Toolchain: Trust cache blindly

This is necessary because cache reusability will be determined by Github Actions.

Note that we only cache if explicitly asked to do so,
which only happens on Github Actions.

Toolchain/BuildIt.sh

@@ -19,11 +19,6 @@ MAKE="make"
 MD5SUM="md5sum"
 NPROC="nproc"
 
-# Each cache entry is 70 MB. 5 entries are 350 MiB.
-# It seems that Travis starts having trouble around a total
-# cache size of 9 GiB, so I think this is a good amount.
-KEEP_CACHE_COUNT=5
-
 if command -v ginstall &>/dev/null; then
  INSTALL=ginstall
 else
@@ -77,60 +72,41 @@ GCC_BASE_URL="http:https://ftp.gnu.org/gnu/gcc"
 
 pushd "$DIR"
  if [ "${TRY_USE_LOCAL_TOOLCHAIN}" = "y" ] ; then
- echo "Checking cached toolchain:"
- # TODO: This is still overly pessimistic.
- DEPS_CONFIG="\
- uname=$(uname),TARGET=${TARGET},
- BuildItHash=$($MD5SUM "$(basename "$0")"),
- MAKE=${MAKE},MD5SUM=${MD5SUM},NPROC=${NPROC},
- CC=${CC},CXX=${CXX},with_gmp=${with_gmp},LDFLAGS=${LDFLAGS},
- BINUTILS_VERSION=${BINUTILS_VERSION},BINUTILS_MD5SUM=${BINUTILS_MD5SUM},
- GCC_VERSION=${GCC_VERSION},GCC_MD5SUM=${GCC_MD5SUM}"
- DEPS_HASH=$("$DIR/ComputeDependenciesHash.sh" "$MD5SUM" <<<"${DEPS_CONFIG}")
- DEPS_HASH_EXIT_CODE="$?"
- CACHED_TOOLCHAIN_ARCHIVE="Cache/ToolchainLocal_${DEPS_HASH}.tar.gz"
- if [ "$DEPS_HASH_EXIT_CODE" -ne 0 ] ; then
- # Make it stand out more
- echo
- echo
- echo
- echo
- echo "Dependency hashing failed"
- echo "Will rebuild toolchain from scratch, and NOT SAVE THE RESULT."
- echo "Someone should look into this, but for now it'll work, albeit inefficient."
- echo
- echo
- echo
- echo
- # Should be empty anyway, but just to make sure:
- DEPS_HASH=""
- elif [ -r "${CACHED_TOOLCHAIN_ARCHIVE}" ] ; then
+ # The actual logic had to be moved to .github/workflows/cmake.yml.
+ # Github Actions guarantees that Toolchain/Cache/ is empty on a cache
+ # miss, and non-empty on a cache hit.
+ # The following logic is correct *only* because of that.
+
+ mkdir -p Cache
+ echo "Cache (before):"
+ ls -l Cache
+ CACHED_TOOLCHAIN_ARCHIVE="Cache/ToolchainBinariesGithubActions.tar.gz"
+ if [ -r "${CACHED_TOOLCHAIN_ARCHIVE}" ] ; then
  echo "Cache at ${CACHED_TOOLCHAIN_ARCHIVE} exists!"
  echo "Extracting toolchain from cache:"
  if tar xzf "${CACHED_TOOLCHAIN_ARCHIVE}" ; then
  echo "Done 'building' the toolchain."
+ echo "Cache unchanged."
  exit 0
  else
- echo "Could not extract cached toolchain archive, removing it and rebuilding from scratch."
+ echo
+ echo
+ echo
+ echo "Could not extract cached toolchain archive."
+ echo "This means the cache is broken and *should be removed*!"
+ echo "As Github Actions cannot update a cache, this will unnecessarily"
+ echo "slow down all future builds for this hash, until someone"
+ echo "resets the cache."
+ echo
+ echo
+ echo
  rm -f "${CACHED_TOOLCHAIN_ARCHIVE}"
  fi
  else
  echo "Cache at ${CACHED_TOOLCHAIN_ARCHIVE} does not exist."
  echo "Will rebuild toolchain from scratch, and save the result."
- echo "But first, getting rid of old, outdated caches. Current caches:"
- pushd "Cache/"
- ls -l
- # Travis preserves timestamps. Don't ask me why, but it does.
- # We can exploit this to get an easy approximation of recent-ness.
- # Our purging algorithm is simple: keep only the newest X entries.
- # Note that `find` doesn't easily support ordering by date,
- # and we control the filenames anyway.
- # shellcheck disable=SC2012
- ls -t | tail "-n+${KEEP_CACHE_COUNT}" | xargs -r rm -v
- echo "After deletion:"
- ls -l
- popd
  fi
+ echo "::group::Actually building Toolchain"
  fi
 popd
 
@@ -285,24 +261,20 @@ popd
 
 pushd "$DIR"
  if [ "${TRY_USE_LOCAL_TOOLCHAIN}" = "y" ] ; then
- echo "Caching toolchain:"
-
- if [ -z "${DEPS_HASH}" ] ; then
- echo "NOT SAVED, because hashing failed."
- echo "It's computed in the beginning; see there for the error message."
- elif [ -e "Cache/ToolchainLocal_${DEPS_HASH}.tar.gz" ] ; then
- # Note: This checks for *existence*. Initially we checked for
- # *readability*. If Travis borks permissions, there's not much we can do.
- echo "Cache exists but was not used?!"
- echo "Not touching cache then."
- else
- mkdir -p Cache/
- # We *most definitely* don't need debug symbols in the linker/compiler.
- # This cuts the uncompressed size from 1.2 GiB per Toolchain down to about 190 MiB.
- echo "Before: $(du -sh Local)"
- find Local/ -type f -executable ! -name '*.la' ! -name '*.sh' ! -name 'mk*' -exec strip {} +
- echo "After: $(du -sh Local)"
- tar czf "Cache/ToolchainLocal_${DEPS_HASH}.tar.gz" Local/
- fi
+ echo "::endgroup::"
+ echo "Building cache tar:"
+
+ rm -f "${CACHED_TOOLCHAIN_ARCHIVE}" # Just in case
+
+ # We *most definitely* don't need debug symbols in the linker/compiler.
+ # This cuts the uncompressed size from 1.2 GiB per Toolchain down to about 190 MiB.
+ echo "Stripping executables ..."
+ echo "Before: $(du -sh Local)"
+ find Local/ -type f -executable ! -name '*.la' ! -name '*.sh' ! -name 'mk*' -exec strip {} +
+ echo "After: $(du -sh Local)"
+ tar czf "${CACHED_TOOLCHAIN_ARCHIVE}" Local/
+
+ echo "Cache (after):"
+ ls -l Cache
  fi
 popd