Add a flag to ConstConditionalSimplifier for removing asserts.

Change-Id: Ica31e595436181f013565516339ca1b97f6d5303
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/306305
Reviewed-by: Mayank Patke <fishythefish@google.com>
Reviewed-by: Ömer Ağacan <omersa@google.com>
Commit-Queue: Jackson Gardner <jacksongardner@google.com>

pkg/dart2wasm/README.md

@@ -38,7 +38,6 @@ where *options* include:
 | `--`[`no-`]`print-kernel`               | no      | Print IR for each function before compiling it.
 | `--`[`no-`]`print-wasm`                 | no      | Print Wasm instructions of each compiled function.
 | `--`[`no-`]`enable-asserts`             | no      | Enable assertions at runtime.
-| `--`[`no-`]`constant-branch-pruning`    | yes     | Avoid emitting code for dead branches of conditionals based on constants.
 | `--shared-memory-max-pages` *pagecount* |         | Max size of the imported memory buffer. If `--shared-import-memory` is specified, this must also be specified.
 | `--watch` *offset*                      |         | Print stack trace leading to the byte at offset *offset* in the `.wasm` output file. Can be specified multiple times.
 

pkg/dart2wasm/lib/compile.dart

@@ -58,7 +58,7 @@ Future<CompilerOutput?> compileToModule(compiler.CompilerOptions options,
   }
 
   final WasmTarget target =
-      WasmTarget(constantBranchPruning: options.constantBranchPruning);
+      WasmTarget(removeAsserts: !options.translatorOptions.enableAsserts);
   CompilerOptions compilerOptions = CompilerOptions()
     ..target = target
     ..sdkRoot = options.sdkPath

pkg/dart2wasm/lib/compiler_options.dart

@@ -22,7 +22,6 @@ class CompilerOptions {
   Map<fe.ExperimentalFlag, bool> feExperimentalFlags = const {};
   String? multiRootScheme;
   List<Uri> multiRoots = const [];
-  bool constantBranchPruning = true;
 
   factory CompilerOptions.defaultOptions() =>
       CompilerOptions(mainUri: Uri(), outputFile: '');

pkg/dart2wasm/lib/dart2wasm.dart

@@ -37,8 +37,6 @@ final List<Option> options = [
   Flag(
       "enable-asserts", (o, value) => o.translatorOptions.enableAsserts = value,
       defaultsTo: _d.translatorOptions.enableAsserts),
-  Flag("constant-branch-pruning", (o, value) => o.constantBranchPruning = value,
-      defaultsTo: _d.constantBranchPruning),
   Flag("omit-type-checks",
       (o, value) => o.translatorOptions.omitTypeChecks = value,
       defaultsTo: _d.translatorOptions.omitTypeChecks),

pkg/dart2wasm/lib/target.dart

@@ -35,9 +35,9 @@ import 'package:dart2wasm/records.dart' show RecordShape;
 import 'package:dart2wasm/transformers.dart' as wasmTrans;
 
 class WasmTarget extends Target {
-  WasmTarget({this.constantBranchPruning = true});
+  WasmTarget({this.removeAsserts = true});
 
-  bool constantBranchPruning;
+  bool removeAsserts;
   Class? _growableList;
   Class? _immutableList;
   Class? _wasmDefaultMap;
@@ -173,30 +173,30 @@ class WasmTarget extends Target {
       logger?.call("Transformed JS interop classes");
     }
 
-    if (constantBranchPruning) {
-      final reportError =
-          (LocatedMessage message, [List<LocatedMessage>? context]) {
-        diagnosticReporter.report(message.messageObject, message.charOffset,
-            message.length, message.uri);
-        if (context != null) {
-          for (final m in context) {
-            diagnosticReporter.report(
-                m.messageObject, m.charOffset, m.length, m.uri);
-          }
+    final reportError =
+        (LocatedMessage message, [List<LocatedMessage>? context]) {
+      diagnosticReporter.report(message.messageObject, message.charOffset,
+          message.length, message.uri);
+      if (context != null) {
+        for (final m in context) {
+          diagnosticReporter.report(
+              m.messageObject, m.charOffset, m.length, m.uri);
         }
-      };
+      }
+    };
+
+    ConstConditionalSimplifier(
+      dartLibrarySupport,
+      constantsBackend,
+      component,
+      reportError,
+      environmentDefines: environmentDefines ?? {},
+      evaluationMode: constantEvaluator.EvaluationMode.strong,
+      coreTypes: coreTypes,
+      classHierarchy: hierarchy,
+      removeAsserts: removeAsserts,
+    ).run();
 
-      ConstConditionalSimplifier(
-        dartLibrarySupport,
-        constantsBackend,
-        component,
-        reportError,
-        environmentDefines: environmentDefines ?? {},
-        evaluationMode: constantEvaluator.EvaluationMode.strong,
-        coreTypes: coreTypes,
-        classHierarchy: hierarchy,
-      ).run();
-    }
     transformMixins.transformLibraries(
         this, coreTypes, hierarchy, libraries, referenceFromIndex);
     logger?.call("Transformed mixin applications");

pkg/front_end/lib/src/fasta/kernel/const_conditional_simplifier.dart

@@ -16,6 +16,7 @@ class ConstConditionalSimplifier extends RemovingTransformer {
 
   late final TypeEnvironment _typeEnvironment;
   late final _ConstantEvaluator _constantEvaluator;
+  final bool _removeAsserts;
 
   ConstConditionalSimplifier(
     DartLibrarySupport librarySupport,
@@ -27,7 +28,8 @@ class ConstConditionalSimplifier extends RemovingTransformer {
     bool Function(TreeNode)? shouldNotInline,
     CoreTypes? coreTypes,
     ClassHierarchy? classHierarchy,
-  }) {
+    bool removeAsserts = false,
+  }) : _removeAsserts = removeAsserts {
     coreTypes ??= new CoreTypes(_component);
     classHierarchy ??= new ClassHierarchy(_component, coreTypes);
     _typeEnvironment = new TypeEnvironment(coreTypes, classHierarchy);
@@ -76,6 +78,35 @@ class ConstConditionalSimplifier extends RemovingTransformer {
       return node.otherwise ?? removalSentinel ?? new EmptyStatement();
     }
   }
+
+  @override
+  TreeNode visitAssertBlock(AssertBlock node, TreeNode? removalSentinel) {
+    if (_removeAsserts && removalSentinel != null) {
+      return removalSentinel;
+    } else {
+      return super.visitAssertBlock(node, removalSentinel);
+    }
+  }
+
+  @override
+  TreeNode visitAssertInitializer(
+      AssertInitializer node, TreeNode? removalSentinel) {
+    if (_removeAsserts && removalSentinel != null) {
+      return removalSentinel;
+    } else {
+      return super.visitAssertInitializer(node, removalSentinel);
+    }
+  }
+
+  @override
+  TreeNode visitAssertStatement(
+      AssertStatement node, TreeNode? removalSentinel) {
+    if (_removeAsserts && removalSentinel != null) {
+      return removalSentinel;
+    } else {
+      return super.visitAssertStatement(node, removalSentinel);
+    }
+  }
 }
 
 class _ConstantEvaluator extends TryConstantEvaluator {