[green] Isolate and bind the host mpy-cross compiler

Signed-off-by: Viwat Vchirawongkwin <viwat.v@chula.ac.th>

Author: yyods

firmware/scripts/build.sh

@@ -238,8 +238,17 @@ unset \
   MAKEFLAGS \
   MFLAGS \
   GNUMAKEFLAGS \
-  MAKEOVERRIDES
-make -C "$UPSTREAM_DIR/mpy-cross" || { echo "build.sh: mpy-cross build failed" >&2; exit 1; }
+  MAKEOVERRIDES \
+  BUILD \
+  MICROPY_MPYCROSS
+make -C "$UPSTREAM_DIR/mpy-cross" BUILD=build ||
+  { echo "build.sh: mpy-cross build failed" >&2; exit 1; }
+MICROPY_MPYCROSS="$UPSTREAM_DIR/mpy-cross/build/mpy-cross"
+if [ ! -x "$MICROPY_MPYCROSS" ]; then
+  echo "build.sh: rebuilt mpy-cross is missing or not executable" >&2
+  exit 1
+fi
+export MICROPY_MPYCROSS
 
 # ESP-IDF maps its project, build, component, and toolchain paths when
 # CONFIG_APP_REPRODUCIBLE_BUILD=y, but MicroPython sources above ports/esp32

tests/firmware_tests/host/test_release_hardening.py

@@ -761,12 +761,26 @@ def __init__(self):
             printf '%s\n' "${MICROPY_MPYCROSS-}" \
               >> "$PYBLE_MPY_CROSS_ENV_LOG"
             output=""
+            command_directory=""
+            previous=""
             for argument in "$@"; do
+              if [ "$previous" = "-C" ]; then
+                command_directory="$argument"
+              fi
               case "$argument" in
                 BUILD=*) output="${argument#BUILD=}" ;;
               esac
+              previous="$argument"
             done
-            if [ -n "$output" ]; then
+            if [ "$(basename "$command_directory")" = "mpy-cross" ]; then
+              case "$output" in
+                /*) compiler="$output/mpy-cross" ;;
+                *) compiler="$command_directory/$output/mpy-cross" ;;
+              esac
+              mkdir -p "$(dirname "$compiler")"
+              printf '#!/bin/sh\nexit 0\n' > "$compiler"
+              chmod 755 "$compiler"
+            elif [ -n "$output" ]; then
               mkdir -p "$output"
               cp -R "$PYBLE_FAKE_ARTIFACTS"/. "$output"/
             fi
@@ -842,6 +856,7 @@ def build(self) -> subprocess.CompletedProcess[str]:
                 "PYBLE_MPY_CROSS_ENV_LOG": str(self.mpy_cross_environment_log),
                 "PYBLE_ESPTOOL_LOG": str(self.esptool_log),
                 "BUILD": str(self.root / "hostile-mpy-cross-build"),
+                "MICROPY_MPYCROSS": str(self.root / "hostile-mpy-cross"),
                 "CFLAGS_EXTRA": (
                     "-ffile-prefix-map=/ambient/source=/HOSTILE "
                     "-DHOSTILE_BUILD_FLAG=1"