add option to track a particular AllocId (does nothing yet)

benches/helpers/miri_helper.rs

@@ -29,16 +29,7 @@ fn after_analysis<'tcx>(
                 tcx.entry_fn(LOCAL_CRATE).expect("no main or start function found");
 
             self.bencher.iter(|| {
-                let config = miri::MiriConfig {
-                    validate: true,
-                    stacked_borrows: true,
-                    communicate: false,
-                    ignore_leaks: false,
-                    excluded_env_vars: vec![],
-                    args: vec![],
-                    seed: None,
-                    tracked_pointer_tag: None,
-                };
+                let config = miri::MiriConfig::default();
                 eval_main(tcx, entry_def_id, config);
             });
         });

src/bin/miri-rustc-tests.rs

@@ -46,16 +46,7 @@ fn visit_item(&mut self, i: &'hir hir::Item) {
                                 .iter()
                                 .any(|attr| attr.check_name(rustc_span::symbol::sym::test))
                             {
-                                let config = MiriConfig {
-                                    validate: true,
-                                    stacked_borrows: true,
-                                    communicate: false,
-                                    ignore_leaks: false,
-                                    excluded_env_vars: vec![],
-                                    args: vec![],
-                                    seed: None,
-                                    tracked_pointer_tag: None,
-                                };
+                                let config = MiriConfig::default();
                                 let did = self.0.hir().body_owner_def_id(body_id);
                                 println!("running test: {}", self.0.def_path_debug_str(did));
                                 miri::eval_main(self.0, did, config);
@@ -68,16 +59,7 @@ fn visit_impl_item(&mut self, _impl_item: &'hir hir::ImplItem) {}
                 }
                 tcx.hir().krate().visit_all_item_likes(&mut Visitor(tcx));
             } else if let Some((entry_def_id, _)) = tcx.entry_fn(LOCAL_CRATE) {
-                let config = MiriConfig {
-                    validate: true,
-                    stacked_borrows: true,
-                    communicate: false,
-                    ignore_leaks: false,
-                    excluded_env_vars: vec![],
-                    args: vec![],
-                    seed: None,
-                    tracked_pointer_tag: None,
-                };
+                let config = MiriConfig::default();
                 miri::eval_main(tcx, entry_def_id, config);
 
                 compiler.session().abort_if_errors();

src/bin/miri.rs

@@ -135,6 +135,7 @@ fn main() {
     let mut ignore_leaks = false;
     let mut seed: Option<u64> = None;
     let mut tracked_pointer_tag: Option<miri::PtrId> = None;
+    let mut tracked_alloc_id: Option<miri::AllocId> = None;
     let mut rustc_args = vec![];
     let mut miri_args = vec![];
     let mut after_dashdash = false;
@@ -206,6 +207,17 @@ fn main() {
                         panic!("-Zmiri-track-pointer-tag must be a nonzero id");
                     }
                 }
+                arg if arg.starts_with("-Zmiri-track-alloc-id=") => {
+                    let id: u64 = match arg.trim_start_matches("-Zmiri-track-alloc-id=").parse()
+                    {
+                        Ok(id) => id,
+                        Err(err) => panic!(
+                            "-Zmiri-track-alloc-id requires a valid `u64` as the argument: {}",
+                            err
+                        ),
+                    };
+                    tracked_alloc_id = Some(miri::AllocId(id));
+                }
                 _ => {
                     rustc_args.push(arg);
                 }
@@ -240,6 +252,7 @@ fn main() {
         seed,
         args: miri_args,
         tracked_pointer_tag,
+        tracked_alloc_id,
     };
     rustc_driver::install_ice_hook();
     let result = rustc_driver::catch_fatal_errors(move || {

src/eval.rs

@@ -30,6 +30,24 @@ pub struct MiriConfig {
     pub seed: Option<u64>,
     /// The stacked borrow id to report about
     pub tracked_pointer_tag: Option<PtrId>,
+    /// The allocation id to report about.
+    pub tracked_alloc_id: Option<AllocId>,
+}
+
+impl Default for MiriConfig {
+    fn default() -> MiriConfig {
+        MiriConfig {
+            validate: true,
+            stacked_borrows: true,
+            communicate: false,
+            ignore_leaks: false,
+            excluded_env_vars: vec![],
+            args: vec![],
+            seed: None,
+            tracked_pointer_tag: None,
+            tracked_alloc_id: None,
+        }
+    }
 }
 
 /// Details of premature program termination.
@@ -55,6 +73,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
             StdRng::seed_from_u64(config.seed.unwrap_or(0)),
             config.stacked_borrows,
             config.tracked_pointer_tag,
+            config.tracked_alloc_id,
         ),
     );
     // Complete initialization.

src/machine.rs

@@ -75,15 +75,19 @@ pub struct MemoryExtra {
     pub intptrcast: intptrcast::MemoryExtra,
 
     /// Mapping extern static names to their canonical allocation.
-    pub(crate) extern_statics: FxHashMap<Symbol, AllocId>,
+    extern_statics: FxHashMap<Symbol, AllocId>,
 
     /// The random number generator used for resolving non-determinism.
     /// Needs to be queried by ptr_to_int, hence needs interior mutability.
     pub(crate) rng: RefCell<StdRng>,
+
+    /// An allocation ID to report when it is being allocated
+    /// (helps for debugging memory leaks).
+    tracked_alloc_id: Option<AllocId>,
 }
 
 impl MemoryExtra {
-    pub fn new(rng: StdRng, stacked_borrows: bool, tracked_pointer_tag: Option<PtrId>) -> Self {
+    pub fn new(rng: StdRng, stacked_borrows: bool, tracked_pointer_tag: Option<PtrId>, tracked_alloc_id: Option<AllocId>) -> Self {
         let stacked_borrows = if stacked_borrows {
             Some(Rc::new(RefCell::new(stacked_borrows::GlobalState::new(tracked_pointer_tag))))
         } else {
@@ -94,6 +98,7 @@ pub fn new(rng: StdRng, stacked_borrows: bool, tracked_pointer_tag: Option<PtrId
             intptrcast: Default::default(),
             extern_statics: FxHashMap::default(),
             rng: RefCell::new(rng),
+            tracked_alloc_id,
         }
     }