2 use rustc::middle::const_val;
3 use rustc::hir::def_id::DefId;
4 use rustc::mir::mir_map::MirMap;
5 use rustc::mir::repr as mir;
6 use rustc::traits::{self, ProjectionMode};
7 use rustc::ty::fold::TypeFoldable;
8 use rustc::ty::layout::{self, Layout, Size};
9 use rustc::ty::subst::{self, Subst, Substs};
10 use rustc::ty::{self, TyCtxt};
11 use rustc::util::nodemap::DefIdMap;
12 use std::cell::RefCell;
18 use syntax::codemap::{self, DUMMY_SP};
20 use error::{EvalError, EvalResult};
21 use memory::{Memory, Pointer};
22 use primval::{self, PrimVal};
24 const TRACE_EXECUTION: bool = false;
26 struct Interpreter<'a, 'tcx: 'a> {
27 /// The results of the type checker, from rustc.
28 tcx: &'a TyCtxt<'tcx>,
30 /// A mapping from NodeIds to Mir, from rustc. Only contains MIR for crate-local items.
31 mir_map: &'a MirMap<'tcx>,
33 /// A local cache from DefIds to Mir for non-crate-local items.
34 mir_cache: RefCell<DefIdMap<Rc<mir::Mir<'tcx>>>>,
36 /// The virtual memory system.
39 /// The virtual call stack.
40 stack: Vec<Frame<'a, 'tcx>>,
42 /// Another stack containing the type substitutions for the current function invocation. It
43 /// exists separately from `stack` because it must contain the `Substs` for a function while
44 /// *creating* the `Frame` for that same function.
45 substs_stack: Vec<&'tcx Substs<'tcx>>,
47 // TODO(tsion): Merge with `substs_stack`. Also try restructuring `Frame` to accomodate.
48 /// A stack of the things necessary to print good strack traces:
49 /// * Function DefIds and Substs to print proper substituted function names.
50 /// * Spans pointing to specific function calls in the source.
51 name_stack: Vec<(DefId, &'tcx Substs<'tcx>, codemap::Span)>,
55 struct Frame<'a, 'tcx: 'a> {
56 /// The MIR for the function called on this frame.
57 mir: CachedMir<'a, 'tcx>,
59 /// The block this frame will execute when a function call returns back to this frame.
60 next_block: mir::BasicBlock,
62 /// A pointer for writing the return value of the current call if it's not a diverging call.
63 return_ptr: Option<Pointer>,
65 /// The list of locals for the current function, stored in order as
66 /// `[arguments..., variables..., temporaries...]`. The variables begin at `self.var_offset`
67 /// and the temporaries at `self.temp_offset`.
70 /// The offset of the first variable in `self.locals`.
73 /// The offset of the first temporary in `self.locals`.
77 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
83 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
87 // TODO(tsion): Vtable(memory::AllocId),
88 DowncastVariant(usize),
92 enum CachedMir<'mir, 'tcx: 'mir> {
93 Ref(&'mir mir::Mir<'tcx>),
94 Owned(Rc<mir::Mir<'tcx>>)
97 /// Represents the action to be taken in the main loop as a result of executing a terminator.
98 enum TerminatorTarget {
99 /// Make a local jump to the given block.
100 Block(mir::BasicBlock),
102 /// Start executing from the new current frame. (For function calls.)
105 /// Stop executing the current frame and resume the previous frame.
109 impl<'a, 'tcx: 'a> Interpreter<'a, 'tcx> {
110 fn new(tcx: &'a TyCtxt<'tcx>, mir_map: &'a MirMap<'tcx>) -> Self {
114 mir_cache: RefCell::new(DefIdMap()),
115 memory: Memory::new(),
117 substs_stack: Vec::new(),
118 name_stack: Vec::new(),
122 fn maybe_report<T>(&self, span: codemap::Span, r: EvalResult<T>) -> EvalResult<T> {
123 if let Err(ref e) = r {
124 let mut err = self.tcx.sess.struct_span_err(span, &e.to_string());
125 for &(def_id, substs, span) in self.name_stack.iter().rev() {
126 // FIXME(tsion): Find a way to do this without this Display impl hack.
127 use rustc::util::ppaux;
129 struct Instance<'tcx>(DefId, &'tcx Substs<'tcx>);
130 impl<'tcx> fmt::Display for Instance<'tcx> {
131 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
132 ppaux::parameterized(f, self.1, self.0, ppaux::Ns::Value, &[],
133 |tcx| tcx.lookup_item_type(self.0).generics)
136 err.span_note(span, &format!("inside call to {}", Instance(def_id, substs)));
143 fn log<F>(&self, extra_indent: usize, f: F) where F: FnOnce() {
144 let indent = self.stack.len() + extra_indent;
145 if !TRACE_EXECUTION { return; }
146 for _ in 0..indent { print!(" "); }
151 fn run(&mut self) -> EvalResult<()> {
152 'outer: while !self.stack.is_empty() {
153 let mut current_block = self.frame().next_block;
156 self.log(0, || print!("// {:?}", current_block));
157 let current_mir = self.mir().clone(); // Cloning a reference.
158 let block_data = current_mir.basic_block_data(current_block);
160 for stmt in &block_data.statements {
161 self.log(0, || print!("{:?}", stmt));
162 let mir::StatementKind::Assign(ref lvalue, ref rvalue) = stmt.kind;
163 let result = self.eval_assignment(lvalue, rvalue);
164 try!(self.maybe_report(stmt.span, result));
167 let terminator = block_data.terminator();
168 self.log(0, || print!("{:?}", terminator.kind));
170 let result = self.eval_terminator(terminator);
171 match try!(self.maybe_report(terminator.span, result)) {
172 TerminatorTarget::Block(block) => current_block = block,
173 TerminatorTarget::Return => {
174 self.pop_stack_frame();
175 self.name_stack.pop();
178 TerminatorTarget::Call => continue 'outer,
186 fn push_stack_frame(&mut self, mir: CachedMir<'a, 'tcx>, substs: &'tcx Substs<'tcx>,
187 return_ptr: Option<Pointer>)
189 self.substs_stack.push(substs);
191 let arg_tys = mir.arg_decls.iter().map(|a| a.ty);
192 let var_tys = mir.var_decls.iter().map(|v| v.ty);
193 let temp_tys = mir.temp_decls.iter().map(|t| t.ty);
195 let locals: Vec<Pointer> = arg_tys.chain(var_tys).chain(temp_tys).map(|ty| {
196 let size = self.type_size(ty);
197 self.memory.allocate(size)
200 let num_args = mir.arg_decls.len();
201 let num_vars = mir.var_decls.len();
203 self.stack.push(Frame {
205 next_block: mir::START_BLOCK,
206 return_ptr: return_ptr,
208 var_offset: num_args,
209 temp_offset: num_args + num_vars,
213 fn pop_stack_frame(&mut self) {
214 let _frame = self.stack.pop().expect("tried to pop a stack frame, but there were none");
215 // TODO(tsion): Deallocate local variables.
216 self.substs_stack.pop();
219 fn eval_terminator(&mut self, terminator: &mir::Terminator<'tcx>)
220 -> EvalResult<TerminatorTarget> {
221 use rustc::mir::repr::TerminatorKind::*;
222 let target = match terminator.kind {
223 Return => TerminatorTarget::Return,
225 Goto { target } => TerminatorTarget::Block(target),
227 If { ref cond, targets: (then_target, else_target) } => {
228 let cond_ptr = try!(self.eval_operand(cond));
229 let cond_val = try!(self.memory.read_bool(cond_ptr));
230 TerminatorTarget::Block(if cond_val { then_target } else { else_target })
233 SwitchInt { ref discr, ref values, ref targets, .. } => {
234 let discr_ptr = try!(self.eval_lvalue(discr)).to_ptr();
235 let discr_size = self
236 .type_layout(self.lvalue_ty(discr))
237 .size(&self.tcx.data_layout)
239 let discr_val = try!(self.memory.read_uint(discr_ptr, discr_size));
241 // Branch to the `otherwise` case by default, if no match is found.
242 let mut target_block = targets[targets.len() - 1];
244 for (index, val_const) in values.iter().enumerate() {
245 let ptr = try!(self.const_to_ptr(val_const));
246 let val = try!(self.memory.read_uint(ptr, discr_size));
247 if discr_val == val {
248 target_block = targets[index];
253 TerminatorTarget::Block(target_block)
256 Switch { ref discr, ref targets, adt_def } => {
257 let adt_ptr = try!(self.eval_lvalue(discr)).to_ptr();
258 let adt_layout = self.type_layout(self.lvalue_ty(discr));
261 Layout::General { discr, .. } | Layout::CEnum { discr, .. } => {
262 let discr_size = discr.size().bytes();
263 let discr_val = try!(self.memory.read_uint(adt_ptr, discr_size as usize));
265 let matching = adt_def.variants.iter()
266 .position(|v| discr_val == v.disr_val.to_u64_unchecked());
269 Some(i) => TerminatorTarget::Block(targets[i]),
270 None => return Err(EvalError::InvalidDiscriminant),
274 Layout::RawNullablePointer { nndiscr, .. } => {
275 let is_null = match self.memory.read_usize(adt_ptr) {
277 Ok(_) | Err(EvalError::ReadPointerAsBytes) => false,
278 Err(e) => return Err(e),
281 assert!(nndiscr == 0 || nndiscr == 1);
282 let target = if is_null { 1 - nndiscr } else { nndiscr };
283 TerminatorTarget::Block(targets[target as usize])
286 _ => panic!("attempted to switch on non-aggregate type"),
290 Call { ref func, ref args, ref destination, .. } => {
291 let mut return_ptr = None;
292 if let Some((ref lv, target)) = *destination {
293 self.frame_mut().next_block = target;
294 return_ptr = Some(try!(self.eval_lvalue(lv)).to_ptr());
297 let func_ty = self.operand_ty(func);
299 ty::TyFnDef(def_id, substs, fn_ty) => {
300 use syntax::abi::Abi;
302 Abi::RustIntrinsic => {
303 let name = self.tcx.item_name(def_id).as_str();
304 match fn_ty.sig.0.output {
305 ty::FnConverging(ty) => {
306 let size = self.type_size(ty);
307 try!(self.call_intrinsic(&name, substs, args,
308 return_ptr.unwrap(), size))
310 ty::FnDiverging => unimplemented!(),
315 try!(self.call_c_abi(def_id, args, return_ptr.unwrap())),
317 Abi::Rust | Abi::RustCall => {
318 // TODO(tsion): Adjust the first argument when calling a Fn or
319 // FnMut closure via FnOnce::call_once.
321 // Only trait methods can have a Self parameter.
322 let (resolved_def_id, resolved_substs) = if substs.self_ty().is_some() {
323 self.trait_method(def_id, substs)
328 let mut arg_srcs = Vec::new();
330 let src = try!(self.eval_operand(arg));
331 let src_ty = self.operand_ty(arg);
332 arg_srcs.push((src, src_ty));
335 if fn_ty.abi == Abi::RustCall && !args.is_empty() {
337 let last_arg = args.last().unwrap();
338 let last = try!(self.eval_operand(last_arg));
339 let last_ty = self.operand_ty(last_arg);
340 let last_layout = self.type_layout(last_ty);
341 match (&last_ty.sty, last_layout) {
342 (&ty::TyTuple(ref fields),
343 &Layout::Univariant { ref variant, .. }) => {
344 let offsets = iter::once(0)
345 .chain(variant.offset_after_field.iter()
346 .map(|s| s.bytes()));
347 for (offset, ty) in offsets.zip(fields) {
348 let src = last.offset(offset as isize);
349 arg_srcs.push((src, ty));
352 ty => panic!("expected tuple as last argument in function with 'rust-call' ABI, got {:?}", ty),
356 let mir = self.load_mir(resolved_def_id);
357 self.name_stack.push((def_id, substs, terminator.span));
358 self.push_stack_frame(mir, resolved_substs, return_ptr);
360 for (i, (src, src_ty)) in arg_srcs.into_iter().enumerate() {
361 let dest = self.frame().locals[i];
362 try!(self.move_(src, dest, src_ty));
365 TerminatorTarget::Call
368 abi => panic!("can't handle function with {:?} ABI", abi),
372 _ => panic!("can't handle callee of type {:?}", func_ty),
376 Drop { ref value, target, .. } => {
377 let ptr = try!(self.eval_lvalue(value)).to_ptr();
378 let ty = self.lvalue_ty(value);
379 try!(self.drop(ptr, ty));
380 TerminatorTarget::Block(target)
383 Resume => unimplemented!(),
389 fn drop(&mut self, ptr: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<()> {
390 if !self.type_needs_drop(ty) {
391 self.log(1, || print!("no need to drop {:?}", ty));
394 self.log(1, || print!("need to drop {:?}", ty));
396 // TODO(tsion): Call user-defined Drop::drop impls.
399 ty::TyBox(contents_ty) => {
400 match self.memory.read_ptr(ptr) {
401 Ok(contents_ptr) => {
402 try!(self.drop(contents_ptr, contents_ty));
403 self.log(1, || print!("deallocating box"));
404 try!(self.memory.deallocate(contents_ptr));
406 Err(EvalError::ReadBytesAsPointer) => {
407 let size = self.memory.pointer_size;
408 let possible_drop_fill = try!(self.memory.read_bytes(ptr, size));
409 if possible_drop_fill.iter().all(|&b| b == mem::POST_DROP_U8) {
412 return Err(EvalError::ReadBytesAsPointer);
415 Err(e) => return Err(e),
419 // TODO(tsion): Implement drop for other relevant types (e.g. aggregates).
424 // FIXME(tsion): Trait objects (with no static size) probably get filled, too.
425 let size = self.type_size(ty);
426 try!(self.memory.drop_fill(ptr, size));
434 substs: &'tcx Substs<'tcx>,
435 args: &[mir::Operand<'tcx>],
438 ) -> EvalResult<TerminatorTarget> {
439 let args_res: EvalResult<Vec<Pointer>> = args.iter()
440 .map(|arg| self.eval_operand(arg))
442 let args = try!(args_res);
447 "copy_nonoverlapping" => {
448 let elem_ty = *substs.types.get(subst::FnSpace, 0);
449 let elem_size = self.type_size(elem_ty);
450 let src = try!(self.memory.read_ptr(args[0]));
451 let dest = try!(self.memory.read_ptr(args[1]));
452 let count = try!(self.memory.read_isize(args[2]));
453 try!(self.memory.copy(src, dest, count as usize * elem_size));
457 let arg_ty = *substs.types.get(subst::FnSpace, 0);
458 let arg_size = self.type_size(arg_ty);
459 try!(self.memory.drop_fill(args[0], arg_size));
462 "init" => try!(self.memory.write_repeat(dest, 0, dest_size)),
465 try!(self.memory.write_int(dest, 1, dest_size));
469 let ty = *substs.types.get(subst::FnSpace, 0);
470 let ptr = try!(self.memory.read_ptr(args[0]));
471 try!(self.move_(args[1], ptr, ty));
474 // FIXME(tsion): Handle different integer types correctly.
475 "add_with_overflow" => {
476 let ty = *substs.types.get(subst::FnSpace, 0);
477 let size = self.type_size(ty);
478 let left = try!(self.memory.read_int(args[0], size));
479 let right = try!(self.memory.read_int(args[1], size));
480 let (n, overflowed) = unsafe {
481 ::std::intrinsics::add_with_overflow::<i64>(left, right)
483 try!(self.memory.write_int(dest, n, size));
484 try!(self.memory.write_bool(dest.offset(size as isize), overflowed));
487 // FIXME(tsion): Handle different integer types correctly.
488 "mul_with_overflow" => {
489 let ty = *substs.types.get(subst::FnSpace, 0);
490 let size = self.type_size(ty);
491 let left = try!(self.memory.read_int(args[0], size));
492 let right = try!(self.memory.read_int(args[1], size));
493 let (n, overflowed) = unsafe {
494 ::std::intrinsics::mul_with_overflow::<i64>(left, right)
496 try!(self.memory.write_int(dest, n, size));
497 try!(self.memory.write_bool(dest.offset(size as isize), overflowed));
501 let pointee_ty = *substs.types.get(subst::FnSpace, 0);
502 let pointee_size = self.type_size(pointee_ty) as isize;
503 let ptr_arg = args[0];
504 let offset = try!(self.memory.read_isize(args[1]));
506 match self.memory.read_ptr(ptr_arg) {
508 let result_ptr = ptr.offset(offset as isize * pointee_size);
509 try!(self.memory.write_ptr(dest, result_ptr));
511 Err(EvalError::ReadBytesAsPointer) => {
512 let addr = try!(self.memory.read_isize(ptr_arg));
513 let result_addr = addr + offset * pointee_size as i64;
514 try!(self.memory.write_isize(dest, result_addr));
516 Err(e) => return Err(e),
520 // FIXME(tsion): Handle different integer types correctly. Use primvals?
521 "overflowing_sub" => {
522 let ty = *substs.types.get(subst::FnSpace, 0);
523 let size = self.type_size(ty);
524 let left = try!(self.memory.read_int(args[0], size));
525 let right = try!(self.memory.read_int(args[1], size));
526 let n = left.wrapping_sub(right);
527 try!(self.memory.write_int(dest, n, size));
531 let ty = *substs.types.get(subst::FnSpace, 0);
532 let size = self.type_size(ty) as u64;
533 try!(self.memory.write_uint(dest, size, dest_size));
537 let ty = *substs.types.get(subst::FnSpace, 0);
538 try!(self.move_(args[0], dest, ty));
540 "uninit" => try!(self.memory.mark_definedness(dest, dest_size, false)),
542 name => panic!("can't handle intrinsic: {}", name),
545 // Since we pushed no stack frame, the main loop will act
546 // as if the call just completed and it's returning to the
548 Ok(TerminatorTarget::Call)
554 args: &[mir::Operand<'tcx>],
556 ) -> EvalResult<TerminatorTarget> {
557 let name = self.tcx.item_name(def_id);
558 let attrs = self.tcx.get_attrs(def_id);
559 let link_name = match attr::first_attr_value_str_by_name(&attrs, "link_name") {
560 Some(ln) => ln.clone(),
561 None => name.as_str(),
564 let args_res: EvalResult<Vec<Pointer>> = args.iter()
565 .map(|arg| self.eval_operand(arg))
567 let args = try!(args_res);
569 match &link_name[..] {
570 "__rust_allocate" => {
571 let size = try!(self.memory.read_usize(args[0]));
572 let ptr = self.memory.allocate(size as usize);
573 try!(self.memory.write_ptr(dest, ptr));
576 "__rust_reallocate" => {
577 let ptr = try!(self.memory.read_ptr(args[0]));
578 let size = try!(self.memory.read_usize(args[2]));
579 try!(self.memory.reallocate(ptr, size as usize));
580 try!(self.memory.write_ptr(dest, ptr));
583 _ => panic!("can't call C ABI function: {}", link_name),
586 // Since we pushed no stack frame, the main loop will act
587 // as if the call just completed and it's returning to the
589 Ok(TerminatorTarget::Call)
592 fn assign_fields<I: IntoIterator<Item = u64>>(
596 operands: &[mir::Operand<'tcx>],
597 ) -> EvalResult<()> {
598 for (offset, operand) in offsets.into_iter().zip(operands) {
599 let src = try!(self.eval_operand(operand));
600 let src_ty = self.operand_ty(operand);
601 let field_dest = dest.offset(offset as isize);
602 try!(self.move_(src, field_dest, src_ty));
607 fn eval_assignment(&mut self, lvalue: &mir::Lvalue<'tcx>, rvalue: &mir::Rvalue<'tcx>)
610 let dest = try!(self.eval_lvalue(lvalue)).to_ptr();
611 let dest_ty = self.lvalue_ty(lvalue);
612 let dest_layout = self.type_layout(dest_ty);
614 use rustc::mir::repr::Rvalue::*;
616 Use(ref operand) => {
617 let src = try!(self.eval_operand(operand));
618 try!(self.move_(src, dest, dest_ty));
621 BinaryOp(bin_op, ref left, ref right) => {
622 let left_ptr = try!(self.eval_operand(left));
623 let left_ty = self.operand_ty(left);
624 let left_val = try!(self.read_primval(left_ptr, left_ty));
626 let right_ptr = try!(self.eval_operand(right));
627 let right_ty = self.operand_ty(right);
628 let right_val = try!(self.read_primval(right_ptr, right_ty));
630 let val = try!(primval::binary_op(bin_op, left_val, right_val));
631 try!(self.memory.write_primval(dest, val));
634 UnaryOp(un_op, ref operand) => {
635 let ptr = try!(self.eval_operand(operand));
636 let ty = self.operand_ty(operand);
637 let val = try!(self.read_primval(ptr, ty));
638 try!(self.memory.write_primval(dest, primval::unary_op(un_op, val)));
641 Aggregate(ref kind, ref operands) => {
642 use rustc::ty::layout::Layout::*;
644 Univariant { ref variant, .. } => {
645 let offsets = iter::once(0)
646 .chain(variant.offset_after_field.iter().map(|s| s.bytes()));
647 try!(self.assign_fields(dest, offsets, operands));
651 let elem_size = match dest_ty.sty {
652 ty::TyArray(elem_ty, _) => self.type_size(elem_ty) as u64,
653 _ => panic!("tried to assign {:?} to non-array type {:?}",
656 let offsets = (0..).map(|i| i * elem_size);
657 try!(self.assign_fields(dest, offsets, operands));
660 General { discr, ref variants, .. } => {
661 if let mir::AggregateKind::Adt(adt_def, variant, _) = *kind {
662 let discr_val = adt_def.variants[variant].disr_val.to_u64_unchecked();
663 let discr_size = discr.size().bytes() as usize;
664 try!(self.memory.write_uint(dest, discr_val, discr_size));
666 let offsets = variants[variant].offset_after_field.iter()
668 try!(self.assign_fields(dest, offsets, operands));
670 panic!("tried to assign {:?} to Layout::General", kind);
674 RawNullablePointer { nndiscr, .. } => {
675 if let mir::AggregateKind::Adt(_, variant, _) = *kind {
676 if nndiscr == variant as u64 {
677 assert_eq!(operands.len(), 1);
678 let operand = &operands[0];
679 let src = try!(self.eval_operand(operand));
680 let src_ty = self.operand_ty(operand);
681 try!(self.move_(src, dest, src_ty));
683 assert_eq!(operands.len(), 0);
684 try!(self.memory.write_isize(dest, 0));
687 panic!("tried to assign {:?} to Layout::RawNullablePointer", kind);
691 CEnum { discr, signed, min, max } => {
692 assert_eq!(operands.len(), 0);
693 if let mir::AggregateKind::Adt(adt_def, variant, _) = *kind {
697 let val = adt_def.variants[variant].disr_val.to_u64().unwrap();
698 let size = discr.size().bytes() as usize;
699 try!(self.memory.write_uint(dest, val, size));
702 panic!("tried to assign {:?} to Layout::CEnum", kind);
706 _ => panic!("can't handle destination layout {:?} when assigning {:?}",
711 Repeat(ref operand, _) => {
712 let (elem_size, length) = match dest_ty.sty {
713 ty::TyArray(elem_ty, n) => (self.type_size(elem_ty), n),
714 _ => panic!("tried to assign array-repeat to non-array type {:?}", dest_ty),
717 let src = try!(self.eval_operand(operand));
719 let elem_dest = dest.offset((i * elem_size) as isize);
720 try!(self.memory.copy(src, elem_dest, elem_size));
725 let src = try!(self.eval_lvalue(lvalue));
726 let ty = self.lvalue_ty(lvalue);
727 let len = match ty.sty {
728 ty::TyArray(_, n) => n as u64,
729 ty::TySlice(_) => if let LvalueExtra::Length(n) = src.extra {
732 panic!("Rvalue::Len of a slice given non-slice pointer: {:?}", src);
734 _ => panic!("Rvalue::Len expected array or slice, got {:?}", ty),
736 try!(self.memory.write_usize(dest, len));
739 Ref(_, _, ref lvalue) => {
740 let lv = try!(self.eval_lvalue(lvalue));
741 try!(self.memory.write_ptr(dest, lv.ptr));
743 LvalueExtra::None => {},
744 LvalueExtra::Length(len) => {
745 let len_ptr = dest.offset(self.memory.pointer_size as isize);
746 try!(self.memory.write_usize(len_ptr, len));
748 LvalueExtra::DowncastVariant(..) =>
749 panic!("attempted to take a reference to an enum downcast lvalue"),
754 let size = self.type_size(ty);
755 let ptr = self.memory.allocate(size);
756 try!(self.memory.write_ptr(dest, ptr));
759 Cast(kind, ref operand, dest_ty) => {
760 let src = try!(self.eval_operand(operand));
761 let src_ty = self.operand_ty(operand);
763 use rustc::mir::repr::CastKind::*;
766 try!(self.move_(src, dest, src_ty));
767 let src_pointee_ty = pointee_type(src_ty).unwrap();
768 let dest_pointee_ty = pointee_type(dest_ty).unwrap();
770 match (&src_pointee_ty.sty, &dest_pointee_ty.sty) {
771 (&ty::TyArray(_, length), &ty::TySlice(_)) => {
772 let len_ptr = dest.offset(self.memory.pointer_size as isize);
773 try!(self.memory.write_usize(len_ptr, length as u64));
776 _ => panic!("can't handle cast: {:?}", rvalue),
781 // FIXME(tsion): Wrong for almost everything.
782 let size = dest_layout.size(&self.tcx.data_layout).bytes() as usize;
783 try!(self.memory.copy(src, dest, size));
786 _ => panic!("can't handle cast: {:?}", rvalue),
790 Slice { .. } => unimplemented!(),
791 InlineAsm { .. } => unimplemented!(),
797 fn eval_operand(&mut self, op: &mir::Operand<'tcx>) -> EvalResult<Pointer> {
798 use rustc::mir::repr::Operand::*;
800 Consume(ref lvalue) =>
801 Ok(try!(self.eval_lvalue(lvalue)).to_ptr()),
802 Constant(mir::Constant { ref literal, .. }) => {
803 use rustc::mir::repr::Literal::*;
805 Value { ref value } => Ok(try!(self.const_to_ptr(value))),
806 Item { .. } => unimplemented!(),
812 fn eval_lvalue(&mut self, lvalue: &mir::Lvalue<'tcx>) -> EvalResult<Lvalue> {
813 use rustc::mir::repr::Lvalue::*;
814 let ptr = match *lvalue {
815 ReturnPointer => self.frame().return_ptr
816 .expect("ReturnPointer used in a function with no return value"),
817 Arg(i) => self.frame().locals[i as usize],
818 Var(i) => self.frame().locals[self.frame().var_offset + i as usize],
819 Temp(i) => self.frame().locals[self.frame().temp_offset + i as usize],
821 Static(_def_id) => unimplemented!(),
823 Projection(ref proj) => {
824 let base = try!(self.eval_lvalue(&proj.base));
825 let base_ty = self.lvalue_ty(&proj.base);
826 let base_layout = self.type_layout(base_ty);
828 use rustc::mir::repr::ProjectionElem::*;
831 let variant = match *base_layout {
832 Layout::Univariant { ref variant, .. } => variant,
833 Layout::General { ref variants, .. } => {
834 if let LvalueExtra::DowncastVariant(variant_idx) = base.extra {
835 &variants[variant_idx]
837 panic!("field access on enum had no variant index");
840 Layout::RawNullablePointer { .. } => {
841 assert_eq!(field.index(), 0);
844 _ => panic!("field access on non-product type: {:?}", base_layout),
847 let offset = variant.field_offset(field.index()).bytes();
848 base.ptr.offset(offset as isize)
851 Downcast(_, variant) => match *base_layout {
852 Layout::General { discr, .. } => {
854 ptr: base.ptr.offset(discr.size().bytes() as isize),
855 extra: LvalueExtra::DowncastVariant(variant),
858 Layout::RawNullablePointer { .. } => return Ok(base),
859 _ => panic!("variant downcast on non-aggregate type: {:?}", base_layout),
863 let pointee_ty = pointee_type(base_ty).expect("Deref of non-pointer");
864 let ptr = try!(self.memory.read_ptr(base.ptr));
865 let extra = match pointee_ty.sty {
866 ty::TySlice(_) | ty::TyStr => {
867 let len_ptr = base.ptr.offset(self.memory.pointer_size as isize);
868 let len = try!(self.memory.read_usize(len_ptr));
869 LvalueExtra::Length(len)
871 ty::TyTrait(_) => unimplemented!(),
872 _ => LvalueExtra::None,
874 return Ok(Lvalue { ptr: ptr, extra: extra });
877 Index(ref operand) => {
878 let elem_size = match base_ty.sty {
879 ty::TyArray(elem_ty, _) |
880 ty::TySlice(elem_ty) => self.type_size(elem_ty),
881 _ => panic!("indexing expected an array or slice, got {:?}", base_ty),
883 let n_ptr = try!(self.eval_operand(operand));
884 let n = try!(self.memory.read_usize(n_ptr));
885 base.ptr.offset(n as isize * elem_size as isize)
888 ConstantIndex { .. } => unimplemented!(),
893 Ok(Lvalue { ptr: ptr, extra: LvalueExtra::None })
896 // TODO(tsion): Try making const_to_primval instead.
897 fn const_to_ptr(&mut self, const_val: &const_val::ConstVal) -> EvalResult<Pointer> {
898 use rustc::middle::const_val::ConstVal::*;
900 Float(_f) => unimplemented!(),
902 // TODO(tsion): Check int constant type.
903 let ptr = self.memory.allocate(8);
904 try!(self.memory.write_uint(ptr, int.to_u64_unchecked(), 8));
908 let psize = self.memory.pointer_size;
909 let static_ptr = self.memory.allocate(s.len());
910 let ptr = self.memory.allocate(psize * 2);
911 try!(self.memory.write_bytes(static_ptr, s.as_bytes()));
912 try!(self.memory.write_ptr(ptr, static_ptr));
913 try!(self.memory.write_usize(ptr.offset(psize as isize), s.len() as u64));
917 let psize = self.memory.pointer_size;
918 let static_ptr = self.memory.allocate(bs.len());
919 let ptr = self.memory.allocate(psize);
920 try!(self.memory.write_bytes(static_ptr, bs));
921 try!(self.memory.write_ptr(ptr, static_ptr));
925 let ptr = self.memory.allocate(1);
926 try!(self.memory.write_bool(ptr, b));
929 Char(_c) => unimplemented!(),
930 Struct(_node_id) => unimplemented!(),
931 Tuple(_node_id) => unimplemented!(),
932 Function(_def_id) => unimplemented!(),
933 Array(_, _) => unimplemented!(),
934 Repeat(_, _) => unimplemented!(),
935 Dummy => unimplemented!(),
939 fn lvalue_ty(&self, lvalue: &mir::Lvalue<'tcx>) -> ty::Ty<'tcx> {
940 self.monomorphize(self.mir().lvalue_ty(self.tcx, lvalue).to_ty(self.tcx))
943 fn operand_ty(&self, operand: &mir::Operand<'tcx>) -> ty::Ty<'tcx> {
944 self.monomorphize(self.mir().operand_ty(self.tcx, operand))
947 fn monomorphize(&self, ty: ty::Ty<'tcx>) -> ty::Ty<'tcx> {
948 let substituted = ty.subst(self.tcx, self.substs());
949 infer::normalize_associated_type(self.tcx, &substituted)
952 fn type_needs_drop(&self, ty: ty::Ty<'tcx>) -> bool {
953 self.tcx.type_needs_drop_given_env(ty, &self.tcx.empty_parameter_environment())
956 fn move_(&mut self, src: Pointer, dest: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<()> {
957 let size = self.type_size(ty);
958 try!(self.memory.copy(src, dest, size));
959 if self.type_needs_drop(ty) {
960 try!(self.memory.drop_fill(src, size));
965 fn type_is_sized(&self, ty: ty::Ty<'tcx>) -> bool {
966 ty.is_sized(&self.tcx.empty_parameter_environment(), DUMMY_SP)
969 fn type_size(&self, ty: ty::Ty<'tcx>) -> usize {
970 self.type_layout(ty).size(&self.tcx.data_layout).bytes() as usize
973 fn type_layout(&self, ty: ty::Ty<'tcx>) -> &'tcx Layout {
974 // TODO(tsion): Is this inefficient? Needs investigation.
975 let ty = self.monomorphize(ty);
977 let infcx = infer::normalizing_infer_ctxt(self.tcx, &self.tcx.tables, ProjectionMode::Any);
979 // TODO(tsion): Report this error properly.
980 ty.layout(&infcx).unwrap()
983 pub fn read_primval(&mut self, ptr: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<PrimVal> {
984 use syntax::ast::{IntTy, UintTy};
985 let val = match ty.sty {
986 ty::TyBool => PrimVal::Bool(try!(self.memory.read_bool(ptr))),
987 ty::TyInt(IntTy::I8) => PrimVal::I8(try!(self.memory.read_int(ptr, 1)) as i8),
988 ty::TyInt(IntTy::I16) => PrimVal::I16(try!(self.memory.read_int(ptr, 2)) as i16),
989 ty::TyInt(IntTy::I32) => PrimVal::I32(try!(self.memory.read_int(ptr, 4)) as i32),
990 ty::TyInt(IntTy::I64) => PrimVal::I64(try!(self.memory.read_int(ptr, 8)) as i64),
991 ty::TyUint(UintTy::U8) => PrimVal::U8(try!(self.memory.read_uint(ptr, 1)) as u8),
992 ty::TyUint(UintTy::U16) => PrimVal::U16(try!(self.memory.read_uint(ptr, 2)) as u16),
993 ty::TyUint(UintTy::U32) => PrimVal::U32(try!(self.memory.read_uint(ptr, 4)) as u32),
994 ty::TyUint(UintTy::U64) => PrimVal::U64(try!(self.memory.read_uint(ptr, 8)) as u64),
996 // TODO(tsion): Pick the PrimVal dynamically.
997 ty::TyInt(IntTy::Is) => PrimVal::I64(try!(self.memory.read_isize(ptr))),
998 ty::TyUint(UintTy::Us) => PrimVal::U64(try!(self.memory.read_usize(ptr))),
1000 ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
1001 ty::TyRawPtr(ty::TypeAndMut { ty, .. }) => {
1002 if self.type_is_sized(ty) {
1003 match self.memory.read_ptr(ptr) {
1004 Ok(p) => PrimVal::AbstractPtr(p),
1005 Err(EvalError::ReadBytesAsPointer) => {
1006 let n = try!(self.memory.read_usize(ptr));
1007 PrimVal::IntegerPtr(n)
1009 Err(e) => return Err(e),
1012 panic!("unimplemented: primitive read of fat pointer type: {:?}", ty);
1016 _ => panic!("primitive read of non-primitive type: {:?}", ty),
1021 fn frame(&self) -> &Frame<'a, 'tcx> {
1022 self.stack.last().expect("no call frames exist")
1025 fn frame_mut(&mut self) -> &mut Frame<'a, 'tcx> {
1026 self.stack.last_mut().expect("no call frames exist")
1029 fn mir(&self) -> &mir::Mir<'tcx> {
1033 fn substs(&self) -> &'tcx Substs<'tcx> {
1034 self.substs_stack.last().cloned().unwrap_or_else(|| self.tcx.mk_substs(Substs::empty()))
1037 fn load_mir(&self, def_id: DefId) -> CachedMir<'a, 'tcx> {
1038 match self.tcx.map.as_local_node_id(def_id) {
1039 Some(node_id) => CachedMir::Ref(self.mir_map.map.get(&node_id).unwrap()),
1041 let mut mir_cache = self.mir_cache.borrow_mut();
1042 if let Some(mir) = mir_cache.get(&def_id) {
1043 return CachedMir::Owned(mir.clone());
1046 use rustc::middle::cstore::CrateStore;
1047 let cs = &self.tcx.sess.cstore;
1048 let mir = cs.maybe_get_item_mir(self.tcx, def_id).unwrap_or_else(|| {
1049 panic!("no mir for {:?}", def_id);
1051 let cached = Rc::new(mir);
1052 mir_cache.insert(def_id, cached.clone());
1053 CachedMir::Owned(cached)
1058 fn fulfill_obligation(&self, trait_ref: ty::PolyTraitRef<'tcx>) -> traits::Vtable<'tcx, ()> {
1059 // Do the initial selection for the obligation. This yields the shallow result we are
1060 // looking for -- that is, what specific impl.
1061 let infcx = infer::normalizing_infer_ctxt(self.tcx, &self.tcx.tables, ProjectionMode::Any);
1062 let mut selcx = traits::SelectionContext::new(&infcx);
1064 let obligation = traits::Obligation::new(
1065 traits::ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID),
1066 trait_ref.to_poly_trait_predicate(),
1068 let selection = selcx.select(&obligation).unwrap().unwrap();
1070 // Currently, we use a fulfillment context to completely resolve all nested obligations.
1071 // This is because they can inform the inference of the impl's type parameters.
1072 let mut fulfill_cx = traits::FulfillmentContext::new();
1073 let vtable = selection.map(|predicate| {
1074 fulfill_cx.register_predicate_obligation(&infcx, predicate);
1076 infer::drain_fulfillment_cx_or_panic(
1077 DUMMY_SP, &infcx, &mut fulfill_cx, &vtable
1081 /// Trait method, which has to be resolved to an impl method.
1082 pub fn trait_method(&self, def_id: DefId, substs: &'tcx Substs<'tcx>)
1083 -> (DefId, &'tcx Substs<'tcx>)
1085 let method_item = self.tcx.impl_or_trait_item(def_id);
1086 let trait_id = method_item.container().id();
1087 let trait_ref = ty::Binder(substs.to_trait_ref(self.tcx, trait_id));
1088 match self.fulfill_obligation(trait_ref) {
1089 traits::VtableImpl(vtable_impl) => {
1090 let impl_did = vtable_impl.impl_def_id;
1091 let mname = self.tcx.item_name(def_id);
1092 // Create a concatenated set of substitutions which includes those from the impl
1093 // and those from the method:
1094 let impl_substs = vtable_impl.substs.with_method_from(substs);
1095 let substs = self.tcx.mk_substs(impl_substs);
1096 let mth = get_impl_method(self.tcx, impl_did, substs, mname);
1098 (mth.method.def_id, mth.substs)
1101 traits::VtableClosure(vtable_closure) =>
1102 (vtable_closure.closure_def_id, vtable_closure.substs.func_substs),
1104 traits::VtableFnPointer(_fn_ty) => {
1105 let _trait_closure_kind = self.tcx.lang_items.fn_trait_kind(trait_id).unwrap();
1107 // let llfn = trans_fn_pointer_shim(ccx, trait_closure_kind, fn_ty);
1109 // let method_ty = def_ty(tcx, def_id, substs);
1110 // let fn_ptr_ty = match method_ty.sty {
1111 // ty::TyFnDef(_, _, fty) => tcx.mk_ty(ty::TyFnPtr(fty)),
1112 // _ => unreachable!("expected fn item type, found {}",
1115 // Callee::ptr(immediate_rvalue(llfn, fn_ptr_ty))
1118 traits::VtableObject(ref _data) => {
1121 // data: Virtual(traits::get_vtable_index_of_object_method(
1122 // tcx, data, def_id)),
1123 // ty: def_ty(tcx, def_id, substs)
1126 vtable => unreachable!("resolved vtable bad vtable {:?} in trans", vtable),
1131 fn pointee_type(ptr_ty: ty::Ty) -> Option<ty::Ty> {
1133 ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
1134 ty::TyRawPtr(ty::TypeAndMut { ty, .. }) |
1143 fn to_ptr(self) -> Pointer {
1144 assert_eq!(self.extra, LvalueExtra::None);
1149 impl<'mir, 'tcx: 'mir> Deref for CachedMir<'mir, 'tcx> {
1150 type Target = mir::Mir<'tcx>;
1151 fn deref(&self) -> &mir::Mir<'tcx> {
1153 CachedMir::Ref(r) => r,
1154 CachedMir::Owned(ref rc) => &rc,
1160 pub struct ImplMethod<'tcx> {
1161 pub method: Rc<ty::Method<'tcx>>,
1162 pub substs: &'tcx Substs<'tcx>,
1163 pub is_provided: bool,
1166 /// Locates the applicable definition of a method, given its name.
1167 pub fn get_impl_method<'tcx>(
1170 substs: &'tcx Substs<'tcx>,
1172 ) -> ImplMethod<'tcx> {
1173 assert!(!substs.types.needs_infer());
1175 let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
1176 let trait_def = tcx.lookup_trait_def(trait_def_id);
1177 let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables, ProjectionMode::Any);
1179 match trait_def.ancestors(impl_def_id).fn_defs(tcx, name).next() {
1180 Some(node_item) => {
1182 method: node_item.item,
1183 substs: traits::translate_substs(&infcx, impl_def_id, substs, node_item.node),
1184 is_provided: node_item.node.is_from_trait(),
1188 bug!("method {:?} not found in {:?}", name, impl_def_id);
1193 pub fn interpret_start_points<'tcx>(tcx: &TyCtxt<'tcx>, mir_map: &MirMap<'tcx>) {
1194 for (&id, mir) in &mir_map.map {
1195 for attr in tcx.map.attrs(id) {
1196 use syntax::attr::AttrMetaMethods;
1197 if attr.check_name("miri_run") {
1198 let item = tcx.map.expect_item(id);
1200 println!("Interpreting: {}", item.name);
1202 let mut miri = Interpreter::new(tcx, mir_map);
1203 let return_ptr = match mir.return_ty {
1204 ty::FnConverging(ty) => {
1205 let size = miri.type_size(ty);
1206 Some(miri.memory.allocate(size))
1208 ty::FnDiverging => None,
1210 let substs = miri.tcx.mk_substs(Substs::empty());
1211 miri.push_stack_frame(CachedMir::Ref(mir), substs, return_ptr);
1212 if let Err(_e) = miri.run() {
1213 // TODO(tsion): Detect whether the error was already reported or not.
1214 // tcx.sess.err(&e.to_string());
1215 } else if let Some(ret) = return_ptr {
1216 miri.memory.dump(ret.alloc_id);
1224 // TODO(tsion): Upstream these methods into rustc::ty::layout.
1227 fn size(self) -> Size;
1230 impl IntegerExt for layout::Integer {
1231 fn size(self) -> Size {
1232 use rustc::ty::layout::Integer::*;
1234 I1 | I8 => Size::from_bits(8),
1235 I16 => Size::from_bits(16),
1236 I32 => Size::from_bits(32),
1237 I64 => Size::from_bits(64),
1243 fn field_offset(&self, index: usize) -> Size;
1246 impl StructExt for layout::Struct {
1247 fn field_offset(&self, index: usize) -> Size {
1251 self.offset_after_field[index - 1]