+/* Copy all sections in an ELF file. */
+
+static const char *
+simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
+ simple_object_write *dobj,
+ char *(*pfn) (const char *),
+ int *err)
+{
+ struct simple_object_elf_read *eor =
+ (struct simple_object_elf_read *) sobj->data;
+ const struct elf_type_functions *type_functions = eor->type_functions;
+ struct simple_object_elf_write *eow =
+ (struct simple_object_elf_write *) dobj->data;
+ unsigned char ei_class = eor->ei_class;
+ size_t shdr_size;
+ unsigned int shnum;
+ unsigned char *shdrs;
+ const char *errmsg;
+ unsigned char *shstrhdr;
+ size_t name_size;
+ off_t shstroff;
+ unsigned char *names;
+ unsigned int i;
+ int changed;
+ int *pfnret;
+ const char **pfnname;
+ unsigned new_i;
+ unsigned *sh_map;
+ unsigned first_shndx = 0;
+ unsigned int *symtab_indices_shndx;
+
+ shdr_size = (ei_class == ELFCLASS32
+ ? sizeof (Elf32_External_Shdr)
+ : sizeof (Elf64_External_Shdr));
+
+ /* Read the section headers. We skip section 0, which is not a
+ useful section. */
+
+ shnum = eor->shnum;
+ shdrs = XNEWVEC (unsigned char, shdr_size * (shnum - 1));
+
+ if (!simple_object_internal_read (sobj->descriptor,
+ sobj->offset + eor->shoff + shdr_size,
+ shdrs,
+ shdr_size * (shnum - 1),
+ &errmsg, err))
+ {
+ XDELETEVEC (shdrs);
+ return errmsg;
+ }
+
+ /* Read the section names. */
+
+ shstrhdr = shdrs + (eor->shstrndx - 1) * shdr_size;
+ name_size = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shstrhdr, sh_size, Elf_Addr);
+ shstroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shstrhdr, sh_offset, Elf_Addr);
+ names = XNEWVEC (unsigned char, name_size);
+ if (!simple_object_internal_read (sobj->descriptor,
+ sobj->offset + shstroff,
+ names, name_size, &errmsg, err))
+ {
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ return errmsg;
+ }
+
+ pfnret = XNEWVEC (int, shnum);
+ pfnname = XNEWVEC (const char *, shnum);
+
+ /* Map of symtab to index section. */
+ symtab_indices_shndx = XCNEWVEC (unsigned int, shnum - 1);
+
+ /* First perform the callbacks to know which sections to preserve and
+ what name to use for those. */
+ for (i = 1; i < shnum; ++i)
+ {
+ unsigned char *shdr;
+ unsigned int sh_name, sh_type;
+ const char *name;
+ char *ret;
+
+ shdr = shdrs + (i - 1) * shdr_size;
+ sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_name, Elf_Word);
+ if (sh_name >= name_size)
+ {
+ *err = 0;
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ return "ELF section name out of range";
+ }
+
+ name = (const char *) names + sh_name;
+
+ ret = (*pfn) (name);
+ pfnret[i - 1] = ret == NULL ? -1 : 0;
+ pfnname[i - 1] = ret == NULL ? name : ret;
+ if (first_shndx == 0
+ && pfnret[i - 1] == 0)
+ first_shndx = i;
+
+ /* Remember the indexes of existing SHT_SYMTAB_SHNDX sections. */
+ sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_type, Elf_Word);
+ if (sh_type == SHT_SYMTAB_SHNDX)
+ {
+ unsigned int sh_link;
+ sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_link, Elf_Word);
+ symtab_indices_shndx[sh_link - 1] = i;
+ /* Always discard the extended index sections, after
+ copying it will not be needed. This way we don't need to
+ update it and deal with the ordering constraints of
+ processing the existing symtab and changing the index. */
+ pfnret[i - 1] = -1;
+ }
+ }
+
+ /* Mark sections as preserved that are required by to be preserved
+ sections. */
+ do
+ {
+ changed = 0;
+ for (i = 1; i < shnum; ++i)
+ {
+ unsigned char *shdr;
+ unsigned int sh_type, sh_info, sh_link;
+ off_t offset;
+ off_t length;
+
+ shdr = shdrs + (i - 1) * shdr_size;
+ sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_type, Elf_Word);
+ sh_info = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_info, Elf_Word);
+ sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_link, Elf_Word);
+ if (sh_type == SHT_GROUP)
+ {
+ /* Mark groups containing copied sections. */
+ unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class,
+ Shdr, shdr, sh_entsize,
+ Elf_Addr);
+ unsigned char *ent, *buf;
+ int keep = 0;
+ offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_offset, Elf_Addr);
+ length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_size, Elf_Addr);
+ buf = XNEWVEC (unsigned char, length);
+ if (!simple_object_internal_read (sobj->descriptor,
+ sobj->offset + offset, buf,
+ (size_t) length, &errmsg, err))
+ {
+ XDELETEVEC (buf);
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ return errmsg;
+ }
+ for (ent = buf + entsize; ent < buf + length; ent += entsize)
+ {
+ unsigned sec = type_functions->fetch_Elf_Word (ent);
+ if (pfnret[sec - 1] == 0)
+ keep = 1;
+ }
+ if (keep)
+ {
+ changed |= (pfnret[sh_link - 1] == -1
+ || pfnret[i - 1] == -1);
+ pfnret[sh_link - 1] = 0;
+ pfnret[i - 1] = 0;
+ }
+ }
+ if (sh_type == SHT_RELA
+ || sh_type == SHT_REL)
+ {
+ /* Mark relocation sections and symtab of copied sections. */
+ if (pfnret[sh_info - 1] == 0)
+ {
+ changed |= (pfnret[sh_link - 1] == -1
+ || pfnret[i - 1] == -1);
+ pfnret[sh_link - 1] = 0;
+ pfnret[i - 1] = 0;
+ }
+ }
+ if (sh_type == SHT_SYMTAB)
+ {
+ /* Mark strings sections of copied symtabs. */
+ if (pfnret[i - 1] == 0)
+ {
+ changed |= pfnret[sh_link - 1] == -1;
+ pfnret[sh_link - 1] = 0;
+ }
+ }
+ }
+ }
+ while (changed);
+
+ /* Compute a mapping of old -> new section numbers. */
+ sh_map = XNEWVEC (unsigned, shnum);
+ sh_map[0] = 0;
+ new_i = 1;
+ for (i = 1; i < shnum; ++i)
+ {
+ if (pfnret[i - 1] == -1)
+ sh_map[i] = 0;
+ else
+ sh_map[i] = new_i++;
+ }
+ if (new_i - 1 >= SHN_LORESERVE)
+ {
+ *err = ENOTSUP;
+ return "Too many copied sections";
+ }
+ eow->shdrs = XNEWVEC (unsigned char, shdr_size * (new_i - 1));
+
+ /* Then perform the actual copying. */
+ new_i = 0;
+ for (i = 1; i < shnum; ++i)
+ {
+ unsigned char *shdr;
+ unsigned int sh_name, sh_type;
+ const char *name;
+ off_t offset;
+ off_t length;
+ simple_object_write_section *dest;
+ off_t flags;
+ unsigned char *buf;
+
+ if (pfnret[i - 1])
+ continue;
+
+ new_i++;
+ shdr = shdrs + (i - 1) * shdr_size;
+ sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_name, Elf_Word);
+ if (sh_name >= name_size)
+ {
+ *err = 0;
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ XDELETEVEC (symtab_indices_shndx);
+ return "ELF section name out of range";
+ }
+
+ name = pfnname[i - 1];
+ offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_offset, Elf_Addr);
+ length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_size, Elf_Addr);
+ sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_type, Elf_Word);
+
+ dest = simple_object_write_create_section (dobj, pfnname[i - 1],
+ 0, &errmsg, err);
+ if (dest == NULL)
+ {
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ XDELETEVEC (symtab_indices_shndx);
+ return errmsg;
+ }
+
+ /* Record the SHDR of the source. */
+ memcpy (eow->shdrs + (new_i - 1) * shdr_size, shdr, shdr_size);
+ shdr = eow->shdrs + (new_i - 1) * shdr_size;
+
+ /* Copy the data.
+ ??? This is quite wasteful and ideally would be delayed until
+ write_to_file (). Thus it questions the interfacing
+ which eventually should contain destination creation plus
+ writing. */
+ buf = XNEWVEC (unsigned char, length);
+ if (!simple_object_internal_read (sobj->descriptor,
+ sobj->offset + offset, buf,
+ (size_t) length, &errmsg, err))
+ {
+ XDELETEVEC (buf);
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ XDELETEVEC (symtab_indices_shndx);
+ return errmsg;
+ }
+
+ /* If we are processing .symtab purge any symbols
+ in discarded sections. */
+ if (sh_type == SHT_SYMTAB)
+ {
+ unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_entsize, Elf_Addr);
+ unsigned strtab = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_link, Elf_Word);
+ size_t prevailing_name_idx = 0;
+ unsigned char *ent;
+ unsigned *shndx_table = NULL;
+ /* Read the section index table if present. */
+ if (symtab_indices_shndx[i - 1] != 0)
+ {
+ unsigned char *sidxhdr = shdrs + (strtab - 1) * shdr_size;
+ off_t sidxoff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ sidxhdr, sh_offset, Elf_Addr);
+ size_t sidxsz = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ sidxhdr, sh_size, Elf_Addr);
+ shndx_table = (unsigned *)XNEWVEC (char, sidxsz);
+ simple_object_internal_read (sobj->descriptor,
+ sobj->offset + sidxoff,
+ (unsigned char *)shndx_table,
+ sidxsz, &errmsg, err);
+ }
+
+ /* Find a WEAK HIDDEN symbol which name we will use for removed
+ symbols. We know there's a prevailing weak hidden symbol
+ at the start of the .debug_info section. */
+ for (ent = buf; ent < buf + length; ent += entsize)
+ {
+ unsigned st_shndx = ELF_FETCH_FIELD (type_functions, ei_class,
+ Sym, ent,
+ st_shndx, Elf_Half);
+ unsigned char *st_info;
+ unsigned char *st_other;
+ if (ei_class == ELFCLASS32)
+ {
+ st_info = &((Elf32_External_Sym *)ent)->st_info;
+ st_other = &((Elf32_External_Sym *)ent)->st_other;
+ }
+ else
+ {
+ st_info = &((Elf64_External_Sym *)ent)->st_info;
+ st_other = &((Elf64_External_Sym *)ent)->st_other;
+ }
+ if (st_shndx == SHN_XINDEX)
+ st_shndx = type_functions->fetch_Elf_Word
+ ((unsigned char *)(shndx_table + (ent - buf) / entsize));
+
+ if (st_shndx != SHN_COMMON
+ && !(st_shndx != SHN_UNDEF
+ && st_shndx < shnum
+ && pfnret[st_shndx - 1] == -1)
+ && ELF_ST_BIND (*st_info) == STB_WEAK
+ && *st_other == STV_HIDDEN)
+ {
+ prevailing_name_idx = ELF_FETCH_FIELD (type_functions,
+ ei_class, Sym, ent,
+ st_name, Elf_Word);
+ break;
+ }
+ }
+
+ for (ent = buf; ent < buf + length; ent += entsize)
+ {
+ unsigned st_shndx = ELF_FETCH_FIELD (type_functions, ei_class,
+ Sym, ent,
+ st_shndx, Elf_Half);
+ unsigned raw_st_shndx = st_shndx;
+ unsigned char *st_info;
+ unsigned char *st_other;
+ int discard = 0;
+ if (ei_class == ELFCLASS32)
+ {
+ st_info = &((Elf32_External_Sym *)ent)->st_info;
+ st_other = &((Elf32_External_Sym *)ent)->st_other;
+ }
+ else
+ {
+ st_info = &((Elf64_External_Sym *)ent)->st_info;
+ st_other = &((Elf64_External_Sym *)ent)->st_other;
+ }
+ if (st_shndx == SHN_XINDEX)
+ st_shndx = type_functions->fetch_Elf_Word
+ ((unsigned char *)(shndx_table + (ent - buf) / entsize));
+ /* Eliminate all COMMONs - this includes __gnu_lto_slim
+ which otherwise cause endless LTO plugin invocation.
+ FIXME: remove the condition once we remove emission
+ of __gnu_lto_slim symbol. */
+ if (st_shndx == SHN_COMMON)
+ discard = 1;
+ /* We also need to remove symbols refering to sections
+ we'll eventually remove as with fat LTO objects
+ we otherwise get duplicate symbols at final link
+ (with GNU ld, gold is fine and ignores symbols in
+ sections marked as EXCLUDE). ld/20513 */
+ else if (st_shndx != SHN_UNDEF
+ && st_shndx < shnum
+ && pfnret[st_shndx - 1] == -1)
+ discard = 1;
+
+ if (discard)
+ {
+ /* Make discarded symbols undefined and unnamed
+ in case it is local. */
+ int bind = ELF_ST_BIND (*st_info);
+ int other = STV_DEFAULT;
+ if (bind == STB_LOCAL)
+ {
+ /* Make discarded local symbols unnamed and
+ defined in the first prevailing section. */
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_name, Elf_Word, 0);
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_shndx, Elf_Half,
+ sh_map[first_shndx]);
+ }
+ else
+ {
+ /* Make discarded global symbols hidden weak
+ undefined and sharing a name of a prevailing
+ symbol. */
+ bind = STB_WEAK;
+ other = STV_HIDDEN;
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_name, Elf_Word,
+ prevailing_name_idx);
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_shndx, Elf_Half, SHN_UNDEF);
+ }
+ *st_other = other;
+ *st_info = ELF_ST_INFO (bind, STT_NOTYPE);
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_value, Elf_Addr, 0);
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_size, Elf_Word, 0);
+ }
+ else if (raw_st_shndx < SHN_LORESERVE
+ || raw_st_shndx == SHN_XINDEX)
+ /* Remap the section reference. */
+ ELF_SET_FIELD (type_functions, ei_class, Sym,
+ ent, st_shndx, Elf_Half, sh_map[st_shndx]);
+ }
+ XDELETEVEC (shndx_table);
+ }
+ else if (sh_type == SHT_GROUP)
+ {
+ /* Remap section indices in groups and remove removed members. */
+ unsigned char *ent, *dst;
+ for (dst = ent = buf + 4; ent < buf + length; ent += 4)
+ {
+ unsigned shndx = type_functions->fetch_Elf_Word (ent);
+ if (pfnret[shndx - 1] == -1)
+ ;
+ else
+ {
+ type_functions->set_Elf_Word (dst, sh_map[shndx]);
+ dst += 4;
+ }
+ }
+ /* Adjust the length. */
+ length = dst - buf;
+ }
+
+ errmsg = simple_object_write_add_data (dobj, dest,
+ buf, length, 1, err);
+ XDELETEVEC (buf);
+ if (errmsg)
+ {
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ XDELETEVEC (symtab_indices_shndx);
+ return errmsg;
+ }
+
+ flags = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_flags, Elf_Addr);
+ /* Remap the section references. */
+ {
+ unsigned int sh_info, sh_link;
+ if (flags & SHF_INFO_LINK || sh_type == SHT_REL || sh_type == SHT_RELA)
+ {
+ sh_info = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_info, Elf_Word);
+ if (sh_info < SHN_LORESERVE
+ || sh_info > SHN_HIRESERVE)
+ sh_info = sh_map[sh_info];
+ ELF_SET_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_info, Elf_Word, sh_info);
+ }
+ sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_link, Elf_Word);
+ if (sh_link < SHN_LORESERVE
+ || sh_link > SHN_HIRESERVE)
+ sh_link = sh_map[sh_link];
+ ELF_SET_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_link, Elf_Word, sh_link);
+ }
+ /* The debugobj doesn't contain any code, thus no trampolines.
+ Even when the original object needs trampolines, debugobj
+ doesn't. */
+ if (strcmp (name, ".note.GNU-stack") == 0)
+ flags &= ~SHF_EXECINSTR;
+ /* Clear SHF_EXCLUDE on to be preserved sections. */
+ flags &= ~SHF_EXCLUDE;
+ ELF_SET_FIELD (type_functions, ei_class, Shdr,
+ shdr, sh_flags, Elf_Addr, flags);
+ }
+
+ XDELETEVEC (names);
+ XDELETEVEC (shdrs);
+ XDELETEVEC (pfnret);
+ XDELETEVEC (pfnname);
+ XDELETEVEC (symtab_indices_shndx);
+ XDELETEVEC (sh_map);
+
+ return NULL;
+}
+
+