i386-gen.c

Tiny C&C++,看看吧,也许用的着

               ind + 1, R_386_32);
        oad(0xb8, 0); /* mov %eax, xxx */
        sym = external_global_sym(TOK___bound_local_delete, &func_old_type, 0);
        greloc(cur_text_section, sym, 
               ind + 1, R_386_PC32);
        oad(0xe8, -4);
        o(0x585a); /* restore returned value, if any */
    }
#endif
    o(0xc9); /* leave */
    if (func_ret_sub == 0) {
        o(0xc3); /* ret */
    } else {
        o(0xc2); /* ret n */
        g(func_ret_sub);
        g(func_ret_sub >> 8);
    }
    /* align local size to word & save local variables */
    *(int *)(cur_text_section->data + func_sub_sp_offset) = (-loc + 3) & -4; 
}

/* generate a jump to a label */
int gjmp(int t)
{
    return psym(0xe9, t);
}

/* generate a jump to a fixed address */
void gjmp_addr(int a)
{
    int r;
    r = a - ind - 2;
    if (r == (char)r) {
        g(0xeb);
        g(r);
    } else {
        oad(0xe9, a - ind - 5);
    }
}

/* generate a test. set 'inv' to invert test. Stack entry is popped */
int gtst(int inv, int t)
{
    int v, *p;

    v = vtop->r & VT_VALMASK;
    if (v == VT_CMP) {
        /* fast case : can jump directly since flags are set */
        g(0x0f);
        t = psym((vtop->c.i - 16) ^ inv, t);
    } else if (v == VT_JMP || v == VT_JMPI) {
        /* && or || optimization */
        if ((v & 1) == inv) {
            /* insert vtop->c jump list in t */
            p = &vtop->c.i;
            while (*p != 0)
                p = (int *)(cur_text_section->data + *p);
            *p = t;
            t = vtop->c.i;
        } else {
            t = gjmp(t);
            gsym(vtop->c.i);
        }
    } else {
        if (is_float(vtop->type.t)) {
            vpushi(0);
            gen_op(TOK_NE);
        }
        if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
            /* constant jmp optimization */
            if ((vtop->c.i != 0) != inv) 
                t = gjmp(t);
        } else {
            v = gv(RC_INT);
            o(0x85);
            o(0xc0 + v * 9);
            g(0x0f);
            t = psym(0x85 ^ inv, t);
        }
    }
    vtop--;
    return t;
}

/* generate an integer binary operation */
void gen_opi(int op)
{
    int r, fr, opc, c;

    switch(op) {
    case '+':
    case TOK_ADDC1: /* add with carry generation */
        opc = 0;
    gen_op8:
        if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
            /* constant case */
            vswap();
            r = gv(RC_INT);
            vswap();
            c = vtop->c.i;
            if (c == (char)c) {
                /* XXX: generate inc and dec for smaller code ? */
                o(0x83);
                o(0xc0 | (opc << 3) | r);
                g(c);
            } else {
                o(0x81);
                oad(0xc0 | (opc << 3) | r, c);
            }
        } else {
            gv2(RC_INT, RC_INT);
            r = vtop[-1].r;
            fr = vtop[0].r;
            o((opc << 3) | 0x01);
            o(0xc0 + r + fr * 8); 
        }
        vtop--;
        if (op >= TOK_ULT && op <= TOK_GT) {
            vtop->r = VT_CMP;
            vtop->c.i = op;
        }
        break;
    case '-':
    case TOK_SUBC1: /* sub with carry generation */
        opc = 5;
        goto gen_op8;
    case TOK_ADDC2: /* add with carry use */
        opc = 2;
        goto gen_op8;
    case TOK_SUBC2: /* sub with carry use */
        opc = 3;
        goto gen_op8;
    case '&':
        opc = 4;
        goto gen_op8;
    case '^':
        opc = 6;
        goto gen_op8;
    case '|':
        opc = 1;
        goto gen_op8;
    case '*':
        gv2(RC_INT, RC_INT);
        r = vtop[-1].r;
        fr = vtop[0].r;
        vtop--;
        o(0xaf0f); /* imul fr, r */
        o(0xc0 + fr + r * 8);
        break;
    case TOK_SHL:
        opc = 4;
        goto gen_shift;
    case TOK_SHR:
        opc = 5;
        goto gen_shift;
    case TOK_SAR:
        opc = 7;
    gen_shift:
        opc = 0xc0 | (opc << 3);
        if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
            /* constant case */
            vswap();
            r = gv(RC_INT);
            vswap();
            c = vtop->c.i & 0x1f;
            o(0xc1); /* shl/shr/sar $xxx, r */
            o(opc | r);
            g(c);
        } else {
            /* we generate the shift in ecx */
            gv2(RC_INT, RC_ECX);
            r = vtop[-1].r;
            o(0xd3); /* shl/shr/sar %cl, r */
            o(opc | r);
        }
        vtop--;
        break;
    case '/':
    case TOK_UDIV:
    case TOK_PDIV:
    case '%':
    case TOK_UMOD:
    case TOK_UMULL:
        /* first operand must be in eax */
        /* XXX: need better constraint for second operand */
        gv2(RC_EAX, RC_ECX);
        r = vtop[-1].r;
        fr = vtop[0].r;
        vtop--;
        save_reg(TREG_EDX);
        if (op == TOK_UMULL) {
            o(0xf7); /* mul fr */
            o(0xe0 + fr);
            vtop->r2 = TREG_EDX;
            r = TREG_EAX;
        } else {
            if (op == TOK_UDIV || op == TOK_UMOD) {
                o(0xf7d231); /* xor %edx, %edx, div fr, %eax */
                o(0xf0 + fr);
            } else {
                o(0xf799); /* cltd, idiv fr, %eax */
                o(0xf8 + fr);
            }
            if (op == '%' || op == TOK_UMOD)
                r = TREG_EDX;
            else
                r = TREG_EAX;
        }
        vtop->r = r;
        break;
    default:
        opc = 7;
        goto gen_op8;
    }
}

/* generate a floating point operation 'v = t1 op t2' instruction. The
   two operands are guaranted to have the same floating point type */
/* XXX: need to use ST1 too */
void gen_opf(int op)
{
    int a, ft, fc, swapped, r;

    /* convert constants to memory references */
    if ((vtop[-1].r & (VT_VALMASK | VT_LVAL)) == VT_CONST) {
        vswap();
        gv(RC_FLOAT);
        vswap();
    }
    if ((vtop[0].r & (VT_VALMASK | VT_LVAL)) == VT_CONST)
        gv(RC_FLOAT);

    /* must put at least one value in the floating point register */
    if ((vtop[-1].r & VT_LVAL) &&
        (vtop[0].r & VT_LVAL)) {
        vswap();
        gv(RC_FLOAT);
        vswap();
    }
    swapped = 0;
    /* swap the stack if needed so that t1 is the register and t2 is
       the memory reference */
    if (vtop[-1].r & VT_LVAL) {
        vswap();
        swapped = 1;
    }
    if (op >= TOK_ULT && op <= TOK_GT) {
        /* load on stack second operand */
        load(TREG_ST0, vtop);
        save_reg(TREG_EAX); /* eax is used by FP comparison code */
        if (op == TOK_GE || op == TOK_GT)
            swapped = !swapped;
        else if (op == TOK_EQ || op == TOK_NE)
            swapped = 0;
        if (swapped)
            o(0xc9d9); /* fxch %st(1) */
        o(0xe9da); /* fucompp */
        o(0xe0df); /* fnstsw %ax */
        if (op == TOK_EQ) {
            o(0x45e480); /* and $0x45, %ah */
            o(0x40fC80); /* cmp $0x40, %ah */
        } else if (op == TOK_NE) {
            o(0x45e480); /* and $0x45, %ah */
            o(0x40f480); /* xor $0x40, %ah */
            op = TOK_NE;
        } else if (op == TOK_GE || op == TOK_LE) {
            o(0x05c4f6); /* test $0x05, %ah */
            op = TOK_EQ;
        } else {
            o(0x45c4f6); /* test $0x45, %ah */
            op = TOK_EQ;
        }
        vtop--;
        vtop->r = VT_CMP;
        vtop->c.i = op;
    } else {
        /* no memory reference possible for long double operations */
        if ((vtop->type.t & VT_BTYPE) == VT_LDOUBLE) {
            load(TREG_ST0, vtop);
            swapped = !swapped;
        }
        
        switch(op) {
        default:
        case '+':
            a = 0;
            break;
        case '-':
            a = 4;
            if (swapped)
                a++;
            break;
        case '*':
            a = 1;
            break;
        case '/':
            a = 6;
            if (swapped)
                a++;
            break;
        }
        ft = vtop->type.t;
        fc = vtop->c.ul;
        if ((ft & VT_BTYPE) == VT_LDOUBLE) {
            o(0xde); /* fxxxp %st, %st(1) */
            o(0xc1 + (a << 3));
        } else {
            /* if saved lvalue, then we must reload it */
            r = vtop->r;
            if ((r & VT_VALMASK) == VT_LLOCAL) {
                SValue v1;
                r = get_reg(RC_INT);
                v1.type.t = VT_INT;
                v1.r = VT_LOCAL | VT_LVAL;
                v1.c.ul = fc;
                load(r, &v1);
                fc = 0;
            }

            if ((ft & VT_BTYPE) == VT_DOUBLE)
                o(0xdc);
            else
                o(0xd8);
            gen_modrm(a, r, vtop->sym, fc);
        }
        vtop--;
    }
}

/* convert integers to fp 't' type. Must handle 'int', 'unsigned int'
   and 'long long' cases. */
void gen_cvt_itof(int t)
{
    save_reg(TREG_ST0);
    gv(RC_INT);
    if ((vtop->type.t & VT_BTYPE) == VT_LLONG) {
        /* signed long long to float/double/long double (unsigned case
           is handled generically) */
        o(0x50 + vtop->r2); /* push r2 */
        o(0x50 + (vtop->r & VT_VALMASK)); /* push r */
        o(0x242cdf); /* fildll (%esp) */
        o(0x08c483); /* add $8, %esp */
    } else if ((vtop->type.t & (VT_BTYPE | VT_UNSIGNED)) == 
               (VT_INT | VT_UNSIGNED)) {
        /* unsigned int to float/double/long double */
        o(0x6a); /* push $0 */
        g(0x00);
        o(0x50 + (vtop->r & VT_VALMASK)); /* push r */
        o(0x242cdf); /* fildll (%esp) */
        o(0x08c483); /* add $8, %esp */
    } else {
        /* int to float/double/long double */
        o(0x50 + (vtop->r & VT_VALMASK)); /* push r */
        o(0x2404db); /* fildl (%esp) */
        o(0x04c483); /* add $4, %esp */
    }
    vtop->r = TREG_ST0;
}

/* convert fp to int 't' type */
/* XXX: handle long long case */
void gen_cvt_ftoi(int t)
{
    int r, r2, size;
    Sym *sym;
    CType ushort_type;

    ushort_type.t = VT_SHORT | VT_UNSIGNED;

    gv(RC_FLOAT);
    if (t != VT_INT)
        size = 8;
    else 
        size = 4;
    
    o(0x2dd9); /* ldcw xxx */
    sym = external_global_sym(TOK___tcc_int_fpu_control, 
                              &ushort_type, VT_LVAL);
    greloc(cur_text_section, sym, 
           ind, R_386_32);
    gen_le32(0);
    
    oad(0xec81, size); /* sub $xxx, %esp */
    if (size == 4)
        o(0x1cdb); /* fistpl */
    else
        o(0x3cdf); /* fistpll */
    o(0x24);
    o(0x2dd9); /* ldcw xxx */
    sym = external_global_sym(TOK___tcc_fpu_control, 
                              &ushort_type, VT_LVAL);
    greloc(cur_text_section, sym, 
           ind, R_386_32);
    gen_le32(0);

    r = get_reg(RC_INT);
    o(0x58 + r); /* pop r */
    if (size == 8) {
        if (t == VT_LLONG) {
            vtop->r = r; /* mark reg as used */
            r2 = get_reg(RC_INT);
            o(0x58 + r2); /* pop r2 */
            vtop->r2 = r2;
        } else {
            o(0x04c483); /* add $4, %esp */
        }
    }
    vtop->r = r;
}

/* convert from one floating point type to another */
void gen_cvt_ftof(int t)
{
    /* all we have to do on i386 is to put the float in a register */
    gv(RC_FLOAT);
}

/* computed goto support */
void ggoto(void)
{
    gcall_or_jmp(1);
    vtop--;
}

/* bound check support functions */
#ifdef CONFIG_TCC_BCHECK

/* generate a bounded pointer addition */
void gen_bounded_ptr_add(void)
{
    Sym *sym;

    /* prepare fast i386 function call (args in eax and edx) */
    gv2(RC_EAX, RC_EDX);
    /* save all temporary registers */
    vtop -= 2;
    save_regs(0);
    /* do a fast function call */
    sym = external_global_sym(TOK___bound_ptr_add, &func_old_type, 0);
    greloc(cur_text_section, sym, 
           ind + 1, R_386_PC32);
    oad(0xe8, -4);
    /* returned pointer is in eax */
    vtop++;
    vtop->r = TREG_EAX | VT_BOUNDED;
    /* address of bounding function call point */
    vtop->c.ul = (cur_text_section->reloc->data_offset - sizeof(Elf32_Rel)); 
}

/* patch pointer addition in vtop so that pointer dereferencing is
   also tested */
void gen_bounded_ptr_deref(void)
{
    int func;
    int size, align;
    Elf32_Rel *rel;
    Sym *sym;

    size = 0;
    /* XXX: put that code in generic part of tcc */
    if (!is_float(vtop->type.t)) {
        if (vtop->r & VT_LVAL_BYTE)
            size = 1;
        else if (vtop->r & VT_LVAL_SHORT)
            size = 2;
    }
    if (!size)
        size = type_size(&vtop->type, &align);
    switch(size) {
    case  1: func = TOK___bound_ptr_indir1; break;
    case  2: func = TOK___bound_ptr_indir2; break;
    case  4: func = TOK___bound_ptr_indir4; break;
    case  8: func = TOK___bound_ptr_indir8; break;
    case 12: func = TOK___bound_ptr_indir12; break;
    case 16: func = TOK___bound_ptr_indir16; break;
    default:
        error("unhandled size when derefencing bounded pointer");
        func = 0;
        break;
    }

    /* patch relocation */
    /* XXX: find a better solution ? */
    rel = (Elf32_Rel *)(cur_text_section->reloc->data + vtop->c.ul);
    sym = external_global_sym(func, &func_old_type, 0);
    if (!sym->c)
        put_extern_sym(sym, NULL, 0, 0);
    rel->r_info = ELF32_R_INFO(sym->c, ELF32_R_TYPE(rel->r_info));
}
#endif

/* end of X86 code generator */
/*************************************************************/