/*      $NetBSD: make.c,v 1.272 2025/05/18 07:02:00 rillig Exp $        */

/*
* Copyright (c) 1988, 1989, 1990, 1993
*      The Regents of the University of California.  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. 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.
*/

/*
* 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.
*/

/*
* Examination of targets and their suitability for creation.
*
* Interface:
*      Make_MakeParallel
*                      Make the targets in parallel mode.
*
*      Make_Update     After a target is made, update all its parents.
*                      Perform various bookkeeping chores like the updating
*                      of the youngestChild field of the parent, filling
*                      of the IMPSRC variable, etc. Place the parent on the
*                      toBeMade queue if it should be.
*
*      GNode_UpdateYoungestChild
*                      Update the node's youngestChild field based on the
*                      child's modification time.
*
*      GNode_SetLocalVars
*                      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.
*
*      GNode_IsOODate  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.
*
*      Make_ExpandUse  Expand .USE nodes
*/

#include "make.h"
#include "dir.h"
#include "job.h"
#ifdef USE_META
# include "meta.h"
#endif

/*      "@(#)make.c     8.1 (Berkeley) 6/6/93"  */
MAKE_RCSID("$NetBSD: make.c,v 1.272 2025/05/18 07:02:00 rillig Exp $");

/* Sequence # to detect recursion. */
static unsigned checked_seqno = 1;

/*
* 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 GNodeList toBeMade = LST_INIT;


void
debug_printf(const char *fmt, ...)
{
       va_list ap;

       va_start(ap, fmt);
       vfprintf(opts.debug_file, fmt, ap);
       va_end(ap);
}

char *
GNodeType_ToString(GNodeType type)
{
       Buffer buf;

       Buf_Init(&buf);
#define ADD(flag) Buf_AddFlag(&buf, (type & (flag)) != OP_NONE, #flag)
       ADD(OP_DEPENDS);
       ADD(OP_FORCE);
       ADD(OP_DOUBLEDEP);
       ADD(OP_OPTIONAL);
       ADD(OP_USE);
       ADD(OP_EXEC);
       ADD(OP_IGNORE);
       ADD(OP_PRECIOUS);
       ADD(OP_SILENT);
       ADD(OP_MAKE);
       ADD(OP_JOIN);
       ADD(OP_MADE);
       ADD(OP_SPECIAL);
       ADD(OP_USEBEFORE);
       ADD(OP_INVISIBLE);
       ADD(OP_NOTMAIN);
       ADD(OP_PHONY);
       ADD(OP_NOPATH);
       ADD(OP_WAIT);
       ADD(OP_NOMETA);
       ADD(OP_META);
       ADD(OP_NOMETA_CMP);
       ADD(OP_SUBMAKE);
       ADD(OP_TRANSFORM);
       ADD(OP_MEMBER);
       ADD(OP_LIB);
       ADD(OP_ARCHV);
       ADD(OP_HAS_COMMANDS);
       ADD(OP_SAVE_CMDS);
       ADD(OP_DEPS_FOUND);
       ADD(OP_MARK);
#undef ADD
       if (buf.len == 0)
               Buf_AddStr(&buf, "none");
       return Buf_DoneData(&buf);
}

static char *
GNodeFlags_ToString(GNodeFlags flags)
{
       Buffer buf;

       Buf_Init(&buf);
       Buf_AddFlag(&buf, flags.remake, "REMAKE");
       Buf_AddFlag(&buf, flags.childMade, "CHILDMADE");
       Buf_AddFlag(&buf, flags.force, "FORCE");
       Buf_AddFlag(&buf, flags.doneWait, "DONE_WAIT");
       Buf_AddFlag(&buf, flags.doneOrder, "DONE_ORDER");
       Buf_AddFlag(&buf, flags.fromDepend, "FROM_DEPEND");
       Buf_AddFlag(&buf, flags.doneAllsrc, "DONE_ALLSRC");
       Buf_AddFlag(&buf, flags.cycle, "CYCLE");
       Buf_AddFlag(&buf, flags.doneCycle, "DONECYCLE");
       if (buf.len == 0)
               Buf_AddStr(&buf, "none");
       return Buf_DoneData(&buf);
}

void
GNode_FprintDetails(FILE *f, const char *prefix, const GNode *gn,
                   const char *suffix)
{
       char *type = GNodeType_ToString(gn->type);
       char *flags = GNodeFlags_ToString(gn->flags);

       fprintf(f, "%s%s, type %s, flags %s%s",
           prefix, GNodeMade_Name(gn->made), type, flags, suffix);
       free(type);
       free(flags);
}

bool
GNode_ShouldExecute(GNode *gn)
{
       return !((gn->type & OP_MAKE)
           ? opts.noRecursiveExecute
           : opts.noExecute);
}

/* Update the youngest child of the node, according to the given child. */
void
GNode_UpdateYoungestChild(GNode *gn, GNode *cgn)
{
       if (gn->youngestChild == NULL || cgn->mtime > gn->youngestChild->mtime)
               gn->youngestChild = cgn;
}

static bool
IsOODateRegular(GNode *gn)
{
       /* These rules are inherited from the original Make. */

       if (gn->youngestChild != NULL) {
               if (gn->mtime < gn->youngestChild->mtime) {
                       DEBUG1(MAKE, "modified before source \"%s\"...",
                           GNode_Path(gn->youngestChild));
                       return true;
               }
               return false;
       }

       if (gn->mtime == 0 && !(gn->type & OP_OPTIONAL)) {
               DEBUG0(MAKE, "nonexistent and no sources...");
               return true;
       }

       if (gn->type & OP_DOUBLEDEP) {
               DEBUG0(MAKE, ":: operator and no sources...");
               return true;
       }

       return false;
}

/*
* See if the node is out of date with respect to its sources.
*
* Used by Make_MakeParallel 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.
*
* The mtime field of the node and the youngestChild field of its parents
* may be changed.
*/
bool
GNode_IsOODate(GNode *gn)
{
       bool 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_USEBEFORE | OP_EXEC))) {
               Dir_UpdateMTime(gn, true);
               if (DEBUG(MAKE)) {
                       if (gn->mtime != 0)
                               debug_printf("modified %s...",
                                   Targ_FmtTime(gn->mtime));
                       else
                               debug_printf("nonexistent...");
               }
       }

       /*
        * 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 is not
        *      GNode_IsTarget)
        *
        *      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-Compatibility
        * and the strange people who wrote 'Make'.
        */
       if (gn->type & (OP_USE | OP_USEBEFORE)) {
               /*
                * If the node is a USE node it is *never* out of date
                * no matter *what*.
                */
               DEBUG0(MAKE, ".USE node...");
               oodate = false;
       } else if ((gn->type & OP_LIB) && (gn->mtime == 0 || Arch_IsLib(gn))) {
               DEBUG0(MAKE, "library...");

               /*
                * always out of date if no children and :: target
                * or nonexistent.
                */
               oodate = (gn->mtime == 0 || Arch_LibOODate(gn) ||
                         (gn->youngestChild == NULL &&
                          (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.
                */
               DEBUG0(MAKE, ".JOIN node...");
               DEBUG1(MAKE, "source %smade...",
                   gn->flags.childMade ? "" : "not ");
               oodate = gn->flags.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)
                               debug_printf("! operator...");
                       else if (gn->type & OP_PHONY)
                               debug_printf(".PHONY node...");
                       else
                               debug_printf(".EXEC node...");
               }
               oodate = true;
       } else if (IsOODateRegular(gn)) {
               oodate = true;
       } else {
               /*
                * When a nonexistent child with no sources
                * (such as a typically used FORCE source) has been made and
                * the target of the child (usually a directory) has the same
                * timestamp as the timestamp just given to the nonexistent
                * child after it was considered made.
                */
               if (DEBUG(MAKE)) {
                       if (gn->flags.force)
                               debug_printf("non existing child...");
               }
               oodate = gn->flags.force;
       }

#ifdef USE_META
       if (useMeta)
               oodate = meta_oodate(gn, oodate);
#endif

       /*
        * 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 are GNode_IsTarget,
        * have their mtime stay below their children's mtime to keep parents
        * from thinking they're out-of-date.
        */
       if (!oodate) {
               GNodeListNode *ln;
               for (ln = gn->parents.first; ln != NULL; ln = ln->next)
                       GNode_UpdateYoungestChild(ln->datum, gn);
       }

       return oodate;
}

static void
PretendAllChildrenAreMade(GNode *pgn)
{
       GNodeListNode *ln;

       for (ln = pgn->children.first; ln != NULL; ln = ln->next) {
               GNode *cgn = ln->datum;

               /* This may also update cgn->path. */
               Dir_UpdateMTime(cgn, false);
               GNode_UpdateYoungestChild(pgn, cgn);
               pgn->unmade--;
       }
}

/*
* Called by Make_MakeParallel and SuffApplyTransform on the downward pass to
* handle .USE and transformation nodes, by copying the child node's commands,
* type flags and children to the parent node.
*
* 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.
*
* Input:
*      cgn             The source node, which is either a .USE/.USEBEFORE
*                      node or a transformation node (OP_TRANSFORM).
*      pgn             The target node
*/
void
Make_HandleUse(GNode *cgn, GNode *pgn)
{
       GNodeListNode *ln;      /* An element in the children list */

#ifdef DEBUG_SRC
       if (!(cgn->type & (OP_USE | OP_USEBEFORE | OP_TRANSFORM))) {
               debug_printf("Make_HandleUse: called for plain node %s\n",
                   cgn->name);
               /* XXX: debug mode should not affect control flow */
               return;
       }
#endif

       if ((cgn->type & (OP_USE | OP_USEBEFORE)) ||
           Lst_IsEmpty(&pgn->commands)) {
               if (cgn->type & OP_USEBEFORE) {
                       /* .USEBEFORE */
                       Lst_PrependAll(&pgn->commands, &cgn->commands);
               } else {
                       /* .USE, or target has no commands */
                       Lst_AppendAll(&pgn->commands, &cgn->commands);
               }
       }

       for (ln = cgn->children.first; ln != NULL; ln = ln->next) {
               GNode *gn = ln->datum;

               /*
                * Expand variables in the .USE node's name
                * and save the unexpanded form.
                * We don't need to do this for commands.
                * They get expanded properly when we execute.
                */
               if (gn->uname == NULL)
                       gn->uname = gn->name;
               else
                       free(gn->name);
               gn->name = Var_Subst(gn->uname, pgn, VARE_EVAL);
               /* TODO: handle errors */
               if (gn->uname != NULL && strcmp(gn->name, gn->uname) != 0) {
                       /* See if we have a target for this node. */
                       GNode *tgn = Targ_FindNode(gn->name);
                       if (tgn != NULL)
                               gn = tgn;
               }

               Lst_Append(&pgn->children, gn);
               Lst_Append(&gn->parents, pgn);
               pgn->unmade++;
       }

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

/*
* Used by Make_MakeParallel on the downward pass to handle .USE nodes. Should
* be called before the children are enqueued to be looked at by MakeAddChild.
*
* For a .USE child, the commands, type flags and children are copied to the
* parent node, and since the relation to the .USE node is then no longer
* needed, that relation is removed.
*
* Input:
*      cgn             the child, which may be a .USE node
*      pgn             the current parent
*/
static void
MakeHandleUse(GNode *cgn, GNode *pgn, GNodeListNode *ln)
{
       bool unmarked;

       unmarked = !(cgn->type & OP_MARK);
       cgn->type |= OP_MARK;

       if (!(cgn->type & (OP_USE | OP_USEBEFORE)))
               return;

       if (unmarked)
               Make_HandleUse(cgn, pgn);

       Lst_Remove(&pgn->children, ln);
       pgn->unmade--;
}

static void
HandleUseNodes(GNode *gn)
{
       GNodeListNode *ln, *nln;
       for (ln = gn->children.first; ln != NULL; ln = nln) {
               nln = ln->next;
               MakeHandleUse(ln->datum, gn, ln);
       }
}


/*
* Check the modification time of a gnode, and update it if necessary.
* Return 0 if the gnode does not exist, or its filesystem time if it does.
*/
time_t
Make_Recheck(GNode *gn)
{
       time_t mtime;

       Dir_UpdateMTime(gn, true);
       mtime = gn->mtime;

#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 gn->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(gn->commands) || Lst_IsEmpty(gn->children))
               gn->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_UpdateMTime 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 (!GNode_ShouldExecute(gn) || (gn->type & OP_SAVE_CMDS) ||
           (mtime == 0 && !(gn->type & OP_WAIT))) {
               DEBUG2(MAKE, " recheck(%s): update time from %s to now\n",
                   gn->name,
                   gn->mtime == 0 ? "nonexistent" : Targ_FmtTime(gn->mtime));
               gn->mtime = now;
       } else {
               DEBUG2(MAKE, " recheck(%s): current update time: %s\n",
                   gn->name, Targ_FmtTime(gn->mtime));
       }
#endif

       /*
        * XXX: The returned mtime may differ from gn->mtime. Intentionally?
        */
       return mtime;
}

/*
* Set the .PREFIX and .IMPSRC variables for all the implied parents
* of this node.
*/
static void
UpdateImplicitParentsVars(GNode *cgn, const char *cname)
{
       GNodeListNode *ln;
       const char *cpref = GNode_VarPrefix(cgn);

       for (ln = cgn->implicitParents.first; ln != NULL; ln = ln->next) {
               GNode *pgn = ln->datum;
               if (pgn->flags.remake) {
                       Var_Set(pgn, IMPSRC, cname);
                       if (cpref != NULL)
                               Var_Set(pgn, PREFIX, cpref);
               }
       }
}

/* See if a .ORDER rule stops us from building this node. */
static bool
IsWaitingForOrder(GNode *gn)
{
       GNodeListNode *ln;

       for (ln = gn->order_pred.first; ln != NULL; ln = ln->next) {
               GNode *ogn = ln->datum;

               if (GNode_IsDone(ogn) || !ogn->flags.remake)
                       continue;

               DEBUG2(MAKE,
                   "IsWaitingForOrder: Waiting for .ORDER node \"%s%s\"\n",
                   ogn->name, ogn->cohort_num);
               return true;
       }
       return false;
}

static bool MakeBuildChild(GNode *, GNodeListNode *);

static void
ScheduleOrderSuccessors(GNode *gn)
{
       GNodeListNode *toBeMadeNext = toBeMade.first;
       GNodeListNode *ln;

       for (ln = gn->order_succ.first; ln != NULL; ln = ln->next) {
               GNode *succ = ln->datum;

               if (succ->made == DEFERRED &&
                   !MakeBuildChild(succ, toBeMadeNext))
                       succ->flags.doneOrder = true;
       }
}

/*
* 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.
*
* 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 flag CHILDMADE field will be
* set true.
*
* If the child is not up-to-date and still does not exist,
* set the FORCE flag on the parents.
*
* If the child wasn't made, the youngestChild 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(GNode *cgn)
{
       const char *cname;      /* the child's name */
       time_t mtime = -1;
       GNodeList *parents;
       GNodeListNode *ln;
       GNode *centurion;

       /* It is save to re-examine any nodes again */
       checked_seqno++;

       cname = GNode_VarTarget(cgn);

       DEBUG2(MAKE, "Make_Update: %s%s\n", cgn->name, cgn->cohort_num);

       /*
        * 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)
               mtime = Make_Recheck(cgn);

       /*
        * If this is a `::' node, we must consult its first instance
        * which is where all parents are linked.
        */
       if ((centurion = cgn->centurion) != NULL) {
               if (!Lst_IsEmpty(&cgn->parents))
                       Punt("%s%s: cohort has parents", cgn->name,
                           cgn->cohort_num);
               centurion->unmade_cohorts--;
               if (centurion->unmade_cohorts < 0)
                       Error("Graph cycles through centurion %s",
                           centurion->name);
       } else {
               centurion = cgn;
       }
       parents = &centurion->parents;

       /* If this was a .ORDER node, schedule the RHS */
       ScheduleOrderSuccessors(centurion);

       /* Now mark all the parents as having one less unmade child */
       for (ln = parents->first; ln != NULL; ln = ln->next) {
               GNode *pgn = ln->datum;

               if (DEBUG(MAKE)) {
                       debug_printf("inspect parent %s%s: ", pgn->name,
                           pgn->cohort_num);
                       GNode_FprintDetails(opts.debug_file, "", pgn, "");
                       debug_printf(", unmade %d ", pgn->unmade - 1);
               }

               if (!pgn->flags.remake) {
                       /* This parent isn't needed */
                       DEBUG0(MAKE, "- not needed\n");
                       continue;
               }
               if (mtime == 0 && !(cgn->type & OP_WAIT))
                       pgn->flags.force = true;

               /*
                * If the parent has the .MADE attribute, its timestamp got
                * updated to that of its newest child, and its unmade
                * child count got set to zero in Make_ExpandUse().
                * However other things might cause us to build one of its
                * children - and so we mustn't do any processing here when
                * the child build finishes.
                */
               if (pgn->type & OP_MADE) {
                       DEBUG0(MAKE, "- .MADE\n");
                       continue;
               }

               if (!(cgn->type & (OP_EXEC | OP_USE | OP_USEBEFORE))) {
                       if (cgn->made == MADE)
                               pgn->flags.childMade = true;
                       GNode_UpdateYoungestChild(pgn, cgn);
               }

               /*
                * A parent must wait for the completion of all instances
                * of a `::' dependency.
                */
               if (centurion->unmade_cohorts != 0 ||
                   !GNode_IsDone(centurion)) {
                       DEBUG2(MAKE,
                           "- centurion made %d, %d unmade cohorts\n",
                           centurion->made, centurion->unmade_cohorts);
                       continue;
               }

               /* One more child of this parent is now made */
               pgn->unmade--;
               if (pgn->unmade < 0) {
                       if (DEBUG(MAKE)) {
                               debug_printf("Graph cycles through %s%s\n",
                                   pgn->name, pgn->cohort_num);
                               Targ_PrintGraph(2);
                       }
                       Error("Graph cycles through %s%s", pgn->name,
                           pgn->cohort_num);
               }

               /*
                * We must always rescan the parents of .WAIT and .ORDER
                * nodes.
                */
               if (pgn->unmade != 0 && !(centurion->type & OP_WAIT)
                   && !centurion->flags.doneOrder) {
                       DEBUG0(MAKE, "- unmade children\n");
                       continue;
               }
               if (pgn->made != DEFERRED) {
                       /*
                        * Either this parent is on a different branch of
                        * the tree, or it on the RHS of a .WAIT directive
                        * or it is already on the toBeMade list.
                        */
                       DEBUG0(MAKE, "- not deferred\n");
                       continue;
               }

               if (IsWaitingForOrder(pgn))
                       continue;

               if (DEBUG(MAKE)) {
                       debug_printf("- %s%s made, schedule %s%s (made %d)\n",
                           cgn->name, cgn->cohort_num,
                           pgn->name, pgn->cohort_num, pgn->made);
                       Targ_PrintNode(pgn, 2);
               }
               /* Ok, we can schedule the parent again */
               pgn->made = REQUESTED;
               Lst_Enqueue(&toBeMade, pgn);
       }

       UpdateImplicitParentsVars(cgn, cname);
}

static void
UnmarkChildren(GNode *gn)
{
       GNodeListNode *ln;

       for (ln = gn->children.first; ln != NULL; ln = ln->next) {
               GNode *child = ln->datum;
               child->type &= (unsigned)~OP_MARK;
       }
}

/*
* Add a child's name to the ALLSRC and OODATE variables of the given
* node, but 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...
*
* If the child is a .JOIN node, its ALLSRC is propagated to the parent.
*
* 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...)..
*
* Input:
*      cgn             The child to add
*      pgn             The parent to whose ALLSRC variable it should
*                      be added
*/
static void
MakeAddAllSrc(GNode *cgn, GNode *pgn)
{
       const char *child, *allsrc;

       if (cgn->type & OP_MARK)
               return;
       cgn->type |= OP_MARK;

       if (cgn->type & (OP_EXEC | OP_USE | OP_USEBEFORE | OP_INVISIBLE))
               return;

       if (cgn->type & OP_ARCHV)
               child = GNode_VarMember(cgn);
       else
               child = GNode_Path(cgn);

       if (cgn->type & OP_JOIN)
               allsrc = GNode_VarAllsrc(cgn);
       else
               allsrc = child;

       if (allsrc != NULL)
               Var_Append(pgn, ALLSRC, allsrc);

       if (pgn->type & OP_JOIN) {
               if (cgn->made == MADE)
                       Var_Append(pgn, OODATE, child);

       } 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 child,
                * the parent is likely to have a modification time
                * later than that of the child 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(pgn, OODATE, child);
       }
}

/*
* 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.
*
* If the node is a .JOIN node, its TARGET variable will be set to
* match its ALLSRC variable.
*/
void
GNode_SetLocalVars(GNode *gn)
{
       GNodeListNode *ln;

       if (gn->flags.doneAllsrc)
               return;

       UnmarkChildren(gn);
       for (ln = gn->children.first; ln != NULL; ln = ln->next)
               MakeAddAllSrc(ln->datum, gn);

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

       if (gn->type & OP_JOIN)
               Var_Set(gn, TARGET, GNode_VarAllsrc(gn));
       gn->flags.doneAllsrc = true;
}

static void
ScheduleRandomly(GNode *gn)
{
       GNodeListNode *ln;
       size_t i, n;

       n = 0;
       for (ln = toBeMade.first; ln != NULL; ln = ln->next)
               n++;
       i = n > 0 ? (size_t)random() % (n + 1) : 0;

       if (i == 0) {
               Lst_Append(&toBeMade, gn);
               return;
       }
       i--;

       for (ln = toBeMade.first; i > 0; ln = ln->next)
               i--;
       Lst_InsertBefore(&toBeMade, ln, gn);
}

static bool
MakeBuildChild(GNode *cn, GNodeListNode *toBeMadeNext)
{

       if (DEBUG(MAKE)) {
               debug_printf("MakeBuildChild: inspect %s%s, ",
                   cn->name, cn->cohort_num);
               GNode_FprintDetails(opts.debug_file, "", cn, "\n");
       }
       if (GNode_IsReady(cn))
               return false;

       /* If this node is on the RHS of a .ORDER, check LHSs. */
       if (IsWaitingForOrder(cn)) {
               /*
                * Can't build this (or anything else in this child list) yet
                */
               cn->made = DEFERRED;
               return false;   /* but keep looking */
       }

       DEBUG2(MAKE, "MakeBuildChild: schedule %s%s\n",
           cn->name, cn->cohort_num);

       cn->made = REQUESTED;
       if (opts.randomizeTargets && !(cn->type & OP_WAIT))
               ScheduleRandomly(cn);
       else if (toBeMadeNext == NULL)
               Lst_Append(&toBeMade, cn);
       else
               Lst_InsertBefore(&toBeMade, toBeMadeNext, cn);

       if (cn->unmade_cohorts != 0) {
               ListNode *ln;

               for (ln = cn->cohorts.first; ln != NULL; ln = ln->next)
                       if (MakeBuildChild(ln->datum, toBeMadeNext))
                               break;
       }

       /*
        * If this node is a .WAIT node with unmade children
        * then don't add the next sibling.
        */
       return cn->type & OP_WAIT && cn->unmade > 0;
}

static void
MakeChildren(GNode *gn)
{
       GNodeListNode *toBeMadeNext = toBeMade.first;
       GNodeListNode *ln;

       for (ln = gn->children.first; ln != NULL; ln = ln->next)
               if (MakeBuildChild(ln->datum, toBeMadeNext))
                       break;
}

/*
* Start as many jobs as possible, taking them from the toBeMade queue.
*
* If the -q option was given, no job will be started,
* but as soon as an out-of-date target is found, this function
* returns true. In all other cases, this function returns false.
*/
static bool
MakeStartJobs(void)
{
       GNode *gn;
       bool have_token = false;

       while (!Lst_IsEmpty(&toBeMade)) {
               /*
                * Get token now to avoid cycling job-list when we only
                * have 1 token
                */
               if (!have_token && !TokenPool_Take())
                       break;
               have_token = true;

               gn = Lst_Dequeue(&toBeMade);
               DEBUG2(MAKE, "Examining %s%s...\n", gn->name, gn->cohort_num);

               if (gn->made != REQUESTED) {
                       debug_printf("internal error: made = %s\n",
                           GNodeMade_Name(gn->made));
                       Targ_PrintNode(gn, 2);
                       Targ_PrintNodes(&toBeMade, 2);
                       Targ_PrintGraph(3);
                       abort();
               }

               if (gn->checked_seqno == checked_seqno) {
                       /*
                        * We've already looked at this node since a job
                        * finished...
                        */
                       DEBUG2(MAKE, "already checked %s%s\n",
                           gn->name, gn->cohort_num);
                       gn->made = DEFERRED;
                       continue;
               }
               gn->checked_seqno = checked_seqno;

               if (gn->unmade != 0) {
                       gn->made = DEFERRED;
                       MakeChildren(gn);
                       DEBUG2(MAKE, "deferred %s%s\n",
                           gn->name, gn->cohort_num);
                       continue;
               }

               gn->made = BEINGMADE;
               if (GNode_IsOODate(gn)) {
                       DEBUG0(MAKE, "out-of-date\n");
                       if (opts.query)
                               return strcmp(gn->name, ".MAIN") != 0;
                       GNode_SetLocalVars(gn);
                       Job_Make(gn);
                       have_token = false;
               } else {
                       DEBUG0(MAKE, "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 local variables so
                                * references to it get the correct value
                                * for .TARGET when building up the local
                                * variables of its parent(s)...
                                */
                               GNode_SetLocalVars(gn);
                       }
                       Make_Update(gn);
               }
       }

       if (have_token)
               TokenPool_Return();

       return false;
}

/* Print the status of a .ORDER node. */
static void
MakePrintStatusOrderNode(GNode *ogn, GNode *gn)
{
       if (!GNode_IsWaitingFor(ogn))
               return;

       printf("    `%s%s' has .ORDER dependency on %s%s ",
           gn->name, gn->cohort_num, ogn->name, ogn->cohort_num);
       GNode_FprintDetails(stdout, "(", ogn, ")\n");

       if (DEBUG(MAKE) && opts.debug_file != stdout) {
               debug_printf("    `%s%s' has .ORDER dependency on %s%s ",
                   gn->name, gn->cohort_num, ogn->name, ogn->cohort_num);
               GNode_FprintDetails(opts.debug_file, "(", ogn, ")\n");
       }
}

static void
MakePrintStatusOrder(GNode *gn)
{
       GNodeListNode *ln;
       for (ln = gn->order_pred.first; ln != NULL; ln = ln->next)
               MakePrintStatusOrderNode(ln->datum, gn);
}

static void MakePrintStatusList(GNodeList *, int *);

/*
* 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.
*/
static bool
MakePrintStatus(GNode *gn, int *errors)
{
       if (gn->flags.doneCycle) {
               /*
                * We've completely processed this node before, don't do
                * it again.
                */
               return false;
       }

       if (gn->unmade == 0) {
               gn->flags.doneCycle = true;
               switch (gn->made) {
               case UPTODATE:
                       printf("`%s%s' is up to date.\n", gn->name,
                           gn->cohort_num);
                       break;
               case MADE:
                       break;
               case UNMADE:
               case DEFERRED:
               case REQUESTED:
               case BEINGMADE:
                       (*errors)++;
                       printf("`%s%s' was not built", gn->name,
                           gn->cohort_num);
                       GNode_FprintDetails(stdout, " (", gn, ")!\n");
                       if (DEBUG(MAKE) && opts.debug_file != stdout) {
                               debug_printf("`%s%s' was not built", gn->name,
                                   gn->cohort_num);
                               GNode_FprintDetails(opts.debug_file, " (", gn,
                                   ")!\n");
                       }
                       /* Most likely problem is actually caused by .ORDER */
                       MakePrintStatusOrder(gn);
                       break;
               default:
                       /* Errors - already counted */
                       printf("`%s%s' not remade because of errors.\n",
                           gn->name, gn->cohort_num);
                       if (DEBUG(MAKE) && opts.debug_file != stdout)
                               debug_printf(
                                   "`%s%s' not remade because of errors.\n",
                                   gn->name, gn->cohort_num);
                       break;
               }
               return false;
       }

       DEBUG3(MAKE, "MakePrintStatus: %s%s has %d unmade children\n",
           gn->name, gn->cohort_num, gn->unmade);
       /*
        * If printing cycles and came to one that has unmade children,
        * print out the cycle by recursing on its children.
        */
       if (!gn->flags.cycle) {
               /* First time we've seen this node, check all children */
               gn->flags.cycle = true;
               MakePrintStatusList(&gn->children, errors);
               /* Mark that this node needn't be processed again */
               gn->flags.doneCycle = true;
               return false;
       }

       /* Only output the error once per node */
       gn->flags.doneCycle = true;
       Error("Graph cycles through `%s%s'", gn->name, gn->cohort_num);
       if ((*errors)++ > 100)
               /* Abandon the whole error report */
               return true;

       /* Reporting for our children will give the rest of the loop */
       MakePrintStatusList(&gn->children, errors);
       return false;
}

static void
MakePrintStatusList(GNodeList *gnodes, int *errors)
{
       GNodeListNode *ln;

       for (ln = gnodes->first; ln != NULL; ln = ln->next)
               if (MakePrintStatus(ln->datum, errors))
                       break;
}

static void
ExamineLater(GNodeList *examine, GNodeList *toBeExamined)
{
       GNodeListNode *ln;

       for (ln = toBeExamined->first; ln != NULL; ln = ln->next) {
               GNode *gn = ln->datum;

               if (gn->flags.remake)
                       continue;
               if (gn->type & (OP_USE | OP_USEBEFORE))
                       continue;

               DEBUG2(MAKE, "ExamineLater: need to examine \"%s%s\"\n",
                   gn->name, gn->cohort_num);
               Lst_Enqueue(examine, gn);
       }
}

/* Expand .USE nodes and create a new targets list. */
void
Make_ExpandUse(GNodeList *targets)
{
       GNodeList examine = LST_INIT;   /* Queue of targets to examine */
       Lst_AppendAll(&examine, targets);

       /*
        * 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.
        */
       while (!Lst_IsEmpty(&examine)) {
               GNode *gn = Lst_Dequeue(&examine);

               if (gn->flags.remake)
                       continue;
               gn->flags.remake = true;

               DEBUG2(MAKE, "Make_ExpandUse: examine %s%s\n",
                   gn->name, gn->cohort_num);

               if (gn->type & OP_DOUBLEDEP)
                       Lst_PrependAll(&examine, &gn->cohorts);

               /*
                * Apply any .USE rules before looking for implicit
                * dependencies to make sure everything has commands that
                * should.
                *
                * Make sure that the TARGET is set, so that we can make
                * expansions.
                */
               if (gn->type & OP_ARCHV) {
                       char *eoa = strchr(gn->name, '(');
                       char *eon = strchr(gn->name, ')');
                       if (eoa == NULL || eon == NULL)
                               continue;
                       *eoa = '\0';
                       *eon = '\0';
                       Var_Set(gn, MEMBER, eoa + 1);
                       Var_Set(gn, ARCHIVE, gn->name);
                       *eoa = '(';
                       *eon = ')';
               }

               Dir_UpdateMTime(gn, false);
               Var_Set(gn, TARGET, GNode_Path(gn));
               UnmarkChildren(gn);
               HandleUseNodes(gn);

               if (!(gn->type & OP_MADE))
                       Suff_FindDeps(gn);
               else {
                       PretendAllChildrenAreMade(gn);
                       if (gn->unmade != 0) {
                               printf(
                                   "Warning: "
                                   "%s%s still has %d unmade children\n",
                                   gn->name, gn->cohort_num, gn->unmade);
                       }
               }

               if (gn->unmade != 0)
                       ExamineLater(&examine, &gn->children);
       }

       Lst_Done(&examine);
}

/* Make the .WAIT node depend on the previous children */
static void
AddWaitDependency(GNodeListNode *prevWaitNode, GNode *waitNode)
{
       GNodeListNode *ln;

       for (ln = prevWaitNode; ln->datum != waitNode; ln = ln->next) {
               GNode *gn = ln->datum;
               DEBUG3(MAKE, ".WAIT: add dependency \"%s: %s%s\"\n",
                   waitNode->name, gn->name, gn->cohort_num);
               Lst_Append(&waitNode->children, gn);
               Lst_Append(&gn->parents, waitNode);
               waitNode->unmade++;
       }
}

/* Convert .WAIT nodes into dependencies. */
static void
Make_ProcessWait(GNodeList *targets)
{
       GNode *pgn;             /* 'parent' node we are examining */
       GNodeList examine;

       /*
        * We need all the nodes to have a common parent in order for the
        * .WAIT and .ORDER scheduling to work.
        * Perhaps this should be done earlier...
        */

       pgn = GNode_New(".MAIN");
       pgn->flags.remake = true;
       pgn->type = OP_PHONY | OP_DEPENDS;
       /* Get it displayed in the diag dumps */
       Lst_Prepend(Targ_List(), pgn);

       {
               GNodeListNode *ln;
               for (ln = targets->first; ln != NULL; ln = ln->next) {
                       GNode *cgn = ln->datum;

                       Lst_Append(&pgn->children, cgn);
                       Lst_Append(&cgn->parents, pgn);
                       pgn->unmade++;
               }
       }

       /* Start building with the 'dummy' .MAIN' node */
       MakeBuildChild(pgn, NULL);

       Lst_Init(&examine);
       Lst_Append(&examine, pgn);

       while (!Lst_IsEmpty(&examine)) {
               GNodeListNode *waitNode, *ln;

               pgn = Lst_Dequeue(&examine);

               /* We only want to process each child-list once */
               if (pgn->flags.doneWait)
                       continue;
               pgn->flags.doneWait = true;
               DEBUG1(MAKE, "Make_ProcessWait: examine %s\n", pgn->name);

               if (pgn->type & OP_DOUBLEDEP)
                       Lst_PrependAll(&examine, &pgn->cohorts);

               waitNode = pgn->children.first;
               for (ln = pgn->children.first; ln != NULL; ln = ln->next) {
                       GNode *cgn = ln->datum;
                       if (cgn->type & OP_WAIT) {
                               AddWaitDependency(waitNode, cgn);
                               waitNode = ln;
                       } else
                               Lst_Append(&examine, cgn);
               }
       }

       Lst_Done(&examine);
}

bool
Make_MakeParallel(GNodeList *targets)
{
       int errors;             /* Number of errors the Job module reports */

       Lst_Init(&toBeMade);

       Make_ExpandUse(targets);
       Make_ProcessWait(targets);

       if (DEBUG(MAKE)) {
               debug_printf("#***# full graph\n");
               Targ_PrintGraph(1);
       }

       if (opts.query)
               return MakeStartJobs();

       (void)MakeStartJobs();
       while (!Lst_IsEmpty(&toBeMade) || jobTokensRunning > 0) {
               Job_CatchOutput();
               (void)MakeStartJobs();
       }

       errors = Job_Finish();

       DEBUG1(MAKE, "done: errors %d\n", errors);
       if (errors == 0) {
               MakePrintStatusList(targets, &errors);
               if (DEBUG(MAKE)) {
                       debug_printf("done: errors %d\n", errors);
                       if (errors > 0)
                               Targ_PrintGraph(4);
               }
       }
       return errors > 0;
}