Added an assertion to constant evaluation enty points that prohibits …

…dependent expressions

Summary:
Constant evaluator does not work on value-dependent or type-dependent
expressions.

Also fixed bugs uncovered by these assertions.

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61522

llvm-svn: 361050

clang/lib/AST/Expr.cpp

@@ -2974,6 +2974,9 @@ bool Expr::hasAnyTypeDependentArguments(ArrayRef<Expr *> Exprs) {
 
 bool Expr::isConstantInitializer(ASTContext &Ctx, bool IsForRef,
                                  const Expr **Culprit) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   // This function is attempting whether an expression is an initializer
   // which can be evaluated at compile-time. It very closely parallels
   // ConstExprEmitter in CGExprConstant.cpp; if they don't match, it

clang/lib/AST/ExprConstant.cpp

@@ -11642,32 +11642,43 @@ static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
 /// will be applied to the result.
 bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
                             bool InConstantContext) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
   EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
   Info.InConstantContext = InConstantContext;
   return ::EvaluateAsRValue(this, Result, Ctx, Info);
 }
 
 bool Expr::EvaluateAsBooleanCondition(bool &Result,
                                       const ASTContext &Ctx) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
   EvalResult Scratch;
   return EvaluateAsRValue(Scratch, Ctx) &&
          HandleConversionToBool(Scratch.Val, Result);
 }
 
 bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
                          SideEffectsKind AllowSideEffects) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
   EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
   return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info);
 }
 
 bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
                                 SideEffectsKind AllowSideEffects) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
   EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
   return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info);
 }
 
 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
                            SideEffectsKind AllowSideEffects) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   if (!getType()->isRealFloatingType())
     return false;
 
@@ -11681,6 +11692,9 @@ bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
 }
 
 bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
 
   LValue LV;
@@ -11696,6 +11710,9 @@ bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
 
 bool Expr::EvaluateAsConstantExpr(EvalResult &Result, ConstExprUsage Usage,
                                   const ASTContext &Ctx) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
   EvalInfo Info(Ctx, Result, EM);
   Info.InConstantContext = true;
@@ -11710,6 +11727,9 @@ bool Expr::EvaluateAsConstantExpr(EvalResult &Result, ConstExprUsage Usage,
 bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
                                  const VarDecl *VD,
                             SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   // FIXME: Evaluating initializers for large array and record types can cause
   // performance problems. Only do so in C++11 for now.
   if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
@@ -11752,13 +11772,19 @@ bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
 /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
 /// constant folded, but discard the result.
 bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   EvalResult Result;
   return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) &&
          !hasUnacceptableSideEffect(Result, SEK);
 }
 
 APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
                     SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   EvalResult EVResult;
   EVResult.Diag = Diag;
   EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
@@ -11774,6 +11800,9 @@ APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
 
 APSInt Expr::EvaluateKnownConstIntCheckOverflow(
     const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   EvalResult EVResult;
   EVResult.Diag = Diag;
   EvalInfo Info(Ctx, EVResult, EvalInfo::EM_EvaluateForOverflow);
@@ -11788,6 +11817,9 @@ APSInt Expr::EvaluateKnownConstIntCheckOverflow(
 }
 
 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   bool IsConst;
   EvalResult EVResult;
   if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) {
@@ -12269,6 +12301,9 @@ static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
 
 bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
                                  SourceLocation *Loc) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   if (Ctx.getLangOpts().CPlusPlus11)
     return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
 
@@ -12282,6 +12317,9 @@ bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
 
 bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx,
                                  SourceLocation *Loc, bool isEvaluated) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   if (Ctx.getLangOpts().CPlusPlus11)
     return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc);
 
@@ -12305,11 +12343,17 @@ bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, const ASTContext &Ctx,
 }
 
 bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   return CheckICE(this, Ctx).Kind == IK_ICE;
 }
 
 bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
                                SourceLocation *Loc) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   // We support this checking in C++98 mode in order to diagnose compatibility
   // issues.
   assert(Ctx.getLangOpts().CPlusPlus);
@@ -12338,6 +12382,9 @@ bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
                                     const FunctionDecl *Callee,
                                     ArrayRef<const Expr*> Args,
                                     const Expr *This) const {
+  assert(!isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   Expr::EvalStatus Status;
   EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
   Info.InConstantContext = true;
@@ -12419,6 +12466,9 @@ bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
                                               const FunctionDecl *FD,
                                               SmallVectorImpl<
                                                 PartialDiagnosticAt> &Diags) {
+  assert(!E->isValueDependent() &&
+         "Expression evaluator can't be called on a dependent expression.");
+
   Expr::EvalStatus Status;
   Status.Diag = &Diags;
 

clang/lib/Sema/SemaOpenMP.cpp

@@ -5894,14 +5894,21 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   if (CollapseLoopCountExpr) {
     // Found 'collapse' clause - calculate collapse number.
     Expr::EvalResult Result;
-    if (CollapseLoopCountExpr->EvaluateAsInt(Result, SemaRef.getASTContext()))
+    if (!CollapseLoopCountExpr->isValueDependent() &&
+        CollapseLoopCountExpr->EvaluateAsInt(Result, SemaRef.getASTContext())) {
       NestedLoopCount = Result.Val.getInt().getLimitedValue();
+    } else {
+      Built.clear(/*size=*/1);
+      return 1;
+    }
   }
   unsigned OrderedLoopCount = 1;
   if (OrderedLoopCountExpr) {
     // Found 'ordered' clause - calculate collapse number.
     Expr::EvalResult EVResult;
-    if (OrderedLoopCountExpr->EvaluateAsInt(EVResult, SemaRef.getASTContext())) {
+    if (!OrderedLoopCountExpr->isValueDependent() &&
+        OrderedLoopCountExpr->EvaluateAsInt(EVResult,
+                                            SemaRef.getASTContext())) {
       llvm::APSInt Result = EVResult.Val.getInt();
       if (Result.getLimitedValue() < NestedLoopCount) {
         SemaRef.Diag(OrderedLoopCountExpr->getExprLoc(),
@@ -5912,6 +5919,9 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
             << CollapseLoopCountExpr->getSourceRange();
       }
       OrderedLoopCount = Result.getLimitedValue();
+    } else {
+      Built.clear(/*size=*/1);
+      return 1;
     }
   }
   // This is helper routine for loop directives (e.g., 'for', 'simd',

clang/lib/Sema/SemaOverload.cpp

@@ -6376,7 +6376,8 @@ EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function, ArrayRef<Expr *> Args,
     APValue Result;
     // FIXME: This doesn't consider value-dependent cases, because doing so is
     // very difficult. Ideally, we should handle them more gracefully.
-    if (!EIA->getCond()->EvaluateWithSubstitution(
+    if (EIA->getCond()->isValueDependent() ||
+        !EIA->getCond()->EvaluateWithSubstitution(
             Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)))
       return EIA;
 
@@ -9562,7 +9563,8 @@ static bool isFunctionAlwaysEnabled(const ASTContext &Ctx,
                                     const FunctionDecl *FD) {
   for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) {
     bool AlwaysTrue;
-    if (!EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
+    if (EnableIf->getCond()->isValueDependent() ||
+        !EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
       return false;
     if (!AlwaysTrue)
       return false;