Remove CARGO_TARGET_CACHE_NAME, use BUILDKITE_LABEL

.buildkite/hooks/post-command

@@ -3,15 +3,14 @@
 #
 # Save target/ for the next CI build on this machine
 #
-if [[ -n $CARGO_TARGET_CACHE_NAME ]]; then
-  (
-    d=$HOME/cargo-target-cache/"$CARGO_TARGET_CACHE_NAME"
-    mkdir -p "$d"
-    set -x
-    rsync -a --delete --link-dest="$PWD" target "$d"
-    du -hs "$d"
-  )
-fi
+(
+  set -x
+  d=$HOME/cargo-target-cache/"$BUILDKITE_LABEL"
+  mkdir -p "$d"
+  set -x
+  rsync -a --delete --link-dest="$PWD" target "$d"
+  du -hs "$d"
+)
 
 #
 # Add job_stats data point

.buildkite/hooks/pre-command

@@ -11,8 +11,9 @@ export PS4="++"
 #
 # Restore target/ from the previous CI build on this machine
 #
-[[ -n "$CARGO_TARGET_CACHE_NAME" ]] || (
-  d=$HOME/cargo-target-cache/"$CARGO_TARGET_CACHE_NAME"
+(
+  set -x
+  d=$HOME/cargo-target-cache/"$BUILDKITE_LABEL"
 
   if [[ -d $d ]]; then
     du -hs "$d"
@@ -24,6 +25,5 @@ export PS4="++"
   fi
 
   mkdir -p "$d"/target
-  set -x
   rsync -a --delete --link-dest="$d" "$d"/target .
 )

ci/buildkite.yml

@@ -4,37 +4,25 @@ steps:
     timeout_in_minutes: 20
   - command: "ci/docker-run.sh solanalabs/rust:1.31.0 ci/test-checks.sh"
     name: "checks"
-    env:
-      CARGO_TARGET_CACHE_NAME: "checks"
     timeout_in_minutes: 30
   - wait
   - command: "ci/test-stable-perf.sh"
     name: "stable-perf"
-    env:
-      CARGO_TARGET_CACHE_NAME: "stable-perf"
     timeout_in_minutes: 20
     agents:
       - "queue=cuda"
   - command: "ci/test-bench.sh"
     name: "bench"
-    env:
-      CARGO_TARGET_CACHE_NAME: "nightly"
     timeout_in_minutes: 30
   - command: "ci/docker-run.sh solanalabs/rust:1.31.0 ci/test-stable.sh"
     name: "stable"
-    env:
-      CARGO_TARGET_CACHE_NAME: "stable"
     timeout_in_minutes: 30
   - command: "ci/docker-run.sh solanalabs/rust-nightly:2018-12-05 ci/test-nightly.sh"
     name: "nightly"
-    env:
-      CARGO_TARGET_CACHE_NAME: "nightly"
     timeout_in_minutes: 30
   # TODO: Fix and re-enable test-large-network.sh
   # - command: "ci/test-large-network.sh || true"
   #   name: "large-network [ignored]"
-  #   env:
-  #     CARGO_TARGET_CACHE_NAME: "stable"
   #   timeout_in_minutes: 20
   #   agents:
   #     - "queue=large"