Rollup of 13 pull requests

Cargo.lock

@@ -600,6 +600,7 @@ dependencies = [
  "serde_json",
  "tempfile",
  "termize",
+ "tikv-jemalloc-sys",
  "toml 0.9.7",
  "ui_test",
  "walkdir",
@@ -4806,6 +4807,7 @@ dependencies = [
  "stringdex",
  "tempfile",
  "threadpool",
+ "tikv-jemalloc-sys",
  "tracing",
  "tracing-subscriber",
  "tracing-tree",
@@ -5537,9 +5539,9 @@ version = "0.1.0"
 
 [[package]]
 name = "tikv-jemalloc-sys"
-version = "0.6.0+5.3.0-1-ge13ca993e8ccb9ba9847cc330696e02839f328f7"
+version = "0.6.1+5.3.0-1-ge13ca993e8ccb9ba9847cc330696e02839f328f7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd3c60906412afa9c2b5b5a48ca6a5abe5736aec9eb48ad05037a677e52e4e2d"
+checksum = "cd8aa5b2ab86a2cefa406d889139c162cbb230092f7d1d7cbc1716405d852a3b"
 dependencies = [
  "cc",
  "libc",

compiler/rustc/Cargo.toml

@@ -21,9 +21,9 @@ rustc_public_bridge = { path = "../rustc_public_bridge" }
 # tidy-alphabetical-end
 
 [dependencies.tikv-jemalloc-sys]
-version = "0.6.0"
+version = "0.6.1"
 optional = true
-features = ['unprefixed_malloc_on_supported_platforms']
+features = ['override_allocator_on_supported_platforms']
 
 [features]
 # tidy-alphabetical-start

compiler/rustc/src/main.rs

@@ -7,26 +7,25 @@
 // distribution. The obvious way to do this is with the `#[global_allocator]`
 // mechanism. However, for complicated reasons (see
 // https://github.com/rust-lang/rust/pull/81782#issuecomment-784438001 for some
-// details) that mechanism doesn't work here. Also, we must use a consistent
-// allocator across the rustc <-> llvm boundary, and `#[global_allocator]`
-// wouldn't provide that.
+// details) that mechanism doesn't work here. Also, we'd like to use a
+// consistent allocator across the rustc <-> llvm boundary, and
+// `#[global_allocator]` wouldn't provide that.
 //
-// Instead, we use a lower-level mechanism. rustc is linked with jemalloc in a
-// way such that jemalloc's implementation of `malloc`, `free`, etc., override
-// the libc allocator's implementation. This means that Rust's `System`
-// allocator, which calls `libc::malloc()` et al., is actually calling into
-// jemalloc.
+// Instead, we use a lower-level mechanism, namely the
+// `"override_allocator_on_supported_platforms"` Cargo feature of jemalloc-sys.
+//
+// This makes jemalloc-sys override the libc/system allocator's implementation
+// of `malloc`, `free`, etc.. This means that Rust's `System` allocator, which
+// calls `libc::malloc()` et al., is actually calling into jemalloc.
 //
 // A consequence of not using `GlobalAlloc` (and the `tikv-jemallocator` crate
 // provides an impl of that trait, which is called `Jemalloc`) is that we
 // cannot use the sized deallocation APIs (`sdallocx`) that jemalloc provides.
 // It's unclear how much performance is lost because of this.
 //
-// As for the symbol overrides in `main` below: we're pulling in a static copy
-// of jemalloc. We need to actually reference its symbols for it to get linked.
-// The two crates we link to here, `std` and `rustc_driver`, are both dynamic
-// libraries. So we must reference jemalloc symbols one way or another, because
-// this file is the only object code in the rustc executable.
+// NOTE: Even though Cargo passes `--extern` with `tikv_jemalloc_sys`, we still need to `use` the
+// crate for the compiler to see the `#[used]`, see https://github.com/rust-lang/rust/issues/64402.
+// This is similarly required if we used a crate with `#[global_allocator]`.
 //
 // NOTE: if you are reading this comment because you want to set a custom `global_allocator` for
 // benchmarking, consider using the benchmarks in the `rustc-perf` collector suite instead:
@@ -36,43 +35,9 @@
 // to compare their performance, see
 // https://github.com/rust-lang/rust/commit/b90cfc887c31c3e7a9e6d462e2464db1fe506175#diff-43914724af6e464c1da2171e4a9b6c7e607d5bc1203fa95c0ab85be4122605ef
 // for an example of how to do so.
+#[cfg(feature = "jemalloc")]
+use tikv_jemalloc_sys as _;
 
 fn main() {
-    // See the comment at the top of this file for an explanation of this.
-    #[cfg(feature = "jemalloc")]
-    {
-        use std::os::raw::{c_int, c_void};
-
-        use tikv_jemalloc_sys as jemalloc_sys;
-
-        #[used]
-        static _F1: unsafe extern "C" fn(usize, usize) -> *mut c_void = jemalloc_sys::calloc;
-        #[used]
-        static _F2: unsafe extern "C" fn(*mut *mut c_void, usize, usize) -> c_int =
-            jemalloc_sys::posix_memalign;
-        #[used]
-        static _F3: unsafe extern "C" fn(usize, usize) -> *mut c_void = jemalloc_sys::aligned_alloc;
-        #[used]
-        static _F4: unsafe extern "C" fn(usize) -> *mut c_void = jemalloc_sys::malloc;
-        #[used]
-        static _F5: unsafe extern "C" fn(*mut c_void, usize) -> *mut c_void = jemalloc_sys::realloc;
-        #[used]
-        static _F6: unsafe extern "C" fn(*mut c_void) = jemalloc_sys::free;
-
-        // On OSX, jemalloc doesn't directly override malloc/free, but instead
-        // registers itself with the allocator's zone APIs in a ctor. However,
-        // the linker doesn't seem to consider ctors as "used" when statically
-        // linking, so we need to explicitly depend on the function.
-        #[cfg(target_os = "macos")]
-        {
-            unsafe extern "C" {
-                fn _rjem_je_zone_register();
-            }
-
-            #[used]
-            static _F7: unsafe extern "C" fn() = _rjem_je_zone_register;
-        }
-    }
-
     rustc_driver::main()
 }

compiler/rustc_ast/src/visit.rs

@@ -645,8 +645,9 @@ macro_rules! common_visitor_and_walkers {
             fn visit_fn(
                 &mut self,
                 fk: FnKind<$($lt)? $(${ignore($mut)} '_)?>,
+                _: &AttrVec,
                 _: Span,
-                _: NodeId
+                _: NodeId,
             ) -> Self::Result {
                 walk_fn(self, fk)
             }
@@ -740,6 +741,7 @@ macro_rules! common_visitor_and_walkers {
             type Ctxt;
             fn walk<$($lt,)? V: $Visitor$(<$lt>)?>(
                 &$($lt)? $($mut)? self,
+                attrs: &AttrVec,
                 span: Span,
                 id: NodeId,
                 visibility: &$($lt)? $($mut)? Visibility,
@@ -773,7 +775,7 @@ macro_rules! common_visitor_and_walkers {
         ) -> V::Result {
             let Item { attrs, id, kind, vis, span, tokens: _ } = item;
             visit_visitable!($($mut)? visitor, id, attrs, vis);
-            try_visit!(kind.walk(*span, *id, vis, ctxt, visitor));
+            try_visit!(kind.walk(attrs, *span, *id, vis, ctxt, visitor));
             visit_visitable!($($mut)? visitor, span);
             V::Result::output()
         }
@@ -799,6 +801,7 @@ macro_rules! common_visitor_and_walkers {
             type Ctxt = ();
             fn walk<$($lt,)? V: $Visitor$(<$lt>)?>(
                 &$($lt)? $($mut)? self,
+                attrs: &AttrVec,
                 span: Span,
                 id: NodeId,
                 visibility: &$($lt)? $($mut)? Visibility,
@@ -808,7 +811,7 @@ macro_rules! common_visitor_and_walkers {
                 match self {
                     ItemKind::Fn(func) => {
                         let kind = FnKind::Fn(FnCtxt::Free, visibility, &$($mut)? *func);
-                        try_visit!(vis.visit_fn(kind, span, id));
+                        try_visit!(vis.visit_fn(kind, attrs, span, id));
                     }
                     ItemKind::ExternCrate(orig_name, ident) =>
                         visit_visitable!($($mut)? vis, orig_name, ident),
@@ -856,6 +859,7 @@ macro_rules! common_visitor_and_walkers {
             type Ctxt = AssocCtxt;
             fn walk<$($lt,)? V: $Visitor$(<$lt>)?>(
                 &$($lt)? $($mut)? self,
+                attrs: &AttrVec,
                 span: Span,
                 id: NodeId,
                 visibility: &$($lt)? $($mut)? Visibility,
@@ -867,7 +871,7 @@ macro_rules! common_visitor_and_walkers {
                         visit_visitable!($($mut)? vis, item),
                     AssocItemKind::Fn(func) => {
                         let kind = FnKind::Fn(FnCtxt::Assoc(ctxt), visibility, &$($mut)? *func);
-                        try_visit!(vis.visit_fn(kind, span, id))
+                        try_visit!(vis.visit_fn(kind, attrs, span, id))
                     }
                     AssocItemKind::Type(alias) =>
                         visit_visitable!($($mut)? vis, alias),
@@ -886,6 +890,7 @@ macro_rules! common_visitor_and_walkers {
             type Ctxt = ();
             fn walk<$($lt,)? V: $Visitor$(<$lt>)?>(
                 &$($lt)? $($mut)? self,
+                attrs: &AttrVec,
                 span: Span,
                 id: NodeId,
                 visibility: &$($lt)? $($mut)? Visibility,
@@ -897,7 +902,7 @@ macro_rules! common_visitor_and_walkers {
                         visit_visitable!($($mut)? vis, item),
                     ForeignItemKind::Fn(func) => {
                         let kind = FnKind::Fn(FnCtxt::Foreign, visibility, &$($mut)?*func);
-                        try_visit!(vis.visit_fn(kind, span, id))
+                        try_visit!(vis.visit_fn(kind, attrs, span, id))
                     }
                     ForeignItemKind::TyAlias(alias) =>
                         visit_visitable!($($mut)? vis, alias),
@@ -999,7 +1004,7 @@ macro_rules! common_visitor_and_walkers {
                 }) => {
                     visit_visitable!($($mut)? vis, constness, movability, capture_clause);
                     let kind = FnKind::Closure(binder, coroutine_kind, fn_decl, body);
-                    try_visit!(vis.visit_fn(kind, *span, *id));
+                    try_visit!(vis.visit_fn(kind, attrs, *span, *id));
                     visit_visitable!($($mut)? vis, fn_decl_span, fn_arg_span);
                 }
                 ExprKind::Block(block, opt_label) =>

compiler/rustc_ast_lowering/src/expr.rs

@@ -1771,8 +1771,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let pat = self.lower_pat(pat);
         let for_span =
             self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
-        let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
-        let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
+        let for_ctxt = for_span.ctxt();
+
+        // Try to point both the head and pat spans to their position in the for loop
+        // rather than inside a macro.
+        let head_span =
+            head.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(head.span).with_ctxt(for_ctxt);
+        let pat_span =
+            pat.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(pat.span).with_ctxt(for_ctxt);
 
         let loop_hir_id = self.lower_node_id(e.id);
         let label = self.lower_label(opt_label, e.id, loop_hir_id);

compiler/rustc_ast_passes/messages.ftl

@@ -68,6 +68,10 @@ ast_passes_c_variadic_bad_extern = `...` is not supported for `extern "{$abi}"`
     .label = `extern "{$abi}"` because of this
     .help = only `extern "C"` and `extern "C-unwind"` functions may have a C variable argument list
 
+ast_passes_c_variadic_bad_naked_extern = `...` is not supported for `extern "{$abi}"` naked functions
+    .label = `extern "{$abi}"` because of this
+    .help = C-variadic function must have a compatible calling convention
+
 ast_passes_c_variadic_must_be_unsafe =
     functions with a C variable argument list must be unsafe
     .suggestion = add the `unsafe` keyword to this definition