Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
+#include <limits.h>
+
#include "sysdep.h"
#include "bfd.h"
#include "libiberty.h"
}
elf32_vfp11_erratum_list;
+typedef enum
+{
+ DELETE_EXIDX_ENTRY,
+ INSERT_EXIDX_CANTUNWIND_AT_END
+}
+arm_unwind_edit_type;
+
+/* A (sorted) list of edits to apply to an unwind table. */
+typedef struct arm_unwind_table_edit
+{
+ arm_unwind_edit_type type;
+ /* Note: we sometimes want to insert an unwind entry corresponding to a
+ section different from the one we're currently writing out, so record the
+ (text) section this edit relates to here. */
+ asection *linked_section;
+ unsigned int index;
+ struct arm_unwind_table_edit *next;
+}
+arm_unwind_table_edit;
+
typedef struct _arm_elf_section_data
{
+ /* Information about mapping symbols. */
struct bfd_elf_section_data elf;
unsigned int mapcount;
unsigned int mapsize;
elf32_arm_section_map *map;
+ /* Information about CPU errata. */
unsigned int erratumcount;
elf32_vfp11_erratum_list *erratumlist;
+ /* Information about unwind tables. */
+ union
+ {
+ /* Unwind info attached to a text section. */
+ struct
+ {
+ asection *arm_exidx_sec;
+ } text;
+
+ /* Unwind info attached to an .ARM.exidx section. */
+ struct
+ {
+ arm_unwind_table_edit *unwind_edit_list;
+ arm_unwind_table_edit *unwind_edit_tail;
+ } exidx;
+ } u;
}
_arm_elf_section_data;
return TRUE;
}
+/* Add a new unwind edit to the list described by HEAD, TAIL. If INDEX is zero,
+ adds the edit to the start of the list. (The list must be built in order of
+ ascending INDEX: the function's callers are primarily responsible for
+ maintaining that condition). */
+
+static void
+add_unwind_table_edit (arm_unwind_table_edit **head,
+ arm_unwind_table_edit **tail,
+ arm_unwind_edit_type type,
+ asection *linked_section,
+ unsigned int index)
+{
+ arm_unwind_table_edit *new_edit = xmalloc (sizeof (arm_unwind_table_edit));
+
+ new_edit->type = type;
+ new_edit->linked_section = linked_section;
+ new_edit->index = index;
+
+ if (index > 0)
+ {
+ new_edit->next = NULL;
+
+ if (*tail)
+ (*tail)->next = new_edit;
+
+ (*tail) = new_edit;
+
+ if (!*head)
+ (*head) = new_edit;
+ }
+ else
+ {
+ new_edit->next = *head;
+
+ if (!*tail)
+ *tail = new_edit;
+
+ *head = new_edit;
+ }
+}
+
+static _arm_elf_section_data *get_arm_elf_section_data (asection *);
+
+/* Increase the size of EXIDX_SEC by ADJUST bytes. ADJUST mau be negative. */
+static void
+adjust_exidx_size(asection *exidx_sec, int adjust)
+{
+ asection *out_sec;
+
+ if (!exidx_sec->rawsize)
+ exidx_sec->rawsize = exidx_sec->size;
+
+ bfd_set_section_size (exidx_sec->owner, exidx_sec, exidx_sec->size + adjust);
+ out_sec = exidx_sec->output_section;
+ /* Adjust size of output section. */
+ bfd_set_section_size (out_sec->owner, out_sec, out_sec->size +adjust);
+}
+
+/* Insert an EXIDX_CANTUNWIND marker at the end of a section. */
+static void
+insert_cantunwind_after(asection *text_sec, asection *exidx_sec)
+{
+ struct _arm_elf_section_data *exidx_arm_data;
+
+ exidx_arm_data = get_arm_elf_section_data (exidx_sec);
+ add_unwind_table_edit (
+ &exidx_arm_data->u.exidx.unwind_edit_list,
+ &exidx_arm_data->u.exidx.unwind_edit_tail,
+ INSERT_EXIDX_CANTUNWIND_AT_END, text_sec, UINT_MAX);
+
+ adjust_exidx_size(exidx_sec, 8);
+}
+
+/* Scan .ARM.exidx tables, and create a list describing edits which should be
+ made to those tables, such that:
+
+ 1. Regions without unwind data are marked with EXIDX_CANTUNWIND entries.
+ 2. Duplicate entries are merged together (EXIDX_CANTUNWIND, or unwind
+ codes which have been inlined into the index).
+
+ The edits are applied when the tables are written
+ (in elf32_arm_write_section).
+*/
+
+bfd_boolean
+elf32_arm_fix_exidx_coverage (asection **text_section_order,
+ unsigned int num_text_sections,
+ struct bfd_link_info *info)
+{
+ bfd *inp;
+ unsigned int last_second_word = 0, i;
+ asection *last_exidx_sec = NULL;
+ asection *last_text_sec = NULL;
+ int last_unwind_type = -1;
+
+ /* Walk over all EXIDX sections, and create backlinks from the corrsponding
+ text sections. */
+ for (inp = info->input_bfds; inp != NULL; inp = inp->link_next)
+ {
+ asection *sec;
+
+ for (sec = inp->sections; sec != NULL; sec = sec->next)
+ {
+ struct bfd_elf_section_data *elf_sec = elf_section_data (sec);
+ Elf_Internal_Shdr *hdr = &elf_sec->this_hdr;
+
+ if (hdr->sh_type != SHT_ARM_EXIDX)
+ continue;
+
+ if (elf_sec->linked_to)
+ {
+ Elf_Internal_Shdr *linked_hdr
+ = &elf_section_data (elf_sec->linked_to)->this_hdr;
+ struct _arm_elf_section_data *linked_sec_arm_data
+ = get_arm_elf_section_data (linked_hdr->bfd_section);
+
+ if (linked_sec_arm_data == NULL)
+ continue;
+
+ /* Link this .ARM.exidx section back from the text section it
+ describes. */
+ linked_sec_arm_data->u.text.arm_exidx_sec = sec;
+ }
+ }
+ }
+
+ /* Walk all text sections in order of increasing VMA. Eilminate duplicate
+ index table entries (EXIDX_CANTUNWIND and inlined unwind opcodes),
+ and add EXIDX_CANTUNWIND entries for sections with no unwind table data.
+ */
+
+ for (i = 0; i < num_text_sections; i++)
+ {
+ asection *sec = text_section_order[i];
+ asection *exidx_sec;
+ struct _arm_elf_section_data *arm_data = get_arm_elf_section_data (sec);
+ struct _arm_elf_section_data *exidx_arm_data;
+ bfd_byte *contents = NULL;
+ int deleted_exidx_bytes = 0;
+ bfd_vma j;
+ arm_unwind_table_edit *unwind_edit_head = NULL;
+ arm_unwind_table_edit *unwind_edit_tail = NULL;
+ Elf_Internal_Shdr *hdr;
+ bfd *ibfd;
+
+ if (arm_data == NULL)
+ continue;
+
+ exidx_sec = arm_data->u.text.arm_exidx_sec;
+ if (exidx_sec == NULL)
+ {
+ /* Section has no unwind data. */
+ if (last_unwind_type == 0 || !last_exidx_sec)
+ continue;
+
+ /* Ignore zero sized sections. */
+ if (sec->size == 0)
+ continue;
+
+ insert_cantunwind_after(last_text_sec, last_exidx_sec);
+ last_unwind_type = 0;
+ continue;
+ }
+
+ hdr = &elf_section_data (exidx_sec)->this_hdr;
+ if (hdr->sh_type != SHT_ARM_EXIDX)
+ continue;
+
+ exidx_arm_data = get_arm_elf_section_data (exidx_sec);
+ if (exidx_arm_data == NULL)
+ continue;
+
+ ibfd = exidx_sec->owner;
+
+ if (hdr->contents != NULL)
+ contents = hdr->contents;
+ else if (! bfd_malloc_and_get_section (ibfd, exidx_sec, &contents))
+ /* An error? */
+ continue;
+
+ for (j = 0; j < hdr->sh_size; j += 8)
+ {
+ unsigned int second_word = bfd_get_32 (ibfd, contents + j + 4);
+ int unwind_type;
+ int elide = 0;
+
+ /* An EXIDX_CANTUNWIND entry. */
+ if (second_word == 1)
+ {
+ if (last_unwind_type == 0)
+ elide = 1;
+ unwind_type = 0;
+ }
+ /* Inlined unwinding data. Merge if equal to previous. */
+ else if ((second_word & 0x80000000) != 0)
+ {
+ if (last_second_word == second_word && last_unwind_type == 1)
+ elide = 1;
+ unwind_type = 1;
+ last_second_word = second_word;
+ }
+ /* Normal table entry. In theory we could merge these too,
+ but duplicate entries are likely to be much less common. */
+ else
+ unwind_type = 2;
+
+ if (elide)
+ {
+ add_unwind_table_edit (&unwind_edit_head, &unwind_edit_tail,
+ DELETE_EXIDX_ENTRY, NULL, j / 8);
+
+ deleted_exidx_bytes += 8;
+ }
+
+ last_unwind_type = unwind_type;
+ }
+
+ /* Free contents if we allocated it ourselves. */
+ if (contents != hdr->contents)
+ free (contents);
+
+ /* Record edits to be applied later (in elf32_arm_write_section). */
+ exidx_arm_data->u.exidx.unwind_edit_list = unwind_edit_head;
+ exidx_arm_data->u.exidx.unwind_edit_tail = unwind_edit_tail;
+
+ if (deleted_exidx_bytes > 0)
+ adjust_exidx_size(exidx_sec, -deleted_exidx_bytes);
+
+ last_exidx_sec = exidx_sec;
+ last_text_sec = sec;
+ }
+
+ /* Add terminating CANTUNWIND entry. */
+ if (last_exidx_sec && last_unwind_type != 0)
+ insert_cantunwind_after(last_text_sec, last_exidx_sec);
+
+ return TRUE;
+}
+
static bfd_boolean
elf32_arm_output_glue_section (struct bfd_link_info *info, bfd *obfd,
bfd *ibfd, const char *name)
return 0;
}
+/* Add OFFSET to lower 31 bits of ADDR, leaving other bits unmodified. */
+
+static unsigned long
+offset_prel31 (unsigned long addr, bfd_vma offset)
+{
+ return (addr & ~0x7ffffffful) | ((addr + offset) & 0x7ffffffful);
+}
+
+/* Copy an .ARM.exidx table entry, adding OFFSET to (applied) PREL31
+ relocations. */
+
+static void
+copy_exidx_entry (bfd *output_bfd, bfd_byte *to, bfd_byte *from, bfd_vma offset)
+{
+ unsigned long first_word = bfd_get_32 (output_bfd, from);
+ unsigned long second_word = bfd_get_32 (output_bfd, from + 4);
+
+ /* High bit of first word is supposed to be zero. */
+ if ((first_word & 0x80000000ul) == 0)
+ first_word = offset_prel31 (first_word, offset);
+
+ /* If the high bit of the first word is clear, and the bit pattern is not 0x1
+ (EXIDX_CANTUNWIND), this is an offset to an .ARM.extab entry. */
+ if ((second_word != 0x1) && ((second_word & 0x80000000ul) == 0))
+ second_word = offset_prel31 (second_word, offset);
+
+ bfd_put_32 (output_bfd, first_word, to);
+ bfd_put_32 (output_bfd, second_word, to + 4);
+}
/* Do code byteswapping. Return FALSE afterwards so that the section is
written out as normal. */
}
}
+ if (arm_data->elf.this_hdr.sh_type == SHT_ARM_EXIDX)
+ {
+ arm_unwind_table_edit *edit_node
+ = arm_data->u.exidx.unwind_edit_list;
+ /* Now, sec->size is the size of the section we will write. The original
+ size (before we merged duplicate entries and inserted EXIDX_CANTUNWIND
+ markers) was sec->rawsize. (This isn't the case if we perform no
+ edits, then rawsize will be zero and we should use size). */
+ bfd_byte *edited_contents = bfd_malloc (sec->size);
+ unsigned int input_size = sec->rawsize ? sec->rawsize : sec->size;
+ unsigned int in_index, out_index;
+ bfd_vma add_to_offsets = 0;
+
+ for (in_index = 0, out_index = 0; in_index * 8 < input_size || edit_node;)
+ {
+ if (edit_node)
+ {
+ unsigned int edit_index = edit_node->index;
+
+ if (in_index < edit_index && in_index * 8 < input_size)
+ {
+ copy_exidx_entry (output_bfd, edited_contents + out_index * 8,
+ contents + in_index * 8, add_to_offsets);
+ out_index++;
+ in_index++;
+ }
+ else if (in_index == edit_index
+ || (in_index * 8 >= input_size
+ && edit_index == UINT_MAX))
+ {
+ switch (edit_node->type)
+ {
+ case DELETE_EXIDX_ENTRY:
+ in_index++;
+ add_to_offsets += 8;
+ break;
+
+ case INSERT_EXIDX_CANTUNWIND_AT_END:
+ {
+ asection *text_sec = edit_node->linked_section;
+ bfd_vma text_offset = text_sec->output_section->vma
+ + text_sec->output_offset
+ + text_sec->size;
+ bfd_vma exidx_offset = offset + out_index * 8;
+ unsigned long prel31_offset;
+
+ /* Note: this is meant to be equivalent to an
+ R_ARM_PREL31 relocation. These synthetic
+ EXIDX_CANTUNWIND markers are not relocated by the
+ usual BFD method. */
+ prel31_offset = (text_offset - exidx_offset)
+ & 0x7ffffffful;
+
+ /* First address we can't unwind. */
+ bfd_put_32 (output_bfd, prel31_offset,
+ &edited_contents[out_index * 8]);
+
+ /* Code for EXIDX_CANTUNWIND. */
+ bfd_put_32 (output_bfd, 0x1,
+ &edited_contents[out_index * 8 + 4]);
+
+ out_index++;
+ add_to_offsets -= 8;
+ }
+ break;
+ }
+
+ edit_node = edit_node->next;
+ }
+ }
+ else
+ {
+ /* No more edits, copy remaining entries verbatim. */
+ copy_exidx_entry (output_bfd, edited_contents + out_index * 8,
+ contents + in_index * 8, add_to_offsets);
+ out_index++;
+ in_index++;
+ }
+ }
+
+ if (!(sec->flags & SEC_EXCLUDE) && !(sec->flags & SEC_NEVER_LOAD))
+ bfd_set_section_contents (output_bfd, sec->output_section,
+ edited_contents,
+ (file_ptr) sec->output_offset, sec->size);
+
+ return TRUE;
+ }
+
if (mapcount == 0)
return FALSE;
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