Rollup merge of #146766 - nikic:global-alloc-attr, r=nnethercote

Add attributes for #[global_allocator] functions

Emit `#[rustc_allocator]` etc. attributes on the functions generated by the `#[global_allocator]` macro, which will emit LLVM attributes like `"alloc-family"`. If the module with the global allocator participates in LTO, this ensures that the attributes typically emitted on the allocator declarations are not lost if the definition is imported.

There is a similar issue when the allocator shim is used, but I've opted not to fix that case in this PR, because doing that cleanly is somewhat gnarly.

Related to https://github.com/rust-lang/rust/issues/145995.

1 files changed, 41 insertions, 0 deletions

diff --git a/tests/codegen-llvm/global-allocator-attributes.rs b/tests/codegen-llvm/global-allocator-attributes.rs
new file mode 100644
index 00000000000..472ca772075
--- /dev/null
+++ b/tests/codegen-llvm/global-allocator-attributes.rs
@@ -0,0 +1,41 @@
+//@ compile-flags: -C opt-level=3
+#![crate_type = "lib"]
+
+mod foobar {
+    use std::alloc::{GlobalAlloc, Layout};
+
+    struct Allocator;
+
+    unsafe impl GlobalAlloc for Allocator {
+        unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+            // CHECK-LABEL: ; __rustc::__rust_alloc
+            // CHECK-NEXT: ; Function Attrs: {{.*}}allockind("alloc,uninitialized,aligned") allocsize(0){{.*}}
+            // CHECK-NEXT: define{{.*}} noalias{{.*}} ptr @{{.*}}__rust_alloc(i[[SIZE:[0-9]+]] {{.*}}%size, i[[SIZE]] allocalign{{.*}} %align)
+            panic!()
+        }
+
+        unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+            // CHECK-LABEL: ; __rustc::__rust_dealloc
+            // CHECK-NEXT: ; Function Attrs: {{.*}}allockind("free"){{.*}}
+            // CHECK-NEXT: define{{.*}} void @{{.*}}__rust_dealloc(ptr allocptr{{.*}} %ptr, i[[SIZE]] {{.*}} %size, i[[SIZE]] {{.*}} %align)
+            panic!()
+        }
+
+        unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+            // CHECK-LABEL: ; __rustc::__rust_realloc
+            // CHECK-NEXT: ; Function Attrs: {{.*}}allockind("realloc,aligned") allocsize(3){{.*}}
+            // CHECK-NEXT: define{{.*}} noalias{{.*}} ptr @{{.*}}__rust_realloc(ptr allocptr{{.*}} %ptr, i[[SIZE]] {{.*}} %size, i[[SIZE]] allocalign{{.*}} %align, i[[SIZE]] {{.*}} %new_size)
+            panic!()
+        }
+
+        unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+            // CHECK-LABEL: ; __rustc::__rust_alloc_zeroed
+            // CHECK-NEXT: ; Function Attrs: {{.*}}allockind("alloc,zeroed,aligned") allocsize(0){{.*}}
+            // CHECK-NEXT: define{{.*}} noalias{{.*}} ptr @{{.*}}__rust_alloc_zeroed(i[[SIZE]] {{.*}} %size, i[[SIZE]] allocalign{{.*}} %align)
+            panic!()
+        }
+    }
+
+    #[global_allocator]
+    static GLOBAL: Allocator = Allocator;
+}