Create ConstantExpr class

A ConstantExpr class represents a full expression that's in a context where a
constant expression is required. This class reflects the path the evaluator
took to reach the expression rather than the syntactic context in which the
expression occurs.

In the future, the class will be expanded to cache the result of the evaluated
expression so that it's not needlessly re-evaluated

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D53475


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@345692 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/AST/Expr.h

@@ -868,6 +868,64 @@ public:
   }
 };
 
+//===----------------------------------------------------------------------===//
+// Wrapper Expressions.
+//===----------------------------------------------------------------------===//
+
+/// FullExpr - Represents a "full-expression" node.
+class FullExpr : public Expr {
+protected:
+ Stmt *SubExpr;
+
+ FullExpr(StmtClass SC, Expr *subexpr)
+    : Expr(SC, subexpr->getType(),
+           subexpr->getValueKind(), subexpr->getObjectKind(),
+           subexpr->isTypeDependent(), subexpr->isValueDependent(),
+           subexpr->isInstantiationDependent(),
+           subexpr->containsUnexpandedParameterPack()), SubExpr(subexpr) {}
+  FullExpr(StmtClass SC, EmptyShell Empty)
+    : Expr(SC, Empty) {}
+public:
+  const Expr *getSubExpr() const { return cast<Expr>(SubExpr); }
+  Expr *getSubExpr() { return cast<Expr>(SubExpr); }
+
+  /// As with any mutator of the AST, be very careful when modifying an
+  /// existing AST to preserve its invariants.
+  void setSubExpr(Expr *E) { SubExpr = E; }
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() >= firstFullExprConstant &&
+           T->getStmtClass() <= lastFullExprConstant;
+  }
+};
+
+/// ConstantExpr - An expression that occurs in a constant context.
+struct ConstantExpr : public FullExpr {
+  ConstantExpr(Expr *subexpr)
+    : FullExpr(ConstantExprClass, subexpr) {}
+
+  /// Build an empty constant expression wrapper.
+  explicit ConstantExpr(EmptyShell Empty)
+    : FullExpr(ConstantExprClass, Empty) {}
+
+  SourceLocation getBeginLoc() const LLVM_READONLY {
+    return SubExpr->getBeginLoc();
+  }
+  SourceLocation getEndLoc() const LLVM_READONLY {
+    return SubExpr->getEndLoc();
+  }
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == ConstantExprClass;
+  }
+
+  // Iterators
+  child_range children() { return child_range(&SubExpr, &SubExpr+1); }
+  const_child_range children() const {
+    return const_child_range(&SubExpr, &SubExpr + 1);
+  }
+};
+
 //===----------------------------------------------------------------------===//
 // Primary Expressions.
 //===----------------------------------------------------------------------===//

include/clang/AST/ExprCXX.h

@@ -3031,7 +3031,7 @@ public:
 /// potentially-evaluated block literal.  The lifetime of a block
 /// literal is the extent of the enclosing scope.
 class ExprWithCleanups final
-    : public Expr,
+    : public FullExpr,
       private llvm::TrailingObjects<ExprWithCleanups, BlockDecl *> {
 public:
   /// The type of objects that are kept in the cleanup.
@@ -3044,8 +3044,6 @@ private:
   friend class ASTStmtReader;
   friend TrailingObjects;
 
-  Stmt *SubExpr;
-
   ExprWithCleanups(EmptyShell, unsigned NumObjects);
   ExprWithCleanups(Expr *SubExpr, bool CleanupsHaveSideEffects,
                    ArrayRef<CleanupObject> Objects);
@@ -3070,17 +3068,10 @@ public:
     return getObjects()[i];
   }
 
-  Expr *getSubExpr() { return cast<Expr>(SubExpr); }
-  const Expr *getSubExpr() const { return cast<Expr>(SubExpr); }
-
   bool cleanupsHaveSideEffects() const {
     return ExprWithCleanupsBits.CleanupsHaveSideEffects;
   }
 
-  /// As with any mutator of the AST, be very careful
-  /// when modifying an existing AST to preserve its invariants.
-  void setSubExpr(Expr *E) { SubExpr = E; }
-
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return SubExpr->getBeginLoc();
   }

include/clang/AST/RecursiveASTVisitor.h

@@ -2199,6 +2199,8 @@ DEF_TRAVERSE_STMT(ReturnStmt, {})
 DEF_TRAVERSE_STMT(SwitchStmt, {})
 DEF_TRAVERSE_STMT(WhileStmt, {})
 
+DEF_TRAVERSE_STMT(ConstantExpr, {})
+
 DEF_TRAVERSE_STMT(CXXDependentScopeMemberExpr, {
   TRY_TO(TraverseNestedNameSpecifierLoc(S->getQualifierLoc()));
   TRY_TO(TraverseDeclarationNameInfo(S->getMemberNameInfo()));

include/clang/Basic/StmtNodes.td

@@ -93,6 +93,10 @@ def VAArgExpr : DStmt<Expr>;
 def GenericSelectionExpr : DStmt<Expr>;
 def PseudoObjectExpr : DStmt<Expr>;
 
+// Wrapper expressions
+def FullExpr : DStmt<Expr, 1>;
+def ConstantExpr : DStmt<FullExpr>;
+
 // Atomic expressions
 def AtomicExpr : DStmt<Expr>;
 
@@ -131,7 +135,7 @@ def DependentScopeDeclRefExpr : DStmt<Expr>;
 def CXXConstructExpr : DStmt<Expr>;
 def CXXInheritedCtorInitExpr : DStmt<Expr>;
 def CXXBindTemporaryExpr : DStmt<Expr>;
-def ExprWithCleanups : DStmt<Expr>;
+def ExprWithCleanups : DStmt<FullExpr>;
 def CXXTemporaryObjectExpr : DStmt<CXXConstructExpr>;
 def CXXUnresolvedConstructExpr : DStmt<Expr>;
 def CXXDependentScopeMemberExpr : DStmt<Expr>;

include/clang/Serialization/ASTBitCodes.h

@@ -1618,6 +1618,9 @@ namespace serialization {
       /// A MS-style AsmStmt record.
       STMT_MSASM,
 
+      /// A constant expression context.
+      EXPR_CONSTANT,
+
       /// A PredefinedExpr record.
       EXPR_PREDEFINED,
 

lib/ARCMigrate/TransAutoreleasePool.cpp

@@ -403,8 +403,8 @@ private:
     return cast<Expr>(getEssential((Stmt*)E));
   }
   static Stmt *getEssential(Stmt *S) {
-    if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(S))
-      S = EWC->getSubExpr();
+    if (FullExpr *FE = dyn_cast<FullExpr>(S))
+      S = FE->getSubExpr();
     if (Expr *E = dyn_cast<Expr>(S))
       S = E->IgnoreParenCasts();
     return S;

lib/ARCMigrate/TransRetainReleaseDealloc.cpp

@@ -253,7 +253,7 @@ private:
     }
     while (OuterS && (isa<ParenExpr>(OuterS) ||
                       isa<CastExpr>(OuterS) ||
-                      isa<ExprWithCleanups>(OuterS)));
+                      isa<FullExpr>(OuterS)));
 
     if (!OuterS)
       return std::make_pair(prevStmt, nextStmt);
@@ -376,8 +376,8 @@ private:
 
     RecContainer = StmtE;
     Rec = Init->IgnoreParenImpCasts();
-    if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Rec))
-      Rec = EWC->getSubExpr()->IgnoreParenImpCasts();
+    if (FullExpr *FE = dyn_cast<FullExpr>(Rec))
+      Rec = FE->getSubExpr()->IgnoreParenImpCasts();
     RecRange = Rec->getSourceRange();
     if (SM.isMacroArgExpansion(RecRange.getBegin()))
       RecRange.setBegin(SM.getImmediateSpellingLoc(RecRange.getBegin()));

lib/ARCMigrate/TransUnbridgedCasts.cpp

@@ -372,7 +372,7 @@ private:
       Stmt *parent = E;
       do {
         parent = StmtMap->getParentIgnoreParenImpCasts(parent);
-      } while (parent && isa<ExprWithCleanups>(parent));
+      } while (parent && isa<FullExpr>(parent));
 
       if (ReturnStmt *retS = dyn_cast_or_null<ReturnStmt>(parent)) {
         std::string note = "remove the cast and change return type of function "

lib/ARCMigrate/Transforms.cpp

@@ -74,8 +74,8 @@ bool trans::isPlusOneAssign(const BinaryOperator *E) {
 bool trans::isPlusOne(const Expr *E) {
   if (!E)
     return false;
-  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(E))
-    E = EWC->getSubExpr();
+  if (const FullExpr *FE = dyn_cast<FullExpr>(E))
+    E = FE->getSubExpr();
 
   if (const ObjCMessageExpr *
         ME = dyn_cast<ObjCMessageExpr>(E->IgnoreParenCasts()))

lib/AST/Decl.cpp

@@ -2576,7 +2576,7 @@ Expr *ParmVarDecl::getDefaultArg() {
          "Default argument is not yet instantiated!");
 
   Expr *Arg = getInit();
-  if (auto *E = dyn_cast_or_null<ExprWithCleanups>(Arg))
+  if (auto *E = dyn_cast_or_null<FullExpr>(Arg))
     return E->getSubExpr();
 
   return Arg;

lib/AST/Expr.cpp

@@ -3126,6 +3126,11 @@ bool Expr::HasSideEffects(const ASTContext &Ctx,
     // These never have a side-effect.
     return false;
 
+  case ConstantExprClass:
+    // FIXME: Move this into the "return false;" block above.
+    return cast<ConstantExpr>(this)->getSubExpr()->HasSideEffects(
+        Ctx, IncludePossibleEffects);
+
   case CallExprClass:
   case CXXOperatorCallExprClass:
   case CXXMemberCallExprClass:

lib/AST/ExprCXX.cpp

@@ -1044,12 +1044,7 @@ bool LambdaExpr::isMutable() const {
 ExprWithCleanups::ExprWithCleanups(Expr *subexpr,
                                    bool CleanupsHaveSideEffects,
                                    ArrayRef<CleanupObject> objects)
-    : Expr(ExprWithCleanupsClass, subexpr->getType(),
-           subexpr->getValueKind(), subexpr->getObjectKind(),
-           subexpr->isTypeDependent(), subexpr->isValueDependent(),
-           subexpr->isInstantiationDependent(),
-           subexpr->containsUnexpandedParameterPack()),
-      SubExpr(subexpr) {
+    : FullExpr(ExprWithCleanupsClass, subexpr) {
   ExprWithCleanupsBits.CleanupsHaveSideEffects = CleanupsHaveSideEffects;
   ExprWithCleanupsBits.NumObjects = objects.size();
   for (unsigned i = 0, e = objects.size(); i != e; ++i)
@@ -1066,7 +1061,7 @@ ExprWithCleanups *ExprWithCleanups::Create(const ASTContext &C, Expr *subexpr,
 }
 
 ExprWithCleanups::ExprWithCleanups(EmptyShell empty, unsigned numObjects)
-    : Expr(ExprWithCleanupsClass, empty) {
+    : FullExpr(ExprWithCleanupsClass, empty) {
   ExprWithCleanupsBits.NumObjects = numObjects;
 }
 

lib/AST/ExprClassification.cpp

@@ -194,6 +194,9 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
   case Expr::DesignatedInitUpdateExprClass:
     return Cl::CL_PRValue;
 
+  case Expr::ConstantExprClass:
+    return ClassifyInternal(Ctx, cast<ConstantExpr>(E)->getSubExpr());
+
     // Next come the complicated cases.
   case Expr::SubstNonTypeTemplateParmExprClass:
     return ClassifyInternal(Ctx,

lib/AST/ExprConstant.cpp

@@ -143,8 +143,8 @@ namespace {
     // If we're doing a variable assignment from e.g. malloc(N), there will
     // probably be a cast of some kind. In exotic cases, we might also see a
     // top-level ExprWithCleanups. Ignore them either way.
-    if (const auto *EC = dyn_cast<ExprWithCleanups>(E))
-      E = EC->getSubExpr()->IgnoreParens();
+    if (const auto *FE = dyn_cast<FullExpr>(E))
+      E = FE->getSubExpr()->IgnoreParens();
 
     if (const auto *Cast = dyn_cast<CastExpr>(E))
       E = Cast->getSubExpr()->IgnoreParens();
@@ -11062,6 +11062,9 @@ static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
     return
       CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
 
+  case Expr::ConstantExprClass:
+    return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx);
+
   case Expr::ParenExprClass:
     return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
   case Expr::GenericSelectionExprClass:

lib/AST/ItaniumMangle.cpp

@@ -3507,6 +3507,10 @@ recurse:
   case Expr::CXXInheritedCtorInitExprClass:
     llvm_unreachable("unexpected statement kind");
 
+  case Expr::ConstantExprClass:
+    E = cast<ConstantExpr>(E)->getSubExpr();
+    goto recurse;
+
   // FIXME: invent manglings for all these.
   case Expr::BlockExprClass:
   case Expr::ChooseExprClass:

lib/AST/ParentMap.cpp

@@ -163,7 +163,7 @@ bool ParentMap::isConsumedExpr(Expr* E) const {
 
   // Ignore parents that don't guarantee consumption.
   while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P) ||
-               isa<ExprWithCleanups>(P))) {
+               isa<FullExpr>(P))) {
     DirectChild = P;
     P = getParent(P);
   }

lib/AST/Stmt.cpp

@@ -118,8 +118,8 @@ Stmt *Stmt::IgnoreImplicit() {
   while (s != lasts) {
     lasts = s;
 
-    if (auto *ewc = dyn_cast<ExprWithCleanups>(s))
-      s = ewc->getSubExpr();
+    if (auto *fe = dyn_cast<FullExpr>(s))
+      s = fe->getSubExpr();
 
     if (auto *mte = dyn_cast<MaterializeTemporaryExpr>(s))
       s = mte->GetTemporaryExpr();

lib/AST/StmtPrinter.cpp

@@ -906,6 +906,10 @@ void StmtPrinter::VisitOMPTargetTeamsDistributeSimdDirective(
 //  Expr printing methods.
 //===----------------------------------------------------------------------===//
 
+void StmtPrinter::VisitConstantExpr(ConstantExpr *Node) {
+  PrintExpr(Node->getSubExpr());
+}
+
 void StmtPrinter::VisitDeclRefExpr(DeclRefExpr *Node) {
   if (const auto *OCED = dyn_cast<OMPCapturedExprDecl>(Node->getDecl())) {
     OCED->getInit()->IgnoreImpCasts()->printPretty(OS, nullptr, Policy);

lib/AST/StmtProfile.cpp

@@ -996,6 +996,10 @@ void StmtProfiler::VisitExpr(const Expr *S) {
   VisitStmt(S);
 }
 
+void StmtProfiler::VisitConstantExpr(const ConstantExpr *S) {
+  VisitExpr(S);
+}
+
 void StmtProfiler::VisitDeclRefExpr(const DeclRefExpr *S) {
   VisitExpr(S);
   if (!Canonical)

lib/Analysis/LiveVariables.cpp

@@ -237,8 +237,8 @@ static const Stmt *LookThroughStmt(const Stmt *S) {
   while (S) {
     if (const Expr *Ex = dyn_cast<Expr>(S))
       S = Ex->IgnoreParens();
-    if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(S)) {
-      S = EWC->getSubExpr();
+    if (const FullExpr *FE = dyn_cast<FullExpr>(S)) {
+      S = FE->getSubExpr();
       continue;
     }
     if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(S)) {

lib/Analysis/ThreadSafety.cpp

@@ -1398,8 +1398,8 @@ const CallExpr* ThreadSafetyAnalyzer::getTrylockCallExpr(const Stmt *Cond,
     return getTrylockCallExpr(PE->getSubExpr(), C, Negate);
   else if (const auto *CE = dyn_cast<ImplicitCastExpr>(Cond))
     return getTrylockCallExpr(CE->getSubExpr(), C, Negate);
-  else if (const auto *EWC = dyn_cast<ExprWithCleanups>(Cond))
-    return getTrylockCallExpr(EWC->getSubExpr(), C, Negate);
+  else if (const auto *FE = dyn_cast<FullExpr>(Cond))
+    return getTrylockCallExpr(FE->getSubExpr(), C, Negate);
   else if (const auto *DRE = dyn_cast<DeclRefExpr>(Cond)) {
     const Expr *E = LocalVarMap.lookupExpr(DRE->getDecl(), C);
     return getTrylockCallExpr(E, C, Negate);

lib/Analysis/ThreadSafetyCommon.cpp

@@ -235,6 +235,8 @@ til::SExpr *SExprBuilder::translate(const Stmt *S, CallingContext *Ctx) {
              cast<BinaryConditionalOperator>(S), Ctx);
 
   // We treat these as no-ops
+  case Stmt::ConstantExprClass:
+    return translate(cast<ConstantExpr>(S)->getSubExpr(), Ctx);
   case Stmt::ParenExprClass:
     return translate(cast<ParenExpr>(S)->getSubExpr(), Ctx);
   case Stmt::ExprWithCleanupsClass:

lib/CodeGen/CGBlocks.cpp

@@ -859,10 +859,12 @@ static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) {
 /// Enter a full-expression with a non-trivial number of objects to
 /// clean up.  This is in this file because, at the moment, the only
 /// kind of cleanup object is a BlockDecl*.
-void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) {
-  assert(E->getNumObjects() != 0);
-  for (const ExprWithCleanups::CleanupObject &C : E->getObjects())
-    enterBlockScope(*this, C);
+void CodeGenFunction::enterNonTrivialFullExpression(const FullExpr *E) {
+  if (const auto EWC = dyn_cast<ExprWithCleanups>(E)) {
+    assert(EWC->getNumObjects() != 0);
+    for (const ExprWithCleanups::CleanupObject &C : EWC->getObjects())
+      enterBlockScope(*this, C);
+  }
 }
 
 /// Find the layout for the given block in a linked list and remove it.

lib/CodeGen/CGDecl.cpp

@@ -754,9 +754,9 @@ void CodeGenFunction::EmitScalarInit(const Expr *init, const ValueDecl *D,
 
   // If we're emitting a value with lifetime, we have to do the
   // initialization *before* we leave the cleanup scopes.
-  if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) {
-    enterFullExpression(ewc);
-    init = ewc->getSubExpr();
+  if (const FullExpr *fe = dyn_cast<FullExpr>(init)) {
+    enterFullExpression(fe);
+    init = fe->getSubExpr();
   }
   CodeGenFunction::RunCleanupsScope Scope(*this);
 

lib/CodeGen/CGStmt.cpp

@@ -1047,10 +1047,9 @@ void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
   // exception to our over-conservative rules about not jumping to
   // statements following block literals with non-trivial cleanups.
   RunCleanupsScope cleanupScope(*this);
-  if (const ExprWithCleanups *cleanups =
-        dyn_cast_or_null<ExprWithCleanups>(RV)) {
-    enterFullExpression(cleanups);
-    RV = cleanups->getSubExpr();
+  if (const FullExpr *fe = dyn_cast_or_null<FullExpr>(RV)) {
+    enterFullExpression(fe);
+    RV = fe->getSubExpr();
   }
 
   // FIXME: Clean this up by using an LValue for ReturnTemp,

lib/CodeGen/CGStmtOpenMP.cpp

@@ -3986,13 +3986,13 @@ void CodeGenFunction::EmitOMPAtomicDirective(const OMPAtomicDirective &S) {
   }
 
   const Stmt *CS = S.getInnermostCapturedStmt()->IgnoreContainers();
-  if (const auto *EWC = dyn_cast<ExprWithCleanups>(CS))
-    enterFullExpression(EWC);
+  if (const auto *FE = dyn_cast<FullExpr>(CS))
+    enterFullExpression(FE);
   // Processing for statements under 'atomic capture'.
   if (const auto *Compound = dyn_cast<CompoundStmt>(CS)) {
     for (const Stmt *C : Compound->body()) {
-      if (const auto *EWC = dyn_cast<ExprWithCleanups>(C))
-        enterFullExpression(EWC);
+      if (const auto *FE = dyn_cast<FullExpr>(C))
+        enterFullExpression(FE);
     }
   }
 

lib/CodeGen/CodeGenFunction.h

@@ -3947,11 +3947,13 @@ public:
 
   void EmitSynthesizedCXXCopyCtor(Address Dest, Address Src, const Expr *Exp);
 
-  void enterFullExpression(const ExprWithCleanups *E) {
-    if (E->getNumObjects() == 0) return;
+  void enterFullExpression(const FullExpr *E) {
+    if (const auto *EWC = dyn_cast<ExprWithCleanups>(E))
+      if (EWC->getNumObjects() == 0)
+        return;
     enterNonTrivialFullExpression(E);
   }
-  void enterNonTrivialFullExpression(const ExprWithCleanups *E);
+  void enterNonTrivialFullExpression(const FullExpr *E);
 
   void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint = true);
 

lib/Sema/SemaExceptionSpec.cpp

@@ -1051,6 +1051,9 @@ CanThrowResult Sema::canThrow(const Expr *E) {
   //   [Can throw] if in a potentially-evaluated context the expression would
   //   contain:
   switch (E->getStmtClass()) {
+  case Expr::ConstantExprClass:
+    return canThrow(cast<ConstantExpr>(E)->getSubExpr());
+
   case Expr::CXXThrowExprClass:
     //   - a potentially evaluated throw-expression
     return CT_Can;

lib/Sema/SemaInit.cpp

@@ -6510,8 +6510,8 @@ static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
   do {
     Old = Init;
 
-    if (auto *EWC = dyn_cast<ExprWithCleanups>(Init))
-      Init = EWC->getSubExpr();
+    if (auto *FE = dyn_cast<FullExpr>(Init))
+      Init = FE->getSubExpr();
 
     if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
       // If this is just redundant braces around an initializer, step over it.
@@ -6634,8 +6634,8 @@ static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
       Init = DIE->getExpr();
     }
 
-    if (auto *EWC = dyn_cast<ExprWithCleanups>(Init))
-      Init = EWC->getSubExpr();
+    if (auto *FE = dyn_cast<FullExpr>(Init))
+      Init = FE->getSubExpr();
 
     // Dig out the expression which constructs the extended temporary.
     Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());

lib/Sema/SemaOpenMP.cpp

@@ -669,8 +669,8 @@ bool isParallelOrTaskRegion(OpenMPDirectiveKind DKind) {
 } // namespace
 
 static const Expr *getExprAsWritten(const Expr *E) {
-  if (const auto *ExprTemp = dyn_cast<ExprWithCleanups>(E))
-    E = ExprTemp->getSubExpr();
+  if (const auto *FE = dyn_cast<FullExpr>(E))
+    E = FE->getSubExpr();
 
   if (const auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
     E = MTE->GetTemporaryExpr();

lib/Sema/SemaStmt.cpp

@@ -246,7 +246,7 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
   // we might want to make a more specific diagnostic.  Check for one of these
   // cases now.
   unsigned DiagID = diag::warn_unused_expr;
-  if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E))
+  if (const FullExpr *Temps = dyn_cast<FullExpr>(E))
     E = Temps->getSubExpr();
   if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
     E = TempExpr->getSubExpr();
@@ -631,8 +631,8 @@ static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
 /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
 /// potentially integral-promoted expression @p expr.
 static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
-  if (const auto *CleanUps = dyn_cast<ExprWithCleanups>(E))
-    E = CleanUps->getSubExpr();
+  if (const auto *FE = dyn_cast<FullExpr>(E))
+    E = FE->getSubExpr();
   while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
     if (ImpCast->getCastKind() != CK_IntegralCast) break;
     E = ImpCast->getSubExpr();

lib/Sema/TreeTransform.h

@@ -3344,8 +3344,8 @@ ExprResult TreeTransform<Derived>::TransformInitializer(Expr *Init,
   if (!Init)
     return Init;
 
-  if (ExprWithCleanups *ExprTemp = dyn_cast<ExprWithCleanups>(Init))
-    Init = ExprTemp->getSubExpr();
+  if (auto *FE = dyn_cast<FullExpr>(Init))
+    Init = FE->getSubExpr();
 
   if (auto *AIL = dyn_cast<ArrayInitLoopExpr>(Init))
     Init = AIL->getCommonExpr();
@@ -8914,6 +8914,12 @@ TreeTransform<Derived>::TransformOMPIsDevicePtrClause(OMPIsDevicePtrClause *C) {
 //===----------------------------------------------------------------------===//
 // Expression transformation
 //===----------------------------------------------------------------------===//
+template<typename Derived>
+ExprResult
+TreeTransform<Derived>::TransformConstantExpr(ConstantExpr *E) {
+  return TransformExpr(E->getSubExpr());
+}
+
 template<typename Derived>
 ExprResult
 TreeTransform<Derived>::TransformPredefinedExpr(PredefinedExpr *E) {

lib/Serialization/ASTReaderStmt.cpp

@@ -524,6 +524,11 @@ void ASTStmtReader::VisitExpr(Expr *E) {
          "Incorrect expression field count");
 }
 
+void ASTStmtReader::VisitConstantExpr(ConstantExpr *E) {
+  VisitExpr(E);
+  E->setSubExpr(Record.readSubExpr());
+}
+
 void ASTStmtReader::VisitPredefinedExpr(PredefinedExpr *E) {
   VisitExpr(E);
   bool HasFunctionName = Record.readInt();
@@ -2385,6 +2390,10 @@ Stmt *ASTReader::ReadStmtFromStream(ModuleFile &F) {
           Context, Record[ASTStmtReader::NumStmtFields]);
       break;
 
+    case EXPR_CONSTANT:
+      S = new (Context) ConstantExpr(Empty);
+      break;
+
     case EXPR_PREDEFINED:
       S = PredefinedExpr::CreateEmpty(
           Context,

lib/Serialization/ASTWriterStmt.cpp

@@ -426,6 +426,12 @@ void ASTStmtWriter::VisitExpr(Expr *E) {
   Record.push_back(E->getObjectKind());
 }
 
+void ASTStmtWriter::VisitConstantExpr(ConstantExpr *E) {
+  VisitExpr(E);
+  Record.AddStmt(E->getSubExpr());
+  Code = serialization::EXPR_CONSTANT;
+}
+
 void ASTStmtWriter::VisitPredefinedExpr(PredefinedExpr *E) {
   VisitExpr(E);
 

lib/StaticAnalyzer/Checkers/DeadStoresChecker.cpp

@@ -329,9 +329,8 @@ public:
             return;
 
           if (const Expr *E = V->getInit()) {
-            while (const ExprWithCleanups *exprClean =
-                    dyn_cast<ExprWithCleanups>(E))
-              E = exprClean->getSubExpr();
+            while (const FullExpr *FE = dyn_cast<FullExpr>(E))
+              E = FE->getSubExpr();
 
             // Look through transitive assignments, e.g.:
             // int x = y = 0;

lib/StaticAnalyzer/Core/BugReporter.cpp

@@ -1265,7 +1265,7 @@ static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) {
     if (!S)
       break;
 
-    if (isa<ExprWithCleanups>(S) ||
+    if (isa<FullExpr>(S) ||
         isa<CXXBindTemporaryExpr>(S) ||
         isa<SubstNonTypeTemplateParmExpr>(S))
       continue;

lib/StaticAnalyzer/Core/BugReporterVisitors.cpp

@@ -136,8 +136,8 @@ const Expr *bugreporter::getDerefExpr(const Stmt *S) {
       E = AE->getBase();
     } else if (const auto *PE = dyn_cast<ParenExpr>(E)) {
       E = PE->getSubExpr();
-    } else if (const auto *EWC = dyn_cast<ExprWithCleanups>(E)) {
-      E = EWC->getSubExpr();
+    } else if (const auto *FE = dyn_cast<FullExpr>(E)) {
+      E = FE->getSubExpr();
     } else {
       // Other arbitrary stuff.
       break;
@@ -1494,8 +1494,8 @@ static const MemRegion *getLocationRegionIfReference(const Expr *E,
 static const Expr *peelOffOuterExpr(const Expr *Ex,
                                     const ExplodedNode *N) {
   Ex = Ex->IgnoreParenCasts();
-  if (const auto *EWC = dyn_cast<ExprWithCleanups>(Ex))
-    return peelOffOuterExpr(EWC->getSubExpr(), N);
+  if (const auto *FE = dyn_cast<FullExpr>(Ex))
+    return peelOffOuterExpr(FE->getSubExpr(), N);
   if (const auto *OVE = dyn_cast<OpaqueValueExpr>(Ex))
     return peelOffOuterExpr(OVE->getSourceExpr(), N);
   if (const auto *POE = dyn_cast<PseudoObjectExpr>(Ex)) {

lib/StaticAnalyzer/Core/Environment.cpp

@@ -44,6 +44,9 @@ static const Expr *ignoreTransparentExprs(const Expr *E) {
   case Stmt::ExprWithCleanupsClass:
     E = cast<ExprWithCleanups>(E)->getSubExpr();
     break;
+  case Stmt::ConstantExprClass:
+    E = cast<ConstantExpr>(E)->getSubExpr();
+    break;
   case Stmt::CXXBindTemporaryExprClass:
     E = cast<CXXBindTemporaryExpr>(E)->getSubExpr();
     break;

lib/StaticAnalyzer/Core/ExprEngine.cpp

@@ -1267,6 +1267,9 @@ void ExprEngine::Visit(const Stmt *S, ExplodedNode *Pred,
     case Stmt::ObjCPropertyRefExprClass:
       llvm_unreachable("These are handled by PseudoObjectExpr");
 
+    case Expr::ConstantExprClass:
+      return Visit(cast<ConstantExpr>(S)->getSubExpr(), Pred, DstTop);
+
     case Stmt::GNUNullExprClass: {
       // GNU __null is a pointer-width integer, not an actual pointer.
       ProgramStateRef state = Pred->getState();

tools/libclang/CXCursor.cpp

@@ -343,6 +343,10 @@ CXCursor cxcursor::MakeCXCursor(const Stmt *S, const Decl *Parent,
     K = CXCursor_CharacterLiteral;
     break;
 
+  case Stmt::ConstantExprClass:
+    return MakeCXCursor(cast<ConstantExpr>(S)->getSubExpr(),
+                        Parent, TU, RegionOfInterest);
+
   case Stmt::ParenExprClass:
     K = CXCursor_ParenExpr;
     break;