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Bug 545756 - Improve EvalBinding.isConstantExpression()

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Previously, all variables with an initial value (even non-const)
were treated as constant expressions, now only constexpr variables,
static const members and global const variables are treated as constant expression.

Change-Id: I2acb4033a1f75110302ea25640afb070d025ec2b
Signed-off-by: Hannes Vogt <hannes@havogt.de>
This commit is contained in:
Hannes Vogt 2019-04-04 22:36:40 +02:00 • committed by Nathan Ridge
parent 480af1ddb1
commit 11a14b7ed3
6 changed files with 53 additions and 6 deletions
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12
core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
View file

@ -13031,6 +13031,18 @@ public class AST2CPPTests extends AST2CPPTestBase {
parseAndCheckImplicitNameBindings();
}
// struct A {
// int x;
// };
//
// template <typename T>
// struct B {
// A a{sizeof(T)};
// };
public void testAggregateInitNoNarrowingConversionInDependentConstContext_545756() throws Exception {
parseAndCheckImplicitNameBindings();
}
// struct type{
// int a;
// };

16
core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
View file

@ -11282,4 +11282,20 @@ public class AST2TemplateTests extends AST2CPPTestBase {
helper.assertVariableValue("val1", 42);
helper.assertVariableValue("val2", 43);
}
// template <typename T>
// constexpr T id(T a) {
// return a;
// }
//
// template <int> struct Waldo {using type = int;};
//
// const int forty_two = 42;
// using const_int_ref = int const&;
// const_int_ref ref_forty_two = forty_two;
//
// Waldo<id(ref_forty_two)>::type a;
public void testGlobalConstWorksAsConstExpression_545756() throws Exception {
parseAndCheckBindings();
}
}

2
core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPVariable.java
View file

@ -202,7 +202,7 @@ public class CPPVariable extends PlatformObject implements ICPPInternalDeclaredV
@Override
public boolean isConstexpr() {
return VariableHelpers.isConstexpr(fDefinition);
return VariableHelpers.isConstexpr(fDefinition != null ? fDefinition : fDeclarations[0]);
}
@Override

2
core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/AggregateInitialization.java
View file

@ -103,9 +103,11 @@ class AggregateInitialization {
fIndex++;
// [dcl.init.aggr] If the initializer-clause is an expression and a narrowing conversion is
// required to convert the expression, the program is ill-formed.
if (!initializer.isConstantExpression()) {
if (!(initializer instanceof EvalInitList) && costWithoutElision.isNarrowingConversion()) {
return Cost.NO_CONVERSION;
}
}
if (costWithoutElision.compareTo(worstCost) > 0) {
worstCost = costWithoutElision;
}

21
core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalBinding.java
View file

@ -32,6 +32,7 @@ import org.eclipse.cdt.core.dom.ast.IProblemBinding;
import org.eclipse.cdt.core.dom.ast.IType;
import org.eclipse.cdt.core.dom.ast.IValue;
import org.eclipse.cdt.core.dom.ast.IVariable;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPField;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPFunction;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPParameter;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPParameterPackType;
@ -257,8 +258,24 @@ public class EvalBinding extends CPPDependentEvaluation {
}
private boolean computeIsConstantExpression() {
return fBinding instanceof IEnumerator || fBinding instanceof ICPPFunction
|| (fBinding instanceof IVariable && isConstexprValue(((IVariable) fBinding).getInitialValue()));
if (fBinding instanceof IEnumerator || fBinding instanceof ICPPFunction)
return true;
else if (fBinding instanceof ICPPVariable) {
if (!isConstexprValue(((IVariable) fBinding).getInitialValue()))
return false;
ICPPVariable var = (ICPPVariable) fBinding;
if (var.isConstexpr())
return true;
IType type = SemanticUtil.getNestedType(var.getType(), SemanticUtil.TDEF | SemanticUtil.REF);
if (ExpressionTypes.isConst(type)) {
if (var instanceof ICPPField) {
if (var.isStatic())
return true;
} else
return true;
}
}
return false;
}
@Override

2
core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/ExpressionTypes.java
View file

@ -113,7 +113,7 @@ public class ExpressionTypes {
return type;
}
private static boolean isConst(IType type) {
public static boolean isConst(IType type) {
if (type instanceof IQualifierType) {
return ((IQualifierType) type).isConst();
} else if (type instanceof IPointerType) {