Stream: t-compiler

Topic: pre-meeting triage 2019-08-29 #54818


nikomatsakis (Aug 29 2019 at 13:35, on Zulip):

I will be doing pre-triage in this channel.

nikomatsakis (Aug 29 2019 at 13:38, on Zulip):

Let's start with unprioritized, nominated issues

nikomatsakis (Aug 29 2019 at 13:38, on Zulip):

There...are a lot

nikomatsakis (Aug 29 2019 at 13:40, on Zulip):

STATUS_ACCESS_VIOLATION and STATUS_HEAP_CORRUPTION during compilation #63959

nikomatsakis (Aug 29 2019 at 13:40, on Zulip):

This seems to be related #63361 and the LLVM upgrade, again. It does not happen when target-cpu is not set.

centril (Aug 29 2019 at 13:41, on Zulip):

(Is this a soundness hole?)

nikomatsakis (Aug 29 2019 at 13:41, on Zulip):

@Nikita Popov any thoughts on this?

nikomatsakis (Aug 29 2019 at 13:42, on Zulip):

I don't know what's the deal, @centril. I just posted this comment:


Checking in from @rust-lang/compiler triage:

This seems to be related to our LLVM upgrade. The linked issue (#63361) was blamed on LLVM bug 42935 and fixed by @nikic via a LLVM submodule update (#63415).

cc @nikic and @nagisa -- Any thoughts on what's going on here?

nikomatsakis (Aug 29 2019 at 13:43, on Zulip):

I guess I'll tag it P-high and add to a list ("LLVM issues") to review

centril (Aug 29 2019 at 13:43, on Zulip):

sounds good

nikomatsakis (Aug 29 2019 at 13:44, on Zulip):

mis-compilation of noreturn extern "C" definitions that unwind on stable and nightly #63943

nikomatsakis (Aug 29 2019 at 13:46, on Zulip):

It sounds like @RalfJ could add a test for this to #63909?

centril (Aug 29 2019 at 13:46, on Zulip):

I'd say this requires t-lang discussion

nikomatsakis (Aug 29 2019 at 13:47, on Zulip):

seems like it

nikomatsakis (Aug 29 2019 at 13:47, on Zulip):

let's nominate for t-lang

nikomatsakis (Aug 29 2019 at 13:47, on Zulip):

ICE on borrow check check_loans on stable #63932

centril (Aug 29 2019 at 13:48, on Zulip):

this works on nightly and beta

centril (Aug 29 2019 at 13:48, on Zulip):

and it is ICE => error

centril (Aug 29 2019 at 13:48, on Zulip):

you could stable nominate it if you want to

nikomatsakis (Aug 29 2019 at 13:48, on Zulip):

yeah, seems like we can leave it

nikomatsakis (Aug 29 2019 at 13:48, on Zulip):

should we just close it as fixed?

centril (Aug 29 2019 at 13:49, on Zulip):

if you don't think it should be stable nominated then let's close

centril (Aug 29 2019 at 13:49, on Zulip):

(where stable nomination is judged on technical merits, not whether we will do a point release ultimately)

nikomatsakis (Aug 29 2019 at 13:49, on Zulip):

YEah. I'm fine either way but I think i'll just close to save everybody effort.

centril (Aug 29 2019 at 13:50, on Zulip):

sgtm

nikomatsakis (Aug 29 2019 at 13:50, on Zulip):

Wasm code failing regression probably related to update to LLVM 9 trunk #63918

nikomatsakis (Aug 29 2019 at 13:50, on Zulip):

Blamed on an LLVM bug https://bugs.llvm.org/show_bug.cgi?id=43132

nikomatsakis (Aug 29 2019 at 13:50, on Zulip):

@Alex Crichton are you around by any chance?

nikomatsakis (Aug 29 2019 at 13:50, on Zulip):

I'm not sure what to do about this one but doesn't seem P-high

nikomatsakis (Aug 29 2019 at 13:51, on Zulip):

I'll mark as P-medium for now

nikomatsakis (Aug 29 2019 at 13:51, on Zulip):

My reasoning is that WASM is sort of a "WIP" target, but I'm not sure if that's the right way to think about things. =)

centril (Aug 29 2019 at 13:52, on Zulip):

seems right-adjacent to me =P

nikomatsakis (Aug 29 2019 at 13:52, on Zulip):

rustc could not initialize thread_rng (on pre-getrandom Linux kernel) #63848

nikomatsakis (Aug 29 2019 at 13:53, on Zulip):

Seems like the fix has something to do with rand versions

nikomatsakis (Aug 29 2019 at 13:53, on Zulip):

https://github.com/rust-lang/rust/pull/63806 is perhaps a fix?

centril (Aug 29 2019 at 13:54, on Zulip):

bummer, no backtrace :frown:

nikomatsakis (Aug 29 2019 at 13:56, on Zulip):

temporary lifetime around await is (maybe) unexpectedly short #63832

nikomatsakis (Aug 29 2019 at 13:56, on Zulip):

this is nominated for t-lang, not us

nikomatsakis (Aug 29 2019 at 13:56, on Zulip):

Miscompilation under target-cpu >= haswell #63791

nikomatsakis (Aug 29 2019 at 13:57, on Zulip):

there's been a lot of great work on minimization here

nikomatsakis (Aug 29 2019 at 13:57, on Zulip):

and a git bisect narrowed down to commit https://github.com/rust-lang/rust/commit/df0466d0bb807a7266cc8ac9931cd43b3e84b62e, which is an llvm upgrade

Nikita Popov (Aug 29 2019 at 14:00, on Zulip):

So many LLVM bugs :)

nikomatsakis (Aug 29 2019 at 14:00, on Zulip):

Yeah

nikomatsakis (Aug 29 2019 at 14:00, on Zulip):

Feels like we need a specific alias to cc "LLVM folk"

nikomatsakis (Aug 29 2019 at 15:07, on Zulip):

Returning to the nominated issues...

nikomatsakis (Aug 29 2019 at 15:07, on Zulip):

Suggest removing self import when not in a list #63741

nikomatsakis (Aug 29 2019 at 15:08, on Zulip):

nominated for t-lang, I think

nikomatsakis (Aug 29 2019 at 15:09, on Zulip):

Strange E0505 error ... is this a bug? #63719

nikomatsakis (Aug 29 2019 at 15:09, on Zulip):

Also seems like T-lang, removing T-compiler for now

nikomatsakis (Aug 29 2019 at 15:09, on Zulip):

gfx_device_gl 0.16.1 broken on latest nightly #63687

nikomatsakis (Aug 29 2019 at 15:13, on Zulip):

Hmm, this looks kinda luck a bug to me.

nikomatsakis (Aug 29 2019 at 15:16, on Zulip):

@Vadim Petrochenkov -- have you looked at #63687? Maybe it was listed also in one of the beta regressions?

nikomatsakis (Aug 29 2019 at 15:20, on Zulip):

document that target features are unsafe #63597

nikomatsakis (Aug 29 2019 at 15:20, on Zulip):

hmm, doesn't seem p-high, but seems like a good documentation issue... let me think...

nikomatsakis (Aug 29 2019 at 15:21, on Zulip):

Hey @Sergey Togi Dashnyam -- iirc you were looking for a good first PR, this might be a simple one. It's a documentation question more than anything.

nikomatsakis (Aug 29 2019 at 15:23, on Zulip):

Codegen forgets array size when used with iterators #63552

nikomatsakis (Aug 29 2019 at 15:24, on Zulip):

Optimization regression, caused by an LLVM backport which was itself fixing some other perf regression. Argh.

nikomatsakis (Aug 29 2019 at 15:25, on Zulip):

Seems unfortunate. I feel like we're going to call this P-medium. Would be nice if we had a way to "kick it" to the LLVM wg for consideration, but I know that there's no process for that (and nobody I think with enough dedicated time to keep such a pipeline going).

nikomatsakis (Aug 29 2019 at 15:26, on Zulip):

I guess I'll include it on my "focus list" for LLVM regressions.

nikomatsakis (Aug 29 2019 at 15:27, on Zulip):

Adding nom as a dependency to a proc-macro crate with tests results in link error #62146

Sergey Togi Dashnyam (Aug 29 2019 at 15:29, on Zulip):

document that target features are unsafe #63597

@nikomatsakis got it, will look into it.

nikomatsakis (Aug 29 2019 at 15:46, on Zulip):

rustc panics if a dyn is added/removed with node_id_to_type: no type for node #51716

nikomatsakis (Aug 29 2019 at 15:51, on Zulip):

incremental bug, marking as p-medium, but it's a category we should address

nikomatsakis (Aug 29 2019 at 15:51, on Zulip):

Re-enable detection of unused library #![feature] directives #44232

centril (Aug 29 2019 at 15:52, on Zulip):

nominated for both teams

nikomatsakis (Aug 29 2019 at 15:59, on Zulip):

Compiler panic compiling libcore #43982

nikomatsakis (Aug 29 2019 at 15:59, on Zulip):

@Igor Matuszewski this looks like a problem that is specific to save-analysis -- do you think you could take a look at it?

centril (Aug 29 2019 at 16:00, on Zulip):

(should we kill save_analysis or what...)

Igor Matuszewski (Aug 29 2019 at 16:01, on Zulip):

Will do

Igor Matuszewski (Aug 29 2019 at 16:03, on Zulip):

@centril hopefully in some way or another yeah, but there’s still a use case for offline code knowledge dumping facility for offline code indexing (rather than IDEs)

RalfJ (Aug 29 2019 at 16:56, on Zulip):

It sounds like RalfJ could add a test for this to #63909?

looks like I could, yes. not sure if we want to.^^

Last update: Nov 16 2019 at 02:15UTC