diff options
| -rw-r--r-- | bfd/ChangeLog | 27 | ||||
| -rw-r--r-- | bfd/elf-bfd.h | 24 | ||||
| -rw-r--r-- | bfd/elf-eh-frame.c | 377 | ||||
| -rw-r--r-- | bfd/elflink.c | 3 |
4 files changed, 274 insertions, 157 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 99ce82f..54c909b 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,32 @@ 2007-12-15 Richard Sandiford <rsandifo@nildram.co.uk> + * elf-bfd.h (eh_cie_fde): Add u.cie. Document how u.fde.cie_inf + changes when removed == 0. + (eh_frame_hdr_info): Add parsed_eh_frames. + (_bfd_elf_begin_eh_frame_parsing): Declare. + (_bfd_elf_parse_eh_frame): Declare. + (_bfd_elf_end_eh_frame_parsing): Declare. + * elf-eh-frame.c (_bfd_elf_begin_eh_frame_parsing): New function. + (_bfd_elf_parse_eh_frame): New function, split out from + _bfd_elf_discard_section_eh_frame. Make a first pass through the + buffer to calculate the number of entries and CIEs. Allocate memory + for them before the main loop. Replace current extended cie + representation with a pair of pointers, one to the local eh_cie_fde + and one to the full struct cie. Allocate a separate array of struct + cies if not merging. Merge CIEs during the main loop and set up each + u.cie.merged field. Point an FDE's cie_inf field directly at the + local CIE. Initially assume that all entries should be removed. + (_bfd_elf_end_eh_frame_parsing): New function. + (_bfd_elf_discard_section_eh_frame): Assume that the section has + already been parsed. Use a separate pass to mark entries that + need to be kept. Use the u.cie.merged field to track a CIE's + group representative. + * elflink.c (bfd_elf_discard_info): Call _bfd_elf_parse_eh_frame + before _bfd_elf_discard_section_eh_frame. Wrap loop with calls to + _bfd_elf_begin_eh_frame_parsing and _bfd_elf_end_eh_frame_parsing. + +2007-12-15 Richard Sandiford <rsandifo@nildram.co.uk> + * elf-bfd.h (eh_cie_fde): Put cie_inf in a union. Add a reloc_index field. Use bitfields for fde_encoding, lsda_encoding and lsda_offset. * elf-eh-frame.c (extra_augmentation_data_bytes): Adjust cie_inf diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h index 42a1f74..c91af27 100644 --- a/bfd/elf-bfd.h +++ b/bfd/elf-bfd.h @@ -266,9 +266,22 @@ struct eh_cie_fde { union { struct { - /* The CIE that we have chosen to use for this FDE. */ + /* If REMOVED == 1, this is the CIE that the FDE originally used. + The CIE belongs to the same .eh_frame input section as the FDE. + + If REMOVED == 0, this is the CIE that we have chosen to use for + the output FDE. The CIE's REMOVED field is also 0, but the CIE + might belong to a different .eh_frame input section from the FDE. */ struct eh_cie_fde *cie_inf; } fde; + struct { + /* In general, equivalent CIEs are grouped together, with one CIE + representing all the others in a group. If REMOVED == 0, + this CIE is the group representative. If REMOVED == 1, + following this pointer brings us "closer" to the CIE's group + representative, and reapplying always gives the representative. */ + struct eh_cie_fde *merged; + } cie; } u; unsigned int reloc_index; unsigned int size; @@ -308,6 +321,8 @@ struct eh_frame_hdr_info asection *hdr_sec; unsigned int fde_count, array_count; struct eh_frame_array_ent *array; + /* TRUE if all .eh_frames have been parsd. */ + bfd_boolean parsed_eh_frames; /* TRUE if .eh_frame_hdr should contain the sorted search table. We build it if we successfully read all .eh_frame input sections and recognize them. */ @@ -1723,6 +1738,13 @@ extern bfd_boolean _bfd_elf_strtab_emit extern void _bfd_elf_strtab_finalize (struct elf_strtab_hash *); +extern void _bfd_elf_begin_eh_frame_parsing + (struct bfd_link_info *info); +extern void _bfd_elf_parse_eh_frame + (bfd *, struct bfd_link_info *, asection *, struct elf_reloc_cookie *); +extern void _bfd_elf_end_eh_frame_parsing + (struct bfd_link_info *info); + extern bfd_boolean _bfd_elf_discard_section_eh_frame (bfd *, struct bfd_link_info *, asection *, bfd_boolean (*) (bfd_vma, void *), struct elf_reloc_cookie *); diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c index 1037cdc..63b6ba4 100644 --- a/bfd/elf-eh-frame.c +++ b/bfd/elf-eh-frame.c @@ -431,16 +431,26 @@ skip_non_nops (bfd_byte *buf, bfd_byte *end, unsigned int encoded_ptr_width, return last; } -/* This function is called for each input file before the .eh_frame - section is relocated. It discards duplicate CIEs and FDEs for discarded - functions. The function returns TRUE iff any entries have been - deleted. */ +/* Called before calling _bfd_elf_parse_eh_frame on every input bfd's + .eh_frame section. */ -bfd_boolean -_bfd_elf_discard_section_eh_frame - (bfd *abfd, struct bfd_link_info *info, asection *sec, - bfd_boolean (*reloc_symbol_deleted_p) (bfd_vma, void *), - struct elf_reloc_cookie *cookie) +void +_bfd_elf_begin_eh_frame_parsing (struct bfd_link_info *info) +{ + struct eh_frame_hdr_info *hdr_info; + + hdr_info = &elf_hash_table (info)->eh_info; + if (!hdr_info->parsed_eh_frames && !info->relocatable) + hdr_info->cies = htab_try_create (1, cie_hash, cie_eq, free); +} + +/* Try to parse .eh_frame section SEC, which belongs to ABFD. Store the + information in the section's sec_info field on success. COOKIE + describes the relocations in SEC. */ + +void +_bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info, + asection *sec, struct elf_reloc_cookie *cookie) { #define REQUIRE(COND) \ do \ @@ -448,45 +458,42 @@ _bfd_elf_discard_section_eh_frame goto free_no_table; \ while (0) - bfd_byte *ehbuf = NULL, *buf; + bfd_byte *ehbuf = NULL, *buf, *end; bfd_byte *last_fde; - struct eh_cie_fde *ent, *this_inf; + struct eh_cie_fde *this_inf; unsigned int hdr_length, hdr_id; struct extended_cie { - struct cie cie; - unsigned int offset; - unsigned int usage_count; - unsigned int entry; + struct cie *cie; + struct eh_cie_fde *local_cie; } *ecies = NULL, *ecie; - unsigned int ecie_count = 0, ecie_alloced = 0; - struct cie *cie; + unsigned int ecie_count; + struct cie *cie, *local_cies = NULL, tmp_cie; struct elf_link_hash_table *htab; struct eh_frame_hdr_info *hdr_info; struct eh_frame_sec_info *sec_info = NULL; - unsigned int offset; unsigned int ptr_size; - unsigned int entry_alloced; + unsigned int num_cies; + unsigned int num_entries; + + htab = elf_hash_table (info); + hdr_info = &htab->eh_info; + if (hdr_info->parsed_eh_frames) + return; if (sec->size == 0) { /* This file does not contain .eh_frame information. */ - return FALSE; + return; } if (bfd_is_abs_section (sec->output_section)) { /* At least one of the sections is being discarded from the link, so we should just ignore them. */ - return FALSE; + return; } - htab = elf_hash_table (info); - hdr_info = &htab->eh_info; - - if (hdr_info->cies == NULL && !info->relocatable) - hdr_info->cies = htab_try_create (1, cie_hash, cie_eq, free); - /* Read the frame unwind information from abfd. */ REQUIRE (bfd_malloc_and_get_section (abfd, sec, &ehbuf)); @@ -497,7 +504,7 @@ _bfd_elf_discard_section_eh_frame { /* Empty .eh_frame section. */ free (ehbuf); - return FALSE; + return; } /* If .eh_frame section size doesn't fit into int, we cannot handle @@ -508,12 +515,47 @@ _bfd_elf_discard_section_eh_frame ->elf_backend_eh_frame_address_size (abfd, sec)); REQUIRE (ptr_size != 0); + /* Go through the section contents and work out how many FDEs and + CIEs there are. */ buf = ehbuf; + end = ehbuf + sec->size; + num_cies = 0; + num_entries = 0; + while (buf != end) + { + num_entries++; + + /* Read the length of the entry. */ + REQUIRE (skip_bytes (&buf, end, 4)); + hdr_length = bfd_get_32 (abfd, buf - 4); + + /* 64-bit .eh_frame is not supported. */ + REQUIRE (hdr_length != 0xffffffff); + if (hdr_length == 0) + break; + + REQUIRE (skip_bytes (&buf, end, 4)); + hdr_id = bfd_get_32 (abfd, buf - 4); + if (hdr_id == 0) + num_cies++; + + REQUIRE (skip_bytes (&buf, end, hdr_length - 4)); + } + sec_info = bfd_zmalloc (sizeof (struct eh_frame_sec_info) - + 99 * sizeof (struct eh_cie_fde)); + + (num_entries - 1) * sizeof (struct eh_cie_fde)); REQUIRE (sec_info); - entry_alloced = 100; + ecies = bfd_zmalloc (num_cies * sizeof (*ecies)); + REQUIRE (ecies); + + /* If we're not merging CIE entries (such as for a relocatable link), + we need to have a "struct cie" for each CIE in this section. */ + if (hdr_info->cies == NULL) + { + local_cies = bfd_zmalloc (num_cies * sizeof (*local_cies)); + REQUIRE (local_cies); + } #define ENSURE_NO_RELOCS(buf) \ REQUIRE (!(cookie->rel < cookie->relend \ @@ -533,39 +575,22 @@ _bfd_elf_discard_section_eh_frame == (bfd_size_type) ((buf) - ehbuf))) \ ? cookie->rel : NULL) - for (;;) + buf = ehbuf; + ecie_count = 0; + while ((bfd_size_type) (buf - ehbuf) != sec->size) { char *aug; - bfd_byte *start, *end, *insns, *insns_end; + bfd_byte *start, *insns, *insns_end; bfd_size_type length; unsigned int set_loc_count; - if (sec_info->count == entry_alloced) - { - sec_info = bfd_realloc (sec_info, - sizeof (struct eh_frame_sec_info) - + ((entry_alloced + 99) - * sizeof (struct eh_cie_fde))); - REQUIRE (sec_info); - - memset (&sec_info->entry[entry_alloced], 0, - 100 * sizeof (struct eh_cie_fde)); - entry_alloced += 100; - } - this_inf = sec_info->entry + sec_info->count; last_fde = buf; - if ((bfd_size_type) (buf - ehbuf) == sec->size) - break; - /* Read the length of the entry. */ REQUIRE (skip_bytes (&buf, ehbuf + sec->size, 4)); hdr_length = bfd_get_32 (abfd, buf - 4); - /* 64-bit .eh_frame is not supported. */ - REQUIRE (hdr_length != 0xffffffff); - /* The CIE/FDE must be fully contained in this input section. */ REQUIRE ((bfd_size_type) (buf - ehbuf) + hdr_length <= sec->size); end = buf + hdr_length; @@ -594,19 +619,19 @@ _bfd_elf_discard_section_eh_frame /* CIE */ this_inf->cie = 1; - if (ecie_count == ecie_alloced) + /* If we're merging CIEs, construct the struct cie in TMP_CIE; + we'll enter it into the global pool later. Otherwise point + CIE to one of the section-local cie structures. */ + if (local_cies) + cie = local_cies + ecie_count; + else { - ecies = bfd_realloc (ecies, - (ecie_alloced + 20) * sizeof (*ecies)); - REQUIRE (ecies); - memset (&ecies[ecie_alloced], 0, 20 * sizeof (*ecies)); - ecie_alloced += 20; + cie = &tmp_cie; + memset (cie, 0, sizeof (*cie)); } - - cie = &ecies[ecie_count].cie; - ecies[ecie_count].offset = this_inf->offset; - ecies[ecie_count++].entry = sec_info->count; + cie->cie_inf = this_inf; cie->length = hdr_length; + cie->output_sec = sec->output_section; start = buf; REQUIRE (read_byte (&buf, end, &cie->version)); @@ -788,48 +813,29 @@ _bfd_elf_discard_section_eh_frame insns = buf; buf += initial_insn_length; ENSURE_NO_RELOCS (buf); + + this_inf->make_relative = cie->make_relative; + this_inf->make_lsda_relative = cie->make_lsda_relative; + this_inf->per_encoding_relative + = (cie->per_encoding & 0x70) == DW_EH_PE_pcrel; } else { /* Find the corresponding CIE. */ unsigned int cie_offset = this_inf->offset + 4 - hdr_id; for (ecie = ecies; ecie < ecies + ecie_count; ++ecie) - if (cie_offset == ecie->offset) + if (cie_offset == ecie->local_cie->offset) break; /* Ensure this FDE references one of the CIEs in this input section. */ REQUIRE (ecie != ecies + ecie_count); - cie = &ecie->cie; + cie = ecie->cie; + this_inf->u.fde.cie_inf = ecie->local_cie; ENSURE_NO_RELOCS (buf); REQUIRE (GET_RELOC (buf)); - if ((*reloc_symbol_deleted_p) (buf - ehbuf, cookie)) - /* This is a FDE against a discarded section. It should - be deleted. */ - this_inf->removed = 1; - else - { - if (info->shared - && (((cie->fde_encoding & 0xf0) == DW_EH_PE_absptr - && cie->make_relative == 0) - || (cie->fde_encoding & 0xf0) == DW_EH_PE_aligned)) - { - /* If a shared library uses absolute pointers - which we cannot turn into PC relative, - don't create the binary search table, - since it is affected by runtime relocations. */ - hdr_info->table = FALSE; - (*info->callbacks->einfo) - (_("%P: fde encoding in %B(%A) prevents .eh_frame_hdr" - " table being created.\n"), abfd, sec); - } - ecie->usage_count++; - hdr_info->fde_count++; - this_inf->u.fde.cie_inf = (void *) (ecie - ecies); - } - /* Skip the initial location and address range. */ start = buf; length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); @@ -901,90 +907,155 @@ _bfd_elf_discard_section_eh_frame } } + this_inf->removed = 1; this_inf->fde_encoding = cie->fde_encoding; this_inf->lsda_encoding = cie->lsda_encoding; + if (this_inf->cie) + { + /* We have now finished constructing the struct cie. */ + if (hdr_info->cies != NULL) + { + /* See if we can merge this CIE with an earlier one. */ + void **loc; + + cie_compute_hash (cie); + loc = htab_find_slot_with_hash (hdr_info->cies, cie, + cie->hash, INSERT); + REQUIRE (loc); + if (*loc == HTAB_EMPTY_ENTRY) + { + *loc = malloc (sizeof (struct cie)); + REQUIRE (*loc); + memcpy (*loc, cie, sizeof (struct cie)); + } + cie = (struct cie *) *loc; + } + this_inf->u.cie.merged = cie->cie_inf; + ecies[ecie_count].cie = cie; + ecies[ecie_count++].local_cie = this_inf; + } sec_info->count++; } + BFD_ASSERT (sec_info->count == num_entries); + BFD_ASSERT (ecie_count == num_cies); elf_section_data (sec)->sec_info = sec_info; sec->sec_info_type = ELF_INFO_TYPE_EH_FRAME; + goto success; - /* Look at all CIEs in this section and determine which can be - removed as unused, which can be merged with previous duplicate - CIEs and which need to be kept. */ - for (ecie = ecies; ecie < ecies + ecie_count; ++ecie) - { - if (ecie->usage_count == 0) - { - sec_info->entry[ecie->entry].removed = 1; - continue; - } - ecie->cie.output_sec = sec->output_section; - ecie->cie.cie_inf = sec_info->entry + ecie->entry; - cie_compute_hash (&ecie->cie); - if (hdr_info->cies != NULL) - { - void **loc = htab_find_slot_with_hash (hdr_info->cies, &ecie->cie, - ecie->cie.hash, INSERT); - if (loc != NULL) - { - if (*loc != HTAB_EMPTY_ENTRY) - { - sec_info->entry[ecie->entry].removed = 1; - ecie->cie.cie_inf = ((struct cie *) *loc)->cie_inf; - continue; - } + free_no_table: + (*info->callbacks->einfo) + (_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"), + abfd, sec); + hdr_info->table = FALSE; + if (sec_info) + free (sec_info); + success: + if (ehbuf) + free (ehbuf); + if (ecies) + free (ecies); + if (local_cies) + free (local_cies); +#undef REQUIRE +} - *loc = malloc (sizeof (struct cie)); - if (*loc == NULL) - *loc = HTAB_DELETED_ENTRY; - else - memcpy (*loc, &ecie->cie, sizeof (struct cie)); - } - } - ecie->cie.cie_inf->make_relative = ecie->cie.make_relative; - ecie->cie.cie_inf->make_lsda_relative = ecie->cie.make_lsda_relative; - ecie->cie.cie_inf->per_encoding_relative - = (ecie->cie.per_encoding & 0x70) == DW_EH_PE_pcrel; +/* Finish a pass over all .eh_frame sections. */ + +void +_bfd_elf_end_eh_frame_parsing (struct bfd_link_info *info) +{ + struct eh_frame_hdr_info *hdr_info; + + hdr_info = &elf_hash_table (info)->eh_info; + if (hdr_info->cies != NULL) + { + htab_delete (hdr_info->cies); + hdr_info->cies = NULL; } + hdr_info->parsed_eh_frames = TRUE; +} - /* Ok, now we can assign new offsets. */ - offset = 0; +/* This function is called for each input file before the .eh_frame + section is relocated. It discards duplicate CIEs and FDEs for discarded + functions. The function returns TRUE iff any entries have been + deleted. */ + +bfd_boolean +_bfd_elf_discard_section_eh_frame + (bfd *abfd, struct bfd_link_info *info, asection *sec, + bfd_boolean (*reloc_symbol_deleted_p) (bfd_vma, void *), + struct elf_reloc_cookie *cookie) +{ + struct eh_cie_fde *ent, *cie, *merged; + struct eh_frame_sec_info *sec_info; + struct eh_frame_hdr_info *hdr_info; + unsigned int ptr_size, offset; + + sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; + if (sec_info == NULL) + return FALSE; + + hdr_info = &elf_hash_table (info)->eh_info; for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) - if (!ent->removed) + if (!ent->cie) { - if (!ent->cie) + cookie->rel = cookie->rels + ent->reloc_index; + BFD_ASSERT (cookie->rel < cookie->relend + && cookie->rel->r_offset == ent->offset + 8); + if (!(*reloc_symbol_deleted_p) (ent->offset + 8, cookie)) { - ecie = ecies + (bfd_hostptr_t) ent->u.fde.cie_inf; - ent->u.fde.cie_inf = ecie->cie.cie_inf; + if (info->shared + && (((ent->fde_encoding & 0xf0) == DW_EH_PE_absptr + && ent->u.fde.cie_inf->make_relative == 0) + || (ent->fde_encoding & 0xf0) == DW_EH_PE_aligned)) + { + /* If a shared library uses absolute pointers + which we cannot turn into PC relative, + don't create the binary search table, + since it is affected by runtime relocations. */ + hdr_info->table = FALSE; + (*info->callbacks->einfo) + (_("%P: fde encoding in %B(%A) prevents .eh_frame_hdr" + " table being created.\n"), abfd, sec); + } + ent->removed = 0; + hdr_info->fde_count++; + + cie = ent->u.fde.cie_inf; + if (cie->removed) + { + merged = cie->u.cie.merged; + if (!merged->removed) + /* We have decided to keep the group representative. */ + ent->u.fde.cie_inf = merged; + else if (merged->u.cie.merged != merged) + /* We didn't keep the original group representative, + but we did keep an alternative. */ + ent->u.fde.cie_inf = merged->u.cie.merged; + else + { + /* Make the local CIE represent the merged group. */ + merged->u.cie.merged = cie; + cie->removed = 0; + } + } } + } + + ptr_size = (get_elf_backend_data (sec->owner) + ->elf_backend_eh_frame_address_size (sec->owner, sec)); + offset = 0; + for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) + if (!ent->removed) + { ent->new_offset = offset; offset += size_of_output_cie_fde (ent, ptr_size); } - /* Resize the sec as needed. */ sec->rawsize = sec->size; sec->size = offset; - - free (ehbuf); - if (ecies) - free (ecies); return offset != sec->rawsize; - -free_no_table: - (*info->callbacks->einfo) - (_("%P: error in %B(%A); no .eh_frame_hdr table will be created.\n"), - abfd, sec); - if (ehbuf) - free (ehbuf); - if (sec_info) - free (sec_info); - if (ecies) - free (ecies); - hdr_info->table = FALSE; - return FALSE; - -#undef REQUIRE } /* This function is called for .eh_frame_hdr section after @@ -1001,12 +1072,6 @@ _bfd_elf_discard_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) htab = elf_hash_table (info); hdr_info = &htab->eh_info; - if (hdr_info->cies != NULL) - { - htab_delete (hdr_info->cies); - hdr_info->cies = NULL; - } - sec = hdr_info->hdr_sec; if (sec == NULL) return FALSE; diff --git a/bfd/elflink.c b/bfd/elflink.c index a73f6c8..4201e28 100644 --- a/bfd/elflink.c +++ b/bfd/elflink.c @@ -11894,6 +11894,7 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info) || !is_elf_hash_table (info->hash)) return FALSE; + _bfd_elf_begin_eh_frame_parsing (info); for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) { if (bfd_get_flavour (abfd) != bfd_target_elf_flavour) @@ -11944,6 +11945,7 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info) if (eh != NULL && init_reloc_cookie_rels (&cookie, info, abfd, eh)) { + _bfd_elf_parse_eh_frame (abfd, info, eh, &cookie); if (_bfd_elf_discard_section_eh_frame (abfd, info, eh, bfd_elf_reloc_symbol_deleted_p, &cookie)) @@ -11957,6 +11959,7 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info) fini_reloc_cookie (&cookie, abfd); } + _bfd_elf_end_eh_frame_parsing (info); if (info->eh_frame_hdr && !info->relocatable |