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
We would crash if a SHF_LINK_ORDER section pointed to a non
InputSection section. Since those sections are not merged in order,
SHF_LINK_ORDER is pretty meaningless and we can error on that case.
llvm-svn: 304327
This change converts the writing of the .ARM.exidx sentinel section to use
the InputSectionDescriptions instead of OutputSection::Sections this is in
preparation for the retirement of OutputSection::Sections.
Differential Revision: https://reviews.llvm.org/D33500
llvm-svn: 304289
This happens when attempting to link shared libraries using exceptions on
MIPS. It requires -z notext because clang generates R_MIPS_64 relocations
inside .eh_frame.
The crash happened because for EhInputSection the OutSec member is null.
Patch by Alexander Richardson!
llvm-svn: 304260
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
I found that during visual inspection of code while wrote different patch.
Script in testcase probably have nothing common with real life, but
we segfault currently using it.
If output section is known NOBITS, there is no need to create
writers threads for doing nothing or proccess any filler logic that
is useless here. We can just early return, that is what this patch do.
DIfferential revision: https://reviews.llvm.org/D33646
llvm-svn: 304192
InputSections may contain MergeInputSection members which trigger
a segmentation fault when trying to cast them to InputSection.
Differential Revision: https://reviews.llvm.org/D33628
llvm-svn: 304189
While the following expression is handled fine:
PROVIDE_HIDDEN(newsym = oldsym + address);
The following expression triggers an error because the expression
is evaluated as absolute:
PROVIDE_HIDDEN(newsym = ALIGN(oldsym, CONSTANT(MAXPAGESIZE)) + address);
To avoid this error, we use late evaluation for ALIGN by making the
alignment an attribute of the expression itself.
Differential Revision: https://reviews.llvm.org/D33629
llvm-svn: 304185
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
This is PR33052, "Bug 33052 - -r eats comdats ".
To fix it I stop removing group section from out when -r is given
and fixing SHT_GROUP content when writing it just like we do some
other fixup, e.g. for Rel[a]. (it needs fix for section indices that
are in group).
Differential revision: https://reviews.llvm.org/D33485
llvm-svn: 304140
The .dynamic section of an ELF almost doesn't need to be written to with
the exception of the DT_DEBUG entry. For several reasons having a read
only .dynamic section would be useful. This change adds the -z keyword
"rodynamic" which forces .dynamic to be read-only. In this case DT_DEBUG
will not be emited.
Patch by Jake Ehrlich
Differential Revision: https://reviews.llvm.org/D33251
llvm-svn: 304024
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
I found this when builded llc binary using gcc 5.4.1 + LLD.
gcc produces duplicate entries in .debug_gnu_pubtypes section, ex:
UnifyFunctionExitNodes.cpp.o has:
0x0000ac07 EXTERNAL TYPE "std::success_type<void*>"
0x0000ac07 EXTERNAL TYPE "std::success_type<void*>"
clang produces single entry here:
0x0000d291 EXTERNAL TYPE "std::__success_type<void *>"
If we link output from gcc with LLD, that would produce excessive duplicate
entries in .gdb_index constant pool area. That does not seem affect gdb work,
but makes .gdb_index larger than it can be.
I also checked that gold filters out such duplicates too. Patch fixes it.
Differential revision: https://reviews.llvm.org/D32647
llvm-svn: 303975
https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html says:
"A CU vector in the constant pool is a sequence of offset_type values.
The first value is the number of CU indices in the vector.
Each subsequent value is the index and symbol attributes of a CU in the CU list."
Previously we keeped 2 values until the end, what was useless.
Initially was a part of D32647, though it is possible to split out.
Patch do that.
Differential revision: https://reviews.llvm.org/D33551
llvm-svn: 303973
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
Originally this was intended to be set up so that when linking
a PDB which refers to a type server, it would only visit the
PDB once, and on subsequent visitations it would just skip it
since all the records had already been added.
Due to some C++ scoping issues, this was not occurring and it
was revisiting the type server every time, which caused every
record to end up being thrown away on all subsequent visitations.
This doesn't affect the performance of linking clang-cl generated
object files because we don't use type servers, but when linking
object files and libraries generated with /Zi via MSVC, this means
only 1 object file has to be linked instead of N object files, so
the speedup is quite large.
llvm-svn: 303920
If you pass /delayload:<dllname> to the COFF linker, it creates thunks
so that DLLs are loaded when they are used for the first time instead of
load-time.
This mechanism do not work for data symbols as there's no way to trap
acccesses to data imported from DLLs. (Technically, I think if we do not
initially map dllimport tables in memory, we could actually trap accesses
and delay-load data symbols, but that's not what Windows do.)
This patch is to report an error when you try to delay-load data symbols.
Fixes https://bugs.llvm.org/show_bug.cgi?id=33106
Differential Revision: https://reviews.llvm.org/D33557
llvm-svn: 303890
This is a different implementation than r303225 (which was reverted
in r303270, re-submitted in r303304 and then re-reverted in r303527).
In the previous patch, I tried to add Live bit to each dllimported
symbol. It turned out that it didn't work with "oldnames.lib" which
contains a lot of weak aliases to dllimported symbols.
The way we handle weak aliases is to check if undefined symbols
can be resolved using weak aliases, and if so, memcpy the Defined
symbols to weak Undefined symbols, so that any references to weak
aliases automatically see defined symbols instead of undefined ones.
This memcpy happens before MarkLive kicks in.
That means we may have multiple copies of dllimported symbols. So
turning on one instance's Live bit is not enough.
This patch moves the Live bit to dllimport file. Since multiple
copies of dllsymbols still point to the same file, we can use it as the
central repository to keep track of liveness.
Differential Revision: https://reviews.llvm.org/D33520
llvm-svn: 303814
It is not clear why a synthetic section wants to use padding defined
in the linker script. The padding is for the space between sections.
It was also missing a test.
llvm-svn: 303812
This is the only place we use threads for ICF. The intention of this code
was to split an input vector into 256 shards and process them in parallel.
What the code was actually doing was to split an input into 257 shards,
process the first 256 shards in parallel, and the remaining one in serial.
That means this code takes ceil(256/n)+1 instead of ceil(256/n) where n
is the number of available CPU cores. The former converges to 2 while
the latter converges to 1.
This patches fixes the above issue.
llvm-svn: 303797
Summary:
This is required on some platforms, as GNU libstdc++ std::call_once is known to be buggy.
This fixes operation of LLD on at least NetBSD and perhaps OpenBSD and Linux PowerPC.
The same change has been introduced to LLVM and LLDB.
Reviewers: ruiu
Reviewed By: ruiu
Subscribers: emaste, #lld
Tags: #lld
Differential Revision: https://reviews.llvm.org/D33508
llvm-svn: 303788
A variable `ComdatGroup` is not supposed to contain a large number of
items. Even when linking clang, it ends up having only 300K strings.
It doesn't make sense to use CachedHashStringRef for this hash table.
This patch has neutral or slightly positive impact on performance while
reducing code complexity.
llvm-svn: 303787
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
Rafael Espindola