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-rw-r--r--bfd/elflink.c713
1 files changed, 713 insertions, 0 deletions
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 77aae5e..4da5d79 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -6348,6 +6348,716 @@ struct elf_outext_info
struct elf_final_link_info *finfo;
};
+
+/* Support for evaluating a complex relocation.
+
+ Complex relocations are generalized, self-describing relocations. The
+ implementation of them consists of two parts: complex symbols, and the
+ relocations themselves.
+
+ The relocations are use a reserved elf-wide relocation type code (R_RELC
+ external / BFD_RELOC_RELC internal) and an encoding of relocation field
+ information (start bit, end bit, word width, etc) into the addend. This
+ information is extracted from CGEN-generated operand tables within gas.
+
+ Complex symbols are mangled symbols (BSF_RELC external / STT_RELC
+ internal) representing prefix-notation expressions, including but not
+ limited to those sorts of expressions normally encoded as addends in the
+ addend field. The symbol mangling format is:
+
+ <node> := <literal>
+ | <unary-operator> ':' <node>
+ | <binary-operator> ':' <node> ':' <node>
+ ;
+
+ <literal> := 's' <digits=N> ':' <N character symbol name>
+ | 'S' <digits=N> ':' <N character section name>
+ | '#' <hexdigits>
+ ;
+
+ <binary-operator> := as in C
+ <unary-operator> := as in C, plus "0-" for unambiguous negation. */
+
+static void
+set_symbol_value (bfd * bfd_with_globals,
+ struct elf_final_link_info * finfo,
+ int symidx,
+ bfd_vma val)
+{
+ bfd_boolean is_local;
+ Elf_Internal_Sym * sym;
+ struct elf_link_hash_entry ** sym_hashes;
+ struct elf_link_hash_entry * h;
+
+ sym_hashes = elf_sym_hashes (bfd_with_globals);
+ sym = finfo->internal_syms + symidx;
+ is_local = ELF_ST_BIND(sym->st_info) == STB_LOCAL;
+
+ if (is_local)
+ {
+ /* It is a local symbol: move it to the
+ "absolute" section and give it a value. */
+ sym->st_shndx = SHN_ABS;
+ sym->st_value = val;
+ }
+ else
+ {
+ /* It is a global symbol: set its link type
+ to "defined" and give it a value. */
+ h = sym_hashes [symidx];
+ while (h->root.type == bfd_link_hash_indirect
+ || h->root.type == bfd_link_hash_warning)
+ h = (struct elf_link_hash_entry *) h->root.u.i.link;
+ h->root.type = bfd_link_hash_defined;
+ h->root.u.def.value = val;
+ h->root.u.def.section = bfd_abs_section_ptr;
+ }
+}
+
+static bfd_boolean
+resolve_symbol (const char * name,
+ bfd * input_bfd,
+ struct elf_final_link_info * finfo,
+ bfd_vma * result,
+ size_t locsymcount)
+{
+ Elf_Internal_Sym * sym;
+ struct bfd_link_hash_entry * global_entry;
+ const char * candidate = NULL;
+ Elf_Internal_Shdr * symtab_hdr;
+ asection * sec = NULL;
+ size_t i;
+
+ symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
+
+ for (i = 0; i < locsymcount; ++ i)
+ {
+ sym = finfo->internal_syms + i;
+ sec = finfo->sections [i];
+
+ if (ELF_ST_BIND (sym->st_info) != STB_LOCAL)
+ continue;
+
+ candidate = bfd_elf_string_from_elf_section (input_bfd,
+ symtab_hdr->sh_link,
+ sym->st_name);
+#ifdef DEBUG
+ printf ("Comparing string: '%s' vs. '%s' = 0x%x\n",
+ name, candidate, (unsigned int)sym->st_value);
+#endif
+ if (candidate && strcmp (candidate, name) == 0)
+ {
+ * result = sym->st_value;
+
+ if (sym->st_shndx > SHN_UNDEF &&
+ sym->st_shndx < SHN_LORESERVE)
+ {
+#ifdef DEBUG
+ printf ("adjusting for sec '%s' @ 0x%x + 0x%x\n",
+ sec->output_section->name,
+ (unsigned int)sec->output_section->vma,
+ (unsigned int)sec->output_offset);
+#endif
+ * result += sec->output_offset + sec->output_section->vma;
+ }
+#ifdef DEBUG
+ printf ("Found symbol with effective value %8.8x\n", (unsigned int)* result);
+#endif
+ return TRUE;
+ }
+ }
+
+ /* Hmm, haven't found it yet. perhaps it is a global. */
+ global_entry = bfd_link_hash_lookup (finfo->info->hash, name, FALSE, FALSE, TRUE);
+ if (!global_entry)
+ return FALSE;
+
+ if (global_entry->type == bfd_link_hash_defined
+ || global_entry->type == bfd_link_hash_defweak)
+ {
+ * result = global_entry->u.def.value
+ + global_entry->u.def.section->output_section->vma
+ + global_entry->u.def.section->output_offset;
+#ifdef DEBUG
+ printf ("Found GLOBAL symbol '%s' with value %8.8x\n",
+ global_entry->root.string, (unsigned int)*result);
+#endif
+ return TRUE;
+ }
+
+ if (global_entry->type == bfd_link_hash_common)
+ {
+ *result = global_entry->u.def.value +
+ bfd_com_section_ptr->output_section->vma +
+ bfd_com_section_ptr->output_offset;
+#ifdef DEBUG
+ printf ("Found COMMON symbol '%s' with value %8.8x\n",
+ global_entry->root.string, (unsigned int)*result);
+#endif
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+static bfd_boolean
+resolve_section (const char * name,
+ asection * sections,
+ bfd_vma * result)
+{
+ asection * curr;
+ unsigned int len;
+
+ for (curr = sections; curr; curr = curr->next)
+ if (strcmp (curr->name, name) == 0)
+ {
+ *result = curr->vma;
+ return TRUE;
+ }
+
+ /* Hmm. still haven't found it. try pseudo-section names. */
+ for (curr = sections; curr; curr = curr->next)
+ {
+ len = strlen (curr->name);
+ if (len > strlen (name))
+ continue;
+
+ if (strncmp (curr->name, name, len) == 0)
+ {
+ if (strncmp (".end", name + len, 4) == 0)
+ {
+ *result = curr->vma + curr->size;
+ return TRUE;
+ }
+
+ /* Insert more pseudo-section names here, if you like. */
+ }
+ }
+
+ return FALSE;
+}
+
+static void
+undefined_reference (const char * reftype,
+ const char * name)
+{
+ _bfd_error_handler (_("undefined %s reference in complex symbol: %s"), reftype, name);
+}
+
+static bfd_boolean
+eval_symbol (bfd_vma * result,
+ char * sym,
+ char ** advanced,
+ bfd * input_bfd,
+ struct elf_final_link_info * finfo,
+ bfd_vma addr,
+ bfd_vma section_offset,
+ size_t locsymcount,
+ int signed_p)
+{
+ int len;
+ int symlen;
+ bfd_vma a;
+ bfd_vma b;
+ const int bufsz = 4096;
+ char symbuf [bufsz];
+ const char * symend;
+ bfd_boolean symbol_is_section = FALSE;
+
+ len = strlen (sym);
+ symend = sym + len;
+
+ if (len < 1 || len > bufsz)
+ {
+ bfd_set_error (bfd_error_invalid_operation);
+ return FALSE;
+ }
+
+ switch (* sym)
+ {
+ case '.':
+ * result = addr + section_offset;
+ * advanced = sym + 1;
+ return TRUE;
+
+ case '#':
+ ++ sym;
+ * result = strtoul (sym, advanced, 16);
+ return TRUE;
+
+ case 'S':
+ symbol_is_section = TRUE;
+ case 's':
+ ++ sym;
+ symlen = strtol (sym, &sym, 10);
+ ++ sym; /* Skip the trailing ':'. */
+
+ if ((symend < sym) || ((symlen + 1) > bufsz))
+ {
+ bfd_set_error (bfd_error_invalid_operation);
+ return FALSE;
+ }
+
+ memcpy (symbuf, sym, symlen);
+ symbuf [symlen] = '\0';
+ * advanced = sym + symlen;
+
+ /* Is it always possible, with complex symbols, that gas "mis-guessed"
+ the symbol as a section, or vice-versa. so we're pretty liberal in our
+ interpretation here; section means "try section first", not "must be a
+ section", and likewise with symbol. */
+
+ if (symbol_is_section)
+ {
+ if ((resolve_section (symbuf, finfo->output_bfd->sections, result) != TRUE)
+ && (resolve_symbol (symbuf, input_bfd, finfo, result, locsymcount) != TRUE))
+ {
+ undefined_reference ("section", symbuf);
+ return FALSE;
+ }
+ }
+ else
+ {
+ if ((resolve_symbol (symbuf, input_bfd, finfo, result, locsymcount) != TRUE)
+ && (resolve_section (symbuf, finfo->output_bfd->sections,
+ result) != TRUE))
+ {
+ undefined_reference ("symbol", symbuf);
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+
+ /* All that remains are operators. */
+
+#define UNARY_OP(op) \
+ if (strncmp (sym, #op, strlen (#op)) == 0) \
+ { \
+ sym += strlen (#op); \
+ if (* sym == ':') \
+ ++ sym; \
+ if (eval_symbol (& a, sym, & sym, input_bfd, finfo, addr, \
+ section_offset, locsymcount, signed_p) \
+ != TRUE) \
+ return FALSE; \
+ if (signed_p) \
+ * result = op ((signed)a); \
+ else \
+ * result = op a; \
+ * advanced = sym; \
+ return TRUE; \
+ }
+
+#define BINARY_OP(op) \
+ if (strncmp (sym, #op, strlen (#op)) == 0) \
+ { \
+ sym += strlen (#op); \
+ if (* sym == ':') \
+ ++ sym; \
+ if (eval_symbol (& a, sym, & sym, input_bfd, finfo, addr, \
+ section_offset, locsymcount, signed_p) \
+ != TRUE) \
+ return FALSE; \
+ ++ sym; \
+ if (eval_symbol (& b, sym, & sym, input_bfd, finfo, addr, \
+ section_offset, locsymcount, signed_p) \
+ != TRUE) \
+ return FALSE; \
+ if (signed_p) \
+ * result = ((signed) a) op ((signed) b); \
+ else \
+ * result = a op b; \
+ * advanced = sym; \
+ return TRUE; \
+ }
+
+ default:
+ UNARY_OP (0-);
+ BINARY_OP (<<);
+ BINARY_OP (>>);
+ BINARY_OP (==);
+ BINARY_OP (!=);
+ BINARY_OP (<=);
+ BINARY_OP (>=);
+ BINARY_OP (&&);
+ BINARY_OP (||);
+ UNARY_OP (~);
+ UNARY_OP (!);
+ BINARY_OP (*);
+ BINARY_OP (/);
+ BINARY_OP (%);
+ BINARY_OP (^);
+ BINARY_OP (|);
+ BINARY_OP (&);
+ BINARY_OP (+);
+ BINARY_OP (-);
+ BINARY_OP (<);
+ BINARY_OP (>);
+#undef UNARY_OP
+#undef BINARY_OP
+ _bfd_error_handler (_("unknown operator '%c' in complex symbol"), * sym);
+ bfd_set_error (bfd_error_invalid_operation);
+ return FALSE;
+ }
+}
+
+/* Entry point to evaluator, called from elf_link_input_bfd. */
+
+static bfd_boolean
+evaluate_complex_relocation_symbols (bfd * input_bfd,
+ struct elf_final_link_info * finfo,
+ size_t locsymcount)
+{
+ const struct elf_backend_data * bed;
+ Elf_Internal_Shdr * symtab_hdr;
+ struct elf_link_hash_entry ** sym_hashes;
+ asection * reloc_sec;
+ bfd_boolean result = TRUE;
+
+ /* For each section, we're going to check and see if it has any
+ complex relocations, and we're going to evaluate any of them
+ we can. */
+
+ if (finfo->info->relocatable)
+ return TRUE;
+
+ symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
+ sym_hashes = elf_sym_hashes (input_bfd);
+ bed = get_elf_backend_data (input_bfd);
+
+ for (reloc_sec = input_bfd->sections; reloc_sec; reloc_sec = reloc_sec->next)
+ {
+ Elf_Internal_Rela * internal_relocs;
+ unsigned long i;
+
+ /* This section was omitted from the link. */
+ if (! reloc_sec->linker_mark)
+ continue;
+
+ /* Only process sections containing relocs. */
+ if ((reloc_sec->flags & SEC_RELOC) == 0)
+ continue;
+
+ if (reloc_sec->reloc_count == 0)
+ continue;
+
+ /* Read in the relocs for this section. */
+ internal_relocs
+ = _bfd_elf_link_read_relocs (input_bfd, reloc_sec, NULL,
+ (Elf_Internal_Rela *) NULL,
+ FALSE);
+ if (internal_relocs == NULL)
+ continue;
+
+ for (i = reloc_sec->reloc_count; i--;)
+ {
+ Elf_Internal_Rela * rel;
+ char * sym_name;
+ unsigned long index;
+ Elf_Internal_Sym * sym;
+ bfd_vma result;
+ bfd_vma section_offset;
+ bfd_vma addr;
+ int signed_p = 0;
+
+ rel = internal_relocs + i;
+ section_offset = reloc_sec->output_section->vma
+ + reloc_sec->output_offset;
+ addr = rel->r_offset;
+
+ index = ELF32_R_SYM (rel->r_info);
+ if (bed->s->arch_size == 64)
+ index >>= 24;
+
+ if (index < locsymcount)
+ {
+ /* The symbol is local. */
+ sym = finfo->internal_syms + index;
+
+ /* We're only processing STT_RELC or STT_SRELC type symbols. */
+ if ((ELF_ST_TYPE (sym->st_info) != STT_RELC) &&
+ (ELF_ST_TYPE (sym->st_info) != STT_SRELC))
+ continue;
+
+ sym_name = bfd_elf_string_from_elf_section
+ (input_bfd, symtab_hdr->sh_link, sym->st_name);
+
+ signed_p = (ELF_ST_TYPE (sym->st_info) == STT_SRELC);
+ }
+ else
+ {
+ /* The symbol is global. */
+ struct elf_link_hash_entry * h;
+
+ if (elf_bad_symtab (input_bfd))
+ continue;
+
+ h = sym_hashes [index - locsymcount];
+ while ( h->root.type == bfd_link_hash_indirect
+ || h->root.type == bfd_link_hash_warning)
+ h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
+ if (h->type != STT_RELC && h->type != STT_SRELC)
+ continue;
+
+ signed_p = (h->type == STT_SRELC);
+ sym_name = (char *) h->root.root.string;
+ }
+#ifdef DEBUG
+ printf ("Encountered a complex symbol!");
+ printf (" (input_bfd %s, section %s, reloc %ld\n",
+ input_bfd->filename, reloc_sec->name, i);
+ printf (" symbol: idx %8.8lx, name %s\n",
+ index, sym_name);
+ printf (" reloc : info %8.8lx, addr %8.8lx\n",
+ rel->r_info, addr);
+ printf (" Evaluating '%s' ...\n ", sym_name);
+#endif
+ if (eval_symbol (& result, sym_name, & sym_name, input_bfd,
+ finfo, addr, section_offset, locsymcount,
+ signed_p))
+ /* Symbol evaluated OK. Update to absolute value. */
+ set_symbol_value (input_bfd, finfo, index, result);
+
+ else
+ result = FALSE;
+ }
+
+ if (internal_relocs != elf_section_data (reloc_sec)->relocs)
+ free (internal_relocs);
+ }
+
+ /* If nothing went wrong, then we adjusted
+ everything we wanted to adjust. */
+ return result;
+}
+
+static void
+put_value (bfd_vma size,
+ unsigned long chunksz,
+ bfd * input_bfd,
+ bfd_vma x,
+ bfd_byte * location)
+{
+ location += (size - chunksz);
+
+ for (; size; size -= chunksz, location -= chunksz, x >>= (chunksz * 8))
+ {
+ switch (chunksz)
+ {
+ default:
+ case 0:
+ abort ();
+ case 1:
+ bfd_put_8 (input_bfd, x, location);
+ break;
+ case 2:
+ bfd_put_16 (input_bfd, x, location);
+ break;
+ case 4:
+ bfd_put_32 (input_bfd, x, location);
+ break;
+ case 8:
+#ifdef BFD64
+ bfd_put_64 (input_bfd, x, location);
+#else
+ abort ();
+#endif
+ break;
+ }
+ }
+}
+
+static bfd_vma
+get_value (bfd_vma size,
+ unsigned long chunksz,
+ bfd * input_bfd,
+ bfd_byte * location)
+{
+ bfd_vma x = 0;
+
+ for (; size; size -= chunksz, location += chunksz)
+ {
+ switch (chunksz)
+ {
+ default:
+ case 0:
+ abort ();
+ case 1:
+ x = (x << (8 * chunksz)) | bfd_get_8 (input_bfd, location);
+ break;
+ case 2:
+ x = (x << (8 * chunksz)) | bfd_get_16 (input_bfd, location);
+ break;
+ case 4:
+ x = (x << (8 * chunksz)) | bfd_get_32 (input_bfd, location);
+ break;
+ case 8:
+#ifdef BFD64
+ x = (x << (8 * chunksz)) | bfd_get_64 (input_bfd, location);
+#else
+ abort ();
+#endif
+ break;
+ }
+ }
+ return x;
+}
+
+static void
+decode_complex_addend
+ (unsigned long * start, /* in bits */
+ unsigned long * oplen, /* in bits */
+ unsigned long * len, /* in bits */
+ unsigned long * wordsz, /* in bytes */
+ unsigned long * chunksz, /* in bytes */
+ unsigned long * lsb0_p,
+ unsigned long * signed_p,
+ unsigned long * trunc_p,
+ unsigned long encoded)
+{
+ * start = encoded & 0x3F;
+ * len = (encoded >> 6) & 0x3F;
+ * oplen = (encoded >> 12) & 0x3F;
+ * wordsz = (encoded >> 18) & 0xF;
+ * chunksz = (encoded >> 22) & 0xF;
+ * lsb0_p = (encoded >> 27) & 1;
+ * signed_p = (encoded >> 28) & 1;
+ * trunc_p = (encoded >> 29) & 1;
+}
+
+void
+bfd_elf_perform_complex_relocation
+ (bfd * output_bfd ATTRIBUTE_UNUSED,
+ struct bfd_link_info * info,
+ bfd * input_bfd,
+ asection * input_section,
+ bfd_byte * contents,
+ Elf_Internal_Rela * rel,
+ Elf_Internal_Sym * local_syms,
+ asection ** local_sections)
+{
+ const struct elf_backend_data * bed;
+ Elf_Internal_Shdr * symtab_hdr;
+ asection * sec;
+ bfd_vma relocation = 0, shift, x;
+ unsigned long r_symndx;
+ bfd_vma mask;
+ unsigned long start, oplen, len, wordsz,
+ chunksz, lsb0_p, signed_p, trunc_p;
+
+ /* Perform this reloc, since it is complex.
+ (this is not to say that it necessarily refers to a complex
+ symbol; merely that it is a self-describing CGEN based reloc.
+ i.e. the addend has the complete reloc information (bit start, end,
+ word size, etc) encoded within it.). */
+ r_symndx = ELF32_R_SYM (rel->r_info);
+ bed = get_elf_backend_data (input_bfd);
+ if (bed->s->arch_size == 64)
+ r_symndx >>= 24;
+
+#ifdef DEBUG
+ printf ("Performing complex relocation %ld...\n", r_symndx);
+#endif
+
+ symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
+ if (r_symndx < symtab_hdr->sh_info)
+ {
+ /* The symbol is local. */
+ Elf_Internal_Sym * sym;
+
+ sym = local_syms + r_symndx;
+ sec = local_sections [r_symndx];
+ relocation = sym->st_value;
+ if (sym->st_shndx > SHN_UNDEF &&
+ sym->st_shndx < SHN_LORESERVE)
+ relocation += (sec->output_offset +
+ sec->output_section->vma);
+ }
+ else
+ {
+ /* The symbol is global. */
+ struct elf_link_hash_entry **sym_hashes;
+ struct elf_link_hash_entry * h;
+
+ sym_hashes = elf_sym_hashes (input_bfd);
+ h = sym_hashes [r_symndx];
+
+ while (h->root.type == bfd_link_hash_indirect
+ || h->root.type == bfd_link_hash_warning)
+ h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
+ if (h->root.type == bfd_link_hash_defined
+ || h->root.type == bfd_link_hash_defweak)
+ {
+ sec = h->root.u.def.section;
+ relocation = h->root.u.def.value;
+
+ if (! bfd_is_abs_section (sec))
+ relocation += (sec->output_section->vma
+ + sec->output_offset);
+ }
+ if (h->root.type == bfd_link_hash_undefined
+ && !((*info->callbacks->undefined_symbol)
+ (info, h->root.root.string, input_bfd,
+ input_section, rel->r_offset,
+ info->unresolved_syms_in_objects == RM_GENERATE_ERROR
+ || ELF_ST_VISIBILITY (h->other))))
+ return;
+ }
+
+ decode_complex_addend (& start, & oplen, & len, & wordsz,
+ & chunksz, & lsb0_p, & signed_p,
+ & trunc_p, rel->r_addend);
+
+ mask = (((1L << (len - 1)) - 1) << 1) | 1;
+
+ if (lsb0_p)
+ shift = (start + 1) - len;
+ else
+ shift = (8 * wordsz) - (start + len);
+
+ x = get_value (wordsz, chunksz, input_bfd, contents + rel->r_offset);
+
+#ifdef DEBUG
+ printf ("Doing complex reloc: "
+ "lsb0? %ld, signed? %ld, trunc? %ld, wordsz %ld, "
+ "chunksz %ld, start %ld, len %ld, oplen %ld\n"
+ " dest: %8.8lx, mask: %8.8lx, reloc: %8.8lx\n",
+ lsb0_p, signed_p, trunc_p, wordsz, chunksz, start, len,
+ oplen, x, mask, relocation);
+#endif
+
+ if (! trunc_p)
+ {
+ /* Now do an overflow check. */
+ if (bfd_check_overflow ((signed_p ?
+ complain_overflow_signed :
+ complain_overflow_unsigned),
+ len, 0, (8 * wordsz),
+ relocation) == bfd_reloc_overflow)
+ (*_bfd_error_handler)
+ ("%s (%s + 0x%lx): relocation overflow: 0x%lx %sdoes not fit "
+ "within 0x%lx",
+ input_bfd->filename, input_section->name, rel->r_offset,
+ relocation, (signed_p ? "(signed) " : ""), mask);
+ }
+
+ /* Do the deed. */
+ x = (x & ~(mask << shift)) | ((relocation & mask) << shift);
+
+#ifdef DEBUG
+ printf (" relocation: %8.8lx\n"
+ " shifted mask: %8.8lx\n"
+ " shifted/masked reloc: %8.8lx\n"
+ " result: %8.8lx\n",
+ relocation, (mask << shift),
+ ((relocation & mask) << shift), x);
+#endif
+ put_value (wordsz, chunksz, input_bfd, x, contents + rel->r_offset);
+}
+
/* When performing a relocatable link, the input relocations are
preserved. But, if they reference global symbols, the indices
referenced must be updated. Update all the relocations in
@@ -7509,6 +8219,9 @@ elf_link_input_bfd (struct elf_final_link_info *finfo, bfd *input_bfd)
return FALSE;
}
+ if (! evaluate_complex_relocation_symbols (input_bfd, finfo, locsymcount))
+ return FALSE;
+
/* Relocate the contents of each section. */
sym_hashes = elf_sym_hashes (input_bfd);
for (o = input_bfd->sections; o != NULL; o = o->next)
generated by cgit v1.1 at 2024-11-25 10:51:41 +0000