dart/runtime/vm/debuginfo.h

// Copyright (c) 2012, 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.

#ifndef VM_DEBUGINFO_H_
#define VM_DEBUGINFO_H_

#include "platform/assert.h"
#include "platform/utils.h"
#include "vm/globals.h"

namespace dart {

// DebugInfo is used to generate minimal debug information containing code,
// symbols, and line numbers for generated code in the dart VM. This information
// can be used in two ways:
// - for debugging using a debugger
// - for generating information to be read by pprof to analyze Dart programs.
class DebugInfo {
 public:
  // A basic ByteBuffer which is growable and uses malloc/free.
  class ByteBuffer {
   public:
    ByteBuffer() : size_(0), capacity_(0), data_(NULL) { }
    ~ByteBuffer() {
      free(data_);
      size_ = 0;
      capacity_ = 0;
      data_ = NULL;
    }

    uint8_t at(int index) const {
      ASSERT(0 <= index);
      ASSERT(index < size_);
      ASSERT(size_ <= capacity_);
      return data_[index];
    }

    uint8_t* data() const { return data_; }
    void set_data(uint8_t* value) { data_ = value; }
    int size() const { return size_; }

    // Append an element.
    void Add(const uint8_t value) {
      Resize(size() + 1);
      data_[size() - 1] = value;
    }

   private:
    void Resize(int new_size) {
      if (new_size > capacity_) {
        int new_capacity = Utils::RoundUpToPowerOfTwo(new_size);
        uint8_t* new_data =
            reinterpret_cast<uint8_t*>(realloc(data_, new_capacity));
        ASSERT(new_data != NULL);
        data_ = new_data;
        capacity_ = new_capacity;
      }
      size_ = new_size;
    }

    int size_;
    int capacity_;
    uint8_t* data_;

    // Disallow assignment
    DISALLOW_COPY_AND_ASSIGN(ByteBuffer);
  };

  ~DebugInfo();

  // Add the code starting at pc.
  void AddCode(uword pc, intptr_t size);

  // Add symbol information for a region (includes the start and end symbol),
  // does not add the actual code.
  void AddCodeRegion(const char* name, uword pc, intptr_t size);

  // Write out all the debug information info the memory region.
  bool WriteToMemory(ByteBuffer* region);

  // Create a new debug information generator.
  static DebugInfo* NewGenerator();

  // Register this generated section with debuggger using the JIT interface.
  static void RegisterSection(const char* name,
                              uword entry_point,
                              intptr_t size);

  // Unregister all generated section from debuggger.
  static void UnregisterAllSections();

 private:
  void* handle_;
  DebugInfo();

  DISALLOW_COPY_AND_ASSIGN(DebugInfo);
};

}  // namespace dart

#endif  // VM_DEBUGINFO_H_