Fix UTIME_OMIT handling

[dragonfly.git] / contrib / bmake / parse.c

/*      $NetBSD: parse.c,v 1.688 2022/09/27 17:46:58 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.
 */

/*
 * Parsing of makefiles.
 *
 * Parse_File is the main entry point and controls most of the other
 * functions in this module.
 *
 * Interface:
 *      Parse_Init      Initialize the module
 *
 *      Parse_End       Clean up the module
 *
 *      Parse_File      Parse a top-level makefile.  Included files are
 *                      handled by IncludeFile instead.
 *
 *      Parse_VarAssign
 *                      Try to parse the given line as a variable assignment.
 *                      Used by MainParseArgs to determine if an argument is
 *                      a target or a variable assignment.  Used internally
 *                      for pretty much the same thing.
 *
 *      Parse_Error     Report a parse error, a warning or an informational
 *                      message.
 *
 *      Parse_MainName  Returns a list of the single main target to create.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdarg.h>

#include "make.h"

#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif

#ifdef HAVE_MMAP
#include <sys/mman.h>

#ifndef MAP_COPY
#define MAP_COPY MAP_PRIVATE
#endif
#ifndef MAP_FILE
#define MAP_FILE 0
#endif
#endif

#include "dir.h"
#include "job.h"
#include "pathnames.h"

/*      "@(#)parse.c    8.3 (Berkeley) 3/19/94" */
MAKE_RCSID("$NetBSD: parse.c,v 1.688 2022/09/27 17:46:58 rillig Exp $");

/*
 * A file being read.
 */
typedef struct IncludedFile {
        FStr name;              /* absolute or relative to the cwd */
        unsigned lineno;        /* 1-based */
        unsigned readLines;     /* the number of physical lines that have
                                 * been read from the file */
        unsigned forHeadLineno; /* 1-based */
        unsigned forBodyReadLines; /* the number of physical lines that have
                                 * been read from the file above the body of
                                 * the .for loop */
        unsigned int condMinDepth; /* depth of nested 'if' directives, at the
                                 * beginning of the file */
        bool depending;         /* state of doing_depend on EOF */

        Buffer buf;             /* the file's content or the body of the .for
                                 * loop; either empty or ends with '\n' */
        char *buf_ptr;          /* next char to be read */
        char *buf_end;          /* buf_end[-1] == '\n' */

        struct ForLoop *forLoop;
} IncludedFile;

/* Special attributes for target nodes. */
typedef enum ParseSpecial {
        SP_ATTRIBUTE,   /* Generic attribute */
        SP_BEGIN,       /* .BEGIN */
        SP_DEFAULT,     /* .DEFAULT */
        SP_DELETE_ON_ERROR, /* .DELETE_ON_ERROR */
        SP_END,         /* .END */
        SP_ERROR,       /* .ERROR */
        SP_IGNORE,      /* .IGNORE */
        SP_INCLUDES,    /* .INCLUDES; not mentioned in the manual page */
        SP_INTERRUPT,   /* .INTERRUPT */
        SP_LIBS,        /* .LIBS; not mentioned in the manual page */
        SP_MAIN,        /* .MAIN and no user-specified targets to make */
        SP_META,        /* .META */
        SP_MFLAGS,      /* .MFLAGS or .MAKEFLAGS */
        SP_NOMETA,      /* .NOMETA */
        SP_NOMETA_CMP,  /* .NOMETA_CMP */
        SP_NOPATH,      /* .NOPATH */
        SP_NOT,         /* Not special */
        SP_NOTPARALLEL, /* .NOTPARALLEL or .NO_PARALLEL */
        SP_NULL,        /* .NULL; not mentioned in the manual page */
        SP_OBJDIR,      /* .OBJDIR */
        SP_ORDER,       /* .ORDER */
        SP_PARALLEL,    /* .PARALLEL; not mentioned in the manual page */
        SP_PATH,        /* .PATH or .PATH.suffix */
        SP_PHONY,       /* .PHONY */
#ifdef POSIX
        SP_POSIX,       /* .POSIX; not mentioned in the manual page */
#endif
        SP_PRECIOUS,    /* .PRECIOUS */
        SP_SHELL,       /* .SHELL */
        SP_SILENT,      /* .SILENT */
        SP_SINGLESHELL, /* .SINGLESHELL; not mentioned in the manual page */
        SP_STALE,       /* .STALE */
        SP_SUFFIXES,    /* .SUFFIXES */
        SP_WAIT         /* .WAIT */
} ParseSpecial;

typedef List SearchPathList;
typedef ListNode SearchPathListNode;


typedef enum VarAssignOp {
        VAR_NORMAL,             /* = */
        VAR_APPEND,             /* += */
        VAR_DEFAULT,            /* ?= */
        VAR_SUBST,              /* := */
        VAR_SHELL               /* != or :sh= */
} VarAssignOp;

typedef struct VarAssign {
        char *varname;          /* unexpanded */
        VarAssignOp op;
        const char *value;      /* unexpanded */
} VarAssign;

static bool Parse_IsVar(const char *, VarAssign *);
static void Parse_Var(VarAssign *, GNode *);

/*
 * The target to be made if no targets are specified in the command line.
 * This is the first target defined in any of the makefiles.
 */
GNode *mainNode;

/*
 * During parsing, the targets from the left-hand side of the currently
 * active dependency line, or NULL if the current line does not belong to a
 * dependency line, for example because it is a variable assignment.
 *
 * See unit-tests/deptgt.mk, keyword "parse.c:targets".
 */
static GNodeList *targets;

#ifdef CLEANUP
/*
 * All shell commands for all targets, in no particular order and possibly
 * with duplicates.  Kept in a separate list since the commands from .USE or
 * .USEBEFORE nodes are shared with other GNodes, thereby giving up the
 * easily understandable ownership over the allocated strings.
 */
static StringList targCmds = LST_INIT;
#endif

/*
 * Predecessor node for handling .ORDER. Initialized to NULL when .ORDER
 * is seen, then set to each successive source on the line.
 */
static GNode *order_pred;

static int parseErrors = 0;

/*
 * The include chain of makefiles.  At index 0 is the top-level makefile from
 * the command line, followed by the included files or .for loops, up to and
 * including the current file.
 *
 * See PrintStackTrace for how to interpret the data.
 */
static Vector /* of IncludedFile */ includes;

SearchPath *parseIncPath;       /* directories for "..." includes */
SearchPath *sysIncPath;         /* directories for <...> includes */
SearchPath *defSysIncPath;      /* default for sysIncPath */

/*
 * The parseKeywords table is searched using binary search when deciding
 * if a target or source is special. The 'spec' field is the ParseSpecial
 * type of the keyword (SP_NOT if the keyword isn't special as a target) while
 * the 'op' field is the operator to apply to the list of targets if the
 * keyword is used as a source ("0" if the keyword isn't special as a source)
 */
static const struct {
        const char name[17];
        ParseSpecial special;   /* when used as a target */
        GNodeType targetAttr;   /* when used as a source */
} parseKeywords[] = {
    { ".BEGIN",         SP_BEGIN,       OP_NONE },
    { ".DEFAULT",       SP_DEFAULT,     OP_NONE },
    { ".DELETE_ON_ERROR", SP_DELETE_ON_ERROR, OP_NONE },
    { ".END",           SP_END,         OP_NONE },
    { ".ERROR",         SP_ERROR,       OP_NONE },
    { ".EXEC",          SP_ATTRIBUTE,   OP_EXEC },
    { ".IGNORE",        SP_IGNORE,      OP_IGNORE },
    { ".INCLUDES",      SP_INCLUDES,    OP_NONE },
    { ".INTERRUPT",     SP_INTERRUPT,   OP_NONE },
    { ".INVISIBLE",     SP_ATTRIBUTE,   OP_INVISIBLE },
    { ".JOIN",          SP_ATTRIBUTE,   OP_JOIN },
    { ".LIBS",          SP_LIBS,        OP_NONE },
    { ".MADE",          SP_ATTRIBUTE,   OP_MADE },
    { ".MAIN",          SP_MAIN,        OP_NONE },
    { ".MAKE",          SP_ATTRIBUTE,   OP_MAKE },
    { ".MAKEFLAGS",     SP_MFLAGS,      OP_NONE },
    { ".META",          SP_META,        OP_META },
    { ".MFLAGS",        SP_MFLAGS,      OP_NONE },
    { ".NOMETA",        SP_NOMETA,      OP_NOMETA },
    { ".NOMETA_CMP",    SP_NOMETA_CMP,  OP_NOMETA_CMP },
    { ".NOPATH",        SP_NOPATH,      OP_NOPATH },
    { ".NOTMAIN",       SP_ATTRIBUTE,   OP_NOTMAIN },
    { ".NOTPARALLEL",   SP_NOTPARALLEL, OP_NONE },
    { ".NO_PARALLEL",   SP_NOTPARALLEL, OP_NONE },
    { ".NULL",          SP_NULL,        OP_NONE },
    { ".OBJDIR",        SP_OBJDIR,      OP_NONE },
    { ".OPTIONAL",      SP_ATTRIBUTE,   OP_OPTIONAL },
    { ".ORDER",         SP_ORDER,       OP_NONE },
    { ".PARALLEL",      SP_PARALLEL,    OP_NONE },
    { ".PATH",          SP_PATH,        OP_NONE },
    { ".PHONY",         SP_PHONY,       OP_PHONY },
#ifdef POSIX
    { ".POSIX",         SP_POSIX,       OP_NONE },
#endif
    { ".PRECIOUS",      SP_PRECIOUS,    OP_PRECIOUS },
    { ".RECURSIVE",     SP_ATTRIBUTE,   OP_MAKE },
    { ".SHELL",         SP_SHELL,       OP_NONE },
    { ".SILENT",        SP_SILENT,      OP_SILENT },
    { ".SINGLESHELL",   SP_SINGLESHELL, OP_NONE },
    { ".STALE",         SP_STALE,       OP_NONE },
    { ".SUFFIXES",      SP_SUFFIXES,    OP_NONE },
    { ".USE",           SP_ATTRIBUTE,   OP_USE },
    { ".USEBEFORE",     SP_ATTRIBUTE,   OP_USEBEFORE },
    { ".WAIT",          SP_WAIT,        OP_NONE },
};

enum PosixState posix_state = PS_NOT_YET;

static IncludedFile *
GetInclude(size_t i)
{
        assert(i < includes.len);
        return Vector_Get(&includes, i);
}

/* The file that is currently being read. */
static IncludedFile *
CurFile(void)
{
        return GetInclude(includes.len - 1);
}

unsigned int
CurFile_CondMinDepth(void)
{
        return CurFile()->condMinDepth;
}

static Buffer
LoadFile(const char *path, int fd)
{
        ssize_t n;
        Buffer buf;
        size_t bufSize;
        struct stat st;

        bufSize = fstat(fd, &st) == 0 && S_ISREG(st.st_mode) &&
                  st.st_size > 0 && st.st_size < 1024 * 1024 * 1024
            ? (size_t)st.st_size : 1024;
        Buf_InitSize(&buf, bufSize);

        for (;;) {
                if (buf.len == buf.cap) {
                        if (buf.cap >= 512 * 1024 * 1024) {
                                Error("%s: file too large", path);
                                exit(2); /* Not 1 so -q can distinguish error */
                        }
                        Buf_Expand(&buf);
                }
                assert(buf.len < buf.cap);
                n = read(fd, buf.data + buf.len, buf.cap - buf.len);
                if (n < 0) {
                        Error("%s: read error: %s", path, strerror(errno));
                        exit(2);        /* Not 1 so -q can distinguish error */
                }
                if (n == 0)
                        break;

                buf.len += (size_t)n;
        }
        assert(buf.len <= buf.cap);

        if (!Buf_EndsWith(&buf, '\n'))
                Buf_AddByte(&buf, '\n');

        return buf;             /* may not be null-terminated */
}

/*
 * Print the current chain of .include and .for directives.  In Parse_Fatal
 * or other functions that already print the location, includingInnermost
 * would be redundant, but in other cases like Error or Fatal it needs to be
 * included.
 */
void
PrintStackTrace(bool includingInnermost)
{
        const IncludedFile *entries;
        size_t i, n;

        n = includes.len;
        if (n == 0)
                return;

        entries = GetInclude(0);
        if (!includingInnermost && entries[n - 1].forLoop == NULL)
                n--;            /* already in the diagnostic */

        for (i = n; i-- > 0;) {
                const IncludedFile *entry = entries + i;
                const char *fname = entry->name.str;
                char dirbuf[MAXPATHLEN + 1];

                if (fname[0] != '/' && strcmp(fname, "(stdin)") != 0)
                        fname = realpath(fname, dirbuf);

                if (entry->forLoop != NULL) {
                        char *details = ForLoop_Details(entry->forLoop);
                        debug_printf("\tin .for loop from %s:%u with %s\n",
                            fname, entry->forHeadLineno, details);
                        free(details);
                } else if (i + 1 < n && entries[i + 1].forLoop != NULL) {
                        /* entry->lineno is not a useful line number */
                } else
                        debug_printf("\tin %s:%u\n", fname, entry->lineno);
        }
}

/* Check if the current character is escaped on the current line. */
static bool
IsEscaped(const char *line, const char *p)
{
        bool escaped = false;
        while (p > line && *--p == '\\')
                escaped = !escaped;
        return escaped;
}

/*
 * Add the filename and lineno to the GNode so that we remember where it
 * was first defined.
 */
static void
RememberLocation(GNode *gn)
{
        IncludedFile *curFile = CurFile();
        gn->fname = Str_Intern(curFile->name.str);
        gn->lineno = curFile->lineno;
}

/*
 * Look in the table of keywords for one matching the given string.
 * Return the index of the keyword, or -1 if it isn't there.
 */
static int
FindKeyword(const char *str)
{
        int start = 0;
        int end = sizeof parseKeywords / sizeof parseKeywords[0] - 1;

        while (start <= end) {
                int curr = start + (end - start) / 2;
                int diff = strcmp(str, parseKeywords[curr].name);

                if (diff == 0)
                        return curr;
                if (diff < 0)
                        end = curr - 1;
                else
                        start = curr + 1;
        }

        return -1;
}

void
PrintLocation(FILE *f, bool useVars, const GNode *gn)
{
        char dirbuf[MAXPATHLEN + 1];
        FStr dir, base;
        const char *fname;
        unsigned lineno;

        if (gn != NULL) {
                fname = gn->fname;
                lineno = gn->lineno;
        } else if (includes.len > 0) {
                IncludedFile *curFile = CurFile();
                fname = curFile->name.str;
                lineno = curFile->lineno;
        } else
                return;

        if (!useVars || fname[0] == '/' || strcmp(fname, "(stdin)") == 0) {
                (void)fprintf(f, "\"%s\" line %u: ", fname, lineno);
                return;
        }

        dir = Var_Value(SCOPE_GLOBAL, ".PARSEDIR");
        if (dir.str == NULL)
                dir.str = ".";
        if (dir.str[0] != '/')
                dir.str = realpath(dir.str, dirbuf);

        base = Var_Value(SCOPE_GLOBAL, ".PARSEFILE");
        if (base.str == NULL)
                base.str = str_basename(fname);

        (void)fprintf(f, "\"%s/%s\" line %u: ", dir.str, base.str, lineno);

        FStr_Done(&base);
        FStr_Done(&dir);
}

static void MAKE_ATTR_PRINTFLIKE(5, 0)
ParseVErrorInternal(FILE *f, bool useVars, const GNode *gn,
                    ParseErrorLevel level, const char *fmt, va_list ap)
{
        static bool fatal_warning_error_printed = false;

        (void)fprintf(f, "%s: ", progname);

        PrintLocation(f, useVars, gn);
        if (level == PARSE_WARNING)
                (void)fprintf(f, "warning: ");
        (void)vfprintf(f, fmt, ap);
        (void)fprintf(f, "\n");
        (void)fflush(f);

        if (level == PARSE_FATAL)
                parseErrors++;
        if (level == PARSE_WARNING && opts.parseWarnFatal) {
                if (!fatal_warning_error_printed) {
                        Error("parsing warnings being treated as errors");
                        fatal_warning_error_printed = true;
                }
                parseErrors++;
        }

        if (DEBUG(PARSE))
                PrintStackTrace(false);
}

static void MAKE_ATTR_PRINTFLIKE(3, 4)
ParseErrorInternal(const GNode *gn,
                   ParseErrorLevel level, const char *fmt, ...)
{
        va_list ap;

        (void)fflush(stdout);
        va_start(ap, fmt);
        ParseVErrorInternal(stderr, false, gn, level, fmt, ap);
        va_end(ap);

        if (opts.debug_file != stdout && opts.debug_file != stderr) {
                va_start(ap, fmt);
                ParseVErrorInternal(opts.debug_file, false, gn,
                    level, fmt, ap);
                va_end(ap);
        }
}

/*
 * Print a parse error message, including location information.
 *
 * If the level is PARSE_FATAL, continue parsing until the end of the
 * current top-level makefile, then exit (see Parse_File).
 *
 * Fmt is given without a trailing newline.
 */
void
Parse_Error(ParseErrorLevel level, const char *fmt, ...)
{
        va_list ap;

        (void)fflush(stdout);
        va_start(ap, fmt);
        ParseVErrorInternal(stderr, true, NULL, level, fmt, ap);
        va_end(ap);

        if (opts.debug_file != stdout && opts.debug_file != stderr) {
                va_start(ap, fmt);
                ParseVErrorInternal(opts.debug_file, true, NULL,
                    level, fmt, ap);
                va_end(ap);
        }
}


/*
 * Handle an .info, .warning or .error directive.  For an .error directive,
 * exit immediately.
 */
static void
HandleMessage(ParseErrorLevel level, const char *levelName, const char *umsg)
{
        char *xmsg;

        if (umsg[0] == '\0') {
                Parse_Error(PARSE_FATAL, "Missing argument for \".%s\"",
                    levelName);
                return;
        }

        (void)Var_Subst(umsg, SCOPE_CMDLINE, VARE_WANTRES, &xmsg);
        /* TODO: handle errors */

        Parse_Error(level, "%s", xmsg);
        free(xmsg);

        if (level == PARSE_FATAL) {
                PrintOnError(NULL, "\n");
                exit(1);
        }
}

/*
 * Add the child to the parent's children, and for non-special targets, vice
 * versa.  Special targets such as .END do not need to be informed once the
 * child target has been made.
 */
static void
LinkSource(GNode *pgn, GNode *cgn, bool isSpecial)
{
        if ((pgn->type & OP_DOUBLEDEP) && !Lst_IsEmpty(&pgn->cohorts))
                pgn = pgn->cohorts.last->datum;

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

        /* Special targets like .END don't need any children. */
        if (!isSpecial)
                Lst_Append(&cgn->parents, pgn);

        if (DEBUG(PARSE)) {
                debug_printf("# LinkSource: added child %s - %s\n",
                    pgn->name, cgn->name);
                Targ_PrintNode(pgn, 0);
                Targ_PrintNode(cgn, 0);
        }
}

/* Add the node to each target from the current dependency group. */
static void
LinkToTargets(GNode *gn, bool isSpecial)
{
        GNodeListNode *ln;

        for (ln = targets->first; ln != NULL; ln = ln->next)
                LinkSource(ln->datum, gn, isSpecial);
}

static bool
TryApplyDependencyOperator(GNode *gn, GNodeType op)
{
        /*
         * If the node occurred on the left-hand side of a dependency and the
         * operator also defines a dependency, they must match.
         */
        if ((op & OP_OPMASK) && (gn->type & OP_OPMASK) &&
            ((op & OP_OPMASK) != (gn->type & OP_OPMASK))) {
                Parse_Error(PARSE_FATAL, "Inconsistent operator for %s",
                    gn->name);
                return false;
        }

        if (op == OP_DOUBLEDEP && (gn->type & OP_OPMASK) == OP_DOUBLEDEP) {
                /*
                 * If the node was of the left-hand side of a '::' operator,
                 * we need to create a new instance of it for the children
                 * and commands on this dependency line since each of these
                 * dependency groups has its own attributes and commands,
                 * separate from the others.
                 *
                 * The new instance is placed on the 'cohorts' list of the
                 * initial one (note the initial one is not on its own
                 * cohorts list) and the new instance is linked to all
                 * parents of the initial instance.
                 */
                GNode *cohort;

                /*
                 * Propagate copied bits to the initial node.  They'll be
                 * propagated back to the rest of the cohorts later.
                 */
                gn->type |= op & (unsigned)~OP_OPMASK;

                cohort = Targ_NewInternalNode(gn->name);
                if (doing_depend)
                        RememberLocation(cohort);
                /*
                 * Make the cohort invisible as well to avoid duplicating it
                 * into other variables. True, parents of this target won't
                 * tend to do anything with their local variables, but better
                 * safe than sorry.
                 *
                 * (I think this is pointless now, since the relevant list
                 * traversals will no longer see this node anyway. -mycroft)
                 */
                cohort->type = op | OP_INVISIBLE;
                Lst_Append(&gn->cohorts, cohort);
                cohort->centurion = gn;
                gn->unmade_cohorts++;
                snprintf(cohort->cohort_num, sizeof cohort->cohort_num, "#%d",
                    (unsigned int)gn->unmade_cohorts % 1000000);
        } else {
                /*
                 * We don't want to nuke any previous flags (whatever they
                 * were) so we just OR the new operator into the old.
                 */
                gn->type |= op;
        }

        return true;
}

static void
ApplyDependencyOperator(GNodeType op)
{
        GNodeListNode *ln;

        for (ln = targets->first; ln != NULL; ln = ln->next)
                if (!TryApplyDependencyOperator(ln->datum, op))
                        break;
}

/*
 * We add a .WAIT node in the dependency list. After any dynamic dependencies
 * (and filename globbing) have happened, it is given a dependency on each
 * previous child, back until the previous .WAIT node. The next child won't
 * be scheduled until the .WAIT node is built.
 *
 * We give each .WAIT node a unique name (mainly for diagnostics).
 */
static void
ApplyDependencySourceWait(bool isSpecial)
{
        static unsigned wait_number = 0;
        char name[6 + 10 + 1];
        GNode *gn;

        snprintf(name, sizeof name, ".WAIT_%u", ++wait_number);
        gn = Targ_NewInternalNode(name);
        if (doing_depend)
                RememberLocation(gn);
        gn->type = OP_WAIT | OP_PHONY | OP_DEPENDS | OP_NOTMAIN;
        LinkToTargets(gn, isSpecial);
}

static bool
ApplyDependencySourceKeyword(const char *src, ParseSpecial special)
{
        int keywd;
        GNodeType targetAttr;

        if (*src != '.' || !ch_isupper(src[1]))
                return false;

        keywd = FindKeyword(src);
        if (keywd == -1)
                return false;

        targetAttr = parseKeywords[keywd].targetAttr;
        if (targetAttr != OP_NONE) {
                ApplyDependencyOperator(targetAttr);
                return true;
        }
        if (parseKeywords[keywd].special == SP_WAIT) {
                ApplyDependencySourceWait(special != SP_NOT);
                return true;
        }
        return false;
}

/*
 * In a line like ".MAIN: source1 source2", add all sources to the list of
 * things to create, but only if the user didn't specify a target on the
 * command line and .MAIN occurs for the first time.
 *
 * See HandleDependencyTargetSpecial, branch SP_MAIN.
 * See unit-tests/cond-func-make-main.mk.
 */
static void
ApplyDependencySourceMain(const char *src)
{
        Lst_Append(&opts.create, bmake_strdup(src));
        /*
         * Add the name to the .TARGETS variable as well, so the user can
         * employ that, if desired.
         */
        Global_Append(".TARGETS", src);
}

/*
 * For the sources of a .ORDER target, create predecessor/successor links
 * between the previous source and the current one.
 */
static void
ApplyDependencySourceOrder(const char *src)
{
        GNode *gn;

        gn = Targ_GetNode(src);
        if (doing_depend)
                RememberLocation(gn);
        if (order_pred != NULL) {
                Lst_Append(&order_pred->order_succ, gn);
                Lst_Append(&gn->order_pred, order_pred);
                if (DEBUG(PARSE)) {
                        debug_printf(
                            "# .ORDER forces '%s' to be made before '%s'\n",
                            order_pred->name, gn->name);
                        Targ_PrintNode(order_pred, 0);
                        Targ_PrintNode(gn, 0);
                }
        }
        /*
         * The current source now becomes the predecessor for the next one.
         */
        order_pred = gn;
}

/* The source is not an attribute, so find/create a node for it. */
static void
ApplyDependencySourceOther(const char *src, GNodeType targetAttr,
                           ParseSpecial special)
{
        GNode *gn;

        gn = Targ_GetNode(src);
        if (doing_depend)
                RememberLocation(gn);
        if (targetAttr != OP_NONE)
                gn->type |= targetAttr;
        else
                LinkToTargets(gn, special != SP_NOT);
}

/*
 * Given the name of a source in a dependency line, figure out if it is an
 * attribute (such as .SILENT) and if so, apply it to all targets. Otherwise
 * decide if there is some attribute which should be applied *to* the source
 * because of some special target (such as .PHONY) and apply it if so.
 * Otherwise, make the source a child of the targets.
 */
static void
ApplyDependencySource(GNodeType targetAttr, const char *src,
                      ParseSpecial special)
{
        if (ApplyDependencySourceKeyword(src, special))
                return;

        if (special == SP_MAIN)
                ApplyDependencySourceMain(src);
        else if (special == SP_ORDER)
                ApplyDependencySourceOrder(src);
        else
                ApplyDependencySourceOther(src, targetAttr, special);
}

/*
 * If we have yet to decide on a main target to make, in the absence of any
 * user input, we want the first target on the first dependency line that is
 * actually a real target (i.e. isn't a .USE or .EXEC rule) to be made.
 */
static void
MaybeUpdateMainTarget(void)
{
        GNodeListNode *ln;

        if (mainNode != NULL)
                return;

        for (ln = targets->first; ln != NULL; ln = ln->next) {
                GNode *gn = ln->datum;
                if (GNode_IsMainCandidate(gn)) {
                        DEBUG1(MAKE, "Setting main node to \"%s\"\n", gn->name);
                        mainNode = gn;
                        return;
                }
        }
}

static void
InvalidLineType(const char *line)
{
        if (strncmp(line, "<<<<<<", 6) == 0 ||
            strncmp(line, ">>>>>>", 6) == 0)
                Parse_Error(PARSE_FATAL,
                    "Makefile appears to contain unresolved CVS/RCS/??? merge conflicts");
        else if (line[0] == '.') {
                const char *dirstart = line + 1;
                const char *dirend;
                cpp_skip_whitespace(&dirstart);
                dirend = dirstart;
                while (ch_isalnum(*dirend) || *dirend == '-')
                        dirend++;
                Parse_Error(PARSE_FATAL, "Unknown directive \"%.*s\"",
                    (int)(dirend - dirstart), dirstart);
        } else
                Parse_Error(PARSE_FATAL, "Invalid line type");
}

static void
ParseDependencyTargetWord(char **pp, const char *lstart)
{
        const char *cp = *pp;

        while (*cp != '\0') {
                if ((ch_isspace(*cp) || *cp == '!' || *cp == ':' ||
                     *cp == '(') &&
                    !IsEscaped(lstart, cp))
                        break;

                if (*cp == '$') {
                        /*
                         * Must be a dynamic source (would have been expanded
                         * otherwise).
                         *
                         * There should be no errors in this, as they would
                         * have been discovered in the initial Var_Subst and
                         * we wouldn't be here.
                         */
                        FStr val;

                        (void)Var_Parse(&cp, SCOPE_CMDLINE,
                            VARE_PARSE_ONLY, &val);
                        FStr_Done(&val);
                } else
                        cp++;
        }

        *pp += cp - *pp;
}

/*
 * Handle special targets like .PATH, .DEFAULT, .BEGIN, .ORDER.
 *
 * See the tests deptgt-*.mk.
 */
static void
HandleDependencyTargetSpecial(const char *targetName,
                              ParseSpecial *inout_special,
                              SearchPathList **inout_paths)
{
        switch (*inout_special) {
        case SP_PATH:
                if (*inout_paths == NULL)
                        *inout_paths = Lst_New();
                Lst_Append(*inout_paths, &dirSearchPath);
                break;
        case SP_MAIN:
                /*
                 * Allow targets from the command line to override the
                 * .MAIN node.
                 */
                if (!Lst_IsEmpty(&opts.create))
                        *inout_special = SP_NOT;
                break;
        case SP_BEGIN:
        case SP_END:
        case SP_STALE:
        case SP_ERROR:
        case SP_INTERRUPT: {
                GNode *gn = Targ_GetNode(targetName);
                if (doing_depend)
                        RememberLocation(gn);
                gn->type |= OP_NOTMAIN | OP_SPECIAL;
                Lst_Append(targets, gn);
                break;
        }
        case SP_DEFAULT: {
                /*
                 * Need to create a node to hang commands on, but we don't
                 * want it in the graph, nor do we want it to be the Main
                 * Target. We claim the node is a transformation rule to make
                 * life easier later, when we'll use Make_HandleUse to
                 * actually apply the .DEFAULT commands.
                 */
                GNode *gn = GNode_New(".DEFAULT");
                gn->type |= OP_NOTMAIN | OP_TRANSFORM;
                Lst_Append(targets, gn);
                defaultNode = gn;
                break;
        }
        case SP_DELETE_ON_ERROR:
                deleteOnError = true;
                break;
        case SP_NOTPARALLEL:
                opts.maxJobs = 1;
                break;
        case SP_SINGLESHELL:
                opts.compatMake = true;
                break;
        case SP_ORDER:
                order_pred = NULL;
                break;
        default:
                break;
        }
}

static bool
HandleDependencyTargetPath(const char *suffixName,
                           SearchPathList **inout_paths)
{
        SearchPath *path;

        path = Suff_GetPath(suffixName);
        if (path == NULL) {
                Parse_Error(PARSE_FATAL,
                    "Suffix '%s' not defined (yet)", suffixName);
                return false;
        }

        if (*inout_paths == NULL)
                *inout_paths = Lst_New();
        Lst_Append(*inout_paths, path);

        return true;
}

/* See if it's a special target and if so set inout_special to match it. */
static bool
HandleDependencyTarget(const char *targetName,
                       ParseSpecial *inout_special,
                       GNodeType *inout_targetAttr,
                       SearchPathList **inout_paths)
{
        int keywd;

        if (!(targetName[0] == '.' && ch_isupper(targetName[1])))
                return true;

        /*
         * See if the target is a special target that must have it
         * or its sources handled specially.
         */
        keywd = FindKeyword(targetName);
        if (keywd != -1) {
                if (*inout_special == SP_PATH &&
                    parseKeywords[keywd].special != SP_PATH) {
                        Parse_Error(PARSE_FATAL, "Mismatched special targets");
                        return false;
                }

                *inout_special = parseKeywords[keywd].special;
                *inout_targetAttr = parseKeywords[keywd].targetAttr;

                HandleDependencyTargetSpecial(targetName, inout_special,
                    inout_paths);

        } else if (strncmp(targetName, ".PATH", 5) == 0) {
                *inout_special = SP_PATH;
                if (!HandleDependencyTargetPath(targetName + 5, inout_paths))
                        return false;
        }
        return true;
}

static void
HandleSingleDependencyTargetMundane(const char *name)
{
        GNode *gn = Suff_IsTransform(name)
            ? Suff_AddTransform(name)
            : Targ_GetNode(name);
        if (doing_depend)
                RememberLocation(gn);

        Lst_Append(targets, gn);
}

static void
HandleDependencyTargetMundane(const char *targetName)
{
        if (Dir_HasWildcards(targetName)) {
                StringList targetNames = LST_INIT;

                SearchPath *emptyPath = SearchPath_New();
                SearchPath_Expand(emptyPath, targetName, &targetNames);
                SearchPath_Free(emptyPath);

                while (!Lst_IsEmpty(&targetNames)) {
                        char *targName = Lst_Dequeue(&targetNames);
                        HandleSingleDependencyTargetMundane(targName);
                        free(targName);
                }
        } else
                HandleSingleDependencyTargetMundane(targetName);
}

static void
SkipExtraTargets(char **pp, const char *lstart)
{
        bool warning = false;
        const char *p = *pp;

        while (*p != '\0') {
                if (!IsEscaped(lstart, p) && (*p == '!' || *p == ':'))
                        break;
                if (IsEscaped(lstart, p) || (*p != ' ' && *p != '\t'))
                        warning = true;
                p++;
        }
        if (warning)
                Parse_Error(PARSE_WARNING, "Extra target ignored");

        *pp += p - *pp;
}

static void
CheckSpecialMundaneMixture(ParseSpecial special)
{
        switch (special) {
        case SP_DEFAULT:
        case SP_STALE:
        case SP_BEGIN:
        case SP_END:
        case SP_ERROR:
        case SP_INTERRUPT:
                /*
                 * These create nodes on which to hang commands, so targets
                 * shouldn't be empty.
                 */
        case SP_NOT:
                /* Nothing special here -- targets may be empty. */
                break;
        default:
                Parse_Error(PARSE_WARNING,
                    "Special and mundane targets don't mix. "
                    "Mundane ones ignored");
                break;
        }
}

/*
 * In a dependency line like 'targets: sources' or 'targets! sources', parse
 * the operator ':', '::' or '!' from between the targets and the sources.
 */
static GNodeType
ParseDependencyOp(char **pp)
{
        if (**pp == '!')
                return (*pp)++, OP_FORCE;
        if (**pp == ':' && (*pp)[1] == ':')
                return *pp += 2, OP_DOUBLEDEP;
        else if (**pp == ':')
                return (*pp)++, OP_DEPENDS;
        else
                return OP_NONE;
}

static void
ClearPaths(SearchPathList *paths)
{
        if (paths != NULL) {
                SearchPathListNode *ln;
                for (ln = paths->first; ln != NULL; ln = ln->next)
                        SearchPath_Clear(ln->datum);
        }

        Dir_SetPATH();
}

static char *
FindInDirOfIncludingFile(const char *file)
{
        char *fullname, *incdir, *slash, *newName;
        int i;

        fullname = NULL;
        incdir = bmake_strdup(CurFile()->name.str);
        slash = strrchr(incdir, '/');
        if (slash != NULL) {
                *slash = '\0';
                /*
                 * Now do lexical processing of leading "../" on the
                 * filename.
                 */
                for (i = 0; strncmp(file + i, "../", 3) == 0; i += 3) {
                        slash = strrchr(incdir + 1, '/');
                        if (slash == NULL || strcmp(slash, "/..") == 0)
                                break;
                        *slash = '\0';
                }
                newName = str_concat3(incdir, "/", file + i);
                fullname = Dir_FindFile(newName, parseIncPath);
                if (fullname == NULL)
                        fullname = Dir_FindFile(newName, &dirSearchPath);
                free(newName);
        }
        free(incdir);
        return fullname;
}

static char *
FindInQuotPath(const char *file)
{
        const char *suff;
        SearchPath *suffPath;
        char *fullname;

        fullname = FindInDirOfIncludingFile(file);
        if (fullname == NULL &&
            (suff = strrchr(file, '.')) != NULL &&
            (suffPath = Suff_GetPath(suff)) != NULL)
                fullname = Dir_FindFile(file, suffPath);
        if (fullname == NULL)
                fullname = Dir_FindFile(file, parseIncPath);
        if (fullname == NULL)
                fullname = Dir_FindFile(file, &dirSearchPath);
        return fullname;
}

/*
 * Handle one of the .[-ds]include directives by remembering the current file
 * and pushing the included file on the stack.  After the included file has
 * finished, parsing continues with the including file; see Parse_PushInput
 * and ParseEOF.
 *
 * System includes are looked up in sysIncPath, any other includes are looked
 * up in the parsedir and then in the directories specified by the -I command
 * line options.
 */
static void
IncludeFile(const char *file, bool isSystem, bool depinc, bool silent)
{
        Buffer buf;
        char *fullname;         /* full pathname of file */
        int fd;

        fullname = file[0] == '/' ? bmake_strdup(file) : NULL;

        if (fullname == NULL && !isSystem)
                fullname = FindInQuotPath(file);

        if (fullname == NULL) {
                SearchPath *path = Lst_IsEmpty(&sysIncPath->dirs)
                    ? defSysIncPath : sysIncPath;
                fullname = Dir_FindFile(file, path);
        }

        if (fullname == NULL) {
                if (!silent)
                        Parse_Error(PARSE_FATAL, "Could not find %s", file);
                return;
        }

        if ((fd = open(fullname, O_RDONLY)) == -1) {
                if (!silent)
                        Parse_Error(PARSE_FATAL, "Cannot open %s", fullname);
                free(fullname);
                return;
        }

        buf = LoadFile(fullname, fd);
        (void)close(fd);

        Parse_PushInput(fullname, 1, 0, buf, NULL);
        if (depinc)
                doing_depend = depinc;  /* only turn it on */
        free(fullname);
}

/* Handle a "dependency" line like '.SPECIAL:' without any sources. */
static void
HandleDependencySourcesEmpty(ParseSpecial special, SearchPathList *paths)
{
        switch (special) {
        case SP_SUFFIXES:
                Suff_ClearSuffixes();
                break;
        case SP_PRECIOUS:
                allPrecious = true;
                break;
        case SP_IGNORE:
                opts.ignoreErrors = true;
                break;
        case SP_SILENT:
                opts.silent = true;
                break;
        case SP_PATH:
                ClearPaths(paths);
                break;
#ifdef POSIX
        case SP_POSIX:
                if (posix_state == PS_NOW_OR_NEVER) {
                        /*
                         * With '-r', 'posix.mk' (if it exists)
                         * can effectively substitute for 'sys.mk',
                         * otherwise it is an extension.
                         */
                        Global_Set("%POSIX", "1003.2");
                        IncludeFile("posix.mk", true, false, true);
                }
                break;
#endif
        default:
                break;
        }
}

static void
AddToPaths(const char *dir, SearchPathList *paths)
{
        if (paths != NULL) {
                SearchPathListNode *ln;
                for (ln = paths->first; ln != NULL; ln = ln->next)
                        (void)SearchPath_Add(ln->datum, dir);
        }
}

/*
 * If the target was one that doesn't take files as its sources but takes
 * something like suffixes, we take each space-separated word on the line as
 * a something and deal with it accordingly.
 */
static void
ParseDependencySourceSpecial(ParseSpecial special, const char *word,
                             SearchPathList *paths)
{
        switch (special) {
        case SP_SUFFIXES:
                Suff_AddSuffix(word);
                break;
        case SP_PATH:
                AddToPaths(word, paths);
                break;
        case SP_INCLUDES:
                Suff_AddInclude(word);
                break;
        case SP_LIBS:
                Suff_AddLib(word);
                break;
        case SP_NULL:
                Suff_SetNull(word);
                break;
        case SP_OBJDIR:
                Main_SetObjdir(false, "%s", word);
                break;
        default:
                break;
        }
}

static bool
ApplyDependencyTarget(char *name, char *nameEnd, ParseSpecial *inout_special,
                      GNodeType *inout_targetAttr,
                      SearchPathList **inout_paths)
{
        char savec = *nameEnd;
        *nameEnd = '\0';

        if (!HandleDependencyTarget(name, inout_special,
            inout_targetAttr, inout_paths))
                return false;

        if (*inout_special == SP_NOT && *name != '\0')
                HandleDependencyTargetMundane(name);
        else if (*inout_special == SP_PATH && *name != '.' && *name != '\0')
                Parse_Error(PARSE_WARNING, "Extra target (%s) ignored", name);

        *nameEnd = savec;
        return true;
}

static bool
ParseDependencyTargets(char **inout_cp,
                       const char *lstart,
                       ParseSpecial *inout_special,
                       GNodeType *inout_targetAttr,
                       SearchPathList **inout_paths)
{
        char *cp = *inout_cp;

        for (;;) {
                char *tgt = cp;

                ParseDependencyTargetWord(&cp, lstart);

                /*
                 * If the word is followed by a left parenthesis, it's the
                 * name of one or more files inside an archive.
                 */
                if (!IsEscaped(lstart, cp) && *cp == '(') {
                        cp = tgt;
                        if (!Arch_ParseArchive(&cp, targets, SCOPE_CMDLINE)) {
                                Parse_Error(PARSE_FATAL,
                                    "Error in archive specification: \"%s\"",
                                    tgt);
                                return false;
                        }
                        continue;
                }

                if (*cp == '\0') {
                        InvalidLineType(lstart);
                        return false;
                }

                if (!ApplyDependencyTarget(tgt, cp, inout_special,
                    inout_targetAttr, inout_paths))
                        return false;

                if (*inout_special != SP_NOT && *inout_special != SP_PATH)
                        SkipExtraTargets(&cp, lstart);
                else
                        pp_skip_whitespace(&cp);

                if (*cp == '\0')
                        break;
                if ((*cp == '!' || *cp == ':') && !IsEscaped(lstart, cp))
                        break;
        }

        *inout_cp = cp;
        return true;
}

static void
ParseDependencySourcesSpecial(char *start,
                              ParseSpecial special, SearchPathList *paths)
{
        char savec;

        while (*start != '\0') {
                char *end = start;
                while (*end != '\0' && !ch_isspace(*end))
                        end++;
                savec = *end;
                *end = '\0';
                ParseDependencySourceSpecial(special, start, paths);
                *end = savec;
                if (savec != '\0')
                        end++;
                pp_skip_whitespace(&end);
                start = end;
        }
}

static void
LinkVarToTargets(VarAssign *var)
{
        GNodeListNode *ln;

        for (ln = targets->first; ln != NULL; ln = ln->next)
                Parse_Var(var, ln->datum);
}

static bool
ParseDependencySourcesMundane(char *start,
                              ParseSpecial special, GNodeType targetAttr)
{
        while (*start != '\0') {
                char *end = start;
                VarAssign var;

                /*
                 * Check for local variable assignment,
                 * rest of the line is the value.
                 */
                if (Parse_IsVar(start, &var)) {
                        /*
                         * Check if this makefile has disabled
                         * setting local variables.
                         */
                        bool target_vars = GetBooleanExpr(
                            "${.MAKE.TARGET_LOCAL_VARIABLES}", true);

                        if (target_vars)
                                LinkVarToTargets(&var);
                        free(var.varname);
                        if (target_vars)
                                return true;
                }

                /*
                 * The targets take real sources, so we must beware of archive
                 * specifications (i.e. things with left parentheses in them)
                 * and handle them accordingly.
                 */
                for (; *end != '\0' && !ch_isspace(*end); end++) {
                        if (*end == '(' && end > start && end[-1] != '$') {
                                /*
                                 * Only stop for a left parenthesis if it
                                 * isn't at the start of a word (that'll be
                                 * for variable changes later) and isn't
                                 * preceded by a dollar sign (a dynamic
                                 * source).
                                 */
                                break;
                        }
                }

                if (*end == '(') {
                        GNodeList sources = LST_INIT;
                        if (!Arch_ParseArchive(&start, &sources,
                            SCOPE_CMDLINE)) {
                                Parse_Error(PARSE_FATAL,
                                    "Error in source archive spec \"%s\"",
                                    start);
                                return false;
                        }

                        while (!Lst_IsEmpty(&sources)) {
                                GNode *gn = Lst_Dequeue(&sources);
                                ApplyDependencySource(targetAttr, gn->name,
                                    special);
                        }
                        Lst_Done(&sources);
                        end = start;
                } else {
                        if (*end != '\0') {
                                *end = '\0';
                                end++;
                        }

                        ApplyDependencySource(targetAttr, start, special);
                }
                pp_skip_whitespace(&end);
                start = end;
        }
        return true;
}

/*
 * From a dependency line like 'targets: sources', parse the sources.
 *
 * See the tests depsrc-*.mk.
 */
static void
ParseDependencySources(char *p, GNodeType targetAttr,
                       ParseSpecial special, SearchPathList **inout_paths)
{
        if (*p == '\0') {
                HandleDependencySourcesEmpty(special, *inout_paths);
        } else if (special == SP_MFLAGS) {
                Main_ParseArgLine(p);
                return;
        } else if (special == SP_SHELL) {
                if (!Job_ParseShell(p)) {
                        Parse_Error(PARSE_FATAL,
                            "improper shell specification");
                        return;
                }
                return;
        } else if (special == SP_NOTPARALLEL || special == SP_SINGLESHELL ||
                   special == SP_DELETE_ON_ERROR) {
                return;
        }

        /* Now go for the sources. */
        if (special == SP_SUFFIXES || special == SP_PATH ||
            special == SP_INCLUDES || special == SP_LIBS ||
            special == SP_NULL || special == SP_OBJDIR) {
                ParseDependencySourcesSpecial(p, special, *inout_paths);
                if (*inout_paths != NULL) {
                        Lst_Free(*inout_paths);
                        *inout_paths = NULL;
                }
                if (special == SP_PATH)
                        Dir_SetPATH();
        } else {
                assert(*inout_paths == NULL);
                if (!ParseDependencySourcesMundane(p, special, targetAttr))
                        return;
        }

        MaybeUpdateMainTarget();
}

/*
 * Parse a dependency line consisting of targets, followed by a dependency
 * operator, optionally followed by sources.
 *
 * The nodes of the sources are linked as children to the nodes of the
 * targets. Nodes are created as necessary.
 *
 * The operator is applied to each node in the global 'targets' list,
 * which is where the nodes found for the targets are kept.
 *
 * The sources are parsed in much the same way as the targets, except
 * that they are expanded using the wildcarding scheme of the C-Shell,
 * and a target is created for each expanded word. Each of the resulting
 * nodes is then linked to each of the targets as one of its children.
 *
 * Certain targets and sources such as .PHONY or .PRECIOUS are handled
 * specially, see ParseSpecial.
 *
 * Transformation rules such as '.c.o' are also handled here, see
 * Suff_AddTransform.
 *
 * Upon return, the value of the line is unspecified.
 */
static void
ParseDependency(char *line)
{
        char *p;
        SearchPathList *paths;  /* search paths to alter when parsing a list
                                 * of .PATH targets */
        GNodeType targetAttr;   /* from special sources */
        ParseSpecial special;   /* in special targets, the children are
                                 * linked as children of the parent but not
                                 * vice versa */
        GNodeType op;

        DEBUG1(PARSE, "ParseDependency(%s)\n", line);
        p = line;
        paths = NULL;
        targetAttr = OP_NONE;
        special = SP_NOT;

        if (!ParseDependencyTargets(&p, line, &special, &targetAttr, &paths))
                goto out;

        if (!Lst_IsEmpty(targets))
                CheckSpecialMundaneMixture(special);

        op = ParseDependencyOp(&p);
        if (op == OP_NONE) {
                InvalidLineType(line);
                goto out;
        }
        ApplyDependencyOperator(op);

        pp_skip_whitespace(&p);

        ParseDependencySources(p, targetAttr, special, &paths);

out:
        if (paths != NULL)
                Lst_Free(paths);
}

/*
 * Determine the assignment operator and adjust the end of the variable
 * name accordingly.
 */
static VarAssign
AdjustVarassignOp(const char *name, const char *nameEnd, const char *op,
                  const char *value)
{
        VarAssignOp type;
        VarAssign va;

        if (op > name && op[-1] == '+') {
                op--;
                type = VAR_APPEND;

        } else if (op > name && op[-1] == '?') {
                op--;
                type = VAR_DEFAULT;

        } else if (op > name && op[-1] == ':') {
                op--;
                type = VAR_SUBST;

        } else if (op > name && op[-1] == '!') {
                op--;
                type = VAR_SHELL;

        } else {
                type = VAR_NORMAL;
#ifdef SUNSHCMD
                while (op > name && ch_isspace(op[-1]))
                        op--;

                if (op - name >= 3 && memcmp(op - 3, ":sh", 3) == 0) {
                        op -= 3;
                        type = VAR_SHELL;
                }
#endif
        }

        va.varname = bmake_strsedup(name, nameEnd < op ? nameEnd : op);
        va.op = type;
        va.value = value;
        return va;
}

/*
 * Parse a variable assignment, consisting of a single-word variable name,
 * optional whitespace, an assignment operator, optional whitespace and the
 * variable value.
 *
 * Note: There is a lexical ambiguity with assignment modifier characters
 * in variable names. This routine interprets the character before the =
 * as a modifier. Therefore, an assignment like
 *      C++=/usr/bin/CC
 * is interpreted as "C+ +=" instead of "C++ =".
 *
 * Used for both lines in a file and command line arguments.
 */
static bool
Parse_IsVar(const char *p, VarAssign *out_var)
{
        const char *nameStart, *nameEnd, *firstSpace, *eq;
        int level = 0;

        cpp_skip_hspace(&p);    /* Skip to variable name */

        /*
         * During parsing, the '+' of the operator '+=' is initially parsed
         * as part of the variable name.  It is later corrected, as is the
         * ':sh' modifier. Of these two (nameEnd and eq), the earlier one
         * determines the actual end of the variable name.
         */

        nameStart = p;
        firstSpace = NULL;

        /*
         * Scan for one of the assignment operators outside a variable
         * expansion.
         */
        while (*p != '\0') {
                char ch = *p++;
                if (ch == '(' || ch == '{') {
                        level++;
                        continue;
                }
                if (ch == ')' || ch == '}') {
                        level--;
                        continue;
                }

                if (level != 0)
                        continue;

                if ((ch == ' ' || ch == '\t') && firstSpace == NULL)
                        firstSpace = p - 1;
                while (ch == ' ' || ch == '\t')
                        ch = *p++;

                if (ch == '\0')
                        return false;
#ifdef SUNSHCMD
                if (ch == ':' && p[0] == 's' && p[1] == 'h') {
                        p += 2;
                        continue;
                }
#endif
                if (ch == '=')
                        eq = p - 1;
                else if (*p == '=' &&
                    (ch == '+' || ch == ':' || ch == '?' || ch == '!'))
                        eq = p;
                else if (firstSpace != NULL)
                        return false;
                else
                        continue;

                nameEnd = firstSpace != NULL ? firstSpace : eq;
                p = eq + 1;
                cpp_skip_whitespace(&p);
                *out_var = AdjustVarassignOp(nameStart, nameEnd, eq, p);
                return true;
        }

        return false;
}

/*
 * Check for syntax errors such as unclosed expressions or unknown modifiers.
 */
static void
VarCheckSyntax(VarAssignOp type, const char *uvalue, GNode *scope)
{
        if (opts.strict) {
                if (type != VAR_SUBST && strchr(uvalue, '$') != NULL) {
                        char *expandedValue;

                        (void)Var_Subst(uvalue, scope, VARE_PARSE_ONLY,
                            &expandedValue);
                        /* TODO: handle errors */
                        free(expandedValue);
                }
        }
}

/* Perform a variable assignment that uses the operator ':='. */
static void
VarAssign_EvalSubst(GNode *scope, const char *name, const char *uvalue,
                    FStr *out_avalue)
{
        char *evalue;

        /*
         * make sure that we set the variable the first time to nothing
         * so that it gets substituted.
         *
         * TODO: Add a test that demonstrates why this code is needed,
         *  apart from making the debug log longer.
         *
         * XXX: The variable name is expanded up to 3 times.
         */
        if (!Var_ExistsExpand(scope, name))
                Var_SetExpand(scope, name, "");

        (void)Var_Subst(uvalue, scope, VARE_KEEP_DOLLAR_UNDEF, &evalue);
        /* TODO: handle errors */

        Var_SetExpand(scope, name, evalue);

        *out_avalue = FStr_InitOwn(evalue);
}

/* Perform a variable assignment that uses the operator '!='. */
static void
VarAssign_EvalShell(const char *name, const char *uvalue, GNode *scope,
                    FStr *out_avalue)
{
        FStr cmd;
        char *output, *error;

        cmd = FStr_InitRefer(uvalue);
        Var_Expand(&cmd, SCOPE_CMDLINE, VARE_UNDEFERR);

        output = Cmd_Exec(cmd.str, &error);
        Var_SetExpand(scope, name, output);
        *out_avalue = FStr_InitOwn(output);
        if (error != NULL) {
                Parse_Error(PARSE_WARNING, "%s", error);
                free(error);
        }

        FStr_Done(&cmd);
}

/*
 * Perform a variable assignment.
 *
 * The actual value of the variable is returned in *out_true_avalue.
 * Especially for VAR_SUBST and VAR_SHELL this can differ from the literal
 * value.
 *
 * Return whether the assignment was actually performed, which is usually
 * the case.  It is only skipped if the operator is '?=' and the variable
 * already exists.
 */
static bool
VarAssign_Eval(const char *name, VarAssignOp op, const char *uvalue,
               GNode *scope, FStr *out_true_avalue)
{
        FStr avalue = FStr_InitRefer(uvalue);

        if (op == VAR_APPEND)
                Var_AppendExpand(scope, name, uvalue);
        else if (op == VAR_SUBST)
                VarAssign_EvalSubst(scope, name, uvalue, &avalue);
        else if (op == VAR_SHELL)
                VarAssign_EvalShell(name, uvalue, scope, &avalue);
        else {
                /* XXX: The variable name is expanded up to 2 times. */
                if (op == VAR_DEFAULT && Var_ExistsExpand(scope, name))
                        return false;

                /* Normal assignment -- just do it. */
                Var_SetExpand(scope, name, uvalue);
        }

        *out_true_avalue = avalue;
        return true;
}

static void
VarAssignSpecial(const char *name, const char *avalue)
{
        if (strcmp(name, MAKEOVERRIDES) == 0)
                Main_ExportMAKEFLAGS(false);    /* re-export MAKEFLAGS */
        else if (strcmp(name, ".CURDIR") == 0) {
                /*
                 * Someone is being (too?) clever...
                 * Let's pretend they know what they are doing and
                 * re-initialize the 'cur' CachedDir.
                 */
                Dir_InitCur(avalue);
                Dir_SetPATH();
        } else if (strcmp(name, MAKE_JOB_PREFIX) == 0)
                Job_SetPrefix();
        else if (strcmp(name, MAKE_EXPORTED) == 0)
                Var_ExportVars(avalue);
}

/* Perform the variable assignment in the given scope. */
static void
Parse_Var(VarAssign *var, GNode *scope)
{
        FStr avalue;            /* actual value (maybe expanded) */

        VarCheckSyntax(var->op, var->value, scope);
        if (VarAssign_Eval(var->varname, var->op, var->value, scope, &avalue)) {
                VarAssignSpecial(var->varname, avalue.str);
                FStr_Done(&avalue);
        }
}


/*
 * See if the command possibly calls a sub-make by using the variable
 * expressions ${.MAKE}, ${MAKE} or the plain word "make".
 */
static bool
MaybeSubMake(const char *cmd)
{
        const char *start;

        for (start = cmd; *start != '\0'; start++) {
                const char *p = start;
                char endc;

                /* XXX: What if progname != "make"? */
                if (strncmp(p, "make", 4) == 0)
                        if (start == cmd || !ch_isalnum(p[-1]))
                                if (!ch_isalnum(p[4]))
                                        return true;

                if (*p != '$')
                        continue;
                p++;

                if (*p == '{')
                        endc = '}';
                else if (*p == '(')
                        endc = ')';
                else
                        continue;
                p++;

                if (*p == '.')  /* Accept either ${.MAKE} or ${MAKE}. */
                        p++;

                if (strncmp(p, "MAKE", 4) == 0 && p[4] == endc)
                        return true;
        }
        return false;
}

/*
 * Append the command to the target node.
 *
 * The node may be marked as a submake node if the command is determined to
 * be that.
 */
static void
GNode_AddCommand(GNode *gn, char *cmd)
{
        /* Add to last (ie current) cohort for :: targets */
        if ((gn->type & OP_DOUBLEDEP) && gn->cohorts.last != NULL)
                gn = gn->cohorts.last->datum;

        /* if target already supplied, ignore commands */
        if (!(gn->type & OP_HAS_COMMANDS)) {
                Lst_Append(&gn->commands, cmd);
                if (MaybeSubMake(cmd))
                        gn->type |= OP_SUBMAKE;
                RememberLocation(gn);
        } else {
#if 0
                /* XXX: We cannot do this until we fix the tree */
                Lst_Append(&gn->commands, cmd);
                Parse_Error(PARSE_WARNING,
                    "overriding commands for target \"%s\"; "
                    "previous commands defined at %s: %u ignored",
                    gn->name, gn->fname, gn->lineno);
#else
                Parse_Error(PARSE_WARNING,
                    "duplicate script for target \"%s\" ignored",
                    gn->name);
                ParseErrorInternal(gn, PARSE_WARNING,
                    "using previous script for \"%s\" defined here",
                    gn->name);
#endif
        }
}

/*
 * Add a directory to the path searched for included makefiles bracketed
 * by double-quotes.
 */
void
Parse_AddIncludeDir(const char *dir)
{
        (void)SearchPath_Add(parseIncPath, dir);
}


/*
 * Parse a directive like '.include' or '.-include'.
 *
 * .include "user-makefile.mk"
 * .include <system-makefile.mk>
 */
static void
ParseInclude(char *directive)
{
        char endc;              /* '>' or '"' */
        char *p;
        bool silent = directive[0] != 'i';
        FStr file;

        p = directive + (silent ? 8 : 7);
        pp_skip_hspace(&p);

        if (*p != '"' && *p != '<') {
                Parse_Error(PARSE_FATAL,
                    ".include filename must be delimited by '\"' or '<'");
                return;
        }

        if (*p++ == '<')
                endc = '>';
        else
                endc = '"';
        file = FStr_InitRefer(p);

        /* Skip to matching delimiter */
        while (*p != '\0' && *p != endc)
                p++;

        if (*p != endc) {
                Parse_Error(PARSE_FATAL,
                    "Unclosed .include filename. '%c' expected", endc);
                return;
        }

        *p = '\0';

        Var_Expand(&file, SCOPE_CMDLINE, VARE_WANTRES);
        IncludeFile(file.str, endc == '>', directive[0] == 'd', silent);
        FStr_Done(&file);
}

/*
 * Split filename into dirname + basename, then assign these to the
 * given variables.
 */
static void
SetFilenameVars(const char *filename, const char *dirvar, const char *filevar)
{
        const char *slash, *basename;
        FStr dirname;

        slash = strrchr(filename, '/');
        if (slash == NULL) {
                dirname = FStr_InitRefer(curdir);
                basename = filename;
        } else {
                dirname = FStr_InitOwn(bmake_strsedup(filename, slash));
                basename = slash + 1;
        }

        Global_Set(dirvar, dirname.str);
        Global_Set(filevar, basename);

        DEBUG4(PARSE, "SetFilenameVars: ${%s} = `%s' ${%s} = `%s'\n",
            dirvar, dirname.str, filevar, basename);
        FStr_Done(&dirname);
}

/*
 * Return the immediately including file.
 *
 * This is made complicated since the .for loop is implemented as a special
 * kind of .include; see For_Run.
 */
static const char *
GetActuallyIncludingFile(void)
{
        size_t i;
        const IncludedFile *incs = GetInclude(0);

        for (i = includes.len; i >= 2; i--)
                if (incs[i - 1].forLoop == NULL)
                        return incs[i - 2].name.str;
        return NULL;
}

/* Set .PARSEDIR, .PARSEFILE, .INCLUDEDFROMDIR and .INCLUDEDFROMFILE. */
static void
SetParseFile(const char *filename)
{
        const char *including;

        SetFilenameVars(filename, ".PARSEDIR", ".PARSEFILE");

        including = GetActuallyIncludingFile();
        if (including != NULL) {
                SetFilenameVars(including,
                    ".INCLUDEDFROMDIR", ".INCLUDEDFROMFILE");
        } else {
                Global_Delete(".INCLUDEDFROMDIR");
                Global_Delete(".INCLUDEDFROMFILE");
        }
}

static bool
StrContainsWord(const char *str, const char *word)
{
        size_t strLen = strlen(str);
        size_t wordLen = strlen(word);
        const char *p;

        if (strLen < wordLen)
                return false;

        for (p = str; p != NULL; p = strchr(p, ' ')) {
                if (*p == ' ')
                        p++;
                if (p > str + strLen - wordLen)
                        return false;

                if (memcmp(p, word, wordLen) == 0 &&
                    (p[wordLen] == '\0' || p[wordLen] == ' '))
                        return true;
        }
        return false;
}

/*
 * XXX: Searching through a set of words with this linear search is
 * inefficient for variables that contain thousands of words.
 *
 * XXX: The paths in this list don't seem to be normalized in any way.
 */
static bool
VarContainsWord(const char *varname, const char *word)
{
        FStr val = Var_Value(SCOPE_GLOBAL, varname);
        bool found = val.str != NULL && StrContainsWord(val.str, word);
        FStr_Done(&val);
        return found;
}

/*
 * Track the makefiles we read - so makefiles can set dependencies on them.
 * Avoid adding anything more than once.
 *
 * Time complexity: O(n) per call, in total O(n^2), where n is the number
 * of makefiles that have been loaded.
 */
static void
TrackInput(const char *name)
{
        if (!VarContainsWord(MAKE_MAKEFILES, name))
                Global_Append(MAKE_MAKEFILES, name);
}


/* Parse from the given buffer, later return to the current file. */
void
Parse_PushInput(const char *name, unsigned lineno, unsigned readLines,
                Buffer buf, struct ForLoop *forLoop)
{
        IncludedFile *curFile;

        if (forLoop != NULL)
                name = CurFile()->name.str;
        else
                TrackInput(name);

        DEBUG3(PARSE, "Parse_PushInput: %s %s, line %u\n",
            forLoop != NULL ? ".for loop in": "file", name, lineno);

        curFile = Vector_Push(&includes);
        curFile->name = FStr_InitOwn(bmake_strdup(name));
        curFile->lineno = lineno;
        curFile->readLines = readLines;
        curFile->forHeadLineno = lineno;
        curFile->forBodyReadLines = readLines;
        curFile->buf = buf;
        curFile->depending = doing_depend;      /* restore this on EOF */
        curFile->forLoop = forLoop;

        if (forLoop != NULL && !For_NextIteration(forLoop, &curFile->buf))
                abort();        /* see For_Run */

        curFile->buf_ptr = curFile->buf.data;
        curFile->buf_end = curFile->buf.data + curFile->buf.len;
        curFile->condMinDepth = cond_depth;
        SetParseFile(name);
}

/* Check if the directive is an include directive. */
static bool
IsInclude(const char *dir, bool sysv)
{
        if (dir[0] == 's' || dir[0] == '-' || (dir[0] == 'd' && !sysv))
                dir++;

        if (strncmp(dir, "include", 7) != 0)
                return false;

        /* Space is not mandatory for BSD .include */
        return !sysv || ch_isspace(dir[7]);
}


#ifdef SYSVINCLUDE
/* Check if the line is a SYSV include directive. */
static bool
IsSysVInclude(const char *line)
{
        const char *p;

        if (!IsInclude(line, true))
                return false;

        /* Avoid interpreting a dependency line as an include */
        for (p = line; (p = strchr(p, ':')) != NULL;) {

                /* end of line -> it's a dependency */
                if (*++p == '\0')
                        return false;

                /* '::' operator or ': ' -> it's a dependency */
                if (*p == ':' || ch_isspace(*p))
                        return false;
        }
        return true;
}

/* Push to another file.  The line points to the word "include". */
static void
ParseTraditionalInclude(char *line)
{
        char *cp;               /* current position in file spec */
        bool done = false;
        bool silent = line[0] != 'i';
        char *file = line + (silent ? 8 : 7);
        char *all_files;

        DEBUG1(PARSE, "ParseTraditionalInclude: %s\n", file);

        pp_skip_whitespace(&file);

        (void)Var_Subst(file, SCOPE_CMDLINE, VARE_WANTRES, &all_files);
        /* TODO: handle errors */

        for (file = all_files; !done; file = cp + 1) {
                /* Skip to end of line or next whitespace */
                for (cp = file; *cp != '\0' && !ch_isspace(*cp); cp++)
                        continue;

                if (*cp != '\0')
                        *cp = '\0';
                else
                        done = true;

                IncludeFile(file, false, false, silent);
        }

        free(all_files);
}
#endif

#ifdef GMAKEEXPORT
/* Parse "export <variable>=<value>", and actually export it. */
static void
ParseGmakeExport(char *line)
{
        char *variable = line + 6;
        char *value;

        DEBUG1(PARSE, "ParseGmakeExport: %s\n", variable);

        pp_skip_whitespace(&variable);

        for (value = variable; *value != '\0' && *value != '='; value++)
                continue;

        if (*value != '=') {
                Parse_Error(PARSE_FATAL,
                    "Variable/Value missing from \"export\"");
                return;
        }
        *value++ = '\0';        /* terminate variable */

        /*
         * Expand the value before putting it in the environment.
         */
        (void)Var_Subst(value, SCOPE_CMDLINE, VARE_WANTRES, &value);
        /* TODO: handle errors */

        setenv(variable, value, 1);
        free(value);
}
#endif

/*
 * Called when EOF is reached in the current file. If we were reading an
 * include file or a .for loop, the includes stack is popped and things set
 * up to go back to reading the previous file at the previous location.
 *
 * Results:
 *      true to continue parsing, i.e. it had only reached the end of an
 *      included file, false if the main file has been parsed completely.
 */
static bool
ParseEOF(void)
{
        IncludedFile *curFile = CurFile();

        doing_depend = curFile->depending;
        if (curFile->forLoop != NULL &&
            For_NextIteration(curFile->forLoop, &curFile->buf)) {
                curFile->buf_ptr = curFile->buf.data;
                curFile->buf_end = curFile->buf.data + curFile->buf.len;
                curFile->readLines = curFile->forBodyReadLines;
                return true;
        }

        Cond_EndFile();

        FStr_Done(&curFile->name);
        Buf_Done(&curFile->buf);
        if (curFile->forLoop != NULL)
                ForLoop_Free(curFile->forLoop);
        Vector_Pop(&includes);

        if (includes.len == 0) {
                /* We've run out of input */
                Global_Delete(".PARSEDIR");
                Global_Delete(".PARSEFILE");
                Global_Delete(".INCLUDEDFROMDIR");
                Global_Delete(".INCLUDEDFROMFILE");
                return false;
        }

        curFile = CurFile();
        DEBUG2(PARSE, "ParseEOF: returning to file %s, line %u\n",
            curFile->name.str, curFile->readLines + 1);

        SetParseFile(curFile->name.str);
        return true;
}

typedef enum ParseRawLineResult {
        PRLR_LINE,
        PRLR_EOF,
        PRLR_ERROR
} ParseRawLineResult;

/*
 * Parse until the end of a line, taking into account lines that end with
 * backslash-newline.  The resulting line goes from out_line to out_line_end;
 * the line is not null-terminated.
 */
static ParseRawLineResult
ParseRawLine(IncludedFile *curFile, char **out_line, char **out_line_end,
             char **out_firstBackslash, char **out_commentLineEnd)
{
        char *line = curFile->buf_ptr;
        char *buf_end = curFile->buf_end;
        char *p = line;
        char *line_end = line;
        char *firstBackslash = NULL;
        char *commentLineEnd = NULL;
        ParseRawLineResult res = PRLR_LINE;

        curFile->readLines++;

        for (;;) {
                char ch;

                if (p == buf_end) {
                        res = PRLR_EOF;
                        break;
                }

                ch = *p;
                if (ch == '\0' || (ch == '\\' && p[1] == '\0')) {
                        Parse_Error(PARSE_FATAL, "Zero byte read from file");
                        return PRLR_ERROR;
                }

                /* Treat next character after '\' as literal. */
                if (ch == '\\') {
                        if (firstBackslash == NULL)
                                firstBackslash = p;
                        if (p[1] == '\n') {
                                curFile->readLines++;
                                if (p + 2 == buf_end) {
                                        line_end = p;
                                        *line_end = '\n';
                                        p += 2;
                                        continue;
                                }
                        }
                        p += 2;
                        line_end = p;
                        assert(p <= buf_end);
                        continue;
                }

                /*
                 * Remember the first '#' for comment stripping, unless
                 * the previous char was '[', as in the modifier ':[#]'.
                 */
                if (ch == '#' && commentLineEnd == NULL &&
                    !(p > line && p[-1] == '['))
                        commentLineEnd = line_end;

                p++;
                if (ch == '\n')
                        break;

                /* We are not interested in trailing whitespace. */
                if (!ch_isspace(ch))
                        line_end = p;
        }

        curFile->buf_ptr = p;
        *out_line = line;
        *out_line_end = line_end;
        *out_firstBackslash = firstBackslash;
        *out_commentLineEnd = commentLineEnd;
        return res;
}

/*
 * Beginning at start, unescape '\#' to '#' and replace backslash-newline
 * with a single space.
 */
static void
UnescapeBackslash(char *line, char *start)
{
        const char *src = start;
        char *dst = start;
        char *spaceStart = line;

        for (;;) {
                char ch = *src++;
                if (ch != '\\') {
                        if (ch == '\0')
                                break;
                        *dst++ = ch;
                        continue;
                }

                ch = *src++;
                if (ch == '\0') {
                        /* Delete '\\' at the end of the buffer. */
                        dst--;
                        break;
                }

                /* Delete '\\' from before '#' on non-command lines. */
                if (ch == '#' && line[0] != '\t')
                        *dst++ = ch;
                else if (ch == '\n') {
                        cpp_skip_hspace(&src);
                        *dst++ = ' ';
                } else {
                        /* Leave '\\' in the buffer for later. */
                        *dst++ = '\\';
                        *dst++ = ch;
                        /* Keep an escaped ' ' at the line end. */
                        spaceStart = dst;
                }
        }

        /* Delete any trailing spaces - eg from empty continuations */
        while (dst > spaceStart && ch_isspace(dst[-1]))
                dst--;
        *dst = '\0';
}

typedef enum LineKind {
        /*
         * Return the next line that is neither empty nor a comment.
         * Backslash line continuations are folded into a single space.
         * A trailing comment, if any, is discarded.
         */
        LK_NONEMPTY,

        /*
         * Return the next line, even if it is empty or a comment.
         * Preserve backslash-newline to keep the line numbers correct.
         *
         * Used in .for loops to collect the body of the loop while waiting
         * for the corresponding .endfor.
         */
        LK_FOR_BODY,

        /*
         * Return the next line that starts with a dot.
         * Backslash line continuations are folded into a single space.
         * A trailing comment, if any, is discarded.
         *
         * Used in .if directives to skip over irrelevant branches while
         * waiting for the corresponding .endif.
         */
        LK_DOT
} LineKind;

/*
 * Return the next "interesting" logical line from the current file.  The
 * returned string will be freed at the end of including the file.
 */
static char *
ReadLowLevelLine(LineKind kind)
{
        IncludedFile *curFile = CurFile();
        ParseRawLineResult res;
        char *line;
        char *line_end;
        char *firstBackslash;
        char *commentLineEnd;

        for (;;) {
                curFile->lineno = curFile->readLines + 1;
                res = ParseRawLine(curFile,
                    &line, &line_end, &firstBackslash, &commentLineEnd);
                if (res == PRLR_ERROR)
                        return NULL;

                if (line == line_end || line == commentLineEnd) {
                        if (res == PRLR_EOF)
                                return NULL;
                        if (kind != LK_FOR_BODY)
                                continue;
                }

                /* We now have a line of data */
                assert(ch_isspace(*line_end));
                *line_end = '\0';

                if (kind == LK_FOR_BODY)
                        return line;    /* Don't join the physical lines. */

                if (kind == LK_DOT && line[0] != '.')
                        continue;
                break;
        }

        if (commentLineEnd != NULL && line[0] != '\t')
                *commentLineEnd = '\0';
        if (firstBackslash != NULL)
                UnescapeBackslash(line, firstBackslash);
        return line;
}

static bool
SkipIrrelevantBranches(void)
{
        const char *line;

        while ((line = ReadLowLevelLine(LK_DOT)) != NULL) {
                if (Cond_EvalLine(line) == CR_TRUE)
                        return true;
                /*
                 * TODO: Check for typos in .elif directives such as .elsif
                 * or .elseif.
                 *
                 * This check will probably duplicate some of the code in
                 * ParseLine.  Most of the code there cannot apply, only
                 * ParseVarassign and ParseDependencyLine can, and to prevent
                 * code duplication, these would need to be called with a
                 * flag called onlyCheckSyntax.
                 *
                 * See directive-elif.mk for details.
                 */
        }

        return false;
}

static bool
ParseForLoop(const char *line)
{
        int rval;
        unsigned forHeadLineno;
        unsigned bodyReadLines;
        int forLevel;

        rval = For_Eval(line);
        if (rval == 0)
                return false;   /* Not a .for line */
        if (rval < 0)
                return true;    /* Syntax error - error printed, ignore line */

        forHeadLineno = CurFile()->lineno;
        bodyReadLines = CurFile()->readLines;

        /* Accumulate the loop body until the matching '.endfor'. */
        forLevel = 1;
        do {
                line = ReadLowLevelLine(LK_FOR_BODY);
                if (line == NULL) {
                        Parse_Error(PARSE_FATAL,
                            "Unexpected end of file in .for loop");
                        break;
                }
        } while (For_Accum(line, &forLevel));

        For_Run(forHeadLineno, bodyReadLines);
        return true;
}

/*
 * Read an entire line from the input file.
 *
 * Empty lines, .if and .for are completely handled by this function,
 * leaving only variable assignments, other directives, dependency lines
 * and shell commands to the caller.
 *
 * Return a line without trailing whitespace, or NULL for EOF.  The returned
 * string will be freed at the end of including the file.
 */
static char *
ReadHighLevelLine(void)
{
        char *line;

        for (;;) {
                line = ReadLowLevelLine(LK_NONEMPTY);
                if (posix_state == PS_MAYBE_NEXT_LINE)
                        posix_state = PS_NOW_OR_NEVER;
                else
                        posix_state = PS_TOO_LATE;
                if (line == NULL)
                        return NULL;

                if (line[0] != '.')
                        return line;

                switch (Cond_EvalLine(line)) {
                case CR_FALSE:  /* May also mean a syntax error. */
                        if (!SkipIrrelevantBranches())
                                return NULL;
                        continue;
                case CR_TRUE:
                        continue;
                case CR_ERROR:  /* Not a conditional line */
                        if (ParseForLoop(line))
                                continue;
                        break;
                }
                return line;
        }
}

static void
FinishDependencyGroup(void)
{
        GNodeListNode *ln;

        if (targets == NULL)
                return;

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

                Suff_EndTransform(gn);

                /*
                 * Mark the target as already having commands if it does, to
                 * keep from having shell commands on multiple dependency
                 * lines.
                 */
                if (!Lst_IsEmpty(&gn->commands))
                        gn->type |= OP_HAS_COMMANDS;
        }

        Lst_Free(targets);
        targets = NULL;
}

/* Add the command to each target from the current dependency spec. */
static void
ParseLine_ShellCommand(const char *p)
{
        cpp_skip_whitespace(&p);
        if (*p == '\0')
                return;         /* skip empty commands */

        if (targets == NULL) {
                Parse_Error(PARSE_FATAL,
                    "Unassociated shell command \"%s\"", p);
                return;
        }

        {
                char *cmd = bmake_strdup(p);
                GNodeListNode *ln;

                for (ln = targets->first; ln != NULL; ln = ln->next) {
                        GNode *gn = ln->datum;
                        GNode_AddCommand(gn, cmd);
                }
#ifdef CLEANUP
                Lst_Append(&targCmds, cmd);
#endif
        }
}

static void
HandleBreak(void)
{
        IncludedFile *curFile = CurFile();

        if (curFile->forLoop != NULL) {
                /* pretend we reached EOF */
                For_Break(curFile->forLoop);
                cond_depth = CurFile_CondMinDepth();
                ParseEOF();
        } else
                Parse_Error(PARSE_FATAL, "break outside of for loop");
}

/*
 * See if the line starts with one of the known directives, and if so, handle
 * the directive.
 */
static bool
ParseDirective(char *line)
{
        char *cp = line + 1;
        const char *arg;
        Substring dir;

        pp_skip_whitespace(&cp);
        if (IsInclude(cp, false)) {
                ParseInclude(cp);
                return true;
        }

        dir.start = cp;
        while (ch_islower(*cp) || *cp == '-')
                cp++;
        dir.end = cp;

        if (*cp != '\0' && !ch_isspace(*cp))
                return false;

        pp_skip_whitespace(&cp);
        arg = cp;

        if (Substring_Equals(dir, "break"))
                HandleBreak();
        else if (Substring_Equals(dir, "undef"))
                Var_Undef(arg);
        else if (Substring_Equals(dir, "export"))
                Var_Export(VEM_PLAIN, arg);
        else if (Substring_Equals(dir, "export-env"))
                Var_Export(VEM_ENV, arg);
        else if (Substring_Equals(dir, "export-literal"))
                Var_Export(VEM_LITERAL, arg);
        else if (Substring_Equals(dir, "unexport"))
                Var_UnExport(false, arg);
        else if (Substring_Equals(dir, "unexport-env"))
                Var_UnExport(true, arg);
        else if (Substring_Equals(dir, "info"))
                HandleMessage(PARSE_INFO, "info", arg);
        else if (Substring_Equals(dir, "warning"))
                HandleMessage(PARSE_WARNING, "warning", arg);
        else if (Substring_Equals(dir, "error"))
                HandleMessage(PARSE_FATAL, "error", arg);
        else
                return false;
        return true;
}

bool
Parse_VarAssign(const char *line, bool finishDependencyGroup, GNode *scope)
{
        VarAssign var;

        if (!Parse_IsVar(line, &var))
                return false;
        if (finishDependencyGroup)
                FinishDependencyGroup();
        Parse_Var(&var, scope);
        free(var.varname);
        return true;
}

static char *
FindSemicolon(char *p)
{
        int level = 0;

        for (; *p != '\0'; p++) {
                if (*p == '\\' && p[1] != '\0') {
                        p++;
                        continue;
                }

                if (*p == '$' && (p[1] == '(' || p[1] == '{'))
                        level++;
                else if (level > 0 && (*p == ')' || *p == '}'))
                        level--;
                else if (level == 0 && *p == ';')
                        break;
        }
        return p;
}

/*
 * dependency   -> [target...] op [source...] [';' command]
 * op           -> ':' | '::' | '!'
 */
static void
ParseDependencyLine(char *line)
{
        VarEvalMode emode;
        char *expanded_line;
        const char *shellcmd = NULL;

        /*
         * For some reason - probably to make the parser impossible -
         * a ';' can be used to separate commands from dependencies.
         * Attempt to skip over ';' inside substitution patterns.
         */
        {
                char *semicolon = FindSemicolon(line);
                if (*semicolon != '\0') {
                        /* Terminate the dependency list at the ';' */
                        *semicolon = '\0';
                        shellcmd = semicolon + 1;
                }
        }

        /*
         * We now know it's a dependency line so it needs to have all
         * variables expanded before being parsed.
         *
         * XXX: Ideally the dependency line would first be split into
         * its left-hand side, dependency operator and right-hand side,
         * and then each side would be expanded on its own.  This would
         * allow for the left-hand side to allow only defined variables
         * and to allow variables on the right-hand side to be undefined
         * as well.
         *
         * Parsing the line first would also prevent that targets
         * generated from variable expressions are interpreted as the
         * dependency operator, such as in "target${:U\:} middle: source",
         * in which the middle is interpreted as a source, not a target.
         */

        /*
         * In lint mode, allow undefined variables to appear in dependency
         * lines.
         *
         * Ideally, only the right-hand side would allow undefined variables
         * since it is common to have optional dependencies. Having undefined
         * variables on the left-hand side is more unusual though.  Since
         * both sides are expanded in a single pass, there is not much choice
         * what to do here.
         *
         * In normal mode, it does not matter whether undefined variables are
         * allowed or not since as of 2020-09-14, Var_Parse does not print
         * any parse errors in such a case. It simply returns the special
         * empty string var_Error, which cannot be detected in the result of
         * Var_Subst.
         */
        emode = opts.strict ? VARE_WANTRES : VARE_UNDEFERR;
        (void)Var_Subst(line, SCOPE_CMDLINE, emode, &expanded_line);
        /* TODO: handle errors */

        /* Need a fresh list for the target nodes */
        if (targets != NULL)
                Lst_Free(targets);
        targets = Lst_New();

        ParseDependency(expanded_line);
        free(expanded_line);

        if (shellcmd != NULL)
                ParseLine_ShellCommand(shellcmd);
}

static void
ParseLine(char *line)
{
        /*
         * Lines that begin with '.' can be pretty much anything:
         *      - directives like '.include' or '.if',
         *      - suffix rules like '.c.o:',
         *      - dependencies for filenames that start with '.',
         *      - variable assignments like '.tmp=value'.
         */
        if (line[0] == '.' && ParseDirective(line))
                return;

        if (line[0] == '\t') {
                ParseLine_ShellCommand(line + 1);
                return;
        }

#ifdef SYSVINCLUDE
        if (IsSysVInclude(line)) {
                /*
                 * It's an S3/S5-style "include".
                 */
                ParseTraditionalInclude(line);
                return;
        }
#endif

#ifdef GMAKEEXPORT
        if (strncmp(line, "export", 6) == 0 && ch_isspace(line[6]) &&
            strchr(line, ':') == NULL) {
                /*
                 * It's a Gmake "export".
                 */
                ParseGmakeExport(line);
                return;
        }
#endif

        if (Parse_VarAssign(line, true, SCOPE_GLOBAL))
                return;

        FinishDependencyGroup();

        ParseDependencyLine(line);
}

/*
 * Parse a top-level makefile, incorporating its content into the global
 * dependency graph.
 */
void
Parse_File(const char *name, int fd)
{
        char *line;
        Buffer buf;

        buf = LoadFile(name, fd != -1 ? fd : STDIN_FILENO);
        if (fd != -1)
                (void)close(fd);

        assert(targets == NULL);

        Parse_PushInput(name, 1, 0, buf, NULL);

        do {
                while ((line = ReadHighLevelLine()) != NULL) {
                        DEBUG2(PARSE, "Parsing line %u: %s\n",
                            CurFile()->lineno, line);
                        ParseLine(line);
                }
                /* Reached EOF, but it may be just EOF of an include file. */
        } while (ParseEOF());

        FinishDependencyGroup();

        if (parseErrors != 0) {
                (void)fflush(stdout);
                (void)fprintf(stderr,
                    "%s: Fatal errors encountered -- cannot continue\n",
                    progname);
                PrintOnError(NULL, "");
                exit(1);
        }
}

/* Initialize the parsing module. */
void
Parse_Init(void)
{
        mainNode = NULL;
        parseIncPath = SearchPath_New();
        sysIncPath = SearchPath_New();
        defSysIncPath = SearchPath_New();
        Vector_Init(&includes, sizeof(IncludedFile));
}

/* Clean up the parsing module. */
void
Parse_End(void)
{
#ifdef CLEANUP
        Lst_DoneCall(&targCmds, free);
        assert(targets == NULL);
        SearchPath_Free(defSysIncPath);
        SearchPath_Free(sysIncPath);
        SearchPath_Free(parseIncPath);
        assert(includes.len == 0);
        Vector_Done(&includes);
#endif
}


/*
 * Return a list containing the single main target to create.
 * If no such target exists, we Punt with an obnoxious error message.
 */
void
Parse_MainName(GNodeList *mainList)
{
        if (mainNode == NULL)
                Punt("no target to make.");

        Lst_Append(mainList, mainNode);
        if (mainNode->type & OP_DOUBLEDEP)
                Lst_AppendAll(mainList, &mainNode->cohorts);

        Global_Append(".TARGETS", mainNode->name);
}

int
Parse_NumErrors(void)
{
        return parseErrors;
}