r184211 - PR14503: Don't assert if a constexpr constructor temploid instantiates to a

[Richard Smith]

Author: rsmith
Date: Tue Jun 18 12:51:51 2013
New Revision: 184211

URL: http://llvm.org/viewvc/llvm-project?rev=184211&view=rev
Log:
PR14503: Don't assert if a constexpr constructor temploid instantiates to a
constructor that does not initialize all members, and that constructor is used
to initialize a global.

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
    cfe/trunk/lib/AST/ExprConstant.cpp
    cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td?rev=184211&r1=184210&r2=184211&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td Tue Jun 18 12:51:51 2013
@@ -38,6 +38,8 @@ def note_constexpr_nonliteral : Note<
 def note_constexpr_non_global : Note<
   "%select{pointer|reference}0 to %select{|subobject of }1"
   "%select{temporary|%3}2 is not a constant expression">;
+def note_constexpr_uninitialized : Note<
+  "subobject of type %0 is not initialized">;
 def note_constexpr_array_index : Note<"cannot refer to element %0 of "
   "%select{array of %2 elements|non-array object}1 in a constant expression">;
 def note_constexpr_float_arithmetic : Note<

Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=184211&r1=184210&r2=184211&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Tue Jun 18 12:51:51 2013
@@ -1132,6 +1132,11 @@ static bool CheckLiteralType(EvalInfo &I
 /// check that the expression is of literal type.
 static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
                                     QualType Type, const APValue &Value) {
+  if (Value.isUninit()) {
+    Info.Diag(DiagLoc, diag::note_constexpr_uninitialized) << Type;
+    return false;
+  }
+
   // Core issue 1454: For a literal constant expression of array or class type,
   // each subobject of its value shall have been initialized by a constant
   // expression.

Modified: cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp?rev=184211&r1=184210&r2=184211&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp (original)
+++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp Tue Jun 18 12:51:51 2013
@@ -314,3 +314,23 @@ namespace CtorLookup {
   constexpr C::C(const C&) = default;
   constexpr C::C(C&) = default; // expected-error {{not constexpr}}
 }
+
+namespace PR14503 {
+  template<typename> struct V {
+    union {
+      int n;
+      struct {
+        int x,
+            y;
+      };
+    };
+    constexpr V() : x(0) {}
+  };
+
+  // The constructor is still 'constexpr' here, but the result is not intended
+  // to be a constant expression. The standard is not clear on how this should
+  // work.
+  constexpr V<int> v; // expected-error {{constant expression}} expected-note {{subobject of type 'int' is not initialized}}
+
+  constexpr int k = V<int>().x; // FIXME: ok?
+}