304 lines
7.5 KiB
C
304 lines
7.5 KiB
C
/*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "gprof.h"
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#include "libiberty.h"
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#include "search_list.h"
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#include "source.h"
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#include "symtab.h"
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#include "cg_arcs.h"
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#include "cg_dfn.h"
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#include "utils.h"
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#define DFN_INCR_DEPTH (128)
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typedef struct
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{
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Sym *sym;
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int cycle_top;
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}
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DFN_Stack;
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static bfd_boolean is_numbered (Sym *);
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static bfd_boolean is_busy (Sym *);
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static void find_cycle (Sym *);
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static void pre_visit (Sym *);
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static void post_visit (Sym *);
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DFN_Stack *dfn_stack = NULL;
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int dfn_maxdepth = 0;
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int dfn_depth = 0;
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int dfn_counter = DFN_NAN;
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/*
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* Is CHILD already numbered?
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*/
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static bfd_boolean
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is_numbered (Sym *child)
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{
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return child->cg.top_order != DFN_NAN && child->cg.top_order != DFN_BUSY;
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}
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/*
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* Is CHILD already busy?
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*/
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static bfd_boolean
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is_busy (Sym *child)
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{
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if (child->cg.top_order == DFN_NAN)
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{
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return FALSE;
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}
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return TRUE;
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}
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/*
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* CHILD is part of a cycle. Find the top caller into this cycle
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* that is not part of the cycle and make all functions in cycle
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* members of that cycle (top caller == caller with smallest
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* depth-first number).
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*/
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static void
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find_cycle (Sym *child)
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{
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Sym *head = 0;
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Sym *tail;
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int cycle_top;
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int cycle_index;
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for (cycle_top = dfn_depth; cycle_top > 0; --cycle_top)
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{
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head = dfn_stack[cycle_top].sym;
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if (child == head)
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{
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break;
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}
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if (child->cg.cyc.head != child && child->cg.cyc.head == head)
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{
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break;
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}
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}
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if (cycle_top <= 0)
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{
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fprintf (stderr, "[find_cycle] couldn't find head of cycle\n");
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done (1);
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}
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#ifdef DEBUG
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if (debug_level & DFNDEBUG)
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{
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printf ("[find_cycle] dfn_depth %d cycle_top %d ",
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dfn_depth, cycle_top);
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if (head)
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{
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print_name (head);
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}
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else
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{
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printf ("<unknown>");
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}
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printf ("\n");
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}
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#endif
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if (cycle_top == dfn_depth)
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{
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/*
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* This is previous function, e.g. this calls itself. Sort of
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* boring.
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*
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* Since we are taking out self-cycles elsewhere no need for
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* the special case, here.
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*/
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DBG (DFNDEBUG,
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printf ("[find_cycle] ");
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print_name (child);
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printf ("\n"));
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}
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else
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{
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/*
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* Glom intervening functions that aren't already glommed into
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* this cycle. Things have been glommed when their cyclehead
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* field points to the head of the cycle they are glommed
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* into.
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*/
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for (tail = head; tail->cg.cyc.next; tail = tail->cg.cyc.next)
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{
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/* void: chase down to tail of things already glommed */
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DBG (DFNDEBUG,
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printf ("[find_cycle] tail ");
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print_name (tail);
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printf ("\n"));
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}
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/*
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* If what we think is the top of the cycle has a cyclehead
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* field, then it's not really the head of the cycle, which is
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* really what we want.
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*/
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if (head->cg.cyc.head != head)
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{
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head = head->cg.cyc.head;
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DBG (DFNDEBUG, printf ("[find_cycle] new cyclehead ");
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print_name (head);
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printf ("\n"));
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}
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for (cycle_index = cycle_top + 1; cycle_index <= dfn_depth; ++cycle_index)
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{
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child = dfn_stack[cycle_index].sym;
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if (child->cg.cyc.head == child)
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{
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/*
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* Not yet glommed anywhere, glom it and fix any
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* children it has glommed.
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*/
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tail->cg.cyc.next = child;
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child->cg.cyc.head = head;
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DBG (DFNDEBUG, printf ("[find_cycle] glomming ");
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print_name (child);
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printf (" onto ");
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print_name (head);
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printf ("\n"));
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for (tail = child; tail->cg.cyc.next; tail = tail->cg.cyc.next)
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{
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tail->cg.cyc.next->cg.cyc.head = head;
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DBG (DFNDEBUG, printf ("[find_cycle] and its tail ");
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print_name (tail->cg.cyc.next);
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printf (" onto ");
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print_name (head);
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printf ("\n"));
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}
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}
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else if (child->cg.cyc.head != head /* firewall */ )
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{
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fprintf (stderr, "[find_cycle] glommed, but not to head\n");
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done (1);
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}
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}
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}
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}
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/*
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* Prepare for visiting the children of PARENT. Push a parent onto
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* the stack and mark it busy.
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*/
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static void
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pre_visit (Sym *parent)
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{
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++dfn_depth;
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if (dfn_depth >= dfn_maxdepth)
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{
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dfn_maxdepth += DFN_INCR_DEPTH;
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dfn_stack = (DFN_Stack *) xrealloc (dfn_stack,
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dfn_maxdepth * sizeof *dfn_stack);
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}
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dfn_stack[dfn_depth].sym = parent;
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dfn_stack[dfn_depth].cycle_top = dfn_depth;
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parent->cg.top_order = DFN_BUSY;
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DBG (DFNDEBUG, printf ("[pre_visit]\t\t%d:", dfn_depth);
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print_name (parent);
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printf ("\n"));
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}
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/*
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* Done with visiting node PARENT. Pop PARENT off dfn_stack
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* and number functions if PARENT is head of a cycle.
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*/
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static void
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post_visit (Sym *parent)
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{
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Sym *member;
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DBG (DFNDEBUG, printf ("[post_visit]\t%d: ", dfn_depth);
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print_name (parent);
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printf ("\n"));
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/*
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* Number functions and things in their cycles unless the function
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* is itself part of a cycle:
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*/
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if (parent->cg.cyc.head == parent)
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{
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++dfn_counter;
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for (member = parent; member; member = member->cg.cyc.next)
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{
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member->cg.top_order = dfn_counter;
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DBG (DFNDEBUG, printf ("[post_visit]\t\tmember ");
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print_name (member);
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printf ("-> cg.top_order = %d\n", dfn_counter));
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}
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}
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else
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{
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DBG (DFNDEBUG, printf ("[post_visit]\t\tis part of a cycle\n"));
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}
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--dfn_depth;
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}
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/*
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* Given this PARENT, depth first number its children.
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*/
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void
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cg_dfn (Sym *parent)
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{
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Arc *arc;
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DBG (DFNDEBUG, printf ("[dfn] dfn( ");
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print_name (parent);
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printf (")\n"));
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/*
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* If we're already numbered, no need to look any further:
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*/
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if (is_numbered (parent))
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{
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return;
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}
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/*
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* If we're already busy, must be a cycle:
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*/
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if (is_busy (parent))
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{
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find_cycle (parent);
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return;
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}
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pre_visit (parent);
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/*
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* Recursively visit children:
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*/
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for (arc = parent->cg.children; arc; arc = arc->next_child)
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{
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cg_dfn (arc->child);
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}
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post_visit (parent);
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}
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