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Update to new resolution for DR1458. When taking the address of an object of 

incomplete class type which has an overloaded operator&, it's now just
unspecified whether the overloaded operator or the builtin is used.

llvm-svn: 150234
This commit is contained in:
Richard Smith 2012-02-10 07:41:06 +00:00
parent 09fc1bb605
commit 0cd4ab194b
3 changed files with 4 additions and 18 deletions
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3
clang/include/clang/Basic/DiagnosticASTKinds.td
View File

@ -55,9 +55,6 @@ def note_constexpr_pointer_comparison_differing_access : Note<
"specifiers (%1 vs %3) has unspecified value">;
def note_constexpr_compare_virtual_mem_ptr : Note<
"comparison of pointer to virtual member function %0 has unspecified value">;
def note_constexpr_addr_of_incomplete : Note<
"cannot take address of object of incomplete class type %0 "
"in a constant expression">;
def note_constexpr_past_end : Note<
"dereferenced pointer past the end of %select{|subobject of }0"
"%select{temporary|%2}1 is not a constant expression">;

12
clang/lib/AST/ExprConstant.cpp
View File

@ -2944,18 +2944,6 @@ bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
}
bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
QualType SrcTy = E->getSubExpr()->getType();
// In C++, taking the address of an object of incomplete class type has
// undefined behavior if the complete class type has an overloaded operator&.
// DR1458 makes such expressions non-constant.
if (Info.getLangOpts().CPlusPlus &&
SrcTy->isRecordType() && SrcTy->isIncompleteType()) {
const RecordType *RT = SrcTy->getAs<RecordType>();
Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_addr_of_incomplete, 1)
<< SrcTy;
Info.Note(RT->getDecl()->getLocation(), diag::note_forward_declaration)
<< RT->getDecl();
}
return EvaluateLValue(E->getSubExpr(), Result, Info);
}

7
clang/test/CXX/expr/expr.const/p2-0x.cpp
View File

@ -111,9 +111,10 @@ namespace RecursionLimits {
// DR1458: taking the address of an object of incomplete class type
namespace IncompleteClassTypeAddr {
struct S; // expected-note {{forward}}
struct S;
extern S s;
constexpr S *p = &s; // expected-error {{constant expression}} expected-note {{cannot take address of object of incomplete class type 'IncompleteClassTypeAddr::S' in a constant expression}}
constexpr S *p = &s; // ok
static_assert(p, "");
extern S sArr[];
constexpr S (*p2)[] = &sArr; // ok
@ -121,7 +122,7 @@ namespace IncompleteClassTypeAddr {
struct S {
constexpr S *operator&() { return nullptr; }
};
constexpr S *q = &s;
constexpr S *q = &s; // ok
static_assert(!q, "");
}