From: Lucas Ly Ba <[email protected]>
Warn when `#[no_mangle]` or `#[export_name]` is applied to a generic
function, since generic items must be mangled and the attribute has no
effect.
gcc/rust/ChangeLog:
* checks/lints/unused/rust-unused-checker.cc (UnusedChecker::visit):
Warn on a no-mangle generic function.
gcc/testsuite/ChangeLog:
* rust/compile/no-mangle-generic-items_0.rs: New test.
Signed-off-by: Lucas Ly Ba <[email protected]>
---
This change was merged into the gccrs repository and is posted here for
upstream visibility and potential drive-by review, as requested by GCC
release managers.
Each commit email contains a link to its details on github from where you can
find the Pull-Request and associated discussions.
Commit on github:
https://github.com/Rust-GCC/gccrs/commit/ab11f462825159529a085117f88c2214fc30e191
The commit has NOT been mentioned in any issue.
The commit has been mentioned in the following pull-request(s):
- https://github.com/Rust-GCC/gccrs/pull/4645
.../checks/lints/unused/rust-unused-checker.cc | 16 ++++++++++++++++
.../rust/compile/no-mangle-generic-items_0.rs | 10 ++++++++++
2 files changed, 26 insertions(+)
create mode 100644 gcc/testsuite/rust/compile/no-mangle-generic-items_0.rs
diff --git a/gcc/rust/checks/lints/unused/rust-unused-checker.cc
b/gcc/rust/checks/lints/unused/rust-unused-checker.cc
index 2c521634d..553a2f71e 100644
--- a/gcc/rust/checks/lints/unused/rust-unused-checker.cc
+++ b/gcc/rust/checks/lints/unused/rust-unused-checker.cc
@@ -152,6 +152,22 @@ UnusedChecker::visit (HIR::Function &fct)
rust_warning_at (fct.get_locus (), OPT_Wunused_variable,
"function %qs should have a snake case name",
fct.get_function_name ().as_string ().c_str ());
+
+ // The no_mangle_generic_items lint: a generic function cannot be exported
+ // with a fixed symbol, so `#[no_mangle]`/`#[export_name]` has no effect.
+ if (fct.has_generics ())
+ for (auto &attr : fct.get_outer_attrs ())
+ {
+ auto name = attr.get_path ().as_string ();
+ if (name == "no_mangle" || name == "export_name")
+ {
+ rust_warning_at (fct.get_locus (), OPT_Wattributes,
+ "generic functions must be mangled, %qs has no "
+ "effect",
+ name.c_str ());
+ break;
+ }
+ }
walk (fct);
}
diff --git a/gcc/testsuite/rust/compile/no-mangle-generic-items_0.rs
b/gcc/testsuite/rust/compile/no-mangle-generic-items_0.rs
new file mode 100644
index 000000000..5fa05ac2b
--- /dev/null
+++ b/gcc/testsuite/rust/compile/no-mangle-generic-items_0.rs
@@ -0,0 +1,10 @@
+// { dg-additional-options "-frust-unused-check-2.0" }
+#![feature(no_core, lang_items)]
+#![no_core]
+
+#[lang = "sized"]
+pub trait Sized {}
+
+#[no_mangle]
+pub fn f<T>(_x: T) {}
+// { dg-warning "generic functions must be mangled" "" { target *-*-* } .-1 }
base-commit: 414c389f8094a888a30966485489e3680149cbb7
--
2.54.0
