add ConstEvaluatedExprVisitor

[scott-0]

Summary

Adds a version of EvaluatedExprVisitor for visiting const Stmt*s and uses it in a few places thereby removing some casting away of const. Changes EvaluatedExprVisitor to hold it's ASTContext& as const and adds a few 'const's that this allows. Removes an spurious #include.

Overall, no functional change. I'm also going to use ConstEvaluatedExprVisitor in a subsequent patch about side-effect of StmtExprs.

[rs]

LGTM, but someone else should approve as well

[rsmith]

LGTM

llvm/tools/clang/include/clang/AST/EvaluatedExprVisitor.h

34 ↗

(On Diff #27029)

No blank line here.

114 ↗

(On Diff #27029)

Likewise.

124 ↗

(On Diff #27029)

Likewise.

cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h

 #include "clang/AST/StmtVisitor.h"
 
 namespace clang {
   
 class ASTContext;
   
 /// \brief Given a potentially-evaluated expression, this visitor visits all
 /// of its potentially-evaluated subexpressions, recursively.
-template<typename ImplClass>
-class EvaluatedExprVisitor : public StmtVisitor<ImplClass> {
-  ASTContext &Context;
-  
+template<template <typename> class Ptr, typename ImplClass>
+class EvaluatedExprVisitorBase : public StmtVisitorBase<Ptr, ImplClass, void> {
+  const ASTContext &Context;
 public:
-  explicit EvaluatedExprVisitor(ASTContext &Context) : Context(Context) { }
-  
+#define PTR(CLASS) typename Ptr<CLASS>::type
+
+  explicit EvaluatedExprVisitorBase(const ASTContext &Context) : Context(Context) { }
   // Expressions that have no potentially-evaluated subexpressions (but may have
   // other sub-expressions).
-  void VisitDeclRefExpr(DeclRefExpr *E) { }
-  void VisitOffsetOfExpr(OffsetOfExpr *E) { }
-  void VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E) { }
-  void VisitExpressionTraitExpr(ExpressionTraitExpr *E) { }
-  void VisitBlockExpr(BlockExpr *E) { }
-  void VisitCXXUuidofExpr(CXXUuidofExpr *E) { }  
-  void VisitCXXNoexceptExpr(CXXNoexceptExpr *E) { }
-  
-  void VisitMemberExpr(MemberExpr *E) {
+  void VisitDeclRefExpr(PTR(DeclRefExpr) E) { }
+  void VisitOffsetOfExpr(PTR(OffsetOfExpr) E) { }
+  void VisitUnaryExprOrTypeTraitExpr(PTR(UnaryExprOrTypeTraitExpr) E) { }
+  void VisitExpressionTraitExpr(PTR(ExpressionTraitExpr) E) { }
+  void VisitBlockExpr(PTR(BlockExpr) E) { }
+  void VisitCXXUuidofExpr(PTR(CXXUuidofExpr) E) { }
+  void VisitCXXNoexceptExpr(PTR(CXXNoexceptExpr) E) { }
+  void VisitMemberExpr(PTR(MemberExpr) E) {
     // Only the base matters.
     return this->Visit(E->getBase());
   }
-  
-  void VisitChooseExpr(ChooseExpr *E) {
+  void VisitChooseExpr(PTR(ChooseExpr) E) {
     // Don't visit either child expression if the condition is dependent.
     if (E->getCond()->isValueDependent())
       return;
     // Only the selected subexpression matters; the other one is not evaluated.
     return this->Visit(E->getChosenSubExpr());
   }
 
-  void VisitGenericSelectionExpr(GenericSelectionExpr *E) {
+  void VisitGenericSelectionExpr(PTR(GenericSelectionExpr) E) {
     // The controlling expression of a generic selection is not evaluated.
 
     // Don't visit either child expression if the condition is type-dependent.
     if (E->isResultDependent())
       return;
     // Only the selected subexpression matters; the other subexpressions and the
     // controlling expression are not evaluated.
     return this->Visit(E->getResultExpr());
   }
 
-  void VisitDesignatedInitExpr(DesignatedInitExpr *E) {
+  void VisitDesignatedInitExpr(PTR(DesignatedInitExpr) E) {
     // Only the actual initializer matters; the designators are all constant
     // expressions.
     return this->Visit(E->getInit());
   }
 
-  void VisitCXXTypeidExpr(CXXTypeidExpr *E) {
+  void VisitCXXTypeidExpr(PTR(CXXTypeidExpr) E) {
     if (E->isPotentiallyEvaluated())
       return this->Visit(E->getExprOperand());
   }
 
-  void VisitCallExpr(CallExpr *CE) {
+  void VisitCallExpr(PTR(CallExpr) CE) {
     if (!CE->isUnevaluatedBuiltinCall(Context))
       return static_cast<ImplClass*>(this)->VisitExpr(CE);
   }
 
-  void VisitLambdaExpr(LambdaExpr *LE) {
+  void VisitLambdaExpr(PTR(LambdaExpr) LE) {
     // Only visit the capture initializers, and not the body.
     for (LambdaExpr::capture_init_iterator I = LE->capture_init_begin(),
                                            E = LE->capture_init_end();
          I != E; ++I)
       if (*I)
         this->Visit(*I);
   }
 
   /// \brief The basis case walks all of the children of the statement or
   /// expression, assuming they are all potentially evaluated.
-  void VisitStmt(Stmt *S) {
-    for (Stmt::child_range C = S->children(); C; ++C)
+  void VisitStmt(PTR(Stmt) S) {
+    for (auto C = S->children(); C; ++C)
       if (*C)
         this->Visit(*C);
   }
+
+#undef PTR
+};
+
+/// EvaluatedExprVisitor - This class visits 'Expr *'s
+template<typename ImplClass>
+class EvaluatedExprVisitor
+ : public EvaluatedExprVisitorBase<make_ptr, ImplClass> {
+public:
+  explicit EvaluatedExprVisitor(const ASTContext &Context) :
+    EvaluatedExprVisitorBase<make_ptr, ImplClass>(Context) { }
+};
+
+/// ConstEvaluatedExprVisitor - This class visits 'const Expr *'s.
+template<typename ImplClass>
+class ConstEvaluatedExprVisitor
+ : public EvaluatedExprVisitorBase<make_const_ptr, ImplClass> {
+public:
+  explicit ConstEvaluatedExprVisitor(const ASTContext &Context) :
+    EvaluatedExprVisitorBase<make_const_ptr, ImplClass>(Context) { }
 };
 
 }
 
 #endif // LLVM_CLANG_AST_EVALUATEDEXPRVISITOR_H

cfe/trunk/include/clang/AST/Expr.h

public:
   /// potential side effects (such as function call-like expressions,
   /// instantiation-dependent expressions, or invocations from a macro) as not
   /// having side effects.
   bool HasSideEffects(const ASTContext &Ctx,
                       bool IncludePossibleEffects = true) const;
 
   /// \brief Determine whether this expression involves a call to any function
   /// that is not trivial.
-  bool hasNonTrivialCall(ASTContext &Ctx);
+  bool hasNonTrivialCall(const ASTContext &Ctx) const;
 
   /// EvaluateKnownConstInt - Call EvaluateAsRValue and return the folded
   /// integer. This must be called on an expression that constant folds to an
   /// integer.
   llvm::APSInt EvaluateKnownConstInt(const ASTContext &Ctx,
                     SmallVectorImpl<PartialDiagnosticAt> *Diag = nullptr) const;
 
   void EvaluateForOverflow(const ASTContext &Ctx) const;
public:
   unsigned getNumCommas() const { return NumArgs ? NumArgs - 1 : 0; }
 
   /// getBuiltinCallee - If this is a call to a builtin, return the builtin ID
   /// of the callee. If not, return 0.
   unsigned getBuiltinCallee() const;
 
   /// \brief Returns \c true if this is a call to a builtin which does not
   /// evaluate side-effects within its arguments.
-  bool isUnevaluatedBuiltinCall(ASTContext &Ctx) const;
+  bool isUnevaluatedBuiltinCall(const ASTContext &Ctx) const;
 
   /// getCallReturnType - Get the return type of the call expr. This is not
   /// always the type of the expr itself, if the return type is a reference
   /// type.
   QualType getCallReturnType(const ASTContext &Ctx) const;
 
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }

cfe/trunk/lib/AST/Expr.cpp

if (!FDecl)
     return 0;
 
   if (!FDecl->getIdentifier())
     return 0;
 
   return FDecl->getBuiltinID();
 }
 
-bool CallExpr::isUnevaluatedBuiltinCall(ASTContext &Ctx) const {
+bool CallExpr::isUnevaluatedBuiltinCall(const ASTContext &Ctx) const {
   if (unsigned BI = getBuiltinCallee())
     return Ctx.BuiltinInfo.isUnevaluated(BI);
   return false;
 }
 
 QualType CallExpr::getCallReturnType(const ASTContext &Ctx) const {
   const Expr *Callee = getCallee();
   QualType CalleeType = Callee->getType();
if (const Stmt *S = *SubStmts)
       if (cast<Expr>(S)->HasSideEffects(Ctx, IncludePossibleEffects))
         return true;
 
   return false;
 }
 
 namespace {
   /// \brief Look for a call to a non-trivial function within an expression.
-  class NonTrivialCallFinder : public EvaluatedExprVisitor<NonTrivialCallFinder>
+  class NonTrivialCallFinder : public ConstEvaluatedExprVisitor<NonTrivialCallFinder>
   {
-    typedef EvaluatedExprVisitor<NonTrivialCallFinder> Inherited;
-    
+    typedef ConstEvaluatedExprVisitor<NonTrivialCallFinder> Inherited;
     bool NonTrivial;
     
   public:
-    explicit NonTrivialCallFinder(ASTContext &Context) 
+    explicit NonTrivialCallFinder(const ASTContext &Context)
       : Inherited(Context), NonTrivial(false) { }
     
     bool hasNonTrivialCall() const { return NonTrivial; }
-    
-    void VisitCallExpr(CallExpr *E) {
-      if (CXXMethodDecl *Method
-          = dyn_cast_or_null<CXXMethodDecl>(E->getCalleeDecl())) {
+    void VisitCallExpr(const CallExpr *E) {
+      if (const CXXMethodDecl *Method
+          = dyn_cast_or_null<const CXXMethodDecl>(E->getCalleeDecl())) {
         if (Method->isTrivial()) {
           // Recurse to children of the call.
           Inherited::VisitStmt(E);
           return;
         }
       }
       
       NonTrivial = true;
     }
-    
-    void VisitCXXConstructExpr(CXXConstructExpr *E) {
+    void VisitCXXConstructExpr(const CXXConstructExpr *E) {
       if (E->getConstructor()->isTrivial()) {
         // Recurse to children of the call.
         Inherited::VisitStmt(E);
         return;
       }
       
       NonTrivial = true;
     }
-    
-    void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
+    void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
       if (E->getTemporary()->getDestructor()->isTrivial()) {
         Inherited::VisitStmt(E);
         return;
       }
       
       NonTrivial = true;
     }
   };
 }
 
-bool Expr::hasNonTrivialCall(ASTContext &Ctx) {
+bool Expr::hasNonTrivialCall(const ASTContext &Ctx) const {
   NonTrivialCallFinder Finder(Ctx);
   Finder.Visit(this);
   return Finder.hasNonTrivialCall();  
 }
 
 /// isNullPointerConstant - C99 6.3.2.3p3 - Return whether this is a null 
 /// pointer constant or not, as well as the specific kind of constant detected.
 /// Null pointer constants can be integer constant expressions with the

cfe/trunk/lib/CodeGen/CGClass.cpp

void Emit(CodeGenFunction &CGF, Flags flags) override {
                                                   BaseIsVirtual);
       CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual,
                                 /*Delegating=*/false, Addr);
     }
   };
 
   /// A visitor which checks whether an initializer uses 'this' in a
   /// way which requires the vtable to be properly set.
-  struct DynamicThisUseChecker : EvaluatedExprVisitor<DynamicThisUseChecker> {
-    typedef EvaluatedExprVisitor<DynamicThisUseChecker> super;
+  struct DynamicThisUseChecker : ConstEvaluatedExprVisitor<DynamicThisUseChecker> {
+    typedef ConstEvaluatedExprVisitor<DynamicThisUseChecker> super;
 
     bool UsesThis;
 
-    DynamicThisUseChecker(ASTContext &C) : super(C), UsesThis(false) {}
+    DynamicThisUseChecker(const ASTContext &C) : super(C), UsesThis(false) {}
 
     // Black-list all explicit and implicit references to 'this'.
     //
     // Do we need to worry about external references to 'this' derived
     // from arbitrary code?  If so, then anything which runs arbitrary
     // external code might potentially access the vtable.
-    void VisitCXXThisExpr(CXXThisExpr *E) { UsesThis = true; }
+    void VisitCXXThisExpr(const CXXThisExpr *E) { UsesThis = true; }
   };
 }
 
 static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
   DynamicThisUseChecker Checker(C);
-  Checker.Visit(const_cast<Expr*>(Init));
+  Checker.Visit(Init);
   return Checker.UsesThis;
 }
 
 static void EmitBaseInitializer(CodeGenFunction &CGF,
                                 const CXXRecordDecl *ClassDecl,
                                 CXXCtorInitializer *BaseInit,
                                 CXXCtorType CtorType) {
   assert(BaseInit->isBaseInitializer() &&

cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp

 //===----------------------------------------------------------------------===//
 // -Wuninitialized
 //===----------------------------------------------------------------------===//
 
 namespace {
 /// ContainsReference - A visitor class to search for references to
 /// a particular declaration (the needle) within any evaluated component of an
 /// expression (recursively).
-class ContainsReference : public EvaluatedExprVisitor<ContainsReference> {
+class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
   bool FoundReference;
   const DeclRefExpr *Needle;
 
 public:
+  typedef ConstEvaluatedExprVisitor<ContainsReference> Inherited;
+
   ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
-    : EvaluatedExprVisitor<ContainsReference>(Context),
-      FoundReference(false), Needle(Needle) {}
+    : Inherited(Context), FoundReference(false), Needle(Needle) {}
 
-  void VisitExpr(Expr *E) {
+  void VisitExpr(const Expr *E) {
     // Stop evaluating if we already have a reference.
     if (FoundReference)
       return;
 
-    EvaluatedExprVisitor<ContainsReference>::VisitExpr(E);
+    Inherited::VisitExpr(E);
   }
 
-  void VisitDeclRefExpr(DeclRefExpr *E) {
+  void VisitDeclRefExpr(const DeclRefExpr *E) {
     if (E == Needle)
       FoundReference = true;
     else
-      EvaluatedExprVisitor<ContainsReference>::VisitDeclRefExpr(E);
+      Inherited::VisitDeclRefExpr(E);
   }
 
   bool doesContainReference() const { return FoundReference; }
 };
 }
 
 static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
   QualType VariableTy = VD->getType().getCanonicalType();
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
     // This is used to indicate to GCC that 'x' is intentionally left
     // uninitialized. Proven code paths which access 'x' in
     // an uninitialized state after this will still warn.
     if (const Expr *Initializer = VD->getInit()) {
       if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
         return false;
 
       ContainsReference CR(S.Context, DRE);
-      CR.Visit(const_cast<Expr*>(Initializer));
+      CR.Visit(Initializer);
       if (CR.doesContainReference()) {
         S.Diag(DRE->getLocStart(),
                diag::warn_uninit_self_reference_in_init)
           << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
         return true;
       }
     }
 

cfe/trunk/lib/Sema/SemaExprCXX.cpp

 #include "clang/Sema/SemaInternal.h"
 #include "TreeTransform.h"
 #include "TypeLocBuilder.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTLambda.h"
 #include "clang/AST/CXXInheritance.h"
 #include "clang/AST/CharUnits.h"
 #include "clang/AST/DeclObjC.h"
-#include "clang/AST/EvaluatedExprVisitor.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/DeclSpec.h"