/*
** Copyright (C) 1997, 1999-2001 The University of Melbourne.
** This file may only be copied under the terms of the GNU Library General
** Public License - see the file COPYING.LIB in the Mercury distribution.
*/

/*
** File: mercury_heap_profile.c.
** Main authors: zs, fjh
**
** This module records information about the allocations of cells on the heap.
**
** The information recorded by this module is used by code in
** library/benchmarking.m.
*/

/*---------------------------------------------------------------------------*/

#include "mercury_imp.h"

#include <stdio.h>
#include <string.h>

#include "mercury_prof_mem.h"
#include "mercury_dword.h"
#include "mercury_heap_profile.h"

/* all fields of these variables are initialized to 0 */
MR_memprof_counter	MR_memprof_overall;
MR_memprof_table	MR_memprof_procs;
MR_memprof_table	MR_memprof_types;

/*
** Initialize a heap profiling counter.
*/
static void
MR_init_counter(MR_memprof_counter *counter)
{
	MR_zero_dword(counter->cells_at_period_start);
	MR_zero_dword(counter->words_at_period_start);
	MR_zero_dword(counter->cells_since_period_start);
	MR_zero_dword(counter->words_since_period_start);
}

/*
** Increment the fields in a heap profiling counter to record the allocation
** of a single cell of `size' words.
*/
static void
MR_increment_counter(MR_memprof_counter *counter, int size)
{
	MR_increment_dword(counter->cells_since_period_start, 1);
	MR_increment_dword(counter->words_since_period_start, size);
}

/*
** Search the specified `table' to find the entry for the given `name'
** allocating one if there isn't one already, and then increment
** the counters for that entry for an allocation of the specified `size'.
*/
static void
MR_increment_table_entry(MR_memprof_table *table, const char *name,
	MR_Code *addr, int size)
{
	MR_bool			found;
	int			diff;
	MR_memprof_record	**node_addr;
	MR_memprof_record	*node;

	/*
	** Search the tree to find the node with this name.
	*/
	found = MR_FALSE;
	node_addr = &table->root;
	while ((node = *node_addr) != NULL) {
		diff = strcmp(name, node->name);
		if (diff < 0) {
			node_addr = &node->left;
		} else if (diff > 0) {
			node_addr = &node->right;
		} else {
			found = MR_TRUE;
			break;
		}
	}

	/*
	** If the tree didn't already contain a node with this name,
	** create a new node for it.
	*/
	if (!found) {
		char *copy_of_name;

		node = MR_PROF_NEW(MR_memprof_record);
		/*
		** We need to make a fresh copy of the name,
		** rather than just copying the pointer, because
		** our caller may deallocate its copy of the name.
		** Normally the name will be a string literal,
		** but even then it might be a string literal from
		** a dlopen()'ed module which will later get dlclose()'d.
		*/
		copy_of_name = MR_PROF_NEW_ARRAY(char, strlen(name) + 1);
		strcpy(copy_of_name, name);
		node->name = copy_of_name;
		node->addr = addr;
		node->left = NULL;
		node->right = NULL;
		MR_init_counter(&node->counter);

		*node_addr = node;

		table->num_entries++;
	}

	/* Now record the counts in this node */
	MR_increment_counter(&node->counter, size);
}

/*
** Record heap profiling information for an allocation of size `size'
** in procedure `proc' for an object of type `type'.
*/
void
MR_record_allocation(int size, MR_Code *proc_addr,
	const char *proc_name, const char *type)
{
	/*
	** Increment the overall totals,
	** record the allocation in the per-procedure table, and
	** record the allocation in the per-type table.
	*/
	MR_increment_counter(&MR_memprof_overall, size);
	MR_increment_table_entry(&MR_memprof_procs, proc_name, proc_addr, size);
	MR_increment_table_entry(&MR_memprof_types, type, NULL, size);
}