[kernel/vm] Address follow-up review comments for bytecode generation

Change-Id: Ifa9dd128ef7179ec521c893ac567b0f81ba5e306
Reviewed-on: https://dart-review.googlesource.com/53120
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Peter von der Ahé <ahe@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>

pkg/front_end/tool/_fasta/compile_platform.dart

@@ -11,7 +11,7 @@ import 'dart:io' show File, Platform, exitCode;
 import 'package:compiler/src/kernel/dart2js_target.dart' show Dart2jsTarget;
 
 import 'package:vm/bytecode/gen_bytecode.dart'
-    show generateBytecode, kEnableKernelBytecodeForPlatform;
+    show generateBytecode, isKernelBytecodeEnabledForPlatform;
 
 import 'package:vm/target/dart_runner.dart' show DartRunnerTarget;
 
@@ -89,7 +89,7 @@ Future compilePlatformInternal(
   new File.fromUri(outlineOutput).writeAsBytesSync(result.summary);
   c.options.ticker.logMs("Wrote outline to ${outlineOutput.toFilePath()}");
 
-  if (kEnableKernelBytecodeForPlatform) {
+  if (isKernelBytecodeEnabledForPlatform) {
     generateBytecode(result.component, strongMode: c.options.strongMode);
   }
 

pkg/vm/bin/gen_kernel.dart

@@ -14,7 +14,7 @@ import 'package:kernel/target/targets.dart' show TargetFlags;
 import 'package:kernel/target/vm.dart' show VmTarget;
 import 'package:kernel/text/ast_to_text.dart'
     show globalDebuggingNames, NameSystem;
-import 'package:vm/bytecode/gen_bytecode.dart' show kEnableKernelBytecode;
+import 'package:vm/bytecode/gen_bytecode.dart' show isKernelBytecodeEnabled;
 import 'package:vm/kernel_front_end.dart' show compileToKernel, ErrorDetector;
 
 final ArgParser _argParser = new ArgParser(allowTrailingOptions: true)
@@ -39,7 +39,7 @@ final ArgParser _argParser = new ArgParser(allowTrailingOptions: true)
   ..addMultiOption('entry-points',
       help: 'Path to JSON file with the list of entry points')
   ..addFlag('gen-bytecode',
-      help: 'Generate bytecode', defaultsTo: kEnableKernelBytecode);
+      help: 'Generate bytecode', defaultsTo: isKernelBytecodeEnabled);
 
 final String _usage = '''
 Usage: dart pkg/vm/bin/gen_kernel.dart --platform vm_platform_strong.dill [options] input.dart

pkg/vm/bin/run_binary_size_analysis.dart

@@ -122,7 +122,7 @@ void addSymbol(Map<String, dynamic> root, String path, String name, int size) {
   node['t'] = symbolTypeGlobalText;
   node['value'] = size;
   depth += 2;
-  root['maxDepth'] = max(root['maxDepth'], depth);
+  root['maxDepth'] = max<int>(root['maxDepth'], depth);
 }
 
 /// Convert all children entries from maps to lists.

pkg/vm/lib/bytecode/constant_pool.dart

@@ -397,8 +397,8 @@ class ConstantArgDesc extends ConstantPoolEntry {
       'ArgDesc num-args $numArguments, num-type-args $numTypeArgs, names $argNames';
 
   @override
-  int get hashCode =>
-      (numArguments * 31 + numTypeArgs) * 31 + listHashCode(argNames);
+  int get hashCode => _combineHashes(
+      _combineHashes(numArguments, numTypeArgs), listHashCode(argNames));
 
   @override
   bool operator ==(other) =>
@@ -770,9 +770,9 @@ class ConstantInstance extends ConstantPoolEntry {
               new MapEntry(fieldRef.asField.name.name, valueIndex))}';
 
   @override
-  int get hashCode =>
-      (classNode.hashCode * 31 + _typeArgumentsConstantIndex) * 31 +
-      mapHashCode(_fieldValues);
+  int get hashCode => _combineHashes(
+      _combineHashes(classNode.hashCode, _typeArgumentsConstantIndex),
+      mapHashCode(_fieldValues));
 
   @override
   bool operator ==(other) =>
@@ -844,7 +844,7 @@ class ConstantTypeArgumentsForInstanceAllocation extends ConstantPoolEntry {
 
   @override
   int get hashCode =>
-      instantiatingClass.hashCode * 31 + _typeArgumentsConstantIndex;
+      _combineHashes(instantiatingClass.hashCode, _typeArgumentsConstantIndex);
 
   @override
   bool operator ==(other) =>
@@ -893,3 +893,6 @@ class ConstantPool {
     return sb.toString();
   }
 }
+
+int _combineHashes(int hash1, int hash2) =>
+    (((hash1 * 31) & 0x3fffffff) + hash2) & 0x3fffffff;

pkg/vm/lib/bytecode/gen_bytecode.dart

@@ -20,12 +20,12 @@ import 'package:vm/bytecode/local_vars.dart' show LocalVariables;
 import 'package:vm/metadata/bytecode.dart';
 
 /// Flag to toggle generation of bytecode in kernel files.
-const bool kEnableKernelBytecode = false;
+const bool isKernelBytecodeEnabled = false;
 
 /// Flag to toggle generation of bytecode in platform kernel files.
-const bool kEnableKernelBytecodeForPlatform = kEnableKernelBytecode;
+const bool isKernelBytecodeEnabledForPlatform = isKernelBytecodeEnabled;
 
-const bool kTrace = false;
+const bool isTraceEnabled = false;
 
 void generateBytecode(Component component, {bool strongMode: true}) {
   final coreTypes = new CoreTypes(component);
@@ -114,7 +114,7 @@ class BytecodeGenerator extends RecursiveVisitor<Null> {
         end(node);
       }
     } on UnsupportedOperationError catch (e) {
-      if (kTrace) {
+      if (isTraceEnabled) {
         print('Unable to generate bytecode for $node: $e');
       }
     }
@@ -382,7 +382,7 @@ class BytecodeGenerator extends RecursiveVisitor<Null> {
     enclosingMember = null;
     enclosingClass = null;
     metadata.mapping[node] = new BytecodeMetadata(asm.bytecode, cp);
-    if (kTrace) {
+    if (isTraceEnabled) {
       print('Generated bytecode for $node');
     }
   }