The /appcontainer flag indicates that the module may only be used inside
an application container (for isolation). This has been supported by
link.exe since Windows 8.0. It sets an additional bit in the PE DLL
Characteristics flag to indicate the behavioural change.
llvm-svn: 299728
Executable sections should not be padded with zero by default. On some
architectures, 0x00 is the start of a valid instruction sequence, so can confuse
disassembly between InputSections (and indeed the start of the next InputSection
in some situations). Further, in the case of misjumps into padding, padding may
start to be executed silently.
On x86, the "0xcc" byte represents the int3 trap instruction. It is a single
byte long so can serve well as padding. This change switches x86 (and x86_64) to
use this value for padding in executable sections, if no linker script directive
overrides it. It also puts the behaviour into place making it easy to change the
behaviour of other targets when desired. I do not know the relevant instruction
sequences for trap instructions on other targets however, so somebody should add
this separately.
Because the old behaviour simply wrote padding in the whole section before
overwriting most of it, this change also modifies the padding algorithm to write
padding only where needed. This in turn has caused a small behaviour change with
regards to what values are written via Fill commands in linker scripts, bringing
it into line with ld.bfd. The fill value is now written starting from the end of
the previous block, which means that it always starts from the first byte of the
fill, whereas the old behaviour meant that the padding sometimes started mid-way
through the fill value. See the test changes for more details.
Reviewed by: ruiu
Differential Revision: https://reviews.llvm.org/D30886
Bugzilla: http://bugs.llvm.org/show_bug.cgi?id=32227
llvm-svn: 299635
Previously, the code we set to our .plt entries expected that .got
and .got.plt are consecutive in the virtual address space.
Since %ebx points to the last entry of .got for position-independent
code, it assumed that .got is accessible with small negative
displacements and .got.plt are accessible with small positive
displacements.
That assumption was simply wrong. We don't impose any restrictions on
relative layout of .got and .got.plt. As a result, the control is
transferred to a bogus address from .plt at runtime, which resulted in
segfaults.
This patch removes that wrong assumption. We still assume that .got.plt
has a fixed relative address to .got, but we no longer assume that they
are consecutive in memory.
With this change, a "hello world" program compiled with -fPIC works.
Fixes https://bugs.llvm.org/show_bug.cgi?id=31332.
Differential Revision: https://reviews.llvm.org/D31682
llvm-svn: 299553
GNU linkers define __bss_start symbol.
Patch teaches LLD to do that. This is PR32051.
Below is part of standart ld.bfd script:
.data1 : { *(.data1) }
_edata = .; PROVIDE (edata = .);
. = .;
__bss_start = .;
.bss :
{
Currently LLD can emit up to 3 .bss* sections as one of testcase shows.
Implementation inserts this symbol before first .bss* output section.
Differential revision: https://reviews.llvm.org/D30419
llvm-svn: 299528
Summary:
This adds support for reporting multiple errors in a single invocation of lld-link. The limit defaults to 20 and can be changed with the /ERRORLIMIT command line parameter, or set to unlimited by passing a value of 0.
This is a new attempt after r295507, which was reverted because opening files raced with exiting early, causing the test to be flaky. This version avoids the race by exiting before calling enqueuePath.
Reviewers: pcc, ruiu
Reviewed By: ruiu
Subscribers: llvm-commits, dblaikie
Differential Revision: https://reviews.llvm.org/D31688
llvm-svn: 299496
The ELF spec says:
all of the non-default visibility attributes, when applied to a symbol
reference, imply that a definition to satisfy that reference must be
provided within the current executable or shared object.
But we were trying to resolve those undef references to shared
symbols. That causes odd results like creating a got entry with
a relocation pointing to 0.
llvm-svn: 299464
As with the changes made in r297645, we do not want a potentially long link to
be run, if it will ultimately fail because the map file is not writable. This
change reuses the same functionality as the output file path check. See
https://reviews.llvm.org/D30449 for further justification and explanations.
Reviewers: ruiu
Differential Revision: https://reviews.llvm.org/D31603
llvm-svn: 299420
The existing names for the ARM and Thumb Thunks highlight their current
use as interworking Thunks. These Thunks can also be used for range
extension Thunks where there is no state change. This change makes the name
more generic so it is suitable for range extension.
Differential Revision: https://reviews.llvm.org/D31605
llvm-svn: 299418
Previous error message style:
error: /home/alice/src/bar.c:12: relocation R_X86_64_PLT32 cannot refer to absolute symbol 'answer' defined in /home/alice/src/foo.o
New error message style:
error: relocation R_X86_64_PLT32 cannot refer to absolute symbol: foo
>>> defined in /home/alice/src/foo.o
>>> referenced by bar.c:12 (/home/alice/src/bar.c:12)
>>> /home/alice/src/bar.o:(.text+0x1)
llvm-svn: 299390
This patch is intended to improve readability of "duplicate symbol"
error messages.
Without this patch:
/ssd/clang/bin/ld.lld: error: /ssd/llvm-project/lld/ELF/Relocations.cpp:1054: duplicate symbol 'lld:🧝:demangle(llvm::StringRef)'
/ssd/clang/bin/ld.lld: error: /ssd/llvm-project/lld/ELF/Strings.cpp:93: previous definition was here
With this patch:
/ssd/clang/bin/ld.lld: error: duplicate symbol: lld:🧝:demangle(llvm::StringRef)
>>> defined at Strings.cpp:93 (/ssd/llvm-project/lld/ELF/Strings.cpp:93)
>>> Strings.cpp.o:(lld:🧝:demangle(llvm::StringRef)) in archive lib/liblldELF.a
>>> defined at Relocations.cpp:1054 (/ssd/llvm-project/lld/ELF/Relocations.cpp:1054)
>>> Relocations.cpp.o:(.text+0x4C30) in archive lib/liblldELF.a
Discussion thread:
http://lists.llvm.org/pipermail/llvm-dev/2017-March/111459.html
Differential Revision: https://reviews.llvm.org/D31507
llvm-svn: 299280
This is a test change applicable for ARM targets.
Previously LLVM would generate a mapping symbol when code contains only
data. This was changed as part of
https://reviews.llvm.org/D30724
and to be more close to the ARM ELF ABI.
The test case is changed to check for behavior with minimal changes.
Patch by Shankar Easwaran
Differential Revision: https://reviews.llvm.org/D31500
llvm-svn: 299212
Previously, undefined symbol errors are one line like this
and wasn't easy to read.
/ssd/clang/bin/ld.lld: error: /ssd/llvm-project/lld/ELF/Writer.cpp:207: undefined symbol 'lld:🧝:EhFrameSection<llvm::object::ELFType<(llvm::support::endianness)0, true> >::addSection(lld:🧝:InputSectionBase*)'
This patch make it more structured like this.
bin/ld.lld: error: undefined symbol: lld:🧝:EhFrameSection<llvm::object::ELFType<(llvm::support::endianness)0, true>
>>> Referenced by Writer.cpp:207 (/ssd/llvm-project/lld/ELF/Writer.cpp:207)
>>> Writer.cpp.o in archive lib/liblldELF.a
Discussion thread:
http://lists.llvm.org/pipermail/llvm-dev/2017-March/111459.html
Differential Revision: https://reviews.llvm.org/D31481
llvm-svn: 299097
Summary: In the ELF linker, we create the buffer identifier for bitcode files by appending the object name to the archive name. This change makes the COFF linker do the same. Without the change, ThinLTO builds can fail with an error message about multiple ThinLTO modules per object file, caused by object files contained in different archives having the same name.
Reviewers: pcc, ruiu
Reviewed By: pcc
Subscribers: mehdi_amini
Differential Revision: https://reviews.llvm.org/D31402
llvm-svn: 298942
.gnu.hash happen to contain only 32-bit integers for 32-bit arch,
but the section contents are not uniform array members, so setting
entsize doesn't make much sense. This behavior seems to have been
blindly copied from GNU linkers.
llvm-svn: 298934
Summary: MSVC does this when producing a PDB.
Reviewers: ruiu
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31316
llvm-svn: 298717
This requires collectign all symbols referenced in the linker script
and adding them to symbol table as undefined symbol.
Differential Revision: https://reviews.llvm.org/D31147
llvm-svn: 298577
This is to improve compatibility with GNU Libtool that expect
/supported targets:.* elf/ in a message for the -help option.
Differential Revision: https://reviews.llvm.org/D31208
llvm-svn: 298568
This will be used in the sanitizer test suite, which wants to use DWARF
line tables.
At some point we should reconsider how LLD handles the long section
names required by DWARF debug sections.
llvm-svn: 298544
Summary:
This also delays setting the output filename based on the first input
argument until after processing /def.
Fixes PR32354
Reviewers: ruiu, pcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31152
llvm-svn: 298327
The patch introduces two new relocations expressions R_MIPS_GOT_GP and
R_MIPS_GOT_GP_PC. The first one represents a current value of `_gp`
pointer and used to calculate relocations against the `__gnu_local_gp`
symbol. The second one represents the offset between the beginning of
the function and the `_gp` pointer's value.
There are two motivations for introducing new expressions:
- It's better to keep all non-trivial relocation calculations in the
single place - `getRelocTargetVA` function.
- Relocations against both `_gp_disp` and `__gnu_local_gp` symbols
depend on the `_gp` value. It's a magical value points to the "middle"
of GOT. Now all relocations use a common `_gp` value. But in fact,
under some conditions each input file might require its own `_gp`
value. I'm going to implement it in the future patches. So it's
better to make `MipsGotSection` responsible for calculation of
the `_gp` value.
llvm-svn: 298306
This is a safeguard against data loss if the user specifies a directory
that is not a cache directory. Teach the existing cache pruning clients
to create files with appropriate names.
Differential Revision: https://reviews.llvm.org/D31109
llvm-svn: 298271
__start_xxx symbol keeps section xxx alive only if it is not
SHF_LINK_ORDER. Such sections can be used for user metadata, when
__start_xxx is used to iterate over section contents at runtime, and
the liveness is determined solely by the linked (associated) section.
This was earlier implemented in r294592, and broken in r296723.
Differential Revision: https://reviews.llvm.org/D30964
llvm-svn: 298154
Do not take in account the `Live` flag while collecting .reginfo, .MIPS.options,
and .MIPS.abiflags input sections to produce corresponding output sections.
These sections have information purpose and should be always produced per
ABI requirements.
llvm-svn: 298093
This fixes pr32031 by representing the expressions results as a
SectionBase and offset. This allows us to use an input section
directly instead of getting lost trying to compute an offset in an
outputsection when not all the information is available yet.
This also creates a struct to represent the *value* of and expression,
allowing the expression itself to be a simple typedef. I think this is
easier to read and will make it easier to extend the expression
computation to handle more complicated cases.
llvm-svn: 298079
It failed for me under windows,
touch reported invalid date format.
Seems related to 12h/24h format, though
I don't understant why 197001010200 does not work,
but 197001010300 works, I see no logic here.
Changed to 197001011200.
llvm-svn: 298064
Was fixed, details on review page.
Original commit message:
That removes CopyRelSection class completely, making
Bss/BssRelRo to be just regular synthetics.
This is splitted from D30541 and polished.
Difference from D30541 that all logic of SharedSymbol
converting to DefinedRegular was removed for now and
probably will be posted as separate patch.
Differential revision: https://reviews.llvm.org/D30892
llvm-svn: 298062
Patch to fix lld tests after my llvm-objdump patch to fix branch labels for
Thumb targets.
Reviewed by: emaste
Differential Revision: https://reviews.llvm.org/D30986
llvm-svn: 298055
This patch causes us to use pruneCache() to prune the ThinLTO cache after
completing LTO. A new flag --thinlto-cache-policy allows users to configure
the policy.
Differential Revision: https://reviews.llvm.org/D31021
llvm-svn: 298036
The MSVC linker doesn't like archive files containing non-native object
files.
When we are doing an LTO build, we may create archive files containing
both LLVM bitcode files and native object files. For example, if a
project contains assembly files and C++ files, we create native object
files for the assembly files and LLVM bitcode files for the C++ files.
With the /msvclto option, LLD passes archive files to the MSVC linker.
Previously, we didn't pass archive files if they contain at least one
bitcode files. That wasn't correct because the native object files that
weren't passed to the MSVC linker may be needed to complete linking.
In this patch, we create new temporary archive files to strip bitcode
files.
Differential Revision: https://reviews.llvm.org/D31053
llvm-svn: 297997
This test would have been broken if we convert SharedSymbols
to DefinerRegular without saving the symbol version information when
creating .bss/.bss.rel.ro sections for copy relocations.
Relative to D30541, PR32167
llvm-svn: 297948
D30229 changes the defaults based on section names to match the
GAS behavior, which breaks some of the tests that rely on the old
defaults.
Differential Revision: https://reviews.llvm.org/D30967
llvm-svn: 297803
This also requires postponing the assignment the assignment of
symbols defined in input linker scripts since those can refer to
output sections and in case we don't have a SECTIONS command, we
need to wait until all output sections have been created and
assigned addresses.
Differential Revision: https://reviews.llvm.org/D30851
llvm-svn: 297802
Being passed -z notext is a pretty strong indication that the user is
OK with text relocations. This is not the same behavior as bfd, but
bfd defaults to -z notext, so it has to try to avoid text relocations
and use them as a last resort.
llvm-svn: 297789
lld crashes when .eh_frame or .eh_frame_hdr section is discarded
in linker script and there is no PHDRS directive.
Differential revision: https://reviews.llvm.org/D30885
llvm-svn: 297712
Synthetic sections don't belong to any input file, but still they
are input sections. Whenever problem occurs with relocations in
these sections lld crashes in error reporting, trying to print
input file name.
Differential revision: https://reviews.llvm.org/D30889
llvm-svn: 297711
Previously, it created a temporary directory and then failed when
FileOutputBuffer tried to rename that file to the destination file
(which is actually a directory name).
Differential Revision: https://reviews.llvm.org/D30912
llvm-svn: 297679
Patch from James Henderson.
If a user has a long link, e.g. due to a large LTO link, they do not
wish to run it and find that it failed because there was a mistake in
their command-line, after they waited for some significant amount of
time. This change adds some basic checking of the linker output file
path, which is run shortly after parsing the command-line and linker
script. An error is emitted if LLD cannot write to the specified path.
Differential Revision: https://reviews.llvm.org/D30449
llvm-svn: 297645
Fix a bug introduced in r297313 which caused them to resolve to the end
of the ELF header in PIEs and DSOs.
Differential Revision: https://reviews.llvm.org/D30843
llvm-svn: 297638
Options can start with `-` or `--` unless they start with "o".
Any option that starts with `-o` should be interpreted as an output
file name. This is a quote from the GNU ld man page.
Note -- there is one exception to this rule. Multiple letter
options that start with a lower case 'o' can only be preceded by
two dashes. This is to reduce confusion with the -o option.
So for example -omagic sets the output file name to magic whereas
--omagic sets the NMAGIC flag on the output.
We didn't handle that properly before.
llvm-svn: 297508
Using .eh_frame input section pattern in linker script currently
causes a crash; this is because .eh_frame input sections require
special handling since they're all combined into a synthetic
section rather than regular output section.
Differential Revision: https://reviews.llvm.org/D30627
llvm-svn: 297501
gold linker manual describes them as:
-z text Do not permit relocations in read-only segments
-z notext Permit relocations in read-only segments (default)
In LLD default is to not permit them. Patch implements -z notext.
Differential revision: https://reviews.llvm.org/D30530
llvm-svn: 297366
.eh_frame_hdr is a header constructed for .eh_frame sections.
We do not proccess .eh_frame when doing relocatable output,
so should not try to create .eh_frame_hdr too.
Previous behavior without this patch is segfault.
Fixes PR32118.
Differential revision: https://reviews.llvm.org/D30566
llvm-svn: 297365
Previously, if you have foo=bar in a definition file, this assertion
could fire because when symbols are read from file they could be mangled.
It seems that due to historical reasons underscore mangling scheme is
really ad-hoc, and I cannot find a clean way to handle this. I had
to just de-mangle symbols to search again.
llvm-svn: 297357
Some archive files created during chromium build contains both BC
and native files. If that's the case, we want to pass the archive
file to link.exe. Otherwise, the MSVC linker would complain that
there's an unresolved symbol in a given set of files.
I cannot explain why link.exe doesn't complain about the presence
of bitcode files in this case, but it seems link.exe doesn't touch BC.
llvm-svn: 297229
If /msvclto is specified, we compile bitcode files and pass it to the
MSVC linker, stripping all bitcode files. We haven't stripped archive
files, because I was thinking that the MSVC linker wouldn't touch files
in archive files. When we pass an object file to link.exe, all symbols
have been resolved already, so link.exe shoulnd't need any of the files
in archives.
It turns out that even though link.exe doesn't need to do that, it
seems to try to read each file in all archives. And if there's a non-
COFF file in an archive, it exists with an error message. So we need
to remove archives from the command line too.
llvm-svn: 297191
This change fixes a bug in which the Mips LA25 Thunks are always assigned
to the same Output section as the caller and not the callee as expected.
Differential Revision: https://reviews.llvm.org/D30637
llvm-svn: 297135
This puts us at parity with bfd, which could already gc this case.
I noticed the sections not being gced when linking a modified freebsd
kernel. A section that was not gced and not mentioned in the linker
script would end up breaking the expected layout. Since fixing the gc
is relatively simple and an improvement, that seems better than trying
to hack the orphan placement code.
There are 173 input section in the entire link whose names are valid C
identifiers, so this is probably not too performance critical.
llvm-svn: 297049
We were not gcing any section whose name was a C identifier. Both gold
and bfd only keep those if they are used.
To avoid having to create the __start/__stop symbols early or doing
string lookups in resolvedReloc, this patch just looks for undefined
symbols __start/__stop to decide if a section is needed or not.
llvm-svn: 296723
This patch adds an option named --thinlto-cache-dir, which specifies the
path to a directory in which to cache native object files for ThinLTO
incremental builds.
Differential Revision: https://reviews.llvm.org/D30509
llvm-svn: 296702
Previously, LLD merged all read-only sections. So the following
program prints out "true" if -icf=all is specified.
static const int foo = 1;
static const int bar = 1;
int main() { printf("%s\n", &foo == &bar ? "true" : "false"); }
This is somewhat counter-intuitive, and it actually caused nasty issues.
One example is https://bugs.chromium.org/p/chromium/issues/detail?id=682773#c24.
This patch changes the way how it works. Now ICF merges only functions
(i.e. executable sections).
Differential Revision: https://reviews.llvm.org/D30365
llvm-svn: 296534
I do not fully understand why we had these values in the tests, but
the new value matches what ld.bfd and ld.gold set, so I guess that
was just a mistake.
Differential Revision: https://reviews.llvm.org/D30441
llvm-svn: 296505
This reverts commit r296378.
I am pretty sure this is incorrect. In particular, for just
.cfi_startproc
nop
.cfi_endproc
We now add an extra 4 zeros that neither bfd nor gold add.
llvm-svn: 296503
Patch by Mark Kettenis.
Currenlty ld.lld does not add a terminator (a CIE with its length field
set to zero) to the .eh_frame sections it generates. While the relevant
standards (the AMD64 SysV ABI and the Linux LSB) are not explicit about
this, such a terminator is expected by some unwinder implementations and
seems to be always emitted by ld.bfd. In addition to that, the Linux LSB
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME
explicitly says that
The .eh_frame section shall contain 1 or more Call Frame Information
(CFI) records.
Currently, if the .eh_frame sections of the input files only contain
terminators, ld.lld emits a zero=sized .eh_frame section
which clearly doesn't meet that requirement.
The diff makes sure a terminator gets added to each .eh_frame section
and adjusts all the relevant tests to account for that. An additional
test isn't needed as these adjustments mean that the existence of the
terminator is tested for by several tests already.
Differential Revision: https://reviews.llvm.org/D30335
llvm-svn: 296378
__ehdr_start should be pointing to ELF file headers, not program
headers.
This is a reland of D30319.
Differential Revision: https://reviews.llvm.org/D30323
llvm-svn: 296085
Summary: Creates bitcode files suitable for use with ThinLTO, then checks that the linker can build an executable from them.
Reviewers: ruiu, pcc
Reviewed By: pcc
Subscribers: mehdi_amini, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D30277
llvm-svn: 296042
With this we complete the transition out of special output sections,
and with the previous patches it should be possible to merge
OutputSectionBase and OuputSection.
llvm-svn: 296023
For functions the linker uses a related hack: creating a plt in the
main executable that preempts the function.
Like bfd and gold, we don't disable it with nocopyreloc.
llvm-svn: 295976
We shouldn't report an error for R_*_NONE relocs since we're emitting
them when writing relocations to discarded sections.
Differential Revision: https://reviews.llvm.org/D30279
llvm-svn: 295936
I really do not understand what is going on on some Windows buildbots,
but FileCheck command on some buildbot behaves like long lines were
truncated. I'll try to find a cause of the issue, but let me relax the
test so that they'll succeed on all buildbots.
llvm-svn: 295798
Saleem Abdulrasool