Auto merge of rust-lang#105703 - matthiaskrgr:rollup-tfpeam2, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#105399 (Use more LFS functions.)
 - rust-lang#105578 (Fix transmutes between pointers in different address spaces (e.g. fn ptrs on AVR))
 - rust-lang#105598 (explain mem::forget(env_lock) in fork/exec)
 - rust-lang#105624 (Fix unsoundness in bootstrap cache code)
 - rust-lang#105630 (Add a test for rust-lang#92481)
 - rust-lang#105684 (Improve rustdoc markdown variable naming)
 - rust-lang#105697 (Remove fee1-dead from reviewers)

Failed merges:

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

Author: bors

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1802,15 +1802,20 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         match (src.layout.abi, dst.layout.abi) {
             (abi::Abi::Scalar(src_scalar), abi::Abi::Scalar(dst_scalar)) => {
                 // HACK(eddyb) LLVM doesn't like `bitcast`s between pointers and non-pointers.
-                if (src_scalar.primitive() == abi::Pointer)
-                    == (dst_scalar.primitive() == abi::Pointer)
-                {
+                let src_is_ptr = src_scalar.primitive() == abi::Pointer;
+                let dst_is_ptr = dst_scalar.primitive() == abi::Pointer;
+                if src_is_ptr == dst_is_ptr {
                     assert_eq!(src.layout.size, dst.layout.size);
 
                     // NOTE(eddyb) the `from_immediate` and `to_immediate_scalar`
                     // conversions allow handling `bool`s the same as `u8`s.
                     let src = bx.from_immediate(src.immediate());
-                    let src_as_dst = bx.bitcast(src, bx.backend_type(dst.layout));
+                    // LLVM also doesn't like `bitcast`s between pointers in different address spaces.
+                    let src_as_dst = if src_is_ptr {
+                        bx.pointercast(src, bx.backend_type(dst.layout))
+                    } else {
+                        bx.bitcast(src, bx.backend_type(dst.layout))
+                    };
                     Immediate(bx.to_immediate_scalar(src_as_dst, dst_scalar)).store(bx, dst);
                     return;
                 }

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

@@ -1759,8 +1759,13 @@ mod remove_dir_impl {
     use crate::sys::common::small_c_string::run_path_with_cstr;
     use crate::sys::{cvt, cvt_r};
 
-    #[cfg(not(all(target_os = "macos", not(target_arch = "aarch64")),))]
+    #[cfg(not(any(
+        target_os = "linux",
+        all(target_os = "macos", not(target_arch = "aarch64"))
+    )))]
     use libc::{fdopendir, openat, unlinkat};
+    #[cfg(target_os = "linux")]
+    use libc::{fdopendir, openat64 as openat, unlinkat};
     #[cfg(all(target_os = "macos", not(target_arch = "aarch64")))]
     use macos_weak::{fdopendir, openat, unlinkat};
 

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

@@ -61,6 +61,10 @@ use crate::ptr;
 use crate::sync::atomic::{AtomicBool, AtomicU8, Ordering};
 use crate::sys::cvt;
 use crate::sys::weak::syscall;
+#[cfg(not(target_os = "linux"))]
+use libc::sendfile as sendfile64;
+#[cfg(target_os = "linux")]
+use libc::sendfile64;
 use libc::{EBADF, EINVAL, ENOSYS, EOPNOTSUPP, EOVERFLOW, EPERM, EXDEV};
 
 #[cfg(test)]
@@ -647,7 +651,7 @@ fn sendfile_splice(mode: SpliceMode, reader: RawFd, writer: RawFd, len: u64) ->
 
         let result = match mode {
             SpliceMode::Sendfile => {
-                cvt(unsafe { libc::sendfile(writer, reader, ptr::null_mut(), chunk_size) })
+                cvt(unsafe { sendfile64(writer, reader, ptr::null_mut(), chunk_size) })
             }
             SpliceMode::Splice => cvt(unsafe {
                 splice(reader, ptr::null_mut(), writer, ptr::null_mut(), chunk_size, 0)

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

@@ -95,6 +95,10 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
         )))]
         'poll: {
             use crate::sys::os::errno;
+            #[cfg(not(target_os = "linux"))]
+            use libc::open as open64;
+            #[cfg(target_os = "linux")]
+            use libc::open64;
             let pfds: &mut [_] = &mut [
                 libc::pollfd { fd: 0, events: 0, revents: 0 },
                 libc::pollfd { fd: 1, events: 0, revents: 0 },
@@ -116,7 +120,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
                 if pfd.revents & libc::POLLNVAL == 0 {
                     continue;
                 }
-                if libc::open("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
+                if open64("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
                     // If the stream is closed but we failed to reopen it, abort the
                     // process. Otherwise we wouldn't preserve the safety of
                     // operations on the corresponding Rust object Stdin, Stdout, or
@@ -139,9 +143,13 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
         )))]
         {
             use crate::sys::os::errno;
+            #[cfg(not(target_os = "linux"))]
+            use libc::open as open64;
+            #[cfg(target_os = "linux")]
+            use libc::open64;
             for fd in 0..3 {
                 if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
-                    if libc::open("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
+                    if open64("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
                         // If the stream is closed but we failed to reopen it, abort the
                         // process. Otherwise we wouldn't preserve the safety of
                         // operations on the corresponding Rust object Stdin, Stdout, or

library/std/src/sys/unix/process/process_unix.rs

@@ -66,14 +66,15 @@ impl Command {
         //
         // Note that as soon as we're done with the fork there's no need to hold
         // a lock any more because the parent won't do anything and the child is
-        // in its own process. Thus the parent drops the lock guard while the child
-        // forgets it to avoid unlocking it on a new thread, which would be invalid.
+        // in its own process. Thus the parent drops the lock guard immediately.
+        // The child calls `mem::forget` to leak the lock, which is crucial because
+        // releasing a lock is not async-signal-safe.
         let env_lock = sys::os::env_read_lock();
         let (pid, pidfd) = unsafe { self.do_fork()? };
 
         if pid == 0 {
             crate::panic::always_abort();
-            mem::forget(env_lock);
+            mem::forget(env_lock); // avoid non-async-signal-safe unlocking
             drop(input);
             let Err(err) = unsafe { self.do_exec(theirs, envp.as_ref()) };
             let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;

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

@@ -45,7 +45,10 @@ mod imp {
     use crate::thread;
 
     use libc::MAP_FAILED;
-    use libc::{mmap, munmap};
+    #[cfg(not(target_os = "linux"))]
+    use libc::{mmap as mmap64, munmap};
+    #[cfg(target_os = "linux")]
+    use libc::{mmap64, munmap};
     use libc::{sigaction, sighandler_t, SA_ONSTACK, SA_SIGINFO, SIGBUS, SIG_DFL};
     use libc::{sigaltstack, SIGSTKSZ, SS_DISABLE};
     use libc::{MAP_ANON, MAP_PRIVATE, PROT_NONE, PROT_READ, PROT_WRITE, SIGSEGV};
@@ -135,7 +138,7 @@ mod imp {
         #[cfg(not(any(target_os = "openbsd", target_os = "netbsd", target_os = "linux",)))]
         let flags = MAP_PRIVATE | MAP_ANON;
         let stackp =
-            mmap(ptr::null_mut(), SIGSTKSZ + page_size(), PROT_READ | PROT_WRITE, flags, -1, 0);
+            mmap64(ptr::null_mut(), SIGSTKSZ + page_size(), PROT_READ | PROT_WRITE, flags, -1, 0);
         if stackp == MAP_FAILED {
             panic!("failed to allocate an alternative stack: {}", io::Error::last_os_error());
         }

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

@@ -653,7 +653,10 @@ pub mod guard {
 ))]
 #[cfg_attr(test, allow(dead_code))]
 pub mod guard {
-    use libc::{mmap, mprotect};
+    #[cfg(not(target_os = "linux"))]
+    use libc::{mmap as mmap64, mprotect};
+    #[cfg(target_os = "linux")]
+    use libc::{mmap64, mprotect};
     use libc::{MAP_ANON, MAP_FAILED, MAP_FIXED, MAP_PRIVATE, PROT_NONE, PROT_READ, PROT_WRITE};
 
     use crate::io;
@@ -803,7 +806,7 @@ pub mod guard {
             // read/write permissions and only then mprotect() it to
             // no permissions at all. See issue #50313.
             let stackptr = get_stack_start_aligned()?;
-            let result = mmap(
+            let result = mmap64(
                 stackptr,
                 page_size,
                 PROT_READ | PROT_WRITE,

src/bootstrap/cache.rs

@@ -89,16 +89,16 @@ impl<T: Internable + Hash> Hash for Interned<T> {
 
 impl<T: Internable + Deref> Deref for Interned<T> {
     type Target = T::Target;
-    fn deref(&self) -> &'static Self::Target {
+    fn deref(&self) -> &Self::Target {
         let l = T::intern_cache().lock().unwrap();
-        unsafe { mem::transmute::<&Self::Target, &'static Self::Target>(l.get(*self)) }
+        unsafe { mem::transmute::<&Self::Target, &Self::Target>(l.get(*self)) }
     }
 }
 
 impl<T: Internable + AsRef<U>, U: ?Sized> AsRef<U> for Interned<T> {
-    fn as_ref(&self) -> &'static U {
+    fn as_ref(&self) -> &U {
         let l = T::intern_cache().lock().unwrap();
-        unsafe { mem::transmute::<&U, &'static U>(l.get(*self).as_ref()) }
+        unsafe { mem::transmute::<&U, &U>(l.get(*self).as_ref()) }
     }
 }
 

src/librustdoc/html/markdown.rs

@@ -236,12 +236,12 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
             return event;
         };
 
-        let mut origtext = String::new();
+        let mut original_text = String::new();
         for event in &mut self.inner {
             match event {
                 Event::End(Tag::CodeBlock(..)) => break,
                 Event::Text(ref s) => {
-                    origtext.push_str(s);
+                    original_text.push_str(s);
                 }
                 _ => {}
             }
@@ -258,7 +258,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                                  <pre class=\"language-{}\"><code>{}</code></pre>\
                              </div>",
                             lang,
-                            Escape(&origtext),
+                            Escape(&original_text),
                         )
                         .into(),
                     ));
@@ -268,7 +268,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
             CodeBlockKind::Indented => Default::default(),
         };
 
-        let lines = origtext.lines().filter_map(|l| map_line(l).for_html());
+        let lines = original_text.lines().filter_map(|l| map_line(l).for_html());
         let text = lines.intersperse("\n".into()).collect::<String>();
 
         compile_fail = parse_result.compile_fail;
@@ -285,7 +285,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
             if url.is_empty() {
                 return None;
             }
-            let test = origtext
+            let test = original_text
                 .lines()
                 .map(|l| map_line(l).for_code())
                 .intersperse("\n".into())

src/test/codegen/avr/avr-func-addrspace.rs

@@ -9,7 +9,7 @@
 // It also validates that functions can be called through function pointers
 // through traits.
 
-#![feature(no_core, lang_items, unboxed_closures, arbitrary_self_types)]
+#![feature(no_core, lang_items, intrinsics, unboxed_closures, arbitrary_self_types)]
 #![crate_type = "lib"]
 #![no_core]
 
@@ -49,6 +49,10 @@ pub trait Fn<Args: Tuple>: FnOnce<Args> {
     extern "rust-call" fn call(&self, args: Args) -> Self::Output;
 }
 
+extern "rust-intrinsic" {
+    pub fn transmute<Src, Dst>(src: Src) -> Dst;
+}
+
 pub static mut STORAGE_FOO: fn(&usize, &mut u32) -> Result<(), ()> = arbitrary_black_box;
 pub static mut STORAGE_BAR: u32 = 12;
 
@@ -87,3 +91,21 @@ pub extern "C" fn test() {
         STORAGE_FOO(&1, &mut buf);
     }
 }
+
+// Validate that we can codegen transmutes between data ptrs and fn ptrs.
+
+// CHECK: define{{.+}}{{void \(\) addrspace\(1\)\*|ptr addrspace\(1\)}} @transmute_data_ptr_to_fn({{\{\}\*|ptr}}{{.*}} %x)
+#[no_mangle]
+pub unsafe fn transmute_data_ptr_to_fn(x: *const ()) -> fn() {
+    // It doesn't matter precisely how this is codegenned (through memory or an addrspacecast),
+    // as long as it doesn't cause a verifier error by using `bitcast`.
+    transmute(x)
+}
+
+// CHECK: define{{.+}}{{\{\}\*|ptr}} @transmute_fn_ptr_to_data({{void \(\) addrspace\(1\)\*|ptr addrspace\(1\)}}{{.*}} %x)
+#[no_mangle]
+pub unsafe fn transmute_fn_ptr_to_data(x: fn()) -> *const () {
+    // It doesn't matter precisely how this is codegenned (through memory or an addrspacecast),
+    // as long as it doesn't cause a verifier error by using `bitcast`.
+    transmute(x)
+}