lburg.c

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#include <assert.h>
#include <ctype.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include "lburg.h"

static char rcsid[] = "lburg.c - faked rcsid";

static char *prefix = "";
static int Tflag = 0;
static int ntnumber = 0;
static Nonterm start = 0;
static Term terms;
static Nonterm nts;
static Rule rules;
static int nrules;
static struct block {
    struct block *link;
} *memlist;         /* list of allocated blocks */

static char *stringf(char *fmt, ...);
static void print(char *fmt, ...);
static void ckreach(Nonterm p);
static void emitclosure(Nonterm nts);
static void emitcost(Tree t, char *v);
static void emitdefs(Nonterm nts, int ntnumber);
static void emitheader(void);
static void emitkids(Rule rules, int nrules);
static void emitnts(Rule rules, int nrules);
static void emitrecalc(char *pre, Term root, Term kid);
static void emitrecord(char *pre, Rule r, char *c, int cost);
static void emitrule(Nonterm nts);
static void emitlabel(Term terms, Nonterm start, int ntnumber);
static void emitstring(Rule rules);
static void emitstruct(Nonterm nts, int ntnumber);
static void emittest(Tree t, char *v, char *suffix);

int main(int argc, char *argv[]) {
    int c, i;
    Nonterm p;
    
    for (i = 1; i < argc; i++)
        if (strcmp(argv[i], "-T") == 0)
            Tflag = 1;
        else if (strncmp(argv[i], "-p", 2) == 0 && argv[i][2])
            prefix = &argv[i][2];
        else if (strncmp(argv[i], "-p", 2) == 0 && i + 1 < argc)
            prefix = argv[++i];
        else if (*argv[i] == '-' && argv[i][1]) {
            yyerror("usage: %s [-T | -p prefix]... [ [ input ] output ] \n",
                argv[0]);
            exit(1);
        } else if (infp == NULL) {
            if (strcmp(argv[i], "-") == 0)
                infp = stdin;
            else if ((infp = fopen(argv[i], "r")) == NULL) {
                yyerror("%s: can't read `%s'\n", argv[0], argv[i]);
                exit(1);
            }
        } else if (outfp == NULL) {
            if (strcmp(argv[i], "-") == 0)
                outfp = stdout;
            if ((outfp = fopen(argv[i], "w")) == NULL) {
                yyerror("%s: can't write `%s'\n", argv[0], argv[i]);
                exit(1);
            }
        }
    if (infp == NULL)
        infp = stdin;
    if (outfp == NULL)
        outfp = stdout;
    yyparse();
    if (start)
        ckreach(start);
    for (p = nts; p; p = p->link) {
        if (p->rules == NULL)
            yyerror("undefined nonterminal `%s'\n", p->name);
        if (!p->reached)
            yyerror("can't reach nonterminal `%s'\n", p->name);
    }
    emitheader();
    emitdefs(nts, ntnumber);
    emitstruct(nts, ntnumber);
    emitnts(rules, nrules);
    emitstring(rules);
    emitrule(nts);
    emitclosure(nts);
    if (start)
        emitlabel(terms, start, ntnumber);
    emitkids(rules, nrules);
    if (!feof(infp))
        while ((c = getc(infp)) != EOF)
            putc(c, outfp);
    while (memlist) {   /* for purify */
        struct block *q = memlist->link;
        free(memlist);
        memlist = q;
    }
    return errcnt > 0;
}

/* alloc - allocate nbytes or issue fatal error */
void *alloc(int nbytes) {
    struct block *p = calloc(1, sizeof *p + nbytes);

    if (p == NULL) {
        yyerror("out of memory\n");
        exit(1);
    }
    p->link = memlist;
    memlist = p;
    return p + 1;
}

/* stringf - format and save a string */
static char *stringf(char *fmt, ...) {
    va_list ap;
    char buf[512];

    va_start(ap, fmt);
    vsprintf(buf, fmt, ap);
    va_end(ap);
    return strcpy(alloc(strlen(buf) + 1), buf);
}   

struct entry {
    union {
        char *name;
        struct term t;
        struct nonterm nt;
    } sym;
    struct entry *link;
} *table[211];
#define HASHSIZE (sizeof table/sizeof table[0])

/* hash - return hash number for str */
static unsigned hash(char *str) {
    unsigned h = 0;

    while (*str)
        h = (h<<1) + *str++;
    return h;
}

/* lookup - lookup symbol name */
static void *lookup(char *name) {
    struct entry *p = table[hash(name)%HASHSIZE];

    for ( ; p; p = p->link)
        if (strcmp(name, p->sym.name) == 0)
            return &p->sym;
    return 0;
}

/* install - install symbol name */
static void *install(char *name) {
    struct entry *p = alloc(sizeof *p);
    int i = hash(name)%HASHSIZE;

    p->sym.name = name;
    p->link = table[i];
    table[i] = p;
    return &p->sym;
}

/* nonterm - create a new terminal id, if necessary */
Nonterm nonterm(char *id) {
    Nonterm p = lookup(id), *q = &nts;

    if (p && p->kind == NONTERM)
        return p;
    if (p && p->kind == TERM)
        yyerror("`%s' is a terminal\n", id);
    p = install(id);
    p->kind = NONTERM;
    p->number = ++ntnumber;
    if (p->number == 1)
        start = p;
    while (*q && (*q)->number < p->number)
        q = &(*q)->link;
    assert(*q == 0 || (*q)->number != p->number);
    p->link = *q;
    *q = p;
    return p;
}

/* term - create a new terminal id with external symbol number esn */
Term term(char *id, int esn) {
    Term p = lookup(id), *q = &terms;

    if (p)
        yyerror("redefinition of terminal `%s'\n", id);
    else
        p = install(id);
    p->kind = TERM;
    p->esn = esn;
    p->arity = -1;
    while (*q && (*q)->esn < p->esn)
        q = &(*q)->link;
    if (*q && (*q)->esn == p->esn)
        yyerror("duplicate external symbol number `%s=%d'\n",
            p->name, p->esn);
    p->link = *q;
    *q = p;
    return p;
}

/* tree - create & initialize a tree node with the given fields */
Tree tree(char *id, Tree left, Tree right) {
    Tree t = alloc(sizeof *t);
    Term p = lookup(id);
    int arity = 0;

    if (left && right)
        arity = 2;
    else if (left)
        arity = 1;
    if (p == NULL && arity > 0) {
        yyerror("undefined terminal `%s'\n", id);
        p = term(id, -1);
    } else if (p == NULL && arity == 0)
        p = (Term)nonterm(id);
    else if (p && p->kind == NONTERM && arity > 0) {
        yyerror("`%s' is a nonterminal\n", id);
        p = term(id, -1);
    }
    if (p->kind == TERM && p->arity == -1)
        p->arity = arity;
    if (p->kind == TERM && arity != p->arity)
        yyerror("inconsistent arity for terminal `%s'\n", id);
    t->op = p;
    t->nterms = p->kind == TERM;
    if ((t->left = left) != NULL)
        t->nterms += left->nterms;
    if ((t->right = right) != NULL)
        t->nterms += right->nterms;
    return t;
}

/* rule - create & initialize a rule with the given fields */
Rule rule(char *id, Tree pattern, char *template, char *code) {
    Rule r = alloc(sizeof *r), *q;
    Term p = pattern->op;
    char *end;

    r->lhs = nonterm(id);
    r->packed = ++r->lhs->lhscount;
    for (q = &r->lhs->rules; *q; q = &(*q)->decode)
        ;
    *q = r;
    r->pattern = pattern;
    r->ern = ++nrules;
    r->template = template;
    r->code = code;
    r->cost = strtol(code, &end, 10);
    if (*end) {
        r->cost = -1;
        r->code = stringf("(%s)", code);
    }
    if (p->kind == TERM) {
        for (q = &p->rules; *q; q = &(*q)->next)
            ;
        *q = r;
    } else if (pattern->left == NULL && pattern->right == NULL) {
        Nonterm p = pattern->op;
        r->chain = p->chain;
            p->chain = r;
        if (r->cost == -1)
            yyerror("illegal nonconstant cost `%s'\n", code);
    }
    for (q = &rules; *q; q = &(*q)->link)
        ;
    r->link = *q;
    *q = r;
    return r;
}

/* print - formatted output */
static void print(char *fmt, ...) {
    va_list ap;

    va_start(ap, fmt);
    for ( ; *fmt; fmt++)
        if (*fmt == '%')
            switch (*++fmt) {
            case 'd': fprintf(outfp, "%d", va_arg(ap, int)); break;
            case 's': fputs(va_arg(ap, char *), outfp); break;
            case 'P': fprintf(outfp, "%s_", prefix); break;
            case 'T': {
                Tree t = va_arg(ap, Tree);
                print("%S", t->op);
                if (t->left && t->right)
                    print("(%T,%T)", t->left, t->right);
                else if (t->left)
                    print("(%T)", t->left);
                break;
                }
            case 'R': {
                Rule r = va_arg(ap, Rule);
                print("%S: %T", r->lhs, r->pattern);
                break;
                }
            case 'S': fputs(va_arg(ap, Term)->name, outfp); break;
            case '1': case '2': case '3': case '4': case '5': {
                int n = *fmt - '0';
                while (n-- > 0)
                    putc('\t', outfp);
                break;
                }
            default: putc(*fmt, outfp); break;          
            }
        else
            putc(*fmt, outfp);
    va_end(ap);
}

/* reach - mark all nonterminals in tree t as reachable */
static void reach(Tree t) {
    Nonterm p = t->op;

    if (p->kind == NONTERM)
        if (!p->reached)
            ckreach(p);
    if (t->left)
        reach(t->left);
    if (t->right)
        reach(t->right);
}

/* ckreach - mark all nonterminals reachable from p */
static void ckreach(Nonterm p) {
    Rule r;

        p->reached = 1;
    for (r = p->rules; r; r = r->decode)
        reach(r->pattern);
}

/* emitcase - emit one case in function state */
static void emitcase(Term p, int ntnumber) {
    Rule r;

    print("%1case %d: /* %S */\n", p->esn, p);
    switch (p->arity) {
    case 0: case -1:
        break;
    case 1:
        print("%2%Plabel(LEFT_CHILD(a));\n");
        break;
    case 2:
        print("%2%Plabel(LEFT_CHILD(a));\n");
        print("%2%Plabel(RIGHT_CHILD(a));\n");
        break;
    default: assert(0);
    }
    for (r = p->rules; r; r = r->next) {
        char *indent = "\t\t\0";
        switch (p->arity) {
        case 0: case -1:
            print("%2/* %R */\n", r);
            if (r->cost == -1) {
                print("%2c = %s;\n", r->code);
                emitrecord("\t\t", r, "c", 0);
            } else
                emitrecord("\t\t", r, r->code, 0);
            break;
        case 1:
            if (r->pattern->nterms > 1) {
                print("%2if (%1/* %R */\n", r);
                emittest(r->pattern->left, "LEFT_CHILD(a)", " ");
                print("%2) {\n");
                indent = "\t\t\t";
            } else
                print("%2/* %R */\n", r);
            if (r->pattern->nterms == 2 && r->pattern->left
            &&  r->pattern->right == NULL)
                emitrecalc(indent, r->pattern->op, r->pattern->left->op);
            print("%sc = ", indent);
            emitcost(r->pattern->left, "LEFT_CHILD(a)");
            print("%s;\n", r->code);
            emitrecord(indent, r, "c", 0);
            if (indent[2])
                print("%2}\n");
            break;
        case 2:
            if (r->pattern->nterms > 1) {
                print("%2if (%1/* %R */\n", r);
                emittest(r->pattern->left,  "LEFT_CHILD(a)",
                    r->pattern->right->nterms ? " && " : " ");
                emittest(r->pattern->right, "RIGHT_CHILD(a)", " ");
                print("%2) {\n");
                indent = "\t\t\t";
            } else
                print("%2/* %R */\n", r);
            print("%sc = ", indent);
            emitcost(r->pattern->left,  "LEFT_CHILD(a)");
            emitcost(r->pattern->right, "RIGHT_CHILD(a)");
            print("%s;\n", r->code);
            emitrecord(indent, r, "c", 0);
            if (indent[2])
                print("%2}\n");
            break;
        default: assert(0);
        }
    }
    print("%2break;\n");
}

/* emitclosure - emit the closure functions */
static void emitclosure(Nonterm nts) {
    Nonterm p;

    for (p = nts; p; p = p->link)
        if (p->chain)
            print("static void %Pclosure_%S(NODEPTR_TYPE, int);\n", p);
    print("\n");
    for (p = nts; p; p = p->link)
        if (p->chain) {
            Rule r;
            print("static void %Pclosure_%S(NODEPTR_TYPE a, int c) {\n"
"%1struct %Pstate *p = STATE_LABEL(a);\n", p);
            for (r = p->chain; r; r = r->chain)
                emitrecord("\t", r, "c", r->cost);
            print("}\n\n");
        }
}

/* emitcost - emit cost computation for tree t */
static void emitcost(Tree t, char *v) {
    Nonterm p = t->op;

    if (p->kind == TERM) {
        if (t->left)
            emitcost(t->left,  stringf("LEFT_CHILD(%s)",  v));
        if (t->right)
            emitcost(t->right, stringf("RIGHT_CHILD(%s)", v));
    } else
        print("((struct %Pstate *)(%s->x.state))->cost[%P%S_NT] + ", v, p);
}

/* emitdefs - emit nonterminal defines and data structures */
static void emitdefs(Nonterm nts, int ntnumber) {
    Nonterm p;

    for (p = nts; p; p = p->link)
        print("#define %P%S_NT %d\n", p, p->number);
    print("\n");
    print("static char *%Pntname[] = {\n%10,\n");
    for (p = nts; p; p = p->link)
        print("%1\"%S\",\n", p);
    print("%10\n};\n\n");
}

/* emitheader - emit initial definitions */
static void emitheader(void) {
    time_t timer = time(NULL);

    print("/*\ngenerated at %sby %s\n*/\n", ctime(&timer), rcsid);
    print("static void %Pkids(NODEPTR_TYPE, int, NODEPTR_TYPE[]);\n");
    print("static void %Plabel(NODEPTR_TYPE);\n");
    print("static int %Prule(void*, int);\n\n");
}

/* computekids - compute paths to kids in tree t */
static char *computekids(Tree t, char *v, char *bp, int *ip) {
    Term p = t->op;

    if (p->kind == NONTERM) {
        sprintf(bp, "\t\tkids[%d] = %s;\n", (*ip)++, v);
        bp += strlen(bp);
    } else if (p->arity > 0) {
        bp = computekids(t->left, stringf("LEFT_CHILD(%s)", v), bp, ip);
        if (p->arity == 2)
            bp = computekids(t->right, stringf("RIGHT_CHILD(%s)", v), bp, ip);
    }
    return bp;
}

/* emitkids - emit _kids */
static void emitkids(Rule rules, int nrules) {
    int i;
    Rule r, *rc = alloc((nrules + 1 + 1)*sizeof *rc);
    char **str  = alloc((nrules + 1 + 1)*sizeof *str);

    for (i = 0, r = rules; r; r = r->link) {
        int j = 0;
        char buf[1024], *bp = buf;
        *computekids(r->pattern, "p", bp, &j) = 0;
        for (j = 0; str[j] && strcmp(str[j], buf); j++)
            ;
        if (str[j] == NULL)
            str[j] = strcpy(alloc(strlen(buf) + 1), buf);
        r->kids = rc[j];
        rc[j] = r;
    }
    print("static void %Pkids(NODEPTR_TYPE p, int eruleno, NODEPTR_TYPE kids[]) {\n"
"%1if (!p)\n%2fatal(\"%Pkids\", \"Null tree\\n\", 0);\n"
"%1if (!kids)\n%2fatal(\"%Pkids\", \"Null kids\\n\", 0);\n"
"%1switch (eruleno) {\n");
    for (i = 0; (r = rc[i]) != NULL; i++) {
        for ( ; r; r = r->kids)
            print("%1case %d: /* %R */\n", r->ern, r);
        print("%s%2break;\n", str[i]);
    }
    print("%1default:\n%2fatal(\"%Pkids\", \"Bad rule number %%d\\n\", eruleno);\n%1}\n}\n\n");
}

/* emitlabel - emit label function */
static void emitlabel(Term terms, Nonterm start, int ntnumber) {
    int i;
    Term p;

    print("static void %Plabel(NODEPTR_TYPE a) {\n%1int c;\n"
"%1struct %Pstate *p;\n\n"
"%1if (!a)\n%2fatal(\"%Plabel\", \"Null tree\\n\", 0);\n");
    print("%1STATE_LABEL(a) = p = allocate(sizeof *p, FUNC);\n"
"%1p->rule._stmt = 0;\n");
    for (i = 1; i <= ntnumber; i++)
        print("%1p->cost[%d] =\n", i);
    print("%20x7fff;\n%1switch (OP_LABEL(a)) {\n");
    for (p = terms; p; p = p->link)
        emitcase(p, ntnumber);
    print("%1default:\n"
"%2fatal(\"%Plabel\", \"Bad terminal %%d\\n\", OP_LABEL(a));\n%1}\n}\n\n");
}

/* computents - fill in bp with _nts vector for tree t */
static char *computents(Tree t, char *bp) {
    if (t) {
        Nonterm p = t->op;
        if (p->kind == NONTERM) {
            sprintf(bp, "%s_%s_NT, ", prefix, p->name);
            bp += strlen(bp);
        } else
            bp = computents(t->right, computents(t->left,  bp));
    }
    return bp;
}

/* emitnts - emit _nts ragged array */
static void emitnts(Rule rules, int nrules) {
    Rule r;
    int i, j, *nts = alloc((nrules + 1)*sizeof *nts);
    char **str = alloc((nrules + 1)*sizeof *str);

    for (i = 0, r = rules; r; r = r->link) {
        char buf[1024];
        *computents(r->pattern, buf) = 0;
        for (j = 0; str[j] && strcmp(str[j], buf); j++)
            ;
        if (str[j] == NULL) {
            print("static short %Pnts_%d[] = { %s0 };\n", j, buf);
            str[j] = strcpy(alloc(strlen(buf) + 1), buf);
        }
        nts[i++] = j;
    }
    print("\nstatic short *%Pnts[] = {\n");
    for (i = j = 0, r = rules; r; r = r->link) {
        for ( ; j < r->ern; j++)
            print("%10,%1/* %d */\n", j);
        print("%1%Pnts_%d,%1/* %d */\n", nts[i++], j++);
    }
    print("};\n\n");
}

/* emitrecalc - emit code that tests for recalculation of INDIR?(VREGP) */
static void emitrecalc(char *pre, Term root, Term kid) {
    if (root->kind == TERM && strncmp(root->name, "INDIR", 5) == 0
    &&   kid->kind == TERM &&  strcmp(kid->name,  "VREGP"   ) == 0) {
        Nonterm p;
        print("%sif (mayrecalc(a)) {\n", pre);
        print("%s%1struct %Pstate *q = a->syms[RX]->u.t.cse->x.state;\n", pre);
        for (p = nts; p; p = p->link) {
            print("%s%1if (q->cost[%P%S_NT] == 0) {\n", pre, p);
            print("%s%2p->cost[%P%S_NT] = 0;\n", pre, p);
            print("%s%2p->rule.%P%S = q->rule.%P%S;\n", pre, p, p);
            print("%s%1}\n", pre);
        }
        print("%s}\n", pre);
    }
}

/* emitrecord - emit code that tests for a winning match of rule r */
static void emitrecord(char *pre, Rule r, char *c, int cost) {
    if (Tflag)
        print("%s%Ptrace(a, %d, %s + %d, p->cost[%P%S_NT]);\n",
            pre, r->ern, c, cost, r->lhs);
    print("%sif (", pre);
    print("%s + %d < p->cost[%P%S_NT]) {\n"
"%s%1p->cost[%P%S_NT] = %s + %d;\n%s%1p->rule.%P%S = %d;\n",
        c, cost, r->lhs, pre, r->lhs, c, cost, pre, r->lhs,
        r->packed);
    if (r->lhs->chain)
        print("%s%1%Pclosure_%S(a, %s + %d);\n", pre, r->lhs, c, cost);
    print("%s}\n", pre);
}

/* emitrule - emit decoding vectors and _rule */
static void emitrule(Nonterm nts) {
    Nonterm p;

    for (p = nts; p; p = p->link) {
        Rule r;
        print("static short %Pdecode_%S[] = {\n%10,\n", p);
        for (r = p->rules; r; r = r->decode)
            print("%1%d,\n", r->ern);
        print("};\n\n");
    }
    print("static int %Prule(void *state, int goalnt) {\n"
"%1if (goalnt < 1 || goalnt > %d)\n%2fatal(\"%Prule\", \"Bad goal nonterminal %%d\\n\", goalnt);\n"
"%1if (!state)\n%2return 0;\n%1switch (goalnt) {\n", ntnumber);
    for (p = nts; p; p = p->link)
        print("%1case %P%S_NT:"
"%1return %Pdecode_%S[((struct %Pstate *)state)->rule.%P%S];\n", p, p, p);
    print("%1default:\n%2fatal(\"%Prule\", \"Bad goal nonterminal %%d\\n\", goalnt);\n%2return 0;\n%1}\n}\n\n");
}

/* emitstring - emit arrays of templates, instruction flags, and rules */
static void emitstring(Rule rules) {
    Rule r;

    print("static char *%Ptemplates[] = {\n");
    print("/* 0 */%10,\n");
    for (r = rules; r; r = r->link)
        print("/* %d */%1\"%s\",%1/* %R */\n", r->ern, r->template, r);
    print("};\n");
    print("\nstatic char %Pisinstruction[] = {\n");
    print("/* 0 */%10,\n");
    for (r = rules; r; r = r->link) {
        int len = strlen(r->template);
        print("/* %d */%1%d,%1/* %s */\n", r->ern,
            len >= 2 && r->template[len-2] == '\\' && r->template[len-1] == 'n',
            r->template);
    }
    print("};\n");
    print("\nstatic char *%Pstring[] = {\n");
    print("/* 0 */%10,\n");
    for (r = rules; r; r = r->link)
        print("/* %d */%1\"%R\",\n", r->ern, r);
    print("};\n\n");
}

/* emitstruct - emit the definition of the state structure */
static void emitstruct(Nonterm nts, int ntnumber) {
    print("struct %Pstate {\n%1short cost[%d];\n%1struct {\n", ntnumber + 1);
    for ( ; nts; nts = nts->link) {
        int n = 1, m = nts->lhscount;
        while ((m >>= 1) != 0)
            n++;        
        print("%2unsigned int %P%S:%d;\n", nts, n);
    }
    print("%1} rule;\n};\n\n");
}

/* emittest - emit clause for testing a match */
static void emittest(Tree t, char *v, char *suffix) {
    Term p = t->op;

    if (p->kind == TERM) {
        print("%3%s->op == %d%s/* %S */\n", v, p->esn,
            t->nterms > 1 ? " && " : suffix, p);
        if (t->left)
            emittest(t->left, stringf("LEFT_CHILD(%s)",  v),
                t->right && t->right->nterms ? " && " : suffix);
        if (t->right)
            emittest(t->right, stringf("RIGHT_CHILD(%s)", v), suffix);
    }
}

---