emscripten: Upgrade emsdk to 3.1.68

In line with commit rust-lang/rust@2c38ecf.

While we're here, make the changes in commit 63b0d67 unconditional,
which means that Emscripten 3.1.42 (released at 2023/06/23) is the
minimum required version for Rust, assuming no breaking ABI changes
occurred after that version.

Author: kleisauke

build.rs

@@ -6,7 +6,6 @@ use std::str;
 // need to know all the possible cfgs that this script will set. If you need to set another cfg
 // make sure to add it to this list as well.
 const ALLOWED_CFGS: &'static [&'static str] = &[
-    "emscripten_new_stat_abi",
     "espidf_time64",
     "freebsd10",
     "freebsd11",
@@ -67,12 +66,6 @@ fn main() {
         _ => set_cfg("freebsd15"),
     }
 
-    match emcc_version_code() {
-        Some(v) if (v >= 30142) => set_cfg("emscripten_new_stat_abi"),
-        // Non-Emscripten or version < 3.1.42.
-        Some(_) | None => (),
-    }
-
     // On CI: deny all warnings
     if libc_ci {
         set_cfg("libc_deny_warnings");
@@ -212,28 +205,6 @@ fn which_freebsd() -> Option<i32> {
     }
 }
 
-fn emcc_version_code() -> Option<u64> {
-    let output = std::process::Command::new("emcc")
-        .arg("-dumpversion")
-        .output()
-        .ok()?;
-    if !output.status.success() {
-        return None;
-    }
-
-    let version = String::from_utf8(output.stdout).ok()?;
-
-    // Some Emscripten versions come with `-git` attached, so split the
-    // version string also on the `-` char.
-    let mut pieces = version.trim().split(['.', '-']);
-
-    let major = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
-    let minor = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
-    let patch = pieces.next().and_then(|x| x.parse().ok()).unwrap_or(0);
-
-    Some(major * 10000 + minor * 100 + patch)
-}
-
 fn set_cfg(cfg: &str) {
     if !ALLOWED_CFGS.contains(&cfg) {
         panic!("trying to set cfg {}, but it is not in ALLOWED_CFGS", cfg);

ci/emscripten.sh

@@ -2,9 +2,9 @@
 
 set -ex
 
-# FIXME: 3.1.21 removed a lot of header files (https://github.com/emscripten-core/emscripten/pull/17704).
-#        We have to tweak libc-test (and deprecate unsupported items, maybe) when updating emsdk.
-EMSDK_VERSION=3.1.20
+# Note: keep in sync with:
+# https://github.com/rust-lang/rust/blob/master/src/ci/docker/scripts/emscripten.sh
+EMSDK_VERSION=3.1.68
 
 git clone https://github.com/emscripten-core/emsdk.git /emsdk-portable
 cd /emsdk-portable

libc-test/build.rs

@@ -2703,7 +2703,6 @@ fn test_emscripten(target: &str) {
     cfg.define("_GNU_SOURCE", None); // FIXME: ??
 
     headers! { cfg:
-               "aio.h",
                "ctype.h",
                "dirent.h",
                "dlfcn.h",
@@ -2743,32 +2742,21 @@ fn test_emscripten(target: &str) {
                "stdio.h",
                "stdlib.h",
                "string.h",
-               "sys/epoll.h",
-               "sys/eventfd.h",
                "sys/file.h",
                "sys/ioctl.h",
                "sys/ipc.h",
                "sys/mman.h",
                "sys/mount.h",
                "sys/msg.h",
-               "sys/personality.h",
-               "sys/prctl.h",
-               "sys/ptrace.h",
-               "sys/quota.h",
-               "sys/reboot.h",
                "sys/resource.h",
                "sys/sem.h",
                "sys/shm.h",
-               "sys/signalfd.h",
                "sys/socket.h",
                "sys/stat.h",
                "sys/statvfs.h",
-               "sys/swap.h",
                "sys/syscall.h",
-               "sys/sysctl.h",
                "sys/sysinfo.h",
                "sys/time.h",
-               "sys/timerfd.h",
                "sys/times.h",
                "sys/types.h",
                "sys/uio.h",
@@ -2794,9 +2782,7 @@ fn test_emscripten(target: &str) {
             // Just pass all these through, no need for a "struct" prefix
             "FILE" | "fd_set" | "Dl_info" | "DIR" => ty.to_string(),
 
-            "os_unfair_lock" => "struct os_unfair_lock_s".to_string(),
-
-            // LFS64 types have been removed in Emscripten 3.1.44+
+            // LFS64 types have been removed in Emscripten 3.1.44
             // https://github.com/emscripten-core/emscripten/pull/19812
             "off64_t" => "off_t".to_string(),
 
@@ -2820,7 +2806,7 @@ fn test_emscripten(target: &str) {
             s if s.ends_with("_nsec") && struct_.starts_with("stat") => {
                 s.replace("e_nsec", ".tv_nsec")
             }
-            // FIXME: appears that `epoll_event.data` is an union
+            // Rust struct uses raw u64, rather than union
             "u64" if struct_ == "epoll_event" => "data.u64".to_string(),
             s => s.to_string(),
         }
@@ -2832,10 +2818,11 @@ fn test_emscripten(target: &str) {
             // FIXME: is this necessary?
             "sighandler_t" => true,
 
-            // FIXME: The size has been changed due to musl's time64
-            "time_t" => true,
+            // No epoll support
+            // https://github.com/emscripten-core/emscripten/issues/5033
+            ty if ty.starts_with("epoll") => true,
 
-            // LFS64 types have been removed in Emscripten 3.1.44+
+            // LFS64 types have been removed in Emscripten 3.1.44
             // https://github.com/emscripten-core/emscripten/pull/19812
             t => t.ends_with("64") || t.ends_with("64_t"),
         }
@@ -2844,29 +2831,19 @@ fn test_emscripten(target: &str) {
     cfg.skip_struct(move |ty| {
         match ty {
             // This is actually a union, not a struct
-            // FIXME: is this necessary?
             "sigval" => true,
 
-            // FIXME: It was removed in
-            // emscripten-core/emscripten@953e414
-            "pthread_mutexattr_t" => true,
-
             // FIXME: Investigate why the test fails.
             // Skip for now to unblock CI.
             "pthread_condattr_t" => true,
+            "pthread_mutexattr_t" => true,
 
-            // FIXME: The size has been changed when upgraded to musl 1.2.2
-            "pthread_mutex_t" => true,
-
-            // FIXME: Lowered from 16 to 8 bytes in
-            // llvm/llvm-project@d1a96e9
-            "max_align_t" => true,
-
-            // FIXME: The size has been changed due to time64
-            "utimbuf" | "timeval" | "timespec" | "rusage" | "itimerval" | "sched_param"
-            | "stat" | "stat64" | "shmid_ds" | "msqid_ds" => true,
+            // No epoll support
+            // https://github.com/emscripten-core/emscripten/issues/5033
+            ty if ty.starts_with("epoll") => true,
+            ty if ty.starts_with("signalfd") => true,
 
-            // LFS64 types have been removed in Emscripten 3.1.44+
+            // LFS64 types have been removed in Emscripten 3.1.44
             // https://github.com/emscripten-core/emscripten/pull/19812
             ty => ty.ends_with("64") || ty.ends_with("64_t"),
         }
@@ -2875,12 +2852,9 @@ fn test_emscripten(target: &str) {
     cfg.skip_fn(move |name| {
         match name {
             // Emscripten does not support fork/exec/wait or any kind of multi-process support
-            // https://github.com/emscripten-core/emscripten/blob/3.1.30/tools/system_libs.py#L973
+            // https://github.com/emscripten-core/emscripten/blob/3.1.68/tools/system_libs.py#L1100
             "execv" | "execve" | "execvp" | "execvpe" | "fexecve" | "wait4" => true,
 
-            // FIXME: Remove after emscripten-core/emscripten#18492 is released (> 3.1.30).
-            "clearenv" => true,
-
             _ => false,
         }
     });
@@ -2894,23 +2868,35 @@ fn test_emscripten(target: &str) {
             // FIXME: emscripten uses different constants to constructs these
             n if n.contains("__SIZEOF_PTHREAD") => true,
 
-            // FIXME: `SYS_gettid` was removed in
-            // emscripten-core/emscripten@6d6474e
+            // No epoll support
+            // https://github.com/emscripten-core/emscripten/issues/5033
+            n if n.starts_with("EPOLL") => true,
+
+            // No ptrace.h
+            // https://github.com/emscripten-core/emscripten/pull/17704
+            n if n.starts_with("PTRACE_") => true,
+
+            // No quota.h
+            // https://github.com/emscripten-core/emscripten/pull/17704
+            n if n.starts_with("QIF_") => true,
+
+            // `SYS_gettid` was removed in Emscripten v1.39.9
+            // https://github.com/emscripten-core/emscripten/pull/10439
             "SYS_gettid" => true,
 
-            // FIXME: These values have been changed
-            | "POSIX_MADV_DONTNEED" // to 4
-            | "RLIMIT_NLIMITS" // to 16
-            | "RLIM_NLIMITS" // to 16
-            | "IPPROTO_MAX" // to 263
-            | "F_GETLK" // to 5
-            | "F_SETLK" // to 6
-            | "F_SETLKW" // to 7
-            | "O_TMPFILE" // to 65
-            | "SIG_IGN" // -1
-                => true,
+            "ADDR_NO_RANDOMIZE" | "MMAP_PAGE_ZERO" | "ADDR_COMPAT_LAYOUT" | "READ_IMPLIES_EXEC"
+            | "ADDR_LIMIT_32BIT" | "SHORT_INODE" | "WHOLE_SECONDS" | "STICKY_TIMEOUTS"
+            | "ADDR_LIMIT_3GB" => true,
+
+            "USRQUOTA" | "GRPQUOTA" => true,
 
-            // LFS64 types have been removed in Emscripten 3.1.44+
+            "Q_GETFMT" | "Q_GETINFO" | "Q_SETINFO" | "Q_SYNC" | "Q_QUOTAON" | "Q_QUOTAOFF"
+            | "Q_GETQUOTA" | "Q_SETQUOTA" => true,
+
+            // FIXME: https://github.com/emscripten-core/emscripten/pull/14883
+            "SIG_IGN" => true,
+
+            // LFS64 types have been removed in Emscripten 3.1.44
             // https://github.com/emscripten-core/emscripten/pull/19812
             n if n.starts_with("RLIM64") => true,
 
@@ -2920,38 +2906,19 @@ fn test_emscripten(target: &str) {
 
     cfg.skip_field_type(move |struct_, field| {
         // This is a weird union, don't check the type.
-        // FIXME: is this necessary?
         (struct_ == "ifaddrs" && field == "ifa_ifu") ||
         // sighandler_t type is super weird
-        // FIXME: is this necessary?
         (struct_ == "sigaction" && field == "sa_sigaction") ||
         // sigval is actually a union, but we pretend it's a struct
-        // FIXME: is this necessary?
-        (struct_ == "sigevent" && field == "sigev_value") ||
-        // aio_buf is "volatile void*" and Rust doesn't understand volatile
-        // FIXME: is this necessary?
-        (struct_ == "aiocb" && field == "aio_buf")
+        (struct_ == "sigevent" && field == "sigev_value")
     });
 
     cfg.skip_field(move |struct_, field| {
         // this is actually a union on linux, so we can't represent it well and
         // just insert some padding.
-        // FIXME: is this necessary?
         (struct_ == "siginfo_t" && field == "_pad") ||
         // musl names this __dummy1 but it's still there
-        // FIXME: is this necessary?
         (struct_ == "glob_t" && field == "gl_flags") ||
-        // musl seems to define this as an *anonymous* bitfield
-        // FIXME: is this necessary?
-        (struct_ == "statvfs" && field == "__f_unused") ||
-        // sigev_notify_thread_id is actually part of a sigev_un union
-        (struct_ == "sigevent" && field == "sigev_notify_thread_id") ||
-        // signalfd had SIGSYS fields added in Linux 4.18, but no libc release has them yet.
-        (struct_ == "signalfd_siginfo" && (field == "ssi_addr_lsb" ||
-                                           field == "_pad2" ||
-                                           field == "ssi_syscall" ||
-                                           field == "ssi_call_addr" ||
-                                           field == "ssi_arch")) ||
         // FIXME: After musl 1.1.24, it have only one field `sched_priority`,
         // while other fields become reserved.
         (struct_ == "sched_param" && [
@@ -2962,7 +2929,6 @@ fn test_emscripten(target: &str) {
         ].contains(&field))
     });
 
-    // FIXME: test linux like
     cfg.generate("../src/lib.rs", "main.rs");
 }
 

src/unix/linux_like/emscripten/align.rs

@@ -37,10 +37,12 @@ macro_rules! expand_align {
                 size: [u8; ::__SIZEOF_PTHREAD_COND_T],
             }
 
+            // Lowered from 16 to 8 bytes in
+            // https://github.com/llvm/llvm-project/commit/d1a96e906cc03a95cfd41a1f22bdda92651250c7
             #[allow(missing_debug_implementations)]
-            #[repr(align(16))]
+            #[repr(align(8))]
             pub struct max_align_t {
-                priv_: [f64; 4]
+                priv_: [f64; 3]
             }
 
         }