[Sema] Add -Wno-self-assign-overloaded

Summary:
It seems there isn't much enthusiasm for `-wtest` D45685.

This is more conservative version, which i had in the very first
revision of D44883, but that 'erroneously' got removed because of the review.

**Based on some [irc] discussions, it must really be documented that
we want all the new diagnostics to have their own flags, to ease
rollouts, transitions, etc.**

Please do note that i'm only adding `-Wno-self-assign-overloaded`,
but not `-Wno-self-assign-field-overloaded`, because i'm honestly
not aware of any false-positives from the `-field` variant,
but i can just as easily add it if wanted.
https://reviews.llvm.org/D44883#1068561

Reviewers: dblaikie, aaron.ballman, thakis, rjmccall, rsmith

Reviewed By: dblaikie

Subscribers: Quuxplusone, chandlerc, cfe-commits

Differential Revision: https://reviews.llvm.org/D45766

llvm-svn: 330651

1 files changed, 8 insertions, 7 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index a9b85612288..b4d1eb0e0ce 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -11497,7 +11497,7 @@ static inline UnaryOperatorKind ConvertTokenKindToUnaryOpcode(
 /// DiagnoseSelfAssignment - Emits a warning if a value is assigned to itself.
 /// This warning suppressed in the event of macro expansions.
 static void DiagnoseSelfAssignment(Sema &S, Expr *LHSExpr, Expr *RHSExpr,
-                                   SourceLocation OpLoc) {
+                                   SourceLocation OpLoc, bool IsBuiltin) {
   if (S.inTemplateInstantiation())
     return;
   if (S.isUnevaluatedContext())
@@ -11524,9 +11524,10 @@ static void DiagnoseSelfAssignment(Sema &S, Expr *LHSExpr, Expr *RHSExpr,
     if (RefTy->getPointeeType().isVolatileQualified())
       return;
 
-  S.Diag(OpLoc, diag::warn_self_assignment)
-      << LHSDeclRef->getType()
-      << LHSExpr->getSourceRange() << RHSExpr->getSourceRange();
+  S.Diag(OpLoc, IsBuiltin ? diag::warn_self_assignment_builtin
+                          : diag::warn_self_assignment_overloaded)
+      << LHSDeclRef->getType() << LHSExpr->getSourceRange()
+      << RHSExpr->getSourceRange();
 }
 
 /// Check if a bitwise-& is performed on an Objective-C pointer.  This
@@ -11719,7 +11720,7 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
       OK = LHS.get()->getObjectKind();
     }
     if (!ResultTy.isNull()) {
-      DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc);
+      DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc, true);
       DiagnoseSelfMove(LHS.get(), RHS.get(), OpLoc);
     }
     RecordModifiableNonNullParam(*this, LHS.get());
@@ -11817,7 +11818,7 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
     break;
   case BO_AndAssign:
   case BO_OrAssign: // fallthrough
-    DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc);
+    DiagnoseSelfAssignment(*this, LHS.get(), RHS.get(), OpLoc, true);
     LLVM_FALLTHROUGH;
   case BO_XorAssign:
     CompResultTy = CheckBitwiseOperands(LHS, RHS, OpLoc, Opc);
@@ -12124,7 +12125,7 @@ static ExprResult BuildOverloadedBinOp(Sema &S, Scope *Sc, SourceLocation OpLoc,
   case BO_AndAssign:
   case BO_OrAssign:
   case BO_XorAssign:
-    DiagnoseSelfAssignment(S, LHS, RHS, OpLoc);
+    DiagnoseSelfAssignment(S, LHS, RHS, OpLoc, false);
     CheckIdentityFieldAssignment(LHS, RHS, OpLoc, S);
     break;
   default: