CHECK-DISABLED-LABEL: define void @_ZN9move_ctor3barEv()
+// CHECK-DISABLED: call void @_Z{{.*}}C1Ev(
+// CHECK-DISABLED-NOT: call
+// CHECK-DISABLED: call void @_ZN9move_ctor3fooENS_1AE(%"struct.move_ctor::A"* %{{.*}})
+// CHECK-DISABLED-LABEL: declare void @_ZN9move_ctor3fooENS_1AE(%"struct.move_ctor::A"*)
 
 // WIN64-LABEL: declare void @"\01?foo@move_ctor@@YAXUA@1@@Z"(%"struct.move_ctor::A"*)
 }
@@ -72,11 +73,12 @@ void foo(A);
 void bar() {
   foo({});
 }
-// CHECK-LABEL: define void @_ZN11all_deleted3barEv()
-// CHECK: call void @_Z{{.*}}C1Ev(
-// CHECK-NOT call
-// CHECK: call void @_ZN11all_deleted3fooENS_1AE(%"struct.all_deleted::A"* %{{.*}})
-// CHECK-LABEL: declare void @_ZN11all_deleted3fooENS_1AE(%"struct.all_deleted::A"*)
+// FIXME: The copy ctor is deleted.
+// CHECK-DISABLED-LABEL: define void @_ZN11all_deleted3barEv()
+// CHECK-DISABLED: call void @_Z{{.*}}C1Ev(
+// CHECK-DISABLED-NOT call
+// CHECK-DISABLED: call void @_ZN11all_deleted3fooENS_1AE(%"struct.all_deleted::A"* %{{.*}})
+// CHECK-DISABLED-LABEL: declare void @_ZN11all_deleted3fooENS_1AE(%"struct.all_deleted::A"*)
 
 // WIN64-LABEL: declare void @"\01?foo@all_deleted@@YAXUA@1@@Z"(%"struct.all_deleted::A"*)
 }
@@ -91,11 +93,12 @@ void foo(A);
 void bar() {
   foo({});
 }
-// CHECK-LABEL: define void @_ZN18implicitly_deleted3barEv()
-// CHECK: call void @_Z{{.*}}C1Ev(
-// CHECK-NOT call
-// CHECK: call void @_ZN18implicitly_deleted3fooENS_1AE(%"struct.implicitly_deleted::A"* %{{.*}})
-// CHECK-LABEL: declare void @_ZN18implicitly_deleted3fooENS_1AE(%"struct.implicitly_deleted::A"*)
+// FIXME: The copy and move ctors are implicitly deleted.
+// CHECK-DISABLED-LABEL: define void @_ZN18implicitly_deleted3barEv()
+// CHECK-DISABLED: call void @_Z{{.*}}C1Ev(
+// CHECK-DISABLED-NOT call
+// CHECK-DISABLED: call void @_ZN18implicitly_deleted3fooENS_1AE(%"struct.implicitly_deleted::A"* %{{.*}})
+// CHECK-DISABLED-LABEL: declare void @_ZN18implicitly_deleted3fooENS_1AE(%"struct.implicitly_deleted::A"*)
 
 // WIN64-LABEL: declare void @"\01?foo@implicitly_deleted@@YAXUA@1@@Z"(%"struct.implicitly_deleted::A"*)
 }
@@ -110,11 +113,12 @@ void foo(A);
 void bar() {
   foo({});
 }
-// CHECK-LABEL: define void @_ZN11one_deleted3barEv()
-// CHECK: call void @_Z{{.*}}C1Ev(
-// CHECK-NOT call
-// CHECK: call void @_ZN11one_deleted3fooENS_1AE(%"struct.one_deleted::A"* %{{.*}})
-// CHECK-LABEL: declare void @_ZN11one_deleted3fooENS_1AE(%"struct.one_deleted::A"*)
+// FIXME: The copy constructor is implicitly deleted.
+// CHECK-DISABLED-LABEL: define void @_ZN11one_deleted3barEv()
+// CHECK-DISABLED: call void @_Z{{.*}}C1Ev(
+// CHECK-DISABLED-NOT call
+// CHECK-DISABLED: call void @_ZN11one_deleted3fooENS_1AE(%"struct.one_deleted::A"* %{{.*}})
+// CHECK-DISABLED-LABEL: declare void @_ZN11one_deleted3fooENS_1AE(%"struct.one_deleted::A"*)
 
 // WIN64-LABEL: declare void @"\01?foo@one_deleted@@YAXUA@1@@Z"(%"struct.one_deleted::A"*)
 }
@@ -191,10 +195,12 @@ void foo(B);
 void bar() {
   foo({});
 }
-// CHECK-LABEL: define void @_ZN14two_copy_ctors3barEv()
-// CHECK: call void @_Z{{.*}}C1Ev(
-// CHECK: call void @_ZN14two_copy_ctors3fooENS_1BE(%"struct.two_copy_ctors::B"* %{{.*}})
-// CHECK-LABEL: declare void @_ZN14two_copy_ctors3fooENS_1BE(%"struct.two_copy_ctors::B"*)
+// FIXME: This class has a non-trivial copy ctor and a trivial copy ctor.  It's
+// not clear whether we should pass by address or in registers.
+// CHECK-DISABLED-LABEL: define void @_ZN14two_copy_ctors3barEv()
+// CHECK-DISABLED: call void @_Z{{.*}}C1Ev(
+// CHECK-DISABLED: call void @_ZN14two_copy_ctors3fooENS_1BE(%"struct.two_copy_ctors::B"* %{{.*}})
+// CHECK-DISABLED-LABEL: declare void @_ZN14two_copy_ctors3fooENS_1BE(%"struct.two_copy_ctors::B"*)
 
 // WIN64-LABEL: declare void @"\01?foo@two_copy_ctors@@YAXUB@1@@Z"(%"struct.two_copy_ctors::B"*)
 }