Set non_ir_ref_regular to TRUE for symbols forced into the output file
so that they won't be removed by garbage collection with LTO.
PR ld/23309
* ldlang.c (insert_undefined): Set non_ir_ref_regular to TRUE.
* plugin.c (is_visible_from_outside): Don't scan entry_symbol.
* testsuite/ld-plugin/pr23309.c: New file.
* testsuite/ld-plugin/pr23309.d: Likewise.
Define a SEC_FIXED_SIZE section flag for target backends to use for
output sections whose size has been fixed in the psABI. The size of
such sections will not be changed anyhow by the generic linker and it is
up to the target backend to get their size right.
bfd/
* section.c (SEC_FIXED_SIZE): New macro.
* bfd-in2.h: Regenerate.
ld/
* ldlang.c (insert_pad): Do not change output section's size if
SEC_FIXED_SIZE is set in the flags.
(size_input_section): Likewise.
(lang_size_sections_1): Likewise.
(lang_reset_memory_regions): Likewise.
So what was happening was that the file added from libgcc.a during the
rescan was not put on file_chain. map_input_to_output_sections then
doesn't see the file and its sections are treated as discarded.
The file_chain list pointer bug was caused by that fact that an
archive element claimed by the plugin does not have my_archive set.
Or more correctly, the actual archive element does have my_archive
set, but this bfd is replaced with a dummy bfd that doesn't have
my_archive set.
PR 22751
* ldlang.c (find_rescan_insertion): Look past bfds with claim_archive
set.
In a linker script, a sequence like this:
foo = ADDR (.some_section);
bar = foo;
PROVIDE (foo = 0);
will result in 'bar = ADDR (.some_section)' and 'foo = 0', which seems
like incorrect behaviour, foo is clearly defined elsewhere, and so the
PROVIDE should not trigger.
The problem is that an expression like this:
foo = ADDR (.some_section);
can't be evaluated until a late phase of the linker, due to the need
for the section '.some_section' to have been placed, then the PROVIDE
was being marked as being used during an earlier phase. At the end of
the link, both lines:
foo = ADDR (.some_section);
PROVIDE (foo = 0);
are active, and this causes the final value of 'foo' to be 0.
The solution proposed in this commit is that, during earlier phases of
the linker, when we see the expression 'foo = ADDR (.some_section);',
instead of ignoring the expression, we create a "fake" definition of
'foo'. The existence of this "fake" definition prevents the PROVIDE
from being marked used, and during the final phase the real definition
of 'foo' will replace the "fake" definition.
The new test provide-6 covers the exact case described above. The
provide-7 test is similar to the above, but using constant
expressions, this was never broken, but is added here to increase
coverage.
The provide-8 case also didn't fail before this commit, but I did
manage to break this case during development of this patch. This case
was only covered by a mmix test before, so I've added this here to
increase coverage.
ld/ChangeLog:
* ldexp.c (exp_fold_tree_1): Rework condition underwhich provide
nodes are ignored in the tree walk, and move the location at which
we change provide nodes into provided nodes.
(exp_init_os): Add etree_provided.
* testsuite/ld-scripts/provide-6.d: New file.
* testsuite/ld-scripts/provide-6.t: New file.
* testsuite/ld-scripts/provide-7.d: New file.
* testsuite/ld-scripts/provide-7.t: New file.
* testsuite/ld-scripts/provide-8.d: New file.
* testsuite/ld-scripts/provide-8.t: New file.
This patch processes linker script assignment statements before ld
opens DT_NEEDED libraries, in order to define symbols like __bss_start
that might also be defined by a library, falsely triggering an error
about "DSO missing from command line".
The initial value won't be correct when assigning a symbol from dot,
and I make no attempt to handle all expressions. For example, an
assignment like "_start_foo = ADDR (.foo)" isn't valid until sections
are laid out, so won't define _start_foo early. What's here should be
enough for most common scripts, and hopefully won't perturb fragile
scripts.
bfd/
PR 22471
* elflink.c (_bfd_elf_merge_symbol): Allow weak symbols to override
early passes over linker script symbols.
* linker.c (_bfd_generic_link_add_one_symbol): Allow symbols to
override early passes over linker script symbols. Clear ldscript_def
on symbol definitions.
ld/
PR 22471
* ldexp.c (struct definedness_hash_entry): Delete "by_script". Make
"iteration" an 8-bit field, and update mask in all uses.
(definedness_newfunc): Don't init "by_script".
(update_definedness): Test ldscript_def rather than by_script.
(is_sym_value): Likewise.
(fold_name <DEFINED>): Return a result for first phase. Test
ldscript_def.
(fold_name <NAME>): Return a result for first phase.
* ldlang.c (open_input_bfds): Process all assignments, not just
defsym.
(lang_process): Increment lang_statement_iteration before
open_input_bfds.
* testsuite/ld-mips-elf/tlsdyn-o32-1.d: Adjust for larger .dynsym.
* testsuite/ld-mips-elf/tlsdyn-o32-1.got: Likewise.
* testsuite/ld-mips-elf/tlsdyn-o32-2.d: Likewise.
* testsuite/ld-mips-elf/tlsdyn-o32-2.got: Likewise.
* testsuite/ld-mips-elf/tlsdyn-o32-3.d: Likewise.
* testsuite/ld-mips-elf/tlsdyn-o32-3.got: Likewise.
Extract GNU_RELRO region check into a new funtion and pass a pointer to
seg_align_type to lang_find_relro_sections_1 so that they can also be
used for text-only LOAD segment.
* ldlang.c (lang_size_sections_1): Extract GNU_RELRO region check
into ...
(ldlang_check_relro_region): New function.
(lang_find_relro_sections_1): Add an argument for pointer to
seg_align_type and replace expld.dataseg with the pointer.
(lang_find_relro_sections): Pass address of expld.dataseg to
lang_find_relro_sections_1.
Break lang_size_sections down into separate functions so that they can
also be used for text-only LOAD segment. lang_size_relro_segment will
call lang_size_relro_segment_1 and lang_size_segment for both GNU_RELRO
segment and text-only LOAD segment.
* ldlang.c (lang_size_segment): New function.
(lang_size_relro_segment_1): Likewise.
(lang_size_relro_segment): Likewise.
(lang_size_sections): Rewrite to call lang_size_relro_segment.
Update GNU_RELRO date type so that they can also be used for text-only
LOAD segment.
* ldexp.h (phase_enum): Rename exp_dataseg_none,
exp_dataseg_align_seen, exp_dataseg_relro_seen,
exp_dataseg_end_seen, exp_dataseg_relro_adjust,
exp_dataseg_adjust and exp_dataseg_done to exp_seg_none,
exp_seg_align_seen, exp_seg_relro_seen, exp_seg_end_seen,
exp_seg_relro_adjust, exp_seg_adjust and exp_seg_done.
(relro_enum): Rename exp_dataseg_relro_none,
exp_dataseg_relro_start and exp_dataseg_relro_end to
exp_seg_relro_none, exp_seg_relro_start and exp_seg_relro_end.
(seg_align_type): New struct type.
(ldexp_control): Use seg_align_type.
* ldexp.c (fold_unary): Updated.
(fold_binary): Likewise.
* ldlang.c (strip_excluded_output_sections): Likewise.
(lang_size_sections_1): Likewise.
(lang_size_sections): Likewise.
ld ought to be more clever about where it puts LTO recompiled objects.
Ideally the recompiled objects ought to be ordered to the same place
their IR objects were, and files extracted from archives on the second
pass ought to go in the same place as they would if extracted on the
first pass. This patch addresses the archive problem. Without this
fix, objects extracted from archives might be placed after the crt
files intended to go at the end of an executable or shared library,
possibly causing exception handling failures.
* ldlang.h (lang_input_statement_type): Expand comments.
(LANG_FOR_EACH_INPUT_STATEMENT): Rewrite without casts.
* ldlang.c (lang_for_each_input_file): Likewise.
(load_symbols): Set usrdata for archives.
(find_rescan_insertion): New function.
(lang_process): Trim off and reinsert entries added to file chain
when rescanning archives for LTO.
* ldmain.c (add_archive_element): Set my_archive input_statement
next pointer to last element added.
When processing an orphan section we first call lang_place_orphans, this
function handles a few sections for which the behaviour is known COMMON
sections, or sections marked as SEC_EXCLUDE.
Any orphans that are not handled in lang_place_orphans are passed on to
ldlang_place_orphan, this is where we decide where to put the orphan,
and then call lang_add_section to perform the actual orphan placement.
We previously had a larger set of checks at the start of the function
lang_add_section to discard some sections that we _knew_ should not be
added into the output file, this was where .group sections (in a final
link) and .debug* sections (with --strip-debug) were dropped.
The problem with dropping these sections at the lang_add_section stage
is that a user might also be using --orphan-handling=error to prevent
orphans. If they are then they should not be get errors about sections
that we know will be discarded, and which are not mentioned in the
linker script.
The solution proposed in this patch is to move the "will this section be
discarded" check into a separate function, and use this in
lang_place_orphans to have the early discard phase discard sections that
we know should not be included in the output file.
ld/ChangeLog:
PR 21961
* ldlang.c (lang_discard_section_p): New function.
(lang_add_section): Checks moved out into new function, which is
now called.
(lang_place_orphans): Call lang_discard_section_p instead of
duplicating some of the checks from lang_add_section.
* testsuite/ld-elf/orphan-11.d: New file.
* testsuite/ld-elf/orphan-11.ld: New file.
* testsuite/ld-elf/orphan-11.s: New file.
* testsuite/ld-elf/orphan-12.d: New file.
* testsuite/ld-elf/orphan-12.s: New file.
When --no-define-common is used to build shared library, treat common
symbol as undefined so that common symbols that are referenced from a
shared library to be assigned addresses only in the main program. This
eliminates the unused duplicate space in the shared library, and also
prevents any possible confusion over resolving to the wrong duplicate
when there are many dynamic modules with specialized search paths for
runtime symbol resolution.
--no-define-common is only allowed when building a shared library.
bfd/
PR ld/21903:
* elflink.c (elf_link_add_object_symbols): Treat common symbol
as undefined for --no-define-common.
include/
PR ld/21903:
* bfdlink.h (bfd_link_info): Add inhibit_common_definition.
ld/
PR ld/21903:
* ld.h (command_line): Remove inhibit_common_definition.
* ldgram.y: Replace command_line.inhibit_common_definition with
link_info.inhibit_common_definition.
* ldlang.c (lang_common): Likewise.
* lexsup.c (parse_args): Likewise.
* ldmain.c (main): Only allow --no-define-common with -shared.
* testsuite/ld-elf/pr21903.s: New file.
* testsuite/ld-elf/pr21903a.d: Likewise.
* testsuite/ld-elf/pr21903b.d: Likewise.
* testsuite/ld-elf/pr21903c.d: Likewise.
* testsuite/ld-elf/pr21903d.d: Likewise.
* testsuite/ld-elf/pr21903e.d: Likewise.
* ldgram.y (ldgram_had_keep): Make static.
(ldgram_vers_current_lang): Likewise.
(filename_spec): New rule.
(input_section_spec_no_keep): Use filename_spec.
(wildcard_maybe_exclude): New rule.
(wildcard_spec): Rename to...
(section_name_spec): ...this.
(section_NAME_list): Rename to...
(section_name_list): ...this.
(section_name_spec): Simplifiy and use wildcard_maybe_exclude.
* ldlang.c (placed_commons): Delete.
(lang_add_wild): No longer set placed_commons.
(print_wild_statement): Use full names for SORT specifiers.
* testsuite/ld-scripts/align.exp: Run new tests.
* testsuite/ld-scripts/align3.d: New file.
* testsuite/ld-scripts/align3.t: New file.
* testsuite/ld-scripts/align4.d: New file.
* testsuite/ld-scripts/align4.t: New file.
* testsuite/ld-scripts/align5.d: New file.
* testsuite/ld-scripts/align5.t: New file.
* testsuite/ld-scripts/exclude-file-5.d: New file.
* testsuite/ld-scripts/exclude-file-5.map: New file.
* testsuite/ld-scripts/exclude-file-5.t: New file.
* testsuite/ld-scripts/exclude-file-6.d: New file.
* testsuite/ld-scripts/exclude-file-6.map: New file.
* testsuite/ld-scripts/exclude-file-6.t: New file.
* NEWS: Mention the changes.
__start_SECNAME and __stop_SECNAME shouldn't be defined for "ld -r".
* ldlang.c (lang_set_startof): Skip if config.build_constructors
is FALSE.
* testsuite/ld-elf/sizeofc.d: New file.
* testsuite/ld-elf/startofc.d: Likewise.
Currently, linker will define __start_SECNAME and __stop_SECNAME symbols
only for orphaned sections.
However, during garbage collection, ELF linker marks all sections with
references to __start_SECNAME and __stop_SECNAME symbols as used even
when section SECNAME isn't an orphaned section and linker won't define
__start_SECNAME nor __stop_SECNAME. And ELF linker stores the first
input section whose name matches __start_SECNAME or __stop_SECNAME in
u.undef.section for garbage collection. If these symbols are provided
in linker script, u.undef.section is set to the section where they will
defined by linker script, which leads to the incorrect output.
This patch changes linker to always define referenced __start_SECNAME and
__stop_SECNAME if the input section name is the same as the output section
name, which is always true for orphaned sections, and SECNAME is a C
identifier. Also __start_SECNAME and __stop_SECNAME symbols are marked
as hidden by ELF linker so that __start_SECNAME and __stop_SECNAME symbols
for section SECNAME in different modules are unique. For garbage
collection, ELF linker stores the first matched input section in the
unused vtable field.
bfd/
PR ld/20022
PR ld/21557
PR ld/21562
PR ld/21571
* elf-bfd.h (elf_link_hash_entry): Add start_stop. Change the
vtable field to a union.
(_bfd_elf_is_start_stop): Removed.
* elf32-i386.c (elf_i386_convert_load_reloc): Also check for
__start_SECNAME and __stop_SECNAME symbols.
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Likewise.
* elflink.c (_bfd_elf_is_start_stop): Removed.
(_bfd_elf_gc_mark_rsec): Check start_stop instead of calling
_bfd_elf_is_start_stop.
(elf_gc_propagate_vtable_entries_used): Skip __start_SECNAME and
__stop_SECNAME symbols. Updated.
(elf_gc_smash_unused_vtentry_relocs): Likewise.
(bfd_elf_gc_record_vtinherit): Likewise.
(bfd_elf_gc_record_vtentry): Likewise.
ld/
PR ld/20022
PR ld/21557
PR ld/21562
PR ld/21571
* ld.texinfo: Update __start_SECNAME/__stop_SECNAME symbols.
* ldlang.c (lang_insert_orphan): Move handling of __start_SECNAME
and __stop_SECNAME symbols to ...
(lang_set_startof): Here. Also define __start_SECNAME and
__stop_SECNAME for -Ur.
* emultempl/elf32.em (gld${EMULATION_NAME}_after_open): Mark
referenced __start_SECNAME and __stop_SECNAME symbols as hidden
and set start_stop for garbage collection.
* testsuite/ld-elf/pr21562a.d: New file.
* testsuite/ld-elf/pr21562a.s: Likewise.
* testsuite/ld-elf/pr21562a.t: Likewise.
* testsuite/ld-elf/pr21562b.d: Likewise.
* testsuite/ld-elf/pr21562b.s: Likewise.
* testsuite/ld-elf/pr21562b.t: Likewise.
* testsuite/ld-elf/pr21562c.d: Likewise.
* testsuite/ld-elf/pr21562c.t: Likewise.
* testsuite/ld-elf/pr21562d.d: Likewise.
* testsuite/ld-elf/pr21562d.t: Likewise.
* testsuite/ld-elf/pr21562e.d: Likewise.
* testsuite/ld-elf/pr21562f.d: Likewise.
* testsuite/ld-elf/pr21562g.d: Likewise.
* testsuite/ld-elf/pr21562h.d: Likewise.
* testsuite/ld-elf/pr21562i.d: Likewise.
* testsuite/ld-elf/pr21562j.d: Likewise.
* testsuite/ld-elf/pr21562k.d: Likewise.
* testsuite/ld-elf/pr21562l.d: Likewise.
* testsuite/ld-elf/pr21562m.d: Likewise.
* testsuite/ld-elf/pr21562n.d: Likewise.
* testsuite/ld-gc/pr20022.d: Likewise.
* testsuite/ld-gc/pr20022a.s: Likewise.
* testsuite/ld-gc/pr20022b.s: Likewise.
* testsuite/ld-gc/gc.exp: Run PR ld/20022 tests.
* testsuite/ld-gc/pr19161.d: Also accept local __start_SECNAME
symbol.
* testsuite/ld-gc/start.d: Likewise.
* testsuite/ld-x86-64/lea1a.d: Updated.
* testsuite/ld-x86-64/lea1b.d: Updated.
* testsuite/ld-x86-64/lea1d.d: Updated.
* testsuite/ld-x86-64/lea1e.d: Likewise.
This commit adds a new linker feature: the ability to resolve section
groups as part of a relocatable link.
Currently section groups are automatically resolved when performing a
final link, and are carried through when performing a relocatable link.
By carried through this means that one copy of each section group (from
all the copies that might be found in all the input files) is placed
into the output file. Sections that are part of a section group will
not match input section specifiers within a linker script and are
forcibly kept as separate sections.
There is a slight resemblance between section groups and common
section. Like section groups, common sections are carried through when
performing a relocatable link, and resolved (allocated actual space)
only at final link time.
However, with common sections there is an ability to force the linker to
allocate space for the common sections when performing a relocatable
link, there's currently no such ability for section groups.
This commit adds such a mechanism. This new facility can be accessed in
two ways, first there's a command line switch --force-group-allocation,
second, there's a new linker script command FORCE_GROUP_ALLOCATION. If
one of these is used when performing a relocatable link then the linker
will resolve the section groups as though it were performing a final
link, the section group will be deleted, and the members of the group
will be placed like normal input sections. If there are multiple copies
of the group (from multiple input files) then only one copy of the group
members will be placed, the duplicate copies will be discarded.
Unlike common sections that have the --no-define-common command line
flag, and INHIBIT_COMMON_ALLOCATION linker script command there is no
way to prevent group resolution during a final link, this is because the
ELF gABI specifically prohibits the presence of SHT_GROUP sections in a
fully linked executable. However, the code as written should make
adding such a feature trivial, setting the new resolve_section_groups
flag to false during a final link should work as you'd expect.
bfd/ChangeLog:
* elf.c (_bfd_elf_make_section_from_shdr): Don't initially mark
SEC_GROUP sections as SEC_EXCLUDE.
(bfd_elf_set_group_contents): Replace use of abort with an assert.
(assign_section_numbers): Use resolve_section_groups flag instead
of relocatable link type.
(_bfd_elf_init_private_section_data): Use resolve_section_groups
flag instead of checking the final_link flag for part of the
checks in here. Fix white space as a result.
* elflink.c (elf_link_input_bfd): Use resolve_section_groups flag
instead of relocatable link type.
(bfd_elf_final_link): Likewise.
include/ChangeLog:
* bfdlink.h (struct bfd_link_info): Add new resolve_section_groups
flag.
ld/ChangeLog:
* ld.h (struct args_type): Add force_group_allocation field.
* ldgram.y: Add support for FORCE_GROUP_ALLOCATION.
* ldlex.h: Likewise.
* ldlex.l: Likewise.
* lexsup.c: Likewise.
* ldlang.c (unique_section_p): Check resolve_section_groups flag
not the relaxable link flag.
(lang_add_section): Discard section groups when we're resolving
groups. Clear the SEC_LINK_ONCE flag if we're resolving section
groups.
* ldmain.c (main): Initialise resolve_section_groups flag in
link_info based on command line flags.
* testsuite/ld-elf/group11.d: New file.
* testsuite/ld-elf/group12.d: New file.
* testsuite/ld-elf/group12.ld: New file.
* NEWS: Mention new features.
* ld.texinfo (Options): Document --force-group-allocation.
(Miscellaneous Commands): Document FORCE_GROUP_ALLOCATION.
PR ld/21251
* ldfile.c (ldfile_add_library_path): If the path starts with
$SYSROOT then use the sysroot as the real prefix.
* ldlang.c (lang_add_input_file): Treat $SYSROOT in the same
way as =.
* ldlex.l: Add $SYSROOT as allow prefix for a filename.
* ld.texinfo (-L): Document that $SYSROOT acts like = when
prefixing a library search path.
(INPUT): Likewise.
* testsuite/ld-scripts/sysroot-prefix.exp: Add $SYSROOT prefix
tests.
Complement commit 902e9fc76a ("PR ld/20828: Move symbol version
processing ahead of GC symbol sweep"), commit b531344c34 ("PR
ld/20828: Reorder the symbol sweep stage of section GC") and commit
81ff47b3a5 ("PR ld/20828: Fix linker script symbols wrongly forced
local with section GC"), and prevent symbols forcibly entered in the
output file with the use of the `--undefined=' or `--require-defined='
linker command line options or the EXTERN linker script command from
being swept in section garbage collection and consequently recorded in
the dynamic symbol table as local entries. This happens in certain
circumstances, where a symbol reference also exists in one of the static
input files, however only in a section which is garbage-collected and
does not make it to the output file, and the symbol is defined in a
dynamic object present in the link.
For example with the `i386-linux' target and the `pr21233.s' and
`pr21233-l.s' sources, and the `pr21233.ld' linker script included with
this change we get:
$ as -o pr21233-l.o pr21233-l.s
$ ld -shared -T pr21233.ld -o libpr21233.so pr21233-l.o
$ as -o pr21233.o pr21233.s
$ ld --gc-sections -e foo --require-defined=bar -T pr21233.ld -o pr21233 pr21233.o libpr21233.so
$ readelf --dyn-syms pr21233
Symbol table '.dynsym' contains 2 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 OBJECT LOCAL DEFAULT UND bar
$
which makes the run-time `bar' dependency of the `pr21233' executable
different from its corresponding link-time dependency, i.e. the presence
of `libpr21233.so' and its `bar' symbol is required at the link time,
however at the run time a copy of `libpr21233.so' without `bar' will do.
Similarly with `--undefined=' and EXTERN which do not actually require
the reference to the symbol requested to be satisfied with a definition
at the link time, however once the definition has been pulled at the
link time, so it should at the dynamic load time.
Additionally with the `mips-linux' target we get:
$ ld --gc-sections -e foo --require-defined=bar -T pr21233.ld -o pr21233 pr21233.o libpr21233.so
ld: BFD (GNU Binutils) 2.28.51.20170324 assertion fail .../bfd/elfxx-mips.c:3861
$
as the target is not prepared to handle such a local dynamic symbol.
With this change in effect we get:
$ readelf --dyn-syms pr21233
Symbol table '.dynsym' contains 2 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 OBJECT GLOBAL DEFAULT UND bar
$
instead, for both targets.
ld/
PR ld/21233
* ldlang.c (insert_undefined): Set `mark' for ELF symbols.
* testsuite/ld-elf/pr21233.sd: New test.
* testsuite/ld-elf/pr21233-l.sd: New test.
* testsuite/ld-elf/pr21233.ld: New test linker script.
* testsuite/ld-elf/pr21233-e.ld: New test linker script.
* testsuite/ld-elf/pr21233.s: New test source.
* testsuite/ld-elf/pr21233-l.s: New test source.
* testsuite/ld-elf/shared.exp: Run the new tests.
Since BFD64 may be used on 32-bit address, we need to apply addr_mask
to check VMA and LMA.
* ldlang.c (lang_check_section_addresses): Use addr_mask to
check VMA and LMA.
ld/
* ldlang.c (lang_check_section_addresses): Check for address space
overflow.
* testsuite/ld-checks/checks.exp (overflow_check): New procedure
* testsuite/ld-checks/over.s: New test source.
* testsuite/ld-checks/over.d: New test.
* testsuite/ld-checks/over2.s: New test source.
* testsuite/ld-checks/over2.d: New test.
Given a linker script fragment like this:
SECTIONS {
. = 0x1000;
.text : AT(0x100) { *(.text) }
.data : AT(0x200) { *(.data) }
.rodata : AT(0x300) { *(.rodata) }
}
and an input file containing sections, '.text', '.data.1', and
'.rodata', then we'd expect the linker to place '.text' and '.rodata' in
the obvious way, and the '.data.1' orphan section would be located after
the '.data' section (assuming similar section properties).
Further, I believe that the expectation would be that the LMA for the
orphan '.data.1' section would start from 0x200 (as there is no '.data'
content).
However, right now, the LMA for '.data.1' would be 0x101, following on
from the '.text' section, this is because the change in LMA for the
'.data' section is not noticed by the linker, if there's no content in
the '.data' section.
What can be even more confusing to a user (though the cause is obvious
once you understand what's going on) is that adding some content to
'.data' will cause the orphan '.data.1' to switch to an LMA based off of
0x200.
This commit changes the behaviour so that an empty section that is in
the default lma region, and sets its lma, will adjust the lma of the
default region, this change will then be reflected in following sections
within the default lma memory region.
There's a new test to cover this issue that passes on a range of
targets, however, some targets generate additional sections, or have
stricter memory region size requirements that make it harder to come
up with a generic pass pattern, that still tests the required
features. For now I've set the test to ignore these targets.
ld/ChangeLog:
* ldlang.c (lang_size_sections_1): Shortcut loop only after
tracking changes to the default regions LMA.
* testsuite/ld-elf/orphan-9.ld: Extend header comment.
* testsuite/ld-elf/orphan-10.d: New file.
* testsuite/ld-elf/orphan-10.s: New file.
* NEWS: Mention change in behaviour.
When picking an lma_region for an orphan section we currently create a
new lang_output_section_statement_type and then populate this with the
orphan section.
The problem is that the lang_output_section_statement_type has a prev
pointer that links back to the previous output section. For non-orphan
output sections, that are created in linker script order, the prev
pointer will point to the output section that appears previous in linker
script order, as you'd probably expect.
The problem is that orphan sections are placed after processing the
linker script, and so, in the case of an output section created for an
orphan input section, the prev pointer actually points to the last
output section created.
This causes some unexpected behaviour when the orphan section is not
placed after the last non-orphan section that was created.
For example, consider this linker script:
MEMORY {
TEXT : ORIGIN = 0x200, LENGTH = 0x10
RODATA : ORIGIN = 0x400, LENGTH = 0x10
}
SECTIONS {
.text : {*(.text) } AT>TEXT
.data : AT(0x300) { *(.data) }
.rodata : { *(.rodata) } AT>RODATA
}
If we are processing an orphan section '.data.1' and decide to place
this after '.data', then the output section created will have a prev
pointer that references the '.rodata' output section. The result of
this is that '.data.1' will actually be assigned to the RODATA lma
region, which is probably not the expected behaviour.
The reason why '.data.1' is placed into the lma region of the '.rodata'
section is that lma region propagation is done at the time we create the
output section, based on the previous output section pointer, which is
really just a last-output-section-created pointer at that point in time,
though the prev point is fixed up later to reflect the true order of the
output sections.
The solution I propose in this commit is to move the propagation of lma
regions into a separate pass of the linker, rather than performing this
as part of the enter/exit of output sections during linker script
parsing.
During this later phase we have all of the output sections to hand, and
the prev/next points have been fixed up by this point to reflect the
actual placement ordering.
There's a new test to cover this issue that passes on a range of
targets, however, some targets generate additional sections, or have
stricter memory region size requirements that make it harder to come
up with a generic pass pattern, that still tests the required
features. For now I've set the test to ignore these targets.
ld/ChangeLog:
* ldlang.c (lang_leave_output_section_statement): Move lma_region
logic to...
(lang_propagate_lma_regions): ...this new function.
(lang_process): Call new function.
* testsuite/ld-elf/orphan-9.d: New file.
* testsuite/ld-elf/orphan-9.ld: New file.
* testsuite/ld-elf/orphan-9.s: New file.
* NEWS: Mention change in behaviour.
lang_assignment_statement serves both assignments and asserts.
* ldlang.c (open_input_bfds): Check that lang_assignment_statement
is not an assert before referencing defsym.
Currently the EXCLUDE_FILE linker script construct can only be used
within the input section list, and applied only to the section pattern
immediately following the EXCLUDE_FILE. For example:
*.o (EXCLUDE_FILE (a.o) .text .rodata)
In this case all sections matching '.text' are included from all files
matching '*.o' but not from the file 'a.o'. All sections matching
'.rodata' are also included from all files matching '*.o' (incluing from
'a.o').
If the user wants to restrict the inclusion of section '.rodata' so that
this too is not taken from the file 'a.o' then the above example must be
extended like this:
*.o (EXCLUDE_FILE (a.o) .text EXCLUDE_FILE (a.o) .rodata)
However, due to the internal grammar of the linker script language the
snippet 'EXCLUDE_FILE (a.o) .text' is parsed by a pattern called
'wildcard_spec'. The same 'wildcard_spec' pattern is also used to parse
the input file name snippet '*.o' in the above examples. As a result of
this pattern reuse within the linker script grammar then the following
is also a valid linker script construct:
EXCLUDE_FILE (a.o) *.o (.text .rodata)
However, though the linker accepts this without complaint the
EXCLUDE_FILE part is silently ignored and has no effect.
This commit takes this last example and makes it a useful, valid,
construct. The last example now means to include sections '.text' and
'.rodata' from all files matching '*.o' except for the file 'a.o'.
If the list of input sections is long, and the user knows that the file
exclusion applies across the list then the second form might be a
clearer alternative to replicating the EXCLUDE_FILE construct.
I've added a set of tests for EXCLUDE_FILE to the linker, including
tests for the new functionality.
ld/ChangeLog:
* ldlang.h (struct lang_wild_statement_struct): Add
exclude_name_list field.
* ldlang.c (walk_wild_file_in_exclude_list): New function.
(walk_wild_consider_section): Use new
walk_wild_file_in_exclude_list function.
(walk_wild_file): Add call to walk_wild_file_in_exclude_list.
(print_wild_statement): Print new exclude_name_list field.
(lang_add_wild): Initialise new exclude_name_list field.
* testsuite/ld-scripts/exclude-file-1.d: New file.
* testsuite/ld-scripts/exclude-file-1.map: New file.
* testsuite/ld-scripts/exclude-file-1.t: New file.
* testsuite/ld-scripts/exclude-file-2.d: New file.
* testsuite/ld-scripts/exclude-file-2.map: New file.
* testsuite/ld-scripts/exclude-file-2.t: New file.
* testsuite/ld-scripts/exclude-file-3.d: New file.
* testsuite/ld-scripts/exclude-file-3.map: New file.
* testsuite/ld-scripts/exclude-file-3.t: New file.
* testsuite/ld-scripts/exclude-file-4.d: New file.
* testsuite/ld-scripts/exclude-file-4.map: New file.
* testsuite/ld-scripts/exclude-file-4.t: New file.
* testsuite/ld-scripts/exclude-file-a.s: New file.
* testsuite/ld-scripts/exclude-file-b.s: New file.
* testsuite/ld-scripts/exclude-file.exp: New file.
* ld.texinfo (Input Section Basics): Update description of
EXCLUDE_FILE to cover the new features.
* NEWS: Mention new EXCLUDE_FILE usage.
See https://sourceware.org/ml/binutils/2016-07/msg00091.html
This patch stop --gc-sections elf_gc_sweep_symbol localizing symbols
that ought to remain global.
The difficulty with always descending into output section statements
is that symbols defined by the script in such statements don't have
a bfd section when lang_do_assignments runs early in the link process.
There are two approaches to curing this problem. Either we can
create the bfd section early, or we can use a special section. This
patch takes the latter approach and uses bfd_und_section. (Creating
bfd sections early results in changed output section order, and thus
lots of testsuite failures. You can't create all output sections
early to ensure proper ordering as KEEP then stops empty sections
from being stripped.)
The wrinkle with this approach is that some code that runs at
gc-sections time needs to be made aware of the odd defined symbols
using bfd_und_section.
bfd/
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Handle symbols
defined temporarily with bfd_und_section.
* elflink.c (_bfd_elf_gc_keep): Don't set SEC_KEEP for bfd_und_section.
* elfxx-mips.c (mips_elf_local_pic_function_p): Exclude defined
symbols with bfd_und_section.
ld/
* ldlang.c (lang_do_assignments_1): Descend into output section
statements that do not yet have bfd sections. Set symbol section
temporarily for symbols defined in such statements to the undefined
section. Don't error on data or reloc statements until final phase.
* ldexp.c (exp_fold_tree_1 <etree_assign>): Handle bfd_und_section
in expld.section.
* testsuite/ld-mmix/bpo-10.d: Adjust.
* testsuite/ld-mmix/bpo-11.d: Adjust.
It was like printf, which means you can't use bfd_set_error_handler to
hook in a function to do something and then call the original handler.
The patch also deletes some unused functions and makes pointers local.
bfd/
* bfd-in.h: Include stdarg.h.
* bfd.c (bfd_error_handler_type): Make like vprintf.
(_bfd_error_internal): Rename from _bfd_error_handler. Make static.
(error_handler_internal): New function, split out from..
(_bfd_default_error_handler): ..here. Rename to _bfd_error_handler.
(bfd_set_error_handler): Update.
(bfd_get_error_handler, bfd_get_assert_handler): Delete.
(_bfd_assert_handler): Make static.
* coffgen.c (null_error_handler): Update params.
* elf-bfd.h (struct elf_backend_data <link_order_error_handler>):
Don't use bfd_error_handler_type.
* elf64-mmix.c (mmix_dump_bpo_gregs): Likewise.
* elfxx-target.h (elf_backend_link_order_error_handler): Default
to _bfd_error_handler.
* libbfd-in.h (_bfd_default_error_handler): Don't declare.
(bfd_assert_handler_type): Likewise.
(_bfd_error_handler): Update.
* bfd-in2.h: Regenerate.
* libbfd.h: Regenerate.
ld/
* ldlang.c (ignore_bfd_errors): Update params.
Not much to see here, just renaming a function.
bfd/
* targets.c (bfd_seach_for_target): Rename to..
(bfd_iterate_over_targets): ..this. Rewrite doc.
* bfd-in2.h: Regenerate.
ld/
* ldlang.c (open_output): Replace bfd_search_for_target with
bfd_iterate_over_targets. Localize vars.
Many more places use abfd->my_archive rather than bfd_my_archive (abfd),
so let's make the code consistently use the first idiom.
bfd/
* bfd-in.h (bfd_my_archive): Delete.
* bfd-in2.h: Regenerate.
binutils/
* ar.c: Expand uses of bfd_my_archive.
* size.c: Likewise.
ld/
* ldlang.c: Expand uses of bfd_my_archive.
* ldmain.c: Likewise.
* ldmisc.c: Likewise.
* plugin.c: Likewise.
Move ELF relocation check after lang_gc_sections so that all the
reference counting code for plt and got relocs can be removed. This
only affects ELF targets which check relocations after opening all
input file.
* ldlang.c (lang_check_relocs): New function.
(lang_process): Call lang_check_relocs after lang_gc_sections.
* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Don't
call _bfd_elf_link_check_relocs here.
H.J. Lu
Alan Modra
Maciej W. Rozycki
Andrew Burgess
Nick Clifton
Maciej W. Rozycki
Tristan Gingold
Igor Kudrin
Ambrogino Modigliani