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rust/tests/codegen/default-visibility.rs
David Lattimore 42c0494499 Use Default visibility for rustc-generated C symbol declarations
Non-default visibilities should only be used for definitions, not
declarations, otherwise linking can fail.

Co-authored-by: Collin Baker <collinbaker@chromium.org>
2024-10-11 08:43:27 +11:00

50 lines
2.2 KiB
Rust

// Verifies that `Session::default_visibility` is affected when using the related cmdline
// flag. This is a regression test for https://github.com/rust-lang/compiler-team/issues/782. See
// also https://github.com/rust-lang/rust/issues/73295 and
// https://github.com/rust-lang/rust/issues/37530.
//@ revisions:DEFAULT HIDDEN PROTECTED INTERPOSABLE
//@[HIDDEN] compile-flags: -Zdefault-visibility=hidden
//@[PROTECTED] compile-flags: -Zdefault-visibility=protected
//@[INTERPOSABLE] compile-flags: -Zdefault-visibility=interposable
// The test scenario is specifically about visibility of symbols exported out of dynamically linked
// libraries.
#![crate_type = "dylib"]
// The test scenario needs to use a Rust-public, but non-explicitly-exported symbol
// (e.g. the test doesn't use `#[no_mangle]`, because currently it implies that
// the symbol should be exported; we don't want that - we want to test the *default*
// export setting instead).
#[used]
pub static tested_symbol: [u8; 6] = *b"foobar";
// Exact LLVM IR differs depending on the target triple (e.g. `hidden constant`
// vs `internal constant` vs `constant`). Because of this, we only apply the
// specific test expectations below to one specific target triple. If needed,
// additional targets can be covered by adding copies of this test file with
// a different `only-X` directive.
//
//@ only-x86_64-unknown-linux-gnu
// HIDDEN: @{{.*}}default_visibility{{.*}}tested_symbol{{.*}} = hidden constant
// PROTECTED: @{{.*}}default_visibility{{.*}}tested_symbol{{.*}} = protected constant
// INTERPOSABLE: @{{.*}}default_visibility{{.*}}tested_symbol{{.*}} = constant
// DEFAULT: @{{.*}}default_visibility{{.*}}tested_symbol{{.*}} = constant
pub fn do_memcmp(left: &[u8], right: &[u8]) -> i32 {
left.cmp(right) as i32
}
// CHECK: define {{.*}} @{{.*}}do_memcmp{{.*}} {
// CHECK: }
// `do_memcmp` should invoke core::intrinsic::compare_bytes which emits a call
// to the C symbol `memcmp` (at least on x86_64-unknown-linux-gnu). This symbol
// should *not* be declared hidden or protected.
// HIDDEN: declare i32 @memcmp
// PROTECTED: declare i32 @memcmp
// INTERPOSABLE: declare i32 @memcmp
// DEFAULT: declare i32 @memcmp