Support x test --stage 1 ui-fulldeps

[jyn514]

@Nilstrieb had an excellent idea the other day: the same way that rustdoc is able to load rustc_driver from the sysroot, ui-fulldeps tests should also be able to load it from the sysroot. That allows us to run fulldeps tests with stage1, without having to fully rebuild the compiler twice. It does unfortunately have the downside that we're building the tests with the bootstrap compiler, not the in-tree sources, but since most of the fulldeps tests are for the API of the compiler, that seems ok.

I think it's possible to extend this to run-make-fulldeps, but I've run out of energy for tonight.

• Move plugin tests into a subdirectory.

  Plugins are loaded at runtime with dlopen and so require the ABI of the running compile to match the ABI of the compiler linked with rustc_driver. As a result they can't be supported in stage 1 and have to use // ignore-stage1.

• Remove ignore-stage1 from most non-plugin tests

• Ignore diagnostic tests in stage 1. Even though this requires a stage 2 build to load rustc_driver, it's primarily testing the error message that the running compiler emits when the diagnostic struct is malformed.

• Pass -Zforce-unstable-if-unmarked in stage1, not just stage2. That allows running hash-stable-is-unstable in stage1, since it now suggests adding rustc_private to enable loading the crates.

• Add libLLVM.so to the stage0 target sysroot, to allow fulldeps tests that act as custom drivers to load it at runtime.

• Pass --sysroot stage0-sysroot in compiletest so that we use the correct version of std.

• Move a few lint tests from ui-fulldeps to ui

  These had an aux-build:lint-group-plugin-test.rs that they never actually loaded with feature(plugin) nor tested. I removed the unused aux-build and they pass fine with stage 1.

Fixes #75905.

[rustbot]

r? @albertlarsan68

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[albertlarsan68]

@bors r+ rollup=iffy
Is stage1 tested in CI?

[bors]

📌 Commit d6af602 has been approved by albertlarsan68

It is now in the queue for this repository.

[bors]

⌛ Testing commit d6af602 with merge ba5dc55d0ba22c4faa5db8648961e53261aed43a...

[bors]

💔 Test failed - checks-actions

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A job failed! Check out the build log: (web) (plain)

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[albertlarsan68]

@bors retry seems supurious

curl: (6) Could not resolve host: ci-mirrors.rust-lang.org

[bors]

⌛ Testing commit d6af602 with merge de96f3d...

[jyn514]

Is stage1 tested in CI?

Yes, since recently :) see src/ci/docker/host-x86_64/x86_64-gnu-llvm-14-stage1/.

[bors]

☀️ Test successful - checks-actions
Approved by: albertlarsan68
Pushing de96f3d to master...

[bors]

☀️ Test successful - checks-actions
Approved by: albertlarsan68
Pushing de96f3d to master...

[rust-timer]

Finished benchmarking commit (de96f3d): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	7.4%	[7.4%, 7.4%]	1
Regressions ❌ (secondary)	1.7%	[1.7%, 1.7%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.4%	[-3.4%, -3.4%]	1
All ❌✅ (primary)	7.4%	[7.4%, 7.4%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	6.0%	[3.6%, 10.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0