Move dep_graph.finish_encoding() into save_dep_graph

Author: bjorn3

compiler/rustc_incremental/messages.ftl

@@ -46,6 +46,9 @@ incremental_delete_partial = failed to delete partly initialized session dir `{$
 
 incremental_delete_workproduct = file-system error deleting outdated file `{$path}`: {$err}
 
+incremental_failed_writing_file =
+    failed to write file {$path}: {$error}"
+
 incremental_finalize = error finalizing incremental compilation session directory `{$path}`: {$err}
 
 incremental_finalized_gc_failed =

compiler/rustc_incremental/src/errors.rs

@@ -1,7 +1,15 @@
 use rustc_macros::Diagnostic;
 use rustc_span::{symbol::Ident, Span, Symbol};
+use std::io;
 use std::path::{Path, PathBuf};
 
+#[derive(Diagnostic)]
+#[diag(incremental_failed_writing_file)]
+pub struct FailedWritingFile<'a> {
+    pub path: &'a Path,
+    pub error: io::Error,
+}
+
 #[derive(Diagnostic)]
 #[diag(incremental_unrecognized_depnode)]
 pub struct UnrecognizedDepNode {

compiler/rustc_incremental/src/persist/save.rs

@@ -35,6 +35,11 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
         }
         // This is going to be deleted in finalize_session_directory, so let's not create it.
         if sess.dcx().has_errors_or_delayed_bugs().is_some() {
+            // Dropping the DepGraph without calling finish_encoding ICEs even when the incr comp
+            // session has already been invalidated due to an error.
+            if let Err((path, error)) = tcx.dep_graph.finish_encoding() {
+                tcx.sess.dcx().emit_fatal(errors::FailedWritingFile { path: &path, error });
+            }
             return;
         }
 
@@ -76,6 +81,11 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
                 });
             },
         );
+
+        // FIXME finalize dep graph before renaming?
+        if let Err((path, error)) = tcx.dep_graph.finish_encoding() {
+            tcx.sess.dcx().emit_fatal(errors::FailedWritingFile { path: &path, error });
+        }
     })
 }
 

compiler/rustc_interface/src/queries.rs

@@ -1,6 +1,6 @@
 use crate::errors::FailedWritingFile;
 use crate::interface::{Compiler, Result};
-use crate::{errors, passes};
+use crate::passes;
 
 use rustc_ast as ast;
 use rustc_codegen_ssa::traits::CodegenBackend;
@@ -12,7 +12,6 @@ use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepGraph;
 use rustc_middle::ty::{GlobalCtxt, TyCtxt};
-use rustc_serialize::opaque::FileEncodeResult;
 use rustc_session::config::{self, OutputFilenames, OutputType};
 use rustc_session::Session;
 use std::any::Any;
@@ -95,10 +94,6 @@ impl<'tcx> Queries<'tcx> {
         }
     }
 
-    pub fn finish(&self) -> FileEncodeResult {
-        if let Some(gcx) = self.gcx_cell.get() { gcx.finish() } else { Ok(0) }
-    }
-
     pub fn parse(&self) -> Result<QueryResult<'_, ast::Crate>> {
         self.parse.compute(|| passes::parse(&self.compiler.sess))
     }
@@ -228,9 +223,6 @@ impl Compiler {
         // The timer's lifetime spans the dropping of `queries`, which contains
         // the global context.
         _timer = Some(self.sess.timer("free_global_ctxt"));
-        if let Err((path, error)) = queries.finish() {
-            self.sess.dcx().emit_fatal(errors::FailedWritingFile { path: &path, error });
-        }
 
         ret
     }

compiler/rustc_middle/src/ty/context.rs

@@ -1291,10 +1291,6 @@ impl<'tcx> GlobalCtxt<'tcx> {
 
         tls::enter_context(&icx, || f(icx.tcx))
     }
-
-    pub fn finish(&self) -> FileEncodeResult {
-        self.dep_graph.finish_encoding()
-    }
 }
 
 /// This is used to get a reference to a `GlobalCtxt` if one is available.