Add support for the R_ARM_THM relocations used in the objects present
in arm-linux-gnueabihf-gcc. These are:
R_ARM_THM_CALL
R_ARM_THM_JUMP11
R_ARM_THM_JUMP19
R_ARM_THM_JUMP24
R_ARM_THM_MOVT_ABS
R_ARM_THM_MOVW_ABS_NC
Interworking between ARM and Thumb is partially supported with BLX.
The R_ARM_CALL relocation for ARM instructions and R_ARM_THM_CALL
relocation for Thumb instructions will write out a BL or BLX depending
on the state of the Target.
Assumptions:
- Availability of BLX and extended range of Thumb 4-byte Branch
instructions.
- In relocateOne if (Val & 0x1) == 1 target is Thumb, 0 is ARM.
This will hold for objects that comply with the ABI for the
ARM architecture.
This is sufficient for hello world to work with a recent
arm-linux-gnueabihf distribution.
Limitations:
No interworking for R_ARM_JUMP24, R_ARM_THM_JUMP24, R_ARM_THM_JUMP19
and the deprecated R_ARM_PLT32 and R_ARM_PC24 instructions as these
cannot be written out as a BLX and need a state change thunk.
No range extension thunks. The R_ARM_JUMP24 and R_ARM_THM_CALL have a
range of 16Mb
llvm-svn: 272881
This should never happen with correct programs, but it is trivial
write a testcase where lld would crash or report duplicated
symbols. We now behave like when an archive is used and include the
file only once.
llvm-svn: 272724
Previously message told us that relocations could
not be used when making shared object. That was
correct because message could appear (and it is expected)
when we linked executable.
Message should have being changed to something
that says we can't use a subset of relocations against shared
symbols.
Patch fixes the text.
llvm-svn: 272478
Initially we wanted to check that these two relocations are not present when linking DSO because of
possible overflow in runtime. Patch moves them to writable segment in testcases to allow
proper error check to trigger.
Otherwise error message about using dynamic relocations against text segment was shown.
Differential revision: http://reviews.llvm.org/D21184
llvm-svn: 272379
It was reported in PR28020, that lld does not link code which
gold do. But in fact that is expected behavior as we do not
support DT_TEXTREL.
This patch changes error message as it can report about relocations against
text segments exclusively, other dynamic relocations errors can
be handled separately.
Differential revision: http://reviews.llvm.org/D21133
llvm-svn: 272377
We can now use this to decide whether to emit a verneed during the final
pass over the symbols. We were previously wrongly creating a verneed entry
in the case where all references to a DSO's symbols were weak.
In a future change we may also want to use the used bit to control whether
shared symbols are preemptible and appear in the dynsym. This seems a little
tricky to do at the moment because isNeeded() is templated.
The only other functional change here is that we emit a DT_NEEDED for DSOs
whose symbols are all preempted by objects that appear later in the link. But
that doesn't seem too important to me.
Differential Revision: http://reviews.llvm.org/D21171
llvm-svn: 272282
If the symbol is local we don't need to create a R_X86_64_DTPOFF64, we
can just write the correct value in the got.
Should fix pr28018.
llvm-svn: 272205
Previously this test performed check of binary data. Since
llvm-readobj currently able to dump all 3 types of version relative
sections, that can be used to make this test more transparent.
Patch do that.
Differential revision: http://reviews.llvm.org/D21024
llvm-svn: 272120
Add support for an ARM Target and the initial set of relocations
and PLT entries that are necessary for an ARM only hello world to
link. This has been tested against an ARM only sysroot from the
4.2.0 CodeSourcery Lite release.
Tests have been added to test/ELF for the support that has been
implemented.
Main limitations:
- No Thumb support
- Relocations incomplete
- No C++ exceptions support
- No TLS support
- No range extension or interworking veneer (thunk) support
- No Build Attribute support
- No Big-endian support
The deprecated relocations R_ARM_PLT32 and R_ARM_PC24 have been
implemented as these are used by the 4.2.0 CodeSourcery Lite release.
llvm-svn: 271993
This is mostly extracted from http://reviews.llvm.org/D18960.
The general idea for tlsdesc is that the two GD got entries are used
for a function pointer and its argument. The dynamic linker sets
both. In the non-dlopen case the dynamic linker sets the function to
the identity and the argument to the offset in the tls block.
All that the static linker has to do in the non-dlopen case is
relocate the code to point to the got entries and create a dynamic
relocation.
The dlopen case is more complicated, but can be implemented in another patch.
llvm-svn: 271569
Patch implements next relaxation from latest ABI:
"Convert memory operand of test and binop into immediate operand, where binop is one of adc, add, and, cmp, or,
sbb, sub, xor instructions, when position-independent code is disabled."
It is described in System V Application Binary Interface AMD64 Architecture Processor
Supplement Draft Version 0.99.8 (https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-r249.pdf,
B.2 "B.2 Optimize GOTPCRELX Relocations").
Differential revision: http://reviews.llvm.org/D20793
llvm-svn: 271405
When we undefine, we also preserve type of symbol so that we get
it right in the combined LTO object.
Differential Revision: http://reviews.llvm.org/D20851
llvm-svn: 271403
In case of MIPS, GP-relative relocations always resolve to a definition
in a regular input file, ignoring the one-definition rule. Such
relocations are used to setup GP relative offsets in a function's
prologue. So we, for example, should not attempt to create a dynamic
relocation even if the target symbol is preemptible.
Fixes bug 27880.
Differential Revision: http://reviews.llvm.org/D20664
llvm-svn: 271100
MIPS .reginfo and .MIPS.options sections are consumed by the linker, and
the linker produces a single output section. But it is possible that
input files contain section symbol points to the corresponding input
section. In case of generation a relocatable output we need to write
such symbols to the output file.
Fixes bug 27878.
Differential Revision: http://reviews.llvm.org/D20688
llvm-svn: 270910
D15779 introduced basic approach to support new relaxations.
This patch implements relaxations for jmp and call instructions,
described in System V Application Binary Interface AMD64 Architecture Processor
Supplement Draft Version 0.99.8 (https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-r249.pdf,
B.2 "B.2 Optimize GOTPCRELX Relocations")
Differential revision: http://reviews.llvm.org/D20622
llvm-svn: 270721
Add another possible error that may be reported for the same case. The
original reproduction case that prompted r270706 produced the error
"corrupted CIE" instead of "corrupted or unsupported CIE information".
The specific error depends on arbitrary data later in the file so
check that neither is emitted in case the input is ever changed.
Document the process used to create the input .o and rename the test
file to .s, as requested by Rafael.
llvm-svn: 270709
"A zero length string indicates that no augmentation data is present."
The FreeBSD/mips toolchain (GCC 4.2.1) generates .debug_frame sections
containing CIE records that have an empty augmentation string.
Differential Revision: http://reviews.llvm.org/D19928
llvm-svn: 270706
System V Application Binary Interface AMD64 Architecture Processor Supplement Draft Version 0.99.8
(https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-r249.pdf, B.2 "B.2 Optimize GOTPCRELX Relocations")
introduces possible relaxations for R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX.
That patch implements the next relaxation:
mov foo@GOTPCREL(%rip), %reg => lea foo(%rip), %reg
and also opens door for implementing all other ones.
Implementation was suggested by Rafael Ávila de Espíndola with few additions and testcases by myself.
Differential revision: http://reviews.llvm.org/D15779
llvm-svn: 270705
Previously, we created a .bss section when needed. We had a function
ensureBss() for that purpose. Turned out that was error-prone
because it was easy to forget to call that function before accessing
the .bss section.
This patch always make the BSS section. The section is added to the
output when it's not empty.
llvm-svn: 270527
Copy relocations are relocations to copy data from DSOs to
executable's .bss segment at runtime. It doesn't make sense to
create such relocations for zero-sized symbols.
GNU linkers don't agree with each other. ld rejects such
relocation/symbol pair. gold don't reject that but do not create
copy relocations as well. I took the former approach because
I don't think the latter is what user wants.
llvm-svn: 270525
Previously, EhFrameHdr section computed addresses to which FDEs are
applied to. This is not an ideal design because EhFrameHdr does not
know much about FDEs unless EhFrame passes the information to EhFrameHdr.
It is what we did.
This patch simplifies the code by making EhFrame to compute the
values and pass the cooked information to EhFrameHdr. EhFrameHdr no
longer have to know about the details of FDEs such as FDE encodings.
llvm-svn: 270393
This patch refactors EHOutputSection using SectionPiece struct.
EHRegion class was removed since we can now directly use SectionPiece.
An incomplete support of large CIE/FDE record (> 2^32 bytes) was removed
because it silently created broken executable. There are several places
in the existing code that "size" field is always 4 bytes and at offset 4
in the record, which is not true for 64-bit size records. We will have to
support that in future, but it is better to error out instead of creating
malformed eh_frame sections.
llvm-svn: 270382
the linker script. The cycle in the ELF/LinkerScript.cpp:assignAddresses()
routine will be used to go through all the sections and set all the
addresses correctly.
Add new test to check this case.
llvm-svn: 270090
Lazy binding is quite important for use case like a shared build of
llvm. Also, if someone wants to disable it, it is better done in the
compiler (disable plt generation).
The only reason to keep it is to make it easier to add a new
architecture. But it doesn't really help much as it is possible to start
with non lazy relocation and plt code but still let the generic part
create a dedicated .got.plt and .rela.plt.
llvm-svn: 269982
If you specify the option in the form of --build-id=0x<hexstring>,
that hexstring is set as a build ID. We observed that the feature
is actually in use in some builds, so we want this feature.
llvm-svn: 269495
The Elf_Rela has an explicit addend. It doesn't need the addend to be
written to the section being relocated.
Since relative relocations are very common in the output, this is a
noticeable speedup. The results I got were
chromium
master 4.778149487
patch 4.761120792 0.996436131802
chromium fast
master 1.896253636
patch 1.840990582 0.970856718241
the gold plugin
master 0.399337811
patch 0.392279276 0.982324401032
clang
master 0.666873675
patch 0.665895708 0.998533504865
llvm-as
master 0.037101095
patch 0.037123149 1.00059442989
the gold plugin fsds
master 0.422473396
patch 0.414192879 0.980399909016
clang fsds
master 0.747302008
patch 0.744843964 0.996710775599
llvm-as fsds
master 0.033146245
patch 0.033064531 0.997534743377
scylla
master 4.08857525
patch 4.082245184 0.998451767275
llvm-svn: 269417
Just do not allow to link shared library if there are
undefined symbols.
This fixes PR27447
Differential revision: http://reviews.llvm.org/D20169
llvm-svn: 269183
This is the option which sorts relocs to optimize dynamic linker performance.
-z combelocs is the default in gold, also it ignores -z nocombreloc,
this patch do the same.
Patch sorts relocations by symbols only and do not create any
DT_REL[A]COUNT entries. That is different with what gold/bfd do.
More information about option is here:
http://www.airs.com/blog/archives/186http://people.redhat.com/jakub/prelink.pdf, p.2
Differential revision: http://reviews.llvm.org/D19528
llvm-svn: 269066
MIPS N64 ABI packs multiple relocations into the single relocation
record. In general, all up to three relocations can have arbitrary types.
In fact, Clang and GCC uses only a few combinations. For now, we support
two of them. That is allow to pass at least all LLVM test suite cases.
<any relocation> / R_MIPS_SUB / R_MIPS_HI16 | R_MIPS_LO16
<any relocation> / R_MIPS_64 / R_MIPS_NONE
The first relocation is a 'real' relocation which is calculated using
the corresponding symbol's value. The second and the third relocations
used to modify result of the first one: extend it to 64-bit, extract
high or low part etc. For details, see part 2.9 'Relocation' at
https://dmz-portal.mips.com/mw/images/8/82/007-4658-001.pdf
llvm-svn: 268876
We were creating the copy relocations just fine, but then thinking that
the .bss position could be preempted and creating a dynamic relocation
to it, which would crash at runtime since that memory is read only.
llvm-svn: 268668
This allows the combined LTO object to provide a definition with the same
name as a symbol that was internalized without causing a duplicate symbol
error. This normally happens during parallel codegen which externalizes
originally-internal symbols, for example.
In order to make this work, I needed to relax the undefined symbol error to
only report an error for symbols that are used in regular objects.
Differential Revision: http://reviews.llvm.org/D19954
llvm-svn: 268649
We were previously using an output offset of -1 for both GC'd and tail
merged pieces. We need to distinguish these two cases in order to filter
GC'd symbols from the symbol table -- we were previously asserting when we
asked for the VA of a symbol pointing into a dead piece, which would end
up asking the tail merging string table for an offset even though we hadn't
initialized it properly.
This patch fixes the bug by using an offset of -1 to exclusively mean GC'd
pieces, using 0 for tail merges, and distinguishing the tail merge case from
an offset of 0 by asking the output section whether it is tail merge.
Differential Revision: http://reviews.llvm.org/D19953
llvm-svn: 268604
It is insanely hard to write a test that works both on Windows and Unix.
I tried to workaround it with cpio's minor options, but the behaviors of
the options were myterious. It just doesn't worth to spend time on it.
And probably minor options could break buildbots that doesn't have the
GNU version of cpio command.
In this patch, I simply added a separate test file that runs only on
Windows.
llvm-svn: 268596
MIPS N64 ABI packs multiple relocations into the single relocation
record. Particularly it requires to represent dynamic relative
relocation as a combination of R_MIPS_REL32 and R_MIPS_64 relocations.
llvm-svn: 268565
We were already checking for non relative relocations.
If we ever decide to add support for rw text segments this means we will
have a single spot to add the flag.
llvm-svn: 268558
Currently we don't check when creating relative relocations if the
section is read only or not. I am about to fix that, so first update the
patches that depend on the current behavior.
llvm-svn: 268542
These relocations introduced by MIPS N64 ABI. R_MIPS_GOT_DISP references
GOT entry with full symbol's address, R_MIPS_GOT_PAGE creates GOT entry
with address of memory page which includes symbol's address,
R_MIPS_GOT_OFST used together with R_MIPS_GOT_PAGE. This relocation
calculates offset from beginning of memory page to the symbol address.
llvm-svn: 268525
As requested by Rafael Espindola in his post-commit comments on r268036. This
makes the previous behaviour the default while still allowing verification of
IAS.
llvm-svn: 268496
MIPS N64 ABI introduces .MIPS.options section which specifies miscellaneous
options to be applied to an object/shared/executable file. LLVM as well as
modern versions of GNU tools read and write the only type of the options -
ODK_REGINFO. It is exact copy of .reginfo section used by O32 ABI.
llvm-svn: 268485
Both bfd and gold have this. It allows disabling build-id when it is the
default with by adding -Wl,--build-id=none no the clang command line.
llvm-svn: 268435
Introduce a special symbol type to indicate that we have not yet seen a type
for the symbol, so we should not report TLS mismatches for that symbol.
Differential Revision: http://reviews.llvm.org/D19836
llvm-svn: 268411
We want --reproduce to
* not rewrite scripts and thin archives
* work with absolute paths
Given that, it pretty much has to create a full directory tree. On windows that
is problematic because of the very short maximum path limit. On most cases
users can still work around it with "--repro c:\r", but that is annoying and
not viable for automated testing.
We then need to produce some form of archive with the files. The first option
that comes to mind is .a files since we already have code for writing them.
There are a few problems with them
The format has a dedicated string table, so we cannot start writing it until
all members are known.
Regular implementations don't support creating directories. We could make
llvm-ar support that, but that is probably not a good idea.
The next natural option would be tar. The problem is that to support long path
names (which is how this started) it needs a "pax extended header" making this
an annoying format to write.
The next option I looked at seems a natural fit: cpio files.
They are available on pretty much every unix, support directories and long path
names and are really easy to write. The only slightly annoying part is a
terminator, but at least gnu cpio only prints a warning if it is missing, which
is handy for crashes. This patch still makes an effort to always create it.
llvm-svn: 268404
The test is now unexpectedly passing on
llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast which is treated as an error.
For now, disable Windows testing of the feature.
Rafael is working on generating an archive, which will hopefully allow
us to turn this test back on.
Unfortunately, we don't have a way to temporarily XFAIL this test just
on llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast.
llvm-svn: 268351
Weak undefined symbols resolve to the image base. This is a little strange,
but it allows us to link function calls to such symbols. Normally such a
call will be guarded with a comparison, which will load a zero from the GOT.
There's one example of such a function call in crti.o in Linux's CRT.
As part of this change, I also needed to make the synthetic start and end
symbols image base relative in the case where their sections were empty,
so that PC-relative references to those symbols would continue to work.
Differential Revision: http://reviews.llvm.org/D19844
llvm-svn: 268350
`REQUIRES: shell` is not appropriate because that would mean that there
are no windows bots testing this, and that is precisely where it needs
the most testing.
Rafael or Rui are working on generating an archive directly, which
should avoid this issue.
We can try to move the bot to a shorter build directory path.
llvm-svn: 268345
This patch increases the size of Undefined by the size of a pointer,
but it wouldn't actually increase the size of memory that LLD uses
because we are not allocating the exact size but the size of the
largest SymbolBody.
llvm-svn: 268310
Rafael Espindola