From 794bf8a850b3e83705845de398b51547d5366bb1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Rakic?= <remy.rakic+github@gmail.com>
Date: Sat, 28 Oct 2023 19:00:49 +0000
Subject: [PATCH 1/3] pass `CODEGEN_BACKENDS` to docker

---
 src/ci/docker/run.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/ci/docker/run.sh b/src/ci/docker/run.sh
index 99e3ce199f451..0b535532f695b 100755
--- a/src/ci/docker/run.sh
+++ b/src/ci/docker/run.sh
@@ -288,6 +288,7 @@ docker \
   --env DIST_TRY_BUILD \
   --env PR_CI_JOB \
   --env OBJDIR_ON_HOST="$objdir" \
+  --env CODEGEN_BACKENDS \
   --init \
   --rm \
   rust-ci \

From aefd7ace91b58eb8cf00817de24a42ae2b3956d3 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Sat, 28 Oct 2023 19:11:51 +0000
Subject: [PATCH 2/3] Ensure the rustc-codegen-cranelift-preview component is
 never empty

Either generate it with the actual codegen backend dylib or omit it
entirely when the cranelift backend is disabled for this build.
---
 src/bootstrap/src/core/build_steps/dist.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
index b578c5ec29500..197ce78d8859c 100644
--- a/src/bootstrap/src/core/build_steps/dist.rs
+++ b/src/bootstrap/src/core/build_steps/dist.rs
@@ -1305,6 +1305,10 @@ impl Step for CodegenBackend {
             return None;
         }
 
+        if !builder.config.rust_codegen_backends.contains(&self.backend) {
+            return None;
+        }
+
         if self.backend == "cranelift" {
             if !target_supports_cranelift_backend(self.compiler.host) {
                 builder.info("target not supported by rustc_codegen_cranelift. skipping");
@@ -1343,12 +1347,15 @@ impl Step for CodegenBackend {
         let backends_dst = PathBuf::from("lib").join(&backends_rel);
 
         let backend_name = format!("rustc_codegen_{}", backend);
+        let mut found_backend = false;
         for backend in fs::read_dir(&backends_src).unwrap() {
             let file_name = backend.unwrap().file_name();
             if file_name.to_str().unwrap().contains(&backend_name) {
                 tarball.add_file(backends_src.join(file_name), &backends_dst, 0o644);
+                found_backend = true;
             }
         }
+        assert!(found_backend);
 
         Some(tarball.generate())
     }

From f656accdf534bc58a021e2d7f04bf5900e2ba8ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Rakic?= <remy.rakic+github@gmail.com>
Date: Sun, 29 Oct 2023 13:12:02 +0000
Subject: [PATCH 3/3] handle dry runs in `dist::CodegenBackend`

self.number_of_times_dry_runs_have_caused_issues += 1;
---
 src/bootstrap/src/core/build_steps/dist.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
index 197ce78d8859c..6e80c55c8ce3c 100644
--- a/src/bootstrap/src/core/build_steps/dist.rs
+++ b/src/bootstrap/src/core/build_steps/dist.rs
@@ -1298,6 +1298,10 @@ impl Step for CodegenBackend {
     }
 
     fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
+        if builder.config.dry_run() {
+            return None;
+        }
+
         // This prevents rustc_codegen_cranelift from being built for "dist"
         // or "install" on the stable/beta channels. It is not yet stable and
         // should not be included.