From 9b9b572f7d45495fb7988f86df24ee8fa074b01f Mon Sep 17 00:00:00 2001 From: Paul Brook Date: Mon, 9 May 2011 13:23:24 +0000 Subject: 2011-05-09 Paul Brook bfd/ * bfd-in.h (elf32_tic6x_fix_exidx_coverage): Add prototype. * bfd-in2.h: Regenerate. * elf32-tic6x.c: Include limits.h. (tic6x_unwind_edit_type, tic6x_unwind_table_edit, _tic6x_elf_section_data): New. (elf32_tic6x_section_data): Define. (elf32_tic6x_new_section_hook): Allocate target specific data. (elf32_tic6x_add_unwind_table_edit): New function. (get_tic6x_elf_section_data, elf32_tic6x_adjust_exidx_size, elf32_tic6x_insert_cantunwind_after, elf32_tic6x_add_low31, elf32_tic6x_copy_exidx_entry): New functions. (elf_backend_write_section): Define. ld/ * emultempl/tic6xdsbt.em (merge_exidx_entries): New. (compare_output_sec_vma): New function. (gld${EMULATION_NAME}_after_allocation): New function. (OPTION_NO_MERGE_EXIDX_ENTRIES): Define. (PARSE_AND_LIST_OPTIONS): Add --no-merge-exidx-entries. (PARSE_AND_LIST_ARGS_CASES): Add OPTION_NO_MERGE_EXIDX_ENTRIES. (LDEMUL_AFTER_ALLOCATION): Set. * ld.texinfo: Document c6x --no-merge-exidx-entries. ld/testsuite/ * ld-tic6x/discard-unwind.ld: New. * ld-tic6x/unwind.ld: New. * ld-tic6x/unwind-1.d: New test. * ld-tic6x/unwind-1.s: New test. * ld-tic6x/unwind-2.d: New test. * ld-tic6x/unwind-2.s: New test. * ld-tic6x/unwind-3.d: New test. * ld-tic6x/unwind-3.s: New test. * ld-tic6x/unwind-4.d: New test. * ld-tic6x/unwind-4.s: New test. * ld-tic6x/unwind-5.d: New test. * ld-tic6x/unwind-5.s: New test. * ld-tic6x/unwind-6.d: New test. --- bfd/elf32-tic6x.c | 463 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 463 insertions(+) (limited to 'bfd/elf32-tic6x.c') diff --git a/bfd/elf32-tic6x.c b/bfd/elf32-tic6x.c index a70ef01c05..fb710dc1d9 100644 --- a/bfd/elf32-tic6x.c +++ b/bfd/elf32-tic6x.c @@ -22,6 +22,7 @@ MA 02110-1301, USA. */ #include "sysdep.h" +#include #include "bfd.h" #include "libbfd.h" #include "libiberty.h" @@ -75,6 +76,52 @@ struct elf32_tic6x_link_hash_entry struct elf_dyn_relocs *dyn_relocs; }; +typedef enum +{ + DELETE_EXIDX_ENTRY, + INSERT_EXIDX_CANTUNWIND_AT_END +} +tic6x_unwind_edit_type; + +/* A (sorted) list of edits to apply to an unwind table. */ +typedef struct tic6x_unwind_table_edit +{ + tic6x_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 tic6x_unwind_table_edit *next; +} +tic6x_unwind_table_edit; + +typedef struct _tic6x_elf_section_data +{ + /* Information about mapping symbols. */ + struct bfd_elf_section_data elf; + /* Information about unwind tables. */ + union + { + /* Unwind info attached to a text section. */ + struct + { + asection *tic6x_exidx_sec; + } text; + + /* Unwind info attached to an .c6xabi.exidx section. */ + struct + { + tic6x_unwind_table_edit *unwind_edit_list; + tic6x_unwind_table_edit *unwind_edit_tail; + } exidx; + } u; +} +_tic6x_elf_section_data; + +#define elf32_tic6x_section_data(sec) \ + ((_tic6x_elf_section_data *) elf_section_data (sec)) + struct elf32_tic6x_obj_tdata { struct elf_obj_tdata root; @@ -2120,6 +2167,18 @@ elf32_tic6x_new_section_hook (bfd *abfd, asection *sec) { bfd_boolean ret; + /* Allocate target specific section data. */ + if (!sec->used_by_bfd) + { + _tic6x_elf_section_data *sdata; + bfd_size_type amt = sizeof (*sdata); + + sdata = (_tic6x_elf_section_data *) bfd_zalloc (abfd, amt); + if (sdata == NULL) + return FALSE; + sec->used_by_bfd = sdata; + } + ret = _bfd_elf_new_section_hook (abfd, sec); sec->use_rela_p = elf32_tic6x_tdata (abfd)->use_rela_p; @@ -3977,6 +4036,409 @@ elf32_tic6x_copy_private_data (bfd * ibfd, bfd * obfd) return TRUE; } +/* Add a new unwind edit to the list described by HEAD, TAIL. If TINDEX is zero, + adds the edit to the start of the list. (The list must be built in order of + ascending TINDEX: the function's callers are primarily responsible for + maintaining that condition). */ + +static void +elf32_tic6x_add_unwind_table_edit (tic6x_unwind_table_edit **head, + tic6x_unwind_table_edit **tail, + tic6x_unwind_edit_type type, + asection *linked_section, + unsigned int tindex) +{ + tic6x_unwind_table_edit *new_edit = (tic6x_unwind_table_edit *) + xmalloc (sizeof (tic6x_unwind_table_edit)); + + new_edit->type = type; + new_edit->linked_section = linked_section; + new_edit->index = tindex; + + if (tindex > 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 _tic6x_elf_section_data * +get_tic6x_elf_section_data (asection * sec) +{ + if (sec && sec->owner && is_tic6x_elf (sec->owner)) + return elf32_tic6x_section_data (sec); + else + return NULL; +} + + +/* Increase the size of EXIDX_SEC by ADJUST bytes. ADJUST must be negative. */ +static void +elf32_tic6x_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 +elf32_tic6x_insert_cantunwind_after (asection *text_sec, asection *exidx_sec) +{ + struct _tic6x_elf_section_data *exidx_data; + + exidx_data = get_tic6x_elf_section_data (exidx_sec); + elf32_tic6x_add_unwind_table_edit ( + &exidx_data->u.exidx.unwind_edit_list, + &exidx_data->u.exidx.unwind_edit_tail, + INSERT_EXIDX_CANTUNWIND_AT_END, text_sec, UINT_MAX); + + elf32_tic6x_adjust_exidx_size (exidx_sec, 8); +} + +/* Scan .cx6abi.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). + + If MERGE_EXIDX_ENTRIES is false, duplicate entries are not merged. + + The edits are applied when the tables are written + (in elf32_tic6x_write_section). +*/ + +bfd_boolean +elf32_tic6x_fix_exidx_coverage (asection **text_section_order, + unsigned int num_text_sections, + struct bfd_link_info *info, + bfd_boolean merge_exidx_entries) +{ + 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 || hdr->sh_type != SHT_C6000_UNWIND) + continue; + + if (elf_sec->linked_to) + { + Elf_Internal_Shdr *linked_hdr + = &elf_section_data (elf_sec->linked_to)->this_hdr; + struct _tic6x_elf_section_data *linked_sec_tic6x_data + = get_tic6x_elf_section_data (linked_hdr->bfd_section); + + if (linked_sec_tic6x_data == NULL) + continue; + + /* Link this .c6xabi.exidx section back from the + text section it describes. */ + linked_sec_tic6x_data->u.text.tic6x_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 _tic6x_elf_section_data *tic6x_data + = get_tic6x_elf_section_data (sec); + struct _tic6x_elf_section_data *exidx_data; + bfd_byte *contents = NULL; + int deleted_exidx_bytes = 0; + bfd_vma j; + tic6x_unwind_table_edit *unwind_edit_head = NULL; + tic6x_unwind_table_edit *unwind_edit_tail = NULL; + Elf_Internal_Shdr *hdr; + bfd *ibfd; + + if (tic6x_data == NULL) + continue; + + exidx_sec = tic6x_data->u.text.tic6x_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; + + elf32_tic6x_insert_cantunwind_after (last_text_sec, last_exidx_sec); + last_unwind_type = 0; + continue; + } + + /* Skip /DISCARD/ sections. */ + if (bfd_is_abs_section (exidx_sec->output_section)) + continue; + + hdr = &elf_section_data (exidx_sec)->this_hdr; + if (hdr->sh_type != SHT_C6000_UNWIND) + continue; + + exidx_data = get_tic6x_elf_section_data (exidx_sec); + if (exidx_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 (merge_exidx_entries + && 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) + { + elf32_tic6x_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_tic6x_write_section). */ + exidx_data->u.exidx.unwind_edit_list = unwind_edit_head; + exidx_data->u.exidx.unwind_edit_tail = unwind_edit_tail; + + if (deleted_exidx_bytes > 0) + elf32_tic6x_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) + elf32_tic6x_insert_cantunwind_after (last_text_sec, last_exidx_sec); + + return TRUE; +} + +/* Add ADDEND to lower 31 bits of VAL, leaving other bits unmodified. */ + +static unsigned long +elf32_tic6x_add_low31 (unsigned long val, bfd_vma addend) +{ + return (val & ~0x7ffffffful) | ((val + addend) & 0x7ffffffful); +} + +/* Copy an .c6xabi.exidx table entry, adding OFFSET to (applied) PREL31 + relocations. OFFSET is in bytes, and will be scaled before encoding. */ + + +static void +elf32_tic6x_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); + + offset >>= 1; + /* High bit of first word is supposed to be zero. */ + if ((first_word & 0x80000000ul) == 0) + first_word = elf32_tic6x_add_low31 (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 .c6xabi.extab entry. */ + if ((second_word != 0x1) && ((second_word & 0x80000000ul) == 0)) + second_word = elf32_tic6x_add_low31 (second_word, offset); + + bfd_put_32 (output_bfd, first_word, to); + bfd_put_32 (output_bfd, second_word, to + 4); +} + +/* Do the actual mangling of exception index tables. */ + +static bfd_boolean +elf32_tic6x_write_section (bfd *output_bfd, + struct bfd_link_info *link_info, + asection *sec, + bfd_byte *contents) +{ + _tic6x_elf_section_data *tic6x_data; + struct elf32_tic6x_link_hash_table *globals + = elf32_tic6x_hash_table (link_info); + bfd_vma offset = sec->output_section->vma + sec->output_offset; + + if (globals == NULL) + return FALSE; + + /* If this section has not been allocated an _tic6x_elf_section_data + structure then we cannot record anything. */ + tic6x_data = get_tic6x_elf_section_data (sec); + if (tic6x_data == NULL) + return FALSE; + + if (tic6x_data->elf.this_hdr.sh_type != SHT_C6000_UNWIND) + return FALSE; + + tic6x_unwind_table_edit *edit_node + = tic6x_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_byte *) 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) + { + elf32_tic6x_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_C6000_PREL31 relocation. These synthetic + EXIDX_CANTUNWIND markers are not relocated by the + usual BFD method. */ + prel31_offset = ((text_offset - exidx_offset) >> 1) + & 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. */ + elf32_tic6x_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; +} + #define TARGET_LITTLE_SYM bfd_elf32_tic6x_le_vec #define TARGET_LITTLE_NAME "elf32-tic6x-le" #define TARGET_BIG_SYM bfd_elf32_tic6x_be_vec @@ -4036,6 +4498,7 @@ elf32_tic6x_copy_private_data (bfd * ibfd, bfd * obfd) elf32_tic6x_finish_dynamic_sections #define bfd_elf32_bfd_final_link \ elf32_tic6x_final_link +#define elf_backend_write_section elf32_tic6x_write_section #define elf_info_to_howto elf32_tic6x_info_to_howto #define elf_info_to_howto_rel elf32_tic6x_info_to_howto_rel -- cgit v1.2.1