[CFE] Allow counting method calls when instrumenting

When instrumenting one can use "--count" to instrument counting method
calls instead of instrumenting to create a flame graph.

From that I can for instance see that `Reference.node` is called 6+ mio
times when compiling compile.dart.

Example run:
out/ReleaseX64/dart pkg/front_end/tool/flame/instrumenter.dart pkg/front_end/tool/_fasta/compile.dart --count
out/ReleaseX64/dart pkg/front_end/tool/_fasta/compile.dart.dill.instrumented.dill pkg/front_end/tool/_fasta/compile.dart

Change-Id: I583f4b53a474c3777bb059ea89d932607b7c23ad
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/298100
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>

Author: jensjoha

pkg/front_end/tool/flame/instrumenter.dart

@@ -26,8 +26,11 @@ Future<void> main(List<String> arguments) async {
 Future<void> _main(List<String> inputArguments, Directory tmpDir) async {
   List<String> candidates = [];
   List<String> arguments = [];
+  bool doCount = false;
   for (String arg in inputArguments) {
-    if (arg.startsWith("--candidates=")) {
+    if (arg == "--count") {
+      doCount = true;
+    } else if (arg.startsWith("--candidates=")) {
       candidates.add(arg.substring("--candidates=".length));
     } else {
       arguments.add(arg);
@@ -46,10 +49,14 @@ Future<void> _main(List<String> inputArguments, Directory tmpDir) async {
 
   print("Compiling the instrumentation library.");
   Uri instrumentationLibDill = tmpDir.uri.resolve("instrumenter.dill");
+  String libFilename = "instrumenter_lib.dart";
+  if (doCount) {
+    libFilename = "instrumenter_lib_counter.dart";
+  }
   await fasta_compile.main([
     "--omit-platform",
     "-o=${instrumentationLibDill.toFilePath()}",
-    Platform.script.resolve("instrumenter_lib.dart").toFilePath()
+    Platform.script.resolve(libFilename).toFilePath()
   ]);
   if (!File.fromUri(instrumentationLibDill).existsSync()) {
     throw "Instrumentation library didn't compile as expected.";
@@ -117,11 +124,15 @@ void addIfWanted(List<Procedure> output, List<Procedure> input,
   }
 }
 
-String getName(Procedure p) {
+String getName(Procedure p, {bool renameSetter = false}) {
+  String name = p.name.text;
+  if (renameSetter && p.isSetter) {
+    name = "set:$name";
+  }
   if (p.parent is Class) {
-    return "${(p.parent as Class).name}.${p.name.text}";
+    return "${(p.parent as Class).name}.$name";
   } else {
-    return p.name.text;
+    return name;
   }
 }
 
@@ -162,8 +173,9 @@ void initializeAndReport(
             instrumenterReport,
             new Arguments([
               new ListLiteral(procedures
-                  .map((p) => new StringLiteral(
-                      "${p.fileUri.pathSegments.last}|${getName(p)}"))
+                  .map(
+                      (p) => new StringLiteral("${p.fileUri.pathSegments.last}|"
+                          "${getName(p, renameSetter: true)}"))
                   .toList()),
               new BoolLiteral(reportCandidates),
             ])))),

pkg/front_end/tool/flame/instrumenter_lib_counter.dart

@@ -0,0 +1,73 @@
+// Copyright (c) 2023, 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.
+
+import "dart:typed_data";
+
+Stopwatch stopwatch = new Stopwatch();
+
+Uint32List counts = new Uint32List(0);
+
+void initialize(int count) {
+  counts = new Uint32List(count);
+  stopwatch.start();
+}
+
+@pragma("vm:prefer-inline")
+void enter(int i) {
+  counts[i]++;
+}
+
+@pragma("vm:prefer-inline")
+void exit(int i) {}
+
+void report(List<String> names, bool reportCandidates) {
+  List<NameWithCount> data = [];
+  for (int i = 0; i < counts.length; i++) {
+    int count = counts[i];
+    if (count < 10000) continue;
+    data.add(new NameWithCount(names[i], count));
+  }
+  data.sort((a, b) => a.count - b.count);
+  for (NameWithCount element in data) {
+    print("${_formatInt(element.count, 11)}: ${element.name}");
+  }
+}
+
+class NameWithCount {
+  final String name;
+  final int count;
+
+  NameWithCount(this.name, this.count);
+}
+
+String _formatInt(int input, int minLength) {
+  bool negative = false;
+  if (input < 0) {
+    negative = true;
+    input = -input;
+  }
+  String asString = "$input";
+  int length = asString.length;
+  int countSeparators = (length - 1) ~/ 3;
+  int outLength = length + countSeparators;
+  if (negative) outLength++;
+  StringBuffer sb = new StringBuffer();
+  if (outLength < minLength) {
+    sb.write(" " * (minLength - outLength));
+  }
+
+  if (negative) sb.write("-");
+  int end = length - (countSeparators * 3);
+  sb.write(asString.substring(0, end));
+  int begin = end;
+  end += 3;
+  while (end <= length) {
+    sb.write(",");
+    sb.write(asString.substring(begin, end));
+    begin = end;
+    end += 3;
+  }
+
+  return sb.toString();
+}