Rollup merge of #93936 - bjorn3:simplifications2, r=cjgillot

Couple of driver cleanups

* Remove the `RustcDefaultCalls` struct, which hasn't been necessary since the introduction of `rustc_interface`.
* Move the `setup_callbacks` call around for a tiny code deduplication.
* Remove the `SPAN_DEBUG` global as it isn't actually necessary.

7 files changed, 158 insertions, 199 deletions

diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index ca4e7b5142e..7eeae66d709 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -263,7 +263,7 @@ fn run_compiler(
                         describe_lints(compiler.session(), &lint_store, registered_lints);
                         return;
                     }
-                    let should_stop = RustcDefaultCalls::print_crate_info(
+                    let should_stop = print_crate_info(
                         &***compiler.codegen_backend(),
                         compiler.session(),
                         None,
@@ -292,7 +292,7 @@ fn run_compiler(
 
     interface::run_compiler(config, |compiler| {
         let sess = compiler.session();
-        let should_stop = RustcDefaultCalls::print_crate_info(
+        let should_stop = print_crate_info(
             &***compiler.codegen_backend(),
             sess,
             Some(compiler.input()),
@@ -301,13 +301,9 @@ fn run_compiler(
             compiler.temps_dir(),
         )
         .and_then(|| {
-            RustcDefaultCalls::list_metadata(
-                sess,
-                &*compiler.codegen_backend().metadata_loader(),
-                compiler.input(),
-            )
+            list_metadata(sess, &*compiler.codegen_backend().metadata_loader(), compiler.input())
         })
-        .and_then(|| RustcDefaultCalls::try_process_rlink(sess, compiler));
+        .and_then(|| try_process_rlink(sess, compiler));
 
         if should_stop == Compilation::Stop {
             return sess.compile_status();
@@ -512,10 +508,6 @@ impl Compilation {
     }
 }
 
-/// CompilerCalls instance for a regular rustc build.
-#[derive(Copy, Clone)]
-pub struct RustcDefaultCalls;
-
 fn handle_explain(registry: Registry, code: &str, output: ErrorOutputType) {
     let upper_cased_code = code.to_ascii_uppercase();
     let normalised = if upper_cased_code.starts_with('E') {
@@ -588,162 +580,157 @@ fn show_content_with_pager(content: &str) {
     }
 }
 
-impl RustcDefaultCalls {
-    pub fn try_process_rlink(sess: &Session, compiler: &interface::Compiler) -> Compilation {
-        if sess.opts.debugging_opts.link_only {
-            if let Input::File(file) = compiler.input() {
-                // FIXME: #![crate_type] and #![crate_name] support not implemented yet
-                sess.init_crate_types(collect_crate_types(sess, &[]));
-                let outputs = compiler.build_output_filenames(sess, &[]);
-                let rlink_data = fs::read(file).unwrap_or_else(|err| {
-                    sess.fatal(&format!("failed to read rlink file: {}", err));
-                });
-                let mut decoder = rustc_serialize::opaque::Decoder::new(&rlink_data, 0);
-                let codegen_results: CodegenResults =
-                    rustc_serialize::Decodable::decode(&mut decoder);
-                let result = compiler.codegen_backend().link(sess, codegen_results, &outputs);
-                abort_on_err(result, sess);
-            } else {
-                sess.fatal("rlink must be a file")
-            }
-            Compilation::Stop
+pub fn try_process_rlink(sess: &Session, compiler: &interface::Compiler) -> Compilation {
+    if sess.opts.debugging_opts.link_only {
+        if let Input::File(file) = compiler.input() {
+            // FIXME: #![crate_type] and #![crate_name] support not implemented yet
+            sess.init_crate_types(collect_crate_types(sess, &[]));
+            let outputs = compiler.build_output_filenames(sess, &[]);
+            let rlink_data = fs::read(file).unwrap_or_else(|err| {
+                sess.fatal(&format!("failed to read rlink file: {}", err));
+            });
+            let mut decoder = rustc_serialize::opaque::Decoder::new(&rlink_data, 0);
+            let codegen_results: CodegenResults = rustc_serialize::Decodable::decode(&mut decoder);
+            let result = compiler.codegen_backend().link(sess, codegen_results, &outputs);
+            abort_on_err(result, sess);
         } else {
-            Compilation::Continue
+            sess.fatal("rlink must be a file")
         }
+        Compilation::Stop
+    } else {
+        Compilation::Continue
     }
+}
 
-    pub fn list_metadata(
-        sess: &Session,
-        metadata_loader: &dyn MetadataLoader,
-        input: &Input,
-    ) -> Compilation {
-        if sess.opts.debugging_opts.ls {
-            match *input {
-                Input::File(ref ifile) => {
-                    let path = &(*ifile);
-                    let mut v = Vec::new();
-                    locator::list_file_metadata(&sess.target, path, metadata_loader, &mut v)
-                        .unwrap();
-                    println!("{}", String::from_utf8(v).unwrap());
-                }
-                Input::Str { .. } => {
-                    early_error(ErrorOutputType::default(), "cannot list metadata for stdin");
-                }
+pub fn list_metadata(
+    sess: &Session,
+    metadata_loader: &dyn MetadataLoader,
+    input: &Input,
+) -> Compilation {
+    if sess.opts.debugging_opts.ls {
+        match *input {
+            Input::File(ref ifile) => {
+                let path = &(*ifile);
+                let mut v = Vec::new();
+                locator::list_file_metadata(&sess.target, path, metadata_loader, &mut v).unwrap();
+                println!("{}", String::from_utf8(v).unwrap());
+            }
+            Input::Str { .. } => {
+                early_error(ErrorOutputType::default(), "cannot list metadata for stdin");
             }
-            return Compilation::Stop;
         }
-
-        Compilation::Continue
+        return Compilation::Stop;
     }
 
-    fn print_crate_info(
-        codegen_backend: &dyn CodegenBackend,
-        sess: &Session,
-        input: Option<&Input>,
-        odir: &Option<PathBuf>,
-        ofile: &Option<PathBuf>,
-        temps_dir: &Option<PathBuf>,
-    ) -> Compilation {
-        use rustc_session::config::PrintRequest::*;
-        // NativeStaticLibs and LinkArgs are special - printed during linking
-        // (empty iterator returns true)
-        if sess.opts.prints.iter().all(|&p| p == NativeStaticLibs || p == LinkArgs) {
-            return Compilation::Continue;
-        }
+    Compilation::Continue
+}
 
-        let attrs = match input {
-            None => None,
-            Some(input) => {
-                let result = parse_crate_attrs(sess, input);
-                match result {
-                    Ok(attrs) => Some(attrs),
-                    Err(mut parse_error) => {
-                        parse_error.emit();
-                        return Compilation::Stop;
-                    }
+fn print_crate_info(
+    codegen_backend: &dyn CodegenBackend,
+    sess: &Session,
+    input: Option<&Input>,
+    odir: &Option<PathBuf>,
+    ofile: &Option<PathBuf>,
+    temps_dir: &Option<PathBuf>,
+) -> Compilation {
+    use rustc_session::config::PrintRequest::*;
+    // NativeStaticLibs and LinkArgs are special - printed during linking
+    // (empty iterator returns true)
+    if sess.opts.prints.iter().all(|&p| p == NativeStaticLibs || p == LinkArgs) {
+        return Compilation::Continue;
+    }
+
+    let attrs = match input {
+        None => None,
+        Some(input) => {
+            let result = parse_crate_attrs(sess, input);
+            match result {
+                Ok(attrs) => Some(attrs),
+                Err(mut parse_error) => {
+                    parse_error.emit();
+                    return Compilation::Stop;
                 }
             }
-        };
-        for req in &sess.opts.prints {
-            match *req {
-                TargetList => {
-                    let mut targets =
-                        rustc_target::spec::TARGETS.iter().copied().collect::<Vec<_>>();
-                    targets.sort_unstable();
-                    println!("{}", targets.join("\n"));
-                }
-                Sysroot => println!("{}", sess.sysroot.display()),
-                TargetLibdir => println!("{}", sess.target_tlib_path.dir.display()),
-                TargetSpec => println!("{}", sess.target.to_json().pretty()),
-                FileNames | CrateName => {
-                    let input = input.unwrap_or_else(|| {
-                        early_error(ErrorOutputType::default(), "no input file provided")
-                    });
-                    let attrs = attrs.as_ref().unwrap();
-                    let t_outputs = rustc_interface::util::build_output_filenames(
-                        input, odir, ofile, temps_dir, attrs, sess,
-                    );
-                    let id = rustc_session::output::find_crate_name(sess, attrs, input);
-                    if *req == PrintRequest::CrateName {
-                        println!("{}", id);
-                        continue;
-                    }
-                    let crate_types = collect_crate_types(sess, attrs);
-                    for &style in &crate_types {
-                        let fname =
-                            rustc_session::output::filename_for_input(sess, style, &id, &t_outputs);
-                        println!("{}", fname.file_name().unwrap().to_string_lossy());
-                    }
+        }
+    };
+    for req in &sess.opts.prints {
+        match *req {
+            TargetList => {
+                let mut targets = rustc_target::spec::TARGETS.iter().copied().collect::<Vec<_>>();
+                targets.sort_unstable();
+                println!("{}", targets.join("\n"));
+            }
+            Sysroot => println!("{}", sess.sysroot.display()),
+            TargetLibdir => println!("{}", sess.target_tlib_path.dir.display()),
+            TargetSpec => println!("{}", sess.target.to_json().pretty()),
+            FileNames | CrateName => {
+                let input = input.unwrap_or_else(|| {
+                    early_error(ErrorOutputType::default(), "no input file provided")
+                });
+                let attrs = attrs.as_ref().unwrap();
+                let t_outputs = rustc_interface::util::build_output_filenames(
+                    input, odir, ofile, temps_dir, attrs, sess,
+                );
+                let id = rustc_session::output::find_crate_name(sess, attrs, input);
+                if *req == PrintRequest::CrateName {
+                    println!("{}", id);
+                    continue;
                 }
-                Cfg => {
-                    let mut cfgs = sess
-                        .parse_sess
-                        .config
-                        .iter()
-                        .filter_map(|&(name, value)| {
-                            // Note that crt-static is a specially recognized cfg
-                            // directive that's printed out here as part of
-                            // rust-lang/rust#37406, but in general the
-                            // `target_feature` cfg is gated under
-                            // rust-lang/rust#29717. For now this is just
-                            // specifically allowing the crt-static cfg and that's
-                            // it, this is intended to get into Cargo and then go
-                            // through to build scripts.
-                            if (name != sym::target_feature || value != Some(sym::crt_dash_static))
-                                && !sess.is_nightly_build()
-                                && find_gated_cfg(|cfg_sym| cfg_sym == name).is_some()
-                            {
-                                return None;
-                            }
-
-                            if let Some(value) = value {
-                                Some(format!("{}=\"{}\"", name, value))
-                            } else {
-                                Some(name.to_string())
-                            }
-                        })
-                        .collect::<Vec<String>>();
-
-                    cfgs.sort();
-                    for cfg in cfgs {
-                        println!("{}", cfg);
-                    }
+                let crate_types = collect_crate_types(sess, attrs);
+                for &style in &crate_types {
+                    let fname =
+                        rustc_session::output::filename_for_input(sess, style, &id, &t_outputs);
+                    println!("{}", fname.file_name().unwrap().to_string_lossy());
                 }
-                RelocationModels
-                | CodeModels
-                | TlsModels
-                | TargetCPUs
-                | StackProtectorStrategies
-                | TargetFeatures => {
-                    codegen_backend.print(*req, sess);
+            }
+            Cfg => {
+                let mut cfgs = sess
+                    .parse_sess
+                    .config
+                    .iter()
+                    .filter_map(|&(name, value)| {
+                        // Note that crt-static is a specially recognized cfg
+                        // directive that's printed out here as part of
+                        // rust-lang/rust#37406, but in general the
+                        // `target_feature` cfg is gated under
+                        // rust-lang/rust#29717. For now this is just
+                        // specifically allowing the crt-static cfg and that's
+                        // it, this is intended to get into Cargo and then go
+                        // through to build scripts.
+                        if (name != sym::target_feature || value != Some(sym::crt_dash_static))
+                            && !sess.is_nightly_build()
+                            && find_gated_cfg(|cfg_sym| cfg_sym == name).is_some()
+                        {
+                            return None;
+                        }
+
+                        if let Some(value) = value {
+                            Some(format!("{}=\"{}\"", name, value))
+                        } else {
+                            Some(name.to_string())
+                        }
+                    })
+                    .collect::<Vec<String>>();
+
+                cfgs.sort();
+                for cfg in cfgs {
+                    println!("{}", cfg);
                 }
-                // Any output here interferes with Cargo's parsing of other printed output
-                NativeStaticLibs => {}
-                LinkArgs => {}
             }
+            RelocationModels
+            | CodeModels
+            | TlsModels
+            | TargetCPUs
+            | StackProtectorStrategies
+            | TargetFeatures => {
+                codegen_backend.print(*req, sess);
+            }
+            // Any output here interferes with Cargo's parsing of other printed output
+            NativeStaticLibs => {}
+            LinkArgs => {}
         }
-        Compilation::Stop
     }
+    Compilation::Stop
 }
 
 /// Prints version information
diff --git a/compiler/rustc_interface/src/callbacks.rs b/compiler/rustc_interface/src/callbacks.rs
index 3c7908fae79..a18e2d1d638 100644
--- a/compiler/rustc_interface/src/callbacks.rs
+++ b/compiler/rustc_interface/src/callbacks.rs
@@ -4,7 +4,7 @@
 //! `rustc_data_structures::AtomicRef` type, which allows us to setup a global
 //! static which can then be set in this file at program startup.
 //!
-//! See `SPAN_DEBUG` for an example of how to set things up.
+//! See `SPAN_TRACK` for an example of how to set things up.
 //!
 //! The functions in this file should fall back to the default set in their
 //! origin crate when the `TyCtxt` is not present in TLS.
@@ -13,18 +13,6 @@ use rustc_errors::{Diagnostic, TRACK_DIAGNOSTICS};
 use rustc_middle::ty::tls;
 use std::fmt;
 
-/// This is a callback from `rustc_ast` as it cannot access the implicit state
-/// in `rustc_middle` otherwise.
-fn span_debug(span: rustc_span::Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    tls::with_opt(|tcx| {
-        if let Some(tcx) = tcx {
-            rustc_span::debug_with_source_map(span, f, tcx.sess.source_map())
-        } else {
-            rustc_span::default_span_debug(span, f)
-        }
-    })
-}
-
 fn track_span_parent(def_id: rustc_span::def_id::LocalDefId) {
     tls::with_opt(|tcx| {
         if let Some(tcx) = tcx {
@@ -65,7 +53,6 @@ fn def_id_debug(def_id: rustc_hir::def_id::DefId, f: &mut fmt::Formatter<'_>) ->
 /// Sets up the callbacks in prior crates which we want to refer to the
 /// TyCtxt in.
 pub fn setup_callbacks() {
-    rustc_span::SPAN_DEBUG.swap(&(span_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
     rustc_span::SPAN_TRACK.swap(&(track_span_parent as fn(_)));
     rustc_hir::def_id::DEF_ID_DEBUG.swap(&(def_id_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
     TRACK_DIAGNOSTICS.swap(&(track_diagnostic as fn(&_)));
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 237aef1cf23..8bd24487b78 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -186,6 +186,8 @@ pub struct Config {
 }
 
 pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R) -> R {
+    crate::callbacks::setup_callbacks();
+
     let registry = &config.registry;
     let (mut sess, codegen_backend) = util::create_session(
         config.opts,
@@ -238,7 +240,7 @@ pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R
 pub fn run_compiler<R: Send>(mut config: Config, f: impl FnOnce(&Compiler) -> R + Send) -> R {
     tracing::trace!("run_compiler");
     let stderr = config.stderr.take();
-    util::setup_callbacks_and_run_in_thread_pool_with_globals(
+    util::run_in_thread_pool_with_globals(
         config.opts.edition,
         config.opts.debugging_opts.threads,
         &stderr,
diff --git a/compiler/rustc_interface/src/lib.rs b/compiler/rustc_interface/src/lib.rs
index eebeabbd452..dcad3036cc2 100644
--- a/compiler/rustc_interface/src/lib.rs
+++ b/compiler/rustc_interface/src/lib.rs
@@ -15,6 +15,7 @@ mod proc_macro_decls;
 mod queries;
 pub mod util;
 
+pub use callbacks::setup_callbacks;
 pub use interface::{run_compiler, Config};
 pub use passes::{DEFAULT_EXTERN_QUERY_PROVIDERS, DEFAULT_QUERY_PROVIDERS};
 pub use queries::Queries;
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index f74cadfebac..d206f2644e0 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -128,7 +128,7 @@ fn scoped_thread<F: FnOnce() -> R + Send, R: Send>(cfg: thread::Builder, f: F) -
 }
 
 #[cfg(not(parallel_compiler))]
-pub fn setup_callbacks_and_run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
+pub fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
     edition: Edition,
     _threads: usize,
     stderr: &Option<Arc<Mutex<Vec<u8>>>>,
@@ -140,8 +140,6 @@ pub fn setup_callbacks_and_run_in_thread_pool_with_globals<F: FnOnce() -> R + Se
         cfg = cfg.stack_size(size);
     }
 
-    crate::callbacks::setup_callbacks();
-
     let main_handler = move || {
         rustc_span::create_session_globals_then(edition, || {
             io::set_output_capture(stderr.clone());
@@ -176,14 +174,12 @@ unsafe fn handle_deadlock() {
 }
 
 #[cfg(parallel_compiler)]
-pub fn setup_callbacks_and_run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
+pub fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
     edition: Edition,
     threads: usize,
     stderr: &Option<Arc<Mutex<Vec<u8>>>>,
     f: F,
 ) -> R {
-    crate::callbacks::setup_callbacks();
-
     let mut config = rayon::ThreadPoolBuilder::new()
         .thread_name(|_| "rustc".to_string())
         .acquire_thread_handler(jobserver::acquire_thread)
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 823a927fd8c..3ce9f852c3d 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -1013,37 +1013,25 @@ pub fn with_source_map<T, F: FnOnce() -> T>(source_map: Lrc<SourceMap>, f: F) ->
     f()
 }
 
-pub fn debug_with_source_map(
-    span: Span,
-    f: &mut fmt::Formatter<'_>,
-    source_map: &SourceMap,
-) -> fmt::Result {
-    write!(f, "{} ({:?})", source_map.span_to_diagnostic_string(span), span.ctxt())
-}
-
-pub fn default_span_debug(span: Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    with_session_globals(|session_globals| {
-        if let Some(source_map) = &*session_globals.source_map.borrow() {
-            debug_with_source_map(span, f, source_map)
-        } else {
-            f.debug_struct("Span")
-                .field("lo", &span.lo())
-                .field("hi", &span.hi())
-                .field("ctxt", &span.ctxt())
-                .finish()
-        }
-    })
-}
-
 impl fmt::Debug for Span {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (*SPAN_DEBUG)(*self, f)
+        with_session_globals(|session_globals| {
+            if let Some(source_map) = &*session_globals.source_map.borrow() {
+                write!(f, "{} ({:?})", source_map.span_to_diagnostic_string(*self), self.ctxt())
+            } else {
+                f.debug_struct("Span")
+                    .field("lo", &self.lo())
+                    .field("hi", &self.hi())
+                    .field("ctxt", &self.ctxt())
+                    .finish()
+            }
+        })
     }
 }
 
 impl fmt::Debug for SpanData {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (*SPAN_DEBUG)(Span::new(self.lo, self.hi, self.ctxt, self.parent), f)
+        fmt::Debug::fmt(&Span::new(self.lo, self.hi, self.ctxt, self.parent), f)
     }
 }
 
@@ -2003,8 +1991,6 @@ pub struct FileLines {
     pub lines: Vec<LineInfo>,
 }
 
-pub static SPAN_DEBUG: AtomicRef<fn(Span, &mut fmt::Formatter<'_>) -> fmt::Result> =
-    AtomicRef::new(&(default_span_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
 pub static SPAN_TRACK: AtomicRef<fn(LocalDefId)> = AtomicRef::new(&((|_| {}) as fn(_)));
 
 // _____________________________________________________________________________
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 68028604fa4..c3205165040 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -688,7 +688,7 @@ fn main_args(at_args: &[String]) -> MainResult {
         Ok(opts) => opts,
         Err(code) => return if code == 0 { Ok(()) } else { Err(ErrorReported) },
     };
-    rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals(
+    rustc_interface::util::run_in_thread_pool_with_globals(
         options.edition,
         1, // this runs single-threaded, even in a parallel compiler
         &None,