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.
NOCROSSREFS_TO is similar to the existing NOCROSSREFS command but only
checks one direction of cross referencing.
ld/ChangeLog
* ld.texinfo: Document NOCROSSREFS_TO script command.
* ldlang.h (struct lang_nocrossrefs): Add onlyfirst field.
(lang_add_nocrossref_to): New prototype.
* ldcref.c (check_local_sym_xref): Use onlyfirst to only look for
symbols defined in the first section.
(check_nocrossref): Likewise.
* ldgram.y (NOCROSSREFS_TO): New script command.
* ldlang.c (lang_add_nocrossref): Set onlyfirst to FALSE.
(lang_add_nocrossref_to): New function.
* ldlex.l (NOCROSSREFS_TO): New token.
* NEWS: Mention NOCROSSREFS_TO.
* testsuite/ld-scripts/cross4.t: New file.
* testsuite/ld-scripts/cross5.t: Likewise.
* testsuite/ld-scripts/cross6.t: Likewise.
* testsuite/ld-scripts/cross7.t: Likewise.
* testsuite/ld-scripts/crossref.exp: Run 4 new NOCROSSREFS_TO
tests.
* ldlang.c (print_output_section_statement): Show minfo size
in target machine address units.
(print_reloc_statement): Likewise.
(print_padding_statement): Likewise.
(print_data_statement): Likewise. Ensure minimum print_dot
increment of one address unit.
and one extraneous occurrence.
* ldlang.c (TO_ADDR, TO_SIZE, opb_shift): Move earlier in file.
(lang_insert_orphan): Use TO_ADDR in __stop sym calculation.
(print_input_section): Don't use TO_ADDR when printing section
size.
(lang_size_sections_1): Use TO_ADDR in overlay lma calculation.
(lang_size_sections): Use TO_ADDR in relro end calculation.
PR 18452
* ldlang.c (maybe_overlays): New static var.
(lang_size_sections_1): Set it here.
(struct check_sec): New.
(sort_sections_by_lma): Adjust for array of structs.
(sort_sections_by_vma): New function.
(lang_check_section_addresses): Check both LMA and VMA for overlap.
* testsuite/ld-scripts/rgn-over7.d: Adjust.
Some places tested SEC_LOAD, others SEC_HAS_CONTENTS.
* ldlang.c (IS_TBSS): New macro, extracted from..
(IGNORE_SECTION): ..here.
(lang_size_sections_1): Use IS_TBSS and IGNORE_SECTION.
(lang_size_sections, lang_do_assignments_1): Use IS_TBSS.
PR ld/19803
* ldlang.c (lang_add_gc_name): New function. Adds the provided
symbol name to the list of gc symbols.
(lang_process): Call lang_add_gc_name with entry_symbol_default if
entry_symbol.name is NULL. Use lang_add_gc_name to add the init
and fini function names.
* pe-dll.c (process_def_file_and_drectve): Add exported names to
the gc symbol list.
* testsuite/ld-pe/pr19803.s: Do not export _testval symbol.
* testsuite/ld-pe/pr19803.d: Tweak expected output.
Another option might be to not bump "dot" for .tbss alignment in the
main section sizing loop, but that could leak some of the following
section into the TLS segment. Leakage shouldn't matter since it will
be to bytes past the end of .tdata, but for now this is a safer
option.
PR ld/19264
* ldlang.c (lang_size_sections): Don't ignore .tbss when
adjusting start of relro region.
The last patch missed handling the case where the ideal place to put
an orphan was after a non-existent output section statement, as can
happen when not using the builtin linker scripts. This patch uses the
updated flags for that case too, and extends the support to mmo and pe.
PR ld/19162
* emultempl/elf32.em (gld${EMULATION_NAME}_place_orphan): Pass
updated flags to lang_output_section_find_by_flags.
* emultempl/mmo.em (mmo_place_orphan): Merge flags for any
other input sections that might match a new output section to
decide placement.
* emultempl/pe.em (gld_${EMULATION_NAME}_place_orphan): Likewise.
* emultempl/pep.em (gld_${EMULATION_NAME}_place_orphan): Likewise.
* ldlang.c (lang_output_section_find_by_flags): Add sec_flags param.
* ldlang.h (lang_output_section_find_by_flags): Update prototype.
Makes these symbols defined before bfd_elf_size_dynamic_sections, to
avoid horrible hacks elsewhere. The exp_fold_tree undefweak change
is necessary to define undefweak symbols early too. The comment was
wrong. PROVIDE in fact defines undefweak symbols, via
bfd_elf_record_link_assignment.
PR ld/19175
* ldlang.c (lang_insert_orphan): Evaluate __start_* and __stop_*
symbol PROVIDE expressions.
* ldexp.c (exp_fold_tree_1 <etree_provide>): Define undefweak
references.
Giving linker script symbols defined outside of output sections a
section-relative value early, leads to them being used in expressions
as if they were defined inside an output section. This can mean loss
of the section VMA, and wrong results.
ld/
PR ld/18963
* ldexp.h (struct ldexp_control): Add rel_from_abs.
(ldexp_finalize_syms): Declare.
* ldexp.c (new_rel_from_abs): Keep absolute for expressions
outside of output section statements. Set rel_from_abs.
(make_abs, exp_fold_tree, exp_fold_tree_no_dot): Clear rel_from_abs.
(struct definedness_hash_entry): Add final_sec, and comment.
(update_definedness): Set final_sec.
(set_sym_sections, ldexp_finalize_syms): New functions.
* ldlang.c (lang_process): Call ldexp_finalize_syms.
ld/testsuite
PR ld/18963
* ld-scripts/pr18963.d,
* ld-scripts/pr18963.t: New test.
* ld-scripts/expr.exp: Run it.
* ld-elf/provide-hidden-2.ld: Explicitly make "dot" absolute.
* ld-mips-elf/gp-hidden.sd: Don't care about _gp section.
* ld-mips-elf/no-shared-1-n32.d: Don't care about symbol shown at
start of .data section.
* ld-mips-elf/no-shared-1-n64.d: Likewise.
* ld-mips-elf/no-shared-1-o32.d: Likewise.
Replace the options --warn-orphan and --no-warn-orphan with a single
option --orphan-handling=MODE, where mode can be place, warn, error, and
discard.
Mode 'place' is the default, and is the current behaviour, placing the
orphan section into a suitable output section.
Mode 'warn' is the same as '--warn-orphan'. The orphan is also placed
using the same algorithm as for 'place'.
Mode 'error' is the same as '--warn-orphan' and '--fatal-warnings'.
Mode 'discard' assigns all output sections to the /DISCARD/ section.
ld/ChangeLog:
* ld.h (enum orphan_handling_enum): New.
(ld_config_type): Remove warn_orphan, add orphan_handling.
* ldemul.c (ldemul_place_orphan): Remove warning about orphan
sections.
* ldlang.c (ldlang_place_orphan): New function.
(lang_place_orphans): Call ldlang_place_orphan.
* ldlex.h (enum option_values): Remove OPTION_WARN_ORPHAN and
OPTION_NO_WARN_ORPHAN, add OPTION_ORPHAN_HANDLING.
* lexsup.c (ld_options): Remove 'warn-orphan' and
'no-warn-orphan', add 'orphan-handling'.
(parse_args): Remove handling for OPTION_WARN_ORPHAN and
OPTION_NO_WARN_ORPHAN, add handling for OPTION_ORPHAN_HANDLING.
* NEWS: Replace text about --warn-orphan with --orphan-handling.
* ld.texinfo (Options): Remove --warn-orphan entry and add
entry on --orphan-handling.
(Orphan Sections): Add reference to relevant command line options.
ld/testsuite/ChangeLog:
* ld-elf/elf.exp: Switch to rely on run_dump_test.
* ld-elf/orphan-5.l: Update expected output.
* ld-elf/orphan-5.d: New file.
* ld-elf/orphan-6.d: New file.
* ld-elf/orphan-6.l: New file.
* ld-elf/orphan-7.d: New file.
* ld-elf/orphan-7.map: New file.
* ld-elf/orphan-8.d: New file.
* ld-elf/orphan-8.map: New file.
Add a new command line option '--require-defined' to the linker. This
option operates identically to the '--undefined' option, except that if
the symbol is not defined in the final output file then the linker will
exit with an error.
When making use of --gc-section, or just when trying to pull in parts of
a library, it is not uncommon for a user to use the '--undefined'
command line option to specify a symbol that the user then expects to be
defined by one of the object files supplied to the link.
However, if for any reason the symbol is not satisfied by an object
provided to the link the user will be left with an undefined symbol in
the output file, instead of a defined symbol.
In some cases the above behaviour is what the user wants, in other cases
though we can do better. The '--require-defined' option tries to fill
this gap. The symbol passed to the '--require-defined' option is
treated exactly as if the symbol was passed to '--undefined', however,
before the linker exits a check is made that all symbols passed to
'--require-defined' are actually defined, if any are not then the link
will fail with an error.
ld/ChangeLog:
* ld.texinfo (Options): Document --require-defined option.
* ldlang.c (struct require_defined_symbol): New structure.
(require_defined_symbol_list): New variable.
(ldlang_add_require_defined): New function.
(ldlang_check_require_defined_symbols): New function.
(lang_process): Check required symbols are defined.
* ldlang.h (ldlang_add_require_defined): Declare.
* ldlex.h (enum option_values): Add OPTION_REQUIRE_DEFINED_SYMBOL.
* lexsup.c (ld_options): Add '--require-defined' entry.
(parse_args): Handle '--require-defined' entry.
* NEWS: Mention new '--require-defined' option.
ld/testsuite/ChangeLog:
* ld-undefined/require-defined-1.d: New file.
* ld-undefined/require-defined-2.d: New file.
* ld-undefined/require-defined-3.d: New file.
* ld-undefined/require-defined-4.d: New file.
* ld-undefined/require-defined-5.d: New file.
* ld-undefined/require-defined.exp: New file.
* ld-undefined/require-defined.s: New file.
