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;
13 use std::ops::{Deref, DerefMut};
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 = true;
26 struct GlobalEvalContext<'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 /// Another stack containing the type substitutions for the current function invocation. It
40 /// exists separately from `stack` because it must contain the `Substs` for a function while
41 /// *creating* the `Frame` for that same function.
42 substs_stack: Vec<&'tcx Substs<'tcx>>,
44 // TODO(solson): Merge with `substs_stack`. Also try restructuring `Frame` to accomodate.
45 /// A stack of the things necessary to print good strack traces:
46 /// * Function DefIds and Substs to print proper substituted function names.
47 /// * Spans pointing to specific function calls in the source.
48 name_stack: Vec<(DefId, &'tcx Substs<'tcx>, codemap::Span)>,
51 struct FnEvalContext<'a, 'b: 'a + 'mir, 'mir, 'tcx: 'b> {
52 gecx: &'a mut GlobalEvalContext<'b, 'tcx>,
54 /// The virtual call stack.
55 stack: Vec<Frame<'mir, 'tcx>>,
58 impl<'a, 'b, 'mir, 'tcx> Deref for FnEvalContext<'a, 'b, 'mir, 'tcx> {
59 type Target = GlobalEvalContext<'b, 'tcx>;
60 fn deref(&self) -> &Self::Target {
65 impl<'a, 'b, 'mir, 'tcx> DerefMut for FnEvalContext<'a, 'b, 'mir, 'tcx> {
66 fn deref_mut(&mut self) -> &mut Self::Target {
72 struct Frame<'a, 'tcx: 'a> {
73 /// The MIR for the function called on this frame.
74 mir: CachedMir<'a, 'tcx>,
76 /// The block this frame will execute when a function call returns back to this frame.
77 next_block: mir::BasicBlock,
79 /// A pointer for writing the return value of the current call if it's not a diverging call.
80 return_ptr: Option<Pointer>,
82 /// The list of locals for the current function, stored in order as
83 /// `[arguments..., variables..., temporaries...]`. The variables begin at `self.var_offset`
84 /// and the temporaries at `self.temp_offset`.
87 /// The offset of the first variable in `self.locals`.
90 /// The offset of the first temporary in `self.locals`.
94 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
100 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
104 // TODO(solson): Vtable(memory::AllocId),
105 DowncastVariant(usize),
109 enum CachedMir<'mir, 'tcx: 'mir> {
110 Ref(&'mir mir::Mir<'tcx>),
111 Owned(Rc<mir::Mir<'tcx>>)
114 /// Represents the action to be taken in the main loop as a result of executing a terminator.
115 enum TerminatorTarget {
116 /// Make a local jump to the given block.
117 Block(mir::BasicBlock),
119 /// Start executing from the new current frame. (For function calls.)
122 /// Stop executing the current frame and resume the previous frame.
126 impl<'a, 'tcx> GlobalEvalContext<'a, 'tcx> {
127 fn new(tcx: &'a TyCtxt<'tcx>, mir_map: &'a MirMap<'tcx>) -> Self {
131 mir_cache: RefCell::new(DefIdMap()),
132 memory: Memory::new(),
133 substs_stack: Vec::new(),
134 name_stack: Vec::new(),
139 impl<'a, 'b, 'mir, 'tcx> FnEvalContext<'a, 'b, 'mir, 'tcx> {
140 fn new(gecx: &'a mut GlobalEvalContext<'b, 'tcx>) -> Self {
147 fn maybe_report<T>(&self, span: codemap::Span, r: EvalResult<T>) -> EvalResult<T> {
148 if let Err(ref e) = r {
149 let mut err = self.tcx.sess.struct_span_err(span, &e.to_string());
150 for &(def_id, substs, span) in self.name_stack.iter().rev() {
151 // FIXME(solson): Find a way to do this without this Display impl hack.
152 use rustc::util::ppaux;
154 struct Instance<'tcx>(DefId, &'tcx Substs<'tcx>);
155 impl<'tcx> fmt::Display for Instance<'tcx> {
156 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
157 ppaux::parameterized(f, self.1, self.0, ppaux::Ns::Value, &[],
158 |tcx| tcx.lookup_item_type(self.0).generics)
161 err.span_note(span, &format!("inside call to {}", Instance(def_id, substs)));
168 fn log<F>(&self, extra_indent: usize, f: F) where F: FnOnce() {
169 let indent = self.stack.len() + extra_indent;
170 if !TRACE_EXECUTION { return; }
171 for _ in 0..indent { print!(" "); }
176 fn run(&mut self) -> EvalResult<()> {
177 'outer: while !self.stack.is_empty() {
178 let mut current_block = self.frame().next_block;
181 self.log(0, || print!("// {:?}", current_block));
182 let current_mir = self.mir().clone(); // Cloning a reference.
183 let block_data = current_mir.basic_block_data(current_block);
185 for stmt in &block_data.statements {
186 self.log(0, || print!("{:?}", stmt));
187 let mir::StatementKind::Assign(ref lvalue, ref rvalue) = stmt.kind;
188 let result = self.eval_assignment(lvalue, rvalue);
189 self.maybe_report(stmt.span, result)?;
192 let terminator = block_data.terminator();
193 self.log(0, || print!("{:?}", terminator.kind));
195 let result = self.eval_terminator(terminator);
196 match self.maybe_report(terminator.span, result)? {
197 TerminatorTarget::Block(block) => current_block = block,
198 TerminatorTarget::Return => {
199 self.pop_stack_frame();
200 self.name_stack.pop();
203 TerminatorTarget::Call => continue 'outer,
211 fn call_nested(&mut self, mir: &mir::Mir<'tcx>) -> EvalResult<Option<Pointer>> {
212 let mut nested_fecx = FnEvalContext::new(self.gecx);
214 let return_ptr = match mir.return_ty {
215 ty::FnConverging(ty) => {
216 let size = nested_fecx.type_size(ty);
217 Some(nested_fecx.memory.allocate(size))
219 ty::FnDiverging => None,
222 let substs = nested_fecx.substs();
223 nested_fecx.push_stack_frame(CachedMir::Ref(mir), substs, return_ptr);
228 fn push_stack_frame(&mut self, mir: CachedMir<'mir, 'tcx>, substs: &'tcx Substs<'tcx>,
229 return_ptr: Option<Pointer>)
231 self.substs_stack.push(substs);
233 let arg_tys = mir.arg_decls.iter().map(|a| a.ty);
234 let var_tys = mir.var_decls.iter().map(|v| v.ty);
235 let temp_tys = mir.temp_decls.iter().map(|t| t.ty);
237 let locals: Vec<Pointer> = arg_tys.chain(var_tys).chain(temp_tys).map(|ty| {
238 let size = self.type_size(ty);
239 self.memory.allocate(size)
242 let num_args = mir.arg_decls.len();
243 let num_vars = mir.var_decls.len();
245 self.stack.push(Frame {
247 next_block: mir::START_BLOCK,
248 return_ptr: return_ptr,
250 var_offset: num_args,
251 temp_offset: num_args + num_vars,
255 fn pop_stack_frame(&mut self) {
256 let _frame = self.stack.pop().expect("tried to pop a stack frame, but there were none");
257 // TODO(solson): Deallocate local variables.
258 self.substs_stack.pop();
261 fn eval_terminator(&mut self, terminator: &mir::Terminator<'tcx>)
262 -> EvalResult<TerminatorTarget> {
263 use rustc::mir::repr::TerminatorKind::*;
264 let target = match terminator.kind {
265 Return => TerminatorTarget::Return,
267 Goto { target } => TerminatorTarget::Block(target),
269 If { ref cond, targets: (then_target, else_target) } => {
270 let cond_ptr = self.eval_operand(cond)?;
271 let cond_val = self.memory.read_bool(cond_ptr)?;
272 TerminatorTarget::Block(if cond_val { then_target } else { else_target })
275 SwitchInt { ref discr, ref values, ref targets, .. } => {
276 let discr_ptr = self.eval_lvalue(discr)?.to_ptr();
277 let discr_size = self
278 .type_layout(self.lvalue_ty(discr))
279 .size(&self.tcx.data_layout)
281 let discr_val = self.memory.read_uint(discr_ptr, discr_size)?;
283 // Branch to the `otherwise` case by default, if no match is found.
284 let mut target_block = targets[targets.len() - 1];
286 for (index, val_const) in values.iter().enumerate() {
287 let ptr = self.const_to_ptr(val_const)?;
288 let val = self.memory.read_uint(ptr, discr_size)?;
289 if discr_val == val {
290 target_block = targets[index];
295 TerminatorTarget::Block(target_block)
298 Switch { ref discr, ref targets, adt_def } => {
299 let adt_ptr = self.eval_lvalue(discr)?.to_ptr();
300 let adt_layout = self.type_layout(self.lvalue_ty(discr));
303 Layout::General { discr, .. } | Layout::CEnum { discr, .. } => {
304 let discr_size = discr.size().bytes();
305 let discr_val = self.memory.read_uint(adt_ptr, discr_size as usize)?;
307 let matching = adt_def.variants.iter()
308 .position(|v| discr_val == v.disr_val.to_u64_unchecked());
311 Some(i) => TerminatorTarget::Block(targets[i]),
312 None => return Err(EvalError::InvalidDiscriminant),
316 Layout::RawNullablePointer { nndiscr, .. } => {
317 let is_null = match self.memory.read_usize(adt_ptr) {
319 Ok(_) | Err(EvalError::ReadPointerAsBytes) => false,
320 Err(e) => return Err(e),
323 assert!(nndiscr == 0 || nndiscr == 1);
324 let target = if is_null { 1 - nndiscr } else { nndiscr };
325 TerminatorTarget::Block(targets[target as usize])
328 _ => panic!("attempted to switch on non-aggregate type"),
332 Call { ref func, ref args, ref destination, .. } => {
333 let mut return_ptr = None;
334 if let Some((ref lv, target)) = *destination {
335 self.frame_mut().next_block = target;
336 return_ptr = Some(self.eval_lvalue(lv)?.to_ptr());
339 let func_ty = self.operand_ty(func);
341 ty::TyFnDef(def_id, substs, fn_ty) => {
342 use syntax::abi::Abi;
344 Abi::RustIntrinsic => {
345 let name = self.tcx.item_name(def_id).as_str();
346 match fn_ty.sig.0.output {
347 ty::FnConverging(ty) => {
348 let size = self.type_size(ty);
349 self.call_intrinsic(&name, substs, args,
350 return_ptr.unwrap(), size)?
352 ty::FnDiverging => unimplemented!(),
356 Abi::C => self.call_c_abi(def_id, args, return_ptr.unwrap())?,
358 Abi::Rust | Abi::RustCall => {
359 // TODO(solson): Adjust the first argument when calling a Fn or
360 // FnMut closure via FnOnce::call_once.
362 // Only trait methods can have a Self parameter.
363 let (resolved_def_id, resolved_substs) = if substs.self_ty().is_some() {
364 self.trait_method(def_id, substs)
369 let mut arg_srcs = Vec::new();
371 let src = self.eval_operand(arg)?;
372 let src_ty = self.operand_ty(arg);
373 arg_srcs.push((src, src_ty));
376 if fn_ty.abi == Abi::RustCall && !args.is_empty() {
378 let last_arg = args.last().unwrap();
379 let last = self.eval_operand(last_arg)?;
380 let last_ty = self.operand_ty(last_arg);
381 let last_layout = self.type_layout(last_ty);
382 match (&last_ty.sty, last_layout) {
383 (&ty::TyTuple(ref fields),
384 &Layout::Univariant { ref variant, .. }) => {
385 let offsets = iter::once(0)
386 .chain(variant.offset_after_field.iter()
387 .map(|s| s.bytes()));
388 for (offset, ty) in offsets.zip(fields) {
389 let src = last.offset(offset as isize);
390 arg_srcs.push((src, ty));
393 ty => panic!("expected tuple as last argument in function with 'rust-call' ABI, got {:?}", ty),
397 let mir = self.load_mir(resolved_def_id);
398 self.name_stack.push((def_id, substs, terminator.span));
399 self.push_stack_frame(mir, resolved_substs, return_ptr);
401 for (i, (src, src_ty)) in arg_srcs.into_iter().enumerate() {
402 let dest = self.frame().locals[i];
403 self.move_(src, dest, src_ty)?;
406 TerminatorTarget::Call
409 abi => panic!("can't handle function with {:?} ABI", abi),
413 _ => panic!("can't handle callee of type {:?}", func_ty),
417 Drop { ref value, target, .. } => {
418 let ptr = self.eval_lvalue(value)?.to_ptr();
419 let ty = self.lvalue_ty(value);
421 TerminatorTarget::Block(target)
424 Resume => unimplemented!(),
430 fn drop(&mut self, ptr: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<()> {
431 if !self.type_needs_drop(ty) {
432 self.log(1, || print!("no need to drop {:?}", ty));
435 self.log(1, || print!("need to drop {:?}", ty));
437 // TODO(solson): Call user-defined Drop::drop impls.
440 ty::TyBox(contents_ty) => {
441 match self.memory.read_ptr(ptr) {
442 Ok(contents_ptr) => {
443 self.drop(contents_ptr, contents_ty)?;
444 self.log(1, || print!("deallocating box"));
445 self.memory.deallocate(contents_ptr)?;
447 Err(EvalError::ReadBytesAsPointer) => {
448 let size = self.memory.pointer_size;
449 let possible_drop_fill = self.memory.read_bytes(ptr, size)?;
450 if possible_drop_fill.iter().all(|&b| b == mem::POST_DROP_U8) {
453 return Err(EvalError::ReadBytesAsPointer);
456 Err(e) => return Err(e),
460 // TODO(solson): Implement drop for other relevant types (e.g. aggregates).
465 // FIXME(solson): Trait objects (with no static size) probably get filled, too.
466 let size = self.type_size(ty);
467 self.memory.drop_fill(ptr, size)?;
475 substs: &'tcx Substs<'tcx>,
476 args: &[mir::Operand<'tcx>],
479 ) -> EvalResult<TerminatorTarget> {
480 let args_res: EvalResult<Vec<Pointer>> = args.iter()
481 .map(|arg| self.eval_operand(arg))
483 let args = args_res?;
488 "copy_nonoverlapping" => {
489 let elem_ty = *substs.types.get(subst::FnSpace, 0);
490 let elem_size = self.type_size(elem_ty);
491 let src = self.memory.read_ptr(args[0])?;
492 let dest = self.memory.read_ptr(args[1])?;
493 let count = self.memory.read_isize(args[2])?;
494 self.memory.copy(src, dest, count as usize * elem_size)?;
498 let arg_ty = *substs.types.get(subst::FnSpace, 0);
499 let arg_size = self.type_size(arg_ty);
500 self.memory.drop_fill(args[0], arg_size)?;
503 "init" => self.memory.write_repeat(dest, 0, dest_size)?,
506 self.memory.write_int(dest, 1, dest_size)?;
510 let ty = *substs.types.get(subst::FnSpace, 0);
511 let ptr = self.memory.read_ptr(args[0])?;
512 self.move_(args[1], ptr, ty)?;
515 // FIXME(solson): Handle different integer types correctly.
516 "add_with_overflow" => {
517 let ty = *substs.types.get(subst::FnSpace, 0);
518 let size = self.type_size(ty);
519 let left = self.memory.read_int(args[0], size)?;
520 let right = self.memory.read_int(args[1], size)?;
521 let (n, overflowed) = unsafe {
522 ::std::intrinsics::add_with_overflow::<i64>(left, right)
524 self.memory.write_int(dest, n, size)?;
525 self.memory.write_bool(dest.offset(size as isize), overflowed)?;
528 // FIXME(solson): Handle different integer types correctly.
529 "mul_with_overflow" => {
530 let ty = *substs.types.get(subst::FnSpace, 0);
531 let size = self.type_size(ty);
532 let left = self.memory.read_int(args[0], size)?;
533 let right = self.memory.read_int(args[1], size)?;
534 let (n, overflowed) = unsafe {
535 ::std::intrinsics::mul_with_overflow::<i64>(left, right)
537 self.memory.write_int(dest, n, size)?;
538 self.memory.write_bool(dest.offset(size as isize), overflowed)?;
542 let pointee_ty = *substs.types.get(subst::FnSpace, 0);
543 let pointee_size = self.type_size(pointee_ty) as isize;
544 let ptr_arg = args[0];
545 let offset = self.memory.read_isize(args[1])?;
547 match self.memory.read_ptr(ptr_arg) {
549 let result_ptr = ptr.offset(offset as isize * pointee_size);
550 self.memory.write_ptr(dest, result_ptr)?;
552 Err(EvalError::ReadBytesAsPointer) => {
553 let addr = self.memory.read_isize(ptr_arg)?;
554 let result_addr = addr + offset * pointee_size as i64;
555 self.memory.write_isize(dest, result_addr)?;
557 Err(e) => return Err(e),
561 // FIXME(solson): Handle different integer types correctly. Use primvals?
562 "overflowing_sub" => {
563 let ty = *substs.types.get(subst::FnSpace, 0);
564 let size = self.type_size(ty);
565 let left = self.memory.read_int(args[0], size)?;
566 let right = self.memory.read_int(args[1], size)?;
567 let n = left.wrapping_sub(right);
568 self.memory.write_int(dest, n, size)?;
572 let ty = *substs.types.get(subst::FnSpace, 0);
573 let size = self.type_size(ty) as u64;
574 self.memory.write_uint(dest, size, dest_size)?;
578 let ty = *substs.types.get(subst::FnSpace, 0);
579 if self.type_is_sized(ty) {
580 let size = self.type_size(ty) as u64;
581 self.memory.write_uint(dest, size, dest_size)?;
584 ty::TySlice(_) | ty::TyStr => {
585 let elem_ty = ty.sequence_element_type(self.tcx);
586 let elem_size = self.type_size(elem_ty) as u64;
587 let ptr_size = self.memory.pointer_size as isize;
588 let n = self.memory.read_usize(args[0].offset(ptr_size))?;
589 self.memory.write_uint(dest, n * elem_size, dest_size)?;
592 _ => panic!("unimplemented: size_of_val::<{:?}>", ty),
598 let ty = *substs.types.get(subst::FnSpace, 0);
599 self.move_(args[0], dest, ty)?;
601 "uninit" => self.memory.mark_definedness(dest, dest_size, false)?,
603 name => panic!("can't handle intrinsic: {}", name),
606 // Since we pushed no stack frame, the main loop will act
607 // as if the call just completed and it's returning to the
609 Ok(TerminatorTarget::Call)
615 args: &[mir::Operand<'tcx>],
617 ) -> EvalResult<TerminatorTarget> {
618 let name = self.tcx.item_name(def_id);
619 let attrs = self.tcx.get_attrs(def_id);
620 let link_name = match attr::first_attr_value_str_by_name(&attrs, "link_name") {
621 Some(ln) => ln.clone(),
622 None => name.as_str(),
625 let args_res: EvalResult<Vec<Pointer>> = args.iter()
626 .map(|arg| self.eval_operand(arg))
628 let args = args_res?;
630 match &link_name[..] {
631 "__rust_allocate" => {
632 let size = self.memory.read_usize(args[0])?;
633 let ptr = self.memory.allocate(size as usize);
634 self.memory.write_ptr(dest, ptr)?;
637 "__rust_reallocate" => {
638 let ptr = self.memory.read_ptr(args[0])?;
639 let size = self.memory.read_usize(args[2])?;
640 self.memory.reallocate(ptr, size as usize)?;
641 self.memory.write_ptr(dest, ptr)?;
644 _ => panic!("can't call C ABI function: {}", link_name),
647 // Since we pushed no stack frame, the main loop will act
648 // as if the call just completed and it's returning to the
650 Ok(TerminatorTarget::Call)
653 fn assign_fields<I: IntoIterator<Item = u64>>(
657 operands: &[mir::Operand<'tcx>],
658 ) -> EvalResult<()> {
659 for (offset, operand) in offsets.into_iter().zip(operands) {
660 let src = self.eval_operand(operand)?;
661 let src_ty = self.operand_ty(operand);
662 let field_dest = dest.offset(offset as isize);
663 self.move_(src, field_dest, src_ty)?;
668 fn eval_assignment(&mut self, lvalue: &mir::Lvalue<'tcx>, rvalue: &mir::Rvalue<'tcx>)
671 let dest = self.eval_lvalue(lvalue)?.to_ptr();
672 let dest_ty = self.lvalue_ty(lvalue);
673 let dest_layout = self.type_layout(dest_ty);
675 use rustc::mir::repr::Rvalue::*;
677 Use(ref operand) => {
678 let src = self.eval_operand(operand)?;
679 self.move_(src, dest, dest_ty)?;
682 BinaryOp(bin_op, ref left, ref right) => {
683 let left_ptr = self.eval_operand(left)?;
684 let left_ty = self.operand_ty(left);
685 let left_val = self.read_primval(left_ptr, left_ty)?;
687 let right_ptr = self.eval_operand(right)?;
688 let right_ty = self.operand_ty(right);
689 let right_val = self.read_primval(right_ptr, right_ty)?;
691 let val = primval::binary_op(bin_op, left_val, right_val)?;
692 self.memory.write_primval(dest, val)?;
695 UnaryOp(un_op, ref operand) => {
696 let ptr = self.eval_operand(operand)?;
697 let ty = self.operand_ty(operand);
698 let val = self.read_primval(ptr, ty)?;
699 self.memory.write_primval(dest, primval::unary_op(un_op, val))?;
702 Aggregate(ref kind, ref operands) => {
703 use rustc::ty::layout::Layout::*;
705 Univariant { ref variant, .. } => {
706 let offsets = iter::once(0)
707 .chain(variant.offset_after_field.iter().map(|s| s.bytes()));
708 self.assign_fields(dest, offsets, operands)?;
712 let elem_size = match dest_ty.sty {
713 ty::TyArray(elem_ty, _) => self.type_size(elem_ty) as u64,
714 _ => panic!("tried to assign {:?} to non-array type {:?}",
717 let offsets = (0..).map(|i| i * elem_size);
718 self.assign_fields(dest, offsets, operands)?;
721 General { discr, ref variants, .. } => {
722 if let mir::AggregateKind::Adt(adt_def, variant, _) = *kind {
723 let discr_val = adt_def.variants[variant].disr_val.to_u64_unchecked();
724 let discr_size = discr.size().bytes() as usize;
725 self.memory.write_uint(dest, discr_val, discr_size)?;
727 let offsets = variants[variant].offset_after_field.iter()
729 self.assign_fields(dest, offsets, operands)?;
731 panic!("tried to assign {:?} to Layout::General", kind);
735 RawNullablePointer { nndiscr, .. } => {
736 if let mir::AggregateKind::Adt(_, variant, _) = *kind {
737 if nndiscr == variant as u64 {
738 assert_eq!(operands.len(), 1);
739 let operand = &operands[0];
740 let src = self.eval_operand(operand)?;
741 let src_ty = self.operand_ty(operand);
742 self.move_(src, dest, src_ty)?;
744 assert_eq!(operands.len(), 0);
745 self.memory.write_isize(dest, 0)?;
748 panic!("tried to assign {:?} to Layout::RawNullablePointer", kind);
752 CEnum { discr, signed, .. } => {
753 assert_eq!(operands.len(), 0);
754 if let mir::AggregateKind::Adt(adt_def, variant, _) = *kind {
755 let val = adt_def.variants[variant].disr_val.to_u64_unchecked();
756 let size = discr.size().bytes() as usize;
759 self.memory.write_int(dest, val as i64, size)?;
761 self.memory.write_uint(dest, val, size)?;
764 panic!("tried to assign {:?} to Layout::CEnum", kind);
768 _ => panic!("can't handle destination layout {:?} when assigning {:?}",
773 Repeat(ref operand, _) => {
774 let (elem_size, length) = match dest_ty.sty {
775 ty::TyArray(elem_ty, n) => (self.type_size(elem_ty), n),
776 _ => panic!("tried to assign array-repeat to non-array type {:?}", dest_ty),
779 let src = self.eval_operand(operand)?;
781 let elem_dest = dest.offset((i * elem_size) as isize);
782 self.memory.copy(src, elem_dest, elem_size)?;
787 let src = self.eval_lvalue(lvalue)?;
788 let ty = self.lvalue_ty(lvalue);
789 let len = match ty.sty {
790 ty::TyArray(_, n) => n as u64,
791 ty::TySlice(_) => if let LvalueExtra::Length(n) = src.extra {
794 panic!("Rvalue::Len of a slice given non-slice pointer: {:?}", src);
796 _ => panic!("Rvalue::Len expected array or slice, got {:?}", ty),
798 self.memory.write_usize(dest, len)?;
801 Ref(_, _, ref lvalue) => {
802 let lv = self.eval_lvalue(lvalue)?;
803 self.memory.write_ptr(dest, lv.ptr)?;
805 LvalueExtra::None => {},
806 LvalueExtra::Length(len) => {
807 let len_ptr = dest.offset(self.memory.pointer_size as isize);
808 self.memory.write_usize(len_ptr, len)?;
810 LvalueExtra::DowncastVariant(..) =>
811 panic!("attempted to take a reference to an enum downcast lvalue"),
816 let size = self.type_size(ty);
817 let ptr = self.memory.allocate(size);
818 self.memory.write_ptr(dest, ptr)?;
821 Cast(kind, ref operand, dest_ty) => {
822 let src = self.eval_operand(operand)?;
823 let src_ty = self.operand_ty(operand);
825 use rustc::mir::repr::CastKind::*;
828 self.move_(src, dest, src_ty)?;
829 let src_pointee_ty = pointee_type(src_ty).unwrap();
830 let dest_pointee_ty = pointee_type(dest_ty).unwrap();
832 match (&src_pointee_ty.sty, &dest_pointee_ty.sty) {
833 (&ty::TyArray(_, length), &ty::TySlice(_)) => {
834 let len_ptr = dest.offset(self.memory.pointer_size as isize);
835 self.memory.write_usize(len_ptr, length as u64)?;
838 _ => panic!("can't handle cast: {:?}", rvalue),
843 // FIXME(solson): Wrong for almost everything.
844 let size = dest_layout.size(&self.tcx.data_layout).bytes() as usize;
845 self.memory.copy(src, dest, size)?;
848 _ => panic!("can't handle cast: {:?}", rvalue),
852 Slice { .. } => unimplemented!(),
853 InlineAsm { .. } => unimplemented!(),
859 fn eval_operand(&mut self, op: &mir::Operand<'tcx>) -> EvalResult<Pointer> {
860 use rustc::mir::repr::Operand::*;
862 Consume(ref lvalue) => Ok(self.eval_lvalue(lvalue)?.to_ptr()),
863 Constant(mir::Constant { ref literal, .. }) => {
864 use rustc::mir::repr::Literal::*;
866 Value { ref value } => Ok(self.const_to_ptr(value)?),
867 Item { .. } => unimplemented!(),
868 Promoted { index } => {
869 // TODO(solson): Mark constants and statics as read-only and cache their
871 let current_mir = self.mir();
872 let mir = ¤t_mir.promoted[index];
873 self.call_nested(mir).map(Option::unwrap)
880 fn eval_lvalue(&mut self, lvalue: &mir::Lvalue<'tcx>) -> EvalResult<Lvalue> {
881 use rustc::mir::repr::Lvalue::*;
882 let ptr = match *lvalue {
883 ReturnPointer => self.frame().return_ptr
884 .expect("ReturnPointer used in a function with no return value"),
885 Arg(i) => self.frame().locals[i as usize],
886 Var(i) => self.frame().locals[self.frame().var_offset + i as usize],
887 Temp(i) => self.frame().locals[self.frame().temp_offset + i as usize],
890 // TODO(solson): Mark constants and statics as read-only and cache their values.
891 let mir = self.load_mir(def_id);
892 self.call_nested(&mir)?.unwrap()
895 Projection(ref proj) => {
896 let base = self.eval_lvalue(&proj.base)?;
897 let base_ty = self.lvalue_ty(&proj.base);
898 let base_layout = self.type_layout(base_ty);
900 use rustc::mir::repr::ProjectionElem::*;
903 let variant = match *base_layout {
904 Layout::Univariant { ref variant, .. } => variant,
905 Layout::General { ref variants, .. } => {
906 if let LvalueExtra::DowncastVariant(variant_idx) = base.extra {
907 &variants[variant_idx]
909 panic!("field access on enum had no variant index");
912 Layout::RawNullablePointer { .. } => {
913 assert_eq!(field.index(), 0);
916 _ => panic!("field access on non-product type: {:?}", base_layout),
919 let offset = variant.field_offset(field.index()).bytes();
920 base.ptr.offset(offset as isize)
923 Downcast(_, variant) => match *base_layout {
924 Layout::General { discr, .. } => {
926 ptr: base.ptr.offset(discr.size().bytes() as isize),
927 extra: LvalueExtra::DowncastVariant(variant),
930 Layout::RawNullablePointer { .. } => return Ok(base),
931 _ => panic!("variant downcast on non-aggregate type: {:?}", base_layout),
935 let pointee_ty = pointee_type(base_ty).expect("Deref of non-pointer");
936 let ptr = self.memory.read_ptr(base.ptr)?;
937 let extra = match pointee_ty.sty {
938 ty::TySlice(_) | ty::TyStr => {
939 let len_ptr = base.ptr.offset(self.memory.pointer_size as isize);
940 let len = self.memory.read_usize(len_ptr)?;
941 LvalueExtra::Length(len)
943 ty::TyTrait(_) => unimplemented!(),
944 _ => LvalueExtra::None,
946 return Ok(Lvalue { ptr: ptr, extra: extra });
949 Index(ref operand) => {
950 let elem_size = match base_ty.sty {
951 ty::TyArray(elem_ty, _) |
952 ty::TySlice(elem_ty) => self.type_size(elem_ty),
953 _ => panic!("indexing expected an array or slice, got {:?}", base_ty),
955 let n_ptr = self.eval_operand(operand)?;
956 let n = self.memory.read_usize(n_ptr)?;
957 base.ptr.offset(n as isize * elem_size as isize)
960 ConstantIndex { .. } => unimplemented!(),
965 Ok(Lvalue { ptr: ptr, extra: LvalueExtra::None })
968 // TODO(solson): Try making const_to_primval instead.
969 fn const_to_ptr(&mut self, const_val: &const_val::ConstVal) -> EvalResult<Pointer> {
970 use rustc::middle::const_val::ConstVal::*;
972 Float(_f) => unimplemented!(),
974 // TODO(solson): Check int constant type.
975 let ptr = self.memory.allocate(8);
976 self.memory.write_uint(ptr, int.to_u64_unchecked(), 8)?;
980 let psize = self.memory.pointer_size;
981 let static_ptr = self.memory.allocate(s.len());
982 let ptr = self.memory.allocate(psize * 2);
983 self.memory.write_bytes(static_ptr, s.as_bytes())?;
984 self.memory.write_ptr(ptr, static_ptr)?;
985 self.memory.write_usize(ptr.offset(psize as isize), s.len() as u64)?;
989 let psize = self.memory.pointer_size;
990 let static_ptr = self.memory.allocate(bs.len());
991 let ptr = self.memory.allocate(psize);
992 self.memory.write_bytes(static_ptr, bs)?;
993 self.memory.write_ptr(ptr, static_ptr)?;
997 let ptr = self.memory.allocate(1);
998 self.memory.write_bool(ptr, b)?;
1001 Char(_c) => unimplemented!(),
1002 Struct(_node_id) => unimplemented!(),
1003 Tuple(_node_id) => unimplemented!(),
1004 Function(_def_id) => unimplemented!(),
1005 Array(_, _) => unimplemented!(),
1006 Repeat(_, _) => unimplemented!(),
1007 Dummy => unimplemented!(),
1011 fn lvalue_ty(&self, lvalue: &mir::Lvalue<'tcx>) -> ty::Ty<'tcx> {
1012 self.monomorphize(self.mir().lvalue_ty(self.tcx, lvalue).to_ty(self.tcx))
1015 fn operand_ty(&self, operand: &mir::Operand<'tcx>) -> ty::Ty<'tcx> {
1016 self.monomorphize(self.mir().operand_ty(self.tcx, operand))
1019 fn monomorphize(&self, ty: ty::Ty<'tcx>) -> ty::Ty<'tcx> {
1020 let substituted = ty.subst(self.tcx, self.substs());
1021 infer::normalize_associated_type(self.tcx, &substituted)
1024 fn type_needs_drop(&self, ty: ty::Ty<'tcx>) -> bool {
1025 self.tcx.type_needs_drop_given_env(ty, &self.tcx.empty_parameter_environment())
1028 fn move_(&mut self, src: Pointer, dest: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<()> {
1029 let size = self.type_size(ty);
1030 self.memory.copy(src, dest, size)?;
1031 if self.type_needs_drop(ty) {
1032 self.memory.drop_fill(src, size)?;
1037 fn type_is_sized(&self, ty: ty::Ty<'tcx>) -> bool {
1038 ty.is_sized(&self.tcx.empty_parameter_environment(), DUMMY_SP)
1041 fn type_size(&self, ty: ty::Ty<'tcx>) -> usize {
1042 self.type_layout(ty).size(&self.tcx.data_layout).bytes() as usize
1045 fn type_layout(&self, ty: ty::Ty<'tcx>) -> &'tcx Layout {
1046 // TODO(solson): Is this inefficient? Needs investigation.
1047 let ty = self.monomorphize(ty);
1049 let infcx = infer::normalizing_infer_ctxt(self.tcx, &self.tcx.tables, ProjectionMode::Any);
1051 // TODO(solson): Report this error properly.
1052 ty.layout(&infcx).unwrap()
1055 pub fn read_primval(&mut self, ptr: Pointer, ty: ty::Ty<'tcx>) -> EvalResult<PrimVal> {
1056 use syntax::ast::{IntTy, UintTy};
1057 let val = match ty.sty {
1058 ty::TyBool => PrimVal::Bool(self.memory.read_bool(ptr)?),
1059 ty::TyInt(IntTy::I8) => PrimVal::I8(self.memory.read_int(ptr, 1)? as i8),
1060 ty::TyInt(IntTy::I16) => PrimVal::I16(self.memory.read_int(ptr, 2)? as i16),
1061 ty::TyInt(IntTy::I32) => PrimVal::I32(self.memory.read_int(ptr, 4)? as i32),
1062 ty::TyInt(IntTy::I64) => PrimVal::I64(self.memory.read_int(ptr, 8)? as i64),
1063 ty::TyUint(UintTy::U8) => PrimVal::U8(self.memory.read_uint(ptr, 1)? as u8),
1064 ty::TyUint(UintTy::U16) => PrimVal::U16(self.memory.read_uint(ptr, 2)? as u16),
1065 ty::TyUint(UintTy::U32) => PrimVal::U32(self.memory.read_uint(ptr, 4)? as u32),
1066 ty::TyUint(UintTy::U64) => PrimVal::U64(self.memory.read_uint(ptr, 8)? as u64),
1068 // TODO(solson): Pick the PrimVal dynamically.
1069 ty::TyInt(IntTy::Is) => PrimVal::I64(self.memory.read_isize(ptr)?),
1070 ty::TyUint(UintTy::Us) => PrimVal::U64(self.memory.read_usize(ptr)?),
1072 ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
1073 ty::TyRawPtr(ty::TypeAndMut { ty, .. }) => {
1074 if self.type_is_sized(ty) {
1075 match self.memory.read_ptr(ptr) {
1076 Ok(p) => PrimVal::AbstractPtr(p),
1077 Err(EvalError::ReadBytesAsPointer) => {
1078 PrimVal::IntegerPtr(self.memory.read_usize(ptr)?)
1080 Err(e) => return Err(e),
1083 panic!("unimplemented: primitive read of fat pointer type: {:?}", ty);
1087 _ => panic!("primitive read of non-primitive type: {:?}", ty),
1092 fn frame(&self) -> &Frame<'mir, 'tcx> {
1093 self.stack.last().expect("no call frames exist")
1096 fn frame_mut(&mut self) -> &mut Frame<'mir, 'tcx> {
1097 self.stack.last_mut().expect("no call frames exist")
1100 fn mir(&self) -> CachedMir<'mir, 'tcx> {
1101 self.frame().mir.clone()
1104 fn substs(&self) -> &'tcx Substs<'tcx> {
1105 self.substs_stack.last().cloned().unwrap_or_else(|| self.tcx.mk_substs(Substs::empty()))
1108 fn load_mir(&self, def_id: DefId) -> CachedMir<'mir, 'tcx> {
1109 match self.tcx.map.as_local_node_id(def_id) {
1110 Some(node_id) => CachedMir::Ref(self.mir_map.map.get(&node_id).unwrap()),
1112 let mut mir_cache = self.mir_cache.borrow_mut();
1113 if let Some(mir) = mir_cache.get(&def_id) {
1114 return CachedMir::Owned(mir.clone());
1117 let cs = &self.tcx.sess.cstore;
1118 let mir = cs.maybe_get_item_mir(self.tcx, def_id).unwrap_or_else(|| {
1119 panic!("no mir for {:?}", def_id);
1121 let cached = Rc::new(mir);
1122 mir_cache.insert(def_id, cached.clone());
1123 CachedMir::Owned(cached)
1128 fn fulfill_obligation(&self, trait_ref: ty::PolyTraitRef<'tcx>) -> traits::Vtable<'tcx, ()> {
1129 // Do the initial selection for the obligation. This yields the shallow result we are
1130 // looking for -- that is, what specific impl.
1131 let infcx = infer::normalizing_infer_ctxt(self.tcx, &self.tcx.tables, ProjectionMode::Any);
1132 let mut selcx = traits::SelectionContext::new(&infcx);
1134 let obligation = traits::Obligation::new(
1135 traits::ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID),
1136 trait_ref.to_poly_trait_predicate(),
1138 let selection = selcx.select(&obligation).unwrap().unwrap();
1140 // Currently, we use a fulfillment context to completely resolve all nested obligations.
1141 // This is because they can inform the inference of the impl's type parameters.
1142 let mut fulfill_cx = traits::FulfillmentContext::new();
1143 let vtable = selection.map(|predicate| {
1144 fulfill_cx.register_predicate_obligation(&infcx, predicate);
1146 infer::drain_fulfillment_cx_or_panic(
1147 DUMMY_SP, &infcx, &mut fulfill_cx, &vtable
1151 /// Trait method, which has to be resolved to an impl method.
1152 pub fn trait_method(&self, def_id: DefId, substs: &'tcx Substs<'tcx>)
1153 -> (DefId, &'tcx Substs<'tcx>)
1155 let method_item = self.tcx.impl_or_trait_item(def_id);
1156 let trait_id = method_item.container().id();
1157 let trait_ref = ty::Binder(substs.to_trait_ref(self.tcx, trait_id));
1158 match self.fulfill_obligation(trait_ref) {
1159 traits::VtableImpl(vtable_impl) => {
1160 let impl_did = vtable_impl.impl_def_id;
1161 let mname = self.tcx.item_name(def_id);
1162 // Create a concatenated set of substitutions which includes those from the impl
1163 // and those from the method:
1164 let impl_substs = vtable_impl.substs.with_method_from(substs);
1165 let substs = self.tcx.mk_substs(impl_substs);
1166 let mth = get_impl_method(self.tcx, impl_did, substs, mname);
1168 (mth.method.def_id, mth.substs)
1171 traits::VtableClosure(vtable_closure) =>
1172 (vtable_closure.closure_def_id, vtable_closure.substs.func_substs),
1174 traits::VtableFnPointer(_fn_ty) => {
1175 let _trait_closure_kind = self.tcx.lang_items.fn_trait_kind(trait_id).unwrap();
1177 // let llfn = trans_fn_pointer_shim(ccx, trait_closure_kind, fn_ty);
1179 // let method_ty = def_ty(tcx, def_id, substs);
1180 // let fn_ptr_ty = match method_ty.sty {
1181 // ty::TyFnDef(_, _, fty) => tcx.mk_ty(ty::TyFnPtr(fty)),
1182 // _ => unreachable!("expected fn item type, found {}",
1185 // Callee::ptr(immediate_rvalue(llfn, fn_ptr_ty))
1188 traits::VtableObject(ref _data) => {
1191 // data: Virtual(traits::get_vtable_index_of_object_method(
1192 // tcx, data, def_id)),
1193 // ty: def_ty(tcx, def_id, substs)
1196 vtable => unreachable!("resolved vtable bad vtable {:?} in trans", vtable),
1201 fn pointee_type(ptr_ty: ty::Ty) -> Option<ty::Ty> {
1203 ty::TyRef(_, ty::TypeAndMut { ty, .. }) |
1204 ty::TyRawPtr(ty::TypeAndMut { ty, .. }) |
1213 fn to_ptr(self) -> Pointer {
1214 assert_eq!(self.extra, LvalueExtra::None);
1219 impl<'mir, 'tcx: 'mir> Deref for CachedMir<'mir, 'tcx> {
1220 type Target = mir::Mir<'tcx>;
1221 fn deref(&self) -> &mir::Mir<'tcx> {
1223 CachedMir::Ref(r) => r,
1224 CachedMir::Owned(ref rc) => &rc,
1230 pub struct ImplMethod<'tcx> {
1231 pub method: Rc<ty::Method<'tcx>>,
1232 pub substs: &'tcx Substs<'tcx>,
1233 pub is_provided: bool,
1236 /// Locates the applicable definition of a method, given its name.
1237 pub fn get_impl_method<'tcx>(
1240 substs: &'tcx Substs<'tcx>,
1242 ) -> ImplMethod<'tcx> {
1243 assert!(!substs.types.needs_infer());
1245 let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
1246 let trait_def = tcx.lookup_trait_def(trait_def_id);
1247 let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables, ProjectionMode::Any);
1249 match trait_def.ancestors(impl_def_id).fn_defs(tcx, name).next() {
1250 Some(node_item) => {
1252 method: node_item.item,
1253 substs: traits::translate_substs(&infcx, impl_def_id, substs, node_item.node),
1254 is_provided: node_item.node.is_from_trait(),
1258 bug!("method {:?} not found in {:?}", name, impl_def_id);
1263 pub fn interpret_start_points<'tcx>(tcx: &TyCtxt<'tcx>, mir_map: &MirMap<'tcx>) {
1264 for (&id, mir) in &mir_map.map {
1265 for attr in tcx.map.attrs(id) {
1266 use syntax::attr::AttrMetaMethods;
1267 if attr.check_name("miri_run") {
1268 let item = tcx.map.expect_item(id);
1270 println!("Interpreting: {}", item.name);
1272 let mut gecx = GlobalEvalContext::new(tcx, mir_map);
1273 let mut fecx = FnEvalContext::new(&mut gecx);
1274 match fecx.call_nested(mir) {
1275 Ok(Some(return_ptr)) => fecx.memory.dump(return_ptr.alloc_id),
1276 Ok(None) => println!("(diverging function returned)"),
1278 // TODO(solson): Detect whether the error was already reported or not.
1279 // tcx.sess.err(&e.to_string());
1289 // TODO(solson): Upstream these methods into rustc::ty::layout.
1292 fn size(self) -> Size;
1295 impl IntegerExt for layout::Integer {
1296 fn size(self) -> Size {
1297 use rustc::ty::layout::Integer::*;
1299 I1 | I8 => Size::from_bits(8),
1300 I16 => Size::from_bits(16),
1301 I32 => Size::from_bits(32),
1302 I64 => Size::from_bits(64),
1308 fn field_offset(&self, index: usize) -> Size;
1311 impl StructExt for layout::Struct {
1312 fn field_offset(&self, index: usize) -> Size {
1316 self.offset_after_field[index - 1]