Auto merge of #64272 - Mark-Simulacrum:parallel-handler, r=estebank

Refactor librustc_errors::Handler API

This should be reviewed by-commit.

The last commit moves all fields into an inner struct behind a single lock; this is done to prevent possible deadlocks in a multi-threaded compiler, as well as inconsistent state observation.

12 files changed, 31 insertions, 28 deletions

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 384c0555c85..a6be5b10178 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -1048,9 +1048,6 @@ impl<'a> ExtCtxt<'a> {
     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
         self.parse_sess.span_diagnostic.span_warn(sp, msg);
     }
-    pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
-        self.parse_sess.span_diagnostic.span_unimpl(sp, msg);
-    }
     pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
         self.parse_sess.span_diagnostic.span_bug(sp, msg);
     }
diff --git a/src/libsyntax/ext/proc_macro_server.rs b/src/libsyntax/ext/proc_macro_server.rs
index 544ec789d80..dfec9ee2880 100644
--- a/src/libsyntax/ext/proc_macro_server.rs
+++ b/src/libsyntax/ext/proc_macro_server.rs
@@ -4,7 +4,7 @@ use crate::parse::{self, token, ParseSess};
 use crate::parse::lexer::comments;
 use crate::tokenstream::{self, DelimSpan, IsJoint::*, TokenStream, TreeAndJoint};
 
-use errors::{Diagnostic, DiagnosticBuilder};
+use errors::Diagnostic;
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::{BytePos, FileName, MultiSpan, Pos, SourceFile, Span};
 use syntax_pos::symbol::{kw, sym, Symbol};
@@ -650,7 +650,7 @@ impl server::Diagnostic for Rustc<'_> {
         diag.sub(level.to_internal(), msg, MultiSpan::from_spans(spans), None);
     }
     fn emit(&mut self, diag: Self::Diagnostic) {
-        DiagnosticBuilder::new_diagnostic(&self.sess.span_diagnostic, diag).emit()
+        self.sess.span_diagnostic.emit_diagnostic(&diag);
     }
 }
 
diff --git a/src/libsyntax/json.rs b/src/libsyntax/json.rs
index ada46f7bc5a..5cdea3aabbe 100644
--- a/src/libsyntax/json.rs
+++ b/src/libsyntax/json.rs
@@ -12,7 +12,7 @@
 use crate::source_map::{SourceMap, FilePathMapping};
 
 use errors::registry::Registry;
-use errors::{DiagnosticBuilder, SubDiagnostic, CodeSuggestion, SourceMapper};
+use errors::{SubDiagnostic, CodeSuggestion, SourceMapper};
 use errors::{DiagnosticId, Applicability};
 use errors::emitter::{Emitter, HumanReadableErrorType};
 
@@ -32,6 +32,7 @@ pub struct JsonEmitter {
     pretty: bool,
     ui_testing: bool,
     json_rendered: HumanReadableErrorType,
+    external_macro_backtrace: bool,
 }
 
 impl JsonEmitter {
@@ -40,6 +41,7 @@ impl JsonEmitter {
         source_map: Lrc<SourceMap>,
         pretty: bool,
         json_rendered: HumanReadableErrorType,
+        external_macro_backtrace: bool,
     ) -> JsonEmitter {
         JsonEmitter {
             dst: Box::new(io::stderr()),
@@ -48,13 +50,18 @@ impl JsonEmitter {
             pretty,
             ui_testing: false,
             json_rendered,
+            external_macro_backtrace,
         }
     }
 
-    pub fn basic(pretty: bool, json_rendered: HumanReadableErrorType) -> JsonEmitter {
+    pub fn basic(
+        pretty: bool,
+        json_rendered: HumanReadableErrorType,
+        external_macro_backtrace: bool,
+    ) -> JsonEmitter {
         let file_path_mapping = FilePathMapping::empty();
         JsonEmitter::stderr(None, Lrc::new(SourceMap::new(file_path_mapping)),
-                            pretty, json_rendered)
+                            pretty, json_rendered, external_macro_backtrace)
     }
 
     pub fn new(
@@ -63,6 +70,7 @@ impl JsonEmitter {
         source_map: Lrc<SourceMap>,
         pretty: bool,
         json_rendered: HumanReadableErrorType,
+        external_macro_backtrace: bool,
     ) -> JsonEmitter {
         JsonEmitter {
             dst,
@@ -71,6 +79,7 @@ impl JsonEmitter {
             pretty,
             ui_testing: false,
             json_rendered,
+            external_macro_backtrace,
         }
     }
 
@@ -80,8 +89,8 @@ impl JsonEmitter {
 }
 
 impl Emitter for JsonEmitter {
-    fn emit_diagnostic(&mut self, db: &DiagnosticBuilder<'_>) {
-        let data = Diagnostic::from_diagnostic_builder(db, self);
+    fn emit_diagnostic(&mut self, db: &errors::Diagnostic) {
+        let data = Diagnostic::from_errors_diagnostic(db, self);
         let result = if self.pretty {
             writeln!(&mut self.dst, "{}", as_pretty_json(&data))
         } else {
@@ -189,7 +198,7 @@ struct ArtifactNotification<'a> {
 }
 
 impl Diagnostic {
-    fn from_diagnostic_builder(db: &DiagnosticBuilder<'_>,
+    fn from_errors_diagnostic(db: &errors::Diagnostic,
                                je: &JsonEmitter)
                                -> Diagnostic {
         let sugg = db.suggestions.iter().map(|sugg| {
@@ -219,8 +228,9 @@ impl Diagnostic {
         }
         let buf = BufWriter::default();
         let output = buf.clone();
-        je.json_rendered.new_emitter(Box::new(buf), Some(je.sm.clone()), false, None)
-            .ui_testing(je.ui_testing).emit_diagnostic(db);
+        je.json_rendered.new_emitter(
+            Box::new(buf), Some(je.sm.clone()), false, None, je.external_macro_backtrace
+        ).ui_testing(je.ui_testing).emit_diagnostic(db);
         let output = Arc::try_unwrap(output.0).unwrap().into_inner().unwrap();
         let output = String::from_utf8(output).unwrap();
 
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index aaf6f3e537e..b4ae1e87bca 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -60,12 +60,12 @@ macro_rules! panictry {
 macro_rules! panictry_buffer {
     ($handler:expr, $e:expr) => ({
         use std::result::Result::{Ok, Err};
-        use errors::{FatalError, DiagnosticBuilder};
+        use errors::FatalError;
         match $e {
             Ok(e) => e,
             Err(errs) => {
                 for e in errs {
-                    DiagnosticBuilder::new_diagnostic($handler, e).emit();
+                    $handler.emit_diagnostic(&e);
                 }
                 FatalError.raise()
             }
diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index bba70973631..cf6151d17b1 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -302,14 +302,14 @@ impl<'a> Parser<'a> {
             Ok(lit) => {
                 return Ok(ast::NestedMetaItem::Literal(lit))
             }
-            Err(ref mut err) => self.diagnostic().cancel(err)
+            Err(ref mut err) => err.cancel(),
         }
 
         match self.parse_meta_item() {
             Ok(mi) => {
                 return Ok(ast::NestedMetaItem::MetaItem(mi))
             }
-            Err(ref mut err) => self.diagnostic().cancel(err)
+            Err(ref mut err) => err.cancel(),
         }
 
         let found = self.this_token_to_string();
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs
index 2d7f4f71ca4..59de5f14123 100644
--- a/src/libsyntax/parse/diagnostics.rs
+++ b/src/libsyntax/parse/diagnostics.rs
@@ -197,10 +197,6 @@ impl<'a> Parser<'a> {
         self.sess.span_diagnostic.span_bug(sp, m)
     }
 
-    crate fn cancel(&self, err: &mut DiagnosticBuilder<'_>) {
-        self.sess.span_diagnostic.cancel(err)
-    }
-
     crate fn diagnostic(&self) -> &'a errors::Handler {
         &self.sess.span_diagnostic
     }
@@ -426,15 +422,13 @@ impl<'a> Parser<'a> {
     /// Eats and discards tokens until one of `kets` is encountered. Respects token trees,
     /// passes through any errors encountered. Used for error recovery.
     crate fn eat_to_tokens(&mut self, kets: &[&TokenKind]) {
-        let handler = self.diagnostic();
-
         if let Err(ref mut err) = self.parse_seq_to_before_tokens(
             kets,
             SeqSep::none(),
             TokenExpectType::Expect,
             |p| Ok(p.parse_token_tree()),
         ) {
-            handler.cancel(err);
+            err.cancel();
         }
     }
 
diff --git a/src/libsyntax/parse/lexer/tests.rs b/src/libsyntax/parse/lexer/tests.rs
index c1ec41902e2..de301b1fc49 100644
--- a/src/libsyntax/parse/lexer/tests.rs
+++ b/src/libsyntax/parse/lexer/tests.rs
@@ -18,6 +18,7 @@ fn mk_sess(sm: Lrc<SourceMap>) -> ParseSess {
         false,
         false,
         None,
+        false,
     );
     ParseSess::with_span_handler(Handler::with_emitter(true, None, Box::new(emitter)), sm)
 }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index f7b87d154fe..fa4c1043122 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -304,7 +304,7 @@ fn file_to_source_file(sess: &ParseSess, path: &Path, spanopt: Option<Span>)
     match try_file_to_source_file(sess, path, spanopt) {
         Ok(source_file) => source_file,
         Err(d) => {
-            DiagnosticBuilder::new_diagnostic(&sess.span_diagnostic, d).emit();
+            sess.span_diagnostic.emit_diagnostic(&d);
             FatalError.raise();
         }
     }
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 41c3747b950..d0c865a7b8e 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -777,7 +777,7 @@ impl<'a> Parser<'a> {
                         ex = ExprKind::Lit(literal);
                     }
                     Err(mut err) => {
-                        self.cancel(&mut err);
+                        err.cancel();
                         return Err(self.expected_expression_found());
                     }
                 }
diff --git a/src/libsyntax/parse/parser/pat.rs b/src/libsyntax/parse/parser/pat.rs
index 08ee3a6bd86..3c624959ead 100644
--- a/src/libsyntax/parse/parser/pat.rs
+++ b/src/libsyntax/parse/parser/pat.rs
@@ -537,7 +537,7 @@ impl<'a> Parser<'a> {
         mut err: DiagnosticBuilder<'a>,
         expected: Expected,
     ) -> PResult<'a, P<Pat>> {
-        self.cancel(&mut err);
+        err.cancel();
 
         let expected = expected.unwrap_or("pattern");
         let msg = format!("expected {}, found {}", expected, self.this_token_descr());
diff --git a/src/libsyntax/parse/parser/stmt.rs b/src/libsyntax/parse/parser/stmt.rs
index 04bd61a4cfb..02da56f6e35 100644
--- a/src/libsyntax/parse/parser/stmt.rs
+++ b/src/libsyntax/parse/parser/stmt.rs
@@ -361,7 +361,7 @@ impl<'a> Parser<'a> {
                 }
                 Err(mut e) => {
                     self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
-                    self.cancel(&mut e);
+                    e.cancel();
                 }
                 _ => ()
             }
diff --git a/src/libsyntax/tests.rs b/src/libsyntax/tests.rs
index 540881b0a54..f510ac9273d 100644
--- a/src/libsyntax/tests.rs
+++ b/src/libsyntax/tests.rs
@@ -147,6 +147,7 @@ fn test_harness(file_text: &str, span_labels: Vec<SpanLabel>, expected_output: &
             false,
             false,
             None,
+            false,
         );
         let handler = Handler::with_emitter(true, None, Box::new(emitter));
         handler.span_err(msp, "foo");