locate-symbol.dart

// Copyright (c) 2020, the Dart project authors.
//
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import 'dart:io';

class Symbol implements Comparable<Symbol> {
  final int address;
  final String name;
  Symbol(this.address, this.name);

  @override
  int compareTo(Symbol other) => this.address.compareTo(other.address);

  @override
  String toString() => 'sym(${name} at ${address.toRadixString(16)})';
}

void main(List<String> args) async {
  if (args.length != 3) {
    print('Usage: locate-symbol.dart <path-to-nm> <path-to-symbols-info> <pc>');
    exit(1);
  }
  final nmBinary = args[0];
  final debugInfo = args[1];
  final pc = int.tryParse(args[2], radix: 16);

  if (!File(nmBinary).existsSync()) {
    print('nm binary does not exist at ${nmBinary} path');
    exit(1);
  }
  if (!File(debugInfo).existsSync()) {
    print('symbols file does not exist at ${debugInfo} path');
    exit(1);
  }

  final result = await Process.run(nmBinary, [debugInfo]);
  if (result.exitCode != 0) {
    print(
        'Running ${nmBinary} ${debugInfo} failed with exit code ${result.exitCode}');
    print('STDOUT: ${result.stdout}\nSTDERR: ${result.stderr}\n');
    exit(1);
  }

  var symbols = (result.stdout as String)
      .split('\n')
      .map((s) => s.trim())
      .where((s) => s.isNotEmpty)
      .map((line) {
    final fields = line.split(' ');
    final addr = int.parse(fields[0], radix: 16);
    final name = fields[2];
    return Symbol(addr, name);
  }).toList(growable: false)
        ..sort();
  print('${pc.toRadixString(16)} belongs to ${binarySearch(symbols, pc)}');
}

Symbol binarySearch(List<Symbol> symbols, int pc) {
  var left = 0;
  var right = symbols.length;
  while (left < right) {
    var mid = (left + right) >> 1;
    var addr = symbols[mid].address;
    if (addr <= pc && pc < symbols[mid + 1].address) {
      return symbols[mid];
    }

    if (addr < pc) {
      left = mid;
    } else if (addr > pc) {
      right = mid;
    }
  }
  return null;
}