linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO #103092

petrochenkov · 2022-10-15T18:10:28Z

In #100404 this logic was originally disabled for MSVC due to issues with LTO, but the same issues appear on windows-gnu with LLD because that LLD uses the same underlying logic as MSVC LLD, just with re-syntaxed command line options.

So this PR just disables it for LTO builds in general.

… + LTO

rust-highfive · 2022-10-15T18:10:31Z

r? @lcnr

(rust-highfive has picked a reviewer for you, use r? to override)

petrochenkov · 2022-10-15T18:11:34Z

@belovdv you originally suggested this alternative, and you were right, this solution is probably the least bad.

bjorn3 · 2022-10-16T12:12:42Z

compiler/rustc_codegen_ssa/src/base.rs

+        // If global LTO is enabled then almost everything (*) is glued into a single object file,
+        // so this logic is not necessary and can cause issues on some targets (due to weak lang
+        // item symbols being "privatized" to that object file), so we disable it.
+        // (*) Native libs, and `#[compiler_builtins]` and `#[no_builtins]` crates are not glued,


#![no_builtins] is stable. Lang items are not, so that is probably not an issue.

luqmana · 2022-10-17T03:10:31Z

Sweet, I think this should also fix the issue I've been seeing on illumos lately with LTO.

e.g. trying to build bat:

error: linking with `gcc` failed: exit status: 1                                                                                                                                                         
  |                                                                                                                                                                                                      
  = note: "gcc" "-m64" "-std=c99" "/tmp/rustcsVN1FO/symbols.o" "/tmp/bat/target/release/deps/bat-e4fceccbe6e2b327.bat.7aa865dd-cgu.0.rcgu.o" "-Wl,-z,ignore" "-L" "/tmp/bat/targe
t/release/deps" "-L" "/tmp/bat/target/release/build/libgit2-sys-b78d3b7d704ff41e/out/build" "-L" "/usr/lib/amd64" "-L" "/tmp/bat/target/release/build/onig_sys-159ec9d31ec0a92a/o
ut" "-L" "/home/luqman/.rustup/toolchains/nightly-x86_64-unknown-illumos/lib/rustlib/x86_64-unknown-illumos/lib" "-Wl,-Bstatic" "/tmp/rustcsVN1FO/liblibgit2_sys-e95cd72243699990.rlib" "/tmp/rustcsVN1FO
/libonig_sys-8c63ac69bc862d8b.rlib" "/home/luqman/.rustup/toolchains/nightly-x86_64-unknown-illumos/lib/rustlib/x86_64-unknown-illumos/lib/libcompiler_builtins-5843a5198c157050.rlib" "-Wl,-Bdynamic" "-
lkstat" "-lz" "-lsendfile" "-llgrp" "-lsocket" "-lposix4" "-lpthread" "-lresolv" "-lnsl" "-lumem" "-lgcc_s" "-lm" "-lrt" "-lpthread" "-lsendfile" "-llgrp" "-lc" "-lssp" "-L" "/home/luqman/.rustup/toolc
hains/nightly-x86_64-unknown-illumos/lib/rustlib/x86_64-unknown-illumos/lib" "-o" "/tmp/bat/target/release/deps/bat-e4fceccbe6e2b327" "-nodefaultlibs"                                       
  = note: Undefined                     first referenced                                                                                                                                                 
           symbol                           in file                                                                                                                                                      
          rust_begin_unwind                   /tmp/rustcsVN1FO/symbols.o                                                                                                                                 
          rust_oom                            /tmp/rustcsVN1FO/symbols.o                                                                                                                                 
          ld: fatal: symbol referencing errors. No output written to /tmp/bat/target/release/deps/bat-e4fceccbe6e2b327                                                                       
          collect2: error: ld returned 1 exit status                                                                                                                                                     
                                                                                                                                                                                                         
                                                                                                                                                                                                         
error: could not compile `bat` due to previous error

lcnr · 2022-10-17T08:14:07Z

r? compiler

lcnr · 2022-10-17T08:14:46Z

they are on vacation rn

r? compiler

wesleywiser · 2022-10-18T14:56:26Z

@bors r+

bors · 2022-10-18T14:56:28Z

📌 Commit acf51e1 has been approved by wesleywiser

It is now in the queue for this repository.

petrochenkov · 2022-10-19T11:15:58Z

Beta-nominating as a regression fix (the regression has also first landed on beta).

wesleywiser · 2022-10-20T14:14:54Z

@bors p=1

Fixes beta regression and we'd like to see this land on nightly before it's backported

apiraino · 2022-10-20T14:15:56Z

Beta backport accepted as per compiler team on Zulip

@rustbot label +beta-accepted

bors · 2022-10-20T16:20:54Z

⌛ Testing commit acf51e1 with merge 5ffa67d...

bors · 2022-10-20T19:39:09Z

☀️ Test successful - checks-actions
Approved by: wesleywiser
Pushing 5ffa67d to master...

rust-timer · 2022-10-20T21:02:29Z

Finished benchmarking commit (5ffa67d): 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.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.1%	[2.1%, 2.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

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

the arithmetic mean of the percent change ↩
number of relevant changes ↩

[beta] backports - Use rebind instead of dummy binder in `SameTypeModuloInfer` relation rust-lang#102059 - Add missing space between notable trait tooltip and where clause rust-lang#102107 - Avoid repeated re-initialization of the BufReader buffer rust-lang#102760 - Ensure enum cast moves rust-lang#103016 - Fix `TyKind::is_simple_path` rust-lang#103176 - Do anonymous lifetimes remapping correctly for nested rpits rust-lang#103205 - [beta] Cargo backport 1.65.0 rust-lang#103303 - linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO rust-lang#103092 r? `@ghost`

linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO In rust-lang#100404 this logic was originally disabled for MSVC due to issues with LTO, but the same issues appear on windows-gnu with LLD because that LLD uses the same underlying logic as MSVC LLD, just with re-syntaxed command line options. So this PR just disables it for LTO builds in general.

linker: Fix weak lang item linking with combination windows-gnu + LLD…

acf51e1

… + LTO

rust-highfive assigned lcnr Oct 15, 2022

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Oct 15, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 15, 2022

bjorn3 reviewed Oct 16, 2022

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rust-highfive assigned fee1-dead and unassigned lcnr Oct 17, 2022

rust-highfive assigned wesleywiser and unassigned fee1-dead Oct 17, 2022

wesleywiser approved these changes Oct 18, 2022

View reviewed changes

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 18, 2022

petrochenkov mentioned this pull request Oct 19, 2022

Missing rust_begin_unwind symbol for msp430 (debug-only?) builds #102290

Closed

petrochenkov added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Oct 19, 2022

rustbot added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Oct 20, 2022

bors added the merged-by-bors This PR was explicitly merged by bors. label Oct 20, 2022

bors merged commit 5ffa67d into rust-lang:master Oct 20, 2022

rustbot added this to the 1.66.0 milestone Oct 20, 2022

cuviper mentioned this pull request Oct 20, 2022

[beta] backports #103316

Merged

cuviper modified the milestones: 1.66.0, 1.65.0 Oct 20, 2022

cuviper removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Oct 20, 2022

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linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO #103092

linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO #103092

petrochenkov commented Oct 15, 2022 •

edited

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rust-highfive commented Oct 15, 2022

petrochenkov commented Oct 15, 2022

bjorn3 Oct 16, 2022

luqmana commented Oct 17, 2022

lcnr commented Oct 17, 2022

lcnr commented Oct 17, 2022 •

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wesleywiser commented Oct 18, 2022

bors commented Oct 18, 2022

petrochenkov commented Oct 19, 2022

wesleywiser commented Oct 20, 2022

apiraino commented Oct 20, 2022

bors commented Oct 20, 2022

bors commented Oct 20, 2022

rust-timer commented Oct 20, 2022

linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO #103092

linker: Fix weak lang item linking with combination windows-gnu + LLD + LTO #103092

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petrochenkov commented Oct 15, 2022 • edited Loading

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lcnr commented Oct 17, 2022 • edited Loading

wesleywiser commented Oct 18, 2022

bors commented Oct 18, 2022

petrochenkov commented Oct 19, 2022

wesleywiser commented Oct 20, 2022

apiraino commented Oct 20, 2022

bors commented Oct 20, 2022

bors commented Oct 20, 2022

rust-timer commented Oct 20, 2022

Overall result: no relevant changes - no action needed

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petrochenkov commented Oct 15, 2022 •

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lcnr commented Oct 17, 2022 •

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