gwj / at91sam9263 · Files

/*
 *  Generic Dynamic compiler generator
 * 
 *  Copyright (c) 2003 Fabrice Bellard
 *

 *  The COFF object format support was extracted from Kazu's QEMU port
 *  to Win32.
 *

 *  Mach-O Support by Matt Reda and Pierre d'Herbemont
 *

 *  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 <string.h>

#include <stdarg.h>
#include <inttypes.h>
#include <unistd.h>
#include <fcntl.h>

#include "config-host.h"

/* NOTE: we test CONFIG_WIN32 instead of _WIN32 to enabled cross
   compilation */
#if defined(CONFIG_WIN32)

#define CONFIG_FORMAT_COFF

#elif defined(CONFIG_DARWIN)
#define CONFIG_FORMAT_MACH

#else
#define CONFIG_FORMAT_ELF
#endif

#ifdef CONFIG_FORMAT_ELF

/* elf format definitions. We use these macros to test the CPU to
   allow cross compilation (this tool must be ran on the build
   platform) */
#if defined(HOST_I386)

#define ELF_CLASS	ELFCLASS32
#define ELF_ARCH	EM_386
#define elf_check_arch(x) ( ((x) == EM_386) || ((x) == EM_486) )
#undef ELF_USES_RELOCA

#elif defined(HOST_X86_64)

#define ELF_CLASS	ELFCLASS64
#define ELF_ARCH	EM_X86_64
#define elf_check_arch(x) ((x) == EM_X86_64)
#define ELF_USES_RELOCA

#elif defined(HOST_PPC)

#define ELF_CLASS	ELFCLASS32
#define ELF_ARCH	EM_PPC
#define elf_check_arch(x) ((x) == EM_PPC)
#define ELF_USES_RELOCA

#elif defined(HOST_S390)

#define ELF_CLASS	ELFCLASS32
#define ELF_ARCH	EM_S390
#define elf_check_arch(x) ((x) == EM_S390)
#define ELF_USES_RELOCA

#elif defined(HOST_ALPHA)

#define ELF_CLASS	ELFCLASS64
#define ELF_ARCH	EM_ALPHA
#define elf_check_arch(x) ((x) == EM_ALPHA)
#define ELF_USES_RELOCA

#elif defined(HOST_IA64)

#define ELF_CLASS	ELFCLASS64
#define ELF_ARCH	EM_IA_64
#define elf_check_arch(x) ((x) == EM_IA_64)
#define ELF_USES_RELOCA

#elif defined(HOST_SPARC)

#define ELF_CLASS	ELFCLASS32
#define ELF_ARCH	EM_SPARC
#define elf_check_arch(x) ((x) == EM_SPARC || (x) == EM_SPARC32PLUS)
#define ELF_USES_RELOCA

#elif defined(HOST_SPARC64)

#define ELF_CLASS	ELFCLASS64
#define ELF_ARCH	EM_SPARCV9
#define elf_check_arch(x) ((x) == EM_SPARCV9)
#define ELF_USES_RELOCA

#elif defined(HOST_ARM)

#define ELF_CLASS	ELFCLASS32
#define ELF_ARCH	EM_ARM
#define elf_check_arch(x) ((x) == EM_ARM)
#define ELF_USES_RELOC

#elif defined(HOST_M68K)

#define ELF_CLASS	ELFCLASS32
#define ELF_ARCH	EM_68K
#define elf_check_arch(x) ((x) == EM_68K)
#define ELF_USES_RELOCA

#else
#error unsupported CPU - please update the code
#endif

#include "elf.h"

#if ELF_CLASS == ELFCLASS32
typedef int32_t host_long;
typedef uint32_t host_ulong;

#define swabls(x) swab32s(x)

#define swablss(x) swab32ss(x)

#else
typedef int64_t host_long;
typedef uint64_t host_ulong;

#define swabls(x) swab64s(x)

#define swablss(x) swab64ss(x)

#endif

#ifdef ELF_USES_RELOCA
#define SHT_RELOC SHT_RELA
#else
#define SHT_RELOC SHT_REL
#endif

#define EXE_RELOC ELF_RELOC
#define EXE_SYM ElfW(Sym)

#endif /* CONFIG_FORMAT_ELF */

#ifdef CONFIG_FORMAT_COFF

typedef int32_t host_long;
typedef uint32_t host_ulong;

#include "a.out.h"

#define FILENAMELEN 256

typedef struct coff_sym {
    struct external_syment *st_syment;
    char st_name[FILENAMELEN];
    uint32_t st_value;
    int  st_size;
    uint8_t st_type;
    uint8_t st_shndx;
} coff_Sym;

typedef struct coff_rel {
    struct external_reloc *r_reloc;
    int  r_offset;
    uint8_t r_type;
} coff_Rel;

#define EXE_RELOC struct coff_rel
#define EXE_SYM struct coff_sym

#endif /* CONFIG_FORMAT_COFF */

#ifdef CONFIG_FORMAT_MACH

#include <mach-o/loader.h>
#include <mach-o/nlist.h>
#include <mach-o/reloc.h>
#include <mach-o/ppc/reloc.h>

# define check_mach_header(x) (x.magic == MH_MAGIC)
typedef int32_t host_long;
typedef uint32_t host_ulong;

struct nlist_extended
{
   union {
   char *n_name; 
   long  n_strx; 
   } n_un;
   unsigned char n_type; 
   unsigned char n_sect; 
   short st_desc;
   unsigned long st_value;
   unsigned long st_size;
};

#define EXE_RELOC struct relocation_info
#define EXE_SYM struct nlist_extended

#endif /* CONFIG_FORMAT_MACH */

#include "bswap.h"

enum {
    OUT_GEN_OP,
    OUT_CODE,
    OUT_INDEX_OP,
};

/* all dynamically generated functions begin with this code */

#define OP_PREFIX "op_"

int do_swap;

void __attribute__((noreturn)) __attribute__((format (printf, 1, 2))) error(const char *fmt, ...)

{

    va_list ap;
    va_start(ap, fmt);
    fprintf(stderr, "dyngen: ");
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    va_end(ap);
    exit(1);
}

void *load_data(int fd, long offset, unsigned int size)
{
    char *data;

    data = malloc(size);
    if (!data)
        return NULL;
    lseek(fd, offset, SEEK_SET);
    if (read(fd, data, size) != size) {
        free(data);
        return NULL;
    }
    return data;

}

int strstart(const char *str, const char *val, const char **ptr)
{
    const char *p, *q;
    p = str;
    q = val;
    while (*q != '\0') {
        if (*p != *q)
            return 0;
        p++;
        q++;
    }
    if (ptr)
        *ptr = p;
    return 1;
}

void pstrcpy(char *buf, int buf_size, const char *str)
{
    int c;
    char *q = buf;

    if (buf_size <= 0)
        return;

    for(;;) {
        c = *str++;
        if (c == 0 || q >= buf + buf_size - 1)
            break;
        *q++ = c;
    }
    *q = '\0';
}

void swab16s(uint16_t *p)
{
    *p = bswap16(*p);
}

void swab32s(uint32_t *p)
{
    *p = bswap32(*p);
}

void swab32ss(int32_t *p)
{
    *p = bswap32(*p);
}

void swab64s(uint64_t *p)

{
    *p = bswap64(*p);
}

void swab64ss(int64_t *p)
{
    *p = bswap64(*p);
}

uint16_t get16(uint16_t *p)
{
    uint16_t val;
    val = *p;
    if (do_swap)
        val = bswap16(val);
    return val;
}

uint32_t get32(uint32_t *p)
{
    uint32_t val;
    val = *p;
    if (do_swap)
        val = bswap32(val);
    return val;
}

void put16(uint16_t *p, uint16_t val)
{
    if (do_swap)
        val = bswap16(val);
    *p = val;
}

void put32(uint32_t *p, uint32_t val)
{
    if (do_swap)
        val = bswap32(val);
    *p = val;
}

/* executable information */
EXE_SYM *symtab;
int nb_syms;
int text_shndx;
uint8_t *text;
EXE_RELOC *relocs;
int nb_relocs;

#ifdef CONFIG_FORMAT_ELF

/* ELF file info */
struct elf_shdr *shdr;
uint8_t **sdata;
struct elfhdr ehdr;
char *strtab;

int elf_must_swap(struct elfhdr *h)
{
  union {
      uint32_t i;
      uint8_t b[4];
  } swaptest;

  swaptest.i = 1;
  return (h->e_ident[EI_DATA] == ELFDATA2MSB) != 
      (swaptest.b[0] == 0);
}

void elf_swap_ehdr(struct elfhdr *h)

{
    swab16s(&h->e_type);			/* Object file type */
    swab16s(&h->	e_machine);		/* Architecture */
    swab32s(&h->	e_version);		/* Object file version */

    swabls(&h->	e_entry);		/* Entry point virtual address */
    swabls(&h->	e_phoff);		/* Program header table file offset */
    swabls(&h->	e_shoff);		/* Section header table file offset */

    swab32s(&h->	e_flags);		/* Processor-specific flags */
    swab16s(&h->	e_ehsize);		/* ELF header size in bytes */
    swab16s(&h->	e_phentsize);		/* Program header table entry size */
    swab16s(&h->	e_phnum);		/* Program header table entry count */
    swab16s(&h->	e_shentsize);		/* Section header table entry size */
    swab16s(&h->	e_shnum);		/* Section header table entry count */
    swab16s(&h->	e_shstrndx);		/* Section header string table index */
}

void elf_swap_shdr(struct elf_shdr *h)

{
  swab32s(&h->	sh_name);		/* Section name (string tbl index) */
  swab32s(&h->	sh_type);		/* Section type */

  swabls(&h->	sh_flags);		/* Section flags */
  swabls(&h->	sh_addr);		/* Section virtual addr at execution */
  swabls(&h->	sh_offset);		/* Section file offset */
  swabls(&h->	sh_size);		/* Section size in bytes */

  swab32s(&h->	sh_link);		/* Link to another section */
  swab32s(&h->	sh_info);		/* Additional section information */

  swabls(&h->	sh_addralign);		/* Section alignment */
  swabls(&h->	sh_entsize);		/* Entry size if section holds table */

}

void elf_swap_phdr(struct elf_phdr *h)

{
    swab32s(&h->p_type);			/* Segment type */

    swabls(&h->p_offset);		/* Segment file offset */
    swabls(&h->p_vaddr);		/* Segment virtual address */
    swabls(&h->p_paddr);		/* Segment physical address */
    swabls(&h->p_filesz);		/* Segment size in file */
    swabls(&h->p_memsz);		/* Segment size in memory */

    swab32s(&h->p_flags);		/* Segment flags */

    swabls(&h->p_align);		/* Segment alignment */

}

void elf_swap_rel(ELF_RELOC *rel)
{
    swabls(&rel->r_offset);
    swabls(&rel->r_info);
#ifdef ELF_USES_RELOCA

    swablss(&rel->r_addend);

#endif
}

struct elf_shdr *find_elf_section(struct elf_shdr *shdr, int shnum, const char *shstr, 
                                  const char *name)
{
    int i;
    const char *shname;
    struct elf_shdr *sec;

    for(i = 0; i < shnum; i++) {
        sec = &shdr[i];
        if (!sec->sh_name)
            continue;
        shname = shstr + sec->sh_name;
        if (!strcmp(shname, name))
            return sec;
    }
    return NULL;
}

int find_reloc(int sh_index)

{

    struct elf_shdr *sec;
    int i;

    for(i = 0; i < ehdr.e_shnum; i++) {
        sec = &shdr[i];
        if (sec->sh_type == SHT_RELOC && sec->sh_info == sh_index) 
            return i;
    }
    return 0;

}

static host_ulong get_rel_offset(EXE_RELOC *rel)
{
    return rel->r_offset;
}

static char *get_rel_sym_name(EXE_RELOC *rel)

{

    return strtab + symtab[ELFW(R_SYM)(rel->r_info)].st_name;
}

static char *get_sym_name(EXE_SYM *sym)
{
    return strtab + sym->st_name;
}

/* load an elf object file */
int load_object(const char *filename)
{
    int fd;
    struct elf_shdr *sec, *symtab_sec, *strtab_sec, *text_sec;
    int i, j;
    ElfW(Sym) *sym;
    char *shstr;
    ELF_RELOC *rel;

    fd = open(filename, O_RDONLY);
    if (fd < 0) 
        error("can't open file '%s'", filename);

    /* Read ELF header.  */
    if (read(fd, &ehdr, sizeof (ehdr)) != sizeof (ehdr))
        error("unable to read file header");

    /* Check ELF identification.  */
    if (ehdr.e_ident[EI_MAG0] != ELFMAG0
     || ehdr.e_ident[EI_MAG1] != ELFMAG1
     || ehdr.e_ident[EI_MAG2] != ELFMAG2
     || ehdr.e_ident[EI_MAG3] != ELFMAG3
     || ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
        error("bad ELF header");
    }

    do_swap = elf_must_swap(&ehdr);

    if (do_swap)

        elf_swap_ehdr(&ehdr);
    if (ehdr.e_ident[EI_CLASS] != ELF_CLASS)
        error("Unsupported ELF class");
    if (ehdr.e_type != ET_REL)
        error("ELF object file expected");
    if (ehdr.e_version != EV_CURRENT)
        error("Invalid ELF version");
    if (!elf_check_arch(ehdr.e_machine))
        error("Unsupported CPU (e_machine=%d)", ehdr.e_machine);

    /* read section headers */
    shdr = load_data(fd, ehdr.e_shoff, ehdr.e_shnum * sizeof(struct elf_shdr));
    if (do_swap) {
        for(i = 0; i < ehdr.e_shnum; i++) {
            elf_swap_shdr(&shdr[i]);
        }
    }

    /* read all section data */
    sdata = malloc(sizeof(void *) * ehdr.e_shnum);
    memset(sdata, 0, sizeof(void *) * ehdr.e_shnum);

    for(i = 0;i < ehdr.e_shnum; i++) {
        sec = &shdr[i];
        if (sec->sh_type != SHT_NOBITS)
            sdata[i] = load_data(fd, sec->sh_offset, sec->sh_size);
    }

    sec = &shdr[ehdr.e_shstrndx];

    shstr = (char *)sdata[ehdr.e_shstrndx];

    /* swap relocations */
    for(i = 0; i < ehdr.e_shnum; i++) {
        sec = &shdr[i];
        if (sec->sh_type == SHT_RELOC) {
            nb_relocs = sec->sh_size / sec->sh_entsize;
            if (do_swap) {
                for(j = 0, rel = (ELF_RELOC *)sdata[i]; j < nb_relocs; j++, rel++)
                    elf_swap_rel(rel);
            }
        }
    }
    /* text section */

    text_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".text");
    if (!text_sec)
        error("could not find .text section");
    text_shndx = text_sec - shdr;
    text = sdata[text_shndx];

    /* find text relocations, if any */
    relocs = NULL;
    nb_relocs = 0;
    i = find_reloc(text_shndx);
    if (i != 0) {
        relocs = (ELF_RELOC *)sdata[i];
        nb_relocs = shdr[i].sh_size / shdr[i].sh_entsize;
    }

    symtab_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".symtab");
    if (!symtab_sec)
        error("could not find .symtab section");
    strtab_sec = &shdr[symtab_sec->sh_link];

    symtab = (ElfW(Sym) *)sdata[symtab_sec - shdr];

    strtab = (char *)sdata[symtab_sec->sh_link];

    nb_syms = symtab_sec->sh_size / sizeof(ElfW(Sym));
    if (do_swap) {
        for(i = 0, sym = symtab; i < nb_syms; i++, sym++) {
            swab32s(&sym->st_name);
            swabls(&sym->st_value);
            swabls(&sym->st_size);
            swab16s(&sym->st_shndx);
        }
    }
    close(fd);
    return 0;
}

#endif /* CONFIG_FORMAT_ELF */

#ifdef CONFIG_FORMAT_COFF

/* COFF file info */
struct external_scnhdr *shdr;
uint8_t **sdata;
struct external_filehdr fhdr;
struct external_syment *coff_symtab;
char *strtab;
int coff_text_shndx, coff_data_shndx;

int data_shndx;

#define STRTAB_SIZE 4

#define DIR32   0x06
#define DISP32  0x14

#define T_FUNCTION  0x20
#define C_EXTERNAL  2

void sym_ent_name(struct external_syment *ext_sym, EXE_SYM *sym)
{
    char *q;
    int c, i, len;

    if (ext_sym->e.e.e_zeroes != 0) {
        q = sym->st_name;
        for(i = 0; i < 8; i++) {
            c = ext_sym->e.e_name[i];
            if (c == '\0')
                break;
            *q++ = c;
        }
        *q = '\0';
    } else {
        pstrcpy(sym->st_name, sizeof(sym->st_name), strtab + ext_sym->e.e.e_offset);
    }

    /* now convert the name to a C name (suppress the leading '_') */
    if (sym->st_name[0] == '_') {
        len = strlen(sym->st_name);
        memmove(sym->st_name, sym->st_name + 1, len - 1);
        sym->st_name[len - 1] = '\0';
    }

}

char *name_for_dotdata(struct coff_rel *rel)

{

	int i;
	struct coff_sym *sym;
	uint32_t text_data;

	text_data = *(uint32_t *)(text + rel->r_offset);

	for (i = 0, sym = symtab; i < nb_syms; i++, sym++) {
		if (sym->st_syment->e_scnum == data_shndx &&
                    text_data >= sym->st_value &&
                    text_data < sym->st_value + sym->st_size) {

                    return sym->st_name;

		}
	}
	return NULL;

}

static char *get_sym_name(EXE_SYM *sym)

{

    return sym->st_name;

}

static char *get_rel_sym_name(EXE_RELOC *rel)

{

    char *name;
    name = get_sym_name(symtab + *(uint32_t *)(rel->r_reloc->r_symndx));
    if (!strcmp(name, ".data"))
        name = name_for_dotdata(rel);

    if (name[0] == '.')
        return NULL;

    return name;

}

static host_ulong get_rel_offset(EXE_RELOC *rel)
{
    return rel->r_offset;
}

struct external_scnhdr *find_coff_section(struct external_scnhdr *shdr, int shnum, const char *name)

{
    int i;
    const char *shname;

    struct external_scnhdr *sec;

    for(i = 0; i < shnum; i++) {
        sec = &shdr[i];

        if (!sec->s_name)

            continue;

        shname = sec->s_name;

        if (!strcmp(shname, name))
            return sec;
    }
    return NULL;
}

/* load a coff object file */
int load_object(const char *filename)

{

    int fd;
    struct external_scnhdr *sec, *text_sec, *data_sec;

    int i;

    struct external_syment *ext_sym;
    struct external_reloc *coff_relocs;
    struct external_reloc *ext_rel;
    uint32_t *n_strtab;
    EXE_SYM *sym;
    EXE_RELOC *rel;

    fd = open(filename, O_RDONLY 
#ifdef _WIN32
              | O_BINARY
#endif
              );
    if (fd < 0) 
        error("can't open file '%s'", filename);

    /* Read COFF header.  */
    if (read(fd, &fhdr, sizeof (fhdr)) != sizeof (fhdr))
        error("unable to read file header");

    /* Check COFF identification.  */
    if (fhdr.f_magic != I386MAGIC) {
        error("bad COFF header");
    }
    do_swap = 0;

    /* read section headers */
    shdr = load_data(fd, sizeof(struct external_filehdr) + fhdr.f_opthdr, fhdr.f_nscns * sizeof(struct external_scnhdr));

    /* read all section data */
    sdata = malloc(sizeof(void *) * fhdr.f_nscns);
    memset(sdata, 0, sizeof(void *) * fhdr.f_nscns);

    const char *p;
    for(i = 0;i < fhdr.f_nscns; i++) {

        sec = &shdr[i];

        if (!strstart(sec->s_name,  ".bss", &p))
            sdata[i] = load_data(fd, sec->s_scnptr, sec->s_size);

    }

    /* text section */
    text_sec = find_coff_section(shdr, fhdr.f_nscns, ".text");
    if (!text_sec)
        error("could not find .text section");
    coff_text_shndx = text_sec - shdr;
    text = sdata[coff_text_shndx];

    /* data section */
    data_sec = find_coff_section(shdr, fhdr.f_nscns, ".data");
    if (!data_sec)
        error("could not find .data section");
    coff_data_shndx = data_sec - shdr;

    coff_symtab = load_data(fd, fhdr.f_symptr, fhdr.f_nsyms*SYMESZ);
    for (i = 0, ext_sym = coff_symtab; i < nb_syms; i++, ext_sym++) {
        for(i=0;i<8;i++)
            printf(" %02x", ((uint8_t *)ext_sym->e.e_name)[i]);
        printf("\n");

    }

    n_strtab = load_data(fd, (fhdr.f_symptr + fhdr.f_nsyms*SYMESZ), STRTAB_SIZE);
    strtab = load_data(fd, (fhdr.f_symptr + fhdr.f_nsyms*SYMESZ), *n_strtab); 

    nb_syms = fhdr.f_nsyms;

    for (i = 0, ext_sym = coff_symtab; i < nb_syms; i++, ext_sym++) {
      if (strstart(ext_sym->e.e_name, ".text", NULL))
		  text_shndx = ext_sym->e_scnum;
	  if (strstart(ext_sym->e.e_name, ".data", NULL))
		  data_shndx = ext_sym->e_scnum;

    }

	/* set coff symbol */
	symtab = malloc(sizeof(struct coff_sym) * nb_syms);

	int aux_size, j;
	for (i = 0, ext_sym = coff_symtab, sym = symtab; i < nb_syms; i++, ext_sym++, sym++) {
		memset(sym, 0, sizeof(*sym));
		sym->st_syment = ext_sym;
		sym_ent_name(ext_sym, sym);
		sym->st_value = ext_sym->e_value;

		aux_size = *(int8_t *)ext_sym->e_numaux;
		if (ext_sym->e_scnum == text_shndx && ext_sym->e_type == T_FUNCTION) {
			for (j = aux_size + 1; j < nb_syms - i; j++) {
				if ((ext_sym + j)->e_scnum == text_shndx &&
					(ext_sym + j)->e_type == T_FUNCTION ){
					sym->st_size = (ext_sym + j)->e_value - ext_sym->e_value;
					break;
				} else if (j == nb_syms - i - 1) {
					sec = &shdr[coff_text_shndx];
					sym->st_size = sec->s_size - ext_sym->e_value;
					break;
				}
			}
		} else if (ext_sym->e_scnum == data_shndx && *(uint8_t *)ext_sym->e_sclass == C_EXTERNAL) {
			for (j = aux_size + 1; j < nb_syms - i; j++) {
				if ((ext_sym + j)->e_scnum == data_shndx) {
					sym->st_size = (ext_sym + j)->e_value - ext_sym->e_value;
					break;
				} else if (j == nb_syms - i - 1) {
					sec = &shdr[coff_data_shndx];
					sym->st_size = sec->s_size - ext_sym->e_value;
					break;
				}
			}
		} else {
			sym->st_size = 0;
		}

		sym->st_type = ext_sym->e_type;
		sym->st_shndx = ext_sym->e_scnum;
	}


    /* find text relocations, if any */
    sec = &shdr[coff_text_shndx];
    coff_relocs = load_data(fd, sec->s_relptr, sec->s_nreloc*RELSZ);
    nb_relocs = sec->s_nreloc;

    /* set coff relocation */
    relocs = malloc(sizeof(struct coff_rel) * nb_relocs);
    for (i = 0, ext_rel = coff_relocs, rel = relocs; i < nb_relocs; 
         i++, ext_rel++, rel++) {
        memset(rel, 0, sizeof(*rel));
        rel->r_reloc = ext_rel;
        rel->r_offset = *(uint32_t *)ext_rel->r_vaddr;
        rel->r_type = *(uint16_t *)ext_rel->r_type;
    }
    return 0;

}

#endif /* CONFIG_FORMAT_COFF */

#ifdef CONFIG_FORMAT_MACH

/* File Header */
struct mach_header 	mach_hdr;

/* commands */
struct segment_command 	*segment = 0;
struct dysymtab_command *dysymtabcmd = 0;
struct symtab_command 	*symtabcmd = 0;

/* section */
struct section 	*section_hdr;
struct section *text_sec_hdr;
uint8_t 	**sdata;

/* relocs */
struct relocation_info *relocs;

/* symbols */
EXE_SYM			*symtab;
struct nlist 	*symtab_std;
char			*strtab;

/* indirect symbols */
uint32_t 	*tocdylib;

/* Utility functions */

static inline char *find_str_by_index(int index)
{
    return strtab+index;
}

/* Used by dyngen common code */
static char *get_sym_name(EXE_SYM *sym)
{
	char *name = find_str_by_index(sym->n_un.n_strx);

	if ( sym->n_type & N_STAB ) /* Debug symbols are ignored */
		return "debug";

	if(!name)
		return name;
	if(name[0]=='_')
		return name + 1;
	else
		return name;
}

/* find a section index given its segname, sectname */
static int find_mach_sec_index(struct section *section_hdr, int shnum, const char *segname, 
                                  const char *sectname)
{
    int i;
    struct section *sec = section_hdr;

    for(i = 0; i < shnum; i++, sec++) {
        if (!sec->segname || !sec->sectname)
            continue;
        if (!strcmp(sec->sectname, sectname) && !strcmp(sec->segname, segname))
            return i;
    }
    return -1;
}

/* find a section header given its segname, sectname */
struct section *find_mach_sec_hdr(struct section *section_hdr, int shnum, const char *segname, 
                                  const char *sectname)
{
    int index = find_mach_sec_index(section_hdr, shnum, segname, sectname);
	if(index == -1)
		return NULL;
	return section_hdr+index;
}


static inline void fetch_next_pair_value(struct relocation_info * rel, unsigned int *value)
{
    struct scattered_relocation_info * scarel;

    if(R_SCATTERED & rel->r_address) {
        scarel = (struct scattered_relocation_info*)rel;
        if(scarel->r_type != PPC_RELOC_PAIR)
            error("fetch_next_pair_value: looking for a pair which was not found (1)");
        *value = scarel->r_value;
    } else {
		if(rel->r_type != PPC_RELOC_PAIR)
			error("fetch_next_pair_value: looking for a pair which was not found (2)");
		*value = rel->r_address;
	}
}

/* find a sym name given its value, in a section number */
static const char * find_sym_with_value_and_sec_number( int value, int sectnum, int * offset )
{
	int i, ret = -1;

	for( i = 0 ; i < nb_syms; i++ )
	{
	    if( !(symtab[i].n_type & N_STAB) && (symtab[i].n_type & N_SECT) &&
			 (symtab[i].n_sect ==  sectnum) && (symtab[i].st_value <= value) )
		{
			if( (ret<0) || (symtab[i].st_value >= symtab[ret].st_value) )
				ret = i;
		}
	}
	if( ret < 0 ) {
		*offset = 0;
		return 0;
	} else {
		*offset = value - symtab[ret].st_value;
		return get_sym_name(&symtab[ret]);
	}
}

/* 
 *  Find symbol name given a (virtual) address, and a section which is of type 
 *  S_NON_LAZY_SYMBOL_POINTERS or S_LAZY_SYMBOL_POINTERS or S_SYMBOL_STUBS
 */
static const char * find_reloc_name_in_sec_ptr(int address, struct section * sec_hdr)
{
    unsigned int tocindex, symindex, size;
    const char *name = 0;

    /* Sanity check */
    if(!( address >= sec_hdr->addr && address < (sec_hdr->addr + sec_hdr->size) ) )
        return (char*)0;

	if( sec_hdr->flags & S_SYMBOL_STUBS ){
		size = sec_hdr->reserved2;
		if(size == 0)
		    error("size = 0");

	}
	else if( sec_hdr->flags & S_LAZY_SYMBOL_POINTERS ||
	            sec_hdr->flags & S_NON_LAZY_SYMBOL_POINTERS)
		size = sizeof(unsigned long);
	else
		return 0;

    /* Compute our index in toc */
	tocindex = (address - sec_hdr->addr)/size;
	symindex = tocdylib[sec_hdr->reserved1 + tocindex];

	name = get_sym_name(&symtab[symindex]);

    return name;
}

static const char * find_reloc_name_given_its_address(int address)
{
    unsigned int i;
    for(i = 0; i < segment->nsects ; i++)
    {
        const char * name = find_reloc_name_in_sec_ptr(address, &section_hdr[i]);
        if((long)name != -1)
            return name;
    }
    return 0;
}

static const char * get_reloc_name(EXE_RELOC * rel, int * sslide)
{
	char * name = 0;
	struct scattered_relocation_info * sca_rel = (struct scattered_relocation_info*)rel;
	int sectnum = rel->r_symbolnum;
	int sectoffset;
	int other_half=0;

	/* init the slide value */
	*sslide = 0;

	if(R_SCATTERED & rel->r_address)
		return (char *)find_reloc_name_given_its_address(sca_rel->r_value);

	if(rel->r_extern)
	{
		/* ignore debug sym */
		if ( symtab[rel->r_symbolnum].n_type & N_STAB ) 
			return 0;
		return get_sym_name(&symtab[rel->r_symbolnum]);
	}

	/* Intruction contains an offset to the symbols pointed to, in the rel->r_symbolnum section */
	sectoffset = *(uint32_t *)(text + rel->r_address) & 0xffff;

	if(sectnum==0xffffff)
		return 0;

	/* Sanity Check */
	if(sectnum > segment->nsects)
		error("sectnum > segment->nsects");

	switch(rel->r_type)
	{