Add a test for vcall on a null ptr.

Summary:
Turns out that in the case of -fsanitize=null and a virtual call,
the type check was generated *after* reading from vtable, which
causes a non-interpretable segfault. The check has been moved up
in https://reviews.llvm.org/D26559 and this CL adds a test for this case.

Reviewers: pcc

Subscribers: cfe-commits, kubabrecka

Differential Revision: https://reviews.llvm.org/D26560

llvm-svn: 287578

compiler-rt/test/ubsan/TestCases/TypeCheck/null.cpp

@@ -1,20 +1,34 @@
-// RUN: %clangxx -fsanitize=null %s -O3 -o %t
-// RUN: %run %t l 2>&1 | FileCheck %s --check-prefix=CHECK-LOAD
-// RUN: %expect_crash %run %t s 2>&1 | FileCheck %s --check-prefix=CHECK-STORE
-// RUN: %run %t r 2>&1 | FileCheck %s --check-prefix=CHECK-REFERENCE
-// RUN: %run %t m 2>&1 | FileCheck %s --check-prefix=CHECK-MEMBER
-// RUN: %run %t f 2>&1 | FileCheck %s --check-prefix=CHECK-MEMFUN
+// RUN: %clangxx -fsanitize=null -fno-sanitize-recover=null %s -O3 -o %t
+// RUN: not %run %t l 2>&1 | FileCheck %s --check-prefix=CHECK-LOAD
+// RUN: not %run %t s 2>&1 | FileCheck %s --check-prefix=CHECK-STORE
+// RUN: not %run %t r 2>&1 | FileCheck %s --check-prefix=CHECK-REFERENCE
+// RUN: not %run %t m 2>&1 | FileCheck %s --check-prefix=CHECK-MEMBER
+// RUN: not %run %t f 2>&1 | FileCheck %s --check-prefix=CHECK-MEMFUN
+// RUN: not %run %t t 2>&1 | FileCheck %s --check-prefix=CHECK-VCALL
+// RUN: not %run %t u 2>&1 | FileCheck %s --check-prefix=CHECK-VCALL2
 
 struct S {
   int f() { return 0; }
   int k;
 };
 
+struct T {
+  virtual int v() { return 1; }
+};
+
+struct U : T {
+  virtual int v() { return 2; }
+};
+
 int main(int, char **argv) {
   int *p = 0;
   S *s = 0;
+  T *t = 0;
+  U *u = 0;
 
   (void)*p; // ok!
+  (void)*t; // ok!
+  (void)*u; // ok!
 
   switch (argv[1][0]) {
   case 'l':
@@ -34,5 +48,11 @@ int main(int, char **argv) {
   case 'f':
     // CHECK-MEMFUN: null.cpp:[[@LINE+1]]:15: runtime error: member call on null pointer of type 'S'
     return s->f();
+  case 't':
+    // CHECK-VCALL: null.cpp:[[@LINE+1]]:15: runtime error: member call on null pointer of type 'T'
+    return t->v();
+  case 'u':
+    // CHECK-VCALL2: null.cpp:[[@LINE+1]]:15: runtime error: member call on null pointer of type 'U'
+    return u->v();
   }
 }