disas.c

   1 /* General "disassemble this chunk" code.  Used for debugging. */
   2 #include "dis-asm.h"
   3 #include "disas.h"
   4 #include "elf.h"
   5
   6 /* Filled in by elfload.c.  Simplistic, but will do for now. */
   7 unsigned int disas_num_syms;
   8 void *disas_symtab;
   9 const char *disas_strtab;
  10
  11 /* Disassemble this for me please... (debugging). */
  12 void disas(FILE *out, void *code, unsigned long size, enum disas_type type)
  13 {
  14     uint8_t *pc;
  15     int count;
  16     struct disassemble_info disasm_info;
  17     int (*print_insn)(bfd_vma pc, disassemble_info *info);
  18
  19     INIT_DISASSEMBLE_INFO(disasm_info, out, fprintf);
  20
  21     disasm_info.buffer = code;
  22     disasm_info.buffer_vma = (unsigned long)code;
  23     disasm_info.buffer_length = size;
  24
  25     if (type == DISAS_TARGET) {
  26 #ifdef WORDS_BIGENDIAN
  27         disasm_info.endian = BFD_ENDIAN_BIG;
  28 #else
  29         disasm_info.endian = BFD_ENDIAN_LITTLE;
  30 #endif
  31 #ifdef __i386__
  32         disasm_info.mach = bfd_mach_i386_i386;
  33         print_insn = print_insn_i386;
  34 #elif defined(__powerpc__)
  35         print_insn = print_insn_ppc;
  36 #elif defined(__alpha__)
  37         print_insn = print_insn_alpha;
  38 #else
  39         fprintf(out, "Asm output not supported on this arch\n");
  40         return;
  41 #endif
  42     } else {
  43         /* Currently only source supported in x86. */
  44         disasm_info.endian = BFD_ENDIAN_LITTLE;
  45         if (type == DISAS_I386_I386)
  46             disasm_info.mach = bfd_mach_i386_i386;
  47         else
  48             disasm_info.mach = bfd_mach_i386_i8086;
  49         print_insn = print_insn_i386;
  50     }
  51
  52     for (pc = code; pc < (uint8_t *)code + size; pc += count) {
  53         fprintf(out, "0x%08lx:  ", (long)pc);
  54         count = print_insn((long)pc, &disasm_info);
  55         fprintf(out, "\n");
  56         if (count < 0)
  57             break;
  58     }
  59 }
  60
  61 /* Look up symbol for debugging purpose.  Returns "" if unknown. */
  62 const char *lookup_symbol(void *orig_addr)
  63 {
  64     unsigned int i;
  65     /* Hack, because we know this is x86. */
  66     Elf32_Sym *sym = disas_symtab;
  67
  68     for (i = 0; i < disas_num_syms; i++) {
  69         if (sym[i].st_shndx == SHN_UNDEF
  70             || sym[i].st_shndx >= SHN_LORESERVE)
  71             continue;
  72
  73         if (ELF_ST_TYPE(sym[i].st_info) != STT_FUNC)
  74             continue;
  75
  76         if ((long)orig_addr >= sym[i].st_value
  77             && (long)orig_addr < sym[i].st_value + sym[i].st_size)
  78             return disas_strtab + sym[i].st_name;
  79     }
  80     return "";
  81 }