move most of the stuff from lib.rs into machine.rs, and initialization + main loop into eval.rs

Author: RalfJung

src/eval.rs

@@ -0,0 +1,248 @@
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+
+use syntax::source_map::DUMMY_SP;
+use rustc::ty::{self, TyCtxt};
+use rustc::ty::layout::{LayoutOf, Size, Align};
+use rustc::hir::def_id::DefId;
+use rustc::mir;
+
+use crate::{
+    InterpResult, InterpError, InterpretCx, StackPopCleanup, struct_error,
+    Scalar, Tag, Pointer,
+    MiriMemoryKind, Evaluator, TlsEvalContextExt,
+};
+
+/// Configuration needed to spawn a Miri instance.
+#[derive(Clone)]
+pub struct MiriConfig {
+    pub validate: bool,
+    pub args: Vec<String>,
+
+    // The seed to use when non-determinism is required (e.g. getrandom())
+    pub seed: Option<u64>
+}
+
+// Used by priroda.
+pub fn create_ecx<'mir, 'tcx: 'mir>(
+    tcx: TyCtxt<'tcx>,
+    main_id: DefId,
+    config: MiriConfig,
+) -> InterpResult<'tcx, InterpretCx<'mir, 'tcx, Evaluator<'tcx>>> {
+    let mut ecx = InterpretCx::new(
+        tcx.at(syntax::source_map::DUMMY_SP),
+        ty::ParamEnv::reveal_all(),
+        Evaluator::new(config.validate),
+    );
+
+    // FIXME: InterpretCx::new should take an initial MemoryExtra
+    ecx.memory_mut().extra.rng = config.seed.map(StdRng::seed_from_u64);
+    
+    let main_instance = ty::Instance::mono(ecx.tcx.tcx, main_id);
+    let main_mir = ecx.load_mir(main_instance.def)?;
+
+    if !main_mir.return_ty().is_unit() || main_mir.arg_count != 0 {
+        return err!(Unimplemented(
+            "miri does not support main functions without `fn()` type signatures"
+                .to_owned(),
+        ));
+    }
+
+    let start_id = tcx.lang_items().start_fn().unwrap();
+    let main_ret_ty = tcx.fn_sig(main_id).output();
+    let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
+    let start_instance = ty::Instance::resolve(
+        ecx.tcx.tcx,
+        ty::ParamEnv::reveal_all(),
+        start_id,
+        ecx.tcx.mk_substs(
+            ::std::iter::once(ty::subst::Kind::from(main_ret_ty)))
+        ).unwrap();
+    let start_mir = ecx.load_mir(start_instance.def)?;
+
+    if start_mir.arg_count != 3 {
+        return err!(AbiViolation(format!(
+            "'start' lang item should have three arguments, but has {}",
+            start_mir.arg_count
+        )));
+    }
+
+    // Return value (in static memory so that it does not count as leak).
+    let ret = ecx.layout_of(start_mir.return_ty())?;
+    let ret_ptr = ecx.allocate(ret, MiriMemoryKind::Static.into());
+
+    // Push our stack frame.
+    ecx.push_stack_frame(
+        start_instance,
+        // There is no call site.
+        DUMMY_SP,
+        start_mir,
+        Some(ret_ptr.into()),
+        StackPopCleanup::None { cleanup: true },
+    )?;
+
+    let mut args = ecx.frame().body.args_iter();
+
+    // First argument: pointer to `main()`.
+    let main_ptr = ecx.memory_mut().create_fn_alloc(main_instance);
+    let dest = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
+    ecx.write_scalar(Scalar::Ptr(main_ptr), dest)?;
+
+    // Second argument (argc): `1`.
+    let dest = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
+    let argc = Scalar::from_uint(config.args.len() as u128, dest.layout.size);
+    ecx.write_scalar(argc, dest)?;
+    // Store argc for macOS's `_NSGetArgc`.
+    {
+        let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
+        ecx.write_scalar(argc, argc_place.into())?;
+        ecx.machine.argc = Some(argc_place.ptr.to_ptr()?);
+    }
+
+    // FIXME: extract main source file path.
+    // Third argument (`argv`): created from `config.args`.
+    let dest = ecx.eval_place(&mir::Place::Base(mir::PlaceBase::Local(args.next().unwrap())))?;
+    // For Windows, construct a command string with all the aguments.
+    let mut cmd = String::new();
+    for arg in config.args.iter() {
+        if !cmd.is_empty() {
+            cmd.push(' ');
+        }
+        cmd.push_str(&*shell_escape::windows::escape(arg.as_str().into()));
+    }
+    // Don't forget `0` terminator.
+    cmd.push(std::char::from_u32(0).unwrap());
+    // Collect the pointers to the individual strings.
+    let mut argvs = Vec::<Pointer<Tag>>::new();
+    for arg in config.args {
+        // Add `0` terminator.
+        let mut arg = arg.into_bytes();
+        arg.push(0);
+        argvs.push(ecx.memory_mut().allocate_static_bytes(arg.as_slice(), MiriMemoryKind::Static.into()));
+    }
+    // Make an array with all these pointers, in the Miri memory.
+    let argvs_layout = ecx.layout_of(ecx.tcx.mk_array(ecx.tcx.mk_imm_ptr(ecx.tcx.types.u8), argvs.len() as u64))?;
+    let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Env.into());
+    for (idx, arg) in argvs.into_iter().enumerate() {
+        let place = ecx.mplace_field(argvs_place, idx as u64)?;
+        ecx.write_scalar(Scalar::Ptr(arg), place.into())?;
+    }
+    ecx.memory_mut().mark_immutable(argvs_place.to_ptr()?.alloc_id)?;
+    // Write a pointer to that place as the argument.
+    let argv = argvs_place.ptr;
+    ecx.write_scalar(argv, dest)?;
+    // Store `argv` for macOS `_NSGetArgv`.
+    {
+        let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into());
+        ecx.write_scalar(argv, argv_place.into())?;
+        ecx.machine.argv = Some(argv_place.ptr.to_ptr()?);
+    }
+    // Store command line as UTF-16 for Windows `GetCommandLineW`.
+    {
+        let tcx = &{ecx.tcx.tcx};
+        let cmd_utf16: Vec<u16> = cmd.encode_utf16().collect();
+        let cmd_ptr = ecx.memory_mut().allocate(
+            Size::from_bytes(cmd_utf16.len() as u64 * 2),
+            Align::from_bytes(2).unwrap(),
+            MiriMemoryKind::Env.into(),
+        );
+        ecx.machine.cmd_line = Some(cmd_ptr);
+        // Store the UTF-16 string.
+        let char_size = Size::from_bytes(2);
+        let cmd_alloc = ecx.memory_mut().get_mut(cmd_ptr.alloc_id)?;
+        let mut cur_ptr = cmd_ptr;
+        for &c in cmd_utf16.iter() {
+            cmd_alloc.write_scalar(
+                tcx,
+                cur_ptr,
+                Scalar::from_uint(c, char_size).into(),
+                char_size,
+            )?;
+            cur_ptr = cur_ptr.offset(char_size, tcx)?;
+        }
+    }
+ 
+    assert!(args.next().is_none(), "start lang item has more arguments than expected");
+
+    Ok(ecx)
+}
+
+pub fn eval_main<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    main_id: DefId,
+    config: MiriConfig,
+) {
+    let mut ecx = match create_ecx(tcx, main_id, config) {
+        Ok(ecx) => ecx,
+        Err(mut err) => {
+            err.print_backtrace();
+            panic!("Miri initialziation error: {}", err.kind)
+        }
+    };
+
+    // Perform the main execution.
+    let res: InterpResult = (|| {
+        ecx.run()?;
+        ecx.run_tls_dtors()
+    })();
+
+    // Process the result.
+    match res {
+        Ok(()) => {
+            let leaks = ecx.memory().leak_report();
+            // Disable the leak test on some platforms where we do not
+            // correctly implement TLS destructors.
+            let target_os = ecx.tcx.tcx.sess.target.target.target_os.to_lowercase();
+            let ignore_leaks = target_os == "windows" || target_os == "macos";
+            if !ignore_leaks && leaks != 0 {
+                tcx.sess.err("the evaluated program leaked memory");
+            }
+        }
+        Err(mut e) => {
+            // Special treatment for some error kinds
+            let msg = match e.kind {
+                InterpError::Exit(code) => std::process::exit(code),
+                InterpError::NoMirFor(..) =>
+                    format!("{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.", e),
+                _ => e.to_string()
+            };
+            e.print_backtrace();
+            if let Some(frame) = ecx.stack().last() {
+                let block = &frame.body.basic_blocks()[frame.block];
+                let span = if frame.stmt < block.statements.len() {
+                    block.statements[frame.stmt].source_info.span
+                } else {
+                    block.terminator().source_info.span
+                };
+
+                let msg = format!("Miri evaluation error: {}", msg);
+                let mut err = struct_error(ecx.tcx.tcx.at(span), msg.as_str());
+                let frames = ecx.generate_stacktrace(None);
+                err.span_label(span, msg);
+                // We iterate with indices because we need to look at the next frame (the caller).
+                for idx in 0..frames.len() {
+                    let frame_info = &frames[idx];
+                    let call_site_is_local = frames.get(idx+1).map_or(false,
+                        |caller_info| caller_info.instance.def_id().is_local());
+                    if call_site_is_local {
+                        err.span_note(frame_info.call_site, &frame_info.to_string());
+                    } else {
+                        err.note(&frame_info.to_string());
+                    }
+                }
+                err.emit();
+            } else {
+                ecx.tcx.sess.err(&msg);
+            }
+
+            for (i, frame) in ecx.stack().iter().enumerate() {
+                trace!("-------------------");
+                trace!("Frame {}", i);
+                trace!("    return: {:?}", frame.return_place.map(|p| *p));
+                for (i, local) in frame.locals.iter().enumerate() {
+                    trace!("    local {}: {:?}", i, local.value);
+                }
+            }
+        }
+    }
+}

src/helpers.rs

@@ -1,6 +1,6 @@
 use std::mem;
 
-use rustc::ty::{self, layout};
+use rustc::ty::{self, layout::{self, Size}};
 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX};
 
 use crate::*;