This is PR36515.
Currenly if we have a script like .debug_info 0 : { *(.debug_info) },
we would not remove this section and keep it in the output.
That does not work, because it is common case for
debug sections to have a zero address expression.
Patch changes behavior so that we remove only sections
that do not use symbols in its expressions.
Differential revision: https://reviews.llvm.org/D43863
llvm-svn: 326430
This fixes pr36475.
I think this code can be simplified a bit, but I would like to check
in the more direct fix if we are in agreement on the direction and
then refactor.
This is not something that bfd does. The issue is not noticed in bfd
because it keeps fewer sections from the linkerscript in the output.
The reasons why it seems reasonable to do this:
- As George noticed, we would still keep the flags if the output
section had both an empty synthetic section and a regular section
- We need an heuristic to find the flags of output sections. Using the
flags of a synthetic section that would have been there seems a
reasonable heuristic.
llvm-svn: 326137
We sometimes need to iterate over input sections for a given
output section. It is not very convinent because we have to iterate
over section descriptions.
Patch introduces getInputSections helper, it simplifies things.
Differential revision: https://reviews.llvm.org/D43574
llvm-svn: 325763
The profailing style in lld seem to be to not include such empty lines.
Clang-tidy/clang-format seem to handle this just fine.
Differential Revision: https://reviews.llvm.org/D43528
llvm-svn: 325629
If two sections are in the same PT_LOAD, their relatives offsets,
virtual address and physical addresses are all the same.
I initially wanted to have a single global LMAOffset, on the
assumption that every ELF file was in practiced loaded contiguously in
both physical and virtual memory.
Unfortunately that is not the case. The linux kernel has:
LOAD 0x200000 0xffffffff81000000 0x0000000001000000 0xced000 0xced000 R E 0x200000
LOAD 0x1000000 0xffffffff81e00000 0x0000000001e00000 0x15f000 0x15f000 RW 0x200000
LOAD 0x1200000 0x0000000000000000 0x0000000001f5f000 0x01b198 0x01b198 RW 0x200000
LOAD 0x137b000 0xffffffff81f7b000 0x0000000001f7b000 0x116000 0x1ec000 RWE 0x200000
The delta for all but the third PT_LOAD is the same:
0xffffffff80000000. I think the 3rd one is a hack for implementing per
cpu data, but we can't break that.
llvm-svn: 323456
AT> lma_region expression allows to specify the memory region
for section load address.
Should fix PR35684.
Differential revision: https://reviews.llvm.org/D41397
llvm-svn: 322359
The size of an OutputSection is calculated early, to aid handling of compressed
debug sections. However, subsequent to this point, unused synthetic sections are
removed. In the event that an OutputSection, from which such an InputSection is
removed, is still required (e.g. because it has a symbol assignment), and no longer
has any InputSections, dot assignments, or BYTE()-family directives, the size
member is never updated when processing the commands. If the removed InputSection
had a non-zero size (such as a .got.plt section), the section ends up with the
wrong size in the output.
The fix is to reset the OutputSection size prior to processing the linker script
commands relating to that OutputSection. This ensures that the size is correct even
in the above situation.
Additionally, to reduce the risk of developers misusing OutputSection Size and
InputSection OutSecOff, they are set to simply the number of InputSections in an
OutputSection, and the corresponding index respectively. We cannot completely
stop using them, due to SHF_LINK_ORDER sections requiring them.
Compressed debug sections also require the full size. This is now calculated in
maybeCompress for these kinds of sections.
Reviewers: ruiu, rafael
Differential Revision: https://reviews.llvm.org/D38361
llvm-svn: 320472
Now that DefinedRegular is the only remaining derived class of
Defined, we can merge the two classes.
Differential Revision: https://reviews.llvm.org/D39667
llvm-svn: 317448
Stop using SectionKey for creating output sections.
Initially SectionKey was designed because we merged section with
use of Flags and Alignment fields. Currently LLD merges them by name only,
except the case when -relocatable output is produced. In that case
we still merge sections only with the same flags and alignment.
There is probably no issue at all to stop using Flags and Alignment for -r and
just disable the merging in that case.
After doing that change we can get rid of using SectionKey. That is not only
simplifies the code, but also gives some perfomance boost.
I tried to link chrome and mozilla, results are next:
* chrome link time goes from 1,666750355s to 1,551585364s, that is about 7%.
* mozilla time changes from 3,210261947 to 3,153782940, or about 2%.
Differential revision: https://reviews.llvm.org/D39594
llvm-svn: 317406
Now that we have only SymbolBody as the symbol class. So, "SymbolBody"
is a bit strange name now. This is a mechanical change generated by
perl -i -pe s/SymbolBody/Symbol/g $(git grep -l SymbolBody lld/ELF lld/COFF)
nd clang-format-diff.
Differential Revision: https://reviews.llvm.org/D39459
llvm-svn: 317370
This moves reporting of garbage collected sections right after
we do GC. That simplifies things.
Differential revision: https://reviews.llvm.org/D39058
llvm-svn: 316759
"Commands" was ambiguous because in the linker script, everything is
a command. We used to handle only SECTIONS commands, and at the time,
it might make sense to call them the commands, but it is no longer
the case. We handle not only SECTIONS but also MEMORY, PHDRS, VERSION,
etc., and they are all commands.
llvm-svn: 315409
Previously, when we added an input section to an output section, we
called `OutputSectionFactory::addInputSec`. This isn't a good design
because, a factory class is intended to create a new object and
return it, but in this use case, it will never create a new object.
This patch fixes the design flaw.
llvm-svn: 315138
Factory::addInputSec added an output section to Script->Opt.Commands,
but that is too subtle. This patch makes it explicit so that it is easy
to see when a new element is added to Script->Opt.Commands.
llvm-svn: 315129
addSection function was hard to read because it behaves differently
depending on its arguments but what exactly it does is not clear.
Now it should be better. Still, it is not clear (not what but) why
it does what it does, but I'll take a look at it later.
llvm-svn: 315124
New lld's files are spread under lib subdirectory, and it isn't easy
to find which files are actually maintained. This patch moves maintained
files to Common subdirectory.
Differential Revision: https://reviews.llvm.org/D37645
llvm-svn: 314719
Patch removes one of OutputSectionFactory::addInputSec methods.
That allows to simplify reporting of discarded sections and
should help to D37561.
Differential revision: https://reviews.llvm.org/D37735
llvm-svn: 313361
It is a bit more convinent and helps to simplify logic
of program headers allocation a little.
Differential revision: https://reviews.llvm.org/D34956
llvm-svn: 312711
This is PR33889,
Patch adds support of combination of linkerscript and
-symbol-ordering-file option.
If no sorting commands are present in script inside section declaration
and no --sort-section option specified, code uses sorting from ordering
file if any exist.
Differential revision: https://reviews.llvm.org/D35843
llvm-svn: 310045
This is a bit of a hack, but it is *so* convenient.
Now that we create synthetic linker scripts when none is provided, we
always have to handle paired OutputSection and OutputsectionCommand and
keep a mapping from one to the other.
This patch simplifies things by merging them and creating what used to
be OutputSectionCommands really early.
llvm-svn: 309311
Previously we would merge relocation sections by name.
That did not work in some cases, like testcase shows.
Patch implements logic to merge relocation sections if their target
sections were merged into the same output section.
Differential revision: https://reviews.llvm.org/D33824
llvm-svn: 304886
This reduces how many times we have to map from OutputSection to
OutputSectionCommand. It is a required step to moving
clearOutputSections earlier.
In order to always use writeTo in OutputSectionCommand we have to call
fabricateDefaultCommands for -r links and move section compression
after it.
llvm-svn: 303784
We used to place orphans by just using compareSectionsNonScript.
Then we noticed that since linker scripts can use another order, we
should first try match the section to a given PT_LOAD. But there is
nothing special about PT_LOAD. The same issue can show up for
PT_GNU_RELRO for example.
In general, we have to search for the most similar section and put the
orphan next to it. Most similar being defined as how long they follow
the same code path in compareSecitonsNonScript.
That is what this patch does. We now compute a rank for each output
section, with a bit for each branch in what was
compareSectionsNonScript.
With this findOrphanPos is now fully general and orphan placement can
be optimized by placing every section with the same rank at once.
The included testcase is a variation of many-sections.s that uses
allocatable sections to avoid the fast path in the existing
code. Without threads it goes form 46 seconds to 0.9 seconds.
llvm-svn: 302903
We were already pretty close, the one exception was when a name was
reused in another SECTIONS directive:
SECTIONS {
.text : { *(.text) }
.data : { *(.data) }
}
SECTIONS {
.data : { *(other) }
}
In this case we would create a single .data and magically output
"other" while looking at the first OutputSectionCommand.
We now create two .data sections. This matches what gold does. If we
really want to create a single one, we should change the parser so that
the above is parsed as if the user had written
SECTIONS {
.text : { *(.text) }
.data : { *(.data) *(other)}
}
That is, there should be only one OutputSectionCommand for .data and
it would have two InputSectionDescriptions.
By itself this patch makes the code a bit more complicated, but is an
important step in allowing assignAddresses to operate just on the
linker script.
llvm-svn: 301484
Patch implements --compress-debug-sections=zlib.
In compare with D20211 (a year old patch, abandoned), it implementation
uses streaming and fully reimplemented, does not support zlib-gnu for
simplification.
This is PR32308.
Differential revision: https://reviews.llvm.org/D31941
llvm-svn: 300444
Rui Ueyama