From: Nick Lewycky <nicholas@mxc.ca>
Date: Mon, 1 May 2017 02:03:23 +0000 (+0000)
Subject: Handle expressions with non-literal types like ignored expressions if we are supposed... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=02552ffef539b814470475718d7b0f78c02e7083;p=clang

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.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@301785 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 75bb0cac51..c99ccb6f1f 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -2169,6 +2169,9 @@ static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
   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 &Info, const Expr *E, APValue &Result) {
   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;
diff --git a/test/Sema/integer-overflow.c b/test/Sema/integer-overflow.c
index 62ee33e3d1..2f5747dd0b 100644
--- a/test/Sema/integer-overflow.c
+++ b/test/Sema/integer-overflow.c
@@ -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)));
diff --git a/test/SemaCXX/constant-expression-cxx11.cpp b/test/SemaCXX/constant-expression-cxx11.cpp
index 4abbc8e928..2a5e80adf8 100644
--- a/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/test/SemaCXX/constant-expression-cxx11.cpp
@@ -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 {};