add separate allocator for MiriMachine

Author: nia-e

miri-script/src/commands.rs

@@ -1,4 +1,4 @@
-use std::collections::BTreeMap;
+use std::collections::HashMap;
 use std::ffi::{OsStr, OsString};
 use std::fmt::Write as _;
 use std::fs::{self, File};
@@ -489,9 +489,7 @@ impl Command {
             sh.read_dir(benches_dir)?
                 .into_iter()
                 .filter(|path| path.is_dir())
-                // Only keep the basename: that matches the usage with a manual bench list,
-                // and it ensure the path concatenations below work as intended.
-                .map(|path| path.file_name().unwrap().to_owned().into_string().unwrap())
+                .map(|path| path.into_os_string().into_string().unwrap())
                 .collect()
         } else {
             benches.into_iter().collect()
@@ -532,16 +530,14 @@ impl Command {
             stddev: f64,
         }
 
-        let gather_results = || -> Result<BTreeMap<&str, BenchResult>> {
+        let gather_results = || -> Result<HashMap<&str, BenchResult>> {
             let baseline_temp_dir = results_json_dir.unwrap();
-            let mut results = BTreeMap::new();
+            let mut results = HashMap::new();
             for bench in &benches {
-                let result = File::open(path!(baseline_temp_dir / format!("{bench}.bench.json")))
-                    .context("failed to read hyperfine JSON")?;
-                let mut result: serde_json::Value = serde_json::from_reader(BufReader::new(result))
-                    .context("failed to parse hyperfine JSON")?;
-                let result: BenchResult = serde_json::from_value(result["results"][0].take())
-                    .context("failed to interpret hyperfine JSON")?;
+                let result = File::open(path!(baseline_temp_dir / format!("{bench}.bench.json")))?;
+                let mut result: serde_json::Value =
+                    serde_json::from_reader(BufReader::new(result))?;
+                let result: BenchResult = serde_json::from_value(result["results"][0].take())?;
                 results.insert(bench as &str, result);
             }
             Ok(results)
@@ -553,15 +549,15 @@ impl Command {
             serde_json::to_writer_pretty(BufWriter::new(baseline), &results)?;
         } else if let Some(baseline_file) = load_baseline {
             let new_results = gather_results()?;
-            let baseline_results: BTreeMap<String, BenchResult> = {
+            let baseline_results: HashMap<String, BenchResult> = {
                 let f = File::open(baseline_file)?;
                 serde_json::from_reader(BufReader::new(f))?
             };
             println!(
                 "Comparison with baseline (relative speed, lower is better for the new results):"
             );
-            for (bench, new_result) in new_results {
-                let Some(baseline_result) = baseline_results.get(bench) else { continue };
+            for (bench, new_result) in new_results.iter() {
+                let Some(baseline_result) = baseline_results.get(*bench) else { continue };
 
                 // Compare results (inspired by hyperfine)
                 let ratio = new_result.mean / baseline_result.mean;

src/alloc_bytes.rs renamed to src/alloc/alloc_bytes.rs

@@ -5,8 +5,16 @@ use std::{alloc, slice};
 use rustc_abi::{Align, Size};
 use rustc_middle::mir::interpret::AllocBytes;
 
+#[cfg(target_os = "linux")]
+use crate::alloc::isolated_alloc::IsolatedAlloc;
 use crate::helpers::ToU64 as _;
 
+#[derive(Clone, Copy, Debug)]
+pub enum MiriAllocParams {
+    Global,
+    Isolated,
+}
+
 /// Allocation bytes that explicitly handle the layout of the data they're storing.
 /// This is necessary to interface with native code that accesses the program store in Miri.
 #[derive(Debug)]
@@ -18,13 +26,16 @@ pub struct MiriAllocBytes {
     /// * If `self.layout.size() == 0`, then `self.ptr` was allocated with the equivalent layout with size 1.
     /// * Otherwise, `self.ptr` points to memory allocated with `self.layout`.
     ptr: *mut u8,
+    /// Whether this instance of `MiriAllocBytes` had its allocation created by calling `alloc::alloc()`
+    /// (`Global`) or the discrete allocator (`Isolated`)
+    params: MiriAllocParams,
 }
 
 impl Clone for MiriAllocBytes {
     fn clone(&self) -> Self {
         let bytes: Cow<'_, [u8]> = Cow::Borrowed(self);
         let align = Align::from_bytes(self.layout.align().to_u64()).unwrap();
-        MiriAllocBytes::from_bytes(bytes, align)
+        MiriAllocBytes::from_bytes(bytes, align, self.params)
     }
 }
 
@@ -37,8 +48,23 @@ impl Drop for MiriAllocBytes {
         } else {
             self.layout
         };
+
         // SAFETY: Invariant, `self.ptr` points to memory allocated with `self.layout`.
-        unsafe { alloc::dealloc(self.ptr, alloc_layout) }
+        unsafe {
+            match self.params {
+                MiriAllocParams::Global => alloc::dealloc(self.ptr, alloc_layout),
+                MiriAllocParams::Isolated => {
+                    #[cfg(target_os = "linux")]
+                    {
+                        IsolatedAlloc::dealloc(self.ptr, alloc_layout)
+                    }
+                    #[cfg(not(target_os = "linux"))]
+                    {
+                        unreachable!()
+                    }
+                }
+            }
+        }
     }
 }
 
@@ -67,6 +93,7 @@ impl MiriAllocBytes {
     fn alloc_with(
         size: u64,
         align: u64,
+        params: MiriAllocParams,
         alloc_fn: impl FnOnce(Layout) -> *mut u8,
     ) -> Result<MiriAllocBytes, ()> {
         let size = usize::try_from(size).map_err(|_| ())?;
@@ -80,19 +107,35 @@ impl MiriAllocBytes {
             Err(())
         } else {
             // SAFETY: All `MiriAllocBytes` invariants are fulfilled.
-            Ok(Self { ptr, layout })
+            Ok(Self { ptr, layout, params })
         }
     }
 }
 
 impl AllocBytes for MiriAllocBytes {
-    fn from_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>, align: Align) -> Self {
+    type AllocParams = MiriAllocParams;
+
+    fn from_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>, align: Align, params: MiriAllocParams) -> Self {
         let slice = slice.into();
         let size = slice.len();
         let align = align.bytes();
         // SAFETY: `alloc_fn` will only be used with `size != 0`.
-        let alloc_fn = |layout| unsafe { alloc::alloc(layout) };
-        let alloc_bytes = MiriAllocBytes::alloc_with(size.to_u64(), align, alloc_fn)
+        let alloc_fn = |layout| unsafe {
+            match params {
+                MiriAllocParams::Global => alloc::alloc(layout),
+                MiriAllocParams::Isolated => {
+                    #[cfg(target_os = "linux")]
+                    {
+                        IsolatedAlloc::alloc(layout)
+                    }
+                    #[cfg(not(target_os = "linux"))]
+                    {
+                        unreachable!()
+                    }
+                }
+            }
+        };
+        let alloc_bytes = MiriAllocBytes::alloc_with(size.to_u64(), align, params, alloc_fn)
             .unwrap_or_else(|()| {
                 panic!("Miri ran out of memory: cannot create allocation of {size} bytes")
             });
@@ -102,12 +145,26 @@ impl AllocBytes for MiriAllocBytes {
         alloc_bytes
     }
 
-    fn zeroed(size: Size, align: Align) -> Option<Self> {
+    fn zeroed(size: Size, align: Align, params: MiriAllocParams) -> Option<Self> {
         let size = size.bytes();
         let align = align.bytes();
         // SAFETY: `alloc_fn` will only be used with `size != 0`.
-        let alloc_fn = |layout| unsafe { alloc::alloc_zeroed(layout) };
-        MiriAllocBytes::alloc_with(size, align, alloc_fn).ok()
+        let alloc_fn = |layout| unsafe {
+            match params {
+                MiriAllocParams::Global => alloc::alloc_zeroed(layout),
+                MiriAllocParams::Isolated => {
+                    #[cfg(target_os = "linux")]
+                    {
+                        IsolatedAlloc::alloc_zeroed(layout)
+                    }
+                    #[cfg(not(target_os = "linux"))]
+                    {
+                        unreachable!()
+                    }
+                }
+            }
+        };
+        MiriAllocBytes::alloc_with(size, align, params, alloc_fn).ok()
     }
 
     fn as_mut_ptr(&mut self) -> *mut u8 {