Auto merge of #79128 - m-ou-se:rollup-lzz1dym, r=m-ou-se

Rollup of 9 pull requests

Successful merges:

 - #77939 (Ensure that the source code display is working with DOS backline)
 - #78138 (Upgrade dlmalloc to version 0.2)
 - #78967 (Make codegen tests compatible with extra inlining)
 - #79027 (Limit storage duration of inlined always live locals)
 - #79077 (document that __rust_alloc is also magic to our LLVM fork)
 - #79088 (clarify `span_label` documentation)
 - #79097 (Code block invalid html tag lint)
 - #79105 (std: Fix test `symlink_hard_link` on Windows)
 - #79107 (build-manifest: strip newline from rustc version)

Failed merges:

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

Author: bors

Cargo.lock

@@ -987,9 +987,9 @@ dependencies = [
 
 [[package]]
 name = "dlmalloc"
-version = "0.1.4"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "35055b1021724f4eb5262eb49130eebff23fc59fc5a14160e05faad8eeb36673"
+checksum = "332570860c2edf2d57914987bf9e24835425f75825086b6ba7d1e6a3e4f1f254"
 dependencies = [
  "compiler_builtins",
  "libc",

compiler/rustc_errors/src/diagnostic_builder.rs

@@ -184,16 +184,18 @@ impl<'a> DiagnosticBuilder<'a> {
         self.cancel();
     }
 
-    /// Adds a span/label to be included in the resulting snippet.
+    /// Appends a labeled span to the diagnostic.
     ///
-    /// This is pushed onto the [`MultiSpan`] that was created when the diagnostic
-    /// was first built. That means it will be shown together with the original
-    /// span/label, *not* a span added by one of the `span_{note,warn,help,suggestions}` methods.
+    /// Labels are used to convey additional context for the diagnostic's primary span. They will
+    /// be shown together with the original diagnostic's span, *not* with spans added by
+    /// `span_note`, `span_help`, etc. Therefore, if the primary span is not displayable (because
+    /// the span is `DUMMY_SP` or the source code isn't found), labels will not be displayed
+    /// either.
     ///
-    /// This span is *not* considered a ["primary span"][`MultiSpan`]; only
-    /// the `Span` supplied when creating the diagnostic is primary.
-    ///
-    /// [`MultiSpan`]: ../rustc_span/struct.MultiSpan.html
+    /// Implementation-wise, the label span is pushed onto the [`MultiSpan`] that was created when
+    /// the diagnostic was constructed. However, the label span is *not* considered a
+    /// ["primary span"][`MultiSpan`]; only the `Span` supplied when creating the diagnostic is
+    /// primary.
     pub fn span_label(&mut self, span: Span, label: impl Into<String>) -> &mut Self {
         self.0.diagnostic.span_label(span, label);
         self

compiler/rustc_middle/src/mir/mod.rs

@@ -420,7 +420,9 @@ impl<'tcx> Body<'tcx> {
     /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
     /// locals that are neither arguments nor the return place).
     #[inline]
-    pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> + ExactSizeIterator {
+    pub fn vars_and_temps_iter(
+        &self,
+    ) -> impl DoubleEndedIterator<Item = Local> + ExactSizeIterator {
         let arg_count = self.arg_count;
         let local_count = self.local_decls.len();
         (arg_count + 1..local_count).map(Local::new)

compiler/rustc_mir/src/transform/inline.rs

@@ -459,6 +459,7 @@ impl Inliner<'tcx> {
                     tcx: self.tcx,
                     callsite_span: callsite.source_info.span,
                     body_span: callee_body.span,
+                    always_live_locals: BitSet::new_filled(callee_body.local_decls.len()),
                 };
 
                 // Map all `Local`s, `SourceScope`s and `BasicBlock`s to new ones
@@ -490,6 +491,34 @@ impl Inliner<'tcx> {
                     }
                 }
 
+                // If there are any locals without storage markers, give them storage only for the
+                // duration of the call.
+                for local in callee_body.vars_and_temps_iter() {
+                    if integrator.always_live_locals.contains(local) {
+                        let new_local = integrator.map_local(local);
+                        caller_body[callsite.block].statements.push(Statement {
+                            source_info: callsite.source_info,
+                            kind: StatementKind::StorageLive(new_local),
+                        });
+                    }
+                }
+                if let Some(block) = callsite.target {
+                    // To avoid repeated O(n) insert, push any new statements to the end and rotate
+                    // the slice once.
+                    let mut n = 0;
+                    for local in callee_body.vars_and_temps_iter().rev() {
+                        if integrator.always_live_locals.contains(local) {
+                            let new_local = integrator.map_local(local);
+                            caller_body[block].statements.push(Statement {
+                                source_info: callsite.source_info,
+                                kind: StatementKind::StorageDead(new_local),
+                            });
+                            n += 1;
+                        }
+                    }
+                    caller_body[block].statements.rotate_right(n);
+                }
+
                 // Insert all of the (mapped) parts of the callee body into the caller.
                 caller_body.local_decls.extend(
                     // FIXME(eddyb) make `Range<Local>` iterable so that we can use
@@ -670,6 +699,7 @@ struct Integrator<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     callsite_span: Span,
     body_span: Span,
+    always_live_locals: BitSet<Local>,
 }
 
 impl<'a, 'tcx> Integrator<'a, 'tcx> {
@@ -759,6 +789,15 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
         }
     }
 
+    fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
+        if let StatementKind::StorageLive(local) | StatementKind::StorageDead(local) =
+            statement.kind
+        {
+            self.always_live_locals.remove(local);
+        }
+        self.super_statement(statement, location);
+    }
+
     fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, loc: Location) {
         // Don't try to modify the implicit `_0` access on return (`return` terminators are
         // replaced down below anyways).

library/alloc/src/alloc.rs

@@ -23,6 +23,8 @@ extern "Rust" {
     // (the code expanding that attribute macro generates those functions), or to call
     // the default implementations in libstd (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
     // otherwise.
+    // The rustc fork of LLVM also special-cases these function names to be able to optimize them
+    // like `malloc`, `realloc`, and `free`, respectively.
     #[rustc_allocator]
     #[rustc_allocator_nounwind]
     fn __rust_alloc(size: usize, align: usize) -> *mut u8;

library/std/Cargo.toml

@@ -36,7 +36,7 @@ features = ['read_core', 'elf', 'macho', 'pe']
 rand = "0.7"
 
 [target.'cfg(any(all(target_arch = "wasm32", not(target_os = "emscripten")), all(target_vendor = "fortanix", target_env = "sgx")))'.dependencies]
-dlmalloc = { version = "0.1", features = ['rustc-dep-of-std'] }
+dlmalloc = { version = "0.2.1", features = ['rustc-dep-of-std'] }
 
 [target.x86_64-fortanix-unknown-sgx.dependencies]
 fortanix-sgx-abi = { version = "0.3.2", features = ['rustc-dep-of-std'] }

library/std/src/fs/tests.rs

@@ -1341,6 +1341,9 @@ fn metadata_access_times() {
 #[test]
 fn symlink_hard_link() {
     let tmpdir = tmpdir();
+    if !got_symlink_permission(&tmpdir) {
+        return;
+    };
 
     // Create "file", a file.
     check!(fs::File::create(tmpdir.join("file")));

library/std/src/sys/sgx/abi/mem.rs

@@ -12,6 +12,18 @@ pub(crate) unsafe fn rel_ptr_mut<T>(offset: u64) -> *mut T {
 
 extern "C" {
     static ENCLAVE_SIZE: usize;
+    static HEAP_BASE: u64;
+    static HEAP_SIZE: usize;
+}
+
+/// Returns the base memory address of the heap
+pub(crate) fn heap_base() -> *const u8 {
+    unsafe { rel_ptr_mut(HEAP_BASE) }
+}
+
+/// Returns the size of the heap
+pub(crate) fn heap_size() -> usize {
+    unsafe { HEAP_SIZE }
 }
 
 // Do not remove inline: will result in relocation failure

library/std/src/sys/sgx/alloc.rs

@@ -1,4 +1,7 @@
 use crate::alloc::{GlobalAlloc, Layout, System};
+use crate::ptr;
+use crate::sys::sgx::abi::mem as sgx_mem;
+use core::sync::atomic::{AtomicBool, Ordering};
 
 use super::waitqueue::SpinMutex;
 
@@ -10,7 +13,48 @@ use super::waitqueue::SpinMutex;
 // dlmalloc.c from C to Rust.
 #[cfg_attr(test, linkage = "available_externally")]
 #[export_name = "_ZN16__rust_internals3std3sys3sgx5alloc8DLMALLOCE"]
-static DLMALLOC: SpinMutex<dlmalloc::Dlmalloc> = SpinMutex::new(dlmalloc::DLMALLOC_INIT);
+static DLMALLOC: SpinMutex<dlmalloc::Dlmalloc<Sgx>> =
+    SpinMutex::new(dlmalloc::Dlmalloc::new_with_allocator(Sgx {}));
+
+struct Sgx;
+
+unsafe impl dlmalloc::Allocator for Sgx {
+    /// Allocs system resources
+    fn alloc(&self, _size: usize) -> (*mut u8, usize, u32) {
+        static INIT: AtomicBool = AtomicBool::new(false);
+
+        // No ordering requirement since this function is protected by the global lock.
+        if !INIT.swap(true, Ordering::Relaxed) {
+            (sgx_mem::heap_base() as _, sgx_mem::heap_size(), 0)
+        } else {
+            (ptr::null_mut(), 0, 0)
+        }
+    }
+
+    fn remap(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize, _can_move: bool) -> *mut u8 {
+        ptr::null_mut()
+    }
+
+    fn free_part(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize) -> bool {
+        false
+    }
+
+    fn free(&self, _ptr: *mut u8, _size: usize) -> bool {
+        return false;
+    }
+
+    fn can_release_part(&self, _flags: u32) -> bool {
+        false
+    }
+
+    fn allocates_zeros(&self) -> bool {
+        false
+    }
+
+    fn page_size(&self) -> usize {
+        0x1000
+    }
+}
 
 #[stable(feature = "alloc_system_type", since = "1.28.0")]
 unsafe impl GlobalAlloc for System {

library/std/src/sys/wasm/alloc.rs

@@ -18,7 +18,7 @@
 
 use crate::alloc::{GlobalAlloc, Layout, System};
 
-static mut DLMALLOC: dlmalloc::Dlmalloc = dlmalloc::DLMALLOC_INIT;
+static mut DLMALLOC: dlmalloc::Dlmalloc = dlmalloc::Dlmalloc::new();
 
 #[stable(feature = "alloc_system_type", since = "1.28.0")]
 unsafe impl GlobalAlloc for System {