message: add './miri many-seeds', and respect MIRIFLAGS in './miri run'
diff: @@ -20,6 +20,7 @@ to the final `cargo test` invocation.
  ./miri run <flags>:
  Build miri, set up a sysroot and then run the driver with the given <flags>.
  +(Also respects MIRIFLAGS environment variable.)
  The commands above also exist in a "-debug" variant (e.g. "./miri run-debug
  <flags>") which uses debug builds instead of release builds, for faster build
  @@ -31,6 +32,11 @@ Format all sources and tests. <flags> are passed to `rustfmt`.
  ./miri clippy <flags>:
  Format all sources and tests. <flags> are passed to `cargo clippy`.
  +./miri many-seeds <command>:
  +Runs <command> over and over again with different seeds for Miri. The MIRIFLAGS
  +variable is set to its original value appended with ` -Zmiri-seed=$SEED` for
  +many different seeds.
  +
  ENVIRONMENT VARIABLES
  MIRI_SYSROOT:
  @@ -41,6 +47,20 @@ Pass extra flags to all cargo invocations.
  EOF
  )
  +# Determine command.
  +COMMAND="$1"
  +[ $# -gt 0 ] && shift
  +
  +## Handle some commands early, since they should *not* alter the environment.
  +case "$COMMAND" in
  +many-seeds)
  + for SEED in $({ echo obase=16; seq 0 255; } | bc); do
  + MIRIFLAGS="$MIRIFLAGS -Zmiri-seed=$SEED" $@ || { echo "Failing seed: $SEED"; break; }
  + done
  + exit 0
  + ;;
  +esac
  +
  ## Preparation
  # macOS does not have a useful readlink/realpath so we have to use Python instead...
  MIRIDIR=$(dirname "$(python3 -c 'import os, sys; print(os.path.realpath(sys.argv[1]))' "$0")")
  @@ -99,10 +119,6 @@ find_sysroot() {
  ## Main
  -# Determine command.
  -COMMAND="$1"
  -[ $# -gt 0 ] && shift
  -
  # Determine flags passed to all cargo invocations.
  # This is a bit more annoying that one would hope due to
  # <https://github.com/rust-lang/cargo/issues/6992>.
  @@ -166,7 +182,7 @@ run|run-debug)
  $CARGO build $CARGO_BUILD_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml
  find_sysroot
  # Then run the actual command.
  - exec $CARGO run $CARGO_BUILD_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml -- --sysroot "$MIRI_SYSROOT" "$@"
  + exec $CARGO run $CARGO_BUILD_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml -- --sysroot "$MIRI_SYSROOT" $MIRIFLAGS "$@"
  ;;
  fmt)
  find "$MIRIDIR" -not \( -name target -prune \) -name '*.rs' \
  