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| author | David Lattimore <dvdlttmr@gmail.com> | 2024-10-11 07:58:36 +1100 |
|---|---|---|
| committer | David Lattimore <dvdlttmr@gmail.com> | 2024-10-11 08:43:27 +1100 |
| commit | 42c0494499b3ee271bafa68bbfe5eb5176442c4d (patch) | |
| tree | 36af6f1f1b24b9be2de03c497ebe6a5fecaa7bb2 | |
| parent | bfe5e8cef698ccc4fca655b4cdbabf78fed43816 (diff) | |
| download | rust-42c0494499b3ee271bafa68bbfe5eb5176442c4d.tar.gz rust-42c0494499b3ee271bafa68bbfe5eb5176442c4d.zip | |
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>
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/declare.rs | 7 | ||||
| -rw-r--r-- | tests/codegen/default-visibility.rs | 16 |
2 files changed, 19 insertions, 4 deletions
diff --git a/compiler/rustc_codegen_llvm/src/declare.rs b/compiler/rustc_codegen_llvm/src/declare.rs index 7be44dd51b5..33258cb46fa 100644 --- a/compiler/rustc_codegen_llvm/src/declare.rs +++ b/compiler/rustc_codegen_llvm/src/declare.rs @@ -84,10 +84,9 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> { unnamed: llvm::UnnamedAddr, fn_type: &'ll Type, ) -> &'ll Value { - // Declare C ABI functions with the visibility used by C by default. - let visibility = Visibility::from_generic(self.tcx.sess.default_visibility()); - - declare_raw_fn(self, name, llvm::CCallConv, unnamed, visibility, fn_type) + // Visibility should always be default for declarations, otherwise the linker may report an + // error. + declare_raw_fn(self, name, llvm::CCallConv, unnamed, Visibility::Default, fn_type) } /// Declare an entry Function diff --git a/tests/codegen/default-visibility.rs b/tests/codegen/default-visibility.rs index 884d386ec20..88ff9fee254 100644 --- a/tests/codegen/default-visibility.rs +++ b/tests/codegen/default-visibility.rs @@ -31,3 +31,19 @@ pub static tested_symbol: [u8; 6] = *b"foobar"; // 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 |