rust/src/interpreter.rs

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Rust
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use arena::TypedArena;
use rustc::middle::const_eval;
use rustc::middle::def_id::DefId;
use rustc::middle::infer;
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use rustc::middle::subst::{self, Subst, Substs};
use rustc::middle::traits;
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use rustc::middle::ty::{self, TyCtxt};
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use rustc::mir::mir_map::MirMap;
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use rustc::mir::repr as mir;
use rustc::util::nodemap::DefIdMap;
use rustc_data_structures::fnv::FnvHashMap;
use std::cell::RefCell;
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use std::iter;
use std::ops::Deref;
use std::rc::Rc;
use syntax::ast;
use syntax::attr;
use syntax::codemap::DUMMY_SP;
use error::{EvalError, EvalResult};
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use memory::{self, FieldRepr, Memory, Pointer, Repr};
use primval::{self, PrimVal};
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const TRACE_EXECUTION: bool = true;
struct Interpreter<'a, 'tcx: 'a, 'arena> {
/// The results of the type checker, from rustc.
tcx: &'a TyCtxt<'tcx>,
/// A mapping from NodeIds to Mir, from rustc. Only contains MIR for crate-local items.
mir_map: &'a MirMap<'tcx>,
/// A local cache from DefIds to Mir for non-crate-local items.
mir_cache: RefCell<DefIdMap<Rc<mir::Mir<'tcx>>>>,
/// An arena allocator for type representations.
repr_arena: &'arena TypedArena<Repr>,
/// A cache for in-memory representations of types.
repr_cache: RefCell<FnvHashMap<ty::Ty<'tcx>, &'arena Repr>>,
/// The virtual memory system.
memory: Memory,
/// The virtual call stack.
stack: Vec<Frame<'a, 'tcx>>,
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/// Another stack containing the type substitutions for the current function invocation. It
/// exists separately from `stack` because it must contain the `Substs` for a function while
/// *creating* the `Frame` for that same function.
substs_stack: Vec<&'tcx Substs<'tcx>>,
}
/// A stack frame.
struct Frame<'a, 'tcx: 'a> {
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/// The MIR for the function called on this frame.
mir: CachedMir<'a, 'tcx>,
/// The block this frame will execute when a function call returns back to this frame.
next_block: mir::BasicBlock,
/// A pointer for writing the return value of the current call if it's not a diverging call.
return_ptr: Option<Pointer>,
/// The list of locals for the current function, stored in order as
/// `[arguments..., variables..., temporaries...]`. The variables begin at `self.var_offset`
/// and the temporaries at `self.temp_offset`.
locals: Vec<Pointer>,
/// The offset of the first variable in `self.locals`.
var_offset: usize,
/// The offset of the first temporary in `self.locals`.
temp_offset: usize,
}
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#[derive(Clone)]
enum CachedMir<'mir, 'tcx: 'mir> {
Ref(&'mir mir::Mir<'tcx>),
Owned(Rc<mir::Mir<'tcx>>)
}
/// Represents the action to be taken in the main loop as a result of executing a terminator.
enum TerminatorTarget {
/// Make a local jump to the given block.
Block(mir::BasicBlock),
/// Start executing from the new current frame. (For function calls.)
Call,
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/// Stop executing the current frame and resume the previous frame.
Return,
}
impl<'a, 'tcx: 'a, 'arena> Interpreter<'a, 'tcx, 'arena> {
fn new(tcx: &'a TyCtxt<'tcx>, mir_map: &'a MirMap<'tcx>, repr_arena: &'arena TypedArena<Repr>)
-> Self
{
Interpreter {
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tcx: tcx,
mir_map: mir_map,
mir_cache: RefCell::new(DefIdMap()),
repr_arena: repr_arena,
repr_cache: RefCell::new(FnvHashMap()),
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memory: Memory::new(),
stack: Vec::new(),
substs_stack: Vec::new(),
}
}
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fn run(&mut self) -> EvalResult<()> {
use std::fmt::Debug;
fn print_trace<T: Debug>(t: &T, suffix: &'static str, indent: usize) {
if !TRACE_EXECUTION { return; }
for _ in 0..indent { print!(" "); }
println!("{:?}{}", t, suffix);
}
'outer: while !self.stack.is_empty() {
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let mut current_block = self.frame().next_block;
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loop {
print_trace(&current_block, ":", self.stack.len());
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let current_mir = self.mir().clone(); // Cloning a reference.
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let block_data = current_mir.basic_block_data(current_block);
for stmt in &block_data.statements {
print_trace(stmt, "", self.stack.len() + 1);
let mir::StatementKind::Assign(ref lvalue, ref rvalue) = stmt.kind;
try!(self.eval_assignment(lvalue, rvalue));
}
let terminator = block_data.terminator();
print_trace(terminator, "", self.stack.len() + 1);
match try!(self.eval_terminator(terminator)) {
TerminatorTarget::Block(block) => current_block = block,
TerminatorTarget::Return => {
self.pop_stack_frame();
self.substs_stack.pop();
continue 'outer;
}
TerminatorTarget::Call => continue 'outer,
}
}
}
Ok(())
}
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fn push_stack_frame(&mut self, mir: CachedMir<'a, 'tcx>, return_ptr: Option<Pointer>)
-> EvalResult<()>
{
let arg_tys = mir.arg_decls.iter().map(|a| a.ty);
let var_tys = mir.var_decls.iter().map(|v| v.ty);
let temp_tys = mir.temp_decls.iter().map(|t| t.ty);
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let locals: Vec<Pointer> = arg_tys.chain(var_tys).chain(temp_tys).map(|ty| {
let size = self.ty_size(ty);
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self.memory.allocate(size)
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}).collect();
let num_args = mir.arg_decls.len();
let num_vars = mir.var_decls.len();
self.stack.push(Frame {
mir: mir.clone(),
next_block: mir::START_BLOCK,
return_ptr: return_ptr,
locals: locals,
var_offset: num_args,
temp_offset: num_args + num_vars,
});
Ok(())
}
fn pop_stack_frame(&mut self) {
let _frame = self.stack.pop().expect("tried to pop a stack frame, but there were none");
// TODO(tsion): Deallocate local variables.
}
fn eval_terminator(&mut self, terminator: &mir::Terminator<'tcx>)
-> EvalResult<TerminatorTarget> {
use rustc::mir::repr::Terminator::*;
let target = match *terminator {
Return => TerminatorTarget::Return,
Goto { target } => TerminatorTarget::Block(target),
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If { ref cond, targets: (then_target, else_target) } => {
let cond_ptr = try!(self.eval_operand(cond));
let cond_val = try!(self.memory.read_bool(cond_ptr));
TerminatorTarget::Block(if cond_val { then_target } else { else_target })
}
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SwitchInt { ref discr, ref values, ref targets, .. } => {
let discr_ptr = try!(self.eval_lvalue(discr));
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let discr_size = self.lvalue_repr(discr).size();
let discr_val = try!(self.memory.read_uint(discr_ptr, discr_size));
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// Branch to the `otherwise` case by default, if no match is found.
let mut target_block = targets[targets.len() - 1];
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for (index, val_const) in values.iter().enumerate() {
let ptr = try!(self.const_to_ptr(val_const));
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let val = try!(self.memory.read_uint(ptr, discr_size));
if discr_val == val {
target_block = targets[index];
break;
}
}
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TerminatorTarget::Block(target_block)
}
Switch { ref discr, ref targets, .. } => {
let adt_ptr = try!(self.eval_lvalue(discr));
let adt_repr = self.lvalue_repr(discr);
let discr_size = match *adt_repr {
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Repr::Aggregate { discr_size, .. } => discr_size,
_ => panic!("attmpted to switch on non-aggregate type"),
};
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let discr_val = try!(self.memory.read_uint(adt_ptr, discr_size));
TerminatorTarget::Block(targets[discr_val as usize])
}
Call { ref func, ref args, ref destination, .. } => {
let mut return_ptr = None;
if let Some((ref lv, target)) = *destination {
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self.frame_mut().next_block = target;
return_ptr = Some(try!(self.eval_lvalue(lv)));
}
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let func_ty = self.operand_ty(func);
match func_ty.sty {
ty::TyFnDef(def_id, substs, fn_ty) => {
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use syntax::abi::Abi;
match fn_ty.abi {
Abi::RustIntrinsic => {
let name = self.tcx.item_name(def_id).as_str();
match fn_ty.sig.0.output {
ty::FnConverging(ty) => {
let size = self.ty_size(ty);
try!(self.call_intrinsic(&name, substs, args,
return_ptr.unwrap(), size))
}
ty::FnDiverging => unimplemented!(),
}
}
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Abi::C =>
try!(self.call_c_abi(def_id, args, return_ptr.unwrap())),
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Abi::Rust | Abi::RustCall => {
// TODO(tsion): Adjust the first argument when calling a Fn or
// FnMut closure via FnOnce::call_once.
// Only trait methods can have a Self parameter.
let (def_id, substs) = if substs.self_ty().is_some() {
self.trait_method(def_id, substs)
} else {
(def_id, substs)
};
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let mut arg_srcs = Vec::new();
for arg in args {
let (src, repr) = try!(self.eval_operand_and_repr(arg));
arg_srcs.push((src, repr.size()));
}
if fn_ty.abi == Abi::RustCall && !args.is_empty() {
arg_srcs.pop();
let last_arg = args.last().unwrap();
let (last_src, last_repr) =
try!(self.eval_operand_and_repr(last_arg));
match *last_repr {
Repr::Aggregate { discr_size: 0, ref variants, .. } => {
assert_eq!(variants.len(), 1);
for field in &variants[0] {
let src = last_src.offset(field.offset as isize);
arg_srcs.push((src, field.size));
}
}
_ => panic!("expected tuple as last argument in function with 'rust-call' ABI"),
}
}
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let mir = self.load_mir(def_id);
self.substs_stack.push(substs);
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try!(self.push_stack_frame(mir, return_ptr));
for (i, (src, size)) in arg_srcs.into_iter().enumerate() {
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let dest = self.frame().locals[i];
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try!(self.memory.copy(src, dest, size));
}
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TerminatorTarget::Call
}
abi => panic!("can't handle function with {:?} ABI", abi),
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}
}
_ => panic!("can't handle callee of type {:?}", func_ty),
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}
}
Drop { target, .. } => {
// TODO: Handle destructors and dynamic drop.
TerminatorTarget::Block(target)
}
Resume => unimplemented!(),
};
Ok(target)
}
fn call_intrinsic(&mut self, name: &str, substs: &'tcx Substs<'tcx>,
args: &[mir::Operand<'tcx>], dest: Pointer, dest_size: usize)
-> EvalResult<TerminatorTarget>
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{
match name {
"assume" => {}
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"copy_nonoverlapping" => {
let elem_ty = *substs.types.get(subst::FnSpace, 0);
let elem_size = self.ty_size(elem_ty);
let src_arg = try!(self.eval_operand(&args[0]));
let dest_arg = try!(self.eval_operand(&args[1]));
let count_arg = try!(self.eval_operand(&args[2]));
let src = try!(self.memory.read_ptr(src_arg));
let dest = try!(self.memory.read_ptr(dest_arg));
let count = try!(self.memory.read_int(count_arg, self.memory.pointer_size));
try!(self.memory.copy(src, dest, count as usize * elem_size));
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}
// TODO(tsion): Mark as dropped?
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"forget" => {}
"min_align_of" => {
try!(self.memory.write_int(dest, 1, dest_size));
}
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"move_val_init" => {
let ty = *substs.types.get(subst::FnSpace, 0);
let size = self.ty_size(ty);
let ptr_arg = try!(self.eval_operand(&args[0]));
let ptr = try!(self.memory.read_ptr(ptr_arg));
let val = try!(self.eval_operand(&args[1]));
try!(self.memory.copy(val, ptr, size));
}
// FIXME(tsion): Handle different integer types correctly.
"mul_with_overflow" => {
let ty = *substs.types.get(subst::FnSpace, 0);
let size = self.ty_size(ty);
let left_arg = try!(self.eval_operand(&args[0]));
let right_arg = try!(self.eval_operand(&args[1]));
let left = try!(self.memory.read_int(left_arg, size));
let right = try!(self.memory.read_int(right_arg, size));
let (n, overflowed) = unsafe {
::std::intrinsics::mul_with_overflow::<i64>(left, right)
};
try!(self.memory.write_int(dest, n, size));
try!(self.memory.write_bool(dest.offset(size as isize), overflowed));
}
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"offset" => {
let pointee_ty = *substs.types.get(subst::FnSpace, 0);
let pointee_size = self.ty_size(pointee_ty) as isize;
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let ptr_arg = try!(self.eval_operand(&args[0]));
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let offset_arg = try!(self.eval_operand(&args[1]));
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let offset = try!(self.memory.read_int(offset_arg, self.memory.pointer_size));
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match self.memory.read_ptr(ptr_arg) {
Ok(ptr) => {
let result_ptr = ptr.offset(offset as isize * pointee_size);
try!(self.memory.write_ptr(dest, result_ptr));
}
Err(EvalError::ReadBytesAsPointer) => {
let psize = self.memory.pointer_size;
let addr = try!(self.memory.read_int(ptr_arg, psize));
let result_addr = addr + offset * pointee_size as i64;
try!(self.memory.write_int(dest, result_addr, psize));
}
Err(e) => return Err(e),
}
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}
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"size_of" => {
let ty = *substs.types.get(subst::FnSpace, 0);
let size = self.ty_size(ty) as u64;
try!(self.memory.write_uint(dest, size, dest_size));
}
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"transmute" => {
let src = try!(self.eval_operand(&args[0]));
try!(self.memory.copy(src, dest, dest_size));
}
// TODO(tsion): Mark bytes as undef.
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"uninit" => {}
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name => panic!("can't handle intrinsic: {}", name),
}
// Since we pushed no stack frame, the main loop will act
// as if the call just completed and it's returning to the
// current frame.
Ok(TerminatorTarget::Call)
}
fn call_c_abi(&mut self, def_id: DefId, args: &[mir::Operand<'tcx>], dest: Pointer)
-> EvalResult<TerminatorTarget>
{
let name = self.tcx.item_name(def_id);
let attrs = self.tcx.get_attrs(def_id);
let link_name = match attr::first_attr_value_str_by_name(&attrs, "link_name") {
Some(ln) => ln.clone(),
None => name.as_str(),
};
match &link_name[..] {
"__rust_allocate" => {
let size_arg = try!(self.eval_operand(&args[0]));
let _align_arg = try!(self.eval_operand(&args[1]));
let size = try!(self.memory.read_uint(size_arg, self.memory.pointer_size));
let ptr = self.memory.allocate(size as usize);
try!(self.memory.write_ptr(dest, ptr));
}
_ => panic!("can't call C ABI function: {}", link_name),
}
// Since we pushed no stack frame, the main loop will act
// as if the call just completed and it's returning to the
// current frame.
Ok(TerminatorTarget::Call)
}
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fn assign_to_aggregate(&mut self, dest: Pointer, dest_repr: &Repr, variant: usize,
operands: &[mir::Operand<'tcx>]) -> EvalResult<()> {
match *dest_repr {
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Repr::Aggregate { discr_size, ref variants, .. } => {
if discr_size > 0 {
let discr = variant as u64;
try!(self.memory.write_uint(dest, discr, discr_size));
}
let after_discr = dest.offset(discr_size as isize);
for (field, operand) in variants[variant].iter().zip(operands) {
let src = try!(self.eval_operand(operand));
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let field_dest = after_discr.offset(field.offset as isize);
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try!(self.memory.copy(src, field_dest, field.size));
}
}
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_ => panic!("expected Repr::Aggregate target"),
}
Ok(())
}
fn eval_assignment(&mut self, lvalue: &mir::Lvalue<'tcx>, rvalue: &mir::Rvalue<'tcx>)
-> EvalResult<()>
{
let dest = try!(self.eval_lvalue(lvalue));
let dest_repr = self.lvalue_repr(lvalue);
use rustc::mir::repr::Rvalue::*;
match *rvalue {
Use(ref operand) => {
let src = try!(self.eval_operand(operand));
self.memory.copy(src, dest, dest_repr.size())
}
BinaryOp(bin_op, ref left, ref right) => {
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let left_ptr = try!(self.eval_operand(left));
let left_ty = self.operand_ty(left);
let left_val = try!(self.read_primval(left_ptr, left_ty));
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let right_ptr = try!(self.eval_operand(right));
let right_ty = self.operand_ty(right);
let right_val = try!(self.read_primval(right_ptr, right_ty));
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let val = try!(primval::binary_op(bin_op, left_val, right_val));
self.memory.write_primval(dest, val)
}
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UnaryOp(un_op, ref operand) => {
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let ptr = try!(self.eval_operand(operand));
let ty = self.operand_ty(operand);
let val = try!(self.read_primval(ptr, ty));
self.memory.write_primval(dest, primval::unary_op(un_op, val))
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}
Aggregate(ref kind, ref operands) => {
use rustc::mir::repr::AggregateKind::*;
match *kind {
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Tuple => self.assign_to_aggregate(dest, &dest_repr, 0, operands),
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Adt(_, variant_idx, _) =>
self.assign_to_aggregate(dest, &dest_repr, variant_idx, operands),
Vec => match *dest_repr {
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Repr::Array { elem_size, length } => {
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assert_eq!(length, operands.len());
for (i, operand) in operands.iter().enumerate() {
let src = try!(self.eval_operand(operand));
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let offset = i * elem_size;
let elem_dest = dest.offset(offset as isize);
try!(self.memory.copy(src, elem_dest, elem_size));
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}
Ok(())
}
_ => panic!("expected Repr::Array target"),
},
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Closure(..) => self.assign_to_aggregate(dest, &dest_repr, 0, operands),
}
}
Len(ref lvalue) => {
let ty = self.lvalue_ty(lvalue);
match ty.sty {
ty::TyArray(_, n) => {
let psize = self.memory.pointer_size;
self.memory.write_uint(dest, n as u64, psize)
}
ty::TySlice(_) => {
unimplemented!()
}
_ => panic!("Rvalue::Len expected array or slice, got {:?}", ty),
}
}
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Ref(_, _, ref lvalue) => {
let ptr = try!(self.eval_lvalue(lvalue));
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self.memory.write_ptr(dest, ptr)
}
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Box(ty) => {
let size = self.ty_size(ty);
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let ptr = self.memory.allocate(size);
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self.memory.write_ptr(dest, ptr)
}
Cast(kind, ref operand, dest_ty) => {
fn pointee_type<'tcx>(ptr_ty: ty::Ty<'tcx>) -> Option<ty::Ty<'tcx>> {
match ptr_ty.sty {
ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
ty::TyRawPtr(ty::TypeAndMut { ty, .. }) |
ty::TyBox(ty) => {
Some(ty)
}
_ => None,
}
}
let src = try!(self.eval_operand(operand));
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let src_ty = self.operand_ty(operand);
use rustc::mir::repr::CastKind::*;
match kind {
Unsize => {
try!(self.memory.copy(src, dest, 8));
let src_pointee_ty = pointee_type(src_ty).unwrap();
let dest_pointee_ty = pointee_type(dest_ty).unwrap();
match (&src_pointee_ty.sty, &dest_pointee_ty.sty) {
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(&ty::TyArray(_, length), &ty::TySlice(_)) => {
let size = self.memory.pointer_size;
self.memory.write_uint(
dest.offset(size as isize),
length as u64,
size,
)
}
_ => panic!("can't handle cast: {:?}", rvalue),
}
}
Misc => {
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// FIXME(tsion): Wrong for almost everything.
let size = dest_repr.size();
self.memory.copy(src, dest, size)
// panic!("can't handle cast: {:?}", rvalue);
}
_ => panic!("can't handle cast: {:?}", rvalue),
}
}
ref r => panic!("can't handle rvalue: {:?}", r),
}
}
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fn operand_ty(&self, operand: &mir::Operand<'tcx>) -> ty::Ty<'tcx> {
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let ty = self.mir().operand_ty(self.tcx, operand);
self.monomorphize(ty)
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}
fn eval_operand(&mut self, op: &mir::Operand<'tcx>) -> EvalResult<Pointer> {
self.eval_operand_and_repr(op).map(|(p, _)| p)
}
fn eval_operand_and_repr(&mut self, op: &mir::Operand<'tcx>)
-> EvalResult<(Pointer, &'arena Repr)>
{
use rustc::mir::repr::Operand::*;
match *op {
Consume(ref lvalue) => Ok((try!(self.eval_lvalue(lvalue)), self.lvalue_repr(lvalue))),
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Constant(mir::Constant { ref literal, ty, .. }) => {
use rustc::mir::repr::Literal::*;
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match *literal {
Value { ref value } => Ok((
try!(self.const_to_ptr(value)),
self.ty_to_repr(ty),
)),
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ref l => panic!("can't handle item literal: {:?}", l),
}
}
}
}
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// TODO(tsion): Replace this inefficient hack with a wrapper like LvalueTy (e.g. LvalueRepr).
fn lvalue_repr(&self, lvalue: &mir::Lvalue<'tcx>) -> &'arena Repr {
use rustc::mir::tcx::LvalueTy;
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match self.mir().lvalue_ty(self.tcx, lvalue) {
LvalueTy::Ty { ty } => self.ty_to_repr(ty),
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LvalueTy::Downcast { ref adt_def, substs, variant_index } => {
let field_tys = adt_def.variants[variant_index].fields.iter()
.map(|f| f.ty(self.tcx, substs));
self.repr_arena.alloc(self.make_aggregate_repr(iter::once(field_tys)))
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}
}
}
fn eval_lvalue(&mut self, lvalue: &mir::Lvalue<'tcx>) -> EvalResult<Pointer> {
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use rustc::mir::repr::Lvalue::*;
let ptr = match *lvalue {
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ReturnPointer => self.frame().return_ptr
.expect("ReturnPointer used in a function with no return value"),
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Arg(i) => self.frame().locals[i as usize],
Var(i) => self.frame().locals[self.frame().var_offset + i as usize],
Temp(i) => self.frame().locals[self.frame().temp_offset + i as usize],
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Projection(ref proj) => {
let base_ptr = try!(self.eval_lvalue(&proj.base));
let base_repr = self.lvalue_repr(&proj.base);
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use rustc::mir::repr::ProjectionElem::*;
match proj.elem {
Field(field, _) => match *base_repr {
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Repr::Aggregate { discr_size: 0, ref variants, .. } => {
let fields = &variants[0];
base_ptr.offset(fields[field.index()].offset as isize)
}
_ => panic!("field access on non-product type: {:?}", base_repr),
},
Downcast(..) => match *base_repr {
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Repr::Aggregate { discr_size, .. } => base_ptr.offset(discr_size as isize),
_ => panic!("variant downcast on non-aggregate type: {:?}", base_repr),
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},
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// FIXME(tsion): Wrong for fat pointers.
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Deref => try!(self.memory.read_ptr(base_ptr)),
Index(ref operand) => {
let base_ty = self.lvalue_ty(&proj.base);
let elem_size = match base_ty.sty {
ty::TyArray(elem_ty, _) => self.ty_size(elem_ty),
ty::TySlice(elem_ty) => self.ty_size(elem_ty),
_ => panic!("indexing expected an array or slice, got {:?}", base_ty),
};
let n_ptr = try!(self.eval_operand(operand));
let n = try!(self.memory.read_uint(n_ptr, self.memory.pointer_size));
base_ptr.offset(n as isize * elem_size as isize)
}
ref p => panic!("can't handle lvalue projection: {:?}", p),
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}
}
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ref l => panic!("can't handle lvalue: {:?}", l),
};
Ok(ptr)
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}
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// TODO(tsion): Try making const_to_primval instead.
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fn const_to_ptr(&mut self, const_val: &const_eval::ConstVal) -> EvalResult<Pointer> {
use rustc::middle::const_eval::ConstVal::*;
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match *const_val {
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Float(_f) => unimplemented!(),
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Integral(int) => {
// TODO(tsion): Check int constant type.
let ptr = self.memory.allocate(8);
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try!(self.memory.write_uint(ptr, int.to_u64_unchecked(), 8));
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Ok(ptr)
}
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Str(ref s) => {
let psize = self.memory.pointer_size;
let static_ptr = self.memory.allocate(s.len());
let ptr = self.memory.allocate(psize * 2);
try!(self.memory.write_bytes(static_ptr, s.as_bytes()));
try!(self.memory.write_ptr(ptr, static_ptr));
try!(self.memory.write_uint(ptr.offset(psize as isize), s.len() as u64, psize));
Ok(ptr)
}
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ByteStr(ref bs) => {
let psize = self.memory.pointer_size;
let static_ptr = self.memory.allocate(bs.len());
let ptr = self.memory.allocate(psize);
try!(self.memory.write_bytes(static_ptr, bs));
try!(self.memory.write_ptr(ptr, static_ptr));
Ok(ptr)
}
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Bool(b) => {
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let ptr = self.memory.allocate(1);
try!(self.memory.write_bool(ptr, b));
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Ok(ptr)
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}
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Char(_c) => unimplemented!(),
Struct(_node_id) => unimplemented!(),
Tuple(_node_id) => unimplemented!(),
Function(_def_id) => unimplemented!(),
Array(_, _) => unimplemented!(),
Repeat(_, _) => unimplemented!(),
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Dummy => unimplemented!(),
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}
}
fn lvalue_ty(&self, lvalue: &mir::Lvalue<'tcx>) -> ty::Ty<'tcx> {
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self.mir().lvalue_ty(self.tcx, lvalue).to_ty(self.tcx)
}
fn monomorphize(&self, ty: ty::Ty<'tcx>) -> ty::Ty<'tcx> {
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let substituted = ty.subst(self.tcx, self.substs());
infer::normalize_associated_type(self.tcx, &substituted)
}
fn type_is_sized(&self, ty: ty::Ty<'tcx>) -> bool {
ty.is_sized(&self.tcx.empty_parameter_environment(), DUMMY_SP)
}
fn ty_size(&self, ty: ty::Ty<'tcx>) -> usize {
self.ty_to_repr(ty).size()
}
fn ty_to_repr(&self, ty: ty::Ty<'tcx>) -> &'arena Repr {
let ty = self.monomorphize(ty);
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if let Some(repr) = self.repr_cache.borrow().get(ty) {
return repr;
}
use syntax::ast::{IntTy, UintTy};
let repr = match ty.sty {
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ty::TyBool => Repr::Primitive { size: 1 },
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ty::TyInt(IntTy::I8) | ty::TyUint(UintTy::U8) => Repr::Primitive { size: 1 },
ty::TyInt(IntTy::I16) | ty::TyUint(UintTy::U16) => Repr::Primitive { size: 2 },
ty::TyInt(IntTy::I32) | ty::TyUint(UintTy::U32) => Repr::Primitive { size: 4 },
ty::TyInt(IntTy::I64) | ty::TyUint(UintTy::U64) => Repr::Primitive { size: 8 },
ty::TyInt(IntTy::Is) | ty::TyUint(UintTy::Us) =>
Repr::Primitive { size: self.memory.pointer_size },
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ty::TyTuple(ref fields) =>
self.make_aggregate_repr(iter::once(fields.iter().cloned())),
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ty::TyEnum(adt_def, substs) | ty::TyStruct(adt_def, substs) => {
let variants = adt_def.variants.iter().map(|v| {
v.fields.iter().map(|f| f.ty(self.tcx, substs))
});
self.make_aggregate_repr(variants)
}
ty::TyArray(elem_ty, length) => Repr::Array {
elem_size: self.ty_size(elem_ty),
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length: length,
},
ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
ty::TyRawPtr(ty::TypeAndMut { ty, .. }) |
ty::TyBox(ty) => {
if self.type_is_sized(ty) {
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Repr::Primitive { size: self.memory.pointer_size }
} else {
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Repr::Primitive { size: self.memory.pointer_size * 2 }
}
}
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ty::TyFnPtr(..) => Repr::Primitive { size: self.memory.pointer_size },
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ty::TyClosure(_, ref closure_substs) =>
self.make_aggregate_repr(iter::once(closure_substs.upvar_tys.iter().cloned())),
ref t => panic!("can't convert type to repr: {:?}", t),
};
let repr_ref = self.repr_arena.alloc(repr);
self.repr_cache.borrow_mut().insert(ty, repr_ref);
repr_ref
}
fn make_aggregate_repr<V>(&self, variant_fields: V) -> Repr
where V: IntoIterator, V::Item: IntoIterator<Item = ty::Ty<'tcx>>
{
let mut variants = Vec::new();
let mut max_variant_size = 0;
for field_tys in variant_fields {
let mut fields = Vec::new();
let mut size = 0;
for ty in field_tys {
let field_size = self.ty_size(ty);
let offest = size;
size += field_size;
fields.push(FieldRepr { offset: offest, size: field_size });
}
if size > max_variant_size { max_variant_size = size; }
variants.push(fields);
}
let discr_size = match variants.len() {
n if n <= 1 => 0,
n if n <= 1 << 8 => 1,
n if n <= 1 << 16 => 2,
n if n <= 1 << 32 => 4,
_ => 8,
};
Repr::Aggregate {
discr_size: discr_size,
size: max_variant_size + discr_size,
variants: variants,
}
}
pub fn read_primval(&mut self, ptr: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<PrimVal> {
use syntax::ast::{IntTy, UintTy};
let val = match ty.sty {
ty::TyBool => PrimVal::Bool(try!(self.memory.read_bool(ptr))),
ty::TyInt(IntTy::I8) => PrimVal::I8(try!(self.memory.read_int(ptr, 1)) as i8),
ty::TyInt(IntTy::I16) => PrimVal::I16(try!(self.memory.read_int(ptr, 2)) as i16),
ty::TyInt(IntTy::I32) => PrimVal::I32(try!(self.memory.read_int(ptr, 4)) as i32),
ty::TyInt(IntTy::I64) => PrimVal::I64(try!(self.memory.read_int(ptr, 8)) as i64),
ty::TyUint(UintTy::U8) => PrimVal::U8(try!(self.memory.read_uint(ptr, 1)) as u8),
ty::TyUint(UintTy::U16) => PrimVal::U16(try!(self.memory.read_uint(ptr, 2)) as u16),
ty::TyUint(UintTy::U32) => PrimVal::U32(try!(self.memory.read_uint(ptr, 4)) as u32),
ty::TyUint(UintTy::U64) => PrimVal::U64(try!(self.memory.read_uint(ptr, 8)) as u64),
// TODO(tsion): Pick the PrimVal dynamically.
ty::TyInt(IntTy::Is) =>
PrimVal::I64(try!(self.memory.read_int(ptr, self.memory.pointer_size))),
ty::TyUint(UintTy::Us) =>
PrimVal::U64(try!(self.memory.read_uint(ptr, self.memory.pointer_size))),
ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
ty::TyRawPtr(ty::TypeAndMut { ty, .. }) => {
if self.type_is_sized(ty) {
match self.memory.read_ptr(ptr) {
Ok(p) => PrimVal::AbstractPtr(p),
Err(EvalError::ReadBytesAsPointer) => {
let n = try!(self.memory.read_uint(ptr, self.memory.pointer_size));
PrimVal::IntegerPtr(n)
}
Err(e) => return Err(e),
}
} else {
panic!("unimplemented: primitive read of fat pointer type: {:?}", ty);
}
}
_ => panic!("primitive read of non-primitive type: {:?}", ty),
};
Ok(val)
}
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fn frame(&self) -> &Frame<'a, 'tcx> {
self.stack.last().expect("no call frames exist")
}
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fn frame_mut(&mut self) -> &mut Frame<'a, 'tcx> {
self.stack.last_mut().expect("no call frames exist")
}
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fn mir(&self) -> &mir::Mir<'tcx> {
&self.frame().mir
}
fn substs(&self) -> &'tcx Substs<'tcx> {
self.substs_stack.last().cloned().unwrap_or_else(|| self.tcx.mk_substs(Substs::empty()))
}
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fn load_mir(&self, def_id: DefId) -> CachedMir<'a, 'tcx> {
match self.tcx.map.as_local_node_id(def_id) {
Some(node_id) => CachedMir::Ref(self.mir_map.map.get(&node_id).unwrap()),
None => {
let mut mir_cache = self.mir_cache.borrow_mut();
if let Some(mir) = mir_cache.get(&def_id) {
return CachedMir::Owned(mir.clone());
}
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use rustc::middle::cstore::CrateStore;
let cs = &self.tcx.sess.cstore;
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let mir = cs.maybe_get_item_mir(self.tcx, def_id).unwrap_or_else(|| {
panic!("no mir for {:?}", def_id);
});
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let cached = Rc::new(mir);
mir_cache.insert(def_id, cached.clone());
CachedMir::Owned(cached)
}
}
}
fn fulfill_obligation(&self, trait_ref: ty::PolyTraitRef<'tcx>) -> traits::Vtable<'tcx, ()> {
// Do the initial selection for the obligation. This yields the shallow result we are
// looking for -- that is, what specific impl.
let infcx = infer::normalizing_infer_ctxt(self.tcx, &self.tcx.tables);
let mut selcx = traits::SelectionContext::new(&infcx);
let obligation = traits::Obligation::new(
traits::ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID),
trait_ref.to_poly_trait_predicate(),
);
let selection = selcx.select(&obligation).unwrap().unwrap();
// Currently, we use a fulfillment context to completely resolve all nested obligations.
// This is because they can inform the inference of the impl's type parameters.
let mut fulfill_cx = traits::FulfillmentContext::new();
let vtable = selection.map(|predicate| {
fulfill_cx.register_predicate_obligation(&infcx, predicate);
});
let vtable = infer::drain_fulfillment_cx_or_panic(
DUMMY_SP, &infcx, &mut fulfill_cx, &vtable
);
vtable
}
/// Trait method, which has to be resolved to an impl method.
pub fn trait_method(&self, def_id: DefId, substs: &'tcx Substs<'tcx>)
-> (DefId, &'tcx Substs<'tcx>) {
let method_item = self.tcx.impl_or_trait_item(def_id);
let trait_id = method_item.container().id();
let trait_ref = ty::Binder(substs.to_trait_ref(self.tcx, trait_id));
match self.fulfill_obligation(trait_ref) {
traits::VtableImpl(vtable_impl) => {
let impl_did = vtable_impl.impl_def_id;
let mname = self.tcx.item_name(def_id);
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// Create a concatenated set of substitutions which includes those from the impl
// and those from the method:
let impl_substs = vtable_impl.substs.with_method_from(substs);
let substs = self.tcx.mk_substs(impl_substs);
let mth = self.tcx.get_impl_method(impl_did, substs, mname);
(mth.method.def_id, mth.substs)
}
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traits::VtableClosure(vtable_closure) =>
(vtable_closure.closure_def_id, vtable_closure.substs.func_substs),
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traits::VtableFnPointer(_fn_ty) => {
let _trait_closure_kind = self.tcx.lang_items.fn_trait_kind(trait_id).unwrap();
unimplemented!()
// let llfn = trans_fn_pointer_shim(ccx, trait_closure_kind, fn_ty);
// let method_ty = def_ty(tcx, def_id, substs);
// let fn_ptr_ty = match method_ty.sty {
// ty::TyFnDef(_, _, fty) => tcx.mk_ty(ty::TyFnPtr(fty)),
// _ => unreachable!("expected fn item type, found {}",
// method_ty)
// };
// Callee::ptr(immediate_rvalue(llfn, fn_ptr_ty))
}
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traits::VtableObject(ref _data) => {
unimplemented!()
// Callee {
// data: Virtual(traits::get_vtable_index_of_object_method(
// tcx, data, def_id)),
// ty: def_ty(tcx, def_id, substs)
// }
}
vtable => unreachable!("resolved vtable bad vtable {:?} in trans", vtable),
}
}
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}
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impl<'mir, 'tcx: 'mir> Deref for CachedMir<'mir, 'tcx> {
type Target = mir::Mir<'tcx>;
fn deref(&self) -> &mir::Mir<'tcx> {
match *self {
CachedMir::Ref(r) => r,
CachedMir::Owned(ref rc) => &rc,
}
}
}
pub fn interpret_start_points<'tcx>(tcx: &TyCtxt<'tcx>, mir_map: &MirMap<'tcx>) {
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/// Print the given allocation and all allocations it depends on.
fn print_allocation_tree(memory: &Memory, alloc_id: memory::AllocId) {
let alloc = memory.get(alloc_id).unwrap();
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println!(" {:?}: {:?}", alloc_id, alloc);
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for &target_alloc in alloc.relocations.values() {
print_allocation_tree(memory, target_alloc);
}
}
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for (&id, mir) in &mir_map.map {
for attr in tcx.map.attrs(id) {
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use syntax::attr::AttrMetaMethods;
if attr.check_name("miri_run") {
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let item = tcx.map.expect_item(id);
println!("Interpreting: {}", item.name);
let repr_arena = TypedArena::new();
let mut miri = Interpreter::new(tcx, mir_map, &repr_arena);
let return_ptr = match mir.return_ty {
ty::FnConverging(ty) => {
let size = miri.ty_size(ty);
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Some(miri.memory.allocate(size))
}
ty::FnDiverging => None,
};
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miri.push_stack_frame(CachedMir::Ref(mir), return_ptr).unwrap();
miri.run().unwrap();
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if let Some(ret) = return_ptr {
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println!("Result:");
print_allocation_tree(&miri.memory, ret.alloc_id);
println!("");
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}
}
}
}
}