Bug 497875 - Avoid evaluating isConstantExpression multiple times

Change-Id: I54d6b533f5b21294a92319ea1d45d4f18962a460

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalBinary.java

@@ -81,6 +81,8 @@ public class EvalBinary extends CPPDependentEvaluation {
 
 	private ICPPFunction fOverload= CPPFunction.UNINITIALIZED_FUNCTION;
 	private IType fType;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalBinary(int operator, ICPPEvaluation arg1, ICPPEvaluation arg2, IASTNode pointOfDefinition) {
 		this(operator, arg1, arg2, findEnclosingTemplate(pointOfDefinition));
@@ -201,9 +203,17 @@ public class EvalBinary extends CPPDependentEvaluation {
 	public boolean isValueDependent() {
 		return fArg1.isValueDependent() || fArg2.isValueDependent();
 	}
-	
+
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return fArg1.isConstantExpression(point)
 			&& fArg2.isConstantExpression(point)
 			&& isNullOrConstexprFunc(getOverload(point));
@@ -262,7 +272,7 @@ public class EvalBinary extends CPPDependentEvaluation {
 			IType type = fArg1.getType(point);
 			type= SemanticUtil.getNestedType(type, TDEF | REF | CVTYPE);
     		if (type instanceof ICPPClassType) {
-    			return CPPSemantics.findOverloadedBinaryOperator(point, getTemplateDefinitionScope(), 
+    			return CPPSemantics.findOverloadedBinaryOperator(point, getTemplateDefinitionScope(),
     					OverloadableOperator.BRACKET, fArg1, fArg2);
     		}
 		} else {

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalComma.java

@@ -36,9 +36,11 @@ public class EvalComma extends CPPDependentEvaluation {
 	private ICPPFunction[] fOverloads;
 
 	private IType fType;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalComma(ICPPEvaluation[] evals, IASTNode pointOfDefinition) {
-		this(evals, findEnclosingTemplate(pointOfDefinition));		
+		this(evals, findEnclosingTemplate(pointOfDefinition));
 	}
 
 	public EvalComma(ICPPEvaluation[] evals, IBinding templateDefinition) {
@@ -72,9 +74,17 @@ public class EvalComma extends CPPDependentEvaluation {
 	public boolean isValueDependent() {
 		return containsDependentValue(fArguments);
 	}
-	
+
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		if (!areAllConstantExpressions(fArguments, point)) {
 			return false;
 		}

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalConditional.java

@@ -55,6 +55,8 @@ public class EvalConditional extends CPPDependentEvaluation {
 	private ValueCategory fValueCategory;
 	private IType fType;
 	private ICPPFunction fOverload;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalConditional(ICPPEvaluation condition, ICPPEvaluation positive, ICPPEvaluation negative,
 			boolean positiveThrows, boolean negativeThrows, IASTNode pointOfDefinition) {
@@ -149,6 +151,14 @@ public class EvalConditional extends CPPDependentEvaluation {
 
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return fCondition.isConstantExpression(point)
 			&& (fPositive == null || fPositive.isConstantExpression(point))
 			&& fNegative.isConstantExpression(point);
@@ -243,7 +253,7 @@ public class EvalConditional extends CPPDependentEvaluation {
 
 		// 5.16-5: At least one class type but no conversion
 		if (isClassType2 || isClassType3) {
-			fOverload = CPPSemantics.findOverloadedConditionalOperator(point, getTemplateDefinitionScope(), positive, fNegative);			
+			fOverload = CPPSemantics.findOverloadedConditionalOperator(point, getTemplateDefinitionScope(), positive, fNegative);
 			if (fOverload != null) {
 				fType= ExpressionTypes.typeFromFunctionCall(fOverload);
 			} else {

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalFixed.java

@@ -45,6 +45,8 @@ public class EvalFixed extends CPPEvaluation {
 	private boolean fCheckedIsTypeDependent;
 	private boolean fIsValueDependent;
 	private boolean fCheckedIsValueDependent;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalFixed(IType type, ValueCategory cat, IValue value) {
 		// Avoid nesting EvalFixed's as nesting causes the signature to be different.
@@ -54,7 +56,7 @@ public class EvalFixed extends CPPEvaluation {
 			cat = inner.fValueCategory;
 			value = inner.fValue;
 		}
-		
+
 		if (type instanceof CPPBasicType) {
 			Long num = value.numericalValue();
 			if (num != null) {
@@ -67,7 +69,7 @@ public class EvalFixed extends CPPEvaluation {
 		fValueCategory= cat;
 		fValue= value;
 	}
-	
+
 	public IType getType() {
 		return fType;
 	}
@@ -107,9 +109,17 @@ public class EvalFixed extends CPPEvaluation {
 		}
 		return fIsValueDependent;
 	}
-	
+
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return (fType instanceof ICPPClassType && TypeTraits.isEmpty(fType, point))
 				|| isConstexprValue(fValue, point);
 	}
@@ -180,11 +190,11 @@ public class EvalFixed extends CPPEvaluation {
 		IValue value = CPPTemplates.instantiateValue(fValue, context, maxDepth);
 		if (type == fType && value == fValue)
 			return this;
-		// If an error occurred while instantiating the value (such as a substitution failure), 
+		// If an error occurred while instantiating the value (such as a substitution failure),
 		// propagate that error.
 		if (value == Value.ERROR)
 			return EvalFixed.INCOMPLETE;
-		// Resolve the parameter pack type to the underlying type if the instantiated value is not dependent. 
+		// Resolve the parameter pack type to the underlying type if the instantiated value is not dependent.
 		if (type instanceof ICPPParameterPackType && value.numericalValue() != null)
 			type = ((ICPPParameterPackType) type).getType();
 		return new EvalFixed(type, fValueCategory, value);

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalFunctionCall.java

@@ -45,6 +45,8 @@ public class EvalFunctionCall extends CPPDependentEvaluation {
 	private final ICPPEvaluation[] fArguments;
 	private ICPPFunction fOverload= CPPFunction.UNINITIALIZED_FUNCTION;
 	private IType fType;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalFunctionCall(ICPPEvaluation[] args, IASTNode pointOfDefinition) {
 		this(args, findEnclosingTemplate(pointOfDefinition));
@@ -85,6 +87,14 @@ public class EvalFunctionCall extends CPPDependentEvaluation {
 
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return areAllConstantExpressions(fArguments, point) && isNullOrConstexprFunc(getOverload(point));
 	}
 
@@ -101,7 +111,7 @@ public class EvalFunctionCall extends CPPDependentEvaluation {
 
 		IType t= SemanticUtil.getNestedType(fArguments[0].getType(point), TDEF | REF | CVTYPE);
 		if (t instanceof ICPPClassType) {
-	    	return CPPSemantics.findOverloadedOperator(point, getTemplateDefinitionScope(), fArguments, t, 
+	    	return CPPSemantics.findOverloadedOperator(point, getTemplateDefinitionScope(), fArguments, t,
 	    			OverloadableOperator.PAREN, LookupMode.NO_GLOBALS);
 		}
 		return null;
@@ -121,7 +131,7 @@ public class EvalFunctionCall extends CPPDependentEvaluation {
 		ICPPFunction overload = getOverload(point);
 		if (overload != null)
 			return ExpressionTypes.typeFromFunctionCall(overload);
-		
+
 		ICPPEvaluation function = fArguments[0];
 		IType result = ExpressionTypes.typeFromFunctionCall(function.getType(point));
 		if (function instanceof EvalMemberAccess) {
@@ -135,7 +145,7 @@ public class EvalFunctionCall extends CPPDependentEvaluation {
 		ICPPEvaluation eval = computeForFunctionCall(new ConstexprEvaluationContext(point));
 		if (eval == this) {
 			return Value.create(eval);
-		} 
+		}
 		return eval.getValue(point);
 	}
 

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalFunctionSet.java

@@ -58,6 +58,8 @@ public class EvalFunctionSet extends CPPDependentEvaluation {
 	// by asking the first function in the set for its name.)
 	// Exactly one of fFunctionSet and fName should be non-null.
 	private final char[] fName;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalFunctionSet(CPPFunctionSet set, boolean qualified, boolean addressOf, IType impliedObjectType,
 			IASTNode pointOfDefinition) {
@@ -140,6 +142,14 @@ public class EvalFunctionSet extends CPPDependentEvaluation {
 
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		if (fFunctionSet == null)
 			return false;
 		for (ICPPFunction f : fFunctionSet.getBindings()) {

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalInitList.java

@@ -31,6 +31,8 @@ import org.eclipse.core.runtime.CoreException;
  */
 public class EvalInitList extends CPPDependentEvaluation {
 	private final ICPPEvaluation[] fClauses;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalInitList(ICPPEvaluation[] clauses, IASTNode pointOfDefinition) {
 		this(clauses, findEnclosingTemplate(pointOfDefinition));
@@ -64,9 +66,17 @@ public class EvalInitList extends CPPDependentEvaluation {
 	public boolean isValueDependent() {
 		return containsDependentValue(fClauses);
 	}
-	
+
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return areAllConstantExpressions(fClauses, point);
 	}
 

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalTypeId.java

@@ -53,6 +53,8 @@ public class EvalTypeId extends CPPDependentEvaluation {
 	private ICPPFunction fConstructor = CPPFunction.UNINITIALIZED_FUNCTION;
 	private boolean fCheckedIsTypeDependent;
 	private boolean fIsTypeDependent;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalTypeId(IType type, IASTNode pointOfDefinition, ICPPEvaluation... arguments) {
 		this(type, findEnclosingTemplate(pointOfDefinition), false, arguments);
@@ -151,6 +153,14 @@ public class EvalTypeId extends CPPDependentEvaluation {
 
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return !fRepresentsNewExpression
 				&& areAllConstantExpressions(fArguments, point)
 				&& isNullOrConstexprFunc(getConstructor(point));
@@ -298,7 +308,7 @@ public class EvalTypeId extends CPPDependentEvaluation {
 	}
 
 	@Override
-	public ICPPEvaluation computeForFunctionCall(CPPFunctionParameterMap parameterMap, 
+	public ICPPEvaluation computeForFunctionCall(CPPFunctionParameterMap parameterMap,
 			ConstexprEvaluationContext context) {
 		ICPPEvaluation[] args = fArguments;
 		for (int i = 0; i < fArguments.length; i++) {

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalUnary.java

@@ -79,6 +79,8 @@ public class EvalUnary extends CPPDependentEvaluation {
 	private final IBinding fAddressOfQualifiedNameBinding;
 	private ICPPFunction fOverload= CPPFunction.UNINITIALIZED_FUNCTION;
 	private IType fType;
+	private boolean fCheckedIsConstantExpression;
+	private boolean fIsConstantExpression;
 
 	public EvalUnary(int operator, ICPPEvaluation operand, IBinding addressOfQualifiedNameBinding,
 			IASTNode pointOfDefinition) {
@@ -149,9 +151,17 @@ public class EvalUnary extends CPPDependentEvaluation {
 			return fArgument.isValueDependent();
 		}
 	}
-	
+
 	@Override
 	public boolean isConstantExpression(IASTNode point) {
+		if (!fCheckedIsConstantExpression) {
+			fCheckedIsConstantExpression = true;
+			fIsConstantExpression = computeIsConstantExpression(point);
+		}
+		return fIsConstantExpression;
+	}
+
+	private boolean computeIsConstantExpression(IASTNode point) {
 		return fArgument.isConstantExpression(point)
 			&& isNullOrConstexprFunc(getOverload(point));
 	}
@@ -287,7 +297,7 @@ public class EvalUnary extends CPPDependentEvaluation {
 				return Value.ERROR;
 			IType targetType = parameterTypes[0];
 			arg = maybeApplyConversion(arg, targetType, point);
-			
+
 			if (!(overload instanceof CPPImplicitFunction)) {
 				if (!overload.isConstexpr())
 					return Value.ERROR;
@@ -381,7 +391,7 @@ public class EvalUnary extends CPPDependentEvaluation {
 	}
 
 	@Override
-	public ICPPEvaluation computeForFunctionCall(CPPFunctionParameterMap parameterMap, 
+	public ICPPEvaluation computeForFunctionCall(CPPFunctionParameterMap parameterMap,
 			ConstexprEvaluationContext context) {
 		ICPPEvaluation argument = fArgument.computeForFunctionCall(parameterMap, context.recordStep());
 		if (argument == fArgument)