Heartbleed example does not work out of the box.

I was going over the documentation on this page: https://google.github.io/clusterfuzz/setting-up-fuzzing/heartbleed-example/

To do that I first followed the pre-requisites section here: https://google.github.io/clusterfuzz/setting-up-fuzzing/libfuzzer-and-afl/#compiler

That recommends installing clang 6.0 or greater. I installed it via apt and got clang version 6.0.0-1ubuntu2 as output by clang -v

The example handshake-fuzzer.cc does not compile out of the box with that version of clang as I believe it only supports the filesystem extension as experimental feature.

When I try to run the build step from the documentation:

/usr/bin/clang++ -g handshake-fuzzer.cc -fsanitize=address,fuzzer openssl-1.0.1f/libssl.a openssl-1.0.1f/libcrypto.a -std=c++17 -Iopenssl-1.0.1f/include/ -lstdc++fs -ldl -lstdc++ -o handshake-fuzzer

I get this error:

handshake-fuzzer.cc:25:10: fatal error: 'filesystem' file not found
#include <filesystem>
         ^~~~~~~~~~~~
1 error generated.

This can be fixed by changing the include to experimental/filesystem and then changing the using statement below to also include experimental at the right spot - but I imagine that will break the build on later versions of clang (I haven’t tested).

A proper fix likely involves using an API that’s available in clang 6 (though it may be more verbose).

[oliverchang]

Maybe we can just use some ifdef here? @jonathanmetzman

[jonathanmetzman]

Thanks! Just to be clear this wont work with clang5, I was just pointing out that the filesystem part of the example with clang5 (but I need to use -std=c++1z), so I assumed it work in clang6.