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resolve: Further simplify legacy scopes, add comments

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This commit is contained in:
Vadim Petrochenkov 2018-08-31 22:53:08 +03:00
parent e00993a1ab
commit ae2e5aa1c7
2 changed files with 45 additions and 40 deletions
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5
src/librustc_resolve/build_reduced_graph.rs
View file

@ -961,6 +961,7 @@ impl<'a, 'b, 'cl> BuildReducedGraphVisitor<'a, 'b, 'cl> {
let invocation = self.resolver.invocations[&mark]; let invocation = self.resolver.invocations[&mark];
invocation.module.set(self.resolver.current_module); invocation.module.set(self.resolver.current_module);
invocation.parent_legacy_scope.set(self.current_legacy_scope); invocation.parent_legacy_scope.set(self.current_legacy_scope);
invocation.output_legacy_scope.set(self.current_legacy_scope);
invocation invocation
} }
} }
@ -990,7 +991,7 @@ impl<'a, 'b, 'cl> Visitor<'a> for BuildReducedGraphVisitor<'a, 'b, 'cl> {
return return
} }
ItemKind::Mac(..) => { ItemKind::Mac(..) => {
self.current_legacy_scope = LegacyScope::Expansion(self.visit_invoc(item.id)); self.current_legacy_scope = LegacyScope::Invocation(self.visit_invoc(item.id));
return return
} }
ItemKind::Mod(..) => self.resolver.contains_macro_use(&item.attrs), ItemKind::Mod(..) => self.resolver.contains_macro_use(&item.attrs),
@ -1009,7 +1010,7 @@ impl<'a, 'b, 'cl> Visitor<'a> for BuildReducedGraphVisitor<'a, 'b, 'cl> {
fn visit_stmt(&mut self, stmt: &'a ast::Stmt) { fn visit_stmt(&mut self, stmt: &'a ast::Stmt) {
if let ast::StmtKind::Mac(..) = stmt.node { if let ast::StmtKind::Mac(..) = stmt.node {
self.current_legacy_scope = LegacyScope::Expansion(self.visit_invoc(stmt.id)); self.current_legacy_scope = LegacyScope::Invocation(self.visit_invoc(stmt.id));
} else { } else {
visit::walk_stmt(self, stmt); visit::walk_stmt(self, stmt);
} }

80
src/librustc_resolve/macros.rs
View file

@ -50,15 +50,16 @@ crate struct FromPrelude(bool);
#[derive(Clone)] #[derive(Clone)]
pub struct InvocationData<'a> { pub struct InvocationData<'a> {
crate module: Cell<Module<'a>>,
def_index: DefIndex, def_index: DefIndex,
// Legacy scope in which the macro was invoked. /// Module in which the macro was invoked.
// The invocation path is resolved in this scope. crate module: Cell<Module<'a>>,
/// Legacy scope in which the macro was invoked.
/// The invocation path is resolved in this scope.
crate parent_legacy_scope: Cell<LegacyScope<'a>>, crate parent_legacy_scope: Cell<LegacyScope<'a>>,
// Legacy scope *produced* by expanding this macro invocation, /// Legacy scope *produced* by expanding this macro invocation,
// includes all the macro_rules items, other invocations, etc generated by it. /// includes all the macro_rules items, other invocations, etc generated by it.
// `Empty` is used if for invocations that has not been expanded yet. /// Set to the parent scope if the macro is not expanded yet (as if the macro produced nothing).
output_legacy_scope: Cell<LegacyScope<'a>>, crate output_legacy_scope: Cell<LegacyScope<'a>>,
} }
impl<'a> InvocationData<'a> { impl<'a> InvocationData<'a> {
@ -72,21 +73,32 @@ impl<'a> InvocationData<'a> {
} }
} }
// Binding produced by a `macro_rules` item. /// Binding produced by a `macro_rules` item.
// Not modularized, can shadow previous legacy bindings, etc. /// Not modularized, can shadow previous legacy bindings, etc.
pub struct LegacyBinding<'a> { pub struct LegacyBinding<'a> {
binding: &'a NameBinding<'a>, binding: &'a NameBinding<'a>,
// Legacy scope into which the `macro_rules` item was planted. /// Legacy scope into which the `macro_rules` item was planted.
parent_legacy_scope: Cell<LegacyScope<'a>>, parent_legacy_scope: LegacyScope<'a>,
ident: Ident, ident: Ident,
} }
/// Scope introduced by a `macro_rules!` macro.
/// Starts at the macro's definition and ends at the end of the macro's parent module
/// (named or unnamed), or even further if it escapes with `#[macro_use]`.
/// Some macro invocations need to introduce legacy scopes too because they
/// potentially can expand into macro definitions.
#[derive(Copy, Clone)] #[derive(Copy, Clone)]
pub enum LegacyScope<'a> { pub enum LegacyScope<'a> {
/// Created when invocation data is allocated in the arena,
/// must be replaced with a proper scope later.
Uninitialized,
/// Empty "root" scope at the crate start containing no names.
Empty, Empty,
Invocation(&'a InvocationData<'a>), // The scope of the invocation, not including its expansion /// Scope introduced by a `macro_rules!` macro definition.
Expansion(&'a InvocationData<'a>), // The scope of the invocation, including its expansion
Binding(&'a LegacyBinding<'a>), Binding(&'a LegacyBinding<'a>),
/// Scope introduced by a macro invocation that can potentially
/// create a `macro_rules!` macro definition.
Invocation(&'a InvocationData<'a>),
} }
pub struct ProcMacError { pub struct ProcMacError {
@ -181,7 +193,7 @@ impl<'a, 'crateloader: 'a> base::Resolver for Resolver<'a, 'crateloader> {
} }
let mut visitor = BuildReducedGraphVisitor { let mut visitor = BuildReducedGraphVisitor {
resolver: self, resolver: self,
current_legacy_scope: LegacyScope::Invocation(invocation), current_legacy_scope: invocation.parent_legacy_scope.get(),
expansion: mark, expansion: mark,
}; };
fragment.visit_with(&mut visitor); fragment.visit_with(&mut visitor);
@ -483,8 +495,9 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
} }
} }
let legacy_resolution = let legacy_resolution = self.resolve_legacy_scope(
self.resolve_legacy_scope(path[0], invoc_id, &invocation.parent_legacy_scope, false); path[0], invoc_id, invocation.parent_legacy_scope.get(), false
);
let result = if let Some(legacy_binding) = legacy_resolution { let result = if let Some(legacy_binding) = legacy_resolution {
Ok(legacy_binding.def()) Ok(legacy_binding.def())
} else { } else {
@ -788,7 +801,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
fn resolve_legacy_scope(&mut self, fn resolve_legacy_scope(&mut self,
ident: Ident, ident: Ident,
invoc_id: Mark, invoc_id: Mark,
invoc_parent_legacy_scope: &'a Cell<LegacyScope<'a>>, invoc_parent_legacy_scope: LegacyScope<'a>,
record_used: bool) record_used: bool)
-> Option<&'a NameBinding<'a>> { -> Option<&'a NameBinding<'a>> {
let ident = ident.modern(); let ident = ident.modern();
@ -809,28 +822,18 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
// Go through all the scopes and try to resolve the name. // Go through all the scopes and try to resolve the name.
let mut where_to_resolve = invoc_parent_legacy_scope; let mut where_to_resolve = invoc_parent_legacy_scope;
loop { loop {
let result = match where_to_resolve.get() { let result = match where_to_resolve {
LegacyScope::Binding(legacy_binding) if ident == legacy_binding.ident => LegacyScope::Binding(legacy_binding) if ident == legacy_binding.ident =>
Some(legacy_binding.binding), Some(legacy_binding.binding),
_ => None, _ => None,
}; };
macro_rules! continue_search { () => { macro_rules! continue_search { () => {
where_to_resolve = match where_to_resolve.get() { where_to_resolve = match where_to_resolve {
LegacyScope::Empty => break, // nowhere else to search LegacyScope::Empty => break, // nowhere else to search
LegacyScope::Binding(binding) => &binding.parent_legacy_scope, LegacyScope::Binding(binding) => binding.parent_legacy_scope,
LegacyScope::Invocation(invocation) => &invocation.parent_legacy_scope, LegacyScope::Invocation(invocation) => invocation.output_legacy_scope.get(),
LegacyScope::Expansion(invocation) => { LegacyScope::Uninitialized => unreachable!(),
match invocation.output_legacy_scope.get() {
LegacyScope::Empty => &invocation.parent_legacy_scope,
LegacyScope::Binding(..) |
LegacyScope::Expansion(..) => &invocation.output_legacy_scope,
LegacyScope::Invocation(..) => {
where_to_resolve.set(invocation.parent_legacy_scope.get());
where_to_resolve
}
}
}
}; };
continue; continue;
@ -885,9 +888,10 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
for &(invoc_id, ident, kind, def) in module.legacy_macro_resolutions.borrow().iter() { for &(invoc_id, ident, kind, def) in module.legacy_macro_resolutions.borrow().iter() {
let span = ident.span; let span = ident.span;
let invoc_parent_legacy_scope = &self.invocations[&invoc_id].parent_legacy_scope; let invocation = self.invocations[&invoc_id];
let legacy_resolution = let legacy_resolution = self.resolve_legacy_scope(
self.resolve_legacy_scope(ident, invoc_id, invoc_parent_legacy_scope, true); ident, invoc_id, invocation.parent_legacy_scope.get(), true
);
let resolution = self.resolve_lexical_macro_path_segment( let resolution = self.resolve_lexical_macro_path_segment(
ident, MacroNS, invoc_id, true, true, kind == MacroKind::Attr, span ident, MacroNS, invoc_id, true, true, kind == MacroKind::Attr, span
); );
@ -1013,8 +1017,8 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
arenas.alloc_invocation_data(InvocationData { arenas.alloc_invocation_data(InvocationData {
def_index: invoc.def_index, def_index: invoc.def_index,
module: Cell::new(graph_root), module: Cell::new(graph_root),
parent_legacy_scope: Cell::new(LegacyScope::Empty), parent_legacy_scope: Cell::new(LegacyScope::Uninitialized),
output_legacy_scope: Cell::new(LegacyScope::Empty), output_legacy_scope: Cell::new(LegacyScope::Uninitialized),
}) })
}); });
}; };
@ -1050,7 +1054,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
let vis = ty::Visibility::Invisible; // Doesn't matter for legacy bindings let vis = ty::Visibility::Invisible; // Doesn't matter for legacy bindings
let binding = (def, vis, item.span, expansion).to_name_binding(self.arenas); let binding = (def, vis, item.span, expansion).to_name_binding(self.arenas);
let legacy_binding = self.arenas.alloc_legacy_binding(LegacyBinding { let legacy_binding = self.arenas.alloc_legacy_binding(LegacyBinding {
parent_legacy_scope: Cell::new(*current_legacy_scope), binding, ident parent_legacy_scope: *current_legacy_scope, binding, ident
}); });
*current_legacy_scope = LegacyScope::Binding(legacy_binding); *current_legacy_scope = LegacyScope::Binding(legacy_binding);
self.all_macros.insert(ident.name, def); self.all_macros.insert(ident.name, def);