tests: extend remap-path-prefix-std to all stdlib rlibs by paradoxicalguy · Pull Request #156570 · rust-lang/rust

paradoxicalguy · 2026-05-14T11:31:51Z

problem:

the current remap-path-prefix-std run-make test validates path remapping for libstd.rlib, which leaves the rest of the distributed stdlib artifacts unchecked.

fix:

generalizing the test to go over over all distributed .rlib files found in the target sysroot libdir instead of checking only the libstd.

result:

improves reproducibility coverage for distributed stdlib artifacts.

r? @Urgau

Urgau · 2026-05-14T13:49:34Z

@bors try jobs=dist-x86_64-linux

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-x86_64-linux

rust-bors · 2026-05-14T16:59:37Z

☀️ Try build successful (CI)
Build commit: 8d33ecc (8d33ecc7330a13730e8a40214401163109712e5d, parent: 1a70f8d36e818b45829a5c065fd6004c9047e8d1)

Urgau · 2026-05-14T19:08:38Z

@bors r+ rollup

rust-bors · 2026-05-14T19:08:41Z

📌 Commit 6a3fc8b has been approved by Urgau

It is now in the queue for this repository.

@Urgau

…lean, r=Urgau tests: extend remap-path-prefix-std to all stdlib rlibs ### problem: the current `remap-path-prefix-std` run-make test validates path remapping for `libstd.rlib`, which leaves the rest of the distributed `stdlib` artifacts unchecked. ### fix: generalizing the test to go over over all distributed `.rlib` files found in the target `sysroot libdir` instead of checking only the `libstd`. ### result: improves reproducibility coverage for distributed `stdlib` artifacts. r? @Urgau

…uwer Rollup of 4 pull requests Successful merges: - #156452 (Implement pinned drop sugar) - #156571 (Disable `main_needs_argc_argv` for Wasm) - #156565 (delegation: emit error when self type is not specified and accessed) - #156570 (tests: extend remap-path-prefix-std to all stdlib rlibs)

JonathanBrouwer · 2026-05-15T06:33:49Z

@bors r-
#156584 (comment)

rust-bors · 2026-05-15T06:33:55Z

This pull request was unapproved.

This PR was contained in a rollup (#156584), which was unapproved.

View changes since this unapproval

Urgau · 2026-05-15T10:04:22Z

Let's do a quick try run to be sure.

@bors try jobs=dist-i586-gnu-i586-i686-musl

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

rust-bors · 2026-05-15T11:34:06Z

💔 Test for e47907c failed: CI. Failed job:

try - dist-i586-gnu-i586-i686-musl (web logs, enhanced plaintext logs)

tests: extend remap-path-prefix-std to all stdlib rlibs

rust-bors · 2026-07-15T19:04:52Z

✌️ @paradoxicalguy, you can now perform try builds on this pull request!

Warning

You used the legacy format of the delegate command.
The new format is @bors delegate[=<username>] [<try|review>].

You can now post @bors try to start a try build.

paradoxicalguy · 2026-07-15T19:06:14Z

yay thank you!

rust-bors · 2026-07-15T21:17:31Z

☀️ Try build successful (CI)
Build commit: c4ab863 (c4ab863e358eb59a031d1e2fcc6ef12157ca0eae)
Base parent: 2118366 (2118366bbfe2e57ec0e8417ea270833e9f013640)

paradoxicalguy · 2026-07-15T21:19:26Z

@bors try jobs=dist-i586-gnu-i586-i686-musl

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

rust-bors · 2026-07-15T22:47:35Z

💔 Test for 6b1fa23 failed: CI. Failed job:

try - dist-i586-gnu-i586-i686-musl (web logs, enhanced plaintext logs)

rustbot · 2026-07-16T09:11:57Z

⚠️ Warning ⚠️

This PR is based on an upstream commit that is older than 28 days.

It's recommended to update your branch according to the rustc-dev-guide.

paradoxicalguy · 2026-07-16T09:12:12Z

@bors try jobs=dist-i586-gnu-i586-i686-musl

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

rust-bors · 2026-07-16T10:42:03Z

💔 Test for b3b0fe2 failed: CI. Failed job:

try - dist-i586-gnu-i586-i686-musl (web logs, enhanced plaintext logs)

…king properly via prior test

rustbot · 2026-07-17T08:04:42Z

compiler-builtins is developed in its own repository. If possible, consider making this change to rust-lang/compiler-builtins instead.

cc @tgross35

paradoxicalguy · 2026-07-17T08:05:23Z

@bors try jobs=dist-i586-gnu-i586-i686-musl

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

rust-bors · 2026-07-17T09:46:05Z

☀️ Try build successful (CI)
Build commit: 32d8583 (32d8583df382b763630da17b83d38ed4532a3f94)
Base parent: 4a9d536 (4a9d5368df6450bbd2fc8dde4508c3e5d83bb19d)

paradoxicalguy · 2026-07-17T10:05:02Z

FINALLY 🎉
tho can we get a final code review for both files? if they are good to go, i'll open the compiler-builtins PR first.

@Urgau @tgross35

Urgau · 2026-07-18T09:41:55Z

+        let commit_hash = debuginfo_map
+            .split('\t')
+            .next()
+            .and_then(|first| first.split("/rustc/").nth(1))
+            .and_then(|s| s.split('/').next())
+            .map(String::from);


Why do we do this extraction? Looking at #t-compiler > Checking reproducibility of rustc @ 💬 I feel like we could just apply all remapping like we do for llvm, no?

rust/compiler/rustc_llvm/build.rs

Lines 276 to 283 in b26c8ef

// Remap ci-llvm include paths in debug info for reproducible builds.

if let Some(maps) = tracked_env_var_os("RUSTC_DEBUGINFO_MAP")

&& let Some(maps_str) = maps.to_str()

{

for map in maps_str.split('\t') {

cfg.flag_if_supported(&format!("-ffile-prefix-map={map}"));

}

}

View changes since the review

wait i'll test this one rn, thanks

tested this: switched to -ffile-prefix-map, looping over all RUSTC_DEBUGINFO_MAP entries like rustc_llvm's build.rs does.
added one extra mapping for the crate's own manifest dir since it's not covered by the existing entries.
removed the old line-538 mapping since it was conflicting with this.
verified via llvm-dwarfdump: all comp_dir entries now show /rustc/<hash>, no leaked paths.

I'm surprised the crate own manifest dir is still necessary, but oh well, if it works.

Ping me when you push.

mb it doesnt need a strict manifest dir
removing it gives: DW_AT_comp_dir ("/rustc/08f62523b1c3262cc2f0288a3369b760ab4bda45/library/compiler-builtins/compiler-builtins").
instead of the shorter DW_AT_comp_dir ("/rustc/08f62523b1c3262cc2f0288a3369b760ab4bda45").
no path leak tho. happy to keep code or drop it

Well, the first DW_AT_comp_dir is more inline with what I would expect, to be honest. I would say, let's drop it, that makes the code simpler and clearer.

sure, i'll open a separate pr first

paradoxicalguy · 2026-07-19T19:48:45Z

why bootstrap doesn't just thread this through CFLAGS/CXXFLAGS instead of the custom RUSTC_DEBUGINFO_MAP env var. does the same cargo#4423 forwarding issue apply to CFLAGS/CXXFLAGS too, or is there another reason bootstrap doesn't use them here?

Urgau · 2026-07-19T20:21:56Z

That's a very good point, I didn't think of that. Turns out we already even have such remapping flags set in

rust/src/bootstrap/src/lib.rs

Lines 1323 to 1332 in 9f36de7

    
           if let Some(map_to) = self.debuginfo_map_to(which, RemapScheme::NonCompiler) { 
        
               let map = format!("{}={}", self.src.display(), map_to); 
        
               let cc = self.cc(target); 
        
               if cc.ends_with("clang") || cc.ends_with("gcc") { 
        
                   base.push(format!("-fdebug-prefix-map={map}")); 
        
               } else if cc.ends_with("clang-cl.exe") { 
        
                   base.push("-Xclang".into()); 
        
                   base.push(format!("-fdebug-prefix-map={map}")); 
        
               } 
        
           }

rust/src/bootstrap/src/core/builder/cargo.rs

Line 433 in 9f36de7

let env = format!("CFLAGS_{triple_underscored}");

I wonder why it's not working then, could it be because we only set it for the target?

paradoxicalguy · 2026-07-20T07:50:23Z

mark was asking here
rust-lang/compiler-builtins#1236 (comment) .

and found it, cc_unhandled_cflags only pushes -fdebug-prefix-map if cc.ends_with("clang") || cc.ends_with("gcc"). my CC resolves to plain "cc" (common symlink), which doesn't match either suffix, so the flag never gets added.
not a target-scoping issue looks like a gap in that string check.

paradoxicalguy · 2026-07-20T22:46:40Z

i tried it with

if cc.ends_with("clang")
                || cc.ends_with("gcc")
                || cc.file_name().is_some_and(|f| f == "cc")
            {
                base.push(format!("-fdebug-prefix-map={map}"));
           }

while reverting the compiler-builtins as it was (only build.flag_if_supported(&format!("-ffile-prefix-map={}=.", root.display()));)

final result gives:
/rustc/08f62523b1c3262cc2f0288a3369b760ab4bda45/library/compiler-builtins/compiler-builtins

the remap-path-prefix-std run-make test also passes with just the bootstrap change locally.

rustbot added A-run-make Area: port run-make Makefiles to rmake.rs S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 14, 2026

rustbot assigned Urgau May 14, 2026

Urgau reviewed May 14, 2026

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Auto merge of #156570 - paradoxicalguy:test-extend-rmake-clean, r=<try>

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tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-x86_64-linux

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JonathanBrouwer mentioned this pull request May 14, 2026

Rollup of 4 pull requests #156584

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Auto merge of #156570 - paradoxicalguy:test-extend-rmake-clean, r=<try>

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tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

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Auto merge of #156570 - paradoxicalguy:test-extend-rmake-clean, r=<try>

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tests: extend remap-path-prefix-std to all stdlib rlibs

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Auto merge of #156570 - paradoxicalguy:test-extend-rmake-clean, r=<try>

6b1fa23

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

use run_unchecked for dwarfdump to avoid unbounded failure output

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Auto merge of #156570 - paradoxicalguy:test-extend-rmake-clean, r=<try>

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tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

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adding compiler-builtin patches, will shift it to a new pr if its wor…

08f6252

…king properly via prior test

rustbot added the A-compiler-builtins Area: compiler-builtins (https://github.com/rust-lang/compiler-builtins) label Jul 17, 2026

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Auto merge of #156570 - paradoxicalguy:test-extend-rmake-clean, r=<try>

32d8583

tests: extend remap-path-prefix-std to all stdlib rlibs try-job: dist-i586-gnu-i586-i686-musl

tgross35 reviewed Jul 17, 2026

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Comment thread library/compiler-builtins/compiler-builtins/build.rs

Urgau reviewed Jul 18, 2026

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paradoxicalguy mentioned this pull request Jul 19, 2026

compiler-builtins: remap RUSTC_DEBUGINFO_MAP paths via -ffile-prefix-map rust-lang/compiler-builtins#1236

Open

	// Remap ci-llvm include paths in debug info for reproducible builds.
	if let Some(maps) = tracked_env_var_os("RUSTC_DEBUGINFO_MAP")
	&& let Some(maps_str) = maps.to_str()
	{
	for map in maps_str.split('\t') {
	cfg.flag_if_supported(&format!("-ffile-prefix-map={map}"));
	}
	}

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