sym.c

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#include "c.h"
#include <stdio.h>


#define equalp(x) v.x == p->sym.u.c.v.x

struct table {
    int level;
    Table previous;
    struct entry {
        struct symbol sym;
        struct entry *link;
    } *buckets[256];
    Symbol all;
};
#define HASHSIZE NELEMS(((Table)0)->buckets)
static struct table
    cns = { CONSTANTS },
    ext = { GLOBAL },
    ids = { GLOBAL },
    tys = { GLOBAL };
Table constants   = &cns;
Table externals   = &ext;
Table identifiers = &ids;
Table globals     = &ids;
Table types       = &tys;
Table labels;
int level = GLOBAL;
static int tempid;
List loci, symbols;

Table table(Table tp, int level) {
    Table new;

    NEW0(new, FUNC);
    new->previous = tp;
    new->level = level;
    if (tp)
        new->all = tp->all;
    return new;
}
void foreach(Table tp, int lev, void (*apply)(Symbol, void *), void *cl) {
    assert(tp);
    while (tp && tp->level > lev)
        tp = tp->previous;
    if (tp && tp->level == lev) {
        Symbol p;
        Coordinate sav;
        sav = src;
        for (p = tp->all; p && p->scope == lev; p = p->up) {
            src = p->src;
            (*apply)(p, cl);
        }
        src = sav;
    }
}
void enterscope(void) {
    if (++level == LOCAL)
        tempid = 0;
}
void exitscope(void) {
    rmtypes(level);
    if (types->level == level)
        types = types->previous;
    if (identifiers->level == level) {
        if (Aflag >= 2) {
            int n = 0;
            Symbol p;
            for (p = identifiers->all; p && p->scope == level; p = p->up)
                if (++n > 127) {
                    warning("more than 127 identifiers declared in a block\n");
                    break;
                }
        }
        identifiers = identifiers->previous;
    }
    assert(level >= GLOBAL);
    --level;
}
Symbol install(const char *name, Table *tpp, int level, int arena) {
    Table tp = *tpp;
    struct entry *p;
    unsigned h = (unsigned long)name&(HASHSIZE-1);

    assert(level == 0 || level >= tp->level);
    if (level > 0 && tp->level < level)
        tp = *tpp = table(tp, level);
    NEW0(p, arena);
    p->sym.name = (char *)name;
    p->sym.scope = level;
    p->sym.up = tp->all;
    tp->all = &p->sym;
    p->link = tp->buckets[h];
    tp->buckets[h] = p;
    return &p->sym;
}
Symbol relocate(const char *name, Table src, Table dst) {
    struct entry *p, **q;
    Symbol *r;
    unsigned h = (unsigned long)name&(HASHSIZE-1);

    for (q = &src->buckets[h]; *q; q = &(*q)->link)
        if (name == (*q)->sym.name)
            break;
    assert(*q);
    /*
     Remove the entry from src's hash chain
      and from its list of all symbols.
    */
    p = *q;
    *q = (*q)->link;
    for (r = &src->all; *r && *r != &p->sym; r = &(*r)->up)
        ;
    assert(*r == &p->sym);
    *r = p->sym.up;
    /*
     Insert the entry into dst's hash chain
      and into its list of all symbols.
      Return the symbol-table entry.
    */
    p->link = dst->buckets[h];
    dst->buckets[h] = p;
    p->sym.up = dst->all;
    dst->all = &p->sym;
    return &p->sym;
}
Symbol lookup(const char *name, Table tp) {
    struct entry *p;
    unsigned h = (unsigned long)name&(HASHSIZE-1);

    assert(tp);
    do
        for (p = tp->buckets[h]; p; p = p->link)
            if (name == p->sym.name)
                return &p->sym;
    while ((tp = tp->previous) != NULL);
    return NULL;
}
int genlabel(int n) {
    static int label = 1;

    label += n;
    return label - n;
}
Symbol findlabel(int lab) {
    struct entry *p;
    unsigned h = lab&(HASHSIZE-1);

    for (p = labels->buckets[h]; p; p = p->link)
        if (lab == p->sym.u.l.label)
            return &p->sym;
    NEW0(p, FUNC);
    p->sym.name = stringd(lab);
    p->sym.scope = LABELS;
    p->sym.up = labels->all;
    labels->all = &p->sym;
    p->link = labels->buckets[h];
    labels->buckets[h] = p;
    p->sym.generated = 1;
    p->sym.u.l.label = lab;
    (*IR->defsymbol)(&p->sym);
    return &p->sym;
}
Symbol constant(Type ty, Value v) {
    struct entry *p;
    unsigned h = v.u&(HASHSIZE-1);

    ty = unqual(ty);
    for (p = constants->buckets[h]; p; p = p->link)
        if (eqtype(ty, p->sym.type, 1))
            switch (ty->op) {
            case INT:      if (equalp(i)) return &p->sym; break;
            case UNSIGNED: if (equalp(u)) return &p->sym; break;
            case FLOAT:    if (equalp(d)) return &p->sym; break;
            case FUNCTION: if (equalp(g)) return &p->sym; break;
            case ARRAY:
            case POINTER:  if (equalp(p)) return &p->sym; break;
            default: assert(0);
            }
    NEW0(p, PERM);
    p->sym.name = vtoa(ty, v);
    p->sym.scope = CONSTANTS;
    p->sym.type = ty;
    p->sym.sclass = STATIC;
    p->sym.u.c.v = v;
    p->link = constants->buckets[h];
    p->sym.up = constants->all;
    constants->all = &p->sym;
    constants->buckets[h] = p;
    if (ty->u.sym && !ty->u.sym->addressed)
        (*IR->defsymbol)(&p->sym);
    p->sym.defined = 1;
    return &p->sym;
}
Symbol intconst(int n) {
    Value v;

    v.i = n;
    return constant(inttype, v);
}
Symbol genident(int scls, Type ty, int lev) {
    Symbol p;

    NEW0(p, lev >= LOCAL ? FUNC : PERM);
    p->name = stringd(genlabel(1));
    p->scope = lev;
    p->sclass = scls;
    p->type = ty;
    p->generated = 1;
    if (lev == GLOBAL)
        (*IR->defsymbol)(p);
    return p;
}

Symbol temporary(int scls, Type ty) {
    Symbol p;

    NEW0(p, FUNC);
    p->name = stringd(++tempid);
    p->scope = level < LOCAL ? LOCAL : level;
    p->sclass = scls;
    p->type = ty;
    p->temporary = 1;
    p->generated = 1;
    return p;
}
Symbol newtemp(int sclass, int tc, int size) {
    Symbol p = temporary(sclass, btot(tc, size));

    (*IR->local)(p);
    p->defined = 1;
    return p;
}

Symbol allsymbols(Table tp) {
    return tp->all;
}

void locus(Table tp, Coordinate *cp) {
    loci    = append(cp, loci);
    symbols = append(allsymbols(tp), symbols);
}

void use(Symbol p, Coordinate src) {
    Coordinate *cp;

    NEW(cp, PERM);
    *cp = src;
    p->uses = append(cp, p->uses);
}
/* findtype - find type ty in identifiers */
Symbol findtype(Type ty) {
    Table tp = identifiers;
    int i;
    struct entry *p;

    assert(tp);
    do
        for (i = 0; i < HASHSIZE; i++)
            for (p = tp->buckets[i]; p; p = p->link)
                if (p->sym.type == ty && p->sym.sclass == TYPEDEF)
                    return &p->sym;
    while ((tp = tp->previous) != NULL);
    return NULL;
}

/* mkstr - make a string constant */
Symbol mkstr(char *str) {
    Value v;
    Symbol p;

    v.p = str;
    p = constant(array(chartype, strlen(v.p) + 1, 0), v);
    if (p->u.c.loc == NULL)
        p->u.c.loc = genident(STATIC, p->type, GLOBAL);
    return p;
}

/* mksymbol - make a symbol for name, install in &globals if sclass==EXTERN */
Symbol mksymbol(int sclass, const char *name, Type ty) {
    Symbol p;

    if (sclass == EXTERN)
        p = install(string(name), &globals, GLOBAL, PERM);
    else {
        NEW0(p, PERM);
        p->name = string(name);
        p->scope = GLOBAL;
    }
    p->sclass = sclass;
    p->type = ty;
    (*IR->defsymbol)(p);
    p->defined = 1;
    return p;
}

/* vtoa - return string for the constant v of type ty */
char *vtoa(Type ty, Value v) {
    char buf[50];

    ty = unqual(ty);
    switch (ty->op) {
    case INT:      return stringd(v.i);
    case UNSIGNED: return stringf((v.u&~0x7FFF) ? "0x%X" : "%U", v.u);
    case FLOAT:    return stringf("%g", (double)v.d);
    case ARRAY:
        if (ty->type == chartype || ty->type == signedchar
        ||  ty->type == unsignedchar)
            return v.p;
        return stringf("%p", v.p);
    case POINTER:  return stringf("%p", v.p);
    case FUNCTION: return stringf("%p", v.g);
    }
    assert(0); return NULL;
}

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