Expansion-driven outline module parsing

src/libpanic_unwind/emcc.rs

@@ -6,8 +6,6 @@
 //! Emscripten's runtime always implements those APIs and does not
 //! implement libunwind.
 
-#![allow(private_no_mangle_fns)]
-
 use alloc::boxed::Box;
 use core::any::Any;
 use core::mem;

src/libpanic_unwind/gcc.rs

@@ -36,8 +36,6 @@
 //! Once stack has been unwound down to the handler frame level, unwinding stops
 //! and the last personality routine transfers control to the catch block.
 
-#![allow(private_no_mangle_fns)]
-
 use alloc::boxed::Box;
 use core::any::Any;
 

src/libpanic_unwind/seh.rs

@@ -45,7 +45,6 @@
 //! [llvm]: http://llvm.org/docs/ExceptionHandling.html#background-on-windows-exceptions
 
 #![allow(nonstandard_style)]
-#![allow(private_no_mangle_fns)]
 
 use alloc::boxed::Box;
 use core::any::Any;

src/librustc_ast/ast.rs

@@ -2153,7 +2153,7 @@ impl FnRetTy {
 /// Module declaration.
 ///
 /// E.g., `mod foo;` or `mod foo { .. }`.
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Default)]
 pub struct Mod {
     /// A span from the first token past `{` to the last token until `}`.
     /// For `mod foo;`, the inner span ranges from the first token

src/librustc_builtin_macros/proc_macro_harness.rs

@@ -59,7 +59,7 @@ pub fn inject(
     handler: &rustc_errors::Handler,
 ) -> ast::Crate {
     let ecfg = ExpansionConfig::default("proc_macro".to_string());
-    let mut cx = ExtCtxt::new(sess, ecfg, resolver);
+    let mut cx = ExtCtxt::new(sess, ecfg, resolver, None);
 
     let mut collect = CollectProcMacros {
         macros: Vec::new(),

src/librustc_builtin_macros/source_util.rs

@@ -5,7 +5,7 @@ use rustc_ast::tokenstream::TokenStream;
 use rustc_ast_pretty::pprust;
 use rustc_expand::base::{self, *};
 use rustc_expand::panictry;
-use rustc_parse::{self, new_sub_parser_from_file, parser::Parser, DirectoryOwnership};
+use rustc_parse::{self, new_sub_parser_from_file, parser::Parser};
 use rustc_session::lint::builtin::INCOMPLETE_INCLUDE;
 use rustc_span::symbol::Symbol;
 use rustc_span::{self, Pos, Span};
@@ -108,8 +108,7 @@ pub fn expand_include<'cx>(
             return DummyResult::any(sp);
         }
     };
-    let directory_ownership = DirectoryOwnership::Owned { relative: None };
-    let p = new_sub_parser_from_file(cx.parse_sess(), &file, directory_ownership, None, sp);
+    let p = new_sub_parser_from_file(cx.parse_sess(), &file, None, sp);
 
     struct ExpandResult<'a> {
         p: Parser<'a>,

src/librustc_builtin_macros/standard_library_imports.rs

@@ -39,7 +39,7 @@ pub fn inject(
     let call_site = DUMMY_SP.with_call_site_ctxt(expn_id);
 
     let ecfg = ExpansionConfig::default("std_lib_injection".to_string());
-    let cx = ExtCtxt::new(sess, ecfg, resolver);
+    let cx = ExtCtxt::new(sess, ecfg, resolver, None);
 
     // .rev() to preserve ordering above in combination with insert(0, ...)
     for &name in names.iter().rev() {

src/librustc_builtin_macros/test_harness.rs

@@ -202,7 +202,7 @@ fn generate_test_harness(
     let mut econfig = ExpansionConfig::default("test".to_string());
     econfig.features = Some(features);
 
-    let ext_cx = ExtCtxt::new(sess, econfig, resolver);
+    let ext_cx = ExtCtxt::new(sess, econfig, resolver, None);
 
     let expn_id = ext_cx.resolver.expansion_for_ast_pass(
         DUMMY_SP,

src/librustc_expand/base.rs

@@ -1,4 +1,5 @@
 use crate::expand::{self, AstFragment, Invocation};
+use crate::module::DirectoryOwnership;
 
 use rustc_ast::ast::{self, Attribute, Name, NodeId, PatKind};
 use rustc_ast::mut_visit::{self, MutVisitor};
@@ -10,7 +11,7 @@ use rustc_attr::{self as attr, Deprecation, HasAttrs, Stability};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::{self, Lrc};
 use rustc_errors::{DiagnosticBuilder, DiagnosticId};
-use rustc_parse::{self, parser, DirectoryOwnership, MACRO_ARGUMENTS};
+use rustc_parse::{self, parser, MACRO_ARGUMENTS};
 use rustc_session::parse::ParseSess;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{AstPass, ExpnData, ExpnId, ExpnKind};
@@ -925,19 +926,23 @@ pub struct ExtCtxt<'a> {
     pub resolver: &'a mut dyn Resolver,
     pub current_expansion: ExpansionData,
     pub expansions: FxHashMap<Span, Vec<String>>,
+    /// Called directly after having parsed an external `mod foo;` in expansion.
+    pub(super) extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
 }
 
 impl<'a> ExtCtxt<'a> {
     pub fn new(
         parse_sess: &'a ParseSess,
         ecfg: expand::ExpansionConfig<'a>,
         resolver: &'a mut dyn Resolver,
+        extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
     ) -> ExtCtxt<'a> {
         ExtCtxt {
             parse_sess,
             ecfg,
-            root_path: PathBuf::new(),
             resolver,
+            extern_mod_loaded,
+            root_path: PathBuf::new(),
             current_expansion: ExpansionData {
                 id: ExpnId::root(),
                 depth: 0,

src/librustc_parse/config.rs → src/librustc_expand/config.rs

@@ -1,14 +1,5 @@
-//! Process the potential `cfg` attributes on a module.
-//! Also determine if the module should be included in this configuration.
-//!
-//! This module properly belongs in rustc_expand, but for now it's tied into
-//! parsing, so we leave it here to avoid complicated out-of-line dependencies.
-//!
-//! A principled solution to this wrong location would be to implement [#64197].
-//!
-//! [#64197]: https://github.com/rust-lang/rust/issues/64197
-
-use crate::{parse_in, validate_attr};
+//! Conditional compilation stripping.
+
 use rustc_ast::ast::{self, AttrItem, Attribute, MetaItem};
 use rustc_ast::attr::HasAttrs;
 use rustc_ast::mut_visit::*;
@@ -21,6 +12,7 @@ use rustc_feature::{Feature, Features, State as FeatureState};
 use rustc_feature::{
     ACCEPTED_FEATURES, ACTIVE_FEATURES, REMOVED_FEATURES, STABLE_REMOVED_FEATURES,
 };
+use rustc_parse::{parse_in, validate_attr};
 use rustc_session::parse::{feature_err, ParseSess};
 use rustc_span::edition::{Edition, ALL_EDITIONS};
 use rustc_span::symbol::{sym, Symbol};
@@ -538,12 +530,3 @@ impl<'a> MutVisitor for StripUnconfigured<'a> {
 fn is_cfg(attr: &Attribute) -> bool {
     attr.check_name(sym::cfg)
 }
-
-/// Process the potential `cfg` attributes on a module.
-/// Also determine if the module should be included in this configuration.
-pub fn process_configure_mod(sess: &ParseSess, cfg_mods: bool, attrs: &mut Vec<Attribute>) -> bool {
-    // Don't perform gated feature checking.
-    let mut strip_unconfigured = StripUnconfigured { sess, features: None };
-    strip_unconfigured.process_cfg_attrs(attrs);
-    !cfg_mods || strip_unconfigured.in_cfg(&attrs)
-}

src/librustc_expand/expand.rs

@@ -1,7 +1,9 @@
 use crate::base::*;
 use crate::config::StripUnconfigured;
+use crate::configure;
 use crate::hygiene::{ExpnData, ExpnId, ExpnKind, SyntaxContext};
 use crate::mbe::macro_rules::annotate_err_with_kind;
+use crate::module::{parse_external_mod, push_directory, Directory, DirectoryOwnership};
 use crate::placeholders::{placeholder, PlaceholderExpander};
 use crate::proc_macro::collect_derives;
 
@@ -17,10 +19,8 @@ use rustc_ast_pretty::pprust;
 use rustc_attr::{self as attr, is_builtin_attr, HasAttrs};
 use rustc_errors::{Applicability, FatalError, PResult};
 use rustc_feature::Features;
-use rustc_parse::configure;
 use rustc_parse::parser::Parser;
 use rustc_parse::validate_attr;
-use rustc_parse::DirectoryOwnership;
 use rustc_session::lint::builtin::UNUSED_DOC_COMMENTS;
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::{feature_err, ParseSess};
@@ -1427,59 +1427,83 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
                 .make_items();
         }
 
+        let mut attrs = mem::take(&mut item.attrs); // We do this to please borrowck.
+        let ident = item.ident;
+        let span = item.span;
+
         match item.kind {
             ast::ItemKind::MacCall(..) => {
+                item.attrs = attrs;
                 self.check_attributes(&item.attrs);
                 item.and_then(|item| match item.kind {
                     ItemKind::MacCall(mac) => self
-                        .collect(
-                            AstFragmentKind::Items,
-                            InvocationKind::Bang { mac, span: item.span },
-                        )
+                        .collect(AstFragmentKind::Items, InvocationKind::Bang { mac, span })
                         .make_items(),
                     _ => unreachable!(),
                 })
             }
-            ast::ItemKind::Mod(ast::Mod { inner, inline, .. })
-                if item.ident != Ident::invalid() =>
-            {
-                let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
+            ast::ItemKind::Mod(ref mut old_mod @ ast::Mod { .. }) if ident != Ident::invalid() => {
+                let sess = self.cx.parse_sess;
+                let orig_ownership = self.cx.current_expansion.directory_ownership;
                 let mut module = (*self.cx.current_expansion.module).clone();
-                module.mod_path.push(item.ident);
 
-                if inline {
-                    if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, sym::path) {
-                        self.cx.current_expansion.directory_ownership =
-                            DirectoryOwnership::Owned { relative: None };
-                        module.directory.push(&*path.as_str());
-                    } else {
-                        module.directory.push(&*item.ident.as_str());
-                    }
+                let pushed = &mut false; // Record `parse_external_mod` pushing so we can pop.
+                let dir = Directory { ownership: orig_ownership, path: module.directory };
+                let Directory { ownership, path } = if old_mod.inline {
+                    // Inline `mod foo { ... }`, but we still need to push directories.
+                    item.attrs = attrs;
+                    push_directory(ident, &item.attrs, dir)
                 } else {
-                    let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
-                    let mut path = match path {
-                        FileName::Real(path) => path,
-                        other => PathBuf::from(other.to_string()),
+                    // We have an outline `mod foo;` so we need to parse the file.
+                    let (new_mod, dir) =
+                        parse_external_mod(sess, ident, span, dir, &mut attrs, pushed);
+
+                    let krate = ast::Crate {
+                        span: new_mod.inner,
+                        module: new_mod,
+                        attrs,
+                        proc_macros: vec![],
                     };
-                    let directory_ownership = match path.file_name().unwrap().to_str() {
-                        Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
-                        Some(_) => DirectoryOwnership::Owned { relative: Some(item.ident) },
-                        None => DirectoryOwnership::UnownedViaMod,
+                    if let Some(extern_mod_loaded) = self.cx.extern_mod_loaded {
+                        extern_mod_loaded(&krate);
+                    }
+
+                    *old_mod = krate.module;
+                    item.attrs = krate.attrs;
+                    // File can have inline attributes, e.g., `#![cfg(...)]` & co. => Reconfigure.
+                    item = match self.configure(item) {
+                        Some(node) => node,
+                        None => {
+                            if *pushed {
+                                sess.included_mod_stack.borrow_mut().pop();
+                            }
+                            return Default::default();
+                        }
                     };
-                    path.pop();
-                    module.directory = path;
-                    self.cx.current_expansion.directory_ownership = directory_ownership;
-                }
+                    dir
+                };
 
+                // Set the module info before we flat map.
+                self.cx.current_expansion.directory_ownership = ownership;
+                module.directory = path;
+                module.mod_path.push(ident);
                 let orig_module =
                     mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
+
                 let result = noop_flat_map_item(item, self);
+
+                // Restore the module info.
                 self.cx.current_expansion.module = orig_module;
-                self.cx.current_expansion.directory_ownership = orig_directory_ownership;
+                self.cx.current_expansion.directory_ownership = orig_ownership;
+                if *pushed {
+                    sess.included_mod_stack.borrow_mut().pop();
+                }
                 result
             }
-
-            _ => noop_flat_map_item(item, self),
+            _ => {
+                item.attrs = attrs;
+                noop_flat_map_item(item, self)
+            }
         }
     }
 

src/librustc_expand/lib.rs

@@ -1,9 +1,11 @@
+#![feature(bool_to_option)]
 #![feature(cow_is_borrowed)]
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_span)]
+#![feature(try_blocks)]
 
 extern crate proc_macro as pm;
 
@@ -33,8 +35,10 @@ pub use mbe::macro_rules::compile_declarative_macro;
 crate use rustc_span::hygiene;
 pub mod base;
 pub mod build;
+#[macro_use]
+pub mod config;
 pub mod expand;
-pub use rustc_parse::config;
+pub mod module;
 pub mod proc_macro;
 
 crate mod mbe;