2 use crate::build::scope::DropKind;
3 use crate::thir::cx::Cx;
4 use crate::thir::{BindingMode, LintLevel, PatKind};
5 use rustc_attr::{self as attr, UnwindAttr};
6 use rustc_errors::ErrorReported;
8 use rustc_hir::def_id::{DefId, LocalDefId};
9 use rustc_hir::lang_items::LangItem;
10 use rustc_hir::{GeneratorKind, HirIdMap, Node};
11 use rustc_index::vec::{Idx, IndexVec};
12 use rustc_infer::infer::TyCtxtInferExt;
13 use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
14 use rustc_middle::middle::region;
15 use rustc_middle::mir::*;
16 use rustc_middle::ty::subst::Subst;
17 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
18 use rustc_span::symbol::kw;
20 use rustc_target::spec::abi::Abi;
21 use rustc_target::spec::PanicStrategy;
25 crate fn mir_built<'tcx>(
27 def: ty::WithOptConstParam<LocalDefId>,
28 ) -> &'tcx rustc_data_structures::steal::Steal<Body<'tcx>> {
29 if let Some(def) = def.try_upgrade(tcx) {
30 return tcx.mir_built(def);
33 let mut body = mir_build(tcx, def);
34 if def.const_param_did.is_some() {
35 assert!(matches!(body.source.instance, ty::InstanceDef::Item(_)));
36 body.source = MirSource::from_instance(ty::InstanceDef::Item(def.to_global()));
39 tcx.alloc_steal_mir(body)
42 /// Construct the MIR for a given `DefId`.
43 fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
44 let id = tcx.hir().local_def_id_to_hir_id(def.did);
46 // Figure out what primary body this item has.
47 let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
48 Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) => {
49 (*body_id, decl.output.span(), None)
51 Node::Item(hir::Item {
52 kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
56 | Node::ImplItem(hir::ImplItem {
57 kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id),
61 | Node::TraitItem(hir::TraitItem {
62 kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)),
66 // Use the `Span` of the `Item/ImplItem/TraitItem` as the body span,
67 // since the def span of a function does not include the body
68 (*body_id, decl.output.span(), Some(*span))
70 Node::Item(hir::Item {
71 kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id),
74 | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
75 | Node::TraitItem(hir::TraitItem {
76 kind: hir::TraitItemKind::Const(ty, Some(body_id)),
78 }) => (*body_id, ty.span, None),
79 Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
80 (*body, tcx.hir().span(*hir_id), None)
83 _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did),
86 // If we don't have a specialized span for the body, just use the
88 let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
90 tcx.infer_ctxt().enter(|infcx| {
91 let cx = Cx::new(&infcx, def, id);
92 let body = if let Some(ErrorReported) = cx.typeck_results().tainted_by_errors {
93 build::construct_error(cx, body_id)
94 } else if cx.body_owner_kind.is_fn_or_closure() {
95 // fetch the fully liberated fn signature (that is, all bound
96 // types/lifetimes replaced)
97 let fn_sig = cx.typeck_results().liberated_fn_sigs()[id];
98 let fn_def_id = tcx.hir().local_def_id(id);
100 let safety = match fn_sig.unsafety {
101 hir::Unsafety::Normal => Safety::Safe,
102 hir::Unsafety::Unsafe => Safety::FnUnsafe,
105 let body = tcx.hir().body(body_id);
106 let ty = tcx.type_of(fn_def_id);
107 let mut abi = fn_sig.abi;
108 let implicit_argument = match ty.kind() {
110 // HACK(eddyb) Avoid having RustCall on closures,
111 // as it adds unnecessary (and wrong) auto-tupling.
113 vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
115 ty::Generator(..) => {
116 let gen_ty = tcx.typeck_body(body_id).node_type(id);
118 // The resume argument may be missing, in that case we need to provide it here.
119 // It will always be `()` in this case.
120 if body.params.is_empty() {
122 ArgInfo(gen_ty, None, None, None),
123 ArgInfo(tcx.mk_unit(), None, None, None),
126 vec![ArgInfo(gen_ty, None, None, None)]
132 let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
133 let owner_id = tcx.hir().body_owner(body_id);
136 if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
137 opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
138 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
139 match fn_decl.implicit_self {
140 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
141 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
142 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
143 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
154 // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
155 // (as it's created inside the body itself, not passed in from outside).
156 let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
157 let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span));
159 tcx.type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()])
161 fn_sig.inputs()[index]
164 ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
167 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
169 let (yield_ty, return_ty) = if body.generator_kind.is_some() {
170 let gen_ty = tcx.typeck_body(body_id).node_type(id);
171 let gen_sig = match gen_ty.kind() {
172 ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
173 _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
175 (Some(gen_sig.yield_ty), gen_sig.return_ty)
177 (None, fn_sig.output())
180 let mut mir = build::construct_fn(
191 mir.yield_ty = yield_ty;
194 // Get the revealed type of this const. This is *not* the adjusted
195 // type of its body, which may be a subtype of this type. For
199 // static X: fn(&'static ()) = foo;
201 // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
202 // is not the same as the type of X. We need the type of the return
203 // place to be the type of the constant because NLL typeck will
206 let return_ty = cx.typeck_results().node_type(id);
208 build::construct_const(cx, body_id, return_ty, return_ty_span)
211 lints::check(tcx, &body);
213 // The borrow checker will replace all the regions here with its own
214 // inference variables. There's no point having non-erased regions here.
215 // The exception is `body.user_type_annotations`, which is used unmodified
216 // by borrow checking.
218 !(body.local_decls.has_free_regions()
219 || body.basic_blocks().has_free_regions()
220 || body.var_debug_info.has_free_regions()
221 || body.yield_ty.has_free_regions()),
222 "Unexpected free regions in MIR: {:?}",
230 ///////////////////////////////////////////////////////////////////////////
231 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
233 fn liberated_closure_env_ty(
235 closure_expr_id: hir::HirId,
236 body_id: hir::BodyId,
238 let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id);
240 let (closure_def_id, closure_substs) = match *closure_ty.kind() {
241 ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
242 _ => bug!("closure expr does not have closure type: {:?}", closure_ty),
245 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
246 tcx.erase_late_bound_regions(closure_env_ty)
249 #[derive(Debug, PartialEq, Eq)]
251 /// Evaluation is currently within a statement.
253 /// Examples include:
255 /// 2. `let _ = EXPR;`
256 /// 3. `let x = EXPR;`
258 /// If true, then statement discards result from evaluating
259 /// the expression (such as examples 1 and 2 above).
260 ignores_expr_result: bool,
263 /// Evaluation is currently within the tail expression of a block.
265 /// Example: `{ STMT_1; STMT_2; EXPR }`
267 /// If true, then the surrounding context of the block ignores
268 /// the result of evaluating the block's tail expression.
270 /// Example: `let _ = { STMT_1; EXPR };`
271 tail_result_is_ignored: bool,
273 /// `Span` of the tail expression.
277 /// Generic mark meaning that the block occurred as a subexpression
278 /// where the result might be used.
280 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
285 fn is_tail_expr(&self) -> bool {
287 BlockFrame::TailExpr { .. } => true,
289 BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
292 fn is_statement(&self) -> bool {
294 BlockFrame::Statement { .. } => true,
296 BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
302 struct BlockContext(Vec<BlockFrame>);
304 struct Builder<'a, 'tcx> {
311 generator_kind: Option<GeneratorKind>,
313 /// The current set of scopes, updated as we traverse;
314 /// see the `scope` module for more details.
315 scopes: scope::Scopes<'tcx>,
317 /// The block-context: each time we build the code within an thir::Block,
318 /// we push a frame here tracking whether we are building a statement or
319 /// if we are pushing the tail expression of the block. This is used to
320 /// embed information in generated temps about whether they were created
321 /// for a block tail expression or not.
323 /// It would be great if we could fold this into `self.scopes`
324 /// somehow, but right now I think that is very tightly tied to
325 /// the code generation in ways that we cannot (or should not)
326 /// start just throwing new entries onto that vector in order to
327 /// distinguish the context of EXPR1 from the context of EXPR2 in
328 /// `{ STMTS; EXPR1 } + EXPR2`.
329 block_context: BlockContext,
331 /// The current unsafe block in scope, even if it is hidden by
332 /// a `PushUnsafeBlock`.
333 unpushed_unsafe: Safety,
335 /// The number of `push_unsafe_block` levels in scope.
336 push_unsafe_count: usize,
338 /// The vector of all scopes that we have created thus far;
339 /// we track this for debuginfo later.
340 source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
341 source_scope: SourceScope,
343 /// The guard-context: each time we build the guard expression for
344 /// a match arm, we push onto this stack, and then pop when we
345 /// finish building it.
346 guard_context: Vec<GuardFrame>,
348 /// Maps `HirId`s of variable bindings to the `Local`s created for them.
349 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
350 var_indices: HirIdMap<LocalsForNode>,
351 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
352 canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
353 upvar_mutbls: Vec<Mutability>,
354 unit_temp: Option<Place<'tcx>>,
356 var_debug_info: Vec<VarDebugInfo<'tcx>>,
359 impl<'a, 'tcx> Builder<'a, 'tcx> {
360 fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
361 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
364 fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
365 self.var_indices[&id].local_id(for_guard)
373 fn push(&mut self, bf: BlockFrame) {
376 fn pop(&mut self) -> Option<BlockFrame> {
380 /// Traverses the frames on the `BlockContext`, searching for either
381 /// the first block-tail expression frame with no intervening
384 /// Notably, this skips over `SubExpr` frames; this method is
385 /// meant to be used in the context of understanding the
386 /// relationship of a temp (created within some complicated
387 /// expression) with its containing expression, and whether the
388 /// value of that *containing expression* (not the temp!) is
390 fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
391 for bf in self.0.iter().rev() {
393 BlockFrame::SubExpr => continue,
394 BlockFrame::Statement { .. } => break,
395 &BlockFrame::TailExpr { tail_result_is_ignored, span } => {
396 return Some(BlockTailInfo { tail_result_is_ignored, span });
404 /// Looks at the topmost frame on the BlockContext and reports
405 /// whether its one that would discard a block tail result.
407 /// Unlike `currently_within_ignored_tail_expression`, this does
408 /// *not* skip over `SubExpr` frames: here, we want to know
409 /// whether the block result itself is discarded.
410 fn currently_ignores_tail_results(&self) -> bool {
411 match self.0.last() {
412 // no context: conservatively assume result is read
415 // sub-expression: block result feeds into some computation
416 Some(BlockFrame::SubExpr) => false,
418 // otherwise: use accumulated is_ignored state.
420 BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. }
421 | BlockFrame::Statement { ignores_expr_result: ignored },
429 /// In the usual case, a `HirId` for an identifier maps to at most
430 /// one `Local` declaration.
433 /// The exceptional case is identifiers in a match arm's pattern
434 /// that are referenced in a guard of that match arm. For these,
435 /// we have `2` Locals.
437 /// * `for_arm_body` is the Local used in the arm body (which is
438 /// just like the `One` case above),
440 /// * `ref_for_guard` is the Local used in the arm's guard (which
441 /// is a reference to a temp that is an alias of
443 ForGuard { ref_for_guard: Local, for_arm_body: Local },
447 struct GuardFrameLocal {
451 impl GuardFrameLocal {
452 fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
453 GuardFrameLocal { id }
459 /// These are the id's of names that are bound by patterns of the
460 /// arm of *this* guard.
462 /// (Frames higher up the stack will have the id's bound in arms
463 /// further out, such as in a case like:
466 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
469 /// here, when building for FIXME.
470 locals: Vec<GuardFrameLocal>,
473 /// `ForGuard` indicates whether we are talking about:
474 /// 1. The variable for use outside of guard expressions, or
475 /// 2. The temp that holds reference to (1.), which is actually what the
476 /// guard expressions see.
477 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
484 fn local_id(&self, for_guard: ForGuard) -> Local {
485 match (self, for_guard) {
486 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard)
488 &LocalsForNode::ForGuard { ref_for_guard: local_id, .. },
489 ForGuard::RefWithinGuard,
491 | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => {
495 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => {
496 bug!("anything with one local should never be within a guard.")
503 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
506 rustc_index::newtype_index! {
507 struct ScopeId { .. }
510 ///////////////////////////////////////////////////////////////////////////
511 /// The `BlockAnd` "monad" packages up the new basic block along with a
512 /// produced value (sometimes just unit, of course). The `unpack!`
513 /// macro (and methods below) makes working with `BlockAnd` much more
516 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
517 struct BlockAnd<T>(BasicBlock, T);
519 trait BlockAndExtension {
520 fn and<T>(self, v: T) -> BlockAnd<T>;
521 fn unit(self) -> BlockAnd<()>;
524 impl BlockAndExtension for BasicBlock {
525 fn and<T>(self, v: T) -> BlockAnd<T> {
529 fn unit(self) -> BlockAnd<()> {
534 /// Update a block pointer and return the value.
535 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
536 macro_rules! unpack {
537 ($x:ident = $c:expr) => {{
538 let BlockAnd(b, v) = $c;
544 let BlockAnd(b, ()) = $c;
549 fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: LocalDefId, _abi: Abi) -> bool {
550 // Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
551 let attrs = &tcx.get_attrs(fn_def_id.to_def_id());
552 let unwind_attr = attr::find_unwind_attr(&tcx.sess, attrs);
554 // We never unwind, so it's not relevant to stop an unwind.
555 if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
559 // This is a special case: some functions have a C abi but are meant to
560 // unwind anyway. Don't stop them.
562 None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
563 Some(UnwindAttr::Allowed) => false,
564 Some(UnwindAttr::Aborts) => true,
568 ///////////////////////////////////////////////////////////////////////////
569 /// the main entry point for building MIR for a function
571 struct ArgInfo<'tcx>(
574 Option<&'tcx hir::Param<'tcx>>,
575 Option<ImplicitSelfKind>,
578 fn construct_fn<'a, 'tcx, A>(
585 return_ty_span: Span,
586 body: &'tcx hir::Body<'tcx>,
587 span_with_body: Span,
590 A: Iterator<Item = ArgInfo<'tcx>>,
592 let arguments: Vec<_> = arguments.collect();
595 let tcx_hir = tcx.hir();
596 let span = tcx_hir.span(fn_id);
598 let fn_def_id = tcx_hir.local_def_id(fn_id);
600 let mut builder = Builder::new(
602 fn_def_id.to_def_id(),
611 let call_site_scope =
612 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
614 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
615 let source_info = builder.source_info(span);
616 let call_site_s = (call_site_scope, source_info);
617 unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
618 let arg_scope_s = (arg_scope, source_info);
619 // Attribute epilogue to function's closing brace
620 let fn_end = span_with_body.shrink_to_hi();
621 let return_block = unpack!(builder.in_breakable_scope(
623 Place::return_place(),
624 Some(call_site_scope),
627 Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
628 builder.args_and_body(
630 fn_def_id.to_def_id(),
638 let source_info = builder.source_info(fn_end);
639 builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
640 let should_abort = should_abort_on_panic(tcx, fn_def_id, abi);
641 builder.build_drop_trees(should_abort);
642 builder.unschedule_return_place_drop();
646 let spread_arg = if abi == Abi::RustCall {
647 // RustCall pseudo-ABI untuples the last argument.
648 Some(Local::new(arguments.len()))
652 debug!("fn_id {:?} has attrs {:?}", fn_def_id, tcx.get_attrs(fn_def_id.to_def_id()));
654 let mut body = builder.finish();
655 body.spread_arg = spread_arg;
659 fn construct_const<'a, 'tcx>(
661 body_id: hir::BodyId,
666 let owner_id = tcx.hir().body_owner(body_id);
667 let def_id = tcx.hir().local_def_id(owner_id);
668 let span = tcx.hir().span(owner_id);
670 Builder::new(hir, def_id.to_def_id(), span, 0, Safety::Safe, const_ty, const_ty_span, None);
672 let mut block = START_BLOCK;
673 let ast_expr = &tcx.hir().body(body_id).value;
674 let expr = builder.hir.mirror(ast_expr);
675 // We don't provide a scope because we can't unwind in constants, so won't
676 // need to drop the return place.
677 unpack!(block = builder.into_expr(Place::return_place(), None, block, expr));
679 let source_info = builder.source_info(span);
680 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
682 builder.build_drop_trees(false);
687 /// Construct MIR for a item that has had errors in type checking.
689 /// This is required because we may still want to run MIR passes on an item
690 /// with type errors, but normal MIR construction can't handle that in general.
691 fn construct_error<'a, 'tcx>(hir: Cx<'a, 'tcx>, body_id: hir::BodyId) -> Body<'tcx> {
693 let owner_id = tcx.hir().body_owner(body_id);
694 let def_id = tcx.hir().local_def_id(owner_id);
695 let span = tcx.hir().span(owner_id);
696 let ty = tcx.ty_error();
697 let num_params = match hir.body_owner_kind {
698 hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len(),
699 hir::BodyOwnerKind::Closure => {
700 if tcx.hir().body(body_id).generator_kind().is_some() {
701 // Generators have an implicit `self` parameter *and* a possibly
702 // implicit resume parameter.
705 // The implicit self parameter adds another local in MIR.
706 1 + tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len()
709 hir::BodyOwnerKind::Const => 0,
710 hir::BodyOwnerKind::Static(_) => 0,
713 Builder::new(hir, def_id.to_def_id(), span, num_params, Safety::Safe, ty, span, None);
714 let source_info = builder.source_info(span);
715 // Some MIR passes will expect the number of parameters to match the
716 // function declaration.
717 for _ in 0..num_params {
718 builder.local_decls.push(LocalDecl::with_source_info(ty, source_info));
720 builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
721 let mut body = builder.finish();
722 if tcx.hir().body(body_id).generator_kind.is_some() {
723 body.yield_ty = Some(ty);
728 impl<'a, 'tcx> Builder<'a, 'tcx> {
737 generator_kind: Option<GeneratorKind>,
738 ) -> Builder<'a, 'tcx> {
739 let lint_level = LintLevel::Explicit(hir.root_lint_level);
740 let mut builder = Builder {
743 cfg: CFG { basic_blocks: IndexVec::new() },
747 scopes: scope::Scopes::new(),
748 block_context: BlockContext::new(),
749 source_scopes: IndexVec::new(),
750 source_scope: OUTERMOST_SOURCE_SCOPE,
751 guard_context: vec![],
752 push_unsafe_count: 0,
753 unpushed_unsafe: safety,
754 local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1),
755 canonical_user_type_annotations: IndexVec::new(),
756 upvar_mutbls: vec![],
757 var_indices: Default::default(),
759 var_debug_info: vec![],
762 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
764 builder.new_source_scope(span, lint_level, Some(safety)),
765 OUTERMOST_SOURCE_SCOPE
767 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
772 fn finish(self) -> Body<'tcx> {
773 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
774 if block.terminator.is_none() {
775 span_bug!(self.fn_span, "no terminator on block {:?}", index);
780 MirSource::item(self.def_id),
781 self.cfg.basic_blocks,
784 self.canonical_user_type_annotations,
794 mut block: BasicBlock,
796 arguments: &[ArgInfo<'tcx>],
797 argument_scope: region::Scope,
798 ast_body: &'tcx hir::Expr<'tcx>,
800 // Allocate locals for the function arguments
801 for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
803 SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span));
804 let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info));
806 // If this is a simple binding pattern, give debuginfo a nice name.
807 if let Some(arg) = arg_opt {
808 if let Some(ident) = arg.pat.simple_ident() {
809 self.var_debug_info.push(VarDebugInfo {
812 value: VarDebugInfoContents::Place(arg_local.into()),
818 let tcx = self.hir.tcx();
819 let tcx_hir = tcx.hir();
820 let hir_typeck_results = self.hir.typeck_results();
822 // In analyze_closure() in upvar.rs we gathered a list of upvars used by a
823 // indexed closure and we stored in a map called closure_captures in TypeckResults
824 // with the closure's DefId. Here, we run through that vec of UpvarIds for
825 // the given closure and use the necessary information to create upvar
826 // debuginfo and to fill `self.upvar_mutbls`.
827 if hir_typeck_results.closure_min_captures.get(&fn_def_id).is_some() {
828 let closure_env_arg = Local::new(1);
829 let mut closure_env_projs = vec![];
830 let mut closure_ty = self.local_decls[closure_env_arg].ty;
831 if let ty::Ref(_, ty, _) = closure_ty.kind() {
832 closure_env_projs.push(ProjectionElem::Deref);
835 let upvar_substs = match closure_ty.kind() {
836 ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
837 ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
838 _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
840 let capture_tys = upvar_substs.upvar_tys();
841 let captures_with_tys = hir_typeck_results
842 .closure_min_captures_flattened(fn_def_id)
845 self.upvar_mutbls = captures_with_tys
847 .map(|(i, (captured_place, ty))| {
848 let capture = captured_place.info.capture_kind;
849 let var_id = match captured_place.place.base {
850 HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id,
851 _ => bug!("Expected an upvar")
854 let mut mutability = Mutability::Not;
856 // FIXME(project-rfc-2229#8): Store more precise information
857 let mut name = kw::Invalid;
858 if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
859 if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
861 match hir_typeck_results
862 .extract_binding_mode(tcx.sess, pat.hir_id, pat.span)
864 Some(ty::BindByValue(hir::Mutability::Mut)) => {
865 mutability = Mutability::Mut;
867 Some(_) => mutability = Mutability::Not,
873 let mut projs = closure_env_projs.clone();
874 projs.push(ProjectionElem::Field(Field::new(i), ty));
876 ty::UpvarCapture::ByValue(_) => {}
877 ty::UpvarCapture::ByRef(..) => {
878 projs.push(ProjectionElem::Deref);
882 self.var_debug_info.push(VarDebugInfo {
884 source_info: SourceInfo::outermost(tcx_hir.span(var_id)),
885 value: VarDebugInfoContents::Place(Place {
886 local: closure_env_arg,
887 projection: tcx.intern_place_elems(&projs),
896 let mut scope = None;
897 // Bind the argument patterns
898 for (index, arg_info) in arguments.iter().enumerate() {
899 // Function arguments always get the first Local indices after the return place
900 let local = Local::new(index + 1);
901 let place = Place::from(local);
902 let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
904 // Make sure we drop (parts of) the argument even when not matched on.
906 arg_opt.as_ref().map_or(ast_body.span, |arg| arg.pat.span),
912 if let Some(arg) = arg_opt {
913 let pattern = self.hir.pattern_from_hir(&arg.pat);
914 let original_source_scope = self.source_scope;
915 let span = pattern.span;
916 self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
917 match *pattern.kind {
918 // Don't introduce extra copies for simple bindings
922 mode: BindingMode::ByValue,
926 self.local_decls[local].mutability = mutability;
927 self.local_decls[local].source_info.scope = self.source_scope;
928 self.local_decls[local].local_info = if let Some(kind) = self_binding {
929 Some(box LocalInfo::User(ClearCrossCrate::Set(
930 BindingForm::ImplicitSelf(*kind),
933 let binding_mode = ty::BindingMode::BindByValue(mutability);
934 Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
938 opt_match_place: Some((Some(place), span)),
943 self.var_indices.insert(var, LocalsForNode::One(local));
946 scope = self.declare_bindings(
950 matches::ArmHasGuard(false),
951 Some((Some(&place), span)),
953 unpack!(block = self.place_into_pattern(block, pattern, place, false));
956 self.source_scope = original_source_scope;
960 // Enter the argument pattern bindings source scope, if it exists.
961 if let Some(source_scope) = scope {
962 self.source_scope = source_scope;
965 let body = self.hir.mirror(ast_body);
967 region::Scope { id: ast_body.hir_id.local_id, data: region::ScopeData::CallSite };
968 self.into(Place::return_place(), Some(call_site), block, body)
971 fn set_correct_source_scope_for_arg(
973 arg_hir_id: hir::HirId,
974 original_source_scope: SourceScope,
977 let tcx = self.hir.tcx();
978 let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir.root_lint_level);
979 let parent_root = tcx.maybe_lint_level_root_bounded(
980 self.source_scopes[original_source_scope]
983 .assert_crate_local()
985 self.hir.root_lint_level,
987 if current_root != parent_root {
989 self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None);
993 fn get_unit_temp(&mut self) -> Place<'tcx> {
994 match self.unit_temp {
997 let ty = self.hir.unit_ty();
998 let fn_span = self.fn_span;
999 let tmp = self.temp(ty, fn_span);
1000 self.unit_temp = Some(tmp);
1007 ///////////////////////////////////////////////////////////////////////////
1008 // Builder methods are broken up into modules, depending on what kind
1009 // of thing is being lowered. Note that they use the `unpack` macro
1010 // above extensively.