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/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <stdio.h>
#include "gprof.h"
#include "cg_arcs.h"
#include "cg_dfn.h"
#include "symtab.h"
#include "utils.h"
#define DFN_DEPTH 100
typedef struct
{
Sym *sym;
int cycle_top;
}
DFN_Stack;
DFN_Stack dfn_stack[DFN_DEPTH];
int dfn_depth = 0;
int dfn_counter = DFN_NAN;
/*
* Is CHILD already numbered?
*/
static bool
DEFUN (is_numbered, (child), Sym * child)
{
return child->cg.top_order != DFN_NAN && child->cg.top_order != DFN_BUSY;
}
/*
* Is CHILD already busy?
*/
static bool
DEFUN (is_busy, (child), Sym * child)
{
if (child->cg.top_order == DFN_NAN)
{
return FALSE;
}
return TRUE;
}
/*
* CHILD is part of a cycle. Find the top caller into this cycle
* that is not part of the cycle and make all functions in cycle
* members of that cycle (top caller == caller with smallest
* depth-first number).
*/
static void
DEFUN (find_cycle, (child), Sym * child)
{
Sym *head = 0;
Sym *tail;
int cycle_top;
int index;
for (cycle_top = dfn_depth; cycle_top > 0; --cycle_top)
{
head = dfn_stack[cycle_top].sym;
if (child == head)
{
break;
}
if (child->cg.cyc.head != child && child->cg.cyc.head == head)
{
break;
}
}
if (cycle_top <= 0)
{
fprintf (stderr, "[find_cycle] couldn't find head of cycle\n");
done (1);
}
#ifdef DEBUG
if (debug_level & DFNDEBUG)
{
printf ("[find_cycle] dfn_depth %d cycle_top %d ",
dfn_depth, cycle_top);
if (head)
{
print_name (head);
}
else
{
printf ("<unknown>");
}
printf ("\n");
}
#endif
if (cycle_top == dfn_depth)
{
/*
* This is previous function, e.g. this calls itself. Sort of
* boring.
*
* Since we are taking out self-cycles elsewhere no need for
* the special case, here.
*/
DBG (DFNDEBUG,
printf ("[find_cycle] ");
print_name (child);
printf ("\n"));
}
else
{
/*
* Glom intervening functions that aren't already glommed into
* this cycle. Things have been glommed when their cyclehead
* field points to the head of the cycle they are glommed
* into.
*/
for (tail = head; tail->cg.cyc.next; tail = tail->cg.cyc.next)
{
/* void: chase down to tail of things already glommed */
DBG (DFNDEBUG,
printf ("[find_cycle] tail ");
print_name (tail);
printf ("\n"));
}
/*
* If what we think is the top of the cycle has a cyclehead
* field, then it's not really the head of the cycle, which is
* really what we want.
*/
if (head->cg.cyc.head != head)
{
head = head->cg.cyc.head;
DBG (DFNDEBUG, printf ("[find_cycle] new cyclehead ");
print_name (head);
printf ("\n"));
}
for (index = cycle_top + 1; index <= dfn_depth; ++index)
{
child = dfn_stack[index].sym;
if (child->cg.cyc.head == child)
{
/*
* Not yet glommed anywhere, glom it and fix any
* children it has glommed.
*/
tail->cg.cyc.next = child;
child->cg.cyc.head = head;
DBG (DFNDEBUG, printf ("[find_cycle] glomming ");
print_name (child);
printf (" onto ");
print_name (head);
printf ("\n"));
for (tail = child; tail->cg.cyc.next; tail = tail->cg.cyc.next)
{
tail->cg.cyc.next->cg.cyc.head = head;
DBG (DFNDEBUG, printf ("[find_cycle] and its tail ");
print_name (tail->cg.cyc.next);
printf (" onto ");
print_name (head);
printf ("\n"));
}
}
else if (child->cg.cyc.head != head /* firewall */ )
{
fprintf (stderr, "[find_cycle] glommed, but not to head\n");
done (1);
}
}
}
}
/*
* Prepare for visiting the children of PARENT. Push a parent onto
* the stack and mark it busy.
*/
static void
DEFUN (pre_visit, (parent), Sym * parent)
{
++dfn_depth;
if (dfn_depth >= DFN_DEPTH)
{
fprintf (stderr, "[pre_visit] dfn_stack overflow\n");
done (1);
}
dfn_stack[dfn_depth].sym = parent;
dfn_stack[dfn_depth].cycle_top = dfn_depth;
parent->cg.top_order = DFN_BUSY;
DBG (DFNDEBUG, printf ("[pre_visit]\t\t%d:", dfn_depth);
print_name (parent);
printf ("\n"));
}
/*
* Done with visiting node PARENT. Pop PARENT off dfn_stack
* and number functions if PARENT is head of a cycle.
*/
static void
DEFUN (post_visit, (parent), Sym * parent)
{
Sym *member;
DBG (DFNDEBUG, printf ("[post_visit]\t%d: ", dfn_depth);
print_name (parent);
printf ("\n"));
/*
* Number functions and things in their cycles unless the function
* is itself part of a cycle:
*/
if (parent->cg.cyc.head == parent)
{
++dfn_counter;
for (member = parent; member; member = member->cg.cyc.next)
{
member->cg.top_order = dfn_counter;
DBG (DFNDEBUG, printf ("[post_visit]\t\tmember ");
print_name (member);
printf ("-> cg.top_order = %d\n", dfn_counter));
}
}
else
{
DBG (DFNDEBUG, printf ("[post_visit]\t\tis part of a cycle\n"));
}
--dfn_depth;
}
/*
* Given this PARENT, depth first number its children.
*/
void
DEFUN (cg_dfn, (parent), Sym * parent)
{
Arc *arc;
DBG (DFNDEBUG, printf ("[dfn] dfn( ");
print_name (parent);
printf (")\n"));
/*
* If we're already numbered, no need to look any further:
*/
if (is_numbered (parent))
{
return;
}
/*
* If we're already busy, must be a cycle:
*/
if (is_busy (parent))
{
find_cycle (parent);
return;
}
pre_visit (parent);
/*
* Recursively visit children:
*/
for (arc = parent->cg.children; arc; arc = arc->next_child)
{
cg_dfn (arc->child);
}
post_visit (parent);
}
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