Add a new expression kind, OpaqueValueExpr, which is useful for
certain internal type-checking procedures as well as for representing
certain implicitly-generated operations.  Uses to follow.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119289 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index d6c6bf6..6ae334e 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -2709,3 +2709,9 @@
 
 Stmt::child_iterator BlockDeclRefExpr::child_begin() { return child_iterator();}
 Stmt::child_iterator BlockDeclRefExpr::child_end() { return child_iterator(); }
+
+// OpaqueValueExpr
+SourceRange OpaqueValueExpr::getSourceRange() const { return SourceRange(); }
+Stmt::child_iterator OpaqueValueExpr::child_begin() { return child_iterator(); }
+Stmt::child_iterator OpaqueValueExpr::child_end() { return child_iterator(); }
+
diff --git a/lib/AST/ExprClassification.cpp b/lib/AST/ExprClassification.cpp
index 0ab1402..1daa475 100644
--- a/lib/AST/ExprClassification.cpp
+++ b/lib/AST/ExprClassification.cpp
@@ -33,6 +33,22 @@
 static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E,
                                        Cl::Kinds Kind, SourceLocation &Loc);
 
+static Cl::Kinds ClassifyExprValueKind(const LangOptions &Lang,
+                                       const Expr *E,
+                                       ExprValueKind Kind) {
+  switch (Kind) {
+  case VK_RValue:
+    return Lang.CPlusPlus && E->getType()->isRecordType() ?
+      Cl::CL_ClassTemporary : Cl::CL_PRValue;
+  case VK_LValue:
+    return Cl::CL_LValue;
+  case VK_XValue:
+    return Cl::CL_XValue;
+  }
+  llvm_unreachable("Invalid value category of implicit cast.");
+  return Cl::CL_PRValue;
+}
+
 Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const {
   assert(!TR->isReferenceType() && "Expressions can't have reference type.");
 
@@ -171,19 +187,15 @@
       return Cl::CL_PRValue;
     }
 
+  case Expr::OpaqueValueExprClass:
+    return ClassifyExprValueKind(Lang, E,
+                                 cast<OpaqueValueExpr>(E)->getValueKind());
+
     // Implicit casts are lvalues if they're lvalue casts. Other than that, we
     // only specifically record class temporaries.
   case Expr::ImplicitCastExprClass:
-    switch (cast<ImplicitCastExpr>(E)->getValueKind()) {
-    case VK_RValue:
-      return Lang.CPlusPlus && E->getType()->isRecordType() ?
-        Cl::CL_ClassTemporary : Cl::CL_PRValue;
-    case VK_LValue:
-      return Cl::CL_LValue;
-    case VK_XValue:
-      return Cl::CL_XValue;
-    }
-    llvm_unreachable("Invalid value category of implicit cast.");
+    return ClassifyExprValueKind(Lang, E,
+                                 cast<ImplicitCastExpr>(E)->getValueKind());
 
     // C++ [expr.prim.general]p4: The presence of parentheses does not affect
     //   whether the expression is an lvalue.
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 8a6d4ba..d0b4c31 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -2541,6 +2541,7 @@
   case Expr::BlockExprClass:
   case Expr::BlockDeclRefExprClass:
   case Expr::NoStmtClass:
+  case Expr::OpaqueValueExprClass:
     return ICEDiag(2, E->getLocStart());
 
   case Expr::GNUNullExprClass:
diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index 270c9e1..d4791bc 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -1335,6 +1335,9 @@
 void StmtPrinter::VisitBlockDeclRefExpr(BlockDeclRefExpr *Node) {
   OS << Node->getDecl();
 }
+
+void StmtPrinter::VisitOpaqueValueExpr(OpaqueValueExpr *Node) {}
+
 //===----------------------------------------------------------------------===//
 // Stmt method implementations
 //===----------------------------------------------------------------------===//
diff --git a/lib/AST/StmtProfile.cpp b/lib/AST/StmtProfile.cpp
index 3f17a2b..d67f5fa 100644
--- a/lib/AST/StmtProfile.cpp
+++ b/lib/AST/StmtProfile.cpp
@@ -834,6 +834,10 @@
   VisitExpr(S);
 }
 
+void StmtProfiler::VisitOpaqueValueExpr(OpaqueValueExpr *E) {
+  VisitExpr(E);  
+}
+
 void StmtProfiler::VisitObjCStringLiteral(ObjCStringLiteral *S) {
   VisitExpr(S);
 }
diff --git a/lib/Checker/GRExprEngine.cpp b/lib/Checker/GRExprEngine.cpp
index ecf2103..d5c9ffa 100644
--- a/lib/Checker/GRExprEngine.cpp
+++ b/lib/Checker/GRExprEngine.cpp
@@ -744,6 +744,7 @@
     case Stmt::NoStmtClass:
     case Stmt::NullStmtClass:
     case Stmt::SwitchCaseClass:
+    case Stmt::OpaqueValueExprClass:
       llvm_unreachable("Stmt should not be in analyzer evaluation loop");
       break;
 
diff --git a/lib/CodeGen/Mangle.cpp b/lib/CodeGen/Mangle.cpp
index 1b7cfa1..83d43eb 100644
--- a/lib/CodeGen/Mangle.cpp
+++ b/lib/CodeGen/Mangle.cpp
@@ -1681,6 +1681,9 @@
     break;
   }
 
+  case Expr::OpaqueValueExprClass:
+    llvm_unreachable("cannot mangle opaque value; mangling wrong thing?");
+
   case Expr::CXXDefaultArgExprClass:
     mangleExpression(cast<CXXDefaultArgExpr>(E)->getExpr(), Arity);
     break;
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 12192c9..bae703d 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -4444,6 +4444,14 @@
 
 template<typename Derived>
 ExprResult
+TreeTransform<Derived>::TransformOpaqueValueExpr(OpaqueValueExpr *E) {
+  assert(getDerived().AlreadyTransformed(E->getType()) &&
+         "opaque value expression requires transformation");
+  return SemaRef.Owned(E);
+}
+
+template<typename Derived>
+ExprResult
 TreeTransform<Derived>::TransformSizeOfAlignOfExpr(SizeOfAlignOfExpr *E) {
   if (E->isArgumentType()) {
     TypeSourceInfo *OldT = E->getArgumentTypeInfo();
diff --git a/lib/Serialization/ASTReaderStmt.cpp b/lib/Serialization/ASTReaderStmt.cpp
index 41386dc..26077c5 100644
--- a/lib/Serialization/ASTReaderStmt.cpp
+++ b/lib/Serialization/ASTReaderStmt.cpp
@@ -178,6 +178,8 @@
 
     void VisitUnaryTypeTraitExpr(UnaryTypeTraitExpr *E);
     void VisitCXXNoexceptExpr(CXXNoexceptExpr *E);
+
+    void VisitOpaqueValueExpr(OpaqueValueExpr *E);
   };
 }
 
@@ -1280,6 +1282,11 @@
   E->Operand = Reader.ReadSubExpr();
 }
 
+void ASTStmtReader::VisitOpaqueValueExpr(OpaqueValueExpr *E) {
+  VisitExpr(E);
+  E->setValueKind(static_cast<ExprValueKind>(Record[Idx++]));
+}
+
 Stmt *ASTReader::ReadStmt(PerFileData &F) {
   switch (ReadingKind) {
   case Read_Decl:
@@ -1795,6 +1802,10 @@
     case EXPR_CXX_NOEXCEPT:
       S = new (Context) CXXNoexceptExpr(Empty);
       break;
+
+    case EXPR_OPAQUE_VALUE:
+      S = new (Context) OpaqueValueExpr(Empty);
+      break;
     }
     
     // We hit a STMT_STOP, so we're done with this expression.
diff --git a/lib/Serialization/ASTWriterStmt.cpp b/lib/Serialization/ASTWriterStmt.cpp
index fc8e9e0..efbfd94 100644
--- a/lib/Serialization/ASTWriterStmt.cpp
+++ b/lib/Serialization/ASTWriterStmt.cpp
@@ -152,6 +152,8 @@
 
     void VisitUnaryTypeTraitExpr(UnaryTypeTraitExpr *E);
     void VisitCXXNoexceptExpr(CXXNoexceptExpr *E);
+
+    void VisitOpaqueValueExpr(OpaqueValueExpr *E);
   };
 }
 
@@ -1293,6 +1295,12 @@
   Code = serialization::EXPR_CXX_NOEXCEPT;
 }
 
+void ASTStmtWriter::VisitOpaqueValueExpr(OpaqueValueExpr *E) {
+  VisitExpr(E);
+  Record.push_back(E->getValueKind());
+  Code = serialization::EXPR_OPAQUE_VALUE;
+}
+
 //===----------------------------------------------------------------------===//
 // ASTWriter Implementation
 //===----------------------------------------------------------------------===//