#!/usr/bin/env bash
# Copyright (c) 2017, 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 using Dart 2 pipeline: Fasta with
# strong mode enabled, AOT specific Kernel-to-Kernel transformations and
# Dart VM precompiler with strong mode semantics and reified generics.

# 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 Fasta.

set -e

function follow_links() {
  local 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.
CUR_DIR="$(cd "${PROG_NAME%/*}" ; pwd -P)"

SDK_DIR="$CUR_DIR/../../.."

. "$CUR_DIR/shared_functions.sh"

OPTIONS=()
GEN_KERNEL_OPTIONS=()
PACKAGES=
BUILD_ASM=0

ARGV=()
for arg in "$@"; do
  case $arg in
    --packages=sdk)
    PACKAGES="$SDK_DIR/.dart_tool/package_config.json"
    ;;
    --packages=*)
    PACKAGES="$arg"
    ;;
    --enable-asserts | \
    --sound-null-safety | \
    --no-sound-null-safety | \
    --enable-experiment=*)
    GEN_KERNEL_OPTIONS+=("$arg")
    OPTIONS+=("$arg")
    ;;
    --tfa | \
    --no-tfa | \
    --protobuf-tree-shaker-v2 | \
    --minimal-kernel | \
    --no-embed-sources | \
    --dynamic-interface=* | \
    -D* )
    GEN_KERNEL_OPTIONS+=("$arg")
    ;;
    --build-assembly)
    BUILD_ASM=1
    ;;
    -v*)
    set -x
    ;;
    --*)
    OPTIONS+=("$arg")
    ;;
    *)
    ARGV+=("$arg")
    ;;
  esac
done

if [ "${#ARGV[@]}" -ne 2 ]; then
    echo "Usage: $0 [options] <source> <snapshot>"
    exit 1
fi

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

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

if [[ `uname` == 'Darwin' ]]; then
  OUT_DIR="$SDK_DIR/xcodebuild"
else
  OUT_DIR="$SDK_DIR/out"
fi

HOST_ARCH="$(host_arch)"

export DART_CONFIGURATION=${DART_CONFIGURATION:-Release$HOST_ARCH}
TARGET_ARCH="$(parse_target_arch "$DART_CONFIGURATION")"
BUILD_DIR="$OUT_DIR/$DART_CONFIGURATION"
if [ ! -d "$BUILD_DIR" ]; then
  echo "$BUILD_DIR is not a directory" >&2
  exit 1
fi

function find_dart {
  local tools_dart="${SDK_DIR}/tools/sdks/dart-sdk/bin/dart"
  if [ -f "$tools_dart" ]; then
    echo "$tools_dart"
  else
    local host_dart=""
    if is_cross_compiled "$HOST_ARCH" "$TARGET_ARCH"; then
      host_dart="$OUT_DIR/Release$HOST_ARCH/dart"
    else
      host_dart="$BUILD_DIR/dart"
    fi
    if [ ! -f "$host_dart" ]; then
      echo "Cannot find dart at either $tools_dart or $host_dart" >&2
      exit 1
    fi
    echo "$host_dart"
  fi
}

DART="$(find_dart)"

function gen_kernel() {
  if [[ "$DART_GN_ARGS" == *"precompile_tools=true"* ]]; then
    # Precompile gen_kernel to an AOT app.
    ninja -C "$BUILD_DIR" gen_kernel.exe
    "$BUILD_DIR/gen_kernel.exe" $@
  else
    $DART ${DART_VM_FLAGS} "${SDK_DIR}/pkg/vm/bin/gen_kernel.dart" $@
  fi
}

# Step 1: Generate Kernel binary from the input Dart source.
gen_kernel --platform "${BUILD_DIR}/vm_platform.dill"                   \
     --aot                                                                     \
     "${GEN_KERNEL_OPTIONS[@]}"                                                \
     $PACKAGES                                                                 \
     -o "$SNAPSHOT_FILE.dill"                                                  \
     "$SOURCE_FILE"

GEN_SNAPSHOT="gen_snapshot"
# If the target architecture differs from the host architecture, use
# gen_snapshot for the host architecture for cross compilation, which is
# denoted by an X between the build mode and the architecture name,
# e.g., ReleaseXARM64 on X64.
if [[ "$DART_CONFIGURATION" =~ (Debug|Release|Product)X[^6] ]] && \
      is_cross_compiled "$HOST_ARCH" "$TARGET_ARCH"; then
  case "$HOST_ARCH" in
    "X64")
    GEN_SNAPSHOT="clang_x64/${GEN_SNAPSHOT}"
    ;;
    "ARM64")
    GEN_SNAPSHOT="clang_arm64/${GEN_SNAPSHOT}"
    ;;
    *)
    echo "Unexpected host architecture $HOST_ARCH for cross compilation" >&2
    exit 1
    ;;
  esac
fi

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

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