Auto merge of #68133 - Centril:slimmer-syntax, r=petrochenkov

Slimmer syntax

High-level summary of changes:

- The `syntax::node_count` pass is moved into `rustc_ast_passes`. This works towards improving #65031 by making compiling `syntax` go faster.

- The `syntax::{GLOBALS, with_globals, ..}` business is consolidated into `syntax::attr` for cleaner code and future possible improvements.

- The pretty printer loses its dependency on `ParseSess`, opting to use `SourceMap` & friends directly instead.

- Some drive by cleanup of `syntax::attr::HasAttr` happens.

- Builtin attribute logic (`syntax::attr::builtin`) + `syntax::attr::allow_internal_unstable` is moved into a new `rustc_attr` crate. More logic from `syntax::attr` should be moved into that crate over time. This also means that `syntax` loses all mentions of `ParseSess`, which enables the next point.

- The pretty printer `syntax::print` is moved into a new crate `rustc_ast_pretty`.

- `rustc_session::node_id` is moved back as `syntax::node_id`. As a result, `syntax` gets to drop dependencies on `rustc_session` (and implicitly `rustc_target`), `rustc_error_codes`, and `rustc_errors`. Moreover `rustc_hir` gets to drop its dependency on `rustc_session` as well. At this point, these crates are mostly "pure data crates", which is approaching a desirable end state.

  - We should consider renaming `syntax` to `rustc_ast` now.

Author: bors

Diff for: Cargo.lock

@@ -3093,6 +3093,7 @@ dependencies = [
  "rustc-rayon",
  "rustc-rayon-core",
  "rustc_apfloat",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3358,6 +3359,7 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_ast_pretty",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -3374,6 +3376,8 @@ name = "rustc_ast_passes"
 version = "0.0.0"
 dependencies = [
  "log",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3383,12 +3387,40 @@ dependencies = [
  "syntax",
 ]
 
+[[package]]
+name = "rustc_ast_pretty"
+version = "0.0.0"
+dependencies = [
+ "log",
+ "rustc_data_structures",
+ "rustc_span",
+ "syntax",
+]
+
+[[package]]
+name = "rustc_attr"
+version = "0.0.0"
+dependencies = [
+ "rustc_ast_pretty",
+ "rustc_data_structures",
+ "rustc_errors",
+ "rustc_feature",
+ "rustc_macros",
+ "rustc_session",
+ "rustc_span",
+ "serialize",
+ "smallvec 1.0.0",
+ "syntax",
+]
+
 [[package]]
 name = "rustc_builtin_macros"
 version = "0.0.0"
 dependencies = [
  "fmt_macros",
  "log",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_expand",
@@ -3411,6 +3443,7 @@ dependencies = [
  "log",
  "rustc",
  "rustc-demangle",
+ "rustc_attr",
  "rustc_codegen_ssa",
  "rustc_codegen_utils",
  "rustc_data_structures",
@@ -3442,6 +3475,7 @@ dependencies = [
  "num_cpus",
  "rustc",
  "rustc_apfloat",
+ "rustc_attr",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_errors",
@@ -3506,6 +3540,7 @@ dependencies = [
  "lazy_static 1.4.0",
  "log",
  "rustc",
+ "rustc_ast_pretty",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_error_codes",
@@ -3552,6 +3587,8 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc_ast_passes",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3581,11 +3618,11 @@ version = "0.0.0"
 name = "rustc_hir"
 version = "0.0.0"
 dependencies = [
+ "rustc_ast_pretty",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_index",
  "rustc_macros",
- "rustc_session",
  "rustc_span",
  "rustc_target",
  "serialize",
@@ -3628,6 +3665,7 @@ dependencies = [
  "rustc-rayon",
  "rustc_ast_lowering",
  "rustc_ast_passes",
+ "rustc_attr",
  "rustc_builtin_macros",
  "rustc_codegen_llvm",
  "rustc_codegen_ssa",
@@ -3672,6 +3710,8 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3712,6 +3752,8 @@ dependencies = [
  "log",
  "memmap",
  "rustc",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_expand",
@@ -3739,6 +3781,8 @@ dependencies = [
  "polonius-engine",
  "rustc",
  "rustc_apfloat",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -3761,6 +3805,7 @@ dependencies = [
  "log",
  "rustc",
  "rustc_apfloat",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -3780,6 +3825,8 @@ version = "0.0.0"
 dependencies = [
  "bitflags",
  "log",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3797,6 +3844,7 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3827,6 +3875,7 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -3844,6 +3893,8 @@ dependencies = [
  "log",
  "rustc",
  "rustc_ast_lowering",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_expand",
@@ -3864,6 +3915,7 @@ dependencies = [
  "rls-data",
  "rls-span",
  "rustc",
+ "rustc_ast_pretty",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_hir",
@@ -3887,6 +3939,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "serialize",
+ "syntax",
 ]
 
 [[package]]
@@ -3961,6 +4014,7 @@ dependencies = [
  "arena",
  "log",
  "rustc",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -4481,12 +4535,9 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc_data_structures",
- "rustc_errors",
- "rustc_feature",
  "rustc_index",
  "rustc_lexer",
  "rustc_macros",
- "rustc_session",
  "rustc_span",
  "scoped-tls",
  "serialize",

Diff for: src/librustc/Cargo.toml

@@ -21,6 +21,7 @@ rustc-rayon = "0.3.0"
 rustc-rayon-core = "0.3.0"
 polonius-engine = "0.11.0"
 rustc_apfloat = { path = "../librustc_apfloat" }
+rustc_attr = { path = "../librustc_attr" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_target = { path = "../librustc_target" }

Diff for: src/librustc/hir/map/definitions.rs

@@ -10,12 +10,12 @@ use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_index::vec::IndexVec;
-use rustc_session::node_id::NodeMap;
 use rustc_session::CrateDisambiguator;
 use rustc_span::hygiene::ExpnId;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use syntax::ast;
+use syntax::node_id::NodeMap;
 
 use std::borrow::Borrow;
 use std::fmt::Write;

Diff for: src/librustc/ich/impls_hir.rs

@@ -3,12 +3,12 @@
 
 use crate::hir::map::DefPathHash;
 use crate::ich::{Fingerprint, NodeIdHashingMode, StableHashingContext};
+use rustc_attr as attr;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX};
 use smallvec::SmallVec;
 use std::mem;
-use syntax::attr;
 
 impl<'ctx> rustc_hir::HashStableContext for StableHashingContext<'ctx> {
     #[inline]

Diff for: src/librustc/middle/codegen_fn_attrs.rs

@@ -1,6 +1,6 @@
 use crate::mir::mono::Linkage;
+use rustc_attr::{InlineAttr, OptimizeAttr};
 use rustc_span::symbol::Symbol;
-use syntax::attr::{InlineAttr, OptimizeAttr};
 
 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 pub struct CodegenFnAttrs {

Diff for: src/librustc/middle/stability.rs

@@ -5,19 +5,20 @@ pub use self::StabilityLevel::*;
 
 use crate::session::{DiagnosticMessageId, Session};
 use crate::ty::{self, TyCtxt};
+use rustc_attr::{self as attr, ConstStability, Deprecation, RustcDeprecation, Stability};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{Applicability, DiagnosticBuilder};
 use rustc_feature::GateIssue;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
 use rustc_hir::{self, HirId};
-use rustc_session::lint::{self, BuiltinLintDiagnostics, Lint, LintBuffer};
+use rustc_session::lint::builtin::{DEPRECATED, DEPRECATED_IN_FUTURE, SOFT_UNSTABLE};
+use rustc_session::lint::{BuiltinLintDiagnostics, Lint, LintBuffer};
+use rustc_session::parse::feature_err_issue;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{MultiSpan, Span};
 use syntax::ast::CRATE_NODE_ID;
-use syntax::attr::{self, ConstStability, Deprecation, RustcDeprecation, Stability};
-use syntax::sess::feature_err_issue;
 
 use std::num::NonZeroU32;
 
@@ -97,7 +98,7 @@ pub fn report_unstable(
     issue: Option<NonZeroU32>,
     is_soft: bool,
     span: Span,
-    soft_handler: impl FnOnce(&'static lint::Lint, Span, &str),
+    soft_handler: impl FnOnce(&'static Lint, Span, &str),
 ) {
     let msg = match reason {
         Some(r) => format!("use of unstable library feature '{}': {}", feature, r),
@@ -119,7 +120,7 @@ pub fn report_unstable(
     let fresh = sess.one_time_diagnostics.borrow_mut().insert(error_id);
     if fresh {
         if is_soft {
-            soft_handler(lint::builtin::SOFT_UNSTABLE, span, &msg)
+            soft_handler(SOFT_UNSTABLE, span, &msg)
         } else {
             feature_err_issue(&sess.parse_sess, feature, span, GateIssue::Library(issue), &msg)
                 .emit();
@@ -175,19 +176,19 @@ fn deprecation_message_common(message: String, reason: Option<Symbol>) -> String
 
 pub fn deprecation_message(depr: &Deprecation, path: &str) -> (String, &'static Lint) {
     let message = format!("use of deprecated item '{}'", path);
-    (deprecation_message_common(message, depr.note), lint::builtin::DEPRECATED)
+    (deprecation_message_common(message, depr.note), DEPRECATED)
 }
 
 pub fn rustc_deprecation_message(depr: &RustcDeprecation, path: &str) -> (String, &'static Lint) {
     let (message, lint) = if deprecation_in_effect(&depr.since.as_str()) {
-        (format!("use of deprecated item '{}'", path), lint::builtin::DEPRECATED)
+        (format!("use of deprecated item '{}'", path), DEPRECATED)
     } else {
         (
             format!(
                 "use of item '{}' that will be deprecated in future version {}",
                 path, depr.since
             ),
-            lint::builtin::DEPRECATED_IN_FUTURE,
+            DEPRECATED_IN_FUTURE,
         )
     };
     (deprecation_message_common(message, Some(depr.reason)), lint)

Diff for: src/librustc/mir/mono.rs

@@ -3,6 +3,7 @@ use crate::ich::{Fingerprint, NodeIdHashingMode, StableHashingContext};
 use crate::session::config::OptLevel;
 use crate::ty::print::obsolete::DefPathBasedNames;
 use crate::ty::{subst::InternalSubsts, Instance, InstanceDef, SymbolName, TyCtxt};
+use rustc_attr::InlineAttr;
 use rustc_data_structures::base_n;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -12,7 +13,6 @@ use rustc_span::source_map::Span;
 use rustc_span::symbol::Symbol;
 use std::fmt;
 use std::hash::Hash;
-use syntax::attr::InlineAttr;
 
 /// Describes how a monomorphization will be instantiated in object files.
 #[derive(PartialEq)]

Diff for: src/librustc/traits/on_unimplemented.rs

@@ -3,13 +3,13 @@ use fmt_macros::{Parser, Piece, Position};
 use crate::ty::{self, GenericParamDefKind, TyCtxt};
 use crate::util::common::ErrorReported;
 
+use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::struct_span_err;
 use rustc_hir::def_id::DefId;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
 use syntax::ast::{MetaItem, NestedMetaItem};
-use syntax::attr;
 
 #[derive(Clone, Debug)]
 pub struct OnUnimplementedFormatString(Symbol);