Extend the self move warning to record types.

Move the logic for checking self moves into SemaChecking and add that function
to Sema since it is now used in multiple places.

llvm-svn: 225756

5 files changed, 116 insertions, 86 deletions

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 95fc68fbc13..2ba74b12f6f 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -3326,6 +3326,10 @@ public:
   void DiagnoseEmptyLoopBody(const Stmt *S,
                              const Stmt *PossibleBody);
 
+  /// Warn if a value is moved to itself.
+  void DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
+                        SourceLocation OpLoc);
+
   ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
     return DelayedDiagnostics.push(pool);
   }
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index d14549c9e8c..9fc2bec23b1 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -8325,6 +8325,96 @@ void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
   }
 }
 
+//===--- CHECK: Warn on self move with std::move. -------------------------===//
+
+/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
+void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr,
+                             SourceLocation OpLoc) {
+
+  if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc))
+    return;
+
+  if (!ActiveTemplateInstantiations.empty())
+    return;
+
+  // Strip parens and casts away.
+  LHSExpr = LHSExpr->IgnoreParenImpCasts();
+  RHSExpr = RHSExpr->IgnoreParenImpCasts();
+
+  // Check for a call expression
+  const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr);
+  if (!CE || CE->getNumArgs() != 1)
+    return;
+
+  // Check for a call to std::move
+  const FunctionDecl *FD = CE->getDirectCallee();
+  if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() ||
+      !FD->getIdentifier()->isStr("move"))
+    return;
+
+  // Get argument from std::move
+  RHSExpr = CE->getArg(0);
+
+  const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr);
+  const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr);
+
+  // Two DeclRefExpr's, check that the decls are the same.
+  if (LHSDeclRef && RHSDeclRef) {
+    if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
+      return;
+    if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
+        RHSDeclRef->getDecl()->getCanonicalDecl())
+      return;
+
+    Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
+                                        << LHSExpr->getSourceRange()
+                                        << RHSExpr->getSourceRange();
+    return;
+  }
+
+  // Member variables require a different approach to check for self moves.
+  // MemberExpr's are the same if every nested MemberExpr refers to the same
+  // Decl and that the base Expr's are DeclRefExpr's with the same Decl or
+  // the base Expr's are CXXThisExpr's.
+  const Expr *LHSBase = LHSExpr;
+  const Expr *RHSBase = RHSExpr;
+  const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr);
+  const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr);
+  if (!LHSME || !RHSME)
+    return;
+
+  while (LHSME && RHSME) {
+    if (LHSME->getMemberDecl()->getCanonicalDecl() !=
+        RHSME->getMemberDecl()->getCanonicalDecl())
+      return;
+
+    LHSBase = LHSME->getBase();
+    RHSBase = RHSME->getBase();
+    LHSME = dyn_cast<MemberExpr>(LHSBase);
+    RHSME = dyn_cast<MemberExpr>(RHSBase);
+  }
+
+  LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase);
+  RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase);
+  if (LHSDeclRef && RHSDeclRef) {
+    if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
+      return;
+    if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
+        RHSDeclRef->getDecl()->getCanonicalDecl())
+      return;
+
+    Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
+                                        << LHSExpr->getSourceRange()
+                                        << RHSExpr->getSourceRange();
+    return;
+  }
+
+  if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase))
+    Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
+                                        << LHSExpr->getSourceRange()
+                                        << RHSExpr->getSourceRange();
+}
+
 //===--- Layout compatibility ----------------------------------------------//
 
 namespace {
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index cd953ab8986..59efbc1bb6a 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -9380,90 +9380,6 @@ static inline UnaryOperatorKind ConvertTokenKindToUnaryOpcode(
   return Opc;
 }
 
-/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
-static void DiagnoseSelfMove(Sema &S, const Expr *LHSExpr, const Expr *RHSExpr,
-                             SourceLocation OpLoc) {
-  if (!S.ActiveTemplateInstantiations.empty())
-    return;
-
-  // Strip parens and casts away.
-  LHSExpr = LHSExpr->IgnoreParenImpCasts();
-  RHSExpr = RHSExpr->IgnoreParenImpCasts();
-
-  // Check for a call expression
-  const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr);
-  if (!CE || CE->getNumArgs() != 1)
-    return;
-
-  // Check for a call to std::move
-  const FunctionDecl *FD = CE->getDirectCallee();
-  if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() ||
-      !FD->getIdentifier()->isStr("move"))
-    return;
-
-  // Get argument from std::move
-  RHSExpr = CE->getArg(0);
-
-  const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr);
-  const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr);
-
-  // Two DeclRefExpr's, check that the decls are the same.
-  if (LHSDeclRef && RHSDeclRef) {
-    if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
-      return;
-    if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
-        RHSDeclRef->getDecl()->getCanonicalDecl())
-      return;
-
-    S.Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
-                                        << LHSExpr->getSourceRange()
-                                        << RHSExpr->getSourceRange();
-    return;
-  }
-
-  // Member variables require a different approach to check for self moves.
-  // MemberExpr's are the same if every nested MemberExpr refers to the same
-  // Decl and that the base Expr's are DeclRefExpr's with the same Decl or
-  // the base Expr's are CXXThisExpr's.
-  const Expr *LHSBase = LHSExpr;
-  const Expr *RHSBase = RHSExpr;
-  const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr);
-  const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr);
-  if (!LHSME || !RHSME)
-    return;
-
-  while (LHSME && RHSME) {
-    if (LHSME->getMemberDecl()->getCanonicalDecl() !=
-        RHSME->getMemberDecl()->getCanonicalDecl())
-      return;
-
-    LHSBase = LHSME->getBase();
-    RHSBase = RHSME->getBase();
-    LHSME = dyn_cast<MemberExpr>(LHSBase);
-    RHSME = dyn_cast<MemberExpr>(RHSBase);
-  }
-
-  LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase);
-  RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase);
-  if (LHSDeclRef && RHSDeclRef) {
-    if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl())
-      return;
-    if (LHSDeclRef->getDecl()->getCanonicalDecl() !=
-        RHSDeclRef->getDecl()->getCanonicalDecl())
-      return;
-
-    S.Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
-                                        << LHSExpr->getSourceRange()
-                                        << RHSExpr->getSourceRange();
-    return;
-  }
-
-  if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase))
-    S.Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType()
-                                        << LHSExpr->getSourceRange()
-                                        << RHSExpr->getSourceRange();
-}
-
 /// DiagnoseSelfAssignment - Emits a warning if a value is assigned to itself.
 /// This warning is only emitted for builtin assignment operations. It is also
 /// suppressed in the event of macro expansions.
@@ -9593,7 +9509,7 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
     }
     if (!ResultTy.isNull()) {
       DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc);
-      DiagnoseSelfMove(*this, LHS.get(), RHS.get(), OpLoc);
+      DiagnoseSelfMove(LHS.get(), RHS.get(), OpLoc);
     }
     RecordModifiableNonNullParam(*this, LHS.get());
     break;
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 8341c008e82..9195ee59075 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -11199,7 +11199,12 @@ Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
         // Cut off the implicit 'this'.
         if (isa<CXXMethodDecl>(FnDecl))
           ArgsArray = ArgsArray.slice(1);
-        checkCall(FnDecl, ArgsArray, 0, isa<CXXMethodDecl>(FnDecl), OpLoc, 
+
+        // Check for a self move.
+        if (Op == OO_Equal)
+          DiagnoseSelfMove(Args[0], Args[1], OpLoc);
+
+        checkCall(FnDecl, ArgsArray, 0, isa<CXXMethodDecl>(FnDecl), OpLoc,
                   TheCall->getSourceRange(), VariadicDoesNotApply);
 
         return MaybeBindToTemporary(TheCall);
diff --git a/clang/test/SemaCXX/warn-self-move.cpp b/clang/test/SemaCXX/warn-self-move.cpp
index ae2dab1de10..23778c18711 100644
--- a/clang/test/SemaCXX/warn-self-move.cpp
+++ b/clang/test/SemaCXX/warn-self-move.cpp
@@ -38,3 +38,18 @@ class field_test {
     other.x = std::move(other.x);  // expected-warning{{explicitly moving}}
   }
 };
+
+struct A {};
+struct B { A a; };
+struct C { C() {}; ~C() {} };
+void struct_test() {
+  A a;
+  a = std::move(a);  // expected-warning{{explicitly moving}}
+
+  B b;
+  b = std::move(b);  // expected-warning{{explicitly moving}}
+  b.a = std::move(b.a);  // expected-warning{{explicitly moving}}
+
+  C c;
+  c = std::move(c);  // expected-warning{{explicitly moving}}
+}