r301785 - Handle expressions with non-literal types like ignored expressions if we are supposed to continue evaluating them.

[Nick Lewycky via cfe-commits]

Author: nicholas
Date: Sun Apr 30 21:03:23 2017
New Revision: 301785

URL: http://llvm.org/viewvc/llvm-project?rev=301785&view=rev
Log:
Handle expressions with non-literal types like ignored expressions if we are 
supposed to continue evaluating them.

Also fix a crash casting a derived nullptr to a virtual base.

Modified:
    cfe/trunk/lib/AST/ExprConstant.cpp
    cfe/trunk/test/Sema/integer-overflow.c
    cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp

Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: 
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=301785&r1=301784&r2=301785&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Sun Apr 30 21:03:23 2017
@@ -2169,6 +2169,9 @@ static bool HandleLValueBase(EvalInfo &I
   if (!Base->isVirtual())
     return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
 
+  if (!Obj.checkNullPointer(Info, E, CSK_Base))
+    return false;
+
   SubobjectDesignator &D = Obj.Designator;
   if (D.Invalid)
     return false;
@@ -9913,8 +9916,11 @@ static bool EvaluateAsRValue(EvalInfo &I
   if (E->getType().isNull())
     return false;
 
-  if (!CheckLiteralType(Info, E))
+  if (!CheckLiteralType(Info, E)) {
+    if (Info.noteFailure())
+      EvaluateIgnoredValue(Info, E);
     return false;
+  }
 
   if (!::Evaluate(Result, Info, E))
     return false;

Modified: cfe/trunk/test/Sema/integer-overflow.c
URL: 
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/integer-overflow.c?rev=301785&r1=301784&r2=301785&view=diff
==============================================================================
--- cfe/trunk/test/Sema/integer-overflow.c (original)
+++ cfe/trunk/test/Sema/integer-overflow.c Sun Apr 30 21:03:23 2017
@@ -149,16 +149,16 @@ uint64_t check_integer_overflows(int i)
 
 // expected-warning@+2 {{overflow in expression; result is 536870912 with type 
'int'}}
   uint64_t *b;
-  uint64_t b2 = b[4608 * 1024 * 1024] + 1;
+  (void)b[4608 * 1024 * 1024] + 1;
 
 // expected-warning@+1 2{{overflow in expression; result is 536870912 with 
type 'int'}}
-  int j1 = i ? (4608 * 1024 * 1024) : (4608 * 1024 * 1024);
+  (void)(i ? (4608 * 1024 * 1024) : (4608 * 1024 * 1024));
 
 // expected-warning@+1 {{overflow in expression; result is 536870912 with type 
'int'}}
-  int j2 = -(4608 * 1024 * 1024);
+  (void)(-(4608 * 1024 * 1024));
 
 // expected-warning@+1 {{overflow in expression; result is 536870912 with type 
'int'}}
-  uint64_t j3 = b[4608 * 1024 * 1024];
+  (void)b[4608 * 1024 * 1024];
 
 // expected-warning@+1 2{{overflow in expression; result is 536870912 with 
type 'int'}}
   return ((4608 * 1024 * 1024) + ((uint64_t)(4608 * 1024 * 1024)));

Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
URL: 
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=301785&r1=301784&r2=301785&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
+++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Sun Apr 30 21:03:23 
2017
@@ -60,6 +60,10 @@ namespace DerivedToVBaseCast {
   static_assert((U*)&d == w, "");
   static_assert((U*)&d == x, "");
 
+  // expected-error@+2 {{constexpr variable 'a' must be initialized by a 
constant expression}}
+  // expected-warning@+1 {{binding dereferenced null pointer to reference has 
undefined behavior}}
+  constexpr A &a = *((B*)0);  // expected-note {{cannot access base class of 
null pointer}}
+
   struct X {};
   struct Y1 : virtual X {};
   struct Y2 : X {};


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