[dart2wasm] Add -O/--optimization-level flag to dart compile wasm

We make the meaning of -O{0,1,2,3,4} to be similar to what dart2js has.
We also make the pkg/dart2wasm/tool/compile_benchmark accept the same flags.

Follow-up CLs will migrate Dart CI / Golem / flutter to use -O flags.

Change-Id: Id37476c596ec7483e633c7db9eec96438315e919
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/348165
Reviewed-by: Slava Egorov <[email protected]>

Author: mkustermann

pkg/dart2wasm/tool/compile_benchmark

@@ -8,6 +8,46 @@
 
 set -e
 
+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 "$BASH_SOURCE")"
+
+# Handle the case where dart-sdk/bin has been symlinked to.
+PROG_DIR="$(cd "${PROG_NAME%/*}" ; pwd -P)"
+SDK_DIR="$(cd "${PROG_DIR}/../../.." ; pwd -P)"
+
+# Locate build directory, containing executables, snapshots and platform dill.
+if [[ `uname` == 'Darwin' ]]; then
+  OUT_DIR="$SDK_DIR/xcodebuild"
+else
+  OUT_DIR="$SDK_DIR/out"
+fi
+DART_CONFIGURATION=${DART_CONFIGURATION:-ReleaseX64}
+BIN_DIR="$OUT_DIR/$DART_CONFIGURATION"
+
+BINARYEN="$BIN_DIR/wasm-opt"
+DART_AOT_RUNTIME="$BIN_DIR/dart_precompiled_runtime"
+SDK_ARG="--dart-sdk=$SDK_DIR"
+
+function find_flags {
+  echo -en "$(sed -n "/$1 =/,/end of $1/ p" $SDK_DIR/pkg/dartdev/lib/src/commands/compile.dart  | sed  '1d' | sed '$d' | tr '\n' ' ' | sed 's#\s\+# #g' | sed 's#^\s\+##' | sed 's#\s\+$##')"
+}
+# Use same flags as `dart compile exe`
+BINARYEN_FLAGS=($(find_flags 'binaryenFlags'))
+OPT_FLAGS_L0=($(find_flags 'optimizationLevel0Flags'))
+OPT_FLAGS_L1=($(find_flags 'optimizationLevel1Flags'))
+OPT_FLAGS_L2=($(find_flags 'optimizationLevel2Flags'))
+OPT_FLAGS_L3=($(find_flags 'optimizationLevel3Flags'))
+OPT_FLAGS_L4=($(find_flags 'optimizationLevel4Flags'))
+
 RUN_BINARYEN=1
 COMPILE_BENCHMARK_BASE_NAME=""
 PLATFORM_FILENAME="dart2wasm_platform.dill"
@@ -38,11 +78,43 @@ while [ $# -gt 0 ]; do
       shift
       ;;
 
+    -O0 | --optimization-level=0)
+      DART2WASM_ARGS+=(${OPT_FLAGS_L0[@]})
+      RUN_BINARYEN=0
+      shift
+      ;;
+
+    -O1 | --optimization-level=1)
+      DART2WASM_ARGS+=(${OPT_FLAGS_L1[@]})
+      RUN_BINARYEN=1
+      shift
+      ;;
+
+    -O2 | --optimization-level=2)
+      DART2WASM_ARGS+=(${OPT_FLAGS_L2[@]})
+      RUN_BINARYEN=1
+      shift
+      ;;
+
+    -O3 | --optimization-level=3)
+      DART2WASM_ARGS+=(${OPT_FLAGS_L3[@]})
+      RUN_BINARYEN=1
+      shift
+      ;;
+
+    -O4 | --optimization-level=4)
+      DART2WASM_ARGS+=(${OPT_FLAGS_L4[@]})
+      RUN_BINARYEN=1
+      shift
+      ;;
+
+    # TODO: Remove this deprecated flag
     --optimize)
       RUN_BINARYEN=1
       shift
       ;;
 
+    # TODO: Remove this deprecated flag
     --no-optimize)
       RUN_BINARYEN=0
       shift
@@ -83,40 +155,8 @@ if [ -z "$DART_FILE" -o -z "$WASM_FILE" ]; then
 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 "$BASH_SOURCE")"
-
-# Handle the case where dart-sdk/bin has been symlinked to.
-PROG_DIR="$(cd "${PROG_NAME%/*}" ; pwd -P)"
-SDK_DIR="$(cd "${PROG_DIR}/../../.." ; pwd -P)"
-
-# Use same binaryen flags as `dart compile exe`
-BINARYEN_FLAGS="$(sed -n '/binaryenFlags =/,/end of binaryenFlags/ p' $SDK_DIR/pkg/dartdev/lib/src/commands/compile.dart  | sed  '1d' | sed '$d' | tr '\n' ' ')"
-
-# Locate build directory, containing executables, snapshots and platform dill.
-if [[ `uname` == 'Darwin' ]]; then
-  OUT_DIR="$SDK_DIR/xcodebuild"
-else
-  OUT_DIR="$SDK_DIR/out"
-fi
-DART_CONFIGURATION=${DART_CONFIGURATION:-ReleaseX64}
-BIN_DIR="$OUT_DIR/$DART_CONFIGURATION"
-
-BINARYEN="$BIN_DIR/wasm-opt"
-DART_AOT_RUNTIME="$BIN_DIR/dart_precompiled_runtime"
-DART2WASM_AOT_SNAPSHOT="$BIN_DIR/$SNAPSHOT_NAME.snapshot"
-
 PLATFORM_ARG="--platform=$BIN_DIR/$PLATFORM_FILENAME"
-SDK_ARG="--dart-sdk=$SDK_DIR"
+DART2WASM_AOT_SNAPSHOT="$BIN_DIR/$SNAPSHOT_NAME.snapshot"
 
 function measure() {
   set +e

pkg/dartdev/lib/src/commands/compile.dart

@@ -19,28 +19,6 @@ import '../native_assets.dart';
 import '../sdk.dart';
 import '../utils.dart';
 
-// The unique place where we store dart2wasm binaryen flags.
-//
-// Other uses (e.g. in shell scripts) will grep in this file for the flags. So
-// please keep it as a simple multi-line string of flags.
-final List<String> binaryenFlags = '''
-  --all-features
-  --closed-world
-  --traps-never-happen
-  --type-unfinalizing
-  -O3
-  --type-ssa
-  --gufa
-  -O3
-  --type-merging
-  -O1
-  --type-finalizing
-''' // end of binaryenFlags
-    .split('\n')
-    .map((line) => line.trim())
-    .where((line) => line.isNotEmpty)
-    .toList();
-
 const int compileErrorExitCode = 64;
 
 class Option {
@@ -435,6 +413,57 @@ class CompileWasmCommand extends CompileSubcommandCommand {
   static const String help =
       'Compile Dart to a WebAssembly/WasmGC module (EXPERIMENTAL).';
 
+  // The unique place where we store various flags for dart2wasm & binaryen.
+  //
+  // Other uses (e.g. pkg/dart2wasm/tool/compile_benchmark) will grep in this
+  // file for the flags. So please keep the formatting.
+
+  final List<String> binaryenFlags = _flagList('''
+      --all-features
+      --closed-world
+      --traps-never-happen
+      --type-unfinalizing
+      -O3
+      --type-ssa
+      --gufa
+      -O3
+      --type-merging
+      -O1
+      --type-finalizing
+    '''); // end of binaryenFlags
+
+  final List<String> optimizationLevel0Flags = _flagList('''
+      --no-inlining
+    '''); // end of optimizationLevel0Flags
+
+  final List<String> optimizationLevel1Flags = _flagList('''
+      --inlining
+    '''); // end of optimizationLevel1Flags
+
+  final List<String> optimizationLevel2Flags = _flagList('''
+      --inlining
+      --minify
+    '''); // end of optimizationLevel2Flags
+
+  final List<String> optimizationLevel3Flags = _flagList('''
+      --inlining
+      --minify
+      --omit-implicit-checks
+    '''); // end of optimizationLevel3Flags
+
+  final List<String> optimizationLevel4Flags = _flagList('''
+      --inlining
+      --minify
+      --omit-implicit-checks
+      --omit-explicit-checks
+    '''); // end of optimizationLevel4Flags
+
+  static List<String> _flagList(String lines) => lines
+      .split('\n')
+      .map((line) => line.trim())
+      .where((line) => line.isNotEmpty)
+      .toList();
+
   CompileWasmCommand({bool verbose = false})
       : super(commandName, help, verbose, hidden: !verbose) {
     argParser
@@ -450,6 +479,7 @@ class CompileWasmCommand extends CompileSubcommandCommand {
         help: 'Generate minified output.',
         hide: !verbose,
       )
+      // TODO: Deprecate this flag.
       ..addFlag(
         'optimize',
         defaultsTo: true,
@@ -500,6 +530,16 @@ class CompileWasmCommand extends CompileSubcommandCommand {
         valueHelp: 'page count',
         hide: !verbose,
       )
+      ..addOption(
+        'optimization-level',
+        abbr: 'O',
+        help: 'Controls optimizations that can help reduce code-size and '
+            'improve performance of the generated code.',
+        allowed: ['0', '1', '2', '3', '4'],
+        defaultsTo: null, // TODO: Set this to '1'
+        valueHelp: 'level',
+        hide: !verbose,
+      )
       ..addOption(
         packagesOption.flag,
         abbr: packagesOption.abbr,
@@ -575,24 +615,42 @@ class CompileWasmCommand extends CompileSubcommandCommand {
       }
     }
 
+    final defaultOptimizationLevel = args['optimize'] ? '1' : '0';
+    final optimizationLevel =
+        int.parse(args['optimization-level'] ?? defaultOptimizationLevel);
+    final runWasmOpt = optimizationLevel >= 1;
+
     final dart2wasmCommand = [
       sdk.dartAotRuntime,
       sdk.dart2wasmSnapshot,
+
       '--libraries-spec=${sdk.librariesJson}',
       '--dart-sdk=$sdkPath',
       if (verbose) '--verbose',
       if (packages != null) '--packages=$packages',
-      if (args['enable-asserts']) '--enable-asserts',
       if (args['print-wasm']) '--print-wasm',
       if (args['print-kernel']) '--print-kernel',
-      if (args['omit-type-checks']) '--omit-type-checks',
-      if (args['name-section']) '--name-section',
-      if (args['minify']) '--minify',
+      if (args['enable-asserts']) '--enable-asserts',
+      for (final define in defines) '-D$define',
       if (maxPages != null) ...[
         '--import-shared-memory',
         '--shared-memory-max-pages=$maxPages',
       ],
-      for (final define in defines) '-D$define',
+
+      // First we pass flags based on the optimization level.
+      ...switch (optimizationLevel) {
+        0 => optimizationLevel0Flags,
+        1 => optimizationLevel1Flags,
+        2 => optimizationLevel2Flags,
+        3 => optimizationLevel3Flags,
+        4 => optimizationLevel4Flags,
+        _ => throw 'unreachable',
+      },
+      // Then we pass flags that were opted into explicitly.
+      if (args['omit-type-checks']) '--omit-type-checks',
+      if (args['name-section']) '--name-section',
+      if (args['minify']) '--minify',
+
       path.absolute(sourcePath),
       outputFile,
     ];
@@ -608,7 +666,7 @@ class CompileWasmCommand extends CompileSubcommandCommand {
       return compileErrorExitCode;
     }
 
-    if (args['optimize']) {
+    if (runWasmOpt) {
       final unoptFile = '$outputFileBasename.unopt.wasm';
       File(outputFile).renameSync(unoptFile);