diff options
Diffstat (limited to 'bfd/elf.c')
| -rw-r--r-- | bfd/elf.c | 57 |
1 files changed, 57 insertions, 0 deletions
@@ -1203,6 +1203,63 @@ _bfd_elf_copy_private_bfd_data (bfd *ibfd, bfd *obfd) /* Copy object attributes. */ _bfd_elf_copy_obj_attributes (ibfd, obfd); + + /* This is an feature for objcopy --only-keep-debug: When a section's type + is changed to NOBITS, we preserve the sh_link and sh_info fields so that + they can be matched up with the original. */ + Elf_Internal_Shdr ** iheaders = elf_elfsections (ibfd); + Elf_Internal_Shdr ** oheaders = elf_elfsections (obfd); + + if (iheaders != NULL && oheaders != NULL) + { + unsigned int i; + + for (i = 0; i < elf_numsections (obfd); i++) + { + unsigned int j; + Elf_Internal_Shdr * oheader = oheaders[i]; + + if (oheader == NULL + || oheader->sh_type != SHT_NOBITS + || oheader->sh_size == 0 + || (oheader->sh_info != 0 && oheader->sh_link != 0)) + continue; + + /* Scan for the matching section in the input bfd. + FIXME: We could use something better than a linear scan here. + Unfortunately we cannot compare names as the output string table + is empty, so instead we check size, address and type. */ + for (j = 0; j < elf_numsections (ibfd); j++) + { + Elf_Internal_Shdr * iheader = iheaders[j]; + + if (iheader->sh_type != SHT_NOBITS + && iheader->sh_size == oheader->sh_size + && iheader->sh_addr == oheader->sh_addr + && (iheader->sh_info != oheader->sh_info + || iheader->sh_link != oheader->sh_link)) + { + /* Note: Strictly speaking these assignments are wrong. + The sh_link and sh_info fields should point to the + relevent sections in the output BFD, which may not be in + the same location as they were in the input BFD. But the + whole point of this action is to preserve the original + values of the sh_link and sh_info fields, so that they + can be matched up with the section headers in the + original file. So strictly speaking we may be creating + an invalid ELF file, but it is only for a file that just + contains debug info and only for sections without any + contents. */ + if (oheader->sh_link == 0) + oheader->sh_link = iheader->sh_link; + if (oheader->sh_info == 0) + oheader->sh_info = iheader->sh_info; + break; + } + } + } + } + return TRUE; } |