show linker output even if the linker succeeds

[jyn514]

• show stderr by default
• show stdout if --verbose is passed
• remove both from RUSTC_LOG
• hide the linker cli args unless --verbose is passed

fixes #83436. fixes #38206. fixes #109979. helps with #46998. cc https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/uplift.20some.20-Zverbose.20calls.20and.20rename.20to.E2.80.A6.20compiler-team.23706/near/408986134

try-job: aarch64-apple

r? @bjorn3

[rustbot]

rustc_macros::diagnostics was changed

cc @davidtwco, @compiler-errors, @TaKO8Ki

[jyn514]

hmm actually this is a slight expansion of scope but @bjorn3 how would you feel about not printing the giant list of linker arguments unless someone passes --verbose (#109979)

[jyn514]

also i know we settled on not showing stdout by default but it's useful for debugging search paths - maybe we should show it after all? it seems silly to have to pass both -Wl,--verbose and --verbose. #46998 (comment)

[bors]

☔ The latest upstream changes (presumably #119662) made this pull request unmergeable. Please resolve the merge conflicts.

[jyn514]

hmm. that test has the following comment:

rust/tests/incremental/commandline-args.rs

Lines 13 to 20 in e9a009f

	// Between revisions 1 and 2, we are changing the debuginfo-level, which should
	// invalidate the cache. Between revisions 2 and 3, we are adding `--verbose`
	// which should have no effect on the cache. Between revisions, we are adding
	// `--remap-path-prefix` which should invalidate the cache:
	//[rpass1] compile-flags: -C debuginfo=0
	//[rpass2] compile-flags: -C debuginfo=2
	//[rpass3] compile-flags: -C debuginfo=2 --verbose
	//[rpass4] compile-flags: -C debuginfo=2 --verbose --remap-path-prefix=/home/bors/rust=src

i suppose those lines are all invalid now, it should be testing that the CGU is not reused? i'm not sure why it's testing --verbose specifically, maybe it's enough to test any untracked CLI arg. i'll change it to --diagnostic-width.

i'm realizing your comments are all about #119129. i feel slightly uncomfortable making unrelated changes in this PR ... how do you feel about splitting them into a separate PR so i can assign michaelwoerister?

[bjorn3]

how do you feel about splitting them into a separate PR so i can assign michaelwoerister?

Sure

[bjorn3]

hide the linker cli args unless --verbose is passed

I prefer not doing this. It is helpful whenever a linkage issue is opened to not have to ask to rerun with RUSTFLAGS="--verbose". If you revert this change r=me. If you still want to keep it, let me thing about it for a bit.

[bors]

💔 Test failed - checks-actions

[jyn514]

ok, the current problem is that rustc_codegen_gcc ignores RUSTFLAGS=-Alinker-messages, which results in this error:

 error: linker stderr: /usr/bin/ld: /checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/cg_gcc/mini_core.mini_core.e55951eb20a0121d-cgu.0.rcgu.o: relocation in read-only section `.rodata.global.c'
       /usr/bin/ld: creating DT_TEXTREL in a shared object

@antoyo how do you prefer i fix this? i can either:

• change y.sh test to respect RUSTFLAGS, which may have other effects on your test suite
• change y.sh test to unconditionally pass -Alinker-warnings
• try and figure out how to fix the linker warning. i would appreciate your help with this.

[jyn514]

actually wait what, where is -D warnings coming from

i don't see that in the flags y.sh passes to rustc

[antoyo]

@jyn514: You can pass the flags through CG_RUSTFLAGS.

[jyn514]

@rustbot ready

note that this is based off of #133633 so you may want to review that first.

[bors]

☔ The latest upstream changes (presumably #134052) made this pull request unmergeable. Please resolve the merge conflicts.