Add golang 1.14+ cmd/compile's native libfuzzer instrumentation support.

[inferno-chromium]

Slightly modified version of https://github.com/mdempsky/go114-fuzz-build
also uses template from gen_go_fuzz.go

[inferno-chromium]

@lukasz-milewski @mdempsky - can you help to review this. Should this go in an official go module ? This just modifies https://github.com/mdempsky/go114-fuzz-build slightly and uses fuzz template from internal gen_go_fuzz, any other changes you think we should do here before we migrate projects from @dvyukov's https://github.com/dvyukov/go-fuzz

[TravisBuddy]

Hey @inferno-chromium,
Your changes look good to me!

View build log

TravisBuddy Request Identifier: 13ff54f0-7d8e-11ea-9491-7112ce4ca887

[mdempsky]

Should this go in an official go module ?

By official Go module, do you mean like a module maintained by the Go project? Or do you mean like in a separate, standalone Go module?

I would think you can just use github.com/mdempsky/go114-fuzz-build as-is.

This just modifies https://github.com/mdempsky/go114-fuzz-build slightly and uses fuzz template from internal gen_go_fuzz, any other changes you think we should do here before we migrate projects from @dvyukov's https://github.com/dvyukov/go-fuzz

What was the motivation for these changes?

[inferno-chromium]

Should this go in an official go module ?

By official Go module, do you mean like a module maintained by the Go project? Or do you mean like in a separate, standalone Go module?

Yes an official go module maintained by Go project.

I would think you can just use github.com/mdempsky/go114-fuzz-build as-is.

Prefer to avoid user repo, prefer to use github.com/google, we will just put code in OSS-Fuzz repo.

This just modifies https://github.com/mdempsky/go114-fuzz-build slightly and uses fuzz template from internal gen_go_fuzz, any other changes you think we should do here before we migrate projects from @dvyukov's https://github.com/dvyukov/go-fuzz

What was the motivation for these changes?

Makes it easier to make minor changes, e.g. adds LLVMFuzzerInitialize, removes unneeded command line switches, makes output file mandatory.

[TravisBuddy]

Hey @inferno-chromium,
Your changes look good to me!

View build log

TravisBuddy Request Identifier: 076822d0-7db1-11ea-b89f-d9b5d34487e5

[mdempsky]

e.g. adds LLVMFuzzerInitialize,

Does adding this have any effect if the function doesn't do anything?

The //exported functions should use C.xxx types in their parameter / return types to guarantee C ABI compatibility.

[inferno-chromium]

e.g. adds LLVMFuzzerInitialize,

Does adding this have any effect if the function doesn't do anything?

Yes right, in future, we can add support for it. but no reason to keep it now. removed.

The //exported functions should use C.xxx types in their parameter / return types to guarantee C ABI compatibility.

Ok done, switched to your version.

[TravisBuddy]

Hey @inferno-chromium,
Your changes look good to me!

View build log

TravisBuddy Request Identifier: 1c8a4e00-7db5-11ea-b89f-d9b5d34487e5

[oliverchang]

LGTM, but not a fan of branching/duplicating code. Can we just clone https://github.com/mdempsky/go114-fuzz-build directly? If these changes are needed, can we just contribute them to that repo instead?

[inferno-chromium]

LGTM, but not a fan of branching/duplicating code. Can we just clone https://github.com/mdempsky/go114-fuzz-build directly? If these changes are needed, can we just contribute them to that repo instead?

Sure, removed from our repo and will ask @lukasz-milewski to upstream in an official repo. Till then better to not duplicate stuff, so removed my implementation.

[TravisBuddy]

Hey @inferno-chromium,
Your changes look good to me!

View build log

TravisBuddy Request Identifier: b01b1ef0-7ded-11ea-a704-7741d9774a61

[mdempsky]

For what it's worth, I'm the upstream maintainer of the Go compiler's libfuzzer support, and I intend to maintain mdempsky/go114-fuzz-build until there's official cmd/go integration. But I expect the latter will still be a while.

[inferno-chromium]

For what it's worth, I'm the upstream maintainer of the Go compiler's libfuzzer support, and I intend to maintain mdempsky/go114-fuzz-build until there's official cmd/go integration. But I expect the latter will still be a while.

Sure that sounds good, we will follow mdempsky/go114-fuzz-build then.

[Dor1s]

LGTM, thanks a lot!