Rollup merge of rust-lang#70344 - Centril:hir-pretty, r=eddyb

Decouple `rustc_hir::print` into `rustc_hir_pretty`

High level summary:
- The HIR pretty printer, `rustc_hir::print` is moved into a new crate `rustc_hir_pretty`.
- `rustc_ast_pretty` and `rustc_errors` are dropped as `rustc_hir` dependencies.
- The dependence on HIR pretty is generally reduced, leaving `rustc_save_analysis`, `rustdoc`, `rustc_metadata`, and `rustc_driver` as the remaining clients.

The main goal here is to reduce `rustc_hir`'s dependencies and its size such that it can start and finish earlier, thereby working towards rust-lang#65031.

r? @Zoxc

Cargo.lock

@@ -3668,6 +3668,7 @@ dependencies = [
  "rustc_errors",
  "rustc_feature",
  "rustc_hir",
+ "rustc_hir_pretty",
  "rustc_interface",
  "rustc_lint",
  "rustc_metadata",
@@ -3742,9 +3743,7 @@ dependencies = [
  "lazy_static 1.4.0",
  "log",
  "rustc_ast",
- "rustc_ast_pretty",
  "rustc_data_structures",
- "rustc_errors",
  "rustc_index",
  "rustc_macros",
  "rustc_span",
@@ -3753,6 +3752,18 @@ dependencies = [
  "smallvec 1.0.0",
 ]
 
+[[package]]
+name = "rustc_hir_pretty"
+version = "0.0.0"
+dependencies = [
+ "rustc_ast",
+ "rustc_ast_pretty",
+ "rustc_data_structures",
+ "rustc_hir",
+ "rustc_span",
+ "rustc_target",
+]
+
 [[package]]
 name = "rustc_incremental"
 version = "0.0.0"
@@ -3903,6 +3914,7 @@ dependencies = [
  "rustc_errors",
  "rustc_expand",
  "rustc_hir",
+ "rustc_hir_pretty",
  "rustc_index",
  "rustc_session",
  "rustc_span",
@@ -4087,6 +4099,7 @@ dependencies = [
  "rustc_ast_pretty",
  "rustc_data_structures",
  "rustc_hir",
+ "rustc_hir_pretty",
  "rustc_parse",
  "rustc_session",
  "rustc_span",

src/librustc/hir/map/mod.rs

@@ -10,7 +10,6 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, Definitions};
 use rustc_hir::intravisit;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
-use rustc_hir::print::Nested;
 use rustc_hir::*;
 use rustc_index::vec::IndexVec;
 use rustc_span::hygiene::MacroKind;
@@ -890,20 +889,18 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    /// Get a representation of this `id` for debugging purposes.
+    /// NOTE: Do NOT use this in diagnostics!
     pub fn node_to_string(&self, id: HirId) -> String {
-        hir_id_to_string(self, id, true)
-    }
-
-    pub fn hir_to_user_string(&self, id: HirId) -> String {
-        hir_id_to_string(self, id, false)
-    }
-
-    pub fn hir_to_pretty_string(&self, id: HirId) -> String {
-        print::to_string(self, |s| s.print_node(self.get(id)))
+        hir_id_to_string(self, id)
     }
 }
 
 impl<'hir> intravisit::Map<'hir> for Map<'hir> {
+    fn find(&self, hir_id: HirId) -> Option<Node<'hir>> {
+        self.find(hir_id)
+    }
+
     fn body(&self, id: BodyId) -> &'hir Body<'hir> {
         self.body(id)
     }
@@ -982,23 +979,8 @@ pub(super) fn index_hir<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> &'tcx Indexe
     tcx.arena.alloc(IndexedHir { crate_hash, map })
 }
 
-/// Identical to the `PpAnn` implementation for `hir::Crate`,
-/// except it avoids creating a dependency on the whole crate.
-impl<'hir> print::PpAnn for Map<'hir> {
-    fn nested(&self, state: &mut print::State<'_>, nested: print::Nested) {
-        match nested {
-            Nested::Item(id) => state.print_item(self.expect_item(id.id)),
-            Nested::TraitItem(id) => state.print_trait_item(self.trait_item(id)),
-            Nested::ImplItem(id) => state.print_impl_item(self.impl_item(id)),
-            Nested::Body(id) => state.print_expr(&self.body(id).value),
-            Nested::BodyParamPat(id, i) => state.print_pat(&self.body(id).params[i].pat),
-        }
-    }
-}
-
-fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
+fn hir_id_to_string(map: &Map<'_>, id: HirId) -> String {
     let id_str = format!(" (hir_id={})", id);
-    let id_str = if include_id { &id_str[..] } else { "" };
 
     let path_str = || {
         // This functionality is used for debugging, try to use `TyCtxt` to get
@@ -1019,6 +1001,9 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
         })
     };
 
+    let span_str = || map.tcx.sess.source_map().span_to_snippet(map.span(id)).unwrap_or_default();
+    let node_str = |prefix| format!("{} {}{}", prefix, span_str(), id_str);
+
     match map.find(id) {
         Some(Node::Item(item)) => {
             let item_str = match item.kind {
@@ -1069,22 +1054,20 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
         Some(Node::Field(ref field)) => {
             format!("field {} in {}{}", field.ident, path_str(), id_str)
         }
-        Some(Node::AnonConst(_)) => format!("const {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Expr(_)) => format!("expr {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Stmt(_)) => format!("stmt {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::PathSegment(_)) => {
-            format!("path segment {}{}", map.hir_to_pretty_string(id), id_str)
-        }
-        Some(Node::Ty(_)) => format!("type {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::TraitRef(_)) => format!("trait_ref {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Binding(_)) => format!("local {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Pat(_)) => format!("pat {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Param(_)) => format!("param {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Arm(_)) => format!("arm {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Block(_)) => format!("block {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Local(_)) => format!("local {}{}", map.hir_to_pretty_string(id), id_str),
+        Some(Node::AnonConst(_)) => node_str("const"),
+        Some(Node::Expr(_)) => node_str("expr"),
+        Some(Node::Stmt(_)) => node_str("stmt"),
+        Some(Node::PathSegment(_)) => node_str("path segment"),
+        Some(Node::Ty(_)) => node_str("type"),
+        Some(Node::TraitRef(_)) => node_str("trait ref"),
+        Some(Node::Binding(_)) => node_str("local"),
+        Some(Node::Pat(_)) => node_str("pat"),
+        Some(Node::Param(_)) => node_str("param"),
+        Some(Node::Arm(_)) => node_str("arm"),
+        Some(Node::Block(_)) => node_str("block"),
+        Some(Node::Local(_)) => node_str("local"),
         Some(Node::Ctor(..)) => format!("ctor {}{}", path_str(), id_str),
-        Some(Node::Lifetime(_)) => format!("lifetime {}{}", map.hir_to_pretty_string(id), id_str),
+        Some(Node::Lifetime(_)) => node_str("lifetime"),
         Some(Node::GenericParam(ref param)) => format!("generic_param {:?}{}", param, id_str),
         Some(Node::Visibility(ref vis)) => format!("visibility {:?}{}", vis, id_str),
         Some(Node::MacroDef(_)) => format!("macro {}{}", path_str(), id_str),

src/librustc_driver/Cargo.toml

@@ -21,6 +21,7 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_hir = { path = "../librustc_hir" }
+rustc_hir_pretty = { path = "../librustc_hir_pretty" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_mir = { path = "../librustc_mir" }
 rustc_parse = { path = "../librustc_parse" }

src/librustc_driver/pretty.rs

@@ -7,7 +7,7 @@ use rustc_ast::ast;
 use rustc_ast_pretty::pprust;
 use rustc_hir as hir;
 use rustc_hir::def_id::LOCAL_CRATE;
-use rustc_hir::print as pprust_hir;
+use rustc_hir_pretty as pprust_hir;
 use rustc_mir::util::{write_mir_graphviz, write_mir_pretty};
 use rustc_session::config::{Input, PpMode, PpSourceMode};
 use rustc_session::Session;
@@ -155,7 +155,7 @@ impl<'hir> pprust::PpAnn for NoAnn<'hir> {}
 impl<'hir> pprust_hir::PpAnn for NoAnn<'hir> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
         if let Some(tcx) = self.tcx {
-            pprust_hir::PpAnn::nested(&tcx.hir(), state, nested)
+            pprust_hir::PpAnn::nested(&(&tcx.hir() as &dyn hir::intravisit::Map<'_>), state, nested)
         }
     }
 }
@@ -228,7 +228,7 @@ impl<'hir> HirPrinterSupport<'hir> for IdentifiedAnnotation<'hir> {
 impl<'hir> pprust_hir::PpAnn for IdentifiedAnnotation<'hir> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
         if let Some(ref tcx) = self.tcx {
-            pprust_hir::PpAnn::nested(&tcx.hir(), state, nested)
+            pprust_hir::PpAnn::nested(&(&tcx.hir() as &dyn hir::intravisit::Map<'_>), state, nested)
         }
     }
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
@@ -334,7 +334,8 @@ impl<'a, 'tcx> pprust_hir::PpAnn for TypedAnnotation<'a, 'tcx> {
         if let pprust_hir::Nested::Body(id) = nested {
             self.tables.set(self.tcx.body_tables(id));
         }
-        pprust_hir::PpAnn::nested(&self.tcx.hir(), state, nested);
+        let pp_ann = &(&self.tcx.hir() as &dyn hir::intravisit::Map<'_>);
+        pprust_hir::PpAnn::nested(pp_ann, state, nested);
         self.tables.set(old_tables);
     }
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {

src/librustc_hir/Cargo.toml

@@ -10,13 +10,11 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-rustc_ast_pretty = { path = "../librustc_ast_pretty" }
 rustc_target = { path = "../librustc_target" }
 rustc_macros = { path = "../librustc_macros" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_index = { path = "../librustc_index" }
 rustc_span = { path = "../librustc_span" }
-rustc_errors = { path = "../librustc_errors" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 rustc_ast = { path = "../librustc_ast" }
 lazy_static = "1"