357 lines
12 KiB
Rust
357 lines
12 KiB
Rust
use rustc::middle::{const_eval, def_id, ty};
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use rustc_mir::mir_map::MirMap;
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use rustc_mir::repr::{self as mir, Mir};
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use syntax::ast::Attribute;
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use syntax::attr::AttrMetaMethods;
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use std::iter;
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const TRACE_EXECUTION: bool = false;
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#[derive(Clone, Debug, PartialEq)]
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enum Value {
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Uninit,
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Bool(bool),
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Int(i64), // FIXME: Should be bit-width aware.
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Func(def_id::DefId),
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}
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#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
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enum Pointer {
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Stack(usize),
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// TODO(tsion): Heap
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}
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/// A stack frame:
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///
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/// ```text
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/// +-----------------------+
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/// | ReturnPointer | return value
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/// + - - - - - - - - - - - +
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/// | Arg(0) |
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/// | Arg(1) | arguments
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/// | ... |
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/// | Arg(num_args - 1) |
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/// + - - - - - - - - - - - +
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/// | Var(0) |
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/// | Var(1) | variables
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/// | ... |
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/// | Var(num_vars - 1) |
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/// + - - - - - - - - - - - +
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/// | Temp(0) |
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/// | Temp(1) | temporaries
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/// | ... |
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/// | Temp(num_temps - 1) |
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/// + - - - - - - - - - - - +
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/// | Aggregates | aggregates
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/// +-----------------------+
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/// ```
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#[derive(Debug)]
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struct Frame {
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offset: usize,
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num_args: usize,
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num_vars: usize,
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num_temps: usize,
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// aggregates
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}
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impl Frame {
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fn size(&self) -> usize {
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1 + self.num_args + self.num_vars + self.num_temps
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}
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fn return_val_offset(&self) -> usize {
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self.offset
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}
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fn arg_offset(&self, i: u32) -> usize {
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self.offset + 1 + i as usize
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}
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fn var_offset(&self, i: u32) -> usize {
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self.offset + 1 + self.num_args + i as usize
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}
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fn temp_offset(&self, i: u32) -> usize {
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self.offset + 1 + self.num_args + self.num_vars + i as usize
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}
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}
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struct Interpreter<'a, 'tcx: 'a> {
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tcx: &'a ty::ctxt<'tcx>,
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mir_map: &'a MirMap<'tcx>,
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value_stack: Vec<Value>,
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call_stack: Vec<Frame>,
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}
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impl<'a, 'tcx> Interpreter<'a, 'tcx> {
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fn new(tcx: &'a ty::ctxt<'tcx>, mir_map: &'a MirMap<'tcx>) -> Self {
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Interpreter {
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tcx: tcx,
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mir_map: mir_map,
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value_stack: Vec::new(),
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call_stack: Vec::new(),
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}
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}
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fn push_stack_frame(&mut self, mir: &Mir, args: &[Value]) {
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self.call_stack.push(Frame {
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offset: self.value_stack.len(),
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num_args: mir.arg_decls.len(),
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num_vars: mir.var_decls.len(),
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num_temps: mir.temp_decls.len(),
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});
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let frame = self.call_stack.last().unwrap();
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self.value_stack.extend(iter::repeat(Value::Uninit).take(frame.size()));
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for (i, arg) in args.iter().enumerate() {
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self.value_stack[frame.offset + 1 + i] = arg.clone();
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}
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}
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fn pop_stack_frame(&mut self) {
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let frame = self.call_stack.pop().expect("tried to pop stack frame, but there were none");
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self.value_stack.truncate(frame.offset);
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}
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fn call(&mut self, mir: &Mir, args: &[Value]) -> Value {
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self.push_stack_frame(mir, args);
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let mut block = mir::START_BLOCK;
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loop {
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use rustc_mir::repr::Terminator::*;
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let block_data = mir.basic_block_data(block);
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for stmt in &block_data.statements {
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use rustc_mir::repr::StatementKind::*;
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if TRACE_EXECUTION { println!("{:?}", stmt); }
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match stmt.kind {
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Assign(ref lvalue, ref rvalue) => {
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let ptr = self.eval_lvalue(lvalue);
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let value = self.eval_rvalue(rvalue);
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self.write_pointer(ptr, value);
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}
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Drop(_kind, ref _lv) => {
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// TODO
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},
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}
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}
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if TRACE_EXECUTION { println!("{:?}", block_data.terminator); }
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match block_data.terminator {
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Return => break,
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Goto { target } => block = target,
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Call { data: mir::CallData { ref destination, ref func, ref args }, targets } => {
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let ptr = self.eval_lvalue(destination);
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let func_val = self.eval_operand(func);
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if let Value::Func(def_id) = func_val {
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let node_id = self.tcx.map.as_local_node_id(def_id).unwrap();
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let mir = &self.mir_map[&node_id];
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let arg_vals: Vec<Value> =
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args.iter().map(|arg| self.eval_operand(arg)).collect();
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// FIXME: Pass the destination lvalue such that the ReturnPointer inside
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// the function call will point to the destination.
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let return_val = self.call(mir, &arg_vals);
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self.write_pointer(ptr, return_val);
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block = targets[0];
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} else {
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panic!("tried to call a non-function value: {:?}", func_val);
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}
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}
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If { ref cond, targets } => {
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match self.eval_operand(cond) {
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Value::Bool(true) => block = targets[0],
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Value::Bool(false) => block = targets[1],
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cond_val => panic!("Non-boolean `if` condition value: {:?}", cond_val),
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}
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}
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SwitchInt { ref discr, switch_ty: _, ref values, ref targets } => {
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let discr_val = self.read_lvalue(discr);
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let index = values.iter().position(|v| discr_val == self.eval_constant(v))
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.expect("discriminant matched no values");
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block = targets[index];
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}
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// Diverge => unimplemented!(),
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// Panic { target } => unimplemented!(),
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// Switch { ref discr, adt_def, ref targets } => unimplemented!(),
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_ => unimplemented!(),
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}
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}
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let ret_val = self.read_lvalue(&mir::Lvalue::ReturnPointer);
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self.pop_stack_frame();
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ret_val
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}
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fn eval_lvalue(&self, lvalue: &mir::Lvalue) -> Pointer {
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use rustc_mir::repr::Lvalue::*;
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let frame = self.call_stack.last().expect("missing call frame");
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match *lvalue {
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ReturnPointer => Pointer::Stack(frame.return_val_offset()),
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Arg(i) => Pointer::Stack(frame.arg_offset(i)),
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Var(i) => Pointer::Stack(frame.var_offset(i)),
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Temp(i) => Pointer::Stack(frame.temp_offset(i)),
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_ => unimplemented!(),
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}
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}
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fn eval_rvalue(&mut self, rvalue: &mir::Rvalue) -> Value {
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use rustc_mir::repr::Rvalue::*;
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use rustc_mir::repr::BinOp::*;
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use rustc_mir::repr::UnOp::*;
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match *rvalue {
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Use(ref operand) => self.eval_operand(operand),
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BinaryOp(bin_op, ref left, ref right) => {
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match (self.eval_operand(left), self.eval_operand(right)) {
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(Value::Int(l), Value::Int(r)) => {
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match bin_op {
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Add => Value::Int(l + r),
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Sub => Value::Int(l - r),
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Mul => Value::Int(l * r),
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Div => Value::Int(l / r),
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Rem => Value::Int(l % r),
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BitXor => Value::Int(l ^ r),
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BitAnd => Value::Int(l & r),
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BitOr => Value::Int(l | r),
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Shl => Value::Int(l << r),
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Shr => Value::Int(l >> r),
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Eq => Value::Bool(l == r),
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Lt => Value::Bool(l < r),
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Le => Value::Bool(l <= r),
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Ne => Value::Bool(l != r),
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Ge => Value::Bool(l >= r),
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Gt => Value::Bool(l > r),
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}
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}
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_ => unimplemented!(),
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}
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}
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UnaryOp(un_op, ref operand) => {
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match (un_op, self.eval_operand(operand)) {
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(Not, Value::Int(n)) => Value::Int(!n),
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(Neg, Value::Int(n)) => Value::Int(-n),
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_ => unimplemented!(),
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}
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}
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// Aggregate(mir::AggregateKind::Adt(ref adt_def, variant, substs), ref operands) => {
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// let num_fields = adt_def.variants[variant].fields.len();
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// debug_assert_eq!(num_fields, operands.len());
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// let data = operands.iter().map(|op| self.eval_operand(op)).collect();
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// Value::Adt(variant, data)
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// }
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_ => unimplemented!(),
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}
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}
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fn eval_operand(&mut self, op: &mir::Operand) -> Value {
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use rustc_mir::repr::Operand::*;
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match *op {
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Consume(ref lvalue) => self.read_lvalue(lvalue),
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Constant(ref constant) => {
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match constant.literal {
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mir::Literal::Value { ref value } => self.eval_constant(value),
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mir::Literal::Item { def_id, substs: _ } => {
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Value::Func(def_id)
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}
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}
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}
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}
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}
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fn eval_constant(&self, const_val: &const_eval::ConstVal) -> Value {
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use rustc::middle::const_eval::ConstVal::*;
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match *const_val {
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Float(_f) => unimplemented!(),
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Int(i) => Value::Int(i),
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Uint(_u) => unimplemented!(),
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Str(ref _s) => unimplemented!(),
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ByteStr(ref _bs) => unimplemented!(),
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Bool(b) => Value::Bool(b),
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Struct(_node_id) => unimplemented!(),
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Tuple(_node_id) => unimplemented!(),
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Function(_def_id) => unimplemented!(),
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}
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}
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fn read_lvalue(&self, lvalue: &mir::Lvalue) -> Value {
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self.read_pointer(self.eval_lvalue(lvalue))
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}
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fn read_pointer(&self, p: Pointer) -> Value {
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match p {
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Pointer::Stack(offset) => self.value_stack[offset].clone(),
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}
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}
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fn write_pointer(&mut self, p: Pointer, val: Value) {
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match p {
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Pointer::Stack(offset) => self.value_stack[offset] = val,
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}
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}
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}
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pub fn interpret_start_points<'tcx>(tcx: &ty::ctxt<'tcx>, mir_map: &MirMap<'tcx>) {
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for (&id, mir) in mir_map {
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for attr in tcx.map.attrs(id) {
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if attr.check_name("miri_run") {
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let item = tcx.map.expect_item(id);
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println!("Interpreting: {}", item.name);
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let mut interpreter = Interpreter::new(tcx, mir_map);
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let val = interpreter.call(mir, &[]);
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let val_str = format!("{:?}", val);
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if !check_expected(&val_str, attr) {
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println!("=> {}\n", val_str);
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}
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}
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}
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}
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}
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fn check_expected(actual: &str, attr: &Attribute) -> bool {
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if let Some(meta_items) = attr.meta_item_list() {
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for meta_item in meta_items {
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if meta_item.check_name("expected") {
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let expected = meta_item.value_str().unwrap();
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if actual == &expected[..] {
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println!("Test passed!\n");
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} else {
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println!("Actual value:\t{}\nExpected value:\t{}\n", actual, expected);
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}
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return true;
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}
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}
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}
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false
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}
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