Start using serde_derive in a couple places in the compiler

[Zoxc]

This is #56447 with the build changes in #56462

r? @alexcrichton

[alexcrichton]

@bors: r+

Once this is green on Travis feel free to p=1 since this is blocking other work

[bors]

📌 Commit 7bd36fb has been approved by alexcrichton

[Zoxc]

@bors r=alexcrichton

[Zoxc]

@bors p=1

[Zoxc]

I've changed the approach here to something that requires no build system changes. I made #[no_link] cause extern crate to no longer be reexported, so using a crate won't also require the proc macro used to build it. I should also check for pub extern crate and #[no_link], since that combination is an error. I think that doing this is a breaking change though, so I should probably make a new unstable attribute for this.

I also added a serde_derive dependency to rustc_codegen_llvm so we won't get errors building the stage1 compiler.

[alexcrichton]

To understand why this is a breaking change, is #[no_link] synthesized by the compiler on dependencies to procedural macros? Or is it a stable attribute we're worried about breaking?

FWIW I think it's worthwhile to get this working without a special attribute because we'll ideally want to pull in crates.io crates that have their own procedural macros, and we wouldn't necessarily want them to annotate imports.

Also I'm not sure I quite understand why rustc_codegen_llvm changes are needed, is it just to prove it out or to fix a bug?

FWIW though I do agree that not requiring procedural macros when depending on a crate is the behavior we want!

[Zoxc]

#[no_link] is already stable, and I think it's used to use a crate while not linking to any code. I don't think it does anything when applied to proc macros, but it can certainly appear on stable code importing proc macro crates. I'm co-opting it here to also mean no metadata linking to the crate, so it won't be needed when dependencies builds against the current crate.

In the general case for crates.io we need to build proc macros twice when cross compiling libraries which also export the macros / crates (which is the default currently). We need to build them once for the host and then again for the target. We also need to change the built libraries to refer to the target proc macros instead of the host proc macros used to compile them.

The rustc_codegen_llvm changes is needed because the bootstrap compiler doesn't have the #[no_link] change, so it requires serde_derive around. That won't cause problems for cross-compilation though as that only applies to later stages.

[Zoxc]

I'll have to change the approach taken to enabled proc macros in rustc. Consider this blocked on #57626 for now

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:34100700:start=1548689157290046396,finish=1548689160027264021,duration=2737217625
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
Setting environment variables from .travis.yml
$ export IMAGE=x86_64-gnu-llvm-6.0
---
[00:01:36] 
######################################################################## 100.0%
[00:01:36] extracting /checkout/obj/build/cache/2019-01-18/cargo-beta-x86_64-unknown-linux-gnu.tar.gz
[00:01:37]     Updating crates.io index
[00:01:47] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:47] Build completed unsuccessfully in 0:00:23
[00:01:47] make: *** [prepare] Error 1
[00:01:47] Makefile:70: recipe for target 'prepare' failed
[00:01:48] Command failed. Attempt 2/5:
[00:01:48] Command failed. Attempt 2/5:
[00:01:48] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:48] Build completed unsuccessfully in 0:00:00
[00:01:48] make: *** [prepare] Error 1
[00:01:48] Makefile:70: recipe for target 'prepare' failed
[00:01:50] Command failed. Attempt 3/5:
[00:01:50] Command failed. Attempt 3/5:
[00:01:51] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:51] Build completed unsuccessfully in 0:00:00
[00:01:51] Makefile:70: recipe for target 'prepare' failed
[00:01:51] make: *** [prepare] Error 1
[00:01:54] Command failed. Attempt 4/5:
[00:01:54] Command failed. Attempt 4/5:
[00:01:54] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:54] Build completed unsuccessfully in 0:00:00
[00:01:54] make: *** [prepare] Error 1
[00:01:54] Makefile:70: recipe for target 'prepare' failed
[00:01:58] Command failed. Attempt 5/5:
[00:01:58] Command failed. Attempt 5/5:
[00:01:58] error: the lock file /checkout/Cargo.lock needs to be updated but --locked was passed to prevent this
[00:01:58] Build completed unsuccessfully in 0:00:00
[00:01:58] Makefile:70: recipe for target 'prepare' failed
[00:01:58] make: *** [prepare] Error 1
[00:01:58] The command has failed after 5 attempts.
---
travis_time:end:117b5e44:start=1548689292583454401,finish=1548689292588397507,duration=4943106
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:0ed9e820
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:085d6508
travis_time:start:085d6508
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:04464afd
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:152e9680:start=1548691347493915922,finish=1548691349962113442,duration=2468197520
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
Setting environment variables from .travis.yml
$ export IMAGE=x86_64-gnu-llvm-6.0
---

[00:08:16] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:08:16] tidy error: /checkout/src/librustc_metadata/creader.rs:371: tab character
[00:08:16] tidy error: /checkout/src/librustc_metadata/creader.rs:371: trailing whitespace
[00:08:18] some tidy checks failed
[00:08:18] 
[00:08:18] 
[00:08:18] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor" "--quiet"
[00:08:18] 
[00:08:18] 
[00:08:18] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:08:18] Build completed unsuccessfully in 0:00:50
[00:08:18] Build completed unsuccessfully in 0:00:50
[00:08:18] make: *** [tidy] Error 1
[00:08:18] Makefile:68: recipe for target 'tidy' failed
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:1887fce5
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Mon Jan 28 16:11:01 UTC 2019
---
travis_time:end:0fd38408:start=1548691861993747489,finish=1548691861998381449,duration=4633960
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:09fd9b99
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:106d7370
travis_time:start:106d7370
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:159f27b8
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:106e5dd0:start=1548713318013727339,finish=1548713321167929911,duration=3154202572
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
Setting environment variables from .travis.yml
$ export IMAGE=x86_64-gnu-llvm-6.0
---
[00:06:12]    Compiling rustc_data_structures v0.0.0 (/checkout/src/librustc_data_structures)
[00:06:12]    Compiling rustc_apfloat v0.0.0 (/checkout/src/librustc_apfloat)
[00:06:15]    Compiling arena v0.0.0 (/checkout/src/libarena)
[00:06:15]    Compiling syntax_pos v0.0.0 (/checkout/src/libsyntax_pos)
[00:06:15] error: internal compiler error: src/librustc/middle/stability.rs:751: encountered unmarked API: DefId(49/1:9 ~ serde_derive[774e]::Serialize[0])
[00:06:15]    |
[00:06:15]    |
[00:06:15] 40 | use serde::{Serialize, Deserialize};
[00:06:15] 
[00:06:15] thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:526:9
[00:06:15] note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
[00:06:15] error: aborting due to previous error
---
[00:06:15] note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
[00:06:15] 
[00:06:15] note: rustc 1.33.0-beta.1 (d1add9723 2019-01-17) running on x86_64-unknown-linux-gnu
[00:06:15] 
[00:06:15] note: compiler flags: -Z force-unstable-if-unmarked -C prefer-dynamic -C opt-level=2 -C prefer-dynamic -C debug-assertions=y -C link-args=-Wl,-rpath,$ORIGIN/../lib --crate-type dylib
[00:06:15] note: some of the compiler flags provided by cargo are hidden
[00:06:15] 
[00:06:15] error: Could not compile `syntax_pos`.
[00:06:15] warning: build failed, waiting for other jobs to finish...

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[bors]

☔ The latest upstream changes (presumably #57948) made this pull request unmergeable. Please resolve the merge conflicts.