This is cleaner than computing relocations as if we had done it.
While at it, keep a single Phdr variable instead of multiple fields of it.
llvm-svn: 252352
This patch implements R_MIPS_GOT16 relocation for global symbols in order to
generate some entries in GOT. Only reserved and global entries are supported
for now. For the detailed description about GOT in MIPS, see "Global Offset
Table" in Chapter 5 in the followin document:
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
In addition, the platform specific symbol "_gp" is added, see "Global Data
Symbols" in Chapter 6 in the aforementioned document.
Differential revision: http://reviews.llvm.org/D14211
llvm-svn: 252275
This does not support TPOFF32 relocations to local symbols as the address calculations are separate. Support for this will be a separate patch.
llvm-svn: 251998
It is required to fill up the GNU hash table section before its
finalize() method is called.
Differential Revision: http://reviews.llvm.org/D14196
llvm-svn: 251789
It is the GNU hash table section that should be reaponsible for storing its own
data and applying its requirements for the order to dynamic symbols.
Differential Revision: http://reviews.llvm.org/D14084
llvm-svn: 251502
getFileOff functions defined for other classes return an offset
from beginning of the file. StringTableSection's getFileOff however
returned an offset from beginning of the section. That was confusing.
llvm-svn: 251192
Section garbage collection is a feature to remove unused sections
from outputs. Unused sections are sections that cannot be reachable
from known GC-root symbols or sections. Naturally the feature is
implemented as a mark-sweep garbage collector.
In this patch, I added Live bit to InputSectionBase. If and only
if Live bit is on, the section will be written to the output.
Starting from GC-root symbols or sections, a new function, markLive(),
visits all reachable sections and sets their Live bits. Writer then
ignores sections whose Live bit is off, so that such sections are
excluded from the output.
This change has small negative impact on performance if you use
the feature because making sections means more work. The time to
link Clang changes from 0.356s to 0.386s, or +8%.
It reduces Clang size from 57,764,984 bytes to 55,296,600 bytes.
That is 4.3% reduction.
http://reviews.llvm.org/D13950
llvm-svn: 251043
This patch implements --hash-style command line switch.
* By default, or with "sysv" or "both" parameters, the linker generates
a standard ELF hash section.
* With "gnu" or "both", it produces a GNU-style hash section.
That section requires the symbols in the dynamic symbol table section, which
are referenced in the GNU hash section, to be placed after not hashed ones and
to be sorted to correspond the order of hash buckets in the GNU Hash section.
The division function, as well as estimations for the section's parameters,
are just the first rough attempt and the subjects for further adjustments.
Differential Revision: http://reviews.llvm.org/D13815
llvm-svn: 251000
* Move the responsibility to call SymbolBody::setDynamicSymbolTableIndex()
from the hash table to the dynamic symbol table.
* Hash table is not longer responsible for filling the dynamic symbol table.
* The final order of symbols of both symbol tables is set before writing
phase starts.
* Remove repeaded scan of the symbol table during writting SymbolTableSection.
Differential Revision: http://reviews.llvm.org/D13911
llvm-svn: 250864
The section header table index of the entry that is associated with the section name string table.
Differential Revision: http://reviews.llvm.org/D13904
llvm-svn: 250836
Target has supportsLazyRelocations() method which can switch lazy relocations on/off (currently all targets are OFF except x64 which is ON). So no any other targets are affected now.
Differential Revision: http://reviews.llvm.org/D13856?id=37726
llvm-svn: 250808
The option now just sets NOW bit in DT_FLAGS_1 but some loaders
seem to require also BIND_NOW bit to be set in DT_FLAGS. This is,
also, what ld.bfd and gold do.
Differential Revision: http://reviews.llvm.org/D13883
llvm-svn: 250799
The two names are similar enough that they might lead to confusion.
The output of readobj clarifies but I missed it when I originally
committed this. Found while linking FreeBSD userland with lld.
llvm-svn: 250739
Given the name, it is natural for this function to compute the full target.
This will simplify SHF_MERGE handling by allowing getLocalRelTarget to
centralize the addend logic.
llvm-svn: 250731
If one file is MIPS64EL, all files are MIPS64EL, and vice versa.
We do not have to look up MIPS-ness for each file. Currently we
do not support 64-bit MIPS, so the config value is always false.
llvm-svn: 250566
When we have a R_PPC64_ADDR64 for a weak undef symbol, which thus resolves to
0, and we're creating a shared library, we need to make sure that it stays 0
(because code that conditionally calls the weak function tests for this).
Unfortunately, we were creating a R_PPC64_RELATIVE for these relocation
targets, making the address of the undefined weak symbol equal to the base
address of the shared library (which is non-zero). In general, we should not be
creating RelativeReloc relocs for undef weak symbols.
llvm-svn: 250558
R_PPC64_TOC does not have an associated symbol, but does have a non-zero VA
that target-specific code must compute using some non-trivial rule. We
handled this as a special case in PPC64TargetInfo::relocateOne, where
we knew to write this special address, but that did not work when creating shared
libraries. The special TOC address needs to be the subject of a
R_PPC64_RELATIVE relocation, and so we also need to know how to encode this
special address in the addend of that relocation.
Thus, some target-specific logic is necessary when creating R_PPC64_RELATIVE as
well. To solve this problem, we teach getLocalRelTarget to handle R_PPC64_TOC
as a special case. This allows us to remove the special case in
PPC64TargetInfo::relocateOne (simplifying code there), and naturally allows the
existing logic to do the right thing when creating associated R_PPC64_RELATIVE
relocations for shared libraries.
llvm-svn: 250555
This patch is to use ELFT instead of Is64Bits to template OutputSection
and its subclasses. This increases code size slightly because it creates
two identical functions for some classes, but that's only 20 KB out of
33 MB, so it's negligible.
This is as per discussion with Rafael. He's not fan of the idea but OK
with this. We'll revisit later to this topic.
llvm-svn: 250466
What was done:
1) .got.plt section is created for functions that requires PLT. .got.plt has 3 predefined empty entries now that are required for dynamic linker.
Also other new items created are configured to have correct jump to PLT[N].
2) PLT section now has PLT[0] entry, also others ones are configured to support PLT->GOT(.got.plt) calls.
3) Implemented .rel[a].plt sections (based on patch http://reviews.llvm.org/D13569).
4) Fixed plt relocations types (based on patch http://reviews.llvm.org/D13589).
NOTES:
The .plt.got zero entry is still empty now. According to ELF specification it should hold the address of the dynamic structure, referenced with the symbol
_DYNAMIC. The _DYNAMIC entry points to the .dynamic section which contains information used by the ELF interpreter to setup the binary.
Differential Revision: http://reviews.llvm.org/D13651
llvm-svn: 250169
This patch adds AsNeeded and IsUsed bool fields to SharedFile. AsNeeded bit
is set if the DSO is enclosed with --as-needed and --no-as-needed. IsUsed
bit is off by default. When we adds a symbol to the symbol table for dynamic
linking, we set its SharedFile's IsUsed bit.
If AsNeeded is set but IsUsed is not set, we don't want to write that
file's SO name to DT_NEEDED field.
http://reviews.llvm.org/D13579
llvm-svn: 249998
SymbolTable was not a template class. Instead we had switch-case-based
type dispatch to call desired functions. We had to do that because
SymbolTable was created before we know what ELF type objects had been
passed.
Every time I tried to add a new function to the symbol table, I had to
define a dispatcher which consist of a single switch statement.
It also brought an restriction what the driver can do. For example,
we cannot add undefined symbols before any files are added to the symbol
table. That's because no symbols can be added until the symbol table
knows the ELF type, but when it knows about that, it's too late.
In this patch, the driver makes a decision on what ELF type objects
are being handled. Then the driver creates a SymbolTable object for
an appropriate ELF type.
http://reviews.llvm.org/D13544
llvm-svn: 249902
This reverts commit r249816.
It broke building llvm with lld:
$ ./bin/FileCheck
./bin/FileCheck: error while loading shared libraries: unexpected PLT reloc type 0x06
I think the only thing that is wrong with this patch is that it is too soon.
The plt we create (and its relocs) don't support lazy loading, so they have
to be relocated as ordinary dynamic relocations.
llvm-svn: 249835
.rela.plt contains list of elements in the PLT, which are liable to the relocation during the dynamic linking.
Differential Revision: http://reviews.llvm.org/D13569
llvm-svn: 249816
The size of a .plt entry is different on different targets (it is,
specifically, much larger than 8 on all PPC ABIs). There is no functional
change here (later patches to create .plt entries for PPC64 will depend on this
change).
llvm-svn: 249756
In preparation for making the size of a .plt entry target dependent, use the
existing EntrySize variable when writing (instead of a hard-coded value). NFC.
llvm-svn: 249720
Previously, output sections that are handled specially by the linker
(e.g. PLT or GOT) were created by Writer and passed to other classes
that need them. The problem was that because these special sections
are required by so many classes, the plumbing work became too much
burden.
This patch is to simply make them accessible from anywhere in the
linker to eliminate the plumbing work once and for all.
http://reviews.llvm.org/D13486
llvm-svn: 249590
When generating an executable or shared library, mark it to tell the dynamic linker to resolve all symbols when the program is started, or when the shared library is linked to using dlopen, instead of deferring function call resolution to the point when the function is first called.
Differential Revision: http://reviews.llvm.org/D13468
llvm-svn: 249551
This is a case that requires --start-group --end-group with regular ELF
linkers. Fortunately it is still possible to handle it with lazy symbols without
taking a second look at archives.
Thanks to Michael Spencer for the bug report.
llvm-svn: 249406
The entries are added if there are "_init" or "_fini" entries in
the symbol table respectively. According to the behavior of ld,
entries are inserted even for undefined symbols.
Symbol names can be overridden by using -init and -fini command
line switches. If used, these switches neither add new symbol table
entries nor require those symbols to be resolved.
Differential Revision: http://reviews.llvm.org/D13385
llvm-svn: 249297
Using the "raw" Elf64_Dyn or Elf32_Dyn structures in
DynamicSection<ELFT>::writeTo does not correctly handle mixed-Endian
situations. Instead, use the corresponding llvm::object::* structures which
have Endian-converting members (like the rest of the code).
This fixes all currently-failing elf2 tests when running on big-Endian
PPC64/Linux (I've added a big-Endian test case which should fail on
little-Endian machines in the same way that test/elf2/shared.s failed on
big-Endian machines prior to this change).
llvm-svn: 249150
Sort by:
ALLOC
ALLOC && NOBITS
ALLOC & EXEC
ALLOC & EXEC && NOBITS
ALLOC & WRITE
ALLOC & WRITE && NOBITS
<nothing> (ignoring NOBITS)
The dynamic section is finalized early because it adds strings to the dynamic string table, which comes before the dynamic table.
llvm-svn: 249071
If a shared library has a DT_SONAME entry, that is what should be included
in the DT_NEEDED of a program using it.
We don't implement -soname yet, so check in a .so for now.
llvm-svn: 249025
Sort by:
ALLOC
ALLOC && NOBITS
ALLOC & EXEC
ALLOC & EXEC && NOBITS
ALLOC & WRITE
ALLOC & WRITE && NOBITS
<nothing> (ignoring NOBITS)
The dynamic section is finalized early because it adds strings to the dynamic string table, which comes before the dynamic table.
llvm-svn: 248845
Unfortunately the i386 and x86_64 relocation have the same numerical value
and it is a probably a bit much to add got support for another architecture
just to test this.
llvm-svn: 248326
This is just enough to get PLT working on 32 bit x86.
The idea behind using a virtual interface is that it should be easy to
convert any of the functions to template parameters if any turns out to be
performance critical.
llvm-svn: 248308
Rafael Espindola