tinycc/tcc.c

/*
 *  TCC - Tiny C Compiler
 * 
 *  Copyright (c) 2001 Fabrice Bellard
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <tcclib.h>

//#define DEBUG
/* preprocessor debug */
//#define PP_DEBUG

/* these sizes are dummy for unix, because malloc() does not use
   memory when the pages are not used */
#define TEXT_SIZE           (4*1024*1024)
#define DATA_SIZE           (4*1024*1024)

#define INCLUDE_STACK_SIZE  32
#define IFDEF_STACK_SIZE    64
#define VSTACK_SIZE         64
#define STRING_MAX_SIZE     1024
#define INCLUDE_PATHS_MAX   32

#define TOK_HASH_SIZE       521
#define TOK_ALLOC_INCR      256 /* must be a power of two */
#define SYM_HASH_SIZE       263

/* number of available temporary registers */
#define NB_REGS             3
/* return register for functions */
#define FUNC_RET_REG        0 
/* defined if function parameters must be evaluated in reverse order */
#define INVERT_FUNC_PARAMS
/* defined if structures are passed as pointers. Otherwise structures
   are directly pushed on stack. */
//#define FUNC_STRUCT_PARAM_AS_PTR

/* token symbol management */
typedef struct TokenSym {
    struct TokenSym *hash_next;
    int tok; /* token number */
    int len;
    char str[1];
} TokenSym;

/* symbol management */
typedef struct Sym {
    int v;    /* symbol token */
    int t;    /* associated type */
    int c;    /* associated number */
    struct Sym *next; /* next related symbol */
    struct Sym *prev; /* prev symbol in stack */
    struct Sym *hash_next; /* next symbol in hash table */
} Sym;

typedef struct SymStack {
  struct Sym *top;
  struct Sym *hash[SYM_HASH_SIZE];
} SymStack;

/* relocation entry (currently only used for functions or variables */
typedef struct Reloc {
    int type;            /* type of relocation */
    int addr;            /* address of relocation */
    struct Reloc *next;  /* next relocation */
} Reloc;

#define RELOC_ADDR32 1  /* 32 bits relocation */
#define RELOC_REL32  2  /* 32 bits relative relocation */


#define SYM_STRUCT 0x40000000 /* struct/union/enum symbol space */
#define SYM_FIELD  0x20000000 /* struct/union field symbol space */

#define FUNC_NEW       1 /* ansi function prototype */
#define FUNC_OLD       2 /* old function prototype */
#define FUNC_ELLIPSIS  3 /* ansi function prototype with ... */

/* field 'Sym.t' for macros */
#define MACRO_OBJ      0 /* object like macro */
#define MACRO_FUNC     1 /* function like macro */

/* type_decl() types */
#define TYPE_ABSTRACT  1 /* type without variable */
#define TYPE_DIRECT    2 /* type with variable */

typedef struct {
    FILE *file;
    char *filename;
    int line_num;
} IncludeFile;

/* loc : local variable index
   glo : global variable index
   ind : output code ptr
   rsym: return symbol
   prog: output code
   anon_sym: anonymous symbol index
*/
FILE *file;
int tok, tokc, tok1, tok1c, rsym, anon_sym,
    prog, ind, loc, glo, vt, vc, const_wanted, line_num;
int global_expr; /* true if compound literals must be allocated
                    globally (used during initializers parsing */
int func_vt, func_vc; /* current function return type (used by
                         return instruction) */
int tok_ident;
TokenSym **table_ident;
TokenSym *hash_ident[521];
char token_buf[STRING_MAX_SIZE + 1];
char *filename, *funcname;
SymStack define_stack, global_stack, local_stack, label_stack;

int vstack[VSTACK_SIZE], *vstack_ptr;
int *macro_ptr, *macro_ptr_allocated;
IncludeFile include_stack[INCLUDE_STACK_SIZE], *include_stack_ptr;
int ifdef_stack[IFDEF_STACK_SIZE], *ifdef_stack_ptr;
char *include_paths[INCLUDE_PATHS_MAX];
int nb_include_paths;

/* use GNU C extensions */
int gnu_ext = 1;

/* The current value can be: */
#define VT_VALMASK 0x000f
#define VT_CONST   0x000a  /* constant in vc 
                              (must be first non register value) */
#define VT_LLOCAL  0x000b  /* lvalue, offset on stack */
#define VT_LOCAL   0x000c  /* offset on stack */
#define VT_CMP     0x000d  /* the value is stored in processor flags (in vc) */
#define VT_JMP     0x000e  /* value is the consequence of jmp true */
#define VT_JMPI    0x000f  /* value is the consequence of jmp false */
#define VT_LVAL    0x0010  /* var is an lvalue */
#define VT_LVALN   -17         /* ~VT_LVAL */
#define VT_FORWARD 0x0020  /* value is forward reference 
                              (only used for functions) */

/* types */
#define VT_INT      0
#define VT_VOID     0x00040
#define VT_BYTE     0x00080  /* signed byte type */
#define VT_PTR      0x00100  /* pointer increment */
#define VT_UNSIGNED 0x00200  /* unsigned type */
#define VT_ARRAY    0x00400  /* array type (only used in parsing) */
#define VT_ENUM     0x00800  /* enum definition */
#define VT_FUNC     0x01000  /* function type */
#define VT_STRUCT  0x002000  /* struct/union definition */
#define VT_SHORT   0x004000  /* short type */
#define VT_STRUCT_SHIFT 18   /* structure/enum name shift (14 bits left) */

/* storage */
#define VT_EXTERN  0x00008000  /* extern definition */
#define VT_STATIC  0x00010000  /* static variable */
#define VT_TYPEDEF 0x00020000  /* typedef definition */

#define VT_TYPE    0xfffc7fc0  /* type mask */
#define VT_TYPEN   0x0000003f  /* ~VT_TYPE */
#define VT_FUNCN   -4097       /* ~VT_FUNC */

/* token values */

/* warning: the following compare tokens depend on i386 asm code */
#define TOK_ULT 0x92
#define TOK_UGE 0x93
#define TOK_EQ  0x94
#define TOK_NE  0x95
#define TOK_ULE 0x96
#define TOK_UGT 0x97
#define TOK_LT  0x9c
#define TOK_GE  0x9d
#define TOK_LE  0x9e
#define TOK_GT  0x9f

#define TOK_LAND  0xa0
#define TOK_LOR   0xa1

#define TOK_DEC   0xa2
#define TOK_MID   0xa3 /* inc/dec, to void constant */
#define TOK_INC   0xa4
#define TOK_ARROW 0xa7 
#define TOK_DOTS  0xa8 /* three dots */
#define TOK_SHR   0xa9 /* unsigned shift right */
#define TOK_UDIV  0xb0 /* unsigned division */
#define TOK_UMOD  0xb1 /* unsigned modulo */
#define TOK_PDIV  0xb2 /* fast division with undefined rounding for pointers */
#define TOK_NUM   0xb3 /* number in tokc */
#define TOK_CCHAR 0xb4 /* char constant in tokc */
#define TOK_STR   0xb5 /* pointer to string in tokc */
#define TOK_TWOSHARPS 0xb6 /* ## preprocessing token */
#define TOK_LCHAR 0xb7
#define TOK_LSTR  0xb8
 
#define TOK_SHL   0x01 /* shift left */
#define TOK_SAR   0x02 /* signed shift right */
  
/* assignement operators : normal operator or 0x80 */
#define TOK_A_MOD 0xa5
#define TOK_A_AND 0xa6
#define TOK_A_MUL 0xaa
#define TOK_A_ADD 0xab
#define TOK_A_SUB 0xad
#define TOK_A_DIV 0xaf
#define TOK_A_XOR 0xde
#define TOK_A_OR  0xfc
#define TOK_A_SHL 0x81
#define TOK_A_SAR 0x82

/* all identificators and strings have token above that */
#define TOK_IDENT 256

enum {
    TOK_INT = TOK_IDENT,
    TOK_VOID,
    TOK_CHAR,
    TOK_IF,
    TOK_ELSE,
    TOK_WHILE,
    TOK_BREAK,
    TOK_RETURN,
    TOK_FOR,
    TOK_EXTERN,
    TOK_STATIC,
    TOK_UNSIGNED,
    TOK_GOTO,
    TOK_DO,
    TOK_CONTINUE,
    TOK_SWITCH,
    TOK_CASE,

    /* ignored types Must have contiguous values */
    TOK_CONST,
    TOK_VOLATILE,
    TOK_LONG,
    TOK_REGISTER,
    TOK_SIGNED,
    TOK_AUTO,
    TOK_INLINE,
    TOK_RESTRICT,

    /* unsupported type */
    TOK_FLOAT,
    TOK_DOUBLE,

    TOK_SHORT,
    TOK_STRUCT,
    TOK_UNION,
    TOK_TYPEDEF,
    TOK_DEFAULT,
    TOK_ENUM,
    TOK_SIZEOF,

    /* preprocessor only */
    TOK_UIDENT, /* first "user" ident (not keyword) */
    TOK_DEFINE = TOK_UIDENT,
    TOK_INCLUDE,
    TOK_IFDEF,
    TOK_IFNDEF,
    TOK_ELIF,
    TOK_ENDIF,
    TOK_DEFINED,
    TOK_UNDEF,
    TOK_ERROR,
    TOK_LINE,
    TOK___LINE__,
    TOK___FILE__,
    TOK___DATE__,
    TOK___TIME__,
    TOK___VA_ARGS__,

    /* special identifiers */
    TOK___FUNC__,
    TOK_MAIN,
};

void sum();
void next(void);
void next_nomacro();
int expr_const();
void expr_eq();
void expr(void);
void decl(int l);
void decl_initializer(int t, int c, int first, int size_only);
int decl_initializer_alloc(int t, int has_init);
int gv(void);
void move_reg();
void save_reg();
void vpush(void);
int get_reg(void);
void macro_subst(int **tok_str, int *tok_len, 
                 Sym **nested_list, int *macro_str);
int save_reg_forced(int r);
void vstore(void);
int type_size(int t, int *a);
int pointed_type(int t);
int pointed_size(int t);
int ist(void);
int type_decl(int *v, int t, int td);

#ifdef PROFILE
/* dummy function for profiling */
void *dlopen(const char *filename, int flag)
{
    return (void *)1;
}
const char *dlerror(void)
{
    return "error";
}

void *dlsym(void *handle, char *symbol)
{
    return (void *)1;
}

#endif

inline int isid(c)
{
    return (c >= 'a' && c <= 'z') ||
        (c >= 'A' && c <= 'Z') ||
        c == '_';
}

inline int isnum(c)
{
    return c >= '0' & c <= '9';
}

void printline()
{
    IncludeFile *f;
    for(f = include_stack; f < include_stack_ptr; f++)
        fprintf(stderr, "In file included from %s:%d:\n", 
                f->filename, f->line_num);
    fprintf(stderr, "%s:%d: ", filename, line_num);
}

void error(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    printline();
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    exit(1);
    va_end(ap);
}

void expect(const char *msg)
{
    error("%s expected", msg);
}

void warning(const char *msg)
{
    printline();
    fprintf(stderr, "warning: %s\n", msg);
}

void skip(c)
{
    if (tok != c)
        error("'%c' expected", c);
    next();
}

void test_lvalue()
{
    if (!(vt & VT_LVAL))
        expect("lvalue");
}

TokenSym *tok_alloc(char *str, int len)
{
    TokenSym *ts, **pts, **ptable;
    int h, i;
    
    if (len <= 0)
        len = strlen(str);
    h = 1;
    for(i=0;i<len;i++)
        h = ((h << 8) | (str[i] & 0xff)) % TOK_HASH_SIZE;
    
    pts = &hash_ident[h];
    while (1) {
        ts = *pts;
        if (!ts)
            break;
        if (ts->len == len && !memcmp(ts->str, str, len))
            return ts;
        pts = &(ts->hash_next);
    }
    /* expand token table if needed */
    i = tok_ident - TOK_IDENT;
    if ((i % TOK_ALLOC_INCR) == 0) {
        ptable = realloc(table_ident, (i + TOK_ALLOC_INCR) * sizeof(TokenSym *));
        if (!ptable)
            error("memory full");
        table_ident = ptable;
    }
    ts = malloc(sizeof(TokenSym) + len);
    if (!ts)
        error("memory full");
    table_ident[i] = ts;
    ts->tok = tok_ident++;
    ts->len = len;
    ts->hash_next = NULL;
    memcpy(ts->str, str, len + 1);
    *pts = ts;
    return ts;
}

void add_char(char **pp, int c)
{
    char *p;
    p = *pp;
    if (c == '\'' || c == '\"' || c == '\\') {
        /* XXX: could be more precise if char or string */
        *p++ = '\\';
    }
    if (c >= 32 && c <= 126) {
        *p++ = c;
    } else {
        *p++ = '\\';
        if (c == '\n') {
            *p++ = 'n';
        } else {
            *p++ = '0' + ((c >> 6) & 7);
            *p++ = '0' + ((c >> 3) & 7);
            *p++ = '0' + (c & 7);
        }
    }
    *pp = p;
}

/* XXX: buffer overflow */
char *get_tok_str(int v, int c)
{
    static char buf[STRING_MAX_SIZE + 1];
    TokenSym *ts;
    char *p;
    int i;

    if (v == TOK_NUM) {
        sprintf(buf, "%d", c);
        return buf;
    } else if (v == TOK_CCHAR || v == TOK_LCHAR) {
        p = buf;
        *p++ = '\'';
        add_char(&p, c);
        *p++ = '\'';
        *p = '\0';
        return buf;
    } else if (v == TOK_STR || v == TOK_LSTR) {
        ts = (TokenSym *)c;
        p = buf;
        *p++ = '\"';
        for(i=0;i<ts->len;i++)
            add_char(&p, ts->str[i]);
        *p++ = '\"';
        *p = '\0';
        return buf;
    } else if (v < TOK_IDENT) {
        p = buf;
        *p++ = v;
        *p = '\0';
        return buf;
    } else if (v < tok_ident) {
        return table_ident[v - TOK_IDENT]->str;
    } else {
        /* should never happen */
        return NULL;
    }
}

/* push, without hashing */
Sym *sym_push2(Sym **ps, int v, int t, int c)
{
    Sym *s;
    s = malloc(sizeof(Sym));
    if (!s)
        error("memory full");
    s->v = v;
    s->t = t;
    s->c = c;
    s->next = NULL;
    /* 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 */
Sym *sym_find2(Sym *s, int v)
{
    while (s) {
        if (s->v == v)
            return s;
        s = s->prev;
    }
    return NULL;
}

/* find a symbol and return its associated structure. 'st' is the
   symbol stack */
Sym *sym_find1(SymStack *st, int v)
{
    Sym *s;

    s = st->hash[v % SYM_HASH_SIZE];
    while (s) {
        if (s->v == v)
            return s;
        s = s->hash_next;
    }
    return 0;
}

Sym *sym_push1(SymStack *st, int v, int t, int c)
{
    Sym *s, **ps;
    s = sym_push2(&st->top, v, t, c);
    /* add in hash table */
    ps = &st->hash[s->v % SYM_HASH_SIZE];
    s->hash_next = *ps;
    *ps = s;
    return s;
}

/* find a symbol in the right symbol space */
Sym *sym_find(int v)
{
    Sym *s;
    s = sym_find1(&local_stack, v);
    if (!s)
        s = sym_find1(&global_stack, v);
    return s;
}

/* push a given symbol on the symbol stack */
Sym *sym_push(int v, int t, int c)
{
    if (local_stack.top)
        return sym_push1(&local_stack, v, t, c);
    else
        return sym_push1(&global_stack, v, t, c);
}

/* pop symbols until top reaches 'b' */
void sym_pop(SymStack *st, Sym *b)
{
    Sym *s, *ss;

    s = st->top;
    while(s != b) {
        ss = s->prev;
        /* free hash table entry */
        st->hash[s->v % SYM_HASH_SIZE] = s->hash_next;
        free(s);
        s = ss;
    }
    st->top = b;
}

int ch, ch1;

/* read next char from current input file */
void inp()
{
 redo:
    ch1 = fgetc(file);
    if (ch1 == -1) {
        if (include_stack_ptr == include_stack)
            return;
        /* pop include stack */
        fclose(file);
        free(filename);
        include_stack_ptr--;
        file = include_stack_ptr->file;
        filename = include_stack_ptr->filename;
        line_num = include_stack_ptr->line_num;
        goto redo;
    }
    if (ch1 == '\n')
        line_num++;
    //    printf("ch1=%c 0x%x\n", ch1, ch1);
}

/* input with '\\n' handling */
void minp()
{
    redo:
    ch = ch1;
    inp();
    if (ch == '\\' && ch1 == '\n') {
        inp();
        goto redo;
    }
    //printf("ch=%c 0x%x\n", ch, ch);
}

/* same as minp, but also skip comments */
void cinp()
{
    int c;

    if (ch1 == '/') {
        inp();
        if (ch1 == '/') {
            /* single line C++ comments */
            inp();
            while (ch1 != '\n' && ch1 != -1)
                inp();
            inp();
            ch = ' '; /* return space */
        } else if (ch1 == '*') {
            /* C comments */
            inp();
            while (ch1 != -1) {
                c = ch1;
                inp();
                if (c == '*' && ch1 == '/') {
                    inp();
                    ch = ' '; /* return space */
                    break;
                }
            }
        } else {
            ch = '/';
        }
    } else {
        minp();
    }
}

void skip_spaces()
{
    while (ch == ' ' || ch == '\t')
        cinp();
}

/* skip block of text until #else, #elif or #endif. skip also pairs of
   #if/#endif */
void preprocess_skip()
{
    int a;
    a = 0;
    while (1) {
        while (ch != '\n') {
            if (ch == -1)
                expect("#endif");
            cinp();
        }
        cinp();
        skip_spaces();
        if (ch == '#') {
            cinp();
            next_nomacro();
            if (a == 0 && 
                (tok == TOK_ELSE || tok == TOK_ELIF || tok == TOK_ENDIF))
                break;
            if (tok == TOK_IF || tok == TOK_IFDEF || tok == TOK_IFNDEF)
                a++;
            else if (tok == TOK_ENDIF)
                a--;
        }
    }
}

inline int is_long_tok(int t)
{
    return (t == TOK_NUM || 
            t == TOK_CCHAR || t == TOK_LCHAR ||
            t == TOK_STR || t == TOK_LSTR);
}

void tok_add(int **tok_str, int *tok_len, int t)
{
    int len, *str;
    len = *tok_len;
    str = *tok_str;
    if ((len & 63) == 0) {
        str = realloc(str, (len + 64) * sizeof(int));
        if (!str)
            return;
        *tok_str = str;
    }
    str[len++] = t;
    *tok_len = len;
}

void tok_add2(int **tok_str, int *tok_len, int t, int c)
{
    tok_add(tok_str, tok_len, t);
    if (is_long_tok(t))
        tok_add(tok_str, tok_len, c);
}

/* eval an expression for #if/#elif */
int expr_preprocess()
{
    int *str, len, c, t;
    
    str = NULL;
    len = 0;
    while (1) {
        skip_spaces();
        if (ch == '\n')
            break;
        next(); /* do macro subst */
        if (tok == TOK_DEFINED) {
            next_nomacro();
            t = tok;
            if (t == '(') 
                next_nomacro();
            c = sym_find1(&define_stack, tok) != 0;
            if (t == '(')
                next_nomacro();
            tok = TOK_NUM;
            tokc = c;
        } else if (tok >= TOK_IDENT) {
            /* if undefined macro */
            tok = TOK_NUM;
            tokc = 0;
        }
        tok_add2(&str, &len, tok, tokc);
    }
    tok_add(&str, &len, -1); /* simulate end of file */
    tok_add(&str, &len, 0);
    /* now evaluate C constant expression */
    macro_ptr = str;
    next();
    c = expr_const();
    macro_ptr = NULL;
    free(str);
    return c != 0;
}

#ifdef DEBUG
void tok_print(int *str)
{
    int t, c;

    while (1) {
        t = *str++;
        if (!t)
            break;
        c = 0;
        if (is_long_tok(t))
            c = *str++;
        printf(" %s", get_tok_str(t, c));
    }
    printf("\n");
}
#endif

/* XXX: should be more factorized */
void define_symbol(char *sym)
{
    TokenSym *ts;
    int *str, len;

    ts = tok_alloc(sym, 0);
    str = NULL;
    len = 0;
    tok_add2(&str, &len, TOK_NUM, 1);
    tok_add(&str, &len, 0);
    sym_push1(&define_stack, ts->tok, MACRO_OBJ, (int)str);
}

void preprocess()
{
    int size, i, c, v, t, *str, len;
    char buf[1024], *q, *p;
    char buf1[1024];
    FILE *f;
    Sym **ps, *first, *s;

    cinp();
    next_nomacro();
 redo:
    if (tok == TOK_DEFINE) {
        next_nomacro();
        v = tok;
        /* XXX: should check if same macro (ANSI) */
        first = NULL;
        t = MACRO_OBJ;
        /* '(' must be just after macro definition for MACRO_FUNC */
        if (ch == '(') {
            next_nomacro();
            next_nomacro();
            ps = &first;
            while (tok != ')') {
                if (tok == TOK_DOTS) 
                    tok = TOK___VA_ARGS__;
                s = sym_push1(&define_stack, tok | SYM_FIELD, 0, 0);
                *ps = s;
                ps = &s->next;
                next_nomacro();
                if (tok != ',')
                    break;
                next_nomacro();
            }
            t = MACRO_FUNC;
        }
        str = NULL;
        len = 0;
        while (1) {
            skip_spaces();
            if (ch == '\n' || ch == -1)
                break;
            next_nomacro();
            tok_add2(&str, &len, tok, tokc);
        }
        tok_add(&str, &len, 0);
#ifdef PP_DEBUG
        printf("define %s %d: ", get_tok_str(v, 0), t);
        tok_print(str);
#endif
        s = sym_push1(&define_stack, v, t, (int)str);
        s->next = first;
    } else if (tok == TOK_UNDEF) {
        next_nomacro();
        s = sym_find1(&define_stack, tok);
        /* undefine symbol by putting an invalid name */
        if (s)
            s->v = 0;
    } else if (tok == TOK_INCLUDE) {
        skip_spaces();
        if (ch == '<') {
            c = '>';
            goto read_name;
        } else if (ch == '\"') {
            c = ch;
        read_name:
            minp();
            q = buf;
            while (ch != c && ch != '\n' && ch != -1) {
                if ((q - buf) < sizeof(buf) - 1)
                    *q++ = ch;
                minp();
            }
            *q = '\0';
        } else {
            next();
            if (tok != TOK_STR)
                error("#include syntax error");
            /* XXX: buffer overflow */
            strcpy(buf, get_tok_str(tok, tokc));
            c = '\"';
        }
        if (include_stack_ptr >= include_stack + INCLUDE_STACK_SIZE)
            error("memory full");
        if (c == '\"') {
            /* first search in current dir if "header.h" */
            /* XXX: buffer overflow */
            size = 0;
            p = strrchr(filename, '/');
            if (p) 
                size = p + 1 - filename;
            memcpy(buf1, filename, size);
            buf1[size] = '\0';
            strcat(buf1, buf);
            f = fopen(buf1, "r");
            if (f)
                goto found;
        }
        /* now search in standard include path */
        for(i=nb_include_paths - 1;i>=0;i--) {
            strcpy(buf1, include_paths[i]);
            strcat(buf1, "/");
            strcat(buf1, buf);
            f = fopen(buf1, "r");
            if (f)
                goto found;
        }
        error("include file not found");
        f = NULL;
    found:
        /* push current file in stack */
        /* XXX: fix current line init */
        include_stack_ptr->file = file;
        include_stack_ptr->filename = filename;
        include_stack_ptr->line_num = line_num;
        include_stack_ptr++;
        file = f;
        filename = strdup(buf1);
        line_num = 1;
    } else if (tok == TOK_IFNDEF) {
        c = 1;
        goto do_ifdef;
    } else if (tok == TOK_IF) {
        c = expr_preprocess();
        goto do_if;
    } else if (tok == TOK_IFDEF) {
        c = 0;
    do_ifdef:
        next_nomacro();
        c = (sym_find1(&define_stack, tok) != 0) ^ c;
    do_if:
        if (ifdef_stack_ptr >= ifdef_stack + IFDEF_STACK_SIZE)
            error("memory full");
        *ifdef_stack_ptr++ = c;
        goto test_skip;
    } else if (tok == TOK_ELSE) {
        if (ifdef_stack_ptr == ifdef_stack ||
            (ifdef_stack_ptr[-1] & 2))
            error("#else after #else");
        c = (ifdef_stack_ptr[-1] ^= 3);
        goto test_skip;
    } else if (tok == TOK_ELIF) {
        if (ifdef_stack_ptr == ifdef_stack ||
            ifdef_stack_ptr[-1] > 1)
            error("#elif after #else");
        c = expr_preprocess();
        ifdef_stack_ptr[-1] = c;
    test_skip:
        if (!(c & 1)) {
            preprocess_skip();
            goto redo;
        }
    } else if (tok == TOK_ENDIF) {
        if (ifdef_stack_ptr == ifdef_stack)
            expect("#if");
        ifdef_stack_ptr--;
    } else if (tok == TOK_LINE) {
        next();
        if (tok != TOK_NUM)
            error("#line");
        line_num = tokc;
        skip_spaces();
        if (ch != '\n') {
            next();
            if (tok != TOK_STR)
                error("#line");
            /* XXX: potential memory leak */
            filename = strdup(get_tok_str(tok, tokc));
        }
    } else if (tok == TOK_ERROR) {
        error("#error");
    }
    /* ignore other preprocess commands or #! for C scripts */
    while (ch != '\n' && ch != -1)
        cinp();
}

/* read a number in base b */
int getn(b)
{
    int n, t;
    n = 0;
    while (1) {
        if (ch >= 'a' & ch <= 'f')
            t = ch - 'a' + 10;
        else if (ch >= 'A' & ch <= 'F')
            t = ch - 'A' + 10;
        else if (isnum(ch))
            t = ch - '0';
        else
            break;
        if (t < 0 | t >= b)
            break;
        n = n * b + t;
        cinp();
    }
    return n;
}

/* read a character for string or char constant and eval escape codes */
int getq()
{
    int c;

    c = ch;
    minp();
    if (c == '\\') {
        if (isnum(ch)) {
            /* at most three octal digits */
            c = ch - '0';
            minp();
            if (isnum(ch)) {
                c = c * 8 + ch - '0';
                minp();
                if (isnum(ch)) {
                    c = c * 8 + ch - '0';
                    minp();
                }
            }
            return c;
        } else if (ch == 'x') {
            minp();
            return getn(16);
        } else {
            if (ch == 'a')
                c = '\a';
            else if (ch == 'b')
                c = '\b';
            else if (ch == 'f')
                c = '\f';
            else if (ch == 'n')
                c = '\n';
            else if (ch == 'r')
                c = '\r';
            else if (ch == 't')
                c = '\t';
            else if (ch == 'v')
                c = '\v';
            else
                c = ch;
            minp();
        }
    }
    return c;
}

/* return next token without macro substitution */
void next_nomacro1()
{
    int b;
    char *q;
    TokenSym *ts;

    /* skip spaces */
    while(1) {
        while (ch == '\n') {
            cinp();
            while (ch == ' ' || ch == 9)
                cinp();
            if (ch == '#') {
                /* preprocessor command if # at start of line after
                   spaces */
                preprocess();
            }
        }
        if (ch != ' ' && ch != '\t' && ch != '\f')
            break;
        cinp();
    }
    if (isid(ch)) {
        q = token_buf;
        *q++ = ch;
        cinp();
        if (q[-1] == 'L') {
            /* XXX: not supported entirely (needs different
               preprocessor architecture) */
            if (ch == '\'') {
                tok = TOK_LCHAR;
                goto char_const;
            }
            if (ch == '\"') {
                tok = TOK_LSTR;
                goto str_const;
            }
        }
        while (isid(ch) | isnum(ch)) {
            if (q >= token_buf + STRING_MAX_SIZE)
                error("ident too long");
            *q++ = ch;
            cinp();
        }
        *q = '\0';
        ts = tok_alloc(token_buf, q - token_buf);
        tok = ts->tok;
    } else if (isnum(ch)) {
        /* number */
        b = 10;
        if (ch == '0') {
            cinp();
            b = 8;
            if (ch == 'x' || ch == 'X') {
                cinp();
                b = 16;
            } else if (ch == 'b' || ch == 'B') {
                cinp();
                b = 2;
            }
        }
        tokc = getn(b);
        /* XXX: add unsigned constant support (ANSI) */
        while (ch == 'L' || ch == 'l' || ch == 'U' || ch == 'u')
            cinp();
        tok = TOK_NUM;
    } else if (ch == '\'') {
        tok = TOK_CCHAR;
    char_const:
        minp();
        tokc = getq();
        if (ch != '\'')
            expect("\'");
        minp();
    } else if (ch == '\"') {
        tok = TOK_STR;
    str_const:
        minp();
        q = token_buf;
        while (ch != '\"') {
            b = getq();
            if (ch == -1)
                error("unterminated string");
            if (q >= token_buf + STRING_MAX_SIZE)
                error("string too long");
            *q++ = b;
        }
        *q = '\0';
        tokc = (int)tok_alloc(token_buf, q - token_buf);
        minp();
    } else {
        q = "<=\236>=\235!=\225&&\240||\241++\244--\242==\224<<\1>>\2+=\253-=\255*=\252/=\257%=\245&=\246^=\336|=\374->\247..\250##\266";
        /* two chars */
        tok = ch;
        cinp();
        while (*q) {
            if (*q == tok & q[1] == ch) {
                cinp();
                tok = q[2] & 0xff;
                /* three chars tests */
                if (tok == TOK_SHL | tok == TOK_SAR) {
                    if (ch == '=') {
                        tok = tok | 0x80;
                        cinp();
                    }
                } else if (tok == TOK_DOTS) {
                    if (ch != '.')
                        error("parse error");
                    cinp();
                }
                return;
            }
            q = q + 3;
        }
        /* single char substitutions */
        if (tok == '<')
            tok = TOK_LT;
        else if (tok == '>')
            tok = TOK_GT;
    }
}

/* return next token without macro substitution. Can read input from
   macro_ptr buffer */
void next_nomacro()
{
    if (macro_ptr) {
        tok = *macro_ptr;
        if (tok) {
            macro_ptr++;
            if (is_long_tok(tok))
                tokc = *macro_ptr++;
        }
    } else {
        next_nomacro1();
    }
}

/* substitute args in macro_str and return allocated string */
int *macro_arg_subst(Sym **nested_list, int *macro_str, Sym *args)
{
    int *st, last_tok, t, c, notfirst, *str, len;
    Sym *s;
    TokenSym *ts;

    str = NULL;
    len = 0;
    last_tok = 0;
    while(1) {
        t = *macro_str++;
        if (!t)
            break;
        if (t == '#') {
            /* stringize */
            t = *macro_str++;
            if (!t)
                break;
            s = sym_find2(args, t);
            if (s) {
                token_buf[0] = '\0';
                st = (int *)s->c;
                /* XXX: buffer overflow */
                notfirst = 0;
                while (*st) {
                    if (notfirst)
                        strcat(token_buf, " ");
                    t = *st++;
                    c = 0;
                    if (is_long_tok(t)) 
                        c = *st++;
                    strcat(token_buf, get_tok_str(t, c));
                    notfirst = 1;
                }
#ifdef PP_DEBUG
                printf("stringize: %s\n", token_buf);
#endif
                /* add string */
                ts = tok_alloc(token_buf, 0);
                tok_add2(&str, &len, TOK_STR, (int)ts);
            } else {
                tok_add(&str, &len, t);
            }
        } else if (is_long_tok(t)) {
            tok_add2(&str, &len, t, *macro_str++);
        } else {
            s = sym_find2(args, t);
            if (s) {
                st = (int *)s->c;
                /* if '##' is present before or after , no arg substitution */
                if (*macro_str == TOK_TWOSHARPS || last_tok == TOK_TWOSHARPS) {
                    while (*st)
                        tok_add(&str, &len, *st++);
                } else {
                    macro_subst(&str, &len, nested_list, st);
                }
            } else {
                tok_add(&str, &len, t);
            }
        }
        last_tok = t;
    }
    tok_add(&str, &len, 0);
    return str;
}

/* handle the '##' operator */
int *macro_twosharps(int *macro_str)
{
    TokenSym *ts;
    int *macro_str1, macro_str1_len, *macro_ptr1;
    int t, c;
    char *p;

    macro_str1 = NULL;
    macro_str1_len = 0;
    tok = 0;
    while (1) {
        next_nomacro();
        if (tok == 0)
            break;
        if (*macro_ptr == TOK_TWOSHARPS) {
            macro_ptr++;
            macro_ptr1 = macro_ptr;
            t = *macro_ptr;
            if (t) {
                macro_ptr++;
                c = 0;
                if (is_long_tok(t))
                    c = *macro_ptr++;
                /* XXX: we handle only most common cases: 
                   ident + ident or ident + number */
                if (tok >= TOK_IDENT && 
                    (t >= TOK_IDENT || t == TOK_NUM)) {
                    /* XXX: buffer overflow */
                    p = get_tok_str(tok, tokc);
                    strcpy(token_buf, p);
                    p = get_tok_str(t, c);
                    strcat(token_buf, p);
                    ts = tok_alloc(token_buf, 0);
                    tok_add2(&macro_str1, &macro_str1_len, ts->tok, 0);
                } else {
                    /* cannot merge tokens: skip '##' */
                    macro_ptr = macro_ptr1;
                }
            }
        } else {
            tok_add2(&macro_str1, &macro_str1_len, tok, tokc);
        }
    }
    tok_add(&macro_str1, &macro_str1_len, 0);
    return macro_str1;
}



/* do macro substitution of macro_str and add result to
   (tok_str,tok_len). If macro_str is NULL, then input stream token is
   substituted. 'nested_list' is the list of all macros we got inside
   to avoid recursing. */
void macro_subst(int **tok_str, int *tok_len, 
                 Sym **nested_list, int *macro_str)
{
    Sym *s, *args, *sa, *sa1;
    int *str, parlevel, len, *mstr, t, *saved_macro_ptr;
    int mstr_allocated, *macro_str1;

    saved_macro_ptr = macro_ptr;
    macro_ptr = macro_str;
    macro_str1 = NULL;
    if (macro_str) {
        /* first scan for '##' operator handling */
        macro_str1 = macro_twosharps(macro_str);
        macro_ptr = macro_str1;
    }

    while (1) {
        next_nomacro();
        if (tok == 0)
            break;
        /* special macros */
        if (tok == TOK___LINE__) {
            tok_add2(tok_str, tok_len, TOK_NUM, line_num);
        } else if (tok == TOK___FILE__) {
            tok_add2(tok_str, tok_len, TOK_STR, 
                     (int)tok_alloc(filename, 0));
        } else if (tok == TOK___DATE__) {
            tok_add2(tok_str, tok_len, TOK_STR, 
                     (int)tok_alloc("Jan  1 1970", 0));
        } else if (tok == TOK___TIME__) {
            tok_add2(tok_str, tok_len, TOK_STR, 
                     (int)tok_alloc("00:00:00", 0));
        } else if ((s = sym_find1(&define_stack, tok)) != NULL) {
            /* if symbol is a macro, prepare substitution */
            /* if nested substitution, do nothing */
            if (sym_find2(*nested_list, tok))
                goto no_subst;
            mstr = (int *)s->c;
            mstr_allocated = 0;
            if (s->t == MACRO_FUNC) {
                /* NOTE: we do not use next_nomacro to avoid eating the
                   next token. XXX: find better solution */
                if (macro_ptr) {
                    t = *macro_ptr;
                } else {
                    while (ch == ' ' || ch == '\t' || ch == '\n')
                        cinp();
                    t = ch;
                }
                if (t != '(') /* no macro subst */
                    goto no_subst;
                    
                /* argument macro */
                next_nomacro();
                next_nomacro();
                args = NULL;
                sa = s->next;
                while (tok != ')' && sa) {
                    len = 0;
                    str = NULL;
                    parlevel = 0;
                    while ((parlevel > 0 || 
                            (tok != ')' && 
                             (tok != ',' || 
                              sa->v == (TOK___VA_ARGS__ | SYM_FIELD)))) && 
                           tok != -1) {
                        if (tok == '(')
                            parlevel++;
                        else if (tok == ')')
                            parlevel--;
                        tok_add2(&str, &len, tok, tokc);
                        next_nomacro();
                    }
                    tok_add(&str, &len, 0);
                    sym_push2(&args, sa->v & ~SYM_FIELD, 0, (int)str);
                    if (tok != ',')
                        break;
                    next_nomacro();
                    sa = sa->next;
                }
                if (tok != ')')
                    expect(")");
                /* now subst each arg */
                mstr = macro_arg_subst(nested_list, mstr, args);
                /* free memory */
                sa = args;
                while (sa) {
                    sa1 = sa->prev;
                    free((int *)sa->c);
                    free(sa);
                    sa = sa1;
                }
                mstr_allocated = 1;
            }
            sym_push2(nested_list, s->v, 0, 0);
            macro_subst(tok_str, tok_len, nested_list, mstr);
            /* pop nested defined symbol */
            sa1 = *nested_list;
            *nested_list = sa1->prev;
            free(sa1);
            if (mstr_allocated)
                free(mstr);
        } else {
        no_subst:
            /* no need to add if reading input stream */
            if (!macro_str)
                return;
            tok_add2(tok_str, tok_len, tok, tokc);
        }
        /* only replace one macro while parsing input stream */
        if (!macro_str)
            return;
    }
    macro_ptr = saved_macro_ptr;
    if (macro_str1)
        free(macro_str1);
}

/* return next token with macro substitution */
void next()
{
    int len, *ptr;
    Sym *nested_list;

    /* special 'ungettok' case for label parsing */
    if (tok1) {
        tok = tok1;
        tokc = tok1c;
        tok1 = 0;
    } else {
    redo:
        if (!macro_ptr) {
            /* if not reading from macro substuted string, then try to substitute */
            len = 0;
            ptr = NULL;
            nested_list = NULL;
            macro_subst(&ptr, &len, &nested_list, NULL);
            if (ptr) {
                tok_add(&ptr, &len, 0);
                macro_ptr = ptr;
                macro_ptr_allocated = ptr;
                goto redo;
            }
            if (tok == 0)
                goto redo;
        } else {
            next_nomacro();
            if (tok == 0) {
                /* end of macro string: free it */
                free(macro_ptr_allocated);
                macro_ptr = NULL;
                goto redo;
            }
        }
    }
#ifdef DEBUG
    printf("token = %s\n", get_tok_str(tok, tokc));
#endif
}

void swap(int *p, int *q)
{
    int t;
    t = *p;
    *p = *q;
    *q = t;
}

void vset(t, v)
{
    vt = t;
    vc = v;
}

/******************************************************/
/* X86 code generator */

typedef struct GFuncContext {
    int args_size;
} GFuncContext;

void g(int c)
{
    *(char *)ind++ = c;
}

void o(int c)
{
    while (c) {
        g(c);
        c = c / 256;
    }
}

void gen_le32(int c)
{
    g(c);
    g(c >> 8);
    g(c >> 16);
    g(c >> 24);
}

/* add a new relocation entry to symbol 's' */
void greloc(Sym *s, int addr, int type)
{
    Reloc *p;
    p = malloc(sizeof(Reloc));
    if (!p)
        error("memory full");
    p->type = type;
    p->addr = addr;
    p->next = (Reloc *)s->c;
    s->c = (int)p;
}

/* patch each relocation entry with value 'val' */
void greloc_patch(Sym *s, int val)
{
    Reloc *p, *p1;

    p = (Reloc *)s->c;
    while (p != NULL) {
        p1 = p->next;
        switch(p->type) {
        case RELOC_ADDR32:
            *(int *)p->addr = val;
            break;
        case RELOC_REL32:
            *(int *)p->addr = val - p->addr - 4;
            break;
        }
        free(p);
        p = p1;
    }
    s->c = val;
    s->t &= ~VT_FORWARD;
}

/* output a symbol and patch all calls to it */
void gsym_addr(t, a)
{
    int n;
    while (t) {
        n = *(int *)t; /* next value */
        *(int *)t = a - t - 4;
        t = n;
    }
}

void gsym(t)
{
    gsym_addr(t, ind);
}

/* psym is used to put an instruction with a data field which is a
   reference to a symbol. It is in fact the same as oad ! */
#define psym oad

/* instruction + 4 bytes data. Return the address of the data */
int oad(int c, int s)
{
    o(c);
    *(int *)ind = s;
    s = ind;
    ind = ind + 4;
    return s;
}

/* output constant with relocation if 't & VT_FORWARD' is true */
void gen_addr32(int c, int t)
{
    if (!(t & VT_FORWARD)) {
        gen_le32(c);
    } else {
        greloc((Sym *)c, ind, RELOC_ADDR32);
        gen_le32(0);
    }
}

/* XXX: generate correct pointer for forward references to functions */
/* r = (ft, fc) */
void load(r, ft, fc)
{
    int v, t;

    v = ft & VT_VALMASK;
    if (ft & VT_LVAL) {
        if (v == VT_LLOCAL) {
            load(r, VT_LOCAL | VT_LVAL, fc);
            v = r;
        }
        if ((ft & VT_TYPE) == VT_BYTE)
            o(0xbe0f);   /* movsbl */
        else if ((ft & VT_TYPE) == (VT_BYTE | VT_UNSIGNED))
            o(0xb60f);   /* movzbl */
        else if ((ft & VT_TYPE) == VT_SHORT)
            o(0xbf0f);   /* movswl */
        else if ((ft & VT_TYPE) == (VT_SHORT | VT_UNSIGNED))
            o(0xb70f);   /* movzwl */
        else
            o(0x8b);     /* movl */
        if (v == VT_CONST) {
            o(0x05 + r * 8); /* 0xXX, r */
            gen_addr32(fc, ft);
        } else if (v == VT_LOCAL) {
            oad(0x85 + r * 8, fc); /* xx(%ebp), r */
        } else {
            g(0x00 + r * 8 + v); /* (v), r */
        }
    } else {
        if (v == VT_CONST) {
            o(0xb8 + r); /* mov $xx, r */
            gen_addr32(fc, ft);
        } else if (v == VT_LOCAL) {
            o(0x8d);
            oad(0x85 + r * 8, fc); /* lea xxx(%ebp), r */
        } else if (v == VT_CMP) {
            oad(0xb8 + r, 0); /* mov $0, r */
            o(0x0f); /* setxx %br */
            o(fc);
            o(0xc0 + r);
        } else if (v == VT_JMP || v == VT_JMPI) {
            t = v & 1;
            oad(0xb8 + r, t); /* mov $1, r */
            oad(0xe9, 5); /* jmp after */
            gsym(fc);
            oad(0xb8 + r, t ^ 1); /* mov $0, r */
        } else if (v != r) {
            o(0x89);
            o(0xc0 + r + v * 8); /* mov v, r */
        }
    }
}

/* (ft, fc) = r */
/* WARNING: r must not be allocated on the stack */
void store(r, ft, fc)
{
    int fr, b;

    fr = ft & VT_VALMASK;
    b = (ft & VT_TYPE) == VT_BYTE;
    /* XXX: incorrect if reg to reg */
    if (ft & VT_SHORT)
        o(0x66);
    o(0x89 - b);
    if (fr == VT_CONST) {
        o(0x05 + r * 8); /* mov r,xxx */
        gen_addr32(fc, ft);
    } else if (fr == VT_LOCAL) {
        oad(0x85 + r * 8, fc); /* mov r,xxx(%ebp) */
    } else if (ft & VT_LVAL) {
        g(fr + r * 8); /* mov r, (fr) */
    } else if (fr != r) {
        o(0xc0 + fr + r * 8); /* mov r, fr */
    }
}

/* start function call and return function call context */
void gfunc_start(GFuncContext *c)
{
    c->args_size = 0;
}

/* push function parameter which is in (vt, vc) */
void gfunc_param(GFuncContext *c)
{
    int size, align, ft, fc, r;

    if ((vt & (VT_STRUCT | VT_LVAL)) == (VT_STRUCT | VT_LVAL)) {
        size = type_size(vt, &align);
        /* align to stack align size */
        size = (size + 3) & ~3;
        /* allocate the necessary size on stack */
        oad(0xec81, size); /* sub $xxx, %esp */
        /* generate structure store */
        r = get_reg();
        o(0x89); /* mov %esp, r */
        o(0xe0 + r);
        ft = vt;
        fc = vc;
        vset(VT_INT | r, 0);
        vpush();
        vt = ft;
        vc = fc;
        vstore();
        c->args_size += size;
    } else {
        /* simple type (currently always same size) */
        /* XXX: implicit cast ? */
        r = gv();
        o(0x50 + r); /* push r */
        c->args_size += 4;
    }
}

/* generate function call with address in (ft, fc) and free function */
void gfunc_call(GFuncContext *c, int ft, int fc)
{
    int r;
    r = ft & VT_VALMASK;
    if (r == VT_CONST) {
        /* forward reference */
        if (ft & VT_FORWARD) {
            greloc((Sym *)fc, ind + 1, RELOC_REL32);
            oad(0xe8, 0);
        } else {
            oad(0xe8, fc - ind - 5);
        }
    } else if (r == VT_LOCAL) {
        oad(0x95ff, fc); /* call *xxx(%ebp) */
    } else {
        /* not actually used */
        o(0xff); /* call *r */
        o(0xd0 + r);
    }
    if (c->args_size)
        oad(0xc481, c->args_size); /* add $xxx, %esp */
}

int gjmp(int t)
{
    return psym(0xe9, t);
}

/* generate a test. set 'inv' to invert test */
int gtst(inv, t)
{
    int v, *p;
    v = vt & VT_VALMASK;
    if (v == VT_CMP) {
        /* fast case : can jump directly since flags are set */
        g(0x0f);
        t = psym((vc - 16) ^ inv, t);
    } else if (v == VT_JMP || v == VT_JMPI) {
        /* && or || optimization */
        if ((v & 1) == inv) {
            /* insert vc jump list in t */
            p = &vc;
            while (*p != 0)
                p = (int *)*p;
            *p = t;
            t = vc;
        } else {
            t = gjmp(t);
            gsym(vc);
        }
    } else if ((vt & (VT_VALMASK | VT_LVAL)) == VT_CONST) {
        /* constant jmp optimization */
        if ((vc != 0) != inv) 
            t = gjmp(t);
    } else {
        v = gv();
        o(0x85);
        o(0xc0 + v * 9);
        g(0x0f);
        t = psym(0x85 ^ inv, t);
    }
    return t;
}

/* generate a binary operation 'v = r op fr' instruction and modifies
   (vt,vc) if needed */
void gen_op1(op, r, fr)
{
    int t;
    if (op == '+') {
        o(0x01);
        o(0xc0 + r + fr * 8); 
    } else if (op == '-') {
        o(0x29);
        o(0xc0 + r + fr * 8); 
    } else if (op == '&') {
        o(0x21);
        o(0xc0 + r + fr * 8); 
    } else if (op == '^') {
        o(0x31);
        o(0xc0 + r + fr * 8); 
    } else if (op == '|') {
        o(0x09);
        o(0xc0 + r + fr * 8); 
    } else if (op == '*') {
        o(0xaf0f); /* imul fr, r */
        o(0xc0 + fr + r * 8);
    } else if (op == TOK_SHL | op == TOK_SHR | op == TOK_SAR) {
        /* op2 is %ecx */
        if (fr != 1) {
            if (r == 1) {
                r = fr;
                fr = 1;
                o(0x87); /* xchg r, %ecx */
                o(0xc1 + r * 8);
            } else
                move_reg(1, fr);
        }
        o(0xd3); /* shl/shr/sar %cl, r */
        if (op == TOK_SHL) 
            o(0xe0 + r);
        else if (op == TOK_SHR)
            o(0xe8 + r);
        else
            o(0xf8 + r);
        vt = (vt & VT_TYPE) | r;
    } else if (op == '/' | op == TOK_UDIV | op == TOK_PDIV | 
               op == '%' | op == TOK_UMOD) {
        save_reg(2); /* save edx */
        t = save_reg_forced(fr); /* save fr and get op2 location */
        move_reg(0, r); /* op1 is %eax */
        if (op == TOK_UDIV | op == TOK_UMOD) {
            o(0xf7d231); /* xor %edx, %edx, div t(%ebp), %eax */
            oad(0xb5, t);
        } else {
            o(0xf799); /* cltd, idiv t(%ebp), %eax */
            oad(0xbd, t);
        }
        if (op == '%' | op == TOK_UMOD)
            r = 2;
        else
            r = 0;
        vt = (vt & VT_TYPE) | r;
    } else {
        o(0x39);
        o(0xc0 + r + fr * 8); /* cmp fr, r */
        vset(VT_CMP, op);
    }
}

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

int save_reg_forced(int r)
{
    int i, l, *p, t;
    /* store register */
    loc = (loc - 4) & -3;
    store(r, VT_LOCAL, loc);
    l = loc;

    /* modify all stack values */
    for(p=vstack;p<vstack_ptr;p+=2) {
        i = p[0] & VT_VALMASK;
        if (i == r) {
            if (p[0] & VT_LVAL)
                t = VT_LLOCAL;
            else
                t = VT_LOCAL;
            p[0] = (p[0] & VT_TYPE) | VT_LVAL | t;
            p[1] = l;
        }
    }
    return l;
}

/* save r to memory. and mark it as being free */
void save_reg(r)
{
    int i, *p;

    /* modify all stack values */
    for(p=vstack;p<vstack_ptr;p+=2) {
        i = p[0] & VT_VALMASK;
        if (i == r) {
            save_reg_forced(r);
            break;
        }
    }
}

/* find a free register. If none, save one register */
int get_reg(void)
{
    int r, i, *p;

    /* find a free register */
    for(r=0;r<NB_REGS;r++) {
        for(p=vstack;p<vstack_ptr;p+=2) {
            i = p[0] & VT_VALMASK;
            if (i == 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_op()) */
    for(p=vstack;p<vstack_ptr;p+=2) {
        r = p[0] & VT_VALMASK;
        if (r < VT_CONST) {
            save_reg(r);
            break;
        }
    }
    return r;
}

void save_regs()
{
    int r, *p;
    for(p=vstack;p<vstack_ptr;p+=2) {
        r = p[0] & VT_VALMASK;
        if (r < VT_CONST) {
            save_reg(r);
        }
    }
}

/* move register 's' to 'r', and flush previous value of r to memory
   if needed */
void move_reg(r, s)
{
    if (r != s) {
        save_reg(r);
        load(r, s, 0);
    }
}

/* convert a stack entry in register. lvalues are converted as
   values. Cannot be used if cannot be converted to register value
   (such as structures). */
int gvp(int *p)
{
    int r;
    r = p[0] & VT_VALMASK;
    if (r >= VT_CONST || (p[0] & VT_LVAL))
        r = get_reg();
    /* NOTE: get_reg can modify p[] */
    load(r, p[0], p[1]);
    p[0] = (p[0] & VT_TYPE) | r;
    return r;
}

void vpush(void)
{
    if (vstack_ptr >= vstack + VSTACK_SIZE)
        error("memory full");
    *vstack_ptr++ = vt;
    *vstack_ptr++ = vc;
    /* cannot let cpu flags if other instruction are generated */
    if ((vt & VT_VALMASK) == VT_CMP)
        gvp(vstack_ptr - 2);
}

void vpop(int *ft, int *fc)
{
    *fc = *--vstack_ptr;
    *ft = *--vstack_ptr;
}

/* generate a value in a register from vt and vc */
int gv(void)
{
    int r;
    vpush();
    r = gvp(vstack_ptr - 2);
    vpop(&vt, &vc);
    return r;
}

/* handle constant optimizations and various machine independant opt */
void gen_opc(op)
{
    int fr, ft, fc, r, c1, c2, n;

    vpop(&ft, &fc);
    vpop(&vt, &vc);
    c1 = (vt & (VT_VALMASK | VT_LVAL)) == VT_CONST;
    c2 = (ft & (VT_VALMASK | VT_LVAL)) == VT_CONST;
    if (c1 && c2) {
        switch(op) {
        case '+': vc += fc; break;
        case '-': vc -= fc; break;
        case '&': vc &= fc; break;
        case '^': vc ^= fc; break;
        case '|': vc |= fc; break;
        case '*': vc *= fc; break;
        case TOK_PDIV:
        case '/': vc /= fc; break; /* XXX: zero case ? */
        case '%': vc %= fc; break; /* XXX: zero case ? */
        case TOK_UDIV: vc = (unsigned)vc / fc; break; /* XXX: zero case ? */
        case TOK_UMOD: vc = (unsigned)vc % fc; break; /* XXX: zero case ? */
        case TOK_SHL: vc <<= fc; break;
        case TOK_SHR: vc = (unsigned)vc >> fc; break;
        case TOK_SAR: vc >>= fc; break;
            /* tests */
        case TOK_ULT: vc = (unsigned)vc < (unsigned)fc; break;
        case TOK_UGE: vc = (unsigned)vc >= (unsigned)fc; break;
        case TOK_EQ: vc = vc == fc; break;
        case TOK_NE: vc = vc != fc; break;
        case TOK_ULE: vc = (unsigned)vc <= (unsigned)fc; break;
        case TOK_UGT: vc = (unsigned)vc > (unsigned)fc; break;
        case TOK_LT: vc = vc < fc; break;
        case TOK_GE: vc = vc >= fc; break;
        case TOK_LE: vc = vc <= fc; break;
        case TOK_GT: vc = vc > fc; break;
            /* logical */
        case TOK_LAND: vc = vc && fc; break;
        case TOK_LOR: vc = vc || fc; break;
        default:
            goto general_case;
        }
    } else {
        /* if commutative ops, put c2 as constant */
        if (c1 && (op == '+' || op == '&' || op == '^' || 
                   op == '|' || op == '*')) {
            swap(&vt, &ft);
            swap(&vc, &fc);
            swap(&c1, &c2);
        }
        if (c2 && (((op == '*' || op == '/' || op == TOK_UDIV || 
                     op == TOK_PDIV) && 
                    fc == 1) ||
                   ((op == '+' || op == '-' || op == '|' || op == '^' || 
                     op == TOK_SHL || op == TOK_SHR || op == TOK_SAR) && 
                    fc == 0) ||
                   (op == '&' && 
                    fc == -1))) {
        } else if (c2 && (op == '*' || op == TOK_PDIV || op == TOK_UDIV)) {
            /* try to use shifts instead of muls or divs */
            if (fc > 0 && (fc & (fc - 1)) == 0) {
                n = -1;
                while (fc) {
                    fc >>= 1;
                    n++;
                }
                fc = n;
                if (op == '*')
                    op = TOK_SHL;
                else if (op == TOK_PDIV)
                    op = TOK_SAR;
                else
                    op = TOK_SHR;
            }
            goto general_case;
        } else {
        general_case:
            vpush();
            vt = ft;
            vc = fc;
            vpush();
            r = gvp(vstack_ptr - 4);
            fr = gvp(vstack_ptr - 2);
            vpop(&ft, &fc);
            vpop(&vt, &vc);
            /* call low level op generator */
            gen_op1(op, r, fr);
        }
    }
}

int pointed_size(int t)
{
    return type_size(pointed_type(t), &t);
}

/* generic gen_op: handles types problems */
void gen_op(int op)
{
    int u, t1, t2;

    vpush();
    t1 = vstack_ptr[-4];
    t2 = vstack_ptr[-2];
    if (op == '+' | op == '-') {
        if ((t1 & VT_PTR) && (t2 & VT_PTR)) {
            if (op != '-')
                error("invalid type");
            /* XXX: check that types are compatible */
            u = pointed_size(t1);
            gen_opc(op);
            vpush();
            vstack_ptr[-2] &= ~VT_TYPE; /* set to integer */
            vset(VT_CONST, u);
            gen_op(TOK_PDIV);
        } else if ((t1 | t2) & VT_PTR) {
            if (t2 & VT_PTR) {
                swap(vstack_ptr - 4, vstack_ptr - 2);
                swap(vstack_ptr - 3, vstack_ptr - 1);
                swap(&t1, &t2);
            }
            /* stack-4 contains pointer, stack-2 value to add */
            vset(VT_CONST, pointed_size(vstack_ptr[-4]));
            gen_op('*');
            vpush();
            gen_opc(op);
            /* put again type if gen_opc() swaped operands */
            vt = (vt & VT_TYPEN) | (t1 & VT_TYPE);
        } else {
            gen_opc(op);
        }
    } else {
        /* XXX: test types and compute returned value */
        if ((t1 | t2) & (VT_UNSIGNED | VT_PTR)) {
            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;
        }
        gen_opc(op);
    }
}

/* cast (vt, vc) to 't' type */
void gen_cast(int t)
{
    int r, bits;
    r = vt & VT_VALMASK;
    if (!(t & VT_LVAL)) {
        /* if not lvalue, then we convert now */
        if ((t & VT_TYPE & ~VT_UNSIGNED) == VT_BYTE)
            bits = 8;
        else if ((t & VT_TYPE & ~VT_UNSIGNED) == VT_SHORT)
            bits = 16;
        else
            goto the_end;
        vpush();
        if (t & VT_UNSIGNED) {
            vset(VT_CONST, (1 << bits) - 1);
            gen_op('&');
        } else {
            bits = 32 - bits;
            vset(VT_CONST, bits);
            gen_op(TOK_SHL);
            vpush();
            vset(VT_CONST, bits);
            gen_op(TOK_SAR);
        }
    }
 the_end:
    vt = (vt & VT_TYPEN) | t;
}

/* return type size. Put alignment at 'a' */
int type_size(int t, int *a)
{
    Sym *s;

    /* int, enum or pointer */
    if (t & VT_STRUCT) {
        /* struct/union */
        s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT) | SYM_STRUCT);
        *a = 4; /* XXX: cannot store it yet. Doing that is safe */
        return s->c;
    } else if (t & VT_ARRAY) {
        s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT));
        return type_size(s->t, a) * s->c;
    } else if ((t & VT_PTR) | 
               (t & VT_TYPE) == 0 |
               (t & VT_ENUM)) {
        *a = 4;
        return 4;
    } else if (t & VT_SHORT) {
        *a = 2;
        return 2;
    } else {
        *a = 1;
        return 1;
    }
}

/* return the pointed type of t */
int pointed_type(int t)
{
    Sym *s;
    s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT));
    return s->t | (t & VT_TYPEN);
}

int mk_pointer(int t)
{
    int p;
    p = anon_sym++;
    sym_push(p, t, -1);
    return VT_PTR | (p << VT_STRUCT_SHIFT) | (t & VT_TYPEN);
}

/* store value in lvalue pushed on stack */
void vstore(void)
{
    int ft, fc, r, t, size, align;
    GFuncContext gf;

    if (vt & VT_STRUCT) {
        /* if structure, only generate pointer */
        /* structure assignment : generate memcpy */
        /* XXX: optimize if small size */

        gfunc_start(&gf);
        /* type size */
        ft = vt;
        fc = vc;
        size = type_size(vt, &align);
        vset(VT_CONST, size);
        gfunc_param(&gf);
        /* source */
        vt = ft & ~VT_LVAL;
        vc = fc;
        gfunc_param(&gf);
        /* destination */
        vpop(&vt, &vc);
        vt &= ~VT_LVAL;
        gfunc_param(&gf);

        save_regs();
        gfunc_call(&gf, VT_CONST, (int)&memcpy);

        /* generate again current type */
        vt = ft;
        vc = fc;
    } else {
        r = gv();  /* generate value */
        vpush();
        ft = vstack_ptr[-4];
        fc = vstack_ptr[-3];
        /* if lvalue was saved on stack, must read it */
        if ((ft & VT_VALMASK) == VT_LLOCAL) {
            t = get_reg();
            load(t, VT_LOCAL | VT_LVAL, fc);
            ft = (ft & ~VT_VALMASK) | t;
        }
        store(r, ft, fc);
        vstack_ptr -= 4;
    }
}

/* post defines POST/PRE add. c is the token ++ or -- */
void inc(post, c)
{
    int r, r1;
    test_lvalue();
    if (post)
        vpush(); /* room for returned value */
    vpush(); /* save lvalue */
    r = gv();
    vpush(); /* save value */
    if (post) {
        /* duplicate value */
        r1 = get_reg();
        load(r1, r, 0); /* move r to r1 */
        vstack_ptr[-6] = (vt & VT_TYPE) | r1;
        vstack_ptr[-5] = 0;
    }
    /* add constant */
    vset(VT_CONST, c - TOK_MID); 
    gen_op('+');
    vstore(); /* store value */
    if (post)
        vpop(&vt, &vc);
}

/* enum/struct/union declaration */
int struct_decl(int u)
{
    int a, t, b, v, size, align, maxalign, c;
    Sym *s, *ss, **ps;

    a = tok; /* save decl type */
    next();
    if (tok != '{') {
        v = tok;
        next();
        /* struct already defined ? return it */
        /* XXX: check consistency */
        if (s = sym_find(v | SYM_STRUCT)) {
            if (s->t != a)
                error("invalid type");
            goto do_decl;
        }
    } else {
        v = anon_sym++;
    }
    s = sym_push(v | SYM_STRUCT, a, 0);
    /* put struct/union/enum name in type */
 do_decl:
    u = u | (v << VT_STRUCT_SHIFT);
    
    if (tok == '{') {
        next();
        if (s->c)
            error("struct/union/enum already defined");
        /* cannot be empty */
        c = 0;
        maxalign = 0;
        ps = &s->next;
        while (1) {
            if (a == TOK_ENUM) {
                v = tok;
                next();
                if (tok == '=') {
                    next();
                    c = expr_const();
                }
                sym_push(v, VT_CONST, c);
                if (tok == ',')
                    next();
                c++;
            } else {
                b = ist();
                while (1) {
                    t = type_decl(&v, b, TYPE_DIRECT);
                    if (t & (VT_FUNC | VT_TYPEDEF))
                        error("invalid type");
                    /* XXX: align & correct type size */
                    v |= SYM_FIELD;
                    size = type_size(t, &align);
                    if (a == TOK_STRUCT) {
                        c = (c + align - 1) & -align;
                        ss = sym_push(v, t, c);
                        c += size;
                    } else {
                        ss = sym_push(v, t, 0);
                        if (size > c)
                            c = size;
                    }
                    if (align > maxalign)
                        maxalign = align;
                    *ps = ss;
                    ps = &ss->next;
                    if (tok == ';' || tok == -1)
                        break;
                    skip(',');
                }
                skip(';');
            }
            if (tok == '}')
                break;
        }
        skip('}');
        /* size for struct/union, dummy for enum */
        s->c = (c + maxalign - 1) & -maxalign; 
    }
    return u;
}

/* return 0 if no type declaration. otherwise, return the basic type
   and skip it. 
   XXX: A '2' is ored to ensure non zero return if int type.
 */
int ist(void)
{
    int t;
    Sym *s;

    t = 0;
    while(1) {
        if (tok == TOK_ENUM) {
            t |= struct_decl(VT_ENUM);
        } else if (tok == TOK_STRUCT || tok == TOK_UNION) {
            t |= struct_decl(VT_STRUCT);
        } else {
            if (tok == TOK_CHAR) {
                t |= VT_BYTE;
            } else if (tok == TOK_VOID) {
                t |= VT_VOID;
            } else if (tok == TOK_SHORT) {
                t |= VT_SHORT;
            } else if (tok == TOK_INT |
                       (tok >= TOK_CONST & tok <= TOK_INLINE)) {
                /* ignored types */
            } else if (tok == TOK_FLOAT || tok == TOK_DOUBLE) {
                /* We allow that to compile standard headers */
                //                warning("floats not supported");
            } else if (tok == TOK_EXTERN) {
                t |= VT_EXTERN;
            } else if (tok == TOK_STATIC) {
                t |= VT_STATIC;
            } else if (tok == TOK_UNSIGNED) {
                t |= VT_UNSIGNED;
            } else if (tok == TOK_TYPEDEF) {
                t |= VT_TYPEDEF;
            } else {
                s = sym_find(tok);
                if (!s || !(s->t & VT_TYPEDEF))
                    break;
                t |= (s->t & ~VT_TYPEDEF);
            }
            next();
        }
        t |= 2;
    }
    return t;
}

int post_type(t)
{
    int p, n, pt, l;
    Sym **plast, *s, *first;

    if (tok == '(') {
        /* function declaration */
        next();
        l = 0;
        first = NULL;
        plast = &first;
        while (tok != ')') {
            /* read param name and compute offset */
            if (l != FUNC_OLD) {
                if (!(pt = ist())) {
                    if (l) {
                        error("invalid type");
                    } else {
                        l = FUNC_OLD;
                        goto old_proto;
                    }
                }
                if (pt & VT_VOID && tok == ')')
                    break;
                l = FUNC_NEW;
                pt = type_decl(&n, pt, TYPE_DIRECT | TYPE_ABSTRACT);
            } else {
            old_proto:
                n = tok;
                pt = VT_INT;
                next();
            }
            /* array must be transformed to pointer according to ANSI C */
            pt &= ~VT_ARRAY;
            s = sym_push(n | SYM_FIELD, pt, 0);
            *plast = s;
            plast = &s->next;
            if (tok == ',') {
                next();
                if (l == FUNC_NEW && tok == TOK_DOTS) {
                    l = FUNC_ELLIPSIS;
                    next();
                    break;
                }
            }
        }
        skip(')');
        t = post_type(t);
        /* we push a anonymous symbol which will contain the function prototype */
        p = anon_sym++;
        s = sym_push(p, t, l);
        s->next = first;
        t = VT_FUNC | (p << VT_STRUCT_SHIFT);
    } else if (tok == '[') {
        /* array definition */
        next();
        n = -1;
        if (tok != ']') {
            n = expr_const();
            if (n < 0)
                error("invalid array size");    
        }
        skip(']');
        /* parse next post type */
        t = post_type(t);
        
        /* we push a anonymous symbol which will contain the array
           element type */
        p = anon_sym++;
        sym_push(p, t, n);
        t = VT_ARRAY | VT_PTR | (p << VT_STRUCT_SHIFT);
    }
    return t;
}

/* Read a type declaration (except basic type), and return the
   type. If v is true, then also put variable name in 'vc' */
int type_decl(int *v, int t, int td)
{
    int u, p;
    Sym *s;

    t = t & -3; /* suppress the ored '2' */
    while (tok == '*') {
        next();
        while (tok == TOK_CONST || tok == TOK_VOLATILE || tok == TOK_RESTRICT)
            next();
        t = mk_pointer(t);
    }
    
    /* recursive type */
    /* XXX: incorrect if abstract type for functions (e.g. 'int ()') */
    if (tok == '(') {
        next();
        u = type_decl(v, 0, td);
        skip(')');
    } else {
        u = 0;
        /* type identifier */
        if (tok >= TOK_IDENT && (td & TYPE_DIRECT)) {
            *v = tok;
            next();
        } else {
            if (!(td & TYPE_ABSTRACT))
                expect("identifier");
            *v = 0;
        }
    }
    /* append t at the end of u */
    t = post_type(t);
    if (!u) 
        return t;
    p = u;
    while(1) {
        s = sym_find((unsigned)p >> VT_STRUCT_SHIFT);
        p = s->t;
        if (!p) {
            s->t = t;
            break;
        }
    }
    return u;
}

/* define a new external reference to a function 'v' of type 'u' */
Sym *external_sym(int v, int u)
{
    Sym *s;
    s = sym_find(v);
    if (!s) {
        /* push forward reference */
        s = sym_push1(&global_stack, 
                      v, u | VT_CONST | VT_FORWARD, 0);
    }
    return s;
}

void indir(void)
{
    if (vt & VT_LVAL)
        gv();
    if (!(vt & VT_PTR))
        expect("pointer");
    vt = pointed_type(vt);
    if (!(vt & VT_ARRAY)) /* an array is never an lvalue */
        vt |= VT_LVAL;
}

void unary(void)
{
    int n, t, ft, fc, p, align, size;
    Sym *s;
    GFuncContext gf;

    if (tok == TOK_NUM || tok == TOK_CCHAR || tok == TOK_LCHAR) {
        vset(VT_CONST, tokc);
        next();
    } else if (tok == TOK___FUNC__) {
        /* special function name identifier */
        /* generate (char *) type */
        vset(VT_CONST | mk_pointer(VT_BYTE), glo);
        strcpy((void *)glo, funcname);
        glo += strlen(funcname) + 1;
    } else if (tok == TOK_LSTR) {
        t = VT_INT;
        goto str_init;
    } else if (tok == TOK_STR) {
        /* string parsing */
        t = VT_BYTE;
    str_init:
        type_size(t, &align);
        glo = (glo + align - 1) & -align;
        fc = glo;
        /* we must declare it as an array first to use initializer parser */
        t = VT_CONST | VT_ARRAY | mk_pointer(t);
        decl_initializer(t, glo, 1, 0);
        glo += type_size(t, &align);
        /* put it as pointer */
        vset(t & ~VT_ARRAY, fc);
    } else {
        t = tok;
        next();
        if (t == '(') {
            /* cast ? */
            if (t = ist()) {
                ft = type_decl(&n, t, TYPE_ABSTRACT);
                skip(')');
                /* check ISOC99 compound literal */
                if (tok == '{') {
                    /* data is allocated locally by default */
                    if (global_expr)
                        ft |= VT_CONST;
                    else
                        ft |= VT_LOCAL;
                    /* all except arrays are lvalues */
                    if (!(ft & VT_ARRAY))
                        ft |= VT_LVAL;
                    fc = decl_initializer_alloc(ft, 1);
                    vset(ft, fc);
                } else {
                    unary();
                    gen_cast(ft);
                }
            } else {
                expr();
                skip(')');
            }
        } else if (t == '*') {
            unary();
            indir();
        } else if (t == '&') {
            unary();
            /* functions names must be treated as function pointers,
               except for unary '&' and sizeof. Since we consider that
               functions are not lvalues, we only have to handle it
               there and in function calls. */
            if (!(vt & VT_FUNC))
                test_lvalue();
            vt = mk_pointer(vt & VT_LVALN);
        } else
        if (t == '!') {
            unary();
            if ((vt & (VT_CONST | VT_LVAL)) == VT_CONST) 
                vc = !vc;
            else if ((vt & VT_VALMASK) == VT_CMP)
                vc = vc ^ 1;
            else
                vset(VT_JMP, gtst(1, 0));
        } else
        if (t == '~') {
            unary();
            vpush();
            vset(VT_CONST, -1);
            gen_op('^');
        } else 
        if (t == '+') {
            unary();
        } else 
        if (t == TOK_SIZEOF) {
            /* XXX: some code can be generated */
            if (tok == '(') {
                next();
                if (t = ist())
                    vt = type_decl(&n, t, TYPE_ABSTRACT);
                else
                    expr();
                skip(')');
            } else {
                unary();
            }
            vset(VT_CONST, type_size(vt, &t));
        } else
        if (t == TOK_INC | t == TOK_DEC) {
            unary();
            inc(0, t);
        } else if (t == '-') {
            vset(VT_CONST, 0);
            vpush();
            unary();
            gen_op('-');
        } else 
        {
            s = sym_find(t);
            if (!s) {
                if (tok != '(')
                    error("'%s' undeclared", get_tok_str(t, 0));
                /* for simple function calls, we tolerate undeclared
                   external reference */
                p = anon_sym++;        
                sym_push1(&global_stack, p, 0, FUNC_OLD);
                /* int() function */
                s = external_sym(t, VT_FUNC | (p << VT_STRUCT_SHIFT)); 
            }
            vset(s->t, s->c);
            /* if forward reference, we must point to s */
            if (vt & VT_FORWARD)
                vc = (int)s;
        }
    }
    
    /* post operations */
    while (1) {
        if (tok == TOK_INC | tok == TOK_DEC) {
            inc(1, tok);
            next();
        } else if (tok == '.' | tok == TOK_ARROW) {
            /* field */ 
            if (tok == TOK_ARROW) 
                indir();
            test_lvalue();
            vt &= VT_LVALN;
            next();
            /* expect pointer on structure */
            if (!(vt & VT_STRUCT))
                expect("struct or union");
            s = sym_find(((unsigned)vt >> VT_STRUCT_SHIFT) | SYM_STRUCT);
            /* find field */
            tok |= SYM_FIELD;
            while (s = s->next) {
                if (s->v == tok)
                    break;
            }
            if (!s)
                error("field not found");
            /* add field offset to pointer */
            vt = vt & VT_TYPEN; /* change type to int */
            vpush();
            vset(VT_CONST, s->c);
            gen_op('+');
            /* change type to field type, and set to lvalue */
            vt = (vt & VT_TYPEN) | s->t;
            /* an array is never an lvalue */
            if (!(vt & VT_ARRAY))
                vt |= VT_LVAL;
            next();
        } else if (tok == '[') {
            next();
            vpush();
            expr();
            gen_op('+');
            indir();
            skip(']');
        } else if (tok == '(') {
            int rett, retc;

            /* function call  */
            if (!(vt & VT_FUNC)) {
                if ((vt & (VT_PTR | VT_ARRAY)) == VT_PTR) {
                    vt = pointed_type(vt);
                    if (!(vt & VT_FUNC))
                        goto error_func;
                } else {
                error_func:
                    expect("function type");
                }
            }
            /* get return type */
            s = sym_find((unsigned)vt >> VT_STRUCT_SHIFT);

            vt &= ~VT_LVAL; /* no lvalue */
            vpush(); /* push function address */
            save_regs(); /* save used temporary registers */
            gfunc_start(&gf);
            next();
#ifdef INVERT_FUNC_PARAMS
            {
                int *str, len, parlevel, *saved_macro_ptr;
                Sym *args, *s1;

                /* read each argument and store it on a stack */
                /* XXX: merge it with macro args ? */
                args = NULL;
                while (tok != ')') {
                    len = 0;
                    str = NULL;
                    parlevel = 0;
                    while ((parlevel > 0 || (tok != ')' && tok != ',')) && 
                           tok != -1) {
                        if (tok == '(')
                            parlevel++;
                        else if (tok == ')')
                            parlevel--;
                        tok_add2(&str, &len, tok, tokc);
                        next();
                    }
                    tok_add(&str, &len, -1); /* end of file added */
                    tok_add(&str, &len, 0);
                    sym_push2(&args, 0, 0, (int)str);
                    if (tok != ',')
                        break;
                    next();
                }
                if (tok != ')')
                    expect(")");
                
                /* now generate code in reverse order by reading the stack */
                saved_macro_ptr = macro_ptr;
                while (args) {
                    macro_ptr = (int *)args->c;
                    next();
                    expr_eq();
                    gfunc_param(&gf);
                    s1 = args->prev;
                    free((int *)args->c);
                    free(args);
                    args = s1;
                }
                macro_ptr = saved_macro_ptr;
                /* restore token */
                tok = ')';
            }
#endif
            /* compute first implicit argument if a structure is returned */
            if (s->t & VT_STRUCT) {
                /* get some space for the returned structure */
                size = type_size(s->t, &align);
                loc = (loc - size) & -align;
                rett = s->t | VT_LOCAL | VT_LVAL;
                /* pass it as 'int' to avoid structure arg passing
                   problems */
                vset(VT_INT | VT_LOCAL, loc);
                retc = vc;
                gfunc_param(&gf);
            } else {
                rett = s->t | FUNC_RET_REG; /* return in register */
                retc = 0;
            }
#ifndef INVERT_FUNC_PARAMS
            while (tok != ')') {
                expr_eq();
                gfunc_param(&gf);
                if (tok == ',')
                    next();
            }
#endif
            skip(')');
            vpop(&ft, &fc);
            gfunc_call(&gf, ft, fc);
            /* return value */
            vt = rett;
            vc = retc;
        } else {
            break;
        }
    }
}

int is_compatible_types(int t1, int t2)
{
    Sym *s1, *s2;

    t1 &= VT_TYPE;
    t2 &= VT_TYPE;
    if (t1 & VT_PTR) {
        t1 = pointed_type(t1);
        /* if function, then convert implictely to function pointer */
        if (!(t2 & VT_FUNC)) {
            if (!(t2 & VT_PTR))
                return 0;
            t2 = pointed_type(t2);
        }
        /* void matches everything */
        t1 &= VT_TYPE;
        t2 &= VT_TYPE;
        if (t1 == VT_VOID || t2 == VT_VOID)
            return 1;
        return is_compatible_types(t1, t2);
    } else if (t1 & VT_STRUCT) {
        return (t2 == t1);
    } else if (t1 & VT_FUNC) {
        if (!(t2 & VT_FUNC))
            return 0;
        s1 = sym_find(((unsigned)t1 >> VT_STRUCT_SHIFT));
        s2 = sym_find(((unsigned)t2 >> VT_STRUCT_SHIFT));
        if (!is_compatible_types(s1->t, s2->t))
            return 0;
        /* XXX: not complete */
        if (s1->c == FUNC_OLD || s2->c == FUNC_OLD)
            return 1;
        if (s1->c != s2->c)
            return 0;
        while (s1 != NULL) {
            if (s2 == NULL)
                return 0;
            if (!is_compatible_types(s1->t, s2->t))
                return 0;
            s1 = s1->next;
            s2 = s2->next;
        }
        if (s2)
            return 0;
        return 1;
    } else {
        /* XXX: not complete */
        return 1;
    }
}

int check_assign_types(int t1, int t2)
{
    t1 &= VT_TYPE;
    t2 &= VT_TYPE;
    if ((t1 & VT_PTR) && (t2 & VT_FUNC)) {
        return is_compatible_types(pointed_type(t1), t2);
    } else {
        return is_compatible_types(t1, t2);
    }
}


void uneq()
{
    int t;
    
    unary();
    if (tok == '=' | 
        (tok >= TOK_A_MOD & tok <= TOK_A_DIV) |
        tok == TOK_A_XOR | tok == TOK_A_OR | 
        tok == TOK_A_SHL | tok == TOK_A_SAR) {
        test_lvalue();
        vpush();
        t = tok;
        next();
        if (t == '=') {
            expr_eq();
            if (!check_assign_types(vstack_ptr[-2], vt))
                warning("incompatible types");
        } else {
            vpush();
            expr_eq();
            gen_op(t & 0x7f);
        }
        vstore();
    }
}

void sum(l)
{
    int t;

    if (l == 0)
        uneq();
    else {
        sum(--l);
        while ((l == 0 & (tok == '*' | tok == '/' | tok == '%')) |
               (l == 1 & (tok == '+' | tok == '-')) |
               (l == 2 & (tok == TOK_SHL | tok == TOK_SAR)) |
               (l == 3 & ((tok >= TOK_ULE & tok <= TOK_GT) |
                          tok == TOK_ULT | tok == TOK_UGE)) |
               (l == 4 & (tok == TOK_EQ | tok == TOK_NE)) |
               (l == 5 & tok == '&') |
               (l == 6 & tok == '^') |
               (l == 7 & tok == '|') |
               (l == 8 & tok == TOK_LAND) |
               (l == 9 & tok == TOK_LOR)) {
            vpush();
            t = tok;
            next();
            sum(l);
            gen_op(t);
       }
    }
}

/* only used if non constant */
void eand()
{
    int t;

    sum(8);
    t = 0;
    while (1) {
        if (tok != TOK_LAND) {
            if (t) {
                t = gtst(1, t);
                vset(VT_JMPI, t);
            }
            break;
        }
        t = gtst(1, t);
        next();
        sum(8);
    }
}

void eor()
{
    int t;

    eand();
    t = 0;
    while (1) {
        if (tok != TOK_LOR) {
            if (t) {
                t = gtst(0, t);
                vset(VT_JMP, t);
            }
            break;
        }
        t = gtst(0, t);
        next();
        eand();
    }
}

/* XXX: better constant handling */
void expr_eq()
{
    int t, u, c, r1, r2;

    if (const_wanted) {
        sum(10);
        if (tok == '?') {
            c = vc;
            next();
            expr();
            t = vc;
            skip(':');
            expr_eq();
            if (c)
                vc = t;
        }
    } else {
        eor();
        if (tok == '?') {
            next();
            t = gtst(1, 0);
            expr();
            r1 = gv();
            skip(':');
            u = gjmp(0);
            gsym(t);
            expr_eq();
            r2 = gv();
            move_reg(r1, r2);
            vt = (vt & VT_TYPE) | r1;
            gsym(u);
        }
    }
}

void expr()
{
    while (1) {
        expr_eq();
        if (tok != ',')
            break;
        next();
    }
}

int expr_const()
{
    int a;
    a = const_wanted;
    const_wanted = 1;
    expr_eq();
    if ((vt & (VT_CONST | VT_LVAL)) != VT_CONST)
        expect("constant");
    const_wanted = a;
    return vc;
}

/* return the label token if current token is a label, otherwise
   return zero */
int is_label(void)
{
    int t, c;

    /* fast test first */
    if (tok < TOK_UIDENT)
        return 0;
    t = tok;
    c = tokc;
    next();
    if (tok == ':') {
        next();
        return t;
    } else {
        /* XXX: may not work in all cases (macros ?) */
        tok1 = tok;
        tok1c = tokc;
        tok = t;
        tokc = c;
        return 0;
    }
}

void block(int *bsym, int *csym, int *case_sym, int *def_sym, int case_reg)
{
    int a, b, c, d;
    Sym *s;

    if (tok == TOK_IF) {
        /* if test */
        next();
        skip('(');
        expr();
        skip(')');
        a = gtst(1, 0);
        block(bsym, csym, case_sym, def_sym, case_reg);
        c = tok;
        if (c == TOK_ELSE) {
            next();
            d = gjmp(0);
            gsym(a);
            block(bsym, csym, case_sym, def_sym, case_reg);
            gsym(d); /* patch else jmp */
        } else
            gsym(a);
    } else if (tok == TOK_WHILE) {
        next();
        d = ind;
        skip('(');
        expr();
        skip(')');
        a = gtst(1, 0);
        b = 0;
        block(&a, &b, case_sym, def_sym, case_reg);
        oad(0xe9, d - ind - 5); /* jmp */
        gsym(a);
        gsym_addr(b, d);
    } else if (tok == '{') {
        next();
        /* declarations */
        s = local_stack.top;
        while (tok != '}') {
            decl(VT_LOCAL);
            if (tok != '}')
                block(bsym, csym, case_sym, def_sym, case_reg);
        }
        /* pop locally defined symbols */
        sym_pop(&local_stack, s);
        next();
    } else if (tok == TOK_RETURN) {
        next();
        if (tok != ';') {
            if (func_vt & VT_STRUCT) {
                /* if returning structure, must copy it to implicit
                   first pointer arg location */
                vset(mk_pointer(func_vt) | VT_LOCAL | VT_LVAL, func_vc);
                indir();
                vpush();
            }
            expr();
            if (func_vt & VT_STRUCT) {
                /* copy structure value to pointer */
                vstore();
            } else {
                /* move return value to standard return register */
                move_reg(FUNC_RET_REG, gv());
            }
        }
        skip(';');
        rsym = gjmp(rsym); /* jmp */
    } else if (tok == TOK_BREAK) {
        /* compute jump */
        if (!bsym)
            error("cannot break");
        *bsym = gjmp(*bsym);
        next();
        skip(';');
    } else if (tok == TOK_CONTINUE) {
        /* compute jump */
        if (!csym)
            error("cannot continue");
        *csym = gjmp(*csym);
        next();
        skip(';');
    } else if (tok == TOK_FOR) {
        int e;
        next();
        skip('(');
        if (tok != ';')
            expr();
        skip(';');
        d = ind;
        c = ind;
        a = 0;
        b = 0;
        if (tok != ';') {
            expr();
            a = gtst(1, 0);
        }
        skip(';');
        if (tok != ')') {
            e = gjmp(0);
            c = ind;
            expr();
            oad(0xe9, d - ind - 5); /* jmp */
            gsym(e);
        }
        skip(')');
        block(&a, &b, case_sym, def_sym, case_reg);
        oad(0xe9, c - ind - 5); /* jmp */
        gsym(a);
        gsym_addr(b, c);
    } else 
    if (tok == TOK_DO) {
        next();
        a = 0;
        b = 0;
        d = ind;
        block(&a, &b, case_sym, def_sym, case_reg);
        skip(TOK_WHILE);
        skip('(');
        gsym(b);
        expr();
        c = gtst(0, 0);
        gsym_addr(c, d);
        skip(')');
        gsym(a);
        skip(';');
    } else
    if (tok == TOK_SWITCH) {
        next();
        skip('(');
        expr();
        case_reg = gv();
        skip(')');
        a = 0;
        b = 0;
        c = 0;
        block(&a, csym, &b, &c, case_reg);
        /* if no default, jmp after switch */
        if (c == 0)
            c = ind;
        /* default label */
        gsym_addr(b, c);
        /* break label */
        gsym(a);
    } else
    if (tok == TOK_CASE) {
        next();
        a = expr_const();
        if (!case_sym)
            expect("switch");
        gsym(*case_sym);
        vset(case_reg, 0);
        vpush();
        vset(VT_CONST, a);
        gen_op(TOK_EQ);
        *case_sym = gtst(1, 0);
        skip(':');
        block(bsym, csym, case_sym, def_sym, case_reg);
    } else 
    if (tok == TOK_DEFAULT) {
        next();
        skip(':');
        if (!def_sym)
            expect("switch");
        if (*def_sym)
            error("too many 'default'");
        *def_sym = ind;
        block(bsym, csym, case_sym, def_sym, case_reg);
    } else
    if (tok == TOK_GOTO) {
        next();
        s = sym_find1(&label_stack, tok);
        /* put forward definition if needed */
        if (!s)
            s = sym_push1(&label_stack, tok, VT_FORWARD, 0);
        /* label already defined */
        if (s->t & VT_FORWARD) 
            s->c = gjmp(s->c); /* jmp xxx */
        else
            oad(0xe9, s->c - ind - 5); /* jmp xxx */
        next();
        skip(';');
    } else {
        b = is_label();
        if (b) {
            /* label case */
            s = sym_find1(&label_stack, b);
            if (s) {
                if (!(s->t & VT_FORWARD))
                    error("multiple defined label");
                gsym(s->c);
                s->c = ind;
                s->t = 0;
            } else {
                sym_push1(&label_stack, b, 0, ind);
            }
            /* we accept this, but it is a mistake */
            if (tok == '}') 
                warning("deprecated use of label at end of compound statement");
            else
                block(bsym, csym, case_sym, def_sym, case_reg);
        } else {
            /* expression case */
            if (tok != ';') {
                expr();
            }
            skip(';');
        }
    }
}

/* t is the array or struct type. c is the array or struct
   address. cur_index/cur_field is the pointer to the current
   value. 'size_only' is true if only size info is needed (only used
   in arrays) */
void decl_designator(int t, int c, 
                     int *cur_index, Sym **cur_field, 
                     int size_only)
{
    Sym *s, *f;
    int notfirst, index, align, l;

    notfirst = 0;
    if (gnu_ext && (l = is_label()) != 0)
        goto struct_field;

    while (tok == '[' || tok == '.') {
        if (tok == '[') {
            if (!(t & VT_ARRAY))
                expect("array type");
            s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT));
            next();
            index = expr_const();
            if (index < 0 || (s->c >= 0 && index >= s->c))
                expect("invalid index");
            skip(']');
            if (!notfirst)
                *cur_index = index;
            t = pointed_type(t);
            c += index * type_size(t, &align);
        } else {
            next();
            l = tok;
            next();
        struct_field:
            if (!(t & VT_STRUCT))
                expect("struct/union type");
            s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT) | SYM_STRUCT);
            l |= SYM_FIELD;
            f = s->next;
            while (f) {
                if (f->v == l)
                    break;
                f = f->next;
            }
            if (!f)
                expect("field");
            if (!notfirst)
                *cur_field = f;
            t = f->t | (t & VT_TYPEN);
            c += f->c;
        }
        notfirst = 1;
    }
    if (notfirst) {
        if (tok == '=') {
            next();
        } else {
            if (!gnu_ext)
                expect("=");
        }
    } else {
        if (t & VT_ARRAY) {
            index = *cur_index;
            t = pointed_type(t);
            c += index * type_size(t, &align);
        } else {
            f = *cur_field;
            if (!f)
                error("too many field init");
            t = f->t | (t & VT_TYPEN);
            c += f->c;
        }
    }
    decl_initializer(t, c, 0, size_only);
}

/* store a value or an expression directly in global data or in local array */

void init_putv(int t, int c, int v, int is_expr)
{
    int saved_global_expr;

    if ((t & VT_VALMASK) == VT_CONST) {
        if (is_expr) {
            /* compound literals must be allocated globally in this case */
            saved_global_expr = global_expr;
            global_expr = 1;
            v = expr_const();
            global_expr = saved_global_expr;
        }
        if (t & VT_BYTE)
            *(char *)c = v;
        else if (t & VT_SHORT)
            *(short *)c = v;
        else
            *(int *)c = v;
    } else {
        vt = t;
        vc = c;
        vpush();
        if (is_expr)
            expr_eq();
        else
            vset(VT_CONST, v);
        vstore();
    }
}

/* put zeros for variable based init */
void init_putz(int t, int c, int size)
{
    GFuncContext gf;

    if ((t & VT_VALMASK) == VT_CONST) {
        /* nothing to do because global are already set to zero */
    } else {
        gfunc_start(&gf);
        vset(VT_CONST, size);
        gfunc_param(&gf);
        vset(VT_CONST, 0);
        gfunc_param(&gf);
        vset(VT_LOCAL, c);
        gfunc_param(&gf);
        gfunc_call(&gf, VT_CONST, (int)&memset);
    }
}

/* 't' contains the type and storage info. c is the address of the
   object. 'first' is true if array '{' must be read (multi dimension
   implicit array init handling). 'size_only' is true if size only
   evaluation is wanted (only for arrays). */
void decl_initializer(int t, int c, int first, int size_only)
{
    int index, array_length, n, no_oblock, nb, parlevel, i;
    int t1, size1, align1;
    Sym *s, *f;
    TokenSym *ts;

    if (t & VT_ARRAY) {
        s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT));
        n = s->c;
        array_length = 0;
        t1 = pointed_type(t);
        size1 = type_size(t1, &align1);

        no_oblock = 1;
        if ((first && tok != TOK_LSTR && tok != TOK_STR) || 
            tok == '{') {
            skip('{');
            no_oblock = 0;
        }

        /* only parse strings here if correct type (otherwise: handle
           them as ((w)char *) expressions */
        if ((tok == TOK_LSTR && 
             (t1 & VT_TYPE & ~VT_UNSIGNED) == VT_INT) ||
            (tok == TOK_STR &&
             (t1 & VT_TYPE & ~VT_UNSIGNED) == VT_BYTE)) {
            /* XXX: move multiple string parsing in parser ? */
            while (tok == TOK_STR || tok == TOK_LSTR) {
                ts = (TokenSym *)tokc;
                /* compute maximum number of chars wanted */
                nb = ts->len;
                if (n >= 0 && nb > (n - array_length))
                    nb = n - array_length;
                if (!size_only) {
                    if (ts->len > nb)
                        warning("initializer-string for array is too long");
                    for(i=0;i<nb;i++) {
                        init_putv(t1, c + (array_length + i) * size1, 
                                  ts->str[i], 0);
                    }
                }
                array_length += nb;
                next();
            }
            /* only add trailing zero if enough storage (no
               warning in this case since it is standard) */
            if (n < 0 || array_length < n) {
                if (!size_only) {
                    init_putv(t1, c + (array_length * size1), 0, 0);
                }
                array_length++;
            }
        } else {
            index = 0;
            while (tok != '}') {
                decl_designator(t, c, &index, NULL, size_only);
                if (n >= 0 && index >= n)
                    error("index too large");
                /* must put zero in holes (note that doing it that way
                   ensures that it even works with designators) */
                if (!size_only && array_length < index) {
                    init_putz(t1, c + array_length * size1, 
                              (index - array_length) * size1);
                }
                index++;
                if (index > array_length)
                    array_length = index;
                /* special test for multi dimensional arrays (may not
                   be strictly correct if designators are used at the
                   same time) */
                if (index >= n && no_oblock)
                    break;
                if (tok == '}')
                    break;
                skip(',');
            }
        }
        if (!no_oblock)
            skip('}');
        /* put zeros at the end */
        if (!size_only && n >= 0 && array_length < n) {
            init_putz(t1, c + array_length * size1, 
                      (n - array_length) * size1);
        }
        /* patch type size if needed */
        if (n < 0)
            s->c = array_length;
    } else if ((t & VT_STRUCT) && tok == '{') {
        /* XXX: union needs only one init */
        next();
        s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT) | SYM_STRUCT);
        f = s->next;
        array_length = 0;
        index = 0;
        n = s->c;
        while (tok != '}') {
            decl_designator(t, c, NULL, &f, size_only);
            /* fill with zero between fields */
            index = f->c;
            if (!size_only && array_length < index) {
                init_putz(t, c + array_length, 
                          index - array_length);
            }
            index = index + type_size(f->t, &align1);
            if (index > array_length)
                array_length = index;
            if (tok == '}')
                break;
            skip(',');
            f = f->next;
        }
        /* put zeros at the end */
        if (!size_only && array_length < n) {
            init_putz(t, c + array_length, 
                      n - array_length);
        }
        skip('}');
    } else if (tok == '{') {
        next();
        decl_initializer(t, c, first, size_only);
        skip('}');
    } else if (size_only) {
        /* just skip expression */
        parlevel = 0;
        while ((parlevel > 0 || (tok != '}' && tok != ',')) && 
               tok != -1) {
            if (tok == '(')
                parlevel++;
            else if (tok == ')')
                parlevel--;
            next();
        }
    } else {
        init_putv(t, c, 0, 1);
    }
}

/* parse an initializer for type 't' if 'has_init' is true, and
   allocate space in local or global data space. The allocated address
   in returned */
int decl_initializer_alloc(int t, int has_init)
{
    int size, align, addr, tok1;
    int *init_str, init_len, level, *saved_macro_ptr;

    size = type_size(t, &align);
    /* If unknown size, we must evaluate it before
       evaluating initializers because
       initializers can generate global data too
       (e.g. string pointers or ISOC99 compound
       literals). It also simplifies local
       initializers handling */
    init_len = 0;
    init_str = NULL;
    saved_macro_ptr = NULL; /* avoid warning */
    tok1 = 0;
    if (size < 0) {
        if (!has_init) 
            error("unknown type size");
        /* get all init string */
        level = 0;
        while (level > 0 || (tok != ',' && tok != ';')) {
            if (tok < 0)
                error("unexpect end of file in initializer");
            tok_add2(&init_str, &init_len, tok, tokc);
            if (tok == '{')
                level++;
            else if (tok == '}') {
                if (level == 0)
                    break;
                level--;
            }
            next();
        }
        tok1 = tok;
        tok_add(&init_str, &init_len, -1);
        tok_add(&init_str, &init_len, 0);
        
        /* compute size */
        saved_macro_ptr = macro_ptr;
        macro_ptr = init_str;
        next();
        decl_initializer(t, 0, 1, 1);
        /* prepare second initializer parsing */
        macro_ptr = init_str;
        next();
        
        /* if still unknown size, error */
        size = type_size(t, &align);
        if (size < 0) 
            error("unknown type size");
    }
    if ((t & VT_VALMASK) == VT_LOCAL) {
        loc = (loc - size) & -align;
        addr = loc;
    } else {
        glo = (glo + align - 1) & -align;
        addr = glo;
        /* very important to increment global
           pointer at this time because
           initializers themselves can create new
           initializers */
        glo += size;
    }
    if (has_init) {
        decl_initializer(t, addr, 1, 0);
        /* restore parse state if needed */
        if (init_str) {
            free(init_str);
            macro_ptr = saved_macro_ptr;
            tok = tok1;
        }
    }
    return addr;
}


/* 'l' is VT_LOCAL or VT_CONST to define default storage type */
void decl(int l)
{
    int *a, t, b, v, u, addr, has_init, size, align;
    Sym *sym;
    
    while (1) {
        b = ist();
        if (!b) {
            /* skip redundant ';' */
            /* XXX: find more elegant solution */
            if (tok == ';') {
                next();
                continue;
            }
            /* special test for old K&R protos without explicit int
               type. Only accepted when defining global data */
            if (l == VT_LOCAL || tok < TOK_DEFINE)
                break;
            b = VT_INT;
        }
        if ((b & (VT_ENUM | VT_STRUCT)) && tok == ';') {
            /* we accept no variable after */
            next();
            continue;
        }
        while (1) { /* iterate thru each declaration */
            t = type_decl(&v, b, TYPE_DIRECT);
            if (tok == '{') {
                if (l == VT_LOCAL)
                    error("cannot use local functions");
                if (!(t & VT_FUNC))
                    expect("function definition");
                /* patch forward references */
                if ((sym = sym_find(v)) && (sym->t & VT_FORWARD)) {
                    greloc_patch(sym, ind);
                    sym->t = VT_CONST | t;
                } else {
                    /* put function address */
                    sym_push1(&global_stack, v, VT_CONST | t, ind);
                }
                funcname = get_tok_str(v, 0);
                /* push a dummy symbol to enable local sym storage */
                sym_push1(&local_stack, 0, 0, 0);
                /* define parameters */
                sym = sym_find((unsigned)t >> VT_STRUCT_SHIFT);
                /* XXX: the following is x86 dependant -> move it to
                   x86 code gen */
                addr = 8;
                /* if the function returns a structure, then add an
                   implicit pointer parameter */
                func_vt = sym->t;
                if (func_vt & VT_STRUCT) {
                    func_vc = addr;
                    addr += 4;
                }
                while (sym = sym->next) {
                    u = sym->t;
                    sym_push(sym->v & ~SYM_FIELD, 
                             u | VT_LOCAL | VT_LVAL, 
                             addr);
                    if (u & VT_STRUCT) {
#ifdef FUNC_STRUCT_PARAM_AS_PTR
                        /* structs are passed as pointer */
                        size = 4;
#else
                        /* structs are directly put on stack (x86
                           like) */
                        size = type_size(u, &align);
                        size = (size + 3) & ~3;
#endif
                    } else {
                        /* XXX: size will be different someday */
                        size = 4;
                    }
                    addr += size;
                }
                loc = 0;
                o(0xe58955); /* push   %ebp, mov    %esp, %ebp */
                a = (int *)oad(0xec81, 0); /* sub $xxx, %esp */
                rsym = 0;
                block(0, 0, 0, 0, 0);
                gsym(rsym);
                o(0xc3c9); /* leave, ret */
                *a = (-loc + 3) & -4; /* align local size to word & 
                                         save local variables */
                sym_pop(&label_stack, 0); /* reset label stack */
                sym_pop(&local_stack, 0); /* reset local stack */
                funcname = ""; /* for safety */
                func_vt = VT_VOID; /* for safety */
                break;
            } else {
                if (b & VT_TYPEDEF) {
                    /* save typedefed type */
                    sym_push(v, t | VT_TYPEDEF, 0);
                } else if (t & VT_FUNC) {
                    /* external function definition */
                    external_sym(v, t);
                } else {
                    /* not lvalue if array */
                    if (!(t & VT_ARRAY))
                        t |= VT_LVAL;
                    if (b & VT_EXTERN) {
                        /* external variable */
                        external_sym(v, t);
                    } else {
                        u = l;
                        if (t & VT_STATIC)
                            u = VT_CONST;
                        u |= t;
                        has_init = (tok == '=');
                        if (has_init)
                            next();
                        addr = decl_initializer_alloc(u, has_init);
                        if (l == VT_CONST) {
                            /* global scope: see if already defined */
                            sym = sym_find(v);
                            if (!sym)
                                goto do_def;
                            if (!is_compatible_types(sym->t, u))
                                error("incompatible types for redefinition of '%s'", 
                                      get_tok_str(v, 0));
                            if (!(sym->t & VT_FORWARD))
                                error("redefinition of '%s'", get_tok_str(v, 0));
                            greloc_patch(sym, addr);
                        } else {
                        do_def:
                            sym_push(v, u, addr);
                        }
                    }
                }
                if (tok != ',') {
                    skip(';');
                    break;
                }
                next();
            }
        }
    }
}

/* open a dynamic library so that its symbol are available for
   compiled programs */
void open_dll(char *libname)
{
    char buf[1024];
    void *h;

    snprintf(buf, sizeof(buf), "lib%s.so", libname);
    h = dlopen(buf, RTLD_GLOBAL | RTLD_LAZY);
    if (!h)
        error((char *)dlerror());
}

void reloc_external_syms(void)
{
    Sym *s, *s1;
    char *str;
    int addr;

    s = global_stack.top;
    while (s != NULL) {
        s1 = s->prev;
        if (s->t & VT_FORWARD) {
            /* if there is at least one relocation to do, then find it
               and patch it */
            if (s->c) {
                str = get_tok_str(s->v, 0);
                addr = (int)dlsym(NULL, str);
                if (!addr)
                    error("unresolved external reference '%s'", str);
                greloc_patch(s, addr);
            }
        }
        s = s1;
    }
}

/* output a binary file (for testing) */
void build_exe(char *filename)
{ 
    FILE *f;
    f = fopen(filename, "w");
    fwrite((void *)prog, 1, ind - prog, f);
    fclose(f);
}

int main(int argc, char **argv)
{
    Sym *s;
    int (*t)();
    char *p, *r, *outfile;
    int optind;

    include_paths[0] = "/usr/include";
    include_paths[1] = "/usr/lib/tcc";
    include_paths[2] = "/usr/local/lib/tcc";
    nb_include_paths = 3;

    /* add all tokens */
    tok_ident = TOK_IDENT;
    p = "int\0void\0char\0if\0else\0while\0break\0return\0for\0extern\0static\0unsigned\0goto\0do\0continue\0switch\0case\0const\0volatile\0long\0register\0signed\0auto\0inline\0restrict\0float\0double\0short\0struct\0union\0typedef\0default\0enum\0sizeof\0define\0include\0ifdef\0ifndef\0elif\0endif\0defined\0undef\0error\0line\0__LINE__\0__FILE__\0__DATE__\0__TIME__\0__VA_ARGS__\0__func__\0main\0";
    while (*p) {
        r = p;
        while (*r++);
        tok_alloc(p, r - p - 1);
        p = r;
    }

    /* standard defines */
    define_symbol("__STDC__");
#ifdef __i386__
    define_symbol("__i386__");
#endif
    
    optind = 1;
    outfile = NULL;
    while (1) {
        if (optind >= argc) {
        show_help:
            printf("tcc version 0.9.1 - Tiny C Compiler - Copyright (C) 2001 Fabrice Bellard\n" 
                   "usage: tcc [-Idir] [-Dsym] [-llib] infile [infile_arg...]\n");
            return 1;
        }
        r = argv[optind];
        if (r[0] != '-')
            break;
        optind++;
        if (r[1] == 'I') {
            if (nb_include_paths >= INCLUDE_PATHS_MAX)
                error("too many include paths");
            include_paths[nb_include_paths++] = r + 2;
        } else if (r[1] == 'D') {
            define_symbol(r + 2);
        } else if (r[1] == 'l') {
            open_dll(r + 2);
        } else if (r[1] == 'o') {
            /* currently, only for testing, so not documented */
            if (optind >= argc)
                goto show_help;
            outfile = argv[optind++];
        } else {
            fprintf(stderr, "invalid option -- '%s'\n", r);
            exit(1);
        }
    }
    
    filename = argv[optind];
    line_num = 1;
    funcname = "";
    file = fopen(filename, "r");
    if (!file) {
        perror(filename);
        exit(1);
    }
    include_stack_ptr = include_stack;
    ifdef_stack_ptr = ifdef_stack;

    glo = (int)malloc(DATA_SIZE);
    memset((void *)glo, 0, DATA_SIZE);
    prog = (int)malloc(TEXT_SIZE);
    vstack_ptr = vstack;
    anon_sym = 1 << (31 - VT_STRUCT_SHIFT); 
    ind = prog;
    inp();
    ch = '\n'; /* needed to parse correctly first preprocessor command */
    next();
    decl(VT_CONST);
    if (tok != -1)
        expect("declaration");
    reloc_external_syms();
    if (outfile) {
        build_exe(outfile);
        return 0;
    } else {
        s = sym_find(TOK_MAIN);
        if (!s)
            error("main() not defined");
        t = (int (*)())s->c;
#ifdef PROFILE
        return 1;
#else
        return (*t)(argc - optind, argv + optind);
#endif
    }
}