The patch fixes two related problems:
- If CIE augmentation string has 'L' token the CIE contains a byte
defines LSDA encoding. We should skip this byte in `getFdeEncoding`
routine. Before this fix we do not skip it and if the next token
is 'R' treat this byte as FDE encoding.
- FDE encoding format has separate flags e.g. DW_EH_PE_pcrel for
definition of relative pointers. We should add .eh_frame address to
the PC value iif the DW_EH_PE_pcrel is specified.
http://www.airs.com/blog/archives/460
There is one more not fixed problem in this code. If PC value is encoded
using signed relative format e.g. DW_EH_PE_sdata4 | DW_EH_PE_pcrel we
should sign extend result of read32 to perform calculation correctly.
I am going to fix that in a separate patch.
Differential Revision: http://reviews.llvm.org/D17733
llvm-svn: 262461
CoreDriver implements a driver for a hypothetical platform.
It is intended to be used in unittests. However, it is actually
redundant because the features are tested using the real driver
for the real platforms. So we can remove this.
http://reviews.llvm.org/D17698
llvm-svn: 262421
__start_/__end_ <section-name> symbols and other specials like:
preinit_array_start/end
init_array_start/end
fini_array_start/end
should not be created by linker when creating relocatable files.
Differential revision: http://reviews.llvm.org/D17774
llvm-svn: 262366
BSD linker scripts contain special cases to add NOP
padding to code sections. Syntax is next:
.init:
{
KEEP (*(.init))
} =0x90909090
(0x90 is NOP)
This patch implements that functionality.
llvm-svn: 262020
https://docs.oracle.com/cd/E53394_01/html/E54766/u-etext-3c.html
It is said that:
_etext - The address of _etext is the first
location after the last read-only loadable segment.
_edata - The address of _edata is the first
location after the last read-write loadable segment.
_end - If the address of _edata is greater than the address
of _etext, the address of _end is same as the address of _edata.
In real life _end and _edata has different values for that case.
Both gold/bfd set _edata to the end of the last non SHT_NOBITS section.
This patch do the same for consistency.
It should fix the https://llvm.org/bugs/show_bug.cgi?id=26729.
Differential revision: http://reviews.llvm.org/D17601
llvm-svn: 262019
For shared libraries we allow any weak undefined symbol to eventually be
resolved, even if we never see a definition in another .so. This matches
the behavior when handling other undefined symbols in a shared library.
For executables, we require seeing a definition in a .so or resolve it
to zero. This is also similar to how non weak symbols are handled.
llvm-svn: 262017
R_MIPS_GOT16 relocation against local symbol requires index of a local
GOT entry which contains page address corresponds to sum of the symbol
address and addend. The addend in that case is calculated using addends
from the R_MIPS_GOT16 and paired R_MIPS_LO16 relocations.
Differential Revision: http://reviews.llvm.org/D17610
llvm-svn: 261930
This patch implements the same algorithm as LLD/COFF's ICF. I'm
not going to repeat the same description about how it works, so you
want to read the comment in ICF.cpp in this patch if you want to know
the details. This algorithm should be more powerful than the ICF
algorithm implemented in GNU gold. It can even merge mutually-recursive
functions (which is harder than one might think).
ICF is a fairly effective size optimization. Here are some examples.
LLD: 37.14 MB -> 35.80 MB (-3.6%)
Clang: 59.41 MB -> 57.80 MB (-2.7%)
The lacking feature is "safe" version of ICF. This merges all
identical sections. That is not compatible with a C/C++ language
requirement that two distinct functions must have distinct addresses.
But as long as your program do not rely on the pointer equality
(which is in many cases true), your program should work with the
feature. LLD works fine for example.
GNU gold implements so-called "safe ICF" that identifies functions
that are safe to merge by heuristics -- for example, gold thinks
that constructors are safe to merge because there is no way to
take an address of a constructor in C++. We have a different idea
which David Majnemer suggested that we add NOPs at beginning of
merged functions so that two or more pointers can have distinct
values. We can do whichever we want, but this patch does not
include neither.
http://reviews.llvm.org/D17529
llvm-svn: 261912
-r, -relocatable - Generate relocatable output
Currently does not have support for files containing
relocation sections with entries that refer to local
symbols (like rel[a].eh_frame which refer to sections
and not to symbols)
Differential revision: http://reviews.llvm.org/D14382
llvm-svn: 261838
This commit does two related thing. At first, it enumerates supported
absolute MIPS relocations in the `MipsTargetInfo<ELFT>::isRelRelative`
method. In that case the code is shorter and the case switch does not
tend to grow. At second, it prevents R_MIPS_COPY and PLT creation for
relative relocations. For almost all relative MIPS relocations like
R_MIPS_PC19_S2, R_MIPS_PCHI16 etc it does not have a sence. The only
exception is R_MIPS_PC32. GNU linker creates a copy relocation or PLT
entry for it. But I could not find any real test case uses R_MIPS_PC32
with DSO defined symbol as a target. So for now I prefer to skip this
case to simplify the LLD code.
llvm-svn: 261822
This test is flaky for more than half a year or so on buildbots
and has been causing confusion. Remove it while I'm investing the
cause.
llvm-svn: 261709
There is nothing aarch64 specific in here. If a symbol can be preempted,
we need to copy the full relocation to the dynamic linker.
If a symbol cannot be preempted, we can make the dynamic linker life
easier and produce a relative relocation.
This is directly equivalent to R_X86_64_64 to R_x86_64_RELATIVE
conversion.
llvm-svn: 261678
The .tbss section is in the middle of a PT_LOAD. Whatever treatment we
give to its address we must also give to the offset.
We were ignoring it for address computations, but not for offset.
Fixes pr26712.
llvm-svn: 261667
This patch moves BitcodeFile instantiation into createObjectFile.
Previously, we handle bitcode files outside that function and did
not handle for --whole-archive.
http://reviews.llvm.org/D17527
llvm-svn: 261663
This patch fixes the R_AARCH64_ABS64 relocation when used in shared mode,
where it requires a dynamic R_AARCH64_RELATIVE relocation. To correct set
the addend on the dynamic relocation (since it will be used by the dynamic
linker), a new TargetInfo specific hook was created (getDynRelativeAddend)
to get the correct addend based on relocation type.
The patch fixes the issues when creating shared library code against
{init,fini}_array, where it issues R_AARCH64_ABS64 relocation against
local symbols.
llvm-svn: 261651
When link-time garbage collection is in use (-gc-sections), it is
often useful to mark sections that should not be eliminated.
This is accomplished by surrounding an input section's wildcard
entry with KEEP(). Patch implements that command.
Differential revision: http://reviews.llvm.org/D17242
llvm-svn: 261616
A weak undefined should not fetch archive members, so we have to keep
the Lazy symbol.
That means the lazy symbol has to encode information about the original
weak undef.
Fixes pr25762.
llvm-svn: 261591
This reduces the .rodata of scyladb from 4501932 to 4334639 bytes (1.038
times smaller).
I don't think it is critical to support tail merging, just exact
duplicates, but given the code organization it was actually a bit easier
to support both.
llvm-svn: 261327
Each rule in SECTIONS commands is something like ".foo *(.baz.*)",
which instructs the linker to collect all sections whose name matches
".baz.*" from all files and put them into .foo section.
Previously, we didn't recognize the wildcard character. This patch
adds that feature.
Performance impact is a bit concerning because a linker script can
contain hundreds of SECTIONS rules, and doing pattern matching against
each rule would be too expensive. We could merge all patterns into
single DFA so that it takes O(n) to the input size. However, it is
probably too much at this moment -- we don't know whether the
performance of pattern matching matters or not. So I chose to
implement the simplest algorithm in this patch. I hope this simple
pattern matcher is sufficient.
llvm-svn: 260745
This patch adds some TLS relocations and relaxations for AArch64.
Some Global-Dynamic relocation are handled by optimizing them to
Local-Exec (Initial-Exec is not yet supported). They are:
- R_AARCH64_TLSDESC_ADR_PAGE21
- R_AARCH64_TLSDESC_LD64_LO12_NC
- R_AARCH64_TLSDESC_ADD_LO12_NC
- R_AARCH64_TLSDESC_CALL
Also some Init-Exec is optimized to Local-Exec if possible. They are:
- R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21
- R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC
Finally some Local-Exec relocation are handled in relocateOne:
- R_AARCH64_TLSLE_ADD_TPREL_HI12
- R_AARCH64_TLSLE_ADD_TPREL_LO12_NC
This work is mainly for compiler bootstrap, where static binaries is
showing good progress (although shared object still lacking support
from both TLS aarch64 backend and some other issues).
llvm-svn: 260677
Previously, if both A and B are ".ctors", both compCtors(A, B) and
compCtors(B, A) are true, which is a violation of the strict weak
ordering because such function is not antisymmetric.
llvm-svn: 260633
They don't count for the memory or file size, so this is mostly just a
simplification.
The only noticeable difference should be fewer empty program headers.
llvm-svn: 260465
Global constructors and destructors are guaranteed to be called
in the order as they appear in a translation unit. So we don't want
to mess up the order if they have the same priority.
llvm-svn: 260463
The patch adds lazy relocation support for MIPS and R_MIPS_26 relocation
handing.
R_MIPS_26 relocation might require PLT entry creation. In that case it
is fully supported by the patch. But if the relocation target is a local
symbol we need to use a different expression to calculate the relocation
result. This case is not implemented yet because there is no method to
get know the kind of relocation target in the `relocateOne` routine.
Differential Revision: http://reviews.llvm.org/D16982
llvm-svn: 260424
The non lazy atoms generated in the stubs pass use an image cache to
hold all of the pointers. On arm archs, this is the __got section,
but on x86 archs it should be __nl_symbol_ptr.
rdar://problem/24572729
llvm-svn: 260271
ld64 aligns most of the stub's to 2 byte alignment, expect for
the stub helper common atoms which are 4 byte aligned.
This adds a new field to StubInfo which tracks this alignment
and ensures that this is the alignment we get in the final image.
rdar://problem/24570220
llvm-svn: 260248
This is the function equivalent of a copy relocation.
Since functions are expected to change sizes, we cannot use copy
relocations. In situations where one would be needed, what is done
instead is:
* Create a plt entry
* Output an undefined symbol whose addr is the plt entry.
The dynamic linker makes sure any shared library uses the plt entry as
the function address.
llvm-svn: 260224
Also added the defaults for whether to generate this load command, which
the cmdline options are able to override.
There was also a difference to ld64 which is fixed here in that ld64 will
generate an empty data in code command if requested.
rdar://problem/24472630
llvm-svn: 260191
This load command generates data in the LINKEDIT section which
is a list of ULEB128 delta's to all of the functions in the __text section.
It is then 0 terminated and pointer aligned to pad.
ld64 exposes the -function-starts and no-function-starts cmdline options
to override behaviour from the defaults based on file types.
rdar://problem/24472630
llvm-svn: 260188
This was a bug in our handling of these symbols compared to ld64.
Turns out that ld64 always marks these symbols as being not dead stripped.
llvm-svn: 260185
The initial segment protection was also being used to set the maximum
segment protection level. Instead, the maximum should be set according
to the architecture we are linking. For example on Mac OS it should be
RWX on most pages, but on iOS is often on R_X.
rdar://problem/24515136
llvm-svn: 259966
I removed "CIE/FIE size is too large" error because that was not
checking for correct error conditions. [UINT_MAX - 4, UINT_MAX) is
a correct range as a size of a CIE/FDE record. It's just that the
size cannot be larger than the section size.
llvm-svn: 259951
Summary:
LLVM3.3 (and earlier) would fail to include a relocation section in
the group that the section it was relocating is in. Object files
affected by this issue have been encountered in the wild when using LLD.
This would result in a siutation like:
Section {
Index: 5
Name: .text._Z3fooIiEvv (6)
Type: SHT_PROGBITS (0x1)
Flags [ (0x206)
SHF_ALLOC (0x2)
SHF_EXECINSTR (0x4)
SHF_GROUP (0x200)
]
Address: 0x0
Offset: 0x48
Size: 5
Link: 0
Info: 0
AddressAlignment: 1
EntrySize: 0
}
Section {
Index: 6
Name: .rela.text._Z3fooIiEvv (1)
Type: SHT_RELA (0x4)
Flags [ (0x0)
]
Address: 0x0
Offset: 0x3F0
Size: 24
Link: 8
Info: 5
AddressAlignment: 8
EntrySize: 24
}
In LLD, during symbol resolution, we discard the section containing the
weak symbol, but this amounts to replacing it with
InputSection<ELFT>::Discarded.
When we later saw the corresponding relocation section, we would then
end up pusing onto InputSection<ELFT>::Discarded.RelocSections, which is
bogus.
Reviewers: ruiu, rafael
Subscribers: llvm-commits, Bigcheese
Differential Revision: http://reviews.llvm.org/D16898
llvm-svn: 259831
On Mac OS 10.5 and later, with X86_64 and outputting a dynamic executable,
ld64 set the CPU_SUBTYPE_LIB64 mask on the cpusubtype in the mach_header.
This adds the same functionality to lld.
rdar://problem/24507177
llvm-svn: 259826
If relocation against symbol requires GOT entry creation and this symbol
is defined in DSO, the GOT entry should be created in the 'global' part
of the GOT even if we link executable file. Also we do not need to create
a dynamic symbol table entry for global symbol corresponding to the
local GOT entry.
llvm-svn: 259778
ld64 sets both S_ATTR_PURE_INSTRUCTIONS and S_ATTR_SOME_INSTRUCTIONS
on __TEXT, __text. We only had the S_ATTR_PURE_INSTRUCTIONS attribute.
rdar://problem/24495801
llvm-svn: 259744
In the case where we are emitting to an object file, the platform is
possibly unknown, and the source object files contained load commands
for version min, we can take the maximum of those min versions and
emit in in the output object file.
This test also tests r259739.
llvm-svn: 259742
This option is emitted in the min_version load commands.
Note, there's currently a difference in behaviour compared to ld64 in
that we emit a warning if we generate a min_version load command and
didn't give an sdk_version. We need to decide what the correct behaviour
is here as its possible we want to emit an error and force clients to
provide the option.
llvm-svn: 259729
If the command line contains something like -macosx_version_min and we
don't explicitly disable generation with -no_version_load_command then
we generate the LC_VERSION_MIN command in the output file.
There's a couple of FIXME's in here. These will be handled soon with
more tests but I didn't want to grow this patch any more than it already was.
rdar://problem/24472630
llvm-svn: 259718
On some Windows environment, this test did not fail, because opening NUL
with FileOutputBuffer didn't fail. Thanks to George Rimar for reporting.
llvm-svn: 259669
It can fail to open an output file for various reasons, including
lack of permission, too long filename, or the output file is not
a mmap'able file.
llvm-svn: 259596
In r259574 I fixed some of the issues with the mach header symbols
and DSO handles.
This is the next issue whereby the __mh_execute_header has to not
be dead stripped, and (to match ld64) should be dynamically referenced.
The test here should also have been added in r259574 to make sure that
we emit this symbol. But checking that it is not only emitted but also
has the correct reference type is fine.
llvm-svn: 259589
The magic file which contained these symbols inherited from archive
which meant that the resolver didn't add the required atoms as archive
members only get added when referenced. Instead we now inherit from
SimpleFile which always links in the atoms needed.
The second issue was in the handling of these symbols when we emit
the MachO. The mach header symbol needs to be in the atom list as
it gets an offset (0), and being in the atom list makes sure it is
emitted to the symbol table. DSO handles are not emitted to the
symbol table.
rdar://problem/24450654
llvm-svn: 259574
Previously, we used both single quotes and double quotes, and
some single-quoted tokens are concatenated with next tokens because
there were no spaces between them. That may be a cause of test flakiness
on Windows, which is reported as https://llvm.org/bugs/show_bug.cgi?id=26388.
The new test commands are more straightforward than before.
llvm-svn: 259559
This patch adds "Error" field to LinkerScript class. That field
is false by default, and set to true if there is a syntax error
in an input file. The linker script parser is a recursive-descedent
parser. Each function returns if Error is true -- so that
eventually the whole parser returns to a caller.
http://reviews.llvm.org/D16667
llvm-svn: 259557
-Bsymbolic-functions:
When creating a shared library, bind references to global
function symbols to the definition within the shared library, if any.
This patch also fixed behavior of already existent -Bsymbolic:
previously PLT entries were created even if -Bsymbolic was specified.
Differential revision: http://reviews.llvm.org/D16411
llvm-svn: 259481
Some dynamic table tags like RELSZ and PLTRELSZ depens on result of
finalizing corresponding relocation sections. Therefore we have to
finalize .dynamic section at the end.
Differential Revision: http://reviews.llvm.org/D16799
llvm-svn: 259478
If object files are drawn from archive files, the error message should
be something like "conflict symbols in foo.a(bar.o) and baz.o" instead
of "conflict symbols in bar.o and baz.o". This patch implements that.
llvm-svn: 259475
When we parse a MachoFile, we set a number of members from the parsed
file, for example, subsectionsViaSymbols.
However, a number of passes, such as ObjCPass, create local copies of
MachoFile and don't get the benefit of setting flags and other fields in
the parser. Instead we can just give a more sensible default as the parser
will definitely get the correct value from the file anyway.
llvm-svn: 259426
__DATA, __objc_catlist contains a list of pointers to categories.
We want to atomize it so that the ObjC pass can later optimize and remove
categories. That will be a later patch.
llvm-svn: 259386
This avoids the need to have reserve and addString in sync.
We avoid hashing the global symbols again. This means that we don't
merge a global symbol that has the same name as some other string, but
that doesn't seem very common. The string table size is the same in
clang an scylladb with or without hashing global symbols again.
llvm-svn: 259136
Main executable did not export symbols that exist both in the main executable and in DSOs before this patch.
Symbols from object files that override symbols in DSO should be added to .dynsym table.
Differential revision: http://reviews.llvm.org/D16405
llvm-svn: 258672
There was an off by one error because the StringRef.substr functions
second argument is a length, not the end index.
Also updated a few ELF files which failed when run on Jenkins with paths
including the @ character. This is often used in Jenkins for shared
workspace plugin.
Reviewed by Rui Ueyama
llvm-svn: 258583
This option matches the behaviour of ld64, that is it prevents globals
from being dead stripped in executables and dylibs.
Reviewed by Lang Hames
Differential Revision: http://reviews.llvm.org/D16026
llvm-svn: 258554
Some MIPS relocation (for now R_MIPS_GOT16) requires creation of GOT
entries for symbol not included in the dynamic symbol table. They are
local symbols and non-local symbols with 'local' visibility. Local GOT
entries occupy continuous block between GOT header and regular GOT
entries.
The patch adds initial support for handling local GOT entries. The main
problem is allocating local GOT entries for local symbols. Such entries
should be initialized by high 16-bit of the symbol value. In ideal world
there should be no duplicated entries with the same values. But at the
moment of the `Writer::scanRelocs` call we do not know a value of the
symbol. In this patch we create new local GOT entry for each relocation
against local symbol, though we can exhaust GOT quickly. That needs to
be optimized later. When we calculate relocation we know a final symbol
value and request local GOT entry index. To do that we maintain map
between addresses and local GOT entry indexes. If we start to calculate
relocations in parallel we will have to serialize access to this map.
Differential Revision: http://reviews.llvm.org/D16324
llvm-svn: 258388
This pass currently emits an objc image info section if one is required.
This section contains the aggregated version and flags for all of the input
files.
llvm-svn: 258197
Like arch, os, etc, when we know we are going to use a file, we check
that the file has compatible objc constraints to the context, throw
appropriate errors where that is not the case, and hopefully set the
objc constraints on the context for use later.
Added 2 tests to ensure that we don't have incompatibilities between
host and simulator code as both will get x86 based architectures.
llvm-svn: 258173
When generating a relocatable file, its only valid to set this flag if
all of the inputs also had the flag. Otherwise we may atomize incorrectly
when we link the relocatable file again.
Reviewed by Lang Hames.
Differential Revision: http://reviews.llvm.org/D16018
llvm-svn: 257976
The image info struct contains flags for what kind of GC/retain/release is required.
Give an error if we parse GC flags as these are unsupported.
llvm-svn: 257974
This file was failing to build with asan enabled. The reason being that
applyFixupFinal was writing 4-bytes worth of fixup in to an atom only
a single byte in length.
The test case didn't actually need this particular reloc so i've removed
it, although i'll follow up with future commits to actually verify that
relocs are to an address with enough space for the fixup to be applied.
llvm-svn: 257906
Added check for terminator CIE/FDE which has zero data size.
void EHOutputSection<ELFT>::addSectionAux(
...
// If CIE/FDE data length is zero then Length is 4, this
// shall be considered a terminator and processing shall end.
if (Length == 4)
break;
...
After this "Bug 25923 - lld/ELF2 linked application crashes if exceptions were used." is fixed for me. Self link of clang also works.
Initial commit message:
[ELF] - implemented --eh-frame-hdr command line option.
--eh-frame-hdr
Request creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME" segment header.
Both gold and the GNU linker support an option --eh-frame-hdr which tell them to construct a header for all the .eh_frame sections. This header is placed in a section named .eh_frame_hdr and also in a PT_GNU_EH_FRAME segment. At runtime the unwinder can find all the PT_GNU_EH_FRAME segments by calling dl_iterate_phdr.
This section contains a lookup table for quick binary search of FDEs.
Detailed info can be found here:
http://www.airs.com/blog/archives/462
Differential revision: http://reviews.llvm.org/D15712
llvm-svn: 257889
This patch makes use of the handleLoadedFile hook added in r257814.
That method is used to check the arch and the OS of the files we are linking
against the arch and OS on the context.
The first test to use this ensures that we do not try to combine i386 Mac OS code
with i386 simulator code.
llvm-svn: 257837
MIPS ABI has relocations like R_MIPS_JALR which is just a hint for
linker to make some code optimization. Such relocations should not be
handled as a regular ones and lead to say dynamic relocation creation.
The patch introduces new virtual `Target::isHintReloc` method, overrides
it in the `MipsTargetInfo` class and calls it in the `Writer<ELFT>::scanRelocs`
method.
Differential Revision: http://reviews.llvm.org/D16193
llvm-svn: 257798
--eh-frame-hdr
Request creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME" segment header.
Both gold and the GNU linker support an option --eh-frame-hdr which tell them to construct a header for all the .eh_frame sections. This header is placed in a section named .eh_frame_hdr and also in a PT_GNU_EH_FRAME segment. At runtime the unwinder can find all the PT_GNU_EH_FRAME segments by calling dl_iterate_phdr.
This section contains a lookup table for quick binary search of FDEs.
Detailed info can be found here:
http://www.airs.com/blog/archives/462
Differential revision: http://reviews.llvm.org/D15712
llvm-svn: 257753
Fix: Added missed input file.
Initial commit message:
[ELF/AArch64] - Implemented R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 and R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC relocations
* R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 is calculated as Page(G(GTPREL(S+A))) – Page(P), set an ADRP immediate field to bits [32:12] of X; check –2^32 ≤ X < 2^32;
* R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC is calculated as G(GTPREL(S+A)), set an LD offset field to bits [11:3] of X. No overflow check; check that X&7 = 0.
Differential revision: http://reviews.llvm.org/D16117
llvm-svn: 257596
* R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 is calculated as Page(G(GTPREL(S+A))) – Page(P), set an ADRP immediate field to bits [32:12] of X; check –2^32 ≤ X < 2^32;
* R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC is calculated as G(GTPREL(S+A)), set an LD offset field to bits [11:3] of X. No overflow check; check that X&7 = 0.
Differential revision: http://reviews.llvm.org/D16117
llvm-svn: 257588
MIPS _gp_disp designates offset between start of function and gp pointer
into GOT therefore any relocations against it do not require dynamic
relocation.
llvm-svn: 257492
On Windows different versions of 'sed' work in different text/binary
mode by default. If default mode is text, sed produces corrupted binary
files. Unfortunately there is no standard command line option to select
the mode. Some 'sed' support '-b' to switch to binary mode, while other
ones support '--text' option and does not have '-b' option at all.
llvm-svn: 257471
On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
start of function and gp pointer into GOT. To make seal with such symbol
we add new method addIgnoredStrong(). It adds ignored symbol with global
binding to prevent the symbol substitution. The addIgnored call is not
enough here because this call adds a weak symbol which might be
substituted by symbol from shared library.
Differential Revision: http://reviews.llvm.org/D16084
llvm-svn: 257449
Summary: This is no longer needed now that the new ELF implementation supports AMDGPU.
Reviewers: ruiu, rafael
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D15954
llvm-svn: 257390
R_AARCH64_TSTBR14 is calculated as S+A-P,
Set the immediate field of a TBZ/TBNZ instruction to bits [15:2] of X; check -2^15 ≤ X < 2^15
Differential revision: http://reviews.llvm.org/D15824
llvm-svn: 257334
R_AARCH64_CONDBR19 is calculated as S+A-P,
Set the immediate field of a conditional branch instruction to bits [20:2] of X; check -2^20 ≤ X< 2^20.
Afaik there is no document for AARCH64 instruction encoding from official for unknown reason, so
I used gold source code and next link as a reference for implementation: http://kitoslab-eng.blogspot.ru/2012/10/armv8-aarch64-instruction-encoding.html. From which is clear that immediate field of a conditional branch instruction is 5 bits off. That is proved by output which is is equal to gold/bfd now.
Differential revision: http://reviews.llvm.org/D15809
llvm-svn: 257333
* Added instructions to generate R_X86_64_32 relocations. Without that next part of code was uncovered by test, code worked without it:
bool X86_64TargetInfo::relocNeedsPlt(uint32_t Type, const SymbolBody &S) const {
if (needsCopyRel(Type, S))
return false;
* Removed -e main, added _start
Differential revision: http://reviews.llvm.org/D15714
llvm-svn: 257331
DLL export tables usually contain dllexport'ed symbol RVAs so that
applications which use the DLLs can find symbols from the DLLs.
However, there's a minor feature to "forward" DLL symbols to other
DLLs.
If you set an RVA to a string whose form is "<dllname>.<symbolname>"
(e.g. "KERNEL32.ExitProcess") instead of symbol RVA to the export
table, the loader interprets that as a forwarder symbol, and resolve
that symbol from the specified DLL.
This patch implements that feature.
llvm-svn: 257243
It wasn't actually pointing to the function at the start of the text section, and so the offset in the binary differed when we passed the file through a second time.
The __eh_frame section uses implicit relocations and when reducing this test case from explicit to implicit, I got
the offset wrong. This makes sure it is correct.
llvm-svn: 257101
The __eh_frame section contains relocations which can always be implicitly generated.
This patch tracks whether sections have only implicitly relocations and skips emitting them to the object file if that is the case.
The test case here ensures that this is the case for __eh_frame sections.
Reviewed by Lang Hames.
http://reviews.llvm.org/D15594
llvm-svn: 257099
In this patch, all symbols are resolved normally and then wrap options
are applied. Renaming is implemented by mutating `Body` pointers of
Symbols. (As a result, Symtab.find(SymbolName)->getName() may return
a string that's different from SymbolName, but that is by design.
I designed the symbol and the symbol table to allow this kind of
operations.)
http://reviews.llvm.org/D15896
llvm-svn: 257075
Summary: This will allow us to remove the AMDGPU support from old ELF.
Reviewers: rafael, ruiu
Differential Revision: http://reviews.llvm.org/D15895
llvm-svn: 257023
String tables in unstripped executable files are fairly large in size.
For example, lld's executable file is about 34.4 MB in my environment,
and of which 3.5 MB is the string table. Efficiency of string table
construction matters.
Previously, the string table was built in an inefficient way. We used
StringTableBuilder to build that and enabled string tail merging,
although tail merging is not effective for the symbol table (you can
only make the string table 0.3% smaller for lld.) Tail merging is
computation intensive task and slow.
This patch eliminates string tail merging.
I changed the way of adding strings to the string table in this patch
too. Previously, strings were added using add() and the same strings
were then passed to getOffset() to get their offsets in the string table.
In this way, getOffset() needs to look up a hash table to get offsets
for given strings. This is a violation of "we look up the symbol table
(or a hash table) only once for each symbol" dogma of the new LLD's
design. Hash table lookup for long C++ mangled names is slow.
I eliminated that lookup in this patch.
In total, this patch improves link time of lld itself about 12%
(3.50 seconds -> 3.08 seconds.)
llvm-svn: 257017
The fixup content we encode here should be the offset from the
fixup location back to the last nonlocal label. We were only encoding
the address of the fixup, and not taking in to account the base address
of the atom we are in.
Updated the test case here to have a text section which will come before
the data section where the relocation lives. .data being at offset 0 had
previously been hiding this bug.
llvm-svn: 256974
The final section order in relocatable files was just a side effect
of the atom sorter. This meant that sections like __data were before
__text because __data has RW permissions and __text RX and RW was less
than RX in our enum.
Final linked images had an actual section/segment sorter. There was no
reason for the difference, so simplify a bunch of code and just use the
same sorted for everything.
Reviewed by Lang Hames.
http://reviews.llvm.org/D15868
llvm-svn: 256786
Test did not catch this either, so I`ll improve it and recommit later.
Original commit message:
[ELF] - Optimize .eh_frame section: remove CIE if all FDEs referencing it were removed.
This patch performs little optimization for eh_frame section.
If all FDE`s that referenced CIE are removed then CIE is also removed from output.
That can happen for example when dropping FDEs that point to dropped sections. Testcase showing that is included.
The same optimization was added to ld about 14 years ago: https://sourceware.org/ml/binutils/2001-12/msg00144.html, gold does not do that it seems.
Differential revision: http://reviews.llvm.org/D15564
llvm-svn: 256693
This patch performs little optimization for eh_frame section.
If all FDE`s that referenced CIE are removed then CIE is also removed from output.
That can happen for example when dropping FDEs that point to dropped sections. Testcase showing that is included.
The same optimization was added to ld about 14 years ago: https://sourceware.org/ml/binutils/2001-12/msg00144.html, gold does not do that it seems.
Differential revision: http://reviews.llvm.org/D15564
llvm-svn: 256638
The R_MIPS_GPREL16 / R_MIPS_GPREL32 relocations use the following
expressions for calculations:
```
local symbol: S + A + GP0 - GP
global symbol: S + A - GP
GP - Represents the final gp value, i.e. _gp symbol
GP0 - Represents the gp value used to create the relocatable object
```
The GP0 value is taken from the .reginfo data section defined by an object
file. To implement that I keep a reference to `MipsReginfoInputSection`
in the `ObjectFile` class. This reference is used by the
`ObjectFile::getMipsGp0` method to return the GP0 value.
Differential Revision: http://reviews.llvm.org/D15760
llvm-svn: 256416
The file crtbeginT.o has relocations pointing to the start of an empty
.eh_frame that is known to be the first in the link. It does that to
identify the start of the output .eh_frame. Handle this special case.
Differential revision: http://reviews.llvm.org/D15610
llvm-svn: 256414
In FreeBSD, rtld expects .ctors containing -1 (0xffffffff), and a
.ctors section containing the correct bits is provided to the linker as
input (/usr/lib/crtbegin.o).
Contents of section .ctors:
0000 ffffffff ffffffff ........
This section is not stripped even if not referenced or empty, also in
gold or ld.bfd. It would be nice to strip it when not needed but
since existing object files rely on that we can't do better to keep it
around.
Differential Revision: http://reviews.llvm.org/D15767
llvm-svn: 256373
Before this patch sections that go after relro sequence were placed at
the same memory page with relro ones. It caused segmentation fault on
freebsd.
Fixes PR25790.
Patch by George Rimar with some tweaks by myself.
llvm-svn: 256334
The patch adds support for R_MIPS_PC16, R_MIPS_PC19_S2, R_MIPS_PC21_S2,
R_MIPS_PC26_S2, R_MIPS_PCHI16, R_MIPS_PCLO16 relocations handling.
llvm-svn: 256172
This patch changes sequence of applying relocations, moving tls optimized relocation handling code before code for other locals.
Without that change relocation @GOTTPOFF against local symbol caused runtime error ("unrecognized reloc ...").
That change also should fix other tls optimized relocations, but I did not check them, that's a field for another patch.
R_X86_64_GOTTPOFF relocations against locals can be found when linking against libc.a(malloc.o):
000000000036 000600000016 R_X86_64_GOTTPOFF 0000000000000000 libc_tsd_MALLOC - 4
000000000131 000600000016 R_X86_64_GOTTPOFF 0000000000000000 libc_tsd_MALLOC - 4
Differential revision: http://reviews.llvm.org/D15581
llvm-svn: 256145
This relocation is similar to R_*_RELATIVE except that the value used in this relocation is the program address returned by the function, which takes no arguments, at the address of
the result of the corresponding R_*_RELATIVE relocation as specified in the processor-specific ABI. The purpose of this relocation to avoid name lookup for locally defined STT_GNU_IFUNC symbols at load-time.
More info can be found in ifunc.txt from https://sites.google.com/site/x32abi/documents.
Differential revision: http://reviews.llvm.org/D15235
llvm-svn: 256144
R_386_GOTOFF is calculated as S + A - GOT, where:
S - Represents the value of the symbol whose index resides in the relocation entry.
A - Represents the addend used to compute the value of the relocatable field.
GOT - Represents the address of the global offset table.
Differential revision: http://reviews.llvm.org/D15383
llvm-svn: 256143
MIPS .reginfo section provides information on the registers used by
the code in the object file. Linker should collect this information and
write .reginfo section in the output file. This section contains a union
of used registers masks taken from input .reginfo sections and final
value of the `_gp` symbol.
For details see the "Register Information" section in Chapter 4 in the
following document:
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
The patch implements .reginfo sections handling with a couple missed
features: a) it does not put output .reginfo section into the separate
REGINFO segment; b) it does not merge `ri_cprmask` masks from input
section. These features will be implemented later.
Differential Revision: http://reviews.llvm.org/D15669
llvm-svn: 256119
The patch configure ELF header flags for MIPS target. For now the flags
are hard coded. In fact they depends on ELF flags of input object files
and selected emulation.
Differential Revision: http://reviews.llvm.org/D15575
llvm-svn: 256089
The assembly at the top of this file contained more relocations than
the YAML. I regenerated it so that we'd have complete relocation testing.
Also added detailed explanations of the relocations in the file so that
future people don't have to try decode them when something goes wrong.
llvm-svn: 256064
@indntpoff is similar to @gotntpoff, but for use in position dependent code. While @gotntpoff resolves to GOT slot address relative to the
start of the GOT in the movl or addl instructions, @indntpoff resolves to the
absolute GOT slot address. ("ELF Handling For Thread-Local Storage", Ulrich Drepper).
Differential revision: http://reviews.llvm.org/D15494
llvm-svn: 255884
negDelta32 is only ever implicitly generated as the FDE->CIE reference.
We therefore don't emit a relocation for it in the object file in -r mode.
The value we write in to the FDE location therefore needs to point to the
final target address of the CIE, and not the inAtomAddress as it was currently
doing.
llvm-svn: 255835
The `_gp_disp` is a magic symbol designates offset between start of
function and gp pointer into GOT. Only `R_MIPS_HI16` and `R_MIPS_LO16`
relocations are permitted with `_gp_disp`. The patch adds the `_gp_disp`
as an ignored symbol and adjusts symbol value before call the `relocateOne`
for `R_MIPS_HI16/LO16` relocations.
Differential Revision: http://reviews.llvm.org/D15480
llvm-svn: 255768
The `R_MIPS_JALR` is a relocation generated by gcc and gas. This
relocation points to the `jalr` instruction which might be optimized and
converted to the `b` instruction under some conditions.
Now we just ignore this relocation and keep instructions unchanged.
llvm-svn: 255453
If we don't filter these out we can end up, generating bogus paths, for example:
/home/user/lld/build/bin -> /home/user/home/user/lld/build/bin/lld/build/bin.
llvm-svn: 255378
It is reasonable to specify an entry point for shared objects - for
example, for the FreeBSD rtld ld-elf.so.1.
Unlike GNU ld we leave the entry address as 0 if -shared is specified
without -e.
Differential Revision: http://reviews.llvm.org/D15454
llvm-svn: 255349
R_X86_64_SIZE64/R_X86_64_SIZE32 relocations were introduced in 0.98v of "System V Application Binary Interface x86-64" (http://www.x86-64.org/documentation/abi.pdf).
Calculation for them is Z + A, where:
Z - Represents the size of the symbol whose index resides in the relocation entry.
A - Represents the addend used to compute the value of the relocatable field.
Differential revision: http://reviews.llvm.org/D15335
llvm-svn: 255332
When llvm-lit prints a failure, you'll see something like 'lld *command*' However, you can't then take this, paste it in to a terminal and run it, because it's not got the absolute path of lld.
llvm and clang's lit.cfg files contain lists of commands to look for which are substituted by their full paths. So now you'd see something like '*build dir*/bin/lld *command*'.
This patch adds the same capability to lld's lit.cfg
Reviewed by Rafael Espíndola
llvm-svn: 255283
The delta64 relocation is represented as the pair ARM64_RELOC_SUBTRACTOR and ARM64_RELOC_UNSIGNED.
Those should always have the same offset, so this adds a check and tests to ensure this is the case.
Also updated the error printing in this case to shows both relocs when erroring on pair.
llvm-svn: 255274
List all sections removed by garbage collection. This option is only effective if garbage collection has been enabled via the `--gc-sections' option.
Differential revision: http://reviews.llvm.org/D15327
llvm-svn: 255235
If R_386_PLT32 relocation is applied against symbol that can not be preempted then it can be resolved statically.
Patch implements it for x86 target.
Differential revision: http://reviews.llvm.org/D15376
llvm-svn: 255233
Implement the TLS relocation optimization for 32-bit x86 that is described in
"ELF Handling For Thread-Local Storage" by Ulrich Drepper, chapter 5,
"IA-32 Linker Optimizations". Specifically, this patch implements these
optimizations: LD->LE, GD->IE, GD->LD, and IE->LE.
Differential revision: http://reviews.llvm.org/D15292
llvm-svn: 255103
The gcc_except_tab was generating these references to point to the typeinfo in the data section.
gcc_except_tab also had the DW_EH_PE_indirect flag set which means that at runtime we are going
to dereference this entry as if it is in the GOT.
Reviewed by Nick Kledzik in http://reviews.llvm.org/D15360.
llvm-svn: 255085
All relocations, which cannot be handled by the dynamic linker,
cause a linking error "rebuild with -fPIC".
Differential revision: http://reviews.llvm.org/D15193
llvm-svn: 254840
"Ulrich Drepper, ELF Handling For Thread-Local Storage" (5.5 x86-x64 linker optimizations, http://www.akkadia.org/drepper/tls.pdf) shows how GD can be optimized to IE.
This patch implements the optimization.
Differential revision: http://reviews.llvm.org/D15000
llvm-svn: 254713
If a section symbol is not external, that COMDAT section should never
be merge with other sections in other compilation unit. Previously,
we didn't take visibility into account.
Note that COMDAT sections with non-external visibility makes sense
because they can be removed by dead-stripping.
Fixes https://llvm.org/bugs/show_bug.cgi?id=25686
llvm-svn: 254578
Main aim of the patch to introduce basic support for TLS access models for x86 target.
Models using @tlsgd, @tlsldm and @gotntpoff are implemented.
Differential revision: http://reviews.llvm.org/D15060
llvm-svn: 254500
Some MIPS relocations including `R_MIPS_HI16/R_MIPS_LO16` use combined
addends. Such addend is calculated using addends of both paired relocations.
Each `R_MIPS_HI16` relocation is paired with the next `R_MIPS_LO16`
relocation. ABI requires to compute such combined addend in case of REL
relocation record format only.
For details see p. 4-17 at
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
This patch implements lookup of the next paired relocation suing new
`InputSectionBase::findPairedRelocLocation` method. The primary
disadvantage of this approach is that we put MIPS specific logic into
the common code. The next disadvantage is that we lookup `R_MIPS_LO16`
for each `R_MIPS_HI16` relocation, while in fact multiple `R_MIPS_HI16`
might be paired with the single `R_MIPS_LO16`. From the other side
this way allows us to keep `MipsTargetInfo` class stateless and implement
later relocation handling in parallel.
This patch does not support `R_MIPS_HI16/R_MIPS_LO16` relocations against
`_gp_disp` symbol. In that case the relocations use a special formula for
the calculation. That will be implemented later.
Differential Revision: http://reviews.llvm.org/D15112
llvm-svn: 254461
Combination of @tlsgd and @gottpoff at the same time leads to miss of R_X86_64_TPOFF64 dynamic relocation. Patch fixes that.
@tlsgd(%rip) - Allocate two contiguous entries in the GOT to hold a tls index
structure (for passing to tls get addr).
@gottpoff(%rip) - Allocate one GOT entry to hold a variable offset in initial TLS
block (relative to TLS block end, %fs:0).
The same situation can be observed for x86 (probably others too, not sure) with corresponding for that target relocations: @tlsgd, @gotntpoff.
Differential revision: http://reviews.llvm.org/D15105
llvm-svn: 254443
ABI specifies the allowed range for these relocations as 2^(n-1) <= X < 2^n.
The patch fixes checks and introduces precise tests for these relocations.
Differential revision: http://reviews.llvm.org/D14957
llvm-svn: 254146
In case a sysroot prefix is configured, and the filename starts with
the '/' character, and the script being processed was located inside
the sysroot prefix, the file's name will be looked for in the sysroot
prefix. Otherwise, the linker falls to the common lookup scheme.
It is slightly modified version of the commit r254031. The problem of
the initial commit was in the `is_absolute` call. On Windows 'C:\' is
absolute path but we do not need to find it under sysroot. In this patch
linker looks up a path under sysroot only if the paths starts with '/'
character.
llvm-svn: 254135
Implements @tlsld (LD to LE) and @tlsgd (GD to LE) optimizations.
Patch does not implement the GD->IE case for @tlsgd.
Differential revision: http://reviews.llvm.org/D14870
llvm-svn: 254101
Patch implements lazy relocations for x86.
One of features of x86 is that executable files and shared object files have separate procedure linkage tables. So patch implements both cases.
Detailed information about instructions used can be found in http://docs.oracle.com/cd/E19620-01/805-3050/chapter6-1235/index.html (search: x86: Procedure Linkage Table).
Differential revision: http://reviews.llvm.org/D14955
llvm-svn: 254098
R_MIPS_CALL16 relocation provides the same result as R_MIPS_GOT16
relocation but does not need to check the result on overflow.
Differential Revision: http://reviews.llvm.org/D14916
llvm-svn: 254092
This patch implements next relocations:
R_386_TLS_LE - Negative offset relative to static TLS (GNU version).
R_386_TLS_LE_32 - Offset relative to static TLS block.
These ones are created when using next code sequences:
* @tpoff - The operator must be used to compute an immediate value. The linker will report
an error if the referenced variable is not defined or it is not code for the executable
itself. No GOT entry is created in this case.
* @ntpoff Calculate the negative offset of the variable it is added to relative to the static TLS block.
The operator must be used to compute an immediate value. The linker will report
an error if the referenced variable is not defined or it is not code for the executable
itself. No GOT entry is created in this case.
Information was found in Ulrich Drepper, ELF Handling For Thread-Local Storage, http://www.akkadia.org/drepper/tls.pdf, (6.2, p76)
Differential revision: http://reviews.llvm.org/D14930
llvm-svn: 254090
In the previous patch (r254003), I made the linker emit PT_GNU_STACK
unconditionally. But sometimes you want to have a control over the
presence of the segment. With this patch, you can omit the segment
by passing -z execstack option.
llvm-svn: 254039
In case a sysroot prefix is configured, and the filename starts with the
'/' character, and the script being processed was located inside the
sysroot prefix, the file's name will be looked for in the sysroot
prefix. Otherwise, the linker falls to the common lookup scheme.
https://www.sourceware.org/binutils/docs-2.24/ld/File-Commands.html
Differential Revision: http://reviews.llvm.org/D14916
llvm-svn: 254031
Partial (-z relro) and full (-z relro, -z now) relro cases are implemented.
Partial relro:
The ELF sections are reordered so that the ELF internal data sections (.got, .dtors, etc.) precede the program's data sections (.data and .bss).
.got is readonly, .got.plt is still writeable.
Full relro:
Supports all the features of partial RELRO, .got.plt is also readonly.
Differential revision: http://reviews.llvm.org/D14218
llvm-svn: 253967
R_X86_64_GOTTPOFF is not always requires GOT entries. Some relocations can be converted to local ones.
Differential revision: http://reviews.llvm.org/D14713
llvm-svn: 253966
With these relocations, it is now possible to build a simple "hello world"
program for AArch64 Debian.
Differential revision: http://reviews.llvm.org/D14917
llvm-svn: 253957
With this patch, lld creates PT_GNU_STACK segments only when all input
files have .note.GNU-stack sections. This is in line with other linkers
with a minor difference (we don't care about .note.GNU-stack rwx bits as
you can always remove .note.GNU-stack sections instead of setting x bit.)
At least, NetBSD loader does not understand PT_GNU_STACK segments and
reject any executables that have the section. This patch makes lld
compatible with such operating systems.
llvm-svn: 253797
This option is passed by clang driver if the target triple
is "aarch64-unknown-linux".
Differential Revision: http://reviews.llvm.org/D14831
llvm-svn: 253639
Rafael Espindola