Before InputSectionBase had an OutputSection pointer, but that was not
always valid. For example, if it was a merge section one actually had
to look at MergeSec->OutSec.
This was brittle and caused bugs like the one fixed by r304260.
We now have a single Parent pointer that points to an OutputSection
for InputSection, but to a SyntheticSection for merge sections and
.eh_frame. This makes it impossible to accidentally access an invalid
OutSec.
llvm-svn: 304338
When there is a linker script with .ARM.exidx in the SECTIONS
command we must add the .ARM.exidx sentinel section to the
InputSectionDescriptions as well as to OutputSection::Sections.
Differential Revision: https://reviews.llvm.org/D33496
llvm-svn: 304206
Now that we are trying to use the linker script representation as the
canonycal one, there are a few loops looking for just OutputSectionCommands.
Create a vector with just the OutputSectionCommands once that is
stable to simplify the rest of the code.
llvm-svn: 304181
On SPARC, .plt is both writeable and executable. The current way
sections are sorted means that lld puts it after .data/.bss. but it
really needs to be close to .test to make sure branches into .plt
don't overflow. I'd argue that because .bss is supposed to come last
on all architectures, we should change the default sort order such
that writable and executable sections come before sections that are
just writeable. read-only executable sections should still come after
sections that are just read-only of course. This diff makes this
change.
llvm-svn: 304008
In this way, the content and the flag is always consistent, which I
think better than removing the bit when input sections reaches the Writer.
llvm-svn: 303926
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
Once the dummy linker script is created, we want it to be used for
everything to avoid having two redundant representations that can get
out of sync.
We were already clearing OutputSections. With this patch we clear the
Sections vector of every OutputSection.
llvm-svn: 303703
This converts the last (chronologically) user of OutputSections to use
the linker script commands instead.
The idea is to convert all uses after fabricateDefaultCommands, so
that we have a single representation.
llvm-svn: 303384
GetSection is a template because write calls relocate.
relocate has two parts. The non alloc code really has to be a
template, as it is looking a raw input file data.
The alloc part is only a template because of getSize.
This patch folds the value of getSize early, detemplates
getRelocTargetVA and splits relocate into a templated non alloc case
and a regular function for the alloc case. This has the nice advantage
of making sure we collect all the information we need for relocations
before getting to InputSection::relocateNonAlloc.
Since we know got is alloc, it can just call the function directly and
avoid the template.
llvm-svn: 303355
Nothing special here, just detemplates code that became possible
to detemplate after recent commits in a straghtforward way.
Differential revision: https://reviews.llvm.org/D33234
llvm-svn: 303237
SymbolTableBaseSection was introduced.
Detemplation of SymbolTableSection should allow to detemplate more things.
Differential revision: https://reviews.llvm.org/D33124
llvm-svn: 303150
Switch to llvm::to_integer() everywhere in LLD instead of
StringRef::getAsInteger() because API of latter is confusing.
It returns true on error and false otherwise what makes reading
the code incomfortable.
Differential revision: https://reviews.llvm.org/D33187
llvm-svn: 303149
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
This behavior differs from the semantics implemented by GNU linkers
which only define this symbol iff ELF headers are in the memory
mapped segment.
Differential Revision: https://reviews.llvm.org/D33019
llvm-svn: 302687
This is a bit easier to read and a lot faster in some cases. A version
of many-sections.s with linker scripts goes from 0m41.232s to
0m19.575s.
llvm-svn: 302528
The code following this one already considers every possible insertion
point for orphan sections, there is no point in sorting them before.
llvm-svn: 302441
We can set SectionIndex tentatively as we process the linker script
instead of looking it repeatedly.
In general we should try to have as few name lookups as possible.
llvm-svn: 302299
In the non linker script case we would try very early to find out if
we could allocate the headers. Failing to do that would add extra
alignment to the first ro section, since we would set PageAlign
thinking it was the first section in the PT_LOAD.
In the linker script case the header allocation must be done in the
end, causing some duplication.
We now tentatively add the headers to the first PT_LOAD and if it
turns out they don't fit, remove them. With this we only need to
allocate the headers in one place in the code.
llvm-svn: 302186
The --section-start <name>=<address> needs to be translated into equivalent
linker script commands. There are a couple of problems with the existing
implementation:
- The --section-start with the lowest address is assumed to be at the start
of the map. This assumption is incorrect, we have to iterate through the
SectionStartMap to find the lowest address.
- The addresses in --section-start were being over-aligned when the
sections were marked as PageAlign. This is inconsistent with the use of
SectionStartMap in fixHeaders(), and can cause problems when the PageAlign
causes an "unable to move location counter backward" error when the
--section-start with PageAlign is aligned to an address higher than the next
--section-start. The ld.bfd and ld.gold seem to be more consistent with this
approach but this is not a well specified area.
This change fixes the problems above and also corrects a typo in which
fabricateDefaultCommands() is called with the wrong parameter, it should be
called with AllocateHeader not Config->MaxPageSize.
Differential Revision: https://reviews.llvm.org/D32749
llvm-svn: 302007
This version uses a set to speed up the synchronize method.
Original message:
Remove LinkerScript::flush.
This patch replaces flush with a last ditch attempt at synchronizing
the section list with the linker script "AST".
The synchronization is a bit of a hack and should in time be avoided
by creating the AST earlier so that modifications can be made directly
to it instead of modifying the section list and synchronizing it back.
This is the main step for fixing
https://bugs.llvm.org/show_bug.cgi?id=32816. With this in place I
think the only missing thing would be to have processCommands assign
section indexes as dummy offsets so that the sort in
OutputSection::finalize works.
With this LinkerScript::assignAddresses becomes much simpler, which
should help with the thunk work.
llvm-svn: 301745
This reverts commit r301678 since that change significantly slowed
down the linker. Before this patch, LLD could link clang in 8 seconds,
but with this patch it took 40 seconds.
llvm-svn: 301709
This patch replaces flush with a last ditch attempt at synchronizing
the section list with the linker script "AST".
The synchronization is a bit of a hack and should in time be avoided
by creating the AST earlier so that modifications can be made directly
to it instead of modifying the section list and synchronizing it back.
This is the main step for fixing
https://bugs.llvm.org/show_bug.cgi?id=32816. With this in place I
think the only missing thing would be to have processCommands assign
section indexes as dummy offsets so that the sort in
OutputSection::finalize works.
With this LinkerScript::assignAddresses becomes much simpler, which
should help with the thunk work.
llvm-svn: 301678
addIgnored defines a given symbol even if there is no existing
symbol with the same name. So, even if libc provides __tls_get_addr,
we should still be able to call addIgnored.
Differential Revision: https://reviews.llvm.org/D32053
llvm-svn: 301290
This change fabricates linker script commands for the case where there is
no linker script SECTIONS to control address assignment. This permits us
to have a single Script->assignAddresses() function.
There is a small change in user-visible-behavior with respect to the
handling of .tbss SHT_NOBITS, SHF_TLS as the Script->assignAddresses()
requires setDot() to be called with monotically increasing addresses.
The tls-offset.s test has been updated so that the script and non-script
results match.
This change should make the non-script behavior of lld closer to an
equivalent linker script.
Differential Revision: https://reviews.llvm.org/D31888
llvm-svn: 300687
