From ca72f9ed7065a601bd2b1ec80889ec7bad177598 Mon Sep 17 00:00:00 2001
From: Joshua Nelson <jyn514@gmail.com>
Date: Fri, 22 Jan 2021 13:46:52 -0500
Subject: [PATCH] Calculate self-profile strings in `Compiler::enter` instead
 in codegen

This avoids each tool having to separately find and call
`self_profile_alloc_strings`.

- Don't compute the global context if it hasn't yet been computed

  This avoids giving extraneous errors about unresolved names if an error
  occurs during parsing.
---
 compiler/rustc_interface/src/passes.rs  |  7 -------
 compiler/rustc_interface/src/queries.rs | 16 +++++++++++++---
 src/librustdoc/lib.rs                   |  9 +++------
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index ead2512d3b2..7031234e108 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -1017,13 +1017,6 @@ pub fn start_codegen<'tcx>(
     tcx.sess.time("assert_dep_graph", || rustc_incremental::assert_dep_graph(tcx));
     tcx.sess.time("serialize_dep_graph", || rustc_incremental::save_dep_graph(tcx));
 
-    // We assume that no queries are run past here. If there are new queries
-    // after this point, they'll show up as "<unknown>" in self-profiling data.
-    {
-        let _prof_timer = tcx.prof.generic_activity("self_profile_alloc_query_strings");
-        tcx.alloc_self_profile_query_strings();
-    }
-
     info!("Post-codegen\n{:?}", tcx.debug_stats());
 
     if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 9c49f926d41..ac6b6d03115 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -417,9 +417,19 @@ impl Compiler {
         let queries = Queries::new(&self);
         let ret = f(&queries);
 
-        if self.session().opts.debugging_opts.query_stats {
-            if let Ok(gcx) = queries.global_ctxt() {
-                gcx.peek_mut().print_stats();
+        // NOTE: intentionally does not compute the global context if it hasn't been built yet,
+        // since that likely means there was a parse error.
+        if let Some(Ok(gcx)) = &mut *queries.global_ctxt.result.borrow_mut() {
+            // We assume that no queries are run past here. If there are new queries
+            // after this point, they'll show up as "<unknown>" in self-profiling data.
+            {
+                let _prof_timer =
+                    queries.session().prof.generic_activity("self_profile_alloc_query_strings");
+                gcx.enter(|tcx| tcx.alloc_self_profile_query_strings());
+            }
+
+            if self.session().opts.debugging_opts.query_stats {
+                gcx.print_stats();
             }
         }
 
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 19d2de58ffb..780a3b509c7 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -539,7 +539,7 @@ fn main_options(options: config::Options) -> MainResult {
                 sess.fatal("Compilation failed, aborting rustdoc");
             }
 
-            let mut global_ctxt = abort_on_err(queries.global_ctxt(), sess).take();
+            let mut global_ctxt = abort_on_err(queries.global_ctxt(), sess).peek_mut();
 
             global_ctxt.enter(|tcx| {
                 let (mut krate, render_info, render_opts) = sess.time("run_global_ctxt", || {
@@ -568,7 +568,7 @@ fn main_options(options: config::Options) -> MainResult {
                 info!("going to format");
                 let (error_format, edition, debugging_options) = diag_opts;
                 let diag = core::new_handler(error_format, None, &debugging_options);
-                let main_result = match output_format {
+                match output_format {
                     None | Some(config::OutputFormat::Html) => sess.time("render_html", || {
                         run_renderer::<html::render::Context<'_>>(
                             krate,
@@ -589,10 +589,7 @@ fn main_options(options: config::Options) -> MainResult {
                             tcx,
                         )
                     }),
-                };
-                // NOTE: this is normally called in codegen, but rustdoc never goes to codegen.
-                tcx.alloc_self_profile_query_strings();
-                main_result
+                }
             })
         })
     })