From: Lucas Ly Ba <[email protected]>
Warn on taking a reference to a mutable static, which is discouraged as
it can easily lead to undefined behaviour.
gcc/rust/ChangeLog:
* checks/lints/unused/rust-unused-checker.cc (UnusedChecker::visit):
New.
* checks/lints/unused/rust-unused-checker.h (UnusedChecker::visit):
New.
* rust-lang.cc (grs_langhook_init_options_struct): Enable warn_unused.
gcc/testsuite/ChangeLog:
* rust/compile/static-mut-refs_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/878be01f1008a0002dca30d8f5cbf7a85451717a
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/4646
.../lints/unused/rust-unused-checker.cc | 20 +++++++++++++++++++
.../checks/lints/unused/rust-unused-checker.h | 1 +
.../rust/compile/static-mut-refs_0.rs | 13 ++++++++++++
3 files changed, 34 insertions(+)
create mode 100644 gcc/testsuite/rust/compile/static-mut-refs_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 0d091e647..fffe61dd1 100644
--- a/gcc/rust/checks/lints/unused/rust-unused-checker.cc
+++ b/gcc/rust/checks/lints/unused/rust-unused-checker.cc
@@ -347,5 +347,25 @@ UnusedChecker::visit (HIR::LetStmt &stmt)
walk (stmt);
}
+void
+UnusedChecker::visit (HIR::BorrowExpr &expr)
+{
+ // The static_mut_refs lint: taking a reference to a mutable static is
+ // discouraged as it can easily lead to undefined behaviour.
+ NodeId ast_node_id = expr.get_expr ().get_mappings ().get_nodeid ();
+ if (auto def
+ = nr_context.lookup (ast_node_id, Resolver2_0::Namespace::Values))
+ if (auto id = mappings.lookup_node_to_hir (*def))
+ if (auto item = mappings.lookup_hir_item (*id))
+ if (item.value ()->get_item_kind () == HIR::Item::ItemKind::Static)
+ {
+ auto &static_item = static_cast<HIR::StaticItem &> (*item.value ());
+ if (static_item.is_mut ())
+ rust_warning_at (expr.get_locus (), OPT_Wunused,
+ "creating a reference to a mutable static");
+ }
+ walk (expr);
+}
+
} // namespace Analysis
} // namespace Rust
diff --git a/gcc/rust/checks/lints/unused/rust-unused-checker.h
b/gcc/rust/checks/lints/unused/rust-unused-checker.h
index 46e012e79..161f59b8a 100644
--- a/gcc/rust/checks/lints/unused/rust-unused-checker.h
+++ b/gcc/rust/checks/lints/unused/rust-unused-checker.h
@@ -52,6 +52,7 @@ private:
virtual void visit (HIR::MatchExpr &expr) override;
virtual void visit (HIR::ExternBlock &block) override;
virtual void visit (HIR::LetStmt &stmt) override;
+ virtual void visit (HIR::BorrowExpr &expr) override;
virtual void visit_loop_label (HIR::LoopLabel &label) override;
};
} // namespace Analysis
diff --git a/gcc/testsuite/rust/compile/static-mut-refs_0.rs
b/gcc/testsuite/rust/compile/static-mut-refs_0.rs
new file mode 100644
index 000000000..5dcc5978a
--- /dev/null
+++ b/gcc/testsuite/rust/compile/static-mut-refs_0.rs
@@ -0,0 +1,13 @@
+// { dg-additional-options "-frust-unused-check-2.0" }
+#![feature(no_core, lang_items)]
+#![no_core]
+
+#[lang = "sized"]
+pub trait Sized {}
+
+static mut S: i32 = 0;
+
+pub unsafe fn f() {
+ let _y = &S;
+// { dg-warning "reference to a mutable static" "" { target *-*-* } .-1 }
+}
base-commit: 064dddd85984adb7d47ad2d552d70c1295fcdbe8
--
2.54.0
