Currently LLD calls the `isMicroMips` routine to determine type of PLT entries
needs to be generated: regular or microMIPS. This routine checks ELF
header flags in the `FirstObj` to retrieve type of linked object files.
So if the first file does not contain microMIPS code, LLD will generate
PLT entries with regular (non-microMIPS) code only.
Ideally, if a PLT entry is referenced by microMIPS code only this entry
should contain microMIPS code, if a PLT entry is referenced by regular
code this entry should contain regular code. In a "mixed" case the PLT
entry can be either microMIPS or regular, but each "cross-mode-call" has
additional cost.
It's rather difficult to implement this ideal solution. But we can
assume that if there is an input object file with microMIPS code, the
most part of the code is microMIPS too. So we need to deduce type of PLT
entries based on finally calculated ELF header flags and do not check
only the first input object file.
This change implements this.
- The `getMipsEFlags` renamed to the `calcMipsEFlags`. The function
called from the `LinkerDriver::link`. Result is stored in
the Configuration::MipsEFlags field.
- The `isMicroMips` and `isMipsR6` routines access the `MipsEFlags`
field to get and check calculated ELF flags.
- New types of PLT records created when necessary.
Differential revision: https://reviews.llvm.org/D37747
llvm-svn: 314675
This fixes pr34301.
As the bug points out, we want to keep some relocations with undefined
weak symbols. This means that we cannot always claim that these
symbols are not preemptible as we do now.
Unfortunately, we cannot also just always claim that they are
preemptible. Doing so would, for example, cause us to try to create a
plt entry when we don't even have a dynamic symbol table.
What almost works is to say that weak undefined symbols are
preemptible if and only if we have a dynamic symbol table. Almost
because we don't want to fail the build trying to create a copy
relocation to a weak undefined.
llvm-svn: 313372
This allows combining --dynamic-list and version scripts too. The
version script controls which symbols are visible, and
--dynamic-list controls which of those are preemptible.
Unlike previous versions, undefined symbols are still considered
preemptible, which was the issue breaking the cfi tests.
This fixes pr34053.
llvm-svn: 312806
If --dynamic-list is given, only those symbols are preemptible.
This allows combining --dynamic-list and version scripts too. The
version script controls which symbols are visible, and --dynamic-list
controls which of those are preemptible.
This fixes pr34053.
llvm-svn: 312757
Patch by Rafael Espíndola.
This is PR34053.
The implementation is a bit of a hack, given the precise location where
IsPreemtible is set, it cannot be used from
SymbolTable::handleAnonymousVersion.
I could add another method to SymbolTable if you think that would be
better.
Differential Revision: https://reviews.llvm.org/D36499
llvm-svn: 311468
Previously we handled this option implicitly, only
for infering unresolved symbols handling policy.
ld man says: "--noinhibit-exec Retain the executable
output file whenever it is still usable",
and we may want to handle other cases too.
Differential revision: https://reviews.llvm.org/D35793
llvm-svn: 309091
Summary:
If the linker is invoked with `--chroot /foo` and `/bar/baz.o`, it
tries to read the file from `/foo/bar/baz.o`. This feature is useful
when you are dealing with files created by the --reproduce option.
Reviewers: grimar
Subscribers: llvm-commits, emaste
Differential Revision: https://reviews.llvm.org/D35517
llvm-svn: 308646
This is PR33766.
-F name
--filter=name
When creating an ELF shared object, set the internal DT_FILTER field to the specified name. This tells the dynamic linker that the symbol table of the shared object which is being created should be used as a filter on the symbol table of the shared object name.
If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the DT_FILTER field. The dynamic linker will resolve symbols according to the symbol table of the filter object as usual, but it will actually link to the definitions found in the shared object name. Thus the filter object can be used to select a subset of the symbols provided by the object name.
(https://linux.die.net/man/1/ld).
Shared Objects as Filters:
https://docs.oracle.com/cd/E19683-01/817-3677/chapter4-31738/index.html
Differential revision: https://reviews.llvm.org/D35352
llvm-svn: 308167
Previously, when symbol A is renamed B, both A and B end up having
the same name. This is because name is a symbol's attribute, and
we memcpy symbols for symbol renaming.
This pathc saves the original symbol name and restore it after memcpy
to keep the original name.
This patch shouldn't change program's meaning, but names in symbol
tables make more sense than before.
llvm-svn: 306036
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
procedural optimizations to prevent dropping symbols and allow the linker
to process re-directs.
PR33145: --wrap doesn't work with lto.
Differential Revision: https://reviews.llvm.org/D33621
llvm-svn: 304719
The .dynamic section of an ELF almost doesn't need to be written to with
the exception of the DT_DEBUG entry. For several reasons having a read
only .dynamic section would be useful. This change adds the -z keyword
"rodynamic" which forces .dynamic to be read-only. In this case DT_DEBUG
will not be emited.
Patch by Jake Ehrlich
Differential Revision: https://reviews.llvm.org/D33251
llvm-svn: 304024
This reverts changes introduced in r302414 "[ELF] - Set DF_STATIC_TLS flag for i386 target."
Because DF_STATIC_TLS does not look to be used by glibc or anything else.
llvm-svn: 302884
This is PR32437.
DF_STATIC_TLS
If set in a shared object or executable, this flag instructs the
dynamic linker to reject attempts to load this file dynamically.
It indicates that the shared object or executable contains code
using a static thread-local storage scheme. Implementations need
not support any form of thread-local storage.
Patch checks if IE/LE relocations were used to check if code uses
static model. If so it sets the DF_STATIC_TLS flag.
Differential revision: https://reviews.llvm.org/D32354
llvm-svn: 302414
It seems virtually everyone who tries to do LTO build with Clang and
LLD was hit by a mistake to forget using llvm-ar command to create
archive files. I wasn't an exception. Since this is an annoying common
issue, it is probably better to handle that gracefully rather than
reporting an error and tell the user to redo build with different
configuration.
Differential Revision: https://reviews.llvm.org/D32721
llvm-svn: 302083
For an option -foo-bar-baz, we have Config->FooBarBaz. Since -rpath is
-rpath and not -r-path, it should be Config->Rpath instead Config->RPath.
llvm-svn: 301759
Patch implements --compress-debug-sections=zlib.
In compare with D20211 (a year old patch, abandoned), it implementation
uses streaming and fully reimplemented, does not support zlib-gnu for
simplification.
This is PR32308.
Differential revision: https://reviews.llvm.org/D31941
llvm-svn: 300444
This is a shorthand for Config->Wordsize == 8. So this is not strictly
necessary but seems handy. "Is 64 bit?" is easier to read than "Is
wordsize 8 byte?"
llvm-svn: 298463
We had a few Config member functions that returns configuration values.
For example, we had is64() which returns true if the target is 64-bit.
The return values of these functions are constant and never change.
This patch is to compute them only once to make it clear that they'll
never change.
llvm-svn: 298168
Summary:
When we perform LTO builds with a version of ar that does not
understand LLVM bitcode objects, we end up with undefined references,
because our archive files do not list the bitcode symbols in their
indices. The error messages do not make it clear what the real problem
is. This change adds a note that points out the likely problem and
solution. It is similar in spirit to r282633, but aims to avoid false
positives by only triggering when we see both undefined references and
archives without symbols in their indices.
Fixes PR32281.
Reviewers: davide, ruiu, tejohnson
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31011
llvm-svn: 298124
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
Patch introduces Config->is64Bit() and with help of that detemplates
GotPltSection and IgotPltSection sections
Differential revision: https://reviews.llvm.org/D30944
llvm-svn: 297813
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
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
with temporarily file name fix in testcase.
Original commit message:
-q, --emit-relocs - Generate relocations in output
Simplest implementation:
* no GC case,
* no "/DISCARD/" linkerscript command support.
This patch is extracted from D28612 / D29636,
Relative to PR31579.
Differential revision: https://reviews.llvm.org/D29663
llvm-svn: 294469
-q, --emit-relocs - Generate relocations in output
Simplest implementation:
* no GC case,
* no "/DISCARD/" linkerscript command support.
This patch is extracted from D28612 / D29636,
Relative to PR31579.
Differential revision: https://reviews.llvm.org/D29663
llvm-svn: 294464
Now reportUndefined only has to look at Config->UnresolvedSymbols and
the symbol. getUnresolvedSymbolOption does all the hard work of
mapping options like -shared and -z defs to one of the
UnresolvedPolicy enum entries.
The critical fix is that now "-z defs --warn-unresolved-symbols" only
warns.
llvm-svn: 293290
It now uses the same infrastructure as symbol versions. This fixes us
creating a dynamic relocation without a corresponding dynamic symbol.
This also means that unlike gold and bfd we keep a STB_LOCAL in the
static symbol table. It seems an odd feature to offer precise control
over what is in a symbol table that is not used by the dynamic
linker. We can bring this back if needed, but it would probably be
better to just have --discard option that tells the linker to keep in
the static symbol table only what is in the dynamic one.
Should fix the eog build.
llvm-svn: 293093
Currently ld.lld -r allocates space for common symbols, whereas ld.bfd
-r doesn't. As a result the OpenBSD makefile bits for creating libraries
fail as they use ld -X -r to strip local symbols, which results in
duplicate symbol errors because space for the common symbols has been
allocated.
The diff also implements the --define-commons option such that allocation
of commons can be forced even if -r is used.
Patch by Mark Kettenis.
llvm-svn: 292878
That variable was of type DenseMap<StringRef, unsigned>, but the
unsigned numbers needed to be monotonicly increasing numbers because
the implementation that used the variable depended on that fact.
That was an implementation detail and shouldn't have leaked into Config.
This patch simplifies its type to std::vector<StringRef>.
llvm-svn: 290151
--retain-symbols-file=filename
Retain only the symbols listed in the file filename, discarding all others.
filename is simply a flat file, with one symbol name per line. This option
is especially useful in environments (such as VxWorks) where a large global
symbol table is accumulated gradually, to conserve run-time memory.
Note: though documentation says "--retain-symbols-file does not discard
undefined symbols, or symbols needed for relocations.", both bfd and gold
do that, and this patch too, like testcase show.
Differential revision: https://reviews.llvm.org/D27716
llvm-svn: 290122
Use of CachedHashStringRef makes sense only when we reuse hash values.
Sprinkling it to all DenseMap has no benefits and just complicates data types.
Basically we shouldn't use CachedHashStringRef unless there is a strong
reason to to do so.
llvm-svn: 290076
The feature is documented as
-----------------------------
The format of the dynamic list is the same as the version node
without scope and node name. See *note VERSION:: for more
information.
--------------------------------
And indeed qt uses a dynamic list with an 'extern "C++"' in it. With
this patch we support that
The change to gc-sections-shared makes us match bfd. Just because we
kept bar doesn't mean it has to be in the dynamic symbol table.
The changes to invalid-dynamic-list.test and reproduce.s are because
of the new parser.
The changes to version-script.s are the only case where we change
behavior with regards to bfd, but I would like to see a mix of
--version-script and --dynamic-list used in the wild before
complicating the code.
llvm-svn: 289082
Shared libraries should have entry set following the same rules as for
regular binaries. The only difference is that in case the default entry
point (_start or __start) isn't found (unless it was set explicitly), we
shouldn't give a warning as in case of regular binaries.
Differential Revision: https://reviews.llvm.org/D27497
llvm-svn: 288878
-N (-omagic)
Set the text and data sections to be readable and writable.
Also, do not page-align the data segment.
Differential revision: https://reviews.llvm.org/D26888
llvm-svn: 288123
--no-rosegment: Do not put read-only non-executable sections in their own segment
Differential revision: https://reviews.llvm.org/D26889
llvm-svn: 288020
-color-diagnostics=auto is default because that's the same as
Clang's default. When color is enabled, error or warning messages
are colored like this.
error:
<bold>ld.lld</bold> <red>error:</red> foo.o: no such file
warning:
<bold>ld.lld</bold> <magenta>warning:</magenta> foo.o: no such file
Differential Revision: https://reviews.llvm.org/D27117
llvm-svn: 287949
This is in the context of https://llvm.org/bugs/show_bug.cgi?id=31109.
When LLD prints out errors for relocations, it tends to print out
extremely large number of errors (like millions) because it would
print out one error per relocation.
This patch makes LLD bail out if it prints out more than 20 errors.
You can configure the limitation using -error-limit argument.
-error-limit=0 means no limit.
I chose the flag name because Clang has the same feature as -ferror-limit.
"f" doesn't make sense to us, so I omitted it.
Differential Revision: https://reviews.llvm.org/D26981
llvm-svn: 287789
This change separates all versioned locals to be a separate list in config,
that was suggested by Rafael and simplifies the logic a bit.
Differential revision: https://reviews.llvm.org/D26754
llvm-svn: 287132
Previously we did not support anything except "local: *", patch changes that.
Actually GNU rules of proccessing wildcards are more complex than that (http://www.airs.com/blog/archives/300):
There are 2 iteration for wildcards, at first iteration "*" wildcards are ignored and handled at second iteration.
Since we previously decided not to implement such complex rules,
I suggest solution that is implemented in this patch. So for "local: *" case nothing changes,
but if we have wildcarded locals,
they are processed before wildcarded globals.
This should fix several FreeBSD ports, one of them is jpeg-turbo-1.5.1 and
currently blocks about 5k of ports.
Differential revision: https://reviews.llvm.org/D26395
llvm-svn: 286713
Patch allows to pass a symbols file to linker.
LLD will map symbols to sections and sort sections
in output according to symbol ordering file.
That can help to reduce the startup time and/or
amount of pagefaults during startup.
Also, interesting benchmark result was produced by Rafael Espíndola.
After applying the symbols file for clang he timed compiling
X86MCTargetDesc.ii to an object file.
The page faults went from just
56,988 to 56,946 since most faults are not in the binary.
Running time went from 4.403053515 to 4.178112244.
The speedup seems to be because of better cache
locality.
Differential revision: https://reviews.llvm.org/D26130
llvm-svn: 286440
In short the patch introduces support for linking object file conform
MIPS N32 ABI [1]. This ABI is similar to N64 ABI but uses 32-bit
pointer size.
The most non-trivial requirement of this ABI is one more relocation
packing format. N64 ABI puts multiple relocation type into the single
relocation record. The N32 ABI uses series of successive relocations
with the same offset for this purpose. In this patch, new function
`mergeMipsN32RelTypes` handle this case and "convert" N32 relocation to
the N64 relocation so the rest of the code keep unchanged.
For now, linker does not support series of relocations applied to sections
without SHF_ALLOC bit. Probably later I will add the support or insert
some sort of assert into the `relocateNonAlloc` routine to catch this
case.
[1] ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/MIPS-N32-ABI-Handbook.pdf
Differential revision: https://reviews.llvm.org/D26298
llvm-svn: 286052
As the state of lld gets more complicated, shutting down gets more
expensive.
In a normal lld run we can just call _exit immediately after renaming
the temporary output file. We still want the ability to run a full
shutdown since that is useful for detecting memory leaks.
This patch adds a --full-shutdown flag and changes lit to use it.
llvm-svn: 285224
In this patch partial gdb_index section is created.
For costructing the .gdb_index section 6 steps should be performed (details are in
SplitDebugInfo.cpp file header), this patch do first 3:
Creates proper section header.
Fills list of compilation units.
Types CU list area is not supposed to be supported, so it is ignored and therefore
can be treated as implemented either.
Differential revision: https://reviews.llvm.org/D24706
llvm-svn: 284708
Previously, we were checking the existence of an entry symbol
too early. It was done before the linker script processor creates
symbols defined in scripts. Fixes bug 30743.
llvm-svn: 284676
The R_ARM_TARGET2 relocation is used in ARM exception tables to encode
a data dependency that will only be dereferenced by code in the
run-time support library. In a similar way to R_ARM_TARGET1 the
handling of the relocation is target specific, it maps to one of
R_ARM_ABS32, R_ARM_REL32 or R_ARM_GOT_PREL. The choice depends on the
run-time library. R_ARM_GOT_PREL is used for linux and BSD,
R_ARM_ABS32 and R_ARM_REL32 are used for bare-metal.
The command line option --target2=<target> can be used to select the
relocation used for R_ARM_TARGET2. The default is R_ARM_GOT_PREL.
Differential revision: https://reviews.llvm.org/D25684
llvm-svn: 284404
-z wxneeded creates a PHDR PT_OPENBSD_WXNEEDED.
PT_OPENBSD_WXNEEDED
The array element specifies that a process executing this file may need to be able to map or protect memory regions as simultaneously executable and writable. If the system is unable or unwilling to permit that for this executable then it may fail immediately. This segment type is meaningful only for executable files and is ignored in other objects.
http://man.openbsd.org/OpenBSD-current/man5/elf.5
Differential revision: https://reviews.llvm.org/D25472
llvm-svn: 284226
--section-start=sectionname=org
Locate a section in the output file at the absolute address given by org.
You may use this option as many times as necessary to locate multiple sections in the command line.
org must be a single hexadecimal integer; for compatibility with other linkers,
you may omit the leading `0x' usually associated with hexadecimal values.
Note: there should be no white space between sectionname, the equals sign (“<=>”), and org.
-Tbss=org
-Tdata=org
-Ttext=org
Same as --section-start, with .bss, .data or .text as the sectionname.
Differential revision: https://reviews.llvm.org/D24294
llvm-svn: 281458
Implemented by building an ELF file in memory.
elf, default, and binary match gold behavior.
Differential Revision: https://reviews.llvm.org/D24060
llvm-svn: 281108
Fixed code that was not checked before on windows for me, because of testcases that are
disabled on that platform atm.
Inital commit message:
"[ELF] - Versionscript: do not treat non-wildcarded names as wildcards."
Previously we incorrectly handled cases when symbol name in extern c++ tag
was enclosed in quotes. Next case was treated as wildcard:
GLIBCXX_3.4 {
extern "C++" {
"aaa*"
}
But it should have not. Quotes around aaa here means that we should have do exact
name matching.
That is PR30268 which has name with pointer is interpreted as wildcard by lld:
extern "C++" {
"operator delete[](void*)";
Patch fixes the issue.
Differential revision: https://reviews.llvm.org/D24229
llvm-svn: 281049
Fixed code that was not checked by testcases that are disabled on windows.
Inital commit message:
"[ELF] - Versionscript: do not treat non-wildcarded names as wildcards."
Previously we incorrectly handled cases when symbol name in extern c++ tag
was enclosed in quotes. Next case was treated as wildcard:
GLIBCXX_3.4 {
extern "C++" {
"aaa*"
}
But it should have not. Quotes around aaa here means that we should have do exact
name matching.
That is PR30268 which has name with pointer is interpreted as wildcard by lld:
extern "C++" {
"operator delete[](void*)";
Patch fixes the issue.
Differential revision: https://reviews.llvm.org/D24229
llvm-svn: 281045
Previously we incorrectly handled cases when symbol name in extern c++ tag
was enclosed in quotes. Next case was treated as wildcard:
GLIBCXX_3.4 {
extern "C++" {
"aaa*"
}
But it should have not. Quotes around aaa here means that we should have do exact
name matching.
That is PR30268 which has name with pointer is interpreted as wildcard by lld:
extern "C++" {
"operator delete[](void*)";
Patch fixes the issue.
Differential revision: https://reviews.llvm.org/D24229
llvm-svn: 281038
"Error" looks like it is indicating a parse error. "Error" actually
instructs the later process to report an error if there's an error
condition. Thus the new name.
llvm-svn: 280529
FreeBSD's libstdc++ build (used on tier-2 architectures) uses GNU ld's
-f <name> option, which sets the DT_AUXILIARY field to the specified name.
Multiple -f options may be specified and the DT_AUXILIARY entries
will be added in the order in which they appear.
Patch implements that option.
Differential revision: https://reviews.llvm.org/D24139
llvm-svn: 280475
DiscardPolicy is enum replacing several boolean options.
This approach is not only consistent with what we use for
unresolveds (UnresolvedPolicy), but also should help to solve a problem
of options with opposing meanings, mentioned in PR28843
Differential revision: https://reviews.llvm.org/D23868
llvm-svn: 280209
This approach is not only consistent with UnresolvedPolicy,
but also should help to solve a problem
of options with opposing meanings, mentioned in PR28843
Differential revision: https://reviews.llvm.org/D23869
llvm-svn: 280206
Rafael Espindola