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, _, _) => {
87 let gen_ty = tcx.body_tables(body_id).node_type(id);
89 // The resume argument may be missing, in that case we need to provide it here.
90 if body.params.is_empty() {
91 let resume_ty = match gen_ty.kind {
92 ty::Generator(_, substs, _) => {
93 substs.as_generator().resume_ty(def_id, tcx)
99 ArgInfo(gen_ty, None, None, None),
100 ArgInfo(resume_ty, None, None, None),
103 vec![ArgInfo(gen_ty, None, None, None)]
109 let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
110 let owner_id = tcx.hir().body_owner(body_id);
113 if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
114 opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
115 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
116 match fn_decl.implicit_self {
117 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
118 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
119 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
120 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
131 // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
132 // (as it's created inside the body itself, not passed in from outside).
133 let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
135 tcx.require_lang_item(lang_items::VaListTypeLangItem, Some(arg.span));
136 let region = tcx.mk_region(ty::ReScope(region::Scope {
137 id: body.value.hir_id.local_id,
138 data: region::ScopeData::CallSite,
141 tcx.type_of(va_list_did).subst(tcx, &[region.into()])
143 fn_sig.inputs()[index]
146 ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
149 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
151 let (yield_ty, return_ty) = if body.generator_kind.is_some() {
152 let gen_sig = match ty.kind {
153 ty::Generator(gen_def_id, gen_substs, ..) => {
154 gen_substs.as_generator().sig(gen_def_id, tcx)
156 _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
158 (Some(gen_sig.yield_ty), gen_sig.return_ty)
160 (None, fn_sig.output())
163 let mut mir = build::construct_fn(
173 mir.yield_ty = yield_ty;
176 // Get the revealed type of this const. This is *not* the adjusted
177 // type of its body, which may be a subtype of this type. For
181 // static X: fn(&'static ()) = foo;
183 // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
184 // is not the same as the type of X. We need the type of the return
185 // place to be the type of the constant because NLL typeck will
188 let return_ty = cx.tables().node_type(id);
190 build::construct_const(cx, body_id, return_ty, return_ty_span)
193 lints::check(tcx, &body, def_id);
195 let mut body = BodyAndCache::new(body);
196 body.ensure_predecessors();
201 ///////////////////////////////////////////////////////////////////////////
202 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
204 fn liberated_closure_env_ty(
206 closure_expr_id: hir::HirId,
207 body_id: hir::BodyId,
209 let closure_ty = tcx.body_tables(body_id).node_type(closure_expr_id);
211 let (closure_def_id, closure_substs) = match closure_ty.kind {
212 ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
213 _ => bug!("closure expr does not have closure type: {:?}", closure_ty),
216 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
217 tcx.liberate_late_bound_regions(closure_def_id, &closure_env_ty)
220 #[derive(Debug, PartialEq, Eq)]
222 /// Evaluation is currently within a statement.
224 /// Examples include:
226 /// 2. `let _ = EXPR;`
227 /// 3. `let x = EXPR;`
229 /// If true, then statement discards result from evaluating
230 /// the expression (such as examples 1 and 2 above).
231 ignores_expr_result: bool,
234 /// Evaluation is currently within the tail expression of a block.
236 /// Example: `{ STMT_1; STMT_2; EXPR }`
238 /// If true, then the surrounding context of the block ignores
239 /// the result of evaluating the block's tail expression.
241 /// Example: `let _ = { STMT_1; EXPR };`
242 tail_result_is_ignored: bool,
245 /// Generic mark meaning that the block occurred as a subexpression
246 /// where the result might be used.
248 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
253 fn is_tail_expr(&self) -> bool {
255 BlockFrame::TailExpr { .. } => true,
257 BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
260 fn is_statement(&self) -> bool {
262 BlockFrame::Statement { .. } => true,
264 BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
270 struct BlockContext(Vec<BlockFrame>);
272 struct Builder<'a, 'tcx> {
278 generator_kind: Option<GeneratorKind>,
280 /// The current set of scopes, updated as we traverse;
281 /// see the `scope` module for more details.
282 scopes: scope::Scopes<'tcx>,
284 /// The block-context: each time we build the code within an hair::Block,
285 /// we push a frame here tracking whether we are building a statement or
286 /// if we are pushing the tail expression of the block. This is used to
287 /// embed information in generated temps about whether they were created
288 /// for a block tail expression or not.
290 /// It would be great if we could fold this into `self.scopes`
291 /// somehow, but right now I think that is very tightly tied to
292 /// the code generation in ways that we cannot (or should not)
293 /// start just throwing new entries onto that vector in order to
294 /// distinguish the context of EXPR1 from the context of EXPR2 in
295 /// `{ STMTS; EXPR1 } + EXPR2`.
296 block_context: BlockContext,
298 /// The current unsafe block in scope, even if it is hidden by
299 /// a `PushUnsafeBlock`.
300 unpushed_unsafe: Safety,
302 /// The number of `push_unsafe_block` levels in scope.
303 push_unsafe_count: usize,
305 /// The vector of all scopes that we have created thus far;
306 /// we track this for debuginfo later.
307 source_scopes: IndexVec<SourceScope, SourceScopeData>,
308 source_scope: SourceScope,
310 /// The guard-context: each time we build the guard expression for
311 /// a match arm, we push onto this stack, and then pop when we
312 /// finish building it.
313 guard_context: Vec<GuardFrame>,
315 /// Maps `HirId`s of variable bindings to the `Local`s created for them.
316 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
317 var_indices: HirIdMap<LocalsForNode>,
318 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
319 canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
320 upvar_mutbls: Vec<Mutability>,
321 unit_temp: Option<Place<'tcx>>,
323 var_debug_info: Vec<VarDebugInfo<'tcx>>,
325 /// Cached block with the `RESUME` terminator; this is created
326 /// when first set of cleanups are built.
327 cached_resume_block: Option<BasicBlock>,
328 /// Cached block with the `RETURN` terminator.
329 cached_return_block: Option<BasicBlock>,
330 /// Cached block with the `UNREACHABLE` terminator.
331 cached_unreachable_block: Option<BasicBlock>,
334 impl<'a, 'tcx> Builder<'a, 'tcx> {
335 fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
336 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
339 fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
340 self.var_indices[&id].local_id(for_guard)
348 fn push(&mut self, bf: BlockFrame) {
351 fn pop(&mut self) -> Option<BlockFrame> {
355 /// Traverses the frames on the `BlockContext`, searching for either
356 /// the first block-tail expression frame with no intervening
359 /// Notably, this skips over `SubExpr` frames; this method is
360 /// meant to be used in the context of understanding the
361 /// relationship of a temp (created within some complicated
362 /// expression) with its containing expression, and whether the
363 /// value of that *containing expression* (not the temp!) is
365 fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
366 for bf in self.0.iter().rev() {
368 BlockFrame::SubExpr => continue,
369 BlockFrame::Statement { .. } => break,
370 &BlockFrame::TailExpr { tail_result_is_ignored } => {
371 return Some(BlockTailInfo { tail_result_is_ignored });
379 /// Looks at the topmost frame on the BlockContext and reports
380 /// whether its one that would discard a block tail result.
382 /// Unlike `currently_within_ignored_tail_expression`, this does
383 /// *not* skip over `SubExpr` frames: here, we want to know
384 /// whether the block result itself is discarded.
385 fn currently_ignores_tail_results(&self) -> bool {
386 match self.0.last() {
387 // no context: conservatively assume result is read
390 // sub-expression: block result feeds into some computation
391 Some(BlockFrame::SubExpr) => false,
393 // otherwise: use accumulated is_ignored state.
394 Some(BlockFrame::TailExpr { tail_result_is_ignored: ignored })
395 | Some(BlockFrame::Statement { ignores_expr_result: ignored }) => *ignored,
402 /// In the usual case, a `HirId` for an identifier maps to at most
403 /// one `Local` declaration.
406 /// The exceptional case is identifiers in a match arm's pattern
407 /// that are referenced in a guard of that match arm. For these,
408 /// we have `2` Locals.
410 /// * `for_arm_body` is the Local used in the arm body (which is
411 /// just like the `One` case above),
413 /// * `ref_for_guard` is the Local used in the arm's guard (which
414 /// is a reference to a temp that is an alias of
416 ForGuard { ref_for_guard: Local, for_arm_body: Local },
420 struct GuardFrameLocal {
424 impl GuardFrameLocal {
425 fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
426 GuardFrameLocal { id: id }
432 /// These are the id's of names that are bound by patterns of the
433 /// arm of *this* guard.
435 /// (Frames higher up the stack will have the id's bound in arms
436 /// further out, such as in a case like:
439 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
442 /// here, when building for FIXME.
443 locals: Vec<GuardFrameLocal>,
446 /// `ForGuard` indicates whether we are talking about:
447 /// 1. The variable for use outside of guard expressions, or
448 /// 2. The temp that holds reference to (1.), which is actually what the
449 /// guard expressions see.
450 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
457 fn local_id(&self, for_guard: ForGuard) -> Local {
458 match (self, for_guard) {
459 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard)
461 &LocalsForNode::ForGuard { ref_for_guard: local_id, .. },
462 ForGuard::RefWithinGuard,
464 | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => {
468 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => {
469 bug!("anything with one local should never be within a guard.")
476 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
479 rustc_index::newtype_index! {
480 struct ScopeId { .. }
483 ///////////////////////////////////////////////////////////////////////////
484 /// The `BlockAnd` "monad" packages up the new basic block along with a
485 /// produced value (sometimes just unit, of course). The `unpack!`
486 /// macro (and methods below) makes working with `BlockAnd` much more
489 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
490 struct BlockAnd<T>(BasicBlock, T);
492 trait BlockAndExtension {
493 fn and<T>(self, v: T) -> BlockAnd<T>;
494 fn unit(self) -> BlockAnd<()>;
497 impl BlockAndExtension for BasicBlock {
498 fn and<T>(self, v: T) -> BlockAnd<T> {
502 fn unit(self) -> BlockAnd<()> {
507 /// Update a block pointer and return the value.
508 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
509 macro_rules! unpack {
510 ($x:ident = $c:expr) => {{
511 let BlockAnd(b, v) = $c;
517 let BlockAnd(b, ()) = $c;
522 fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: DefId, _abi: Abi) -> bool {
523 // Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
524 let attrs = &tcx.get_attrs(fn_def_id);
525 let unwind_attr = attr::find_unwind_attr(Some(tcx.sess.diagnostic()), attrs);
527 // We never unwind, so it's not relevant to stop an unwind.
528 if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
532 // We cannot add landing pads, so don't add one.
533 if tcx.sess.no_landing_pads() {
537 // This is a special case: some functions have a C abi but are meant to
538 // unwind anyway. Don't stop them.
540 None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
541 Some(UnwindAttr::Allowed) => false,
542 Some(UnwindAttr::Aborts) => true,
546 ///////////////////////////////////////////////////////////////////////////
547 /// the main entry point for building MIR for a function
549 struct ArgInfo<'tcx>(
552 Option<&'tcx hir::Param<'tcx>>,
553 Option<ImplicitSelfKind>,
556 fn construct_fn<'a, 'tcx, A>(
563 return_ty_span: Span,
564 body: &'tcx hir::Body<'tcx>,
567 A: Iterator<Item = ArgInfo<'tcx>>,
569 let arguments: Vec<_> = arguments.collect();
572 let tcx_hir = tcx.hir();
573 let span = tcx_hir.span(fn_id);
575 let fn_def_id = tcx_hir.local_def_id(fn_id);
577 let mut builder = Builder::new(
587 let call_site_scope =
588 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
590 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
591 let mut block = START_BLOCK;
592 let source_info = builder.source_info(span);
593 let call_site_s = (call_site_scope, source_info);
595 block = builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
596 if should_abort_on_panic(tcx, fn_def_id, abi) {
597 builder.schedule_abort();
600 let arg_scope_s = (arg_scope, source_info);
601 // `return_block` is called when we evaluate a `return` expression, so
602 // we just use `START_BLOCK` here.
604 block = builder.in_breakable_scope(
607 Place::return_place(),
609 builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
610 builder.args_and_body(
621 // Attribute epilogue to function's closing brace
622 let fn_end = span.shrink_to_hi();
623 let source_info = builder.source_info(fn_end);
624 let return_block = builder.return_block();
625 builder.cfg.goto(block, source_info, return_block);
626 builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
627 // Attribute any unreachable codepaths to the function's closing brace
628 if let Some(unreachable_block) = builder.cached_unreachable_block {
629 builder.cfg.terminate(unreachable_block, source_info, TerminatorKind::Unreachable);
634 assert_eq!(block, builder.return_block());
636 let mut spread_arg = None;
637 if abi == Abi::RustCall {
638 // RustCall pseudo-ABI untuples the last argument.
639 spread_arg = Some(Local::new(arguments.len()));
641 debug!("fn_id {:?} has attrs {:?}", fn_def_id, tcx.get_attrs(fn_def_id));
643 let mut body = builder.finish();
644 body.spread_arg = spread_arg;
648 fn construct_const<'a, 'tcx>(
650 body_id: hir::BodyId,
655 let owner_id = tcx.hir().body_owner(body_id);
656 let span = tcx.hir().span(owner_id);
657 let mut builder = Builder::new(hir, span, 0, Safety::Safe, const_ty, const_ty_span, None);
659 let mut block = START_BLOCK;
660 let ast_expr = &tcx.hir().body(body_id).value;
661 let expr = builder.hir.mirror(ast_expr);
662 unpack!(block = builder.into_expr(&Place::return_place(), block, expr));
664 let source_info = builder.source_info(span);
665 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
667 // Constants can't `return` so a return block should not be created.
668 assert_eq!(builder.cached_return_block, None);
670 // Constants may be match expressions in which case an unreachable block may
671 // be created, so terminate it properly.
672 if let Some(unreachable_block) = builder.cached_unreachable_block {
673 builder.cfg.terminate(unreachable_block, source_info, TerminatorKind::Unreachable);
679 fn construct_error<'a, 'tcx>(hir: Cx<'a, 'tcx>, body_id: hir::BodyId) -> Body<'tcx> {
680 let owner_id = hir.tcx().hir().body_owner(body_id);
681 let span = hir.tcx().hir().span(owner_id);
682 let ty = hir.tcx().types.err;
683 let mut builder = Builder::new(hir, span, 0, Safety::Safe, ty, span, None);
684 let source_info = builder.source_info(span);
685 builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
689 impl<'a, 'tcx> Builder<'a, 'tcx> {
697 generator_kind: Option<GeneratorKind>,
698 ) -> Builder<'a, 'tcx> {
699 let lint_level = LintLevel::Explicit(hir.root_lint_level);
700 let mut builder = Builder {
702 cfg: CFG { basic_blocks: IndexVec::new() },
706 scopes: Default::default(),
707 block_context: BlockContext::new(),
708 source_scopes: IndexVec::new(),
709 source_scope: OUTERMOST_SOURCE_SCOPE,
710 guard_context: vec![],
711 push_unsafe_count: 0,
712 unpushed_unsafe: safety,
713 local_decls: IndexVec::from_elem_n(
714 LocalDecl::new_return_place(return_ty, return_span),
717 canonical_user_type_annotations: IndexVec::new(),
718 upvar_mutbls: vec![],
719 var_indices: Default::default(),
721 var_debug_info: vec![],
722 cached_resume_block: None,
723 cached_return_block: None,
724 cached_unreachable_block: None,
727 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
729 builder.new_source_scope(span, lint_level, Some(safety)),
730 OUTERMOST_SOURCE_SCOPE
732 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
737 fn finish(self) -> Body<'tcx> {
738 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
739 if block.terminator.is_none() {
740 span_bug!(self.fn_span, "no terminator on block {:?}", index);
745 self.cfg.basic_blocks,
748 self.canonical_user_type_annotations,
752 self.hir.control_flow_destroyed(),
759 mut block: BasicBlock,
761 arguments: &[ArgInfo<'tcx>],
762 argument_scope: region::Scope,
763 ast_body: &'tcx hir::Expr<'tcx>,
765 // Allocate locals for the function arguments
766 for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
767 let source_info = SourceInfo {
768 scope: OUTERMOST_SOURCE_SCOPE,
769 span: arg_opt.map_or(self.fn_span, |arg| arg.pat.span),
771 let arg_local = self.local_decls.push(LocalDecl {
772 mutability: Mutability::Mut,
774 user_ty: UserTypeProjections::none(),
777 local_info: LocalInfo::Other,
781 // If this is a simple binding pattern, give debuginfo a nice name.
782 if let Some(arg) = arg_opt {
783 if let Some(ident) = arg.pat.simple_ident() {
784 self.var_debug_info.push(VarDebugInfo {
787 place: arg_local.into(),
793 let tcx = self.hir.tcx();
794 let tcx_hir = tcx.hir();
795 let hir_tables = self.hir.tables();
797 // In analyze_closure() in upvar.rs we gathered a list of upvars used by a
798 // closure and we stored in a map called upvar_list in TypeckTables indexed
799 // with the closure's DefId. Here, we run through that vec of UpvarIds for
800 // the given closure and use the necessary information to create upvar
801 // debuginfo and to fill `self.upvar_mutbls`.
802 if let Some(upvars) = hir_tables.upvar_list.get(&fn_def_id) {
803 let closure_env_arg = Local::new(1);
804 let mut closure_env_projs = vec![];
805 let mut closure_ty = self.local_decls[closure_env_arg].ty;
806 if let ty::Ref(_, ty, _) = closure_ty.kind {
807 closure_env_projs.push(ProjectionElem::Deref);
810 let (def_id, upvar_substs) = match closure_ty.kind {
811 ty::Closure(def_id, substs) => (def_id, ty::UpvarSubsts::Closure(substs)),
812 ty::Generator(def_id, substs, _) => (def_id, ty::UpvarSubsts::Generator(substs)),
813 _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
815 let upvar_tys = upvar_substs.upvar_tys(def_id, tcx);
816 let upvars_with_tys = upvars.iter().zip(upvar_tys);
817 self.upvar_mutbls = upvars_with_tys
819 .map(|(i, ((&var_id, &upvar_id), ty))| {
820 let capture = hir_tables.upvar_capture(upvar_id);
822 let mut mutability = Mutability::Not;
823 let mut name = kw::Invalid;
824 if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
825 if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
827 match hir_tables.extract_binding_mode(tcx.sess, pat.hir_id, pat.span) {
828 Some(ty::BindByValue(hir::Mutability::Mut)) => {
829 mutability = Mutability::Mut;
831 Some(_) => mutability = Mutability::Not,
837 let mut projs = closure_env_projs.clone();
838 projs.push(ProjectionElem::Field(Field::new(i), ty));
840 ty::UpvarCapture::ByValue => {}
841 ty::UpvarCapture::ByRef(..) => {
842 projs.push(ProjectionElem::Deref);
846 self.var_debug_info.push(VarDebugInfo {
848 source_info: SourceInfo {
849 scope: OUTERMOST_SOURCE_SCOPE,
850 span: tcx_hir.span(var_id),
853 local: closure_env_arg.into(),
854 projection: tcx.intern_place_elems(&projs),
863 let mut scope = None;
864 // Bind the argument patterns
865 for (index, arg_info) in arguments.iter().enumerate() {
866 // Function arguments always get the first Local indices after the return place
867 let local = Local::new(index + 1);
868 let place = Place::from(local);
869 let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
871 // Make sure we drop (parts of) the argument even when not matched on.
873 arg_opt.as_ref().map_or(ast_body.span, |arg| arg.pat.span),
879 if let Some(arg) = arg_opt {
880 let pattern = self.hir.pattern_from_hir(&arg.pat);
881 let original_source_scope = self.source_scope;
882 let span = pattern.span;
883 self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
884 match *pattern.kind {
885 // Don't introduce extra copies for simple bindings
889 mode: BindingMode::ByValue,
893 self.local_decls[local].mutability = mutability;
894 self.local_decls[local].source_info.scope = self.source_scope;
895 self.local_decls[local].local_info = if let Some(kind) = self_binding {
896 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind)))
898 let binding_mode = ty::BindingMode::BindByValue(mutability.into());
899 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
903 opt_match_place: Some((Some(place), span)),
908 self.var_indices.insert(var, LocalsForNode::One(local));
911 scope = self.declare_bindings(
915 matches::ArmHasGuard(false),
916 Some((Some(&place), span)),
918 unpack!(block = self.place_into_pattern(block, pattern, &place, false));
921 self.source_scope = original_source_scope;
925 // Enter the argument pattern bindings source scope, if it exists.
926 if let Some(source_scope) = scope {
927 self.source_scope = source_scope;
930 let body = self.hir.mirror(ast_body);
931 self.into(&Place::return_place(), block, body)
934 fn set_correct_source_scope_for_arg(
936 arg_hir_id: hir::HirId,
937 original_source_scope: SourceScope,
940 let tcx = self.hir.tcx();
941 let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir.root_lint_level);
942 let parent_root = tcx.maybe_lint_level_root_bounded(
943 self.source_scopes[original_source_scope]
946 .assert_crate_local()
948 self.hir.root_lint_level,
950 if current_root != parent_root {
952 self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None);
956 fn get_unit_temp(&mut self) -> Place<'tcx> {
957 match self.unit_temp {
960 let ty = self.hir.unit_ty();
961 let fn_span = self.fn_span;
962 let tmp = self.temp(ty, fn_span);
963 self.unit_temp = Some(tmp);
969 fn return_block(&mut self) -> BasicBlock {
970 match self.cached_return_block {
973 let rb = self.cfg.start_new_block();
974 self.cached_return_block = Some(rb);
981 ///////////////////////////////////////////////////////////////////////////
982 // Builder methods are broken up into modules, depending on what kind
983 // of thing is being lowered. Note that they use the `unpack` macro
984 // above extensively.