x86-64 codegen: avoid allocating VLA of size 0

[tinycc.git] / tccgen.c

/*
 *  TCC - Tiny C Compiler
 * 
 *  Copyright (c) 2001-2004 Fabrice Bellard
 *
 * 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 "tcc.h"
/********************************************************/
/* global variables */

/* loc : local variable index
   ind : output code index
   rsym: return symbol
   anon_sym: anonymous symbol index
*/
ST_DATA int rsym, anon_sym, ind, loc;

ST_DATA Sym *sym_free_first;
ST_DATA void **sym_pools;
ST_DATA int nb_sym_pools;

ST_DATA Sym *global_stack;
ST_DATA Sym *local_stack;
ST_DATA Sym *define_stack;
ST_DATA Sym *global_label_stack;
ST_DATA Sym *local_label_stack;

static Sym *all_cleanups, *current_cleanups, *pending_gotos;
static int ncleanups;

static int local_scope;
static int in_sizeof;
static int section_sym;

ST_DATA int vlas_in_scope; /* number of VLAs that are currently in scope */
ST_DATA int vla_sp_root_loc; /* vla_sp_loc for SP before any VLAs were pushed */
ST_DATA int vla_sp_loc; /* Pointer to variable holding location to store stack pointer on the stack when modifying stack pointer */

ST_DATA SValue __vstack[1+VSTACK_SIZE], *vtop, *pvtop;

ST_DATA int const_wanted; /* true if constant wanted */
ST_DATA int nocode_wanted; /* no code generation wanted */
#define NODATA_WANTED (nocode_wanted > 0) /* no static data output wanted either */
#define STATIC_DATA_WANTED (nocode_wanted & 0xC0000000) /* only static data output */
ST_DATA int global_expr;  /* true if compound literals must be allocated globally (used during initializers parsing */
ST_DATA CType func_vt; /* current function return type (used by return instruction) */
ST_DATA int func_var; /* true if current function is variadic (used by return instruction) */
ST_DATA int func_vc;
ST_DATA int last_line_num, last_ind, func_ind; /* debug last line number and pc */
ST_DATA const char *funcname;
ST_DATA int g_debug;

ST_DATA CType char_pointer_type, func_old_type, int_type, size_type, ptrdiff_type;

ST_DATA struct switch_t {
    struct case_t {
        int64_t v1, v2;
        int sym;
    } **p; int n; /* list of case ranges */
    int def_sym; /* default symbol */
} *cur_switch; /* current switch */

#define MAX_TEMP_LOCAL_VARIABLE_NUMBER 0x4
/*list of temporary local variables on the stack in current function. */
ST_DATA struct temp_local_variable {
        int location; //offset on stack. Svalue.c.i
        short size;
        short align;
} arr_temp_local_vars[MAX_TEMP_LOCAL_VARIABLE_NUMBER];
short nb_temp_local_vars;

/* ------------------------------------------------------------------------- */

static void gen_cast(CType *type);
static void gen_cast_s(int t);
static inline CType *pointed_type(CType *type);
static int is_compatible_types(CType *type1, CType *type2);
static int parse_btype(CType *type, AttributeDef *ad);
static CType *type_decl(CType *type, AttributeDef *ad, int *v, int td);
static void parse_expr_type(CType *type);
static void init_putv(CType *type, Section *sec, unsigned long c);
static void decl_initializer(CType *type, Section *sec, unsigned long c, int flags);
static void block(int *bsym, Sym *bcl, int *csym, Sym *ccl, int is_expr);
static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r, int has_init, int v, int scope);
static void decl(int l);
static int decl0(int l, int is_for_loop_init, Sym *);
static void expr_eq(void);
static void vla_runtime_type_size(CType *type, int *a);
static void vla_sp_restore(void);
static void vla_sp_restore_root(void);
static int is_compatible_unqualified_types(CType *type1, CType *type2);
static inline int64_t expr_const64(void);
static void vpush64(int ty, unsigned long long v);
static void vpush(CType *type);
static int gvtst(int inv, int t);
static void gen_inline_functions(TCCState *s);
static void skip_or_save_block(TokenString **str);
static void gv_dup(void);
static int get_temp_local_var(int size,int align);
static void clear_temp_local_var_list();


static void reset_local_scope(void)
{
    if (current_cleanups)
      tcc_error("ICE current_cleanups");
    sym_pop(&all_cleanups, NULL, 0);
    local_scope = 0;
}

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

/* we use our own 'finite' function to avoid potential problems with
   non standard math libs */
/* XXX: endianness dependent */
ST_FUNC int ieee_finite(double d)
{
    int p[4];
    memcpy(p, &d, sizeof(double));
    return ((unsigned)((p[1] | 0x800fffff) + 1)) >> 31;
}

/* compiling intel long double natively */
#if (defined __i386__ || defined __x86_64__) \
    && (defined TCC_TARGET_I386 || defined TCC_TARGET_X86_64)
# define TCC_IS_NATIVE_387
#endif

ST_FUNC void test_lvalue(void)
{
    if (!(vtop->r & VT_LVAL))
        expect("lvalue");
}

ST_FUNC void check_vstack(void)
{
    if (pvtop != vtop)
        tcc_error("internal compiler error: vstack leak (%d)", vtop - pvtop);
}

/* ------------------------------------------------------------------------- */
/* vstack debugging aid */

#if 0
void pv (const char *lbl, int a, int b)
{
    int i;
    for (i = a; i < a + b; ++i) {
        SValue *p = &vtop[-i];
        printf("%s vtop[-%d] : type.t:%04x  r:%04x  r2:%04x  c.i:%d\n",
            lbl, i, p->type.t, p->r, p->r2, (int)p->c.i);
    }
}
#endif

/* ------------------------------------------------------------------------- */
/* start of translation unit info */
ST_FUNC void tcc_debug_start(TCCState *s1)
{
    if (s1->do_debug) {
        char buf[512];

        /* file info: full path + filename */
        section_sym = put_elf_sym(symtab_section, 0, 0,
                                  ELFW(ST_INFO)(STB_LOCAL, STT_SECTION), 0,
                                  text_section->sh_num, NULL);
        getcwd(buf, sizeof(buf));
#ifdef _WIN32
        normalize_slashes(buf);
#endif
        pstrcat(buf, sizeof(buf), "/");
        put_stabs_r(buf, N_SO, 0, 0,
                    text_section->data_offset, text_section, section_sym);
        put_stabs_r(file->filename, N_SO, 0, 0,
                    text_section->data_offset, text_section, section_sym);
        last_ind = 0;
        last_line_num = 0;
    }

    /* an elf symbol of type STT_FILE must be put so that STB_LOCAL
       symbols can be safely used */
    put_elf_sym(symtab_section, 0, 0,
                ELFW(ST_INFO)(STB_LOCAL, STT_FILE), 0,
                SHN_ABS, file->filename);
}

/* put end of translation unit info */
ST_FUNC void tcc_debug_end(TCCState *s1)
{
    if (!s1->do_debug)
        return;
    put_stabs_r(NULL, N_SO, 0, 0,
        text_section->data_offset, text_section, section_sym);

}

/* generate line number info */
ST_FUNC void tcc_debug_line(TCCState *s1)
{
    if (!s1->do_debug)
        return;
    if ((last_line_num != file->line_num || last_ind != ind)) {
        put_stabn(N_SLINE, 0, file->line_num, ind - func_ind);
        last_ind = ind;
        last_line_num = file->line_num;
    }
}

/* put function symbol */
ST_FUNC void tcc_debug_funcstart(TCCState *s1, Sym *sym)
{
    char buf[512];

    if (!s1->do_debug)
        return;

    /* stabs info */
    /* XXX: we put here a dummy type */
    snprintf(buf, sizeof(buf), "%s:%c1",
             funcname, sym->type.t & VT_STATIC ? 'f' : 'F');
    put_stabs_r(buf, N_FUN, 0, file->line_num, 0,
                cur_text_section, sym->c);
    /* //gr gdb wants a line at the function */
    put_stabn(N_SLINE, 0, file->line_num, 0);

    last_ind = 0;
    last_line_num = 0;
}

/* put function size */
ST_FUNC void tcc_debug_funcend(TCCState *s1, int size)
{
    if (!s1->do_debug)
        return;
    put_stabn(N_FUN, 0, 0, size);
}

/* ------------------------------------------------------------------------- */
ST_FUNC int tccgen_compile(TCCState *s1)
{
    cur_text_section = NULL;
    funcname = "";
    anon_sym = SYM_FIRST_ANOM;
    section_sym = 0;
    const_wanted = 0;
    nocode_wanted = 0x80000000;

    /* define some often used types */
    int_type.t = VT_INT;
    char_pointer_type.t = VT_BYTE;
    mk_pointer(&char_pointer_type);
#if PTR_SIZE == 4
    size_type.t = VT_INT | VT_UNSIGNED;
    ptrdiff_type.t = VT_INT;
#elif LONG_SIZE == 4
    size_type.t = VT_LLONG | VT_UNSIGNED;
    ptrdiff_type.t = VT_LLONG;
#else
    size_type.t = VT_LONG | VT_LLONG | VT_UNSIGNED;
    ptrdiff_type.t = VT_LONG | VT_LLONG;
#endif
    func_old_type.t = VT_FUNC;
    func_old_type.ref = sym_push(SYM_FIELD, &int_type, 0, 0);
    func_old_type.ref->f.func_call = FUNC_CDECL;
    func_old_type.ref->f.func_type = FUNC_OLD;

    tcc_debug_start(s1);

#ifdef TCC_TARGET_ARM
    arm_init(s1);
#endif

#ifdef INC_DEBUG
    printf("%s: **** new file\n", file->filename);
#endif

    parse_flags = PARSE_FLAG_PREPROCESS | PARSE_FLAG_TOK_NUM | PARSE_FLAG_TOK_STR;
    next();
    decl(VT_CONST);
    gen_inline_functions(s1);
    check_vstack();
    /* end of translation unit info */
    tcc_debug_end(s1);
    return 0;
}

/* ------------------------------------------------------------------------- */
ST_FUNC ElfSym *elfsym(Sym *s)
{
  if (!s || !s->c)
    return NULL;
  return &((ElfSym *)symtab_section->data)[s->c];
}

/* apply storage attributes to Elf symbol */
ST_FUNC void update_storage(Sym *sym)
{
    ElfSym *esym;
    int sym_bind, old_sym_bind;

    esym = elfsym(sym);
    if (!esym)
        return;

    if (sym->a.visibility)
        esym->st_other = (esym->st_other & ~ELFW(ST_VISIBILITY)(-1))
            | sym->a.visibility;

    if ((sym->type.t & VT_STATIC)
        || (sym->type.t & (VT_EXTERN | VT_INLINE)) == VT_INLINE)
        sym_bind = STB_LOCAL;
    else if (sym->a.weak)
        sym_bind = STB_WEAK;
    else
        sym_bind = STB_GLOBAL;
    old_sym_bind = ELFW(ST_BIND)(esym->st_info);
    if (sym_bind != old_sym_bind) {
        esym->st_info = ELFW(ST_INFO)(sym_bind, ELFW(ST_TYPE)(esym->st_info));
    }

#ifdef TCC_TARGET_PE
    if (sym->a.dllimport)
        esym->st_other |= ST_PE_IMPORT;
    if (sym->a.dllexport)
        esym->st_other |= ST_PE_EXPORT;
#endif

#if 0
    printf("storage %s: bind=%c vis=%d exp=%d imp=%d\n",
        get_tok_str(sym->v, NULL),
        sym_bind == STB_WEAK ? 'w' : sym_bind == STB_LOCAL ? 'l' : 'g',
        sym->a.visibility,
        sym->a.dllexport,
        sym->a.dllimport
        );
#endif
}

/* ------------------------------------------------------------------------- */
/* update sym->c so that it points to an external symbol in section
   'section' with value 'value' */

ST_FUNC void put_extern_sym2(Sym *sym, int sh_num,
                            addr_t value, unsigned long size,
                            int can_add_underscore)
{
    int sym_type, sym_bind, info, other, t;
    ElfSym *esym;
    const char *name;
    char buf1[256];
#ifdef CONFIG_TCC_BCHECK
    char buf[32];
#endif

    if (!sym->c) {
        name = get_tok_str(sym->v, NULL);
#ifdef CONFIG_TCC_BCHECK
        if (tcc_state->do_bounds_check) {
            /* XXX: avoid doing that for statics ? */
            /* if bound checking is activated, we change some function
               names by adding the "__bound" prefix */
            switch(sym->v) {
#ifdef TCC_TARGET_PE
            /* XXX: we rely only on malloc hooks */
            case TOK_malloc:
            case TOK_free:
            case TOK_realloc:
            case TOK_memalign:
            case TOK_calloc:
#endif
            case TOK_memcpy:
            case TOK_memmove:
            case TOK_memset:
            case TOK_strlen:
            case TOK_strcpy:
            case TOK_alloca:
                strcpy(buf, "__bound_");
                strcat(buf, name);
                name = buf;
                break;
            }
        }
#endif
        t = sym->type.t;
        if ((t & VT_BTYPE) == VT_FUNC) {
            sym_type = STT_FUNC;
        } else if ((t & VT_BTYPE) == VT_VOID) {
            sym_type = STT_NOTYPE;
        } else {
            sym_type = STT_OBJECT;
        }
        if ((t & VT_STATIC) || (t & (VT_EXTERN | VT_INLINE)) == VT_INLINE)
            sym_bind = STB_LOCAL;
        else
            sym_bind = STB_GLOBAL;
        other = 0;
#ifdef TCC_TARGET_PE
        if (sym_type == STT_FUNC && sym->type.ref) {
            Sym *ref = sym->type.ref;
            if (ref->a.nodecorate) {
                can_add_underscore = 0;
            }
            if (ref->f.func_call == FUNC_STDCALL && can_add_underscore) {
                sprintf(buf1, "_%s@%d", name, ref->f.func_args * PTR_SIZE);
                name = buf1;
                other |= ST_PE_STDCALL;
                can_add_underscore = 0;
            }
        }
#endif
        if (tcc_state->leading_underscore && can_add_underscore) {
            buf1[0] = '_';
            pstrcpy(buf1 + 1, sizeof(buf1) - 1, name);
            name = buf1;
        }
        if (sym->asm_label)
            name = get_tok_str(sym->asm_label, NULL);
        info = ELFW(ST_INFO)(sym_bind, sym_type);
        sym->c = put_elf_sym(symtab_section, value, size, info, other, sh_num, name);
    } else {
        esym = elfsym(sym);
        esym->st_value = value;
        esym->st_size = size;
        esym->st_shndx = sh_num;
    }
    update_storage(sym);
}

ST_FUNC void put_extern_sym(Sym *sym, Section *section,
                           addr_t value, unsigned long size)
{
    int sh_num = section ? section->sh_num : SHN_UNDEF;
    put_extern_sym2(sym, sh_num, value, size, 1);
}

/* add a new relocation entry to symbol 'sym' in section 's' */
ST_FUNC void greloca(Section *s, Sym *sym, unsigned long offset, int type,
                     addr_t addend)
{
    int c = 0;

    if (nocode_wanted && s == cur_text_section)
        return;

    if (sym) {
        if (0 == sym->c)
            put_extern_sym(sym, NULL, 0, 0);
        c = sym->c;
    }

    /* now we can add ELF relocation info */
    put_elf_reloca(symtab_section, s, offset, type, c, addend);
}

#if PTR_SIZE == 4
ST_FUNC void greloc(Section *s, Sym *sym, unsigned long offset, int type)
{
    greloca(s, sym, offset, type, 0);
}
#endif

/* ------------------------------------------------------------------------- */
/* symbol allocator */
static Sym *__sym_malloc(void)
{
    Sym *sym_pool, *sym, *last_sym;
    int i;

    sym_pool = tcc_malloc(SYM_POOL_NB * sizeof(Sym));
    dynarray_add(&sym_pools, &nb_sym_pools, sym_pool);

    last_sym = sym_free_first;
    sym = sym_pool;
    for(i = 0; i < SYM_POOL_NB; i++) {
        sym->next = last_sym;
        last_sym = sym;
        sym++;
    }
    sym_free_first = last_sym;
    return last_sym;
}

static inline Sym *sym_malloc(void)
{
    Sym *sym;
#ifndef SYM_DEBUG
    sym = sym_free_first;
    if (!sym)
        sym = __sym_malloc();
    sym_free_first = sym->next;
    return sym;
#else
    sym = tcc_malloc(sizeof(Sym));
    return sym;
#endif
}

ST_INLN void sym_free(Sym *sym)
{
#ifndef SYM_DEBUG
    sym->next = sym_free_first;
    sym_free_first = sym;
#else
    tcc_free(sym);
#endif
}

/* push, without hashing */
ST_FUNC Sym *sym_push2(Sym **ps, int v, int t, int c)
{
    Sym *s;

    s = sym_malloc();
    memset(s, 0, sizeof *s);
    s->v = v;
    s->type.t = t;
    s->c = c;
    /* add in stack */
    s->prev = *ps;
    *ps = s;
    return s;
}

/* find a symbol and return its associated structure. 's' is the top
   of the symbol stack */
ST_FUNC Sym *sym_find2(Sym *s, int v)
{
    while (s) {
        if (s->v == v)
            return s;
        else if (s->v == -1)
            return NULL;
        s = s->prev;
    }
    return NULL;
}

/* structure lookup */
ST_INLN Sym *struct_find(int v)
{
    v -= TOK_IDENT;
    if ((unsigned)v >= (unsigned)(tok_ident - TOK_IDENT))
        return NULL;
    return table_ident[v]->sym_struct;
}

/* find an identifier */
ST_INLN Sym *sym_find(int v)
{
    v -= TOK_IDENT;
    if ((unsigned)v >= (unsigned)(tok_ident - TOK_IDENT))
        return NULL;
    return table_ident[v]->sym_identifier;
}

static int sym_scope(Sym *s)
{
  if (IS_ENUM_VAL (s->type.t))
    return s->type.ref->sym_scope;
  else
    return s->sym_scope;
}

/* push a given symbol on the symbol stack */
ST_FUNC Sym *sym_push(int v, CType *type, int r, int c)
{
    Sym *s, **ps;
    TokenSym *ts;

    if (local_stack)
        ps = &local_stack;
    else
        ps = &global_stack;
    s = sym_push2(ps, v, type->t, c);
    s->type.ref = type->ref;
    s->r = r;
    /* don't record fields or anonymous symbols */
    /* XXX: simplify */
    if (!(v & SYM_FIELD) && (v & ~SYM_STRUCT) < SYM_FIRST_ANOM) {
        /* record symbol in token array */
        ts = table_ident[(v & ~SYM_STRUCT) - TOK_IDENT];
        if (v & SYM_STRUCT)
            ps = &ts->sym_struct;
        else
            ps = &ts->sym_identifier;
        s->prev_tok = *ps;
        *ps = s;
        s->sym_scope = local_scope;
        if (s->prev_tok && sym_scope(s->prev_tok) == s->sym_scope)
            tcc_error("redeclaration of '%s'",
                get_tok_str(v & ~SYM_STRUCT, NULL));
    }
    return s;
}

/* push a global identifier */
ST_FUNC Sym *global_identifier_push(int v, int t, int c)
{
    Sym *s, **ps;
    s = sym_push2(&global_stack, v, t, c);
    s->r = VT_CONST | VT_SYM;
    /* don't record anonymous symbol */
    if (v < SYM_FIRST_ANOM) {
        ps = &table_ident[v - TOK_IDENT]->sym_identifier;
        /* modify the top most local identifier, so that sym_identifier will
           point to 's' when popped; happens when called from inline asm */
        while (*ps != NULL && (*ps)->sym_scope)
            ps = &(*ps)->prev_tok;
        s->prev_tok = *ps;
        *ps = s;
    }
    return s;
}

/* pop symbols until top reaches 'b'.  If KEEP is non-zero don't really
   pop them yet from the list, but do remove them from the token array.  */
ST_FUNC void sym_pop(Sym **ptop, Sym *b, int keep)
{
    Sym *s, *ss, **ps;
    TokenSym *ts;
    int v;

    s = *ptop;
    while(s != b) {
        ss = s->prev;
        v = s->v;
        /* remove symbol in token array */
        /* XXX: simplify */
        if (!(v & SYM_FIELD) && (v & ~SYM_STRUCT) < SYM_FIRST_ANOM) {
            ts = table_ident[(v & ~SYM_STRUCT) - TOK_IDENT];
            if (v & SYM_STRUCT)
                ps = &ts->sym_struct;
            else
                ps = &ts->sym_identifier;
            *ps = s->prev_tok;
        }
        if (!keep)
            sym_free(s);
        s = ss;
    }
    if (!keep)
        *ptop = b;
}

/* ------------------------------------------------------------------------- */

static void vsetc(CType *type, int r, CValue *vc)
{
    int v;

    if (vtop >= vstack + (VSTACK_SIZE - 1))
        tcc_error("memory full (vstack)");
    /* cannot let cpu flags if other instruction are generated. Also
       avoid leaving VT_JMP anywhere except on the top of the stack
       because it would complicate the code generator.

       Don't do this when nocode_wanted.  vtop might come from
       !nocode_wanted regions (see 88_codeopt.c) and transforming
       it to a register without actually generating code is wrong
       as their value might still be used for real.  All values
       we push under nocode_wanted will eventually be popped
       again, so that the VT_CMP/VT_JMP value will be in vtop
       when code is unsuppressed again.

       Same logic below in vswap(); */
    if (vtop >= vstack && !nocode_wanted) {
        v = vtop->r & VT_VALMASK;
        if (v == VT_CMP || (v & ~1) == VT_JMP)
            gv(RC_INT);
    }

    vtop++;
    vtop->type = *type;
    vtop->r = r;
    vtop->r2 = VT_CONST;
    vtop->c = *vc;
    vtop->sym = NULL;
}

ST_FUNC void vswap(void)
{
    SValue tmp;
    /* cannot vswap cpu flags. See comment at vsetc() above */
    if (vtop >= vstack && !nocode_wanted) {
        int v = vtop->r & VT_VALMASK;
        if (v == VT_CMP || (v & ~1) == VT_JMP)
            gv(RC_INT);
    }
    tmp = vtop[0];
    vtop[0] = vtop[-1];
    vtop[-1] = tmp;
}

/* pop stack value */
ST_FUNC void vpop(void)
{
    int v;
    v = vtop->r & VT_VALMASK;
#if defined(TCC_TARGET_I386) || defined(TCC_TARGET_X86_64)
    /* for x86, we need to pop the FP stack */
    if (v == TREG_ST0) {
        o(0xd8dd); /* fstp %st(0) */
    } else
#endif
    if (v == VT_JMP || v == VT_JMPI) {
        /* need to put correct jump if && or || without test */
        gsym(vtop->c.i);
    }
    vtop--;
}

/* push constant of type "type" with useless value */
ST_FUNC void vpush(CType *type)
{
    vset(type, VT_CONST, 0);
}

/* push integer constant */
ST_FUNC void vpushi(int v)
{
    CValue cval;
    cval.i = v;
    vsetc(&int_type, VT_CONST, &cval);
}

/* push a pointer sized constant */
static void vpushs(addr_t v)
{
  CValue cval;
  cval.i = v;
  vsetc(&size_type, VT_CONST, &cval);
}

/* push arbitrary 64bit constant */
ST_FUNC void vpush64(int ty, unsigned long long v)
{
    CValue cval;
    CType ctype;
    ctype.t = ty;
    ctype.ref = NULL;
    cval.i = v;
    vsetc(&ctype, VT_CONST, &cval);
}

/* push long long constant */
static inline void vpushll(long long v)
{
    vpush64(VT_LLONG, v);
}

ST_FUNC void vset(CType *type, int r, int v)
{
    CValue cval;

    cval.i = v;
    vsetc(type, r, &cval);
}

static void vseti(int r, int v)
{
    CType type;
    type.t = VT_INT;
    type.ref = NULL;
    vset(&type, r, v);
}

ST_FUNC void vpushv(SValue *v)
{
    if (vtop >= vstack + (VSTACK_SIZE - 1))
        tcc_error("memory full (vstack)");
    vtop++;
    *vtop = *v;
}

static void vdup(void)
{
    vpushv(vtop);
}

/* rotate n first stack elements to the bottom
   I1 ... In -> I2 ... In I1 [top is right]
*/
ST_FUNC void vrotb(int n)
{
    int i;
    SValue tmp;

    tmp = vtop[-n + 1];
    for(i=-n+1;i!=0;i++)
        vtop[i] = vtop[i+1];
    vtop[0] = tmp;
}

/* rotate the n elements before entry e towards the top
   I1 ... In ... -> In I1 ... I(n-1) ... [top is right]
 */
ST_FUNC void vrote(SValue *e, int n)
{
    int i;
    SValue tmp;

    tmp = *e;
    for(i = 0;i < n - 1; i++)
        e[-i] = e[-i - 1];
    e[-n + 1] = tmp;
}

/* rotate n first stack elements to the top
   I1 ... In -> In I1 ... I(n-1)  [top is right]
 */
ST_FUNC void vrott(int n)
{
    vrote(vtop, n);
}

/* push a symbol value of TYPE */
static inline void vpushsym(CType *type, Sym *sym)
{
    CValue cval;
    cval.i = 0;
    vsetc(type, VT_CONST | VT_SYM, &cval);
    vtop->sym = sym;
}

/* Return a static symbol pointing to a section */
ST_FUNC Sym *get_sym_ref(CType *type, Section *sec, unsigned long offset, unsigned long size)
{
    int v;
    Sym *sym;

    v = anon_sym++;
    sym = sym_push(v, type, VT_CONST | VT_SYM, 0);
    sym->type.t |= VT_STATIC;
    put_extern_sym(sym, sec, offset, size);
    return sym;
}

/* push a reference to a section offset by adding a dummy symbol */
static void vpush_ref(CType *type, Section *sec, unsigned long offset, unsigned long size)
{
    vpushsym(type, get_sym_ref(type, sec, offset, size));  
}

/* define a new external reference to a symbol 'v' of type 'u' */
ST_FUNC Sym *external_global_sym(int v, CType *type)
{
    Sym *s;

    s = sym_find(v);
    if (!s) {
        /* push forward reference */
        s = global_identifier_push(v, type->t | VT_EXTERN, 0);
        s->type.ref = type->ref;
    } else if (IS_ASM_SYM(s)) {
        s->type.t = type->t | (s->type.t & VT_EXTERN);
        s->type.ref = type->ref;
        update_storage(s);
    }
    return s;
}

/* Merge symbol attributes.  */
static void merge_symattr(struct SymAttr *sa, struct SymAttr *sa1)
{
    if (sa1->aligned && !sa->aligned)
      sa->aligned = sa1->aligned;
    sa->packed |= sa1->packed;
    sa->weak |= sa1->weak;
    if (sa1->visibility != STV_DEFAULT) {
        int vis = sa->visibility;
        if (vis == STV_DEFAULT
            || vis > sa1->visibility)
          vis = sa1->visibility;
        sa->visibility = vis;
    }
    sa->dllexport |= sa1->dllexport;
    sa->nodecorate |= sa1->nodecorate;
    sa->dllimport |= sa1->dllimport;
}

/* Merge function attributes.  */
static void merge_funcattr(struct FuncAttr *fa, struct FuncAttr *fa1)
{
    if (fa1->func_call && !fa->func_call)
      fa->func_call = fa1->func_call;
    if (fa1->func_type && !fa->func_type)
      fa->func_type = fa1->func_type;
    if (fa1->func_args && !fa->func_args)
      fa->func_args = fa1->func_args;
}

/* Merge attributes.  */
static void merge_attr(AttributeDef *ad, AttributeDef *ad1)
{
    merge_symattr(&ad->a, &ad1->a);
    merge_funcattr(&ad->f, &ad1->f);

    if (ad1->section)
      ad->section = ad1->section;
    if (ad1->alias_target)
      ad->alias_target = ad1->alias_target;
    if (ad1->asm_label)
      ad->asm_label = ad1->asm_label;
    if (ad1->attr_mode)
      ad->attr_mode = ad1->attr_mode;
}

/* Merge some type attributes.  */
static void patch_type(Sym *sym, CType *type)
{
    if ((!(type->t & VT_EXTERN) || IS_ENUM_VAL(sym->type.t))
        && (type->t & VT_BTYPE) != VT_FUNC) {
        if (!(sym->type.t & VT_EXTERN))
            tcc_error("redefinition of '%s'", get_tok_str(sym->v, NULL));
        sym->type.t &= ~VT_EXTERN;
    }

    if (IS_ASM_SYM(sym)) {
        /* stay static if both are static */
        sym->type.t = type->t & (sym->type.t | ~VT_STATIC);
        sym->type.ref = type->ref;
    }

    if (!is_compatible_types(&sym->type, type)) {
        tcc_error("incompatible types for redefinition of '%s'",
                  get_tok_str(sym->v, NULL));

    } else if ((sym->type.t & VT_BTYPE) == VT_FUNC) {
        int static_proto = sym->type.t & VT_STATIC;
        /* warn if static follows non-static function declaration */
        if ((type->t & VT_STATIC) && !static_proto
            /* XXX this test for inline shouldn't be here.  Until we
               implement gnu-inline mode again it silences a warning for
               mingw caused by our workarounds.  */
            && !((type->t | sym->type.t) & VT_INLINE))
            tcc_warning("static storage ignored for redefinition of '%s'",
                get_tok_str(sym->v, NULL));

        /* Force external definition if unequal inline specifier
           or an explicit extern one.  */
        if ((sym->type.t | type->t) & VT_STATIC) {
            type->t |= sym->type.t & VT_INLINE;
            sym->type.t |= type->t & VT_INLINE;
        } else if (((type->t & VT_INLINE) != (sym->type.t & VT_INLINE)
             || (type->t | sym->type.t) & VT_EXTERN)
            && !static_proto) {
            type->t &= ~VT_INLINE;
            sym->type.t &= ~VT_INLINE;
        }
        if (0 == (type->t & VT_EXTERN)) {
            /* put complete type, use static from prototype, but don't
               overwrite type.ref, it might contain parameter names */
            sym->type.t = (type->t & ~VT_STATIC) | static_proto;
        }
    } else {
        if ((sym->type.t & VT_ARRAY) && type->ref->c >= 0) {
            /* set array size if it was omitted in extern declaration */
            if (sym->type.ref->c < 0)
                sym->type.ref->c = type->ref->c;
            else if (sym->type.ref->c != type->ref->c)
                tcc_error("conflicting type for '%s'", get_tok_str(sym->v, NULL));
        }
        if ((type->t ^ sym->type.t) & VT_STATIC)
            tcc_warning("storage mismatch for redefinition of '%s'",
                get_tok_str(sym->v, NULL));
    }
}


/* Merge some storage attributes.  */
static void patch_storage(Sym *sym, AttributeDef *ad, CType *type)
{
    if (type)
        patch_type(sym, type);

#ifdef TCC_TARGET_PE
    if (sym->a.dllimport != ad->a.dllimport)
        tcc_error("incompatible dll linkage for redefinition of '%s'",
            get_tok_str(sym->v, NULL));
#endif
    merge_symattr(&sym->a, &ad->a);
    if (ad->asm_label)
        sym->asm_label = ad->asm_label;
    update_storage(sym);
}

/* define a new external reference to a symbol 'v' */
static Sym *external_sym(int v, CType *type, int r, AttributeDef *ad)
{
    Sym *s;
    s = sym_find(v);
    if (!s || (!IS_ASM_SYM(s) && !(s->type.t & VT_EXTERN)
               && (!(type->t & VT_EXTERN) || s->sym_scope)
               && (s->type.t & VT_BTYPE) != VT_FUNC)) {
        if (s && !is_compatible_types(&s->type, type))
            tcc_error("conflicting types for '%s'", get_tok_str(s->v, NULL));
        /* push forward reference */
        s = sym_push(v, type, r | VT_CONST | VT_SYM, 0);
        s->a = ad->a;
        s->asm_label = ad->asm_label;
        s->sym_scope = 0;
    } else {
        if (s->type.ref == func_old_type.ref) {
            s->type.ref = type->ref;
            s->r = r | VT_CONST | VT_SYM;
            s->type.t |= VT_EXTERN;
        }
        patch_storage(s, ad, type);
    }
    return s;
}

/* push a reference to global symbol v */
ST_FUNC void vpush_global_sym(CType *type, int v)
{
    vpushsym(type, external_global_sym(v, type));
}

/* save registers up to (vtop - n) stack entry */
ST_FUNC void save_regs(int n)
{
    SValue *p, *p1;
    for(p = vstack, p1 = vtop - n; p <= p1; p++)
        save_reg(p->r);
}

/* save r to the memory stack, and mark it as being free */
ST_FUNC void save_reg(int r)
{
    save_reg_upstack(r, 0);
}

/* save r to the memory stack, and mark it as being free,
   if seen up to (vtop - n) stack entry */
ST_FUNC void save_reg_upstack(int r, int n)
{
    int l, saved, size, align;
    SValue *p, *p1, sv;
    CType *type;

    if ((r &= VT_VALMASK) >= VT_CONST)
        return;
    if (nocode_wanted)
        return;

    /* modify all stack values */
    saved = 0;
    l = 0;
    for(p = vstack, p1 = vtop - n; p <= p1; p++) {
        if ((p->r & VT_VALMASK) == r ||
            ((p->type.t & VT_BTYPE) == VT_LLONG && (p->r2 & VT_VALMASK) == r)) {
            /* must save value on stack if not already done */
            if (!saved) {
                /* NOTE: must reload 'r' because r might be equal to r2 */
                r = p->r & VT_VALMASK;
                /* store register in the stack */
                type = &p->type;
                if ((p->r & VT_LVAL) ||
                    (!is_float(type->t) && (type->t & VT_BTYPE) != VT_LLONG))
#if PTR_SIZE == 8
                    type = &char_pointer_type;
#else
                    type = &int_type;
#endif
                size = type_size(type, &align);
                                l=get_temp_local_var(size,align);
                sv.type.t = type->t;
                sv.r = VT_LOCAL | VT_LVAL;
                sv.c.i = l;
                store(r, &sv);
#if defined(TCC_TARGET_I386) || defined(TCC_TARGET_X86_64)
                /* x86 specific: need to pop fp register ST0 if saved */
                if (r == TREG_ST0) {
                    o(0xd8dd); /* fstp %st(0) */
                }
#endif
#if PTR_SIZE == 4
                /* special long long case */
                if ((type->t & VT_BTYPE) == VT_LLONG) {
                    sv.c.i += 4;
                    store(p->r2, &sv);
                }
#endif
                saved = 1;
            }
            /* mark that stack entry as being saved on the stack */
            if (p->r & VT_LVAL) {
                /* also clear the bounded flag because the
                   relocation address of the function was stored in
                   p->c.i */
                p->r = (p->r & ~(VT_VALMASK | VT_BOUNDED)) | VT_LLOCAL;
            } else {
                p->r = lvalue_type(p->type.t) | VT_LOCAL;
            }
            p->r2 = VT_CONST;
            p->c.i = l;
        }
    }
}

#ifdef TCC_TARGET_ARM
/* find a register of class 'rc2' with at most one reference on stack.
 * If none, call get_reg(rc) */
ST_FUNC int get_reg_ex(int rc, int rc2)
{
    int r;
    SValue *p;
    
    for(r=0;r<NB_REGS;r++) {
        if (reg_classes[r] & rc2) {
            int n;
            n=0;
            for(p = vstack; p <= vtop; p++) {
                if ((p->r & VT_VALMASK) == r ||
                    (p->r2 & VT_VALMASK) == r)
                    n++;
            }
            if (n <= 1)
                return r;
        }
    }
    return get_reg(rc);
}
#endif

/* find a free register of class 'rc'. If none, save one register */
ST_FUNC int get_reg(int rc)
{
    int r;
    SValue *p;

    /* find a free register */
    for(r=0;r<NB_REGS;r++) {
        if (reg_classes[r] & rc) {
            if (nocode_wanted)
                return r;
            for(p=vstack;p<=vtop;p++) {
                if ((p->r & VT_VALMASK) == r ||
                    (p->r2 & VT_VALMASK) == r)
                    goto notfound;
            }
            return r;
        }
    notfound: ;
    }
    
    /* no register left : free the first one on the stack (VERY
       IMPORTANT to start from the bottom to ensure that we don't
       spill registers used in gen_opi()) */
    for(p=vstack;p<=vtop;p++) {
        /* look at second register (if long long) */
        r = p->r2 & VT_VALMASK;
        if (r < VT_CONST && (reg_classes[r] & rc))
            goto save_found;
        r = p->r & VT_VALMASK;
        if (r < VT_CONST && (reg_classes[r] & rc)) {
        save_found:
            save_reg(r);
            return r;
        }
    }
    /* Should never comes here */
    return -1;
}

/* find a free temporary local variable (return the offset on stack) match the size and align. If none, add new temporary stack variable*/
static int get_temp_local_var(int size,int align){
        int i;
        struct temp_local_variable *temp_var;
        int found_var;
        SValue *p;
        int r;
        char free;
        char found;
        found=0;
        for(i=0;i<nb_temp_local_vars;i++){
                temp_var=&arr_temp_local_vars[i];
                if(temp_var->size<size||align!=temp_var->align){
                        continue;
                }
                /*check if temp_var is free*/
                free=1;
                for(p=vstack;p<=vtop;p++) {
                        r=p->r&VT_VALMASK;
                        if(r==VT_LOCAL||r==VT_LLOCAL){
                                if(p->c.i==temp_var->location){
                                        free=0;
                                        break;
                                }
                        }
                }
                if(free){
                        found_var=temp_var->location;
                        found=1;
                        break;
                }
        }
        if(!found){
                loc = (loc - size) & -align;
                if(nb_temp_local_vars<MAX_TEMP_LOCAL_VARIABLE_NUMBER){
                        temp_var=&arr_temp_local_vars[i];
                        temp_var->location=loc;
                        temp_var->size=size;
                        temp_var->align=align;
                        nb_temp_local_vars++;
                }
                found_var=loc;
        }
        return found_var;
}

static void clear_temp_local_var_list(){
        nb_temp_local_vars=0;
}

/* move register 's' (of type 't') to 'r', and flush previous value of r to memory
   if needed */
static void move_reg(int r, int s, int t)
{
    SValue sv;

    if (r != s) {
        save_reg(r);
        sv.type.t = t;
        sv.type.ref = NULL;
        sv.r = s;
        sv.c.i = 0;
        load(r, &sv);
    }
}

/* get address of vtop (vtop MUST BE an lvalue) */
ST_FUNC void gaddrof(void)
{
    vtop->r &= ~VT_LVAL;
    /* tricky: if saved lvalue, then we can go back to lvalue */
    if ((vtop->r & VT_VALMASK) == VT_LLOCAL)
        vtop->r = (vtop->r & ~(VT_VALMASK | VT_LVAL_TYPE)) | VT_LOCAL | VT_LVAL;


}

#ifdef CONFIG_TCC_BCHECK
/* generate lvalue bound code */
static void gbound(void)
{
    int lval_type;
    CType type1;

    vtop->r &= ~VT_MUSTBOUND;
    /* if lvalue, then use checking code before dereferencing */
    if (vtop->r & VT_LVAL) {
        /* if not VT_BOUNDED value, then make one */
        if (!(vtop->r & VT_BOUNDED)) {
            lval_type = vtop->r & (VT_LVAL_TYPE | VT_LVAL);
            /* must save type because we must set it to int to get pointer */
            type1 = vtop->type;
            vtop->type.t = VT_PTR;
            gaddrof();
            vpushi(0);
            gen_bounded_ptr_add();
            vtop->r |= lval_type;
            vtop->type = type1;
        }
        /* then check for dereferencing */
        gen_bounded_ptr_deref();
    }
}
#endif

static void incr_bf_adr(int o)
{
    vtop->type = char_pointer_type;
    gaddrof();
    vpushi(o);
    gen_op('+');
    vtop->type.t = (vtop->type.t & ~(VT_BTYPE|VT_DEFSIGN))
        | (VT_BYTE|VT_UNSIGNED);
    vtop->r = (vtop->r & ~VT_LVAL_TYPE)
        | (VT_LVAL_BYTE|VT_LVAL_UNSIGNED|VT_LVAL);
}

/* single-byte load mode for packed or otherwise unaligned bitfields */
static void load_packed_bf(CType *type, int bit_pos, int bit_size)
{
    int n, o, bits;
    save_reg_upstack(vtop->r, 1);
    vpush64(type->t & VT_BTYPE, 0); // B X
    bits = 0, o = bit_pos >> 3, bit_pos &= 7;
    do {
        vswap(); // X B
        incr_bf_adr(o);
        vdup(); // X B B
        n = 8 - bit_pos;
        if (n > bit_size)
            n = bit_size;
        if (bit_pos)
            vpushi(bit_pos), gen_op(TOK_SHR), bit_pos = 0; // X B Y
        if (n < 8)
            vpushi((1 << n) - 1), gen_op('&');
        gen_cast(type);
        if (bits)
            vpushi(bits), gen_op(TOK_SHL);
        vrotb(3); // B Y X
        gen_op('|'); // B X
        bits += n, bit_size -= n, o = 1;
    } while (bit_size);
    vswap(), vpop();
    if (!(type->t & VT_UNSIGNED)) {
        n = ((type->t & VT_BTYPE) == VT_LLONG ? 64 : 32) - bits;
        vpushi(n), gen_op(TOK_SHL);
        vpushi(n), gen_op(TOK_SAR);
    }
}

/* single-byte store mode for packed or otherwise unaligned bitfields */
static void store_packed_bf(int bit_pos, int bit_size)
{
    int bits, n, o, m, c;

    c = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    vswap(); // X B
    save_reg_upstack(vtop->r, 1);
    bits = 0, o = bit_pos >> 3, bit_pos &= 7;
    do {
        incr_bf_adr(o); // X B
        vswap(); //B X
        c ? vdup() : gv_dup(); // B V X
        vrott(3); // X B V
        if (bits)
            vpushi(bits), gen_op(TOK_SHR);
        if (bit_pos)
            vpushi(bit_pos), gen_op(TOK_SHL);
        n = 8 - bit_pos;
        if (n > bit_size)
            n = bit_size;
        if (n < 8) {
            m = ((1 << n) - 1) << bit_pos;
            vpushi(m), gen_op('&'); // X B V1
            vpushv(vtop-1); // X B V1 B
            vpushi(m & 0x80 ? ~m & 0x7f : ~m);
            gen_op('&'); // X B V1 B1
            gen_op('|'); // X B V2
        }
        vdup(), vtop[-1] = vtop[-2]; // X B B V2
        vstore(), vpop(); // X B
        bits += n, bit_size -= n, bit_pos = 0, o = 1;
    } while (bit_size);
    vpop(), vpop();
}

static int adjust_bf(SValue *sv, int bit_pos, int bit_size)
{
    int t;
    if (0 == sv->type.ref)
        return 0;
    t = sv->type.ref->auxtype;
    if (t != -1 && t != VT_STRUCT) {
        sv->type.t = (sv->type.t & ~VT_BTYPE) | t;
        sv->r = (sv->r & ~VT_LVAL_TYPE) | lvalue_type(sv->type.t);
    }
    return t;
}

/* store vtop a register belonging to class 'rc'. lvalues are
   converted to values. Cannot be used if cannot be converted to
   register value (such as structures). */
ST_FUNC int gv(int rc)
{
    int r, bit_pos, bit_size, size, align, rc2;

    /* NOTE: get_reg can modify vstack[] */
    if (vtop->type.t & VT_BITFIELD) {
        CType type;

        bit_pos = BIT_POS(vtop->type.t);
        bit_size = BIT_SIZE(vtop->type.t);
        /* remove bit field info to avoid loops */
        vtop->type.t &= ~VT_STRUCT_MASK;

        type.ref = NULL;
        type.t = vtop->type.t & VT_UNSIGNED;
        if ((vtop->type.t & VT_BTYPE) == VT_BOOL)
            type.t |= VT_UNSIGNED;

        r = adjust_bf(vtop, bit_pos, bit_size);

        if ((vtop->type.t & VT_BTYPE) == VT_LLONG)
            type.t |= VT_LLONG;
        else
            type.t |= VT_INT;

        if (r == VT_STRUCT) {
            load_packed_bf(&type, bit_pos, bit_size);
        } else {
            int bits = (type.t & VT_BTYPE) == VT_LLONG ? 64 : 32;
            /* cast to int to propagate signedness in following ops */
            gen_cast(&type);
            /* generate shifts */
            vpushi(bits - (bit_pos + bit_size));
            gen_op(TOK_SHL);
            vpushi(bits - bit_size);
            /* NOTE: transformed to SHR if unsigned */
            gen_op(TOK_SAR);
        }
        r = gv(rc);
    } else {
        if (is_float(vtop->type.t) && 
            (vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) {
            unsigned long offset;
            /* CPUs usually cannot use float constants, so we store them
               generically in data segment */
            size = type_size(&vtop->type, &align);
            if (NODATA_WANTED)
                size = 0, align = 1;
            offset = section_add(data_section, size, align);
            vpush_ref(&vtop->type, data_section, offset, size);
            vswap();
            init_putv(&vtop->type, data_section, offset);
            vtop->r |= VT_LVAL;
        }
#ifdef CONFIG_TCC_BCHECK
        if (vtop->r & VT_MUSTBOUND) 
            gbound();
#endif

        r = vtop->r & VT_VALMASK;
        rc2 = (rc & RC_FLOAT) ? RC_FLOAT : RC_INT;
#ifndef TCC_TARGET_ARM64
        if (rc == RC_IRET)
            rc2 = RC_LRET;
#ifdef TCC_TARGET_X86_64
        else if (rc == RC_FRET)
            rc2 = RC_QRET;
#endif
#endif
        /* need to reload if:
           - constant
           - lvalue (need to dereference pointer)
           - already a register, but not in the right class */
        if (r >= VT_CONST
         || (vtop->r & VT_LVAL)
         || !(reg_classes[r] & rc)
#if PTR_SIZE == 8
         || ((vtop->type.t & VT_BTYPE) == VT_QLONG && !(reg_classes[vtop->r2] & rc2))
         || ((vtop->type.t & VT_BTYPE) == VT_QFLOAT && !(reg_classes[vtop->r2] & rc2))
#else
         || ((vtop->type.t & VT_BTYPE) == VT_LLONG && !(reg_classes[vtop->r2] & rc2))
#endif
            )
        {
            r = get_reg(rc);
#if PTR_SIZE == 8
            if (((vtop->type.t & VT_BTYPE) == VT_QLONG) || ((vtop->type.t & VT_BTYPE) == VT_QFLOAT)) {
                int addr_type = VT_LLONG, load_size = 8, load_type = ((vtop->type.t & VT_BTYPE) == VT_QLONG) ? VT_LLONG : VT_DOUBLE;
#else
            if ((vtop->type.t & VT_BTYPE) == VT_LLONG) {
                int addr_type = VT_INT, load_size = 4, load_type = VT_INT;
                unsigned long long ll;
#endif
                int r2, original_type;
                original_type = vtop->type.t;
                /* two register type load : expand to two words
                   temporarily */
#if PTR_SIZE == 4
                if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) {
                    /* load constant */
                    ll = vtop->c.i;
                    vtop->c.i = ll; /* first word */
                    load(r, vtop);
                    vtop->r = r; /* save register value */
                    vpushi(ll >> 32); /* second word */
                } else
#endif
                if (vtop->r & VT_LVAL) {
                    /* We do not want to modifier the long long
                       pointer here, so the safest (and less
                       efficient) is to save all the other registers
                       in the stack. XXX: totally inefficient. */
               #if 0
                    save_regs(1);
               #else
                    /* lvalue_save: save only if used further down the stack */
                    save_reg_upstack(vtop->r, 1);
               #endif
                    /* load from memory */
                    vtop->type.t = load_type;
                    load(r, vtop);
                    vdup();
                    vtop[-1].r = r; /* save register value */
                    /* increment pointer to get second word */
                    vtop->type.t = addr_type;
                    gaddrof();
                    vpushi(load_size);
                    gen_op('+');
                    vtop->r |= VT_LVAL;
                    vtop->type.t = load_type;
                } else {
                    /* move registers */
                    load(r, vtop);
                    vdup();
                    vtop[-1].r = r; /* save register value */
                    vtop->r = vtop[-1].r2;
                }
                /* Allocate second register. Here we rely on the fact that
                   get_reg() tries first to free r2 of an SValue. */
                r2 = get_reg(rc2);
                load(r2, vtop);
                vpop();
                /* write second register */
                vtop->r2 = r2;
                vtop->type.t = original_type;
            } else if ((vtop->r & VT_LVAL) && !is_float(vtop->type.t)) {
                int t1, t;
                /* lvalue of scalar type : need to use lvalue type
                   because of possible cast */
                t = vtop->type.t;
                t1 = t;
                /* compute memory access type */
                if (vtop->r & VT_LVAL_BYTE)
                    t = VT_BYTE;
                else if (vtop->r & VT_LVAL_SHORT)
                    t = VT_SHORT;
                if (vtop->r & VT_LVAL_UNSIGNED)
                    t |= VT_UNSIGNED;
                vtop->type.t = t;
                load(r, vtop);
                /* restore wanted type */
                vtop->type.t = t1;
            } else {
                /* one register type load */
                load(r, vtop);
            }
        }
        vtop->r = r;
#ifdef TCC_TARGET_C67
        /* uses register pairs for doubles */
        if ((vtop->type.t & VT_BTYPE) == VT_DOUBLE) 
            vtop->r2 = r+1;
#endif
    }
    return r;
}

/* generate vtop[-1] and vtop[0] in resp. classes rc1 and rc2 */
ST_FUNC void gv2(int rc1, int rc2)
{
    int v;

    /* generate more generic register first. But VT_JMP or VT_CMP
       values must be generated first in all cases to avoid possible
       reload errors */
    v = vtop[0].r & VT_VALMASK;
    if (v != VT_CMP && (v & ~1) != VT_JMP && rc1 <= rc2) {
        vswap();
        gv(rc1);
        vswap();
        gv(rc2);
        /* test if reload is needed for first register */
        if ((vtop[-1].r & VT_VALMASK) >= VT_CONST) {
            vswap();
            gv(rc1);
            vswap();
        }
    } else {
        gv(rc2);
        vswap();
        gv(rc1);
        vswap();
        /* test if reload is needed for first register */
        if ((vtop[0].r & VT_VALMASK) >= VT_CONST) {
            gv(rc2);
        }
    }
}

#ifndef TCC_TARGET_ARM64
/* wrapper around RC_FRET to return a register by type */
static int rc_fret(int t)
{
#ifdef TCC_TARGET_X86_64
    if (t == VT_LDOUBLE) {
        return RC_ST0;
    }
#endif
    return RC_FRET;
}
#endif

/* wrapper around REG_FRET to return a register by type */
static int reg_fret(int t)
{
#ifdef TCC_TARGET_X86_64
    if (t == VT_LDOUBLE) {
        return TREG_ST0;
    }
#endif
    return REG_FRET;
}

#if PTR_SIZE == 4
/* expand 64bit on stack in two ints */
ST_FUNC void lexpand(void)
{
    int u, v;
    u = vtop->type.t & (VT_DEFSIGN | VT_UNSIGNED);
    v = vtop->r & (VT_VALMASK | VT_LVAL);
    if (v == VT_CONST) {
        vdup();
        vtop[0].c.i >>= 32;
    } else if (v == (VT_LVAL|VT_CONST) || v == (VT_LVAL|VT_LOCAL)) {
        vdup();
        vtop[0].c.i += 4;
    } else {
        gv(RC_INT);
        vdup();
        vtop[0].r = vtop[-1].r2;
        vtop[0].r2 = vtop[-1].r2 = VT_CONST;
    }
    vtop[0].type.t = vtop[-1].type.t = VT_INT | u;
}
#endif

#if PTR_SIZE == 4
/* build a long long from two ints */
static void lbuild(int t)
{
    gv2(RC_INT, RC_INT);
    vtop[-1].r2 = vtop[0].r;
    vtop[-1].type.t = t;
    vpop();
}
#endif

/* convert stack entry to register and duplicate its value in another
   register */
static void gv_dup(void)
{
    int rc, t, r, r1;
    SValue sv;

    t = vtop->type.t;
#if PTR_SIZE == 4
    if ((t & VT_BTYPE) == VT_LLONG) {
        if (t & VT_BITFIELD) {
            gv(RC_INT);
            t = vtop->type.t;
        }
        lexpand();
        gv_dup();
        vswap();
        vrotb(3);
        gv_dup();
        vrotb(4);
        /* stack: H L L1 H1 */
        lbuild(t);
        vrotb(3);
        vrotb(3);
        vswap();
        lbuild(t);
        vswap();
    } else
#endif
    {
        /* duplicate value */
        rc = RC_INT;
        sv.type.t = VT_INT;
        if (is_float(t)) {
            rc = RC_FLOAT;
#ifdef TCC_TARGET_X86_64
            if ((t & VT_BTYPE) == VT_LDOUBLE) {
                rc = RC_ST0;
            }
#endif
            sv.type.t = t;
        }
        r = gv(rc);
        r1 = get_reg(rc);
        sv.r = r;
        sv.c.i = 0;
        load(r1, &sv); /* move r to r1 */
        vdup();
        /* duplicates value */
        if (r != r1)
            vtop->r = r1;
    }
}

/* Generate value test
 *
 * Generate a test for any value (jump, comparison and integers) */
ST_FUNC int gvtst(int inv, int t)
{
    int v = vtop->r & VT_VALMASK;
    if (v != VT_CMP && v != VT_JMP && v != VT_JMPI) {
        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);
        vtop--;
        return t;
    }
    return gtst(inv, t);
}

#if PTR_SIZE == 4
/* generate CPU independent (unsigned) long long operations */
static void gen_opl(int op)
{
    int t, a, b, op1, c, i;
    int func;
    unsigned short reg_iret = REG_IRET;
    unsigned short reg_lret = REG_LRET;
    SValue tmp;

    switch(op) {
    case '/':
    case TOK_PDIV:
        func = TOK___divdi3;
        goto gen_func;
    case TOK_UDIV:
        func = TOK___udivdi3;
        goto gen_func;
    case '%':
        func = TOK___moddi3;
        goto gen_mod_func;
    case TOK_UMOD:
        func = TOK___umoddi3;
    gen_mod_func:
#ifdef TCC_ARM_EABI
        reg_iret = TREG_R2;
        reg_lret = TREG_R3;
#endif
    gen_func:
        /* call generic long long function */
        vpush_global_sym(&func_old_type, func);
        vrott(3);
        gfunc_call(2);
        vpushi(0);
        vtop->r = reg_iret;
        vtop->r2 = reg_lret;
        break;
    case '^':
    case '&':
    case '|':
    case '*':
    case '+':
    case '-':
        //pv("gen_opl A",0,2);
        t = vtop->type.t;
        vswap();
        lexpand();
        vrotb(3);
        lexpand();
        /* stack: L1 H1 L2 H2 */
        tmp = vtop[0];
        vtop[0] = vtop[-3];
        vtop[-3] = tmp;
        tmp = vtop[-2];
        vtop[-2] = vtop[-3];
        vtop[-3] = tmp;
        vswap();
        /* stack: H1 H2 L1 L2 */
        //pv("gen_opl B",0,4);
        if (op == '*') {
            vpushv(vtop - 1);
            vpushv(vtop - 1);
            gen_op(TOK_UMULL);
            lexpand();
            /* stack: H1 H2 L1 L2 ML MH */
            for(i=0;i<4;i++)
                vrotb(6);
            /* stack: ML MH H1 H2 L1 L2 */
            tmp = vtop[0];
            vtop[0] = vtop[-2];
            vtop[-2] = tmp;
            /* stack: ML MH H1 L2 H2 L1 */
            gen_op('*');
            vrotb(3);
            vrotb(3);
            gen_op('*');
            /* stack: ML MH M1 M2 */
            gen_op('+');
            gen_op('+');
        } else if (op == '+' || op == '-') {
            /* XXX: add non carry method too (for MIPS or alpha) */
            if (op == '+')
                op1 = TOK_ADDC1;
            else
                op1 = TOK_SUBC1;
            gen_op(op1);
            /* stack: H1 H2 (L1 op L2) */
            vrotb(3);
            vrotb(3);
            gen_op(op1 + 1); /* TOK_xxxC2 */
        } else {
            gen_op(op);
            /* stack: H1 H2 (L1 op L2) */
            vrotb(3);
            vrotb(3);
            /* stack: (L1 op L2) H1 H2 */
            gen_op(op);
            /* stack: (L1 op L2) (H1 op H2) */
        }
        /* stack: L H */
        lbuild(t);
        break;
    case TOK_SAR:
    case TOK_SHR:
    case TOK_SHL:
        if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
            t = vtop[-1].type.t;
            vswap();
            lexpand();
            vrotb(3);
            /* stack: L H shift */
            c = (int)vtop->c.i;
            /* constant: simpler */
            /* NOTE: all comments are for SHL. the other cases are
               done by swapping words */
            vpop();
            if (op != TOK_SHL)
                vswap();
            if (c >= 32) {
                /* stack: L H */
                vpop();
                if (c > 32) {
                    vpushi(c - 32);
                    gen_op(op);
                }
                if (op != TOK_SAR) {
                    vpushi(0);
                } else {
                    gv_dup();
                    vpushi(31);
                    gen_op(TOK_SAR);
                }
                vswap();
            } else {
                vswap();
                gv_dup();
                /* stack: H L L */
                vpushi(c);
                gen_op(op);
                vswap();
                vpushi(32 - c);
                if (op == TOK_SHL)
                    gen_op(TOK_SHR);
                else
                    gen_op(TOK_SHL);
                vrotb(3);
                /* stack: L L H */
                vpushi(c);
                if (op == TOK_SHL)
                    gen_op(TOK_SHL);
                else
                    gen_op(TOK_SHR);
                gen_op('|');
            }
            if (op != TOK_SHL)
                vswap();
            lbuild(t);
        } else {
            /* XXX: should provide a faster fallback on x86 ? */
            switch(op) {
            case TOK_SAR:
                func = TOK___ashrdi3;
                goto gen_func;
            case TOK_SHR:
                func = TOK___lshrdi3;
                goto gen_func;
            case TOK_SHL:
                func = TOK___ashldi3;
                goto gen_func;
            }
        }
        break;
    default:
        /* compare operations */
        t = vtop->type.t;
        vswap();
        lexpand();
        vrotb(3);
        lexpand();
        /* stack: L1 H1 L2 H2 */
        tmp = vtop[-1];
        vtop[-1] = vtop[-2];
        vtop[-2] = tmp;
        /* stack: L1 L2 H1 H2 */
        /* compare high */
        op1 = op;
        /* when values are equal, we need to compare low words. since
           the jump is inverted, we invert the test too. */
        if (op1 == TOK_LT)
            op1 = TOK_LE;
        else if (op1 == TOK_GT)
            op1 = TOK_GE;
        else if (op1 == TOK_ULT)
            op1 = TOK_ULE;
        else if (op1 == TOK_UGT)
            op1 = TOK_UGE;
        a = 0;
        b = 0;
        gen_op(op1);
        if (op == TOK_NE) {
            b = gvtst(0, 0);
        } else {
            a = gvtst(1, 0);
            if (op != TOK_EQ) {
                /* generate non equal test */
                vpushi(TOK_NE);
                vtop->r = VT_CMP;
                b = gvtst(0, 0);
            }
        }
        /* compare low. Always unsigned */
        op1 = op;
        if (op1 == TOK_LT)
            op1 = TOK_ULT;
        else if (op1 == TOK_LE)
            op1 = TOK_ULE;
        else if (op1 == TOK_GT)
            op1 = TOK_UGT;
        else if (op1 == TOK_GE)
            op1 = TOK_UGE;
        gen_op(op1);
        a = gvtst(1, a);
        gsym(b);
        vseti(VT_JMPI, a);
        break;
    }
}
#endif

static uint64_t gen_opic_sdiv(uint64_t a, uint64_t b)
{
    uint64_t x = (a >> 63 ? -a : a) / (b >> 63 ? -b : b);
    return (a ^ b) >> 63 ? -x : x;
}

static int gen_opic_lt(uint64_t a, uint64_t b)
{
    return (a ^ (uint64_t)1 << 63) < (b ^ (uint64_t)1 << 63);
}

/* handle integer constant optimizations and various machine
   independent opt */
static void gen_opic(int op)
{
    SValue *v1 = vtop - 1;
    SValue *v2 = vtop;
    int t1 = v1->type.t & VT_BTYPE;
    int t2 = v2->type.t & VT_BTYPE;
    int c1 = (v1->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    int c2 = (v2->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    uint64_t l1 = c1 ? v1->c.i : 0;
    uint64_t l2 = c2 ? v2->c.i : 0;
    int shm = (t1 == VT_LLONG) ? 63 : 31;

    if (t1 != VT_LLONG && (PTR_SIZE != 8 || t1 != VT_PTR))
        l1 = ((uint32_t)l1 |
              (v1->type.t & VT_UNSIGNED ? 0 : -(l1 & 0x80000000)));
    if (t2 != VT_LLONG && (PTR_SIZE != 8 || t2 != VT_PTR))
        l2 = ((uint32_t)l2 |
              (v2->type.t & VT_UNSIGNED ? 0 : -(l2 & 0x80000000)));

    if (c1 && c2) {
        switch(op) {
        case '+': l1 += l2; break;
        case '-': l1 -= l2; break;
        case '&': l1 &= l2; break;
        case '^': l1 ^= l2; break;
        case '|': l1 |= l2; break;
        case '*': l1 *= l2; break;

        case TOK_PDIV:
        case '/':
        case '%':
        case TOK_UDIV:
        case TOK_UMOD:
            /* if division by zero, generate explicit division */
            if (l2 == 0) {
                if (const_wanted)
                    tcc_error("division by zero in constant");
                goto general_case;
            }
            switch(op) {
            default: l1 = gen_opic_sdiv(l1, l2); break;
            case '%': l1 = l1 - l2 * gen_opic_sdiv(l1, l2); break;
            case TOK_UDIV: l1 = l1 / l2; break;
            case TOK_UMOD: l1 = l1 % l2; break;
            }
            break;
        case TOK_SHL: l1 <<= (l2 & shm); break;
        case TOK_SHR: l1 >>= (l2 & shm); break;
        case TOK_SAR:
            l1 = (l1 >> 63) ? ~(~l1 >> (l2 & shm)) : l1 >> (l2 & shm);
            break;
            /* tests */
        case TOK_ULT: l1 = l1 < l2; break;
        case TOK_UGE: l1 = l1 >= l2; break;
        case TOK_EQ: l1 = l1 == l2; break;
        case TOK_NE: l1 = l1 != l2; break;
        case TOK_ULE: l1 = l1 <= l2; break;
        case TOK_UGT: l1 = l1 > l2; break;
        case TOK_LT: l1 = gen_opic_lt(l1, l2); break;
        case TOK_GE: l1 = !gen_opic_lt(l1, l2); break;
        case TOK_LE: l1 = !gen_opic_lt(l2, l1); break;
        case TOK_GT: l1 = gen_opic_lt(l2, l1); break;
            /* logical */
        case TOK_LAND: l1 = l1 && l2; break;
        case TOK_LOR: l1 = l1 || l2; break;
        default:
            goto general_case;
        }
        if (t1 != VT_LLONG && (PTR_SIZE != 8 || t1 != VT_PTR))
            l1 = ((uint32_t)l1 |
                (v1->type.t & VT_UNSIGNED ? 0 : -(l1 & 0x80000000)));
        v1->c.i = l1;
        vtop--;
    } else {
        /* if commutative ops, put c2 as constant */
        if (c1 && (op == '+' || op == '&' || op == '^' || 
                   op == '|' || op == '*')) {
            vswap();
            c2 = c1; //c = c1, c1 = c2, c2 = c;
            l2 = l1; //l = l1, l1 = l2, l2 = l;
        }
        if (!const_wanted &&
            c1 && ((l1 == 0 &&
                    (op == TOK_SHL || op == TOK_SHR || op == TOK_SAR)) ||
                   (l1 == -1 && op == TOK_SAR))) {
            /* treat (0 << x), (0 >> x) and (-1 >> x) as constant */
            vtop--;
        } else if (!const_wanted &&
                   c2 && ((l2 == 0 && (op == '&' || op == '*')) ||
                          (op == '|' &&
                            (l2 == -1 || (l2 == 0xFFFFFFFF && t2 != VT_LLONG))) ||
                          (l2 == 1 && (op == '%' || op == TOK_UMOD)))) {
            /* treat (x & 0), (x * 0), (x | -1) and (x % 1) as constant */
            if (l2 == 1)
                vtop->c.i = 0;
            vswap();
            vtop--;
        } else if (c2 && (((op == '*' || op == '/' || op == TOK_UDIV ||
                          op == TOK_PDIV) &&
                           l2 == 1) ||
                          ((op == '+' || op == '-' || op == '|' || op == '^' ||
                            op == TOK_SHL || op == TOK_SHR || op == TOK_SAR) &&
                           l2 == 0) ||
                          (op == '&' &&
                            (l2 == -1 || (l2 == 0xFFFFFFFF && t2 != VT_LLONG))))) {
            /* filter out NOP operations like x*1, x-0, x&-1... */
            vtop--;
        } else if (c2 && (op == '*' || op == TOK_PDIV || op == TOK_UDIV)) {
            /* try to use shifts instead of muls or divs */
            if (l2 > 0 && (l2 & (l2 - 1)) == 0) {
                int n = -1;
                while (l2) {
                    l2 >>= 1;
                    n++;
                }
                vtop->c.i = n;
                if (op == '*')
                    op = TOK_SHL;
                else if (op == TOK_PDIV)
                    op = TOK_SAR;
                else
                    op = TOK_SHR;
            }
            goto general_case;
        } else if (c2 && (op == '+' || op == '-') &&
                   (((vtop[-1].r & (VT_VALMASK | VT_LVAL | VT_SYM)) == (VT_CONST | VT_SYM))
                    || (vtop[-1].r & (VT_VALMASK | VT_LVAL)) == VT_LOCAL)) {
            /* symbol + constant case */
            if (op == '-')
                l2 = -l2;
            l2 += vtop[-1].c.i;
            /* The backends can't always deal with addends to symbols
               larger than +-1<<31.  Don't construct such.  */
            if ((int)l2 != l2)
                goto general_case;
            vtop--;
            vtop->c.i = l2;
        } else {
        general_case:
                /* call low level op generator */
                if (t1 == VT_LLONG || t2 == VT_LLONG ||
                    (PTR_SIZE == 8 && (t1 == VT_PTR || t2 == VT_PTR)))
                    gen_opl(op);
                else
                    gen_opi(op);
        }
    }
}

/* generate a floating point operation with constant propagation */
static void gen_opif(int op)
{
    int c1, c2;
    SValue *v1, *v2;
#if defined _MSC_VER && defined _AMD64_
    /* avoid bad optimization with f1 -= f2 for f1:-0.0, f2:0.0 */
    volatile
#endif
    long double f1, f2;

    v1 = vtop - 1;
    v2 = vtop;
    /* currently, we cannot do computations with forward symbols */
    c1 = (v1->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    c2 = (v2->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    if (c1 && c2) {
        if (v1->type.t == VT_FLOAT) {
            f1 = v1->c.f;
            f2 = v2->c.f;
        } else if (v1->type.t == VT_DOUBLE) {
            f1 = v1->c.d;
            f2 = v2->c.d;
        } else {
            f1 = v1->c.ld;
            f2 = v2->c.ld;
        }

        /* NOTE: we only do constant propagation if finite number (not
           NaN or infinity) (ANSI spec) */
        if (!ieee_finite(f1) || !ieee_finite(f2))
            goto general_case;

        switch(op) {
        case '+': f1 += f2; break;
        case '-': f1 -= f2; break;
        case '*': f1 *= f2; break;
        case '/': 
            if (f2 == 0.0) {
                /* If not in initializer we need to potentially generate
                   FP exceptions at runtime, otherwise we want to fold.  */
                if (!const_wanted)
                    goto general_case;
            }
            f1 /= f2; 
            break;
            /* XXX: also handles tests ? */
        default:
            goto general_case;
        }
        /* XXX: overflow test ? */
        if (v1->type.t == VT_FLOAT) {
            v1->c.f = f1;
        } else if (v1->type.t == VT_DOUBLE) {
            v1->c.d = f1;
        } else {
            v1->c.ld = f1;
        }
        vtop--;
    } else {
    general_case:
        gen_opf(op);
    }
}

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

static void vla_runtime_pointed_size(CType *type)
{
    int align;
    vla_runtime_type_size(pointed_type(type), &align);
}

static inline int is_null_pointer(SValue *p)
{
    if ((p->r & (VT_VALMASK | VT_LVAL | VT_SYM)) != VT_CONST)
        return 0;
    return ((p->type.t & VT_BTYPE) == VT_INT && (uint32_t)p->c.i == 0) ||
        ((p->type.t & VT_BTYPE) == VT_LLONG && p->c.i == 0) ||
        ((p->type.t & VT_BTYPE) == VT_PTR &&
         (PTR_SIZE == 4 ? (uint32_t)p->c.i == 0 : p->c.i == 0) &&
         ((pointed_type(&p->type)->t & VT_BTYPE) == VT_VOID) &&
         0 == (pointed_type(&p->type)->t & (VT_CONSTANT | VT_VOLATILE))
         );
}
static inline int is_integer_btype(int bt)
{
    return (bt == VT_BYTE || bt == VT_SHORT || 
            bt == VT_INT || bt == VT_LLONG);
}

/* check types for comparison or subtraction of pointers */
static void check_comparison_pointer_types(SValue *p1, SValue *p2, int op)
{
    CType *type1, *type2, tmp_type1, tmp_type2;
    int bt1, bt2;
    
    /* null pointers are accepted for all comparisons as gcc */
    if (is_null_pointer(p1) || is_null_pointer(p2))
        return;
    type1 = &p1->type;
    type2 = &p2->type;
    bt1 = type1->t & VT_BTYPE;
    bt2 = type2->t & VT_BTYPE;
    /* accept comparison between pointer and integer with a warning */
    if ((is_integer_btype(bt1) || is_integer_btype(bt2)) && op != '-') {
        if (op != TOK_LOR && op != TOK_LAND )
            tcc_warning("comparison between pointer and integer");
        return;
    }

    /* both must be pointers or implicit function pointers */
    if (bt1 == VT_PTR) {
        type1 = pointed_type(type1);
    } else if (bt1 != VT_FUNC) 
        goto invalid_operands;

    if (bt2 == VT_PTR) {
        type2 = pointed_type(type2);
    } else if (bt2 != VT_FUNC) { 
    invalid_operands:
        tcc_error("invalid operands to binary %s", get_tok_str(op, NULL));
    }
    if ((type1->t & VT_BTYPE) == VT_VOID || 
        (type2->t & VT_BTYPE) == VT_VOID)
        return;
    tmp_type1 = *type1;
    tmp_type2 = *type2;
    tmp_type1.t &= ~(VT_DEFSIGN | VT_UNSIGNED | VT_CONSTANT | VT_VOLATILE);
    tmp_type2.t &= ~(VT_DEFSIGN | VT_UNSIGNED | VT_CONSTANT | VT_VOLATILE);
    if (!is_compatible_types(&tmp_type1, &tmp_type2)) {
        /* gcc-like error if '-' is used */
        if (op == '-')
            goto invalid_operands;
        else
            tcc_warning("comparison of distinct pointer types lacks a cast");
    }
}

/* generic gen_op: handles types problems */
ST_FUNC void gen_op(int op)
{
    int u, t1, t2, bt1, bt2, t;
    CType type1;

redo:
    t1 = vtop[-1].type.t;
    t2 = vtop[0].type.t;
    bt1 = t1 & VT_BTYPE;
    bt2 = t2 & VT_BTYPE;
        
    if (bt1 == VT_STRUCT || bt2 == VT_STRUCT) {
        tcc_error("operation on a struct");
    } else if (bt1 == VT_FUNC || bt2 == VT_FUNC) {
        if (bt2 == VT_FUNC) {
            mk_pointer(&vtop->type);
            gaddrof();
        }
        if (bt1 == VT_FUNC) {
            vswap();
            mk_pointer(&vtop->type);
            gaddrof();
            vswap();
        }
        goto redo;
    } else if (bt1 == VT_PTR || bt2 == VT_PTR) {
        /* at least one operand is a pointer */
        /* relational op: must be both pointers */
        if (op >= TOK_ULT && op <= TOK_LOR) {
            check_comparison_pointer_types(vtop - 1, vtop, op);
            /* pointers are handled are unsigned */
#if PTR_SIZE == 8
            t = VT_LLONG | VT_UNSIGNED;
#else
            t = VT_INT | VT_UNSIGNED;
#endif
            goto std_op;
        }
        /* if both pointers, then it must be the '-' op */
        if (bt1 == VT_PTR && bt2 == VT_PTR) {
            if (op != '-')
                tcc_error("cannot use pointers here");
            check_comparison_pointer_types(vtop - 1, vtop, op);
            /* XXX: check that types are compatible */
            if (vtop[-1].type.t & VT_VLA) {
                vla_runtime_pointed_size(&vtop[-1].type);
            } else {
                vpushi(pointed_size(&vtop[-1].type));
            }
            vrott(3);
            gen_opic(op);
            vtop->type.t = ptrdiff_type.t;
            vswap();
            gen_op(TOK_PDIV);
        } else {
            /* exactly one pointer : must be '+' or '-'. */
            if (op != '-' && op != '+')
                tcc_error("cannot use pointers here");
            /* Put pointer as first operand */
            if (bt2 == VT_PTR) {
                vswap();
                t = t1, t1 = t2, t2 = t;
            }
#if PTR_SIZE == 4
            if ((vtop[0].type.t & VT_BTYPE) == VT_LLONG)
                /* XXX: truncate here because gen_opl can't handle ptr + long long */
                gen_cast_s(VT_INT);
#endif
            type1 = vtop[-1].type;
            type1.t &= ~VT_ARRAY;
            if (vtop[-1].type.t & VT_VLA)
                vla_runtime_pointed_size(&vtop[-1].type);
            else {
                u = pointed_size(&vtop[-1].type);
                if (u < 0)
                    tcc_error("unknown array element size");
#if PTR_SIZE == 8
                vpushll(u);
#else
                /* XXX: cast to int ? (long long case) */
                vpushi(u);
#endif
            }
            gen_op('*');
#if 0
/* #ifdef CONFIG_TCC_BCHECK
    The main reason to removing this code:
        #include <stdio.h>
        int main ()
        {
            int v[10];
            int i = 10;
            int j = 9;
            fprintf(stderr, "v+i-j  = %p\n", v+i-j);
            fprintf(stderr, "v+(i-j)  = %p\n", v+(i-j));
        }
    When this code is on. then the output looks like 
        v+i-j = 0xfffffffe
        v+(i-j) = 0xbff84000
    */
            /* if evaluating constant expression, no code should be
               generated, so no bound check */
            if (tcc_state->do_bounds_check && !const_wanted) {
                /* if bounded pointers, we generate a special code to
                   test bounds */
                if (op == '-') {
                    vpushi(0);
                    vswap();
                    gen_op('-');
                }
                gen_bounded_ptr_add();
            } else
#endif
            {
                gen_opic(op);
            }
            /* put again type if gen_opic() swaped operands */
            vtop->type = type1;
        }
    } else if (is_float(bt1) || is_float(bt2)) {
        /* compute bigger type and do implicit casts */
        if (bt1 == VT_LDOUBLE || bt2 == VT_LDOUBLE) {
            t = VT_LDOUBLE;
        } else if (bt1 == VT_DOUBLE || bt2 == VT_DOUBLE) {
            t = VT_DOUBLE;
        } else {
            t = VT_FLOAT;
        }
        /* floats can only be used for a few operations */
        if (op != '+' && op != '-' && op != '*' && op != '/' &&
            (op < TOK_ULT || op > TOK_GT))
            tcc_error("invalid operands for binary operation");
        goto std_op;
    } else if (op == TOK_SHR || op == TOK_SAR || op == TOK_SHL) {
        t = bt1 == VT_LLONG ? VT_LLONG : VT_INT;
        if ((t1 & (VT_BTYPE | VT_UNSIGNED | VT_BITFIELD)) == (t | VT_UNSIGNED))
          t |= VT_UNSIGNED;
        t |= (VT_LONG & t1);
        goto std_op;
    } else if (bt1 == VT_LLONG || bt2 == VT_LLONG) {
        /* cast to biggest op */
        t = VT_LLONG | VT_LONG;
        if (bt1 == VT_LLONG)
            t &= t1;
        if (bt2 == VT_LLONG)
            t &= t2;
        /* convert to unsigned if it does not fit in a long long */
        if ((t1 & (VT_BTYPE | VT_UNSIGNED | VT_BITFIELD)) == (VT_LLONG | VT_UNSIGNED) ||
            (t2 & (VT_BTYPE | VT_UNSIGNED | VT_BITFIELD)) == (VT_LLONG | VT_UNSIGNED))
            t |= VT_UNSIGNED;
        goto std_op;
    } else {
        /* integer operations */
        t = VT_INT | (VT_LONG & (t1 | t2));
        /* convert to unsigned if it does not fit in an integer */
        if ((t1 & (VT_BTYPE | VT_UNSIGNED | VT_BITFIELD)) == (VT_INT | VT_UNSIGNED) ||
            (t2 & (VT_BTYPE | VT_UNSIGNED | VT_BITFIELD)) == (VT_INT | VT_UNSIGNED))
            t |= VT_UNSIGNED;
    std_op:
        /* XXX: currently, some unsigned operations are explicit, so
           we modify them here */
        if (t & VT_UNSIGNED) {
            if (op == TOK_SAR)
                op = TOK_SHR;
            else if (op == '/')
                op = TOK_UDIV;
            else if (op == '%')
                op = TOK_UMOD;
            else if (op == TOK_LT)
                op = TOK_ULT;
            else if (op == TOK_GT)
                op = TOK_UGT;
            else if (op == TOK_LE)
                op = TOK_ULE;
            else if (op == TOK_GE)
                op = TOK_UGE;
        }
        vswap();
        type1.t = t;
        type1.ref = NULL;
        gen_cast(&type1);
        vswap();
        /* special case for shifts and long long: we keep the shift as
           an integer */
        if (op == TOK_SHR || op == TOK_SAR || op == TOK_SHL)
            type1.t = VT_INT;
        gen_cast(&type1);
        if (is_float(t))
            gen_opif(op);
        else
            gen_opic(op);
        if (op >= TOK_ULT && op <= TOK_GT) {
            /* relational op: the result is an int */
            vtop->type.t = VT_INT;
        } else {
            vtop->type.t = t;
        }
    }
    // Make sure that we have converted to an rvalue:
    if (vtop->r & VT_LVAL)
        gv(is_float(vtop->type.t & VT_BTYPE) ? RC_FLOAT : RC_INT);
}

#ifndef TCC_TARGET_ARM
/* generic itof for unsigned long long case */
static void gen_cvt_itof1(int t)
{
#ifdef TCC_TARGET_ARM64
    gen_cvt_itof(t);
#else
    if ((vtop->type.t & (VT_BTYPE | VT_UNSIGNED)) == 
        (VT_LLONG | VT_UNSIGNED)) {

        if (t == VT_FLOAT)
            vpush_global_sym(&func_old_type, TOK___floatundisf);
#if LDOUBLE_SIZE != 8
        else if (t == VT_LDOUBLE)
            vpush_global_sym(&func_old_type, TOK___floatundixf);
#endif
        else
            vpush_global_sym(&func_old_type, TOK___floatundidf);
        vrott(2);
        gfunc_call(1);
        vpushi(0);
        vtop->r = reg_fret(t);
    } else {
        gen_cvt_itof(t);
    }
#endif
}
#endif

/* generic ftoi for unsigned long long case */
static void gen_cvt_ftoi1(int t)
{
#ifdef TCC_TARGET_ARM64
    gen_cvt_ftoi(t);
#else
    int st;

    if (t == (VT_LLONG | VT_UNSIGNED)) {
        /* not handled natively */
        st = vtop->type.t & VT_BTYPE;
        if (st == VT_FLOAT)
            vpush_global_sym(&func_old_type, TOK___fixunssfdi);
#if LDOUBLE_SIZE != 8
        else if (st == VT_LDOUBLE)
            vpush_global_sym(&func_old_type, TOK___fixunsxfdi);
#endif
        else
            vpush_global_sym(&func_old_type, TOK___fixunsdfdi);
        vrott(2);
        gfunc_call(1);
        vpushi(0);
        vtop->r = REG_IRET;
        vtop->r2 = REG_LRET;
    } else {
        gen_cvt_ftoi(t);
    }
#endif
}

/* force char or short cast */
static void force_charshort_cast(int t)
{
    int bits, dbt;

    /* cannot cast static initializers */
    if (STATIC_DATA_WANTED)
        return;

    dbt = t & VT_BTYPE;
    /* XXX: add optimization if lvalue : just change type and offset */
    if (dbt == VT_BYTE)
        bits = 8;
    else
        bits = 16;
    if (t & VT_UNSIGNED) {
        vpushi((1 << bits) - 1);
        gen_op('&');
    } else {
        if ((vtop->type.t & VT_BTYPE) == VT_LLONG)
            bits = 64 - bits;
        else
            bits = 32 - bits;
        vpushi(bits);
        gen_op(TOK_SHL);
        /* result must be signed or the SAR is converted to an SHL
           This was not the case when "t" was a signed short
           and the last value on the stack was an unsigned int */
        vtop->type.t &= ~VT_UNSIGNED;
        vpushi(bits);
        gen_op(TOK_SAR);
    }
}

/* cast 'vtop' to 'type'. Casting to bitfields is forbidden. */
static void gen_cast_s(int t)
{
    CType type;
    type.t = t;
    type.ref = NULL;
    gen_cast(&type);
}

static void gen_cast(CType *type)
{
    int sbt, dbt, sf, df, c, p;

    /* special delayed cast for char/short */
    /* XXX: in some cases (multiple cascaded casts), it may still
       be incorrect */
    if (vtop->r & VT_MUSTCAST) {
        vtop->r &= ~VT_MUSTCAST;
        force_charshort_cast(vtop->type.t);
    }

    /* bitfields first get cast to ints */
    if (vtop->type.t & VT_BITFIELD) {
        gv(RC_INT);
    }

    dbt = type->t & (VT_BTYPE | VT_UNSIGNED);
    sbt = vtop->type.t & (VT_BTYPE | VT_UNSIGNED);

    if (sbt != dbt) {
        sf = is_float(sbt);
        df = is_float(dbt);
        c = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
        p = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == (VT_CONST | VT_SYM);
#if !defined TCC_IS_NATIVE && !defined TCC_IS_NATIVE_387
        c &= dbt != VT_LDOUBLE;
#endif
        if (c) {
            /* constant case: we can do it now */
            /* XXX: in ISOC, cannot do it if error in convert */
            if (sbt == VT_FLOAT)
                vtop->c.ld = vtop->c.f;
            else if (sbt == VT_DOUBLE)
                vtop->c.ld = vtop->c.d;

            if (df) {
                if ((sbt & VT_BTYPE) == VT_LLONG) {
                    if ((sbt & VT_UNSIGNED) || !(vtop->c.i >> 63))
                        vtop->c.ld = vtop->c.i;
                    else
                        vtop->c.ld = -(long double)-vtop->c.i;
                } else if(!sf) {
                    if ((sbt & VT_UNSIGNED) || !(vtop->c.i >> 31))
                        vtop->c.ld = (uint32_t)vtop->c.i;
                    else
                        vtop->c.ld = -(long double)-(uint32_t)vtop->c.i;
                }

                if (dbt == VT_FLOAT)
                    vtop->c.f = (float)vtop->c.ld;
                else if (dbt == VT_DOUBLE)
                    vtop->c.d = (double)vtop->c.ld;
            } else if (sf && dbt == (VT_LLONG|VT_UNSIGNED)) {
                vtop->c.i = vtop->c.ld;
            } else if (sf && dbt == VT_BOOL) {
                vtop->c.i = (vtop->c.ld != 0);
            } else {
                if(sf)
                    vtop->c.i = vtop->c.ld;
                else if (sbt == (VT_LLONG|VT_UNSIGNED))
                    ;
                else if (sbt & VT_UNSIGNED)
                    vtop->c.i = (uint32_t)vtop->c.i;
#if PTR_SIZE == 8
                else if (sbt == VT_PTR)
                    ;
#endif
                else if (sbt != VT_LLONG)
                    vtop->c.i = ((uint32_t)vtop->c.i |
                                  -(vtop->c.i & 0x80000000));

                if (dbt == (VT_LLONG|VT_UNSIGNED))
                    ;
                else if (dbt == VT_BOOL)
                    vtop->c.i = (vtop->c.i != 0);
#if PTR_SIZE == 8
                else if (dbt == VT_PTR)
                    ;
#endif
                else if (dbt != VT_LLONG) {
                    uint32_t m = ((dbt & VT_BTYPE) == VT_BYTE ? 0xff :
                                  (dbt & VT_BTYPE) == VT_SHORT ? 0xffff :
                                  0xffffffff);
                    vtop->c.i &= m;
                    if (!(dbt & VT_UNSIGNED))
                        vtop->c.i |= -(vtop->c.i & ((m >> 1) + 1));
                }
            }
        } else if (p && dbt == VT_BOOL) {
            vtop->r = VT_CONST;
            vtop->c.i = 1;
        } else {
            /* non constant case: generate code */
            if (sf && df) {
                /* convert from fp to fp */
                gen_cvt_ftof(dbt);
            } else if (df) {
                /* convert int to fp */
                gen_cvt_itof1(dbt);
            } else if (sf) {
                /* convert fp to int */
                if (dbt == VT_BOOL) {
                     vpushi(0);
                     gen_op(TOK_NE);
                } else {
                    /* we handle char/short/etc... with generic code */
                    if (dbt != (VT_INT | VT_UNSIGNED) &&
                        dbt != (VT_LLONG | VT_UNSIGNED) &&
                        dbt != VT_LLONG)
                        dbt = VT_INT;
                    gen_cvt_ftoi1(dbt);
                    if (dbt == VT_INT && (type->t & (VT_BTYPE | VT_UNSIGNED)) != dbt) {
                        /* additional cast for char/short... */
                        vtop->type.t = dbt;
                        gen_cast(type);
                    }
                }
#if PTR_SIZE == 4
            } else if ((dbt & VT_BTYPE) == VT_LLONG) {
                if ((sbt & VT_BTYPE) != VT_LLONG) {
                    /* scalar to long long */
                    /* machine independent conversion */
                    gv(RC_INT);
                    /* generate high word */
                    if (sbt == (VT_INT | VT_UNSIGNED)) {
                        vpushi(0);
                        gv(RC_INT);
                    } else {
                        if (sbt == VT_PTR) {
                            /* cast from pointer to int before we apply
                               shift operation, which pointers don't support*/
                            gen_cast_s(VT_INT);
                        }
                        gv_dup();
                        vpushi(31);
                        gen_op(TOK_SAR);
                    }
                    /* patch second register */
                    vtop[-1].r2 = vtop->r;
                    vpop();
                }
#else
            } else if ((dbt & VT_BTYPE) == VT_LLONG ||
                       (dbt & VT_BTYPE) == VT_PTR ||
                       (dbt & VT_BTYPE) == VT_FUNC) {
                if ((sbt & VT_BTYPE) != VT_LLONG &&
                    (sbt & VT_BTYPE) != VT_PTR &&
                    (sbt & VT_BTYPE) != VT_FUNC) {
                    /* need to convert from 32bit to 64bit */
                    gv(RC_INT);
                    if (sbt != (VT_INT | VT_UNSIGNED)) {
#if defined(TCC_TARGET_ARM64)
                        gen_cvt_sxtw();
#elif defined(TCC_TARGET_X86_64)
                        int r = gv(RC_INT);
                        /* x86_64 specific: movslq */
                        o(0x6348);
                        o(0xc0 + (REG_VALUE(r) << 3) + REG_VALUE(r));
#else
#error
#endif
                    }
                }
#endif
            } else if (dbt == VT_BOOL) {
                /* scalar to bool */
                vpushi(0);
                gen_op(TOK_NE);
            } else if ((dbt & VT_BTYPE) == VT_BYTE || 
                       (dbt & VT_BTYPE) == VT_SHORT) {
                if (sbt == VT_PTR) {
                    vtop->type.t = VT_INT;
                    tcc_warning("nonportable conversion from pointer to char/short");
                }
                force_charshort_cast(dbt);
            } else if ((dbt & VT_BTYPE) == VT_INT) {
                /* scalar to int */
                if ((sbt & VT_BTYPE) == VT_LLONG) {
#if PTR_SIZE == 4
                    /* from long long: just take low order word */
                    lexpand();
                    vpop();
#else
                    vpushi(0xffffffff);
                    vtop->type.t |= VT_UNSIGNED;
                    gen_op('&');
#endif
                }
                /* if lvalue and single word type, nothing to do because
                   the lvalue already contains the real type size (see
                   VT_LVAL_xxx constants) */
            }
        }
    } else if ((dbt & VT_BTYPE) == VT_PTR && !(vtop->r & VT_LVAL)) {
        /* if we are casting between pointer types,
           we must update the VT_LVAL_xxx size */
        vtop->r = (vtop->r & ~VT_LVAL_TYPE)
                  | (lvalue_type(type->ref->type.t) & VT_LVAL_TYPE);
    }
    vtop->type = *type;
    vtop->type.t &= ~ ( VT_CONSTANT | VT_VOLATILE | VT_ARRAY );
}

/* return type size as known at compile time. Put alignment at 'a' */
ST_FUNC 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 < 0) {
        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;
    }
}

/* push type size as known at runtime time on top of value stack. Put
   alignment at 'a' */
ST_FUNC void vla_runtime_type_size(CType *type, int *a)
{
    if (type->t & VT_VLA) {
        type_size(&type->ref->type, a);
        vset(&int_type, VT_LOCAL|VT_LVAL, type->ref->c);
    } else {
        vpushi(type_size(type, a));
    }
}

static void vla_sp_restore(void) {
    if (vlas_in_scope) {
        gen_vla_sp_restore(vla_sp_loc);
    }
}

static void vla_sp_restore_root(void) {
    if (vlas_in_scope) {
        gen_vla_sp_restore(vla_sp_root_loc);
    }
}

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

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

/* 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.
 */
static 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 | VT_ARRAY);
    if (bt1 == VT_PTR) {
        type1 = pointed_type(type1);
        type2 = pointed_type(type2);
        return is_compatible_types(type1, type2);
    } else if (bt1 & VT_ARRAY) {
        return type1->ref->c < 0 || type2->ref->c < 0
            || type1->ref->c == type2->ref->c;
    } else if (bt1 == VT_STRUCT) {
        return (type1->ref == type2->ref);
    } else if (bt1 == VT_FUNC) {
        return is_compatible_func(type1, type2);
    } else if (IS_ENUM(type1->t) || IS_ENUM(type2->t)) {
        return type1->ref == type2->ref;
    } else {
        return 1;
    }
}

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

/* 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 */
static 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;
        buf1[0]=0;
        if (varstr && '*' == *varstr) {
            pstrcat(buf1, sizeof(buf1), "(");
            pstrcat(buf1, sizeof(buf1), varstr);
            pstrcat(buf1, sizeof(buf1), ")");
        }
        pstrcat(buf1, buf_size, "(");
        sa = s->next;
        while (sa != NULL) {
            char buf2[256];
            type_to_str(buf2, sizeof(buf2), &sa->type, NULL);
            pstrcat(buf1, sizeof(buf1), buf2);
            sa = sa->next;
            if (sa)
                pstrcat(buf1, sizeof(buf1), ", ");
        }
        if (s->f.func_type == FUNC_ELLIPSIS)
            pstrcat(buf1, sizeof(buf1), ", ...");
        pstrcat(buf1, sizeof(buf1), ")");
        type_to_str(buf, buf_size, &s->type, buf1);
        goto no_var;
    case VT_PTR:
        s = type->ref;
        if (t & VT_ARRAY) {
            if (varstr && '*' == *varstr)
                snprintf(buf1, sizeof(buf1), "(%s)[%d]", varstr, s->c);
            else
                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: ;
}

/* verify type compatibility to store vtop in 'dt' type, and generate
   casts if needed. */
static void gen_assign_cast(CType *dt)
{
    CType *st, *type1, *type2;
    char buf1[256], buf2[256];
    int dbt, sbt, qualwarn, lvl;

    st = &vtop->type; /* source type */
    dbt = dt->t & VT_BTYPE;
    sbt = st->t & VT_BTYPE;
    if (sbt == VT_VOID || dbt == VT_VOID) {
        if (sbt == VT_VOID && dbt == VT_VOID)
            ; /* It is Ok if both are void */
        else
            tcc_error("cannot cast from/to void");
    }
    if (dt->t & VT_CONSTANT)
        tcc_warning("assignment of read-only location");
    switch(dbt) {
    case VT_PTR:
        /* special cases for pointers */
        /* '0' can also be a pointer */
        if (is_null_pointer(vtop))
            break;
        /* accept implicit pointer to integer cast with warning */
        if (is_integer_btype(sbt)) {
            tcc_warning("assignment makes pointer from integer without a cast");
            break;
        }
        type1 = pointed_type(dt);
        if (sbt == VT_PTR)
            type2 = pointed_type(st);
        else if (sbt == VT_FUNC)
            type2 = st; /* a function is implicitly a function pointer */
        else
            goto error;
        if (is_compatible_types(type1, type2))
            break;
        for (qualwarn = lvl = 0;; ++lvl) {
            if (((type2->t & VT_CONSTANT) && !(type1->t & VT_CONSTANT)) ||
                ((type2->t & VT_VOLATILE) && !(type1->t & VT_VOLATILE)))
                qualwarn = 1;
            dbt = type1->t & (VT_BTYPE|VT_LONG);
            sbt = type2->t & (VT_BTYPE|VT_LONG);
            if (dbt != VT_PTR || sbt != VT_PTR)
                break;
            type1 = pointed_type(type1);
            type2 = pointed_type(type2);
        }
        if (!is_compatible_unqualified_types(type1, type2)) {
            if ((dbt == VT_VOID || sbt == VT_VOID) && lvl == 0) {
                /* void * can match anything */
            } else if (dbt == sbt
                && is_integer_btype(sbt & VT_BTYPE)
                && IS_ENUM(type1->t) + IS_ENUM(type2->t)
                    + !!((type1->t ^ type2->t) & VT_UNSIGNED) < 2) {
                /* Like GCC don't warn by default for merely changes
                   in pointer target signedness.  Do warn for different
                   base types, though, in particular for unsigned enums
                   and signed int targets.  */
            } else {
                tcc_warning("assignment from incompatible pointer type");
                break;
            }
        }
        if (qualwarn)
            tcc_warning("assignment discards qualifiers from pointer target type");
        break;
    case VT_BYTE:
    case VT_SHORT:
    case VT_INT:
    case VT_LLONG:
        if (sbt == VT_PTR || sbt == VT_FUNC) {
            tcc_warning("assignment makes integer from pointer without a cast");
        } else if (sbt == VT_STRUCT) {
            goto case_VT_STRUCT;
        }
        /* XXX: more tests */
        break;
    case VT_STRUCT:
    case_VT_STRUCT:
        if (!is_compatible_unqualified_types(dt, st)) {
        error:
            type_to_str(buf1, sizeof(buf1), st, NULL);
            type_to_str(buf2, sizeof(buf2), dt, NULL);
            tcc_error("cannot cast '%s' to '%s'", buf1, buf2);
        }
        break;
    }
    gen_cast(dt);
}

/* store vtop in lvalue pushed on stack */
ST_FUNC void vstore(void)
{
    int sbt, dbt, ft, r, t, size, align, bit_size, bit_pos, rc, delayed_cast;

    ft = vtop[-1].type.t;
    sbt = vtop->type.t & VT_BTYPE;
    dbt = ft & VT_BTYPE;
    if ((((sbt == VT_INT || sbt == VT_SHORT) && dbt == VT_BYTE) ||
         (sbt == VT_INT && dbt == VT_SHORT))
        && !(vtop->type.t & VT_BITFIELD)) {
        /* optimize char/short casts */
        delayed_cast = VT_MUSTCAST;
        vtop->type.t = ft & VT_TYPE;
        /* XXX: factorize */
        if (ft & VT_CONSTANT)
            tcc_warning("assignment of read-only location");
    } else {
        delayed_cast = 0;
        if (!(ft & VT_BITFIELD))
            gen_assign_cast(&vtop[-1].type);
    }

    if (sbt == VT_STRUCT) {
        /* if structure, only generate pointer */
        /* structure assignment : generate memcpy */
        /* XXX: optimize if small size */
            size = type_size(&vtop->type, &align);

            /* destination */
            vswap();
            vtop->type.t = VT_PTR;
            gaddrof();

            /* address of memcpy() */
#ifdef TCC_ARM_EABI
            if(!(align & 7))
                vpush_global_sym(&func_old_type, TOK_memcpy8);
            else if(!(align & 3))
                vpush_global_sym(&func_old_type, TOK_memcpy4);
            else
#endif
            /* Use memmove, rather than memcpy, as dest and src may be same: */
            vpush_global_sym(&func_old_type, TOK_memmove);

            vswap();
            /* source */
            vpushv(vtop - 2);
            vtop->type.t = VT_PTR;
            gaddrof();
            /* type size */
            vpushi(size);
            gfunc_call(3);

        /* leave source on stack */
    } else if (ft & VT_BITFIELD) {
        /* bitfield store handling */

        /* save lvalue as expression result (example: s.b = s.a = n;) */
        vdup(), vtop[-1] = vtop[-2];

        bit_pos = BIT_POS(ft);
        bit_size = BIT_SIZE(ft);
        /* remove bit field info to avoid loops */
        vtop[-1].type.t = ft & ~VT_STRUCT_MASK;

        if ((ft & VT_BTYPE) == VT_BOOL) {
            gen_cast(&vtop[-1].type);
            vtop[-1].type.t = (vtop[-1].type.t & ~VT_BTYPE) | (VT_BYTE | VT_UNSIGNED);
        }

        r = adjust_bf(vtop - 1, bit_pos, bit_size);
        if (r == VT_STRUCT) {
            gen_cast_s((ft & VT_BTYPE) == VT_LLONG ? VT_LLONG : VT_INT);
            store_packed_bf(bit_pos, bit_size);
        } else {
            unsigned long long mask = (1ULL << bit_size) - 1;
            if ((ft & VT_BTYPE) != VT_BOOL) {
                /* mask source */
                if ((vtop[-1].type.t & VT_BTYPE) == VT_LLONG)
                    vpushll(mask);
                else
                    vpushi((unsigned)mask);
                gen_op('&');
            }
            /* shift source */
            vpushi(bit_pos);
            gen_op(TOK_SHL);
            vswap();
            /* duplicate destination */
            vdup();
            vrott(3);
            /* load destination, mask and or with source */
            if ((vtop->type.t & VT_BTYPE) == VT_LLONG)
                vpushll(~(mask << bit_pos));
            else
                vpushi(~((unsigned)mask << bit_pos));
            gen_op('&');
            gen_op('|');
            /* store result */
            vstore();
            /* ... and discard */
            vpop();
        }
    } else if (dbt == VT_VOID) {
        --vtop;
    } else {
#ifdef CONFIG_TCC_BCHECK
            /* bound check case */
            if (vtop[-1].r & VT_MUSTBOUND) {
                vswap();
                gbound();
                vswap();
            }
#endif
            rc = RC_INT;
            if (is_float(ft)) {
                rc = RC_FLOAT;
#ifdef TCC_TARGET_X86_64
                if ((ft & VT_BTYPE) == VT_LDOUBLE) {
                    rc = RC_ST0;
                } else if ((ft & VT_BTYPE) == VT_QFLOAT) {
                    rc = RC_FRET;
                }
#endif
            }
            r = gv(rc);  /* generate value */
            /* if lvalue was saved on stack, must read it */
            if ((vtop[-1].r & VT_VALMASK) == VT_LLOCAL) {
                SValue sv;
                t = get_reg(RC_INT);
#if PTR_SIZE == 8
                sv.type.t = VT_PTR;
#else
                sv.type.t = VT_INT;
#endif
                sv.r = VT_LOCAL | VT_LVAL;
                sv.c.i = vtop[-1].c.i;
                load(t, &sv);
                vtop[-1].r = t | VT_LVAL;
            }
            /* two word case handling : store second register at word + 4 (or +8 for x86-64)  */
#if PTR_SIZE == 8
            if (((ft & VT_BTYPE) == VT_QLONG) || ((ft & VT_BTYPE) == VT_QFLOAT)) {
                int addr_type = VT_LLONG, load_size = 8, load_type = ((vtop->type.t & VT_BTYPE) == VT_QLONG) ? VT_LLONG : VT_DOUBLE;
#else
            if ((ft & VT_BTYPE) == VT_LLONG) {
                int addr_type = VT_INT, load_size = 4, load_type = VT_INT;
#endif
                vtop[-1].type.t = load_type;
                store(r, vtop - 1);
                vswap();
                /* convert to int to increment easily */
                vtop->type.t = addr_type;
                gaddrof();
                vpushi(load_size);
                gen_op('+');
                vtop->r |= VT_LVAL;
                vswap();
                vtop[-1].type.t = load_type;
                /* XXX: it works because r2 is spilled last ! */
                store(vtop->r2, vtop - 1);
            } else {
                store(r, vtop - 1);
            }

        vswap();
        vtop--; /* NOT vpop() because on x86 it would flush the fp stack */
        vtop->r |= delayed_cast;
    }
}

/* post defines POST/PRE add. c is the token ++ or -- */
ST_FUNC void inc(int post, int c)
{
    test_lvalue();
    vdup(); /* save lvalue */
    if (post) {
        gv_dup(); /* duplicate value */
        vrotb(3);
        vrotb(3);
    }
    /* add constant */
    vpushi(c - TOK_MID); 
    gen_op('+');
    vstore(); /* store value */
    if (post)
        vpop(); /* if post op, return saved value */
}

ST_FUNC void parse_mult_str (CString *astr, const char *msg)
{
    /* read the string */
    if (tok != TOK_STR)
        expect(msg);
    cstr_new(astr);
    while (tok == TOK_STR) {
        /* XXX: add \0 handling too ? */
        cstr_cat(astr, tokc.str.data, -1);
        next();
    }
    cstr_ccat(astr, '\0');
}

/* If I is >= 1 and a power of two, returns log2(i)+1.
   If I is 0 returns 0.  */
static int exact_log2p1(int i)
{
  int ret;
  if (!i)
    return 0;
  for (ret = 1; i >= 1 << 8; ret += 8)
    i >>= 8;
  if (i >= 1 << 4)
    ret += 4, i >>= 4;
  if (i >= 1 << 2)
    ret += 2, i >>= 2;
  if (i >= 1 << 1)
    ret++;
  return ret;
}

/* Parse __attribute__((...)) GNUC extension. */
static void parse_attribute(AttributeDef *ad)
{
    int t, n;
    CString astr;
    
redo:
    if (tok != TOK_ATTRIBUTE1 && tok != TOK_ATTRIBUTE2)
        return;
    next();
    skip('(');
    skip('(');
    while (tok != ')') {
        if (tok < TOK_IDENT)
            expect("attribute name");
        t = tok;
        next();
        switch(t) {
        case TOK_CLEANUP1:
        case TOK_CLEANUP2:
        {
            Sym *s;

            skip('(');
            s = sym_find(tok);
            if (!s) {
              tcc_warning("implicit declaration of function '%s'",
                          get_tok_str(tok, &tokc));
              s = external_global_sym(tok, &func_old_type);
            }
            ad->cleanup_func = s;
            next();
            skip(')');
            break;
        }
        case TOK_SECTION1:
        case TOK_SECTION2:
            skip('(');
            parse_mult_str(&astr, "section name");
            ad->section = find_section(tcc_state, (char *)astr.data);
            skip(')');
            cstr_free(&astr);
            break;
        case TOK_ALIAS1:
        case TOK_ALIAS2:
            skip('(');
            parse_mult_str(&astr, "alias(\"target\")");
            ad->alias_target = /* save string as token, for later */
              tok_alloc((char*)astr.data, astr.size-1)->tok;
            skip(')');
            cstr_free(&astr);
            break;
        case TOK_VISIBILITY1:
        case TOK_VISIBILITY2:
            skip('(');
            parse_mult_str(&astr,
                           "visibility(\"default|hidden|internal|protected\")");
            if (!strcmp (astr.data, "default"))
                ad->a.visibility = STV_DEFAULT;
            else if (!strcmp (astr.data, "hidden"))
                ad->a.visibility = STV_HIDDEN;
            else if (!strcmp (astr.data, "internal"))
                ad->a.visibility = STV_INTERNAL;
            else if (!strcmp (astr.data, "protected"))
                ad->a.visibility = STV_PROTECTED;
            else
                expect("visibility(\"default|hidden|internal|protected\")");
            skip(')');
            cstr_free(&astr);
            break;
        case TOK_ALIGNED1:
        case TOK_ALIGNED2:
            if (tok == '(') {
                next();
                n = expr_const();
                if (n <= 0 || (n & (n - 1)) != 0) 
                    tcc_error("alignment must be a positive power of two");
                skip(')');
            } else {
                n = MAX_ALIGN;
            }
            ad->a.aligned = exact_log2p1(n);
            if (n != 1 << (ad->a.aligned - 1))
              tcc_error("alignment of %d is larger than implemented", n);
            break;
        case TOK_PACKED1:
        case TOK_PACKED2:
            ad->a.packed = 1;
            break;
        case TOK_WEAK1:
        case TOK_WEAK2:
            ad->a.weak = 1;
            break;
        case TOK_UNUSED1:
        case TOK_UNUSED2:
            /* currently, no need to handle it because tcc does not
               track unused objects */
            break;
        case TOK_NORETURN1:
        case TOK_NORETURN2:
            /* currently, no need to handle it because tcc does not
               track unused objects */
            break;
        case TOK_CDECL1:
        case TOK_CDECL2:
        case TOK_CDECL3:
            ad->f.func_call = FUNC_CDECL;
            break;
        case TOK_STDCALL1:
        case TOK_STDCALL2:
        case TOK_STDCALL3:
            ad->f.func_call = FUNC_STDCALL;
            break;
#ifdef TCC_TARGET_I386
        case TOK_REGPARM1:
        case TOK_REGPARM2:
            skip('(');
            n = expr_const();
            if (n > 3) 
                n = 3;
            else if (n < 0)
                n = 0;
            if (n > 0)
                ad->f.func_call = FUNC_FASTCALL1 + n - 1;
            skip(')');
            break;
        case TOK_FASTCALL1:
        case TOK_FASTCALL2:
        case TOK_FASTCALL3:
            ad->f.func_call = FUNC_FASTCALLW;
            break;            
#endif
        case TOK_MODE:
            skip('(');
            switch(tok) {
                case TOK_MODE_DI:
                    ad->attr_mode = VT_LLONG + 1;
                    break;
                case TOK_MODE_QI:
                    ad->attr_mode = VT_BYTE + 1;
                    break;
                case TOK_MODE_HI:
                    ad->attr_mode = VT_SHORT + 1;
                    break;
                case TOK_MODE_SI:
                case TOK_MODE_word:
                    ad->attr_mode = VT_INT + 1;
                    break;
                default:
                    tcc_warning("__mode__(%s) not supported\n", get_tok_str(tok, NULL));
                    break;
            }
            next();
            skip(')');
            break;
        case TOK_DLLEXPORT:
            ad->a.dllexport = 1;
            break;
        case TOK_NODECORATE:
            ad->a.nodecorate = 1;
            break;
        case TOK_DLLIMPORT:
            ad->a.dllimport = 1;
            break;
        default:
            if (tcc_state->warn_unsupported)
                tcc_warning("'%s' attribute ignored", get_tok_str(t, NULL));
            /* skip parameters */
            if (tok == '(') {
                int parenthesis = 0;
                do {
                    if (tok == '(') 
                        parenthesis++;
                    else if (tok == ')') 
                        parenthesis--;
                    next();
                } while (parenthesis && tok != -1);
            }
            break;
        }
        if (tok != ',')
            break;
        next();
    }
    skip(')');
    skip(')');
    goto redo;
}

static Sym * find_field (CType *type, int v, int *cumofs)
{
    Sym *s = type->ref;
    v |= SYM_FIELD;
    while ((s = s->next) != NULL) {
        if ((s->v & SYM_FIELD) &&
            (s->type.t & VT_BTYPE) == VT_STRUCT &&
            (s->v & ~SYM_FIELD) >= SYM_FIRST_ANOM) {
            Sym *ret = find_field (&s->type, v, cumofs);
            if (ret) {
                *cumofs += s->c;
                return ret;
            }
        }
        if (s->v == v)
          break;
    }
    return s;
}

static void struct_layout(CType *type, AttributeDef *ad)
{
    int size, align, maxalign, offset, c, bit_pos, bit_size;
    int packed, a, bt, prevbt, prev_bit_size;
    int pcc = !tcc_state->ms_bitfields;
    int pragma_pack = *tcc_state->pack_stack_ptr;
    Sym *f;

    maxalign = 1;
    offset = 0;
    c = 0;
    bit_pos = 0;
    prevbt = VT_STRUCT; /* make it never match */
    prev_bit_size = 0;

//#define BF_DEBUG

    for (f = type->ref->next; f; f = f->next) {
        if (f->type.t & VT_BITFIELD)
            bit_size = BIT_SIZE(f->type.t);
        else
            bit_size = -1;
        size = type_size(&f->type, &align);
        a = f->a.aligned ? 1 << (f->a.aligned - 1) : 0;
        packed = 0;

        if (pcc && bit_size == 0) {
            /* in pcc mode, packing does not affect zero-width bitfields */

        } else {
            /* in pcc mode, attribute packed overrides if set. */
            if (pcc && (f->a.packed || ad->a.packed))
                align = packed = 1;

            /* pragma pack overrides align if lesser and packs bitfields always */
            if (pragma_pack) {
                packed = 1;
                if (pragma_pack < align)
                    align = pragma_pack;
                /* in pcc mode pragma pack also overrides individual align */
                if (pcc && pragma_pack < a)
                    a = 0;
            }
        }
        /* some individual align was specified */
        if (a)
            align = a;

        if (type->ref->type.t == VT_UNION) {
            if (pcc && bit_size >= 0)
                size = (bit_size + 7) >> 3;
            offset = 0;
            if (size > c)
                c = size;

        } else if (bit_size < 0) {
            if (pcc)
                c += (bit_pos + 7) >> 3;
            c = (c + align - 1) & -align;
            offset = c;
            if (size > 0)
                c += size;
            bit_pos = 0;
            prevbt = VT_STRUCT;
            prev_bit_size = 0;

        } else {
            /* A bit-field.  Layout is more complicated.  There are two
               options: PCC (GCC) compatible and MS compatible */
            if (pcc) {
                /* In PCC layout a bit-field is placed adjacent to the
                   preceding bit-fields, except if:
                   - it has zero-width
                   - an individual alignment was given
                   - it would overflow its base type container and
                     there is no packing */
                if (bit_size == 0) {
            new_field:
                    c = (c + ((bit_pos + 7) >> 3) + align - 1) & -align;
                    bit_pos = 0;
                } else if (f->a.aligned) {
                    goto new_field;
                } else if (!packed) {
                    int a8 = align * 8;
                    int ofs = ((c * 8 + bit_pos) % a8 + bit_size + a8 - 1) / a8;
                    if (ofs > size / align)
                        goto new_field;
                }

                /* in pcc mode, long long bitfields have type int if they fit */
                if (size == 8 && bit_size <= 32)
                    f->type.t = (f->type.t & ~VT_BTYPE) | VT_INT, size = 4;

                while (bit_pos >= align * 8)
                    c += align, bit_pos -= align * 8;
                offset = c;

                /* In PCC layout named bit-fields influence the alignment
                   of the containing struct using the base types alignment,
                   except for packed fields (which here have correct align).  */
                if (f->v & SYM_FIRST_ANOM
                    // && bit_size // ??? gcc on ARM/rpi does that
                    )
                    align = 1;

            } else {
                bt = f->type.t & VT_BTYPE;
                if ((bit_pos + bit_size > size * 8)
                    || (bit_size > 0) == (bt != prevbt)
                    ) {
                    c = (c + align - 1) & -align;
                    offset = c;
                    bit_pos = 0;
                    /* In MS bitfield mode a bit-field run always uses
                       at least as many bits as the underlying type.
                       To start a new run it's also required that this
                       or the last bit-field had non-zero width.  */
                    if (bit_size || prev_bit_size)
                        c += size;
                }
                /* In MS layout the records alignment is normally
                   influenced by the field, except for a zero-width
                   field at the start of a run (but by further zero-width
                   fields it is again).  */
                if (bit_size == 0 && prevbt != bt)
                    align = 1;
                prevbt = bt;
                prev_bit_size = bit_size;
            }

            f->type.t = (f->type.t & ~(0x3f << VT_STRUCT_SHIFT))
                        | (bit_pos << VT_STRUCT_SHIFT);
            bit_pos += bit_size;
        }
        if (align > maxalign)
            maxalign = align;

#ifdef BF_DEBUG
        printf("set field %s offset %-2d size %-2d align %-2d",
               get_tok_str(f->v & ~SYM_FIELD, NULL), offset, size, align);
        if (f->type.t & VT_BITFIELD) {
            printf(" pos %-2d bits %-2d",
                    BIT_POS(f->type.t),
                    BIT_SIZE(f->type.t)
                    );
        }
        printf("\n");
#endif

        f->c = offset;
        f->r = 0;
    }

    if (pcc)
        c += (bit_pos + 7) >> 3;

    /* store size and alignment */
    a = bt = ad->a.aligned ? 1 << (ad->a.aligned - 1) : 1;
    if (a < maxalign)
        a = maxalign;
    type->ref->r = a;
    if (pragma_pack && pragma_pack < maxalign && 0 == pcc) {
        /* can happen if individual align for some member was given.  In
           this case MSVC ignores maxalign when aligning the size */
        a = pragma_pack;
        if (a < bt)
            a = bt;
    }
    c = (c + a - 1) & -a;
    type->ref->c = c;

#ifdef BF_DEBUG
    printf("struct size %-2d align %-2d\n\n", c, a), fflush(stdout);
#endif

    /* check whether we can access bitfields by their type */
    for (f = type->ref->next; f; f = f->next) {
        int s, px, cx, c0;
        CType t;

        if (0 == (f->type.t & VT_BITFIELD))
            continue;
        f->type.ref = f;
        f->auxtype = -1;
        bit_size = BIT_SIZE(f->type.t);
        if (bit_size == 0)
            continue;
        bit_pos = BIT_POS(f->type.t);
        size = type_size(&f->type, &align);
        if (bit_pos + bit_size <= size * 8 && f->c + size <= c)
            continue;

        /* try to access the field using a different type */
        c0 = -1, s = align = 1;
        for (;;) {
            px = f->c * 8 + bit_pos;
            cx = (px >> 3) & -align;
            px = px - (cx << 3);
            if (c0 == cx)
                break;
            s = (px + bit_size + 7) >> 3;
            if (s > 4) {
                t.t = VT_LLONG;
            } else if (s > 2) {
                t.t = VT_INT;
            } else if (s > 1) {
                t.t = VT_SHORT;
            } else {
                t.t = VT_BYTE;
            }
            s = type_size(&t, &align);
            c0 = cx;
        }

        if (px + bit_size <= s * 8 && cx + s <= c) {
            /* update offset and bit position */
            f->c = cx;
            bit_pos = px;
            f->type.t = (f->type.t & ~(0x3f << VT_STRUCT_SHIFT))
                        | (bit_pos << VT_STRUCT_SHIFT);
            if (s != size)
                f->auxtype = t.t;
#ifdef BF_DEBUG
            printf("FIX field %s offset %-2d size %-2d align %-2d "
                "pos %-2d bits %-2d\n",
                get_tok_str(f->v & ~SYM_FIELD, NULL),
                cx, s, align, px, bit_size);
#endif
        } else {
            /* fall back to load/store single-byte wise */
            f->auxtype = VT_STRUCT;
#ifdef BF_DEBUG
            printf("FIX field %s : load byte-wise\n",
                 get_tok_str(f->v & ~SYM_FIELD, NULL));
#endif
        }
    }
}

/* enum/struct/union declaration. u is VT_ENUM/VT_STRUCT/VT_UNION */
static void struct_decl(CType *type, int u)
{
    int v, c, size, align, flexible;
    int bit_size, bsize, bt;
    Sym *s, *ss, **ps;
    AttributeDef ad, ad1;
    CType type1, btype;

    memset(&ad, 0, sizeof ad);
    next();
    parse_attribute(&ad);
    if (tok != '{') {
        v = tok;
        next();
        /* struct already defined ? return it */
        if (v < TOK_IDENT)
            expect("struct/union/enum name");
        s = struct_find(v);
        if (s && (s->sym_scope == local_scope || tok != '{')) {
            if (u == s->type.t)
                goto do_decl;
            if (u == VT_ENUM && IS_ENUM(s->type.t))
                goto do_decl;
            tcc_error("redefinition of '%s'", get_tok_str(v, NULL));
        }
    } else {
        v = anon_sym++;
    }
    /* Record the original enum/struct/union token.  */
    type1.t = u == VT_ENUM ? u | VT_INT | VT_UNSIGNED : u;
    type1.ref = NULL;
    /* we put an undefined size for struct/union */
    s = sym_push(v | SYM_STRUCT, &type1, 0, -1);
    s->r = 0; /* default alignment is zero as gcc */
do_decl:
    type->t = s->type.t;
    type->ref = s;

    if (tok == '{') {
        next();
        if (s->c != -1)
            tcc_error("struct/union/enum already defined");
        s->c = -2;
        /* cannot be empty */
        /* non empty enums are not allowed */
        ps = &s->next;
        if (u == VT_ENUM) {
            long long ll = 0, pl = 0, nl = 0;
            CType t;
            t.ref = s;
            /* enum symbols have static storage */
            t.t = VT_INT|VT_STATIC|VT_ENUM_VAL;
            for(;;) {
                v = tok;
                if (v < TOK_UIDENT)
                    expect("identifier");
                ss = sym_find(v);
                if (ss && !local_stack)
                    tcc_error("redefinition of enumerator '%s'",
                              get_tok_str(v, NULL));
                next();
                if (tok == '=') {
                    next();
                    ll = expr_const64();
                }
                ss = sym_push(v, &t, VT_CONST, 0);
                ss->enum_val = ll;
                *ps = ss, ps = &ss->next;
                if (ll < nl)
                    nl = ll;
                if (ll > pl)
                    pl = ll;
                if (tok != ',')
                    break;
                next();
                ll++;
                /* NOTE: we accept a trailing comma */
                if (tok == '}')
                    break;
            }
            skip('}');
            /* set integral type of the enum */
            t.t = VT_INT;
            if (nl >= 0) {
                if (pl != (unsigned)pl)
                    t.t = (LONG_SIZE==8 ? VT_LLONG|VT_LONG : VT_LLONG);
                t.t |= VT_UNSIGNED;
            } else if (pl != (int)pl || nl != (int)nl)
                t.t = (LONG_SIZE==8 ? VT_LLONG|VT_LONG : VT_LLONG);
            s->type.t = type->t = t.t | VT_ENUM;
            s->c = 0;
            /* set type for enum members */
            for (ss = s->next; ss; ss = ss->next) {
                ll = ss->enum_val;
                if (ll == (int)ll) /* default is int if it fits */
                    continue;
                if (t.t & VT_UNSIGNED) {
                    ss->type.t |= VT_UNSIGNED;
                    if (ll == (unsigned)ll)
                        continue;
                }
                ss->type.t = (ss->type.t & ~VT_BTYPE)
                    | (LONG_SIZE==8 ? VT_LLONG|VT_LONG : VT_LLONG);
            }
        } else {
            c = 0;
            flexible = 0;
            while (tok != '}') {
                if (!parse_btype(&btype, &ad1)) {
                    skip(';');
                    continue;
                }
                while (1) {
                    if (flexible)
                        tcc_error("flexible array member '%s' not at the end of struct",
                              get_tok_str(v, NULL));