2 pub(crate) use crate::build::expr::as_constant::lit_to_mir_constant;
3 use crate::build::expr::as_place::PlaceBuilder;
4 use crate::build::scope::DropKind;
5 use crate::thir::pattern::pat_from_hir;
6 use rustc_apfloat::ieee::{Double, Single};
7 use rustc_apfloat::Float;
8 use rustc_data_structures::fx::FxHashMap;
9 use rustc_data_structures::sorted_map::SortedIndexMultiMap;
10 use rustc_errors::ErrorGuaranteed;
12 use rustc_hir::def_id::{DefId, LocalDefId};
13 use rustc_hir::lang_items::LangItem;
14 use rustc_hir::{GeneratorKind, Node};
15 use rustc_index::vec::{Idx, IndexVec};
16 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
17 use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
18 use rustc_middle::middle::region;
19 use rustc_middle::mir::interpret::ConstValue;
20 use rustc_middle::mir::interpret::Scalar;
21 use rustc_middle::mir::*;
22 use rustc_middle::thir::{BindingMode, Expr, ExprId, LintLevel, LocalVarId, PatKind, Thir};
23 use rustc_middle::ty::subst::Subst;
24 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable, TypeckResults};
25 use rustc_span::symbol::sym;
27 use rustc_span::Symbol;
28 use rustc_target::spec::abi::Abi;
32 pub(crate) fn mir_built<'tcx>(
34 def: ty::WithOptConstParam<LocalDefId>,
35 ) -> &'tcx rustc_data_structures::steal::Steal<Body<'tcx>> {
36 if let Some(def) = def.try_upgrade(tcx) {
37 return tcx.mir_built(def);
40 let mut body = mir_build(tcx, def);
41 if def.const_param_did.is_some() {
42 assert!(matches!(body.source.instance, ty::InstanceDef::Item(_)));
43 body.source = MirSource::from_instance(ty::InstanceDef::Item(def.to_global()));
46 tcx.alloc_steal_mir(body)
49 /// Construct the MIR for a given `DefId`.
50 fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
51 let id = tcx.hir().local_def_id_to_hir_id(def.did);
52 let body_owner_kind = tcx.hir().body_owner_kind(def.did);
53 let typeck_results = tcx.typeck_opt_const_arg(def);
55 // Ensure unsafeck and abstract const building is ran before we steal the THIR.
56 // We can't use `ensure()` for `thir_abstract_const` as it doesn't compute the query
57 // if inputs are green. This can cause ICEs when calling `thir_abstract_const` after
58 // THIR has been stolen if we haven't computed this query yet.
60 ty::WithOptConstParam { did, const_param_did: Some(const_param_did) } => {
61 tcx.ensure().thir_check_unsafety_for_const_arg((did, const_param_did));
62 drop(tcx.thir_abstract_const_of_const_arg((did, const_param_did)));
64 ty::WithOptConstParam { did, const_param_did: None } => {
65 tcx.ensure().thir_check_unsafety(did);
66 drop(tcx.thir_abstract_const(did));
70 // Figure out what primary body this item has.
71 let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
72 Node::Expr(hir::Expr {
73 kind: hir::ExprKind::Closure(hir::Closure { fn_decl, body, .. }),
75 }) => (*body, fn_decl.output.span(), None),
76 Node::Item(hir::Item {
77 kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
81 | Node::ImplItem(hir::ImplItem {
82 kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id),
86 | Node::TraitItem(hir::TraitItem {
87 kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)),
91 // Use the `Span` of the `Item/ImplItem/TraitItem` as the body span,
92 // since the def span of a function does not include the body
93 (*body_id, decl.output.span(), Some(*span))
95 Node::Item(hir::Item {
96 kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id),
99 | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
100 | Node::TraitItem(hir::TraitItem {
101 kind: hir::TraitItemKind::Const(ty, Some(body_id)),
103 }) => (*body_id, ty.span, None),
104 Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
105 (*body, tcx.hir().span(*hir_id), None)
108 _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did),
111 // If we don't have a specialized span for the body, just use the
113 let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
115 tcx.infer_ctxt().enter(|infcx| {
116 let body = if let Some(error_reported) = typeck_results.tainted_by_errors {
117 build::construct_error(&infcx, def, id, body_id, body_owner_kind, error_reported)
118 } else if body_owner_kind.is_fn_or_closure() {
119 // fetch the fully liberated fn signature (that is, all bound
120 // types/lifetimes replaced)
121 let fn_sig = typeck_results.liberated_fn_sigs()[id];
122 let fn_def_id = tcx.hir().local_def_id(id);
124 let safety = match fn_sig.unsafety {
125 hir::Unsafety::Normal => Safety::Safe,
126 hir::Unsafety::Unsafe => Safety::FnUnsafe,
129 let body = tcx.hir().body(body_id);
130 let (thir, expr) = tcx
132 .unwrap_or_else(|_| (tcx.alloc_steal_thir(Thir::new()), ExprId::from_u32(0)));
133 // We ran all queries that depended on THIR at the beginning
134 // of `mir_build`, so now we can steal it
135 let thir = thir.steal();
136 let ty = tcx.type_of(fn_def_id);
137 let mut abi = fn_sig.abi;
138 let implicit_argument = match ty.kind() {
140 // HACK(eddyb) Avoid having RustCall on closures,
141 // as it adds unnecessary (and wrong) auto-tupling.
143 vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
145 ty::Generator(..) => {
146 let gen_ty = tcx.typeck_body(body_id).node_type(id);
148 // The resume argument may be missing, in that case we need to provide it here.
149 // It will always be `()` in this case.
150 if body.params.is_empty() {
152 ArgInfo(gen_ty, None, None, None),
153 ArgInfo(tcx.mk_unit(), None, None, None),
156 vec![ArgInfo(gen_ty, None, None, None)]
162 let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
163 let owner_id = tcx.hir().body_owner(body_id);
166 if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
167 opt_ty_info = fn_decl
170 // Make sure that inferred closure args have no type span
171 .and_then(|ty| if arg.pat.span != ty.span { Some(ty.span) } else { None });
172 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
173 match fn_decl.implicit_self {
174 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
175 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
176 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
177 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
188 // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
189 // (as it's created inside the body itself, not passed in from outside).
190 let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
191 let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span));
193 tcx.bound_type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()])
195 fn_sig.inputs()[index]
198 ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
201 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
203 let (yield_ty, return_ty) = if body.generator_kind.is_some() {
204 let gen_ty = tcx.typeck_body(body_id).node_type(id);
205 let gen_sig = match gen_ty.kind() {
206 ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
207 _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
209 (Some(gen_sig.yield_ty), gen_sig.return_ty)
211 (None, fn_sig.output())
214 let mut mir = build::construct_fn(
228 if yield_ty.is_some() {
229 mir.generator.as_mut().unwrap().yield_ty = yield_ty;
233 // Get the revealed type of this const. This is *not* the adjusted
234 // type of its body, which may be a subtype of this type. For
238 // static X: fn(&'static ()) = foo;
240 // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
241 // is not the same as the type of X. We need the type of the return
242 // place to be the type of the constant because NLL typeck will
245 let return_ty = typeck_results.node_type(id);
247 let (thir, expr) = tcx
249 .unwrap_or_else(|_| (tcx.alloc_steal_thir(Thir::new()), ExprId::from_u32(0)));
250 // We ran all queries that depended on THIR at the beginning
251 // of `mir_build`, so now we can steal it
252 let thir = thir.steal();
254 let span_with_body = span_with_body.to(tcx.hir().span(body_id.hir_id));
256 build::construct_const(
268 lints::check(tcx, &body);
270 // The borrow checker will replace all the regions here with its own
271 // inference variables. There's no point having non-erased regions here.
272 // The exception is `body.user_type_annotations`, which is used unmodified
273 // by borrow checking.
275 !(body.local_decls.has_free_regions()
276 || body.basic_blocks.has_free_regions()
277 || body.var_debug_info.has_free_regions()
278 || body.yield_ty().has_free_regions()),
279 "Unexpected free regions in MIR: {:?}",
287 ///////////////////////////////////////////////////////////////////////////
288 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
290 fn liberated_closure_env_ty(
292 closure_expr_id: hir::HirId,
293 body_id: hir::BodyId,
295 let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id);
297 let ty::Closure(closure_def_id, closure_substs) = *closure_ty.kind() else {
298 bug!("closure expr does not have closure type: {:?}", closure_ty);
302 tcx.mk_bound_variable_kinds(std::iter::once(ty::BoundVariableKind::Region(ty::BrEnv)));
304 ty::BoundRegion { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind: ty::BrEnv };
305 let env_region = ty::ReLateBound(ty::INNERMOST, br);
306 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs, env_region).unwrap();
307 tcx.erase_late_bound_regions(ty::Binder::bind_with_vars(closure_env_ty, bound_vars))
310 #[derive(Debug, PartialEq, Eq)]
312 /// Evaluation is currently within a statement.
314 /// Examples include:
316 /// 2. `let _ = EXPR;`
317 /// 3. `let x = EXPR;`
319 /// If true, then statement discards result from evaluating
320 /// the expression (such as examples 1 and 2 above).
321 ignores_expr_result: bool,
324 /// Evaluation is currently within the tail expression of a block.
326 /// Example: `{ STMT_1; STMT_2; EXPR }`
328 /// If true, then the surrounding context of the block ignores
329 /// the result of evaluating the block's tail expression.
331 /// Example: `let _ = { STMT_1; EXPR };`
332 tail_result_is_ignored: bool,
334 /// `Span` of the tail expression.
338 /// Generic mark meaning that the block occurred as a subexpression
339 /// where the result might be used.
341 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
346 fn is_tail_expr(&self) -> bool {
348 BlockFrame::TailExpr { .. } => true,
350 BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
353 fn is_statement(&self) -> bool {
355 BlockFrame::Statement { .. } => true,
357 BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
363 struct BlockContext(Vec<BlockFrame>);
365 struct Builder<'a, 'tcx> {
367 infcx: &'a InferCtxt<'a, 'tcx>,
368 typeck_results: &'tcx TypeckResults<'tcx>,
369 region_scope_tree: &'tcx region::ScopeTree,
370 param_env: ty::ParamEnv<'tcx>,
372 thir: &'a Thir<'tcx>,
377 parent_module: DefId,
378 check_overflow: bool,
381 generator_kind: Option<GeneratorKind>,
383 /// The current set of scopes, updated as we traverse;
384 /// see the `scope` module for more details.
385 scopes: scope::Scopes<'tcx>,
387 /// The block-context: each time we build the code within an thir::Block,
388 /// we push a frame here tracking whether we are building a statement or
389 /// if we are pushing the tail expression of the block. This is used to
390 /// embed information in generated temps about whether they were created
391 /// for a block tail expression or not.
393 /// It would be great if we could fold this into `self.scopes`
394 /// somehow, but right now I think that is very tightly tied to
395 /// the code generation in ways that we cannot (or should not)
396 /// start just throwing new entries onto that vector in order to
397 /// distinguish the context of EXPR1 from the context of EXPR2 in
398 /// `{ STMTS; EXPR1 } + EXPR2`.
399 block_context: BlockContext,
401 /// The current unsafe block in scope
402 in_scope_unsafe: Safety,
404 /// The vector of all scopes that we have created thus far;
405 /// we track this for debuginfo later.
406 source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
407 source_scope: SourceScope,
409 /// The guard-context: each time we build the guard expression for
410 /// a match arm, we push onto this stack, and then pop when we
411 /// finish building it.
412 guard_context: Vec<GuardFrame>,
414 /// Maps `HirId`s of variable bindings to the `Local`s created for them.
415 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
416 var_indices: FxHashMap<LocalVarId, LocalsForNode>,
417 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
418 canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
419 upvars: CaptureMap<'tcx>,
420 unit_temp: Option<Place<'tcx>>,
422 var_debug_info: Vec<VarDebugInfo<'tcx>>,
425 type CaptureMap<'tcx> = SortedIndexMultiMap<usize, hir::HirId, Capture<'tcx>>;
428 struct Capture<'tcx> {
429 captured_place: &'tcx ty::CapturedPlace<'tcx>,
430 use_place: Place<'tcx>,
431 mutability: Mutability,
434 impl<'a, 'tcx> Builder<'a, 'tcx> {
435 fn is_bound_var_in_guard(&self, id: LocalVarId) -> bool {
436 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
439 fn var_local_id(&self, id: LocalVarId, for_guard: ForGuard) -> Local {
440 self.var_indices[&id].local_id(for_guard)
448 fn push(&mut self, bf: BlockFrame) {
451 fn pop(&mut self) -> Option<BlockFrame> {
455 /// Traverses the frames on the `BlockContext`, searching for either
456 /// the first block-tail expression frame with no intervening
459 /// Notably, this skips over `SubExpr` frames; this method is
460 /// meant to be used in the context of understanding the
461 /// relationship of a temp (created within some complicated
462 /// expression) with its containing expression, and whether the
463 /// value of that *containing expression* (not the temp!) is
465 fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
466 for bf in self.0.iter().rev() {
468 BlockFrame::SubExpr => continue,
469 BlockFrame::Statement { .. } => break,
470 &BlockFrame::TailExpr { tail_result_is_ignored, span } => {
471 return Some(BlockTailInfo { tail_result_is_ignored, span });
479 /// Looks at the topmost frame on the BlockContext and reports
480 /// whether its one that would discard a block tail result.
482 /// Unlike `currently_within_ignored_tail_expression`, this does
483 /// *not* skip over `SubExpr` frames: here, we want to know
484 /// whether the block result itself is discarded.
485 fn currently_ignores_tail_results(&self) -> bool {
486 match self.0.last() {
487 // no context: conservatively assume result is read
490 // sub-expression: block result feeds into some computation
491 Some(BlockFrame::SubExpr) => false,
493 // otherwise: use accumulated is_ignored state.
495 BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. }
496 | BlockFrame::Statement { ignores_expr_result: ignored },
504 /// In the usual case, a `HirId` for an identifier maps to at most
505 /// one `Local` declaration.
508 /// The exceptional case is identifiers in a match arm's pattern
509 /// that are referenced in a guard of that match arm. For these,
510 /// we have `2` Locals.
512 /// * `for_arm_body` is the Local used in the arm body (which is
513 /// just like the `One` case above),
515 /// * `ref_for_guard` is the Local used in the arm's guard (which
516 /// is a reference to a temp that is an alias of
518 ForGuard { ref_for_guard: Local, for_arm_body: Local },
522 struct GuardFrameLocal {
526 impl GuardFrameLocal {
527 fn new(id: LocalVarId, _binding_mode: BindingMode) -> Self {
528 GuardFrameLocal { id }
534 /// These are the id's of names that are bound by patterns of the
535 /// arm of *this* guard.
537 /// (Frames higher up the stack will have the id's bound in arms
538 /// further out, such as in a case like:
541 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
544 /// here, when building for FIXME.
545 locals: Vec<GuardFrameLocal>,
548 /// `ForGuard` indicates whether we are talking about:
549 /// 1. The variable for use outside of guard expressions, or
550 /// 2. The temp that holds reference to (1.), which is actually what the
551 /// guard expressions see.
552 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
559 fn local_id(&self, for_guard: ForGuard) -> Local {
560 match (self, for_guard) {
561 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard)
563 &LocalsForNode::ForGuard { ref_for_guard: local_id, .. },
564 ForGuard::RefWithinGuard,
566 | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => {
570 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => {
571 bug!("anything with one local should never be within a guard.")
578 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
581 rustc_index::newtype_index! {
582 struct ScopeId { .. }
586 enum NeedsTemporary {
587 /// Use this variant when whatever you are converting with `as_operand`
588 /// is the last thing you are converting. This means that if we introduced
589 /// an intermediate temporary, we'd only read it immediately after, so we can
592 /// For all cases where you aren't sure or that are too expensive to compute
593 /// for now. It is always safe to fall back to this.
597 ///////////////////////////////////////////////////////////////////////////
598 /// The `BlockAnd` "monad" packages up the new basic block along with a
599 /// produced value (sometimes just unit, of course). The `unpack!`
600 /// macro (and methods below) makes working with `BlockAnd` much more
603 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
604 struct BlockAnd<T>(BasicBlock, T);
606 trait BlockAndExtension {
607 fn and<T>(self, v: T) -> BlockAnd<T>;
608 fn unit(self) -> BlockAnd<()>;
611 impl BlockAndExtension for BasicBlock {
612 fn and<T>(self, v: T) -> BlockAnd<T> {
616 fn unit(self) -> BlockAnd<()> {
621 /// Update a block pointer and return the value.
622 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
623 macro_rules! unpack {
624 ($x:ident = $c:expr) => {{
625 let BlockAnd(b, v) = $c;
631 let BlockAnd(b, ()) = $c;
636 ///////////////////////////////////////////////////////////////////////////
637 /// the main entry point for building MIR for a function
639 struct ArgInfo<'tcx>(
642 Option<&'tcx hir::Param<'tcx>>,
643 Option<ImplicitSelfKind>,
646 fn construct_fn<'tcx, A>(
648 infcx: &InferCtxt<'_, 'tcx>,
649 fn_def: ty::WithOptConstParam<LocalDefId>,
655 return_ty_span: Span,
656 body: &'tcx hir::Body<'tcx>,
658 span_with_body: Span,
661 A: Iterator<Item = ArgInfo<'tcx>>,
663 let arguments: Vec<_> = arguments.collect();
666 let span = tcx.hir().span(fn_id);
668 let mut builder = Builder::new(
681 let call_site_scope =
682 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
684 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
685 let source_info = builder.source_info(span);
686 let call_site_s = (call_site_scope, source_info);
687 unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
688 let arg_scope_s = (arg_scope, source_info);
689 // Attribute epilogue to function's closing brace
690 let fn_end = span_with_body.shrink_to_hi();
692 unpack!(builder.in_breakable_scope(None, Place::return_place(), fn_end, |builder| {
693 Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
694 builder.args_and_body(
703 let source_info = builder.source_info(fn_end);
704 builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
705 builder.build_drop_trees();
709 let spread_arg = if abi == Abi::RustCall {
710 // RustCall pseudo-ABI untuples the last argument.
711 Some(Local::new(arguments.len()))
716 let mut body = builder.finish();
717 body.spread_arg = spread_arg;
721 fn construct_const<'a, 'tcx>(
722 thir: &'a Thir<'tcx>,
723 infcx: &'a InferCtxt<'a, 'tcx>,
725 def: ty::WithOptConstParam<LocalDefId>,
731 let mut builder = Builder::new(
744 let mut block = START_BLOCK;
745 unpack!(block = builder.expr_into_dest(Place::return_place(), block, &thir[expr]));
747 let source_info = builder.source_info(span);
748 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
750 builder.build_drop_trees();
755 /// Construct MIR for an item that has had errors in type checking.
757 /// This is required because we may still want to run MIR passes on an item
758 /// with type errors, but normal MIR construction can't handle that in general.
759 fn construct_error<'a, 'tcx>(
760 infcx: &'a InferCtxt<'a, 'tcx>,
761 def: ty::WithOptConstParam<LocalDefId>,
763 body_id: hir::BodyId,
764 body_owner_kind: hir::BodyOwnerKind,
765 err: ErrorGuaranteed,
768 let span = tcx.hir().span(hir_id);
769 let ty = tcx.ty_error();
770 let generator_kind = tcx.hir().body(body_id).generator_kind;
771 let num_params = match body_owner_kind {
772 hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len(),
773 hir::BodyOwnerKind::Closure => {
774 if generator_kind.is_some() {
775 // Generators have an implicit `self` parameter *and* a possibly
776 // implicit resume parameter.
779 // The implicit self parameter adds another local in MIR.
780 1 + tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len()
783 hir::BodyOwnerKind::Const => 0,
784 hir::BodyOwnerKind::Static(_) => 0,
786 let mut cfg = CFG { basic_blocks: IndexVec::new() };
787 let mut source_scopes = IndexVec::new();
788 let mut local_decls = IndexVec::from_elem_n(LocalDecl::new(ty, span), 1);
790 cfg.start_new_block();
791 source_scopes.push(SourceScopeData {
795 inlined_parent_scope: None,
796 local_data: ClearCrossCrate::Set(SourceScopeLocalData {
798 safety: Safety::Safe,
801 let source_info = SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE };
803 // Some MIR passes will expect the number of parameters to match the
804 // function declaration.
805 for _ in 0..num_params {
806 local_decls.push(LocalDecl::with_source_info(ty, source_info));
808 cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
810 let mut body = Body::new(
811 MirSource::item(def.did.to_def_id()),
822 body.generator.as_mut().map(|gen| gen.yield_ty = Some(ty));
826 impl<'a, 'tcx> Builder<'a, 'tcx> {
828 thir: &'a Thir<'tcx>,
829 infcx: &'a InferCtxt<'a, 'tcx>,
830 def: ty::WithOptConstParam<LocalDefId>,
837 generator_kind: Option<GeneratorKind>,
838 ) -> Builder<'a, 'tcx> {
840 let attrs = tcx.hir().attrs(hir_id);
841 // Some functions always have overflow checks enabled,
842 // however, they may not get codegen'd, depending on
843 // the settings for the crate they are codegened in.
844 let mut check_overflow = tcx.sess.contains_name(attrs, sym::rustc_inherit_overflow_checks);
845 // Respect -C overflow-checks.
846 check_overflow |= tcx.sess.overflow_checks();
847 // Constants always need overflow checks.
848 check_overflow |= matches!(
849 tcx.hir().body_owner_kind(def.did),
850 hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_)
853 let lint_level = LintLevel::Explicit(hir_id);
854 let param_env = tcx.param_env(def.did);
855 let mut builder = Builder {
859 typeck_results: tcx.typeck_opt_const_arg(def),
860 region_scope_tree: tcx.region_scope_tree(def.did),
862 def_id: def.did.to_def_id(),
864 parent_module: tcx.parent_module(hir_id).to_def_id(),
866 cfg: CFG { basic_blocks: IndexVec::new() },
870 scopes: scope::Scopes::new(),
871 block_context: BlockContext::new(),
872 source_scopes: IndexVec::new(),
873 source_scope: OUTERMOST_SOURCE_SCOPE,
874 guard_context: vec![],
875 in_scope_unsafe: safety,
876 local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1),
877 canonical_user_type_annotations: IndexVec::new(),
878 upvars: CaptureMap::new(),
879 var_indices: Default::default(),
881 var_debug_info: vec![],
884 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
886 builder.new_source_scope(span, lint_level, Some(safety)),
887 OUTERMOST_SOURCE_SCOPE
889 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
894 fn finish(self) -> Body<'tcx> {
895 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
896 if block.terminator.is_none() {
897 span_bug!(self.fn_span, "no terminator on block {:?}", index);
902 MirSource::item(self.def_id),
903 self.cfg.basic_blocks,
906 self.canonical_user_type_annotations,
911 self.typeck_results.tainted_by_errors,
917 mut block: BasicBlock,
918 fn_def_id: LocalDefId,
919 arguments: &[ArgInfo<'tcx>],
920 argument_scope: region::Scope,
923 // Allocate locals for the function arguments
924 for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
926 SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span));
927 let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info));
929 // If this is a simple binding pattern, give debuginfo a nice name.
930 if let Some(arg) = arg_opt && let Some(ident) = arg.pat.simple_ident() {
931 self.var_debug_info.push(VarDebugInfo {
934 value: VarDebugInfoContents::Place(arg_local.into()),
940 let tcx_hir = tcx.hir();
941 let hir_typeck_results = self.typeck_results;
943 // In analyze_closure() in upvar.rs we gathered a list of upvars used by an
944 // indexed closure and we stored in a map called closure_min_captures in TypeckResults
945 // with the closure's DefId. Here, we run through that vec of UpvarIds for
946 // the given closure and use the necessary information to create upvar
947 // debuginfo and to fill `self.upvars`.
948 if hir_typeck_results.closure_min_captures.get(&fn_def_id).is_some() {
949 let mut closure_env_projs = vec![];
950 let mut closure_ty = self.local_decls[ty::CAPTURE_STRUCT_LOCAL].ty;
951 if let ty::Ref(_, ty, _) = closure_ty.kind() {
952 closure_env_projs.push(ProjectionElem::Deref);
955 let upvar_substs = match closure_ty.kind() {
956 ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
957 ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
958 _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
960 let def_id = self.def_id.as_local().unwrap();
961 let capture_syms = tcx.symbols_for_closure_captures((def_id, fn_def_id));
962 let capture_tys = upvar_substs.upvar_tys();
963 let captures_with_tys = hir_typeck_results
964 .closure_min_captures_flattened(fn_def_id)
965 .zip(capture_tys.zip(capture_syms));
967 self.upvars = captures_with_tys
969 .map(|(i, (captured_place, (ty, sym)))| {
970 let capture = captured_place.info.capture_kind;
971 let var_id = match captured_place.place.base {
972 HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id,
973 _ => bug!("Expected an upvar"),
976 let mutability = captured_place.mutability;
978 let mut projs = closure_env_projs.clone();
979 projs.push(ProjectionElem::Field(Field::new(i), ty));
981 ty::UpvarCapture::ByValue => {}
982 ty::UpvarCapture::ByRef(..) => {
983 projs.push(ProjectionElem::Deref);
987 let use_place = Place {
988 local: ty::CAPTURE_STRUCT_LOCAL,
989 projection: tcx.intern_place_elems(&projs),
991 self.var_debug_info.push(VarDebugInfo {
993 source_info: SourceInfo::outermost(tcx_hir.span(var_id)),
994 value: VarDebugInfoContents::Place(use_place),
997 let capture = Capture { captured_place, use_place, mutability };
1003 let mut scope = None;
1004 // Bind the argument patterns
1005 for (index, arg_info) in arguments.iter().enumerate() {
1006 // Function arguments always get the first Local indices after the return place
1007 let local = Local::new(index + 1);
1008 let place = Place::from(local);
1009 let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
1011 // Make sure we drop (parts of) the argument even when not matched on.
1013 arg_opt.as_ref().map_or(expr.span, |arg| arg.pat.span),
1019 let Some(arg) = arg_opt else {
1022 let pat = match tcx.hir().get(arg.pat.hir_id) {
1023 Node::Pat(pat) => pat,
1024 node => bug!("pattern became {:?}", node),
1026 let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat);
1027 let original_source_scope = self.source_scope;
1028 let span = pattern.span;
1029 self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
1030 match pattern.kind {
1031 // Don't introduce extra copies for simple bindings
1035 mode: BindingMode::ByValue,
1039 self.local_decls[local].mutability = mutability;
1040 self.local_decls[local].source_info.scope = self.source_scope;
1041 self.local_decls[local].local_info = if let Some(kind) = self_binding {
1042 Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(
1043 BindingForm::ImplicitSelf(*kind),
1046 let binding_mode = ty::BindingMode::BindByValue(mutability);
1047 Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
1051 opt_match_place: Some((None, span)),
1056 self.var_indices.insert(var, LocalsForNode::One(local));
1059 scope = self.declare_bindings(
1063 matches::ArmHasGuard(false),
1064 Some((Some(&place), span)),
1066 let place_builder = PlaceBuilder::from(local);
1069 self.place_into_pattern(block, pattern.as_ref(), place_builder, false)
1073 self.source_scope = original_source_scope;
1076 // Enter the argument pattern bindings source scope, if it exists.
1077 if let Some(source_scope) = scope {
1078 self.source_scope = source_scope;
1081 self.expr_into_dest(Place::return_place(), block, &expr)
1084 fn set_correct_source_scope_for_arg(
1086 arg_hir_id: hir::HirId,
1087 original_source_scope: SourceScope,
1091 let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir_id);
1092 let parent_root = tcx.maybe_lint_level_root_bounded(
1093 self.source_scopes[original_source_scope]
1096 .assert_crate_local()
1100 if current_root != parent_root {
1102 self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None);
1106 fn get_unit_temp(&mut self) -> Place<'tcx> {
1107 match self.unit_temp {
1110 let ty = self.tcx.mk_unit();
1111 let fn_span = self.fn_span;
1112 let tmp = self.temp(ty, fn_span);
1113 self.unit_temp = Some(tmp);
1120 fn parse_float_into_constval<'tcx>(
1122 float_ty: ty::FloatTy,
1124 ) -> Option<ConstValue<'tcx>> {
1125 parse_float_into_scalar(num, float_ty, neg).map(ConstValue::Scalar)
1128 pub(crate) fn parse_float_into_scalar(
1130 float_ty: ty::FloatTy,
1132 ) -> Option<Scalar> {
1133 let num = num.as_str();
1135 ty::FloatTy::F32 => {
1136 let Ok(rust_f) = num.parse::<f32>() else { return None };
1137 let mut f = num.parse::<Single>().unwrap_or_else(|e| {
1138 panic!("apfloat::ieee::Single failed to parse `{}`: {:?}", num, e)
1142 u128::from(rust_f.to_bits()) == f.to_bits(),
1143 "apfloat::ieee::Single gave different result for `{}`: \
1144 {}({:#x}) vs Rust's {}({:#x})",
1148 Single::from_bits(rust_f.to_bits().into()),
1156 Some(Scalar::from_f32(f))
1158 ty::FloatTy::F64 => {
1159 let Ok(rust_f) = num.parse::<f64>() else { return None };
1160 let mut f = num.parse::<Double>().unwrap_or_else(|e| {
1161 panic!("apfloat::ieee::Double failed to parse `{}`: {:?}", num, e)
1165 u128::from(rust_f.to_bits()) == f.to_bits(),
1166 "apfloat::ieee::Double gave different result for `{}`: \
1167 {}({:#x}) vs Rust's {}({:#x})",
1171 Double::from_bits(rust_f.to_bits().into()),
1179 Some(Scalar::from_f64(f))
1184 ///////////////////////////////////////////////////////////////////////////
1185 // Builder methods are broken up into modules, depending on what kind
1186 // of thing is being lowered. Note that they use the `unpack` macro
1187 // above extensively.
1196 pub(crate) use expr::category::Category as ExprCategory;