source: kBuild/trunk/src/kmk/make.c@ 45

/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
#if 0
static char sccsid[] = "@(#)make.c      8.1 (Berkeley) 6/6/93";
#else
static const char rcsid[] =
  "$FreeBSD: src/usr.bin/make/make.c,v 1.11 1999/09/11 13:08:01 hoek Exp $";
#endif
#endif /* not lint */

/*-
 * make.c --
 *      The functions which perform the examination of targets and
 *      their suitability for creation
 *
 * Interface:
 *      Make_Run                Initialize things for the module and recreate
 *                              whatever needs recreating. Returns TRUE if
 *                              work was (or would have been) done and FALSE
 *                              otherwise.
 *
 *      Make_Update             Update all parents of a given child. Performs
 *                              various bookkeeping chores like the updating
 *                              of the cmtime field of the parent, filling
 *                              of the IMPSRC context variable, etc. It will
 *                              place the parent on the toBeMade queue if it
 *                              should be.
 *
 *      Make_TimeStamp          Function to set the parent's cmtime field
 *                              based on a child's modification time.
 *
 *      Make_DoAllVar           Set up the various local variables for a
 *                              target, including the .ALLSRC variable, making
 *                              sure that any variable that needs to exist
 *                              at the very least has the empty value.
 *
 *      Make_OODate             Determine if a target is out-of-date.
 *
 *      Make_HandleUse          See if a child is a .USE node for a parent
 *                              and perform the .USE actions if so.
 */

#include    "make.h"
#include    "hash.h"
#include    "dir.h"
#include    "job.h"

static Lst      toBeMade;       /* The current fringe of the graph. These
                                 * are nodes which await examination by
                                 * MakeOODate. It is added to by
                                 * Make_Update and subtracted from by
                                 * MakeStartJobs */
static int      numNodes;       /* Number of nodes to be processed. If this
                                 * is non-zero when Job_Empty() returns
                                 * TRUE, there's a cycle in the graph */

static int MakeAddChild __P((ClientData, ClientData));
static int MakeAddAllSrc __P((ClientData, ClientData));
static int MakeTimeStamp __P((ClientData, ClientData));
static int MakeHandleUse __P((ClientData, ClientData));
static Boolean MakeStartJobs __P((void));
static int MakePrintStatus __P((ClientData, ClientData));
/*-
 *-----------------------------------------------------------------------
 * Make_TimeStamp --
 *      Set the cmtime field of a parent node based on the mtime stamp in its
 *      child. Called from MakeOODate via Lst_ForEach.
 *
 * Results:
 *      Always returns 0.
 *
 * Side Effects:
 *      The cmtime of the parent node will be changed if the mtime
 *      field of the child is greater than it.
 *-----------------------------------------------------------------------
 */
int
Make_TimeStamp (pgn, cgn)
    GNode *pgn; /* the current parent */
    GNode *cgn; /* the child we've just examined */
{
    if (cgn->mtime > pgn->cmtime) {
        pgn->cmtime = cgn->mtime;
    }
    return (0);
}

static int
MakeTimeStamp (pgn, cgn)
    ClientData pgn;     /* the current parent */
    ClientData cgn;     /* the child we've just examined */
{
    return Make_TimeStamp((GNode *) pgn, (GNode *) cgn);
}


/*-
 *-----------------------------------------------------------------------
 * Make_OODate --
 *      See if a given node is out of date with respect to its sources.
 *      Used by Make_Run when deciding which nodes to place on the
 *      toBeMade queue initially and by Make_Update to screen out USE and
 *      EXEC nodes. In the latter case, however, any other sort of node
 *      must be considered out-of-date since at least one of its children
 *      will have been recreated.
 *
 * Results:
 *      TRUE if the node is out of date. FALSE otherwise.
 *
 * Side Effects:
 *      The mtime field of the node and the cmtime field of its parents
 *      will/may be changed.
 *-----------------------------------------------------------------------
 */
Boolean
Make_OODate (gn)
    register GNode *gn;       /* the node to check */
{
    Boolean         oodate;

    /*
     * Certain types of targets needn't even be sought as their datedness
     * doesn't depend on their modification time...
     */
    if ((gn->type & (OP_JOIN|OP_USE|OP_EXEC)) == 0) {
        (void) Dir_MTime (gn);
        if (DEBUG(MAKE)) {
            if (gn->mtime != 0) {
                printf ("modified %s...", Targ_FmtTime(gn->mtime));
            } else {
                printf ("non-existent...");
            }
        }
    }

    /*
     * A target is remade in one of the following circumstances:
     *  its modification time is smaller than that of its youngest child
     *      and it would actually be run (has commands or type OP_NOP)
     *  it's the object of a force operator
     *  it has no children, was on the lhs of an operator and doesn't exist
     *      already.
     *
     * Libraries are only considered out-of-date if the archive module says
     * they are.
     *
     * These weird rules are brought to you by Backward-Compatability and
     * the strange people who wrote 'Make'.
     */
    if (gn->type & OP_USE) {
        /*
         * If the node is a USE node it is *never* out of date
         * no matter *what*.
         */
        if (DEBUG(MAKE)) {
            printf(".USE node...");
        }
        oodate = FALSE;
    } else if (gn->type & OP_LIB) {
        if (DEBUG(MAKE)) {
            printf("library...");
        }

        /*
         * always out of date if no children and :: target
         */

        oodate = Arch_LibOODate (gn) ||
            ((gn->cmtime == 0) && (gn->type & OP_DOUBLEDEP));
    } else if (gn->type & OP_JOIN) {
        /*
         * A target with the .JOIN attribute is only considered
         * out-of-date if any of its children was out-of-date.
         */
        if (DEBUG(MAKE)) {
            printf(".JOIN node...");
        }
        oodate = gn->childMade;
    } else if (gn->type & (OP_FORCE|OP_EXEC|OP_PHONY)) {
        /*
         * A node which is the object of the force (!) operator or which has
         * the .EXEC attribute is always considered out-of-date.
         */
        if (DEBUG(MAKE)) {
            if (gn->type & OP_FORCE) {
                printf("! operator...");
            } else if (gn->type & OP_PHONY) {
                printf(".PHONY node...");
            } else {
                printf(".EXEC node...");
            }
        }
        oodate = TRUE;
    } else if ((gn->mtime < gn->cmtime) ||
               ((gn->cmtime == 0) &&
                ((gn->mtime==0) || (gn->type & OP_DOUBLEDEP))))
    {
        /*
         * A node whose modification time is less than that of its
         * youngest child or that has no children (cmtime == 0) and
         * either doesn't exist (mtime == 0) or was the object of a
         * :: operator is out-of-date. Why? Because that's the way Make does
         * it.
         */
        if (DEBUG(MAKE)) {
            if (gn->mtime < gn->cmtime) {
                printf("modified before source...");
            } else if (gn->mtime == 0) {
                printf("non-existent and no sources...");
            } else {
                printf(":: operator and no sources...");
            }
        }
        oodate = TRUE;
    } else {
#if 0
        /* WHY? */
        if (DEBUG(MAKE)) {
            printf("source %smade...", gn->childMade ? "" : "not ");
        }
        oodate = gn->childMade;
#else
        oodate = FALSE;
#endif /* 0 */
    }

    /*
     * If the target isn't out-of-date, the parents need to know its
     * modification time. Note that targets that appear to be out-of-date
     * but aren't, because they have no commands and aren't of type OP_NOP,
     * have their mtime stay below their children's mtime to keep parents from
     * thinking they're out-of-date.
     */
    if (!oodate) {
        Lst_ForEach (gn->parents, MakeTimeStamp, (ClientData)gn);
    }

    return (oodate);
}


/*-
 *-----------------------------------------------------------------------
 * MakeAddChild  --
 *      Function used by Make_Run to add a child to the list l.
 *      It will only add the child if its make field is FALSE.
 *
 * Results:
 *      Always returns 0
 *
 * Side Effects:
 *      The given list is extended
 *-----------------------------------------------------------------------
 */
static int
MakeAddChild (gnp, lp)
    ClientData     gnp;         /* the node to add */
    ClientData     lp;          /* the list to which to add it */
{
    GNode          *gn = (GNode *) gnp;
    Lst            l = (Lst) lp;

    if (!gn->make && !(gn->type & OP_USE)) {
        (void)Lst_EnQueue (l, (ClientData)gn);
    }
    return (0);
}


/*-
 *-----------------------------------------------------------------------
 * Make_HandleUse --
 *      Function called by Make_Run and SuffApplyTransform on the downward
 *      pass to handle .USE and transformation nodes. A callback function
 *      for Lst_ForEach, it implements the .USE and transformation
 *      functionality by copying the node's commands, type flags
 *      and children to the parent node. Should be called before the
 *      children are enqueued to be looked at by MakeAddChild.
 *
 *      A .USE node is much like an explicit transformation rule, except
 *      its commands are always added to the target node, even if the
 *      target already has commands.
 *
 * Results:
 *      returns 0.
 *
 * Side Effects:
 *      Children and commands may be added to the parent and the parent's
 *      type may be changed.
 *
 *-----------------------------------------------------------------------
 */
int
Make_HandleUse (cgn, pgn)
    register GNode      *cgn;   /* The .USE node */
    register GNode      *pgn;   /* The target of the .USE node */
{
    register GNode      *gn;    /* A child of the .USE node */
    register LstNode    ln;     /* An element in the children list */

    if (cgn->type & (OP_USE|OP_TRANSFORM)) {
        if ((cgn->type & OP_USE) || Lst_IsEmpty(pgn->commands)) {
            /*
             * .USE or transformation and target has no commands -- append
             * the child's commands to the parent.
             */
            (void) Lst_Concat (pgn->commands, cgn->commands, LST_CONCNEW);
        }

        if (Lst_Open (cgn->children) == SUCCESS) {
            while ((ln = Lst_Next (cgn->children)) != NILLNODE) {
                gn = (GNode *)Lst_Datum (ln);

                if (Lst_Member (pgn->children, gn) == NILLNODE) {
                    (void) Lst_AtEnd (pgn->children, gn);
                    (void) Lst_AtEnd (gn->parents, pgn);
                    pgn->unmade += 1;
                }
            }
            Lst_Close (cgn->children);
        }

        pgn->type |= cgn->type & ~(OP_OPMASK|OP_USE|OP_TRANSFORM);

        /*
         * This child node is now "made", so we decrement the count of
         * unmade children in the parent... We also remove the child
         * from the parent's list to accurately reflect the number of decent
         * children the parent has. This is used by Make_Run to decide
         * whether to queue the parent or examine its children...
         */
        if (cgn->type & OP_USE) {
            pgn->unmade--;
        }
    }
    return (0);
}
static int
MakeHandleUse (pgn, cgn)
    ClientData pgn;     /* the current parent */
    ClientData cgn;     /* the child we've just examined */
{
    return Make_HandleUse((GNode *) pgn, (GNode *) cgn);
}


/*-
 *-----------------------------------------------------------------------
 * Make_Update  --
 *      Perform update on the parents of a node. Used by JobFinish once
 *      a node has been dealt with and by MakeStartJobs if it finds an
 *      up-to-date node.
 *
 * Results:
 *      Always returns 0
 *
 * Side Effects:
 *      The unmade field of pgn is decremented and pgn may be placed on
 *      the toBeMade queue if this field becomes 0.
 *
 *      If the child was made, the parent's childMade field will be set true
 *      and its cmtime set to now.
 *
 *      If the child wasn't made, the cmtime field of the parent will be
 *      altered if the child's mtime is big enough.
 *
 *      Finally, if the child is the implied source for the parent, the
 *      parent's IMPSRC variable is set appropriately.
 *
 *-----------------------------------------------------------------------
 */
void
Make_Update (cgn)
    register GNode *cgn;        /* the child node */
{
    register GNode      *pgn;   /* the parent node */
    register char       *cname; /* the child's name */
    register LstNode    ln;     /* Element in parents and iParents lists */
    char *p1;

    cname = Var_Value (TARGET, cgn, &p1);
    efree(p1);

    /*
     * If the child was actually made, see what its modification time is
     * now -- some rules won't actually update the file. If the file still
     * doesn't exist, make its mtime now.
     */
    if (cgn->made != UPTODATE) {
#ifndef RECHECK
        /*
         * We can't re-stat the thing, but we can at least take care of rules
         * where a target depends on a source that actually creates the
         * target, but only if it has changed, e.g.
         *
         * parse.h : parse.o
         *
         * parse.o : parse.y
         *      yacc -d parse.y
         *      cc -c y.tab.c
         *      mv y.tab.o parse.o
         *      cmp -s y.tab.h parse.h || mv y.tab.h parse.h
         *
         * In this case, if the definitions produced by yacc haven't changed
         * from before, parse.h won't have been updated and cgn->mtime will
         * reflect the current modification time for parse.h. This is
         * something of a kludge, I admit, but it's a useful one..
         * XXX: People like to use a rule like
         *
         * FRC:
         *
         * To force things that depend on FRC to be made, so we have to
         * check for gn->children being empty as well...
         */
        if (!Lst_IsEmpty(cgn->commands) || Lst_IsEmpty(cgn->children)) {
            cgn->mtime = now;
        }
#else
        /*
         * This is what Make does and it's actually a good thing, as it
         * allows rules like
         *
         *      cmp -s y.tab.h parse.h || cp y.tab.h parse.h
         *
         * to function as intended. Unfortunately, thanks to the stateless
         * nature of NFS (by which I mean the loose coupling of two clients
         * using the same file from a common server), there are times
         * when the modification time of a file created on a remote
         * machine will not be modified before the local stat() implied by
         * the Dir_MTime occurs, thus leading us to believe that the file
         * is unchanged, wreaking havoc with files that depend on this one.
         *
         * I have decided it is better to make too much than to make too
         * little, so this stuff is commented out unless you're sure it's ok.
         * -- ardeb 1/12/88
         */
        /*
         * Christos, 4/9/92: If we are  saving commands pretend that
         * the target is made now. Otherwise archives with ... rules
         * don't work!
         */
        if (noExecute || (cgn->type & OP_SAVE_CMDS) || Dir_MTime(cgn) == 0) {
            cgn->mtime = now;
        }
        if (DEBUG(MAKE)) {
            printf("update time: %s\n", Targ_FmtTime(cgn->mtime));
        }
#endif
    }

    if (Lst_Open (cgn->parents) == SUCCESS) {
        while ((ln = Lst_Next (cgn->parents)) != NILLNODE) {
            pgn = (GNode *)Lst_Datum (ln);
            if (pgn->make) {
                pgn->unmade -= 1;

                if ( ! (cgn->type & (OP_EXEC|OP_USE))) {
                    if (cgn->made == MADE) {
                        pgn->childMade = TRUE;
                        if (pgn->cmtime < cgn->mtime) {
                            pgn->cmtime = cgn->mtime;
                        }
                    } else {
                        (void)Make_TimeStamp (pgn, cgn);
                    }
                }
                if (pgn->unmade == 0) {
                    /*
                     * Queue the node up -- any unmade predecessors will
                     * be dealt with in MakeStartJobs.
                     */
                    (void)Lst_EnQueue (toBeMade, (ClientData)pgn);
                } else if (pgn->unmade < 0) {
                    Error ("Graph cycles through %s", pgn->name);
                }
            }
        }
        Lst_Close (cgn->parents);
    }
    /*
     * Deal with successor nodes. If any is marked for making and has an unmade
     * count of 0, has not been made and isn't in the examination queue,
     * it means we need to place it in the queue as it restrained itself
     * before.
     */
    for (ln = Lst_First(cgn->successors); ln != NILLNODE; ln = Lst_Succ(ln)) {
        GNode   *succ = (GNode *)Lst_Datum(ln);

        if (succ->make && succ->unmade == 0 && succ->made == UNMADE &&
            Lst_Member(toBeMade, (ClientData)succ) == NILLNODE)
        {
            (void)Lst_EnQueue(toBeMade, (ClientData)succ);
        }
    }

    /*
     * Set the .PREFIX and .IMPSRC variables for all the implied parents
     * of this node.
     */
    if (Lst_Open (cgn->iParents) == SUCCESS) {
        char    *p1;
        char    *cpref = Var_Value(PREFIX, cgn, &p1);

        while ((ln = Lst_Next (cgn->iParents)) != NILLNODE) {
            pgn = (GNode *)Lst_Datum (ln);
            if (pgn->make) {
                Var_Set (IMPSRC, cname, pgn);
                Var_Set (PREFIX, cpref, pgn);
            }
        }
        efree(p1);
        Lst_Close (cgn->iParents);
    }
}


/*-
 *-----------------------------------------------------------------------
 * MakeAddAllSrc --
 *      Add a child's name to the ALLSRC and OODATE variables of the given
 *      node. Called from Make_DoAllVar via Lst_ForEach. A child is added only
 *      if it has not been given the .EXEC, .USE or .INVISIBLE attributes.
 *      .EXEC and .USE children are very rarely going to be files, so...
 *      A child is added to the OODATE variable if its modification time is
 *      later than that of its parent, as defined by Make, except if the
 *      parent is a .JOIN node. In that case, it is only added to the OODATE
 *      variable if it was actually made (since .JOIN nodes don't have
 *      modification times, the comparison is rather unfair...)..
 *
 * Results:
 *      Always returns 0
 *
 * Side Effects:
 *      The ALLSRC variable for the given node is extended.
 *-----------------------------------------------------------------------
 */
static int
MakeAddAllSrc (cgnp, pgnp)
    ClientData  cgnp;   /* The child to add */
    ClientData  pgnp;   /* The parent to whose ALLSRC variable it should be */
                        /* added */
{
    GNode       *cgn = (GNode *) cgnp;
    GNode       *pgn = (GNode *) pgnp;
    if ((cgn->type & (OP_EXEC|OP_USE|OP_INVISIBLE)) == 0) {
        char *child;
        char *p1 = NULL;

        if (OP_NOP(cgn->type)) {
            /*
             * this node is only source; use the specific pathname for it
             */
            child = cgn->path ? cgn->path : cgn->name;
        }
        else
            child = Var_Value(TARGET, cgn, &p1);
        Var_Append (ALLSRC, child, pgn);
        if (pgn->type & OP_JOIN) {
            if (cgn->made == MADE) {
                Var_Append(OODATE, child, pgn);
            }
        } else if ((pgn->mtime < cgn->mtime) ||
                   (cgn->mtime >= now && cgn->made == MADE))
        {
            /*
             * It goes in the OODATE variable if the parent is younger than the
             * child or if the child has been modified more recently than
             * the start of the make. This is to keep pmake from getting
             * confused if something else updates the parent after the
             * make starts (shouldn't happen, I know, but sometimes it
             * does). In such a case, if we've updated the kid, the parent
             * is likely to have a modification time later than that of
             * the kid and anything that relies on the OODATE variable will
             * be hosed.
             *
             * XXX: This will cause all made children to go in the OODATE
             * variable, even if they're not touched, if RECHECK isn't defined,
             * since cgn->mtime is set to now in Make_Update. According to
             * some people, this is good...
             */
            Var_Append(OODATE, child, pgn);
        }
        efree(p1);
    }
    return (0);
}


#ifdef KMK
/*-
 *-----------------------------------------------------------------------
 * MakeAddAllSrc --
 *
 * Results:
 *      Always returns 0
 *
 * Side Effects:
 *      The PARENTS variable for the given node is extended.
 *-----------------------------------------------------------------------
 */
static int
MakeAddParents (cgnp, pgnp)
    ClientData  pgnp;   /* The parent to add to add */
    ClientData  cgnp;   /* The child to whose PARENTS variable it should be */
{
    GNode       *pgn = (GNode *) pgnp;
    GNode       *cgn = (GNode *) cgnp;
    if ((pgn->type & (OP_EXEC|OP_USE|OP_INVISIBLE)) == 0) {
        char *parent;
        char *p1 = NULL;

        if (OP_NOP(pgn->type)) {
            /*
             * this node is only source; use the specific pathname for it
             */
            parent = pgn->path ? pgn->path : pgn->name;
        }
        else
            parent = Var_Value(TARGET, pgn, &p1);
        Var_Append(PARENTS, parent, cgn);
        efree(p1);
    }
    return (0);
}
#endif


/*-
 *-----------------------------------------------------------------------
 * Make_DoAllVar --
 *      Set up the ALLSRC and OODATE variables. Sad to say, it must be
 *      done separately, rather than while traversing the graph. This is
 *      because Make defined OODATE to contain all sources whose modification
 *      times were later than that of the target, *not* those sources that
 *      were out-of-date. Since in both compatibility and native modes,
 *      the modification time of the parent isn't found until the child
 *      has been dealt with, we have to wait until now to fill in the
 *      variable. As for ALLSRC, the ordering is important and not
 *      guaranteed when in native mode, so it must be set here, too.
 *
 * Results:
 *      None
 *
 * Side Effects:
 *      The ALLSRC and OODATE variables of the given node is filled in.
 *      If the node is a .JOIN node, its TARGET variable will be set to
 *      match its ALLSRC variable.
 *-----------------------------------------------------------------------
 */
void
Make_DoAllVar (gn)
    GNode       *gn;
{
    Lst_ForEach (gn->children, MakeAddAllSrc, (ClientData) gn);
    #ifdef KMK
    Lst_ForEach (gn->parents, MakeAddParents, (ClientData) gn);
    #endif

    if (!Var_Exists (OODATE, gn)) {
        Var_Set (OODATE, "", gn);
    }
    if (!Var_Exists (ALLSRC, gn)) {
        Var_Set (ALLSRC, "", gn);
    }

    if (gn->type & OP_JOIN) {
        char *p1;
        Var_Set (TARGET, Var_Value (ALLSRC, gn, &p1), gn);
        efree(p1);
    }
}


/*-
 *-----------------------------------------------------------------------
 * MakeStartJobs --
 *      Start as many jobs as possible.
 *
 * Results:
 *      If the query flag was given to pmake, no job will be started,
 *      but as soon as an out-of-date target is found, this function
 *      returns TRUE. At all other times, this function returns FALSE.
 *
 * Side Effects:
 *      Nodes are removed from the toBeMade queue and job table slots
 *      are filled.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
MakeStartJobs ()
{
    register GNode      *gn;

    while (!Job_Full() && !Lst_IsEmpty (toBeMade)) {
        gn = (GNode *) Lst_DeQueue (toBeMade);
        if (DEBUG(MAKE)) {
            printf ("Examining %s...", gn->name);
        }
        /*
         * Make sure any and all predecessors that are going to be made,
         * have been.
         */
        if (!Lst_IsEmpty(gn->preds)) {
            LstNode ln;

            for (ln = Lst_First(gn->preds); ln != NILLNODE; ln = Lst_Succ(ln)){
                GNode   *pgn = (GNode *)Lst_Datum(ln);

                if (pgn->make && pgn->made == UNMADE) {
                    if (DEBUG(MAKE)) {
                        printf("predecessor %s not made yet.\n", pgn->name);
                    }
                    break;
                }
            }
            /*
             * If ln isn't nil, there's a predecessor as yet unmade, so we
             * just drop this node on the floor. When the node in question
             * has been made, it will notice this node as being ready to
             * make but as yet unmade and will place the node on the queue.
             */
            if (ln != NILLNODE) {
                continue;
            }
        }

        numNodes--;
        if (Make_OODate (gn)) {
            if (DEBUG(MAKE)) {
                printf ("out-of-date\n");
            }
            if (queryFlag) {
                return (TRUE);
            }
            Make_DoAllVar (gn);
            Job_Make (gn);
        } else {
            if (DEBUG(MAKE)) {
                printf ("up-to-date\n");
            }
            gn->made = UPTODATE;
            if (gn->type & OP_JOIN) {
                /*
                 * Even for an up-to-date .JOIN node, we need it to have its
                 * context variables so references to it get the correct
                 * value for .TARGET when building up the context variables
                 * of its parent(s)...
                 */
                Make_DoAllVar (gn);
            }

            Make_Update (gn);
        }
    }
    return (FALSE);
}


/*-
 *-----------------------------------------------------------------------
 * MakePrintStatus --
 *      Print the status of a top-level node, viz. it being up-to-date
 *      already or not created due to an error in a lower level.
 *      Callback function for Make_Run via Lst_ForEach.
 *
 * Results:
 *      Always returns 0.
 *
 * Side Effects:
 *      A message may be printed.
 *
 *-----------------------------------------------------------------------
 */
static int
MakePrintStatus(gnp, cyclep)
    ClientData  gnp;        /* Node to examine */
    ClientData  cyclep;     /* True if gn->unmade being non-zero implies
                             * a cycle in the graph, not an error in an
                             * inferior */
{
    GNode       *gn = (GNode *) gnp;
    Boolean     cycle = *(Boolean *) cyclep;
    if (gn->made == UPTODATE) {
        printf ("`%s' is up to date.\n", gn->name);
    } else if (gn->unmade != 0) {
        if (cycle) {
            Boolean t = TRUE;
            /*
             * If printing cycles and came to one that has unmade children,
             * print out the cycle by recursing on its children. Note a
             * cycle like:
             *  a : b
             *  b : c
             *  c : b
             * will cause this to erroneously complain about a being in
             * the cycle, but this is a good approximation.
             */
            if (gn->made == CYCLE) {
                Error("Graph cycles through `%s'", gn->name);
                gn->made = ENDCYCLE;
                Lst_ForEach(gn->children, MakePrintStatus, (ClientData) &t);
                gn->made = UNMADE;
            } else if (gn->made != ENDCYCLE) {
                gn->made = CYCLE;
                Lst_ForEach(gn->children, MakePrintStatus, (ClientData) &t);
            }
        } else {
            printf ("`%s' not remade because of errors.\n", gn->name);
        }
    }
    return (0);
}


/*-
 *-----------------------------------------------------------------------
 * Make_Run --
 *      Initialize the nodes to remake and the list of nodes which are
 *      ready to be made by doing a breadth-first traversal of the graph
 *      starting from the nodes in the given list. Once this traversal
 *      is finished, all the 'leaves' of the graph are in the toBeMade
 *      queue.
 *      Using this queue and the Job module, work back up the graph,
 *      calling on MakeStartJobs to keep the job table as full as
 *      possible.
 *
 * Results:
 *      TRUE if work was done. FALSE otherwise.
 *
 * Side Effects:
 *      The make field of all nodes involved in the creation of the given
 *      targets is set to 1. The toBeMade list is set to contain all the
 *      'leaves' of these subgraphs.
 *-----------------------------------------------------------------------
 */
Boolean
Make_Run (targs)
    Lst             targs;      /* the initial list of targets */
{
    register GNode  *gn;        /* a temporary pointer */
    register Lst    examine;    /* List of targets to examine */
    int             errors;     /* Number of errors the Job module reports */

    toBeMade = Lst_Init (FALSE);

    examine = Lst_Duplicate(targs, NOCOPY);
    numNodes = 0;

    /*
     * Make an initial downward pass over the graph, marking nodes to be made
     * as we go down. We call Suff_FindDeps to find where a node is and
     * to get some children for it if it has none and also has no commands.
     * If the node is a leaf, we stick it on the toBeMade queue to
     * be looked at in a minute, otherwise we add its children to our queue
     * and go on about our business.
     */
    while (!Lst_IsEmpty (examine)) {
        gn = (GNode *) Lst_DeQueue (examine);

        if (!gn->make) {
            gn->make = TRUE;
            numNodes++;

            /*
             * Apply any .USE rules before looking for implicit dependencies
             * to make sure everything has commands that should...
             */
            Lst_ForEach (gn->children, MakeHandleUse, (ClientData)gn);
            Suff_FindDeps (gn);

            if (gn->unmade != 0) {
                Lst_ForEach (gn->children, MakeAddChild, (ClientData)examine);
            } else {
                (void)Lst_EnQueue (toBeMade, (ClientData)gn);
            }
        }
    }

    Lst_Destroy (examine, NOFREE);

    if (queryFlag) {
        /*
         * We wouldn't do any work unless we could start some jobs in the
         * next loop... (we won't actually start any, of course, this is just
         * to see if any of the targets was out of date)
         */
        return (MakeStartJobs());
    } else {
        /*
         * Initialization. At the moment, no jobs are running and until some
         * get started, nothing will happen since the remaining upward
         * traversal of the graph is performed by the routines in job.c upon
         * the finishing of a job. So we fill the Job table as much as we can
         * before going into our loop.
         */
        (void) MakeStartJobs();
    }

    /*
     * Main Loop: The idea here is that the ending of jobs will take
     * care of the maintenance of data structures and the waiting for output
     * will cause us to be idle most of the time while our children run as
     * much as possible. Because the job table is kept as full as possible,
     * the only time when it will be empty is when all the jobs which need
     * running have been run, so that is the end condition of this loop.
     * Note that the Job module will exit if there were any errors unless the
     * keepgoing flag was given.
     */
    while (!Job_Empty ()) {
        Job_CatchOutput ();
        Job_CatchChildren (!usePipes);
        (void)MakeStartJobs();
    }

    errors = Job_End();

    /*
     * Print the final status of each target. E.g. if it wasn't made
     * because some inferior reported an error.
     */
    errors = ((errors == 0) && (numNodes != 0));
    Lst_ForEach(targs, MakePrintStatus, (ClientData) &errors);

    return (TRUE);
}