build-experiment-tool/build-mapper.sh

#!/bin/bash
# Copyright (c) 2016 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Call this script as follows:
# ./build-mapper.sh /path/to/git/repo \
#                   /path/to/output/dir \
#                   [Number of commits before the current one to test]

export GIT_REPOSITORY=$(realpath $1)
export RESULT_DIRECTORY=$(realpath $2)
export NUMBER_OF_CLS=${3:-50}

FEATURE_DIR=$(realpath "$(dirname $0)/features/")

cd $GIT_REPOSITORY

# Store our previous state so that we can store it later.
previous_state=$(git rev-parse --abbrev-ref HEAD)

for ct in $(seq 1 $(($NUMBER_OF_CLS + 1))); do

  prev=$commit;
  commit=$(git log -1 --format='%h')
  echo "Working on $commit"
  if ! gclient sync -r $commit &> /dev/null; then
    echo 'gclient failed'
  fi

  echo '"'$commit'"' >> "$RESULT_DIRECTORY/config.feature"

  if [[ $ct != $(($NUMBER_OF_CLS + 1)) ]]; then
    for feature in $FEATURE_DIR/source/*; do
      feature_name=$(basename $feature)
      [ -x $feature ] && $feature \
        >> "${RESULT_DIRECTORY}/${feature_name}.feature" &
    done
  fi

  wait

  # Make directory and set args
  # Currently using release builds that are component builds.
  # Release builds use /much/ less storage (making it feasible to have a
  # large number of builds).
  # Component builds build somewhat faster, making it nice to have enabled.
  mkdir -p .out/Default
  echo 'is_debug=false' > .out/Default/args.gn
  echo 'is_component_build=true' >> .out/Default/args.gn
  gn gen .out/Default

  # Build, extract features, and copy out
  $(which time) -f '%e' -o $RESULT_DIRECTORY/build-time.feature -a \
    ninja -C .out/Default -j$(($(nproc) - 4))

  if [[ $ct == "1" ]]; then
    rm $RESULT_DIRECTORY/build-time.feature
  fi

  echo "copying $commit"
  cp -r .out "$RESULT_DIRECTORY/$commit.build"

  if [[ $ct != "1" ]]; then
    for feature in $FEATURE_DIR/unary/*; do
      feature_name=$(basename $feature)
      [ -x $feature ] && $feature $RESULT_DIRECTORY/$prev.build \
                      >> "${RESULT_DIRECTORY}/${feature_name}.feature" &
    done
    for feature in $FEATURE_DIR/unary/*; do
      feature_name=$(basename $feature)
      [ -x $feature ] || continue
      x=$($feature $RESULT_DIRECTORY/$prev.build)
      y=$($feature $RESULT_DIRECTORY/$commit.build)
      echo $(($x - $y)) \
        >> "${RESULT_DIRECTORY}/${feature_name}-change.feature" &
    done
    for feature in $FEATURE_DIR/binary/*; do
      feature_name=$(basename $feature)
      [ -x $feature ] && $feature $RESULT_DIRECTORY/$commit.build \
                                  $RESULT_DIRECTORY/$prev.build   \
                      >> "${RESULT_DIRECTORY}/${feature_name}.feature" &
    done
    wait
  fi

  # Go back a revision.
  if ! git checkout HEAD~1; then
    exit 1
  fi

  rm -rf $RESULT_DIRECTORY/$prev.build
done

# Restore us back to our start state
mv .out "$RESULT_DIRECTORY/$commit.build"
git checkout $previous_state

# Order the commits in time order.
for file in "$RESULT_DIRECTORY"/*.feature; do
  echo "Reversing $file"
  tac $file > "$RESULT_DIRECTORY/.tmp"
  echo "Moving $file"
  mv "$RESULT_DIRECTORY/.tmp" "$file"
done

exit 0