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[tinycc.git] / tcc.c

/*
 *  TCC - Tiny C Compiler
 * 
 *  Copyright (c) 2001, 2002 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 <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <math.h>
#include <unistd.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#ifndef WIN32
#include <sys/ucontext.h>
#include <sys/mman.h>
#endif
#include "elf.h"
#include "stab.h"
#ifndef CONFIG_TCC_STATIC
#include <dlfcn.h>
#endif

#include "libtcc.h"

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

/* target selection */
//#define TCC_TARGET_I386   /* i386 code generator */
//#define TCC_TARGET_IL     /* .NET CLI generator */

/* default target is I386 */
#if !defined(TCC_TARGET_I386) && !defined(TCC_TARGET_IL)
#define TCC_TARGET_I386
#endif

#if !defined(WIN32) && !defined(TCC_UCLIBC) && !defined(TCC_TARGET_IL)
#define CONFIG_TCC_BCHECK /* enable bound checking code */
#endif

#ifndef CONFIG_TCC_PREFIX
#define CONFIG_TCC_PREFIX "/usr/local"
#endif

/* path to find crt1.o, crti.o and crtn.o. Only needed when generating
   executables or dlls */
#define CONFIG_TCC_CRT_PREFIX "/usr/lib"

/* amount of virtual memory associated to a section (currently, we do
   not realloc them) */
#define SECTION_VSIZE       (1024 * 1024)

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

#define TOK_HASH_SIZE       2048 /* must be a power of two */
#define TOK_ALLOC_INCR      512  /* must be a power of two */
#define SYM_HASH_SIZE       1031
#define ELF_SYM_HASH_SIZE      2048
#define ELF_DYNSYM_HASH_SIZE   32

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

/* constant value */
typedef union CValue {
    long double ld;
    double d;
    float f;
    int i;
    unsigned int ui;
    unsigned int ul; /* address (should be unsigned long on 64 bit cpu) */
    long long ll;
    unsigned long long ull;
    struct TokenSym *ts;
    struct Sym *sym;
    void *ptr;
    int tab[1];
} CValue;

/* value on stack */
typedef struct SValue {
    int t;      /* type */
    unsigned short r;      /* register + flags */
    unsigned short r2;     /* second register, used for 'long long'
                              type. If not used, set to VT_CONST */
    CValue c;              /* constant, if VT_CONST */
} SValue;

/* symbol management */
typedef struct Sym {
    int v;    /* symbol token */
    int t;    /* associated type */
    int r;    /* associated register */
    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;

/* section definition */
/* XXX: use directly ELF structure for parameters ? */
/* special flag to indicate that the section should not be linked to
   the other ones */
#define SHF_PRIVATE 0x80000000

typedef struct Section {
    unsigned long data_offset; /* current data offset */
    unsigned char *data;       /* section data */
    int sh_name;             /* elf section name (only used during output) */
    int sh_num;              /* elf section number */
    int sh_type;             /* elf section type */
    int sh_flags;            /* elf section flags */
    int sh_info;             /* elf section info */
    int sh_addralign;        /* elf section alignment */
    int sh_entsize;          /* elf entry size */
    unsigned long sh_size;   /* section size (only used during output) */
    unsigned long sh_addr;      /* address at which the section is relocated */
    unsigned long sh_offset;      /* address at which the section is relocated */
    struct Section *link;    /* link to another section */
    struct Section *reloc;   /* corresponding section for relocation, if any */
    struct Section *hash;     /* hash table for symbols */
    struct Section *next;
    char name[64];           /* section name */
} Section;

typedef struct DLLReference {
    int level;
    char name[1];
} DLLReference;

/* GNUC attribute definition */
typedef struct AttributeDef {
    int aligned;
    Section *section;
    unsigned char func_call; /* FUNC_CDECL or FUNC_STDCALL */
} AttributeDef;

#define SYM_STRUCT     0x40000000 /* struct/union/enum symbol space */
#define SYM_FIELD      0x20000000 /* struct/union field symbol space */
#define SYM_FIRST_ANOM (1 << (31 - VT_STRUCT_SHIFT)) /* first anonymous sym */

/* stored in 'Sym.c' field */
#define FUNC_NEW       1 /* ansi function prototype */
#define FUNC_OLD       2 /* old function prototype */
#define FUNC_ELLIPSIS  3 /* ansi function prototype with ... */

/* stored in 'Sym.r' field */
#define FUNC_CDECL     0 /* standard c call */
#define FUNC_STDCALL   1 /* pascal c call */

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

/* field 'Sym.t' for labels */
#define LABEL_FORWARD  1 /* label is forward defined */

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

#define IO_BUF_SIZE 8192

typedef struct BufferedFile {
    unsigned char *buf_ptr;
    unsigned char *buf_end;
    int fd;
    int line_num;    /* current line number - here to simply code */
    char filename[1024];    /* current filename - here to simplify code */
    unsigned char buffer[IO_BUF_SIZE + 1]; /* extra size for CH_EOB char */
} BufferedFile;

#define CH_EOB   0       /* end of buffer or '\0' char in file */
#define CH_EOF   (-1)   /* end of file */

/* parsing state (used to save parser state to reparse part of the
   source several times) */
typedef struct ParseState {
    int *macro_ptr;
    int line_num;
    int tok;
    CValue tokc;
} ParseState;

/* used to record tokens */
typedef struct TokenString {
    int *str;
    int len;
    int last_line_num;
} TokenString;

/* parser */
struct BufferedFile *file;
int ch, ch1, tok, tok1;
CValue tokc, tok1c;
int return_linefeed; /* if true, line feed is returned as a token */

/* sections */
Section **sections;
int nb_sections; /* number of sections, including first dummy section */
Section *text_section, *data_section, *bss_section; /* predefined sections */
Section *cur_text_section; /* current section where function code is
                              generated */
/* bound check related sections */
Section *bounds_section; /* contains global data bound description */
Section *lbounds_section; /* contains local data bound description */
/* symbol sections */
Section *symtab_section, *strtab_section;
/* temporary dynamic symbol sections (for dll loading) */
Section *dynsymtab_section, *dynstrtab_section;
/* exported dynamic symbol section */
Section *dynsym;
/* got handling */
Section *got;
unsigned long *got_offsets;
int nb_got_offsets;
int nb_plt_entries;


/* array of all loaded dlls (including those referenced by loaded
   dlls) */
DLLReference **loaded_dlls;
int nb_loaded_dlls;

/* debug sections */
Section *stab_section, *stabstr_section;

char **library_paths;
int nb_library_paths;

/* loc : local variable index
   ind : output code index
   rsym: return symbol
   anon_sym: anonymous symbol index
*/
int rsym, anon_sym,
    prog, ind, loc, const_wanted;
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 last_line_num, last_ind, func_ind; /* debug last line number and pc */
int tok_ident;
TokenSym **table_ident;
TokenSym *hash_ident[TOK_HASH_SIZE];
char token_buf[STRING_MAX_SIZE + 1];
char *funcname;
SymStack define_stack, global_stack, local_stack, label_stack;

SValue vstack[VSTACK_SIZE], *vtop;
int *macro_ptr, *macro_ptr_allocated;
BufferedFile *include_stack[INCLUDE_STACK_SIZE], **include_stack_ptr;
int ifdef_stack[IFDEF_STACK_SIZE], *ifdef_stack_ptr;
char **include_paths;
int nb_include_paths;
int char_pointer_type;
int func_old_type;

/* compile with debug symbol (and use them if error during execution) */
int do_debug = 0;

/* compile with built-in memory and bounds checker */
int do_bounds_check = 0;

/* display benchmark infos */
int do_bench = 0;
int total_lines;
int total_bytes;

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

/* use Tiny C extensions */
int tcc_ext = 1;

/* if true, static linking is performed */
int static_link = 0;

/* give the path of the tcc libraries */
static const char *tcc_lib_path = CONFIG_TCC_PREFIX "/lib/tcc";

struct TCCState {
    int output_type;
};

/* The current value can be: */
#define VT_VALMASK   0x00ff
#define VT_CONST     0x00f0  /* constant in vc 
                              (must be first non register value) */
#define VT_LLOCAL    0x00f1  /* lvalue, offset on stack */
#define VT_LOCAL     0x00f2  /* offset on stack */
#define VT_CMP       0x00f3  /* the value is stored in processor flags (in vc) */
#define VT_JMP       0x00f4  /* value is the consequence of jmp true (even) */
#define VT_JMPI      0x00f5  /* value is the consequence of jmp false (odd) */
#define VT_LVAL      0x0100  /* var is an lvalue */
#define VT_SYM       0x0200  /* a symbol value is added */
#define VT_MUSTCAST  0x0400  /* value must be casted to be correct (used for
                                char/short stored in integer registers) */
#define VT_MUSTBOUND 0x0800  /* bound checking must be done before
                                dereferencing value */
#define VT_BOUNDED   0x8000  /* value is bounded. The address of the
                                bounding function call point is in vc */
#define VT_LVAL_BYTE     0x1000  /* lvalue is a byte */
#define VT_LVAL_SHORT    0x2000  /* lvalue is a short */
#define VT_LVAL_UNSIGNED 0x4000  /* lvalue is unsigned */
#define VT_LVAL_TYPE     (VT_LVAL_BYTE | VT_LVAL_SHORT | VT_LVAL_UNSIGNED)

/* types */
#define VT_STRUCT_SHIFT 12   /* structure/enum name shift (20 bits left) */

#define VT_INT        0  /* integer type */
#define VT_BYTE       1  /* signed byte type */
#define VT_SHORT      2  /* short type */
#define VT_VOID       3  /* void type */
#define VT_PTR        4  /* pointer */
#define VT_ENUM       5  /* enum definition */
#define VT_FUNC       6  /* function type */
#define VT_STRUCT     7  /* struct/union definition */
#define VT_FLOAT      8  /* IEEE float */
#define VT_DOUBLE     9  /* IEEE double */
#define VT_LDOUBLE   10  /* IEEE long double */
#define VT_BOOL      11  /* ISOC99 boolean type */
#define VT_LLONG     12  /* 64 bit integer */
#define VT_LONG      13  /* long integer (NEVER USED as type, only
                            during parsing) */
#define VT_BTYPE      0x000f /* mask for basic type */
#define VT_UNSIGNED   0x0010  /* unsigned type */
#define VT_ARRAY      0x0020  /* array type (also has VT_PTR) */
#define VT_BITFIELD   0x0040  /* bitfield modifier */

/* storage */
#define VT_EXTERN  0x00000080  /* extern definition */
#define VT_STATIC  0x00000100  /* static variable */
#define VT_TYPEDEF 0x00000200  /* typedef definition */

/* type mask (except storage) */
#define VT_TYPE    (~(VT_EXTERN | VT_STATIC | VT_TYPEDEF))

/* 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_UDIV  0xb0 /* unsigned division */
#define TOK_UMOD  0xb1 /* unsigned modulo */
#define TOK_PDIV  0xb2 /* fast division with undefined rounding for pointers */
#define TOK_CINT   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_CFLOAT   0xb9 /* float constant */
#define TOK_LINENUM  0xba /* line number info */
#define TOK_CDOUBLE  0xc0 /* double constant */
#define TOK_CLDOUBLE 0xc1 /* long double constant */
#define TOK_UMULL    0xc2 /* unsigned 32x32 -> 64 mul */
#define TOK_ADDC1    0xc3 /* add with carry generation */
#define TOK_ADDC2    0xc4 /* add with carry use */
#define TOK_SUBC1    0xc5 /* add with carry generation */
#define TOK_SUBC2    0xc6 /* add with carry use */
#define TOK_CUINT    0xc8 /* unsigned int constant */
#define TOK_CLLONG   0xc9 /* long long constant */
#define TOK_CULLONG  0xca /* unsigned long long constant */
#define TOK_ARROW    0xcb
#define TOK_DOTS     0xcc /* three dots */
#define TOK_SHR      0xcd /* unsigned shift right */

#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

#define TOK_EOF       (-1)  /* end of file */
#define TOK_LINEFEED  10    /* line feed */

/* 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___SIGNED__, /* gcc keyword */
    TOK_AUTO,
    TOK_INLINE,
    TOK___INLINE__, /* gcc keyword */
    TOK_RESTRICT,

    /* unsupported type */
    TOK_FLOAT,
    TOK_DOUBLE,
    TOK_BOOL,

    TOK_SHORT,
    TOK_STRUCT,
    TOK_UNION,
    TOK_TYPEDEF,
    TOK_DEFAULT,
    TOK_ENUM,
    TOK_SIZEOF,
    TOK___ATTRIBUTE__,
    
    /* 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,
#define DEF(id, str) id,
#include "tcctok.h"
#undef DEF
};

char *tcc_keywords = 
"int\0void\0char\0if\0else\0while\0break\0return\0for\0extern\0static\0"
"unsigned\0goto\0do\0continue\0switch\0case\0const\0volatile\0long\0"
"register\0signed\0__signed__\0auto\0inline\0__inline__\0restrict\0"
"float\0double\0_Bool\0short\0struct\0union\0typedef\0default\0enum\0"
"sizeof\0__attribute__\0"
/* the following are not keywords. They are included to ease parsing */
"define\0include\0ifdef\0ifndef\0elif\0endif\0"
"defined\0undef\0error\0line\0"
"__LINE__\0__FILE__\0__DATE__\0__TIME__\0__VA_ARGS__\0"
"__func__\0main\0"
/* builtin functions */
#define DEF(id, str) str "\0"
#include "tcctok.h"
#undef DEF
;

#ifdef WIN32
#define snprintf _snprintf
#endif

#if defined(WIN32) || defined(TCC_UCLIBC)
/* currently incorrect */
long double strtold(const char *nptr, char **endptr)
{
    return (long double)strtod(nptr, endptr);
}
float strtof(const char *nptr, char **endptr)
{
    return (float)strtod(nptr, endptr);
}
#else
/* XXX: need to define this to use them in non ISOC99 context */
extern float strtof (const char *__nptr, char **__endptr);
extern long double strtold (const char *__nptr, char **__endptr);
#endif

static char *pstrcpy(char *buf, int buf_size, const char *s);
static char *pstrcat(char *buf, int buf_size, const char *s);

void sum(int l);
void next(void);
void next_nomacro(void);
int expr_const(void);
void expr_eq(void);
void gexpr(void);
void decl(int l);
void decl_initializer(int t, Section *sec, unsigned long c, int first, int size_only);
void decl_initializer_alloc(int t, AttributeDef *ad, int r, int has_init,
                            int v, int scope);
int gv(int rc);
void gv2(int rc1, int rc2);
void move_reg(int r, int s);
void save_regs(int n);
void save_reg(int r);
void vpop(void);
void vswap(void);
void vdup(void);
int get_reg(int rc);

void macro_subst(TokenString *tok_str, 
                 Sym **nested_list, int *macro_str);
int save_reg_forced(int r);
void gen_op(int op);
void force_charshort_cast(int t);
void gen_cast(int t);
void vstore(void);
Sym *sym_find(int v);
Sym *sym_push(int v, int t, int r, int c);

/* type handling */
int type_size(int t, int *a);
int pointed_type(int t);
int pointed_size(int t);
int is_compatible_types(int t1, int t2);
int parse_btype(int *type_ptr, AttributeDef *ad);
int type_decl(AttributeDef *ad, int *v, int t, int td);

void error(const char *fmt, ...);
void rt_error(unsigned long pc, const char *fmt, ...);
void vpushi(int v);
void vset(int t, int r, int v);
void type_to_str(char *buf, int buf_size, 
                 int t, const char *varstr);
char *get_tok_str(int v, CValue *cv);
Sym *external_sym(int v, int u, int r);
static Sym *get_sym_ref(int t, Section *sec, 
                        unsigned long offset, unsigned long size);

/* section generation */
static void *section_ptr(Section *sec, unsigned long size);
static void *section_ptr_add(Section *sec, unsigned long size);
void put_extern_sym(Sym *sym, Section *section, unsigned long value);
void greloc(Section *s, Sym *sym, unsigned long addr, int type);
static int put_elf_str(Section *s, const char *sym);
static int put_elf_sym(Section *s, 
                       unsigned long value, unsigned long size,
                       int info, int other, int shndx, const char *name);
static void put_elf_reloc(Section *symtab, Section *s, unsigned long offset,
                          int type, int symbol);
static void put_stabs(const char *str, int type, int other, int desc, 
                      unsigned long value);
static void put_stabs_r(const char *str, int type, int other, int desc, 
                        unsigned long value, Section *sec, int sym_index);
static void put_stabn(int type, int other, int desc, int value);
static void put_stabd(int type, int other, int desc);
static int tcc_add_dll(TCCState *s, const char *filename, int flags);

#define AFF_PRINT_ERROR     0x0001 /* print error if file not found */
#define AFF_REFERENCED_DLL  0x0002 /* load a referenced dll from another dll */
static int tcc_add_file_internal(TCCState *s, const char *filename, int flags);

/* true if float/double/long double type */
static inline int is_float(int t)
{
    int bt;
    bt = t & VT_BTYPE;
    return bt == VT_LDOUBLE || bt == VT_DOUBLE || bt == VT_FLOAT;
}

#ifdef TCC_TARGET_I386
#include "i386-gen.c"
#endif
#ifdef TCC_TARGET_IL
#include "il-gen.c"
#endif

#ifdef CONFIG_TCC_STATIC

#define RTLD_LAZY       0x001
#define RTLD_NOW        0x002
#define RTLD_GLOBAL     0x100

/* dummy function for profiling */
void *dlopen(const char *filename, int flag)
{
    return NULL;
}

const char *dlerror(void)
{
    return "error";
}

typedef struct TCCSyms {
    char *str;
    void *ptr;
} TCCSyms;

#define TCCSYM(a) { #a, &a, },

/* add the symbol you want here if no dynamic linking is done */
static TCCSyms tcc_syms[] = {
    TCCSYM(printf)
    TCCSYM(fprintf)
    TCCSYM(fopen)
    TCCSYM(fclose)
    { NULL, NULL },
};

void *dlsym(void *handle, const char *symbol)
{
    TCCSyms *p;
    p = tcc_syms;
    while (p->str != NULL) {
        if (!strcmp(p->str, symbol))
            return p->ptr;
        p++;
    }
    return NULL;
}

#endif

/********************************************************/

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

/* copy a string and truncate it. */
static char *pstrcpy(char *buf, int buf_size, const char *s)
{
    char *q, *q_end;
    int c;

    if (buf_size > 0) {
        q = buf;
        q_end = buf + buf_size - 1;
        while (q < q_end) {
            c = *s++;
            if (c == '\0')
                break;
            *q++ = c;
        }
        *q = '\0';
    }
    return buf;
}

/* strcat and truncate. */
static char *pstrcat(char *buf, int buf_size, const char *s)
{
    int len;
    len = strlen(buf);
    if (len < buf_size) 
        pstrcpy(buf + len, buf_size - len, s);
    return buf;
}

static void dynarray_add(void ***ptab, int *nb_ptr, void *data)
{
    int nb, nb_alloc;
    void **pp;
    
    nb = *nb_ptr;
    pp = *ptab;
    /* every power of two we double array size */
    if ((nb & (nb - 1)) == 0) {
        if (!nb)
            nb_alloc = 1;
        else
            nb_alloc = nb * 2;
        pp = realloc(pp, nb_alloc * sizeof(void *));
        if (!pp)
            error("memory full");
        *ptab = pp;
    }
    pp[nb++] = data;
    *nb_ptr = nb;
}

Section *new_section(const char *name, int sh_type, int sh_flags)
{
    Section *sec;
    void *data;

    sec = malloc(sizeof(Section));
    if (!sec)
        error("memory full");
    memset(sec, 0, sizeof(Section));
    pstrcpy(sec->name, sizeof(sec->name), name);
    sec->sh_type = sh_type;
    sec->sh_flags = sh_flags;
    switch(sh_type) {
    case SHT_HASH:
    case SHT_REL:
    case SHT_DYNSYM:
    case SHT_SYMTAB:
    case SHT_DYNAMIC:
        sec->sh_addralign = 4;
        break;
    case SHT_STRTAB:
        sec->sh_addralign = 1;
        break;
    default:
        sec->sh_addralign = 32; /* default conservative alignment */
        break;
    }
#ifdef WIN32
    /* XXX: currently, a single malloc */
    data = malloc(SECTION_VSIZE);
    if (data == NULL)
        error("could not alloc section '%s'", name);
#else
    data = mmap(NULL, SECTION_VSIZE, 
                PROT_EXEC | PROT_READ | PROT_WRITE, 
                MAP_PRIVATE | MAP_ANONYMOUS, 
                -1, 0);
    if (data == (void *)(-1))
        error("could not mmap section '%s'", name);
#endif
    sec->data = data;
    sec->data_offset = 0;

        /* only add section if not private */
    if (!(sh_flags & SHF_PRIVATE)) {
        sec->sh_num = nb_sections;
        dynarray_add((void ***)&sections, &nb_sections, sec);
    }
    return sec;
}

/* reserve at least 'size' bytes in section 'sec' from sec->data_offset */
static void *section_ptr(Section *sec, unsigned long size)
{
    return sec->data + sec->data_offset;
}

static void *section_ptr_add(Section *sec, unsigned long size)
{
    void *ptr;
    ptr = sec->data + sec->data_offset;
    sec->data_offset += size;
    return ptr;
}

/* return a reference to a section, and create it if it does not
   exists */
Section *find_section(const char *name)
{
    Section *sec;
    int i;
    for(i = 1; i < nb_sections; i++) {
        sec = sections[i];
        if (!strcmp(name, sec->name)) 
            return sec;
    }
    /* sections are created as PROGBITS */
    return new_section(name, SHT_PROGBITS, SHF_ALLOC);
}

/* add a new relocation entry to symbol 'sym' in section 's' */
void greloc(Section *s, Sym *sym, unsigned long offset, int type)
{
    if (!sym->c) 
        put_extern_sym(sym, NULL, 0);
    /* now we can add ELF relocation info */
    put_elf_reloc(symtab_section, s, offset, type, sym->c);
}

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

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

static inline int toup(int c)
{
    if (ch >= 'a' && ch <= 'z')
        return ch - 'a' + 'A';
    else
        return ch;
}

void printline(void)
{
    BufferedFile **f;

    if (file) {
        for(f = include_stack; f < include_stack_ptr; f++)
            fprintf(stderr, "In file included from %s:%d:\n", 
                    (*f)->filename, (*f)->line_num);
        if (file->line_num > 0) {
            fprintf(stderr, "%s:%d: ", file->filename, file->line_num);
        } else {
            fprintf(stderr, "%s: ", file->filename);
        }
    } else {
        fprintf(stderr, "tcc: ");
    }
}

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 *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    printline();
    fprintf(stderr, "warning: ");
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    va_end(ap);
}

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

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

TokenSym *tok_alloc(const 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 * 263 +  ((unsigned char *)str)[i]) & (TOK_HASH_SIZE - 1);

    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);
    }

    if (tok_ident >= SYM_FIRST_ANOM) 
        error("memory full");

    /* 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, CValue *cv)
{
    static char buf[STRING_MAX_SIZE + 1];
    TokenSym *ts;
    char *p;
    int i;

    if (v == TOK_CINT || v == TOK_CUINT) {
        sprintf(buf, "%u", cv->ui);
        return buf;
    } else if (v == TOK_CCHAR || v == TOK_LCHAR) {
        p = buf;
        *p++ = '\'';
        add_char(&p, cv->i);
        *p++ = '\'';
        *p = '\0';
        return buf;
    } else if (v == TOK_STR || v == TOK_LSTR) {
        ts = cv->ts;
        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 if (v >= SYM_FIRST_ANOM) {
        /* special name for anonymous symbol */
        sprintf(buf, "L.%u", v - SYM_FIRST_ANOM);
        return buf;
    } 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;
}

#define HASH_SYM(v) ((unsigned)(v) % SYM_HASH_SIZE)

/* 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[HASH_SYM(v)];
    while (s) {
        if (s->v == v)
            return s;
        s = s->hash_next;
    }
    return NULL;
}

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 */
    if (v) {
        ps = &st->hash[HASH_SYM(v)];
        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 r, int c)
{
    Sym *s;
    if (local_stack.top)
        s = sym_push1(&local_stack, v, t, c);
    else
        s = sym_push1(&global_stack, v, t, c);
    s->r = r;
    return s;
}

/* 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, except if symbol was freed (only
           used for #undef symbols) */
        if (s->v)
            st->hash[HASH_SYM(s->v)] = s->hash_next;
        free(s);
        s = ss;
    }
    st->top = b;
}

/* undefined a hashed symbol (used for #undef). Its name is set to
   zero */
void sym_undef(SymStack *st, Sym *s)
{
    Sym **ss;
    ss = &st->hash[HASH_SYM(s->v)];
    while (*ss != NULL) {
        if (*ss == s)
            break;
        ss = &(*ss)->hash_next;
    }
    *ss = s->hash_next;
    s->v = 0;
}

/* I/O layer */

BufferedFile *tcc_open(const char *filename)
{
    int fd;
    BufferedFile *bf;

    fd = open(filename, O_RDONLY);
    if (fd < 0)
        return NULL;
    bf = malloc(sizeof(BufferedFile));
    if (!bf) {
        close(fd);
        return NULL;
    }
    bf->fd = fd;
    bf->buf_ptr = bf->buffer;
    bf->buf_end = bf->buffer;
    bf->buffer[0] = CH_EOB; /* put eob symbol */
    pstrcpy(bf->filename, sizeof(bf->filename), filename);
    bf->line_num = 1;
    //    printf("opening '%s'\n", filename);
    return bf;
}

void tcc_close(BufferedFile *bf)
{
    total_lines += bf->line_num;
    close(bf->fd);
    free(bf);
}

/* read one char. MUST call tcc_fillbuf if CH_EOB is read */
#define TCC_GETC(bf) (*(bf)->buf_ptr++)

/* fill input buffer and return next char */
int tcc_getc_slow(BufferedFile *bf)
{
    int len;
    /* only tries to read if really end of buffer */
    if (bf->buf_ptr >= bf->buf_end) {
        if (bf->fd != -1) {
            len = read(bf->fd, bf->buffer, IO_BUF_SIZE);
            if (len < 0)
                len = 0;
        } else {
            len = 0;
        }
        total_bytes += len;
        bf->buf_ptr = bf->buffer;
        bf->buf_end = bf->buffer + len;
        *bf->buf_end = CH_EOB;
    }
    if (bf->buf_ptr < bf->buf_end) {
        return *bf->buf_ptr++;
    } else {
        bf->buf_ptr = bf->buf_end;
        return CH_EOF;
    }
}

/* no need to put that inline */
void handle_eob(void)
{
    for(;;) {
        ch1 = tcc_getc_slow(file);
        if (ch1 != CH_EOF)
            return;
        
        if (include_stack_ptr == include_stack)
            return;
        /* add end of include file debug info */
        if (do_debug) {
            put_stabd(N_EINCL, 0, 0);
        }
        /* pop include stack */
        tcc_close(file);
        include_stack_ptr--;
        file = *include_stack_ptr;
    }
}

/* read next char from current input file */
static inline void inp(void)
{
    ch1 = TCC_GETC(file);
    /* end of buffer/file handling */
    if (ch1 == CH_EOB)
        handle_eob();
    if (ch1 == '\n')
        file->line_num++;
    //    printf("ch1=%c 0x%x\n", ch1, ch1);
}

/* input with '\\n' handling */
static inline void minp(void)
{
 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(void)
{
    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(void)
{
    while (ch == ' ' || ch == '\t')
        cinp();
}

/* skip block of text until #else, #elif or #endif. skip also pairs of
   #if/#endif */
void preprocess_skip(void)
{
    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--;
        }
    }
}

/* ParseState handling */

/* XXX: currently, no include file info is stored. Thus, we cannot display
   accurate messages if the function or data definition spans multiple
   files */

/* save current parse state in 's' */
void save_parse_state(ParseState *s)
{
    s->line_num = file->line_num;
    s->macro_ptr = macro_ptr;
    s->tok = tok;
    s->tokc = tokc;
}

/* restore parse state from 's' */
void restore_parse_state(ParseState *s)
{
    file->line_num = s->line_num;
    macro_ptr = s->macro_ptr;
    tok = s->tok;
    tokc = s->tokc;
}

/* return the number of additionnal 'ints' necessary to store the
   token */
static inline int tok_ext_size(int t)
{
    switch(t) {
        /* 4 bytes */
    case TOK_CINT:
    case TOK_CUINT:
    case TOK_CCHAR:
    case TOK_LCHAR:
    case TOK_STR:
    case TOK_LSTR:
    case TOK_CFLOAT:
    case TOK_LINENUM:
        return 1;
    case TOK_CDOUBLE:
    case TOK_CLLONG:
    case TOK_CULLONG:
        return 2;
    case TOK_CLDOUBLE:
        return LDOUBLE_SIZE / 4;
    default:
        return 0;
    }
}

/* token string handling */

static inline void tok_str_new(TokenString *s)
{
    s->str = NULL;
    s->len = 0;
    s->last_line_num = -1;
}

static void tok_str_add(TokenString *s, int t)
{
    int len, *str;

    len = s->len;
    str = s->str;
    if ((len & 63) == 0) {
        str = realloc(str, (len + 64) * sizeof(int));
        if (!str)
            return;
        s->str = str;
    }
    str[len++] = t;
    s->len = len;
}

static void tok_str_add2(TokenString *s, int t, CValue *cv)
{
    int n, i;
    tok_str_add(s, t);
    n = tok_ext_size(t);
    for(i=0;i<n;i++)
        tok_str_add(s, cv->tab[i]);
}

/* add the current parse token in token string 's' */
static void tok_str_add_tok(TokenString *s)
{
    CValue cval;

    /* save line number info */
    if (file->line_num != s->last_line_num) {
        s->last_line_num = file->line_num;
        cval.i = s->last_line_num;
        tok_str_add2(s, TOK_LINENUM, &cval);
    }
    tok_str_add2(s, tok, &tokc);
}

/* get a token from an integer array and increment pointer accordingly */
static int tok_get(int **tok_str, CValue *cv)
{
    int *p, t, n, i;

    p = *tok_str;
    t = *p++;
    n = tok_ext_size(t);
    for(i=0;i<n;i++)
        cv->tab[i] = *p++;
    *tok_str = p;
    return t;
}

/* eval an expression for #if/#elif */
int expr_preprocess(void)
{
    int c, t;
    TokenString str;
    
    tok_str_new(&str);
    while (tok != TOK_LINEFEED && tok != TOK_EOF) {
        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_CINT;
            tokc.i = c;
        } else if (tok >= TOK_IDENT) {
            /* if undefined macro */
            tok = TOK_CINT;
            tokc.i = 0;
        }
        tok_str_add_tok(&str);
    }
    tok_str_add(&str, -1); /* simulate end of file */
    tok_str_add(&str, 0);
    /* now evaluate C constant expression */
    macro_ptr = str.str;
    next();
    c = expr_const();
    macro_ptr = NULL;
    free(str.str);
    return c != 0;
}

#if defined(DEBUG) || defined(PP_DEBUG)
void tok_print(int *str)
{
    int t;
    CValue cval;

    while (1) {
        t = tok_get(&str, &cval);
        if (!t)
            break;
        printf(" %s", get_tok_str(t, &cval));
    }
    printf("\n");
}
#endif

/* parse after #define */
void parse_define(void)
{
    Sym *s, *first, **ps;
    int v, t, varg, is_vaargs;
    TokenString str;
    
    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 != ')') {
            varg = tok;
            next_nomacro();
            is_vaargs = 0;
            if (varg == TOK_DOTS) {
                varg = TOK___VA_ARGS__;
                is_vaargs = 1;
            } else if (tok == TOK_DOTS && gnu_ext) {
                is_vaargs = 1;
                next_nomacro();
            }
            if (varg < TOK_IDENT)
                error("badly punctuated parameter list");
            s = sym_push1(&define_stack, varg | SYM_FIELD, is_vaargs, 0);
            *ps = s;
            ps = &s->next;
            if (tok != ',')
                break;
            next_nomacro();
        }
        t = MACRO_FUNC;
    }
    tok_str_new(&str);
    while (1) {
        skip_spaces();
        if (ch == '\n' || ch == -1)
            break;
        next_nomacro();
        tok_str_add2(&str, tok, &tokc);
    }
    tok_str_add(&str, 0);
#ifdef PP_DEBUG
    printf("define %s %d: ", get_tok_str(v, NULL), t);
    tok_print(str.str);
#endif
    s = sym_push1(&define_stack, v, t, (int)str.str);
    s->next = first;
}

void preprocess(void)
{
    int size, i, c;
    char buf[1024], *q, *p;
    char buf1[1024];
    BufferedFile *f;
    Sym *s;

    return_linefeed = 1; /* linefeed will be returned as a token */
    cinp();
    next_nomacro();
 redo:
    if (tok == TOK_DEFINE) {
        next_nomacro();
        parse_define();
    } else if (tok == TOK_UNDEF) {
        next_nomacro();
        s = sym_find1(&define_stack, tok);
        /* undefine symbol by putting an invalid name */
        if (s)
            sym_undef(&define_stack, s);
    } 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");
            pstrcpy(buf, sizeof(buf), get_tok_str(tok, &tokc));
            c = '\"';
        }
        /* eat all spaces and comments after include */
        /* XXX: slightly incorrect */
        while (ch1 != '\n' && ch1 != -1)
            inp();

        if (include_stack_ptr >= include_stack + INCLUDE_STACK_SIZE)
            error("memory full");
        if (c == '\"') {
            /* first search in current dir if "header.h" */
            size = 0;
            p = strrchr(file->filename, '/');
            if (p) 
                size = p + 1 - file->filename;
            if (size > sizeof(buf1) - 1)
                size = sizeof(buf1) - 1;
            memcpy(buf1, file->filename, size);
            buf1[size] = '\0';
            pstrcat(buf1, sizeof(buf1), buf);
            f = tcc_open(buf1);
            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 = tcc_open(buf1);
            if (f)
                goto found;
        }
        error("include file '%s' not found", buf);
        f = NULL;
    found:
        /* push current file in stack */
        /* XXX: fix current line init */
        *include_stack_ptr++ = file;
        file = f;
        /* add include file debug info */
        if (do_debug) {
            put_stabs(file->filename, N_BINCL, 0, 0, 0);
        }
        ch = '\n';
        goto the_end;
    } 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)
            error("#else without matching #if");
        if (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)
            error("#elif without matching #if");
        c = ifdef_stack_ptr[-1];
        if (c > 1)
            error("#elif after #else");
        /* last #if/#elif expression was true: we skip */
        if (c == 1)
            goto skip;
        c = expr_preprocess();
        ifdef_stack_ptr[-1] = c;
    test_skip:
        if (!(c & 1)) {
        skip:
            preprocess_skip();
            goto redo;
        }
    } else if (tok == TOK_ENDIF) {
        if (ifdef_stack_ptr == ifdef_stack)
            error("#endif without matching #if");
        ifdef_stack_ptr--;
    } else if (tok == TOK_LINE) {
        next();
        if (tok != TOK_CINT)
            error("#line");
        file->line_num = tokc.i;
        skip_spaces();
        if (ch != '\n') {
            next();
            if (tok != TOK_STR)
                error("#line");
            pstrcpy(file->filename, sizeof(file->filename), 
                    get_tok_str(tok, &tokc));
        }
    } else if (tok == TOK_ERROR) {
        error("#error");
    }
    /* ignore other preprocess commands or #! for C scripts */
    while (tok != TOK_LINEFEED && tok != TOK_EOF)
        next_nomacro();
 the_end:
    return_linefeed = 0;
}

/* read a number in base b */
static int getn(int 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 */
static int getq(void)
{
    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 if (ch == 'e' && gnu_ext)
                c = 27;
            else if (ch == '\'' || ch == '\"' || ch == '\\' || ch == '?')
                c = ch;
            else
                error("invalid escaped char");
            minp();
        }
    }
    return c;
}

/* we use 64 bit numbers */
#define BN_SIZE 2

/* bn = (bn << shift) | or_val */
void bn_lshift(unsigned int *bn, int shift, int or_val)
{
    int i;
    unsigned int v;
    for(i=0;i<BN_SIZE;i++) {
        v = bn[i];
        bn[i] = (v << shift) | or_val;
        or_val = v >> (32 - shift);
    }
}

void bn_zero(unsigned int *bn)
{
    int i;
    for(i=0;i<BN_SIZE;i++) {
        bn[i] = 0;
    }
}

void parse_number(void)
{
    int b, t, shift, frac_bits, s, exp_val;
    char *q;
    unsigned int bn[BN_SIZE];
    double d;

    /* number */
    q = token_buf;
    t = ch;
    cinp();
    *q++ = t;
    b = 10;
    if (t == '.') {
        /* special dot handling */
        if (ch >= '0' && ch <= '9') {
            goto float_frac_parse;
        } else if (ch == '.') {
            cinp();
            if (ch != '.')
                expect("'.'");
            cinp();
            tok = TOK_DOTS;
        } else {
            /* dots */
            tok = t;
        }
        return;
    } else if (t == '0') {
        if (ch == 'x' || ch == 'X') {
            q--;
            cinp();
            b = 16;
        } else if (tcc_ext && (ch == 'b' || ch == 'B')) {
            q--;
            cinp();
            b = 2;
        }
    }
    /* parse all digits. cannot check octal numbers at this stage
       because of floating point constants */
    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 >= b)
            break;
        if (q >= token_buf + STRING_MAX_SIZE) {
        num_too_long:
            error("number too long");
        }
        *q++ = ch;
        cinp();
    }
    if (ch == '.' ||
        ((ch == 'e' || ch == 'E') && b == 10) ||
        ((ch == 'p' || ch == 'P') && (b == 16 || b == 2))) {
        if (b != 10) {
            /* NOTE: strtox should support that for hexa numbers, but
               non ISOC99 libcs do not support it, so we prefer to do
               it by hand */
            /* hexadecimal or binary floats */
            /* XXX: handle overflows */
            *q = '\0';
            if (b == 16)
                shift = 4;
            else 
                shift = 2;
            bn_zero(bn);
            q = token_buf;
            while (1) {
                t = *q++;
                if (t == '\0') {
                    break;
                } else if (t >= 'a') {
                    t = t - 'a' + 10;
                } else if (t >= 'A') {
                    t = t - 'A' + 10;
                } else {
                    t = t - '0';
                }
                bn_lshift(bn, shift, t);
            }
            frac_bits = 0;
            if (ch == '.') {
                cinp();
                while (1) {
                    t = ch;
                    if (t >= 'a' && t <= 'f') {
                        t = t - 'a' + 10;
                    } else if (t >= 'A' && t <= 'F') {
                        t = t - 'A' + 10;
                    } else if (t >= '0' && t <= '9') {
                        t = t - '0';
                    } else {
                        break;
                    }
                    if (t >= b)
                        error("invalid digit");
                    bn_lshift(bn, shift, t);
                    frac_bits += shift;
                    cinp();
                }
            }
            if (ch != 'p' && ch != 'P')
                error("exponent expected");
            cinp();
            s = 1;
            exp_val = 0;
            if (ch == '+') {
                cinp();
            } else if (ch == '-') {
                s = -1;
                cinp();
            }
            if (ch < '0' || ch > '9')
                error("exponent digits expected");
            while (ch >= '0' && ch <= '9') {
                exp_val = exp_val * 10 + ch - '0';
                cinp();
            }
            exp_val = exp_val * s;
            
            /* now we can generate the number */
            /* XXX: should patch directly float number */
            d = (double)bn[1] * 4294967296.0 + (double)bn[0];
            d = ldexp(d, exp_val - frac_bits);
            t = toup(ch);
            if (t == 'F') {
                cinp();
                tok = TOK_CFLOAT;
                /* float : should handle overflow */
                tokc.f = (float)d;
            } else if (t == 'L') {
                cinp();
                tok = TOK_CLDOUBLE;
                /* XXX: not large enough */
                tokc.ld = (long double)d;
            } else {
                tok = TOK_CDOUBLE;
                tokc.d = d;
            }
        } else {
            /* decimal floats */
            if (ch == '.') {
                if (q >= token_buf + STRING_MAX_SIZE)
                    goto num_too_long;
                *q++ = ch;
                cinp();
            float_frac_parse:
                while (ch >= '0' && ch <= '9') {
                    if (q >= token_buf + STRING_MAX_SIZE)
                        goto num_too_long;
                    *q++ = ch;
                    cinp();
                }
            }
            if (ch == 'e' || ch == 'E') {
                if (q >= token_buf + STRING_MAX_SIZE)
                    goto num_too_long;
                *q++ = ch;
                cinp();
                if (ch == '-' || ch == '+') {
                    if (q >= token_buf + STRING_MAX_SIZE)
                        goto num_too_long;
                    *q++ = ch;
                    cinp();
                }
                if (ch < '0' || ch > '9')
                    error("exponent digits expected");
                while (ch >= '0' && ch <= '9') {
                    if (q >= token_buf + STRING_MAX_SIZE)
                        goto num_too_long;
                    *q++ = ch;
                    cinp();
                }
            }
            *q = '\0';
            t = toup(ch);
            errno = 0;
            if (t == 'F') {
                cinp();
                tok = TOK_CFLOAT;
                tokc.f = strtof(token_buf, NULL);
            } else if (t == 'L') {
                cinp();
                tok = TOK_CLDOUBLE;
                tokc.ld = strtold(token_buf, NULL);
            } else {
                tok = TOK_CDOUBLE;
                tokc.d = strtod(token_buf, NULL);
            }
        }
    } else {
        unsigned long long n, n1;
        int lcount;

        /* integer number */
        *q = '\0';
        q = token_buf;
        if (b == 10 && *q == '0') {
            b = 8;
            q++;
        }
        n = 0;
        while(1) {
            t = *q++;
            /* no need for checks except for base 10 / 8 errors */
            if (t == '\0') {
                break;
            } else if (t >= 'a') {
                t = t - 'a' + 10;
            } else if (t >= 'A') {
                t = t - 'A' + 10;
            } else {
                t = t - '0';
                if (t >= b)
                    error("invalid digit");
            }
            n1 = n;
            n = n * b + t;
            /* detect overflow */
            if (n < n1)
                error("integer constant overflow");
        }
        
        /* XXX: not exactly ANSI compliant */
        if ((n & 0xffffffff00000000LL) != 0) {
            if ((n >> 63) != 0)
                tok = TOK_CULLONG;
            else
                tok = TOK_CLLONG;
        } else if (n > 0x7fffffff) {
            tok = TOK_CUINT;
        } else {
            tok = TOK_CINT;
        }
        lcount = 0;
        for(;;) {
            t = toup(ch);
            if (t == 'L') {
                if (lcount >= 2)
                    error("three 'l' in integer constant");
                lcount++;
                if (lcount == 2) {
                    if (tok == TOK_CINT)
                        tok = TOK_CLLONG;
                    else if (tok == TOK_CUINT)
                        tok = TOK_CULLONG;
                }
                cinp();
            } else if (t == 'U') {
                if (tok == TOK_CINT)
                    tok = TOK_CUINT;
                else if (tok == TOK_CLLONG)
                    tok = TOK_CULLONG;
                cinp();
            } else {
                break;
            }
        }
        if (tok == TOK_CINT || tok == TOK_CUINT)
            tokc.ui = n;
        else
            tokc.ull = n;
    }
}


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

    /* skip spaces */
    while(1) {
        while (ch == '\n') {
            /* during preprocessor parsing, '\n' is a token */
            if (return_linefeed) {
                tok = TOK_LINEFEED;
                return;
            }
            cinp();
            while (ch == ' ' || ch == '\t')
                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') {
            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) || ch == '.') {
        parse_number();
    } else if (ch == '\'') {
        tok = TOK_CCHAR;
    char_const:
        minp();
        b = getq();
        /* this cast is needed if >= 128 */
        if (tok == TOK_CCHAR)
            b = (char)b; 
        tokc.i = b;
        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.ts = 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->\313..\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) {
    redo:
        tok = *macro_ptr;
        if (tok) {
            tok = tok_get(&macro_ptr, &tokc);
            if (tok == TOK_LINENUM) {
                file->line_num = tokc.i;
                goto redo;
            }
        }
    } 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, notfirst;
    Sym *s;
    TokenSym *ts;
    CValue cval;
    TokenString str;
    
    tok_str_new(&str);
    last_tok = 0;
    while(1) {
        t = tok_get(&macro_str, &cval);
        if (!t)
            break;
        if (t == '#') {
            /* stringize */
            t = tok_get(&macro_str, &cval);
            if (!t)
                break;
            s = sym_find2(args, t);
            if (s) {
                token_buf[0] = '\0';
                st = (int *)s->c;
                notfirst = 0;
                while (*st) {
                    if (notfirst)
                        pstrcat(token_buf, sizeof(token_buf), " ");
                    t = tok_get(&st, &cval);
                    pstrcat(token_buf, sizeof(token_buf), get_tok_str(t, &cval));
                    notfirst = 1;
                }
#ifdef PP_DEBUG
                printf("stringize: %s\n", token_buf);
#endif
                /* add string */
                ts = tok_alloc(token_buf, 0);
                cval.ts = ts;
                tok_str_add2(&str, TOK_STR, &cval);
            } else {
                tok_str_add2(&str, t, &cval);
            }
        } else if (t >= TOK_IDENT) {
            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) {
                    /* special case for var arg macros : ## eats the
                       ',' if empty VA_ARGS riable. */
                    /* XXX: test of the ',' is not 100%
                       reliable. should fix it to avoid security
                       problems */
                    if (gnu_ext && s->t && *st == 0 &&
                        last_tok == TOK_TWOSHARPS && 
                        str.len >= 2&& str.str[str.len - 2] == ',') {
                        /* suppress ',' '##' */
                        str.len -= 2;
                    } else {
                        while (*st)
                            tok_str_add(&str, *st++);
                    }
                } else {
                    macro_subst(&str, nested_list, st);
                }
            } else {
                tok_str_add(&str, t);
            }
        } else {
            tok_str_add2(&str, t, &cval);
        }
        last_tok = t;
    }
    tok_str_add(&str, 0);
    return str.str;
}

/* handle the '##' operator */
int *macro_twosharps(int *macro_str)
{
    TokenSym *ts;
    int *macro_ptr1;
    int t;
    char *p;
    CValue cval;
    TokenString macro_str1;
    
    tok_str_new(&macro_str1);
    tok = 0;
    while (1) {
        next_nomacro();
        if (tok == 0)
            break;
        while (*macro_ptr == TOK_TWOSHARPS) {
            macro_ptr++;
            macro_ptr1 = macro_ptr;
            t = *macro_ptr;
            if (t) {
                t = tok_get(&macro_ptr, &cval);
                /* XXX: we handle only most common cases: 
                   ident + ident or ident + number */
                if (tok >= TOK_IDENT && 
                    (t >= TOK_IDENT || t == TOK_CINT)) {
                    p = get_tok_str(tok, &tokc);
                    pstrcpy(token_buf, sizeof(token_buf), p);
                    p = get_tok_str(t, &cval);
                    pstrcat(token_buf, sizeof(token_buf), p);
                    ts = tok_alloc(token_buf, 0);
                    tok = ts->tok; /* modify current token */
                } else {
                    /* cannot merge tokens: skip '##' */
                    macro_ptr = macro_ptr1;
                    break;
                }
            }
        }
        tok_str_add2(&macro_str1, tok, &tokc);
    }
    tok_str_add(&macro_str1, 0);
    return macro_str1.str;
}

/* 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(TokenString *tok_str,
                 Sym **nested_list, int *macro_str)
{
    Sym *s, *args, *sa, *sa1;
    int parlevel, *mstr, t, *saved_macro_ptr;
    int mstr_allocated, *macro_str1;
    CValue cval;
    TokenString str;
    
    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__) {
            cval.i = file->line_num;
            tok_str_add2(tok_str, TOK_CINT, &cval);
        } else if (tok == TOK___FILE__) {
            cval.ts = tok_alloc(file->filename, 0);
            tok_str_add2(tok_str, TOK_STR, &cval);
        } else if (tok == TOK___DATE__) {
            cval.ts = tok_alloc("Jan  1 1970", 0);
            tok_str_add2(tok_str, TOK_STR, &cval);
        } else if (tok == TOK___TIME__) {
            cval.ts = tok_alloc("00:00:00", 0);
            tok_str_add2(tok_str, TOK_STR, &cval);
        } 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;
                /* NOTE: empty args are allowed, except if no args */
                for(;;) {
                    /* handle '()' case */
                    if (!args && tok == ')')
                        break;
                    if (!sa)
                        error("macro '%s' used with too many args",
                              get_tok_str(s->v, 0));
                    tok_str_new(&str);
                    parlevel = 0;
                    /* NOTE: non zero sa->t indicates VA_ARGS */
                    while ((parlevel > 0 || 
                            (tok != ')' && 
                             (tok != ',' || sa->t))) && 
                           tok != -1) {
                        if (tok == '(')
                            parlevel++;
                        else if (tok == ')')
                            parlevel--;
                        tok_str_add2(&str, tok, &tokc);
                        next_nomacro();
                    }
                    tok_str_add(&str, 0);
                    sym_push2(&args, sa->v & ~SYM_FIELD, sa->t, (int)str.str);
                    sa = sa->next;
                    if (tok == ')') {
                        /* special case for gcc var args: add an empty
                           var arg argument if it is omitted */
                        if (sa && sa->t && gnu_ext)
                            continue;
                        else
                            break;
                    }
                    if (tok != ',')
                        expect(",");
                    next_nomacro();
                }
                if (sa) {
                    error("macro '%s' used with too few args",
                          get_tok_str(s->v, 0));
                }

                /* 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, 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_str_add2(tok_str, 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(void)
{
    Sym *nested_list;
    TokenString str;

    /* special 'ungettok' case for label parsing */
    if (tok1) {
        tok = tok1;
        tokc = tok1c;
        tok1 = 0;
    } else {
    redo:
        if (!macro_ptr) {
            /* if not reading from macro substituted string, then try
               to substitute */
            /* XXX: optimize non macro case */
            tok_str_new(&str);
            nested_list = NULL;
            macro_subst(&str, &nested_list, NULL);
            if (str.str) {
                tok_str_add(&str, 0);
                macro_ptr = str.str;
                macro_ptr_allocated = str.str;
                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;
            }
        }
    }
#if defined(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 vsetc(int t, int r, CValue *vc)
{
    if (vtop >= vstack + VSTACK_SIZE)
        error("memory full");
    /* cannot let cpu flags if other instruction are generated */
    /* XXX: VT_JMP test too ? */
    if ((vtop->r & VT_VALMASK) == VT_CMP)
        gv(RC_INT);
    vtop++;
    vtop->t = t;
    vtop->r = r;
    vtop->r2 = VT_CONST;
    vtop->c = *vc;
}

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

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

    v = anon_sym++;
    sym = sym_push1(&global_stack, v, t | VT_STATIC, 0);
    sym->r = VT_CONST | VT_SYM;
    put_extern_sym(sym, sec, offset);
    return sym;
}

/* push a reference to a section offset by adding a dummy symbol */
/* XXX: add size */
void vpush_ref(int t, Section *sec, unsigned long offset)
{
    CValue cval;

    cval.sym = get_sym_ref(t, sec, offset, 0);
    vsetc(t, VT_CONST | VT_SYM, &cval);
}

/* push a reference to symbol v */
void vpush_sym(int t, int v)
{
    Sym *sym;
    CValue cval;

    sym = external_sym(v, t, 0);
    cval.sym = sym;
    vsetc(t, VT_CONST | VT_SYM, &cval);
}

void vset(int t, int r, int v)
{
    CValue cval;

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

void vswap(void)
{
    SValue tmp;

    tmp = vtop[0];
    vtop[0] = vtop[-1];
    vtop[-1] = tmp;
}

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

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

/* save r to the memory stack, and mark it as being free */
void save_reg(int r)
{
    int l, i, saved, t, size, align;
    SValue *p, sv;

    /* modify all stack values */
    saved = 0;
    l = 0;
    for(p=vstack;p<=vtop;p++) {
        i = p->r & VT_VALMASK;
        if ((p->r & VT_VALMASK) == r ||
            (p->r2 & VT_VALMASK) == r) {
            /* must save value on stack if not already done */
            if (!saved) {
                /* store register in the stack */
                t = p->t;
                if ((p->r & VT_LVAL) || 
                    (!is_float(t) && (t & VT_BTYPE) != VT_LLONG))
                    t = VT_INT;
                size = type_size(t, &align);
                loc = (loc - size) & -align;
                sv.t = t;
                sv.r = VT_LOCAL | VT_LVAL;
                sv.c.ul = loc;
                store(r, &sv);
#ifdef TCC_TARGET_I386
                /* x86 specific: need to pop fp register ST0 if saved */
                if (r == REG_ST0) {
                    o(0xd9dd); /* fstp %st(1) */
                }
#endif
                /* special long long case */
                if ((t & VT_BTYPE) == VT_LLONG) {
                    sv.c.ul += 4;
                    store(p->r2, &sv);
                }
                l = loc;
                saved = 1;
            }
            /* mark that stack entry as being saved on the stack */
            if (p->r & VT_LVAL)
                t = VT_LLOCAL;
            else
                t = VT_LOCAL;
            p->r = VT_LVAL | t;
            p->r2 = VT_CONST;
            p->c.ul = l;
        }
    }
}

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

    /* find a free register */
    for(r=0;r<NB_REGS;r++) {
        if (reg_classes[r] & rc) {
            for(p=vstack;p<=vtop;p++) {
                if ((p->r & VT_VALMASK) == r ||
                    (p->r2 & VT_VALMASK) == r)
                    goto notfound;
            }
            return r;
        }
    notfound: ;
    }
    
    /* no register left : free the first one on the stack (VERY
       IMPORTANT to start from the bottom to ensure that we don't
       spill registers used in gen_opi()) */
    for(p=vstack;p<=vtop;p++) {
        r = p->r & VT_VALMASK;
        if (r < VT_CONST && (reg_classes[r] & rc)) {
            save_reg(r);
            break;
        }
    }
    return r;
}

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

    if (r != s) {
        save_reg(r);
        sv.t = VT_INT;
        sv.r = s;
        sv.c.ul = 0;
        load(r, &sv);
    }
}

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

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

    vtop->r &= ~VT_MUSTBOUND;
    /* if lvalue, then use checking code before dereferencing */
    if (vtop->r & VT_LVAL) {
        /* if not VT_BOUNDED value, then make one */
        if (!(vtop->r & VT_BOUNDED)) {
            lval_type = vtop->r & (VT_LVAL_TYPE | VT_LVAL);
            gaddrof();
            vpushi(0);
            gen_bounded_ptr_add();
            vtop->r |= lval_type;
        }
        /* then check for dereferencing */
        gen_bounded_ptr_deref();
    }
}
#endif

/* store vtop a register belonging to class 'rc'. lvalues are
   converted to values. Cannot be used if cannot be converted to
   register value (such as structures). */
int gv(int rc)
{
    int r, r2, rc2, bit_pos, bit_size, size, align, i;
    unsigned long long ll;

    /* NOTE: get_reg can modify vstack[] */
    if (vtop->t & VT_BITFIELD) {
        bit_pos = (vtop->t >> VT_STRUCT_SHIFT) & 0x3f;
        bit_size = (vtop->t >> (VT_STRUCT_SHIFT + 6)) & 0x3f;
        /* remove bit field info to avoid loops */
        vtop->t &= ~(VT_BITFIELD | (-1 << VT_STRUCT_SHIFT));
        /* generate shifts */
        vpushi(32 - (bit_pos + bit_size));
        gen_op(TOK_SHL);
        vpushi(32 - bit_size);
        /* NOTE: transformed to SHR if unsigned */
        gen_op(TOK_SAR);
        r = gv(rc);
    } else {
        if (is_float(vtop->t) && 
            (vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) {
            int v;
            Sym *sym;
            int *ptr;

            /* XXX: unify with initializers handling ? */
            /* CPUs usually cannot use float constants, so we store them
               generically in data segment */
            size = type_size(vtop->t, &align);
            data_section->data_offset = (data_section->data_offset + 
                                         align - 1) & -align;
            /* XXX: not portable yet */
            ptr = section_ptr(data_section, size);
            size = size >> 2;
            for(i=0;i<size;i++)
                ptr[i] = vtop->c.tab[i];

            v = anon_sym++;
            sym = sym_push1(&global_stack, v, vtop->t | VT_STATIC, 0);
            sym->r = VT_CONST | VT_SYM;
            put_extern_sym(sym, data_section, data_section->data_offset);

            vtop->r |= VT_LVAL | VT_SYM;
            vtop->c.sym = sym;
            data_section->data_offset += size << 2;
        }
#ifdef CONFIG_TCC_BCHECK
        if (vtop->r & VT_MUSTBOUND) 
            gbound();
#endif

        r = vtop->r & VT_VALMASK;
        /* need to reload if:
           - constant
           - lvalue (need to dereference pointer)
           - already a register, but not in the right class */
        if (r >= VT_CONST || 
            (vtop->r & VT_LVAL) ||
            !(reg_classes[r] & rc) ||
            ((vtop->t & VT_BTYPE) == VT_LLONG && 
             !(reg_classes[vtop->r2] & rc))) {
            r = get_reg(rc);
            if ((vtop->t & VT_BTYPE) == VT_LLONG) {
                /* two register type load : expand to two words
                   temporarily */
                if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) {
                    /* load constant */
                    ll = vtop->c.ull;
                    vtop->c.ui = ll; /* first word */
                    load(r, vtop);
                    vtop->r = r; /* save register value */
                    vpushi(ll >> 32); /* second word */
                } else if (r >= VT_CONST || 
                           (vtop->r & VT_LVAL)) {
                    /* load from memory */
                    load(r, vtop);
                    vdup();
                    vtop[-1].r = r; /* save register value */
                    /* increment pointer to get second word */
                    vtop->t = VT_INT;
                    gaddrof();
                    vpushi(4);
                    gen_op('+');
                    vtop->r |= VT_LVAL;
                } else {
                    /* move registers */
                    load(r, vtop);
                    vdup();
                    vtop[-1].r = r; /* save register value */
                    vtop->r = vtop[-1].r2;
                }
                /* allocate second register */
                rc2 = RC_INT;
                if (rc == RC_IRET)
                    rc2 = RC_LRET;
                r2 = get_reg(rc2);
                load(r2, vtop);
                vpop();
                /* write second register */
                vtop->r2 = r2;
            } else if ((vtop->r & VT_LVAL) && !is_float(vtop->t)) {
                int t1, t;
                /* lvalue of scalar type : need to use lvalue type
                   because of possible cast */
                t = vtop->t;
                t1 = t;
                /* compute memory access type */
                if (vtop->r & VT_LVAL_BYTE)
                    t = VT_BYTE;
                else if (vtop->r & VT_LVAL_SHORT)
                    t = VT_SHORT;
                if (vtop->r & VT_LVAL_UNSIGNED)
                    t |= VT_UNSIGNED;
                vtop->t = t;
                load(r, vtop);
                /* restore wanted type */
                vtop->t = t1;
            } else {
                /* one register type load */
                load(r, vtop);
            }
        }
        vtop->r = r;
    }
    return r;
}

/* generate vtop[-1] and vtop[0] in resp. classes rc1 and rc2 */
void gv2(int rc1, int rc2)
{
    /* generate more generic register first */
    if (rc1 <= rc2) {
        vswap();
        gv(rc1);
        vswap();
        gv(rc2);
        /* test if reload is needed for first register */
        if ((vtop[-1].r & VT_VALMASK) >= VT_CONST) {
            vswap();
            gv(rc1);
            vswap();
        }
    } else {
        gv(rc2);
        vswap();
        gv(rc1);
        vswap();
        /* test if reload is needed for first register */
        if ((vtop[0].r & VT_VALMASK) >= VT_CONST) {
            gv(rc2);
        }
    }
}

/* expand long long on stack in two int registers */
void lexpand(void)
{
    int u;

    u = vtop->t & VT_UNSIGNED;
    gv(RC_INT);
    vdup();
    vtop[0].r = vtop[-1].r2;
    vtop[0].r2 = VT_CONST;
    vtop[-1].r2 = VT_CONST;
    vtop[0].t = VT_INT | u;
    vtop[-1].t = VT_INT | u;
}

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

/* rotate n first stack elements to the bottom */
void vrotb(int n)
{
    int i;
    SValue tmp;

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

/* pop stack value */
void vpop(void)
{
    int v;
    v = vtop->r & VT_VALMASK;
#ifdef TCC_TARGET_I386
    /* for x86, we need to pop the FP stack */
    if (v == REG_ST0) {
        o(0xd9dd); /* fstp %st(1) */
    } else
#endif
    if (v == VT_JMP || v == VT_JMPI) {
        /* need to put correct jump if && or || without test */
        gsym(vtop->c.ul);
    }
    vtop--;
}

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

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

/* generate CPU independent (unsigned) long long operations */
void gen_opl(int op)
{
    int t, a, b, op1, c, i;
    int func;
    GFuncContext gf;
    SValue tmp;

    switch(op) {
    case '/':
    case TOK_PDIV:
        func = TOK___divdi3;
        goto gen_func;
    case TOK_UDIV:
        func = TOK___udivdi3;
        goto gen_func;
    case '%':
        func = TOK___moddi3;
        goto gen_func;
    case TOK_UMOD:
        func = TOK___umoddi3;
    gen_func:
        /* call generic long long function */
        gfunc_start(&gf, FUNC_CDECL);
        gfunc_param(&gf);
        gfunc_param(&gf);
        vpush_sym(func_old_type, func);
        gfunc_call(&gf);
        vpushi(0);
        vtop->r = REG_IRET;
        vtop->r2 = REG_LRET;
        break;
    case '^':
    case '&':
    case '|':
    case '*':
    case '+':
    case '-':
        t = vtop->t;
        vswap();
        lexpand();
        vrotb(3);
        lexpand();
        /* stack: L1 H1 L2 H2 */
        tmp = vtop[0];
        vtop[0] = vtop[-3];
        vtop[-3] = tmp;
        tmp = vtop[-2];
        vtop[-2] = vtop[-3];
        vtop[-3] = tmp;
        vswap();
        /* stack: H1 H2 L1 L2 */
        if (op == '*') {
            vpushv(vtop - 1);
            vpushv(vtop - 1);
            gen_op(TOK_UMULL);
            lexpand();
            /* stack: H1 H2 L1 L2 ML MH */
            for(i=0;i<4;i++)
                vrotb(6);
            /* stack: ML MH H1 H2 L1 L2 */
            tmp = vtop[0];
            vtop[0] = vtop[-2];
            vtop[-2] = tmp;
            /* stack: ML MH H1 L2 H2 L1 */
            gen_op('*');
            vrotb(3);
            vrotb(3);
            gen_op('*');
            /* stack: ML MH M1 M2 */
            gen_op('+');
            gen_op('+');
        } else if (op == '+' || op == '-') {
            /* XXX: add non carry method too (for MIPS or alpha) */
            if (op == '+')
                op1 = TOK_ADDC1;
            else
                op1 = TOK_SUBC1;
            gen_op(op1);
            /* stack: H1 H2 (L1 op L2) */
            vrotb(3);
            vrotb(3);
            gen_op(op1 + 1); /* TOK_xxxC2 */
        } else {
            gen_op(op);
            /* stack: H1 H2 (L1 op L2) */
            vrotb(3);
            vrotb(3);
            /* stack: (L1 op L2) H1 H2 */
            gen_op(op);
            /* stack: (L1 op L2) (H1 op H2) */
        }
        /* stack: L H */
        lbuild(t);
        break;
    case TOK_SAR:
    case TOK_SHR:
    case TOK_SHL:
        if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
            t = vtop[-1].t;
            vswap();
            lexpand();
            vrotb(3);
        /* stack: L H shift */
            c = (int)vtop->c.i;
            /* constant: simpler */
            /* NOTE: all comments are for SHL. the other cases are
               done by swaping words */
            vpop();
            if (op != TOK_SHL)
                vswap();
            if (c >= 32) {
                /* stack: L H */
                vpop();
                if (c > 32) {
                    vpushi(c - 32);
                    gen_op(op);
                }
                if (op != TOK_SAR) {
                    vpushi(0);
                } else {
                    gv_dup();
                    vpushi(31);
                    gen_op(TOK_SAR);
                }
                vswap();
            } else {
                vswap();
                gv_dup();
                /* stack: H L L */
                vpushi(c);
                gen_op(op);
                vswap();
                vpushi(32 - c);
                if (op == TOK_SHL)
                    gen_op(TOK_SHR);
                else
                    gen_op(TOK_SHL);
                vrotb(3);
                /* stack: L L H */
                vpushi(c);
                gen_op(op);
                gen_op('|');
            }
            if (op != TOK_SHL)
                vswap();
            lbuild(t);
        } else {
            /* XXX: should provide a faster fallback on x86 ? */
            switch(op) {
            case TOK_SAR:
                func = TOK___sardi3;
                goto gen_func;
            case TOK_SHR:
                func = TOK___shrdi3;
                goto gen_func;
            case TOK_SHL:
                func = TOK___shldi3;
                goto gen_func;
            }
        }
        break;
    default:
        /* compare operations */
        t = vtop->t;
        vswap();
        lexpand();
        vrotb(3);
        lexpand();
        /* stack: L1 H1 L2 H2 */
        tmp = vtop[-1];
        vtop[-1] = vtop[-2];
        vtop[-2] = tmp;
        /* stack: L1 L2 H1 H2 */
        /* compare high */
        op1 = op;
        /* when values are equal, we need to compare low words. since
           the jump is inverted, we invert the test too. */
        if (op1 == TOK_LT)
            op1 = TOK_LE;
        else if (op1 == TOK_GT)
            op1 = TOK_GE;
        else if (op1 == TOK_ULT)
            op1 = TOK_ULE;
        else if (op1 == TOK_UGT)
            op1 = TOK_UGE;
        a = 0;
        b = 0;
        gen_op(op1);
        if (op1 != TOK_NE) {
            a = gtst(1, 0);
        }
        if (op != TOK_EQ) {
            /* generate non equal test */
            /* XXX: NOT PORTABLE yet */
            if (a == 0) {
                b = gtst(0, 0);
            } else {
#ifdef TCC_TARGET_I386
                b = psym(0x850f, 0);
#else
                error("not implemented");
#endif
            }
        }
        /* compare low */
        gen_op(op);
        a = gtst(1, a);
        gsym(b);
        vset(VT_INT, VT_JMPI, a);
        break;
    }
}

/* handle integer constant optimizations and various machine
   independant opt */
void gen_opic(int op)
{
    int fc, c1, c2, n;
    SValue *v1, *v2;

    v1 = vtop - 1;
    v2 = vtop;
    /* currently, we cannot do computations with forward symbols */
    c1 = (v1->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    c2 = (v2->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
    if (c1 && c2) {
        fc = v2->c.i;
        switch(op) {
        case '+': v1->c.i += fc; break;
        case '-': v1->c.i -= fc; break;
        case '&': v1->c.i &= fc; break;
        case '^': v1->c.i ^= fc; break;
        case '|': v1->c.i |= fc; break;
        case '*': v1->c.i *= fc; break;

        case TOK_PDIV:
        case '/':
        case '%':
        case TOK_UDIV:
        case TOK_UMOD:
            /* if division by zero, generate explicit division */
            if (fc == 0) {
                if (const_wanted)
                    error("division by zero in constant");
                goto general_case;
            }
            switch(op) {
            default: v1->c.i /= fc; break;
            case '%': v1->c.i %= fc; break;
            case TOK_UDIV: v1->c.i = (unsigned)v1->c.i / fc; break;
            case TOK_UMOD: v1->c.i = (unsigned)v1->c.i % fc; break;
            }
            break;
        case TOK_SHL: v1->c.i <<= fc; break;
        case TOK_SHR: v1->c.i = (unsigned)v1->c.i >> fc; break;
        case TOK_SAR: v1->c.i >>= fc; break;
            /* tests */
        case TOK_ULT: v1->c.i = (unsigned)v1->c.i < (unsigned)fc; break;
        case TOK_UGE: v1->c.i = (unsigned)v1->c.i >= (unsigned)fc; break;
        case TOK_EQ: v1->c.i = v1->c.i == fc; break;
        case TOK_NE: v1->c.i = v1->c.i != fc; break;
        case TOK_ULE: v1->c.i = (unsigned)v1->c.i <= (unsigned)fc; break;
        case TOK_UGT: v1->c.i = (unsigned)v1->c.i > (unsigned)fc; break;
        case TOK_LT: v1->c.i = v1->c.i < fc; break;
        case TOK_GE: v1->c.i = v1->c.i >= fc; break;
        case TOK_LE: v1->c.i = v1->c.i <= fc; break;
        case TOK_GT: v1->c.i = v1->c.i > fc; break;
            /* logical */
        case TOK_LAND: v1->c.i = v1->c.i && fc; break;
        case TOK_LOR: v1->c.i = v1->c.i || fc; break;
        default:
            goto general_case;
        }
        vtop--;
    } else {
        /* if commutative ops, put c2 as constant */
        if (c1 && (op == '+' || op == '&' || op == '^' || 
                   op == '|' || op == '*')) {
            vswap();
            swap(&c1, &c2);
        }
        fc = vtop->c.i;
        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))) {
            /* nothing to do */
            vtop--;
        } 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++;
                }
                vtop->c.i = n;
                if (op == '*')
                    op = TOK_SHL;
                else if (op == TOK_PDIV)
                    op = TOK_SAR;
                else
                    op = TOK_SHR;
            }
            goto general_case;
        } else {
        general_case:
            /* call low level op generator */
            gen_opi(op);
        }
    }
}

/* generate a floating point operation with constant propagation */
void gen_opif(int op)
{
    int c1, c2;
    SValue *v1, *v2;
    long double f1, f2;

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

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

        switch(op) {
        case '+': f1 += f2; break;
        case '-': f1 -= f2; break;
        case '*': f1 *= f2; break;
        case '/': 
            if (f2 == 0.0) {
                if (const_wanted)
                    error("division by zero in constant");
                goto general_case;
            }
            f1 /= f2; 
            break;
            /* XXX: also handles tests ? */
        default:
            goto general_case;
        }
        /* XXX: overflow test ? */
        if (v1->t == VT_FLOAT) {
            v1->c.f = f1;
        } else if (v1->t == VT_DOUBLE) {
            v1->c.d = f1;
        } else {
            v1->c.ld = f1;
        }
        vtop--;
    } else {
    general_case:
        gen_opf(op);
    }
}


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

#if 0
void check_pointer_types(SValue *p1, SValue *p2)
{
    char buf1[256], buf2[256];
    int t1, t2;
    t1 = p1->t;
    t2 = p2->t;
    if (!is_compatible_types(t1, t2)) {
        type_to_str(buf1, sizeof(buf1), t1, NULL);
        type_to_str(buf2, sizeof(buf2), t2, NULL);
        error("incompatible pointers '%s' and '%s'", buf1, buf2);
    }
}
#endif

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

    t1 = vtop[-1].t;
    t2 = vtop[0].t;
    bt1 = t1 & VT_BTYPE;
    bt2 = t2 & VT_BTYPE;
        
    if (bt1 == VT_PTR || bt2 == VT_PTR) {
        /* at least one operand is a pointer */
        /* relationnal op: must be both pointers */
        if (op >= TOK_ULT && op <= TOK_GT) {
            //            check_pointer_types(vtop, vtop - 1);
            /* pointers are handled are unsigned */
            t = VT_INT | VT_UNSIGNED;
            goto std_op;
        }
        /* if both pointers, then it must be the '-' op */
        if ((t1 & VT_BTYPE) == VT_PTR && 
            (t2 & VT_BTYPE) == VT_PTR) {
            if (op != '-')
                error("cannot use pointers here");
            //            check_pointer_types(vtop - 1, vtop);
            /* XXX: check that types are compatible */
            u = pointed_size(t1);
            gen_opic(op);
            /* set to integer type */
            vtop->t = VT_INT; 
            vpushi(u);
            gen_op(TOK_PDIV);
        } else {
            /* exactly one pointer : must be '+' or '-'. */
            if (op != '-' && op != '+')
                error("cannot use pointers here");
            /* Put pointer as first operand */
            if ((t2 & VT_BTYPE) == VT_PTR) {
                vswap();
                swap(&t1, &t2);
            }
            /* XXX: cast to int ? (long long case) */
            vpushi(pointed_size(vtop[-1].t));
            gen_op('*');
#ifdef CONFIG_TCC_BCHECK
            /* if evaluating constant expression, no code should be
               generated, so no bound check */
            if (do_bounds_check && !const_wanted) {
                /* if bounded pointers, we generate a special code to
                   test bounds */
                if (op == '-') {
                    vpushi(0);
                    vswap();
                    gen_op('-');
                }
                gen_bounded_ptr_add();
            } else
#endif
            {
                gen_opic(op);
            }
            /* put again type if gen_opic() swaped operands */
            vtop->t = t1;
        }
    } else if (is_float(bt1) || is_float(bt2)) {
        /* compute bigger type and do implicit casts */
        if (bt1 == VT_LDOUBLE || bt2 == VT_LDOUBLE) {
            t = VT_LDOUBLE;
        } else if (bt1 == VT_DOUBLE || bt2 == VT_DOUBLE) {
            t = VT_DOUBLE;
        } else {
            t = VT_FLOAT;
        }
        /* floats can only be used for a few operations */
        if (op != '+' && op != '-' && op != '*' && op != '/' &&
            (op < TOK_ULT || op > TOK_GT))
            error("invalid operands for binary operation");
        goto std_op;
    } else if (bt1 == VT_LLONG || bt2 == VT_LLONG) {
        /* cast to biggest op */
        t = VT_LLONG;
        /* convert to unsigned if it does not fit in a long long */
        if ((t1 & (VT_BTYPE | VT_UNSIGNED)) == (VT_LLONG | VT_UNSIGNED) ||
            (t2 & (VT_BTYPE | VT_UNSIGNED)) == (VT_LLONG | VT_UNSIGNED))
            t |= VT_UNSIGNED;
        goto std_op;
    } else {
        /* integer operations */
        t = VT_INT;
        /* convert to unsigned if it does not fit in an integer */
        if ((t1 & (VT_BTYPE | VT_UNSIGNED)) == (VT_INT | VT_UNSIGNED) ||
            (t2 & (VT_BTYPE | VT_UNSIGNED)) == (VT_INT | VT_UNSIGNED))
            t |= VT_UNSIGNED;
    std_op:
        /* XXX: currently, some unsigned operations are explicit, so
           we modify them here */
        if (t & VT_UNSIGNED) {
            if (op == TOK_SAR)
                op = TOK_SHR;
            else if (op == '/')
                op = TOK_UDIV;
            else if (op == '%')
                op = TOK_UMOD;
            else if (op == TOK_LT)
                op = TOK_ULT;
            else if (op == TOK_GT)
                op = TOK_UGT;
            else if (op == TOK_LE)
                op = TOK_ULE;
            else if (op == TOK_GE)
                op = TOK_UGE;
        }
        vswap();
        gen_cast(t);
        vswap();
        /* special case for shifts and long long: we keep the shift as
           an integer */
        if (op == TOK_SHR || op == TOK_SAR || op == TOK_SHL)
            gen_cast(VT_INT);
        else
            gen_cast(t);
        if (is_float(t))
            gen_opif(op);
        else if ((t & VT_BTYPE) == VT_LLONG)
            gen_opl(op);
        else
            gen_opic(op);
        if (op >= TOK_ULT && op <= TOK_GT) {
            /* relationnal op: the result is an int */
            vtop->t = VT_INT;
        } else {
            vtop->t = t;
        }
    }
}

/* generic itof for unsigned long long case */
void gen_cvt_itof1(int t)
{
    GFuncContext gf;

    if ((vtop->t & (VT_BTYPE | VT_UNSIGNED)) == 
        (VT_LLONG | VT_UNSIGNED)) {

        gfunc_start(&gf, FUNC_CDECL);
        gfunc_param(&gf);
        if (t == VT_FLOAT)
            vpush_sym(func_old_type, TOK___ulltof);
        else if (t == VT_DOUBLE)
            vpush_sym(func_old_type, TOK___ulltod);
        else
            vpush_sym(func_old_type, TOK___ulltold);
        gfunc_call(&gf);
        vpushi(0);
        vtop->r = REG_FRET;
    } else {
        gen_cvt_itof(t);
    }
}

/* generic ftoi for unsigned long long case */
void gen_cvt_ftoi1(int t)
{
    GFuncContext gf;
    int st;

    if (t == (VT_LLONG | VT_UNSIGNED)) {
        /* not handled natively */
        gfunc_start(&gf, FUNC_CDECL);
        st = vtop->t & VT_BTYPE;
        gfunc_param(&gf);
        if (st == VT_FLOAT)
            vpush_sym(func_old_type, TOK___fixunssfdi);
        else if (st == VT_DOUBLE)
            vpush_sym(func_old_type, TOK___fixunsdfdi);
        else
            vpush_sym(func_old_type, TOK___fixunsxfdi);
        gfunc_call(&gf);
        vpushi(0);
        vtop->r = REG_IRET;
        vtop->r2 = REG_LRET;
    } else {
        gen_cvt_ftoi(t);
    }
}

/* force char or short cast */
void force_charshort_cast(int t)
{
    int bits, dbt;
    dbt = t & VT_BTYPE;
    /* XXX: add optimization if lvalue : just change type and offset */
    if (dbt == VT_BYTE)
        bits = 8;
    else
        bits = 16;
    if (t & VT_UNSIGNED) {
        vpushi((1 << bits) - 1);
        gen_op('&');
    } else {
        bits = 32 - bits;
        vpushi(bits);
        gen_op(TOK_SHL);
        vpushi(bits);
        gen_op(TOK_SAR);
    }
}

/* cast 'vtop' to 't' type */
void gen_cast(int t)
{
    int sbt, dbt, sf, df, c;

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

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

    if (sbt != dbt) {
        sf = is_float(sbt);
        df = is_float(dbt);
        c = (vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
        if (sf && df) {
            /* convert from fp to fp */
            if (c) {
                /* constant case: we can do it now */
                /* XXX: in ISOC, cannot do it if error in convert */
                if (dbt == VT_FLOAT && sbt == VT_DOUBLE) 
                    vtop->c.f = (float)vtop->c.d;
                else if (dbt == VT_FLOAT && sbt == VT_LDOUBLE) 
                    vtop->c.f = (float)vtop->c.ld;
                else if (dbt == VT_DOUBLE && sbt == VT_FLOAT) 
                    vtop->c.d = (double)vtop->c.f;
                else if (dbt == VT_DOUBLE && sbt == VT_LDOUBLE) 
                    vtop->c.d = (double)vtop->c.ld;
                else if (dbt == VT_LDOUBLE && sbt == VT_FLOAT) 
                    vtop->c.ld = (long double)vtop->c.f;
                else if (dbt == VT_LDOUBLE && sbt == VT_DOUBLE) 
                    vtop->c.ld = (long double)vtop->c.d;
            } else {
                /* non constant case: generate code */
                gen_cvt_ftof(dbt);
            }
        } else if (df) {
            /* convert int to fp */
            if (c) {
                switch(sbt) {
                case VT_LLONG | VT_UNSIGNED:
                case VT_LLONG:
                    /* XXX: add const cases for long long */
                    goto do_itof;
                case VT_INT | VT_UNSIGNED:
                    switch(dbt) {
                    case VT_FLOAT: vtop->c.f = (float)vtop->c.ui; break;
                    case VT_DOUBLE: vtop->c.d = (double)vtop->c.ui; break;
                    case VT_LDOUBLE: vtop->c.ld = (long double)vtop->c.ui; break;
                    }
                    break;
                default:
                    switch(dbt) {
                    case VT_FLOAT: vtop->c.f = (float)vtop->c.i; break;
                    case VT_DOUBLE: vtop->c.d = (double)vtop->c.i; break;
                    case VT_LDOUBLE: vtop->c.ld = (long double)vtop->c.i; break;
                    }
                    break;
                }
            } else {
            do_itof:
                gen_cvt_itof1(dbt);
            }
        } else if (sf) {
            /* convert fp to int */
            /* we handle char/short/etc... with generic code */
            if (dbt != (VT_INT | VT_UNSIGNED) &&
                dbt != (VT_LLONG | VT_UNSIGNED) &&
                dbt != VT_LLONG)
                dbt = VT_INT;
            if (c) {
                switch(dbt) {
                case VT_LLONG | VT_UNSIGNED:
                case VT_LLONG:
                    /* XXX: add const cases for long long */
                    goto do_ftoi;
                case VT_INT | VT_UNSIGNED:
                    switch(sbt) {
                    case VT_FLOAT: vtop->c.ui = (unsigned int)vtop->c.d; break;
                    case VT_DOUBLE: vtop->c.ui = (unsigned int)vtop->c.d; break;
                    case VT_LDOUBLE: vtop->c.ui = (unsigned int)vtop->c.d; break;
                    }
                    break;
                default:
                    /* int case */
                    switch(sbt) {
                    case VT_FLOAT: vtop->c.i = (int)vtop->c.d; break;
                    case VT_DOUBLE: vtop->c.i = (int)vtop->c.d; break;
                    case VT_LDOUBLE: vtop->c.i = (int)vtop->c.d; break;
                    }
                    break;
                }
            } else {
            do_ftoi:
                gen_cvt_ftoi1(dbt);
            }
            if (dbt == VT_INT && (t & (VT_BTYPE | VT_UNSIGNED)) != dbt) {
                /* additionnal cast for char/short/bool... */
                vtop->t = dbt;
                gen_cast(t);
            }
        } else if ((dbt & VT_BTYPE) == VT_LLONG) {
            if ((sbt & VT_BTYPE) != VT_LLONG) {
                /* scalar to long long */
                if (c) {
                    if (sbt == (VT_INT | VT_UNSIGNED))
                        vtop->c.ll = vtop->c.ui;
                    else
                        vtop->c.ll = vtop->c.i;
                } else {
                    /* machine independant conversion */
                    gv(RC_INT);
                    /* generate high word */
                    if (sbt == (VT_INT | VT_UNSIGNED)) {
                        vpushi(0);
                        gv(RC_INT);
                    } else {
                        gv_dup();
                        vpushi(31);
                        gen_op(TOK_SAR);
                    }
                    /* patch second register */
                    vtop[-1].r2 = vtop->r;
                    vpop();
                }
            }
        } else if (dbt == VT_BOOL) {
            /* scalar to bool */
            vpushi(0);
            gen_op(TOK_NE);
        } else if ((dbt & VT_BTYPE) == VT_BYTE || 
                   (dbt & VT_BTYPE) == VT_SHORT) {
            force_charshort_cast(t);
        } else if ((dbt & VT_BTYPE) == VT_INT) {
            /* scalar to int */
            if (sbt == VT_LLONG) {
                /* from long long: just take low order word */
                lexpand();
                vpop();
            } 
            /* if lvalue and single word type, nothing to do because
               the lvalue already contains the real type size (see
               VT_LVAL_xxx constants) */
        }
    }
    vtop->t = t;
}

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

    bt = t & VT_BTYPE;
    if (bt == 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 (bt == VT_PTR) {
        if (t & VT_ARRAY) {
            s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT));
            return type_size(s->t, a) * s->c;
        } else {
            *a = PTR_SIZE;
            return PTR_SIZE;
        }
    } else if (bt == VT_LDOUBLE) {
        *a = LDOUBLE_ALIGN;
        return LDOUBLE_SIZE;
    } else if (bt == VT_DOUBLE || bt == VT_LLONG) {
        *a = 8;
        return 8;
    } else if (bt == VT_INT || bt == VT_ENUM || bt == VT_FLOAT) {
        *a = 4;
        return 4;
    } else if (bt == VT_SHORT) {
        *a = 2;
        return 2;
    } else {
        /* char, void, function, _Bool */
        *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_TYPE);
}

int mk_pointer(int t)
{
    int p;
    p = anon_sym++;
    sym_push(p, t, 0, -1);
    return VT_PTR | (p << VT_STRUCT_SHIFT) | (t & ~VT_TYPE);
}

int is_compatible_types(int t1, int t2)
{
    Sym *s1, *s2;
    int bt1, bt2;

    t1 &= VT_TYPE;
    t2 &= VT_TYPE;
    bt1 = t1 & VT_BTYPE;
    bt2 = t2 & VT_BTYPE;
    if (bt1 == VT_PTR) {
        t1 = pointed_type(t1);
        /* if function, then convert implicitely to function pointer */
        if (bt2 != VT_FUNC) {
            if (bt2 != 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 (bt1 == VT_STRUCT || bt2 == VT_STRUCT) {
        return (t2 == t1);
    } else if (bt1 == VT_FUNC) {
        if (bt2 != 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;
    }
}

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

    t = t & VT_TYPE;
    bt = t & VT_BTYPE;
    buf[0] = '\0';
    if (t & VT_UNSIGNED)
        pstrcat(buf, buf_size, "unsigned ");
    switch(bt) {
    case VT_VOID:
        tstr = "void";
        goto add_tstr;
    case VT_BOOL:
        tstr = "_Bool";
        goto add_tstr;
    case VT_BYTE:
        tstr = "char";
        goto add_tstr;
    case VT_SHORT:
        tstr = "short";
        goto add_tstr;
    case VT_INT:
        tstr = "int";
        goto add_tstr;
    case VT_LONG:
        tstr = "long";
        goto add_tstr;
    case VT_LLONG:
        tstr = "long long";
        goto add_tstr;
    case VT_FLOAT:
        tstr = "float";
        goto add_tstr;
    case VT_DOUBLE:
        tstr = "double";
        goto add_tstr;
    case VT_LDOUBLE:
        tstr = "long double";
    add_tstr:
        pstrcat(buf, buf_size, tstr);
        break;
    case VT_ENUM:
    case VT_STRUCT:
        if (bt == VT_STRUCT)
            tstr = "struct ";
        else
            tstr = "enum ";
        pstrcat(buf, buf_size, tstr);
        v = (unsigned)t >> VT_STRUCT_SHIFT;
        if (v >= SYM_FIRST_ANOM)
            pstrcat(buf, buf_size, "<anonymous>");
        else
            pstrcat(buf, buf_size, get_tok_str(v, NULL));
        break;
    case VT_FUNC:
        s = sym_find((unsigned)t >> VT_STRUCT_SHIFT);
        type_to_str(buf, buf_size, s->t, varstr);
        pstrcat(buf, buf_size, "(");
        sa = s->next;
        while (sa != NULL) {
            type_to_str(buf1, sizeof(buf1), sa->t, NULL);
            pstrcat(buf, buf_size, buf1);
            sa = sa->next;
            if (sa)
                pstrcat(buf, buf_size, ", ");
        }
        pstrcat(buf, buf_size, ")");
        goto no_var;
    case VT_PTR:
        s = sym_find((unsigned)t >> VT_STRUCT_SHIFT);
        pstrcpy(buf1, sizeof(buf1), "*");
        if (varstr)
            pstrcat(buf1, sizeof(buf1), varstr);
        type_to_str(buf, buf_size, s->t, buf1);
        goto no_var;
    }
    if (varstr) {
        pstrcat(buf, buf_size, " ");
        pstrcat(buf, buf_size, varstr);
    }
 no_var: ;
}

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

    st = vtop->t; /* source type */
    if ((dt & VT_BTYPE) == VT_PTR) {
        /* special cases for pointers */
        /* a function is implicitely a function pointer */
        if ((st & VT_BTYPE) == VT_FUNC) {
            if (!is_compatible_types(pointed_type(dt), st))
                goto error;
            else
                goto type_ok;
        }
        /* '0' can also be a pointer */
        if ((st & VT_BTYPE) == VT_INT &&
            ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) &&
            vtop->c.i == 0)
            goto type_ok;
    }
    if (!is_compatible_types(dt, st)) {
    error:
        type_to_str(buf1, sizeof(buf1), st, NULL);
        type_to_str(buf2, sizeof(buf2), dt, NULL);
        error("cannot cast '%s' to '%s'", buf1, buf2);
    }
 type_ok:
    gen_cast(dt);
}

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

    ft = vtop[-1].t;
    sbt = vtop->t & VT_BTYPE;
    dbt = ft & VT_BTYPE;
    if (((sbt == VT_INT || sbt == VT_SHORT) && dbt == VT_BYTE) ||
        (sbt == VT_INT && dbt == VT_SHORT)) {
        /* optimize char/short casts */
        delayed_cast = VT_MUSTCAST;
        vtop->t = ft & VT_TYPE;
    } else {
        delayed_cast = 0;
        gen_assign_cast(ft & VT_TYPE);
    }

    if (sbt == VT_STRUCT) {
        /* if structure, only generate pointer */
        /* structure assignment : generate memcpy */
        /* XXX: optimize if small size */
        vdup();
        gfunc_start(&gf, FUNC_CDECL);
        /* type size */
        size = type_size(vtop->t, &align);
        vpushi(size);
        gfunc_param(&gf);
        /* source */
        vtop->t = VT_INT;
        gaddrof();
        gfunc_param(&gf);
        /* destination */
        vswap();
        vtop->t = VT_INT;
        gaddrof();
        gfunc_param(&gf);

        save_regs(0);
        vpush_sym(func_old_type, TOK_memcpy);
        gfunc_call(&gf);
        /* leave source on stack */
    } else if (ft & VT_BITFIELD) {
        /* bitfield store handling */
        bit_pos = (ft >> VT_STRUCT_SHIFT) & 0x3f;
        bit_size = (ft >> (VT_STRUCT_SHIFT + 6)) & 0x3f;
        /* remove bit field info to avoid loops */
        vtop[-1].t = ft & ~(VT_BITFIELD | (-1 << VT_STRUCT_SHIFT));

        /* duplicate destination */
        vdup();
        vtop[-1] = vtop[-2];

        /* mask and shift source */
        vpushi((1 << bit_size) - 1);
        gen_op('&');
        vpushi(bit_pos);
        gen_op(TOK_SHL);
        /* load destination, mask and or with source */
        vswap();
        vpushi(~(((1 << bit_size) - 1) << bit_pos));
        gen_op('&');
        gen_op('|');
        /* store result */
        vstore();
    } else {
#ifdef CONFIG_TCC_BCHECK
        /* bound check case */
        if (vtop[-1].r & VT_MUSTBOUND) {
            vswap();
            gbound();
            vswap();
        }
#endif
        rc = RC_INT;
        if (is_float(ft))
            rc = RC_FLOAT;
        r = gv(rc);  /* generate value */
        /* if lvalue was saved on stack, must read it */
        if ((vtop[-1].r & VT_VALMASK) == VT_LLOCAL) {
            SValue sv;
            t = get_reg(RC_INT);
            sv.t = VT_INT;
            sv.r = VT_LOCAL | VT_LVAL;
            sv.c.ul = vtop[-1].c.ul;
            load(t, &sv);
            vtop[-1].r = t | VT_LVAL;
        }
        store(r, vtop - 1);
        /* two word case handling : store second register at word + 4 */
        if ((ft & VT_BTYPE) == VT_LLONG) {
            vswap();
            /* convert to int to increment easily */
            vtop->t = VT_INT;
            gaddrof();
            vpushi(4);
            gen_op('+');
            vtop->r |= VT_LVAL;
            vswap();
            /* XXX: it works because r2 is spilled last ! */
            store(vtop->r2, vtop - 1);
        }
        vswap();
        vtop--; /* NOT vpop() because on x86 it would flush the fp stack */
        vtop->r |= delayed_cast;
    }
}

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

/* Parse GNUC __attribute__ extension. Currently, the following
   extensions are recognized:
   - aligned(n) : set data/function alignment.
   - section(x) : generate data/code in this section.
   - unused : currently ignored, but may be used someday.
 */
void parse_attribute(AttributeDef *ad)
{
    int t, n;

    next();
    skip('(');
    skip('(');
    while (tok != ')') {
        if (tok < TOK_IDENT)
            expect("attribute name");
        t = tok;
        next();
        switch(t) {
        case TOK_SECTION:
        case TOK___SECTION__:
            skip('(');
            if (tok != TOK_STR)
                expect("section name");
            ad->section = find_section(tokc.ts->str);
            next();
            skip(')');
            break;
        case TOK_ALIGNED:
        case TOK___ALIGNED__:
            skip('(');
            n = expr_const();
            if (n <= 0 || (n & (n - 1)) != 0) 
                error("alignment must be a positive power of two");
            ad->aligned = n;
            skip(')');
            break;
        case TOK_UNUSED:
        case TOK___UNUSED__:
            /* currently, no need to handle it because tcc does not
               track unused objects */
            break;
        case TOK_NORETURN:
        case TOK___NORETURN__:
            /* currently, no need to handle it because tcc does not
               track unused objects */
            break;
        case TOK_CDECL:
        case TOK___CDECL:
        case TOK___CDECL__:
            ad->func_call = FUNC_CDECL;
            break;
        case TOK_STDCALL:
        case TOK___STDCALL:
        case TOK___STDCALL__:
            ad->func_call = FUNC_STDCALL;
            break;
        default:
            warning("'%s' attribute ignored", get_tok_str(t, NULL));
            /* skip parameters */
            /* XXX: skip parenthesis too */
            if (tok == '(') {
                next();
                while (tok != ')' && tok != -1)
                    next();
                next();
            }
            break;
        }
        if (tok != ',')
            break;
        next();
    }
    skip(')');
    skip(')');
}

/* enum/struct/union declaration */
int struct_decl(int u)
{
    int a, t, b, v, size, align, maxalign, c, offset;
    int bit_size, bit_pos, bsize, bt, lbit_pos;
    Sym *s, *ss, **ps;
    AttributeDef ad;

    a = tok; /* save decl type */
    next();
    if (tok != '{') {
        v = tok;
        next();
        /* struct already defined ? return it */
        /* XXX: check consistency */
        s = sym_find(v | SYM_STRUCT);
        if (s) {
            if (s->t != a)
                error("invalid type");
            goto do_decl;
        }
    } else {
        v = anon_sym++;
    }
    s = sym_push(v | SYM_STRUCT, a, 0, 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;
        bit_pos = 0;
        offset = 0;
        while (1) {
            if (a == TOK_ENUM) {
                v = tok;
                next();
                if (tok == '=') {
                    next();
                    c = expr_const();
                }
                /* enum symbols have static storage */
                sym_push(v, VT_STATIC | VT_INT, VT_CONST, c);
                if (tok == ',')
                    next();
                c++;
            } else {
                parse_btype(&b, &ad);
                while (1) {
                    bit_size = -1;
                    v = 0;
                    if (tok != ':') {
                        t = type_decl(&ad, &v, b, TYPE_DIRECT);
                        if ((t & VT_BTYPE) == VT_FUNC ||
                            (t & (VT_TYPEDEF | VT_STATIC | VT_EXTERN)))
                            error("invalid type for '%s'", 
                                  get_tok_str(v, NULL));
                    } else {
                        t = b;
                    }
                    if (tok == ':') {
                        next();
                        bit_size = expr_const();
                        /* XXX: handle v = 0 case for messages */
                        if (bit_size < 0)
                            error("negative width in bit-field '%s'", 
                                  get_tok_str(v, NULL));
                        if (v && bit_size == 0)
                            error("zero width for bit-field '%s'", 
                                  get_tok_str(v, NULL));
                    }
                    size = type_size(t, &align);
                    lbit_pos = 0;
                    if (bit_size >= 0) {
                        bt = t & VT_BTYPE;
                        if (bt != VT_INT && 
                            bt != VT_BYTE && 
                            bt != VT_SHORT)
                            error("bitfields must have scalar type");
                        bsize = size * 8;
                        if (bit_size > bsize) {
                            error("width of '%s' exceeds its type",
                                  get_tok_str(v, NULL));
                        } else if (bit_size == bsize) {
                            /* no need for bit fields */
                            bit_pos = 0;
                        } else if (bit_size == 0) {
                            /* XXX: what to do if only padding in a
                               structure ? */
                            /* zero size: means to pad */
                            if (bit_pos > 0)
                                bit_pos = bsize;
                        } else {
                            /* we do not have enough room ? */
                            if ((bit_pos + bit_size) > bsize)
                                bit_pos = 0;
                            lbit_pos = bit_pos;
                            /* XXX: handle LSB first */
                            t |= VT_BITFIELD | 
                                (bit_pos << VT_STRUCT_SHIFT) |
                                (bit_size << (VT_STRUCT_SHIFT + 6));
                            bit_pos += bit_size;
                        }
                    } else {
                        bit_pos = 0;
                    }
                    if (v) {
                        /* add new memory data only if starting
                           bit field */
                        if (lbit_pos == 0) {
                            if (a == TOK_STRUCT) {
                                c = (c + align - 1) & -align;
                                offset = c;
                                c += size;
                            } else {
                                offset = 0;
                                if (size > c)
                                    c = size;
                            }
                            if (align > maxalign)
                                maxalign = align;
                        }
#if 0
                        printf("add field %s offset=%d", 
                               get_tok_str(v, NULL), offset);
                        if (t & VT_BITFIELD) {
                            printf(" pos=%d size=%d", 
                                   (t >> VT_STRUCT_SHIFT) & 0x3f,
                                   (t >> (VT_STRUCT_SHIFT + 6)) & 0x3f);
                        }
                        printf("\n");
#endif
                        ss = sym_push(v | SYM_FIELD, t, 0, offset);
                        *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. 
 */
int parse_btype(int *type_ptr, AttributeDef *ad)
{
    int t, u, type_found;
    Sym *s;

    memset(ad, 0, sizeof(AttributeDef));
    type_found = 0;
    t = 0;
    while(1) {
        switch(tok) {
            /* basic types */
        case TOK_CHAR:
            u = VT_BYTE;
        basic_type:
            next();
        basic_type1:
            if ((t & VT_BTYPE) != 0)
                error("too many basic types");
            t |= u;
            break;
        case TOK_VOID:
            u = VT_VOID;
            goto basic_type;
        case TOK_SHORT:
            u = VT_SHORT;
            goto basic_type;
        case TOK_INT:
            next();
            break;
        case TOK_LONG:
            next();
            if ((t & VT_BTYPE) == VT_DOUBLE) {
                t = (t & ~VT_BTYPE) | VT_LDOUBLE;
            } else if ((t & VT_BTYPE) == VT_LONG) {
                t = (t & ~VT_BTYPE) | VT_LLONG;
            } else {
                u = VT_LONG;
                goto basic_type1;
            }
            break;
        case TOK_BOOL:
            u = VT_BOOL;
            goto basic_type;
        case TOK_FLOAT:
            u = VT_FLOAT;
            goto basic_type;
        case TOK_DOUBLE:
            next();
            if ((t & VT_BTYPE) == VT_LONG) {
                t = (t & ~VT_BTYPE) | VT_LDOUBLE;
            } else {
                u = VT_DOUBLE;
                goto basic_type1;
            }
            break;
        case TOK_ENUM:
            u = struct_decl(VT_ENUM);
            goto basic_type1;
        case TOK_STRUCT:
        case TOK_UNION:
            u = struct_decl(VT_STRUCT);
            goto basic_type1;

            /* type modifiers */
        case TOK_CONST:
        case TOK_VOLATILE:
        case TOK_REGISTER:
        case TOK_SIGNED:
        case TOK___SIGNED__:
        case TOK_AUTO:
        case TOK_INLINE:
        case TOK___INLINE__:
        case TOK_RESTRICT:
            next();
            break;
        case TOK_UNSIGNED:
            t |= VT_UNSIGNED;
            next();
            break;

            /* storage */
        case TOK_EXTERN:
            t |= VT_EXTERN;
            next();
            break;
        case TOK_STATIC:
            t |= VT_STATIC;
            next();
            break;
        case TOK_TYPEDEF:
            t |= VT_TYPEDEF;
            next();
            break;
            /* GNUC attribute */
        case TOK___ATTRIBUTE__:
            parse_attribute(ad);
            break;
        default:
            s = sym_find(tok);
            if (!s || !(s->t & VT_TYPEDEF))
                goto the_end;
            t |= (s->t & ~VT_TYPEDEF);
            next();
            break;
        }
        type_found = 1;
    }
the_end:
    /* long is never used as type */
    if ((t & VT_BTYPE) == VT_LONG)
        t = (t & ~VT_BTYPE) | VT_INT;
    *type_ptr = t;
    return type_found;
}

int post_type(int t, AttributeDef *ad)
{
    int p, n, pt, l, t1;
    Sym **plast, *s, *first;
    AttributeDef ad1;

    if (tok == '(') {
        /* function declaration */
        next();
        l = 0;
        first = NULL;
        plast = &first;
        while (tok != ')') {
            /* read param name and compute offset */
            if (l != FUNC_OLD) {
                if (!parse_btype(&pt, &ad1)) {
                    if (l) {
                        error("invalid type");
                    } else {
                        l = FUNC_OLD;
                        goto old_proto;
                    }
                }
                l = FUNC_NEW;
                if ((pt & VT_BTYPE) == VT_VOID && tok == ')')
                    break;
                pt = type_decl(&ad1, &n, pt, TYPE_DIRECT | TYPE_ABSTRACT);
                if ((pt & VT_BTYPE) == VT_VOID)
                    error("parameter declared as void");
            } 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, 0);
            *plast = s;
            plast = &s->next;
            if (tok == ',') {
                next();
                if (l == FUNC_NEW && tok == TOK_DOTS) {
                    l = FUNC_ELLIPSIS;
                    next();
                    break;
                }
            }
        }
        /* if no parameters, then old type prototype */
        if (l == 0)
            l = FUNC_OLD;
        skip(')');
        t1 = t & (VT_TYPEDEF | VT_STATIC | VT_EXTERN);
        t = post_type(t & ~(VT_TYPEDEF | VT_STATIC | VT_EXTERN), ad);
        /* we push a anonymous symbol which will contain the function prototype */
        p = anon_sym++;
        s = sym_push(p, t, ad->func_call, l);
        s->next = first;
        t = t1 | 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 */
        t1 = t & (VT_TYPEDEF | VT_STATIC | VT_EXTERN);
        t = post_type(t & ~(VT_TYPEDEF | VT_STATIC | VT_EXTERN), ad);
        
        /* we push a anonymous symbol which will contain the array
           element type */
        p = anon_sym++;
        sym_push(p, t, 0, n);
        t = t1 | VT_ARRAY | VT_PTR | (p << VT_STRUCT_SHIFT);
    }
    return t;
}

/* Read a type declaration (except basic type), and return the
   type. 'td' is a bitmask indicating which kind of type decl is
   expected. 't' should contain the basic type. 'ad' is the attribute
   definition of the basic type. It can be modified by type_decl(). */
int type_decl(AttributeDef *ad, int *v, int t, int td)
{
    int u, p;
    Sym *s;

    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();
        /* XXX: this is not correct to modify 'ad' at this point, but
           the syntax is not clear */
        if (tok == TOK___ATTRIBUTE__)
            parse_attribute(ad);
        u = type_decl(ad, 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, ad);
    if (tok == TOK___ATTRIBUTE__)
        parse_attribute(ad);
    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 symbol 'v' of type 'u' */
Sym *external_sym(int v, int u, int r)
{
    Sym *s;

    s = sym_find(v);
    if (!s) {
        /* push forward reference */
        s = sym_push1(&global_stack, 
                      v, u | VT_EXTERN, 0);
        s->r = r | VT_CONST | VT_SYM;
    }
    return s;
}

/* compute the lvalue VT_LVAL_xxx needed to match type t. */
static int lvalue_type(int t)
{
    int bt, r;
    r = VT_LVAL;
    bt = t & VT_BTYPE;
    if (bt == VT_BYTE)
        r |= VT_LVAL_BYTE;
    else if (bt == VT_SHORT)
        r |= VT_LVAL_SHORT;
    else
        return r;
    if (t & VT_UNSIGNED)
        r |= VT_LVAL_UNSIGNED;
    return r;
}

/* indirection with full error checking and bound check */
static void indir(void)
{
    if ((vtop->t & VT_BTYPE) != VT_PTR)
        expect("pointer");
    if (vtop->r & VT_LVAL)
        gv(RC_INT);
    vtop->t = pointed_type(vtop->t);
    /* an array is never an lvalue */
    if (!(vtop->t & VT_ARRAY)) {
        vtop->r |= lvalue_type(vtop->t);
        /* if bound checking, the referenced pointer must be checked */
        if (do_bounds_check) 
            vtop->r |= VT_MUSTBOUND;
    }
}

/* pass a parameter to a function and do type checking and casting */
void gfunc_param_typed(GFuncContext *gf, Sym *func, Sym *arg)
{
    int func_type;
    func_type = func->c;
    if (func_type == FUNC_OLD ||
        (func_type == FUNC_ELLIPSIS && arg == NULL)) {
        /* default casting : only need to convert float to double */
        if ((vtop->t & VT_BTYPE) == VT_FLOAT)
            gen_cast(VT_DOUBLE);
    } else if (arg == NULL) {
        error("too many arguments to function");
    } else {
        gen_assign_cast(arg->t);
    }
    gfunc_param(gf);
}

void unary(void)
{
    int n, t, ft, fc, align, size, r, data_offset;
    Sym *s;
    GFuncContext gf;
    AttributeDef ad;

    if (tok == TOK_CINT || tok == TOK_CCHAR || tok == TOK_LCHAR) {
        vpushi(tokc.i);
        next();
    } else if (tok == TOK_CUINT) {
        vsetc(VT_INT | VT_UNSIGNED, VT_CONST, &tokc);
        next();
    } else if (tok == TOK_CLLONG) {
        vsetc(VT_LLONG, VT_CONST, &tokc);
        next();
    } else if (tok == TOK_CULLONG) {
        vsetc(VT_LLONG | VT_UNSIGNED, VT_CONST, &tokc);
        next();
    } else if (tok == TOK_CFLOAT) {
        vsetc(VT_FLOAT, VT_CONST, &tokc);
        next();
    } else if (tok == TOK_CDOUBLE) {
        vsetc(VT_DOUBLE, VT_CONST, &tokc);
        next();
    } else if (tok == TOK_CLDOUBLE) {
        vsetc(VT_LDOUBLE, VT_CONST, &tokc);
        next();
    } else if (tok == TOK___FUNC__) {
        void *ptr;
        int len;
        /* special function name identifier */

        len = strlen(funcname) + 1;
        /* generate char[len] type */
        t = VT_ARRAY | mk_pointer(VT_BYTE);
        s = sym_find(((unsigned)t >> VT_STRUCT_SHIFT));
        s->c = len;
        vpush_ref(t, data_section, data_section->data_offset);
        ptr = section_ptr_add(data_section, len);
        memcpy(ptr, funcname, len);
        next();
    } 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);
        data_offset = data_section->data_offset;
        data_offset = (data_offset + align - 1) & -align;
        fc = data_offset;
        /* we must declare it as an array first to use initializer parser */
        t = VT_ARRAY | mk_pointer(t);
        decl_initializer(t, data_section, data_offset, 1, 0);
        data_offset += type_size(t, &align);
        /* XXX: is it correct to put it exactly as an array ? */
        vpush_ref(t, data_section, fc);
        data_section->data_offset = data_offset;
    } else {
        t = tok;
        next();
        if (t == '(') {
            /* cast ? */
            if (parse_btype(&t, &ad)) {
                ft = type_decl(&ad, &n, t, TYPE_ABSTRACT);
                skip(')');
                /* check ISOC99 compound literal */
                if (tok == '{') {
                    /* data is allocated locally by default */
                    if (global_expr)
                        r = VT_CONST;
                    else
                        r = VT_LOCAL;
                    /* all except arrays are lvalues */
                    if (!(ft & VT_ARRAY))
                        r |= lvalue_type(ft);
                    memset(&ad, 0, sizeof(AttributeDef));
                    decl_initializer_alloc(ft, &ad, r, 1, 0, 0);
                } else {
                    unary();
                    gen_cast(ft);
                }
            } else {
                gexpr();
                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. */
            /* arrays can also be used although they are not lvalues */
            if ((vtop->t & VT_BTYPE) != VT_FUNC &&
                !(vtop->t & VT_ARRAY))
                test_lvalue();
            vtop->t = mk_pointer(vtop->t);
            gaddrof();
        } else
        if (t == '!') {
            unary();
            if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) 
                vtop->c.i = !vtop->c.i;
            else if ((vtop->r & VT_VALMASK) == VT_CMP)
                vtop->c.i = vtop->c.i ^ 1;
            else
                vset(VT_INT, VT_JMP, gtst(1, 0));
        } else
        if (t == '~') {
            unary();
            vpushi(-1);
            gen_op('^');
        } else 
        if (t == '+') {
            /* in order to force cast, we add zero */
            unary();
            if ((vtop->t & VT_BTYPE) == VT_PTR)
                error("pointer not accepted for unary plus");
            vpushi(0);
            gen_op('+');
        } else 
        if (t == TOK_SIZEOF) {
            if (tok == '(') {
                next();
                if (parse_btype(&t, &ad)) {
                    t = type_decl(&ad, &n, t, TYPE_ABSTRACT);
                } else {
                    /* XXX: some code could be generated: add eval
                       flag */
                    gexpr();
                    t = vtop->t;
                    vpop();
                }
                skip(')');
            } else {
                unary();
                t = vtop->t;
                vpop();
            }
            vpushi(type_size(t, &t));
        } else
        if (t == TOK_INC || t == TOK_DEC) {
            unary();
            inc(0, t);
        } else if (t == '-') {
            vpushi(0);
            unary();
            gen_op('-');
        } else 
        {
            if (t < TOK_UIDENT)
                expect("identifier");
            s = sym_find(t);
            if (!s) {
                if (tok != '(')
                    error("'%s' undeclared", get_tok_str(t, NULL));
                /* for simple function calls, we tolerate undeclared
                   external reference to int() function */
                s = external_sym(t, func_old_type, 0); 
            }
            vset(s->t, s->r, s->c);
            /* if forward reference, we must point to s */
            if (vtop->r & VT_SYM)
                vtop->c.sym = 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();
            gaddrof();
            next();
            /* expect pointer on structure */
            if ((vtop->t & VT_BTYPE) != VT_STRUCT)
                expect("struct or union");
            s = sym_find(((unsigned)vtop->t >> VT_STRUCT_SHIFT) | SYM_STRUCT);
            /* find field */
            tok |= SYM_FIELD;
            while ((s = s->next) != NULL) {
                if (s->v == tok)
                    break;
            }
            if (!s)
                error("field not found");
            /* add field offset to pointer */
            vtop->t = char_pointer_type; /* change type to 'char *' */
            vpushi(s->c);
            gen_op('+');
            /* change type to field type, and set to lvalue */
            vtop->t = s->t;
            /* an array is never an lvalue */
            if (!(vtop->t & VT_ARRAY))
                vtop->r |= lvalue_type(vtop->t);
            next();
        } else if (tok == '[') {
            next();
            gexpr();
            gen_op('+');
            indir();
            skip(']');
        } else if (tok == '(') {
            SValue ret;
            Sym *sa;

            /* function call  */
            if ((vtop->t & VT_BTYPE) != VT_FUNC) {
                /* pointer test (no array accepted) */
                if ((vtop->t & (VT_BTYPE | VT_ARRAY)) == VT_PTR) {
                    vtop->t = pointed_type(vtop->t);
                    if ((vtop->t & VT_BTYPE) != VT_FUNC)
                        goto error_func;
                } else {
                error_func:
                    expect("function pointer");
                }
            } else {
                vtop->r &= ~VT_LVAL; /* no lvalue */
            }
            /* get return type */
            s = sym_find((unsigned)vtop->t >> VT_STRUCT_SHIFT);
            save_regs(0); /* save used temporary registers */
            gfunc_start(&gf, s->r);
            next();
            sa = s->next; /* first parameter */
#ifdef INVERT_FUNC_PARAMS
            {
                int parlevel;
                Sym *args, *s1;
                ParseState saved_parse_state;
                TokenString str;
                
                /* read each argument and store it on a stack */
                /* XXX: merge it with macro args ? */
                args = NULL;
                if (tok != ')') {
                    for(;;) {
                        tok_str_new(&str);
                        parlevel = 0;
                        while ((parlevel > 0 || (tok != ')' && tok != ',')) && 
                               tok != -1) {
                            if (tok == '(')
                                parlevel++;
                            else if (tok == ')')
                                parlevel--;
                            tok_str_add_tok(&str);
                            next();
                        }
                        tok_str_add(&str, -1); /* end of file added */
                        tok_str_add(&str, 0);
                        s1 = sym_push2(&args, 0, 0, (int)str.str);
                        s1->next = sa; /* add reference to argument */
                        if (sa)
                            sa = sa->next;
                        if (tok == ')')
                            break;
                        skip(',');
                    }
                }
                
                /* now generate code in reverse order by reading the stack */
                save_parse_state(&saved_parse_state);
                while (args) {
                    macro_ptr = (int *)args->c;
                    next();
                    expr_eq();
                    if (tok != -1)
                        expect("',' or ')'");
                    gfunc_param_typed(&gf, s, args->next);
                    s1 = args->prev;
                    free((int *)args->c);
                    free(args);
                    args = s1;
                }
                restore_parse_state(&saved_parse_state);
            }
#endif
            /* compute first implicit argument if a structure is returned */
            if ((s->t & VT_BTYPE) == VT_STRUCT) {
                /* get some space for the returned structure */
                size = type_size(s->t, &align);
                loc = (loc - size) & -align;
                ret.t = s->t;
                ret.r = VT_LOCAL | VT_LVAL;
                /* pass it as 'int' to avoid structure arg passing
                   problems */
                vset(VT_INT, VT_LOCAL, loc);
                ret.c = vtop->c;
                gfunc_param(&gf);
            } else {
                ret.t = s->t; 
                ret.r2 = VT_CONST;
                /* return in register */
                if (is_float(ret.t)) {
                    ret.r = REG_FRET; 
                } else {
                    if ((ret.t & VT_BTYPE) == VT_LLONG)
                        ret.r2 = REG_LRET;
                    ret.r = REG_IRET;
                }
                ret.c.i = 0;
            }
#ifndef INVERT_FUNC_PARAMS
            if (tok != ')') {
                for(;;) {
                    expr_eq();
                    gfunc_param_typed(&gf, s, sa);
                    if (sa)
                        sa = sa->next;
                    if (tok == ')')
                        break;
                    skip(',');
                }
            }
#endif
            if (sa)
                error("too few arguments to function");
            skip(')');
            gfunc_call(&gf);
            /* return value */
            vsetc(ret.t, ret.r, &ret.c);
            vtop->r2 = ret.r2;
        } else {
            break;
        }
    }
}

void uneq(void)
{
    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();
        t = tok;
        next();
        if (t == '=') {
            expr_eq();
        } else {
            vdup();
            expr_eq();
            gen_op(t & 0x7f);
        }
        vstore();
    }
}

void sum(int 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)) {
            t = tok;
            next();
            sum(l);
            gen_op(t);
       }
    }
}

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

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

void eor(void)
{
    int t;

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

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

    if (const_wanted) {
        sum(10);
        if (tok == '?') {
            c = vtop->c.i;
            vpop();
            next();
            gexpr();
            t = vtop->c.i;
            vpop();
            skip(':');
            expr_eq();
            if (c)
                vtop->c.i = t;
        }
    } else {
        eor();
        if (tok == '?') {
            next();
            save_regs(1); /* we need to save all registers here except
                             at the top because it is a branch point */
            t = gtst(1, 0);
            gexpr();
            /* XXX: long long handling ? */
            rc = RC_INT;
            if (is_float(vtop->t))
                rc = RC_FLOAT;
            r1 = gv(rc);
            vtop--; /* no vpop so that FP stack is not flushed */
            skip(':');
            u = gjmp(0);

            gsym(t);
            expr_eq();
            r2 = gv(rc);
            move_reg(r1, r2);
            vtop->r = r1;
            gsym(u);
        }
    }
}

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

/* parse a constant expression and return value in vtop */
void expr_const1(void)
{
    int a;
    a = const_wanted;
    const_wanted = 1;
    expr_eq();
    if ((vtop->r & (VT_VALMASK | VT_LVAL)) != VT_CONST)
        expect("constant");
    const_wanted = a;
}

/* parse an integer constant and return its value */
int expr_const(void)
{
    int c;
    expr_const1();
    c = vtop->c.i;
    vpop();
    return c;
}

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

    /* fast test first */
    if (tok < TOK_UIDENT)
        return 0;
    /* no need to save tokc since we expect an identifier */
    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;

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

    if (tok == TOK_IF) {
        /* if test */
        next();
        skip('(');
        gexpr();
        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('(');
        gexpr();
        skip(')');
        a = gtst(1, 0);
        b = 0;
        block(&a, &b, case_sym, def_sym, case_reg);
        gjmp_addr(d);
        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 != ';') {
            gexpr();
            gen_assign_cast(func_vt);
            if ((func_vt & VT_BTYPE) == 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();
                vswap();
                /* copy structure value to pointer */
                vstore();
            } else if (is_float(func_vt)) {
                gv(RC_FRET);
            } else {
                gv(RC_IRET);
            }
            vtop--; /* NOT vpop() because on x86 it would flush the fp stack */
        }
        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 != ';') {
            gexpr();
            vpop();
        }
        skip(';');
        d = ind;
        c = ind;
        a = 0;
        b = 0;
        if (tok != ';') {
            gexpr();
            a = gtst(1, 0);
        }
        skip(';');
        if (tok != ')') {
            e = gjmp(0);
            c = ind;
            gexpr();
            vpop();
            gjmp_addr(d);
            gsym(e);
        }
        skip(')');
        block(&a, &b, case_sym, def_sym, case_reg);
        gjmp_addr(c);
        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);
        gexpr();
        c = gtst(0, 0);
        gsym_addr(c, d);
        skip(')');
        gsym(a);
        skip(';');
    } else
    if (tok == TOK_SWITCH) {
        next();
        skip('(');
        gexpr();
        /* XXX: other types than integer */
        case_reg = gv(RC_INT);
        vpop();
        skip(')');
        a = 0;
        b = gjmp(0); /* jump to first case */
        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) {
        int v1, v2;
        if (!case_sym)
            expect("switch");
        next();
        v1 = expr_const();
        v2 = v1;
        if (gnu_ext && tok == TOK_DOTS) {
            next();
            v2 = expr_const();
            if (v2 < v1)
                warning("empty case range");
        }
        /* since a case is like a label, we must skip it with a jmp */
        b = gjmp(0);
        gsym(*case_sym);
        vset(VT_INT, case_reg, 0);
        vpushi(v1);
        if (v1 == v2) {
            gen_op(TOK_EQ);
            *case_sym = gtst(1, 0);
        } else {
            gen_op(TOK_GE);
            *case_sym = gtst(1, 0);
            vset(VT_INT, case_reg, 0);
            vpushi(v2);
            gen_op(TOK_LE);
            *case_sym = gtst(1, *case_sym);
        }
        gsym(b);
        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, LABEL_FORWARD, 0);
        /* label already defined */
        if (s->t & LABEL_FORWARD) 
            s->c = gjmp(s->c);
        else
            gjmp_addr(s->c);
        next();
        skip(';');
    } else {
        b = is_label();
        if (b) {
            /* label case */
            s = sym_find1(&label_stack, b);
            if (s) {
                if (!(s->t & LABEL_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 != ';') {
                gexpr();
                vpop();
            }
            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, Section *sec, unsigned long 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_BTYPE) != 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_TYPE);
            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_TYPE);
            c += f->c;
        }
    }
    decl_initializer(t, sec, c, 0, size_only);
}

#define EXPR_VAL   0
#define EXPR_CONST 1
#define EXPR_ANY   2

/* store a value or an expression directly in global data or in local array */
void init_putv(int t, Section *sec, unsigned long c, 
               int v, int expr_type)
{
    int saved_global_expr, bt;
    void *ptr;

    switch(expr_type) {
    case EXPR_VAL:
        vpushi(v);
        break;
    case EXPR_CONST:
        /* compound literals must be allocated globally in this case */
        saved_global_expr = global_expr;
        global_expr = 1;
        expr_const1();
        global_expr = saved_global_expr;
        break;
    case EXPR_ANY:
        expr_eq();
        break;
    }
    
    if (sec) {
        /* XXX: not portable */
        /* XXX: generate error if incorrect relocation */
        gen_assign_cast(t);
        bt = t & VT_BTYPE;
        ptr = sec->data + c;
        if ((vtop->r & VT_SYM) &&
            (bt == VT_BYTE ||
             bt == VT_SHORT ||
             bt == VT_DOUBLE ||
             bt == VT_LDOUBLE ||
             bt == VT_LLONG))
            error("initializer element is not computable at load time");
        switch(bt) {
        case VT_BYTE:
            *(char *)ptr = vtop->c.i;
            break;
        case VT_SHORT:
            *(short *)ptr = vtop->c.i;
            break;
        case VT_DOUBLE:
            *(double *)ptr = vtop->c.d;
            break;
        case VT_LDOUBLE:
            *(long double *)ptr = vtop->c.ld;
            break;
        case VT_LLONG:
            *(long long *)ptr = vtop->c.ll;
            break;
        default:
            if (vtop->r & VT_SYM) {
                greloc(sec, vtop->c.sym, c, R_DATA_32);
                *(int *)ptr = 0;
            } else {
                *(int *)ptr = vtop->c.i;
            }
            break;
        }
        vtop--;
    } else {
        vset(t, VT_LOCAL, c);
        vswap();
        vstore();
        vpop();
    }
}

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

    if (sec) {
        /* nothing to do because globals are already set to zero */
    } else {
        gfunc_start(&gf, FUNC_CDECL);
        vpushi(size);
        gfunc_param(&gf);
        vpushi(0);
        gfunc_param(&gf);
        vset(VT_INT, VT_LOCAL, c);
        gfunc_param(&gf);
        vpush_sym(func_old_type, TOK_memset);
        gfunc_call(&gf);
    }
}

/* 't' contains the type and storage info. 'c' is the offset of the
   object in section 'sec'. If 'sec' is NULL, it means stack based
   allocation. '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, Section *sec, unsigned long c, int first, int size_only)
{
    int index, array_length, n, no_oblock, nb, parlevel, i;
    int t1, size1, align1, expr_type;
    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_BTYPE) == VT_INT) ||
            (tok == TOK_STR &&
             (t1 & VT_BTYPE) == VT_BYTE)) {
            /* XXX: move multiple string parsing in parser ? */
            while (tok == TOK_STR || tok == TOK_LSTR) {
                ts = tokc.ts;
                /* 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, sec, c + (array_length + i) * size1, 
                                  ts->str[i], EXPR_VAL);
                    }
                }
                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, sec, c + (array_length * size1), 0, EXPR_VAL);
                }
                array_length++;
            }
        } else {
            index = 0;
            while (tok != '}') {
                decl_designator(t, sec, 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, sec, 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, sec, c + array_length * size1, 
                      (n - array_length) * size1);
        }
        /* patch type size if needed */
        if (n < 0)
            s->c = array_length;
    } else if ((t & VT_BTYPE) == 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, sec, c, NULL, &f, size_only);
            /* fill with zero between fields */
            index = f->c;
            if (!size_only && array_length < index) {
                init_putz(t, sec, 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, sec, c + array_length, 
                      n - array_length);
        }
        skip('}');
    } else if (tok == '{') {
        next();
        decl_initializer(t, sec, 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 {
        /* currently, we always use constant expression for globals
           (may change for scripting case) */
        expr_type = EXPR_CONST;
        if (!sec)
            expr_type = EXPR_ANY;
        init_putv(t, sec, c, 0, expr_type);
    }
}

/* parse an initializer for type 't' if 'has_init' is true, and
   allocate space in local or global data space ('r' is either
   VT_LOCAL or VT_CONST). If 'v' is non zero, then an associated
   variable 'v' of scope 'scope' is declared before initializers are
   parsed. If 'v' is zero, then a reference to the new object is put
   in the value stack. */
void decl_initializer_alloc(int t, AttributeDef *ad, int r, int has_init,
                            int v, int scope)
{
    int size, align, addr, data_offset;
    int level;
    ParseState saved_parse_state;
    TokenString init_str;
    Section *sec;

    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 */
    tok_str_new(&init_str);
    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("unexpected end of file in initializer");
            tok_str_add_tok(&init_str);
            if (tok == '{')
                level++;
            else if (tok == '}') {
                if (level == 0)
                    break;
                level--;
            }
            next();
        }
        tok_str_add(&init_str, -1);
        tok_str_add(&init_str, 0);
        
        /* compute size */
        save_parse_state(&saved_parse_state);

        macro_ptr = init_str.str;
        next();
        decl_initializer(t, NULL, 0, 1, 1);
        /* prepare second initializer parsing */
        macro_ptr = init_str.str;
        next();
        
        /* if still unknown size, error */
        size = type_size(t, &align);
        if (size < 0) 
            error("unknown type size");
    }
    /* take into account specified alignment if bigger */
    if (ad->aligned > align)
        align = ad->aligned;
    if ((r & VT_VALMASK) == VT_LOCAL) {
        sec = NULL;
        if (do_bounds_check && (t & VT_ARRAY)) 
            loc--;
#ifdef TCC_TARGET_IL
        /* XXX: ugly patch to allocate local variables for IL, just
           for testing */
        addr = loc;
        loc++;
#else
        loc = (loc - size) & -align;
        addr = loc;
#endif
        /* handles bounds */
        /* XXX: currently, since we do only one pass, we cannot track
           '&' operators, so we add only arrays */
        if (do_bounds_check && (t & VT_ARRAY)) {
            unsigned long *bounds_ptr;
            /* add padding between regions */
            loc--;
            /* then add local bound info */
            bounds_ptr = section_ptr_add(lbounds_section, 2 * sizeof(unsigned long));
            bounds_ptr[0] = addr;
            bounds_ptr[1] = size;
        }
    } else {
        /* compute section */
        sec = ad->section;
        if (!sec) {
            if (has_init)
                sec = data_section;
            else
                sec = bss_section;
        }
        data_offset = sec->data_offset;
        data_offset = (data_offset + align - 1) & -align;
        addr = data_offset;
        /* very important to increment global pointer at this time
           because initializers themselves can create new initializers */
        data_offset += size;
        /* add padding if bound check */
        if (do_bounds_check)
            data_offset++;
        sec->data_offset = data_offset;
    }
    if (!sec) {
        if (v) {
            /* local variable */
            sym_push(v, t, r, addr);
        } else {
            /* push local reference */
            vset(t, r, addr);
        }
    } else {
        Sym *sym;
        
        if (v) {
            if (scope == VT_CONST) {
                /* global scope: see if already defined */
                sym = sym_find(v);
                if (!sym)
                    goto do_def;
                if (!is_compatible_types(sym->t, t))
                    error("incompatible types for redefinition of '%s'", 
                          get_tok_str(v, NULL));
                if (!(sym->t & VT_EXTERN))
                    error("redefinition of '%s'", get_tok_str(v, NULL));
                sym->t &= ~VT_EXTERN;
            } else {
            do_def:
                sym = sym_push(v, t, r | VT_SYM, 0);
            }
            put_extern_sym(sym, sec, addr);
        } else {
            CValue cval;

            /* push global reference */
            sym = get_sym_ref(t, sec, addr, 0);
            cval.sym = sym;
            vsetc(t, VT_CONST | VT_SYM, &cval);
        }

        /* handles bounds now because the symbol must be defined
           before for the relocation */
        if (do_bounds_check) {
            unsigned long *bounds_ptr;

            greloc(bounds_section, sym, bounds_section->data_offset, R_DATA_32);
            /* then add global bound info */
            bounds_ptr = section_ptr_add(bounds_section, 2 * sizeof(long));
            bounds_ptr[0] = 0; /* relocated */
            bounds_ptr[1] = size;
        }
    }
    if (has_init) {
        decl_initializer(t, sec, addr, 1, 0);
        /* restore parse state if needed */
        if (init_str.str) {
            free(init_str.str);
            restore_parse_state(&saved_parse_state);
        }
    }
}

void put_func_debug(Sym *sym)
{
    char buf[512];

    /* stabs info */
    /* XXX: we put here a dummy type */
    snprintf(buf, sizeof(buf), "%s:%c1", 
             funcname, sym->t & VT_STATIC ? 'f' : 'F');
    put_stabs_r(buf, N_FUN, 0, file->line_num, 0,
                cur_text_section, sym->c);
    func_ind = ind;
    last_ind = 0;
    last_line_num = 0;
}

/* not finished : try to put some local vars in registers */
//#define CONFIG_REG_VARS

#ifdef CONFIG_REG_VARS
void add_var_ref(int t)
{
    printf("%s:%d: &%s\n", 
           file->filename, file->line_num,
           get_tok_str(t, NULL));
}

/* first pass on a function with heuristic to extract variable usage
   and pointer references to local variables for register allocation */
void analyse_function(void)
{
    int level, t;

    for(;;) {
        if (tok == -1)
            break;
        /* any symbol coming after '&' is considered as being a
           variable whose reference is taken. It is highly unaccurate
           but it is difficult to do better without a complete parse */
        if (tok == '&') {
            next();
            /* if '& number', then no need to examine next tokens */
            if (tok == TOK_CINT ||
                tok == TOK_CUINT ||
                tok == TOK_CLLONG ||
                tok == TOK_CULLONG) {
                continue;
            } else if (tok >= TOK_UIDENT) {
                /* if '& ident [' or '& ident ->', then ident address
                   is not needed */
                t = tok;
                next();
                if (tok != '[' && tok != TOK_ARROW)
                    add_var_ref(t);
            } else {
                level = 0;
                while (tok != '}' && tok != ';' && 
                       !((tok == ',' || tok == ')') && level == 0)) {
                    if (tok >= TOK_UIDENT) {
                        add_var_ref(tok);
                    } else if (tok == '(') {
                        level++;
                    } else if (tok == ')') {
                        level--;
                    }
                    next();
                }
            }
        } else {
            next();
        }
    }
}
#endif

/* 'l' is VT_LOCAL or VT_CONST to define default storage type */
void decl(int l)
{
    int t, b, v, has_init, r;
    Sym *sym;
    AttributeDef ad;
    
    while (1) {
        if (!parse_btype(&b, &ad)) {
            /* 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_BTYPE) == VT_ENUM ||
             (b & VT_BTYPE) == VT_STRUCT) && 
            tok == ';') {
            /* we accept no variable after */
            next();
            continue;
        }
        while (1) { /* iterate thru each declaration */
            t = type_decl(&ad, &v, b, TYPE_DIRECT);
#if 0
            {
                char buf[500];
                type_to_str(buf, sizeof(buf), t, get_tok_str(v, NULL));
                printf("type = '%s'\n", buf);
            }
#endif
            if (tok == '{') {
#ifdef CONFIG_REG_VARS
                TokenString func_str;
                ParseState saved_parse_state;
                int block_level;
#endif

                if (l == VT_LOCAL)
                    error("cannot use local functions");
                if (!(t & VT_FUNC))
                    expect("function definition");

#ifdef CONFIG_REG_VARS
                /* parse all function code and record it */

                tok_str_new(&func_str);
                
                block_level = 0;
                for(;;) {
                    int t;
                    if (tok == -1)
                        error("unexpected end of file");
                    tok_str_add_tok(&func_str);
                    t = tok;
                    next();
                    if (t == '{') {
                        block_level++;
                    } else if (t == '}') {
                        block_level--;
                        if (block_level == 0)
                            break;
                    }
                }
                tok_str_add(&func_str, -1);
                tok_str_add(&func_str, 0);

                save_parse_state(&saved_parse_state);
    
                macro_ptr = func_str.str;
                next();
                analyse_function();
#endif

                /* compute text section */
                cur_text_section = ad.section;
                if (!cur_text_section)
                    cur_text_section = text_section;
                ind = cur_text_section->data_offset;
                funcname = get_tok_str(v, NULL);
                sym = sym_find(v);
                if (sym) {
                    /* if symbol is already defined, then put complete type */
                    sym->t = t;
                } else {
                    /* put function symbol */
                    sym = sym_push1(&global_stack, v, t, 0);
                }
                put_extern_sym(sym, cur_text_section, ind);
                sym->r = VT_SYM | VT_CONST;
                /* put debug symbol */
                if (do_debug)
                    put_func_debug(sym);
                /* push a dummy symbol to enable local sym storage */
                sym_push1(&local_stack, 0, 0, 0);
                gfunc_prolog(t);
                loc = 0;
                rsym = 0;
#ifdef CONFIG_REG_VARS
                macro_ptr = func_str.str;
                next();
#endif
                block(NULL, NULL, NULL, NULL, 0);
                gsym(rsym);
                gfunc_epilog();
                cur_text_section->data_offset = ind;
                sym_pop(&label_stack, NULL); /* reset label stack */
                sym_pop(&local_stack, NULL); /* reset local stack */
                /* end of function */
                if (do_debug) {
                    put_stabn(N_FUN, 0, 0, ind - func_ind);
                }
                funcname = ""; /* for safety */
                func_vt = VT_VOID; /* for safety */
                ind = 0; /* for safety */

#ifdef CONFIG_REG_VARS
                free(func_str.str);
                restore_parse_state(&saved_parse_state);
#endif
                break;
            } else {
                if (b & VT_TYPEDEF) {
                    /* save typedefed type  */
                    /* XXX: test storage specifiers ? */
                    sym_push(v, t | VT_TYPEDEF, 0, 0);
                } else if ((t & VT_BTYPE) == VT_FUNC) {
                    /* external function definition */
                    external_sym(v, t, 0);
                } else {
                    /* not lvalue if array */
                    r = 0;
                    if (!(t & VT_ARRAY))
                        r |= lvalue_type(t);
                    if (b & VT_EXTERN) {
                        /* external variable */
                        external_sym(v, t, r);
                    } else {
                        if (t & VT_STATIC)
                            r |= VT_CONST;
                        else
                            r |= l;
                        has_init = (tok == '=');
                        if (has_init)
                            next();
                        decl_initializer_alloc(t, &ad, r, 
                                               has_init, v, l);
                    }
                }
                if (tok != ',') {
                    skip(';');
                    break;
                }
                next();
            }
        }
    }
}

/* compile the C file opened in 'file'. Return non zero if errors. */
static int tcc_compile(TCCState *s)
{
    Sym *define_start;
    char buf[512];
    int p, section_sym;

    funcname = "";
    include_stack_ptr = include_stack;
    ifdef_stack_ptr = ifdef_stack;

    vtop = vstack - 1;
    anon_sym = SYM_FIRST_ANOM; 

    /* file info: full path + filename */
    section_sym = 0; /* avoid warning */
    if (do_debug) {
        section_sym = put_elf_sym(symtab_section, 0, 0, 
                                  ELF32_ST_INFO(STB_LOCAL, STT_SECTION), 0, 
                                  text_section->sh_num, NULL);
        getcwd(buf, sizeof(buf));
        pstrcat(buf, sizeof(buf), "/");
        put_stabs_r(buf, N_SO, 0, 0, 
                    text_section->data_offset, text_section, section_sym);
        put_stabs_r(file->filename, N_SO, 0, 0, 
                    text_section->data_offset, text_section, section_sym);
    }
    /* an elf symbol of type STT_FILE must be put so that STB_LOCAL
       symbols can be safely used */
    put_elf_sym(symtab_section, 0, 0, 
                ELF32_ST_INFO(STB_LOCAL, STT_FILE), 0, 
                SHN_ABS, file->filename);

    /* define common 'char *' type because it is often used internally
       for arrays and struct dereference */
    char_pointer_type = mk_pointer(VT_BYTE);
    /* define an old type function 'int func()' */
    p = anon_sym++;
    sym_push1(&global_stack, p, 0, FUNC_OLD);
    func_old_type = VT_FUNC | (p << VT_STRUCT_SHIFT);

    define_start = define_stack.top;
    inp();
    ch = '\n'; /* needed to parse correctly first preprocessor command */
    next();
    decl(VT_CONST);
    if (tok != -1)
        expect("declaration");

    /* end of translation unit info */
    if (do_debug) {
        put_stabs_r(NULL, N_SO, 0, 0, 
                    text_section->data_offset, text_section, section_sym);
    }

    /* reset define stack, but leave -Dsymbols (may be incorrect if
       they are undefined) */
    sym_pop(&define_stack, define_start); 
    
    sym_pop(&global_stack, NULL);
    
    return 0;
}

int tcc_compile_string(TCCState *s, const char *str)
{
    BufferedFile bf1, *bf = &bf1;
    int ret;

    /* init file structure */
    bf->fd = -1;
    bf->buf_ptr = (char *)str;
    bf->buf_end = (char *)str + strlen(bf->buffer);
    pstrcpy(bf->filename, sizeof(bf->filename), "<string>");
    bf->line_num = 1;
    file = bf;
    
    ret = tcc_compile(s);
    
    /* currently, no need to close */
    return ret;
}

/* define a symbol. A value can also be provided with the '=' operator */
void tcc_define_symbol(TCCState *s, const char *sym, const char *value)
{
    BufferedFile bf1, *bf = &bf1;

    pstrcpy(bf->buffer, IO_BUF_SIZE, sym);
    pstrcat(bf->buffer, IO_BUF_SIZE, " ");
    /* default value */
    if (!value) 
        value = "1";
    pstrcat(bf->buffer, IO_BUF_SIZE, value);

    /* init file structure */
    bf->fd = -1;
    bf->buf_ptr = bf->buffer;
    bf->buf_end = bf->buffer + strlen(bf->buffer);
    bf->filename[0] = '\0';
    bf->line_num = 1;
    file = bf;
    
    include_stack_ptr = include_stack;

    /* parse with define parser */
    inp();
    ch = '\n'; /* needed to parse correctly first preprocessor command */
    next_nomacro();
    parse_define();
    file = NULL;
}

void tcc_undefine_symbol(TCCState *s1, const char *sym)
{
    TokenSym *ts;
    Sym *s;
    ts = tok_alloc(sym, 0);
    s = sym_find1(&define_stack, tok);
    /* undefine symbol by putting an invalid name */
    if (s)
        sym_undef(&define_stack, s);
}

static int put_elf_str(Section *s, const char *sym)
{
    int offset, len;
    char *ptr;

    len = strlen(sym) + 1;
    offset = s->data_offset;
    ptr = section_ptr_add(s, len);
    memcpy(ptr, sym, len);
    return offset;
}

/* elf symbol hashing function */
static unsigned long elf_hash(const unsigned char *name)
{
    unsigned long h = 0, g;
    
    while (*name) {
        h = (h << 4) + *name++;
        g = h & 0xf0000000;
        if (g)
            h ^= g >> 24;
        h &= ~g;
    }
    return h;
}

/* return the symbol number */
static int put_elf_sym(Section *s, 
                       unsigned long value, unsigned long size,
                       int info, int other, int shndx, const char *name)
{
    int name_offset, sym_index;
    int nbuckets, h;
    Elf32_Sym *sym;
    Section *hs;
    
    sym = section_ptr_add(s, sizeof(Elf32_Sym));
    if (name)
        name_offset = put_elf_str(s->link, name);
    else
        name_offset = 0;
    /* XXX: endianness */
    sym->st_name = name_offset;
    sym->st_value = value;
    sym->st_size = size;
    sym->st_info = info;
    sym->st_other = other;
    sym->st_shndx = shndx;
    sym_index = sym - (Elf32_Sym *)s->data;
    hs = s->hash;
    if (hs) {
        int *ptr;
        ptr = section_ptr_add(hs, sizeof(int));
        /* only add global or weak symbols */
        if (ELF32_ST_BIND(info) != STB_LOCAL) {
            /* add another hashing entry */
            nbuckets = ((int *)hs->data)[0];
            h = elf_hash(name) % nbuckets;
            *ptr = ((int *)hs->data)[2 + h];
            ((int *)hs->data)[2 + h] = sym_index;
        } else {
            *ptr = 0;
        }
        /* but still add room for all symbols */
        ((int *)hs->data)[1]++;
    }
    return sym_index;
}

/* find global ELF symbol 'name' and return its index. Return 0 if not
   found. */
static int find_elf_sym(Section *s, const char *name)
{
    Elf32_Sym *sym;
    Section *hs;
    int nbuckets, sym_index, h;
    const char *name1;
    
    hs = s->hash;
    if (!hs)
        return 0;
    nbuckets = ((int *)hs->data)[0];
    h = elf_hash(name) % nbuckets;
    sym_index = ((int *)hs->data)[2 + h];
    while (sym_index != 0) {
        sym = &((Elf32_Sym *)s->data)[sym_index];
        name1 = s->link->data + sym->st_name;
        if (!strcmp(name, name1))
            return sym_index;
        sym_index = ((int *)hs->data)[2 + nbuckets + sym_index];
    }
    return 0;
}

/* return elf symbol value or error */
static unsigned long get_elf_sym_val(const char *name)
{
    int sym_index;
    Elf32_Sym *sym;
    
    sym_index = find_elf_sym(symtab_section, name);
    if (!sym_index)
        error("%s not defined", name);
    sym = &((Elf32_Sym *)symtab_section->data)[sym_index];
    return sym->st_value;
}

/* add an elf symbol : check if it is already defined and patch
   it. Return symbol index. NOTE that sh_num can be SHN_UNDEF. */
static int add_elf_sym(Section *s, unsigned long value, unsigned long size,
                       int info, int sh_num, const char *name)
{
    Elf32_Sym *esym;
    int sym_bind, sym_index, sym_type, esym_bind;

    sym_bind = ELF32_ST_BIND(info);
    sym_type = ELF32_ST_TYPE(info);
        
    if (sym_bind != STB_LOCAL) {
        /* we search global or weak symbols */
        sym_index = find_elf_sym(s, name);
        if (!sym_index)
            goto do_def;
        esym = &((Elf32_Sym *)s->data)[sym_index];
        if (esym->st_shndx != SHN_UNDEF) {
            esym_bind = ELF32_ST_BIND(esym->st_info);
            if (sh_num == SHN_UNDEF) {
                /* ignore adding of undefined symbol if the
                   corresponding symbol is already defined */
            } else if (sym_bind == STB_GLOBAL && esym_bind == STB_WEAK) {
                /* global overrides weak, so patch */
                goto do_patch;
            } else if (sym_bind == STB_WEAK && esym_bind == STB_GLOBAL) {
                /* weak is ignored if already global */
            } else {
#if 0
                printf("new_bind=%d new_shndx=%d last_bind=%d old_shndx=%d\n",
                       sym_bind, sh_num, esym_bind, esym->st_shndx);
#endif
                /* NOTE: we accept that two DLL define the same symbol */
                if (s != dynsymtab_section)
                    error("'%s' defined twice", name);
            }
        } else {
        do_patch:
            esym->st_info = ELF32_ST_INFO(sym_bind, sym_type);
            esym->st_shndx = sh_num;
            esym->st_value = value;
            esym->st_size = size;
        }
    } else {
    do_def:
        sym_index = put_elf_sym(s, value, size, 
                                ELF32_ST_INFO(sym_bind, sym_type), 0, 
                                sh_num, name);
    }
    return sym_index;
}

/* update sym->c so that it points to an external symbol in section
   'section' with value 'value' */
void put_extern_sym(Sym *sym, Section *section, unsigned long value)
{
    int sym_type, sym_bind, sh_num, info;
    Elf32_Sym *esym;
    const char *name;
    char buf[32];

    if (section)
        sh_num = section->sh_num;
    else
        sh_num = SHN_UNDEF;
    if (!sym->c) {
        if ((sym->t & VT_BTYPE) == VT_FUNC)
            sym_type = STT_FUNC;
        else
            sym_type = STT_OBJECT;
        if (sym->t & VT_STATIC)
            sym_bind = STB_LOCAL;
        else
            sym_bind = STB_GLOBAL;
        
        name = get_tok_str(sym->v, NULL);
#ifdef CONFIG_TCC_BCHECK
        if (do_bounds_check) {
            /* if bound checking is activated, we change some function
               names by adding the "__bound" prefix */
            switch(sym->v) {
            case TOK_malloc: 
            case TOK_free: 
            case TOK_realloc: 
            case TOK_memalign: 
            case TOK_calloc: 
            case TOK_memcpy: 
            case TOK_memmove:
            case TOK_memset:
            case TOK_strlen:
            case TOK_strcpy:
                strcpy(buf, "__bound_");
                strcat(buf, name);
                name = buf;
                break;
            }
        }
#endif
        info = ELF32_ST_INFO(sym_bind, sym_type);
        sym->c = add_elf_sym(symtab_section, value, 0, info, sh_num, name);
    } else {
        esym = &((Elf32_Sym *)symtab_section->data)[sym->c];
        esym->st_value = value;
        esym->st_shndx = sh_num;
    }
}

/* put relocation */
static void put_elf_reloc(Section *symtab, Section *s, unsigned long offset,
                          int type, int symbol)
{
    char buf[256];
    Section *sr;
    Elf32_Rel *rel;

    sr = s->reloc;
    if (!sr) {
        /* if no relocation section, create it */
        snprintf(buf, sizeof(buf), ".rel%s", s->name);
        /* if the symtab is allocated, then we consider the relocation
           are also */
        sr = new_section(buf, SHT_REL, symtab->sh_flags);
        sr->sh_entsize = sizeof(Elf32_Rel);
        sr->link = symtab;
        sr->sh_info = s->sh_num;
        s->reloc = sr;
    }
    rel = section_ptr_add(sr, sizeof(Elf32_Rel));
    rel->r_offset = offset;
    rel->r_info = ELF32_R_INFO(symbol, type);
}

/* put stab debug information */

typedef struct {
    unsigned long n_strx;         /* index into string table of name */
    unsigned char n_type;         /* type of symbol */
    unsigned char n_other;        /* misc info (usually empty) */
    unsigned short n_desc;        /* description field */
    unsigned long n_value;        /* value of symbol */
} Stab_Sym;

static void put_stabs(const char *str, int type, int other, int desc, 
                      unsigned long value)
{
    Stab_Sym *sym;

    sym = section_ptr_add(stab_section, sizeof(Stab_Sym));
    if (str) {
        sym->n_strx = put_elf_str(stabstr_section, str);
    } else {
        sym->n_strx = 0;
    }
    sym->n_type = type;
    sym->n_other = other;
    sym->n_desc = desc;
    sym->n_value = value;
}

static void put_stabs_r(const char *str, int type, int other, int desc, 
                        unsigned long value, Section *sec, int sym_index)
{
    put_stabs(str, type, other, desc, value);
    put_elf_reloc(symtab_section, stab_section, 
                  stab_section->data_offset - sizeof(unsigned long),
                  R_DATA_32, sym_index);
}

static void put_stabn(int type, int other, int desc, int value)
{
    put_stabs(NULL, type, other, desc, value);
}

static void put_stabd(int type, int other, int desc)
{
    put_stabs(NULL, type, other, desc, 0);
}

/* In an ELF file symbol table, the local symbols must appear below
   the global and weak ones. Since TCC cannot sort it while generating
   the code, we must do it after. All the relocation tables are also
   modified to take into account the symbol table sorting */
static void sort_syms(Section *s)
{
    int *old_to_new_syms;
    Elf32_Sym *new_syms;
    int nb_syms, i;
    Elf32_Sym *p, *q;
    Elf32_Rel *rel, *rel_end;
    Section *sr;
    int type, sym_index;

    nb_syms = s->data_offset / sizeof(Elf32_Sym);
    new_syms = malloc(nb_syms * sizeof(Elf32_Sym));
    if (!new_syms)
        error("memory full");
    old_to_new_syms = malloc(nb_syms * sizeof(int));
    if (!old_to_new_syms)
        error("memory full");
    /* first pass for local symbols */
    p = (Elf32_Sym *)s->data;
    q = new_syms;
    for(i = 0; i < nb_syms; i++) {
        if (ELF32_ST_BIND(p->st_info) == STB_LOCAL) {
            old_to_new_syms[i] = q - new_syms;
            *q++ = *p;
        }
        p++;
    }
    /* save the number of local symbols in section header */
    s->sh_info = q - new_syms;

    /* then second pass for non local symbols */
    p = (Elf32_Sym *)s->data;
    for(i = 0; i < nb_syms; i++) {
        if (ELF32_ST_BIND(p->st_info) != STB_LOCAL) {
            old_to_new_syms[i] = q - new_syms;
            *q++ = *p;
        }
        p++;
    }
    
    /* we copy the new symbols to the old */
    memcpy(s->data, new_syms, nb_syms * sizeof(Elf32_Sym));
    free(new_syms);

    /* now we modify all the relocations */
    for(i = 1; i < nb_sections; i++) {
        sr = sections[i];
        if (sr->sh_type == SHT_REL && sr->link == s) {
            rel_end = (Elf32_Rel *)(sr->data + sr->data_offset);
            for(rel = (Elf32_Rel *)sr->data;
                rel < rel_end;
                rel++) {
                sym_index = ELF32_R_SYM(rel->r_info);
                type = ELF32_R_TYPE(rel->r_info);
                sym_index = old_to_new_syms[sym_index];
                rel->r_info = ELF32_R_INFO(sym_index, type);
            }
        }
    }
    
    free(old_to_new_syms);
}

/* relocate common symbols in the .bss section */
static void relocate_common_syms(void)
{
    Elf32_Sym *sym, *sym_end;
    unsigned long offset, align;
    
    sym_end = (Elf32_Sym *)(symtab_section->data + symtab_section->data_offset);
    for(sym = (Elf32_Sym *)symtab_section->data + 1; 
        sym < sym_end;
        sym++) {
        if (sym->st_shndx == SHN_COMMON) {
            /* align symbol */
            align = sym->st_value;
            offset = bss_section->data_offset;
            offset = (offset + align - 1) & -align;
            sym->st_value = offset;
            sym->st_shndx = bss_section->sh_num;
            offset += sym->st_size;
            bss_section->data_offset = offset;
        }
    }
}

static void *resolve_sym(const char *sym)
{
    return dlsym(NULL, sym);
}

/* relocate symbol table, resolve undefined symbols if do_resolve is
   true and output error if undefined symbol. */
static void relocate_syms(int do_resolve)
{
    Elf32_Sym *sym, *esym, *sym_end;
    int sym_bind, sh_num, sym_index;
    const char *name;
    unsigned long addr;

    sym_end = (Elf32_Sym *)(symtab_section->data + symtab_section->data_offset);
    for(sym = (Elf32_Sym *)symtab_section->data + 1; 
        sym < sym_end;
        sym++) {
        sh_num = sym->st_shndx;
        if (sh_num == SHN_UNDEF) {
            name = strtab_section->data + sym->st_name;
            if (do_resolve) {
                name = symtab_section->link->data + sym->st_name;
                addr = (unsigned long)resolve_sym(name);
                if (addr) {
                    sym->st_value = addr;
                    goto found;
                }
            } else if (dynsym) {
                /* if dynamic symbol exist, then use it */
                sym_index = find_elf_sym(dynsym, name);
                if (sym_index) {
                    esym = &((Elf32_Sym *)dynsym->data)[sym_index];
                    sym->st_value = esym->st_value;
                    goto found;
                }
            }
            /* XXX: _fp_hw seems to be part of the ABI, so we ignore
               it */
            if (!strcmp(name, "_fp_hw"))
                goto found;
            /* only weak symbols are accepted to be undefined. Their
               value is zero */
            sym_bind = ELF32_ST_BIND(sym->st_info);
            if (sym_bind == STB_WEAK) {
                sym->st_value = 0;
            } else {
                error("undefined symbol '%s'", name);
            }
        } else if (sh_num < SHN_LORESERVE) {
            /* add section base */
            sym->st_value += sections[sym->st_shndx]->sh_addr;
        }
    found: ;
    }
}

/* elf relocation, CPU dependant */
static void elf_reloc(unsigned char *ptr, 
                      unsigned long addr, unsigned long val, int type, 
                      int sym_index)
{
    switch(type) {
    case R_386_32:
        *(int *)ptr += val;
        break;
    case R_386_PLT32:
    case R_386_PC32:
        *(int *)ptr += val - addr;
        break;
    case R_386_GLOB_DAT:
    case R_386_JMP_SLOT:
        *(int *)ptr = val;
        break;
    case R_386_GOTPC:
        *(int *)ptr += got->sh_addr - addr;
        break;
    case R_386_GOTOFF:
        *(int *)ptr += val - got->sh_addr;
        break;
    case R_386_GOT32:
        /* we load the got offset */
        *(int *)ptr += got_offsets[sym_index];
        break;
    }
}


/* relocate a given section */
static void relocate_section(Section *s)
{
    Section *sr;
    Elf32_Rel *rel, *rel_end;
    Elf32_Sym *sym;
    int type, sym_index;
    unsigned char *ptr;
    unsigned long val;

    sr = s->reloc;
    rel_end = (Elf32_Rel *)(sr->data + sr->data_offset);
    for(rel = (Elf32_Rel *)sr->data;
        rel < rel_end;
        rel++) {
        ptr = s->data + rel->r_offset;

        sym_index = ELF32_R_SYM(rel->r_info);
        sym = &((Elf32_Sym *)symtab_section->data)[sym_index];
        val = sym->st_value;
        type = ELF32_R_TYPE(rel->r_info);
        elf_reloc(ptr, s->sh_addr + rel->r_offset, val, type, sym_index);
    }
}

/* relocate relocation table in 'sr' */
static void relocate_rel(Section *sr)
{
    Section *s;
    Elf32_Rel *rel, *rel_end;
    
    s = sections[sr->sh_info];
    rel_end = (Elf32_Rel *)(sr->data + sr->data_offset);
    for(rel = (Elf32_Rel *)sr->data;
        rel < rel_end;
        rel++) {
        rel->r_offset += s->sh_addr;
    }
}

static void put_got_offset(int index, unsigned long val)
{
    int n;
    unsigned long *tab;

    if (index >= nb_got_offsets) {
        /* find immediately bigger power of 2 and reallocate array */
        n = 1;
        while (index >= n)
            n *= 2;
        tab = realloc(got_offsets, n * sizeof(unsigned long));
        if (!tab)
            error("memory full");
        got_offsets = tab;
        memset(got_offsets + nb_got_offsets, 0,
               (n - nb_got_offsets) * sizeof(unsigned long));
        nb_got_offsets = n;
    }
    got_offsets[index] = val;
}

/* XXX: suppress that */
static void put32(unsigned char *p, unsigned int val)
{
    p[0] = val;
    p[1] = val >> 8;
    p[2] = val >> 16;
    p[3] = val >> 24;
}

static void build_got(void)
{
    unsigned char *ptr;

    /* if no got, then create it */
    got = new_section(".got", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
    got->sh_entsize = 4;
    add_elf_sym(symtab_section, 0, 4, ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT), 
                got->sh_num, "_GLOBAL_OFFSET_TABLE_");
    ptr = section_ptr_add(got, 3 * sizeof(int));
    /* keep space for _DYNAMIC pointer, if present */
    put32(ptr, 0);
    /* two dummy got entries */
    put32(ptr + 4, 0);
    put32(ptr + 8, 0);
}

/* put a got entry corresponding to a symbol in symtab_section. 'size'
   and 'info' can be modifed if more precise info comes from the DLL */
static void put_got_entry(int reloc_type, unsigned long size, int info, 
                          int sym_index)
{
    int index;
    const char *name;
    Elf32_Sym *sym;
    unsigned long offset;
    int *ptr;

    if (!got)
        build_got();

    /* if a got entry already exists for that symbol, no need to add one */
    if (sym_index < nb_got_offsets &&
        got_offsets[sym_index] != 0)
        return;
    
    put_got_offset(sym_index, got->data_offset);

    if (dynsym) {
        sym = &((Elf32_Sym *)symtab_section->data)[sym_index];
        name = symtab_section->link->data + sym->st_name;
        offset = sym->st_value;
        /* NOTE: we put temporarily the got offset */
        if (reloc_type == R_386_JMP_SLOT) {
            nb_plt_entries++;
            offset = got->data_offset;
        }
        index = put_elf_sym(dynsym, offset, 
                            size, info, 0, sym->st_shndx, name);
        /* put a got entry */
        put_elf_reloc(dynsym, got, 
                      got->data_offset, 
                      reloc_type, index);
    }
    ptr = section_ptr_add(got, sizeof(int));
    *ptr = 0;
}

/* build GOT and PLT entries */
static void build_got_entries(void)
{
    Section *s, *symtab;
    Elf32_Rel *rel, *rel_end;
    Elf32_Sym *sym;
    int i, type, reloc_type, sym_index;

    for(i = 1; i < nb_sections; i++) {
        s = sections[i];
        if (s->sh_type != SHT_REL)
            continue;
        /* no need to handle got relocations */
        if (s->link != symtab_section)
            continue;
        symtab = s->link;
        rel_end = (Elf32_Rel *)(s->data + s->data_offset);
        for(rel = (Elf32_Rel *)s->data;
            rel < rel_end;
            rel++) {
            type = ELF32_R_TYPE(rel->r_info);
            switch(type) {
            case R_386_GOT32:
            case R_386_GOTOFF:
            case R_386_GOTPC:
            case R_386_PLT32:
                if (!got)
                    build_got();
                if (type == R_386_GOT32 || type == R_386_PLT32) {
                    sym_index = ELF32_R_SYM(rel->r_info);
                    sym = &((Elf32_Sym *)symtab_section->data)[sym_index];
                    /* look at the symbol got offset. If none, then add one */
                    if (type == R_386_GOT32)
                        reloc_type = R_386_GLOB_DAT;
                    else
                        reloc_type = R_386_JMP_SLOT;
                    put_got_entry(reloc_type, sym->st_size, sym->st_info, 
                                  sym_index);
                }
                break;
            default:
                break;
            }
        }
    }
}

static Section *new_section_hash(const char *name, int sh_flags, 
                                 int nb_buckets, Section *symtab)
{
    Section *hash;
    hash = new_section(name, SHT_HASH, sh_flags);
    ((int *)hash->data)[0] = nb_buckets;
    ((int *)hash->data)[1] = 1;
    hash->sh_entsize = sizeof(int);
    section_ptr_add(hash, (2 + nb_buckets + 1) * sizeof(int));
    symtab->hash = hash;
    hash->link = symtab;
    return hash;
}

/* put dynamic tag */
static void put_dt(Section *dynamic, int dt, unsigned long val)
{
    Elf32_Dyn *dyn;
    dyn = section_ptr_add(dynamic, sizeof(Elf32_Dyn));
    dyn->d_tag = dt;
    dyn->d_un.d_val = val;
}

/* add tcc runtime libraries */
static void tcc_add_runtime(TCCState *s1)
{
    char buf[1024];
    unsigned long *ptr;

    snprintf(buf, sizeof(buf), "%s/%s", tcc_lib_path, "libtcc1.o");
    tcc_add_file(s1, buf);
#ifdef CONFIG_TCC_BCHECK
    if (do_bounds_check) {
        /* XXX: add an object file to do that */
        ptr = section_ptr_add(bounds_section, sizeof(unsigned long));
        *ptr = 0;
        add_elf_sym(symtab_section, 0, 0, 
                    ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE),
                    bounds_section->sh_num, "__bounds_start");
        add_elf_sym(symtab_section, (long)&rt_error, 0, 
                    ELF32_ST_INFO(STB_GLOBAL, STT_FUNC),
                    SHN_ABS, "rt_error");
        /* add bound check code */
        snprintf(buf, sizeof(buf), "%s/%s", tcc_lib_path, "bcheck.o");
        tcc_add_file(s1, buf);
    }
#endif
    /* add libc if not memory output */
    if (s1->output_type != TCC_OUTPUT_MEMORY) {
        tcc_add_library(s1, "c");
        tcc_add_file(s1, CONFIG_TCC_CRT_PREFIX "/crtn.o");
    }
    /* add various standard linker symbols */
    add_elf_sym(symtab_section, 
                text_section->data_offset, 0,
                ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE),
                text_section->sh_num, "_etext");
    add_elf_sym(symtab_section, 
                data_section->data_offset, 0,
                ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE),
                data_section->sh_num, "_edata");
    add_elf_sym(symtab_section, 
                bss_section->data_offset, 0,
                ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE),
                bss_section->sh_num, "_end");
}

/* add dynamic sections so that the executable is dynamically linked */
static char elf_interp[] = "/lib/ld-linux.so.2";

#define ELF_START_ADDR 0x08048000
#define ELF_PAGE_SIZE  0x1000

/* output an ELF file */
/* XXX: handle realloc'ed sections (instead of mmaping them) */
/* XXX: suppress unneeded sections */
int tcc_output_file(TCCState *s1, const char *filename)
{
    Elf32_Ehdr ehdr;
    FILE *f;
    int fd, mode;
    int *section_order;
    int shnum, i, phnum, file_offset, offset, size, j, tmp, sh_order_index, k;
    unsigned long addr;
    Section *strsec, *s;
    Elf32_Shdr shdr, *sh;
    Elf32_Phdr *phdr, *ph;
    Section *interp, *plt, *dynamic, *dynstr, *hash;
    unsigned long saved_dynamic_data_offset;
    Elf32_Sym *sym;
    int type, file_type;
    unsigned long rel_addr, rel_size;
    
    file_type = s1->output_type;

    if (file_type != TCC_OUTPUT_OBJ)
        tcc_add_runtime(s1);

    interp = NULL;
    dynamic = NULL;
    dynsym = NULL;
    got = NULL;
    nb_plt_entries = 0;
    plt = NULL; /* avoid warning */
    hash = NULL; /* avoid warning */
    dynstr = NULL; /* avoid warning */
    saved_dynamic_data_offset = 0; /* avoid warning */

    if (file_type != TCC_OUTPUT_OBJ) {

        relocate_common_syms();

        if (!static_link) {
            const char *name;
            int sym_index, index;
            Elf32_Sym *esym, *sym_end;
            
            if (file_type == TCC_OUTPUT_EXE) {
                char *ptr;
                /* add interpreter section only if executable */
                interp = new_section(".interp", SHT_PROGBITS, SHF_ALLOC);
                interp->sh_addralign = 1;
                ptr = section_ptr_add(interp, sizeof(elf_interp));
                strcpy(ptr, elf_interp);
            }
        
            /* add dynamic symbol table */
            dynsym = new_section(".dynsym", SHT_DYNSYM, SHF_ALLOC);
            dynsym->sh_entsize = sizeof(Elf32_Sym);
            dynstr = new_section(".dynstr", SHT_STRTAB, SHF_ALLOC);
            put_elf_str(dynstr, "");
            dynsym->link = dynstr;
            put_elf_sym(dynsym, 0, 0, 0, 0, 0, NULL);
        
            /* hash table */
            hash = new_section_hash(".hash", SHF_ALLOC, 
                                    ELF_DYNSYM_HASH_SIZE, dynsym);

            /* add dynamic section */
            dynamic = new_section(".dynamic", SHT_DYNAMIC, 
                                  SHF_ALLOC | SHF_WRITE);
            dynamic->link = dynstr;
            dynamic->sh_entsize = sizeof(Elf32_Dyn);
        
            /* add PLT */
            plt = new_section(".plt", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR);
            plt->sh_entsize = 4;

            /* scan for undefined symbols and see if they are in the
               dynamic symbols. If a symbol STT_FUNC is found, then we
               add it in the PLT. If a symbol STT_OBJECT is found, we
               add it in the .bss section with a suitable relocation */
            sym_end = (Elf32_Sym *)(symtab_section->data + 
                                    symtab_section->data_offset);
            for(sym = (Elf32_Sym *)symtab_section->data + 1; 
                sym < sym_end;
                sym++) {
                if (sym->st_shndx == SHN_UNDEF) {
                    name = symtab_section->link->data + sym->st_name;
                    sym_index = find_elf_sym(dynsymtab_section, name);
                    if (sym_index) {
                        esym = &((Elf32_Sym *)dynsymtab_section->data)[sym_index];
                        type = ELF32_ST_TYPE(esym->st_info);
                        if (type == STT_FUNC) {
                            put_got_entry(R_386_JMP_SLOT, esym->st_size, 
                                          esym->st_info, 
                                          sym - (Elf32_Sym *)symtab_section->data);
                        } else if (type == STT_OBJECT) {
                            unsigned long offset;
                            offset = bss_section->data_offset;
                            /* XXX: which alignment ? */
                            offset = (offset + 8 - 1) & -8;
                            index = put_elf_sym(dynsym, offset, esym->st_size, 
                                                esym->st_info, 0, 
                                                bss_section->sh_num, name);
                            put_elf_reloc(dynsym, bss_section, 
                                          offset, R_386_COPY, index);
                            offset += esym->st_size;
                            bss_section->data_offset = offset;
                        }
                    } else {
                        /* STT_NOTYPE or STB_WEAK undefined symbols
                           are accepted */
                        /* XXX: STT_NOTYPE is only used to exclude the
                           unreferenced '_fp_hw' symbol. need a better
                           solution */
                        if (ELF32_ST_TYPE(sym->st_info) == STT_NOTYPE ||
                            ELF32_ST_BIND(sym->st_info) == STB_WEAK) {
                        } else {
                            error("undefined symbol '%s'", name);
                        }
                    }
                }
            }
            
            /* now look at unresolved dynamic symbols and export
               corresponding symbol */
            sym_end = (Elf32_Sym *)(dynsymtab_section->data + 
                                    dynsymtab_section->data_offset);
            for(sym = (Elf32_Sym *)dynsymtab_section->data + 1; 
                sym < sym_end;
                sym++) {
                if (sym->st_shndx == SHN_UNDEF) {
                    name = dynsymtab_section->link->data + sym->st_name;
                    sym_index = find_elf_sym(symtab_section, name);
                    if (sym_index) {
                    } else {
                        if (ELF32_ST_BIND(sym->st_info) == STB_WEAK) {
                            /* weak symbols can stay undefined */
                        } else {
                            warning("undefined dynamic symbol '%s'", name);
                        }
                    }
                }
            }
        
            build_got_entries();
        
            /* update PLT/GOT sizes so that we can allocate their space */
            plt->data_offset += 16 * (nb_plt_entries + 1);

            /* add a list of needed dlls */
            for(i = 0; i < nb_loaded_dlls; i++) {
                DLLReference *dllref = loaded_dlls[i];
                if (dllref->level == 0)
                    put_dt(dynamic, DT_NEEDED, put_elf_str(dynstr, dllref->name));
            }

            /* add necessary space for other entries */
            saved_dynamic_data_offset = dynamic->data_offset;
            dynamic->data_offset += 8 * 9;
        } else {
            /* still need to build got entries in case of static link */
            build_got_entries();
        }
    }

    memset(&ehdr, 0, sizeof(ehdr));

    /* we add a section for symbols */
    strsec = new_section(".shstrtab", SHT_STRTAB, 0);
    put_elf_str(strsec, "");
    
    /* compute number of sections */
    shnum = nb_sections;

    /* this array is used to reorder sections in the output file */
    section_order = malloc(sizeof(int) * shnum);
    if (!section_order)
        error("memory full");
    section_order[0] = 0;
    sh_order_index = 1;
    
    /* compute number of program headers */
    switch(file_type) {
    default:
    case TCC_OUTPUT_OBJ:
        phnum = 0;
        break;
    case TCC_OUTPUT_EXE:
        if (!static_link)
            phnum = 4;
        else
            phnum = 2;
        break;
    case TCC_OUTPUT_DLL:
        phnum = 3;
        break;
    }

    /* allocate strings for section names */
    for(i = 1; i < nb_sections; i++) {
        s = sections[i];
        s->sh_name = put_elf_str(strsec, s->name);
        s->sh_size = s->data_offset;
    }

    /* allocate program segment headers */
    phdr = malloc(phnum * sizeof(Elf32_Phdr));
    if (!phdr)
        error("memory full");
    memset(phdr, 0, phnum * sizeof(Elf32_Phdr));
        
    file_offset = sizeof(Elf32_Ehdr) + phnum * sizeof(Elf32_Phdr);
    if (phnum > 0) {
        /* compute section to program header mapping */
        if (file_type == TCC_OUTPUT_DLL)
            addr = 0;
        else
            addr = ELF_START_ADDR;

        /* dynamic relocation table information, for .dynamic section */
        rel_size = 0;
        rel_addr = 0;

        /* compute address after headers */
        addr += (file_offset & (ELF_PAGE_SIZE - 1));
        
        /* leave one program header for the program interpreter */
        ph = &phdr[0];
        if (interp)
            ph++;

        for(j = 0; j < 2; j++) {
            ph->p_type = PT_LOAD;
            if (j == 0)
                ph->p_flags = PF_R | PF_X;
            else
                ph->p_flags = PF_R | PF_W;
            ph->p_align = ELF_PAGE_SIZE;
            
            /* we do the following ordering: interp, symbol tables,
               relocations, progbits, nobits */
            /* XXX: do faster and simpler sorting */
            for(k = 0; k < 5; k++) {
                for(i = 1; i < nb_sections; i++) {
                    s = sections[i];
                    /* compute if section should be included */
                    if (j == 0) {
                        if ((s->sh_flags & (SHF_ALLOC | SHF_WRITE)) != 
                            SHF_ALLOC)
                            continue;
                    } else {
                        if ((s->sh_flags & (SHF_ALLOC | SHF_WRITE)) != 
                            (SHF_ALLOC | SHF_WRITE))
                            continue;
                    }
                    if (s == interp) {
                        if (k != 0)
                            continue;
                    } else if (s->sh_type == SHT_DYNSYM ||
                               s->sh_type == SHT_STRTAB ||
                               s->sh_type == SHT_HASH) {
                        if (k != 1)
                            continue;
                    } else if (s->sh_type == SHT_REL) {
                        if (k != 2)
                            continue;
                    } else if (s->sh_type == SHT_NOBITS) {
                        if (k != 4)
                            continue;
                    } else {
                        if (k != 3)
                            continue;
                    }
                    section_order[sh_order_index++] = i;

                    /* section matches: we align it and add its size */
                    tmp = file_offset;
                    file_offset = (file_offset + s->sh_addralign - 1) & 
                        ~(s->sh_addralign - 1);
                    s->sh_offset = file_offset;
                    addr += file_offset - tmp;
                    s->sh_addr = addr;
                    
                    /* update program header infos */
                    if (ph->p_offset == 0) {
                        ph->p_offset = file_offset;
                        ph->p_vaddr = addr;
                        ph->p_paddr = ph->p_vaddr;
                    }
                    /* update dynamic relocation infos */
                    if (s->sh_type == SHT_REL) {
                        if (rel_size == 0)
                            rel_addr = addr;
                        rel_size += s->sh_size;
                    }
                    addr += s->sh_size;
                    if (s->sh_type != SHT_NOBITS)
                        file_offset += s->sh_size;
                }
            }
            ph->p_filesz = file_offset - ph->p_offset;
            ph->p_memsz = addr - ph->p_vaddr;
            ph++;
        }

        /* if interpreter, then add corresponing program header */
        if (interp) {
            ph = &phdr[0];
            
            ph->p_type = PT_INTERP;
            ph->p_offset = interp->sh_offset;
            ph->p_vaddr = interp->sh_addr;
            ph->p_paddr = ph->p_vaddr;
            ph->p_filesz = interp->sh_size;
            ph->p_memsz = interp->sh_size;
            ph->p_flags = PF_R;
            ph->p_align = interp->sh_addralign;
        }
        
        /* if dynamic section, then add corresponing program header */
        if (dynamic) {
            int plt_offset;
            unsigned char *p;
            Elf32_Sym *sym_end;

            ph = &phdr[phnum - 1];
            
            ph->p_type = PT_DYNAMIC;
            ph->p_offset = dynamic->sh_offset;
            ph->p_vaddr = dynamic->sh_addr;
            ph->p_paddr = ph->p_vaddr;
            ph->p_filesz = dynamic->sh_size;
            ph->p_memsz = dynamic->sh_size;
            ph->p_flags = PF_R | PF_W;
            ph->p_align = dynamic->sh_addralign;

            /* put GOT dynamic section address */
            put32(got->data, dynamic->sh_addr);

            /* compute the PLT */
            plt->data_offset = 0;
            
            /* first plt entry */
            p = section_ptr_add(plt, 16);
            p[0] = 0xff; /* pushl got + 4 */
            p[1] = 0x35;
            put32(p + 2, got->sh_addr + 4);
            p[6] = 0xff; /* jmp *(got + 8) */
            p[7] = 0x25;
            put32(p + 8, got->sh_addr + 8);
            
            /* relocation symbols in .dynsym and build PLT. */
            plt_offset = 0;
            sym_end = (Elf32_Sym *)(dynsym->data + dynsym->data_offset);
            for(sym = (Elf32_Sym *)dynsym->data + 1; 
                sym < sym_end;
                sym++) {
                type = ELF32_ST_TYPE(sym->st_info);
                if (sym->st_shndx == SHN_UNDEF) {
                    if (type == STT_FUNC) {
                        /* one more entry in PLT */
                        p = section_ptr_add(plt, 16);
                        p[0] = 0xff; /* jmp *(got + x) */
                        p[1] = 0x25;
                        put32(p + 2, got->sh_addr + sym->st_value);
                        p[6] = 0x68; /* push $xxx */
                        put32(p + 7, plt_offset);
                        p[11] = 0xe9; /* jmp plt_start */
                        put32(p + 12, -(plt->data_offset));
                        
                        /* patch symbol value to point to plt */
                        sym->st_value = plt->sh_addr + p - plt->data;
                        
                        plt_offset += 8;
                    }
                } else if (sym->st_shndx < SHN_LORESERVE) {
                    /* do symbol relocation */
                    sym->st_value += sections[sym->st_shndx]->sh_addr;
                }
            }
            /* put dynamic section entries */

            dynamic->data_offset = saved_dynamic_data_offset;
            put_dt(dynamic, DT_HASH, hash->sh_addr);
            put_dt(dynamic, DT_STRTAB, dynstr->sh_addr);
            put_dt(dynamic, DT_SYMTAB, dynsym->sh_addr);
            put_dt(dynamic, DT_STRSZ, dynstr->data_offset);
            put_dt(dynamic, DT_SYMENT, sizeof(Elf32_Sym));
            put_dt(dynamic, DT_REL, rel_addr);
            put_dt(dynamic, DT_RELSZ, rel_size);
            put_dt(dynamic, DT_RELENT, sizeof(Elf32_Rel));
            put_dt(dynamic, DT_NULL, 0);
        }

        ehdr.e_phentsize = sizeof(Elf32_Phdr);
        ehdr.e_phnum = phnum;
        ehdr.e_phoff = sizeof(Elf32_Ehdr);
    }

    /* all other sections come after */
    for(i = 1; i < nb_sections; i++) {
        s = sections[i];
        if (phnum > 0 && (s->sh_flags & SHF_ALLOC))
            continue;
        section_order[sh_order_index++] = i;
        
        file_offset = (file_offset + s->sh_addralign - 1) & 
            ~(s->sh_addralign - 1);
        s->sh_offset = file_offset;
        if (s->sh_type != SHT_NOBITS)
            file_offset += s->sh_size;
    }
    
    /* if building executable or DLL, then relocate each section
       except the GOT which is already relocated */
    if (file_type != TCC_OUTPUT_OBJ) {
        relocate_syms(0);

        /* relocate sections */
        /* XXX: ignore sections with allocated relocations ? */
        for(i = 1; i < nb_sections; i++) {
            s = sections[i];
            if (s->reloc && s != got)
                relocate_section(s);
        }

        /* relocate relocation entries if the relocation tables are
           allocated in the executable */
        for(i = 1; i < nb_sections; i++) {
            s = sections[i];
            if ((s->sh_flags & SHF_ALLOC) &&
                s->sh_type == SHT_REL) {
                relocate_rel(s);
            }
        }

        /* get entry point address */
        ehdr.e_entry = get_elf_sym_val("_start");
    }

    sort_syms(symtab_section);

    /* align to 4 */
    file_offset = (file_offset + 3) & -4;
    
    /* fill header */
    ehdr.e_ident[0] = ELFMAG0;
    ehdr.e_ident[1] = ELFMAG1;
    ehdr.e_ident[2] = ELFMAG2;
    ehdr.e_ident[3] = ELFMAG3;
    ehdr.e_ident[4] = ELFCLASS32;
    ehdr.e_ident[5] = ELFDATA2LSB;
    ehdr.e_ident[6] = EV_CURRENT;
    switch(file_type) {
    default:
    case TCC_OUTPUT_EXE:
        ehdr.e_type = ET_EXEC;
        break;
    case TCC_OUTPUT_DLL:
        ehdr.e_type = ET_DYN;
        break;
    case TCC_OUTPUT_OBJ:
        ehdr.e_type = ET_REL;
        break;
    }
    ehdr.e_machine = EM_386;
    ehdr.e_version = EV_CURRENT;
    ehdr.e_shoff = file_offset;
    ehdr.e_ehsize = sizeof(Elf32_Ehdr);
    ehdr.e_shentsize = sizeof(Elf32_Shdr);
    ehdr.e_shnum = shnum;
    ehdr.e_shstrndx = shnum - 1;
    
    /* write elf file */
    if (file_type == TCC_OUTPUT_OBJ)
        mode = 0666;
    else
        mode = 0777;
    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, mode); 
    if (fd < 0)
        error("could not write '%s'", filename);

    f = fdopen(fd, "w");
    fwrite(&ehdr, 1, sizeof(Elf32_Ehdr), f);
    fwrite(phdr, 1, phnum * sizeof(Elf32_Phdr), f);
    offset = sizeof(Elf32_Ehdr) + phnum * sizeof(Elf32_Phdr);
    for(i=1;i<nb_sections;i++) {
        s = sections[section_order[i]];
        if (s->sh_type != SHT_NOBITS) {
            while (offset < s->sh_offset) {
                fputc(0, f);
                offset++;
            }
            size = s->data_offset;
            fwrite(s->data, 1, size, f);
            offset += size;
        }
    }
    while (offset < ehdr.e_shoff) {
        fputc(0, f);
        offset++;
    }
    
    /* output section headers */
    for(i=0;i<nb_sections;i++) {
        sh = &shdr;
        memset(sh, 0, sizeof(Elf32_Shdr));
        s = sections[i];
        if (s) {
            sh->sh_name = s->sh_name;
            sh->sh_type = s->sh_type;
            sh->sh_flags = s->sh_flags;
            sh->sh_entsize = s->sh_entsize;
            sh->sh_info = s->sh_info;
            if (s->link)
                sh->sh_link = s->link->sh_num;
            sh->sh_addralign = s->sh_addralign;
            sh->sh_addr = s->sh_addr;
            sh->sh_offset = s->sh_offset;
            sh->sh_size = s->sh_size;
        }
        fwrite(sh, 1, sizeof(Elf32_Shdr), f);
    }
    fclose(f);

    free(section_order);
    free(phdr);
    return 0;
}

static void *load_data(int fd, unsigned long file_offset, unsigned long size)
{
    void *data;

    data = malloc(size);
    if (!data)
        error("memory full");
    lseek(fd, file_offset, SEEK_SET);
    read(fd, data, size);
    return data;
}

typedef struct SectionMergeInfo {
    Section *s;            /* corresponding existing section */
    unsigned long offset;  /* offset of the new section in the existing section */
    int new_section;       /* true if section 's' was added */
} SectionMergeInfo;

/* load an object file and merge it with current files */
/* XXX: handle correctly stab (debug) info */
static int tcc_load_object_file(TCCState *s1, 
                                int fd, unsigned long file_offset)
{ 
    Elf32_Ehdr ehdr;
    Elf32_Shdr *shdr, *sh;
    int size, i, j, offset, offseti, nb_syms, sym_index;
    unsigned char *strsec, *strtab;
    int *old_to_new_syms;
    char *sh_name, *name;
    SectionMergeInfo *sm_table, *sm;
    Elf32_Sym *sym, *symtab;
    Elf32_Rel *rel, *rel_end;
    Section *s;

    if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
        goto fail;
    if (ehdr.e_ident[0] != ELFMAG0 ||
        ehdr.e_ident[1] != ELFMAG1 ||
        ehdr.e_ident[2] != ELFMAG2 ||
        ehdr.e_ident[3] != ELFMAG3)
        goto fail;
    /* test if object file */
    if (ehdr.e_type != ET_REL)
        goto fail;
    /* test CPU specific stuff */
    if (ehdr.e_ident[5] != ELFDATA2LSB ||
        ehdr.e_machine != EM_386) {
    fail:
        error("invalid object file");
    }
    /* read sections */
    shdr = load_data(fd, file_offset + ehdr.e_shoff, 
                     sizeof(Elf32_Shdr) * ehdr.e_shnum);
    sm_table = malloc(sizeof(SectionMergeInfo) * ehdr.e_shnum);
    if (!sm_table)
        error("memory full");
    memset(sm_table, 0, sizeof(SectionMergeInfo) * ehdr.e_shnum);
    
    /* load section names */
    sh = &shdr[ehdr.e_shstrndx];
    strsec = load_data(fd, file_offset + sh->sh_offset, sh->sh_size);

    /* load symtab and strtab */
    symtab = NULL;
    strtab = NULL;
    nb_syms = 0;
    for(i = 1; i < ehdr.e_shnum; i++) {
        sh = &shdr[i];
        if (sh->sh_type == SHT_SYMTAB) {
            if (symtab)
                error("object must contain only one symtab");
            nb_syms = sh->sh_size / sizeof(Elf32_Sym);
            symtab = load_data(fd, file_offset + sh->sh_offset, sh->sh_size);
            sm_table[i].s = symtab_section;

            /* now load strtab */
            sh = &shdr[sh->sh_link];
            strtab = load_data(fd, file_offset + sh->sh_offset, sh->sh_size);
        }
    }
        
    /* now examine each section and try to merge its content with the
       ones in memory */
    for(i = 1; i < ehdr.e_shnum; i++) {
        /* no need to examine section name strtab */
        if (i == ehdr.e_shstrndx)
            continue;
        sh = &shdr[i];
        sh_name = strsec + sh->sh_name;
        /* ignore sections types we do not handle */
        if (sh->sh_type != SHT_PROGBITS &&
            sh->sh_type != SHT_REL && 
            sh->sh_type != SHT_NOBITS)
            continue;
        if (sh->sh_addralign < 1)
            sh->sh_addralign = 1;
        /* find corresponding section, if any */
        for(j = 1; j < nb_sections;j++) {
            s = sections[j];
            if (!strcmp(s->name, sh_name))
                goto found;
        }
        /* not found: create new section */
        s = new_section(sh_name, sh->sh_type, sh->sh_flags);
        /* take as much info as possible from the section. sh_link and
           sh_info will be updated later */
        s->sh_addralign = sh->sh_addralign;
        s->sh_entsize = sh->sh_entsize;
        sm_table[i].new_section = 1;
    found:
        if (sh->sh_type != s->sh_type)
            goto fail;

        /* align start of section */
        offset = s->data_offset;
        size = sh->sh_addralign - 1;
        offset = (offset + size) & ~size;
        if (sh->sh_addralign > s->sh_addralign)
            s->sh_addralign = sh->sh_addralign;
        s->data_offset = offset;
        sm_table[i].offset = offset;
        sm_table[i].s = s;
        /* concatenate sections */
        size = sh->sh_size;
        if (sh->sh_type != SHT_NOBITS) {
            unsigned char *ptr;
            lseek(fd, file_offset + sh->sh_offset, SEEK_SET);
            ptr = section_ptr(s, size);
            read(fd, ptr, size);
        }
        s->data_offset += size;
    }

    /* second short pass to update sh_link and sh_info fields of new
       sections */
    sm = sm_table;
    for(i = 1; i < ehdr.e_shnum; i++) {
        s = sm_table[i].s;
        if (!s || !sm_table[i].new_section)
            continue;
        sh = &shdr[i];
        if (sh->sh_link > 0)
            s->link = sm_table[sh->sh_link].s;
        if (sh->sh_type == SHT_REL) {
            s->sh_info = sm_table[sh->sh_info].s->sh_num;
            /* update backward link */
            sections[s->sh_info]->reloc = s;
        }
    }

    /* resolve symbols */
    old_to_new_syms = malloc(nb_syms * sizeof(int));
    if (!old_to_new_syms)
        error("memory full");
    memset(old_to_new_syms, 0, nb_syms * sizeof(int));
    sym = symtab + 1;
    for(i = 1; i < nb_syms; i++, sym++) {
        if (sym->st_shndx != SHN_UNDEF &&
            sym->st_shndx < SHN_LORESERVE) {
            sm = &sm_table[sym->st_shndx];
            /* if no corresponding section added, no need to add symbol */
            if (!sm->s)
                continue;
            /* convert section number */
            sym->st_shndx = sm->s->sh_num;
            /* offset value */
            sym->st_value += sm->offset;
        }
        /* add symbol */
        name = strtab + sym->st_name;
        sym_index = add_elf_sym(symtab_section, sym->st_value, sym->st_size, 
                                sym->st_info, sym->st_shndx, name);
        old_to_new_syms[i] = sym_index;
    }

    /* third pass to patch relocation entries */
    for(i = 1; i < ehdr.e_shnum; i++) {
        s = sm_table[i].s;
        if (!s)
            continue;
        sh = &shdr[i];
        offset = sm_table[i].offset;
        switch(s->sh_type) {
        case SHT_REL:
            /* take relocation offset information */
            offseti = sm_table[sh->sh_info].offset;
            rel_end = (Elf32_Rel *)(s->data + s->data_offset);
            for(rel = (Elf32_Rel *)(s->data + offset);
                rel < rel_end;
                rel++) {
                int type;
                unsigned sym_index;
                /* convert symbol index */
                type = ELF32_R_TYPE(rel->r_info);
                sym_index = ELF32_R_SYM(rel->r_info);
                /* NOTE: only one symtab assumed */
                if (sym_index >= nb_syms)
                    goto invalid_reloc;
                sym_index = old_to_new_syms[sym_index];
                if (!sym_index) {
                invalid_reloc:
                    error("Invalid relocation entry");
                }
                rel->r_info = ELF32_R_INFO(sym_index, type);
                /* offset the relocation offset */
                rel->r_offset += offseti;
            }
            break;
        default:
            break;
        }
    }
    free(symtab);
    free(strtab);
    free(old_to_new_syms);
    free(sm_table);
    free(shdr);
    return 0;
}

#define ARMAG  "!<arch>\012"    /* For COFF and a.out archives */

typedef struct ArchiveHeader {
    char ar_name[16];           /* name of this member */
    char ar_date[12];           /* file mtime */
    char ar_uid[6];             /* owner uid; printed as decimal */
    char ar_gid[6];             /* owner gid; printed as decimal */
    char ar_mode[8];            /* file mode, printed as octal   */
    char ar_size[10];           /* file size, printed as decimal */
    char ar_fmag[2];            /* should contain ARFMAG */
} ArchiveHeader;

/* load a '.a' file */
static int tcc_load_archive(TCCState *s1, int fd)
{
    ArchiveHeader hdr;
    char ar_size[11];
    char ar_name[17];
    char magic[8];
    int size, len, i;
    unsigned long file_offset;

    /* skip magic which was already checked */
    read(fd, magic, sizeof(magic));
    
    for(;;) {
        len = read(fd, &hdr, sizeof(hdr));
        if (len == 0)
            break;
        if (len != sizeof(hdr))
            error("invalid archive");
        memcpy(ar_size, hdr.ar_size, sizeof(hdr.ar_size));
        ar_size[sizeof(hdr.ar_size)] = '\0';
        size = strtol(ar_size, NULL, 0);
        memcpy(ar_name, hdr.ar_name, sizeof(hdr.ar_name));
        for(i = sizeof(hdr.ar_name) - 1; i >= 0; i--) {
            if (ar_name[i] != ' ')
                break;
        }
        ar_name[i + 1] = '\0';
        //        printf("name='%s' size=%d %s\n", ar_name, size, ar_size);
        file_offset = lseek(fd, 0, SEEK_CUR);
        if (!strcmp(ar_name, "/") ||
            !strcmp(ar_name, "//") ||
            !strcmp(ar_name, "__.SYMDEF") ||
            !strcmp(ar_name, "__.SYMDEF/") ||
            !strcmp(ar_name, "ARFILENAMES/")) {
            /* skip symbol table or archive names */
        } else {
            tcc_load_object_file(s1, fd, file_offset);
        }
        /* align to even */
        size = (size + 1) & ~1;
        lseek(fd, file_offset + size, SEEK_SET);
    }
    return 0;
}

/* load a DLL and all referenced DLLs. 'level = 0' means that the DLL
   is referenced by the user (so it should be added as DT_NEEDED in
   the generated ELF file) */
static int tcc_load_dll(TCCState *s1, int fd, const char *filename, int level)
{ 
    Elf32_Ehdr ehdr;
    Elf32_Shdr *shdr, *sh, *sh1;
    int i, nb_syms, nb_dts, sym_bind;
    Elf32_Sym *sym, *dynsym;
    Elf32_Dyn *dt, *dynamic;
    unsigned char *dynstr;
    const char *name, *soname, *p;
    DLLReference *dllref;
    
    read(fd, &ehdr, sizeof(ehdr));

    /* test CPU specific stuff */
    if (ehdr.e_ident[5] != ELFDATA2LSB ||
        ehdr.e_machine != EM_386)
        error("bad architecture");

    /* read sections */
    shdr = load_data(fd, ehdr.e_shoff, sizeof(Elf32_Shdr) * ehdr.e_shnum);

    /* load dynamic section and dynamic symbols */
    nb_syms = 0;
    nb_dts = 0;
    dynamic = NULL;
    dynsym = NULL; /* avoid warning */
    dynstr = NULL; /* avoid warning */
    for(i = 0, sh = shdr; i < ehdr.e_shnum; i++, sh++) {
        switch(sh->sh_type) {
        case SHT_DYNAMIC:
            nb_dts = sh->sh_size / sizeof(Elf32_Dyn);
            dynamic = load_data(fd, sh->sh_offset, sh->sh_size);
            break;
        case SHT_DYNSYM:
            nb_syms = sh->sh_size / sizeof(Elf32_Sym);
            dynsym = load_data(fd, sh->sh_offset, sh->sh_size);
            sh1 = &shdr[sh->sh_link];
            dynstr = load_data(fd, sh1->sh_offset, sh1->sh_size);
            break;
        default:
            break;
        }
    }
    
    /* compute the real library name */
    soname = filename;
    p = strrchr(soname, '/');
    if (p)
        soname = p + 1;
        
    for(i = 0, dt = dynamic; i < nb_dts; i++, dt++) {
        if (dt->d_tag == DT_SONAME) {
            soname = dynstr + dt->d_un.d_val;
        }
    }

    /* if the dll is already loaded, do not load it */
    for(i = 0; i < nb_loaded_dlls; i++) {
        dllref = loaded_dlls[i];
        if (!strcmp(soname, dllref->name)) {
            /* but update level if needed */
            if (level < dllref->level)
                dllref->level = level;
            goto the_end;
        }
    }
    
    //    printf("loading dll '%s'\n", soname);

    /* add the dll and its level */
    dllref = malloc(sizeof(DLLReference) + strlen(soname));
    dllref->level = level;
    strcpy(dllref->name, soname);
    dynarray_add((void ***)&loaded_dlls, &nb_loaded_dlls, dllref);

    /* add dynamic symbols in dynsym_section */
    for(i = 1, sym = dynsym + 1; i < nb_syms; i++, sym++) {
        sym_bind = ELF32_ST_BIND(sym->st_info);
        if (sym_bind == STB_LOCAL)
            continue;
        name = dynstr + sym->st_name;
        add_elf_sym(dynsymtab_section, sym->st_value, sym->st_size,
                    sym->st_info, sym->st_shndx, name);
    }

    /* load all referenced DLLs */
    for(i = 0, dt = dynamic; i < nb_dts; i++, dt++) {
        switch(dt->d_tag) {
        case DT_NEEDED:
            name = dynstr + dt->d_un.d_val;
            for(i = 0; i < nb_loaded_dlls; i++) {
                dllref = loaded_dlls[i];
                if (!strcmp(name, dllref->name))
                    goto already_loaded;
            }
            if (tcc_add_dll(s1, name, AFF_REFERENCED_DLL) < 0)
                error("referenced dll '%s' not found", name);
        already_loaded:
            break;
        }
    }
 the_end:
    free(shdr);
    return 0;
}

/* return -2 if error and CH_EOF if eof */
static void ld_skipspaces(void)
{
    while (ch == ' ' || ch == '\t' || ch == '\n')
        cinp();
}

static int ld_get_cmd(char *cmd, int cmd_size)
{
    char *q;

    ld_skipspaces();
    if (ch == CH_EOF)
        return -1;
    q = cmd;
    for(;;) {
        if (!((ch >= 'a' && ch <= 'z') ||
              (ch >= 'A' && ch <= 'Z') ||
              (ch >= '0' && ch <= '9') ||
              strchr("/.-_+=$:\\,~?*", ch)))
            break;
        if ((q - cmd) >= (cmd_size - 1))
            return -2;
        *q++ = ch;
        cinp();
    }
    *q = '\0';
    return 0;
}
                     
/* interpret a subset of GNU ldscripts to handle the dummy libc.so
   files */
static int tcc_load_ldscript(TCCState *s1)
{
    char cmd[64];
    char filename[1024];
    int ret;
    
    inp();
    cinp();
    for(;;) {
        ret = ld_get_cmd(cmd, sizeof(cmd));
        if (ret == CH_EOF)
            return 0;
        else if (ret < 0)
            return -1;
        //        printf("cmd='%s'\n", cmd);
        if (!strcmp(cmd, "INPUT") ||
            !strcmp(cmd, "GROUP")) {
            ld_skipspaces();
            if (ch != '(')
                expect("(");
            cinp();
            for(;;) {
                ld_get_cmd(filename, sizeof(filename));
                tcc_add_file(s1, filename);
                ld_skipspaces();
                if (ch == ',') {
                    cinp();
                } else if (ch == ')') {
                    cinp();
                    break;
                } else if (ch == CH_EOF) {
                    error("unexpected end of file");
                }
            }
        } else {
            return -1;
        }
    }
    return 0;
}

/* print the position in the source file of PC value 'pc' by reading
   the stabs debug information */
static void rt_printline(unsigned long wanted_pc)
{
    Stab_Sym *sym, *sym_end;
    char func_name[128];
    unsigned long func_addr, last_pc, pc;
    const char *incl_files[INCLUDE_STACK_SIZE];
    int incl_index, len, last_line_num, i;
    const char *str, *p;

    func_name[0] = '\0';
    func_addr = 0;
    incl_index = 0;
    last_pc = 0xffffffff;
    last_line_num = 1;
    sym = (Stab_Sym *)stab_section->data + 1;
    sym_end = (Stab_Sym *)(stab_section->data + stab_section->data_offset);
    while (sym < sym_end) {
        switch(sym->n_type) {
            /* function start or end */
        case N_FUN:
            if (sym->n_strx == 0) {
                func_name[0] = '\0';
                func_addr = 0;
            } else {
                str = stabstr_section->data + sym->n_strx;
                p = strchr(str, ':');
                if (!p) {
                    pstrcpy(func_name, sizeof(func_name), str);
                } else {
                    len = p - str;
                    if (len > sizeof(func_name) - 1)
                        len = sizeof(func_name) - 1;
                    memcpy(func_name, str, len);
                    func_name[len] = '\0';
                }
                func_addr = sym->n_value;
            }
            break;
            /* line number info */
        case N_SLINE:
            pc = sym->n_value + func_addr;
            if (wanted_pc >= last_pc && wanted_pc < pc)
                goto found;
            last_pc = pc;
            last_line_num = sym->n_desc;
            break;
            /* include files */
        case N_BINCL:
            str = stabstr_section->data + sym->n_strx;
        add_incl:
            if (incl_index < INCLUDE_STACK_SIZE) {
                incl_files[incl_index++] = str;
            }
            break;
        case N_EINCL:
            if (incl_index > 1)
                incl_index--;
            break;
        case N_SO:
            if (sym->n_strx == 0) {
                incl_index = 0; /* end of translation unit */
            } else {
                str = stabstr_section->data + sym->n_strx;
                /* do not add path */
                len = strlen(str);
                if (len > 0 && str[len - 1] != '/')
                    goto add_incl;
            }
            break;
        }
        sym++;
    }
    /* did not find line number info: */
    fprintf(stderr, "(no debug info, pc=0x%08lx): ", wanted_pc);
    return;
 found:
    for(i = 0; i < incl_index - 1; i++)
        fprintf(stderr, "In file included from %s\n", 
                incl_files[i]);
    if (incl_index > 0) {
        fprintf(stderr, "%s:%d: ", 
                incl_files[incl_index - 1], last_line_num);
    }
    if (func_name[0] != '\0') {
        fprintf(stderr, "in function '%s()': ", func_name);
    }
}

/* emit a run time error at position 'pc' */
void rt_error(unsigned long pc, const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);

    rt_printline(pc);
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    exit(255);
    va_end(ap);
}

#ifndef WIN32
/* signal handler for fatal errors */
static void sig_error(int signum, siginfo_t *siginf, void *puc)
{
    struct ucontext *uc = puc;
    unsigned long pc;

#ifdef __i386__
    pc = uc->uc_mcontext.gregs[14];
#else
#error please put the right sigcontext field    
#endif

    switch(signum) {
    case SIGFPE:
        switch(siginf->si_code) {
        case FPE_INTDIV:
        case FPE_FLTDIV:
            rt_error(pc, "division by zero");
            break;
        default:
            rt_error(pc, "floating point exception");
            break;
        }
        break;
    case SIGBUS:
    case SIGSEGV:
        rt_error(pc, "dereferencing invalid pointer");
        break;
    case SIGILL:
        rt_error(pc, "illegal instruction");
        break;
    case SIGABRT:
        rt_error(pc, "abort() called");
        break;
    default:
        rt_error(pc, "caught signal %d", signum);
        break;
    }
    exit(255);
}
#endif

/* launch the compiled program with the given arguments */
int tcc_run(TCCState *s1, int argc, char **argv)
{
    Section *s;
    int (*prog_main)(int, char **);
    void (*bound_init)(void);
    int i;

    tcc_add_runtime(s1);

    relocate_common_syms();

    /* compute relocation address : section are relocated in place */
    for(i = 1; i < nb_sections; i++) {
        s = sections[i];
        if (s->sh_flags & SHF_ALLOC)
            s->sh_addr = (unsigned long)s->data;
    }

    relocate_syms(1);

    /* relocate each section */
    for(i = 1; i < nb_sections; i++) {
        s = sections[i];
        if (s->reloc)
            relocate_section(s);
    }

    prog_main = (void *)get_elf_sym_val("main");
    
    if (do_debug) {
#ifdef WIN32
        error("debug mode currently not available for Windows");
#else        
        struct sigaction sigact;
        /* install TCC signal handlers to print debug info on fatal
           runtime errors */
        sigact.sa_flags = SA_SIGINFO | SA_ONESHOT;
        sigact.sa_sigaction = sig_error;
        sigemptyset(&sigact.sa_mask);
        sigaction(SIGFPE, &sigact, NULL);
        sigaction(SIGILL, &sigact, NULL);
        sigaction(SIGSEGV, &sigact, NULL);
        sigaction(SIGBUS, &sigact, NULL);
        sigaction(SIGABRT, &sigact, NULL);
#endif
    }

#ifdef CONFIG_TCC_BCHECK
    if (do_bounds_check) {
        /* XXX: use .init section so that it also work in binary ? */
        bound_init = (void *)get_elf_sym_val("__bound_init");
        bound_init();
    }
#endif
    return (*prog_main)(argc, argv);
}

TCCState *tcc_new(void)
{
    char *p, *r;
    TCCState *s;

    s = malloc(sizeof(TCCState));
    if (!s)
        return NULL;
    s->output_type = TCC_OUTPUT_MEMORY;
    
    /* default include paths */
    tcc_add_include_path(s, "/usr/include");
    tcc_add_include_path(s, CONFIG_TCC_PREFIX "/lib/tcc/include");
    tcc_add_include_path(s, "/usr/local/include");

    /* add all tokens */
    tok_ident = TOK_IDENT;
    p = tcc_keywords;
    while (*p) {
        r = p;
        while (*r++);
        tok_alloc(p, r - p - 1);
        p = r;
    }

    /* standard defines */
    tcc_define_symbol(s, "__STDC__", NULL);
#if defined(TCC_TARGET_I386)
    tcc_define_symbol(s, "__i386__", NULL);
#endif
    /* tiny C specific defines */
    tcc_define_symbol(s, "__TINYC__", NULL);
    
    /* default library paths */
    tcc_add_library_path(s, "/usr/local/lib");
    tcc_add_library_path(s, "/usr/lib");
    tcc_add_library_path(s, "/lib");

    /* no section zero */
    dynarray_add((void ***)&sections, &nb_sections, NULL);

    /* create standard sections */
    text_section = new_section(".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR);
    data_section = new_section(".data", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
    bss_section = new_section(".bss", SHT_NOBITS, SHF_ALLOC | SHF_WRITE);

    /* symbols are always generated for linking stage */
    symtab_section = new_section(".symtab", SHT_SYMTAB, 0);
    symtab_section->sh_entsize = sizeof(Elf32_Sym);
    strtab_section = new_section(".strtab", SHT_STRTAB, 0);
    put_elf_str(strtab_section, "");
    symtab_section->link = strtab_section;
    put_elf_sym(symtab_section, 0, 0, 0, 0, 0, NULL);
    new_section_hash(".hashtab", SHF_PRIVATE, 
                     ELF_SYM_HASH_SIZE, symtab_section);
    
    /* private symbol table for dynamic symbols */
    dynsymtab_section = new_section(".dynsymtab", SHT_SYMTAB, SHF_PRIVATE);
    dynsymtab_section->sh_entsize = sizeof(Elf32_Sym);
    dynstrtab_section = new_section(".dynstrtab", SHT_STRTAB, SHF_PRIVATE);
    put_elf_str(dynstrtab_section, "");
    dynsymtab_section->link = dynstrtab_section;
    put_elf_sym(dynsymtab_section, 0, 0, 0, 0, 0, NULL);
    new_section_hash(".dynhashtab", SHF_PRIVATE, 
                     ELF_SYM_HASH_SIZE, dynsymtab_section);
    return s;
}

void tcc_delete(TCCState *s)
{
    free(s);
}

int tcc_add_include_path(TCCState *s, const char *pathname)
{
    char *pathname1;
    
    pathname1 = strdup(pathname);
    if (!pathname1)
        return -1;
    dynarray_add((void ***)&include_paths, &nb_include_paths, pathname1);
    return 0;
}

static int tcc_add_file_internal(TCCState *s, const char *filename, int flags)
{
    const char *ext;
    Elf32_Ehdr ehdr;
    int fd;
    BufferedFile *saved_file;
    
    /* find source file type with extension */
    ext = strrchr(filename, '.');
    if (ext)
        ext++;

    /* open the file */
    saved_file = file;
    file = tcc_open(filename);
    if (!file) {
        if (flags & AFF_PRINT_ERROR) {
            error("file '%s' not found", filename);
        } else {
            file = saved_file;
            return -1;
        }
    }

    if (!ext || !strcmp(ext, "c")) {
        /* C file assumed */
        tcc_compile(s);
    } else {
        fd = file->fd;
        /* assume executable format: auto guess file type */
        if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
            error("could not read header");
        lseek(fd, 0, SEEK_SET);
        
        if (ehdr.e_ident[0] == ELFMAG0 &&
            ehdr.e_ident[1] == ELFMAG1 &&
            ehdr.e_ident[2] == ELFMAG2 &&
            ehdr.e_ident[3] == ELFMAG3) {
            file->line_num = 0; /* do not display line number if error */
            if (ehdr.e_type == ET_REL) {
                tcc_load_object_file(s, fd, 0);
            } else if (ehdr.e_type == ET_DYN) {
                tcc_load_dll(s, fd, filename, (flags & AFF_REFERENCED_DLL) != 0);
            } else {
                error("unrecognized ELF file");
            }
        } else if (memcmp((char *)&ehdr, ARMAG, 8) == 0) {
            file->line_num = 0; /* do not display line number if error */
            tcc_load_archive(s, fd);
        } else {
            /* as GNU ld, consider it is an ld script if not recognized */
            if (tcc_load_ldscript(s) < 0)
                error("unrecognized file type");
        }
    }
    tcc_close(file);
    file = saved_file;
    return 0;
}

void tcc_add_file(TCCState *s, const char *filename)
{
    tcc_add_file_internal(s, filename, AFF_PRINT_ERROR);
}

int tcc_add_library_path(TCCState *s, const char *pathname)
{
    char *pathname1;
    
    pathname1 = strdup(pathname);
    if (!pathname1)
        return -1;
    dynarray_add((void ***)&library_paths, &nb_library_paths, pathname1);
    return 0;
}

/* find and load a dll. Return non zero if not found */
/* XXX: add '-rpath' option support ? */
static int tcc_add_dll(TCCState *s, const char *filename, int flags)
{
    char buf[1024];
    int i;

    for(i = 0; i < nb_library_paths; i++) {
        snprintf(buf, sizeof(buf), "%s/%s", 
                 library_paths[i], filename);
        if (tcc_add_file_internal(s, buf, flags) == 0)
            return 0;
    }
    return -1;
}

/* the library name is the same as the argument of the '-l' option */
int tcc_add_library(TCCState *s, const char *libraryname)
{
    char buf[1024];
    int i;
    void *h;
    
    /* if we output to memory, then we simply we dlopen(). */
    if (s->output_type == TCC_OUTPUT_MEMORY) {
        /* Since the libc is already loaded, we don't need to load it again */
        if (!strcmp(libraryname, "c"))
            return 0;
        snprintf(buf, sizeof(buf), "lib%s.so", libraryname);
        h = dlopen(buf, RTLD_GLOBAL | RTLD_LAZY);
        if (!h)
            return -1;
        return 0;
    }
    
    /* first we look for the dynamic library if not static linking */
    if (!static_link) {
        snprintf(buf, sizeof(buf), "lib%s.so", libraryname);
        if (tcc_add_dll(s, buf, 0) == 0)
            return 0;
    }

    /* then we look for the static library */
    for(i = 0; i < nb_library_paths; i++) {
        snprintf(buf, sizeof(buf), "%s/lib%s.a", 
                 library_paths[i], libraryname);
        if (tcc_add_file_internal(s, buf, 0) == 0)
            return 0;
    }
    return -1;
}

int tcc_add_symbol(TCCState *s, const char *name, unsigned long val)
{
    add_elf_sym(symtab_section, val, 0, 
                ELF32_ST_INFO(STB_GLOBAL, STT_NOTYPE),
                SHN_ABS, name);
    return 0;
}

int tcc_set_output_type(TCCState *s, int output_type)
{
    s->output_type = output_type;

    /* add libc crt1/crti objects */
    if (output_type == TCC_OUTPUT_EXE || 
        output_type == TCC_OUTPUT_DLL) {
        if (output_type != TCC_OUTPUT_DLL)
            tcc_add_file(s, CONFIG_TCC_CRT_PREFIX "/crt1.o");
        tcc_add_file(s, CONFIG_TCC_CRT_PREFIX "/crti.o");
    }
    return 0;
}

#if !defined(LIBTCC)

void help(void)
{
    printf("tcc version 0.9.8 - Tiny C Compiler - Copyright (C) 2001, 2002 Fabrice Bellard\n" 
           "usage: tcc [-c] [-o outfile] [-Bdir] [-bench] [-Idir] [-Dsym[=val]] [-Usym]\n"
           "           [-g] [-b] [-Ldir] [-llib] [-shared] [-static]\n"
           "           [--] infile1 [infile2... --] [infile_args...]\n"
           "\n"
           "General options:\n"
           "  -c          compile only - generate an object file\n"
           "  -o outfile  set output filename\n"
           "  --          allows multiples input files if no -o option given. Also\n" 
           "              separate input files from runtime arguments\n"
           "  -Bdir       set tcc internal library path\n"
           "  -bench      output compilation statistics\n"
           "Preprocessor options:\n"
           "  -Idir       add include path 'dir'\n"
           "  -Dsym[=val] define 'sym' with value 'val'\n"
           "  -Usym       undefine 'sym'\n"
           "C compiler options:\n"
           "  -g          generate runtime debug info\n"
#ifdef CONFIG_TCC_BCHECK
           "  -b          compile with built-in memory and bounds checker (implies -g)\n"
#endif
           "Linker options:\n"
           "  -Ldir       add library path 'dir'\n"
           "  -llib       link with dynamic library 'lib'\n"
           "  -shared     generate a shared library (NOT WORKING YET)\n"
           "  -static     static linking\n"
           );
}

int main(int argc, char **argv)
{
    char *r, *outfile;
    int optind, output_type, multiple_files, i;
    TCCState *s;
    char **libraries;
    int nb_libraries;
    
    s = tcc_new();
    output_type = TCC_OUTPUT_MEMORY;

    optind = 1;
    outfile = NULL;
    multiple_files = 0;
    libraries = NULL;
    nb_libraries = 0;
    while (1) {
        if (optind >= argc) {
        show_help:
            help();
            return 1;
        }
        r = argv[optind];
        if (r[0] != '-')
            break;
        optind++;
        if (r[1] == '-') {
            /* '--' enables multiple files input */
            multiple_files = 1;
        } else if (r[1] == 'h' || r[1] == '?') {
            goto show_help;
        } else if (r[1] == 'I') {
            if (tcc_add_include_path(s, r + 2) < 0)
                error("too many include paths");
        } else if (r[1] == 'D') {
            char *sym, *value;
            sym = r + 2;
            value = strchr(sym, '=');
            if (value) {
                *value = '\0';
                value++;
            }
            tcc_define_symbol(s, sym, value);
        } else if (r[1] == 'U') {
            tcc_undefine_symbol(s, r + 2);
        } else if (r[1] == 'L') {
            tcc_add_library_path(s, r + 2);
        } else if (r[1] == 'B') {
            /* set tcc utilities path (mainly for tcc development) */
            tcc_lib_path = r + 2;
        } else if (r[1] == 'l') {
            dynarray_add((void ***)&libraries, &nb_libraries, r + 2);
        } else if (!strcmp(r + 1, "bench")) {
            do_bench = 1;
#ifdef CONFIG_TCC_BCHECK
        } else if (r[1] == 'b') {
            if (!do_bounds_check) {
                do_bounds_check = 1;
                /* define symbol */
                tcc_define_symbol(s, "__BOUNDS_CHECKING_ON", NULL);
                /* create bounds sections */
                bounds_section = new_section(".bounds", 
                                             SHT_PROGBITS, SHF_ALLOC);
                lbounds_section = new_section(".lbounds", 
                                              SHT_PROGBITS, SHF_ALLOC);
                /* debug is implied */
                goto debug_opt;
            }
#endif
        } else if (r[1] == 'g') {
#ifdef CONFIG_TCC_BCHECK
        debug_opt:
#endif
            if (!do_debug) {
                do_debug = 1;

                /* stab symbols */
                stab_section = new_section(".stab", SHT_PROGBITS, 0);
                stab_section->sh_entsize = sizeof(Stab_Sym);
                stabstr_section = new_section(".stabstr", SHT_STRTAB, 0);
                put_elf_str(stabstr_section, "");
                stab_section->link = stabstr_section;
                /* put first entry */
                put_stabs("", 0, 0, 0, 0);
            }
        } else 
        /* the following options are only for testing, so not
           documented */
        if (r[1] == 'c') {
            multiple_files = 1;
            output_type = TCC_OUTPUT_OBJ;
        } else if (!strcmp(r + 1, "static")) {
            static_link = 1;
        } else if (!strcmp(r + 1, "shared")) {
            output_type = TCC_OUTPUT_DLL;
        } else if (r[1] == 'o') {
            if (optind >= argc)
                goto show_help;
            multiple_files = 1;
            outfile = argv[optind++];
        } else {
            error("invalid option -- '%s'", r);
        }
    }

    /* if outfile provided without other options, we output an
       executable */
    if (outfile && output_type == TCC_OUTPUT_MEMORY)
        output_type = TCC_OUTPUT_EXE;
    
    /* warning if not supported features */
    if (output_type == TCC_OUTPUT_DLL)
        warning("dll output is currently not supported");
#ifdef CONFIG_TCC_BCHECK
    if (do_bounds_check && output_type != TCC_OUTPUT_MEMORY)
        warning("bounds checking is currently only supported for in-memory execution");
#endif
    
    tcc_set_output_type(s, output_type);

    tcc_add_file(s, argv[optind]);
    if (multiple_files) {
        while ((optind + 1) < argc) {
            optind++;
            r = argv[optind];
            if (r[0] == '-') {
                if (r[1] != '-')
                    error("'--' expected");
                break;
            }
            tcc_add_file(s, r);
        }
    }

    /* add specified libraries */
    for(i = 0; i < nb_libraries;i++) {
        if (tcc_add_library(s, libraries[i]) < 0)
                error("cannot find -l%s", libraries[i]);
    }

    if (do_bench) {
        printf("total: %d idents, %d lines, %d bytes\n", 
               tok_ident - TOK_IDENT, total_lines, total_bytes);
    }

    if (s->output_type != TCC_OUTPUT_MEMORY) {
        tcc_output_file(s, outfile);
        return 0;
    } else {
        return tcc_run(s, argc - optind, argv + optind);
    }
}

#endif