2 use crate::build::scope::DropKind;
3 use crate::hair::cx::Cx;
4 use crate::hair::{BindingMode, LintLevel, PatKind};
5 use rustc::middle::lang_items;
6 use rustc::middle::region;
8 use rustc::ty::subst::Subst;
9 use rustc::ty::{self, Ty, TyCtxt};
10 use rustc_attr::{self as attr, UnwindAttr};
12 use rustc_hir::def_id::DefId;
13 use rustc_hir::{GeneratorKind, HirIdMap, Node};
14 use rustc_index::vec::{Idx, IndexVec};
15 use rustc_span::symbol::kw;
17 use rustc_target::spec::abi::Abi;
18 use rustc_target::spec::PanicStrategy;
23 crate fn mir_built(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::steal::Steal<BodyAndCache<'_>> {
24 tcx.alloc_steal_mir(mir_build(tcx, def_id))
27 /// Construct the MIR for a given `DefId`.
28 fn mir_build(tcx: TyCtxt<'_>, def_id: DefId) -> BodyAndCache<'_> {
29 let id = tcx.hir().as_local_hir_id(def_id).unwrap();
31 // Figure out what primary body this item has.
32 let (body_id, return_ty_span) = match tcx.hir().get(id) {
33 Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) => {
34 (*body_id, decl.output.span())
36 Node::Item(hir::Item {
37 kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
40 | Node::ImplItem(hir::ImplItem {
41 kind: hir::ImplItemKind::Method(hir::FnSig { decl, .. }, body_id),
44 | Node::TraitItem(hir::TraitItem {
46 hir::TraitItemKind::Method(hir::FnSig { decl, .. }, hir::TraitMethod::Provided(body_id)),
48 }) => (*body_id, decl.output.span()),
49 Node::Item(hir::Item { kind: hir::ItemKind::Static(ty, _, body_id), .. })
50 | Node::Item(hir::Item { kind: hir::ItemKind::Const(ty, body_id), .. })
51 | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
52 | Node::TraitItem(hir::TraitItem {
53 kind: hir::TraitItemKind::Const(ty, Some(body_id)),
55 }) => (*body_id, ty.span),
56 Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => (*body, tcx.hir().span(*hir_id)),
58 _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def_id),
61 tcx.infer_ctxt().enter(|infcx| {
62 let cx = Cx::new(&infcx, id);
63 let body = if cx.tables().tainted_by_errors {
64 build::construct_error(cx, body_id)
65 } else if cx.body_owner_kind.is_fn_or_closure() {
66 // fetch the fully liberated fn signature (that is, all bound
67 // types/lifetimes replaced)
68 let fn_sig = cx.tables().liberated_fn_sigs()[id];
69 let fn_def_id = tcx.hir().local_def_id(id);
71 let safety = match fn_sig.unsafety {
72 hir::Unsafety::Normal => Safety::Safe,
73 hir::Unsafety::Unsafe => Safety::FnUnsafe,
76 let body = tcx.hir().body(body_id);
77 let ty = tcx.type_of(fn_def_id);
78 let mut abi = fn_sig.abi;
79 let implicit_argument = match ty.kind {
81 // HACK(eddyb) Avoid having RustCall on closures,
82 // as it adds unnecessary (and wrong) auto-tupling.
84 vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
86 ty::Generator(def_id, substs, _) => {
87 let gen_ty = tcx.body_tables(body_id).node_type(id);
88 let resume_ty = substs.as_generator().resume_ty(def_id, tcx);
90 // The resume argument may be missing, in that case we need to provide it here.
91 if body.params.is_empty() {
93 ArgInfo(gen_ty, None, None, None),
94 ArgInfo(resume_ty, None, None, None),
97 vec![ArgInfo(gen_ty, None, None, None)]
103 let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
104 let owner_id = tcx.hir().body_owner(body_id);
107 if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
108 opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
109 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
110 match fn_decl.implicit_self {
111 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
112 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
113 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
114 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
125 // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
126 // (as it's created inside the body itself, not passed in from outside).
127 let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
129 tcx.require_lang_item(lang_items::VaListTypeLangItem, Some(arg.span));
130 let region = tcx.mk_region(ty::ReScope(region::Scope {
131 id: body.value.hir_id.local_id,
132 data: region::ScopeData::CallSite,
135 tcx.type_of(va_list_did).subst(tcx, &[region.into()])
137 fn_sig.inputs()[index]
140 ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
143 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
145 let (yield_ty, return_ty) = if body.generator_kind.is_some() {
146 let gen_sig = match ty.kind {
147 ty::Generator(gen_def_id, gen_substs, ..) => {
148 gen_substs.as_generator().sig(gen_def_id, tcx)
150 _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
152 (Some(gen_sig.yield_ty), gen_sig.return_ty)
154 (None, fn_sig.output())
157 let mut mir = build::construct_fn(
167 mir.yield_ty = yield_ty;
170 // Get the revealed type of this const. This is *not* the adjusted
171 // type of its body, which may be a subtype of this type. For
175 // static X: fn(&'static ()) = foo;
177 // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
178 // is not the same as the type of X. We need the type of the return
179 // place to be the type of the constant because NLL typeck will
182 let return_ty = cx.tables().node_type(id);
184 build::construct_const(cx, body_id, return_ty, return_ty_span)
187 lints::check(tcx, &body, def_id);
189 let mut body = BodyAndCache::new(body);
190 body.ensure_predecessors();
195 ///////////////////////////////////////////////////////////////////////////
196 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
198 fn liberated_closure_env_ty(
200 closure_expr_id: hir::HirId,
201 body_id: hir::BodyId,
203 let closure_ty = tcx.body_tables(body_id).node_type(closure_expr_id);
205 let (closure_def_id, closure_substs) = match closure_ty.kind {
206 ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
207 _ => bug!("closure expr does not have closure type: {:?}", closure_ty),
210 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
211 tcx.liberate_late_bound_regions(closure_def_id, &closure_env_ty)
214 #[derive(Debug, PartialEq, Eq)]
216 /// Evaluation is currently within a statement.
218 /// Examples include:
220 /// 2. `let _ = EXPR;`
221 /// 3. `let x = EXPR;`
223 /// If true, then statement discards result from evaluating
224 /// the expression (such as examples 1 and 2 above).
225 ignores_expr_result: bool,
228 /// Evaluation is currently within the tail expression of a block.
230 /// Example: `{ STMT_1; STMT_2; EXPR }`
232 /// If true, then the surrounding context of the block ignores
233 /// the result of evaluating the block's tail expression.
235 /// Example: `let _ = { STMT_1; EXPR };`
236 tail_result_is_ignored: bool,
239 /// Generic mark meaning that the block occurred as a subexpression
240 /// where the result might be used.
242 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
247 fn is_tail_expr(&self) -> bool {
249 BlockFrame::TailExpr { .. } => true,
251 BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
254 fn is_statement(&self) -> bool {
256 BlockFrame::Statement { .. } => true,
258 BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
264 struct BlockContext(Vec<BlockFrame>);
266 struct Builder<'a, 'tcx> {
272 generator_kind: Option<GeneratorKind>,
274 /// The current set of scopes, updated as we traverse;
275 /// see the `scope` module for more details.
276 scopes: scope::Scopes<'tcx>,
278 /// The block-context: each time we build the code within an hair::Block,
279 /// we push a frame here tracking whether we are building a statement or
280 /// if we are pushing the tail expression of the block. This is used to
281 /// embed information in generated temps about whether they were created
282 /// for a block tail expression or not.
284 /// It would be great if we could fold this into `self.scopes`
285 /// somehow, but right now I think that is very tightly tied to
286 /// the code generation in ways that we cannot (or should not)
287 /// start just throwing new entries onto that vector in order to
288 /// distinguish the context of EXPR1 from the context of EXPR2 in
289 /// `{ STMTS; EXPR1 } + EXPR2`.
290 block_context: BlockContext,
292 /// The current unsafe block in scope, even if it is hidden by
293 /// a `PushUnsafeBlock`.
294 unpushed_unsafe: Safety,
296 /// The number of `push_unsafe_block` levels in scope.
297 push_unsafe_count: usize,
299 /// The vector of all scopes that we have created thus far;
300 /// we track this for debuginfo later.
301 source_scopes: IndexVec<SourceScope, SourceScopeData>,
302 source_scope: SourceScope,
304 /// The guard-context: each time we build the guard expression for
305 /// a match arm, we push onto this stack, and then pop when we
306 /// finish building it.
307 guard_context: Vec<GuardFrame>,
309 /// Maps `HirId`s of variable bindings to the `Local`s created for them.
310 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
311 var_indices: HirIdMap<LocalsForNode>,
312 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
313 canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
314 upvar_mutbls: Vec<Mutability>,
315 unit_temp: Option<Place<'tcx>>,
317 var_debug_info: Vec<VarDebugInfo<'tcx>>,
319 /// Cached block with the `RESUME` terminator; this is created
320 /// when first set of cleanups are built.
321 cached_resume_block: Option<BasicBlock>,
322 /// Cached block with the `RETURN` terminator.
323 cached_return_block: Option<BasicBlock>,
324 /// Cached block with the `UNREACHABLE` terminator.
325 cached_unreachable_block: Option<BasicBlock>,
328 impl<'a, 'tcx> Builder<'a, 'tcx> {
329 fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
330 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
333 fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
334 self.var_indices[&id].local_id(for_guard)
342 fn push(&mut self, bf: BlockFrame) {
345 fn pop(&mut self) -> Option<BlockFrame> {
349 /// Traverses the frames on the `BlockContext`, searching for either
350 /// the first block-tail expression frame with no intervening
353 /// Notably, this skips over `SubExpr` frames; this method is
354 /// meant to be used in the context of understanding the
355 /// relationship of a temp (created within some complicated
356 /// expression) with its containing expression, and whether the
357 /// value of that *containing expression* (not the temp!) is
359 fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
360 for bf in self.0.iter().rev() {
362 BlockFrame::SubExpr => continue,
363 BlockFrame::Statement { .. } => break,
364 &BlockFrame::TailExpr { tail_result_is_ignored } => {
365 return Some(BlockTailInfo { tail_result_is_ignored });
373 /// Looks at the topmost frame on the BlockContext and reports
374 /// whether its one that would discard a block tail result.
376 /// Unlike `currently_within_ignored_tail_expression`, this does
377 /// *not* skip over `SubExpr` frames: here, we want to know
378 /// whether the block result itself is discarded.
379 fn currently_ignores_tail_results(&self) -> bool {
380 match self.0.last() {
381 // no context: conservatively assume result is read
384 // sub-expression: block result feeds into some computation
385 Some(BlockFrame::SubExpr) => false,
387 // otherwise: use accumulated is_ignored state.
388 Some(BlockFrame::TailExpr { tail_result_is_ignored: ignored })
389 | Some(BlockFrame::Statement { ignores_expr_result: ignored }) => *ignored,
396 /// In the usual case, a `HirId` for an identifier maps to at most
397 /// one `Local` declaration.
400 /// The exceptional case is identifiers in a match arm's pattern
401 /// that are referenced in a guard of that match arm. For these,
402 /// we have `2` Locals.
404 /// * `for_arm_body` is the Local used in the arm body (which is
405 /// just like the `One` case above),
407 /// * `ref_for_guard` is the Local used in the arm's guard (which
408 /// is a reference to a temp that is an alias of
410 ForGuard { ref_for_guard: Local, for_arm_body: Local },
414 struct GuardFrameLocal {
418 impl GuardFrameLocal {
419 fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
420 GuardFrameLocal { id: id }
426 /// These are the id's of names that are bound by patterns of the
427 /// arm of *this* guard.
429 /// (Frames higher up the stack will have the id's bound in arms
430 /// further out, such as in a case like:
433 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
436 /// here, when building for FIXME.
437 locals: Vec<GuardFrameLocal>,
440 /// `ForGuard` indicates whether we are talking about:
441 /// 1. The variable for use outside of guard expressions, or
442 /// 2. The temp that holds reference to (1.), which is actually what the
443 /// guard expressions see.
444 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
451 fn local_id(&self, for_guard: ForGuard) -> Local {
452 match (self, for_guard) {
453 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard)
455 &LocalsForNode::ForGuard { ref_for_guard: local_id, .. },
456 ForGuard::RefWithinGuard,
458 | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => {
462 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => {
463 bug!("anything with one local should never be within a guard.")
470 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
473 rustc_index::newtype_index! {
474 struct ScopeId { .. }
477 ///////////////////////////////////////////////////////////////////////////
478 /// The `BlockAnd` "monad" packages up the new basic block along with a
479 /// produced value (sometimes just unit, of course). The `unpack!`
480 /// macro (and methods below) makes working with `BlockAnd` much more
483 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
484 struct BlockAnd<T>(BasicBlock, T);
486 trait BlockAndExtension {
487 fn and<T>(self, v: T) -> BlockAnd<T>;
488 fn unit(self) -> BlockAnd<()>;
491 impl BlockAndExtension for BasicBlock {
492 fn and<T>(self, v: T) -> BlockAnd<T> {
496 fn unit(self) -> BlockAnd<()> {
501 /// Update a block pointer and return the value.
502 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
503 macro_rules! unpack {
504 ($x:ident = $c:expr) => {{
505 let BlockAnd(b, v) = $c;
511 let BlockAnd(b, ()) = $c;
516 fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: DefId, _abi: Abi) -> bool {
517 // Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
518 let attrs = &tcx.get_attrs(fn_def_id);
519 let unwind_attr = attr::find_unwind_attr(Some(tcx.sess.diagnostic()), attrs);
521 // We never unwind, so it's not relevant to stop an unwind.
522 if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
526 // We cannot add landing pads, so don't add one.
527 if tcx.sess.no_landing_pads() {
531 // This is a special case: some functions have a C abi but are meant to
532 // unwind anyway. Don't stop them.
534 None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
535 Some(UnwindAttr::Allowed) => false,
536 Some(UnwindAttr::Aborts) => true,
540 ///////////////////////////////////////////////////////////////////////////
541 /// the main entry point for building MIR for a function
543 struct ArgInfo<'tcx>(
546 Option<&'tcx hir::Param<'tcx>>,
547 Option<ImplicitSelfKind>,
550 fn construct_fn<'a, 'tcx, A>(
557 return_ty_span: Span,
558 body: &'tcx hir::Body<'tcx>,
561 A: Iterator<Item = ArgInfo<'tcx>>,
563 let arguments: Vec<_> = arguments.collect();
566 let tcx_hir = tcx.hir();
567 let span = tcx_hir.span(fn_id);
569 let fn_def_id = tcx_hir.local_def_id(fn_id);
571 let mut builder = Builder::new(
581 let call_site_scope =
582 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
584 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
585 let mut block = START_BLOCK;
586 let source_info = builder.source_info(span);
587 let call_site_s = (call_site_scope, source_info);
589 block = builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
590 if should_abort_on_panic(tcx, fn_def_id, abi) {
591 builder.schedule_abort();
594 let arg_scope_s = (arg_scope, source_info);
595 // `return_block` is called when we evaluate a `return` expression, so
596 // we just use `START_BLOCK` here.
598 block = builder.in_breakable_scope(
601 Place::return_place(),
603 builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
604 builder.args_and_body(
615 // Attribute epilogue to function's closing brace
616 let fn_end = span.shrink_to_hi();
617 let source_info = builder.source_info(fn_end);
618 let return_block = builder.return_block();
619 builder.cfg.goto(block, source_info, return_block);
620 builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
621 // Attribute any unreachable codepaths to the function's closing brace
622 if let Some(unreachable_block) = builder.cached_unreachable_block {
623 builder.cfg.terminate(unreachable_block, source_info, TerminatorKind::Unreachable);
628 assert_eq!(block, builder.return_block());
630 let mut spread_arg = None;
631 if abi == Abi::RustCall {
632 // RustCall pseudo-ABI untuples the last argument.
633 spread_arg = Some(Local::new(arguments.len()));
635 debug!("fn_id {:?} has attrs {:?}", fn_def_id, tcx.get_attrs(fn_def_id));
637 let mut body = builder.finish();
638 body.spread_arg = spread_arg;
642 fn construct_const<'a, 'tcx>(
644 body_id: hir::BodyId,
649 let owner_id = tcx.hir().body_owner(body_id);
650 let span = tcx.hir().span(owner_id);
651 let mut builder = Builder::new(hir, span, 0, Safety::Safe, const_ty, const_ty_span, None);
653 let mut block = START_BLOCK;
654 let ast_expr = &tcx.hir().body(body_id).value;
655 let expr = builder.hir.mirror(ast_expr);
656 unpack!(block = builder.into_expr(&Place::return_place(), block, expr));
658 let source_info = builder.source_info(span);
659 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
661 // Constants can't `return` so a return block should not be created.
662 assert_eq!(builder.cached_return_block, None);
664 // Constants may be match expressions in which case an unreachable block may
665 // be created, so terminate it properly.
666 if let Some(unreachable_block) = builder.cached_unreachable_block {
667 builder.cfg.terminate(unreachable_block, source_info, TerminatorKind::Unreachable);
673 fn construct_error<'a, 'tcx>(hir: Cx<'a, 'tcx>, body_id: hir::BodyId) -> Body<'tcx> {
674 let owner_id = hir.tcx().hir().body_owner(body_id);
675 let span = hir.tcx().hir().span(owner_id);
676 let ty = hir.tcx().types.err;
677 let mut builder = Builder::new(hir, span, 0, Safety::Safe, ty, span, None);
678 let source_info = builder.source_info(span);
679 builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
683 impl<'a, 'tcx> Builder<'a, 'tcx> {
691 generator_kind: Option<GeneratorKind>,
692 ) -> Builder<'a, 'tcx> {
693 let lint_level = LintLevel::Explicit(hir.root_lint_level);
694 let mut builder = Builder {
696 cfg: CFG { basic_blocks: IndexVec::new() },
700 scopes: Default::default(),
701 block_context: BlockContext::new(),
702 source_scopes: IndexVec::new(),
703 source_scope: OUTERMOST_SOURCE_SCOPE,
704 guard_context: vec![],
705 push_unsafe_count: 0,
706 unpushed_unsafe: safety,
707 local_decls: IndexVec::from_elem_n(
708 LocalDecl::new_return_place(return_ty, return_span),
711 canonical_user_type_annotations: IndexVec::new(),
712 upvar_mutbls: vec![],
713 var_indices: Default::default(),
715 var_debug_info: vec![],
716 cached_resume_block: None,
717 cached_return_block: None,
718 cached_unreachable_block: None,
721 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
723 builder.new_source_scope(span, lint_level, Some(safety)),
724 OUTERMOST_SOURCE_SCOPE
726 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
731 fn finish(self) -> Body<'tcx> {
732 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
733 if block.terminator.is_none() {
734 span_bug!(self.fn_span, "no terminator on block {:?}", index);
739 self.cfg.basic_blocks,
742 self.canonical_user_type_annotations,
746 self.hir.control_flow_destroyed(),
753 mut block: BasicBlock,
755 arguments: &[ArgInfo<'tcx>],
756 argument_scope: region::Scope,
757 ast_body: &'tcx hir::Expr<'tcx>,
759 // Allocate locals for the function arguments
760 for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
761 let source_info = SourceInfo {
762 scope: OUTERMOST_SOURCE_SCOPE,
763 span: arg_opt.map_or(self.fn_span, |arg| arg.pat.span),
765 let arg_local = self.local_decls.push(LocalDecl {
766 mutability: Mutability::Mut,
768 user_ty: UserTypeProjections::none(),
771 local_info: LocalInfo::Other,
775 // If this is a simple binding pattern, give debuginfo a nice name.
776 if let Some(arg) = arg_opt {
777 if let Some(ident) = arg.pat.simple_ident() {
778 self.var_debug_info.push(VarDebugInfo {
781 place: arg_local.into(),
787 let tcx = self.hir.tcx();
788 let tcx_hir = tcx.hir();
789 let hir_tables = self.hir.tables();
791 // In analyze_closure() in upvar.rs we gathered a list of upvars used by a
792 // closure and we stored in a map called upvar_list in TypeckTables indexed
793 // with the closure's DefId. Here, we run through that vec of UpvarIds for
794 // the given closure and use the necessary information to create upvar
795 // debuginfo and to fill `self.upvar_mutbls`.
796 if let Some(upvars) = hir_tables.upvar_list.get(&fn_def_id) {
797 let closure_env_arg = Local::new(1);
798 let mut closure_env_projs = vec![];
799 let mut closure_ty = self.local_decls[closure_env_arg].ty;
800 if let ty::Ref(_, ty, _) = closure_ty.kind {
801 closure_env_projs.push(ProjectionElem::Deref);
804 let (def_id, upvar_substs) = match closure_ty.kind {
805 ty::Closure(def_id, substs) => (def_id, ty::UpvarSubsts::Closure(substs)),
806 ty::Generator(def_id, substs, _) => (def_id, ty::UpvarSubsts::Generator(substs)),
807 _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
809 let upvar_tys = upvar_substs.upvar_tys(def_id, tcx);
810 let upvars_with_tys = upvars.iter().zip(upvar_tys);
811 self.upvar_mutbls = upvars_with_tys
813 .map(|(i, ((&var_id, &upvar_id), ty))| {
814 let capture = hir_tables.upvar_capture(upvar_id);
816 let mut mutability = Mutability::Not;
817 let mut name = kw::Invalid;
818 if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
819 if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
821 match hir_tables.extract_binding_mode(tcx.sess, pat.hir_id, pat.span) {
822 Some(ty::BindByValue(hir::Mutability::Mut)) => {
823 mutability = Mutability::Mut;
825 Some(_) => mutability = Mutability::Not,
831 let mut projs = closure_env_projs.clone();
832 projs.push(ProjectionElem::Field(Field::new(i), ty));
834 ty::UpvarCapture::ByValue => {}
835 ty::UpvarCapture::ByRef(..) => {
836 projs.push(ProjectionElem::Deref);
840 self.var_debug_info.push(VarDebugInfo {
842 source_info: SourceInfo {
843 scope: OUTERMOST_SOURCE_SCOPE,
844 span: tcx_hir.span(var_id),
847 local: closure_env_arg.into(),
848 projection: tcx.intern_place_elems(&projs),
857 let mut scope = None;
858 // Bind the argument patterns
859 for (index, arg_info) in arguments.iter().enumerate() {
860 // Function arguments always get the first Local indices after the return place
861 let local = Local::new(index + 1);
862 let place = Place::from(local);
863 let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
865 // Make sure we drop (parts of) the argument even when not matched on.
867 arg_opt.as_ref().map_or(ast_body.span, |arg| arg.pat.span),
873 if let Some(arg) = arg_opt {
874 let pattern = self.hir.pattern_from_hir(&arg.pat);
875 let original_source_scope = self.source_scope;
876 let span = pattern.span;
877 self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
878 match *pattern.kind {
879 // Don't introduce extra copies for simple bindings
883 mode: BindingMode::ByValue,
887 self.local_decls[local].mutability = mutability;
888 self.local_decls[local].source_info.scope = self.source_scope;
889 self.local_decls[local].local_info = if let Some(kind) = self_binding {
890 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind)))
892 let binding_mode = ty::BindingMode::BindByValue(mutability.into());
893 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
897 opt_match_place: Some((Some(place), span)),
902 self.var_indices.insert(var, LocalsForNode::One(local));
905 scope = self.declare_bindings(
909 matches::ArmHasGuard(false),
910 Some((Some(&place), span)),
912 unpack!(block = self.place_into_pattern(block, pattern, &place, false));
915 self.source_scope = original_source_scope;
919 // Enter the argument pattern bindings source scope, if it exists.
920 if let Some(source_scope) = scope {
921 self.source_scope = source_scope;
924 let body = self.hir.mirror(ast_body);
925 self.into(&Place::return_place(), block, body)
928 fn set_correct_source_scope_for_arg(
930 arg_hir_id: hir::HirId,
931 original_source_scope: SourceScope,
934 let tcx = self.hir.tcx();
935 let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir.root_lint_level);
936 let parent_root = tcx.maybe_lint_level_root_bounded(
937 self.source_scopes[original_source_scope]
940 .assert_crate_local()
942 self.hir.root_lint_level,
944 if current_root != parent_root {
946 self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None);
950 fn get_unit_temp(&mut self) -> Place<'tcx> {
951 match self.unit_temp {
954 let ty = self.hir.unit_ty();
955 let fn_span = self.fn_span;
956 let tmp = self.temp(ty, fn_span);
957 self.unit_temp = Some(tmp);
963 fn return_block(&mut self) -> BasicBlock {
964 match self.cached_return_block {
967 let rb = self.cfg.start_new_block();
968 self.cached_return_block = Some(rb);
975 ///////////////////////////////////////////////////////////////////////////
976 // Builder methods are broken up into modules, depending on what kind
977 // of thing is being lowered. Note that they use the `unpack` macro
978 // above extensively.