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Diffstat (limited to 'src/librustdoc/clean/utils.rs')
| -rw-r--r-- | src/librustdoc/clean/utils.rs | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs new file mode 100644 index 000000000..43e71e90a --- /dev/null +++ b/src/librustdoc/clean/utils.rs @@ -0,0 +1,616 @@ +use crate::clean::auto_trait::AutoTraitFinder; +use crate::clean::blanket_impl::BlanketImplFinder; +use crate::clean::render_macro_matchers::render_macro_matcher; +use crate::clean::{ + clean_middle_const, clean_middle_region, clean_middle_ty, inline, Clean, Crate, ExternalCrate, + Generic, GenericArg, GenericArgs, ImportSource, Item, ItemKind, Lifetime, Path, PathSegment, + Primitive, PrimitiveType, Type, TypeBinding, Visibility, +}; +use crate::core::DocContext; +use crate::formats::item_type::ItemType; +use crate::visit_lib::LibEmbargoVisitor; + +use rustc_ast as ast; +use rustc_ast::tokenstream::TokenTree; +use rustc_data_structures::thin_vec::ThinVec; +use rustc_hir as hir; +use rustc_hir::def::{DefKind, Res}; +use rustc_hir::def_id::{DefId, LOCAL_CRATE}; +use rustc_middle::mir; +use rustc_middle::mir::interpret::ConstValue; +use rustc_middle::ty::subst::{GenericArgKind, SubstsRef}; +use rustc_middle::ty::{self, DefIdTree, TyCtxt}; +use rustc_span::symbol::{kw, sym, Symbol}; +use std::fmt::Write as _; +use std::mem; + +#[cfg(test)] +mod tests; + +pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate { + let module = crate::visit_ast::RustdocVisitor::new(cx).visit(); + + for &cnum in cx.tcx.crates(()) { + // Analyze doc-reachability for extern items + LibEmbargoVisitor::new(cx).visit_lib(cnum); + } + + // Clean the crate, translating the entire librustc_ast AST to one that is + // understood by rustdoc. + let mut module = module.clean(cx); + + match *module.kind { + ItemKind::ModuleItem(ref module) => { + for it in &module.items { + // `compiler_builtins` should be masked too, but we can't apply + // `#[doc(masked)]` to the injected `extern crate` because it's unstable. + if it.is_extern_crate() + && (it.attrs.has_doc_flag(sym::masked) + || cx.tcx.is_compiler_builtins(it.item_id.krate())) + { + cx.cache.masked_crates.insert(it.item_id.krate()); + } + } + } + _ => unreachable!(), + } + + let local_crate = ExternalCrate { crate_num: LOCAL_CRATE }; + let primitives = local_crate.primitives(cx.tcx); + let keywords = local_crate.keywords(cx.tcx); + { + let ItemKind::ModuleItem(ref mut m) = *module.kind + else { unreachable!() }; + m.items.extend(primitives.iter().map(|&(def_id, prim)| { + Item::from_def_id_and_parts( + def_id, + Some(prim.as_sym()), + ItemKind::PrimitiveItem(prim), + cx, + ) + })); + m.items.extend(keywords.into_iter().map(|(def_id, kw)| { + Item::from_def_id_and_parts(def_id, Some(kw), ItemKind::KeywordItem, cx) + })); + } + + Crate { module, primitives, external_traits: cx.external_traits.clone() } +} + +pub(crate) fn substs_to_args<'tcx>( + cx: &mut DocContext<'tcx>, + substs: &[ty::subst::GenericArg<'tcx>], + mut skip_first: bool, +) -> Vec<GenericArg> { + let mut ret_val = + Vec::with_capacity(substs.len().saturating_sub(if skip_first { 1 } else { 0 })); + ret_val.extend(substs.iter().filter_map(|kind| match kind.unpack() { + GenericArgKind::Lifetime(lt) => { + Some(GenericArg::Lifetime(clean_middle_region(lt).unwrap_or(Lifetime::elided()))) + } + GenericArgKind::Type(_) if skip_first => { + skip_first = false; + None + } + GenericArgKind::Type(ty) => Some(GenericArg::Type(clean_middle_ty(ty, cx, None))), + GenericArgKind::Const(ct) => Some(GenericArg::Const(Box::new(clean_middle_const(ct, cx)))), + })); + ret_val +} + +fn external_generic_args<'tcx>( + cx: &mut DocContext<'tcx>, + did: DefId, + has_self: bool, + bindings: Vec<TypeBinding>, + substs: SubstsRef<'tcx>, +) -> GenericArgs { + let args = substs_to_args(cx, substs, has_self); + + if cx.tcx.fn_trait_kind_from_lang_item(did).is_some() { + let inputs = + // The trait's first substitution is the one after self, if there is one. + match substs.iter().nth(if has_self { 1 } else { 0 }).unwrap().expect_ty().kind() { + ty::Tuple(tys) => tys.iter().map(|t| clean_middle_ty(t, cx, None)).collect::<Vec<_>>().into(), + _ => return GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() }, + }; + let output = None; + // FIXME(#20299) return type comes from a projection now + // match types[1].kind { + // ty::Tuple(ref v) if v.is_empty() => None, // -> () + // _ => Some(types[1].clean(cx)) + // }; + GenericArgs::Parenthesized { inputs, output } + } else { + GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() } + } +} + +pub(super) fn external_path<'tcx>( + cx: &mut DocContext<'tcx>, + did: DefId, + has_self: bool, + bindings: Vec<TypeBinding>, + substs: SubstsRef<'tcx>, +) -> Path { + let def_kind = cx.tcx.def_kind(did); + let name = cx.tcx.item_name(did); + Path { + res: Res::Def(def_kind, did), + segments: vec![PathSegment { + name, + args: external_generic_args(cx, did, has_self, bindings, substs), + }], + } +} + +/// Remove the generic arguments from a path. +pub(crate) fn strip_path_generics(mut path: Path) -> Path { + for ps in path.segments.iter_mut() { + ps.args = GenericArgs::AngleBracketed { args: Default::default(), bindings: ThinVec::new() } + } + + path +} + +pub(crate) fn qpath_to_string(p: &hir::QPath<'_>) -> String { + let segments = match *p { + hir::QPath::Resolved(_, path) => &path.segments, + hir::QPath::TypeRelative(_, segment) => return segment.ident.to_string(), + hir::QPath::LangItem(lang_item, ..) => return lang_item.name().to_string(), + }; + + let mut s = String::new(); + for (i, seg) in segments.iter().enumerate() { + if i > 0 { + s.push_str("::"); + } + if seg.ident.name != kw::PathRoot { + s.push_str(seg.ident.as_str()); + } + } + s +} + +pub(crate) fn build_deref_target_impls( + cx: &mut DocContext<'_>, + items: &[Item], + ret: &mut Vec<Item>, +) { + let tcx = cx.tcx; + + for item in items { + let target = match *item.kind { + ItemKind::AssocTypeItem(ref t, _) => &t.type_, + _ => continue, + }; + + if let Some(prim) = target.primitive_type() { + let _prof_timer = cx.tcx.sess.prof.generic_activity("build_primitive_inherent_impls"); + for did in prim.impls(tcx).filter(|did| !did.is_local()) { + inline::build_impl(cx, None, did, None, ret); + } + } else if let Type::Path { path } = target { + let did = path.def_id(); + if !did.is_local() { + inline::build_impls(cx, None, did, None, ret); + } + } + } +} + +pub(crate) fn name_from_pat(p: &hir::Pat<'_>) -> Symbol { + use rustc_hir::*; + debug!("trying to get a name from pattern: {:?}", p); + + Symbol::intern(&match p.kind { + PatKind::Wild | PatKind::Struct(..) => return kw::Underscore, + PatKind::Binding(_, _, ident, _) => return ident.name, + PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p), + PatKind::Or(pats) => { + pats.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(" | ") + } + PatKind::Tuple(elts, _) => format!( + "({})", + elts.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(", ") + ), + PatKind::Box(p) => return name_from_pat(&*p), + PatKind::Ref(p, _) => return name_from_pat(&*p), + PatKind::Lit(..) => { + warn!( + "tried to get argument name from PatKind::Lit, which is silly in function arguments" + ); + return Symbol::intern("()"); + } + PatKind::Range(..) => return kw::Underscore, + PatKind::Slice(begin, ref mid, end) => { + let begin = begin.iter().map(|p| name_from_pat(p).to_string()); + let mid = mid.as_ref().map(|p| format!("..{}", name_from_pat(&**p))).into_iter(); + let end = end.iter().map(|p| name_from_pat(p).to_string()); + format!("[{}]", begin.chain(mid).chain(end).collect::<Vec<_>>().join(", ")) + } + }) +} + +pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String { + match n.kind() { + ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) => { + let mut s = if let Some(def) = def.as_local() { + print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(def.did)) + } else { + inline::print_inlined_const(cx.tcx, def.did) + }; + if let Some(promoted) = promoted { + s.push_str(&format!("::{:?}", promoted)) + } + s + } + _ => { + let mut s = n.to_string(); + // array lengths are obviously usize + if s.ends_with("_usize") { + let n = s.len() - "_usize".len(); + s.truncate(n); + if s.ends_with(": ") { + let n = s.len() - ": ".len(); + s.truncate(n); + } + } + s + } + } +} + +pub(crate) fn print_evaluated_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<String> { + tcx.const_eval_poly(def_id).ok().and_then(|val| { + let ty = tcx.type_of(def_id); + match (val, ty.kind()) { + (_, &ty::Ref(..)) => None, + (ConstValue::Scalar(_), &ty::Adt(_, _)) => None, + (ConstValue::Scalar(_), _) => { + let const_ = mir::ConstantKind::from_value(val, ty); + Some(print_const_with_custom_print_scalar(tcx, const_)) + } + _ => None, + } + }) +} + +fn format_integer_with_underscore_sep(num: &str) -> String { + let num_chars: Vec<_> = num.chars().collect(); + let mut num_start_index = if num_chars.get(0) == Some(&'-') { 1 } else { 0 }; + let chunk_size = match num[num_start_index..].as_bytes() { + [b'0', b'b' | b'x', ..] => { + num_start_index += 2; + 4 + } + [b'0', b'o', ..] => { + num_start_index += 2; + let remaining_chars = num_chars.len() - num_start_index; + if remaining_chars <= 6 { + // don't add underscores to Unix permissions like 0755 or 100755 + return num.to_string(); + } + 3 + } + _ => 3, + }; + + num_chars[..num_start_index] + .iter() + .chain(num_chars[num_start_index..].rchunks(chunk_size).rev().intersperse(&['_']).flatten()) + .collect() +} + +fn print_const_with_custom_print_scalar(tcx: TyCtxt<'_>, ct: mir::ConstantKind<'_>) -> String { + // Use a slightly different format for integer types which always shows the actual value. + // For all other types, fallback to the original `pretty_print_const`. + match (ct, ct.ty().kind()) { + (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Uint(ui)) => { + format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str()) + } + (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Int(i)) => { + let ty = tcx.lift(ct.ty()).unwrap(); + let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size; + let data = int.assert_bits(size); + let sign_extended_data = size.sign_extend(data) as i128; + format!( + "{}{}", + format_integer_with_underscore_sep(&sign_extended_data.to_string()), + i.name_str() + ) + } + _ => ct.to_string(), + } +} + +pub(crate) fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool { + if let hir::Node::Expr(expr) = tcx.hir().get(hir_id) { + if let hir::ExprKind::Lit(_) = &expr.kind { + return true; + } + + if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind { + if let hir::ExprKind::Lit(_) = &expr.kind { + return true; + } + } + } + + false +} + +/// Build a textual representation of an unevaluated constant expression. +/// +/// If the const expression is too complex, an underscore `_` is returned. +/// For const arguments, it's `{ _ }` to be precise. +/// This means that the output is not necessarily valid Rust code. +/// +/// Currently, only +/// +/// * literals (optionally with a leading `-`) +/// * unit `()` +/// * blocks (`{ … }`) around simple expressions and +/// * paths without arguments +/// +/// are considered simple enough. Simple blocks are included since they are +/// necessary to disambiguate unit from the unit type. +/// This list might get extended in the future. +/// +/// Without this censoring, in a lot of cases the output would get too large +/// and verbose. Consider `match` expressions, blocks and deeply nested ADTs. +/// Further, private and `doc(hidden)` fields of structs would get leaked +/// since HIR datatypes like the `body` parameter do not contain enough +/// semantic information for this function to be able to hide them – +/// at least not without significant performance overhead. +/// +/// Whenever possible, prefer to evaluate the constant first and try to +/// use a different method for pretty-printing. Ideally this function +/// should only ever be used as a fallback. +pub(crate) fn print_const_expr(tcx: TyCtxt<'_>, body: hir::BodyId) -> String { + let hir = tcx.hir(); + let value = &hir.body(body).value; + + #[derive(PartialEq, Eq)] + enum Classification { + Literal, + Simple, + Complex, + } + + use Classification::*; + + fn classify(expr: &hir::Expr<'_>) -> Classification { + match &expr.kind { + hir::ExprKind::Unary(hir::UnOp::Neg, expr) => { + if matches!(expr.kind, hir::ExprKind::Lit(_)) { Literal } else { Complex } + } + hir::ExprKind::Lit(_) => Literal, + hir::ExprKind::Tup([]) => Simple, + hir::ExprKind::Block(hir::Block { stmts: [], expr: Some(expr), .. }, _) => { + if classify(expr) == Complex { Complex } else { Simple } + } + // Paths with a self-type or arguments are too “complex” following our measure since + // they may leak private fields of structs (with feature `adt_const_params`). + // Consider: `<Self as Trait<{ Struct { private: () } }>>::CONSTANT`. + // Paths without arguments are definitely harmless though. + hir::ExprKind::Path(hir::QPath::Resolved(_, hir::Path { segments, .. })) => { + if segments.iter().all(|segment| segment.args.is_none()) { Simple } else { Complex } + } + // FIXME: Claiming that those kinds of QPaths are simple is probably not true if the Ty + // contains const arguments. Is there a *concise* way to check for this? + hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => Simple, + // FIXME: Can they contain const arguments and thus leak private struct fields? + hir::ExprKind::Path(hir::QPath::LangItem(..)) => Simple, + _ => Complex, + } + } + + let classification = classify(value); + + if classification == Literal + && !value.span.from_expansion() + && let Ok(snippet) = tcx.sess.source_map().span_to_snippet(value.span) { + // For literals, we avoid invoking the pretty-printer and use the source snippet instead to + // preserve certain stylistic choices the user likely made for the sake legibility like + // + // * hexadecimal notation + // * underscores + // * character escapes + // + // FIXME: This passes through `-/*spacer*/0` verbatim. + snippet + } else if classification == Simple { + // Otherwise we prefer pretty-printing to get rid of extraneous whitespace, comments and + // other formatting artifacts. + rustc_hir_pretty::id_to_string(&hir, body.hir_id) + } else if tcx.def_kind(hir.body_owner_def_id(body).to_def_id()) == DefKind::AnonConst { + // FIXME: Omit the curly braces if the enclosing expression is an array literal + // with a repeated element (an `ExprKind::Repeat`) as in such case it + // would not actually need any disambiguation. + "{ _ }".to_owned() + } else { + "_".to_owned() + } +} + +/// Given a type Path, resolve it to a Type using the TyCtxt +pub(crate) fn resolve_type(cx: &mut DocContext<'_>, path: Path) -> Type { + debug!("resolve_type({:?})", path); + + match path.res { + Res::PrimTy(p) => Primitive(PrimitiveType::from(p)), + Res::SelfTy { .. } if path.segments.len() == 1 => Generic(kw::SelfUpper), + Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => Generic(path.segments[0].name), + _ => { + let _ = register_res(cx, path.res); + Type::Path { path } + } + } +} + +pub(crate) fn get_auto_trait_and_blanket_impls( + cx: &mut DocContext<'_>, + item_def_id: DefId, +) -> impl Iterator<Item = Item> { + let auto_impls = cx + .sess() + .prof + .generic_activity("get_auto_trait_impls") + .run(|| AutoTraitFinder::new(cx).get_auto_trait_impls(item_def_id)); + let blanket_impls = cx + .sess() + .prof + .generic_activity("get_blanket_impls") + .run(|| BlanketImplFinder { cx }.get_blanket_impls(item_def_id)); + auto_impls.into_iter().chain(blanket_impls) +} + +/// If `res` has a documentation page associated, store it in the cache. +/// +/// This is later used by [`href()`] to determine the HTML link for the item. +/// +/// [`href()`]: crate::html::format::href +pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId { + use DefKind::*; + debug!("register_res({:?})", res); + + let (did, kind) = match res { + // These should be added to the cache using `record_extern_fqn`. + Res::Def( + kind @ (AssocTy | AssocFn | AssocConst | Variant | Fn | TyAlias | Enum | Trait | Struct + | Union | Mod | ForeignTy | Const | Static(_) | Macro(..) | TraitAlias), + i, + ) => (i, kind.into()), + // This is part of a trait definition or trait impl; document the trait. + Res::SelfTy { trait_: Some(trait_def_id), alias_to: _ } => (trait_def_id, ItemType::Trait), + // This is an inherent impl or a type definition; it doesn't have its own page. + Res::SelfTy { trait_: None, alias_to: Some((item_def_id, _)) } => return item_def_id, + Res::SelfTy { trait_: None, alias_to: None } + | Res::PrimTy(_) + | Res::ToolMod + | Res::SelfCtor(_) + | Res::Local(_) + | Res::NonMacroAttr(_) + | Res::Err => return res.def_id(), + Res::Def( + TyParam | ConstParam | Ctor(..) | ExternCrate | Use | ForeignMod | AnonConst + | InlineConst | OpaqueTy | Field | LifetimeParam | GlobalAsm | Impl | Closure + | Generator, + id, + ) => return id, + }; + if did.is_local() { + return did; + } + inline::record_extern_fqn(cx, did, kind); + if let ItemType::Trait = kind { + inline::record_extern_trait(cx, did); + } + did +} + +pub(crate) fn resolve_use_source(cx: &mut DocContext<'_>, path: Path) -> ImportSource { + ImportSource { + did: if path.res.opt_def_id().is_none() { None } else { Some(register_res(cx, path.res)) }, + path, + } +} + +pub(crate) fn enter_impl_trait<'tcx, F, R>(cx: &mut DocContext<'tcx>, f: F) -> R +where + F: FnOnce(&mut DocContext<'tcx>) -> R, +{ + let old_bounds = mem::take(&mut cx.impl_trait_bounds); + let r = f(cx); + assert!(cx.impl_trait_bounds.is_empty()); + cx.impl_trait_bounds = old_bounds; + r +} + +/// Find the nearest parent module of a [`DefId`]. +pub(crate) fn find_nearest_parent_module(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> { + if def_id.is_top_level_module() { + // The crate root has no parent. Use it as the root instead. + Some(def_id) + } else { + let mut current = def_id; + // The immediate parent might not always be a module. + // Find the first parent which is. + while let Some(parent) = tcx.opt_parent(current) { + if tcx.def_kind(parent) == DefKind::Mod { + return Some(parent); + } + current = parent; + } + None + } +} + +/// Checks for the existence of `hidden` in the attribute below if `flag` is `sym::hidden`: +/// +/// ``` +/// #[doc(hidden)] +/// pub fn foo() {} +/// ``` +/// +/// This function exists because it runs on `hir::Attributes` whereas the other is a +/// `clean::Attributes` method. +pub(crate) fn has_doc_flag(tcx: TyCtxt<'_>, did: DefId, flag: Symbol) -> bool { + tcx.get_attrs(did, sym::doc).any(|attr| { + attr.meta_item_list().map_or(false, |l| rustc_attr::list_contains_name(&l, flag)) + }) +} + +/// A link to `doc.rust-lang.org` that includes the channel name. Use this instead of manual links +/// so that the channel is consistent. +/// +/// Set by `bootstrap::Builder::doc_rust_lang_org_channel` in order to keep tests passing on beta/stable. +pub(crate) const DOC_RUST_LANG_ORG_CHANNEL: &str = env!("DOC_RUST_LANG_ORG_CHANNEL"); + +/// Render a sequence of macro arms in a format suitable for displaying to the user +/// as part of an item declaration. +pub(super) fn render_macro_arms<'a>( + tcx: TyCtxt<'_>, + matchers: impl Iterator<Item = &'a TokenTree>, + arm_delim: &str, +) -> String { + let mut out = String::new(); + for matcher in matchers { + writeln!(out, " {} => {{ ... }}{}", render_macro_matcher(tcx, matcher), arm_delim) + .unwrap(); + } + out +} + +pub(super) fn display_macro_source( + cx: &mut DocContext<'_>, + name: Symbol, + def: &ast::MacroDef, + def_id: DefId, + vis: Visibility, +) -> String { + let tts: Vec<_> = def.body.inner_tokens().into_trees().collect(); + // Extract the spans of all matchers. They represent the "interface" of the macro. + let matchers = tts.chunks(4).map(|arm| &arm[0]); + + if def.macro_rules { + format!("macro_rules! {} {{\n{}}}", name, render_macro_arms(cx.tcx, matchers, ";")) + } else { + if matchers.len() <= 1 { + format!( + "{}macro {}{} {{\n ...\n}}", + vis.to_src_with_space(cx.tcx, def_id), + name, + matchers.map(|matcher| render_macro_matcher(cx.tcx, matcher)).collect::<String>(), + ) + } else { + format!( + "{}macro {} {{\n{}}}", + vis.to_src_with_space(cx.tcx, def_id), + name, + render_macro_arms(cx.tcx, matchers, ","), + ) + } + } +} |