PR25333, GAS is slow processing -fdebug-types-sections
Alan Modra
amodra@gmail.com
Sat Feb 24 04:28:11 GMT 2024
gas needs to build lists of sections for each group. This arranges to
build the lists earlier, so they can be used when looking for sections
that belong to a group. Using the section hash table to find sections
by name, then by group isn't efficient when there are numerous groups
with the same section names. Using a hash table to quickly find a
group, then searching by section name on a list for the group results
in a 100-fold speed improvement assembling the testcase in this PR.
To reduce the number of times we traverse the section list, the patch
also moves some processing done in elf_adjust_symtab for linked-to
section, to elf_frob_file. This requires a testsuite change because
processing will stop before elf_frob_file if there is a parse error in
section21.s, ie. you'll only get the "junk at end of line" error, not
the "undefined linked-to symbol" errors.
PR 25333
* config/obj-elf.c (struct group_list, groups): Move earlier.
(match_section): New function, extracted from..
(get_section_by_match): ..here.
(free_section_idx): Move earlier.
(group_section_find, group_section_insert): New functions.
(change_section): Use the above.
(elf_set_group_name): New function.
(obj_elf_attach_to_group): Use elf_set_group_name.
(set_additional_section_info): Handle linked_to_symbol_name and
stabs code, extracted from..
(adjust_stab_sections): ..here,..
(build_additional_section_info): ..and here.
(elf_adjust_symtab): Don't call build_additional_section_info.
(elf_frob_file): Adjust.
* config/obj-elf.h (elf_set_group_name): Declare.
* config/tc-xtensa.c (cache_literal_section): Use elf_set_group_name.
(xtensa_make_property_section): Likewise.
* testsuite/gas/elf/attach-1.d: Stricter group section matching,
and changed group section ordering.
* testsuite/gas/elf/attach-2.d: Stricter group section matching.
* testsuite/gas/elf/attach-2.s: Provide section bar type.
* testsuite/gas/elf/elf.exp: Run attach-2.
* testsuite/gas/elf/section21.l: Update.
* testsuite/gas/elf/section21.s: Don't check for a parse error.
diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c
index 00c6e38acf9..e28ba0a62d5 100644
--- a/gas/config/obj-elf.c
+++ b/gas/config/obj-elf.c
@@ -493,16 +493,19 @@ static struct section_stack *section_stack;
/* ELF section flags for unique sections. */
#define SEC_ASSEMBLER_SHF_MASK SHF_GNU_RETAIN
-/* Return TRUE iff SEC matches the section info INF. */
+struct group_list
+{
+ asection **head; /* Section lists. */
+ unsigned int num_group; /* Number of lists. */
+ htab_t indexes; /* Maps group name to index in head array. */
+};
+
+static struct group_list groups;
static bool
-get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
+match_section (const asection *sec, const struct elf_section_match *match)
{
- struct elf_section_match *match = (struct elf_section_match *) inf;
- const char *gname = match->group_name;
- const char *group_name = elf_group_name (sec);
- const char *linked_to_symbol_name
- = sec->map_head.linked_to_symbol_name;
+ const char *linked_to_symbol_name = sec->map_head.linked_to_symbol_name;
unsigned int sh_info = elf_section_data (sec)->this_hdr.sh_info;
bfd_vma sh_flags = (elf_section_data (sec)->this_hdr.sh_flags
& SEC_ASSEMBLER_SHF_MASK);
@@ -512,10 +515,6 @@ get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
&& ((bfd_section_flags (sec) & SEC_ASSEMBLER_SECTION_ID)
== (match->flags & SEC_ASSEMBLER_SECTION_ID))
&& sec->section_id == match->section_id
- && (group_name == gname
- || (group_name != NULL
- && gname != NULL
- && strcmp (group_name, gname) == 0))
&& (linked_to_symbol_name == match->linked_to_symbol_name
|| (linked_to_symbol_name != NULL
&& match->linked_to_symbol_name != NULL
@@ -523,6 +522,93 @@ get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
match->linked_to_symbol_name) == 0)));
}
+/* Return TRUE iff SEC matches the section info INF. */
+
+static bool
+get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
+{
+ struct elf_section_match *match = (struct elf_section_match *) inf;
+ const char *gname = match->group_name;
+ const char *group_name = elf_group_name (sec);
+
+ return ((group_name == gname
+ || (group_name != NULL
+ && gname != NULL
+ && strcmp (group_name, gname) == 0))
+ && match_section (sec, match));
+}
+
+static void
+free_section_idx (void *ent)
+{
+ string_tuple_t *tuple = ent;
+ free ((char *) tuple->value);
+}
+
+/* Go look in section lists kept per group for SEC_NAME with
+ properties given by MATCH. If info for the group named by
+ MATCH->GROUP_NAME has been initialised, set GROUP_IDX. */
+
+static asection *
+group_section_find (const struct elf_section_match *match,
+ const char *sec_name,
+ unsigned int **group_idx)
+{
+ if (!groups.indexes)
+ {
+ groups.num_group = 0;
+ groups.head = NULL;
+ groups.indexes = htab_create_alloc (16, hash_string_tuple, eq_string_tuple,
+ free_section_idx, notes_calloc, NULL);
+ *group_idx = NULL;
+ return NULL;
+ }
+
+ *group_idx = str_hash_find (groups.indexes, match->group_name);
+ if (*group_idx == NULL)
+ return NULL;
+
+ asection *s;
+ for (s = groups.head[**group_idx]; s != NULL; s = elf_next_in_group (s))
+ if ((s->name == sec_name
+ || strcmp (s->name, sec_name) == 0)
+ && match_section (s, match))
+ break;
+ return s;
+}
+
+/* Insert SEC into section lists kept per group. MATCH and GROUP_IDX
+ must be from a prior call to group_section_find. */
+
+static void
+group_section_insert (const struct elf_section_match *match,
+ asection *sec,
+ unsigned int **group_idx)
+{
+ if (*group_idx != NULL)
+ {
+ elf_next_in_group (sec) = groups.head[**group_idx];
+ groups.head[**group_idx] = sec;
+ return;
+ }
+
+ unsigned int i = groups.num_group;
+ if ((i & 127) == 0)
+ groups.head = XRESIZEVEC (asection *, groups.head, i + 128);
+ groups.head[i] = sec;
+ groups.num_group += 1;
+
+ /* We keep the index into groups.head rather than the entry address
+ because groups.head may be realloc'd, and because str_hash values
+ are a void* we make a copy of the index. Strictly speaking there
+ is no guarantee that void* can represent any int value, so doing
+ without the indirection by casting an int or even uintptr_t may
+ for example lose lsbs of the value. */
+ unsigned int *idx_ptr = XNEW (unsigned int);
+ *idx_ptr = i;
+ str_hash_insert (groups.indexes, match->group_name, idx_ptr, 0);
+}
+
/* Handle the .section pseudo-op. This code supports two different
syntaxes.
@@ -582,15 +668,23 @@ change_section (const char *name,
obj_elf_section_change_hook ();
- old_sec = bfd_get_section_by_name_if (stdoutput, name, get_section_by_match,
- (void *) match_p);
+ unsigned int *group_idx = NULL;
+ if (match_p->group_name)
+ old_sec = group_section_find (match_p, name, &group_idx);
+ else
+ old_sec = bfd_get_section_by_name_if (stdoutput, name, get_section_by_match,
+ (void *) match_p);
if (old_sec)
{
sec = old_sec;
subseg_set (sec, new_subsection);
}
else
- sec = subseg_force_new (name, new_subsection);
+ {
+ sec = subseg_force_new (name, new_subsection);
+ if (match_p->group_name)
+ group_section_insert (match_p, sec, &group_idx);
+ }
bed = get_elf_backend_data (stdoutput);
ssect = (*bed->get_sec_type_attr) (stdoutput, sec);
@@ -1084,6 +1178,29 @@ obj_elf_section_name (void)
return name;
}
+/* Arrange to put SEC, known to be in group GNAME into the per-group
+ section lists kept by gas. */
+
+void
+elf_set_group_name (asection *sec, const char *gname)
+{
+ elf_group_name (sec) = gname;
+ elf_section_flags (sec) |= SHF_GROUP;
+
+ struct elf_section_match match;
+ match.group_name = gname;
+ match.linked_to_symbol_name = sec->map_head.linked_to_symbol_name;
+ match.section_id = sec->section_id;
+ match.sh_info = elf_section_data (sec)->this_hdr.sh_info;
+ match.sh_flags = (elf_section_data (sec)->this_hdr.sh_flags
+ & SEC_ASSEMBLER_SHF_MASK);
+ match.flags = bfd_section_flags (sec) & SEC_ASSEMBLER_SECTION_ID;
+
+ unsigned int *group_idx;
+ if (!group_section_find (&match, sec->name, &group_idx))
+ group_section_insert (&match, sec, &group_idx);
+}
+
static void
obj_elf_attach_to_group (int dummy ATTRIBUTE_UNUSED)
{
@@ -1102,9 +1219,7 @@ obj_elf_attach_to_group (int dummy ATTRIBUTE_UNUSED)
bfd_section_name (now_seg), elf_group_name (now_seg));
return;
}
-
- elf_group_name (now_seg) = gname;
- elf_section_flags (now_seg) |= SHF_GROUP;
+ elf_set_group_name (now_seg, gname);
}
void
@@ -2588,11 +2703,27 @@ obj_elf_init_stab_section (segT stab, segT stabstr)
#endif
-/* Fill in the counts in the first entry in a .stabs section. */
+/* Called via bfd_map_over_sections. If SEC's linked_to_symbol_name
+ isn't NULL, set up its linked-to section.
+ For .stabs section, fill in the counts in the first entry. */
static void
-adjust_stab_sections (bfd *abfd, asection *sec, void *xxx ATTRIBUTE_UNUSED)
+set_additional_section_info (bfd *abfd,
+ asection *sec,
+ void *inf ATTRIBUTE_UNUSED)
{
+ if (sec->map_head.linked_to_symbol_name)
+ {
+ symbolS *linked_to_sym;
+ linked_to_sym = symbol_find (sec->map_head.linked_to_symbol_name);
+ if (!linked_to_sym || !S_IS_DEFINED (linked_to_sym))
+ as_bad (_("undefined linked-to symbol `%s' on section `%s'"),
+ sec->map_head.linked_to_symbol_name,
+ bfd_section_name (sec));
+ else
+ elf_linked_to_section (sec) = S_GET_SEGMENT (linked_to_sym);
+ }
+
char *name;
asection *strsec;
char *p;
@@ -2811,80 +2942,6 @@ elf_fixup_removed_symbol (symbolS **sympp)
*sympp = symp;
}
-struct group_list
-{
- asection **head; /* Section lists. */
- unsigned int num_group; /* Number of lists. */
- htab_t indexes; /* Maps group name to index in head array. */
-};
-
-static struct group_list groups;
-
-/* Called via bfd_map_over_sections. If SEC is a member of a group,
- add it to a list of sections belonging to the group. INF is a
- pointer to a struct group_list, which is where we store the head of
- each list. If its link_to_symbol_name isn't NULL, set up its
- linked-to section. */
-
-static void
-build_additional_section_info (bfd *abfd ATTRIBUTE_UNUSED,
- asection *sec, void *inf)
-{
- struct group_list *list = (struct group_list *) inf;
- const char *group_name = elf_group_name (sec);
- unsigned int i;
- unsigned int *elem_idx;
- unsigned int *idx_ptr;
-
- if (sec->map_head.linked_to_symbol_name)
- {
- symbolS *linked_to_sym;
- linked_to_sym = symbol_find (sec->map_head.linked_to_symbol_name);
- if (!linked_to_sym || !S_IS_DEFINED (linked_to_sym))
- as_bad (_("undefined linked-to symbol `%s' on section `%s'"),
- sec->map_head.linked_to_symbol_name,
- bfd_section_name (sec));
- else
- elf_linked_to_section (sec) = S_GET_SEGMENT (linked_to_sym);
- }
-
- if (group_name == NULL)
- return;
-
- /* If this group already has a list, add the section to the head of
- the list. */
- elem_idx = (unsigned int *) str_hash_find (list->indexes, group_name);
- if (elem_idx != NULL)
- {
- elf_next_in_group (sec) = list->head[*elem_idx];
- list->head[*elem_idx] = sec;
- return;
- }
-
- /* New group. Make the arrays bigger in chunks to minimize calls to
- realloc. */
- i = list->num_group;
- if ((i & 127) == 0)
- {
- unsigned int newsize = i + 128;
- list->head = XRESIZEVEC (asection *, list->head, newsize);
- }
- list->head[i] = sec;
- list->num_group += 1;
-
- /* Add index to hash. */
- idx_ptr = XNEW (unsigned int);
- *idx_ptr = i;
- str_hash_insert (list->indexes, group_name, idx_ptr, 0);
-}
-
-static void
-free_section_idx (void *ent)
-{
- string_tuple_t *tuple = ent;
- free ((char *) tuple->value);
-}
-
/* Create symbols for group signature. */
void
@@ -2892,14 +2949,6 @@ elf_adjust_symtab (void)
{
unsigned int i;
- /* Go find section groups. */
- groups.num_group = 0;
- groups.head = NULL;
- groups.indexes = htab_create_alloc (16, hash_string_tuple, eq_string_tuple,
- free_section_idx, notes_calloc, NULL);
- bfd_map_over_sections (stdoutput, build_additional_section_info,
- &groups);
-
/* Make the SHT_GROUP sections that describe each section group. We
can't set up the section contents here yet, because elf section
indices have yet to be calculated. elf.c:set_group_contents does
@@ -2966,7 +3015,7 @@ elf_adjust_symtab (void)
void
elf_frob_file (void)
{
- bfd_map_over_sections (stdoutput, adjust_stab_sections, NULL);
+ bfd_map_over_sections (stdoutput, set_additional_section_info, NULL);
#ifdef elf_tc_final_processing
elf_tc_final_processing ();
diff --git a/gas/config/obj-elf.h b/gas/config/obj-elf.h
index 0187f6ebfad..7b5d2fe2b80 100644
--- a/gas/config/obj-elf.h
+++ b/gas/config/obj-elf.h
@@ -297,4 +297,6 @@ extern asection *elf_com_section_ptr;
extern symbolS * elf_common_parse (int ignore ATTRIBUTE_UNUSED, symbolS *symbolP,
addressT size);
+extern void elf_set_group_name (asection *, const char *);
+
#endif /* _OBJ_ELF_H */
diff --git a/gas/config/tc-xtensa.c b/gas/config/tc-xtensa.c
index 188715d9619..e051bb9265b 100644
--- a/gas/config/tc-xtensa.c
+++ b/gas/config/tc-xtensa.c
@@ -11718,10 +11718,11 @@ cache_literal_section (bool use_abs_literals)
| (linkonce ? (SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD) : 0)
| (use_abs_literals ? SEC_DATA : SEC_CODE));
- elf_group_name (seg) = group_name;
-
bfd_set_section_flags (seg, flags);
bfd_set_section_alignment (seg, 2);
+
+ if (group_name)
+ elf_set_group_name (seg, group_name);
}
*pcached = seg;
@@ -11813,7 +11814,8 @@ xtensa_make_property_section (asection *sec, const char *base_name)
if (! prop_sec)
return 0;
- elf_group_name (prop_sec) = elf_group_name (sec);
+ if (elf_group_name (sec))
+ elf_set_group_name (prop_sec, elf_group_name (sec));
}
free (prop_sec_name);
diff --git a/gas/testsuite/gas/elf/attach-1.d b/gas/testsuite/gas/elf/attach-1.d
index 053783ea1a0..b6b76f5c234 100644
--- a/gas/testsuite/gas/elf/attach-1.d
+++ b/gas/testsuite/gas/elf/attach-1.d
@@ -3,9 +3,9 @@
#source: attach-1.s
#...
-group section \[ 1\] `\.group' \[foo\.group\] contains . sections:
+group section \[ 1\] `\.group' \[foo\.group\] contains [24] sections:
\[Index\] Name
- \[ .\] .*
- \[ .\] foo
-#pass
-
+.* foo
+.* (\.text|P)
+#?.* \.xt\.prop
+#?.* \.rela\.xt\.prop
diff --git a/gas/testsuite/gas/elf/attach-2.d b/gas/testsuite/gas/elf/attach-2.d
index 4aa52116357..68a1aab4c03 100644
--- a/gas/testsuite/gas/elf/attach-2.d
+++ b/gas/testsuite/gas/elf/attach-2.d
@@ -1,11 +1,11 @@
#readelf: --section-groups
-#name: Attaching a section to a non-existant group
+#name: Attaching a section to group defined later
#source: attach-2.s
#...
-group section \[ 1\] `\.group' \[foo\.group\] contains 2 sections:
+group section \[ 1\] `\.group' \[foo\.group\] contains [24] sections:
\[Index\] Name
- \[ .\] bar
- \[ .\] foo
-#pass
-
+.* bar
+.* foo
+#?.* \.xt\.prop
+#?.* \.rela\.xt\.prop
diff --git a/gas/testsuite/gas/elf/attach-2.s b/gas/testsuite/gas/elf/attach-2.s
index 4a5663f3872..d62a81b25fe 100644
--- a/gas/testsuite/gas/elf/attach-2.s
+++ b/gas/testsuite/gas/elf/attach-2.s
@@ -1,9 +1,9 @@
- .section bar
+ .section bar, "ax", %progbits
.nop
.attach_to_group foo.group
.section foo, "G", %note , foo.group
.word 0
- .section bar
+ .section bar, "ax", %progbits
.nop
diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index e03dc2bf00c..c828c3af25c 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -149,6 +149,7 @@ if { [is_elf_format] } then {
run_dump_test "group3"
run_dump_test "attach-1"
+ run_dump_test "attach-2"
run_dump_test "attach-err"
switch -glob $target_triplet {
diff --git a/gas/testsuite/gas/elf/section21.l b/gas/testsuite/gas/elf/section21.l
index 53f04151d33..b4d1283f312 100644
--- a/gas/testsuite/gas/elf/section21.l
+++ b/gas/testsuite/gas/elf/section21.l
@@ -1,5 +1,3 @@
[^:]*: Assembler messages:
-[^:]*:11: Error: junk at end of line, first unrecognized character is `f'
-#...
[^:]*: Error: undefined linked-to symbol `bar' on section `__patchable_function_entries'
[^:]*: Error: undefined linked-to symbol `foo' on section `__patchable_function_entries'
diff --git a/gas/testsuite/gas/elf/section21.s b/gas/testsuite/gas/elf/section21.s
index ae5f848b299..e874154e54e 100644
--- a/gas/testsuite/gas/elf/section21.s
+++ b/gas/testsuite/gas/elf/section21.s
@@ -2,14 +2,9 @@
.dc.a .LPFE1
.text
.LPFE1:
- .byte 0
+ .dc.a 0
.section __patchable_function_entries,"awo",%progbits,foo
.dc.a .LPFE2
.text
.LPFE2:
.dc.a foo
- .section __patchable_function_entries,"awo",%progbits,1foo
- .dc.a .LPFE3
- .text
-.LPFE3:
- .byte 0
--
Alan Modra
Australia Development Lab, IBM
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