Auto merge of #74576 - myfreeweb:freebsd-sanitizers, r=oli-obk

Add sanitizer support on FreeBSD

Restarting #47337. Everything is better now, no more weird llvm problems, well not everything:

Unfortunately, the sanitizers don't have proper support for versioned symbols (google/sanitizers#628), so `libc`'s usage of `stat@FBSD_1.0` and so on explodes, e.g. in calling `std::fs::metadata`.

Building std (now easy thanks to cargo `-Zbuild-std`) and libc with `freebsd12/13` config via the `LIBC_CI=1` env variable is a good workaround…

```
LIBC_CI=1 RUSTFLAGS="-Z sanitizer=address" cargo +san-test -Zbuild-std run --target x86_64-unknown-freebsd --verbose
```

…*except* std won't build because there's no `st_lspare` in the ino64 version of the struct, so an std patch is required:

```diff
--- i/src/libstd/os/freebsd/fs.rs
+++ w/src/libstd/os/freebsd/fs.rs
@@ -66,8 +66,6 @@ pub trait MetadataExt {
     fn st_flags(&self) -> u32;
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_gen(&self) -> u32;
-    #[stable(feature = "metadata_ext2", since = "1.8.0")]
-    fn st_lspare(&self) -> u32;
 }

 #[stable(feature = "metadata_ext", since = "1.1.0")]
@@ -136,7 +134,4 @@ impl MetadataExt for Metadata {
     fn st_flags(&self) -> u32 {
         self.as_inner().as_inner().st_flags as u32
     }
-    fn st_lspare(&self) -> u32 {
-        self.as_inner().as_inner().st_lspare as u32
-    }
 }
```

I guess std could like.. detect that `libc` isn't built for the old ABI, and replace the implementation of `st_lspare` with a panic?

Author: bors

library/std/build.rs

@@ -16,6 +16,9 @@ fn main() {
     } else if target.contains("freebsd") {
         println!("cargo:rustc-link-lib=execinfo");
         println!("cargo:rustc-link-lib=pthread");
+        if env::var("RUST_STD_FREEBSD_12_ABI").is_ok() {
+            println!("cargo:rustc-cfg=freebsd12");
+        }
     } else if target.contains("netbsd") {
         println!("cargo:rustc-link-lib=pthread");
         println!("cargo:rustc-link-lib=rt");

library/std/src/os/freebsd/fs.rs

@@ -74,7 +74,14 @@ pub trait MetadataExt {
 impl MetadataExt for Metadata {
     #[allow(deprecated)]
     fn as_raw_stat(&self) -> &raw::stat {
-        unsafe { &*(self.as_inner().as_inner() as *const libc::stat as *const raw::stat) }
+        // The methods below use libc::stat, so they work fine when libc is built with FreeBSD 12 ABI.
+        // This method would just return nonsense.
+        #[cfg(freebsd12)]
+        panic!("as_raw_stat not supported with FreeBSD 12 ABI");
+        #[cfg(not(freebsd12))]
+        unsafe {
+            &*(self.as_inner().as_inner() as *const libc::stat as *const raw::stat)
+        }
     }
     fn st_dev(&self) -> u64 {
         self.as_inner().as_inner().st_dev as u64
@@ -136,6 +143,11 @@ impl MetadataExt for Metadata {
     fn st_flags(&self) -> u32 {
         self.as_inner().as_inner().st_flags as u32
     }
+    #[cfg(freebsd12)]
+    fn st_lspare(&self) -> u32 {
+        panic!("st_lspare not supported with FreeBSD 12 ABI");
+    }
+    #[cfg(not(freebsd12))]
     fn st_lspare(&self) -> u32 {
         self.as_inner().as_inner().st_lspare as u32
     }

src/bootstrap/native.rs

@@ -794,6 +794,7 @@ fn supported_sanitizers(
         }
         "x86_64-apple-darwin" => darwin_libs("osx", &["asan", "lsan", "tsan"]),
         "x86_64-fuchsia" => common_libs("fuchsia", "x86_64", &["asan"]),
+        "x86_64-unknown-freebsd" => common_libs("freebsd", "x86_64", &["asan", "msan", "tsan"]),
         "x86_64-unknown-linux-gnu" => {
             common_libs("linux", "x86_64", &["asan", "lsan", "msan", "tsan"])
         }

src/ci/docker/host-x86_64/dist-x86_64-freebsd/Dockerfile

@@ -29,5 +29,5 @@ ENV \
 
 ENV HOSTS=x86_64-unknown-freebsd
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --enable-profiler --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --enable-profiler --enable-sanitizers --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/librustc_codegen_ssa/back/link.rs

@@ -822,6 +822,7 @@ fn link_sanitizer_runtime(sess: &Session, linker: &mut dyn Linker, name: &str) {
         "aarch64-fuchsia"
         | "aarch64-unknown-linux-gnu"
         | "x86_64-fuchsia"
+        | "x86_64-unknown-freebsd"
         | "x86_64-unknown-linux-gnu" => {
             let filename = format!("librustc{}_rt.{}.a", channel, name);
             let path = default_tlib.join(&filename);

src/librustc_session/session.rs

@@ -1453,14 +1453,19 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
         "aarch64-unknown-linux-gnu",
         "x86_64-apple-darwin",
         "x86_64-fuchsia",
+        "x86_64-unknown-freebsd",
         "x86_64-unknown-linux-gnu",
     ];
     const LSAN_SUPPORTED_TARGETS: &[&str] =
         &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
     const MSAN_SUPPORTED_TARGETS: &[&str] =
-        &["aarch64-unknown-linux-gnu", "x86_64-unknown-linux-gnu"];
-    const TSAN_SUPPORTED_TARGETS: &[&str] =
-        &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+        &["aarch64-unknown-linux-gnu", "x86_64-unknown-freebsd", "x86_64-unknown-linux-gnu"];
+    const TSAN_SUPPORTED_TARGETS: &[&str] = &[
+        "aarch64-unknown-linux-gnu",
+        "x86_64-apple-darwin",
+        "x86_64-unknown-freebsd",
+        "x86_64-unknown-linux-gnu",
+    ];
 
     // Sanitizers can only be used on some tested platforms.
     for s in sess.opts.debugging_opts.sanitizer {

src/tools/compiletest/src/util.rs

@@ -87,17 +87,22 @@ pub const ASAN_SUPPORTED_TARGETS: &'static [&'static str] = &[
     "aarch64-unknown-linux-gnu",
     "x86_64-apple-darwin",
     "x86_64-fuchsia",
+    "x86_64-unknown-freebsd",
     "x86_64-unknown-linux-gnu",
 ];
 
 pub const LSAN_SUPPORTED_TARGETS: &'static [&'static str] =
     &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
 
 pub const MSAN_SUPPORTED_TARGETS: &'static [&'static str] =
-    &["aarch64-unknown-linux-gnu", "x86_64-unknown-linux-gnu"];
+    &["aarch64-unknown-linux-gnu", "x86_64-unknown-freebsd", "x86_64-unknown-linux-gnu"];
 
-pub const TSAN_SUPPORTED_TARGETS: &'static [&'static str] =
-    &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+pub const TSAN_SUPPORTED_TARGETS: &'static [&'static str] = &[
+    "aarch64-unknown-linux-gnu",
+    "x86_64-apple-darwin",
+    "x86_64-unknown-freebsd",
+    "x86_64-unknown-linux-gnu",
+];
 
 const BIG_ENDIAN: &'static [&'static str] = &[
     "armebv7r",