r374465 - PR43629: Fix crash evaluating constexpr placement new on a subobject of

[Richard Smith via cfe-commits]

Author: rsmith
Date: Thu Oct 10 15:31:17 2019
New Revision: 374465

URL: http://llvm.org/viewvc/llvm-project?rev=374465&view=rev
Log:
PR43629: Fix crash evaluating constexpr placement new on a subobject of
an out-of-lifetime object.

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
    cfe/trunk/lib/AST/ExprConstant.cpp
    cfe/trunk/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td?rev=374465&r1=374464&r2=374465&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td Thu Oct 10 15:31:17 2019
@@ -126,7 +126,8 @@ def note_constexpr_lifetime_ended : Note
   "%plural{8:storage duration|:lifetime}0 has ended">;
 def note_constexpr_access_uninit : Note<
   "%select{read of|read of|assignment to|increment of|decrement of|"
-  "member call on|dynamic_cast of|typeid applied to|<ERRPR>|destruction of}0 "
+  "member call on|dynamic_cast of|typeid applied to|"
+  "construction of subobject of|destruction of}0 "
   "%select{object outside its lifetime|uninitialized object}1 "
   "is not allowed in a constant expression">;
 def note_constexpr_use_uninit_reference : Note<

Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=374465&r1=374464&r2=374465&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Thu Oct 10 15:31:17 2019
@@ -3178,7 +3178,7 @@ findSubobject(EvalInfo &Info, const Expr
   // Walk the designator's path to find the subobject.
   for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
     // Reading an indeterminate value is undefined, but assigning over one is OK.
-    if ((O->isAbsent() && handler.AccessKind != AK_Construct) ||
+    if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
         (O->isIndeterminate() && handler.AccessKind != AK_Construct &&
          handler.AccessKind != AK_Assign &&
          handler.AccessKind != AK_ReadObjectRepresentation)) {

Modified: cfe/trunk/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp?rev=374465&r1=374464&r2=374465&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp (original)
+++ cfe/trunk/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp Thu Oct 10 15:31:17 2019
@@ -166,3 +166,13 @@ constexpr bool construct_after_lifetime(
   return true;
 }
 static_assert(construct_after_lifetime()); // expected-error {{}} expected-note {{in call}}
+
+constexpr bool construct_after_lifetime_2() {
+  struct A { struct B {} b; };
+  A a;
+  a.~A();
+  std::construct_at<A::B>(&a.b); // expected-note {{in call}}
+  // expected-note@#new {{construction of subobject of object outside its lifetime is not allowed in a constant expression}}
+  return true;
+}
+static_assert(construct_after_lifetime_2()); // expected-error {{}} expected-note {{in call}}