Auto merge of #117301 - saethlin:finish-rmeta-encoding, r=WaffleLapkin

Call FileEncoder::finish in rmeta encoding

Fixes https://github.com/rust-lang/rust/issues/117254

The bug here was that rmeta encoding never called FileEncoder::finish. Now it does. Most of the changes here are needed to support that, since rmeta encoding wants to finish _then_ access the File in the encoder, so finish can't move out.

I tried adding a `cfg(debug_assertions)` exploding Drop impl to FileEncoder that checked for finish being called before dropping, but fatal errors cause unwinding so this isn't really possible. If we encounter a fatal error with a dirty FileEncoder, the Drop impl ICEs even though the implementation is correct. If we try to paper over that by wrapping FileEncoder in ManuallyDrop then that just erases the fact that Drop automatically checks that we call finish on all paths.

I also changed the name of DepGraph::encode to DepGraph::finish_encoding, because that's what it does and it makes the fact that it is the path to FileEncoder::finish less confusing.

r? `@WaffleLapkin`

1 files changed, 9 insertions, 1 deletions

diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 1c65cf19cde..bee27dc2d69 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -1,6 +1,6 @@
 use crate::errors::{FailedWritingFile, RustcErrorFatal, RustcErrorUnexpectedAnnotation};
 use crate::interface::{Compiler, Result};
-use crate::{passes, util};
+use crate::{errors, passes, util};
 
 use rustc_ast as ast;
 use rustc_codegen_ssa::traits::CodegenBackend;
@@ -15,6 +15,7 @@ use rustc_metadata::creader::CStore;
 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, CrateType, OutputFilenames, OutputType};
 use rustc_session::cstore::Untracked;
 use rustc_session::output::find_crate_name;
@@ -102,6 +103,10 @@ 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).map_err(|mut parse_error| parse_error.emit())
@@ -317,6 +322,9 @@ 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.emit_err(errors::FailedWritingFile { path: &path, error });
+        }
 
         ret
     }