/*
 * This document explain how to run analyse the virglrenderer
 * code base using ASAN, the address sanitizer tools include
 * in Clang and gcc.
 */

VIRGLRENDERER:

Compiling virglrenderer with the following flags:
`-fsanitize=address`
or
`-fsanitize=memory`
Sadly, we can't use both of them in the same time.

For example,
```
export CFLAGS="-fsanitize=address -fno-omit-frame-pointer"
export CXXFLAGS="-fsanitize=address -fno-omit-frame-pointer"
mkdir build && cd build
../autogen.sh --prefix=/home/user/virglrenderer/install --enable-debug
make
```

The `-fsanitize=leak` flag don't have to be add for Linux as
it is set by default. This flag can be add to the toolchain of other platform.


MESA:

Since mesa unloads the drivers before a program finished, but ASAN only
resolves stack traces at the end. It is almost impossible to get meaningful
backtraces and so check whether the culprit is mesa or virglrenderer.
Hence, it is useful to override *dlclose* by pre-loading a shared library
that implements a stub, e.g. like:
```
int dlclose(void *handle) {
        return 0;
}
```
It seems that you need to pre-load ASAN before your dummie library.
`export LD_PRELOAD="/usr/lib64/gcc/x86_64-pc-linux-gnu/7.3.0/libasan.so $HOME/libfake-dlclose.so"`


VTEST:

Then run virglrenderer with the following flag:
`ASAN_SYMBOLIZER_PATH=/usr/bin/llvm-symbolizer`
On platform other than Linux, `ASAN_OPTIONS=detect_leaks=1`
should be added.

Start the vtest server with the command:
`ASAN_SYMBOLIZER_PATH=/usr/bin/llvm-symbolizer ./virgl_test_server`

Then connect to the server
```
export LIBGL_ALWAYS_SOFTWARE=true
export GALLIUM_DRIVER=virpipe
```

Run any payload.