#!/usr/bin/env bash
# Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
# for details. All rights reserved. Use of this source code is governed by a
# BSD-style license that can be found in the LICENSE file.

# Script for generating AOT snapshot in two steps:
# - Compilation to kernel with additional AOT specific transformations.
# - Compilation of kernel into snapshot using gen_snapshot.

# Parse incoming arguments and extract the value of --packages option if any
# was passed. Split options (--xyz) and non-options into two separate arrays.
# All options will be passed to gen_snapshot, while --packages will be
# passed to the CFE (Common Front-End).

set -e

OPTIONS=()
GEN_KERNEL_OPTIONS=()
PACKAGES=
BUILD_ELF=0

ARGV=()
for arg in "$@"; do
  case $arg in
    --packages=*)
    PACKAGES="$arg"
    ;;
    --enable-asserts)
    GEN_KERNEL_OPTIONS+=("$arg")
    OPTIONS+=("$arg")
    ;;
    --tfa | \
    --no-tfa | \
    -D* )
    GEN_KERNEL_OPTIONS+=("$arg")
    ;;
    --build-elf)
    BUILD_ELF=1
    ;;
    --*)
    OPTIONS+=("$arg")
    ;;
    *)
    ARGV+=("$arg")
    ;;
  esac
done

if [ "${#ARGV[@]}" -ne 2 ]; then
    echo "Usage: $0 [options] <dart-source-file> <dart-aot-file>"
    echo ""
    echo "Dart AOT (ahead-of-time) compile Dart source code into native machine code."
    exit 1
fi

SOURCE_FILE="${ARGV[0]}"
SNAPSHOT_FILE="${ARGV[1]}"

if [ $BUILD_ELF -eq 1 ]; then
  GEN_SNAPSHOT_OPTION="--snapshot-kind=app-aot-assembly"
  GEN_SNAPSHOT_FILENAME="--assembly=${SNAPSHOT_FILE}.S"
else
  GEN_SNAPSHOT_OPTION="--snapshot-kind=app-aot-blobs"
  GEN_SNAPSHOT_FILENAME="--blobs_container_filename=${SNAPSHOT_FILE}"
fi

function follow_links() {
  file="$1"
  while [ -h "$file" ]; do
    # On Mac OS, readlink -f doesn't work.
    file="$(readlink "$file")"
  done
  echo "$file"
}

# Unlike $0, $BASH_SOURCE points to the absolute path of this file.
PROG_NAME="$(follow_links "$BASH_SOURCE")"

# Handle the case where dart-sdk/bin has been symlinked to.
BIN_DIR="$(cd "${PROG_NAME%/*}" ; pwd -P)"

SDK_DIR="$(cd "${BIN_DIR}/.." ; pwd -P)"

DART="$BIN_DIR/dart"
GEN_SNAPSHOT="$BIN_DIR/utils/gen_snapshot"

SNAPSHOT_DIR="$BIN_DIR/snapshots"
SNAPSHOT="$SNAPSHOT_DIR/gen_kernel.dart.snapshot"

# Step 1: Generate Kernel binary from the input Dart source.
"$DART"                                                                        \
     "${SNAPSHOT}"                                                             \
     --platform "${SDK_DIR}/lib/_internal/vm_platform_strong.dill"             \
     --aot                                                                     \
     -Ddart.vm.product=true                                                    \
     "${GEN_KERNEL_OPTIONS[@]}"                                                \
     $PACKAGES                                                                 \
     -o "$SNAPSHOT_FILE.dill"                                                  \
     "$SOURCE_FILE"

# Step 2: Generate snapshot from the Kernel binary.
"$GEN_SNAPSHOT"                                                                \
     "$GEN_SNAPSHOT_OPTION"                                                    \
     "$GEN_SNAPSHOT_FILENAME"                                                  \
     "${OPTIONS[@]}"                                                           \
     "$SNAPSHOT_FILE.dill"

# Step 3: Assemble the assembly file into an ELF object.
if [ $BUILD_ELF -eq 1 ]; then
    gcc -shared -o "$SNAPSHOT_FILE" "${SNAPSHOT_FILE}.S"
fi