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- /*
- * Copyright (c) 1983, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #include "gprof.h"
- #include "libiberty.h"
- #include "search_list.h"
- #include "source.h"
- #include "symtab.h"
- #include "cg_arcs.h"
- #include "cg_dfn.h"
- #include "utils.h"
- #define DFN_INCR_DEPTH (128)
- typedef struct
- {
- Sym *sym;
- int cycle_top;
- }
- DFN_Stack;
- static bool is_numbered (Sym *);
- static bool is_busy (Sym *);
- static void find_cycle (Sym *);
- static void pre_visit (Sym *);
- static void post_visit (Sym *);
- DFN_Stack *dfn_stack = NULL;
- int dfn_maxdepth = 0;
- int dfn_depth = 0;
- int dfn_counter = DFN_NAN;
- /*
- * Is CHILD already numbered?
- */
- static bool
- is_numbered (Sym *child)
- {
- return child->cg.top_order != DFN_NAN && child->cg.top_order != DFN_BUSY;
- }
- /*
- * Is CHILD already busy?
- */
- static bool
- is_busy (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
- find_cycle (Sym *child)
- {
- Sym *head = 0;
- Sym *tail;
- int cycle_top;
- int cycle_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 (cycle_index = cycle_top + 1; cycle_index <= dfn_depth; ++cycle_index)
- {
- child = dfn_stack[cycle_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
- pre_visit (Sym *parent)
- {
- ++dfn_depth;
- if (dfn_depth >= dfn_maxdepth)
- {
- dfn_maxdepth += DFN_INCR_DEPTH;
- dfn_stack = (DFN_Stack *) xrealloc (dfn_stack,
- dfn_maxdepth * sizeof *dfn_stack);
- }
- 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
- post_visit (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
- cg_dfn (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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