1 use rustc::middle::const_val;
2 use rustc::hir::def_id::DefId;
3 use rustc::mir::mir_map::MirMap;
4 use rustc::mir::repr as mir;
5 use rustc::traits::{self, ProjectionMode};
6 use rustc::ty::fold::TypeFoldable;
7 use rustc::ty::layout::{self, Layout, Size};
8 use rustc::ty::subst::{self, Subst, Substs};
9 use rustc::ty::{self, Ty, TyCtxt};
10 use rustc::util::nodemap::DefIdMap;
11 use rustc_data_structures::indexed_vec::Idx;
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 use std::collections::HashMap;
28 pub fn step<'ecx, 'a: 'ecx, 'tcx: 'a>(ecx: &'ecx mut EvalContext<'a, 'tcx>) -> EvalResult<bool> {
29 stepper::Stepper::new(ecx).step()
32 pub struct EvalContext<'a, 'tcx: 'a> {
33 /// The results of the type checker, from rustc.
34 tcx: TyCtxt<'a, 'tcx, 'tcx>,
36 /// A mapping from NodeIds to Mir, from rustc. Only contains MIR for crate-local items.
37 mir_map: &'a MirMap<'tcx>,
39 /// A local cache from DefIds to Mir for non-crate-local items.
40 mir_cache: RefCell<DefIdMap<Rc<mir::Mir<'tcx>>>>,
42 /// The virtual memory system.
45 /// Precomputed statics, constants and promoteds
46 statics: HashMap<ConstantId<'tcx>, Pointer>,
48 /// The virtual call stack.
49 stack: Vec<Frame<'a, 'tcx>>,
53 pub struct Frame<'a, 'tcx: 'a> {
54 /// The def_id of the current function
57 /// The span of the call site
58 pub span: codemap::Span,
60 /// type substitutions for the current function invocation
61 pub substs: &'tcx Substs<'tcx>,
63 /// The MIR for the function called on this frame.
64 pub mir: CachedMir<'a, 'tcx>,
66 /// The block that is currently executed (or will be executed after the above call stacks return)
67 pub next_block: mir::BasicBlock,
69 /// A pointer for writing the return value of the current call if it's not a diverging call.
70 pub return_ptr: Option<Pointer>,
72 /// The list of locals for the current function, stored in order as
73 /// `[arguments..., variables..., temporaries...]`. The variables begin at `self.var_offset`
74 /// and the temporaries at `self.temp_offset`.
75 pub locals: Vec<Pointer>,
77 /// The offset of the first variable in `self.locals`.
78 pub var_offset: usize,
80 /// The offset of the first temporary in `self.locals`.
81 pub temp_offset: usize,
83 /// The index of the currently evaluated statment
87 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
93 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
97 // TODO(solson): Vtable(memory::AllocId),
98 DowncastVariant(usize),
102 pub enum CachedMir<'mir, 'tcx: 'mir> {
103 Ref(&'mir mir::Mir<'tcx>),
104 Owned(Rc<mir::Mir<'tcx>>)
107 #[derive(Clone, Debug, Eq, PartialEq, Hash)]
108 /// Uniquely identifies a specific constant or static
109 struct ConstantId<'tcx> {
110 /// the def id of the constant/static or in case of promoteds, the def id of the function they belong to
112 /// In case of statics and constants this is `Substs::empty()`, so only promoteds and associated
113 /// constants actually have something useful here. We could special case statics and constants,
114 /// but that would only require more branching when working with constants, and not bring any
116 substs: &'tcx Substs<'tcx>,
120 #[derive(Clone, Debug, Eq, PartialEq, Hash)]
122 Promoted(mir::Promoted),
123 /// Statics, constants and associated constants
127 impl<'a, 'tcx> EvalContext<'a, 'tcx> {
128 pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, mir_map: &'a MirMap<'tcx>) -> Self {
132 mir_cache: RefCell::new(DefIdMap()),
133 memory: Memory::new(tcx.sess
137 .expect("Session::target::uint_type was usize")/8),
138 statics: HashMap::new(),
143 pub fn alloc_ret_ptr(&mut self, output_ty: ty::FnOutput<'tcx>, substs: &'tcx Substs<'tcx>) -> Option<Pointer> {
145 ty::FnConverging(ty) => {
146 let size = self.type_size(ty, substs);
147 Some(self.memory.allocate(size))
149 ty::FnDiverging => None,
153 pub fn memory(&self) -> &Memory {
157 pub fn stack(&self) -> &[Frame] {
161 // TODO(solson): Try making const_to_primval instead.
162 fn const_to_ptr(&mut self, const_val: &const_val::ConstVal) -> EvalResult<Pointer> {
163 use rustc::middle::const_val::ConstVal::*;
165 Float(_f) => unimplemented!(),
167 // TODO(solson): Check int constant type.
168 let ptr = self.memory.allocate(8);
169 self.memory.write_uint(ptr, int.to_u64_unchecked(), 8)?;
173 let psize = self.memory.pointer_size;
174 let static_ptr = self.memory.allocate(s.len());
175 let ptr = self.memory.allocate(psize * 2);
176 self.memory.write_bytes(static_ptr, s.as_bytes())?;
177 self.memory.write_ptr(ptr, static_ptr)?;
178 self.memory.write_usize(ptr.offset(psize as isize), s.len() as u64)?;
182 let psize = self.memory.pointer_size;
183 let static_ptr = self.memory.allocate(bs.len());
184 let ptr = self.memory.allocate(psize);
185 self.memory.write_bytes(static_ptr, bs)?;
186 self.memory.write_ptr(ptr, static_ptr)?;
190 let ptr = self.memory.allocate(1);
191 self.memory.write_bool(ptr, b)?;
194 Char(_c) => unimplemented!(),
195 Struct(_node_id) => unimplemented!(),
196 Tuple(_node_id) => unimplemented!(),
197 Function(_def_id) => unimplemented!(),
198 Array(_, _) => unimplemented!(),
199 Repeat(_, _) => unimplemented!(),
200 Dummy => unimplemented!(),
204 fn type_needs_drop(&self, ty: Ty<'tcx>) -> bool {
205 self.tcx.type_needs_drop_given_env(ty, &self.tcx.empty_parameter_environment())
208 fn type_is_sized(&self, ty: Ty<'tcx>) -> bool {
209 ty.is_sized(self.tcx, &self.tcx.empty_parameter_environment(), DUMMY_SP)
212 fn fulfill_obligation(&self, trait_ref: ty::PolyTraitRef<'tcx>) -> traits::Vtable<'tcx, ()> {
213 // Do the initial selection for the obligation. This yields the shallow result we are
214 // looking for -- that is, what specific impl.
215 self.tcx.normalizing_infer_ctxt(ProjectionMode::Any).enter(|infcx| {
216 let mut selcx = traits::SelectionContext::new(&infcx);
218 let obligation = traits::Obligation::new(
219 traits::ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID),
220 trait_ref.to_poly_trait_predicate(),
222 let selection = selcx.select(&obligation).unwrap().unwrap();
224 // Currently, we use a fulfillment context to completely resolve all nested obligations.
225 // This is because they can inform the inference of the impl's type parameters.
226 let mut fulfill_cx = traits::FulfillmentContext::new();
227 let vtable = selection.map(|predicate| {
228 fulfill_cx.register_predicate_obligation(&infcx, predicate);
230 infcx.drain_fulfillment_cx_or_panic(DUMMY_SP, &mut fulfill_cx, &vtable)
234 /// Trait method, which has to be resolved to an impl method.
238 substs: &'tcx Substs<'tcx>
239 ) -> (DefId, &'tcx Substs<'tcx>) {
240 let method_item = self.tcx.impl_or_trait_item(def_id);
241 let trait_id = method_item.container().id();
242 let trait_ref = ty::Binder(substs.to_trait_ref(self.tcx, trait_id));
243 match self.fulfill_obligation(trait_ref) {
244 traits::VtableImpl(vtable_impl) => {
245 let impl_did = vtable_impl.impl_def_id;
246 let mname = self.tcx.item_name(def_id);
247 // Create a concatenated set of substitutions which includes those from the impl
248 // and those from the method:
249 let impl_substs = vtable_impl.substs.with_method_from(substs);
250 let substs = self.tcx.mk_substs(impl_substs);
251 let mth = get_impl_method(self.tcx, impl_did, substs, mname);
253 (mth.method.def_id, mth.substs)
256 traits::VtableClosure(vtable_closure) =>
257 (vtable_closure.closure_def_id, vtable_closure.substs.func_substs),
259 traits::VtableFnPointer(_fn_ty) => {
260 let _trait_closure_kind = self.tcx.lang_items.fn_trait_kind(trait_id).unwrap();
262 // let llfn = trans_fn_pointer_shim(ccx, trait_closure_kind, fn_ty);
264 // let method_ty = def_ty(tcx, def_id, substs);
265 // let fn_ptr_ty = match method_ty.sty {
266 // ty::TyFnDef(_, _, fty) => tcx.mk_ty(ty::TyFnPtr(fty)),
267 // _ => unreachable!("expected fn item type, found {}",
270 // Callee::ptr(immediate_rvalue(llfn, fn_ptr_ty))
273 traits::VtableObject(ref _data) => {
276 // data: Virtual(traits::get_vtable_index_of_object_method(
277 // tcx, data, def_id)),
278 // ty: def_ty(tcx, def_id, substs)
281 vtable => unreachable!("resolved vtable bad vtable {:?} in trans", vtable),
285 fn load_mir(&self, def_id: DefId) -> CachedMir<'a, 'tcx> {
286 match self.tcx.map.as_local_node_id(def_id) {
287 Some(node_id) => CachedMir::Ref(self.mir_map.map.get(&node_id).unwrap()),
289 let mut mir_cache = self.mir_cache.borrow_mut();
290 if let Some(mir) = mir_cache.get(&def_id) {
291 return CachedMir::Owned(mir.clone());
294 let cs = &self.tcx.sess.cstore;
295 let mir = cs.maybe_get_item_mir(self.tcx, def_id).unwrap_or_else(|| {
296 panic!("no mir for {:?}", def_id);
298 let cached = Rc::new(mir);
299 mir_cache.insert(def_id, cached.clone());
300 CachedMir::Owned(cached)
305 fn monomorphize(&self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
306 let substituted = ty.subst(self.tcx, substs);
307 self.tcx.normalize_associated_type(&substituted)
310 fn type_size(&self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>) -> usize {
311 self.type_layout(ty, substs).size(&self.tcx.data_layout).bytes() as usize
314 fn type_layout(&self, ty: Ty<'tcx>, substs: &'tcx Substs<'tcx>) -> &'tcx Layout {
315 // TODO(solson): Is this inefficient? Needs investigation.
316 let ty = self.monomorphize(ty, substs);
318 self.tcx.normalizing_infer_ctxt(ProjectionMode::Any).enter(|infcx| {
319 // TODO(solson): Report this error properly.
320 ty.layout(&infcx).unwrap()
324 pub fn push_stack_frame(&mut self, def_id: DefId, span: codemap::Span, mir: CachedMir<'a, 'tcx>, substs: &'tcx Substs<'tcx>,
325 return_ptr: Option<Pointer>)
327 let arg_tys = mir.arg_decls.iter().map(|a| a.ty);
328 let var_tys = mir.var_decls.iter().map(|v| v.ty);
329 let temp_tys = mir.temp_decls.iter().map(|t| t.ty);
331 let num_args = mir.arg_decls.len();
332 let num_vars = mir.var_decls.len();
334 ::log_settings::settings().indentation += 1;
336 let locals: Vec<Pointer> = arg_tys.chain(var_tys).chain(temp_tys).map(|ty| {
337 let size = self.type_size(ty, substs);
338 self.memory.allocate(size)
341 self.stack.push(Frame {
343 next_block: mir::START_BLOCK,
344 return_ptr: return_ptr,
346 var_offset: num_args,
347 temp_offset: num_args + num_vars,
355 fn pop_stack_frame(&mut self) {
356 ::log_settings::settings().indentation -= 1;
357 let _frame = self.stack.pop().expect("tried to pop a stack frame, but there were none");
358 // TODO(solson): Deallocate local variables.
361 fn eval_terminator(&mut self, terminator: &mir::Terminator<'tcx>)
363 use rustc::mir::repr::TerminatorKind::*;
364 match terminator.kind {
365 Return => self.pop_stack_frame(),
368 self.frame_mut().next_block = target;
371 If { ref cond, targets: (then_target, else_target) } => {
372 let cond_ptr = self.eval_operand(cond)?;
373 let cond_val = self.memory.read_bool(cond_ptr)?;
374 self.frame_mut().next_block = if cond_val { then_target } else { else_target };
377 SwitchInt { ref discr, ref values, ref targets, .. } => {
378 let discr_ptr = self.eval_lvalue(discr)?.to_ptr();
379 let discr_size = self
380 .type_layout(self.lvalue_ty(discr), self.substs())
381 .size(&self.tcx.data_layout)
383 let discr_val = self.memory.read_uint(discr_ptr, discr_size)?;
385 // Branch to the `otherwise` case by default, if no match is found.
386 let mut target_block = targets[targets.len() - 1];
388 for (index, val_const) in values.iter().enumerate() {
389 let ptr = self.const_to_ptr(val_const)?;
390 let val = self.memory.read_uint(ptr, discr_size)?;
391 if discr_val == val {
392 target_block = targets[index];
397 self.frame_mut().next_block = target_block;
400 Switch { ref discr, ref targets, adt_def } => {
401 let adt_ptr = self.eval_lvalue(discr)?.to_ptr();
402 let adt_ty = self.lvalue_ty(discr);
403 let discr_val = self.read_discriminant_value(adt_ptr, adt_ty)?;
404 let matching = adt_def.variants.iter()
405 .position(|v| discr_val == v.disr_val.to_u64_unchecked());
409 self.frame_mut().next_block = targets[i];
411 None => return Err(EvalError::InvalidDiscriminant),
415 Call { ref func, ref args, ref destination, .. } => {
416 let mut return_ptr = None;
417 if let Some((ref lv, target)) = *destination {
418 self.frame_mut().next_block = target;
419 return_ptr = Some(self.eval_lvalue(lv)?.to_ptr());
422 let func_ty = self.operand_ty(func);
424 ty::TyFnDef(def_id, substs, fn_ty) => {
425 use syntax::abi::Abi;
427 Abi::RustIntrinsic => {
428 let name = self.tcx.item_name(def_id).as_str();
429 match fn_ty.sig.0.output {
430 ty::FnConverging(ty) => {
431 let size = self.type_size(ty, self.substs());
432 let ret = return_ptr.unwrap();
433 self.call_intrinsic(&name, substs, args, ret, size)?
435 ty::FnDiverging => unimplemented!(),
440 match fn_ty.sig.0.output {
441 ty::FnConverging(ty) => {
442 let size = self.type_size(ty, self.substs());
443 self.call_c_abi(def_id, args, return_ptr.unwrap(), size)?
445 ty::FnDiverging => unimplemented!(),
449 Abi::Rust | Abi::RustCall => {
450 // TODO(solson): Adjust the first argument when calling a Fn or
451 // FnMut closure via FnOnce::call_once.
453 // Only trait methods can have a Self parameter.
454 let (resolved_def_id, resolved_substs) = if substs.self_ty().is_some() {
455 self.trait_method(def_id, substs)
460 let mut arg_srcs = Vec::new();
462 let src = self.eval_operand(arg)?;
463 let src_ty = self.operand_ty(arg);
464 arg_srcs.push((src, src_ty));
467 if fn_ty.abi == Abi::RustCall && !args.is_empty() {
469 let last_arg = args.last().unwrap();
470 let last = self.eval_operand(last_arg)?;
471 let last_ty = self.operand_ty(last_arg);
472 let last_layout = self.type_layout(last_ty, self.substs());
473 match (&last_ty.sty, last_layout) {
474 (&ty::TyTuple(fields),
475 &Layout::Univariant { ref variant, .. }) => {
476 let offsets = iter::once(0)
477 .chain(variant.offset_after_field.iter()
478 .map(|s| s.bytes()));
479 for (offset, ty) in offsets.zip(fields) {
480 let src = last.offset(offset as isize);
481 arg_srcs.push((src, ty));
484 ty => panic!("expected tuple as last argument in function with 'rust-call' ABI, got {:?}", ty),
488 let mir = self.load_mir(resolved_def_id);
489 self.push_stack_frame(
490 def_id, terminator.source_info.span, mir, resolved_substs,
494 for (i, (src, src_ty)) in arg_srcs.into_iter().enumerate() {
495 let dest = self.frame().locals[i];
496 self.move_(src, dest, src_ty)?;
500 abi => return Err(EvalError::Unimplemented(format!("can't handle function with {:?} ABI", abi))),
504 _ => return Err(EvalError::Unimplemented(format!("can't handle callee of type {:?}", func_ty))),
508 Drop { ref location, target, .. } => {
509 let ptr = self.eval_lvalue(location)?.to_ptr();
510 let ty = self.lvalue_ty(location);
512 self.frame_mut().next_block = target;
515 Assert { ref cond, expected, ref msg, target, cleanup } => {
516 let actual_ptr = self.eval_operand(cond)?;
517 let actual = self.memory.read_bool(actual_ptr)?;
518 if actual == expected {
519 self.frame_mut().next_block = target;
521 panic!("unimplemented: jump to {:?} and print {:?}", cleanup, msg);
525 DropAndReplace { .. } => unimplemented!(),
526 Resume => unimplemented!(),
527 Unreachable => unimplemented!(),
533 fn drop(&mut self, ptr: Pointer, ty: Ty<'tcx>) -> EvalResult<()> {
534 if !self.type_needs_drop(ty) {
535 debug!("no need to drop {:?}", ty);
538 trace!("-need to drop {:?}", ty);
540 // TODO(solson): Call user-defined Drop::drop impls.
543 ty::TyBox(contents_ty) => {
544 match self.memory.read_ptr(ptr) {
545 Ok(contents_ptr) => {
546 self.drop(contents_ptr, contents_ty)?;
547 trace!("-deallocating box");
548 self.memory.deallocate(contents_ptr)?;
550 Err(EvalError::ReadBytesAsPointer) => {
551 let size = self.memory.pointer_size;
552 let possible_drop_fill = self.memory.read_bytes(ptr, size)?;
553 if possible_drop_fill.iter().all(|&b| b == mem::POST_DROP_U8) {
556 return Err(EvalError::ReadBytesAsPointer);
559 Err(e) => return Err(e),
563 // TODO(solson): Implement drop for other relevant types (e.g. aggregates).
568 // FIXME(solson): Trait objects (with no static size) probably get filled, too.
569 let size = self.type_size(ty, self.substs());
570 self.memory.drop_fill(ptr, size)?;
575 fn read_discriminant_value(&self, adt_ptr: Pointer, adt_ty: Ty<'tcx>) -> EvalResult<u64> {
576 use rustc::ty::layout::Layout::*;
577 let adt_layout = self.type_layout(adt_ty, self.substs());
579 let discr_val = match *adt_layout {
580 General { discr, .. } | CEnum { discr, .. } => {
581 let discr_size = discr.size().bytes();
582 self.memory.read_uint(adt_ptr, discr_size as usize)?
585 RawNullablePointer { nndiscr, .. } => {
586 self.read_nonnull_discriminant_value(adt_ptr, nndiscr)?
589 StructWrappedNullablePointer { nndiscr, ref discrfield, .. } => {
590 let offset = self.nonnull_offset(adt_ty, nndiscr, discrfield)?;
591 let nonnull = adt_ptr.offset(offset.bytes() as isize);
592 self.read_nonnull_discriminant_value(nonnull, nndiscr)?
595 // The discriminant_value intrinsic returns 0 for non-sum types.
596 Array { .. } | FatPointer { .. } | Scalar { .. } | Univariant { .. } |
603 fn read_nonnull_discriminant_value(&self, ptr: Pointer, nndiscr: u64) -> EvalResult<u64> {
604 let not_null = match self.memory.read_usize(ptr) {
606 Ok(_) | Err(EvalError::ReadPointerAsBytes) => true,
607 Err(e) => return Err(e),
609 assert!(nndiscr == 0 || nndiscr == 1);
610 Ok(if not_null { nndiscr } else { 1 - nndiscr })
616 substs: &'tcx Substs<'tcx>,
617 args: &[mir::Operand<'tcx>],
620 ) -> EvalResult<()> {
621 let args_res: EvalResult<Vec<Pointer>> = args.iter()
622 .map(|arg| self.eval_operand(arg))
624 let args = args_res?;
627 // FIXME(solson): Handle different integer types correctly.
628 "add_with_overflow" => {
629 let ty = *substs.types.get(subst::FnSpace, 0);
630 let size = self.type_size(ty, self.substs());
631 let left = self.memory.read_int(args[0], size)?;
632 let right = self.memory.read_int(args[1], size)?;
633 let (n, overflowed) = unsafe {
634 ::std::intrinsics::add_with_overflow::<i64>(left, right)
636 self.memory.write_int(dest, n, size)?;
637 self.memory.write_bool(dest.offset(size as isize), overflowed)?;
642 "copy_nonoverlapping" => {
643 let elem_ty = *substs.types.get(subst::FnSpace, 0);
644 let elem_size = self.type_size(elem_ty, self.substs());
645 let src = self.memory.read_ptr(args[0])?;
646 let dest = self.memory.read_ptr(args[1])?;
647 let count = self.memory.read_isize(args[2])?;
648 self.memory.copy(src, dest, count as usize * elem_size)?;
651 "discriminant_value" => {
652 let ty = *substs.types.get(subst::FnSpace, 0);
653 let adt_ptr = self.memory.read_ptr(args[0])?;
654 let discr_val = self.read_discriminant_value(adt_ptr, ty)?;
655 self.memory.write_uint(dest, discr_val, dest_size)?;
659 let arg_ty = *substs.types.get(subst::FnSpace, 0);
660 let arg_size = self.type_size(arg_ty, self.substs());
661 self.memory.drop_fill(args[0], arg_size)?;
664 "init" => self.memory.write_repeat(dest, 0, dest_size)?,
667 self.memory.write_int(dest, 1, dest_size)?;
671 let ty = *substs.types.get(subst::FnSpace, 0);
672 let ptr = self.memory.read_ptr(args[0])?;
673 self.move_(args[1], ptr, ty)?;
676 // FIXME(solson): Handle different integer types correctly.
677 "mul_with_overflow" => {
678 let ty = *substs.types.get(subst::FnSpace, 0);
679 let size = self.type_size(ty, self.substs());
680 let left = self.memory.read_int(args[0], size)?;
681 let right = self.memory.read_int(args[1], size)?;
682 let (n, overflowed) = unsafe {
683 ::std::intrinsics::mul_with_overflow::<i64>(left, right)
685 self.memory.write_int(dest, n, size)?;
686 self.memory.write_bool(dest.offset(size as isize), overflowed)?;
690 let pointee_ty = *substs.types.get(subst::FnSpace, 0);
691 let pointee_size = self.type_size(pointee_ty, self.substs()) as isize;
692 let ptr_arg = args[0];
693 let offset = self.memory.read_isize(args[1])?;
695 match self.memory.read_ptr(ptr_arg) {
697 let result_ptr = ptr.offset(offset as isize * pointee_size);
698 self.memory.write_ptr(dest, result_ptr)?;
700 Err(EvalError::ReadBytesAsPointer) => {
701 let addr = self.memory.read_isize(ptr_arg)?;
702 let result_addr = addr + offset * pointee_size as i64;
703 self.memory.write_isize(dest, result_addr)?;
705 Err(e) => return Err(e),
709 // FIXME(solson): Handle different integer types correctly. Use primvals?
710 "overflowing_sub" => {
711 let ty = *substs.types.get(subst::FnSpace, 0);
712 let size = self.type_size(ty, self.substs());
713 let left = self.memory.read_int(args[0], size)?;
714 let right = self.memory.read_int(args[1], size)?;
715 let n = left.wrapping_sub(right);
716 self.memory.write_int(dest, n, size)?;
720 let ty = *substs.types.get(subst::FnSpace, 0);
721 let size = self.type_size(ty, self.substs()) as u64;
722 self.memory.write_uint(dest, size, dest_size)?;
726 let ty = *substs.types.get(subst::FnSpace, 0);
727 if self.type_is_sized(ty) {
728 let size = self.type_size(ty, self.substs()) as u64;
729 self.memory.write_uint(dest, size, dest_size)?;
732 ty::TySlice(_) | ty::TyStr => {
733 let elem_ty = ty.sequence_element_type(self.tcx);
734 let elem_size = self.type_size(elem_ty, self.substs()) as u64;
735 let ptr_size = self.memory.pointer_size as isize;
736 let n = self.memory.read_usize(args[0].offset(ptr_size))?;
737 self.memory.write_uint(dest, n * elem_size, dest_size)?;
740 _ => return Err(EvalError::Unimplemented(format!("unimplemented: size_of_val::<{:?}>", ty))),
746 let ty = *substs.types.get(subst::FnSpace, 0);
747 self.move_(args[0], dest, ty)?;
749 "uninit" => self.memory.mark_definedness(dest, dest_size, false)?,
751 name => return Err(EvalError::Unimplemented(format!("unimplemented intrinsic: {}", name))),
754 // Since we pushed no stack frame, the main loop will act
755 // as if the call just completed and it's returning to the
763 args: &[mir::Operand<'tcx>],
766 ) -> EvalResult<()> {
767 let name = self.tcx.item_name(def_id);
768 let attrs = self.tcx.get_attrs(def_id);
769 let link_name = match attr::first_attr_value_str_by_name(&attrs, "link_name") {
770 Some(ln) => ln.clone(),
771 None => name.as_str(),
774 let args_res: EvalResult<Vec<Pointer>> = args.iter()
775 .map(|arg| self.eval_operand(arg))
777 let args = args_res?;
779 match &link_name[..] {
780 "__rust_allocate" => {
781 let size = self.memory.read_usize(args[0])?;
782 let ptr = self.memory.allocate(size as usize);
783 self.memory.write_ptr(dest, ptr)?;
786 "__rust_reallocate" => {
787 let ptr = self.memory.read_ptr(args[0])?;
788 let size = self.memory.read_usize(args[2])?;
789 self.memory.reallocate(ptr, size as usize)?;
790 self.memory.write_ptr(dest, ptr)?;
794 let left = self.memory.read_ptr(args[0])?;
795 let right = self.memory.read_ptr(args[1])?;
796 let n = self.memory.read_usize(args[2])? as usize;
799 let left_bytes = self.memory.read_bytes(left, n)?;
800 let right_bytes = self.memory.read_bytes(right, n)?;
802 use std::cmp::Ordering::*;
803 match left_bytes.cmp(right_bytes) {
810 self.memory.write_int(dest, result, dest_size)?;
813 _ => return Err(EvalError::Unimplemented(format!("can't call C ABI function: {}", link_name))),
816 // Since we pushed no stack frame, the main loop will act
817 // as if the call just completed and it's returning to the
822 fn assign_fields<I: IntoIterator<Item = u64>>(
826 operands: &[mir::Operand<'tcx>],
827 ) -> EvalResult<()> {
828 for (offset, operand) in offsets.into_iter().zip(operands) {
829 let src = self.eval_operand(operand)?;
830 let src_ty = self.operand_ty(operand);
831 let field_dest = dest.offset(offset as isize);
832 self.move_(src, field_dest, src_ty)?;
837 fn eval_assignment(&mut self, lvalue: &mir::Lvalue<'tcx>, rvalue: &mir::Rvalue<'tcx>)
840 let dest = self.eval_lvalue(lvalue)?.to_ptr();
841 let dest_ty = self.lvalue_ty(lvalue);
842 let dest_layout = self.type_layout(dest_ty, self.substs());
844 use rustc::mir::repr::Rvalue::*;
846 Use(ref operand) => {
847 let src = self.eval_operand(operand)?;
848 self.move_(src, dest, dest_ty)?;
851 BinaryOp(bin_op, ref left, ref right) => {
852 let left_ptr = self.eval_operand(left)?;
853 let left_ty = self.operand_ty(left);
854 let left_val = self.read_primval(left_ptr, left_ty)?;
856 let right_ptr = self.eval_operand(right)?;
857 let right_ty = self.operand_ty(right);
858 let right_val = self.read_primval(right_ptr, right_ty)?;
860 let val = primval::binary_op(bin_op, left_val, right_val)?;
861 self.memory.write_primval(dest, val)?;
864 CheckedBinaryOp(..) => unimplemented!(),
866 UnaryOp(un_op, ref operand) => {
867 let ptr = self.eval_operand(operand)?;
868 let ty = self.operand_ty(operand);
869 let val = self.read_primval(ptr, ty)?;
870 self.memory.write_primval(dest, primval::unary_op(un_op, val)?)?;
873 Aggregate(ref kind, ref operands) => {
874 use rustc::ty::layout::Layout::*;
876 Univariant { ref variant, .. } => {
877 let offsets = iter::once(0)
878 .chain(variant.offset_after_field.iter().map(|s| s.bytes()));
879 self.assign_fields(dest, offsets, operands)?;
883 let elem_size = match dest_ty.sty {
884 ty::TyArray(elem_ty, _) => self.type_size(elem_ty, self.substs()) as u64,
885 _ => panic!("tried to assign {:?} to non-array type {:?}",
888 let offsets = (0..).map(|i| i * elem_size);
889 self.assign_fields(dest, offsets, operands)?;
892 General { discr, ref variants, .. } => {
893 if let mir::AggregateKind::Adt(adt_def, variant, _) = *kind {
894 let discr_val = adt_def.variants[variant].disr_val.to_u64_unchecked();
895 let discr_size = discr.size().bytes() as usize;
896 self.memory.write_uint(dest, discr_val, discr_size)?;
898 let offsets = variants[variant].offset_after_field.iter()
900 self.assign_fields(dest, offsets, operands)?;
902 panic!("tried to assign {:?} to Layout::General", kind);
906 RawNullablePointer { nndiscr, .. } => {
907 if let mir::AggregateKind::Adt(_, variant, _) = *kind {
908 if nndiscr == variant as u64 {
909 assert_eq!(operands.len(), 1);
910 let operand = &operands[0];
911 let src = self.eval_operand(operand)?;
912 let src_ty = self.operand_ty(operand);
913 self.move_(src, dest, src_ty)?;
915 assert_eq!(operands.len(), 0);
916 self.memory.write_isize(dest, 0)?;
919 panic!("tried to assign {:?} to Layout::RawNullablePointer", kind);
923 StructWrappedNullablePointer { nndiscr, ref nonnull, ref discrfield } => {
924 if let mir::AggregateKind::Adt(_, variant, _) = *kind {
925 if nndiscr == variant as u64 {
926 let offsets = iter::once(0)
927 .chain(nonnull.offset_after_field.iter().map(|s| s.bytes()));
928 try!(self.assign_fields(dest, offsets, operands));
930 assert_eq!(operands.len(), 0);
931 let offset = self.nonnull_offset(dest_ty, nndiscr, discrfield)?;
932 let dest = dest.offset(offset.bytes() as isize);
933 try!(self.memory.write_isize(dest, 0));
936 panic!("tried to assign {:?} to Layout::RawNullablePointer", kind);
940 CEnum { discr, signed, .. } => {
941 assert_eq!(operands.len(), 0);
942 if let mir::AggregateKind::Adt(adt_def, variant, _) = *kind {
943 let val = adt_def.variants[variant].disr_val.to_u64_unchecked();
944 let size = discr.size().bytes() as usize;
947 self.memory.write_int(dest, val as i64, size)?;
949 self.memory.write_uint(dest, val, size)?;
952 panic!("tried to assign {:?} to Layout::CEnum", kind);
956 _ => return Err(EvalError::Unimplemented(format!("can't handle destination layout {:?} when assigning {:?}", dest_layout, kind))),
960 Repeat(ref operand, _) => {
961 let (elem_size, length) = match dest_ty.sty {
962 ty::TyArray(elem_ty, n) => (self.type_size(elem_ty, self.substs()), n),
963 _ => panic!("tried to assign array-repeat to non-array type {:?}", dest_ty),
966 let src = self.eval_operand(operand)?;
968 let elem_dest = dest.offset((i * elem_size) as isize);
969 self.memory.copy(src, elem_dest, elem_size)?;
974 let src = self.eval_lvalue(lvalue)?;
975 let ty = self.lvalue_ty(lvalue);
976 let len = match ty.sty {
977 ty::TyArray(_, n) => n as u64,
978 ty::TySlice(_) => if let LvalueExtra::Length(n) = src.extra {
981 panic!("Rvalue::Len of a slice given non-slice pointer: {:?}", src);
983 _ => panic!("Rvalue::Len expected array or slice, got {:?}", ty),
985 self.memory.write_usize(dest, len)?;
988 Ref(_, _, ref lvalue) => {
989 let lv = self.eval_lvalue(lvalue)?;
990 self.memory.write_ptr(dest, lv.ptr)?;
992 LvalueExtra::None => {},
993 LvalueExtra::Length(len) => {
994 let len_ptr = dest.offset(self.memory.pointer_size as isize);
995 self.memory.write_usize(len_ptr, len)?;
997 LvalueExtra::DowncastVariant(..) =>
998 panic!("attempted to take a reference to an enum downcast lvalue"),
1003 let size = self.type_size(ty, self.substs());
1004 let ptr = self.memory.allocate(size);
1005 self.memory.write_ptr(dest, ptr)?;
1008 Cast(kind, ref operand, dest_ty) => {
1009 let src = self.eval_operand(operand)?;
1010 let src_ty = self.operand_ty(operand);
1012 use rustc::mir::repr::CastKind::*;
1015 self.move_(src, dest, src_ty)?;
1016 let src_pointee_ty = pointee_type(src_ty).unwrap();
1017 let dest_pointee_ty = pointee_type(dest_ty).unwrap();
1019 match (&src_pointee_ty.sty, &dest_pointee_ty.sty) {
1020 (&ty::TyArray(_, length), &ty::TySlice(_)) => {
1021 let len_ptr = dest.offset(self.memory.pointer_size as isize);
1022 self.memory.write_usize(len_ptr, length as u64)?;
1025 _ => return Err(EvalError::Unimplemented(format!("can't handle cast: {:?}", rvalue))),
1030 // FIXME(solson): Wrong for almost everything.
1031 let size = dest_layout.size(&self.tcx.data_layout).bytes() as usize;
1032 self.memory.copy(src, dest, size)?;
1035 _ => return Err(EvalError::Unimplemented(format!("can't handle cast: {:?}", rvalue))),
1039 InlineAsm { .. } => unimplemented!(),
1045 fn nonnull_offset(&self, ty: Ty<'tcx>, nndiscr: u64, discrfield: &[u32]) -> EvalResult<Size> {
1046 // Skip the constant 0 at the start meant for LLVM GEP.
1047 let mut path = discrfield.iter().skip(1).map(|&i| i as usize);
1049 // Handle the field index for the outer non-null variant.
1050 let inner_ty = match ty.sty {
1051 ty::TyEnum(adt_def, substs) => {
1052 let variant = &adt_def.variants[nndiscr as usize];
1053 let index = path.next().unwrap();
1054 let field = &variant.fields[index];
1055 field.ty(self.tcx, substs)
1058 "non-enum for StructWrappedNullablePointer: {}",
1063 self.field_path_offset(inner_ty, path)
1066 fn field_path_offset<I: Iterator<Item = usize>>(&self, mut ty: Ty<'tcx>, path: I) -> EvalResult<Size> {
1067 let mut offset = Size::from_bytes(0);
1069 // Skip the initial 0 intended for LLVM GEP.
1070 for field_index in path {
1071 let field_offset = self.get_field_offset(ty, field_index)?;
1072 ty = self.get_field_ty(ty, field_index)?;
1073 offset = offset.checked_add(field_offset, &self.tcx.data_layout).unwrap();
1079 fn get_field_ty(&self, ty: Ty<'tcx>, field_index: usize) -> EvalResult<Ty<'tcx>> {
1081 ty::TyStruct(adt_def, substs) => {
1082 Ok(adt_def.struct_variant().fields[field_index].ty(self.tcx, substs))
1085 ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
1086 ty::TyRawPtr(ty::TypeAndMut { ty, .. }) |
1088 assert_eq!(field_index, 0);
1091 _ => Err(EvalError::Unimplemented(format!("can't handle type: {:?}", ty))),
1095 fn get_field_offset(&self, ty: Ty<'tcx>, field_index: usize) -> EvalResult<Size> {
1096 let layout = self.type_layout(ty, self.substs());
1098 use rustc::ty::layout::Layout::*;
1100 Univariant { .. } => {
1101 assert_eq!(field_index, 0);
1102 Ok(Size::from_bytes(0))
1104 FatPointer { .. } => {
1105 let bytes = layout::FAT_PTR_ADDR * self.memory.pointer_size;
1106 Ok(Size::from_bytes(bytes as u64))
1108 _ => Err(EvalError::Unimplemented(format!("can't handle type: {:?}, with layout: {:?}", ty, layout))),
1112 fn eval_operand(&mut self, op: &mir::Operand<'tcx>) -> EvalResult<Pointer> {
1113 use rustc::mir::repr::Operand::*;
1115 Consume(ref lvalue) => Ok(self.eval_lvalue(lvalue)?.to_ptr()),
1116 Constant(mir::Constant { ref literal, ty, .. }) => {
1117 use rustc::mir::repr::Literal::*;
1119 Value { ref value } => Ok(self.const_to_ptr(value)?),
1120 Item { def_id, substs } => {
1121 if let ty::TyFnDef(..) = ty.sty {
1122 Err(EvalError::Unimplemented("unimplemented: mentions of function items".to_string()))
1124 let cid = ConstantId {
1127 kind: ConstantKind::Global,
1129 Ok(*self.statics.get(&cid).expect("static should have been cached (rvalue)"))
1132 Promoted { index } => {
1133 let cid = ConstantId {
1134 def_id: self.frame().def_id,
1135 substs: self.substs(),
1136 kind: ConstantKind::Promoted(index),
1138 Ok(*self.statics.get(&cid).expect("a promoted constant hasn't been precomputed"))
1145 fn eval_lvalue(&mut self, lvalue: &mir::Lvalue<'tcx>) -> EvalResult<Lvalue> {
1146 use rustc::mir::repr::Lvalue::*;
1147 let ptr = match *lvalue {
1148 ReturnPointer => self.frame().return_ptr
1149 .expect("ReturnPointer used in a function with no return value"),
1150 Arg(i) => self.frame().locals[i.index()],
1151 Var(i) => self.frame().locals[self.frame().var_offset + i.index()],
1152 Temp(i) => self.frame().locals[self.frame().temp_offset + i.index()],
1155 let substs = self.tcx.mk_substs(subst::Substs::empty());
1156 let cid = ConstantId {
1159 kind: ConstantKind::Global,
1161 *self.statics.get(&cid).expect("static should have been cached (lvalue)")
1164 Projection(ref proj) => {
1165 let base = self.eval_lvalue(&proj.base)?;
1166 let base_ty = self.lvalue_ty(&proj.base);
1167 let base_layout = self.type_layout(base_ty, self.substs());
1169 use rustc::mir::repr::ProjectionElem::*;
1171 Field(field, _) => {
1172 use rustc::ty::layout::Layout::*;
1173 let variant = match *base_layout {
1174 Univariant { ref variant, .. } => variant,
1175 General { ref variants, .. } => {
1176 if let LvalueExtra::DowncastVariant(variant_idx) = base.extra {
1177 &variants[variant_idx]
1179 panic!("field access on enum had no variant index");
1182 RawNullablePointer { .. } => {
1183 assert_eq!(field.index(), 0);
1186 StructWrappedNullablePointer { ref nonnull, .. } => nonnull,
1187 _ => panic!("field access on non-product type: {:?}", base_layout),
1190 let offset = variant.field_offset(field.index()).bytes();
1191 base.ptr.offset(offset as isize)
1194 Downcast(_, variant) => {
1195 use rustc::ty::layout::Layout::*;
1196 match *base_layout {
1197 General { discr, .. } => {
1199 ptr: base.ptr.offset(discr.size().bytes() as isize),
1200 extra: LvalueExtra::DowncastVariant(variant),
1203 RawNullablePointer { .. } | StructWrappedNullablePointer { .. } => {
1206 _ => panic!("variant downcast on non-aggregate: {:?}", base_layout),
1211 let pointee_ty = pointee_type(base_ty).expect("Deref of non-pointer");
1212 let ptr = self.memory.read_ptr(base.ptr)?;
1213 let extra = match pointee_ty.sty {
1214 ty::TySlice(_) | ty::TyStr => {
1215 let len_ptr = base.ptr.offset(self.memory.pointer_size as isize);
1216 let len = self.memory.read_usize(len_ptr)?;
1217 LvalueExtra::Length(len)
1219 ty::TyTrait(_) => unimplemented!(),
1220 _ => LvalueExtra::None,
1222 return Ok(Lvalue { ptr: ptr, extra: extra });
1225 Index(ref operand) => {
1226 let elem_size = match base_ty.sty {
1227 ty::TyArray(elem_ty, _) |
1228 ty::TySlice(elem_ty) => self.type_size(elem_ty, self.substs()),
1229 _ => panic!("indexing expected an array or slice, got {:?}", base_ty),
1231 let n_ptr = self.eval_operand(operand)?;
1232 let n = self.memory.read_usize(n_ptr)?;
1233 base.ptr.offset(n as isize * elem_size as isize)
1236 ConstantIndex { .. } => unimplemented!(),
1237 Subslice { .. } => unimplemented!(),
1242 Ok(Lvalue { ptr: ptr, extra: LvalueExtra::None })
1245 fn lvalue_ty(&self, lvalue: &mir::Lvalue<'tcx>) -> Ty<'tcx> {
1246 self.monomorphize(self.mir().lvalue_ty(self.tcx, lvalue).to_ty(self.tcx), self.substs())
1249 fn operand_ty(&self, operand: &mir::Operand<'tcx>) -> Ty<'tcx> {
1250 self.monomorphize(self.mir().operand_ty(self.tcx, operand), self.substs())
1253 fn move_(&mut self, src: Pointer, dest: Pointer, ty: Ty<'tcx>) -> EvalResult<()> {
1254 let size = self.type_size(ty, self.substs());
1255 self.memory.copy(src, dest, size)?;
1256 if self.type_needs_drop(ty) {
1257 self.memory.drop_fill(src, size)?;
1262 pub fn read_primval(&mut self, ptr: Pointer, ty: Ty<'tcx>) -> EvalResult<PrimVal> {
1263 use syntax::ast::{IntTy, UintTy};
1264 let val = match (self.memory.pointer_size, &ty.sty) {
1265 (_, &ty::TyBool) => PrimVal::Bool(self.memory.read_bool(ptr)?),
1266 (_, &ty::TyInt(IntTy::I8)) => PrimVal::I8(self.memory.read_int(ptr, 1)? as i8),
1267 (2, &ty::TyInt(IntTy::Is)) |
1268 (_, &ty::TyInt(IntTy::I16)) => PrimVal::I16(self.memory.read_int(ptr, 2)? as i16),
1269 (4, &ty::TyInt(IntTy::Is)) |
1270 (_, &ty::TyInt(IntTy::I32)) => PrimVal::I32(self.memory.read_int(ptr, 4)? as i32),
1271 (8, &ty::TyInt(IntTy::Is)) |
1272 (_, &ty::TyInt(IntTy::I64)) => PrimVal::I64(self.memory.read_int(ptr, 8)? as i64),
1273 (_, &ty::TyUint(UintTy::U8)) => PrimVal::U8(self.memory.read_uint(ptr, 1)? as u8),
1274 (2, &ty::TyUint(UintTy::Us)) |
1275 (_, &ty::TyUint(UintTy::U16)) => PrimVal::U16(self.memory.read_uint(ptr, 2)? as u16),
1276 (4, &ty::TyUint(UintTy::Us)) |
1277 (_, &ty::TyUint(UintTy::U32)) => PrimVal::U32(self.memory.read_uint(ptr, 4)? as u32),
1278 (8, &ty::TyUint(UintTy::Us)) |
1279 (_, &ty::TyUint(UintTy::U64)) => PrimVal::U64(self.memory.read_uint(ptr, 8)? as u64),
1281 (_, &ty::TyRef(_, ty::TypeAndMut { ty, .. })) |
1282 (_, &ty::TyRawPtr(ty::TypeAndMut { ty, .. })) => {
1283 if self.type_is_sized(ty) {
1284 match self.memory.read_ptr(ptr) {
1285 Ok(p) => PrimVal::AbstractPtr(p),
1286 Err(EvalError::ReadBytesAsPointer) => {
1287 PrimVal::IntegerPtr(self.memory.read_usize(ptr)?)
1289 Err(e) => return Err(e),
1292 return Err(EvalError::Unimplemented(format!("unimplemented: primitive read of fat pointer type: {:?}", ty)));
1296 _ => panic!("primitive read of non-primitive type: {:?}", ty),
1301 fn frame(&self) -> &Frame<'a, 'tcx> {
1302 self.stack.last().expect("no call frames exist")
1305 fn frame_mut(&mut self) -> &mut Frame<'a, 'tcx> {
1306 self.stack.last_mut().expect("no call frames exist")
1309 fn mir(&self) -> CachedMir<'a, 'tcx> {
1310 self.frame().mir.clone()
1313 fn substs(&self) -> &'tcx Substs<'tcx> {
1318 fn pointee_type(ptr_ty: ty::Ty) -> Option<ty::Ty> {
1320 ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
1321 ty::TyRawPtr(ty::TypeAndMut { ty, .. }) |
1330 fn to_ptr(self) -> Pointer {
1331 assert_eq!(self.extra, LvalueExtra::None);
1336 impl<'mir, 'tcx: 'mir> Deref for CachedMir<'mir, 'tcx> {
1337 type Target = mir::Mir<'tcx>;
1338 fn deref(&self) -> &mir::Mir<'tcx> {
1340 CachedMir::Ref(r) => r,
1341 CachedMir::Owned(ref rc) => rc,
1347 pub struct ImplMethod<'tcx> {
1348 pub method: Rc<ty::Method<'tcx>>,
1349 pub substs: &'tcx Substs<'tcx>,
1350 pub is_provided: bool,
1353 /// Locates the applicable definition of a method, given its name.
1354 pub fn get_impl_method<'a, 'tcx>(
1355 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1357 substs: &'tcx Substs<'tcx>,
1359 ) -> ImplMethod<'tcx> {
1360 assert!(!substs.types.needs_infer());
1362 let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
1363 let trait_def = tcx.lookup_trait_def(trait_def_id);
1365 match trait_def.ancestors(impl_def_id).fn_defs(tcx, name).next() {
1366 Some(node_item) => {
1367 let substs = tcx.normalizing_infer_ctxt(ProjectionMode::Any).enter(|infcx| {
1368 let substs = traits::translate_substs(&infcx, impl_def_id,
1369 substs, node_item.node);
1370 tcx.lift(&substs).unwrap_or_else(|| {
1371 bug!("trans::meth::get_impl_method: translate_substs \
1372 returned {:?} which contains inference types/regions",
1377 method: node_item.item,
1379 is_provided: node_item.node.is_from_trait(),
1383 bug!("method {:?} not found in {:?}", name, impl_def_id)
1388 // TODO(solson): Upstream these methods into rustc::ty::layout.
1391 fn size(self) -> Size;
1394 impl IntegerExt for layout::Integer {
1395 fn size(self) -> Size {
1396 use rustc::ty::layout::Integer::*;
1398 I1 | I8 => Size::from_bits(8),
1399 I16 => Size::from_bits(16),
1400 I32 => Size::from_bits(32),
1401 I64 => Size::from_bits(64),
1407 fn field_offset(&self, index: usize) -> Size;
1410 impl StructExt for layout::Struct {
1411 fn field_offset(&self, index: usize) -> Size {
1415 self.offset_after_field[index - 1]