use crate::build; pub(crate) use crate::build::expr::as_constant::lit_to_mir_constant; use crate::build::expr::as_place::PlaceBuilder; use crate::build::scope::DropKind; use crate::thir::pattern::pat_from_hir; use rustc_apfloat::ieee::{Double, Single}; use rustc_apfloat::Float; use rustc_data_structures::fx::FxHashMap; use rustc_errors::ErrorGuaranteed; use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::lang_items::LangItem; use rustc_hir::{GeneratorKind, 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::interpret::ConstValue; use rustc_middle::mir::interpret::Scalar; use rustc_middle::mir::*; use rustc_middle::thir::{BindingMode, Expr, ExprId, LintLevel, LocalVarId, PatKind, Thir}; use rustc_middle::ty::subst::Subst; use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable, TypeckResults}; use rustc_span::symbol::sym; use rustc_span::Span; use rustc_span::Symbol; use rustc_target::spec::abi::Abi; use super::lints; pub(crate) fn mir_built<'tcx>( tcx: TyCtxt<'tcx>, def: ty::WithOptConstParam, ) -> &'tcx rustc_data_structures::steal::Steal> { 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) -> Body<'_> { let id = tcx.hir().local_def_id_to_hir_id(def.did); let body_owner_kind = tcx.hir().body_owner_kind(def.did); 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(hir::Closure { fn_decl, body, .. }), .. }) => (*body, fn_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(error_reported) = typeck_results.tainted_by_errors { build::construct_error(&infcx, def, id, body_id, body_owner_kind, error_reported) } 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) .unwrap_or_else(|_| (tcx.alloc_steal_thir(Thir::new()), ExprId::from_u32(0))); // 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) // Make sure that inferred closure args have no type span .and_then(|ty| if arg.pat.span != ty.span { Some(ty.span) } else { None }); 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.bound_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) .unwrap_or_else(|_| (tcx.alloc_steal_thir(Thir::new()), ExprId::from_u32(0))); // 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() || body.basic_blocks().has_free_regions() || body.var_debug_info.has_free_regions() || body.yield_ty().has_free_regions()), "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 ty::Closure(closure_def_id, closure_substs) = *closure_ty.kind() else { 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); 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, parent_module: DefId, check_overflow: bool, fn_span: Span, arg_count: usize, generator_kind: Option, /// 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>, 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, /// 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: FxHashMap, local_decls: IndexVec>, canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>, upvar_mutbls: Vec, unit_temp: Option>, var_debug_info: Vec>, } impl<'a, 'tcx> Builder<'a, 'tcx> { fn is_bound_var_in_guard(&self, id: LocalVarId) -> bool { self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id)) } fn var_local_id(&self, id: LocalVarId, 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 { 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 { 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: LocalVarId, } impl GuardFrameLocal { fn new(id: LocalVarId, _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, } /// `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>, } rustc_index::newtype_index! { struct ScopeId { .. } } #[derive(Debug)] enum NeedsTemporary { /// Use this variant when whatever you are converting with `as_operand` /// is the last thing you are converting. This means that if we introduced /// an intermediate temporary, we'd only read it immediately after, so we can /// also avoid it. No, /// For all cases where you aren't sure or that are too expensive to compute /// for now. It is always safe to fall back to this. Maybe, } /////////////////////////////////////////////////////////////////////////// /// 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(BasicBlock, T); trait BlockAndExtension { fn and(self, v: T) -> BlockAnd; fn unit(self) -> BlockAnd<()>; } impl BlockAndExtension for BasicBlock { fn and(self, v: T) -> BlockAnd { 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, Option<&'tcx hir::Param<'tcx>>, Option, ); fn construct_fn<'tcx, A>( thir: &Thir<'tcx>, infcx: &InferCtxt<'_, 'tcx>, fn_def: ty::WithOptConstParam, 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>, { 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, &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 }; 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, 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, hir_id: hir::HirId, body_id: hir::BodyId, body_owner_kind: hir::BodyOwnerKind, err: ErrorGuaranteed, ) -> 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( MirSource::item(def.did.to_def_id()), cfg.basic_blocks, source_scopes, local_decls, IndexVec::new(), num_params, vec![], span, generator_kind, Some(err), ); 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, hir_id: hir::HirId, span: Span, arg_count: usize, safety: Safety, return_ty: Ty<'tcx>, return_span: Span, generator_kind: Option, ) -> 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(def.did), hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) ); let lint_level = LintLevel::Explicit(hir_id); let param_env = tcx.param_env(def.did); 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, def_id: def.did.to_def_id(), hir_id, parent_module: tcx.parent_module(hir_id).to_def_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( 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, self.typeck_results.tainted_by_errors, ) } fn args_and_body( &mut self, mut block: BasicBlock, fn_def_id: LocalDefId, 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 && 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) => 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 } } } } fn parse_float_into_constval<'tcx>( num: Symbol, float_ty: ty::FloatTy, neg: bool, ) -> Option> { parse_float_into_scalar(num, float_ty, neg).map(ConstValue::Scalar) } pub(crate) fn parse_float_into_scalar( num: Symbol, float_ty: ty::FloatTy, neg: bool, ) -> Option { let num = num.as_str(); match float_ty { ty::FloatTy::F32 => { let Ok(rust_f) = num.parse::() else { return None }; let mut f = num.parse::().unwrap_or_else(|e| { panic!("apfloat::ieee::Single failed to parse `{}`: {:?}", num, e) }); assert!( u128::from(rust_f.to_bits()) == f.to_bits(), "apfloat::ieee::Single gave different result for `{}`: \ {}({:#x}) vs Rust's {}({:#x})", rust_f, f, f.to_bits(), Single::from_bits(rust_f.to_bits().into()), rust_f.to_bits() ); if neg { f = -f; } Some(Scalar::from_f32(f)) } ty::FloatTy::F64 => { let Ok(rust_f) = num.parse::() else { return None }; let mut f = num.parse::().unwrap_or_else(|e| { panic!("apfloat::ieee::Double failed to parse `{}`: {:?}", num, e) }); assert!( u128::from(rust_f.to_bits()) == f.to_bits(), "apfloat::ieee::Double gave different result for `{}`: \ {}({:#x}) vs Rust's {}({:#x})", rust_f, f, f.to_bits(), Double::from_bits(rust_f.to_bits().into()), rust_f.to_bits() ); if neg { f = -f; } Some(Scalar::from_f64(f)) } } } /////////////////////////////////////////////////////////////////////////// // 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;