The actual logic is to keep the output section if the output section
would have been ro/rw.
This is both simpler and more practical, as the intention is linker
scripts is to always keep of of a pair of ONLY_IF_RO/ONLY_IF_RW.
llvm-svn: 282099
This is PR30442.
Previously we were failed to parce complex expressions like:
foo : { *(SORT_BY_NAME(bar) zed) }
Main idea of patch that globs and excludes can be wrapped in a SORT.
There is a difference in semanics of ld/gold:
ld likes:
*(SORT(EXCLUDE_FILE (*file1.o) .foo.1))
gold likes:
*(EXCLUDE_FILE (*file1.o) SORT(.foo.1))
Patch implements ld grammar, complex expressions like
next is not a problem anymore:
.abc : { *(SORT(.foo.* EXCLUDE_FILE (*file1.o) .bar.*) .bar.*) }
Differential revision: https://reviews.llvm.org/D24758
llvm-svn: 282078
When final image has several .bss sections, lld fails
because second .bss always has zero VA. This causes
link error "Not enough space for ELF and program headers"
llvm-svn: 282067
It is not only a bit more straightforward now, but also next 2 issues are solved:
* It just crashed on ".foo : { *(EXCLUDE_FILE (*file1.o)) }" before.
* It accepted multiple EXCLUDE_FILEs in a row.
Differential revision: https://reviews.llvm.org/D24726
llvm-svn: 282060
This reverts commit r282021, bringing back r282015.
The problem was that the comparison function was not a strict weak
ordering anymore, which this patch fixes.
Original message:
Only restrict order if both sections are in the script.
This matches gold and bfd behavior and is required to handle some scripts.
The script has to assume where PT_LOADs start in order to align that
spot. If we don't allow section it doesn't know about to move to the
middle, we can need more PT_LOADs and those will not be aligned.
llvm-svn: 282035
This matches gold and bfd behavior and is required to handle some scripts.
The script has to assume where PT_LOADs start in order to align that
spot. If we don't allow section it doesn't know about to move to the
middle, we can need more PT_LOADs and those will not be aligned.
llvm-svn: 282015
This is particularly important when the symbol comes from a linker
script. It is common to use the same linker script for shared
libraries and executables. Without this we would always fail to link
shared libraries with -z,defs and a linker script with an ENTRY
directive.
llvm-svn: 281989
Linker scripts are responsible for aliging '.'. Since they are
designed for bfd which has no --rosegment, they don't align the RO to
RX transition.
llvm-svn: 281978
In most cases that means just not checking the address when we don't
need it.
For some tests it is easier to just set . to a known value.
llvm-svn: 281976
Previously it used llvm-readobj -s, now changed to llvm-objdump -section-headers,
that reduced the output significantly and helps to read/support it.
llvm-svn: 281832
Our implementation supported integer value previously.
ld can use expression,
for example, it is OK to write
. = SEGMENT_START("foobar", .);
Patch implements that.
llvm-svn: 281831
It was possible situation about some commands just were not processed
(were skipped) because of a bug appeared when constraint checking used.
Testcase is attached.
llvm-svn: 281818
This matches gold and bfd, and is pretty much required by some linker
scripts. They end with commands like
foo 0 : { *(bar) }
if we put any SHF_ALLOC sections after they can have an address that
is too low.
llvm-svn: 281778
This matches bfd behavior. It also makes future changes simpler as we
don't have to worry about ignoring these commands in multiple places
llvm-svn: 281775
With fix for 2 bots. Details about the fix performed is on a review page.
Initial commit message:
This is PR30387:
From PR description:
We fail to parse
SECTIONS
{
foo :
{
*(sec0 EXCLUDE_FILE (zed1.o) sec1 EXCLUDE_FILE (zed2.o) sec2 )
}
}
The semantics according to bfd are:
Include sec1 from every file but zed1.o
Include sec2 from every file but zed2.o
Include sec0 from every file
Patch implements the support.
Differential revision: https://reviews.llvm.org/D24650
llvm-svn: 281754
This fixes pr30367, but more importantly, it changes how we compute offsets.
Now offset computation in a walk over linker script commands, like the
rest of assignAddresses. IMHO this is simpler to understand and if we
ever have to create multiple outputsections or chunks to change how we
handle test/ELF/linkerscript/alternate-sections.s it should be easier
to do it.
llvm-svn: 281736
This is PR30387:
From PR description:
We fail to parse
SECTIONS
{
foo :
{
*(sec0 EXCLUDE_FILE (zed1.o) sec1 EXCLUDE_FILE (zed2.o) sec2 )
}
}
The semantics according to bfd are:
Include sec1 from every file but zed1.o
Include sec2 from every file but zed2.o
Include sec0 from every file
Patch implements the support.
Differential revision: https://reviews.llvm.org/D24650
llvm-svn: 281721
This is PR30386,
SORT_BY_INIT_PRIORITY is a keyword can be used to sort sections by numerical value of the
GCC init_priority attribute encoded in the section name.
Differential revision: https://reviews.llvm.org/D24611
llvm-svn: 281646
Previously we combined sections by name if linkerscript was used.
For that we had to disable SHF_MERGE handling temporarily, but then
found that implementing it properly will require additional complexity layers like
subsections or something.
At the same time looks we can live with multiple output sections approach for now.
That patch do this change.
Differential revision: https://reviews.llvm.org/D24127
llvm-svn: 280801
Patch implements FILL just as alias for =fillexpr.
This allows to make implementation much shorted and simpler than D24186.
Differential revision: https://reviews.llvm.org/D24227
llvm-svn: 280708
Windows does not allow opened files to be removed. This patch
fixes two types of errors.
- Output file being the same as input file. Because LLD itself
holds a file descriptor of the input file, it cannot create an
output file with the same name as a new file.
- Removing files before releasing MemoryBuffer objects.
These tests are not failing no because MemoryBuffer happens to
decide not to use mmap on these files. But we shouldn't rely on
that behavior.
llvm-svn: 280507
Both bfd and gold accept:
foo = 1K;
bar = 1M;
zed = 1H;
And lowercase forms: k, m, h.
Patch adds support for that.
Differential revision: https://reviews.llvm.org/D24194
llvm-svn: 280494
Symbol assignments outside of SECTIONS command need to be created
even when SECTIONS command is not used.
Differential Revision: https://reviews.llvm.org/D23751
llvm-svn: 280252
Allows adding start and/or end symbols to special output sections,
like .eh_frame_hdr, which aren't lists of regular input sections.
Differential revision: https://reviews.llvm.org/D23716
llvm-svn: 280205
FreeBSD/mips script has non-wildcard filename specifications:
.text :
{
start.o(.text*)
Patch adds support for that, this is PR29115.
Differential revision: https://reviews.llvm.org/D23839
llvm-svn: 280069
GNU gold handles output section fillers as 32-bit values.
This patch makes LLD compatible with that behavior.
Differential revision: https://reviews.llvm.org/D23181
llvm-svn: 280018
This is fix for PR28976.
Problem was that in scanRelocs, we computed relocation offset too early
for case when linkerscript was used. Patch fixes the issue
delaying the calculation.
Differential revision: https://reviews.llvm.org/D23655
llvm-svn: 279264
Previously DT_PREINIT_ARRAYSZ, DT_INIT_ARRAYSZ and DT_FINI_ARRAYSZ
were set to zero when lincerscript was used becase sections sizes are
calculated later that were taken.
Patch delays values calculation for these entries. Testcase is provided.
Differential revision: https://reviews.llvm.org/D23663
llvm-svn: 279258
You can force input section alignment within an output section by using SUBALIGN. The
value specified overrides any alignment given by input sections, whether larger or smaller.
SUBALIGN is used in many projects in the wild.
Differential revision: https://reviews.llvm.org/D23063
llvm-svn: 279256
We only support assignments inside SECTIONS, but this does not match
the behavior of GNU linker which also allows them outside SECTIONS.
The only restriction on assignments outside SECTIONS is that they
cannot reference . (they have to be absolute expressions).
Differential Revision: https://reviews.llvm.org/D23598
llvm-svn: 279033
The linker will normally set the LMA equal to the VMA.
You can change that by using the AT keyword.
The expression lma that follows the AT keyword specifies
the load address of the section.
Patch implements this keyword.
Differential revision: https://reviews.llvm.org/D19272
llvm-svn: 278911
This add support for HIDDEN command which can be used to define
a symbol that will be hidden and won't be exported.
Differential Revision: https://reviews.llvm.org/D23534
llvm-svn: 278770
Previously we searched output section by name to assign VA. That did not
work in the case when multiple output sections with different constraints were defined in script.
Testcase shows the possible issue scenario, patch fixes the issue.
Differential revision: https://reviews.llvm.org/D23451
llvm-svn: 278561
After latest changes we combine input sections with
different attributes into single output section.
Problem here is that regular output sections does not
support adding mergeable input sections (and vise versa).
Patch just temporarily disables merging for now at
the same way we do for -O0 for example.
This change helps for linking FreeBSD kernel.
Differential revision: https://reviews.llvm.org/D23447
llvm-svn: 278555
Previously filtering that was used worked incorrectly.
For example for next script it would just remove both sections completely:
SECTIONS {
. = 0x1000;
.aaa : ONLY_IF_RW { *(.aaa.*) }
. = 0x2000;
.aaa : ONLY_IF_RO { *(.aaa.*) }
}
Patch fixes above issues and adds testcase showing the issue. Testcase is a subset of
FreeBSD script which has:
.eh_frame : ONLY_IF_RO { KEEP (*(.eh_frame)) }
...
.eh_frame : ONLY_IF_RW { KEEP (*(.eh_frame)) }
Differential revision: https://reviews.llvm.org/D23326
llvm-svn: 278486
Previously, we created two or more output sections if there are
input sections with the same name but with different attributes.
That is a wrong behavior. This patch fixes the issue.
One thing we need to do is to merge output section attributes.
Currently, we create an output section based on the first input
section's attributes. This may make a wrong output section
attributes. What we need to do is to bitwise-OR attributes.
We'll do it in a follow-up patch.
llvm-svn: 278461
SIZEOF_HEADERS - Return the size in bytes of the output file’s headers.
It is is a feature used in FreeBsd script, for example.
There is a discussion on PR28688 page about it.
Differential revision: https://reviews.llvm.org/D23165
llvm-svn: 278204
I faced that when tried to link FreeBSD kernel.
It was "duplicate symbol: _edata in (internal) and (internal)" error.
_data was a shared symbol that came from hack.so. At first it was replaced with DefinedRegular by the code
disabled in this patch and later when script tried to define the same symbol - the error was shown.
In the same situation (as given in testcase) ld defines them as UND. gold defines as ABS with zero value.
Patch just disables any operations of creating these symbols if script do layout.
Differential revision: https://reviews.llvm.org/D23206
llvm-svn: 277986
ASSERT(exp, message)
Ensure that exp is non-zero. If it is zero, then exit the linker with an error
code, and print message.
ASSERT is useful and was seen in few projects in the wild.
Differential revision: https://reviews.llvm.org/D22912
llvm-svn: 277710
According to spec:
"SORT_BY_ALIGNMENT will sort sections into descending order by
alignment before placing them in the output file"
Previously they were sorted into ascending order.
llvm-svn: 277706
With the previous change, it is now obvious that readProvide in
this context appended new commands to a wrong command list.
It was mistakenly adding new commands to the top level.
Thus, all commands inside output section descriptions were
interpreted as they were written on top level.
PROVIDE command naturally requires symbol assignment support
in the output section description. We don't have that one yet.
I removed the implementation because there's no way to fix it now.
We can resurrect the test once we support the symbol assignment
(with a modification to detect errors that we failed to find as
described.)
llvm-svn: 277687
Previously, a decimal filler expression is interpreted as a byte value.
Gold on the other hand use it as a 32-bit big-endian value.
This patch fixes the compatibility issue.
Differential Revision: https://reviews.llvm.org/D23142
llvm-svn: 277680
Previously we supported only sorting by name.
When there are nested section sorting commands in linker script, there can be at most 1
level of nesting for section sorting commands.
SORT_BY_NAME (SORT_BY_ALIGNMENT (wildcard section pattern)). It will sort the input
sections by name first, then by alignment if 2 sections have the same name.
SORT_BY_ALIGNMENT (SORT_BY_NAME (wildcard section pattern)). It will sort the input
sections by alignment first, then by name if 2 sections have the same alignment.
SORT_BY_NAME (SORT_BY_NAME (wildcard section pattern)) is treated the same as SORT_
BY_NAME (wildcard section pattern).
SORT_BY_ALIGNMENT (SORT_BY_ALIGNMENT (wildcard section pattern)) is treated the
same as SORT_BY_ALIGNMENT (wildcard section pattern).
All other nested section sorting commands are invalid.
Patch implements that all above.
Differential revision: https://reviews.llvm.org/D23019
llvm-svn: 277583
This is a bit of an odd feature. It is normally used in
. = SEGMENT_START(seg, val);
In bfd it evaluates to val or to the value of the corresponding
-T<seg>-segment. Note that the -T<seg>-segment in bfd doesn't actually
change the segment address, just the value this evaluates too,
including in the default linker script.
In gold the -T<seg>-segment options do change the segment address and
seeing this expressions in linker scripts disables the options.
For new this just always evaluates the expression to val.
llvm-svn: 277014
Some scripts can contain SORT(CONSTRUCTORS) expression:
https://svnweb.freebsd.org/base/head/sys/conf/ldscript.amd64?revision=284870&view=markup#l152
for ELF it just a nop:
"When linking object file formats which do not support arbitrary sections, such as ECOFF and XCOFF, the linker will automatically recognize C++ global constructors and destructors by name. For these object file formats, the CONSTRUCTORS command tells the linker to place constructor information in the output section where the CONSTRUCTORS command appears. The CONSTRUCTORS command is ignored for other object file formats."
(http://www.sourceware.org/binutils/docs-2.10/ld_3.html)
So patch implements ignoring.
Differential revision: https://reviews.llvm.org/D22848
llvm-svn: 276965
In compare with what GNU linkers do (https://sourceware.org/binutils/docs/ld/Builtin-Functions.html),
this implementation simple:
Do not touch DATA_SEGMENT_ALIGN, it do what it do now - just aligns to the page boundary.
Parameters of DATA_SEGMENT_RELRO_END is ignored. That should be correct as it is usually just a 24 bytes
shift that allows to protect first 3 entries of got.plt with relro.
(https://svnweb.freebsd.org/base/head/sys/conf/ldscript.amd64?revision=284870&view=markup#l146).
DATA_SEGMENT_RELRO_END just aligns to the page boundary.
That is what expected because all sections that are not affected by relro should be on another memory page.
So at fact the difference with documented behavior is that we do not pad DATA_SEGMENT_ALIGN.
3 entries of got.plt are uncovered by relro, but functionality is simple and equal to lld behavior
for case when script is not given.
Differential revision: https://reviews.llvm.org/D22813
llvm-svn: 276778
We can simplify the evaluation of DATA_SEGMENT_ALIGN
just to simple align(). That way it will work exactly like we have in non-script case.
Change was suggested by Rafael Ávila de Espíndola
Differential revision: https://reviews.llvm.org/D22807
llvm-svn: 276745
PROVIDE request us to define a symbol only if it is referenced and is
not defined by any object included in the link. We created the
symbol in the symbol table no matter what.
Differential Revision: https://reviews.llvm.org/D22739
llvm-svn: 276592
Rafael Espindola