vsapsai updated this revision to Diff 135708.
vsapsai added a comment.
- Override `This` for indirect field initializer more like it is done for
`InitListExpr`.
I rebased my changes, so the diff between different versions can be noisy.
https://reviews.llvm.org/D42498
Files:
clang/lib/AST/ExprConstant.cpp
clang/test/SemaCXX/constant-expression-cxx1y.cpp
Index: clang/test/SemaCXX/constant-expression-cxx1y.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx1y.cpp
+++ clang/test/SemaCXX/constant-expression-cxx1y.cpp
@@ -1044,3 +1044,44 @@
constexpr B b;
constexpr int p = b.n; // expected-error {{constant expression}} expected-note {{mutable}}
}
+
+namespace IndirectFields {
+
+// Reference indirect field.
+struct A {
+ struct {
+ union {
+ int x = x = 3; // expected-note {{outside its lifetime}}
+ };
+ };
+ constexpr A() {}
+};
+static_assert(A().x == 3, ""); // expected-error{{not an integral constant expression}} expected-note{{in call to 'A()'}}
+
+// Reference another indirect field, with different 'this'.
+struct B {
+ struct {
+ union {
+ int x = 3;
+ };
+ int y = x;
+ };
+ constexpr B() {}
+};
+static_assert(B().y == 3, "");
+
+// Nested evaluation of indirect field initializers.
+struct C {
+ union {
+ int x = 1;
+ };
+};
+struct D {
+ struct {
+ C c;
+ int y = c.x + 1;
+ };
+};
+static_assert(D().y == 2, "");
+
+} // namespace IndirectFields
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -4383,6 +4383,7 @@
#endif
for (const auto *I : Definition->inits()) {
LValue Subobject = This;
+ LValue SubobjectParent = This;
APValue *Value = &Result;
// Determine the subobject to initialize.
@@ -4413,7 +4414,8 @@
} else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
// Walk the indirect field decl's chain to find the object to initialize,
// and make sure we've initialized every step along it.
- for (auto *C : IFD->chain()) {
+ auto IndirectFieldChain = IFD->chain();
+ for (auto *C : IndirectFieldChain) {
FD = cast<FieldDecl>(C);
CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
// Switch the union field if it differs. This happens if we had
@@ -4429,6 +4431,10 @@
*Value = APValue(APValue::UninitStruct(), CD->getNumBases(),
std::distance(CD->field_begin(), CD->field_end()));
}
+ // Store Subobject as its parent before updating it for the last element
+ // in the chain.
+ if (C == IndirectFieldChain.back())
+ SubobjectParent = Subobject;
if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
return false;
if (CD->isUnion())
@@ -4440,10 +4446,16 @@
llvm_unreachable("unknown base initializer kind");
}
+ // Need to override This for implicit field initializers as in this case
+ // This refers to innermost anonymous struct/union containing initializer,
+ // not to currently constructed class.
+ const Expr *Init = I->getInit();
+ ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
+ isa<CXXDefaultInitExpr>(Init));
FullExpressionRAII InitScope(Info);
- if (!EvaluateInPlace(*Value, Info, Subobject, I->getInit()) ||
- (FD && FD->isBitField() && !truncateBitfieldValue(Info, I->getInit(),
- *Value, FD))) {
+ if (!EvaluateInPlace(*Value, Info, Subobject, Init) ||
+ (FD && FD->isBitField() &&
+ !truncateBitfieldValue(Info, Init, *Value, FD))) {
// If we're checking for a potential constant expression, evaluate all
// initializers even if some of them fail.
if (!Info.noteFailure())
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