Rollup merge of rust-lang#115049 - RalfJung:miri, r=RalfJung

update Miri

r? `@ghost`

Author: matthiaskrgr

Cargo.lock

@@ -2334,6 +2334,7 @@ dependencies = [
  "rand",
  "regex",
  "rustc_version",
+ "serde",
  "smallvec",
  "ui_test",
 ]

src/tools/miri/CONTRIBUTING.md

@@ -165,16 +165,17 @@ to `.vscode/settings.json` in your local Miri clone:
 {
     "rust-analyzer.rustc.source": "discover",
     "rust-analyzer.linkedProjects": [
-        "./Cargo.toml",
-        "./cargo-miri/Cargo.toml"
+        "Cargo.toml",
+        "cargo-miri/Cargo.toml",
+        "miri-script/Cargo.toml",
     ],
-    "rust-analyzer.checkOnSave.overrideCommand": [
+    "rust-analyzer.check.overrideCommand": [
         "env",
         "MIRI_AUTO_OPS=no",
         "./miri",
         "cargo",
         "clippy", // make this `check` when working with a locally built rustc
-        "--message-format=json"
+        "--message-format=json",
     ],
     // Contrary to what the name suggests, this also affects proc macros.
     "rust-analyzer.cargo.buildScripts.overrideCommand": [

src/tools/miri/Cargo.lock

@@ -443,6 +443,7 @@ dependencies = [
  "rand",
  "regex",
  "rustc_version",
+ "serde",
  "smallvec",
  "ui_test",
 ]

src/tools/miri/Cargo.toml

@@ -41,6 +41,8 @@ rustc_version = "0.4"
 # Features chosen to match those required by env_logger, to avoid rebuilds
 regex = { version = "1.5.5", default-features = false, features = ["perf", "std"] }
 lazy_static = "1.4.0"
+# Pin a version of serde without intransparent unreproducible binary blobs.
+serde = { version = "1.0, < 1.0.172", features = ["derive"] }
 
 [package.metadata.rust-analyzer]
 # This crate uses #[feature(rustc_private)].

src/tools/miri/README.md

@@ -458,8 +458,8 @@ Some native rustc `-Z` flags are also very relevant for Miri:
 Moreover, Miri recognizes some environment variables:
 
 * `MIRI_AUTO_OPS` indicates whether the automatic execution of rustfmt, clippy and toolchain setup
-  should be skipped. If it is set to any value, they are skipped. This is used for avoiding infinite
-  recursion in `./miri` and to allow automated IDE actions to avoid the auto ops.
+  should be skipped. If it is set to `no`, they are skipped. This is used to allow automated IDE
+  actions to avoid the auto ops.
 * `MIRI_LOG`, `MIRI_BACKTRACE` control logging and backtrace printing during
   Miri executions, also [see "Testing the Miri driver" in `CONTRIBUTING.md`][testing-miri].
 * `MIRIFLAGS` (recognized by `cargo miri` and the test suite) defines extra

src/tools/miri/cargo-miri/Cargo.toml

@@ -22,7 +22,8 @@ rustc-build-sysroot = "0.4.1"
 
 # Enable some feature flags that dev-dependencies need but dependencies
 # do not.  This makes `./miri install` after `./miri build` faster.
-serde = { version = "*", features = ["derive"] }
+# Pin a version of serde without intransparent unreproducible binary blobs.
+serde = { version = "1.0, < 1.0.172", features = ["derive"] }
 
 [build-dependencies]
 rustc_tools_util = "0.3"

src/tools/miri/miri-script/src/commands.rs

@@ -57,6 +57,10 @@ impl MiriEnv {
 
 impl Command {
     fn auto_actions() -> Result<()> {
+        if env::var_os("MIRI_AUTO_OPS").is_some_and(|x| x == "no") {
+            return Ok(());
+        }
+
         let miri_dir = miri_dir()?;
         let auto_everything = path!(miri_dir / ".auto-everything").exists();
         let auto_toolchain = auto_everything || path!(miri_dir / ".auto-toolchain").exists();
@@ -78,6 +82,7 @@ impl Command {
     }
 
     pub fn exec(self) -> Result<()> {
+        // First, and crucially only once, run the auto-actions -- but not for all commands.
         match &self {
             Command::Install { .. }
             | Command::Build { .. }
@@ -93,6 +98,7 @@ impl Command {
             | Command::Bench { .. }
             | Command::RustcPush { .. } => {}
         }
+        // Then run the actual command.
         match self {
             Command::Install { flags } => Self::install(flags),
             Command::Build { flags } => Self::build(flags),

src/tools/miri/rust-version

@@ -1 +1 @@
-656ee47db32e882fb02913f6204e09cc7a41a50e
+c40cfcf0494ff7506e753e750adb00eeea839f9c

src/tools/miri/src/borrow_tracker/tree_borrows/perms.rs

@@ -68,17 +68,31 @@ mod transition {
     fn foreign_read(state: PermissionPriv, protected: bool) -> Option<PermissionPriv> {
         use Option::*;
         Some(match state {
+            // Non-writeable states just ignore foreign reads.
+            non_writeable @ (Frozen | Disabled) => non_writeable,
+            // Writeable states are more tricky, and depend on whether things are protected.
             // The inner data `ty_is_freeze` of `Reserved` is always irrelevant for Read
             // accesses, since the data is not being mutated. Hence the `{ .. }`
-            res @ Reserved { .. } if !protected => res,
-            Reserved { .. } => Frozen, // protected reserved
+            res @ Reserved { .. } =>
+                if protected {
+                    // Someone else read, make sure we won't write.
+                    // We could make this `Disabled` but it doesn't look like we get anything out of that extra UB.
+                    Frozen
+                } else {
+                    // Before activation and without protectors, foreign reads are fine.
+                    // That's the entire point of 2-phase borrows.
+                    res
+                },
             Active =>
                 if protected {
+                    // We wrote, someone else reads -- that's bad.
+                    // (If this is initialized, this move-to-protected will mean insta-UB.)
                     Disabled
                 } else {
+                    // We don't want to disable here to allow read-read reordering: it is crucial
+                    // that the foreign read does not invalidate future reads through this tag.
                     Frozen
                 },
-            non_writeable @ (Frozen | Disabled) => non_writeable,
         })
     }
 

src/tools/miri/src/shims/intrinsics/mod.rs

@@ -44,7 +44,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                     "the program aborted execution".to_owned()
                 ))
             }
-            _ => {},
+            _ => {}
         }
 
         // All remaining supported intrinsics have a return place.