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

View reviewed changes

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

petrochenkov deleted the weaklto branch February 22, 2025 18:30

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