diff options
| -rw-r--r-- | include/clang/Basic/DiagnosticASTKinds.td | 3 | ||||
| -rw-r--r-- | lib/AST/ExprConstant.cpp | 12 | ||||
| -rw-r--r-- | test/CXX/expr/expr.const/p2-0x.cpp | 16 | ||||
| -rw-r--r-- | test/SemaCXX/constant-expression-cxx11.cpp | 3 |
4 files changed, 33 insertions, 1 deletions
diff --git a/include/clang/Basic/DiagnosticASTKinds.td b/include/clang/Basic/DiagnosticASTKinds.td index 9e4b63cfe8..978df36f9f 100644 --- a/include/clang/Basic/DiagnosticASTKinds.td +++ b/include/clang/Basic/DiagnosticASTKinds.td @@ -55,6 +55,9 @@ 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">; diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp index 410406788d..48e0c6f7da 100644 --- a/lib/AST/ExprConstant.cpp +++ b/lib/AST/ExprConstant.cpp @@ -2937,6 +2937,18 @@ 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); } diff --git a/test/CXX/expr/expr.const/p2-0x.cpp b/test/CXX/expr/expr.const/p2-0x.cpp index 71dc2f7104..43d683aeca 100644 --- a/test/CXX/expr/expr.const/p2-0x.cpp +++ b/test/CXX/expr/expr.const/p2-0x.cpp @@ -109,6 +109,22 @@ namespace RecursionLimits { }; } +// DR1458: taking the address of an object of incomplete class type +namespace IncompleteClassTypeAddr { + struct S; // expected-note {{forward}} + 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}} + + extern S sArr[]; + constexpr S (*p2)[] = &sArr; // ok + + struct S { + constexpr S *operator&() { return nullptr; } + }; + constexpr S *q = &s; + static_assert(!q, ""); +} + // - an operation that would have undefined behavior [Note: including, for // example, signed integer overflow (Clause 5 [expr]), certain pointer // arithmetic (5.7 [expr.add]), division by zero (5.6 [expr.mul]), or certain diff --git a/test/SemaCXX/constant-expression-cxx11.cpp b/test/SemaCXX/constant-expression-cxx11.cpp index 763c41680c..ccbc8c1abd 100644 --- a/test/SemaCXX/constant-expression-cxx11.cpp +++ b/test/SemaCXX/constant-expression-cxx11.cpp @@ -299,6 +299,7 @@ static_assert(&x > &x, "false"); // expected-error {{false}} constexpr S* sptr = &s; constexpr bool dyncast = sptr == dynamic_cast<S*>(sptr); // expected-error {{constant expression}} expected-note {{dynamic_cast}} +struct U {}; struct Str { int a : dynamic_cast<S*>(sptr) == dynamic_cast<S*>(sptr); // \ expected-warning {{not an integral constant expression}} \ @@ -315,7 +316,7 @@ struct Str { int e : (Str*)(sptr) == (Str*)(sptr); // \ expected-warning {{not an integral constant expression}} \ expected-note {{cast which performs the conversions of a reinterpret_cast is not allowed in a constant expression}} - int f : &(Str&)(*sptr) == &(Str&)(*sptr); // \ + int f : &(U&)(*sptr) == &(U&)(*sptr); // \ expected-warning {{not an integral constant expression}} \ expected-note {{cast which performs the conversions of a reinterpret_cast is not allowed in a constant expression}} int g : (S*)(void*)(sptr) == sptr; // \ |