export symbols: support macos/windows(32/64) by cezarbbb · Pull Request #155535 · rust-lang/rust

cezarbbb · 2026-04-20T03:16:28Z

Previously, in the pr #150992 , export symbols only supported Linux. The special prefix and suffix rules for some symbols in macOS and Windows were not fully supported. This pull request attempts to clarify these rules and add corresponding support.

Currently, the undecorate_c_symbol() function has been added to handle macOS _ prefixes, Windows x86 calling convention modifiers (cdecl/stdcall/fastcall/vectorcall), and Arm64EC # prefixes.

*Update: Handling of Windows C++ mangled symbols has now been added(Linux/macOS don't need).

r? @bjorn3 @petrochenkov

rustbot · 2026-04-20T03:16:32Z

r? @wesleywiser

rustbot has assigned @wesleywiser.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

Why was this reviewer chosen?

The reviewer was selected based on:

Owners of files modified in this PR: codegen, compiler
codegen, compiler expanded to 72 candidates
Random selection from 16 candidates

cezarbbb · 2026-04-20T03:20:06Z

Could someone pls give me permission to test whether the current modifications will work correctly on Windows and macOS?
Cause I don't have the corresponding devices.

adwinwhite · 2026-04-20T03:36:02Z

@bors delegate=try

rust-bors · 2026-04-20T03:36:05Z

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

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

cezarbbb · 2026-04-20T03:39:54Z

@bors delegate=try

Thanks!!! It helps me a lot:>

cezarbbb · 2026-04-20T03:40:43Z

@bors try jobs=x86_64-msvc-*

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

rust-bors · 2026-04-20T06:09:18Z

💔 Test for 22e628f failed: CI. Failed job:

try - x86_64-msvc-1 (web logs, enhanced plaintext logs)

cezarbbb · 2026-04-20T06:27:27Z

@bors try jobs=x86_64-msvc-*

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

rust-bors · 2026-04-20T09:06:15Z

💔 Test for 71d836c failed: CI. Failed job:

try - x86_64-msvc-1 (web logs, enhanced plaintext logs)

cezarbbb · 2026-04-20T09:52:11Z

@bors try jobs=x86_64-msvc-*

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

rust-bors · 2026-04-20T12:45:50Z

☀️ Try build successful (CI)
Build commit: 6d8d88e (6d8d88e3ab7025c82dc5ed03d96874614fdf1189, parent: e22c616e4e87914135c1db261a03e0437255335e)

cezarbbb · 2026-04-20T12:56:04Z

@bors try jobs=aarch64-*

export symbols: support macos/windows(32/64) try-job: aarch64-*

cezarbbb · 2026-04-22T03:20:20Z

@bors try jobs=x86_64-msvc-*

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

rust-bors · 2026-04-22T06:12:00Z

☀️ Try build successful (CI)
Build commit: c0d471b (c0d471b340755a324f088edfb47b158c885cbe75, parent: f9988fefd3add01f414f52b414308e7872622fee)

cezarbbb · 2026-05-06T08:38:43Z

Since #156012 and this PR modified the same test file, after obtaining consent, I merged the fixes from #156012 into this PR and added @jchecahi as a co-author.

rustbot · 2026-05-30T08:00:43Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

cezarbbb · 2026-05-30T09:33:02Z

Thanks @bjorn3 for taking the time to review this PR. I've made some optimizations and rebased onto the latest main. Several weeks have passed since the last review, could you please take a look? I look forward to receiving your valuable advice:>

bjorn3 · 2026-06-11T13:57:12Z

+            // Accept both on Windows.
+            let scope = symbol.scope();
+            if scope != object::SymbolScope::Dynamic
+                && !(sess.target.is_like_windows && scope == object::SymbolScope::Linkage)


This should probably check sess.target.binary_format rather than Windows. UEFI also uses COFF.

View changes since the review

bjorn3 · 2026-06-11T13:58:19Z

+        // Mach-O: strip the leading underscore that all external symbols have.
+        // The Darwin linker's export_symbols will add it back.
+        name.strip_prefix('_').map(|s| Cow::Owned(s.to_string())).unwrap_or(Cow::Borrowed(name))
+    } else if sess.target.is_like_windows {


These two should also check sess.target.binary_format.

View changes since the review

bjorn3 · 2026-06-11T13:59:20Z

+    if sess.target.is_like_darwin {
+        // Mach-O: strip the leading underscore that all external symbols have.
+        // The Darwin linker's export_symbols will add it back.
+        name.strip_prefix('_').map(|s| Cow::Owned(s.to_string())).unwrap_or(Cow::Borrowed(name))


If the name doesn't start with an _, I believe it will not be exported by the linker. In either case returning the original name is wrong as the linker will look for format!("_{name}"), which likely doesn't exist.

View changes since the review

The return type of undecorate_c_symbol has been changed to Option<Cow<str>>. Symbols without the _ prefix now return None and are skipped instead of incorrectly returning the original name.

bjorn3 · 2026-06-11T14:00:25Z

+                // COFF 32-bit: strip calling-convention decorations.
+                if let Some(rest) = name.strip_prefix('@') {
+                    // fastcall: @foo@N -> foo
+                    rest.split_once('@')


Should these use rsplit_once?

View changes since the review

rustbot · 2026-06-11T14:01:04Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

Co-authored-by: Jesus Checa <101630491+jchecahi@users.noreply.github.com>

cezarbbb · 2026-06-12T06:19:21Z

@bors try jobs=aarch64-apple

export symbols: support macos/windows(32/64) try-job: aarch64-apple

rust-bors · 2026-06-12T09:20:43Z

☀️ Try build successful (CI)
Build commit: a78f1e6 (a78f1e60ea53757c3ac71ac0b7e9167ed15eeae5, parent: b30f3df3ba3c4c9de2f58f1a75dd9500b79b3f8d)

cezarbbb · 2026-06-12T09:22:09Z

@rustbot ready

bjorn3 · 2026-06-12T09:54:46Z

+    fallback: &'a str,
+) -> Cow<'a, str> {
+    if suffix.as_ref().parse::<u32>().is_ok() {
+        Cow::Owned(base.to_string())


Suggested change

Cow::Owned(base.to_string())

Cow::Borrowed(base)

would work too, right? Then strip_numeric_suffix can return &'a str instead.

View changes since the review

bjorn3 · 2026-06-12T09:55:13Z

+                            strip_numeric_suffix(base, suffix, stripped)
+                        } else {
+                            // cdecl: _foo -> foo
+                            Cow::Owned(stripped.to_string())


Suggested change

Cow::Owned(stripped.to_string())

Cow::Borrowed(stripped)

would work, right?

View changes since the review

bjorn3 · 2026-06-12T09:55:45Z

+        BinaryFormat::MachO => {
+            // Mach-O: strip the leading underscore that all external symbols have.
+            // The Darwin linker's export_symbols will add it back.
+            name.strip_prefix('_').map(|s| Cow::Owned(s.to_string()))


and this, allowing you to remove Cow entirely.

Suggested change

name.strip_prefix('_').map(|s| Cow::Owned(s.to_string()))

name.strip_prefix('_').map(|s| Cow::Borrowed(s))

View changes since the review

rustbot assigned wesleywiser Apr 20, 2026

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 Apr 20, 2026

rustbot assigned bjorn3 and unassigned wesleywiser Apr 20, 2026

rust-bors Bot pushed a commit that referenced this pull request Apr 20, 2026

Auto merge of #155535 - cezarbbb:cstyle-export-symbols, r=<try>

22e628f

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

This comment has been minimized.

Sign in to view

rust-bors Bot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 20, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Apr 20, 2026

Auto merge of #155535 - cezarbbb:cstyle-export-symbols, r=<try>

71d836c

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Apr 20, 2026

Auto merge of #155535 - cezarbbb:cstyle-export-symbols, r=<try>

6d8d88e

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Apr 20, 2026

Auto merge of #155535 - cezarbbb:cstyle-export-symbols, r=<try>

6bcaf55

export symbols: support macos/windows(32/64) try-job: aarch64-*

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Apr 22, 2026

Auto merge of #155535 - cezarbbb:cstyle-export-symbols, r=<try>

c0d471b

export symbols: support macos/windows(32/64) try-job: x86_64-msvc-*

teor2345 mentioned this pull request Apr 22, 2026

Use Rust to call C++ class member functions directly on Windows rustfoundation/interop-initiative#57

Open

cezarbbb mentioned this pull request May 6, 2026

tests: Fix cdylib-export-c-library-symbols to work with LTO-enabled CFLAGS #156012

Closed

cezarbbb force-pushed the cstyle-export-symbols branch from 3171abe to 1431f40 Compare May 6, 2026 08:34

cezarbbb force-pushed the cstyle-export-symbols branch from 1431f40 to 4332ade Compare May 30, 2026 08:00

This comment was marked as resolved.

Sign in to view

bjorn3 requested changes Jun 11, 2026

View reviewed changes

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 11, 2026

export symbols: support macos/windows(32/64)

a46ffc1

Co-authored-by: Jesus Checa <101630491+jchecahi@users.noreply.github.com>

cezarbbb force-pushed the cstyle-export-symbols branch from 4332ade to a46ffc1 Compare June 12, 2026 06:19

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Jun 12, 2026

Auto merge of #155535 - cezarbbb:cstyle-export-symbols, r=<try>

a78f1e6

export symbols: support macos/windows(32/64) try-job: aarch64-apple

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 12, 2026

cezarbbb requested a review from bjorn3 June 12, 2026 09:22

bjorn3 reviewed Jun 12, 2026

View reviewed changes

	name.strip_prefix('_').map(\|s\| Cow::Owned(s.to_string()))
	name.strip_prefix('_').map(\|s\| Cow::Borrowed(s))

Uh oh!

Conversation

cezarbbb commented Apr 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rustbot commented Apr 20, 2026

Uh oh!

cezarbbb commented Apr 20, 2026

Uh oh!

adwinwhite commented Apr 20, 2026

Uh oh!

rust-bors Bot commented Apr 20, 2026

Uh oh!

cezarbbb commented Apr 20, 2026

Uh oh!

cezarbbb commented Apr 20, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Apr 20, 2026

Uh oh!

cezarbbb commented Apr 20, 2026

Uh oh!

This comment has been minimized.

rust-bors Bot commented Apr 20, 2026

Uh oh!

This comment has been minimized.

cezarbbb commented Apr 20, 2026

Uh oh!

This comment has been minimized.

rust-bors Bot commented Apr 20, 2026

Uh oh!

cezarbbb commented Apr 20, 2026

Uh oh!

This comment has been minimized.

cezarbbb commented Apr 22, 2026

Uh oh!

This comment has been minimized.

rust-bors Bot commented Apr 22, 2026

Uh oh!

cezarbbb commented May 6, 2026

Uh oh!

rustbot commented May 30, 2026

Uh oh!

cezarbbb commented May 30, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

This comment was marked as resolved.

This comment was marked as resolved.

bjorn3 Jun 11, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

cezarbbb Jun 12, 2026

Choose a reason for hiding this comment

Uh oh!

bjorn3 Jun 11, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

cezarbbb Jun 12, 2026

Choose a reason for hiding this comment

Uh oh!

bjorn3 Jun 11, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

cezarbbb Jun 12, 2026

Choose a reason for hiding this comment

Uh oh!

bjorn3 Jun 11, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

cezarbbb Jun 12, 2026

Choose a reason for hiding this comment

Uh oh!

rustbot commented Jun 11, 2026

Uh oh!

cezarbbb commented Jun 12, 2026

cezarbbb commented Apr 20, 2026 •

edited

Loading

cezarbbb commented May 30, 2026 •

edited

Loading

bjorn3 Jun 11, 2026 •

edited by rustbot

Loading

bjorn3 Jun 11, 2026 •

edited by rustbot

Loading

bjorn3 Jun 11, 2026 •

edited by rustbot

Loading

bjorn3 Jun 11, 2026 •

edited by rustbot

Loading

bjorn3 Jun 12, 2026 •

edited by rustbot

Loading

bjorn3 Jun 12, 2026 •

edited by rustbot

Loading

bjorn3 Jun 12, 2026 •

edited by rustbot

Loading