types.c

/*
 *  TccGen - The Tiny C Compiler backend
 *
 *  Copyright (c) 2001-2004 Fabrice Bellard
 *            (c) 2024 Rochus Keller
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "types.h"
#include "symbols.h"
#include "helper.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

/* return the pointed type of t */
CType *pointed_type(CType *type)
{
    return &type->ref->type;
}

/* return true if type1 and type2 are exactly the same (including
   qualifiers).
*/
int is_compatible_types(CType *type1, CType *type2)
{
    return compare_types(type1,type2,0);
}

/* return true if type1 and type2 are the same (ignoring qualifiers).
*/
int is_compatible_unqualified_types(CType *type1, CType *type2)
{
    return compare_types(type1,type2,1);
}

/* compare function types. OLD functions match any new functions */
static int is_compatible_func(CType *type1, CType *type2)
{
    Sym *s1, *s2;

    s1 = type1->ref;
    s2 = type2->ref;
    if (!is_compatible_types(&s1->type, &s2->type))
        return 0;
    /* check func_call */
    if (s1->f.func_call != s2->f.func_call)
        return 0;
    /* XXX: not complete */
    if (s1->f.func_type == FUNC_OLD || s2->f.func_type == FUNC_OLD)
        return 1;
    if (s1->f.func_type != s2->f.func_type)
        return 0;
    while (s1 != NULL) {
        if (s2 == NULL)
            return 0;
        if (!is_compatible_unqualified_types(&s1->type, &s2->type))
            return 0;
        s1 = s1->next;
        s2 = s2->next;
    }
    if (s2)
        return 0;
    return 1;
}

/* return true if type1 and type2 are the same.  If unqualified is
   true, qualifiers on the types are ignored.

   - enums are not checked as gcc __builtin_types_compatible_p ()
 */
int compare_types(CType *type1, CType *type2, int unqualified)
{
    int bt1, t1, t2;

    t1 = type1->t & VT_TYPE;
    t2 = type2->t & VT_TYPE;
    if (unqualified) {
        /* strip qualifiers before comparing */
        t1 &= ~(VT_CONSTANT | VT_VOLATILE);
        t2 &= ~(VT_CONSTANT | VT_VOLATILE);
    }

    /* Default Vs explicit signedness only matters for char */
    if ((t1 & VT_BTYPE) != VT_BYTE) {
        t1 &= ~VT_DEFSIGN;
        t2 &= ~VT_DEFSIGN;
    }
    /* XXX: bitfields ? */
    if (t1 != t2)
        return 0;
    /* test more complicated cases */
    bt1 = t1 & VT_BTYPE;
    if (bt1 == VT_PTR) {
        type1 = pointed_type(type1);
        type2 = pointed_type(type2);
        return is_compatible_types(type1, type2);
    } else if (bt1 == VT_STRUCT) {
        return (type1->ref == type2->ref);
    } else if (bt1 == VT_FUNC) {
        return is_compatible_func(type1, type2);
    } else {
        return 1;
    }
}

int is_float(int t)
{
    int bt;
    bt = t & VT_BTYPE;
    return bt == VT_LDOUBLE || bt == VT_DOUBLE || bt == VT_FLOAT || bt == VT_QFLOAT;
}

int is_integer_btype(int bt)
{
    return (bt == VT_BYTE || bt == VT_SHORT ||
            bt == VT_INT || bt == VT_LLONG);
}

/* return type size as known at compile time. Put alignment at 'a' */
int type_size(CType *type, int *a)
{
    Sym *s;
    int bt;

    bt = type->t & VT_BTYPE;
    if (bt == VT_STRUCT) {
        /* struct/union */
        s = type->ref;
        *a = s->r;
        return s->c;
    } else if (bt == VT_PTR) {
        if (type->t & VT_ARRAY) {
            int ts;

            s = type->ref;
            ts = type_size(&s->type, a);

            if (ts < 0 && s->c < 0)
                ts = -ts;

            return ts * s->c;
        } else {
            *a = PTR_SIZE;
            return PTR_SIZE;
        }
    } else if (IS_ENUM(type->t) && type->ref->c == -1) {
        return -1; /* incomplete enum */
    } else if (bt == VT_LDOUBLE) {
        *a = LDOUBLE_ALIGN;
        return LDOUBLE_SIZE;
    } else if (bt == VT_DOUBLE || bt == VT_LLONG) {
#ifdef TCC_TARGET_I386
#ifdef TCC_TARGET_PE
        *a = 8;
#else
        *a = 4;
#endif
#elif defined(TCC_TARGET_ARM)
#ifdef TCC_ARM_EABI
        *a = 8;
#else
        *a = 4;
#endif
#else
        *a = 8;
#endif
        return 8;
    } else if (bt == VT_INT || bt == VT_FLOAT) {
        *a = 4;
        return 4;
    } else if (bt == VT_SHORT) {
        *a = 2;
        return 2;
    } else if (bt == VT_QLONG || bt == VT_QFLOAT) {
        *a = 8;
        return 16;
    } else {
        /* char, void, function, _Bool */
        *a = 1;
        return 1;
    }
}

/* modify type so that its it is a pointer to type. */
void make_pointer(CType *type)
{
    Sym *s;
    s = sym_push(SYM_FIELD, type, 0, -1);
    type->t = VT_PTR | (type->t & VT_STORAGE);
    type->ref = s;
}


/* print a type. If 'varstr' is not NULL, then the variable is also
   printed in the type */
/* XXX: union */
/* XXX: add array and function pointers */
void type_to_str(char *buf, int buf_size,
                        CType *type, const char *varstr)
{
    int bt, v, t;
    Sym *s, *sa;
    char buf1[256];
    const char *tstr;

    t = type->t;
    bt = t & VT_BTYPE;
    buf[0] = '\0';

    if (t & VT_EXTERN)
        pstrcat(buf, buf_size, "extern ");
    if (t & VT_STATIC)
        pstrcat(buf, buf_size, "static ");
    if (t & VT_TYPEDEF)
        pstrcat(buf, buf_size, "typedef ");
    if (t & VT_INLINE)
        pstrcat(buf, buf_size, "inline ");
    if (t & VT_VOLATILE)
        pstrcat(buf, buf_size, "volatile ");
    if (t & VT_CONSTANT)
        pstrcat(buf, buf_size, "const ");

    if (((t & VT_DEFSIGN) && bt == VT_BYTE)
            || ((t & VT_UNSIGNED)
                && (bt == VT_SHORT || bt == VT_INT || bt == VT_LLONG)
                && !IS_ENUM(t)
                ))
        pstrcat(buf, buf_size, (t & VT_UNSIGNED) ? "unsigned " : "signed ");

    buf_size -= strlen(buf);
    buf += strlen(buf);

    switch(bt) {
    case VT_VOID:
        tstr = "void";
        goto add_tstr;
    case VT_BOOL:
        tstr = "_Bool";
        goto add_tstr;
    case VT_BYTE:
        tstr = "char";
        goto add_tstr;
    case VT_SHORT:
        tstr = "short";
        goto add_tstr;
    case VT_INT:
        tstr = "int";
        goto maybe_long;
    case VT_LLONG:
        tstr = "long long";
maybe_long:
        if (t & VT_LONG)
            tstr = "long";
        if (!IS_ENUM(t))
            goto add_tstr;
        tstr = "enum ";
        goto tstruct;
    case VT_FLOAT:
        tstr = "float";
        goto add_tstr;
    case VT_DOUBLE:
        tstr = "double";
        goto add_tstr;
    case VT_LDOUBLE:
        tstr = "long double";
add_tstr:
        pstrcat(buf, buf_size, tstr);
        break;
    case VT_STRUCT:
        tstr = "struct ";
        if (IS_UNION(t))
            tstr = "union ";
tstruct:
        pstrcat(buf, buf_size, tstr);
        v = type->ref->v & ~SYM_STRUCT;
        if (v >= SYM_FIRST_ANOM)
            pstrcat(buf, buf_size, "<anonymous>");
        else
            pstrcat(buf, buf_size, get_tok_str(v, NULL));
        break;
    case VT_FUNC:
        s = type->ref;
        type_to_str(buf, buf_size, &s->type, varstr);
        pstrcat(buf, buf_size, "(");
        sa = s->next;
        while (sa != NULL) {
            type_to_str(buf1, sizeof(buf1), &sa->type, NULL);
            pstrcat(buf, buf_size, buf1);
            sa = sa->next;
            if (sa)
                pstrcat(buf, buf_size, ", ");
        }
        pstrcat(buf, buf_size, ")");
        goto no_var;
    case VT_PTR:
        s = type->ref;
        if (t & VT_ARRAY) {
            snprintf(buf1, sizeof(buf1), "%s[%d]", varstr ? varstr : "", s->c);
            type_to_str(buf, buf_size, &s->type, buf1);
            goto no_var;
        }
        pstrcpy(buf1, sizeof(buf1), "*");
        if (t & VT_CONSTANT)
            pstrcat(buf1, buf_size, "const ");
        if (t & VT_VOLATILE)
            pstrcat(buf1, buf_size, "volatile ");
        if (varstr)
            pstrcat(buf1, sizeof(buf1), varstr);
        type_to_str(buf, buf_size, &s->type, buf1);
        goto no_var;
    }
    if (varstr) {
        pstrcat(buf, buf_size, " ");
        pstrcat(buf, buf_size, varstr);
    }
no_var: ;
}

int pointed_size(CType *type)
{
    int align;
    return type_size(pointed_type(type), &align);
}