Auto merge of #81113 - m-ou-se:rollup-a1unz4x, r=m-ou-se

Rollup of 13 pull requests

Successful merges:

 - #79298 (correctly deal with late-bound lifetimes in anon consts)
 - #80031 (resolve: Reject ambiguity built-in attr vs different built-in attr)
 - #80201 (Add benchmark and fast path for BufReader::read_exact)
 - #80635 (Improve diagnostics when closure doesn't meet trait bound)
 - #80765 (resolve: Simplify collection of traits in scope)
 - #80932 (Allow downloading LLVM on Windows and MacOS)
 - #80983 (Remove is_dllimport_foreign_item definition from cg_ssa)
 - #81064 (Support non-stage0 check)
 - #81080 (Force vec![] to expression position only)
 - #81082 (BTreeMap: clean up a few more comments)
 - #81084 (Use Option::map instead of open-coding it)
 - #81095 (Use Option::unwrap_or instead of open-coding it)
 - #81107 (Add NonZeroUn::is_power_of_two)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -214,11 +214,7 @@ fn handle_native(name: &str) -> &str {
 }
 
 pub fn target_cpu(sess: &Session) -> &str {
-    let name = match sess.opts.cg.target_cpu {
-        Some(ref s) => &**s,
-        None => &*sess.target.cpu,
-    };
-
+    let name = sess.opts.cg.target_cpu.as_ref().unwrap_or(&sess.target.cpu);
     handle_native(name)
 }
 
@@ -254,8 +250,6 @@ pub fn handle_native_features(sess: &Session) -> Vec<String> {
 }
 
 pub fn tune_cpu(sess: &Session) -> Option<&str> {
-    match sess.opts.debugging_opts.tune_cpu {
-        Some(ref s) => Some(handle_native(&**s)),
-        None => None,
-    }
+    let name = sess.opts.debugging_opts.tune_cpu.as_ref()?;
+    Some(handle_native(name))
 }

compiler/rustc_codegen_ssa/src/base.rs

@@ -29,7 +29,6 @@ use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{self, EntryFnType};
-use rustc_session::utils::NativeLibKind;
 use rustc_session::Session;
 use rustc_target::abi::{Align, LayoutOf, VariantIdx};
 
@@ -817,32 +816,6 @@ pub fn provide_both(providers: &mut Providers) {
         }
         tcx.sess.opts.optimize
     };
-
-    providers.dllimport_foreign_items = |tcx, krate| {
-        let module_map = tcx.foreign_modules(krate);
-
-        let dllimports = tcx
-            .native_libraries(krate)
-            .iter()
-            .filter(|lib| {
-                if !matches!(lib.kind, NativeLibKind::Dylib | NativeLibKind::Unspecified) {
-                    return false;
-                }
-                let cfg = match lib.cfg {
-                    Some(ref cfg) => cfg,
-                    None => return true,
-                };
-                attr::cfg_matches(cfg, &tcx.sess.parse_sess, None)
-            })
-            .filter_map(|lib| lib.foreign_module)
-            .map(|id| &module_map[&id])
-            .flat_map(|module| module.foreign_items.iter().cloned())
-            .collect();
-        dllimports
-    };
-
-    providers.is_dllimport_foreign_item =
-        |tcx, def_id| tcx.dllimport_foreign_items(def_id.krate).contains(&def_id);
 }
 
 fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {