Change --crate-type metadata to --emit=metadata #38571

nrc · 2016-12-23T06:59:04Z

WIP

rust-highfive · 2016-12-23T06:59:15Z

r? @nikomatsakis

(rust_highfive has picked a reviewer for you, use r? to override)

alexcrichton · 2016-12-25T21:38:37Z

Sounds like a great solution to the metadata-lib/metadata-bin problem to me!

I think we may want to keep --crate-type metadata for a cycle or so though as Cargo's currently relying on it?

nikomatsakis · 2016-12-27T16:07:44Z

👍

nrc · 2016-12-27T21:13:55Z

r? @alexcrichton

alexcrichton · 2016-12-27T23:06:49Z

Looks good to me! My only comment is that I think there's a few places where --emit link,metadata will go awry. That is, I think that'd only emit metadata rather than both.

Otherwise I'm curious what others think about the changes to --crate-type and trying to preserve backcompat here. I'm leaning towards reverting the addition of --crate-type metadata on beta as well as cargo check on beta. We can land this PR, fix Cargo, fix the other assorted Cargo bugs associated with cargo check, and then let it ride the trains through on 1.16.

If we take that route I think we can avoid the --crate-type deprecation warning here and just make the change, but if we don't take that route then we'll need to leave the deprecation warning in.

nrc · 2016-12-28T01:28:11Z

My only comment is that I think there's a few places where --emit link,metadata will go awry. That is, I think that'd only emit metadata rather than both.

This was intentional (although I admit it is sub-optimal). Basically, it seemed very difficult to make the compiler backend emit multiple artefacts, so I chose that --emit=metadata should override any other emit kinds (this only affects obj/link/other emit kinds that reach the compiler backend). This seems sensible - there is no point in emitting metadata and any other backend artefact, since the latter will always include the metadata. We could warn about this, I guess?

I was imagining pushing this to beta, rather than reverting --crate-type=metadata and landing this on nightly, but I don't mind the more conservative approach. I think we need the deprecated --crate-type just until we land a fix to Cargo (which I'm currently working on) otherwise we'll get Cargo test breakage (which I think will block this PR landing). (Oh, we could remove cargo check first, but that makes landing the Cargo fix a little bit more effort).

alexcrichton · 2016-12-28T17:03:09Z

@nrc I'd be wary of having --emit metadata perform differently than other requests like --emit dep-info,link. Although it may be rare, we'll inevitably receive a bug report about --emit metadata,link not working and I think it'd be good to head off that report here.

I think it also may not be too hard to support, right? There's a few clauses that short-circuit lots of extra work throughout this PR, but couldn't those clauses just change to "short circuit if we're only producing metadata" ? That way we'd just fall through all the normal code paths and if you happened to pass --emit metadata,link we'd fall through and at one point emit metadata in addition to final binary.

Let's discuss the strategy for beta on a future PR (or on a discussion focused on beta-nomination of this PR), though, don't want to bog it down!

nrc · 2016-12-28T20:17:27Z

"short circuit if we're only producing metadata"

This doesn't work because we want to ignore emit kinds which are emitted before we hit the backend, e.g., --emit=metadata,dep-info (which Cargo uses a lot) should trigger these paths. It should be possible to handle this, but it is not trivial.

alexcrichton · 2016-12-28T23:36:20Z

@nrc perhaps the checks could be "if link is present, take this code path"?

I'll comment on the branches I'm thinking about specifically

alexcrichton · 2016-12-28T23:36:41Z

src/librustc/middle/dependency_format.rs

@@ -103,6 +103,10 @@ pub fn calculate(sess: &session::Session) {

 fn calculate_type(sess: &session::Session,
                  ty: config::CrateType) -> DependencyList {
+    if sess.opts.output_types.contains_key(&config::OutputType::Metadata) {


Here I think we could just say that if the outputs contain link we can take the paths below, right?

alexcrichton · 2016-12-28T23:37:00Z

src/librustc/session/config.rs

@@ -1558,7 +1566,13 @@ pub fn parse_crate_types_from_list(list_list: Vec<String>) -> Result<Vec<CrateTy
                "cdylib"    => CrateTypeCdylib,
                "bin"       => CrateTypeExecutable,
                "proc-macro" => CrateTypeProcMacro,
-                "metadata"  => CrateTypeMetadata,
+                // FIXME(#38640) remove this when Cargo is fixed.


Given our discussion today during triage, I think we can remove this entirely

alexcrichton · 2016-12-28T23:37:44Z

src/librustc_trans/back/link.rs

@@ -191,7 +191,8 @@ pub fn link_binary(sess: &Session,
    let mut out_filenames = Vec::new();
    for &crate_type in sess.crate_types.borrow().iter() {
        // Ignore executable crates if we have -Z no-trans, as they will error.
-        if sess.opts.debugging_opts.no_trans &&
+        if (sess.opts.debugging_opts.no_trans ||
+            sess.opts.output_types.contains_key(&OutputType::Metadata)) &&


Here we could just check for !contains(Exe), right?

alexcrichton · 2016-12-28T23:38:35Z

src/librustc_trans/back/link.rs

+
+    if outputs.outputs.contains_key(&OutputType::Metadata) {
+        return outputs.out_directory.join(&format!("lib{}.rmeta", libname));
+    }


This is where it may get a little tricky perhaps? It seems that the request for a metadata filename may want to be plumbed farther throughout the backend?

alexcrichton · 2016-12-28T23:39:27Z

src/librustc_trans/back/link.rs

-            link_natively(sess, crate_type, &objects, &out_filename, trans,
-                          outputs, tmpdir.path());
+    if outputs.outputs.contains_key(&OutputType::Metadata) {
+        emit_metadata(sess, trans, &out_filename);


These could just be two if statements, right?

if metadata_requested { emit_metadata(...); } if link_requested { ... }

Closes 38273

…t=metadata + a warning

nrc · 2016-12-29T05:21:33Z

r? @alexcrichton can handle --emit=metadata + something else now.

Whether we remove the CrateTypeMetadata variant depends on how we handle Cargo, and I'm not sure where we're at there - I think it would be easier to remove check on beta and leave it as is on nightly (I have a PR ready for that once this lands), then we can fixup nightly pretty quickly, but that would be easier based on top of current Cargo, rather than Cargo without check.

Requires rust-lang/rust#38571

alexcrichton · 2016-12-29T07:04:43Z

@bors: r+

Ok looks good to me! We can remove --crate-type=metadata as soon as Cargo is updated.

bors · 2016-12-29T07:04:44Z

📌 Commit b059a80 has been approved by alexcrichton

bors · 2016-12-29T11:01:01Z

⌛ Testing commit b059a80 with merge e571f2d...

Change --crate-type metadata to --emit=metadata WIP

bors · 2016-12-29T13:40:10Z

☀️ Test successful - status-appveyor, status-travis
Approved by: alexcrichton
Pushing e571f2d to master...

@alexcrichton

cargo check: use --emit=metadata rather than --crate-type=metadata Requires rust-lang/rust#38571 (don't land before that does) r? @alexcrichton

Requires rust-lang/rust#38571

@alexcrichton

cargo check: use --emit=metadata rather than --crate-type=metadata Requires rust-lang/rust#38571 (don't land before that does) r? @alexcrichton

Version 1.16.0 (2017-03-16) =========================== Language -------- * Lifetimes in statics and consts default to `'static`. [RFC 1623] * [The compiler's `dead_code` lint now accounts for type aliases][38051]. * [Uninhabitable enums (those without any variants) no longer permit wildcard match patterns][38069] * [Clean up semantics of `self` in an import list][38313] * [`Self` may appear in `impl` headers][38920] * [`Self` may appear in struct expressions][39282] Compiler -------- * [`rustc` now supports `--emit=metadata`, which causes rustc to emit a `.rmeta` file containing only crate metadata][38571]. This can be used by tools like the Rust Language Service to perform metadata-only builds. * [Levenshtein based typo suggestions now work in most places, while previously they worked only for fields and sometimes for local variables][38927]. Together with the overhaul of "no resolution"/"unexpected resolution" errors (#[38154]) they result in large and systematic improvement in resolution diagnostics. * [Fix `transmute::<T, U>` where `T` requires a bigger alignment than `U`][38670] * [rustc: use -Xlinker when specifying an rpath with ',' in it][38798] * [`rustc` no longer attempts to provide "consider using an explicit lifetime" suggestions][37057]. They were inaccurate. Stabilized APIs --------------- * [`VecDeque::truncate`] * [`VecDeque::resize`] * [`String::insert_str`] * [`Duration::checked_add`] * [`Duration::checked_sub`] * [`Duration::checked_div`] * [`Duration::checked_mul`] * [`str::replacen`] * [`str::repeat`] * [`SocketAddr::is_ipv4`] * [`SocketAddr::is_ipv6`] * [`IpAddr::is_ipv4`] * [`IpAddr::is_ipv6`] * [`Vec::dedup_by`] * [`Vec::dedup_by_key`] * [`Result::unwrap_or_default`] * [`<*const T>::wrapping_offset`] * [`<*mut T>::wrapping_offset`] * `CommandExt::creation_flags` * [`File::set_permissions`] * [`String::split_off`] Libraries --------- * [`[T]::binary_search` and `[T]::binary_search_by_key` now take their argument by `Borrow` parameter][37761] * [All public types in std implement `Debug`][38006] * [`IpAddr` implements `From<Ipv4Addr>` and `From<Ipv6Addr>`][38327] * [`Ipv6Addr` implements `From<[u16; 8]>`][38131] * [Ctrl-Z returns from `Stdin.read()` when reading from the console on Windows][38274] * [std: Fix partial writes in `LineWriter`][38062] * [std: Clamp max read/write sizes on Unix][38062] * [Use more specific panic message for `&str` slicing errors][38066] * [`TcpListener::set_only_v6` is deprecated][38304]. This functionality cannot be achieved in std currently. * [`writeln!`, like `println!`, now accepts a form with no string or formatting arguments, to just print a newline][38469] * [Implement `iter::Sum` and `iter::Product` for `Result`][38580] * [Reduce the size of static data in `std_unicode::tables`][38781] * [`char::EscapeDebug`, `EscapeDefault`, `EscapeUnicode`, `CaseMappingIter`, `ToLowercase`, `ToUppercase`, implement `Display`][38909] * [`Duration` implements `Sum`][38712] * [`String` implements `ToSocketAddrs`][39048] Cargo ----- * [The `cargo check` command does a type check of a project without building it][cargo/3296] * [crates.io will display CI badges from Travis and AppVeyor, if specified in Cargo.toml][cargo/3546] * [crates.io will display categories listed in Cargo.toml][cargo/3301] * [Compilation profiles accept integer values for `debug`, in addition to `true` and `false`. These are passed to `rustc` as the value to `-C debuginfo`][cargo/3534] * [Implement `cargo --version --verbose`][cargo/3604] * [All builds now output 'dep-info' build dependencies compatible with make and ninja][cargo/3557] * [Build all workspace members with `build --all`][cargo/3511] * [Document all workspace members with `doc --all`][cargo/3515] * [Path deps outside workspace are not members][cargo/3443] Misc ---- * [`rustdoc` has a `--sysroot` argument that, like `rustc`, specifies the path to the Rust implementation][38589] * [The `armv7-linux-androideabi` target no longer enables NEON extensions, per Google's ABI guide][38413] * [The stock standard library can be compiled for Redox OS][38401] * [Rust has initial SPARC support][38726]. Tier 3. No builds available. * [Rust has experimental support for Nvidia PTX][38559]. Tier 3. No builds available. * [Fix backtraces on i686-pc-windows-gnu by disabling FPO][39379] Compatibility Notes ------------------- * [Uninhabitable enums (those without any variants) no longer permit wildcard match patterns][38069] * In this release, references to uninhabited types can not be pattern-matched. This was accidentally allowed in 1.15. * [The compiler's `dead_code` lint now accounts for type aliases][38051]. * [Ctrl-Z returns from `Stdin.read()` when reading from the console on Windows][38274] * [Clean up semantics of `self` in an import list][38313] [37057]: rust-lang/rust#37057 [37761]: rust-lang/rust#37761 [38006]: rust-lang/rust#38006 [38051]: rust-lang/rust#38051 [38062]: rust-lang/rust#38062 [38062]: rust-lang/rust#38622 [38066]: rust-lang/rust#38066 [38069]: rust-lang/rust#38069 [38131]: rust-lang/rust#38131 [38154]: rust-lang/rust#38154 [38274]: rust-lang/rust#38274 [38304]: rust-lang/rust#38304 [38313]: rust-lang/rust#38313 [38314]: rust-lang/rust#38314 [38327]: rust-lang/rust#38327 [38401]: rust-lang/rust#38401 [38413]: rust-lang/rust#38413 [38469]: rust-lang/rust#38469 [38559]: rust-lang/rust#38559 [38571]: rust-lang/rust#38571 [38580]: rust-lang/rust#38580 [38589]: rust-lang/rust#38589 [38670]: rust-lang/rust#38670 [38712]: rust-lang/rust#38712 [38726]: rust-lang/rust#38726 [38781]: rust-lang/rust#38781 [38798]: rust-lang/rust#38798 [38909]: rust-lang/rust#38909 [38920]: rust-lang/rust#38920 [38927]: rust-lang/rust#38927 [39048]: rust-lang/rust#39048 [39282]: rust-lang/rust#39282 [39379]: rust-lang/rust#39379 [`<*const T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset [`<*mut T>::wrapping_offset`]: https://doc.rust-lang.org/std/primitive.pointer.html#method.wrapping_offset [`Duration::checked_add`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_add [`Duration::checked_div`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_div [`Duration::checked_mul`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_mul [`Duration::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.checked_sub [`File::set_permissions`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.set_permissions [`IpAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv4 [`IpAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.IpAddr.html#method.is_ipv6 [`Result::unwrap_or_default`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_or_default [`SocketAddr::is_ipv4`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv4 [`SocketAddr::is_ipv6`]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html#method.is_ipv6 [`String::insert_str`]: https://doc.rust-lang.org/std/string/struct.String.html#method.insert_str [`String::split_off`]: https://doc.rust-lang.org/std/string/struct.String.html#method.split_off [`Vec::dedup_by_key`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by_key [`Vec::dedup_by`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.dedup_by [`VecDeque::resize`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.resize [`VecDeque::truncate`]: https://doc.rust-lang.org/std/collections/vec_deque/struct.VecDeque.html#method.truncate [`str::repeat`]: https://doc.rust-lang.org/std/primitive.str.html#method.repeat [`str::replacen`]: https://doc.rust-lang.org/std/primitive.str.html#method.replacen [cargo/3296]: rust-lang/cargo#3296 [cargo/3301]: rust-lang/cargo#3301 [cargo/3443]: rust-lang/cargo#3443 [cargo/3511]: rust-lang/cargo#3511 [cargo/3515]: rust-lang/cargo#3515 [cargo/3534]: rust-lang/cargo#3534 [cargo/3546]: rust-lang/cargo#3546 [cargo/3557]: rust-lang/cargo#3557 [cargo/3604]: rust-lang/cargo#3604 [RFC 1623]: https://github.com/rust-lang/rfcs/blob/master/text/1623-static.md

It looks like the `OutputType::Metadata` kind in the compiler was misclassified in rust-lang#38571 long ago by accident as incompatible with codegen units and a single output file. This means that if you emit both a linkable artifact and metadata it silently turns off multiple codegen units unintentionally! This commit corrects the situation to ensure that if `--emit metadata` is used it doesn't implicitly disable multiple codegen units. This will ensure we don't accidentally regress compiler performance when striving to implement pipelined compilation!

…oli-obk rustc: Flag metadata compatible with multiple CGUs It looks like the `OutputType::Metadata` kind in the compiler was misclassified in rust-lang#38571 long ago by accident as incompatible with codegen units and a single output file. This means that if you emit both a linkable artifact and metadata it silently turns off multiple codegen units unintentionally! This commit corrects the situation to ensure that if `--emit metadata` is used it doesn't implicitly disable multiple codegen units. This will ensure we don't accidentally regress compiler performance when striving to implement pipelined compilation!

rust-highfive assigned nikomatsakis Dec 23, 2016

nrc force-pushed the emit-metadata-change branch from be65826 to 8ee4860 Compare December 23, 2016 07:27

nrc unassigned nikomatsakis Dec 23, 2016

rust-highfive assigned alexcrichton Dec 27, 2016

nrc force-pushed the emit-metadata-change branch from 28decd4 to bc4b42f Compare December 28, 2016 01:21

alexcrichton mentioned this pull request Dec 28, 2016

Tracking issue for reverting cargo check in Rust 1.15 #38666

Closed

2 tasks

alexcrichton reviewed Dec 28, 2016

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nrc added 3 commits December 29, 2016 13:24

Change --crate-type metadata to --emit=metadata

7720cf0

Add a test for rust-lang#38273

71f161c

Closes 38273

Restore --crate-type=metadata as an alias for --crate-type=rlib,--emi…

9c89166

…t=metadata + a warning

nrc mentioned this pull request Dec 29, 2016

Extraneous warnings about dead code rust-lang/rls#116

Closed

Support --emit=foo,metadata

b059a80

nrc force-pushed the emit-metadata-change branch from bc4b42f to b059a80 Compare December 29, 2016 05:17

nrc added a commit to nrc/cargo that referenced this pull request Dec 29, 2016

Use --emit=metadata rather than --crate-type=metadata

43af12a

Requires rust-lang/rust#38571

nrc mentioned this pull request Dec 29, 2016

cargo check: use --emit=metadata rather than --crate-type=metadata rust-lang/cargo#3468

Merged

bors added a commit that referenced this pull request Dec 29, 2016

Auto merge of #38571 - nrc:emit-metadata-change, r=alexcrichton

e571f2d

Change --crate-type metadata to --emit=metadata WIP

bors merged commit b059a80 into rust-lang:master Dec 29, 2016

bors added a commit to rust-lang/cargo that referenced this pull request Jan 3, 2017

Auto merge of #3468 - nrc:metadata-emit, r=alexcrichton

9d19975

cargo check: use --emit=metadata rather than --crate-type=metadata Requires rust-lang/rust#38571 (don't land before that does) r? @alexcrichton

nrc added a commit to nrc/cargo that referenced this pull request Jan 4, 2017

Use --emit=metadata rather than --crate-type=metadata

655decc

Requires rust-lang/rust#38571

bors added a commit to rust-lang/cargo that referenced this pull request Jan 5, 2017

Auto merge of #3468 - nrc:metadata-emit, r=alexcrichton

154a30b

cargo check: use --emit=metadata rather than --crate-type=metadata Requires rust-lang/rust#38571 (don't land before that does) r? @alexcrichton

alexcrichton mentioned this pull request Apr 25, 2019

rustc: Flag metadata compatible with multiple CGUs #60270

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Change --crate-type metadata to --emit=metadata #38571

Change --crate-type metadata to --emit=metadata #38571

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Change --crate-type metadata to --emit=metadata #38571

Change --crate-type metadata to --emit=metadata #38571

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