Some MIPS relocations depend on "gp" value. By default, this value has
0x7ff0 offset from a .got section. But relocatable files produced by a
compiler or a linker might redefine this default value and we have to
use it for a calculation of the relocation result. When we generate EXE
or DSO it's trivial. Generating a relocatable output is more difficult
case because the linker does calculate relocations in this case and
cannot store individual "gp" values used by each input object file.
As a workaround we add the "gp" value to the relocation addend.
This fixes https://llvm.org/pr31149
Differential revision: https://reviews.llvm.org/D45972
llvm-svn: 331772
On PowerPC calls to functions through the plt must be done through a call stub
that is responsible for:
1) Saving the toc pointer to the stack.
2) Loading the target functions address from the plt into both r12 and the
count register.
3) Indirectly branching to the target function.
Previously we have been emitting these call stubs to the .plt section, however
the .plt section should be reserved for the lazy symbol resolution stubs. This
patch moves the call stubs to the text section by moving the implementation from
writePlt to the thunk framework.
Differential Revision: https://reviews.llvm.org/D46204
llvm-svn: 331607
The current support for V1 ABI in LLD is incomplete.
This patch removes V1 ABI support and changes the default behavior to V2 ABI,
issuing an error when using the V1 ABI. It also updates the testcases to V2
and removes any V1 specific tests.
Differential Revision: https://reviews.llvm.org/D46316
llvm-svn: 331529
Now that getSectionPiece is fast (uses a hash) it is probably OK to
split merge sections early.
The reason I want to do this is to split eh_frame sections in the same
place.
This does mean that we have to decompress early. Given that the only
compressed sections are debug info, I don't think we are missing much.
It is a small improvement: 0.5% on the geometric mean.
llvm-svn: 331058
PPC64 V2 ABI describes two entry points to a function. The global entry point
sets up the TOC base pointer. When calling a local function, the call should
branch to the local entry point rather than the global entry point.
Section 3.4.1 describes using the 3 most significant bits of the st_other
field to find out how many instructions there are between the local and global
entry point. This patch adds the correct offset required to branch to the local
entry point of a function.
Differential Revision: https://reviews.llvm.org/D45729
llvm-svn: 331046
The PPC64 V2 ABI restores the toc base by loading from an offset of 24 from r1.
This patch fixes the offset and updates the testcases from V1 to V2. It also
issues an error when a nop is missing after a call to an external function.
Differential Revision: https://reviews.llvm.org/D45892
llvm-svn: 330600
Now that we don't ICF synthetic sections, we can go back to the old
logic on whose responsibility it is to check Repl.
The idea is that Sec->something() will not check Repl. It is the
responsibility of the caller to find the correct Sec.
llvm-svn: 330346
We had a single symbol using -1 with a synthetic section. It is
simpler to just update its value.
This is not a big will by itself, but will allow having a simple
getOffset for InputSeciton.
llvm-svn: 330340
Using getOffset is here was a bit of an overkill. This is being
written and has relocations. This implies it is a .eh_frame or regular
section.
llvm-svn: 330307
This is similar to r329219, but for the entire section. Like r329219 I
don't expect this to have any real impact, it is just more consistent
and simpler.
llvm-svn: 329367
We were ignoring the addend if the piece was dead. I don't expect this
to make a difference in any real world situations, but it is simpler
anyway.
llvm-svn: 329219
In the lld perf builder r328686 had a negative impact in
stalled-cycles-frontend. Somehow that stat is not showing on my
machine, but the attached patch shows an improvement on cache-misses,
which is probably a reasonable proxy.
My working theory is that given a large input the pieces vector is out
of cache by the time initOffsetMap runs.
Both finalizeContents implementation have a convenient location for
initializing the OffsetMap, so this seems the best solution.
llvm-svn: 329117
OffsetMap maps to a SectionPiece index, but we were not taking
advantage of that in getSectionPiece.
With this patch both getOffset and getSectionPiece use OffsetMap and
the binary search is moved to findSectionPiece.
llvm-svn: 329044
Since SectionBase::getOutputSection handles ICF replaces and
SectionBase::getOffset was handling it in some cases, it is more
consistent to have getOffset always handle it.
llvm-svn: 328391
When looking for the output section and the output offset the
expectation was that the caller had looked at Repl. That works fine
for InputSections, but in the case of MergeInputSections the caller
doesn't have the section that is actually replaced.
The original testcase was failing because getOutputSection was
returning null. The slightly extended testcase also checks that
getOffset also checks Repl.
I will send a refactoring separetelly.
llvm-svn: 328332
Our code assumes all input sections in an output SHF_LINK_ORDER
section has SHF_LINK_ORDER flag. We do not check that and that can cause a crash.
That happens because we call
std::stable_sort(Sections.begin(), Sections.end(), compareByFilePosition);,
where compareByFilePosition predicate does not expect to see
null when calls getLinkOrderDep.
The same might happen when sections refer to non-regular sections.
Test cases demonstrate the issues, patch fixes them.
Differential revision: https://reviews.llvm.org/D44193
llvm-svn: 327006
Previously we would crash because did not mark .rel[a] sections
as dead and they tried to access parent which was not live
after ICF and therefore was null.
Differential revision: https://reviews.llvm.org/D43241
llvm-svn: 325877
Summary:
This follows up on r321889 where writing of Elf_Rel addends was partially
moved to RelocationBaseSection. This patch ensures that the addends are
always written to the output section when a input section uses RELA but the
output is REL.
Differential Revision: https://reviews.llvm.org/D42843
llvm-svn: 325328
Even though it doesn't make sense, there seems to be multiple programs
in the wild that create PC-relative relocations in non-ALLOC sections.
I believe this is caused by the negligence of GNU linkers to not report
any errors for such relocations.
Currently, lld emits warnings against such relocations and exits.
So, you cannot link any program that contains wrong relocations until
you fix an issue in a program that generates wrong ELF files. It's often
impractical to fix a program because it's not always easy.
This patch relaxes the error checking and emit a warning instead.
Differential Revision: https://reviews.llvm.org/D43351
llvm-svn: 325307
In order to identify a compressed section, we check if a section name
starts with ".zdebug" or the section has SHF_COMPRESSED flag. We already
use the knowledge in this function. So hiding that check in
isCompressedELFSection doesn't make sense.
llvm-svn: 324951
When decompressing a compressed debug section, we drop SHF_COMPRESSED
flag but we didn't drop "z" in ".zdebug" section name. This patch does
that for consistency.
This change also fixes the issue that .zdebug_gnu_pubnames are not
dropped when we are creating a .gdb_index section.
llvm-svn: 324949
Initially LLD generates Elf_Rel relocations for O32 ABI and Elf_Rela
relocations for N32 / N64 ABIs. In other words, format of input and
output relocations was always the same. Now LLD generates all output
relocations using Elf_Rel format only. It conforms to ABIs requirement.
The patch suggested by Alexander Richardson.
llvm-svn: 324064
We normally avoid "switch (Config->EKind)", but in this case I think
it is worth it.
It is only executed when there is an error and it allows detemplating
a lot of code.
llvm-svn: 321404
It is currently in InputSectionBase. Only InputSections are used in
ICF, so Repl should be move to InputSection to clear the class
hierarchy or, like this patch does, to SectionBase for convenience.
The convenience of having it on the base class is that we can just
access the replacement without having to first check if it is an
InputSection. It is a bit less code and a bit faster as some of this
code is very hot.
I got up to 1.77% improvement in clang-gdb-index and no regressions
according to lnt.
llvm-svn: 320654
Having a SectionBase method check Repl is inconsistent with how we
handle other section information.
For example, if a section is replaced, Sec->Live is false and it is
natural for Sec->getOutputSection() to be null.
It is the symbol that is moved to the replacement section.
llvm-svn: 320599
Since MarkLive.cpp is the place where we set Live flags for
other sections, it looks correct to do that there.
Benefit is that we stop spreading GC logic outsize of MarkLive.cpp.
Differential revision: https://reviews.llvm.org/D40454
llvm-svn: 319435
Simon Atanasyan