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::middle::region;
14 use rustc_middle::mir::*;
15 use rustc_middle::ty::subst::Subst;
16 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
17 use rustc_span::symbol::kw;
19 use rustc_target::spec::abi::Abi;
20 use rustc_target::spec::PanicStrategy;
24 crate fn mir_built<'tcx>(
26 def: ty::WithOptConstParam<LocalDefId>,
27 ) -> &'tcx rustc_data_structures::steal::Steal<Body<'tcx>> {
28 if let Some(def) = def.try_upgrade(tcx) {
29 return tcx.mir_built(def);
32 let mut body = mir_build(tcx, def);
33 if def.const_param_did.is_some() {
34 assert!(matches!(body.source.instance, ty::InstanceDef::Item(_)));
35 body.source = MirSource::from_instance(ty::InstanceDef::Item(def.to_global()));
38 tcx.alloc_steal_mir(body)
41 /// Construct the MIR for a given `DefId`.
42 fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
43 let id = tcx.hir().local_def_id_to_hir_id(def.did);
45 // Figure out what primary body this item has.
46 let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
47 Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) => {
48 (*body_id, decl.output.span(), None)
50 Node::Item(hir::Item {
51 kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
55 | Node::ImplItem(hir::ImplItem {
56 kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id),
60 | Node::TraitItem(hir::TraitItem {
61 kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)),
65 // Use the `Span` of the `Item/ImplItem/TraitItem` as the body span,
66 // since the def span of a function does not include the body
67 (*body_id, decl.output.span(), Some(*span))
69 Node::Item(hir::Item {
70 kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id),
73 | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
74 | Node::TraitItem(hir::TraitItem {
75 kind: hir::TraitItemKind::Const(ty, Some(body_id)),
77 }) => (*body_id, ty.span, None),
78 Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => (*body, tcx.hir().span(*hir_id), None),
80 _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did),
83 // If we don't have a specialized span for the body, just use the
85 let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
87 tcx.infer_ctxt().enter(|infcx| {
88 let cx = Cx::new(&infcx, def, id);
89 let body = if let Some(ErrorReported) = cx.typeck_results().tainted_by_errors {
90 build::construct_error(cx, body_id)
91 } else if cx.body_owner_kind.is_fn_or_closure() {
92 // fetch the fully liberated fn signature (that is, all bound
93 // types/lifetimes replaced)
94 let fn_sig = cx.typeck_results().liberated_fn_sigs()[id];
95 let fn_def_id = tcx.hir().local_def_id(id);
97 let safety = match fn_sig.unsafety {
98 hir::Unsafety::Normal => Safety::Safe,
99 hir::Unsafety::Unsafe => Safety::FnUnsafe,
102 let body = tcx.hir().body(body_id);
103 let ty = tcx.type_of(fn_def_id);
104 let mut abi = fn_sig.abi;
105 let implicit_argument = match ty.kind() {
107 // HACK(eddyb) Avoid having RustCall on closures,
108 // as it adds unnecessary (and wrong) auto-tupling.
110 vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
112 ty::Generator(..) => {
113 let gen_ty = tcx.typeck_body(body_id).node_type(id);
115 // The resume argument may be missing, in that case we need to provide it here.
116 // It will always be `()` in this case.
117 if body.params.is_empty() {
119 ArgInfo(gen_ty, None, None, None),
120 ArgInfo(tcx.mk_unit(), None, None, None),
123 vec![ArgInfo(gen_ty, None, None, None)]
129 let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
130 let owner_id = tcx.hir().body_owner(body_id);
133 if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
134 opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
135 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
136 match fn_decl.implicit_self {
137 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
138 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
139 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
140 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
151 // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
152 // (as it's created inside the body itself, not passed in from outside).
153 let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
154 let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span));
156 tcx.type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()])
158 fn_sig.inputs()[index]
161 ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
164 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
166 let (yield_ty, return_ty) = if body.generator_kind.is_some() {
167 let gen_ty = tcx.typeck_body(body_id).node_type(id);
168 let gen_sig = match gen_ty.kind() {
169 ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
170 _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
172 (Some(gen_sig.yield_ty), gen_sig.return_ty)
174 (None, fn_sig.output())
177 let mut mir = build::construct_fn(
188 mir.yield_ty = yield_ty;
191 // Get the revealed type of this const. This is *not* the adjusted
192 // type of its body, which may be a subtype of this type. For
196 // static X: fn(&'static ()) = foo;
198 // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
199 // is not the same as the type of X. We need the type of the return
200 // place to be the type of the constant because NLL typeck will
203 let return_ty = cx.typeck_results().node_type(id);
205 build::construct_const(cx, body_id, return_ty, return_ty_span)
208 lints::check(tcx, &body);
210 // The borrow checker will replace all the regions here with its own
211 // inference variables. There's no point having non-erased regions here.
212 // The exception is `body.user_type_annotations`, which is used unmodified
213 // by borrow checking.
215 !(body.local_decls.has_free_regions()
216 || body.basic_blocks().has_free_regions()
217 || body.var_debug_info.has_free_regions()
218 || body.yield_ty.has_free_regions()),
219 "Unexpected free regions in MIR: {:?}",
227 ///////////////////////////////////////////////////////////////////////////
228 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
230 fn liberated_closure_env_ty(
232 closure_expr_id: hir::HirId,
233 body_id: hir::BodyId,
235 let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id);
237 let (closure_def_id, closure_substs) = match *closure_ty.kind() {
238 ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
239 _ => bug!("closure expr does not have closure type: {:?}", closure_ty),
242 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
243 tcx.erase_late_bound_regions(closure_env_ty)
246 #[derive(Debug, PartialEq, Eq)]
248 /// Evaluation is currently within a statement.
250 /// Examples include:
252 /// 2. `let _ = EXPR;`
253 /// 3. `let x = EXPR;`
255 /// If true, then statement discards result from evaluating
256 /// the expression (such as examples 1 and 2 above).
257 ignores_expr_result: bool,
260 /// Evaluation is currently within the tail expression of a block.
262 /// Example: `{ STMT_1; STMT_2; EXPR }`
264 /// If true, then the surrounding context of the block ignores
265 /// the result of evaluating the block's tail expression.
267 /// Example: `let _ = { STMT_1; EXPR };`
268 tail_result_is_ignored: bool,
270 /// `Span` of the tail expression.
274 /// Generic mark meaning that the block occurred as a subexpression
275 /// where the result might be used.
277 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
282 fn is_tail_expr(&self) -> bool {
284 BlockFrame::TailExpr { .. } => true,
286 BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
289 fn is_statement(&self) -> bool {
291 BlockFrame::Statement { .. } => true,
293 BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
299 struct BlockContext(Vec<BlockFrame>);
301 struct Builder<'a, 'tcx> {
308 generator_kind: Option<GeneratorKind>,
310 /// The current set of scopes, updated as we traverse;
311 /// see the `scope` module for more details.
312 scopes: scope::Scopes<'tcx>,
314 /// The block-context: each time we build the code within an thir::Block,
315 /// we push a frame here tracking whether we are building a statement or
316 /// if we are pushing the tail expression of the block. This is used to
317 /// embed information in generated temps about whether they were created
318 /// for a block tail expression or not.
320 /// It would be great if we could fold this into `self.scopes`
321 /// somehow, but right now I think that is very tightly tied to
322 /// the code generation in ways that we cannot (or should not)
323 /// start just throwing new entries onto that vector in order to
324 /// distinguish the context of EXPR1 from the context of EXPR2 in
325 /// `{ STMTS; EXPR1 } + EXPR2`.
326 block_context: BlockContext,
328 /// The current unsafe block in scope, even if it is hidden by
329 /// a `PushUnsafeBlock`.
330 unpushed_unsafe: Safety,
332 /// The number of `push_unsafe_block` levels in scope.
333 push_unsafe_count: usize,
335 /// The vector of all scopes that we have created thus far;
336 /// we track this for debuginfo later.
337 source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
338 source_scope: SourceScope,
340 /// The guard-context: each time we build the guard expression for
341 /// a match arm, we push onto this stack, and then pop when we
342 /// finish building it.
343 guard_context: Vec<GuardFrame>,
345 /// Maps `HirId`s of variable bindings to the `Local`s created for them.
346 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
347 var_indices: HirIdMap<LocalsForNode>,
348 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
349 canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
350 upvar_mutbls: Vec<Mutability>,
351 unit_temp: Option<Place<'tcx>>,
353 var_debug_info: Vec<VarDebugInfo<'tcx>>,
356 impl<'a, 'tcx> Builder<'a, 'tcx> {
357 fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
358 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
361 fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
362 self.var_indices[&id].local_id(for_guard)
370 fn push(&mut self, bf: BlockFrame) {
373 fn pop(&mut self) -> Option<BlockFrame> {
377 /// Traverses the frames on the `BlockContext`, searching for either
378 /// the first block-tail expression frame with no intervening
381 /// Notably, this skips over `SubExpr` frames; this method is
382 /// meant to be used in the context of understanding the
383 /// relationship of a temp (created within some complicated
384 /// expression) with its containing expression, and whether the
385 /// value of that *containing expression* (not the temp!) is
387 fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
388 for bf in self.0.iter().rev() {
390 BlockFrame::SubExpr => continue,
391 BlockFrame::Statement { .. } => break,
392 &BlockFrame::TailExpr { tail_result_is_ignored, span } => {
393 return Some(BlockTailInfo { tail_result_is_ignored, span });
401 /// Looks at the topmost frame on the BlockContext and reports
402 /// whether its one that would discard a block tail result.
404 /// Unlike `currently_within_ignored_tail_expression`, this does
405 /// *not* skip over `SubExpr` frames: here, we want to know
406 /// whether the block result itself is discarded.
407 fn currently_ignores_tail_results(&self) -> bool {
408 match self.0.last() {
409 // no context: conservatively assume result is read
412 // sub-expression: block result feeds into some computation
413 Some(BlockFrame::SubExpr) => false,
415 // otherwise: use accumulated is_ignored state.
417 BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. }
418 | BlockFrame::Statement { ignores_expr_result: ignored },
426 /// In the usual case, a `HirId` for an identifier maps to at most
427 /// one `Local` declaration.
430 /// The exceptional case is identifiers in a match arm's pattern
431 /// that are referenced in a guard of that match arm. For these,
432 /// we have `2` Locals.
434 /// * `for_arm_body` is the Local used in the arm body (which is
435 /// just like the `One` case above),
437 /// * `ref_for_guard` is the Local used in the arm's guard (which
438 /// is a reference to a temp that is an alias of
440 ForGuard { ref_for_guard: Local, for_arm_body: Local },
444 struct GuardFrameLocal {
448 impl GuardFrameLocal {
449 fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
450 GuardFrameLocal { id }
456 /// These are the id's of names that are bound by patterns of the
457 /// arm of *this* guard.
459 /// (Frames higher up the stack will have the id's bound in arms
460 /// further out, such as in a case like:
463 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
466 /// here, when building for FIXME.
467 locals: Vec<GuardFrameLocal>,
470 /// `ForGuard` indicates whether we are talking about:
471 /// 1. The variable for use outside of guard expressions, or
472 /// 2. The temp that holds reference to (1.), which is actually what the
473 /// guard expressions see.
474 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
481 fn local_id(&self, for_guard: ForGuard) -> Local {
482 match (self, for_guard) {
483 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard)
485 &LocalsForNode::ForGuard { ref_for_guard: local_id, .. },
486 ForGuard::RefWithinGuard,
488 | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => {
492 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => {
493 bug!("anything with one local should never be within a guard.")
500 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
503 rustc_index::newtype_index! {
504 struct ScopeId { .. }
507 ///////////////////////////////////////////////////////////////////////////
508 /// The `BlockAnd` "monad" packages up the new basic block along with a
509 /// produced value (sometimes just unit, of course). The `unpack!`
510 /// macro (and methods below) makes working with `BlockAnd` much more
513 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
514 struct BlockAnd<T>(BasicBlock, T);
516 trait BlockAndExtension {
517 fn and<T>(self, v: T) -> BlockAnd<T>;
518 fn unit(self) -> BlockAnd<()>;
521 impl BlockAndExtension for BasicBlock {
522 fn and<T>(self, v: T) -> BlockAnd<T> {
526 fn unit(self) -> BlockAnd<()> {
531 /// Update a block pointer and return the value.
532 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
533 macro_rules! unpack {
534 ($x:ident = $c:expr) => {{
535 let BlockAnd(b, v) = $c;
541 let BlockAnd(b, ()) = $c;
546 fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: LocalDefId, _abi: Abi) -> bool {
547 // Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
548 let attrs = &tcx.get_attrs(fn_def_id.to_def_id());
549 let unwind_attr = attr::find_unwind_attr(&tcx.sess, attrs);
551 // We never unwind, so it's not relevant to stop an unwind.
552 if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
556 // This is a special case: some functions have a C abi but are meant to
557 // unwind anyway. Don't stop them.
559 None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
560 Some(UnwindAttr::Allowed) => false,
561 Some(UnwindAttr::Aborts) => true,
565 ///////////////////////////////////////////////////////////////////////////
566 /// the main entry point for building MIR for a function
568 struct ArgInfo<'tcx>(
571 Option<&'tcx hir::Param<'tcx>>,
572 Option<ImplicitSelfKind>,
575 fn construct_fn<'a, 'tcx, A>(
582 return_ty_span: Span,
583 body: &'tcx hir::Body<'tcx>,
587 A: Iterator<Item = ArgInfo<'tcx>>,
589 let arguments: Vec<_> = arguments.collect();
592 let tcx_hir = tcx.hir();
593 let span = tcx_hir.span(fn_id);
595 let fn_def_id = tcx_hir.local_def_id(fn_id);
597 let mut builder = Builder::new(
599 fn_def_id.to_def_id(),
608 let call_site_scope =
609 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
611 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
612 let source_info = builder.source_info(span);
613 let call_site_s = (call_site_scope, source_info);
614 unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
615 let arg_scope_s = (arg_scope, source_info);
616 // Attribute epilogue to function's closing brace
617 let fn_end = span_with_body.shrink_to_hi();
619 unpack!(builder.in_breakable_scope(None, Place::return_place(), fn_end, |builder| {
620 Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
621 builder.args_and_body(
623 fn_def_id.to_def_id(),
630 let source_info = builder.source_info(fn_end);
631 builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
632 let should_abort = should_abort_on_panic(tcx, fn_def_id, abi);
633 builder.build_drop_trees(should_abort);
637 let spread_arg = if abi == Abi::RustCall {
638 // RustCall pseudo-ABI untuples the last argument.
639 Some(Local::new(arguments.len()))
643 debug!("fn_id {:?} has attrs {:?}", fn_def_id, tcx.get_attrs(fn_def_id.to_def_id()));
645 let mut body = builder.finish();
646 body.spread_arg = spread_arg;
650 fn construct_const<'a, 'tcx>(
652 body_id: hir::BodyId,
657 let owner_id = tcx.hir().body_owner(body_id);
658 let def_id = tcx.hir().local_def_id(owner_id);
659 let span = tcx.hir().span(owner_id);
660 let mut builder = Builder::new(hir, def_id.to_def_id(), span, 0, Safety::Safe, const_ty, const_ty_span, None);
662 let mut block = START_BLOCK;
663 let ast_expr = &tcx.hir().body(body_id).value;
664 let expr = builder.hir.mirror(ast_expr);
665 unpack!(block = builder.into_expr(Place::return_place(), block, expr));
667 let source_info = builder.source_info(span);
668 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
670 builder.build_drop_trees(false);
675 /// Construct MIR for a item that has had errors in type checking.
677 /// This is required because we may still want to run MIR passes on an item
678 /// with type errors, but normal MIR construction can't handle that in general.
679 fn construct_error<'a, 'tcx>(hir: Cx<'a, 'tcx>, body_id: hir::BodyId) -> Body<'tcx> {
681 let owner_id = tcx.hir().body_owner(body_id);
682 let def_id = tcx.hir().local_def_id(owner_id);
683 let span = tcx.hir().span(owner_id);
684 let ty = tcx.ty_error();
685 let num_params = match hir.body_owner_kind {
686 hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len(),
687 hir::BodyOwnerKind::Closure => {
688 if tcx.hir().body(body_id).generator_kind().is_some() {
689 // Generators have an implicit `self` parameter *and* a possibly
690 // implicit resume parameter.
693 // The implicit self parameter adds another local in MIR.
694 1 + tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len()
697 hir::BodyOwnerKind::Const => 0,
698 hir::BodyOwnerKind::Static(_) => 0,
700 let mut builder = Builder::new(hir, def_id.to_def_id(), span, num_params, Safety::Safe, ty, span, None);
701 let source_info = builder.source_info(span);
702 // Some MIR passes will expect the number of parameters to match the
703 // function declaration.
704 for _ in 0..num_params {
705 builder.local_decls.push(LocalDecl::with_source_info(ty, source_info));
707 builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
708 let mut body = builder.finish();
709 if tcx.hir().body(body_id).generator_kind.is_some() {
710 body.yield_ty = Some(ty);
715 impl<'a, 'tcx> Builder<'a, 'tcx> {
724 generator_kind: Option<GeneratorKind>,
725 ) -> Builder<'a, 'tcx> {
726 let lint_level = LintLevel::Explicit(hir.root_lint_level);
727 let mut builder = Builder {
730 cfg: CFG { basic_blocks: IndexVec::new() },
734 scopes: scope::Scopes::new(),
735 block_context: BlockContext::new(),
736 source_scopes: IndexVec::new(),
737 source_scope: OUTERMOST_SOURCE_SCOPE,
738 guard_context: vec![],
739 push_unsafe_count: 0,
740 unpushed_unsafe: safety,
741 local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1),
742 canonical_user_type_annotations: IndexVec::new(),
743 upvar_mutbls: vec![],
744 var_indices: Default::default(),
746 var_debug_info: vec![],
749 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
751 builder.new_source_scope(span, lint_level, Some(safety)),
752 OUTERMOST_SOURCE_SCOPE
754 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
759 fn finish(self) -> Body<'tcx> {
760 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
761 if block.terminator.is_none() {
762 span_bug!(self.fn_span, "no terminator on block {:?}", index);
767 MirSource::item(self.def_id),
768 self.cfg.basic_blocks,
771 self.canonical_user_type_annotations,
781 mut block: BasicBlock,
783 arguments: &[ArgInfo<'tcx>],
784 argument_scope: region::Scope,
785 ast_body: &'tcx hir::Expr<'tcx>,
787 // Allocate locals for the function arguments
788 for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
790 SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span));
791 let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info));
793 // If this is a simple binding pattern, give debuginfo a nice name.
794 if let Some(arg) = arg_opt {
795 if let Some(ident) = arg.pat.simple_ident() {
796 self.var_debug_info.push(VarDebugInfo {
799 value: VarDebugInfoContents::Place(arg_local.into()),
805 let tcx = self.hir.tcx();
806 let tcx_hir = tcx.hir();
807 let hir_typeck_results = self.hir.typeck_results();
809 // In analyze_closure() in upvar.rs we gathered a list of upvars used by a
810 // indexed closure and we stored in a map called closure_captures in TypeckResults
811 // with the closure's DefId. Here, we run through that vec of UpvarIds for
812 // the given closure and use the necessary information to create upvar
813 // debuginfo and to fill `self.upvar_mutbls`.
814 if let Some(upvars) = hir_typeck_results.closure_captures.get(&fn_def_id) {
815 let closure_env_arg = Local::new(1);
816 let mut closure_env_projs = vec![];
817 let mut closure_ty = self.local_decls[closure_env_arg].ty;
818 if let ty::Ref(_, ty, _) = closure_ty.kind() {
819 closure_env_projs.push(ProjectionElem::Deref);
822 let upvar_substs = match closure_ty.kind() {
823 ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
824 ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
825 _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
827 let upvar_tys = upvar_substs.upvar_tys();
828 let upvars_with_tys = upvars.iter().zip(upvar_tys);
829 self.upvar_mutbls = upvars_with_tys
831 .map(|(i, ((&var_id, &upvar_id), ty))| {
832 let capture = hir_typeck_results.upvar_capture(upvar_id);
834 let mut mutability = Mutability::Not;
835 let mut name = kw::Invalid;
836 if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
837 if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
839 match hir_typeck_results
840 .extract_binding_mode(tcx.sess, pat.hir_id, pat.span)
842 Some(ty::BindByValue(hir::Mutability::Mut)) => {
843 mutability = Mutability::Mut;
845 Some(_) => mutability = Mutability::Not,
851 let mut projs = closure_env_projs.clone();
852 projs.push(ProjectionElem::Field(Field::new(i), ty));
854 ty::UpvarCapture::ByValue(_) => {}
855 ty::UpvarCapture::ByRef(..) => {
856 projs.push(ProjectionElem::Deref);
860 self.var_debug_info.push(VarDebugInfo {
862 source_info: SourceInfo::outermost(tcx_hir.span(var_id)),
863 value: VarDebugInfoContents::Place(Place {
864 local: closure_env_arg,
865 projection: tcx.intern_place_elems(&projs),
874 let mut scope = None;
875 // Bind the argument patterns
876 for (index, arg_info) in arguments.iter().enumerate() {
877 // Function arguments always get the first Local indices after the return place
878 let local = Local::new(index + 1);
879 let place = Place::from(local);
880 let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
882 // Make sure we drop (parts of) the argument even when not matched on.
884 arg_opt.as_ref().map_or(ast_body.span, |arg| arg.pat.span),
890 if let Some(arg) = arg_opt {
891 let pattern = self.hir.pattern_from_hir(&arg.pat);
892 let original_source_scope = self.source_scope;
893 let span = pattern.span;
894 self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
895 match *pattern.kind {
896 // Don't introduce extra copies for simple bindings
900 mode: BindingMode::ByValue,
904 self.local_decls[local].mutability = mutability;
905 self.local_decls[local].source_info.scope = self.source_scope;
906 self.local_decls[local].local_info = if let Some(kind) = self_binding {
907 Some(box LocalInfo::User(ClearCrossCrate::Set(
908 BindingForm::ImplicitSelf(*kind),
911 let binding_mode = ty::BindingMode::BindByValue(mutability);
912 Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
916 opt_match_place: Some((Some(place), span)),
921 self.var_indices.insert(var, LocalsForNode::One(local));
924 scope = self.declare_bindings(
928 matches::ArmHasGuard(false),
929 Some((Some(&place), span)),
931 unpack!(block = self.place_into_pattern(block, pattern, place, false));
934 self.source_scope = original_source_scope;
938 // Enter the argument pattern bindings source scope, if it exists.
939 if let Some(source_scope) = scope {
940 self.source_scope = source_scope;
943 let body = self.hir.mirror(ast_body);
944 self.into(Place::return_place(), block, body)
947 fn set_correct_source_scope_for_arg(
949 arg_hir_id: hir::HirId,
950 original_source_scope: SourceScope,
953 let tcx = self.hir.tcx();
954 let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir.root_lint_level);
955 let parent_root = tcx.maybe_lint_level_root_bounded(
956 self.source_scopes[original_source_scope]
959 .assert_crate_local()
961 self.hir.root_lint_level,
963 if current_root != parent_root {
965 self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None);
969 fn get_unit_temp(&mut self) -> Place<'tcx> {
970 match self.unit_temp {
973 let ty = self.hir.unit_ty();
974 let fn_span = self.fn_span;
975 let tmp = self.temp(ty, fn_span);
976 self.unit_temp = Some(tmp);
983 ///////////////////////////////////////////////////////////////////////////
984 // Builder methods are broken up into modules, depending on what kind
985 // of thing is being lowered. Note that they use the `unpack` macro
986 // above extensively.