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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_numbered */
/*
* Is CHILD already busy?
*/
static bool
DEFUN(is_busy, (child), Sym *child)
{
if (child->cg.top_order == DFN_NAN) {
return FALSE;
} /* if */
return TRUE;
} /* is_busy */
/*
* 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 */
if (child->cg.cyc.head != child && child->cg.cyc.head == head) {
break;
} /* if */
} /* for */
if (cycle_top <= 0) {
fprintf(stderr, "[find_cycle] couldn't find head of cycle\n");
done(1);
} /* if */
DBG(DFNDEBUG, printf("[find_cycle] dfn_depth %d cycle_top %d ",
dfn_depth, cycle_top);
if (head) {
print_name(head);
} else {
printf("<unknown>");
} /* if */
printf("\n"));
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"));
} /* for */
/*
* 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"));
} /* if */
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"));
} /* for */
} else if (child->cg.cyc.head != head /* firewall */) {
fprintf(stderr, "[find_cycle] glommed, but not to head\n");
done(1);
} /* if */
} /* for */
} /* if */
} /* find_cycle */
/*
* 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);
} /* if */
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"));
} /* pre_visit */
/*
* 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));
} /* for */
} else {
DBG(DFNDEBUG, printf("[post_visit]\t\tis part of a cycle\n"));
} /* if */
--dfn_depth;
} /* post_visit */
/*
* 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 */
/*
* If we're already busy, must be a cycle:
*/
if (is_busy(parent)) {
find_cycle(parent);
return;
} /* if */
pre_visit(parent);
/*
* Recursively visit children:
*/
for (arc = parent->cg.children; arc; arc = arc->next_child) {
cg_dfn(arc->child);
} /* for */
post_visit(parent);
} /* cg_dfn */
/*** end of cg_dfn.c ***/
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