src/hotspot/share/classfile/classPrinter.cpp

/*
 * Copyright (c) 2022, 2025, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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#include "classfile/classLoaderData.hpp"
#include "classfile/classLoaderDataGraph.hpp"
#include "classfile/classPrinter.hpp"
#include "memory/iterator.hpp"
#include "memory/resourceArea.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/klass.hpp"
#include "oops/method.hpp"
#include "oops/symbol.hpp"
#include "utilities/ostream.hpp"

class ClassPrinter::KlassPrintClosure : public LockedClassesDo {
  const char* _class_name_pattern;
  const char* _method_name_pattern;
  const char* _method_signature_pattern;
  bool _always_print_class_name;
  int _flags;
  outputStream* _st;
  int _num;
  bool _has_printed_methods;
public:
  KlassPrintClosure(const char* class_name_pattern,
                    const char* method_name_pattern,
                    const char* method_signature_pattern,
                    bool always_print_class_name,
                    int flags, outputStream* st)
    : _class_name_pattern(class_name_pattern),
      _method_name_pattern(method_name_pattern),
      _method_signature_pattern(method_signature_pattern),
      _always_print_class_name(always_print_class_name),
      _flags(flags), _st(st), _num(0), _has_printed_methods(false)
  {
    if (has_mode(_flags, PRINT_METHOD_HANDLE)) {
      _flags |= (PRINT_METHOD_NAME | PRINT_BYTECODE);
    }
    if (has_mode(_flags, PRINT_DYNAMIC)) {
      _flags |= (PRINT_METHOD_NAME | PRINT_BYTECODE);
    }
    if (has_mode(_flags, PRINT_BYTECODE_ADDR)) {
      _flags |= (PRINT_METHOD_NAME | PRINT_BYTECODE);
    }
    if (has_mode(_flags, PRINT_BYTECODE)) {
      _flags |= (PRINT_METHOD_NAME);
    }
  }

  virtual void do_klass(Klass* k) {
    if (!k->is_instance_klass()) {
      return;
    }
    print_instance_klass(InstanceKlass::cast(k));
  }

  static bool match(const char* pattern, Symbol* sym) {
    return (pattern == nullptr || sym->is_star_match(pattern));
  }

  void print_klass_name(InstanceKlass* ik) {
    _st->print("[%3d] " INTPTR_FORMAT " class %s ", _num++, p2i(ik), ik->name()->as_C_string());
    ik->class_loader_data()->print_value_on(_st);
    _st->cr();
  }

  void print_instance_klass(InstanceKlass* ik) {
    if (ik->is_loaded() && ik->name()->is_star_match(_class_name_pattern)) {
      ResourceMark rm;
      if (_has_printed_methods) {
        // We have printed some methods in the previous class.
        // Print a new line to separate the two classes
        _st->cr();
      }
      _has_printed_methods = false;
      if (_always_print_class_name) {
        print_klass_name(ik);
      }

      if (has_mode(_flags, ClassPrinter::PRINT_METHOD_NAME)) {
        bool print_codes = has_mode(_flags, ClassPrinter::PRINT_BYTECODE);
        int len = ik->methods()->length();
        int num_methods_printed = 0;

        for (int index = 0; index < len; index++) {
          Method* m = ik->methods()->at(index);
          if (match(_method_name_pattern, m->name()) &&
              match(_method_signature_pattern, m->signature())) {
            if (print_codes && num_methods_printed++ > 0) {
              _st->cr();
            }

            if (_has_printed_methods == false) {
              if (!_always_print_class_name) {
                print_klass_name(ik);
              }
              _has_printed_methods = true;
            }
            print_method(m);
          }
        }
      }
    }
  }

  void print_method(Method* m) {
    bool print_codes = has_mode(_flags, ClassPrinter::PRINT_BYTECODE);
    _st->print_cr(INTPTR_FORMAT " %smethod %s : %s", p2i(m),
                  m->is_static() ? "static " : "",
                  m->name()->as_C_string(), m->signature()->as_C_string());
    if (print_codes) {
      m->print_codes_on(_st, _flags);
    }
  }
};

void ClassPrinter::print_flags_help(outputStream* os) {
  os->print_cr("flags (bitmask):");
  os->print_cr("   0x%02x  - print names of methods", PRINT_METHOD_NAME);
  os->print_cr("   0x%02x  - print bytecodes", PRINT_BYTECODE);
  os->print_cr("   0x%02x  - print the address of bytecodes", PRINT_BYTECODE_ADDR);
  os->print_cr("   0x%02x  - print info for invokedynamic", PRINT_DYNAMIC);
  os->print_cr("   0x%02x  - print info for invokehandle",  PRINT_METHOD_HANDLE);
  os->cr();
}

void ClassPrinter::print_classes(const char* class_name_pattern, int flags, outputStream* os) {
  KlassPrintClosure closure(class_name_pattern, nullptr, nullptr, true, flags, os);
  ClassLoaderDataGraph::classes_do(&closure);
}

void ClassPrinter::print_methods(const char* class_name_pattern,
                                 const char* method_pattern, int flags, outputStream* os) {
  ResourceMark rm;
  const char* method_name_pattern;
  const char* method_signature_pattern;

  const char* colon = strchr(method_pattern, ':');
  if (colon == nullptr) {
    method_name_pattern = method_pattern;
    method_signature_pattern = nullptr;
  } else {
    ptrdiff_t name_pat_len = colon - method_pattern;
    assert(name_pat_len >= 0, "sanity");
    char* buf = NEW_RESOURCE_ARRAY(char, name_pat_len + 1);
    strncpy(buf, method_pattern, name_pat_len);
    buf[name_pat_len] = 0;

    method_name_pattern = buf;
    method_signature_pattern = colon + 1;
  }

  KlassPrintClosure closure(class_name_pattern, method_name_pattern, method_signature_pattern,
                            false, flags | PRINT_METHOD_NAME, os);
  ClassLoaderDataGraph::classes_do(&closure);
}