fix issue 54153 by not testing issue-18804 on Windows nor OS X.

[pnkfelix]

Fix #54153

[rust-highfive]

r? @alexcrichton

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[nikic]

It's not entirely obvious to me why this test requires optimization.

[pnkfelix]

its not obvious to me either; the requirement may only manifest itself on "OS X" ...

which would lead one to wonder if instead I should tag this test with an // ignore-macos, and then file an additional test just of "OS X" that has the -O flag required?

(Note also that #[linkage] is notorious for being platform-dependent and also has a number of supposed latent bugs...)

In any case I am non-plussed that I cannot do optimize-tests = false in my config.toml without running into this.

[pnkfelix]

cc #18804

[nikic]

On Ubuntu, at least a manual run seems to work fine. I did:

rustc +nightly -C opt-level=0 lib.rs
rustc +nightly --extern lib=liblib.rlib -C opt-level=0 test.rs
./test

Not sure how well that corresponds to whatever run-pass does.

[nikic]

After checking IR, with optimizations the extern_weak global is just optimized away, so it's not actually testing anything. Looking at src/test/run-pass/linkage1.rs, which is another test that uses extern_weak, it skips windows and macos, so I'm assuming those just don't support this linkage.

So I think the right way to fix this is to a) add ignore-windows and ignore-macos as they have no extern_weak linkage and b) add -C no-prepopulate-passes so this test actually tests something.

[alexcrichton]

Ah yeah I agree with @nikic, this test should be ignored on macos/windows because the extern_weak linkage doesn't really exist there

[pnkfelix]

Okay I'll revise the PR.

[nikic]

@bors r+ rollup

[bors]

📌 Commit 42167b9 has been approved by nikic

[nikic]

@bors r-

Failed in rollup #56817 with ... an LLVM assertion failure :(

[01:00:08] ---- [run-pass] run-pass/issues/issue-18804/main.rs stdout ----
[01:00:08] 
[01:00:08] error: test compilation failed although it shouldn't!
[01:00:08] status: signal: 6
[01:00:08] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/run-pass/issues/issue-18804/main.rs" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/issues/issue-18804/main/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-C" "no-prepopulate-passes" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/issues/issue-18804/main/auxiliary"
[01:00:08] ------------------------------------------
[01:00:08] 
[01:00:08] ------------------------------------------
[01:00:08] stderr:
[01:00:08] stderr:
[01:00:08] ------------------------------------------
[01:00:08] rustc: /checkout/src/llvm/include/llvm/ADT/StringRef.h:239: char llvm::StringRef::operator[](size_t) const: Assertion `Index < Length && "Invalid index!"' failed.
[01:00:08] ------------------------------------------
[01:00:08] 
[01:00:08] thread '[run-pass] run-pass/issues/issue-18804/main.rs' panicked at 'explicit panic', src/tools/compiletest/src/runtest.rs:3252:9
[01:00:08] note: Run with `RUST_BACKTRACE=1` for a backtrace.

[nikic]

Just checked this locally with an assertion-enabled build ... the issue is that due to -C no-prepopulate-passes the name-anon-globals pass is not run, but we have anon globals and are using ThinLTO buffers. We have checks in place to emit a compile error in this case (rather than this wonderful LLVM assertion), but they happen to miss this particular case.

To fix this you can either drop the -C no-prepopulate-passes or add an additional -C passes=name-anon-globals (we do this in a few other tests).

We should probably start always running name-anon-globals (even under no-prepopulate-passes), as this issue has come up a few times now and we never quite seem to catch all the cases where it's necessary to run it.

[pnkfelix]

@bors r=nikic

[bors]

📌 Commit 933efd7 has been approved by nikic

[pnkfelix]

@bors rollup