Add command line options to rank_stacks

pkg/compiler/tool/status_files/rank_stacks.dart

Index: pkg/compiler/tool/status_files/rank_stacks.dart
diff --git a/pkg/compiler/tool/status_files/rank_stacks.dart b/pkg/compiler/tool/status_files/rank_stacks.dart
index 31345e037b721d68eb82ca505a6f4a586e4aabe7..db40cbb48868b4a9e6cc160e0eaca0a8ed94a7dd 100644
--- a/pkg/compiler/tool/status_files/rank_stacks.dart
+++ b/pkg/compiler/tool/status_files/rank_stacks.dart
@@ -21,33 +21,59 @@ import 'dart:io';
 import 'log_parser.dart';
 import 'record.dart';
 
-// TODO(sra): Allow command-line setting of these parameters.
-const STACK_PRINT_LENGTH = 12;
-const HOW_MANY_STACKS = 30;
+const DEFAULT_STACK_PRINT_LENGTH = 12;
+const DEFAULT_HOW_MANY_STACKS = 20;
+const USAGE = """
+dart rank_stacks.dart [options] test-log
+
+--stacks=N, -sN: Print highest ranking N stacks (0 means all stacks).
+    Defaults to top ${DEFAULT_HOW_MANY_STACKS} stacks.
+
+--length=N, -lN: Print N frames of each stack.
+    Defaults to ${DEFAULT_STACK_PRINT_LENGTH} frames.
+""";
+
+int stackPrintLength = DEFAULT_STACK_PRINT_LENGTH;
+int howManyStacks = DEFAULT_HOW_MANY_STACKS;
+
+void die(String why) {
+  print(why);
+  print('Usage:\n${USAGE}');
+  exit(1);
+}
 
 main(args) {
   String text;
 
+  // Parse options.
   for (String arg in args) {
-    // Parse options.
+    Match m;
+    if ((m = new RegExp(r'(--stacks=|-s)(\d+)$').matchAsPrefix(arg)) != null) {

[Siggi Cherem (dart-lang), 2017/08/26 02:09:00]

consider using the `args` package?

[sra1, 2017/08/29 19:53:03]

Done.

+      howManyStacks = int.parse(m.group(2));
+      continue;
+    }
+
+    if ((m = new RegExp(r'(--length=|-l)(\d+)$').matchAsPrefix(arg)) != null) {
+      stackPrintLength = int.parse(m.group(2));
+      continue;
+    }
+
+    if (arg.startsWith('-')) die("Unknown option '$arg'");
 
     if (text == null) {
       var uri = Uri.base.resolve(arg);
       var file = new File.fromUri(uri);
       if (!file.existsSync()) {
-        print('File not found: $file.');
-        exit(1);
+        die('File not found: $file.');
       }
       text = file.readAsStringSync();
     } else {
-      print("Extra file argument '$arg'.");
-      exit(1);
+      die("Extra file argument '$arg'.");
     }
   }
 
   if (text == null) {
-    print('No input file.');
-    exit(1);
+    die('No input file.');
   }
 
   var records = parse(text);
@@ -58,7 +84,7 @@ main(args) {
 
   var leaves = trieLeaves(trie).toList();
   leaves.sort((a, b) => b.length.compareTo(a.length));
-  for (var leaf in leaves.take(HOW_MANY_STACKS)) {
+  for (var leaf in howManyStacks == 0 ? leaves : leaves.take(howManyStacks)) {
     print('');
     var examples = leaf.members.map((r) => r.fullReason).toSet().toList();
     examples.sort();
@@ -71,7 +97,7 @@ main(args) {
       print('${countAligned}${indentedExample}');
     }
 
-    for (var line in leaf.members.first.stack.take(STACK_PRINT_LENGTH)) {
+    for (var line in leaf.members.first.stack.take(stackPrintLength)) {
       print('  $line');
     }
   }