Add an "asan" bazel config to debug crashes

[CodingCanuck]

This allows you to build targets or tests with --config=asan and get
detailed debugging information for bad memory access.

Adding this in dev-tools so it can be easily shared across repos: we'll
use this a lot for any C++ development.

[benh]

Ad discussed synchronously, let's add some comments here as to which permutation of compiler + operating system this is for, e.g., Linux + gcc or macOS + clang, etc.

Also dropping this in case it's helpful: https://github.com/envoyproxy/envoy/blob/main/.bazelrc#L62

[CodingCanuck]

@onelxj Ben mentioned you might be interested in this.

Sample use of this PR: https://github.com/reboot-dev/respect/pull/69

[CodingCanuck]

Ad discussed synchronously, let's add some comments here as to which permutation of compiler + operating system this is for, e.g., Linux + gcc or macOS + clang, etc.

Done (though I don't know if the bazel default is to compile with gcc or llvm/clang):

# As of 2020/02/15, this has been tested on linux with the bazel default C++
# compiler.

Also dropping this in case it's helpful: https://github.com/envoyproxy/envoy/blob/main/.bazelrc#L62

Thanks!

That does a lot of envoy-specific stuff, e.g.:

# ASAN install its signal handler, disable ours so the stacktrace will be printed by ASAN
build:asan --define signal_trace=disabled
build:asan --define ENVOY_CONFIG_ASAN=1

I'd be curious if the minimal asan config in this PR works across several environments, though I don't have any experience building / running on other OSs.

[rjhuijsman]

Very excited about this! 🎉

[CodingCanuck]

@benh you mentioned that there might be something like a built in --features=asan or similar: do you have any links about that? It doesn't work on my first try.

Specifically, this command (which relies on the new config introduced by this PR) produces an asan error about a stack-buffer-overflow when run in the respect repo:

dazel run --config=asan //test/object-store:test

Whereas this command runs, but doesn't produce any asan-like output:

dazel run --features=asan //test/object-store:test

Sample output:

[ RUN      ] ObjectStoreTest.Fill_BadIdFills
unknown file: Failure
Unknown C++ exception thrown in the test body.
[  FAILED  ] ObjectStoreTest.Fill_BadIdFills (7 ms)

[benh]

I believe the --features=asan was first discovered here. But a little spelunking makes it look like this "feature" was only added for macOS? Maybe something for us to keep our eye on to see if it gets added in a more first-class capacity.