Auto merge of #75549 - tmandry:rollup-sxjwa0w, r=tmandry

Rollup of 4 pull requests

Successful merges:

 - #75376 (Set CMAKE_SYSTEM_NAME when cross-compiling)
 - #75448 (merge `as_local_hir_id` with `local_def_id_to_hir_id`)
 - #75513 (Recover gracefully from `struct` parse errors)
 - #75545 (std/sys/unix/time: make it easier for LLVM to optimize `Instant` subtraction.)

Failed merges:

 - #75514 (Replaced `log` with `tracing`)

r? @ghost

Author: bors

library/std/src/sys/unix/time.rs

@@ -20,17 +20,29 @@ impl Timespec {
 
     fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {
         if self >= other {
-            Ok(if self.t.tv_nsec >= other.t.tv_nsec {
-                Duration::new(
-                    (self.t.tv_sec - other.t.tv_sec) as u64,
-                    (self.t.tv_nsec - other.t.tv_nsec) as u32,
-                )
+            // NOTE(eddyb) two aspects of this `if`-`else` are required for LLVM
+            // to optimize it into a branchless form (see also #75545):
+            //
+            // 1. `self.t.tv_sec - other.t.tv_sec` shows up as a common expression
+            //    in both branches, i.e. the `else` must have its `- 1`
+            //    subtraction after the common one, not interleaved with it
+            //    (it used to be `self.t.tv_sec - 1 - other.t.tv_sec`)
+            //
+            // 2. the `Duration::new` call (or any other additional complexity)
+            //    is outside of the `if`-`else`, not duplicated in both branches
+            //
+            // Ideally this code could be rearranged such that it more
+            // directly expresses the lower-cost behavior we want from it.
+            let (secs, nsec) = if self.t.tv_nsec >= other.t.tv_nsec {
+                ((self.t.tv_sec - other.t.tv_sec) as u64, (self.t.tv_nsec - other.t.tv_nsec) as u32)
             } else {
-                Duration::new(
-                    (self.t.tv_sec - 1 - other.t.tv_sec) as u64,
+                (
+                    (self.t.tv_sec - other.t.tv_sec - 1) as u64,
                     self.t.tv_nsec as u32 + (NSEC_PER_SEC as u32) - other.t.tv_nsec as u32,
                 )
-            })
+            };
+
+            Ok(Duration::new(secs, nsec))
         } else {
             match other.sub_timespec(self) {
                 Ok(d) => Err(d),

src/bootstrap/native.rs

@@ -282,14 +282,6 @@ impl Step for Llvm {
                 "LLVM_CONFIG_PATH",
                 host_bin.join("llvm-config").with_extension(EXE_EXTENSION),
             );
-
-            if target.contains("netbsd") {
-                cfg.define("CMAKE_SYSTEM_NAME", "NetBSD");
-            } else if target.contains("freebsd") {
-                cfg.define("CMAKE_SYSTEM_NAME", "FreeBSD");
-            } else if target.contains("windows") {
-                cfg.define("CMAKE_SYSTEM_NAME", "Windows");
-            }
         }
 
         if let Some(ref suffix) = builder.config.llvm_version_suffix {
@@ -378,6 +370,22 @@ fn configure_cmake(
     }
     cfg.target(&target.triple).host(&builder.config.build.triple);
 
+    if target != builder.config.build {
+        if target.contains("netbsd") {
+            cfg.define("CMAKE_SYSTEM_NAME", "NetBSD");
+        } else if target.contains("freebsd") {
+            cfg.define("CMAKE_SYSTEM_NAME", "FreeBSD");
+        } else if target.contains("windows") {
+            cfg.define("CMAKE_SYSTEM_NAME", "Windows");
+        }
+        // When cross-compiling we should also set CMAKE_SYSTEM_VERSION, but in
+        // that case like CMake we cannot easily determine system version either.
+        //
+        // Since, the LLVM itself makes rather limited use of version checks in
+        // CMakeFiles (and then only in tests), and so far no issues have been
+        // reported, the system version is currently left unset.
+    }
+
     let sanitize_cc = |cc: &Path| {
         if target.contains("msvc") {
             OsString::from(cc.to_str().unwrap().replace("\\", "/"))

src/librustc_codegen_llvm/consts.rs

@@ -215,7 +215,7 @@ impl CodegenCx<'ll, 'tcx> {
         debug!("get_static: sym={} instance={:?}", sym, instance);
 
         let g = if let Some(def_id) = def_id.as_local() {
-            let id = self.tcx.hir().as_local_hir_id(def_id);
+            let id = self.tcx.hir().local_def_id_to_hir_id(def_id);
             let llty = self.layout_of(ty).llvm_type(self);
             // FIXME: refactor this to work without accessing the HIR
             let (g, attrs) = match self.tcx.hir().get(id) {

src/librustc_codegen_ssa/back/symbol_export.rs

@@ -361,7 +361,7 @@ fn upstream_drop_glue_for_provider<'tcx>(
 
 fn is_unreachable_local_definition_provider(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     if let Some(def_id) = def_id.as_local() {
-        !tcx.reachable_set(LOCAL_CRATE).contains(&tcx.hir().as_local_hir_id(def_id))
+        !tcx.reachable_set(LOCAL_CRATE).contains(&tcx.hir().local_def_id_to_hir_id(def_id))
     } else {
         bug!("is_unreachable_local_definition called with non-local DefId: {:?}", def_id)
     }

src/librustc_hir/definitions.rs

@@ -306,11 +306,6 @@ impl Definitions {
         })
     }
 
-    #[inline]
-    pub fn as_local_hir_id(&self, def_id: LocalDefId) -> hir::HirId {
-        self.local_def_id_to_hir_id(def_id)
-    }
-
     #[inline]
     pub fn local_def_id_to_hir_id(&self, id: LocalDefId) -> hir::HirId {
         self.def_id_to_hir_id[id].unwrap()

src/librustc_infer/infer/error_reporting/mod.rs

@@ -144,7 +144,7 @@ fn msg_span_from_early_bound_and_free_regions(
     let sm = tcx.sess.source_map();
 
     let scope = region.free_region_binding_scope(tcx);
-    let node = tcx.hir().as_local_hir_id(scope.expect_local());
+    let node = tcx.hir().local_def_id_to_hir_id(scope.expect_local());
     let tag = match tcx.hir().find(node) {
         Some(Node::Block(_) | Node::Expr(_)) => "body",
         Some(Node::Item(it)) => item_scope_tag(&it),
@@ -1707,7 +1707,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             .in_progress_typeck_results
             .map(|typeck_results| typeck_results.borrow().hir_owner)
             .map(|owner| {
-                let hir_id = hir.as_local_hir_id(owner);
+                let hir_id = hir.local_def_id_to_hir_id(owner);
                 let parent_id = hir.get_parent_item(hir_id);
                 (
                     // Parent item could be a `mod`, so we check the HIR before calling:
@@ -1733,7 +1733,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         // Get the `hir::Param` to verify whether it already has any bounds.
                         // We do this to avoid suggesting code that ends up as `T: 'a'b`,
                         // instead we suggest `T: 'a + 'b` in that case.
-                        let id = hir.as_local_hir_id(def_id);
+                        let id = hir.local_def_id_to_hir_id(def_id);
                         let mut has_bounds = false;
                         if let Node::GenericParam(param) = hir.get(id) {
                             has_bounds = !param.bounds.is_empty();
@@ -1786,7 +1786,10 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             .and_then(|(_, g)| g.params.first())
             .and_then(|param| param.def_id.as_local())
             .map(|def_id| {
-                (hir.span(hir.as_local_hir_id(def_id)).shrink_to_lo(), format!("{}, ", new_lt))
+                (
+                    hir.span(hir.local_def_id_to_hir_id(def_id)).shrink_to_lo(),
+                    format!("{}, ", new_lt),
+                )
             });
 
         let labeled_user_string = match bound_kind {

src/librustc_infer/infer/error_reporting/nice_region_error/find_anon_type.rs

@@ -28,7 +28,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         br: &ty::BoundRegion,
     ) -> Option<(&hir::Ty<'tcx>, &hir::FnDecl<'tcx>)> {
         if let Some(anon_reg) = self.tcx().is_suitable_region(region) {
-            let hir_id = self.tcx().hir().as_local_hir_id(anon_reg.def_id);
+            let hir_id = self.tcx().hir().local_def_id_to_hir_id(anon_reg.def_id);
             let fndecl = match self.tcx().hir().get(hir_id) {
                 Node::Item(&hir::Item { kind: hir::ItemKind::Fn(ref m, ..), .. })
                 | Node::TraitItem(&hir::TraitItem {

src/librustc_infer/infer/error_reporting/nice_region_error/trait_impl_difference.rs

@@ -67,7 +67,8 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         match assoc_item.kind {
             ty::AssocKind::Fn => {
                 let hir = self.tcx().hir();
-                if let Some(hir_id) = assoc_item.def_id.as_local().map(|id| hir.as_local_hir_id(id))
+                if let Some(hir_id) =
+                    assoc_item.def_id.as_local().map(|id| hir.local_def_id_to_hir_id(id))
                 {
                     if let Some(decl) = hir.fn_decl_by_hir_id(hir_id) {
                         visitor.visit_fn_decl(decl);

src/librustc_infer/infer/error_reporting/nice_region_error/util.rs

@@ -49,7 +49,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         };
 
         let hir = &self.tcx().hir();
-        let hir_id = hir.as_local_hir_id(id.as_local()?);
+        let hir_id = hir.local_def_id_to_hir_id(id.as_local()?);
         let body_id = hir.maybe_body_owned_by(hir_id)?;
         let body = hir.body(body_id);
         let owner_id = hir.body_owner(body_id);

src/librustc_lint/builtin.rs

@@ -440,7 +440,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
                 // reported for missing docs.
                 let real_trait = trait_ref.path.res.def_id();
                 if let Some(def_id) = real_trait.as_local() {
-                    let hir_id = cx.tcx.hir().as_local_hir_id(def_id);
+                    let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
                     if let Some(Node::Item(item)) = cx.tcx.hir().find(hir_id) {
                         if let hir::VisibilityKind::Inherited = item.vis.node {
                             for impl_item_ref in items {
@@ -614,7 +614,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDebugImplementations {
             cx.tcx.for_each_impl(debug, |d| {
                 if let Some(ty_def) = cx.tcx.type_of(d).ty_adt_def() {
                     if let Some(def_id) = ty_def.did.as_local() {
-                        impls.insert(cx.tcx.hir().as_local_hir_id(def_id));
+                        impls.insert(cx.tcx.hir().local_def_id_to_hir_id(def_id));
                     }
                 }
             });