994 lines
36 KiB
Rust
994 lines
36 KiB
Rust
use crate::build;
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use crate::build::scope::DropKind;
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use crate::hair::cx::Cx;
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use crate::hair::{LintLevel, BindingMode, PatKind};
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use crate::transform::MirSource;
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use crate::util as mir_util;
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use rustc::hir;
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use rustc::hir::{Node, GeneratorKind};
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use rustc::hir::def_id::DefId;
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use rustc::middle::lang_items;
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use rustc::middle::region;
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use rustc::mir::*;
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use rustc::ty::{self, Ty, TyCtxt};
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use rustc::ty::subst::Subst;
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use rustc::util::nodemap::HirIdMap;
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use rustc_target::spec::PanicStrategy;
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use rustc_index::vec::{IndexVec, Idx};
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use std::u32;
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use rustc_target::spec::abi::Abi;
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use syntax::attr::{self, UnwindAttr};
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use syntax::symbol::kw;
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use syntax_pos::Span;
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use super::lints;
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/// Construct the MIR for a given `DefId`.
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pub fn mir_build(tcx: TyCtxt<'_>, def_id: DefId) -> Body<'_> {
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let id = tcx.hir().as_local_hir_id(def_id).unwrap();
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// Figure out what primary body this item has.
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let (body_id, return_ty_span) = match tcx.hir().get(id) {
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Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. })
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| Node::Item(
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hir::Item {
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kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
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..
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}
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)
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| Node::ImplItem(
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hir::ImplItem {
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kind: hir::ImplItemKind::Method(hir::FnSig { decl, .. }, body_id),
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..
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}
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)
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| Node::TraitItem(
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hir::TraitItem {
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kind: hir::TraitItemKind::Method(
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hir::FnSig { decl, .. },
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hir::TraitMethod::Provided(body_id),
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),
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..
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}
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) => {
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(*body_id, decl.output.span())
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}
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Node::Item(hir::Item { kind: hir::ItemKind::Static(ty, _, body_id), .. })
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| Node::Item(hir::Item { kind: hir::ItemKind::Const(ty, body_id), .. })
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| Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
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| Node::TraitItem(
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hir::TraitItem { kind: hir::TraitItemKind::Const(ty, Some(body_id)), .. }
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) => {
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(*body_id, ty.span)
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}
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Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
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(*body, tcx.hir().span(*hir_id))
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}
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_ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def_id),
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};
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tcx.infer_ctxt().enter(|infcx| {
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let cx = Cx::new(&infcx, id);
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let body = if cx.tables().tainted_by_errors {
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build::construct_error(cx, body_id)
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} else if cx.body_owner_kind.is_fn_or_closure() {
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// fetch the fully liberated fn signature (that is, all bound
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// types/lifetimes replaced)
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let fn_sig = cx.tables().liberated_fn_sigs()[id].clone();
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let fn_def_id = tcx.hir().local_def_id(id);
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let ty = tcx.type_of(fn_def_id);
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let mut abi = fn_sig.abi;
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let implicit_argument = match ty.kind {
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ty::Closure(..) => {
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// HACK(eddyb) Avoid having RustCall on closures,
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// as it adds unnecessary (and wrong) auto-tupling.
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abi = Abi::Rust;
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Some(ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None))
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}
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ty::Generator(..) => {
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let gen_ty = tcx.body_tables(body_id).node_type(id);
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Some(ArgInfo(gen_ty, None, None, None))
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}
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_ => None,
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};
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let safety = match fn_sig.unsafety {
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hir::Unsafety::Normal => Safety::Safe,
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hir::Unsafety::Unsafe => Safety::FnUnsafe,
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};
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let body = tcx.hir().body(body_id);
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let explicit_arguments =
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body.params
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.iter()
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.enumerate()
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.map(|(index, arg)| {
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let owner_id = tcx.hir().body_owner(body_id);
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let opt_ty_info;
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let self_arg;
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if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
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opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
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self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
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match fn_decl.implicit_self {
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hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
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hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
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hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
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hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
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_ => None,
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}
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} else {
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None
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};
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} else {
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opt_ty_info = None;
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self_arg = None;
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}
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// C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
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// (as it's created inside the body itself, not passed in from outside).
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let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
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let va_list_did = tcx.require_lang_item(
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lang_items::VaListTypeLangItem,
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Some(arg.span),
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);
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let region = tcx.mk_region(ty::ReScope(region::Scope {
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id: body.value.hir_id.local_id,
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data: region::ScopeData::CallSite
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}));
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tcx.type_of(va_list_did).subst(tcx, &[region.into()])
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} else {
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fn_sig.inputs()[index]
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};
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ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
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});
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let arguments = implicit_argument.into_iter().chain(explicit_arguments);
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let (yield_ty, return_ty) = if body.generator_kind.is_some() {
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let gen_sig = match ty.kind {
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ty::Generator(gen_def_id, gen_substs, ..) =>
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gen_substs.as_generator().sig(gen_def_id, tcx),
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_ =>
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span_bug!(tcx.hir().span(id),
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"generator w/o generator type: {:?}", ty),
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};
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(Some(gen_sig.yield_ty), gen_sig.return_ty)
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} else {
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(None, fn_sig.output())
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};
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let mut mir = build::construct_fn(
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cx,
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id,
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arguments,
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safety,
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abi,
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return_ty,
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return_ty_span,
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body,
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);
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mir.yield_ty = yield_ty;
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mir
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} else {
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// Get the revealed type of this const. This is *not* the adjusted
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// type of its body, which may be a subtype of this type. For
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// example:
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//
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// fn foo(_: &()) {}
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// static X: fn(&'static ()) = foo;
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//
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// The adjusted type of the body of X is `for<'a> fn(&'a ())` which
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// is not the same as the type of X. We need the type of the return
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// place to be the type of the constant because NLL typeck will
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// equate them.
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let return_ty = cx.tables().node_type(id);
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build::construct_const(cx, body_id, return_ty, return_ty_span)
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};
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mir_util::dump_mir(tcx, None, "mir_map", &0,
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MirSource::item(def_id), &body, |_, _| Ok(()) );
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lints::check(tcx, &body, def_id);
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body
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})
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}
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///////////////////////////////////////////////////////////////////////////
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// BuildMir -- walks a crate, looking for fn items and methods to build MIR from
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fn liberated_closure_env_ty(
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tcx: TyCtxt<'_>,
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closure_expr_id: hir::HirId,
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body_id: hir::BodyId,
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) -> Ty<'_> {
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let closure_ty = tcx.body_tables(body_id).node_type(closure_expr_id);
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let (closure_def_id, closure_substs) = match closure_ty.kind {
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ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
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_ => bug!("closure expr does not have closure type: {:?}", closure_ty)
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};
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let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
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tcx.liberate_late_bound_regions(closure_def_id, &closure_env_ty)
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}
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#[derive(Debug, PartialEq, Eq)]
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pub enum BlockFrame {
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/// Evaluation is currently within a statement.
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///
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/// Examples include:
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/// 1. `EXPR;`
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/// 2. `let _ = EXPR;`
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/// 3. `let x = EXPR;`
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Statement {
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/// If true, then statement discards result from evaluating
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/// the expression (such as examples 1 and 2 above).
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ignores_expr_result: bool
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},
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/// Evaluation is currently within the tail expression of a block.
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///
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/// Example: `{ STMT_1; STMT_2; EXPR }`
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TailExpr {
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/// If true, then the surrounding context of the block ignores
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/// the result of evaluating the block's tail expression.
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///
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/// Example: `let _ = { STMT_1; EXPR };`
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tail_result_is_ignored: bool
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},
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/// Generic mark meaning that the block occurred as a subexpression
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/// where the result might be used.
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///
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/// Examples: `foo(EXPR)`, `match EXPR { ... }`
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SubExpr,
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}
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impl BlockFrame {
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fn is_tail_expr(&self) -> bool {
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match *self {
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BlockFrame::TailExpr { .. } => true,
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BlockFrame::Statement { .. } |
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BlockFrame::SubExpr => false,
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}
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}
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fn is_statement(&self) -> bool {
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match *self {
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BlockFrame::Statement { .. } => true,
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BlockFrame::TailExpr { .. } |
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BlockFrame::SubExpr => false,
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}
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}
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}
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#[derive(Debug)]
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struct BlockContext(Vec<BlockFrame>);
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struct Builder<'a, 'tcx> {
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hir: Cx<'a, 'tcx>,
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cfg: CFG<'tcx>,
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fn_span: Span,
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arg_count: usize,
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generator_kind: Option<GeneratorKind>,
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/// The current set of scopes, updated as we traverse;
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/// see the `scope` module for more details.
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scopes: scope::Scopes<'tcx>,
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/// The block-context: each time we build the code within an hair::Block,
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/// we push a frame here tracking whether we are building a statement or
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/// if we are pushing the tail expression of the block. This is used to
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/// embed information in generated temps about whether they were created
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/// for a block tail expression or not.
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///
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/// It would be great if we could fold this into `self.scopes`
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/// somehow, but right now I think that is very tightly tied to
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/// the code generation in ways that we cannot (or should not)
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/// start just throwing new entries onto that vector in order to
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/// distinguish the context of EXPR1 from the context of EXPR2 in
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/// `{ STMTS; EXPR1 } + EXPR2`.
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block_context: BlockContext,
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/// The current unsafe block in scope, even if it is hidden by
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/// a `PushUnsafeBlock`.
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unpushed_unsafe: Safety,
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/// The number of `push_unsafe_block` levels in scope.
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push_unsafe_count: usize,
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/// The vector of all scopes that we have created thus far;
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/// we track this for debuginfo later.
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source_scopes: IndexVec<SourceScope, SourceScopeData>,
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source_scope_local_data: IndexVec<SourceScope, SourceScopeLocalData>,
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source_scope: SourceScope,
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/// The guard-context: each time we build the guard expression for
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/// a match arm, we push onto this stack, and then pop when we
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/// finish building it.
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guard_context: Vec<GuardFrame>,
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/// Maps `HirId`s of variable bindings to the `Local`s created for them.
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/// (A match binding can have two locals; the 2nd is for the arm's guard.)
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var_indices: HirIdMap<LocalsForNode>,
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local_decls: IndexVec<Local, LocalDecl<'tcx>>,
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canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
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upvar_mutbls: Vec<Mutability>,
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unit_temp: Option<Place<'tcx>>,
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var_debug_info: Vec<VarDebugInfo<'tcx>>,
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/// Cached block with the `RESUME` terminator; this is created
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/// when first set of cleanups are built.
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cached_resume_block: Option<BasicBlock>,
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/// Cached block with the `RETURN` terminator.
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cached_return_block: Option<BasicBlock>,
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/// Cached block with the `UNREACHABLE` terminator.
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cached_unreachable_block: Option<BasicBlock>,
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}
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impl<'a, 'tcx> Builder<'a, 'tcx> {
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fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
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self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
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}
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fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
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self.var_indices[&id].local_id(for_guard)
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}
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}
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impl BlockContext {
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fn new() -> Self { BlockContext(vec![]) }
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fn push(&mut self, bf: BlockFrame) { self.0.push(bf); }
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fn pop(&mut self) -> Option<BlockFrame> { self.0.pop() }
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/// Traverses the frames on the `BlockContext`, searching for either
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/// the first block-tail expression frame with no intervening
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/// statement frame.
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///
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/// Notably, this skips over `SubExpr` frames; this method is
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/// meant to be used in the context of understanding the
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/// relationship of a temp (created within some complicated
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/// expression) with its containing expression, and whether the
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/// value of that *containing expression* (not the temp!) is
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/// ignored.
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fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
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for bf in self.0.iter().rev() {
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match bf {
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BlockFrame::SubExpr => continue,
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BlockFrame::Statement { .. } => break,
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&BlockFrame::TailExpr { tail_result_is_ignored } =>
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return Some(BlockTailInfo { tail_result_is_ignored })
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}
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}
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return None;
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}
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/// Looks at the topmost frame on the BlockContext and reports
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/// whether its one that would discard a block tail result.
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///
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/// Unlike `currently_within_ignored_tail_expression`, this does
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/// *not* skip over `SubExpr` frames: here, we want to know
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/// whether the block result itself is discarded.
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fn currently_ignores_tail_results(&self) -> bool {
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match self.0.last() {
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// no context: conservatively assume result is read
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None => false,
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// sub-expression: block result feeds into some computation
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Some(BlockFrame::SubExpr) => false,
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// otherwise: use accumulated is_ignored state.
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Some(BlockFrame::TailExpr { tail_result_is_ignored: ignored }) |
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Some(BlockFrame::Statement { ignores_expr_result: ignored }) => *ignored,
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}
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}
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}
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#[derive(Debug)]
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enum LocalsForNode {
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/// In the usual case, a `HirId` for an identifier maps to at most
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/// one `Local` declaration.
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One(Local),
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/// The exceptional case is identifiers in a match arm's pattern
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/// that are referenced in a guard of that match arm. For these,
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/// we have `2` Locals.
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///
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/// * `for_arm_body` is the Local used in the arm body (which is
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/// just like the `One` case above),
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///
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/// * `ref_for_guard` is the Local used in the arm's guard (which
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/// is a reference to a temp that is an alias of
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/// `for_arm_body`).
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ForGuard { ref_for_guard: Local, for_arm_body: Local },
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}
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#[derive(Debug)]
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struct GuardFrameLocal {
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id: hir::HirId,
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}
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impl GuardFrameLocal {
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fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
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GuardFrameLocal {
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id: id,
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}
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}
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}
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#[derive(Debug)]
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struct GuardFrame {
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/// These are the id's of names that are bound by patterns of the
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/// arm of *this* guard.
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///
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/// (Frames higher up the stack will have the id's bound in arms
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/// further out, such as in a case like:
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///
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/// match E1 {
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/// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
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/// }
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///
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/// here, when building for FIXME.
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locals: Vec<GuardFrameLocal>,
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}
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/// `ForGuard` indicates whether we are talking about:
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/// 1. The variable for use outside of guard expressions, or
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/// 2. The temp that holds reference to (1.), which is actually what the
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/// guard expressions see.
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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enum ForGuard {
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RefWithinGuard,
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OutsideGuard,
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}
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impl LocalsForNode {
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fn local_id(&self, for_guard: ForGuard) -> Local {
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match (self, for_guard) {
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(&LocalsForNode::One(local_id), ForGuard::OutsideGuard) |
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(&LocalsForNode::ForGuard { ref_for_guard: local_id, .. }, ForGuard::RefWithinGuard) |
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(&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) =>
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local_id,
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(&LocalsForNode::One(_), ForGuard::RefWithinGuard) =>
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bug!("anything with one local should never be within a guard."),
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}
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}
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}
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struct CFG<'tcx> {
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basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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}
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rustc_index::newtype_index! {
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pub struct ScopeId { .. }
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}
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///////////////////////////////////////////////////////////////////////////
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/// The `BlockAnd` "monad" packages up the new basic block along with a
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/// produced value (sometimes just unit, of course). The `unpack!`
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/// macro (and methods below) makes working with `BlockAnd` much more
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/// convenient.
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#[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
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struct BlockAnd<T>(BasicBlock, T);
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|
|
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
|
|
}
|
|
};
|
|
}
|
|
|
|
fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: DefId, _abi: Abi) -> bool {
|
|
// Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
|
|
let attrs = &tcx.get_attrs(fn_def_id);
|
|
let unwind_attr = attr::find_unwind_attr(Some(tcx.sess.diagnostic()), attrs);
|
|
|
|
// We never unwind, so it's not relevant to stop an unwind.
|
|
if tcx.sess.panic_strategy() != PanicStrategy::Unwind { return false; }
|
|
|
|
// We cannot add landing pads, so don't add one.
|
|
if tcx.sess.no_landing_pads() { return false; }
|
|
|
|
// This is a special case: some functions have a C abi but are meant to
|
|
// unwind anyway. Don't stop them.
|
|
match unwind_attr {
|
|
None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
|
|
Some(UnwindAttr::Allowed) => false,
|
|
Some(UnwindAttr::Aborts) => true,
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
/// the main entry point for building MIR for a function
|
|
|
|
struct ArgInfo<'tcx>(Ty<'tcx>, Option<Span>, Option<&'tcx hir::Param>, Option<ImplicitSelfKind>);
|
|
|
|
fn construct_fn<'a, 'tcx, A>(
|
|
hir: Cx<'a, 'tcx>,
|
|
fn_id: hir::HirId,
|
|
arguments: A,
|
|
safety: Safety,
|
|
abi: Abi,
|
|
return_ty: Ty<'tcx>,
|
|
return_ty_span: Span,
|
|
body: &'tcx hir::Body,
|
|
) -> Body<'tcx>
|
|
where
|
|
A: Iterator<Item=ArgInfo<'tcx>>
|
|
{
|
|
let arguments: Vec<_> = arguments.collect();
|
|
|
|
let tcx = hir.tcx();
|
|
let tcx_hir = tcx.hir();
|
|
let span = tcx_hir.span(fn_id);
|
|
|
|
let fn_def_id = tcx_hir.local_def_id(fn_id);
|
|
|
|
let mut builder = Builder::new(hir,
|
|
span,
|
|
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 mut block = START_BLOCK;
|
|
let source_info = builder.source_info(span);
|
|
let call_site_s = (call_site_scope, source_info);
|
|
unpack!(block = builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
|
|
if should_abort_on_panic(tcx, fn_def_id, abi) {
|
|
builder.schedule_abort();
|
|
}
|
|
|
|
let arg_scope_s = (arg_scope, source_info);
|
|
// `return_block` is called when we evaluate a `return` expression, so
|
|
// we just use `START_BLOCK` here.
|
|
unpack!(block = builder.in_breakable_scope(
|
|
None,
|
|
START_BLOCK,
|
|
Place::return_place(),
|
|
|builder| {
|
|
builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
|
|
builder.args_and_body(block, fn_def_id, &arguments, arg_scope, &body.value)
|
|
})
|
|
},
|
|
));
|
|
// Attribute epilogue to function's closing brace
|
|
let fn_end = span.shrink_to_hi();
|
|
let source_info = builder.source_info(fn_end);
|
|
let return_block = builder.return_block();
|
|
builder.cfg.terminate(block, source_info,
|
|
TerminatorKind::Goto { target: return_block });
|
|
builder.cfg.terminate(return_block, source_info,
|
|
TerminatorKind::Return);
|
|
// Attribute any unreachable codepaths to the function's closing brace
|
|
if let Some(unreachable_block) = builder.cached_unreachable_block {
|
|
builder.cfg.terminate(unreachable_block, source_info,
|
|
TerminatorKind::Unreachable);
|
|
}
|
|
return_block.unit()
|
|
}));
|
|
assert_eq!(block, builder.return_block());
|
|
|
|
let mut spread_arg = None;
|
|
if abi == Abi::RustCall {
|
|
// RustCall pseudo-ABI untuples the last argument.
|
|
spread_arg = Some(Local::new(arguments.len()));
|
|
}
|
|
info!("fn_id {:?} has attrs {:?}", fn_def_id,
|
|
tcx.get_attrs(fn_def_id));
|
|
|
|
let mut body = builder.finish();
|
|
body.spread_arg = spread_arg;
|
|
body
|
|
}
|
|
|
|
fn construct_const<'a, 'tcx>(
|
|
hir: Cx<'a, 'tcx>,
|
|
body_id: hir::BodyId,
|
|
const_ty: Ty<'tcx>,
|
|
const_ty_span: Span,
|
|
) -> Body<'tcx> {
|
|
let tcx = hir.tcx();
|
|
let owner_id = tcx.hir().body_owner(body_id);
|
|
let span = tcx.hir().span(owner_id);
|
|
let mut builder = Builder::new(
|
|
hir,
|
|
span,
|
|
0,
|
|
Safety::Safe,
|
|
const_ty,
|
|
const_ty_span,
|
|
None,
|
|
);
|
|
|
|
let mut block = START_BLOCK;
|
|
let ast_expr = &tcx.hir().body(body_id).value;
|
|
let expr = builder.hir.mirror(ast_expr);
|
|
unpack!(block = builder.into_expr(&Place::return_place(), block, expr));
|
|
|
|
let source_info = builder.source_info(span);
|
|
builder.cfg.terminate(block, source_info, TerminatorKind::Return);
|
|
|
|
// Constants can't `return` so a return block should not be created.
|
|
assert_eq!(builder.cached_return_block, None);
|
|
|
|
// Constants may be match expressions in which case an unreachable block may
|
|
// be created, so terminate it properly.
|
|
if let Some(unreachable_block) = builder.cached_unreachable_block {
|
|
builder.cfg.terminate(unreachable_block, source_info,
|
|
TerminatorKind::Unreachable);
|
|
}
|
|
|
|
builder.finish()
|
|
}
|
|
|
|
fn construct_error<'a, 'tcx>(
|
|
hir: Cx<'a, 'tcx>,
|
|
body_id: hir::BodyId
|
|
) -> Body<'tcx> {
|
|
let owner_id = hir.tcx().hir().body_owner(body_id);
|
|
let span = hir.tcx().hir().span(owner_id);
|
|
let ty = hir.tcx().types.err;
|
|
let mut builder = Builder::new(hir, span, 0, Safety::Safe, ty, span, None);
|
|
let source_info = builder.source_info(span);
|
|
builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
|
|
builder.finish()
|
|
}
|
|
|
|
impl<'a, 'tcx> Builder<'a, 'tcx> {
|
|
fn new(hir: Cx<'a, 'tcx>,
|
|
span: Span,
|
|
arg_count: usize,
|
|
safety: Safety,
|
|
return_ty: Ty<'tcx>,
|
|
return_span: Span,
|
|
generator_kind: Option<GeneratorKind>)
|
|
-> Builder<'a, 'tcx> {
|
|
let lint_level = LintLevel::Explicit(hir.root_lint_level);
|
|
let mut builder = Builder {
|
|
hir,
|
|
cfg: CFG { basic_blocks: IndexVec::new() },
|
|
fn_span: span,
|
|
arg_count,
|
|
generator_kind,
|
|
scopes: Default::default(),
|
|
block_context: BlockContext::new(),
|
|
source_scopes: IndexVec::new(),
|
|
source_scope: OUTERMOST_SOURCE_SCOPE,
|
|
source_scope_local_data: IndexVec::new(),
|
|
guard_context: vec![],
|
|
push_unsafe_count: 0,
|
|
unpushed_unsafe: safety,
|
|
local_decls: IndexVec::from_elem_n(
|
|
LocalDecl::new_return_place(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![],
|
|
cached_resume_block: None,
|
|
cached_return_block: None,
|
|
cached_unreachable_block: None,
|
|
};
|
|
|
|
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.cfg.basic_blocks,
|
|
self.source_scopes,
|
|
ClearCrossCrate::Set(self.source_scope_local_data),
|
|
self.local_decls,
|
|
self.canonical_user_type_annotations,
|
|
self.arg_count,
|
|
self.var_debug_info,
|
|
self.fn_span,
|
|
self.hir.control_flow_destroyed(),
|
|
self.generator_kind
|
|
)
|
|
}
|
|
|
|
fn args_and_body(&mut self,
|
|
mut block: BasicBlock,
|
|
fn_def_id: DefId,
|
|
arguments: &[ArgInfo<'tcx>],
|
|
argument_scope: region::Scope,
|
|
ast_body: &'tcx hir::Expr)
|
|
-> BlockAnd<()>
|
|
{
|
|
// Allocate locals for the function arguments
|
|
for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
|
|
let source_info = SourceInfo {
|
|
scope: OUTERMOST_SOURCE_SCOPE,
|
|
span: arg_opt.map_or(self.fn_span, |arg| arg.pat.span)
|
|
};
|
|
let arg_local = self.local_decls.push(LocalDecl {
|
|
mutability: Mutability::Mut,
|
|
ty,
|
|
user_ty: UserTypeProjections::none(),
|
|
source_info,
|
|
internal: false,
|
|
local_info: LocalInfo::Other,
|
|
is_block_tail: None,
|
|
});
|
|
|
|
// 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,
|
|
place: arg_local.into(),
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
let tcx = self.hir.tcx();
|
|
let tcx_hir = tcx.hir();
|
|
let hir_tables = self.hir.tables();
|
|
|
|
// In analyze_closure() in upvar.rs we gathered a list of upvars used by a
|
|
// closure and we stored in a map called upvar_list in TypeckTables indexed
|
|
// 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 let Some(upvars) = hir_tables.upvar_list.get(&fn_def_id) {
|
|
let closure_env_arg = Local::new(1);
|
|
let mut closure_env_projs = vec![];
|
|
let mut closure_ty = self.local_decls[closure_env_arg].ty;
|
|
if let ty::Ref(_, ty, _) = closure_ty.kind {
|
|
closure_env_projs.push(ProjectionElem::Deref);
|
|
closure_ty = ty;
|
|
}
|
|
let (def_id, upvar_substs) = match closure_ty.kind {
|
|
ty::Closure(def_id, substs) => (def_id, ty::UpvarSubsts::Closure(substs)),
|
|
ty::Generator(def_id, substs, _) => (def_id, ty::UpvarSubsts::Generator(substs)),
|
|
_ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty)
|
|
};
|
|
let upvar_tys = upvar_substs.upvar_tys(def_id, tcx);
|
|
let upvars_with_tys = upvars.iter().zip(upvar_tys);
|
|
self.upvar_mutbls = upvars_with_tys.enumerate().map(|(i, ((&var_id, &upvar_id), ty))| {
|
|
let capture = hir_tables.upvar_capture(upvar_id);
|
|
|
|
let mut mutability = Mutability::Not;
|
|
let mut name = kw::Invalid;
|
|
if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
|
|
if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
|
|
name = ident.name;
|
|
|
|
if let Some(&bm) = hir_tables.pat_binding_modes().get(pat.hir_id) {
|
|
if bm == ty::BindByValue(hir::Mutability::Mutable) {
|
|
mutability = Mutability::Mut;
|
|
} else {
|
|
mutability = Mutability::Not;
|
|
}
|
|
} else {
|
|
tcx.sess.delay_span_bug(pat.span, "missing binding mode");
|
|
}
|
|
}
|
|
}
|
|
|
|
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,
|
|
source_info: SourceInfo {
|
|
scope: OUTERMOST_SOURCE_SCOPE,
|
|
span: tcx_hir.span(var_id),
|
|
},
|
|
place: Place {
|
|
base: closure_env_arg.into(),
|
|
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(ast_body.span, |arg| arg.pat.span),
|
|
argument_scope, local, DropKind::Value,
|
|
);
|
|
|
|
if let Some(arg) = arg_opt {
|
|
let pattern = self.hir.pattern_from_hir(&arg.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 {
|
|
LocalInfo::User(ClearCrossCrate::Set(
|
|
BindingForm::ImplicitSelf(*kind),
|
|
))
|
|
} else {
|
|
let binding_mode = ty::BindingMode::BindByValue(mutability.into());
|
|
LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
|
|
VarBindingForm {
|
|
binding_mode,
|
|
opt_ty_info,
|
|
opt_match_place: Some((Some(place.clone()), span)),
|
|
pat_span: span,
|
|
},
|
|
)))
|
|
};
|
|
self.var_indices.insert(var, LocalsForNode::One(local));
|
|
}
|
|
_ => {
|
|
scope = self.declare_bindings(
|
|
scope,
|
|
ast_body.span,
|
|
&pattern,
|
|
matches::ArmHasGuard(false),
|
|
Some((Some(&place), span)),
|
|
);
|
|
unpack!(block = self.place_into_pattern(block, pattern, &place, 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;
|
|
}
|
|
|
|
let body = self.hir.mirror(ast_body);
|
|
self.into(&Place::return_place(), block, body)
|
|
}
|
|
|
|
fn set_correct_source_scope_for_arg(
|
|
&mut self,
|
|
arg_hir_id: hir::HirId,
|
|
original_source_scope: SourceScope,
|
|
pattern_span: Span
|
|
) {
|
|
let tcx = self.hir.tcx();
|
|
let current_root = tcx.maybe_lint_level_root_bounded(
|
|
arg_hir_id,
|
|
self.hir.root_lint_level
|
|
);
|
|
let parent_root = tcx.maybe_lint_level_root_bounded(
|
|
self.source_scope_local_data[original_source_scope].lint_root,
|
|
self.hir.root_lint_level,
|
|
);
|
|
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(ref tmp) => tmp.clone(),
|
|
None => {
|
|
let ty = self.hir.unit_ty();
|
|
let fn_span = self.fn_span;
|
|
let tmp = self.temp(ty, fn_span);
|
|
self.unit_temp = Some(tmp.clone());
|
|
tmp
|
|
}
|
|
}
|
|
}
|
|
|
|
fn return_block(&mut self) -> BasicBlock {
|
|
match self.cached_return_block {
|
|
Some(rb) => rb,
|
|
None => {
|
|
let rb = self.cfg.start_new_block();
|
|
self.cached_return_block = Some(rb);
|
|
rb
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
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///////////////////////////////////////////////////////////////////////////
|
|
// 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 into;
|
|
mod matches;
|
|
mod misc;
|
|
mod scope;
|