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IgProfBuffer Class Reference

Utility class for implementing private heap and hashed data structures. More...

#include <IgTools/IgProf/src/IgProfBuffer.h>

Inheritance diagram for IgProfBuffer:

List of all members.

Protected Member Functions
template<class T>
T *	allocate (void)
void *	allocateRaw (size_t size)
void *	allocateSpace (size_t amount)
	IgProfBuffer (void)
	Initialise a buffer.
void	unallocateRaw (void *p, size_t size)
	~IgProfBuffer (void)
Static Protected Member Functions
static uint32_t	hash (uintptr_t key)
Private Member Functions
void	allocatePool (void)
	IgProfBuffer (IgProfBuffer &)
IgProfBuffer &	operator= (IgProfBuffer &)
Private Attributes
char *	freeend_
char *	freestart_
void **	poolcur_
void **	poolfirst_

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Detailed Description

Utility class for implementing private heap and hashed data structures.

Definition at line 10 of file IgProfBuffer.h.

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Constructor & Destructor Documentation

IgProfBuffer::IgProfBuffer

(

void

)

[protected]

Initialise a buffer.

Definition at line 13 of file IgProfBuffer.cc.

References allocateRaw(), freeend_, freestart_, MEM_POOL_SIZE, poolcur_, and poolfirst_.

  : poolfirst_(0),
    poolcur_(0),
    freestart_(0),
    freeend_(0)
{
  // Get the first pool and initialise the chain pointer to null.
  void *pool = allocateRaw(MEM_POOL_SIZE);
  poolfirst_ = poolcur_ = (void **) pool;
  *poolfirst_ = 0;

  // Mark the rest free.
  freestart_ = (char *) pool + sizeof(void **);
  freeend_ = (char *) pool + MEM_POOL_SIZE;
}

IgProfBuffer::~IgProfBuffer

(

void

)

[protected]

Definition at line 29 of file IgProfBuffer.cc.

References MEM_POOL_SIZE, p, and poolfirst_.

{
  void **p = poolfirst_;
  while (p)
  {
    void **next = (void **) *p;
    munmap(p, MEM_POOL_SIZE);
    p = next;
  }
}

IgProfBuffer::IgProfBuffer

(

IgProfBuffer &

)

[private]

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Member Function Documentation

template<class T>

T* IgProfBuffer::allocate

(

void

)

[inline, protected]

Definition at line 29 of file IgProfBuffer.h.

References allocateSpace().

    { return static_cast<T *>(allocateSpace(sizeof(T))); }

void IgProfBuffer::allocatePool

(

void

)

[private]

Definition at line 62 of file IgProfBuffer.cc.

References allocateRaw(), freeend_, freestart_, MEM_POOL_SIZE, poolcur_, and poolfirst_.

Referenced by allocateSpace().

{
  // Get a pool.  If we don't have any pools yet, make this the first
  // one.  If we have an existing pool, chain the new one into the
  // last one.  Then make this the current and last pool and mark the
  // memory free.  Note the pool memory is allocated all-zeroes.
  void **pool = (void **) allocateRaw(MEM_POOL_SIZE);

  if (! poolfirst_)
    poolfirst_ = pool;

  if (poolcur_)
    *poolcur_ = pool;

  poolcur_ = pool;

  freestart_ = (char *) pool + sizeof(void **);
  freeend_ = (char *) pool + MEM_POOL_SIZE;
}

void * IgProfBuffer::allocateRaw

(

size_t

size

)

[protected]

Definition at line 47 of file IgProfBuffer.cc.

References data, IgProf::debug(), and mmap.

Referenced by allocatePool(), IgProfBuffer(), and IgProfTrace::IgProfTrace().

{
  void *data = mmap (0, size, PROT_READ | PROT_WRITE,
                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  if (data != MAP_FAILED)
    return data;
  else
  {
    IgProf::debug ("Failed to allocate memory for profile buffer: %s (%d)\n",
                   strerror (errno), errno);
    abort ();
  }
}

void* IgProfBuffer::allocateSpace

(

size_t

amount

)

[inline, protected]

Definition at line 19 of file IgProfBuffer.h.

References allocatePool(), freeend_, freestart_, and IGPROF_ASSERT.

Referenced by allocate(), and IgProfTrace::IgProfTrace().

    {
      if (size_t(freeend_ - freestart_) < amount)
        allocatePool();

      IGPROF_ASSERT(size_t(freeend_ - freestart_) > amount);
      void *p = freestart_;
      freestart_ += amount;
      return p;
    }

static uint32_t IgProfBuffer::hash

(

uintptr_t

key

)

[inline, static, protected]

Definition at line 32 of file IgProfBuffer.h.

References a, b, c, and rot.

Referenced by IgProfTrace::findResource(), IgProfSymCache::roundAddressToSymbol(), and IgProfSymCache::symbolForAddress().

    {
      // Reduced version of Bob Jenkins' hash function at:
      //   https://www.burtleburtle.net/bob/c/lookup3.c
      // Simply converted to operate on known sized fixed
      // integral keys and no initial value (initval = 0).
      //
      // in the end get the bin with 2^BITS mask:
      //   uint32_t bin = hash(key) & (((uint32_t)1 << BITS)-1);
#     define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
      uint32_t a, b, c;
      a = b = c = 0xdeadbeef + sizeof (key);
      b += key >> 32; // for 64-bit systems, may warn on 32-bit systems
      a += key & 0xffffffffU;
      c ^= b; c -= rot(b,14);
      a ^= c; a -= rot(c,11);
      b ^= a; b -= rot(a,25);
      c ^= b; c -= rot(b,16);
      a ^= c; a -= rot(c,4);
      b ^= a; b -= rot(a,14);
      c ^= b; c -= rot(b,24);
      return c;
#     undef rot
    }

IgProfBuffer& IgProfBuffer::operator=

(

IgProfBuffer &

)

[private]

void IgProfBuffer::unallocateRaw	(	void *	p,
		size_t	size
	)			[protected]

Definition at line 41 of file IgProfBuffer.cc.

Referenced by IgProfTrace::~IgProfTrace().

{
  munmap(p, size);
}

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Member Data Documentation

char* IgProfBuffer::freeend_ [private]

Definition at line 63 of file IgProfBuffer.h.

Referenced by allocatePool(), allocateSpace(), and IgProfBuffer().

char* IgProfBuffer::freestart_ [private]

Definition at line 62 of file IgProfBuffer.h.

Referenced by allocatePool(), allocateSpace(), and IgProfBuffer().

void** IgProfBuffer::poolcur_ [private]

Reimplemented in IgProfTrace.

Definition at line 61 of file IgProfBuffer.h.

Referenced by allocatePool(), and IgProfBuffer().

void** IgProfBuffer::poolfirst_ [private]

Reimplemented in IgProfTrace.

Definition at line 60 of file IgProfBuffer.h.

Referenced by allocatePool(), IgProfBuffer(), and ~IgProfBuffer().

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The documentation for this class was generated from the following files:

• IgTools/IgProf/src/IgProfBuffer.h
• IgTools/IgProf/src/IgProfBuffer.cc

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