| use crate::build; |
| use crate::build::expr::as_place::PlaceBuilder; |
| use crate::build::scope::DropKind; |
| use crate::thir::pattern::pat_from_hir; |
| use rustc_errors::ErrorReported; |
| use rustc_hir as hir; |
| use rustc_hir::def_id::{DefId, LocalDefId}; |
| use rustc_hir::lang_items::LangItem; |
| use rustc_hir::{GeneratorKind, HirIdMap, Node}; |
| use rustc_index::vec::{Idx, IndexVec}; |
| use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; |
| use rustc_middle::hir::place::PlaceBase as HirPlaceBase; |
| use rustc_middle::middle::region; |
| use rustc_middle::mir::*; |
| use rustc_middle::thir::{BindingMode, Expr, ExprId, LintLevel, PatKind, Thir}; |
| use rustc_middle::ty::subst::Subst; |
| use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeckResults}; |
| use rustc_span::symbol::sym; |
| use rustc_span::Span; |
| use rustc_target::spec::abi::Abi; |
| |
| use super::lints; |
| |
| crate fn mir_built<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def: ty::WithOptConstParam<LocalDefId>, |
| ) -> &'tcx rustc_data_structures::steal::Steal<Body<'tcx>> { |
| if let Some(def) = def.try_upgrade(tcx) { |
| return tcx.mir_built(def); |
| } |
| |
| let mut body = mir_build(tcx, def); |
| if def.const_param_did.is_some() { |
| assert!(matches!(body.source.instance, ty::InstanceDef::Item(_))); |
| body.source = MirSource::from_instance(ty::InstanceDef::Item(def.to_global())); |
| } |
| |
| tcx.alloc_steal_mir(body) |
| } |
| |
| /// Construct the MIR for a given `DefId`. |
| fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> { |
| let id = tcx.hir().local_def_id_to_hir_id(def.did); |
| let body_owner_kind = tcx.hir().body_owner_kind(id); |
| let typeck_results = tcx.typeck_opt_const_arg(def); |
| |
| // Ensure unsafeck and abstract const building is ran before we steal the THIR. |
| // We can't use `ensure()` for `thir_abstract_const` as it doesn't compute the query |
| // if inputs are green. This can cause ICEs when calling `thir_abstract_const` after |
| // THIR has been stolen if we haven't computed this query yet. |
| match def { |
| ty::WithOptConstParam { did, const_param_did: Some(const_param_did) } => { |
| tcx.ensure().thir_check_unsafety_for_const_arg((did, const_param_did)); |
| drop(tcx.thir_abstract_const_of_const_arg((did, const_param_did))); |
| } |
| ty::WithOptConstParam { did, const_param_did: None } => { |
| tcx.ensure().thir_check_unsafety(did); |
| drop(tcx.thir_abstract_const(did)); |
| } |
| } |
| |
| // Figure out what primary body this item has. |
| let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) { |
| Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) => { |
| (*body_id, decl.output.span(), None) |
| } |
| Node::Item(hir::Item { |
| kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id), |
| span, |
| .. |
| }) |
| | Node::ImplItem(hir::ImplItem { |
| kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id), |
| span, |
| .. |
| }) |
| | Node::TraitItem(hir::TraitItem { |
| kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)), |
| span, |
| .. |
| }) => { |
| // Use the `Span` of the `Item/ImplItem/TraitItem` as the body span, |
| // since the def span of a function does not include the body |
| (*body_id, decl.output.span(), Some(*span)) |
| } |
| Node::Item(hir::Item { |
| kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id), |
| .. |
| }) |
| | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. }) |
| | Node::TraitItem(hir::TraitItem { |
| kind: hir::TraitItemKind::Const(ty, Some(body_id)), |
| .. |
| }) => (*body_id, ty.span, None), |
| Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => { |
| (*body, tcx.hir().span(*hir_id), None) |
| } |
| |
| _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did), |
| }; |
| |
| // If we don't have a specialized span for the body, just use the |
| // normal def span. |
| let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id)); |
| |
| tcx.infer_ctxt().enter(|infcx| { |
| let body = if let Some(ErrorReported) = typeck_results.tainted_by_errors { |
| build::construct_error(&infcx, def, id, body_id, body_owner_kind) |
| } else if body_owner_kind.is_fn_or_closure() { |
| // fetch the fully liberated fn signature (that is, all bound |
| // types/lifetimes replaced) |
| let fn_sig = typeck_results.liberated_fn_sigs()[id]; |
| let fn_def_id = tcx.hir().local_def_id(id); |
| |
| let safety = match fn_sig.unsafety { |
| hir::Unsafety::Normal => Safety::Safe, |
| hir::Unsafety::Unsafe => Safety::FnUnsafe, |
| }; |
| |
| let body = tcx.hir().body(body_id); |
| let (thir, expr) = tcx.thir_body(def); |
| // We ran all queries that depended on THIR at the beginning |
| // of `mir_build`, so now we can steal it |
| let thir = thir.steal(); |
| let ty = tcx.type_of(fn_def_id); |
| let mut abi = fn_sig.abi; |
| let implicit_argument = match ty.kind() { |
| ty::Closure(..) => { |
| // HACK(eddyb) Avoid having RustCall on closures, |
| // as it adds unnecessary (and wrong) auto-tupling. |
| abi = Abi::Rust; |
| vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)] |
| } |
| ty::Generator(..) => { |
| let gen_ty = tcx.typeck_body(body_id).node_type(id); |
| |
| // The resume argument may be missing, in that case we need to provide it here. |
| // It will always be `()` in this case. |
| if body.params.is_empty() { |
| vec![ |
| ArgInfo(gen_ty, None, None, None), |
| ArgInfo(tcx.mk_unit(), None, None, None), |
| ] |
| } else { |
| vec![ArgInfo(gen_ty, None, None, None)] |
| } |
| } |
| _ => vec![], |
| }; |
| |
| let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| { |
| let owner_id = tcx.hir().body_owner(body_id); |
| let opt_ty_info; |
| let self_arg; |
| if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) { |
| opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span); |
| self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() { |
| match fn_decl.implicit_self { |
| hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm), |
| hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut), |
| hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef), |
| hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef), |
| _ => None, |
| } |
| } else { |
| None |
| }; |
| } else { |
| opt_ty_info = None; |
| self_arg = None; |
| } |
| |
| // C-variadic fns also have a `VaList` input that's not listed in `fn_sig` |
| // (as it's created inside the body itself, not passed in from outside). |
| let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() { |
| let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span)); |
| |
| tcx.type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()]) |
| } else { |
| fn_sig.inputs()[index] |
| }; |
| |
| ArgInfo(ty, opt_ty_info, Some(&arg), self_arg) |
| }); |
| |
| let arguments = implicit_argument.into_iter().chain(explicit_arguments); |
| |
| let (yield_ty, return_ty) = if body.generator_kind.is_some() { |
| let gen_ty = tcx.typeck_body(body_id).node_type(id); |
| let gen_sig = match gen_ty.kind() { |
| ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(), |
| _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty), |
| }; |
| (Some(gen_sig.yield_ty), gen_sig.return_ty) |
| } else { |
| (None, fn_sig.output()) |
| }; |
| |
| let mut mir = build::construct_fn( |
| &thir, |
| &infcx, |
| def, |
| id, |
| arguments, |
| safety, |
| abi, |
| return_ty, |
| return_ty_span, |
| body, |
| expr, |
| span_with_body, |
| ); |
| if yield_ty.is_some() { |
| mir.generator.as_mut().unwrap().yield_ty = yield_ty; |
| } |
| mir |
| } else { |
| // Get the revealed type of this const. This is *not* the adjusted |
| // type of its body, which may be a subtype of this type. For |
| // example: |
| // |
| // fn foo(_: &()) {} |
| // static X: fn(&'static ()) = foo; |
| // |
| // The adjusted type of the body of X is `for<'a> fn(&'a ())` which |
| // is not the same as the type of X. We need the type of the return |
| // place to be the type of the constant because NLL typeck will |
| // equate them. |
| |
| let return_ty = typeck_results.node_type(id); |
| |
| let (thir, expr) = tcx.thir_body(def); |
| // We ran all queries that depended on THIR at the beginning |
| // of `mir_build`, so now we can steal it |
| let thir = thir.steal(); |
| |
| build::construct_const(&thir, &infcx, expr, def, id, return_ty, return_ty_span) |
| }; |
| |
| lints::check(tcx, &body); |
| |
| // The borrow checker will replace all the regions here with its own |
| // inference variables. There's no point having non-erased regions here. |
| // The exception is `body.user_type_annotations`, which is used unmodified |
| // by borrow checking. |
| debug_assert!( |
| !(body.local_decls.has_free_regions(tcx) |
| || body.basic_blocks().has_free_regions(tcx) |
| || body.var_debug_info.has_free_regions(tcx) |
| || body.yield_ty().has_free_regions(tcx)), |
| "Unexpected free regions in MIR: {:?}", |
| body, |
| ); |
| |
| body |
| }) |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // BuildMir -- walks a crate, looking for fn items and methods to build MIR from |
| |
| fn liberated_closure_env_ty( |
| tcx: TyCtxt<'_>, |
| closure_expr_id: hir::HirId, |
| body_id: hir::BodyId, |
| ) -> Ty<'_> { |
| let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id); |
| |
| let (closure_def_id, closure_substs) = match *closure_ty.kind() { |
| ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs), |
| _ => bug!("closure expr does not have closure type: {:?}", closure_ty), |
| }; |
| |
| let bound_vars = |
| tcx.mk_bound_variable_kinds(std::iter::once(ty::BoundVariableKind::Region(ty::BrEnv))); |
| let br = |
| ty::BoundRegion { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind: ty::BrEnv }; |
| let env_region = ty::ReLateBound(ty::INNERMOST, br); |
| let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs, env_region).unwrap(); |
| tcx.erase_late_bound_regions(ty::Binder::bind_with_vars(closure_env_ty, bound_vars)) |
| } |
| |
| #[derive(Debug, PartialEq, Eq)] |
| enum BlockFrame { |
| /// Evaluation is currently within a statement. |
| /// |
| /// Examples include: |
| /// 1. `EXPR;` |
| /// 2. `let _ = EXPR;` |
| /// 3. `let x = EXPR;` |
| Statement { |
| /// If true, then statement discards result from evaluating |
| /// the expression (such as examples 1 and 2 above). |
| ignores_expr_result: bool, |
| }, |
| |
| /// Evaluation is currently within the tail expression of a block. |
| /// |
| /// Example: `{ STMT_1; STMT_2; EXPR }` |
| TailExpr { |
| /// If true, then the surrounding context of the block ignores |
| /// the result of evaluating the block's tail expression. |
| /// |
| /// Example: `let _ = { STMT_1; EXPR };` |
| tail_result_is_ignored: bool, |
| |
| /// `Span` of the tail expression. |
| span: Span, |
| }, |
| |
| /// Generic mark meaning that the block occurred as a subexpression |
| /// where the result might be used. |
| /// |
| /// Examples: `foo(EXPR)`, `match EXPR { ... }` |
| SubExpr, |
| } |
| |
| impl BlockFrame { |
| fn is_tail_expr(&self) -> bool { |
| match *self { |
| BlockFrame::TailExpr { .. } => true, |
| |
| BlockFrame::Statement { .. } | BlockFrame::SubExpr => false, |
| } |
| } |
| fn is_statement(&self) -> bool { |
| match *self { |
| BlockFrame::Statement { .. } => true, |
| |
| BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false, |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| struct BlockContext(Vec<BlockFrame>); |
| |
| struct Builder<'a, 'tcx> { |
| tcx: TyCtxt<'tcx>, |
| infcx: &'a InferCtxt<'a, 'tcx>, |
| typeck_results: &'tcx TypeckResults<'tcx>, |
| region_scope_tree: &'tcx region::ScopeTree, |
| param_env: ty::ParamEnv<'tcx>, |
| |
| thir: &'a Thir<'tcx>, |
| cfg: CFG<'tcx>, |
| |
| def_id: DefId, |
| hir_id: hir::HirId, |
| check_overflow: bool, |
| fn_span: Span, |
| arg_count: usize, |
| generator_kind: Option<GeneratorKind>, |
| |
| /// The current set of scopes, updated as we traverse; |
| /// see the `scope` module for more details. |
| scopes: scope::Scopes<'tcx>, |
| |
| /// The block-context: each time we build the code within an thir::Block, |
| /// we push a frame here tracking whether we are building a statement or |
| /// if we are pushing the tail expression of the block. This is used to |
| /// embed information in generated temps about whether they were created |
| /// for a block tail expression or not. |
| /// |
| /// It would be great if we could fold this into `self.scopes` |
| /// somehow, but right now I think that is very tightly tied to |
| /// the code generation in ways that we cannot (or should not) |
| /// start just throwing new entries onto that vector in order to |
| /// distinguish the context of EXPR1 from the context of EXPR2 in |
| /// `{ STMTS; EXPR1 } + EXPR2`. |
| block_context: BlockContext, |
| |
| /// The current unsafe block in scope |
| in_scope_unsafe: Safety, |
| |
| /// The vector of all scopes that we have created thus far; |
| /// we track this for debuginfo later. |
| source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>, |
| source_scope: SourceScope, |
| |
| /// The guard-context: each time we build the guard expression for |
| /// a match arm, we push onto this stack, and then pop when we |
| /// finish building it. |
| guard_context: Vec<GuardFrame>, |
| |
| /// Maps `HirId`s of variable bindings to the `Local`s created for them. |
| /// (A match binding can have two locals; the 2nd is for the arm's guard.) |
| var_indices: HirIdMap<LocalsForNode>, |
| local_decls: IndexVec<Local, LocalDecl<'tcx>>, |
| canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>, |
| upvar_mutbls: Vec<Mutability>, |
| unit_temp: Option<Place<'tcx>>, |
| |
| var_debug_info: Vec<VarDebugInfo<'tcx>>, |
| } |
| |
| impl<'a, 'tcx> Builder<'a, 'tcx> { |
| fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool { |
| self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id)) |
| } |
| |
| fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local { |
| self.var_indices[&id].local_id(for_guard) |
| } |
| } |
| |
| impl BlockContext { |
| fn new() -> Self { |
| BlockContext(vec![]) |
| } |
| fn push(&mut self, bf: BlockFrame) { |
| self.0.push(bf); |
| } |
| fn pop(&mut self) -> Option<BlockFrame> { |
| self.0.pop() |
| } |
| |
| /// Traverses the frames on the `BlockContext`, searching for either |
| /// the first block-tail expression frame with no intervening |
| /// statement frame. |
| /// |
| /// Notably, this skips over `SubExpr` frames; this method is |
| /// meant to be used in the context of understanding the |
| /// relationship of a temp (created within some complicated |
| /// expression) with its containing expression, and whether the |
| /// value of that *containing expression* (not the temp!) is |
| /// ignored. |
| fn currently_in_block_tail(&self) -> Option<BlockTailInfo> { |
| for bf in self.0.iter().rev() { |
| match bf { |
| BlockFrame::SubExpr => continue, |
| BlockFrame::Statement { .. } => break, |
| &BlockFrame::TailExpr { tail_result_is_ignored, span } => { |
| return Some(BlockTailInfo { tail_result_is_ignored, span }); |
| } |
| } |
| } |
| |
| None |
| } |
| |
| /// Looks at the topmost frame on the BlockContext and reports |
| /// whether its one that would discard a block tail result. |
| /// |
| /// Unlike `currently_within_ignored_tail_expression`, this does |
| /// *not* skip over `SubExpr` frames: here, we want to know |
| /// whether the block result itself is discarded. |
| fn currently_ignores_tail_results(&self) -> bool { |
| match self.0.last() { |
| // no context: conservatively assume result is read |
| None => false, |
| |
| // sub-expression: block result feeds into some computation |
| Some(BlockFrame::SubExpr) => false, |
| |
| // otherwise: use accumulated is_ignored state. |
| Some( |
| BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. } |
| | BlockFrame::Statement { ignores_expr_result: ignored }, |
| ) => *ignored, |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| enum LocalsForNode { |
| /// In the usual case, a `HirId` for an identifier maps to at most |
| /// one `Local` declaration. |
| One(Local), |
| |
| /// The exceptional case is identifiers in a match arm's pattern |
| /// that are referenced in a guard of that match arm. For these, |
| /// we have `2` Locals. |
| /// |
| /// * `for_arm_body` is the Local used in the arm body (which is |
| /// just like the `One` case above), |
| /// |
| /// * `ref_for_guard` is the Local used in the arm's guard (which |
| /// is a reference to a temp that is an alias of |
| /// `for_arm_body`). |
| ForGuard { ref_for_guard: Local, for_arm_body: Local }, |
| } |
| |
| #[derive(Debug)] |
| struct GuardFrameLocal { |
| id: hir::HirId, |
| } |
| |
| impl GuardFrameLocal { |
| fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self { |
| GuardFrameLocal { id } |
| } |
| } |
| |
| #[derive(Debug)] |
| struct GuardFrame { |
| /// These are the id's of names that are bound by patterns of the |
| /// arm of *this* guard. |
| /// |
| /// (Frames higher up the stack will have the id's bound in arms |
| /// further out, such as in a case like: |
| /// |
| /// match E1 { |
| /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1, |
| /// } |
| /// |
| /// here, when building for FIXME. |
| locals: Vec<GuardFrameLocal>, |
| } |
| |
| /// `ForGuard` indicates whether we are talking about: |
| /// 1. The variable for use outside of guard expressions, or |
| /// 2. The temp that holds reference to (1.), which is actually what the |
| /// guard expressions see. |
| #[derive(Copy, Clone, Debug, PartialEq, Eq)] |
| enum ForGuard { |
| RefWithinGuard, |
| OutsideGuard, |
| } |
| |
| impl LocalsForNode { |
| fn local_id(&self, for_guard: ForGuard) -> Local { |
| match (self, for_guard) { |
| (&LocalsForNode::One(local_id), ForGuard::OutsideGuard) |
| | ( |
| &LocalsForNode::ForGuard { ref_for_guard: local_id, .. }, |
| ForGuard::RefWithinGuard, |
| ) |
| | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => { |
| local_id |
| } |
| |
| (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => { |
| bug!("anything with one local should never be within a guard.") |
| } |
| } |
| } |
| } |
| |
| struct CFG<'tcx> { |
| basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, |
| } |
| |
| rustc_index::newtype_index! { |
| struct ScopeId { .. } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| /// The `BlockAnd` "monad" packages up the new basic block along with a |
| /// produced value (sometimes just unit, of course). The `unpack!` |
| /// macro (and methods below) makes working with `BlockAnd` much more |
| /// convenient. |
| |
| #[must_use = "if you don't use one of these results, you're leaving a dangling edge"] |
| struct BlockAnd<T>(BasicBlock, T); |
| |
| trait BlockAndExtension { |
| fn and<T>(self, v: T) -> BlockAnd<T>; |
| fn unit(self) -> BlockAnd<()>; |
| } |
| |
| impl BlockAndExtension for BasicBlock { |
| fn and<T>(self, v: T) -> BlockAnd<T> { |
| BlockAnd(self, v) |
| } |
| |
| fn unit(self) -> BlockAnd<()> { |
| BlockAnd(self, ()) |
| } |
| } |
| |
| /// Update a block pointer and return the value. |
| /// Use it like `let x = unpack!(block = self.foo(block, foo))`. |
| macro_rules! unpack { |
| ($x:ident = $c:expr) => {{ |
| let BlockAnd(b, v) = $c; |
| $x = b; |
| v |
| }}; |
| |
| ($c:expr) => {{ |
| let BlockAnd(b, ()) = $c; |
| b |
| }}; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| /// the main entry point for building MIR for a function |
| |
| struct ArgInfo<'tcx>( |
| Ty<'tcx>, |
| Option<Span>, |
| Option<&'tcx hir::Param<'tcx>>, |
| Option<ImplicitSelfKind>, |
| ); |
| |
| fn construct_fn<'tcx, A>( |
| thir: &Thir<'tcx>, |
| infcx: &InferCtxt<'_, 'tcx>, |
| fn_def: ty::WithOptConstParam<LocalDefId>, |
| fn_id: hir::HirId, |
| arguments: A, |
| safety: Safety, |
| abi: Abi, |
| return_ty: Ty<'tcx>, |
| return_ty_span: Span, |
| body: &'tcx hir::Body<'tcx>, |
| expr: ExprId, |
| span_with_body: Span, |
| ) -> Body<'tcx> |
| where |
| A: Iterator<Item = ArgInfo<'tcx>>, |
| { |
| let arguments: Vec<_> = arguments.collect(); |
| |
| let tcx = infcx.tcx; |
| let span = tcx.hir().span(fn_id); |
| |
| let mut builder = Builder::new( |
| thir, |
| infcx, |
| fn_def, |
| fn_id, |
| span_with_body, |
| arguments.len(), |
| safety, |
| return_ty, |
| return_ty_span, |
| body.generator_kind, |
| ); |
| |
| let call_site_scope = |
| region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite }; |
| let arg_scope = |
| region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments }; |
| let source_info = builder.source_info(span); |
| let call_site_s = (call_site_scope, source_info); |
| unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| { |
| let arg_scope_s = (arg_scope, source_info); |
| // Attribute epilogue to function's closing brace |
| let fn_end = span_with_body.shrink_to_hi(); |
| let return_block = |
| unpack!(builder.in_breakable_scope(None, Place::return_place(), fn_end, |builder| { |
| Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| { |
| builder.args_and_body( |
| START_BLOCK, |
| fn_def.did.to_def_id(), |
| &arguments, |
| arg_scope, |
| &thir[expr], |
| ) |
| })) |
| })); |
| let source_info = builder.source_info(fn_end); |
| builder.cfg.terminate(return_block, source_info, TerminatorKind::Return); |
| builder.build_drop_trees(); |
| return_block.unit() |
| })); |
| |
| let spread_arg = if abi == Abi::RustCall { |
| // RustCall pseudo-ABI untuples the last argument. |
| Some(Local::new(arguments.len())) |
| } else { |
| None |
| }; |
| debug!("fn_id {:?} has attrs {:?}", fn_def, tcx.get_attrs(fn_def.did.to_def_id())); |
| |
| let mut body = builder.finish(); |
| body.spread_arg = spread_arg; |
| body |
| } |
| |
| fn construct_const<'a, 'tcx>( |
| thir: &'a Thir<'tcx>, |
| infcx: &'a InferCtxt<'a, 'tcx>, |
| expr: ExprId, |
| def: ty::WithOptConstParam<LocalDefId>, |
| hir_id: hir::HirId, |
| const_ty: Ty<'tcx>, |
| const_ty_span: Span, |
| ) -> Body<'tcx> { |
| let tcx = infcx.tcx; |
| let span = tcx.hir().span(hir_id); |
| let mut builder = Builder::new( |
| thir, |
| infcx, |
| def, |
| hir_id, |
| span, |
| 0, |
| Safety::Safe, |
| const_ty, |
| const_ty_span, |
| None, |
| ); |
| |
| let mut block = START_BLOCK; |
| unpack!(block = builder.expr_into_dest(Place::return_place(), block, &thir[expr])); |
| |
| let source_info = builder.source_info(span); |
| builder.cfg.terminate(block, source_info, TerminatorKind::Return); |
| |
| builder.build_drop_trees(); |
| |
| builder.finish() |
| } |
| |
| /// Construct MIR for an item that has had errors in type checking. |
| /// |
| /// This is required because we may still want to run MIR passes on an item |
| /// with type errors, but normal MIR construction can't handle that in general. |
| fn construct_error<'a, 'tcx>( |
| infcx: &'a InferCtxt<'a, 'tcx>, |
| def: ty::WithOptConstParam<LocalDefId>, |
| hir_id: hir::HirId, |
| body_id: hir::BodyId, |
| body_owner_kind: hir::BodyOwnerKind, |
| ) -> Body<'tcx> { |
| let tcx = infcx.tcx; |
| let span = tcx.hir().span(hir_id); |
| let ty = tcx.ty_error(); |
| let generator_kind = tcx.hir().body(body_id).generator_kind; |
| let num_params = match body_owner_kind { |
| hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len(), |
| hir::BodyOwnerKind::Closure => { |
| if generator_kind.is_some() { |
| // Generators have an implicit `self` parameter *and* a possibly |
| // implicit resume parameter. |
| 2 |
| } else { |
| // The implicit self parameter adds another local in MIR. |
| 1 + tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len() |
| } |
| } |
| hir::BodyOwnerKind::Const => 0, |
| hir::BodyOwnerKind::Static(_) => 0, |
| }; |
| let mut cfg = CFG { basic_blocks: IndexVec::new() }; |
| let mut source_scopes = IndexVec::new(); |
| let mut local_decls = IndexVec::from_elem_n(LocalDecl::new(ty, span), 1); |
| |
| cfg.start_new_block(); |
| source_scopes.push(SourceScopeData { |
| span, |
| parent_scope: None, |
| inlined: None, |
| inlined_parent_scope: None, |
| local_data: ClearCrossCrate::Set(SourceScopeLocalData { |
| lint_root: hir_id, |
| safety: Safety::Safe, |
| }), |
| }); |
| let source_info = SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE }; |
| |
| // Some MIR passes will expect the number of parameters to match the |
| // function declaration. |
| for _ in 0..num_params { |
| local_decls.push(LocalDecl::with_source_info(ty, source_info)); |
| } |
| cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable); |
| |
| let mut body = Body::new( |
| tcx, |
| MirSource::item(def.did.to_def_id()), |
| cfg.basic_blocks, |
| source_scopes, |
| local_decls, |
| IndexVec::new(), |
| num_params, |
| vec![], |
| span, |
| generator_kind, |
| ); |
| body.generator.as_mut().map(|gen| gen.yield_ty = Some(ty)); |
| body |
| } |
| |
| impl<'a, 'tcx> Builder<'a, 'tcx> { |
| fn new( |
| thir: &'a Thir<'tcx>, |
| infcx: &'a InferCtxt<'a, 'tcx>, |
| def: ty::WithOptConstParam<LocalDefId>, |
| hir_id: hir::HirId, |
| span: Span, |
| arg_count: usize, |
| safety: Safety, |
| return_ty: Ty<'tcx>, |
| return_span: Span, |
| generator_kind: Option<GeneratorKind>, |
| ) -> Builder<'a, 'tcx> { |
| let tcx = infcx.tcx; |
| let attrs = tcx.hir().attrs(hir_id); |
| // Some functions always have overflow checks enabled, |
| // however, they may not get codegen'd, depending on |
| // the settings for the crate they are codegened in. |
| let mut check_overflow = tcx.sess.contains_name(attrs, sym::rustc_inherit_overflow_checks); |
| // Respect -C overflow-checks. |
| check_overflow |= tcx.sess.overflow_checks(); |
| // Constants always need overflow checks. |
| check_overflow |= matches!( |
| tcx.hir().body_owner_kind(hir_id), |
| hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) |
| ); |
| |
| let lint_level = LintLevel::Explicit(hir_id); |
| let mut builder = Builder { |
| thir, |
| tcx, |
| infcx, |
| typeck_results: tcx.typeck_opt_const_arg(def), |
| region_scope_tree: tcx.region_scope_tree(def.did), |
| param_env: tcx.param_env(def.did), |
| def_id: def.did.to_def_id(), |
| hir_id, |
| check_overflow, |
| cfg: CFG { basic_blocks: IndexVec::new() }, |
| fn_span: span, |
| arg_count, |
| generator_kind, |
| scopes: scope::Scopes::new(), |
| block_context: BlockContext::new(), |
| source_scopes: IndexVec::new(), |
| source_scope: OUTERMOST_SOURCE_SCOPE, |
| guard_context: vec![], |
| in_scope_unsafe: safety, |
| local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1), |
| canonical_user_type_annotations: IndexVec::new(), |
| upvar_mutbls: vec![], |
| var_indices: Default::default(), |
| unit_temp: None, |
| var_debug_info: vec![], |
| }; |
| |
| assert_eq!(builder.cfg.start_new_block(), START_BLOCK); |
| assert_eq!( |
| builder.new_source_scope(span, lint_level, Some(safety)), |
| OUTERMOST_SOURCE_SCOPE |
| ); |
| builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None; |
| |
| builder |
| } |
| |
| fn finish(self) -> Body<'tcx> { |
| for (index, block) in self.cfg.basic_blocks.iter().enumerate() { |
| if block.terminator.is_none() { |
| span_bug!(self.fn_span, "no terminator on block {:?}", index); |
| } |
| } |
| |
| Body::new( |
| self.tcx, |
| MirSource::item(self.def_id), |
| self.cfg.basic_blocks, |
| self.source_scopes, |
| self.local_decls, |
| self.canonical_user_type_annotations, |
| self.arg_count, |
| self.var_debug_info, |
| self.fn_span, |
| self.generator_kind, |
| ) |
| } |
| |
| fn args_and_body( |
| &mut self, |
| mut block: BasicBlock, |
| fn_def_id: DefId, |
| arguments: &[ArgInfo<'tcx>], |
| argument_scope: region::Scope, |
| expr: &Expr<'tcx>, |
| ) -> BlockAnd<()> { |
| // Allocate locals for the function arguments |
| for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() { |
| let source_info = |
| SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span)); |
| let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info)); |
| |
| // If this is a simple binding pattern, give debuginfo a nice name. |
| if let Some(arg) = arg_opt { |
| if let Some(ident) = arg.pat.simple_ident() { |
| self.var_debug_info.push(VarDebugInfo { |
| name: ident.name, |
| source_info, |
| value: VarDebugInfoContents::Place(arg_local.into()), |
| }); |
| } |
| } |
| } |
| |
| let tcx = self.tcx; |
| let tcx_hir = tcx.hir(); |
| let hir_typeck_results = self.typeck_results; |
| |
| // In analyze_closure() in upvar.rs we gathered a list of upvars used by an |
| // indexed closure and we stored in a map called closure_min_captures in TypeckResults |
| // with the closure's DefId. Here, we run through that vec of UpvarIds for |
| // the given closure and use the necessary information to create upvar |
| // debuginfo and to fill `self.upvar_mutbls`. |
| if hir_typeck_results.closure_min_captures.get(&fn_def_id).is_some() { |
| let mut closure_env_projs = vec![]; |
| let mut closure_ty = self.local_decls[ty::CAPTURE_STRUCT_LOCAL].ty; |
| if let ty::Ref(_, ty, _) = closure_ty.kind() { |
| closure_env_projs.push(ProjectionElem::Deref); |
| closure_ty = ty; |
| } |
| let upvar_substs = match closure_ty.kind() { |
| ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs), |
| ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs), |
| _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty), |
| }; |
| let def_id = self.def_id.as_local().unwrap(); |
| let capture_syms = tcx.symbols_for_closure_captures((def_id, fn_def_id)); |
| let capture_tys = upvar_substs.upvar_tys(); |
| let captures_with_tys = hir_typeck_results |
| .closure_min_captures_flattened(fn_def_id) |
| .zip(capture_tys.zip(capture_syms)); |
| |
| self.upvar_mutbls = captures_with_tys |
| .enumerate() |
| .map(|(i, (captured_place, (ty, sym)))| { |
| let capture = captured_place.info.capture_kind; |
| let var_id = match captured_place.place.base { |
| HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id, |
| _ => bug!("Expected an upvar"), |
| }; |
| |
| let mutability = captured_place.mutability; |
| |
| let mut projs = closure_env_projs.clone(); |
| projs.push(ProjectionElem::Field(Field::new(i), ty)); |
| match capture { |
| ty::UpvarCapture::ByValue(_) => {} |
| ty::UpvarCapture::ByRef(..) => { |
| projs.push(ProjectionElem::Deref); |
| } |
| }; |
| |
| self.var_debug_info.push(VarDebugInfo { |
| name: sym, |
| source_info: SourceInfo::outermost(tcx_hir.span(var_id)), |
| value: VarDebugInfoContents::Place(Place { |
| local: ty::CAPTURE_STRUCT_LOCAL, |
| projection: tcx.intern_place_elems(&projs), |
| }), |
| }); |
| |
| mutability |
| }) |
| .collect(); |
| } |
| |
| let mut scope = None; |
| // Bind the argument patterns |
| for (index, arg_info) in arguments.iter().enumerate() { |
| // Function arguments always get the first Local indices after the return place |
| let local = Local::new(index + 1); |
| let place = Place::from(local); |
| let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info; |
| |
| // Make sure we drop (parts of) the argument even when not matched on. |
| self.schedule_drop( |
| arg_opt.as_ref().map_or(expr.span, |arg| arg.pat.span), |
| argument_scope, |
| local, |
| DropKind::Value, |
| ); |
| |
| let Some(arg) = arg_opt else { |
| continue; |
| }; |
| let pat = match tcx.hir().get(arg.pat.hir_id) { |
| Node::Pat(pat) | Node::Binding(pat) => pat, |
| node => bug!("pattern became {:?}", node), |
| }; |
| let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat); |
| let original_source_scope = self.source_scope; |
| let span = pattern.span; |
| self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span); |
| match *pattern.kind { |
| // Don't introduce extra copies for simple bindings |
| PatKind::Binding { |
| mutability, |
| var, |
| mode: BindingMode::ByValue, |
| subpattern: None, |
| .. |
| } => { |
| self.local_decls[local].mutability = mutability; |
| self.local_decls[local].source_info.scope = self.source_scope; |
| self.local_decls[local].local_info = if let Some(kind) = self_binding { |
| Some(Box::new(LocalInfo::User(ClearCrossCrate::Set( |
| BindingForm::ImplicitSelf(*kind), |
| )))) |
| } else { |
| let binding_mode = ty::BindingMode::BindByValue(mutability); |
| Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var( |
| VarBindingForm { |
| binding_mode, |
| opt_ty_info, |
| opt_match_place: Some((Some(place), span)), |
| pat_span: span, |
| }, |
| ))))) |
| }; |
| self.var_indices.insert(var, LocalsForNode::One(local)); |
| } |
| _ => { |
| scope = self.declare_bindings( |
| scope, |
| expr.span, |
| &pattern, |
| matches::ArmHasGuard(false), |
| Some((Some(&place), span)), |
| ); |
| let place_builder = PlaceBuilder::from(local); |
| unpack!(block = self.place_into_pattern(block, pattern, place_builder, false)); |
| } |
| } |
| self.source_scope = original_source_scope; |
| } |
| |
| // Enter the argument pattern bindings source scope, if it exists. |
| if let Some(source_scope) = scope { |
| self.source_scope = source_scope; |
| } |
| |
| self.expr_into_dest(Place::return_place(), block, &expr) |
| } |
| |
| fn set_correct_source_scope_for_arg( |
| &mut self, |
| arg_hir_id: hir::HirId, |
| original_source_scope: SourceScope, |
| pattern_span: Span, |
| ) { |
| let tcx = self.tcx; |
| let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir_id); |
| let parent_root = tcx.maybe_lint_level_root_bounded( |
| self.source_scopes[original_source_scope] |
| .local_data |
| .as_ref() |
| .assert_crate_local() |
| .lint_root, |
| self.hir_id, |
| ); |
| if current_root != parent_root { |
| self.source_scope = |
| self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None); |
| } |
| } |
| |
| fn get_unit_temp(&mut self) -> Place<'tcx> { |
| match self.unit_temp { |
| Some(tmp) => tmp, |
| None => { |
| let ty = self.tcx.mk_unit(); |
| let fn_span = self.fn_span; |
| let tmp = self.temp(ty, fn_span); |
| self.unit_temp = Some(tmp); |
| tmp |
| } |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Builder methods are broken up into modules, depending on what kind |
| // of thing is being lowered. Note that they use the `unpack` macro |
| // above extensively. |
| |
| mod block; |
| mod cfg; |
| mod expr; |
| mod matches; |
| mod misc; |
| mod scope; |
| |
| pub(crate) use expr::category::Category as ExprCategory; |
