rustup for Retagging

appveyor.yml

@@ -14,19 +14,20 @@ branches:
     - master
 
 install:
-    # install Rust
+    # Install Rust.
     - set PATH=C:\Program Files\Git\mingw64\bin;C:\msys64\mingw%MSYS2_BITS%\bin;%PATH%
     - set /p RUST_TOOLCHAIN=<rust-version
     - curl -sSf -o rustup-init.exe https://win.rustup.rs/
     - rustup-init.exe -y --default-host %TARGET% --default-toolchain %RUST_TOOLCHAIN%
     - set PATH=%USERPROFILE%\.cargo\bin;%PATH%
     - rustc --version
-    # customize installation
+    # Customize installation.
     - rustup component add rust-src
     - cargo install xargo
-    # prepare a libstd with MIR (cannot use bash script, obviously)
+    # Prepare a libstd with MIR (cannot use bash script, obviously).
+    # The flags here should be kept in sync with `add_miri_default_args` in `src/lib.rs`.
     - cd xargo
-    - set RUSTFLAGS=-Zalways-encode-mir -Zmir-emit-validate=1
+    - set RUSTFLAGS=-Zalways-encode-mir -Zmir-emit-retag -Zmir-opt-level=0
     - xargo build
     - set RUSTFLAGS=
     - cd ..

src/bin/cargo-miri.rs

@@ -186,7 +186,7 @@ fn main() {
             Command::new("rustc")
         };
 
-        args.extend_from_slice(&["-Z".to_owned(), "always-encode-mir".to_owned()]);
+        miri::add_miri_default_args(&mut args);
         args.extend_from_slice(&["--cfg".to_owned(), r#"feature="cargo-miri""#.to_owned()]);
 
         match command.args(&args).status() {

src/bin/miri-rustc-tests.rs

@@ -165,9 +165,7 @@ fn main() {
             args.push(Path::new(&std::env::var("HOME").unwrap()).join(".xargo").join("HOST").display().to_string());
         }
 
-        args.push("-Zmir-opt-level=3".to_owned());
-        // for auxilary builds in unit tests
-        args.push("-Zalways-encode-mir".to_owned());
+        miri::add_miri_default_args(&mut args);
 
         // A threadsafe buffer for writing.
         #[derive(Default, Clone)]

src/bin/miri.rs

@@ -10,6 +10,8 @@ extern crate rustc_codegen_utils;
 extern crate env_logger;
 extern crate log_settings;
 extern crate syntax;
+
+#[macro_use]
 extern crate log;
 
 use std::path::PathBuf;
@@ -212,12 +214,7 @@ fn main() {
     init_early_loggers();
     let mut args: Vec<String> = std::env::args().collect();
 
-    let sysroot_flag = String::from("--sysroot");
-    if !args.contains(&sysroot_flag) {
-        args.push(sysroot_flag);
-        args.push(find_sysroot());
-    }
-
+    // Parse our own -Z flags and remove them before rustc gets their hand on them.
     let mut validate = true;
     args.retain(|arg| {
         match arg.as_str() {
@@ -229,7 +226,16 @@ fn main() {
         }
     });
 
+    // Determine sysroot and let rustc know about it
+    let sysroot_flag = String::from("--sysroot");
+    if !args.contains(&sysroot_flag) {
+        args.push(sysroot_flag);
+        args.push(find_sysroot());
+    }
+    // Finally, add the default flags all the way in the beginning.
+    miri::add_miri_default_args(&mut args);
 
+    trace!("rustc arguments: {:?}", args);
     let result = rustc_driver::run(move || {
         rustc_driver::run_compiler(&args, Box::new(MiriCompilerCalls {
             default: Box::new(RustcDefaultCalls),

src/lib.rs

@@ -26,7 +26,7 @@ use syntax::attr;
 
 
 pub use rustc_mir::interpret::*;
-pub use rustc_mir::interpret::{self, AllocMap}; // resolve ambiguity
+pub use rustc_mir::interpret::{self, AllocMap, PlaceTy}; // resolve ambiguity
 
 mod fn_call;
 mod operator;
@@ -48,7 +48,21 @@ use mono_hash_map::MonoHashMap;
 use stacked_borrows::{EvalContextExt as StackedBorEvalContextExt};
 
 // Used by priroda
-pub use stacked_borrows::{Borrow, Stacks, Mut as MutBorrow};
+pub use crate::stacked_borrows::{Borrow, Stack, Stacks, Mut as MutBorrow, BorStackItem};
+
+/// Insert rustc arguments at the beginning of the argument listthat miri wants to be
+/// set per default, for maximal validation power.
+pub fn add_miri_default_args(args: &mut Vec<String>) {
+    // The flags here should be kept in sync with what bootstrap adds when `test-miri` is
+    // set, which happens in `bootstrap/bin/rustc.rs` in the rustc sources; and also
+    // kept in sync with `xargo/build.sh` in this repo and `appveyor.yml`.
+
+    // Inserting at index 1, after the binary name
+    args.splice(1..1,
+        ["-Zalways-encode-mir", "-Zmir-emit-retag", "-Zmir-opt-level=0"]
+        .iter().map(|s| s.to_string())
+    );
+}
 
 // Used by priroda
 pub fn create_ecx<'a, 'mir: 'a, 'tcx: 'mir>(
@@ -438,21 +452,30 @@ impl<'a, 'mir, 'tcx> Machine<'a, 'mir, 'tcx> for Evaluator<'tcx> {
     }
 
     #[inline(always)]
-    fn memory_accessed(
+    fn memory_read(
         alloc: &Allocation<Borrow, Self::AllocExtra>,
         ptr: Pointer<Borrow>,
         size: Size,
-        access: MemoryAccess,
     ) -> EvalResult<'tcx> {
-        alloc.extra.memory_accessed(ptr, size, access)
+        alloc.extra.memory_read(ptr, size)
+    }
+
+    #[inline(always)]
+    fn memory_written(
+        alloc: &mut Allocation<Borrow, Self::AllocExtra>,
+        ptr: Pointer<Borrow>,
+        size: Size,
+    ) -> EvalResult<'tcx> {
+        alloc.extra.memory_written(ptr, size)
     }
 
     #[inline(always)]
     fn memory_deallocated(
         alloc: &mut Allocation<Borrow, Self::AllocExtra>,
         ptr: Pointer<Borrow>,
+        size: Size,
     ) -> EvalResult<'tcx> {
-        alloc.extra.memory_deallocated(ptr)
+        alloc.extra.memory_deallocated(ptr, size)
     }
 
     #[inline(always)]
@@ -507,4 +530,20 @@ impl<'a, 'mir, 'tcx> Machine<'a, 'mir, 'tcx> for Evaluator<'tcx> {
             Ok(Pointer::new_with_tag(ptr.alloc_id, ptr.offset, tag))
         }
     }
+
+    #[inline(always)]
+    fn retag(
+        ecx: &mut EvalContext<'a, 'mir, 'tcx, Self>,
+        fn_entry: bool,
+        place: PlaceTy<'tcx, Borrow>,
+    ) -> EvalResult<'tcx> {
+        if !ecx.tcx.sess.opts.debugging_opts.mir_emit_retag || !Self::enforce_validity(ecx) {
+            // No tracking, or no retagging. This is possible because a dependency of ours might be
+            // called with different flags than we are,
+            // Also, honor the whitelist in `enforce_validity` because otherwise we might retag
+            // uninitialized data.
+            return Ok(())
+        }
+        ecx.retag(fn_entry, place)
+    }
 }