Install and prepare Miri in the primary container

The other tools exist in all channels and Miri is the odd one out, so
we make it look a bit more odd.

compiler/base/Dockerfile

@@ -46,7 +46,9 @@ RUN curl https://sh.rustup.rs -sSf | sh -s -- \
     --default-toolchain "${channel}" \
     --target wasm32-unknown-unknown \
     --component rustfmt \
-    --component clippy
+    --component clippy \
+    --component rust-src
+RUN if [ "${channel}" = 'nightly' ]; then rustup component add miri; fi
 
 COPY --chown=playground entrypoint.sh /playground/tools/
 
@@ -111,11 +113,13 @@ ARG channel
 RUN cargo build
 RUN cargo build --release
 RUN cargo clippy
+RUN if [ "${channel}" = 'nightly' ]; then cargo miri setup; cargo miri run; fi
 RUN rm src/*.rs
 
 COPY --from=modify-cargo-toml /playground/modify-cargo-toml/target/release/modify-cargo-toml /playground/.cargo/bin
 COPY --from=build-orchestrator /playground/.cargo/bin/worker /playground/.cargo/bin/worker
 COPY --from=wasm-tools /playground/.cargo/bin/wasm-tools /playground/.cargo/bin
-COPY --chown=playground cargo-wasm /playground/.cargo/bin/
+COPY --chown=playground cargo-wasm /playground/.cargo/bin
+COPY --chown=playground cargo-miri-playground /playground/.cargo/bin
 
 ENTRYPOINT ["/playground/tools/entrypoint.sh"]

compiler/base/cargo-miri-playground

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+set -eu
+
+export MIRI_SYSROOT=~/.cache/miri
+export MIRIFLAGS="-Zmiri-disable-isolation"
+exec cargo miri run

compiler/miri/Dockerfile

@@ -1,13 +1,6 @@
 ARG base_image=shepmaster/rust-nightly
 FROM ${base_image}
 
-RUN rustup component add rust-src miri
-
-RUN echo 'fn main() {}' > src/main.rs
-RUN cargo miri setup
-RUN cargo miri run
-RUN rm src/*.rs
-
-ADD --chown=playground cargo-miri-playground /playground/.cargo/bin
+# The base image takes care of all this for now
 
 ENTRYPOINT ["/playground/tools/entrypoint.sh"]