From 6318db1c5a06a08a6b4063b25a63df3c328a5bd7 Mon Sep 17 00:00:00 2001
From: jumbatm <30644300+jumbatm@users.noreply.github.com>
Date: Sat, 12 Dec 2020 13:26:43 +1000
Subject: [PATCH 1/4] Add test case for wasm non-clash.
---
src/test/ui/lint/clashing-extern-fn-wasm.rs | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
create mode 100644 src/test/ui/lint/clashing-extern-fn-wasm.rs
diff --git a/src/test/ui/lint/clashing-extern-fn-wasm.rs b/src/test/ui/lint/clashing-extern-fn-wasm.rs
new file mode 100644
index 0000000000000..eeb2b8eae2566
--- /dev/null
+++ b/src/test/ui/lint/clashing-extern-fn-wasm.rs
@@ -0,0 +1,21 @@
+// check-pass
+#![crate_type = "lib"]
+
+#[cfg(target_arch = "wasm32")]
+mod wasm_non_clash {
+ mod a {
+ #[link(wasm_import_module = "a")]
+ extern "C" {
+ pub fn foo();
+ }
+ }
+
+ mod b {
+ #[link(wasm_import_module = "b")]
+ extern "C" {
+ pub fn foo() -> usize;
+ // #79581: These declarations shouldn't clash because foreign fn names are mangled
+ // on wasm32.
+ }
+ }
+}
From 15c64a181b93584572f568a4c135a0fdb2870eb6 Mon Sep 17 00:00:00 2001
From: jumbatm <30644300+jumbatm@users.noreply.github.com>
Date: Sun, 13 Dec 2020 23:02:32 +1000
Subject: [PATCH 2/4] Use tcx.symbol_name to check for clashes.
---
compiler/rustc_lint/src/builtin.rs | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 374bd6d0d791f..0ef67a1355605 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -43,6 +43,7 @@ use rustc_index::vec::Idx;
use rustc_middle::lint::LintDiagnosticBuilder;
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::subst::{GenericArgKind, Subst};
+use rustc_middle::ty::Instance;
use rustc_middle::ty::{self, layout::LayoutError, Ty, TyCtxt};
use rustc_session::Session;
use rustc_span::edition::Edition;
@@ -2595,7 +2596,7 @@ declare_lint! {
}
pub struct ClashingExternDeclarations {
- seen_decls: FxHashMap<Symbol, HirId>,
+ seen_decls: FxHashMap<String, HirId>,
}
/// Differentiate between whether the name for an extern decl came from the link_name attribute or
@@ -2626,16 +2627,17 @@ impl ClashingExternDeclarations {
fn insert(&mut self, tcx: TyCtxt<'_>, fi: &hir::ForeignItem<'_>) -> Option<HirId> {
let hid = fi.hir_id;
- let name =
- &tcx.codegen_fn_attrs(tcx.hir().local_def_id(hid)).link_name.unwrap_or(fi.ident.name);
-
- if self.seen_decls.contains_key(name) {
+ let local_did = tcx.hir().local_def_id(fi.hir_id);
+ let did = local_did.to_def_id();
+ let instance = Instance::new(did, ty::List::identity_for_item(tcx, did));
+ let name = tcx.symbol_name(instance).name.to_string();
+ if self.seen_decls.contains_key(&name) {
// Avoid updating the map with the new entry when we do find a collision. We want to
// make sure we're always pointing to the first definition as the previous declaration.
// This lets us avoid emitting "knock-on" diagnostics.
- Some(*self.seen_decls.get(name).unwrap())
+ Some(*self.seen_decls.get(&name).unwrap())
} else {
- self.seen_decls.insert(*name, hid)
+ self.seen_decls.insert(name, hid)
}
}
From 7a46a4f2197c6ff1026d2bd81480165ad0b43bbc Mon Sep 17 00:00:00 2001
From: jumbatm <30644300+jumbatm@users.noreply.github.com>
Date: Wed, 23 Dec 2020 00:26:04 +1000
Subject: [PATCH 3/4] Remove unnecessary allocation.
---
compiler/rustc_lint/src/builtin.rs | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 0ef67a1355605..131d783ce4e2c 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -2630,14 +2630,14 @@ impl ClashingExternDeclarations {
let local_did = tcx.hir().local_def_id(fi.hir_id);
let did = local_did.to_def_id();
let instance = Instance::new(did, ty::List::identity_for_item(tcx, did));
- let name = tcx.symbol_name(instance).name.to_string();
- if self.seen_decls.contains_key(&name) {
+ let name = tcx.symbol_name(instance).name;
+ if let Some(&hir_id) = self.seen_decls.get(name) {
// Avoid updating the map with the new entry when we do find a collision. We want to
// make sure we're always pointing to the first definition as the previous declaration.
// This lets us avoid emitting "knock-on" diagnostics.
- Some(*self.seen_decls.get(&name).unwrap())
+ Some(hir_id)
} else {
- self.seen_decls.insert(name, hid)
+ self.seen_decls.insert(name.to_owned(), hid)
}
}
From 4b740acea270464758a3c81ea4341d858064ee28 Mon Sep 17 00:00:00 2001
From: jumbatm <30644300+jumbatm@users.noreply.github.com>
Date: Wed, 23 Dec 2020 00:34:26 +1000
Subject: [PATCH 4/4] Add FIXME note about storing &'tcx str
---
compiler/rustc_lint/src/builtin.rs | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 131d783ce4e2c..20e476b38ccac 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -2596,6 +2596,11 @@ declare_lint! {
}
pub struct ClashingExternDeclarations {
+ /// Map of function symbol name to the first-seen hir id for that symbol name.. If seen_decls
+ /// contains an entry for key K, it means a symbol with name K has been seen by this lint and
+ /// the symbol should be reported as a clashing declaration.
+ // FIXME: Technically, we could just store a &'tcx str here without issue; however, the
+ // `impl_lint_pass` macro doesn't currently support lints parametric over a lifetime.
seen_decls: FxHashMap<String, HirId>,
}