--- /dev/null
+From 20c79baf82273a0b368587f761f152c4d3a593a4 Mon Sep 17 00:00:00 2001
+From: Max Filippov <jcmvbkbc@gmail.com>
+Date: Fri, 27 Mar 2015 07:13:55 +0300
+Subject: [PATCH 1/4] xtensa: optimize check_section_ebb_pcrels_fit
+
+The original check_section_ebb_pcrels_fit algorithm checks that text
+actions proposed for current EBB are OK for every relocation in a
+section. There's no need to check every relocation, because text actions
+for EBB can only change size of that EBB, thus only affecting
+relocations that in any way cross that EBB. In addition EBBs are
+iterated in ascending order of their VMA, making it easier to track
+relevant relocations.
+
+Introduce a structure that can track relocations that cross the range of
+VMAs of EBB and use it to only check relocations relevant to current EBB
+in check_section_ebb_pcrels_fit.
+It takes O(N log N) operations to build it and O(N) operations to move
+current EBB VMA window through its entire range, where N is the number
+of relocations in a section. The resulting complexity of
+compute_text_actions is thus reduced from O(N^2) to O(N log N + N * M),
+where M is the average number of relocations crossing each EBB.
+
+Original profile:
+
+% time self children called name
+-----------------------------------------
+ 44.26 71.53 6429/6429 compute_text_actions
+ 50.2 44.26 71.53 6429 check_section_ebb_pcrels_fit
+ 1.16 20.12 347506666/347576152 pcrel_reloc_fits
+ 2.95 16.52 347506666/348104944 get_relocation_opnd
+ 2.01 9.74 347575100/361252208 r_reloc_init
+ 0.55 7.53 347575100/363381467 r_reloc_get_section
+ 5.76 0.02 695013332/695013332 xlate_offset_with_removed_text
+ 0.68 3.89 347575100/363483827 bfd_octets_per_byte
+ 0.32 0.00 347506666/349910253 is_alt_relocation
+ 0.18 0.11 6391/6391 build_xlate_map
+ 0.00 0.00 6429/19417168 get_xtensa_relax_info
+ 0.00 0.00 6391/6391 free_xlate_map
+-----------------------------------------
+
+Same data, after optimization:
+
+% time self children called name
+-----------------------------------------
+ 2.56 3.08 6429/6429 compute_text_actions
+ 8.2 2.56 3.08 6429 check_section_ebb_pcrels_fit
+ 0.08 0.91 17721075/17790561 pcrel_reloc_fits
+ 0.17 0.47 17721075/31685977 r_reloc_init
+ 0.43 0.00 35442150/35442150 xlate_offset_with_removed_text
+ 0.02 0.37 17721075/33815236 r_reloc_get_section
+ 0.22 0.11 6391/6391 build_xlate_map
+ 0.05 0.22 17721075/33917596 bfd_octets_per_byte
+ 0.03 0.00 17721075/20405299 is_alt_relocation
+ 0.01 0.00 6429/6429 reloc_range_list_update_range
+ 0.00 0.00 6429/19417168 get_xtensa_relax_info
+ 0.00 0.00 6391/6391 free_xlate_map
+-----------------------------------------
+
+2015-04-01 Max Filippov <jcmvbkbc@gmail.com>
+bfd/
+ * elf32-xtensa.c (reloc_range_list, reloc_range_list_entry,
+ reloc_range): new typedef.
+ (reloc_range_list_struct, reloc_range_list_entry_struct,
+ reloc_range_struct): new structures.
+ (reloc_range_compare, build_reloc_ranges,
+ reloc_range_list_append, reloc_range_list_remove,
+ reloc_range_list_update_range, free_reloc_range_list): new
+ functions.
+ (compute_text_actions): precompute relocation opcodes before the
+ loop. Add relevant_relocs variable, initialize it before the
+ loop, pass it to the check_section_ebb_pcrels_fit.
+ (check_section_ebb_pcrels_fit): add new parameter:
+ relevant_relocs. Update address range in the relevant_relocs if
+ it's non-NULL and iterate only over relevant relocations.
+
+Backported from: b2b326d246f839ee218192ac88da2384d929a072
+Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
+---
+ bfd/elf32-xtensa.c | 321 +++++++++++++++++++++++++++++++++++++++++++++++++----
+ 1 file changed, 298 insertions(+), 23 deletions(-)
+
+diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
+index 0b6f584..872370b 100644
+--- a/bfd/elf32-xtensa.c
++++ b/bfd/elf32-xtensa.c
+@@ -6619,8 +6619,10 @@ static bfd_boolean compute_text_actions
+ (bfd *, asection *, struct bfd_link_info *);
+ static bfd_boolean compute_ebb_proposed_actions (ebb_constraint *);
+ static bfd_boolean compute_ebb_actions (ebb_constraint *);
++typedef struct reloc_range_list_struct reloc_range_list;
+ static bfd_boolean check_section_ebb_pcrels_fit
+- (bfd *, asection *, bfd_byte *, Elf_Internal_Rela *, const ebb_constraint *,
++ (bfd *, asection *, bfd_byte *, Elf_Internal_Rela *,
++ reloc_range_list *, const ebb_constraint *,
+ const xtensa_opcode *);
+ static bfd_boolean check_section_ebb_reduces (const ebb_constraint *);
+ static void text_action_add_proposed
+@@ -7219,6 +7221,221 @@ build_reloc_opcodes (bfd *abfd,
+ return reloc_opcodes;
+ }
+
++struct reloc_range_struct
++{
++ bfd_vma addr;
++ bfd_boolean add; /* TRUE if start of a range, FALSE otherwise. */
++ /* Original irel index in the array of relocations for a section. */
++ unsigned irel_index;
++};
++typedef struct reloc_range_struct reloc_range;
++
++typedef struct reloc_range_list_entry_struct reloc_range_list_entry;
++struct reloc_range_list_entry_struct
++{
++ reloc_range_list_entry *next;
++ reloc_range_list_entry *prev;
++ Elf_Internal_Rela *irel;
++ xtensa_opcode opcode;
++ int opnum;
++};
++
++struct reloc_range_list_struct
++{
++ /* The rest of the structure is only meaningful when ok is TRUE. */
++ bfd_boolean ok;
++
++ unsigned n_range; /* Number of range markers. */
++ reloc_range *range; /* Sorted range markers. */
++
++ unsigned first; /* Index of a first range element in the list. */
++ unsigned last; /* One past index of a last range element in the list. */
++
++ unsigned n_list; /* Number of list elements. */
++ reloc_range_list_entry *reloc; /* */
++ reloc_range_list_entry list_root;
++};
++
++static int
++reloc_range_compare (const void *a, const void *b)
++{
++ const reloc_range *ra = a;
++ const reloc_range *rb = b;
++
++ if (ra->addr != rb->addr)
++ return ra->addr < rb->addr ? -1 : 1;
++ if (ra->add != rb->add)
++ return ra->add ? -1 : 1;
++ return 0;
++}
++
++static void
++build_reloc_ranges (bfd *abfd, asection *sec,
++ bfd_byte *contents,
++ Elf_Internal_Rela *internal_relocs,
++ xtensa_opcode *reloc_opcodes,
++ reloc_range_list *list)
++{
++ unsigned i;
++ size_t n = 0;
++ size_t max_n = 0;
++ reloc_range *ranges = NULL;
++ reloc_range_list_entry *reloc =
++ bfd_malloc (sec->reloc_count * sizeof (*reloc));
++
++ memset (list, 0, sizeof (*list));
++ list->ok = TRUE;
++
++ for (i = 0; i < sec->reloc_count; i++)
++ {
++ Elf_Internal_Rela *irel = &internal_relocs[i];
++ int r_type = ELF32_R_TYPE (irel->r_info);
++ reloc_howto_type *howto = &elf_howto_table[r_type];
++ r_reloc r_rel;
++
++ if (r_type == R_XTENSA_ASM_SIMPLIFY
++ || r_type == R_XTENSA_32_PCREL
++ || !howto->pc_relative)
++ continue;
++
++ r_reloc_init (&r_rel, abfd, irel, contents,
++ bfd_get_section_limit (abfd, sec));
++
++ if (r_reloc_get_section (&r_rel) != sec)
++ continue;
++
++ if (n + 2 > max_n)
++ {
++ max_n = (max_n + 2) * 2;
++ ranges = bfd_realloc (ranges, max_n * sizeof (*ranges));
++ }
++
++ ranges[n].addr = irel->r_offset;
++ ranges[n + 1].addr = r_rel.target_offset;
++
++ ranges[n].add = ranges[n].addr < ranges[n + 1].addr;
++ ranges[n + 1].add = !ranges[n].add;
++
++ ranges[n].irel_index = i;
++ ranges[n + 1].irel_index = i;
++
++ n += 2;
++
++ reloc[i].irel = irel;
++
++ /* Every relocation won't possibly be checked in the optimized version of
++ check_section_ebb_pcrels_fit, so this needs to be done here. */
++ if (is_alt_relocation (ELF32_R_TYPE (irel->r_info)))
++ {
++ /* None of the current alternate relocs are PC-relative,
++ and only PC-relative relocs matter here. */
++ }
++ else
++ {
++ xtensa_opcode opcode;
++ int opnum;
++
++ if (reloc_opcodes)
++ opcode = reloc_opcodes[i];
++ else
++ opcode = get_relocation_opcode (abfd, sec, contents, irel);
++
++ if (opcode == XTENSA_UNDEFINED)
++ {
++ list->ok = FALSE;
++ break;
++ }
++
++ opnum = get_relocation_opnd (opcode, ELF32_R_TYPE (irel->r_info));
++ if (opnum == XTENSA_UNDEFINED)
++ {
++ list->ok = FALSE;
++ break;
++ }
++
++ /* Record relocation opcode and opnum as we've calculated them
++ anyway and they won't change. */
++ reloc[i].opcode = opcode;
++ reloc[i].opnum = opnum;
++ }
++ }
++
++ if (list->ok)
++ {
++ ranges = bfd_realloc (ranges, n * sizeof (*ranges));
++ qsort (ranges, n, sizeof (*ranges), reloc_range_compare);
++
++ list->n_range = n;
++ list->range = ranges;
++ list->reloc = reloc;
++ list->list_root.prev = &list->list_root;
++ list->list_root.next = &list->list_root;
++ }
++ else
++ {
++ free (ranges);
++ free (reloc);
++ }
++}
++
++static void reloc_range_list_append (reloc_range_list *list,
++ unsigned irel_index)
++{
++ reloc_range_list_entry *entry = list->reloc + irel_index;
++
++ entry->prev = list->list_root.prev;
++ entry->next = &list->list_root;
++ entry->prev->next = entry;
++ entry->next->prev = entry;
++ ++list->n_list;
++}
++
++static void reloc_range_list_remove (reloc_range_list *list,
++ unsigned irel_index)
++{
++ reloc_range_list_entry *entry = list->reloc + irel_index;
++
++ entry->next->prev = entry->prev;
++ entry->prev->next = entry->next;
++ --list->n_list;
++}
++
++/* Update relocation list object so that it lists all relocations that cross
++ [first; last] range. Range bounds should not decrease with successive
++ invocations. */
++static void reloc_range_list_update_range (reloc_range_list *list,
++ bfd_vma first, bfd_vma last)
++{
++ /* This should not happen: EBBs are iterated from lower addresses to higher.
++ But even if that happens there's no need to break: just flush current list
++ and start from scratch. */
++ if ((list->last > 0 && list->range[list->last - 1].addr > last) ||
++ (list->first > 0 && list->range[list->first - 1].addr >= first))
++ {
++ list->first = 0;
++ list->last = 0;
++ list->n_list = 0;
++ list->list_root.next = &list->list_root;
++ list->list_root.prev = &list->list_root;
++ fprintf (stderr, "%s: move backwards requested\n", __func__);
++ }
++
++ for (; list->last < list->n_range &&
++ list->range[list->last].addr <= last; ++list->last)
++ if (list->range[list->last].add)
++ reloc_range_list_append (list, list->range[list->last].irel_index);
++
++ for (; list->first < list->n_range &&
++ list->range[list->first].addr < first; ++list->first)
++ if (!list->range[list->first].add)
++ reloc_range_list_remove (list, list->range[list->first].irel_index);
++}
++
++static void free_reloc_range_list (reloc_range_list *list)
++{
++ free (list->range);
++ free (list->reloc);
++}
+
+ /* The compute_text_actions function will build a list of potential
+ transformation actions for code in the extended basic block of each
+@@ -7245,6 +7462,7 @@ compute_text_actions (bfd *abfd,
+ property_table_entry *prop_table = 0;
+ int ptblsize = 0;
+ bfd_size_type sec_size;
++ reloc_range_list relevant_relocs;
+
+ relax_info = get_xtensa_relax_info (sec);
+ BFD_ASSERT (relax_info);
+@@ -7277,6 +7495,12 @@ compute_text_actions (bfd *abfd,
+ goto error_return;
+ }
+
++ /* Precompute the opcode for each relocation. */
++ reloc_opcodes = build_reloc_opcodes (abfd, sec, contents, internal_relocs);
++
++ build_reloc_ranges (abfd, sec, contents, internal_relocs, reloc_opcodes,
++ &relevant_relocs);
++
+ for (i = 0; i < sec->reloc_count; i++)
+ {
+ Elf_Internal_Rela *irel = &internal_relocs[i];
+@@ -7340,17 +7564,13 @@ compute_text_actions (bfd *abfd,
+ ebb->start_reloc_idx = i;
+ ebb->end_reloc_idx = i;
+
+- /* Precompute the opcode for each relocation. */
+- if (reloc_opcodes == NULL)
+- reloc_opcodes = build_reloc_opcodes (abfd, sec, contents,
+- internal_relocs);
+-
+ if (!extend_ebb_bounds (ebb)
+ || !compute_ebb_proposed_actions (&ebb_table)
+ || !compute_ebb_actions (&ebb_table)
+ || !check_section_ebb_pcrels_fit (abfd, sec, contents,
+- internal_relocs, &ebb_table,
+- reloc_opcodes)
++ internal_relocs,
++ &relevant_relocs,
++ &ebb_table, reloc_opcodes)
+ || !check_section_ebb_reduces (&ebb_table))
+ {
+ /* If anything goes wrong or we get unlucky and something does
+@@ -7372,6 +7592,8 @@ compute_text_actions (bfd *abfd,
+ free_ebb_constraint (&ebb_table);
+ }
+
++ free_reloc_range_list (&relevant_relocs);
++
+ #if DEBUG
+ if (relax_info->action_list.head)
+ print_action_list (stderr, &relax_info->action_list);
+@@ -7974,14 +8196,17 @@ check_section_ebb_pcrels_fit (bfd *abfd,
+ asection *sec,
+ bfd_byte *contents,
+ Elf_Internal_Rela *internal_relocs,
++ reloc_range_list *relevant_relocs,
+ const ebb_constraint *constraint,
+ const xtensa_opcode *reloc_opcodes)
+ {
+ unsigned i, j;
++ unsigned n = sec->reloc_count;
+ Elf_Internal_Rela *irel;
+ xlate_map_t *xmap = NULL;
+ bfd_boolean ok = TRUE;
+ xtensa_relax_info *relax_info;
++ reloc_range_list_entry *entry = NULL;
+
+ relax_info = get_xtensa_relax_info (sec);
+
+@@ -7992,7 +8217,40 @@ check_section_ebb_pcrels_fit (bfd *abfd,
+ can still be used. */
+ }
+
+- for (i = 0; i < sec->reloc_count; i++)
++ if (relevant_relocs && constraint->action_count)
++ {
++ if (!relevant_relocs->ok)
++ {
++ ok = FALSE;
++ n = 0;
++ }
++ else
++ {
++ bfd_vma min_offset, max_offset;
++ min_offset = max_offset = constraint->actions[0].offset;
++
++ for (i = 1; i < constraint->action_count; ++i)
++ {
++ proposed_action *action = &constraint->actions[i];
++ bfd_vma offset = action->offset;
++
++ if (offset < min_offset)
++ min_offset = offset;
++ if (offset > max_offset)
++ max_offset = offset;
++ }
++ reloc_range_list_update_range (relevant_relocs, min_offset,
++ max_offset);
++ n = relevant_relocs->n_list;
++ entry = &relevant_relocs->list_root;
++ }
++ }
++ else
++ {
++ relevant_relocs = NULL;
++ }
++
++ for (i = 0; i < n; i++)
+ {
+ r_reloc r_rel;
+ bfd_vma orig_self_offset, orig_target_offset;
+@@ -8001,7 +8259,15 @@ check_section_ebb_pcrels_fit (bfd *abfd,
+ reloc_howto_type *howto;
+ int self_removed_bytes, target_removed_bytes;
+
+- irel = &internal_relocs[i];
++ if (relevant_relocs)
++ {
++ entry = entry->next;
++ irel = entry->irel;
++ }
++ else
++ {
++ irel = internal_relocs + i;
++ }
+ r_type = ELF32_R_TYPE (irel->r_info);
+
+ howto = &elf_howto_table[r_type];
+@@ -8067,21 +8333,30 @@ check_section_ebb_pcrels_fit (bfd *abfd,
+ xtensa_opcode opcode;
+ int opnum;
+
+- if (reloc_opcodes)
+- opcode = reloc_opcodes[i];
+- else
+- opcode = get_relocation_opcode (abfd, sec, contents, irel);
+- if (opcode == XTENSA_UNDEFINED)
++ if (relevant_relocs)
+ {
+- ok = FALSE;
+- break;
++ opcode = entry->opcode;
++ opnum = entry->opnum;
+ }
+-
+- opnum = get_relocation_opnd (opcode, ELF32_R_TYPE (irel->r_info));
+- if (opnum == XTENSA_UNDEFINED)
++ else
+ {
+- ok = FALSE;
+- break;
++ if (reloc_opcodes)
++ opcode = reloc_opcodes[relevant_relocs ?
++ (unsigned)(entry - relevant_relocs->reloc) : i];
++ else
++ opcode = get_relocation_opcode (abfd, sec, contents, irel);
++ if (opcode == XTENSA_UNDEFINED)
++ {
++ ok = FALSE;
++ break;
++ }
++
++ opnum = get_relocation_opnd (opcode, ELF32_R_TYPE (irel->r_info));
++ if (opnum == XTENSA_UNDEFINED)
++ {
++ ok = FALSE;
++ break;
++ }
+ }
+
+ if (!pcrel_reloc_fits (opcode, opnum, self_offset, target_offset))
+@@ -8778,7 +9053,7 @@ move_shared_literal (asection *sec,
+ /* Check all of the PC-relative relocations to make sure they still fit. */
+ relocs_fit = check_section_ebb_pcrels_fit (target_sec->owner, target_sec,
+ target_sec_cache->contents,
+- target_sec_cache->relocs,
++ target_sec_cache->relocs, NULL,
+ &ebb_table, NULL);
+
+ if (!relocs_fit)
+--
+1.8.1.4
+
Code Review / packages / trusty / cirros-testvm.git / blobdiff