Commit 5cd16b7f2bc3624f2d658aa87151279878d2652a | rust

author	bors <bors@rust-lang.org> 2025-01-16 02:31:22 UTC
committer	bors <bors@rust-lang.org> 2025-01-16 02:31:22 UTC
log	5cd16b7f2bc3624f2d658aa87151279878d2652a
tree	6180a5f11979ce30f0495a64c57ca6d265a4f670
parent	6fc8a27931b3806d38143c518c91c7f97b4cfb83
parent	98f673e93a47b33a451f6b2cd99e5d5b03b57563

Auto merge of #135458 - jieyouxu:migrate-extern-fn-reachable, r=lqd

tests: Port `extern-fn-reachable` to rmake.rs

Part of #121876.

## Summary

This PR ports `tests/run-make/extern-fn-reachable` to use `rmake.rs`. Notable changes:

- We now use the `object` crate and look at the exported symbols specifically.
- This test's coverage regressed against windows-msvc back in [replace dynamic library module with libloading #90716](https://github.com/rust-lang/rust/pull/90716), but since we use `object` now, we're able to claw the test coverage back.
- The checks are now stricter:
    1. It no longer looks for substring symbol matches in `nm` textual outputs, it inspects the symbol names precisely.
    2. We now also explicitly check for the presence of leading underscore in exported symbol names on apple vs non-apple targets.
- Added another case of `#[no_mangle] fn fun6() {}` (note the lack of `pub`) to check that Rust nameres visibility is orthogonal to symbol visibility in dylib.

## History

- Test was initially introduced as a run-pass[^run-pass] test as part of [Don't mark reachable extern fns as internal #10539](https://github.com/rust-lang/rust/pull/10539).
- Test re-introduced as a run-make test in https://github.com/rust-lang/rust/pull/13741.
- Later, the test coverage regressed in https://github.com/rust-lang/rust/pull/90716.

[^run-pass]: no longer a thing nowadays

Supersedes #128314.
Co-authored with `@lolbinarycat.`

try-job: x86_64-msvc
try-job: i686-msvc
try-job: i686-mingw
try-job: x86_64-mingw-1
try-job: x86_64-apple-1
try-job: aarch64-apple
try-job: test-various

4 files changed, 61 insertions(+), 27 deletions(-)

src/tools/tidy/src/allowed_run_make_makefiles.txt-1

...	...	@@ -1,5 +1,4 @@
1	1	run-make/cat-and-grep-sanity-check/Makefile
2		run-make/extern-fn-reachable/Makefile
3	2	run-make/jobserver-error/Makefile
4	3	run-make/split-debuginfo/Makefile
5	4	run-make/symbol-mangling-hashed/Makefile

tests/run-make/extern-fn-reachable/Makefile deleted-26

...	...	@@ -1,26 +0,0 @@
1		# ignore-cross-compile
2		include ../tools.mk
3
4		# ignore-windows-msvc
5
6		NM=nm -D
7
8		ifeq ($(UNAME),Darwin)
9		NM=nm -gU
10		endif
11
12		ifdef IS_WINDOWS
13		NM=nm -g
14		endif
15
16		# This overrides the LD_LIBRARY_PATH for RUN
17		TARGET_RPATH_DIR:=$(TARGET_RPATH_DIR):$(TMPDIR)
18
19		all:
20		$(RUSTC) dylib.rs -o $(TMPDIR)/libdylib.so -C prefer-dynamic
21
22		[ "$$($(NM) $(TMPDIR)/libdylib.so \| grep -v __imp_ \| grep -c fun1)" -eq "1" ]
23		[ "$$($(NM) $(TMPDIR)/libdylib.so \| grep -v __imp_ \| grep -c fun2)" -eq "1" ]
24		[ "$$($(NM) $(TMPDIR)/libdylib.so \| grep -v __imp_ \| grep -c fun3)" -eq "1" ]
25		[ "$$($(NM) $(TMPDIR)/libdylib.so \| grep -v __imp_ \| grep -c fun4)" -eq "1" ]
26		[ "$$($(NM) $(TMPDIR)/libdylib.so \| grep -v __imp_ \| grep -c fun5)" -eq "1" ]

tests/run-make/extern-fn-reachable/dylib.rs+15

...	...	@@ -1,19 +1,34 @@
1	1	#![crate_type = "dylib"]
2	2	#![allow(dead_code)]
3	3
	4	// `pub` extern fn here is a Rust nameres visibility concept, and should not affect symbol
	5	// visibility in the dylib.
4	6	#[no_mangle]
5	7	pub extern "C" fn fun1() {}
	8
	9	// (Lack of) `pub` for the extern fn here is a Rust nameres visibility concept, and should not
	10	// affect symbol visibility in the dylib.
6	11	#[no_mangle]
7	12	extern "C" fn fun2() {}
8	13
	14	// Modules are a Rust nameres concept, and should not affect symbol visibility in the dylib if the
	15	// extern fn is nested inside a module.
9	16	mod foo {
10	17	#[no_mangle]
11	18	pub extern "C" fn fun3() {}
12	19	}
	20
	21	// Similarly, the Rust visibility of the containing module is a Rust nameres concept, and should not
	22	// affect symbol visibility in the dylib.
13	23	pub mod bar {
14	24	#[no_mangle]
15	25	pub extern "C" fn fun4() {}
16	26	}
17	27
	28	// Non-extern `#[no_mangle]` fn should induce a symbol visible in the dylib.
18	29	#[no_mangle]
19	30	pub fn fun5() {}
	31
	32	// The Rust visibility of the fn should not affect is symbol visibility in the dylib.
	33	#[no_mangle]
	34	fn fun6() {}

tests/run-make/extern-fn-reachable/rmake.rs created+46

...	...	@@ -0,0 +1,46 @@
	1	//! Smoke test to check that that symbols of `extern "C"` functions and `#[no_mangle]` rust
	2	//! functions:
	3	//!
	4	//! 1. Are externally visible in the dylib produced.
	5	//! 2. That the symbol visibility is orthogonal to the Rust nameres visibility of the functions
	6	//! involved.
	7
	8	//@ ignore-cross-compile
	9
	10	use std::collections::BTreeSet;
	11
	12	use run_make_support::object::{self, Object};
	13	use run_make_support::{dynamic_lib_name, is_darwin, path, rfs, rustc};
	14
	15	fn main() {
	16	let dylib = dynamic_lib_name("dylib");
	17	rustc().input("dylib.rs").output(&dylib).arg("-Cprefer-dynamic").run();
	18
	19	let expected_symbols = if is_darwin() {
	20	// Mach-O states that all exported symbols should have an underscore as prefix. At the
	21	// same time dlsym will implicitly add it, so outside of compilers, linkers and people
	22	// writing assembly, nobody needs to be aware of this.
	23	BTreeSet::from(["_fun1", "_fun2", "_fun3", "_fun4", "_fun5", "_fun6"])
	24	} else {
	25	BTreeSet::from(["fun1", "fun2", "fun3", "fun4", "fun5", "fun6"])
	26	};
	27
	28	let mut found_symbols = BTreeSet::new();
	29
	30	let blob = rfs::read(path(dylib));
	31	let file = object::File::parse(&*blob).unwrap();
	32	for export in file.exports().unwrap() {
	33	let sym_name = export.name();
	34	let sym_name = std::str::from_utf8(sym_name).unwrap();
	35	found_symbols.insert(sym_name);
	36	}
	37
	38	println!("expected_symbols = {:?}", expected_symbols);
	39	println!("found_symbols = {:?}", found_symbols);
	40	if !found_symbols.is_superset(&expected_symbols) {
	41	for diff in expected_symbols.difference(&found_symbols) {
	42	eprintln!("missing symbol: {}", diff);
	43	}
	44	panic!("missing expected symbols");
	45	}
	46	}