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Bug 514363 - Fix constexpr evaluation of assignment into array element

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The computation had a bug where the array decayed to a pointer, and we
tried to use the pointer's value as a composite value, instead of the
underlying array's value.

Change-Id: I9510d28e04deb0b8ef835e2857f8b513d11d1d72
This commit is contained in:
Nathan Ridge 2017-11-05 23:49:47 -05:00
parent 301de3d40e
commit f1f9ddf0f7
2 changed files with 26 additions and 1 deletions
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13
core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/index/tests/IndexCPPTemplateResolutionTest.java
View file

@ -3140,4 +3140,17 @@ public class IndexCPPTemplateResolutionTest extends IndexBindingResolutionTestBa
public void testRegression_516338() throws Exception {
checkBindings();
}
// struct Foo {
// char value[1];
// constexpr Foo() : value{0} {
// value[0] = 0; // Indexer fails here.
// }
// };
// constexpr auto foo = Foo{};
// // empty file
public void testAssignmentToMemberArrayElement_514363() throws Exception {
checkBindings();
}
}

14
core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalBinary.java
View file

@ -491,7 +491,19 @@ public class EvalBinary extends CPPDependentEvaluation {
Number numericValue = fixed2.getValue().numberValue();
if (numericValue == null)
return EvalFixed.INCOMPLETE;
return new EvalCompositeAccess(fixed1, numericValue.intValue());
ICPPEvaluation composite = fixed1;
int arrayIndex = numericValue.intValue();
if (fixed1 instanceof EvalPointer) {
ICPPEvaluation elementEval = ((EvalPointer) fixed1).getTargetEvaluation();
if (elementEval instanceof EvalCompositeAccess) {
// 'composite' will now be the underlying array that the pointer points into.
// Since the pointer may not point at the beginning of the array, the array
// index needs to be shifted by the pointer's position.
composite = ((EvalCompositeAccess) elementEval).getParent();
arrayIndex += ((EvalPointer) fixed1).getPosition();
}
}
return new EvalCompositeAccess(composite, arrayIndex);
} else if ((isArray(fixed1) || isArray(fixed2)) && (hasIntType(fixed1) || hasIntType(fixed2))) {
int offset = hasIntType(fixed1) ? fixed1.getValue().numberValue().intValue() : fixed2.getValue().numberValue().intValue();
EvalCompositeAccess evalCompositeAccess = new EvalCompositeAccess(isArray(fixed1) ? fixed1 : fixed2, offset);