alpha.md

lcc,一个可变目标c语言编译器的源码

                break;
                }

        }
}

static void doarg(Node p) {
        p->syms[2] = intconst(mkactual(8, roundup(p->syms[0]->u.c.v.i,8)));
}

static void local(Symbol p) {
        if (askregvar(p, rmap(ttob(p->type))) == 0)
                mkauto(p);
}

static int bitcount(unsigned mask) {
        unsigned i, n = 0;

        for (i = 1; i; i <<= 1)
                if (mask&i)
                        n++;
        return n;
}

static void function(Symbol f, Symbol caller[], Symbol callee[], int ncalls) {
        int i, sizeargs, saved, sizefsave, sizeisave, varargs;
        Symbol r, argregs[6];

        usedmask[0] = usedmask[1] = 0;
        freemask[0] = freemask[1] = ~(unsigned)0;
        maxargoffset = offset = maxoffset = 0;

        for (i = 0; callee[i]; i++)
                ;
        varargs = variadic(f->type)
                || i > 0 && strcmp(callee[i-1]->name, "va_alist") == 0;
        if (varargs)
                sizeargs = 2*48;
        else
                sizeargs = 48;

        for (i = 0; callee[i]; i++) {
                Symbol p = callee[i];
                Symbol q = caller[i];
                assert(q);
                if (isfloat(p->type) && varargs) {
                        p->x.offset = q->x.offset = offset - 2*48;
                        p->x.name = q->x.name = stringd(offset - 2*48);
                } else {
                        p->x.offset = q->x.offset = offset - 48;
                        p->x.name = q->x.name = stringd(offset - 48);
                }
                offset = roundup(offset, q->type->align);
                r = argreg(offset, optype(ttob(q->type)));
                if (i < 6)
                        argregs[i] = r;
                offset = roundup(offset + q->type->size, 8);
                if (varargs)
                        p->sclass = AUTO;
                else if (r && ncalls == 0 && !isstruct(q->type) && !p->addressed
) {
                        p->sclass = q->sclass = REGISTER;
                        askregvar(p, r);
                        assert(p->x.regnode && p->x.regnode->vbl == p);
                        q->x = p->x;
                        q->type = p->type;
                } else if (askregvar(p, rmap(ttob(p->type)))
                           && r != NULL /*
                           && (isint(p->type) || p->type == q->type) */
) {
                        assert(q->sclass != REGISTER);
                        p->sclass = q->sclass = REGISTER;
                        q->type = p->type;
                }

        }
        assert(!caller[i]);

        offset = sizeargs + 8;
        gencode(caller, callee);
        usedmask[IREG] &= ~(INTTMP|(0x3f<<16)|INTRET);
        usedmask[FREG] &= ~(FLTTMP|(0x3f<<16)|FLTRET);
        if (ncalls || usedmask[IREG] || usedmask[FREG])
                usedmask[IREG] |= 1<<26;
        sizefsave = 8*bitcount(usedmask[FREG]);
        sizeisave = 8*bitcount(usedmask[IREG]);
        if (maxargoffset > 48)
                maxargoffset -= 48;
        else
                maxargoffset = 0;
        if (maxoffset < sizeargs)
                maxoffset = sizeargs;
        framesize = roundup(maxargoffset + sizefsave + sizeisave + maxoffset, 16);
        segment(CODE);
        print(".ent %s\n", f->x.name);
        print("%s:\n", f->x.name);
        print("ldgp $gp,0($27)\n");
        i = maxargoffset + sizefsave - framesize;
        if (framesize > 0)
                print("lda $sp,%d($sp)\n", -framesize);
        if (usedmask[FREG])
                print(".fmask 0x%x,%d\n", usedmask[FREG], i - 8);
        if (usedmask[IREG])
                print(".mask 0x%x,%d\n",  usedmask[IREG], i + sizeisave - 8);
        print(".frame $sp,%d,$26,%d\n", framesize, sizeargs);

        saved = maxargoffset;
        for (i = 2; i <= 9; i++)
                if (usedmask[FREG]&(1<<i)) {
                        print("stt $f%d,%d($sp)\n", i, saved);
                        saved += 8;
                }

        for (i = 9; i <= 26; i++)
                if (usedmask[IREG]&(1<<i)) {
                        print("stq $%d,%d($sp)\n", i, saved);
                        saved += 8;
                }
        for (i = 0; i < 6 && callee[i]; i++) {
                r = argregs[i];
                if (r && r->x.regnode != callee[i]->x.regnode) {
                        Symbol out = callee[i];
                        Symbol in  = caller[i];
                        int rn = r->x.regnode->number;
                        int rs = r->x.regnode->set;
                        int tyin = ttob(in->type);

                        assert(out && in && r && r->x.regnode);
                        assert(out->sclass != REGISTER || out->x.regnode);
                        if (out->sclass == REGISTER) {
                                if (rs == FREG)
                                        print("fmov $f%d,$f%d\n", rn, out->x.regnode->number);
                                else
                                        print("mov $%d,$%d\n", rn, out->x.regnode->number);

                        } else {
                                int off = in->x.offset + framesize;
                                if (rs == FREG && tyin == F+sizeop(8))
                                        print("stt $f%d,%d($sp)\n", rn, off);
                                else if (rs == FREG && tyin == F+sizeop(4))
                                        print("sts $f%d,%d($sp)\n", rn, off);
                                else {
                                        int i, n = (in->type->size + 7)/8;
                                        for (i = rn; i < rn+n && i <= 21; i++)
                                                print("stq $%d,%d($sp)\n", i, off + (i-rn)*8);
                                }

                        }

                }
        }
        if (varargs && callee[i-1]) {
                i = callee[i-1]->x.offset + roundup(callee[i-1]->type->size, 8);
                for (i = (48+i)/8; i < 6; i++) {
                        print("stq $%d,%d($sp)\n",  i + 16, framesize -   48 + 8*i);
                        print("stt $f%d,%d($sp)\n", i + 16, framesize - 2*48 + 8*i);
                }
        }
        print(".prologue 1\n");

        emitcode();
        saved = maxargoffset;
        for (i = 2; i <= 9; i++)
                if (usedmask[FREG]&(1<<i)) {
                        print("ldt $f%d,%d($sp)\n", i, saved);
                        saved += 8;
                }
        for (i = 9; i <= 26; i++)
                if (usedmask[IREG]&(1<<i)) {
                        print("ldq $%d,%d($sp)\n", i, saved);
                        saved += 8;
                }
        if (framesize > 0)
                print("lda $sp,%d($sp)\n", framesize);
        print("ret\n");
        print(".end %s\n", f->x.name);

}

static void defconst(int suffix, int size, Value v) {
        if (suffix == F && size == 4) {
                float f = v.d;
                print(".long 0x%x\n", *(unsigned *)&f);
        } else if (suffix == F && size == 8) {
                double d = v.d;
                unsigned *p = (unsigned *)&d;
                print(".long 0x%x\n.long 0x%x\n", p[swap], p[!swap]);
        } else if (suffix == P)
                print(".quad 0x%X\n", v.p);
        else if (size == 1)
                print(".byte 0x%x\n", suffix == I ? v.i : v.u);
        else if (size == 2)
                print(".word 0x%x\n", suffix == I ? v.i&0xFFFF : v.u&0xFFFF);
        else if (size == 4)
                print(".long 0x%x\n", suffix == I ? v.i : v.u);
        else if (size == 8)
                print(".quad 0x%X\n", suffix == I ? v.i : v.u);

}

static void defaddress(Symbol p) {
        print(".quad %s\n", p->x.name);
}

static void defstring(int n, char *str) {
        char *s;

        for (s = str; s < str + n; s++)
                print(".byte %d\n", (*s)&0377);
}

static void export(Symbol p) {
        print(".globl %s\n", p->x.name);
}

static void import(Symbol p) {
        if (!isfunc(p->type))
                print(".extern %s %d\n", p->name, p->type->size);
}

static void defsymbol(Symbol p) {
        if (p->scope >= LOCAL && p->sclass == STATIC)
                p->x.name = stringf("L.%d", genlabel(1));
        else if (p->generated)
                p->x.name = stringf("L.%s", p->name);
        else
                assert(p->scope != CONSTANTS || isint(p->type) || isptr(p->type)),
                p->x.name = p->name;
}

static void address(Symbol q, Symbol p, long n) {
        if (p->scope == GLOBAL
        || p->sclass == STATIC || p->sclass == EXTERN)
                q->x.name = stringf("%s%s%D", p->x.name,
                        n >= 0 ? "+" : "", n);
        else {
                assert(n <= INT_MAX && n >= INT_MIN);
                q->x.offset = p->x.offset + n;
                q->x.name = stringd(q->x.offset);
        }
}

static void global(Symbol p) {
        if (p->u.seg == DATA || p->u.seg == LIT) {
                assert(p->type->align <= 8);
                print(".align %c\n", ".01.2...3"[p->type->align]);
                print("%s:\n", p->x.name);
        } else if (p->sclass == STATIC || Aflag >= 2)
                print(".lcomm %s,%d\n", p->x.name, p->type->size);
        else
                print( ".comm %s,%d\n", p->x.name, p->type->size);
}

static void segment(int n) {
        cseg = n;
        switch (n) {
        case DATA: print(".sdata\n"); break;
        case CODE: print(".text\n");  break;
        case LIT:  print(".rdata\n"); break;
        }
}

static void space(int n) {
        if (cseg != BSS)
                print(".space %d\n", n);
}

static void blkloop(int dreg, int doff, int sreg, int soff, int size, int tmps[]) {
        int lab = genlabel(1);

        print("addq $%d,%d,$%d\n",   sreg, size&~7, sreg);
        print("addq $%d,%d,$%d\n",   dreg, size&~7, tmps[2]);
        blkcopy(tmps[2], doff, sreg, soff, size&7, tmps);
        print("L.%d:\n", lab);
        print("addq $%d,%d,$%d\n",    sreg, -8, sreg);
        print("addq $%d,%d,$%d\n", tmps[2], -8, tmps[2]);
        blkcopy(tmps[2], doff, sreg, soff, 8, tmps);
        print("cmpult $%d,$%d,$23\nbne $23,L.%d\n", dreg, tmps[2], lab);
}

static void blkfetch(int size, int off, int reg, int tmp) {
        assert(size == 1 || size == 2 || size == 4 || size == 8);
        if (size == 1)
                print("ldb $%d,%d($%d)\n",  tmp, off, reg);
        else if (size == 2)
                print("ldw $%d,%d($%d)\n",  tmp, off, reg);
        else if (salign >= size && size == 4)
                print("ldl $%d,%d($%d)\n",  tmp, off, reg);
        else if (salign >= size && size == 8)
                print("ldq $%d,%d($%d)\n",  tmp, off, reg);
        else if (size == 4)
                print("uldl $%d,%d($%d)\n", tmp, off, reg);
        else
                print("uldq $%d,%d($%d)\n", tmp, off, reg);
}

static void blkstore(int size, int off, int reg, int tmp) {
        assert(size == 1 || size == 2 || size == 4 || size == 8);
        if (size == 1)
                print("stb $%d,%d($%d)\n",  tmp, off, reg);
        else if (size == 2)
                print("stw $%d,%d($%d)\n",  tmp, off, reg);
        else if (dalign >= size && size == 4)
                print("stl $%d,%d($%d)\n",  tmp, off, reg);
        else if (dalign >= size && size == 8)
                print("stq $%d,%d($%d)\n",  tmp, off, reg);
        else if (size == 4)
                print("ustl $%d,%d($%d)\n", tmp, off, reg);
        else
                print("ustq $%d,%d($%d)\n", tmp, off, reg);
}

/* stabinit - initialize stab output */
static void stabinit(char *file, int argc, char *argv[]) {
        if (file) {
                print(".file 2,\"%s\"\n", file);
                currentfile = file;
        }
}

/* stabline - emit stab entry for source coordinate *cp */
static void stabline(Coordinate *cp) {
        if (cp->file && cp->file != currentfile) {
                print(".file 2,\"%s\"\n", cp->file);
                currentfile = cp->file;
        }
        print(".loc 2,%d\n", cp->y);
}

/* stabsym - output a stab entry for symbol p */
static void stabsym(Symbol p) {
        if (p == cfunc && IR->stabline)
                (*IR->stabline)(&p->src);
}
Interface alphaIR = {
        1, 1, 0,  /* char */
        2, 2, 0,  /* short */
        4, 4, 0,  /* int */
        8, 8, 0,  /* long */
        8, 8, 0,  /* long long */
        4, 4, 1,  /* float */
        8, 8, 1,  /* double */
        8, 8, 1,  /* long double */
        8, 8, 0,  /* T * */
        0, 1, 0,  /* struct */

        1,      /* little_endian */
        0,  /* mulops_calls */
        0,  /* wants_callb */
        1,  /* wants_argb */
        1,  /* left_to_right */
        0,  /* wants_dag */
        0,  /* unsigned_char */
        address,
        blockbeg,
        blockend,
        defaddress,
        defconst,
        defstring,
        defsymbol,
        emit,
        export,
        function,
        gen,
        global,
        import,
        local,
        progbeg,
        progend,
        segment,
        space,
        0, 0, 0, stabinit, stabline, stabsym, 0,
        {
                1,      /* max_unaligned_load */
                rmap,
                blkfetch, blkstore, blkloop,
                _label,
                _rule,
                _nts,
                _kids,
                _string,
                _templates,
                _isinstruction,
                _ntname,
                emit2,
                doarg,
                target,
                clobber,

        }

};


static char rcsid[] = "$Id: alpha.md,v 1.1 2002/08/28 23:12:41 drh Exp $";