debugallocator.hh

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_DEBUG_ALLOCATOR_HH
#define DUNE_DEBUG_ALLOCATOR_HH
 
#if __has_include(<sys/mman.h>)
 
#include <sys/mman.h>
#define HAVE_SYS_MMAN_H 1
#define HAVE_MPROTECT 1
 
#include <exception>
#include <typeinfo>
#include <vector>
#include <iostream>
#include <cstring>
#include <cstdint>
#include <cstdlib>
#include <new>
 
#include "mallocallocator.hh"
 
namespace Dune
{
 
#ifndef DOXYGEN // hide implementation details from doxygen
  namespace DebugMemory
  {
 
    extern const std::ptrdiff_t page_size;
 
    struct AllocationManager
    {
      typedef std::size_t size_type;
      typedef std::ptrdiff_t difference_type;
      typedef void* pointer;
 
    protected:
      static void allocation_error(const char* msg);
 
      struct AllocationInfo;
      friend struct AllocationInfo;
 
#define ALLOCATION_ASSERT(A) { if (!(A))                            \
                               { allocation_error("Assertion " # A " failed");\
                               }\
};
 
      struct AllocationInfo
      {
        AllocationInfo(const std::type_info & t) : type(&t) {}
        const std::type_info * type;
 
        pointer page_ptr;
        pointer ptr;
        size_type pages;
        size_type capacity;
        size_type size;
        bool not_free;
      };
 
      typedef MallocAllocator<AllocationInfo> Alloc;
      typedef std::vector<AllocationInfo, Alloc> AllocationList;
      AllocationList allocation_list;
 
    private:
      void memprotect([[maybe_unused]] void* from,
                      [[maybe_unused]] difference_type len,
                      [[maybe_unused]] int prot)
      {
#if HAVE_SYS_MMAN_H && HAVE_MPROTECT
        int result = mprotect(from, len, prot);
        if (result == -1)
        {
 
          std::cerr << "ERROR: (" << result << ": " << strerror(result) << ")" << std::endl;
          std::cerr << " Failed to ";
          if (prot == PROT_NONE)
            std::cerr << "protect ";
          else
            std::cerr << "unprotect ";
          std::cerr << "memory range: "
                    << from << ", "
                    << static_cast<void*>(
            static_cast<char*>(from) + len)
                    << std::endl;
          abort();
        }
#else
        std::cerr << "WARNING: memory protection not available" << std::endl;
#endif
      }
 
    public:
 
      ~AllocationManager ()
      {
        AllocationList::iterator it;
        bool error = false;
        for (it=allocation_list.begin(); it!=allocation_list.end(); it++)
        {
          if (it->not_free)
          {
            std::cerr << "ERROR: found memory chunk still in use: " <<
            it->capacity << " bytes at " << it->ptr << std::endl;
            error = true;
          }
          munmap(it->page_ptr, it->pages * page_size);
        }
        if (error)
          allocation_error("lost allocations");
      }
 
      template<typename T>
      T* allocate(size_type n)
      {
        // setup chunk info
        AllocationInfo ai(typeid(T));
        ai.size = n;
        ai.capacity = n * sizeof(T);
        ai.pages = (ai.capacity) / page_size + 2;
        ai.not_free = true;
        size_type overlap = ai.capacity % page_size;
        ai.page_ptr = mmap(NULL, ai.pages * page_size,
                           PROT_READ | PROT_WRITE,
#ifdef __APPLE__
                           MAP_ANON | MAP_PRIVATE,
#else
                           MAP_ANONYMOUS | MAP_PRIVATE,
#endif
                           -1, 0);
        if (MAP_FAILED == ai.page_ptr)
        {
          throw std::bad_alloc();
        }
        ai.ptr = static_cast<char*>(ai.page_ptr) + page_size - overlap;
        // write protect memory behind the actual data
        memprotect(static_cast<char*>(ai.page_ptr) + (ai.pages-1) * page_size,
                   page_size,
                   PROT_NONE);
        // remember the chunk
        allocation_list.push_back(ai);
        // return the ptr
        return static_cast<T*>(ai.ptr);
      }
 
      template<typename T>
      void deallocate(T* ptr, size_type n = 0) noexcept
      {
        // compute page address
        void* page_ptr =
          static_cast<void*>(
            (char*)(ptr) - ((std::uintptr_t)(ptr) % page_size));
        // search list
        AllocationList::iterator it;
        unsigned int i = 0;
        for (it=allocation_list.begin(); it!=allocation_list.end(); it++, i++)
        {
          if (it->page_ptr == page_ptr)
          {
            // std::cout << "found memory_block in allocation " << i << std::endl;
            // sanity checks
            if (n != 0)
              ALLOCATION_ASSERT(n == it->size);
            ALLOCATION_ASSERT(ptr == it->ptr);
            ALLOCATION_ASSERT(true == it->not_free);
            ALLOCATION_ASSERT(typeid(T) == *(it->type));
            // free memory
            it->not_free = false;
#if DEBUG_ALLOCATOR_KEEP
            // write protect old memory
            memprotect(it->page_ptr,
                       (it->pages) * page_size,
                       PROT_NONE);
#else
            // unprotect old memory
            memprotect(it->page_ptr,
                       (it->pages) * page_size,
                       PROT_READ | PROT_WRITE);
            munmap(it->page_ptr, it->pages * page_size);
            // remove chunk info
            allocation_list.erase(it);
#endif
            return;
          }
        }
        allocation_error("memory block not found");
      }
    };
#undef ALLOCATION_ASSERT
 
    extern AllocationManager alloc_man;
  }   // end namespace DebugMemory
#endif // DOXYGEN
 
  template<class T>
  class DebugAllocator;
 
  // specialize for void
  template <>
  class DebugAllocator<void> {
  public:
    typedef void* pointer;
    typedef const void* const_pointer;
    // reference to void members are impossible.
    typedef void value_type;
    template <class U> struct rebind {
      typedef DebugAllocator<U> other;
    };
  };
 
  // actual implementation
  template <class T>
  class DebugAllocator {
  public:
    typedef std::size_t size_type;
    typedef std::ptrdiff_t difference_type;
    typedef T* pointer;
    typedef const T* const_pointer;
    typedef T& reference;
    typedef const T& const_reference;
    typedef T value_type;
    template <class U> struct rebind {
      typedef DebugAllocator<U> other;
    };
 
    DebugAllocator() noexcept {}
    template <class U>
    DebugAllocator(const DebugAllocator<U>&) noexcept {}
    ~DebugAllocator() noexcept {}
 
    pointer address(reference x) const
    {
      return &x;
    }
    const_pointer address(const_reference x) const
    {
      return &x;
    }
 
    pointer allocate(size_type n,
                     [[maybe_unused]] DebugAllocator<void>::const_pointer hint = 0)
    {
      return DebugMemory::alloc_man.allocate<T>(n);
    }
 
    void deallocate(pointer p, size_type n)
    {
      DebugMemory::alloc_man.deallocate<T>(p,n);
    }
 
    size_type max_size() const noexcept
    {
      return size_type(-1) / sizeof(T);
    }
 
    void construct(pointer p, const T& val)
    {
      ::new((void*)p)T(val);
    }
 
    template<typename ... Args>
    void construct(pointer p, Args&&... args)
    {
      ::new((void *)p)T(std::forward<Args>(args) ...);
    }
 
    void destroy(pointer p)
    {
      p->~T();
    }
  };
 
  template<class T>
  constexpr bool
  operator==(const DebugAllocator<T> &, const DebugAllocator<T> &)
  {
    return true;
  }
 
  template<class T>
  constexpr bool
  operator!=(const DebugAllocator<T> &, const DebugAllocator<T> &)
  {
    return false;
  }
}
 
#ifdef DEBUG_NEW_DELETE
void * operator new(size_t size)
{
  // try to allocate size bytes
  void *p = Dune::DebugMemory::alloc_man.allocate<char>(size);
#if DEBUG_NEW_DELETE > 2
  std::cout << "NEW " << size
            << " -> " << p
            << std::endl;
#endif
  return p;
}
 
void operator delete(void * p) noexcept
{
#if DEBUG_NEW_DELETE > 2
  std::cout << "FREE " << p << std::endl;
#endif
  Dune::DebugMemory::alloc_man.deallocate<char>(static_cast<char*>(p));
}
 
void operator delete(void * p, size_t size) noexcept
{
#if DEBUG_NEW_DELETE > 2
  std::cout << "FREE " << p << std::endl;
#endif
  Dune::DebugMemory::alloc_man.deallocate<char>(static_cast<char*>(p), size);
}
 
#endif // DEBUG_NEW_DELETE
 
#endif // __has_include(<sys/mman.h>)
 
#endif // DUNE_DEBUG_ALLOCATOR_HH