diff options
Diffstat (limited to 'binutils-2.25/bfd/elf-eh-frame.c')
| -rw-r--r-- | binutils-2.25/bfd/elf-eh-frame.c | 1883 |
1 files changed, 1883 insertions, 0 deletions
diff --git a/binutils-2.25/bfd/elf-eh-frame.c b/binutils-2.25/bfd/elf-eh-frame.c new file mode 100644 index 00000000..832a9919 --- /dev/null +++ b/binutils-2.25/bfd/elf-eh-frame.c @@ -0,0 +1,1883 @@ +/* .eh_frame section optimization. + Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, + 2012 Free Software Foundation, Inc. + Written by Jakub Jelinek <jakub@redhat.com>. + + This file is part of BFD, the Binary File Descriptor library. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, + MA 02110-1301, USA. */ + +#include "sysdep.h" +#include "bfd.h" +#include "libbfd.h" +#include "elf-bfd.h" +#include "dwarf2.h" + +#define EH_FRAME_HDR_SIZE 8 + +struct cie +{ + unsigned int length; + unsigned int hash; + unsigned char version; + unsigned char local_personality; + char augmentation[20]; + bfd_vma code_align; + bfd_signed_vma data_align; + bfd_vma ra_column; + bfd_vma augmentation_size; + union { + struct elf_link_hash_entry *h; + bfd_vma val; + unsigned int reloc_index; + } personality; + asection *output_sec; + struct eh_cie_fde *cie_inf; + unsigned char per_encoding; + unsigned char lsda_encoding; + unsigned char fde_encoding; + unsigned char initial_insn_length; + unsigned char can_make_lsda_relative; + unsigned char initial_instructions[50]; +}; + + + +/* If *ITER hasn't reached END yet, read the next byte into *RESULT and + move onto the next byte. Return true on success. */ + +static inline bfd_boolean +read_byte (bfd_byte **iter, bfd_byte *end, unsigned char *result) +{ + if (*iter >= end) + return FALSE; + *result = *((*iter)++); + return TRUE; +} + +/* Move *ITER over LENGTH bytes, or up to END, whichever is closer. + Return true it was possible to move LENGTH bytes. */ + +static inline bfd_boolean +skip_bytes (bfd_byte **iter, bfd_byte *end, bfd_size_type length) +{ + if ((bfd_size_type) (end - *iter) < length) + { + *iter = end; + return FALSE; + } + *iter += length; + return TRUE; +} + +/* Move *ITER over an leb128, stopping at END. Return true if the end + of the leb128 was found. */ + +static bfd_boolean +skip_leb128 (bfd_byte **iter, bfd_byte *end) +{ + unsigned char byte; + do + if (!read_byte (iter, end, &byte)) + return FALSE; + while (byte & 0x80); + return TRUE; +} + +/* Like skip_leb128, but treat the leb128 as an unsigned value and + store it in *VALUE. */ + +static bfd_boolean +read_uleb128 (bfd_byte **iter, bfd_byte *end, bfd_vma *value) +{ + bfd_byte *start, *p; + + start = *iter; + if (!skip_leb128 (iter, end)) + return FALSE; + + p = *iter; + *value = *--p; + while (p > start) + *value = (*value << 7) | (*--p & 0x7f); + + return TRUE; +} + +/* Like read_uleb128, but for signed values. */ + +static bfd_boolean +read_sleb128 (bfd_byte **iter, bfd_byte *end, bfd_signed_vma *value) +{ + bfd_byte *start, *p; + + start = *iter; + if (!skip_leb128 (iter, end)) + return FALSE; + + p = *iter; + *value = ((*--p & 0x7f) ^ 0x40) - 0x40; + while (p > start) + *value = (*value << 7) | (*--p & 0x7f); + + return TRUE; +} + +/* Return 0 if either encoding is variable width, or not yet known to bfd. */ + +static +int get_DW_EH_PE_width (int encoding, int ptr_size) +{ + /* DW_EH_PE_ values of 0x60 and 0x70 weren't defined at the time .eh_frame + was added to bfd. */ + if ((encoding & 0x60) == 0x60) + return 0; + + switch (encoding & 7) + { + case DW_EH_PE_udata2: return 2; + case DW_EH_PE_udata4: return 4; + case DW_EH_PE_udata8: return 8; + case DW_EH_PE_absptr: return ptr_size; + default: + break; + } + + return 0; +} + +#define get_DW_EH_PE_signed(encoding) (((encoding) & DW_EH_PE_signed) != 0) + +/* Read a width sized value from memory. */ + +static bfd_vma +read_value (bfd *abfd, bfd_byte *buf, int width, int is_signed) +{ + bfd_vma value; + + switch (width) + { + case 2: + if (is_signed) + value = bfd_get_signed_16 (abfd, buf); + else + value = bfd_get_16 (abfd, buf); + break; + case 4: + if (is_signed) + value = bfd_get_signed_32 (abfd, buf); + else + value = bfd_get_32 (abfd, buf); + break; + case 8: + if (is_signed) + value = bfd_get_signed_64 (abfd, buf); + else + value = bfd_get_64 (abfd, buf); + break; + default: + BFD_FAIL (); + return 0; + } + + return value; +} + +/* Store a width sized value to memory. */ + +static void +write_value (bfd *abfd, bfd_byte *buf, bfd_vma value, int width) +{ + switch (width) + { + case 2: bfd_put_16 (abfd, value, buf); break; + case 4: bfd_put_32 (abfd, value, buf); break; + case 8: bfd_put_64 (abfd, value, buf); break; + default: BFD_FAIL (); + } +} + +/* Return one if C1 and C2 CIEs can be merged. */ + +static int +cie_eq (const void *e1, const void *e2) +{ + const struct cie *c1 = (const struct cie *) e1; + const struct cie *c2 = (const struct cie *) e2; + + if (c1->hash == c2->hash + && c1->length == c2->length + && c1->version == c2->version + && c1->local_personality == c2->local_personality + && strcmp (c1->augmentation, c2->augmentation) == 0 + && strcmp (c1->augmentation, "eh") != 0 + && c1->code_align == c2->code_align + && c1->data_align == c2->data_align + && c1->ra_column == c2->ra_column + && c1->augmentation_size == c2->augmentation_size + && memcmp (&c1->personality, &c2->personality, + sizeof (c1->personality)) == 0 + && c1->output_sec == c2->output_sec + && c1->per_encoding == c2->per_encoding + && c1->lsda_encoding == c2->lsda_encoding + && c1->fde_encoding == c2->fde_encoding + && c1->initial_insn_length == c2->initial_insn_length + && memcmp (c1->initial_instructions, + c2->initial_instructions, + c1->initial_insn_length) == 0) + return 1; + + return 0; +} + +static hashval_t +cie_hash (const void *e) +{ + const struct cie *c = (const struct cie *) e; + return c->hash; +} + +static hashval_t +cie_compute_hash (struct cie *c) +{ + hashval_t h = 0; + h = iterative_hash_object (c->length, h); + h = iterative_hash_object (c->version, h); + h = iterative_hash (c->augmentation, strlen (c->augmentation) + 1, h); + h = iterative_hash_object (c->code_align, h); + h = iterative_hash_object (c->data_align, h); + h = iterative_hash_object (c->ra_column, h); + h = iterative_hash_object (c->augmentation_size, h); + h = iterative_hash_object (c->personality, h); + h = iterative_hash_object (c->output_sec, h); + h = iterative_hash_object (c->per_encoding, h); + h = iterative_hash_object (c->lsda_encoding, h); + h = iterative_hash_object (c->fde_encoding, h); + h = iterative_hash_object (c->initial_insn_length, h); + h = iterative_hash (c->initial_instructions, c->initial_insn_length, h); + c->hash = h; + return h; +} + +/* Return the number of extra bytes that we'll be inserting into + ENTRY's augmentation string. */ + +static INLINE unsigned int +extra_augmentation_string_bytes (struct eh_cie_fde *entry) +{ + unsigned int size = 0; + if (entry->cie) + { + if (entry->add_augmentation_size) + size++; + if (entry->u.cie.add_fde_encoding) + size++; + } + return size; +} + +/* Likewise ENTRY's augmentation data. */ + +static INLINE unsigned int +extra_augmentation_data_bytes (struct eh_cie_fde *entry) +{ + unsigned int size = 0; + if (entry->add_augmentation_size) + size++; + if (entry->cie && entry->u.cie.add_fde_encoding) + size++; + return size; +} + +/* Return the size that ENTRY will have in the output. ALIGNMENT is the + required alignment of ENTRY in bytes. */ + +static unsigned int +size_of_output_cie_fde (struct eh_cie_fde *entry, unsigned int alignment) +{ + if (entry->removed) + return 0; + if (entry->size == 4) + return 4; + return (entry->size + + extra_augmentation_string_bytes (entry) + + extra_augmentation_data_bytes (entry) + + alignment - 1) & -alignment; +} + +/* Assume that the bytes between *ITER and END are CFA instructions. + Try to move *ITER past the first instruction and return true on + success. ENCODED_PTR_WIDTH gives the width of pointer entries. */ + +static bfd_boolean +skip_cfa_op (bfd_byte **iter, bfd_byte *end, unsigned int encoded_ptr_width) +{ + bfd_byte op; + bfd_vma length; + + if (!read_byte (iter, end, &op)) + return FALSE; + + switch (op & 0xc0 ? op & 0xc0 : op) + { + case DW_CFA_nop: + case DW_CFA_advance_loc: + case DW_CFA_restore: + case DW_CFA_remember_state: + case DW_CFA_restore_state: + case DW_CFA_GNU_window_save: + /* No arguments. */ + return TRUE; + + case DW_CFA_offset: + case DW_CFA_restore_extended: + case DW_CFA_undefined: + case DW_CFA_same_value: + case DW_CFA_def_cfa_register: + case DW_CFA_def_cfa_offset: + case DW_CFA_def_cfa_offset_sf: + case DW_CFA_GNU_args_size: + /* One leb128 argument. */ + return skip_leb128 (iter, end); + + case DW_CFA_val_offset: + case DW_CFA_val_offset_sf: + case DW_CFA_offset_extended: + case DW_CFA_register: + case DW_CFA_def_cfa: + case DW_CFA_offset_extended_sf: + case DW_CFA_GNU_negative_offset_extended: + case DW_CFA_def_cfa_sf: + /* Two leb128 arguments. */ + return (skip_leb128 (iter, end) + && skip_leb128 (iter, end)); + + case DW_CFA_def_cfa_expression: + /* A variable-length argument. */ + return (read_uleb128 (iter, end, &length) + && skip_bytes (iter, end, length)); + + case DW_CFA_expression: + case DW_CFA_val_expression: + /* A leb128 followed by a variable-length argument. */ + return (skip_leb128 (iter, end) + && read_uleb128 (iter, end, &length) + && skip_bytes (iter, end, length)); + + case DW_CFA_set_loc: + return skip_bytes (iter, end, encoded_ptr_width); + + case DW_CFA_advance_loc1: + return skip_bytes (iter, end, 1); + + case DW_CFA_advance_loc2: + return skip_bytes (iter, end, 2); + + case DW_CFA_advance_loc4: + return skip_bytes (iter, end, 4); + + case DW_CFA_MIPS_advance_loc8: + return skip_bytes (iter, end, 8); + + default: + return FALSE; + } +} + +/* Try to interpret the bytes between BUF and END as CFA instructions. + If every byte makes sense, return a pointer to the first DW_CFA_nop + padding byte, or END if there is no padding. Return null otherwise. + ENCODED_PTR_WIDTH is as for skip_cfa_op. */ + +static bfd_byte * +skip_non_nops (bfd_byte *buf, bfd_byte *end, unsigned int encoded_ptr_width, + unsigned int *set_loc_count) +{ + bfd_byte *last; + + last = buf; + while (buf < end) + if (*buf == DW_CFA_nop) + buf++; + else + { + if (*buf == DW_CFA_set_loc) + ++*set_loc_count; + if (!skip_cfa_op (&buf, end, encoded_ptr_width)) + return 0; + last = buf; + } + return last; +} + +/* Convert absolute encoding ENCODING into PC-relative form. + SIZE is the size of a pointer. */ + +static unsigned char +make_pc_relative (unsigned char encoding, unsigned int ptr_size) +{ + if ((encoding & 0x7f) == DW_EH_PE_absptr) + switch (ptr_size) + { + case 2: + encoding |= DW_EH_PE_sdata2; + break; + case 4: + encoding |= DW_EH_PE_sdata4; + break; + case 8: + encoding |= DW_EH_PE_sdata8; + break; + } + return encoding | DW_EH_PE_pcrel; +} + +/* Called before calling _bfd_elf_parse_eh_frame on every input bfd's + .eh_frame section. */ + +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; + hdr_info->merge_cies = !info->relocatable; +} + +/* 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 \ + if (!(COND)) \ + goto free_no_table; \ + while (0) + + bfd_byte *ehbuf = NULL, *buf, *end; + bfd_byte *last_fde; + struct eh_cie_fde *this_inf; + unsigned int hdr_length, hdr_id; + unsigned int cie_count; + struct cie *cie, *local_cies = NULL; + struct elf_link_hash_table *htab; + struct eh_frame_hdr_info *hdr_info; + struct eh_frame_sec_info *sec_info = NULL; + unsigned int ptr_size; + unsigned int num_cies; + unsigned int num_entries; + elf_gc_mark_hook_fn gc_mark_hook; + + htab = elf_hash_table (info); + hdr_info = &htab->eh_info; + if (hdr_info->parsed_eh_frames) + return; + + if (sec->size == 0 + || sec->sec_info_type != SEC_INFO_TYPE_NONE) + { + /* This file does not contain .eh_frame information. */ + 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; + } + + /* Read the frame unwind information from abfd. */ + + REQUIRE (bfd_malloc_and_get_section (abfd, sec, &ehbuf)); + + if (sec->size >= 4 + && bfd_get_32 (abfd, ehbuf) == 0 + && cookie->rel == cookie->relend) + { + /* Empty .eh_frame section. */ + free (ehbuf); + return; + } + + /* If .eh_frame section size doesn't fit into int, we cannot handle + it (it would need to use 64-bit .eh_frame format anyway). */ + REQUIRE (sec->size == (unsigned int) sec->size); + + ptr_size = (get_elf_backend_data (abfd) + ->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 = (struct eh_frame_sec_info *) + bfd_zmalloc (sizeof (struct eh_frame_sec_info) + + (num_entries - 1) * sizeof (struct eh_cie_fde)); + REQUIRE (sec_info); + + /* We need to have a "struct cie" for each CIE in this section. */ + local_cies = (struct cie *) bfd_zmalloc (num_cies * sizeof (*local_cies)); + REQUIRE (local_cies); + + /* FIXME: octets_per_byte. */ +#define ENSURE_NO_RELOCS(buf) \ + REQUIRE (!(cookie->rel < cookie->relend \ + && (cookie->rel->r_offset \ + < (bfd_size_type) ((buf) - ehbuf)) \ + && cookie->rel->r_info != 0)) + + /* FIXME: octets_per_byte. */ +#define SKIP_RELOCS(buf) \ + while (cookie->rel < cookie->relend \ + && (cookie->rel->r_offset \ + < (bfd_size_type) ((buf) - ehbuf))) \ + cookie->rel++ + + /* FIXME: octets_per_byte. */ +#define GET_RELOC(buf) \ + ((cookie->rel < cookie->relend \ + && (cookie->rel->r_offset \ + == (bfd_size_type) ((buf) - ehbuf))) \ + ? cookie->rel : NULL) + + buf = ehbuf; + cie_count = 0; + gc_mark_hook = get_elf_backend_data (abfd)->gc_mark_hook; + while ((bfd_size_type) (buf - ehbuf) != sec->size) + { + char *aug; + bfd_byte *start, *insns, *insns_end; + bfd_size_type length; + unsigned int set_loc_count; + + this_inf = sec_info->entry + sec_info->count; + last_fde = buf; + + /* Read the length of the entry. */ + REQUIRE (skip_bytes (&buf, ehbuf + sec->size, 4)); + hdr_length = bfd_get_32 (abfd, buf - 4); + + /* 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; + + this_inf->offset = last_fde - ehbuf; + this_inf->size = 4 + hdr_length; + this_inf->reloc_index = cookie->rel - cookie->rels; + + if (hdr_length == 0) + { + /* A zero-length CIE should only be found at the end of + the section. */ + REQUIRE ((bfd_size_type) (buf - ehbuf) == sec->size); + ENSURE_NO_RELOCS (buf); + sec_info->count++; + break; + } + + REQUIRE (skip_bytes (&buf, end, 4)); + hdr_id = bfd_get_32 (abfd, buf - 4); + + if (hdr_id == 0) + { + unsigned int initial_insn_length; + + /* CIE */ + this_inf->cie = 1; + + /* Point CIE to one of the section-local cie structures. */ + cie = local_cies + cie_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)); + + /* Cannot handle unknown versions. */ + REQUIRE (cie->version == 1 + || cie->version == 3 + || cie->version == 4); + REQUIRE (strlen ((char *) buf) < sizeof (cie->augmentation)); + + strcpy (cie->augmentation, (char *) buf); + buf = (bfd_byte *) strchr ((char *) buf, '\0') + 1; + ENSURE_NO_RELOCS (buf); + if (buf[0] == 'e' && buf[1] == 'h') + { + /* GCC < 3.0 .eh_frame CIE */ + /* We cannot merge "eh" CIEs because __EXCEPTION_TABLE__ + is private to each CIE, so we don't need it for anything. + Just skip it. */ + REQUIRE (skip_bytes (&buf, end, ptr_size)); + SKIP_RELOCS (buf); + } + if (cie->version >= 4) + { + REQUIRE (buf + 1 < end); + REQUIRE (buf[0] == ptr_size); + REQUIRE (buf[1] == 0); + buf += 2; + } + REQUIRE (read_uleb128 (&buf, end, &cie->code_align)); + REQUIRE (read_sleb128 (&buf, end, &cie->data_align)); + if (cie->version == 1) + { + REQUIRE (buf < end); + cie->ra_column = *buf++; + } + else + REQUIRE (read_uleb128 (&buf, end, &cie->ra_column)); + ENSURE_NO_RELOCS (buf); + cie->lsda_encoding = DW_EH_PE_omit; + cie->fde_encoding = DW_EH_PE_omit; + cie->per_encoding = DW_EH_PE_omit; + aug = cie->augmentation; + if (aug[0] != 'e' || aug[1] != 'h') + { + if (*aug == 'z') + { + aug++; + REQUIRE (read_uleb128 (&buf, end, &cie->augmentation_size)); + ENSURE_NO_RELOCS (buf); + } + + while (*aug != '\0') + switch (*aug++) + { + case 'L': + REQUIRE (read_byte (&buf, end, &cie->lsda_encoding)); + ENSURE_NO_RELOCS (buf); + REQUIRE (get_DW_EH_PE_width (cie->lsda_encoding, ptr_size)); + break; + case 'R': + REQUIRE (read_byte (&buf, end, &cie->fde_encoding)); + ENSURE_NO_RELOCS (buf); + REQUIRE (get_DW_EH_PE_width (cie->fde_encoding, ptr_size)); + break; + case 'S': + break; + case 'P': + { + int per_width; + + REQUIRE (read_byte (&buf, end, &cie->per_encoding)); + per_width = get_DW_EH_PE_width (cie->per_encoding, + ptr_size); + REQUIRE (per_width); + if ((cie->per_encoding & 0x70) == DW_EH_PE_aligned) + { + length = -(buf - ehbuf) & (per_width - 1); + REQUIRE (skip_bytes (&buf, end, length)); + } + this_inf->u.cie.personality_offset = buf - start; + ENSURE_NO_RELOCS (buf); + /* Ensure we have a reloc here. */ + REQUIRE (GET_RELOC (buf)); + cie->personality.reloc_index + = cookie->rel - cookie->rels; + /* Cope with MIPS-style composite relocations. */ + do + cookie->rel++; + while (GET_RELOC (buf) != NULL); + REQUIRE (skip_bytes (&buf, end, per_width)); + } + break; + default: + /* Unrecognized augmentation. Better bail out. */ + goto free_no_table; + } + } + + /* For shared libraries, try to get rid of as many RELATIVE relocs + as possible. */ + if (info->shared + && (get_elf_backend_data (abfd) + ->elf_backend_can_make_relative_eh_frame + (abfd, info, sec))) + { + if ((cie->fde_encoding & 0x70) == DW_EH_PE_absptr) + this_inf->make_relative = 1; + /* If the CIE doesn't already have an 'R' entry, it's fairly + easy to add one, provided that there's no aligned data + after the augmentation string. */ + else if (cie->fde_encoding == DW_EH_PE_omit + && (cie->per_encoding & 0x70) != DW_EH_PE_aligned) + { + if (*cie->augmentation == 0) + this_inf->add_augmentation_size = 1; + this_inf->u.cie.add_fde_encoding = 1; + this_inf->make_relative = 1; + } + + if ((cie->lsda_encoding & 0x70) == DW_EH_PE_absptr) + cie->can_make_lsda_relative = 1; + } + + /* If FDE encoding was not specified, it defaults to + DW_EH_absptr. */ + if (cie->fde_encoding == DW_EH_PE_omit) + cie->fde_encoding = DW_EH_PE_absptr; + + initial_insn_length = end - buf; + if (initial_insn_length <= sizeof (cie->initial_instructions)) + { + cie->initial_insn_length = initial_insn_length; + memcpy (cie->initial_instructions, buf, initial_insn_length); + } + insns = buf; + buf += initial_insn_length; + ENSURE_NO_RELOCS (buf); + + if (hdr_info->merge_cies) + this_inf->u.cie.u.full_cie = cie; + this_inf->u.cie.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 (cie = local_cies; cie < local_cies + cie_count; cie++) + if (cie_offset == cie->cie_inf->offset) + break; + + /* Ensure this FDE references one of the CIEs in this input + section. */ + REQUIRE (cie != local_cies + cie_count); + this_inf->u.fde.cie_inf = cie->cie_inf; + this_inf->make_relative = cie->cie_inf->make_relative; + this_inf->add_augmentation_size + = cie->cie_inf->add_augmentation_size; + + ENSURE_NO_RELOCS (buf); + if ((sec->flags & SEC_LINKER_CREATED) == 0 || cookie->rels != NULL) + { + asection *rsec; + + REQUIRE (GET_RELOC (buf)); + + /* Chain together the FDEs for each section. */ + rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook, cookie); + /* RSEC will be NULL if FDE was cleared out as it was belonging to + a discarded SHT_GROUP. */ + if (rsec) + { + REQUIRE (rsec->owner == abfd); + this_inf->u.fde.next_for_section = elf_fde_list (rsec); + elf_fde_list (rsec) = this_inf; + } + } + + /* Skip the initial location and address range. */ + start = buf; + length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); + REQUIRE (skip_bytes (&buf, end, 2 * length)); + + /* Skip the augmentation size, if present. */ + if (cie->augmentation[0] == 'z') + REQUIRE (read_uleb128 (&buf, end, &length)); + else + length = 0; + + /* Of the supported augmentation characters above, only 'L' + adds augmentation data to the FDE. This code would need to + be adjusted if any future augmentations do the same thing. */ + if (cie->lsda_encoding != DW_EH_PE_omit) + { + SKIP_RELOCS (buf); + if (cie->can_make_lsda_relative && GET_RELOC (buf)) + cie->cie_inf->u.cie.make_lsda_relative = 1; + this_inf->lsda_offset = buf - start; + /* If there's no 'z' augmentation, we don't know where the + CFA insns begin. Assume no padding. */ + if (cie->augmentation[0] != 'z') + length = end - buf; + } + + /* Skip over the augmentation data. */ + REQUIRE (skip_bytes (&buf, end, length)); + insns = buf; + + buf = last_fde + 4 + hdr_length; + + /* For NULL RSEC (cleared FDE belonging to a discarded section) + the relocations are commonly cleared. We do not sanity check if + all these relocations are cleared as (1) relocations to + .gcc_except_table will remain uncleared (they will get dropped + with the drop of this unused FDE) and (2) BFD already safely drops + relocations of any type to .eh_frame by + elf_section_ignore_discarded_relocs. + TODO: The .gcc_except_table entries should be also filtered as + .eh_frame entries; or GCC could rather use COMDAT for them. */ + SKIP_RELOCS (buf); + } + + /* Try to interpret the CFA instructions and find the first + padding nop. Shrink this_inf's size so that it doesn't + include the padding. */ + length = get_DW_EH_PE_width (cie->fde_encoding, ptr_size); + set_loc_count = 0; + insns_end = skip_non_nops (insns, end, length, &set_loc_count); + /* If we don't understand the CFA instructions, we can't know + what needs to be adjusted there. */ + if (insns_end == NULL + /* For the time being we don't support DW_CFA_set_loc in + CIE instructions. */ + || (set_loc_count && this_inf->cie)) + goto free_no_table; + this_inf->size -= end - insns_end; + if (insns_end != end && this_inf->cie) + { + cie->initial_insn_length -= end - insns_end; + cie->length -= end - insns_end; + } + if (set_loc_count + && ((cie->fde_encoding & 0x70) == DW_EH_PE_pcrel + || this_inf->make_relative)) + { + unsigned int cnt; + bfd_byte *p; + + this_inf->set_loc = (unsigned int *) + bfd_malloc ((set_loc_count + 1) * sizeof (unsigned int)); + REQUIRE (this_inf->set_loc); + this_inf->set_loc[0] = set_loc_count; + p = insns; + cnt = 0; + while (p < end) + { + if (*p == DW_CFA_set_loc) + this_inf->set_loc[++cnt] = p + 1 - start; + REQUIRE (skip_cfa_op (&p, end, length)); + } + } + + this_inf->removed = 1; + this_inf->fde_encoding = cie->fde_encoding; + this_inf->lsda_encoding = cie->lsda_encoding; + sec_info->count++; + } + BFD_ASSERT (sec_info->count == num_entries); + BFD_ASSERT (cie_count == num_cies); + + elf_section_data (sec)->sec_info = sec_info; + sec->sec_info_type = SEC_INFO_TYPE_EH_FRAME; + if (hdr_info->merge_cies) + { + sec_info->cies = local_cies; + local_cies = NULL; + } + goto success; + + 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 (local_cies) + free (local_cies); +#undef REQUIRE +} + +/* 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; + hdr_info->parsed_eh_frames = TRUE; +} + +/* Mark all relocations against CIE or FDE ENT, which occurs in + .eh_frame section SEC. COOKIE describes the relocations in SEC; + its "rel" field can be changed freely. */ + +static bfd_boolean +mark_entry (struct bfd_link_info *info, asection *sec, + struct eh_cie_fde *ent, elf_gc_mark_hook_fn gc_mark_hook, + struct elf_reloc_cookie *cookie) +{ + /* FIXME: octets_per_byte. */ + for (cookie->rel = cookie->rels + ent->reloc_index; + cookie->rel < cookie->relend + && cookie->rel->r_offset < ent->offset + ent->size; + cookie->rel++) + if (!_bfd_elf_gc_mark_reloc (info, sec, gc_mark_hook, cookie)) + return FALSE; + + return TRUE; +} + +/* Mark all the relocations against FDEs that relate to code in input + section SEC. The FDEs belong to .eh_frame section EH_FRAME, whose + relocations are described by COOKIE. */ + +bfd_boolean +_bfd_elf_gc_mark_fdes (struct bfd_link_info *info, asection *sec, + asection *eh_frame, elf_gc_mark_hook_fn gc_mark_hook, + struct elf_reloc_cookie *cookie) +{ + struct eh_cie_fde *fde, *cie; + + for (fde = elf_fde_list (sec); fde; fde = fde->u.fde.next_for_section) + { + if (!mark_entry (info, eh_frame, fde, gc_mark_hook, cookie)) + return FALSE; + + /* At this stage, all cie_inf fields point to local CIEs, so we + can use the same cookie to refer to them. */ + cie = fde->u.fde.cie_inf; + if (!cie->u.cie.gc_mark) + { + cie->u.cie.gc_mark = 1; + if (!mark_entry (info, eh_frame, cie, gc_mark_hook, cookie)) + return FALSE; + } + } + return TRUE; +} + +/* Input section SEC of ABFD is an .eh_frame section that contains the + CIE described by CIE_INF. Return a version of CIE_INF that is going + to be kept in the output, adding CIE_INF to the output if necessary. + + HDR_INFO is the .eh_frame_hdr information and COOKIE describes the + relocations in REL. */ + +static struct eh_cie_fde * +find_merged_cie (bfd *abfd, struct bfd_link_info *info, asection *sec, + struct eh_frame_hdr_info *hdr_info, + struct elf_reloc_cookie *cookie, + struct eh_cie_fde *cie_inf) +{ + unsigned long r_symndx; + struct cie *cie, *new_cie; + Elf_Internal_Rela *rel; + void **loc; + + /* Use CIE_INF if we have already decided to keep it. */ + if (!cie_inf->removed) + return cie_inf; + + /* If we have merged CIE_INF with another CIE, use that CIE instead. */ + if (cie_inf->u.cie.merged) + return cie_inf->u.cie.u.merged_with; + + cie = cie_inf->u.cie.u.full_cie; + + /* Assume we will need to keep CIE_INF. */ + cie_inf->removed = 0; + cie_inf->u.cie.u.sec = sec; + + /* If we are not merging CIEs, use CIE_INF. */ + if (cie == NULL) + return cie_inf; + + if (cie->per_encoding != DW_EH_PE_omit) + { + bfd_boolean per_binds_local; + + /* Work out the address of personality routine, either as an absolute + value or as a symbol. */ + rel = cookie->rels + cie->personality.reloc_index; + memset (&cie->personality, 0, sizeof (cie->personality)); +#ifdef BFD64 + if (elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64) + r_symndx = ELF64_R_SYM (rel->r_info); + else +#endif + r_symndx = ELF32_R_SYM (rel->r_info); + if (r_symndx >= cookie->locsymcount + || ELF_ST_BIND (cookie->locsyms[r_symndx].st_info) != STB_LOCAL) + { + struct elf_link_hash_entry *h; + + r_symndx -= cookie->extsymoff; + h = cookie->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; + + cie->personality.h = h; + per_binds_local = SYMBOL_REFERENCES_LOCAL (info, h); + } + else + { + Elf_Internal_Sym *sym; + asection *sym_sec; + + sym = &cookie->locsyms[r_symndx]; + sym_sec = bfd_section_from_elf_index (abfd, sym->st_shndx); + if (sym_sec == NULL) + return cie_inf; + + if (sym_sec->kept_section != NULL) + sym_sec = sym_sec->kept_section; + if (sym_sec->output_section == NULL) + return cie_inf; + + cie->local_personality = 1; + cie->personality.val = (sym->st_value + + sym_sec->output_offset + + sym_sec->output_section->vma); + per_binds_local = TRUE; + } + + if (per_binds_local + && info->shared + && (cie->per_encoding & 0x70) == DW_EH_PE_absptr + && (get_elf_backend_data (abfd) + ->elf_backend_can_make_relative_eh_frame (abfd, info, sec))) + { + cie_inf->u.cie.make_per_encoding_relative = 1; + cie_inf->u.cie.per_encoding_relative = 1; + } + } + + /* See if we can merge this CIE with an earlier one. */ + cie->output_sec = sec->output_section; + cie_compute_hash (cie); + if (hdr_info->cies == NULL) + { + hdr_info->cies = htab_try_create (1, cie_hash, cie_eq, free); + if (hdr_info->cies == NULL) + return cie_inf; + } + loc = htab_find_slot_with_hash (hdr_info->cies, cie, cie->hash, INSERT); + if (loc == NULL) + return cie_inf; + + new_cie = (struct cie *) *loc; + if (new_cie == NULL) + { + /* Keep CIE_INF and record it in the hash table. */ + new_cie = (struct cie *) malloc (sizeof (struct cie)); + if (new_cie == NULL) + return cie_inf; + + memcpy (new_cie, cie, sizeof (struct cie)); + *loc = new_cie; + } + else + { + /* Merge CIE_INF with NEW_CIE->CIE_INF. */ + cie_inf->removed = 1; + cie_inf->u.cie.merged = 1; + cie_inf->u.cie.u.merged_with = new_cie->cie_inf; + if (cie_inf->u.cie.make_lsda_relative) + new_cie->cie_inf->u.cie.make_lsda_relative = 1; + } + return new_cie->cie_inf; +} + +/* 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; + struct eh_frame_sec_info *sec_info; + struct eh_frame_hdr_info *hdr_info; + unsigned int ptr_size, offset; + + if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME) + return FALSE; + + sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; + if (sec_info == NULL) + return FALSE; + + ptr_size = (get_elf_backend_data (sec->owner) + ->elf_backend_eh_frame_address_size (sec->owner, sec)); + + hdr_info = &elf_hash_table (info)->eh_info; + for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) + if (ent->size == 4) + /* There should only be one zero terminator, on the last input + file supplying .eh_frame (crtend.o). Remove any others. */ + ent->removed = sec->map_head.s != NULL; + else if (!ent->cie) + { + bfd_boolean keep; + if ((sec->flags & SEC_LINKER_CREATED) != 0 && cookie->rels == NULL) + { + unsigned int width + = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); + bfd_vma value + = read_value (abfd, sec->contents + ent->offset + 8 + width, + width, get_DW_EH_PE_signed (ent->fde_encoding)); + keep = value != 0; + } + else + { + cookie->rel = cookie->rels + ent->reloc_index; + /* FIXME: octets_per_byte. */ + BFD_ASSERT (cookie->rel < cookie->relend + && cookie->rel->r_offset == ent->offset + 8); + keep = !(*reloc_symbol_deleted_p) (ent->offset + 8, cookie); + } + if (keep) + { + if (info->shared + && (((ent->fde_encoding & 0x70) == DW_EH_PE_absptr + && ent->make_relative == 0) + || (ent->fde_encoding & 0x70) == 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++; + ent->u.fde.cie_inf = find_merged_cie (abfd, info, sec, hdr_info, + cookie, ent->u.fde.cie_inf); + } + } + + if (sec_info->cies) + { + free (sec_info->cies); + sec_info->cies = NULL; + } + + 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); + } + + sec->rawsize = sec->size; + sec->size = offset; + return offset != sec->rawsize; +} + +/* This function is called for .eh_frame_hdr section after + _bfd_elf_discard_section_eh_frame has been called on all .eh_frame + input sections. It finalizes the size of .eh_frame_hdr section. */ + +bfd_boolean +_bfd_elf_discard_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) +{ + struct elf_link_hash_table *htab; + struct eh_frame_hdr_info *hdr_info; + asection *sec; + + 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; + + sec->size = EH_FRAME_HDR_SIZE; + if (hdr_info->table) + sec->size += 4 + hdr_info->fde_count * 8; + + elf_eh_frame_hdr (abfd) = sec; + return TRUE; +} + +/* Return true if there is at least one non-empty .eh_frame section in + input files. Can only be called after ld has mapped input to + output sections, and before sections are stripped. */ +bfd_boolean +_bfd_elf_eh_frame_present (struct bfd_link_info *info) +{ + asection *eh = bfd_get_section_by_name (info->output_bfd, ".eh_frame"); + + if (eh == NULL) + return FALSE; + + /* Count only sections which have at least a single CIE or FDE. + There cannot be any CIE or FDE <= 8 bytes. */ + for (eh = eh->map_head.s; eh != NULL; eh = eh->map_head.s) + if (eh->size > 8) + return TRUE; + + return FALSE; +} + +/* This function is called from size_dynamic_sections. + It needs to decide whether .eh_frame_hdr should be output or not, + because when the dynamic symbol table has been sized it is too late + to strip sections. */ + +bfd_boolean +_bfd_elf_maybe_strip_eh_frame_hdr (struct bfd_link_info *info) +{ + struct elf_link_hash_table *htab; + struct eh_frame_hdr_info *hdr_info; + + htab = elf_hash_table (info); + hdr_info = &htab->eh_info; + if (hdr_info->hdr_sec == NULL) + return TRUE; + + if (bfd_is_abs_section (hdr_info->hdr_sec->output_section) + || !info->eh_frame_hdr + || !_bfd_elf_eh_frame_present (info)) + { + hdr_info->hdr_sec->flags |= SEC_EXCLUDE; + hdr_info->hdr_sec = NULL; + return TRUE; + } + + hdr_info->table = TRUE; + return TRUE; +} + +/* Adjust an address in the .eh_frame section. Given OFFSET within + SEC, this returns the new offset in the adjusted .eh_frame section, + or -1 if the address refers to a CIE/FDE which has been removed + or to offset with dynamic relocation which is no longer needed. */ + +bfd_vma +_bfd_elf_eh_frame_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, + struct bfd_link_info *info ATTRIBUTE_UNUSED, + asection *sec, + bfd_vma offset) +{ + struct eh_frame_sec_info *sec_info; + unsigned int lo, hi, mid; + + if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME) + return offset; + sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; + + if (offset >= sec->rawsize) + return offset - sec->rawsize + sec->size; + + lo = 0; + hi = sec_info->count; + mid = 0; + while (lo < hi) + { + mid = (lo + hi) / 2; + if (offset < sec_info->entry[mid].offset) + hi = mid; + else if (offset + >= sec_info->entry[mid].offset + sec_info->entry[mid].size) + lo = mid + 1; + else + break; + } + + BFD_ASSERT (lo < hi); + + /* FDE or CIE was removed. */ + if (sec_info->entry[mid].removed) + return (bfd_vma) -1; + + /* If converting personality pointers to DW_EH_PE_pcrel, there will be + no need for run-time relocation against the personality field. */ + if (sec_info->entry[mid].cie + && sec_info->entry[mid].u.cie.make_per_encoding_relative + && offset == (sec_info->entry[mid].offset + 8 + + sec_info->entry[mid].u.cie.personality_offset)) + return (bfd_vma) -2; + + /* If converting to DW_EH_PE_pcrel, there will be no need for run-time + relocation against FDE's initial_location field. */ + if (!sec_info->entry[mid].cie + && sec_info->entry[mid].make_relative + && offset == sec_info->entry[mid].offset + 8) + return (bfd_vma) -2; + + /* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need + for run-time relocation against LSDA field. */ + if (!sec_info->entry[mid].cie + && sec_info->entry[mid].u.fde.cie_inf->u.cie.make_lsda_relative + && offset == (sec_info->entry[mid].offset + 8 + + sec_info->entry[mid].lsda_offset)) + return (bfd_vma) -2; + + /* If converting to DW_EH_PE_pcrel, there will be no need for run-time + relocation against DW_CFA_set_loc's arguments. */ + if (sec_info->entry[mid].set_loc + && sec_info->entry[mid].make_relative + && (offset >= sec_info->entry[mid].offset + 8 + + sec_info->entry[mid].set_loc[1])) + { + unsigned int cnt; + + for (cnt = 1; cnt <= sec_info->entry[mid].set_loc[0]; cnt++) + if (offset == sec_info->entry[mid].offset + 8 + + sec_info->entry[mid].set_loc[cnt]) + return (bfd_vma) -2; + } + + /* Any new augmentation bytes go before the first relocation. */ + return (offset + sec_info->entry[mid].new_offset + - sec_info->entry[mid].offset + + extra_augmentation_string_bytes (sec_info->entry + mid) + + extra_augmentation_data_bytes (sec_info->entry + mid)); +} + +/* Write out .eh_frame section. This is called with the relocated + contents. */ + +bfd_boolean +_bfd_elf_write_section_eh_frame (bfd *abfd, + struct bfd_link_info *info, + asection *sec, + bfd_byte *contents) +{ + struct eh_frame_sec_info *sec_info; + struct elf_link_hash_table *htab; + struct eh_frame_hdr_info *hdr_info; + unsigned int ptr_size; + struct eh_cie_fde *ent; + + if (sec->sec_info_type != SEC_INFO_TYPE_EH_FRAME) + /* FIXME: octets_per_byte. */ + return bfd_set_section_contents (abfd, sec->output_section, contents, + sec->output_offset, sec->size); + + ptr_size = (get_elf_backend_data (abfd) + ->elf_backend_eh_frame_address_size (abfd, sec)); + BFD_ASSERT (ptr_size != 0); + + sec_info = (struct eh_frame_sec_info *) elf_section_data (sec)->sec_info; + htab = elf_hash_table (info); + hdr_info = &htab->eh_info; + + if (hdr_info->table && hdr_info->array == NULL) + hdr_info->array = (struct eh_frame_array_ent *) + bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array)); + if (hdr_info->array == NULL) + hdr_info = NULL; + + /* The new offsets can be bigger or smaller than the original offsets. + We therefore need to make two passes over the section: one backward + pass to move entries up and one forward pass to move entries down. + The two passes won't interfere with each other because entries are + not reordered */ + for (ent = sec_info->entry + sec_info->count; ent-- != sec_info->entry;) + if (!ent->removed && ent->new_offset > ent->offset) + memmove (contents + ent->new_offset, contents + ent->offset, ent->size); + + for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) + if (!ent->removed && ent->new_offset < ent->offset) + memmove (contents + ent->new_offset, contents + ent->offset, ent->size); + + for (ent = sec_info->entry; ent < sec_info->entry + sec_info->count; ++ent) + { + unsigned char *buf, *end; + unsigned int new_size; + + if (ent->removed) + continue; + + if (ent->size == 4) + { + /* Any terminating FDE must be at the end of the section. */ + BFD_ASSERT (ent == sec_info->entry + sec_info->count - 1); + continue; + } + + buf = contents + ent->new_offset; + end = buf + ent->size; + new_size = size_of_output_cie_fde (ent, ptr_size); + + /* Update the size. It may be shrinked. */ + bfd_put_32 (abfd, new_size - 4, buf); + + /* Filling the extra bytes with DW_CFA_nops. */ + if (new_size != ent->size) + memset (end, 0, new_size - ent->size); + + if (ent->cie) + { + /* CIE */ + if (ent->make_relative + || ent->u.cie.make_lsda_relative + || ent->u.cie.per_encoding_relative) + { + char *aug; + unsigned int action, extra_string, extra_data; + unsigned int per_width, per_encoding; + + /* Need to find 'R' or 'L' augmentation's argument and modify + DW_EH_PE_* value. */ + action = ((ent->make_relative ? 1 : 0) + | (ent->u.cie.make_lsda_relative ? 2 : 0) + | (ent->u.cie.per_encoding_relative ? 4 : 0)); + extra_string = extra_augmentation_string_bytes (ent); + extra_data = extra_augmentation_data_bytes (ent); + + /* Skip length, id and version. */ + buf += 9; + aug = (char *) buf; + buf += strlen (aug) + 1; + skip_leb128 (&buf, end); + skip_leb128 (&buf, end); + skip_leb128 (&buf, end); + if (*aug == 'z') + { + /* The uleb128 will always be a single byte for the kind + of augmentation strings that we're prepared to handle. */ + *buf++ += extra_data; + aug++; + } + + /* Make room for the new augmentation string and data bytes. */ + memmove (buf + extra_string + extra_data, buf, end - buf); + memmove (aug + extra_string, aug, buf - (bfd_byte *) aug); + buf += extra_string; + end += extra_string + extra_data; + + if (ent->add_augmentation_size) + { + *aug++ = 'z'; + *buf++ = extra_data - 1; + } + if (ent->u.cie.add_fde_encoding) + { + BFD_ASSERT (action & 1); + *aug++ = 'R'; + *buf++ = make_pc_relative (DW_EH_PE_absptr, ptr_size); + action &= ~1; + } + + while (action) + switch (*aug++) + { + case 'L': + if (action & 2) + { + BFD_ASSERT (*buf == ent->lsda_encoding); + *buf = make_pc_relative (*buf, ptr_size); + action &= ~2; + } + buf++; + break; + case 'P': + if (ent->u.cie.make_per_encoding_relative) + *buf = make_pc_relative (*buf, ptr_size); + per_encoding = *buf++; + per_width = get_DW_EH_PE_width (per_encoding, ptr_size); + BFD_ASSERT (per_width != 0); + BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel) + == ent->u.cie.per_encoding_relative); + if ((per_encoding & 0x70) == DW_EH_PE_aligned) + buf = (contents + + ((buf - contents + per_width - 1) + & ~((bfd_size_type) per_width - 1))); + if (action & 4) + { + bfd_vma val; + + val = read_value (abfd, buf, per_width, + get_DW_EH_PE_signed (per_encoding)); + if (ent->u.cie.make_per_encoding_relative) + val -= (sec->output_section->vma + + sec->output_offset + + (buf - contents)); + else + { + val += (bfd_vma) ent->offset - ent->new_offset; + val -= extra_string + extra_data; + } + write_value (abfd, buf, val, per_width); + action &= ~4; + } + buf += per_width; + break; + case 'R': + if (action & 1) + { + BFD_ASSERT (*buf == ent->fde_encoding); + *buf = make_pc_relative (*buf, ptr_size); + action &= ~1; + } + buf++; + break; + case 'S': + break; + default: + BFD_FAIL (); + } + } + } + else + { + /* FDE */ + bfd_vma value, address; + unsigned int width; + bfd_byte *start; + struct eh_cie_fde *cie; + + /* Skip length. */ + cie = ent->u.fde.cie_inf; + buf += 4; + value = ((ent->new_offset + sec->output_offset + 4) + - (cie->new_offset + cie->u.cie.u.sec->output_offset)); + bfd_put_32 (abfd, value, buf); + buf += 4; + width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); + value = read_value (abfd, buf, width, + get_DW_EH_PE_signed (ent->fde_encoding)); + address = value; + if (value) + { + switch (ent->fde_encoding & 0x70) + { + case DW_EH_PE_textrel: + BFD_ASSERT (hdr_info == NULL); + break; + case DW_EH_PE_datarel: + { + switch (abfd->arch_info->arch) + { + case bfd_arch_ia64: + BFD_ASSERT (elf_gp (abfd) != 0); + address += elf_gp (abfd); + break; + default: + (*info->callbacks->einfo) + (_("%P: DW_EH_PE_datarel unspecified" + " for this architecture.\n")); + /* Fall thru */ + case bfd_arch_frv: + case bfd_arch_i386: + BFD_ASSERT (htab->hgot != NULL + && ((htab->hgot->root.type + == bfd_link_hash_defined) + || (htab->hgot->root.type + == bfd_link_hash_defweak))); + address + += (htab->hgot->root.u.def.value + + htab->hgot->root.u.def.section->output_offset + + (htab->hgot->root.u.def.section->output_section + ->vma)); + break; + } + } + break; + case DW_EH_PE_pcrel: + value += (bfd_vma) ent->offset - ent->new_offset; + address += (sec->output_section->vma + + sec->output_offset + + ent->offset + 8); + break; + } + if (ent->make_relative) + value -= (sec->output_section->vma + + sec->output_offset + + ent->new_offset + 8); + write_value (abfd, buf, value, width); + } + + start = buf; + + if (hdr_info) + { + /* The address calculation may overflow, giving us a + value greater than 4G on a 32-bit target when + dwarf_vma is 64-bit. */ + if (sizeof (address) > 4 && ptr_size == 4) + address &= 0xffffffff; + hdr_info->array[hdr_info->array_count].initial_loc = address; + hdr_info->array[hdr_info->array_count++].fde + = (sec->output_section->vma + + sec->output_offset + + ent->new_offset); + } + + if ((ent->lsda_encoding & 0x70) == DW_EH_PE_pcrel + || cie->u.cie.make_lsda_relative) + { + buf += ent->lsda_offset; + width = get_DW_EH_PE_width (ent->lsda_encoding, ptr_size); + value = read_value (abfd, buf, width, + get_DW_EH_PE_signed (ent->lsda_encoding)); + if (value) + { + if ((ent->lsda_encoding & 0x70) == DW_EH_PE_pcrel) + value += (bfd_vma) ent->offset - ent->new_offset; + else if (cie->u.cie.make_lsda_relative) + value -= (sec->output_section->vma + + sec->output_offset + + ent->new_offset + 8 + ent->lsda_offset); + write_value (abfd, buf, value, width); + } + } + else if (ent->add_augmentation_size) + { + /* Skip the PC and length and insert a zero byte for the + augmentation size. */ + buf += width * 2; + memmove (buf + 1, buf, end - buf); + *buf = 0; + } + + if (ent->set_loc) + { + /* Adjust DW_CFA_set_loc. */ + unsigned int cnt; + bfd_vma new_offset; + + width = get_DW_EH_PE_width (ent->fde_encoding, ptr_size); + new_offset = ent->new_offset + 8 + + extra_augmentation_string_bytes (ent) + + extra_augmentation_data_bytes (ent); + + for (cnt = 1; cnt <= ent->set_loc[0]; cnt++) + { + buf = start + ent->set_loc[cnt]; + + value = read_value (abfd, buf, width, + get_DW_EH_PE_signed (ent->fde_encoding)); + if (!value) + continue; + + if ((ent->fde_encoding & 0x70) == DW_EH_PE_pcrel) + value += (bfd_vma) ent->offset + 8 - new_offset; + if (ent->make_relative) + value -= (sec->output_section->vma + + sec->output_offset + + new_offset + ent->set_loc[cnt]); + write_value (abfd, buf, value, width); + } + } + } + } + + /* We don't align the section to its section alignment since the + runtime library only expects all CIE/FDE records aligned at + the pointer size. _bfd_elf_discard_section_eh_frame should + have padded CIE/FDE records to multiple of pointer size with + size_of_output_cie_fde. */ + if ((sec->size % ptr_size) != 0) + abort (); + + /* FIXME: octets_per_byte. */ + return bfd_set_section_contents (abfd, sec->output_section, + contents, (file_ptr) sec->output_offset, + sec->size); +} + +/* Helper function used to sort .eh_frame_hdr search table by increasing + VMA of FDE initial location. */ + +static int +vma_compare (const void *a, const void *b) +{ + const struct eh_frame_array_ent *p = (const struct eh_frame_array_ent *) a; + const struct eh_frame_array_ent *q = (const struct eh_frame_array_ent *) b; + if (p->initial_loc > q->initial_loc) + return 1; + if (p->initial_loc < q->initial_loc) + return -1; + return 0; +} + +/* Write out .eh_frame_hdr section. This must be called after + _bfd_elf_write_section_eh_frame has been called on all input + .eh_frame sections. + .eh_frame_hdr format: + ubyte version (currently 1) + ubyte eh_frame_ptr_enc (DW_EH_PE_* encoding of pointer to start of + .eh_frame section) + ubyte fde_count_enc (DW_EH_PE_* encoding of total FDE count + number (or DW_EH_PE_omit if there is no + binary search table computed)) + ubyte table_enc (DW_EH_PE_* encoding of binary search table, + or DW_EH_PE_omit if not present. + DW_EH_PE_datarel is using address of + .eh_frame_hdr section start as base) + [encoded] eh_frame_ptr (pointer to start of .eh_frame section) + optionally followed by: + [encoded] fde_count (total number of FDEs in .eh_frame section) + fde_count x [encoded] initial_loc, fde + (array of encoded pairs containing + FDE initial_location field and FDE address, + sorted by increasing initial_loc). */ + +bfd_boolean +_bfd_elf_write_section_eh_frame_hdr (bfd *abfd, struct bfd_link_info *info) +{ + struct elf_link_hash_table *htab; + struct eh_frame_hdr_info *hdr_info; + asection *sec; + bfd_boolean retval = TRUE; + + htab = elf_hash_table (info); + hdr_info = &htab->eh_info; + sec = hdr_info->hdr_sec; + + if (info->eh_frame_hdr && sec != NULL) + { + bfd_byte *contents; + asection *eh_frame_sec; + bfd_size_type size; + bfd_vma encoded_eh_frame; + + size = EH_FRAME_HDR_SIZE; + if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) + size += 4 + hdr_info->fde_count * 8; + contents = (bfd_byte *) bfd_malloc (size); + if (contents == NULL) + return FALSE; + + eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame"); + if (eh_frame_sec == NULL) + { + free (contents); + return FALSE; + } + + memset (contents, 0, EH_FRAME_HDR_SIZE); + /* Version. */ + contents[0] = 1; + /* .eh_frame offset. */ + contents[1] = get_elf_backend_data (abfd)->elf_backend_encode_eh_address + (abfd, info, eh_frame_sec, 0, sec, 4, &encoded_eh_frame); + + if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count) + { + /* FDE count encoding. */ + contents[2] = DW_EH_PE_udata4; + /* Search table encoding. */ + contents[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; + } + else + { + contents[2] = DW_EH_PE_omit; + contents[3] = DW_EH_PE_omit; + } + bfd_put_32 (abfd, encoded_eh_frame, contents + 4); + + if (contents[2] != DW_EH_PE_omit) + { + unsigned int i; + + bfd_put_32 (abfd, hdr_info->fde_count, contents + EH_FRAME_HDR_SIZE); + qsort (hdr_info->array, hdr_info->fde_count, + sizeof (*hdr_info->array), vma_compare); + for (i = 0; i < hdr_info->fde_count; i++) + { + bfd_put_32 (abfd, + hdr_info->array[i].initial_loc + - sec->output_section->vma, + contents + EH_FRAME_HDR_SIZE + i * 8 + 4); + bfd_put_32 (abfd, + hdr_info->array[i].fde - sec->output_section->vma, + contents + EH_FRAME_HDR_SIZE + i * 8 + 8); + } + } + + /* FIXME: octets_per_byte. */ + retval = bfd_set_section_contents (abfd, sec->output_section, contents, + (file_ptr) sec->output_offset, + sec->size); + free (contents); + } + if (hdr_info->array != NULL) + free (hdr_info->array); + return retval; +} + +/* Return the width of FDE addresses. This is the default implementation. */ + +unsigned int +_bfd_elf_eh_frame_address_size (bfd *abfd, asection *sec ATTRIBUTE_UNUSED) +{ + return elf_elfheader (abfd)->e_ident[EI_CLASS] == ELFCLASS64 ? 8 : 4; +} + +/* Decide whether we can use a PC-relative encoding within the given + EH frame section. This is the default implementation. */ + +bfd_boolean +_bfd_elf_can_make_relative (bfd *input_bfd ATTRIBUTE_UNUSED, + struct bfd_link_info *info ATTRIBUTE_UNUSED, + asection *eh_frame_section ATTRIBUTE_UNUSED) +{ + return TRUE; +} + +/* Select an encoding for the given address. Preference is given to + PC-relative addressing modes. */ + +bfd_byte +_bfd_elf_encode_eh_address (bfd *abfd ATTRIBUTE_UNUSED, + struct bfd_link_info *info ATTRIBUTE_UNUSED, + asection *osec, bfd_vma offset, + asection *loc_sec, bfd_vma loc_offset, + bfd_vma *encoded) +{ + *encoded = osec->vma + offset - + (loc_sec->output_section->vma + loc_sec->output_offset + loc_offset); + return DW_EH_PE_pcrel | DW_EH_PE_sdata4; +} |