libsanitizer merge from upstream r175042

[Konstantin Serebryany]

The patch seems to work on a simple test. Let me digest it.
I am trying to understand if there are problems with it other than the
added complexity (which is what I don't like the most).

-Wl,-Ttext-segment=0x3600000000 does not work with binutils-gold.
gold understands -Wl,-Ttext=0x3600000000, but bfd ld doesn't.
Do you know any flag supported by both?

--kcc


On Thu, Feb 14, 2013 at 12:48 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Feb 13, 2013 at 04:19:14PM +0100, Jakub Jelinek wrote:
>> Here is the patch, works just fine for me here during asan.exp testing.
>> You can very easily either install and enable prelink on one of your
>> x86_64-linux testing boxes, or just install it and add test that
>> will say prelink -r 0x3600000000 some test shared library and then
>> just use it in sanitized program (that will also verify that you can mmap
>> libraries in that range), or even just write a test that will in a
>> non-instrumented ctor with lower priority than asan's priority
>> mmap a few pages at 0x3000000000 and close to 0x3fffff0000
>> and store some data into those buffers later on in sanitized code.
>
> I forgot you don't even need prelink -r 0x3600000000 for the testing, you
> can just link it as
> $(CXX) -shared -Wl,-Ttext-segment=0x3600000000 -fPIC -o testlib.so -fsanitize=address testlib.C
> So, put some asan tests into the executable, some tests into the shared
> library and link the executable against the shared library placed in the
> area where prelink allocates addresses to shared libraries.
> Perhaps build 3 such libraries, one at 0x3000000000, one somewhere middle
> of that range and one close to the end of the range.
>
>         Jakub