Auto merge of #2681 - RalfJung:seed, r=oli-obk

make miri-seed a regular integer, and also set layout-seed in many-seeds

This makes the seed format consistent between `-Zlayout-seed` and `-Zmiri-seed`.

src/tools/miri/README.md

@@ -195,7 +195,7 @@ randomness that is used to determine allocation base addresses. The following
 snippet calls Miri in a loop with different values for the seed:
 
 ```
-for SEED in $({ echo obase=16; seq 0 255; } | bc); do
+for SEED in $(seq 0 255); do
   echo "Trying seed: $SEED"
   MIRIFLAGS=-Zmiri-seed=$SEED cargo miri test || { echo "Failing seed: $SEED"; break; };
 done
@@ -303,7 +303,7 @@ environment variable. We first document the most relevant and most commonly used
   tell what it is doing when a program just keeps running. You can customize how frequently the
   report is printed via `-Zmiri-report-progress=<blocks>`, which prints the report every N basic
   blocks.
-* `-Zmiri-seed=<hex>` configures the seed of the RNG that Miri uses to resolve non-determinism. This
+* `-Zmiri-seed=<num>` configures the seed of the RNG that Miri uses to resolve non-determinism. This
   RNG is used to pick base addresses for allocations, to determine preemption and failure of
   `compare_exchange_weak`, and to control store buffering for weak memory emulation. When isolation
   is enabled (the default), this is also used to emulate system entropy. The default seed is 0. You

src/tools/miri/miri

@@ -174,9 +174,9 @@ rustc-push)
     fi
     ;;
 many-seeds)
-    for SEED in $({ echo obase=16; seq 0 255; } | bc); do
+    for SEED in $(seq 0 255); do
         echo "Trying seed: $SEED"
-        MIRIFLAGS="$MIRIFLAGS -Zmiri-seed=$SEED" $@ || { echo "Failing seed: $SEED"; break; }
+        MIRIFLAGS="$MIRIFLAGS -Zlayout-seed=$SEED -Zmiri-seed=$SEED" $@ || { echo "Failing seed: $SEED"; break; }
     done
     exit 0
     ;;

src/tools/miri/src/bin/miri.rs

@@ -394,10 +394,9 @@ fn main() {
             if miri_config.seed.is_some() {
                 show_error!("Cannot specify -Zmiri-seed multiple times!");
             }
-            let seed = u64::from_str_radix(param, 16)
-                        .unwrap_or_else(|_| show_error!(
-                            "-Zmiri-seed should only contain valid hex digits [0-9a-fA-F] and must fit into a u64 (max 16 characters)"
-                        ));
+            let seed = param.parse::<u64>().unwrap_or_else(|_| {
+                show_error!("-Zmiri-seed must be an integer that fits into u64")
+            });
             miri_config.seed = Some(seed);
         } else if let Some(_param) = arg.strip_prefix("-Zmiri-env-exclude=") {
             show_error!(

src/tools/miri/test-cargo-miri/run-test.py

@@ -133,7 +133,7 @@ def test_cargo_miri_test():
     test("`cargo miri test`",
         cargo_miri("test"),
         default_ref, "test.stderr-empty.ref",
-        env={'MIRIFLAGS': "-Zmiri-permissive-provenance -Zmiri-seed=feed"},
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance -Zmiri-seed=4242"},
     )
     test("`cargo miri test` (no isolation, no doctests)",
         cargo_miri("test") + ["--bins", "--tests"], # no `--lib`, we disabled that in `Cargo.toml`