[PATCH] Sanitize printf functions

[Yury Gribov]

================
Comment at: asan/lit_tests/TestCases/printf-2.c:2
@@ +1,3 @@
+// RUN: %clang_asan -O2 %s -o %t
+// RUN: not %t 2>&1 | FileCheck %s
+
----------------
Yury Gribov wrote:
> Yury Gribov wrote:
> > Kostya Serebryany wrote:
> > > please make these tests run in 3 modes:
> > >   ASAN_OPTIONS=check_printf=0
> > >   ASAN_OPTIONS=check_printf=1
> > >   ASAN_OPTIONS=""
> > > 
> > > we need to test that the flag affects the behavior and that it's default value is what we expect it to be.
> > > 
> > > (use FileCheck --check-prefix=CHECK-ON and --check-prefix=CHECK-OFF)
> > Ok.
> BTW how do you suggest the check_printf=0 case? In my understanding we'll have UB with absolutely unpredictable behavior...
> That's not that bad.
> If you allocate a heap block using asan's allocator,
> the behavior of an uncheck-ed out-of-bounds read is quite predictable

I tend to agree but e.g. GCC team tends to reject tests that trigger UB. Also things like this tend to be rather unstable with respect to glibc/kernel versions.

I'll do this if you're adamant though.



http://llvm-reviews.chandlerc.com/D2480