Commit Graph

140 Commits

Author SHA1 Message Date
Rui Ueyama dfa577bafb Fix formatting.
llvm-svn: 253620
2015-11-19 23:30:10 +00:00
Igor Kudrin 351b41de4e [ELF2] Remove target specific code from GotPltSection.
The content of reserved entries of the .got.plt section is target specific.

In particular, on x86_64 the zero entry holds the address of the .dynamic section,
but on AArch64 the same info is stored in the zero entry of the .got section.

Differential revision: http://reviews.llvm.org/D14703

llvm-svn: 253239
2015-11-16 17:44:08 +00:00
George Rimar 687138c7d1 [ELF2] - Implemented R_X86_64_GOTTPOFF relocation
Generates single GOT entry, R_X86_64_TPOFF64 is added to RelaDyn.

Differential revision: http://reviews.llvm.org/D14621

llvm-svn: 253049
2015-11-13 16:28:53 +00:00
George Rimar 4b40ebce66 [ELF2] - fix of eh-frame-merge.s and eh-frame-merge.s tests fails for win32 configuration.
llvm-svn: 253043
2015-11-13 13:44:59 +00:00
Michael J. Spencer ecd7f377dd [elf2] get{Local,Global}DynamicReloc -> is{LocalGlobal}DynamicReloc.
llvm-svn: 252982
2015-11-13 00:32:58 +00:00
Michael J. Spencer 627ae703b5 [elf2] Implement global dynamic tls.
llvm-svn: 252979
2015-11-13 00:28:34 +00:00
Igor Kudrin 304860ab67 [ELF2] Add mandatory .dynamic section entries on MIPS.
The MIPS target requires specific dynamic section entries to be defined.

 * DT_MIPS_RLD_VERSION and DT_MIPS_FLAGS store predefined values.
 * DT_MIPS_BASE_ADDRESS holds base VA.
 * DT_MIPS_LOCAL_GOTNO holds the number of local GOT entries.
 * DT_MIPS_SYMTABNO holds the number of .dynsym entries.
 * DT_MIPS_GOTSYM holds the index of the .dynsym entry
   which corresponds to the first entry of the global part of GOT.
 * DT_MIPS_RLD_MAP holds the address of the reserved space in the data segment.
 * DT_MIPS_PLTGOT points to the .got.plt section if it exists.
 * DT_PLTGOT holds the address of the GOT section.

See "Dynamic Section" in Chapter 5 in the following document for detailed
description: ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf

Differential revision: http://reviews.llvm.org/D14450

llvm-svn: 252857
2015-11-12 04:39:49 +00:00
Igor Kudrin f4cdfe88ee [ELF2] Sort dynamic symbols according to the MIPS requirements.
The MIPS ABI has requirements to sort the entries in the .dyn.sym section.
Symbols which are not in the GOT have to precede the symbols which are added to
the GOT. The latter must have the same order as the corresponding GOT entries.

Since these sorting requirements contradict those of the GNU hash section,
they cannot be used together.

Differential revision: http://reviews.llvm.org/D14281

llvm-svn: 252854
2015-11-12 04:08:12 +00:00
Rafael Espindola 0c6a4f197f Add support for processing .eh_frame.
This adds support for:
* Uniquing CIEs
* Dropping FDEs that point to dropped sections

It drops 657 488 bytes from the .eh_frame of a Release+Asserts clang.

The link time impact is smallish. Linking clang with a Release+Asserts
lld goes from 0.488064805 seconds to 0.504763060 seconds (1.034 X slower).

llvm-svn: 252790
2015-11-11 19:54:14 +00:00
Michael J. Spencer dc9c5df5cd [elf2] Add support for local TLS symbols.
llvm-svn: 252686
2015-11-11 01:28:23 +00:00
Michael J. Spencer 1e22561a57 [elf2] Add support for R_X86_64_TLSLD.
leaq symbol@tlsld(%rip), %rdi
call __tls_get_addr@plt

symbol@tlsld (R_X86_64_TLSLD) instructs the linker to generate a tls_index entry (two GOT slots) in the GOT for the entire module (shared object or executable) with an offset of 0. The symbol for this GOT entry doesn't matter (as long as it's either local to the module or null), and gold doesn't put a symbol in the dynamic R_X86_64_DTPMOD64 relocation for the GOT entry.

All other platforms defined in http://www.akkadia.org/drepper/tls.pdf except for Itanium use a similar model where global and local dynamic GOT entries take up 2 contiguous GOT slots, so we can handle this in a unified manner if we don't care about Itanium.

While scanning relocations we need to identify local dynamic relocations and generate a single tls_index entry in the GOT for the module and store the address of it somewhere so we can later statically resolve the offset for R_X86_64_TLSLD relocations. We also need to generate a R_X86_64_DTPMOD64 relocation in the RelaDyn relocation section.

This implementation is a bit hacky. It side steps the issue of GotSection and RelocationSection only handling SymbolBody entries by relying on a specific relocation type. The alternative to this seemed to be completely rewriting how GotSection and RelocationSection work, or using a different hacky signaling method.

llvm-svn: 252682
2015-11-11 01:00:24 +00:00
Rafael Espindola 8ea46e00f1 Start treating .eh_frame specially.
For now, just don't follow edges leaving from it to mark other sections
live.

llvm-svn: 252493
2015-11-09 17:44:10 +00:00
Rafael Espindola ea7a1e9092 Round up the memsize of PT_TLS.
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
2015-11-06 22:14:44 +00:00
Igor Kudrin 15cd9ffd1e [ELF2] Add GOT section for MIPS target.
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
2015-11-06 07:43:03 +00:00
Michael J. Spencer d77f0d2526 [elf2] Implement R_X86_64_TPOFF32.
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
2015-11-03 22:39:09 +00:00
Rafael Espindola 9b89608698 Remove a redundant boolean.
llvm-svn: 251921
2015-11-03 14:34:11 +00:00
Rafael Espindola 31f8888cd9 Make a method static. NFC.
llvm-svn: 251799
2015-11-02 14:33:11 +00:00
Igor Kudrin 2169b1bd26 [ELF2] Ensure that .dynsym section is finalized before .gnu.hash.
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
2015-11-02 10:46:14 +00:00
George Rimar bc590feb2b [ELF2] R_X86_64_COPY relocation implemented
Differential revision: http://reviews.llvm.org/D14090.

llvm-svn: 251526
2015-10-28 16:48:58 +00:00
Igor Kudrin f1d6029016 [ELF2] Move sorting and data to the GNU hash table section.
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
2015-10-28 07:05:56 +00:00
George Rimar f940d5918f Another fix of -Wqual-const warning.
llvm-svn: 251259
2015-10-25 20:14:07 +00:00
Rafael Espindola f82ed2a28c Add support for merging string from SHF_STRINGS sections.
llvm-svn: 251212
2015-10-24 22:51:01 +00:00
Rui Ueyama 157c433a83 ELF2: Remove setNameOffset and combine that with writeHeader. NFC.
llvm-svn: 251193
2015-10-24 17:57:39 +00:00
Rui Ueyama 9fbb3d8850 ELF2: Rename StringTableSection::getFileOff -> getOffset.
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
2015-10-24 17:44:52 +00:00
Rafael Espindola 48225b4433 Drop a few const to reduce the noise from the next patch. NFC.
llvm-svn: 251140
2015-10-23 19:55:11 +00:00
Rui Ueyama c4aaed9255 ELF2: Implement --gc-sections.
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
2015-10-22 18:49:53 +00:00
Igor Kudrin 1b0d7066ff [ELF2] Add support for GNU Hash section
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
2015-10-22 08:21:35 +00:00
Rui Ueyama 8f2c4da65a ELF2: Rename getMostConstrainingVisibility -> getVisibility. NFC.
The previous name was too long.

llvm-svn: 250920
2015-10-21 18:13:47 +00:00
Rui Ueyama c96d0dd431 ELF2: Simplify DT_FLAGS{,_1} handling. NFC.
llvm-svn: 250914
2015-10-21 17:47:10 +00:00
Davide Italiano 6e91c598b9 [ELF2] Add support for -z origin.
llvm-svn: 250907
2015-10-21 17:09:47 +00:00
Rafael Espindola f5af835759 Fix symbol value calculation in SHF_MERGE.
We would get the wrong value if the symbol was in the middle of an entry.

llvm-svn: 250865
2015-10-20 22:08:49 +00:00
Igor Kudrin ab665fc475 [ELF2] Determine the order of entries of symbol tables in the finalize() phase.
* 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
2015-10-20 21:47:58 +00:00
Igor Kudrin 853b88d7ff [ELF2] Extract calculation of symbol binding as a separate function.
Differential Revision: http://reviews.llvm.org/D13910

llvm-svn: 250855
2015-10-20 20:52:14 +00:00
George Rimar 0f5ac9f571 [ELF2] .shstrtab section implemented
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
2015-10-20 17:21:35 +00:00
George Rimar 648a2c37fb [ELF2] - Lazy relocation support for x86_64.
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
2015-10-20 08:54:27 +00:00
Davide Italiano 06edc7c0aa [ELF2] Correctly set bits when -z now is specified.
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
2015-10-20 04:58:40 +00:00
Davide Italiano 88f476b9eb [ELF2] Introduce support for -z nodelete.
llvm-svn: 250771
2015-10-20 00:20:20 +00:00
Davide Italiano 58cbaf0604 [ELF2/OutputSections] Allocate the correct number of entries after r250739.
llvm-svn: 250760
2015-10-19 23:32:16 +00:00
Davide Italiano 56d18f4f8a [OutputSection] Set the symbolic bit in DT_FLAGS and not DT_FLAGS_1.
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
2015-10-19 21:34:00 +00:00
Rafael Espindola c159c967f6 Add support for merging the contents of SHF_MERGE sections.
For now SHF_STRINGS are not supported.

llvm-svn: 250737
2015-10-19 21:00:02 +00:00
Rui Ueyama b7f2867a85 Reduce nesting level. NFC.
llvm-svn: 250732
2015-10-19 20:31:49 +00:00
Rafael Espindola 932efcfa77 Change getLocalRelTarget to include the addend.
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
2015-10-19 20:24:44 +00:00
Rafael Espindola 4975752389 Simplify by computing on relocation field at a time.
llvm-svn: 250730
2015-10-19 19:58:18 +00:00
Igor Kudrin ea6a835f4e [ELF2] In/out parameter of writeGlobalSymbols() is changed to in parameter.
There is no outer code which requires the changed value.

llvm-svn: 250688
2015-10-19 08:01:51 +00:00
Rafael Espindola 80c94a7856 Use a reference. NFC.
llvm-svn: 250578
2015-10-16 23:22:23 +00:00
Rui Ueyama 6455852a28 ELF2: Treat IsMips64EL as a global configuration.
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
2015-10-16 22:51:43 +00:00
Hal Finkel 230c5c5b52 [ELF2] Remove unneeded new Type parameter
As pointed out by Rafael (with a further suggestion by Rui), the new Type
parameter I added in r250555 is not needed. Remove it.

llvm-svn: 250563
2015-10-16 22:37:32 +00:00
Hal Finkel c91740616a [ELF2] Don't create RelativeReloc for weak undef symbols
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
2015-10-16 22:11:05 +00:00
Hal Finkel 6f97c2bc00 [ELF2] getLocalRelTarget should handle R_PPC64_TOC directly
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
2015-10-16 21:55:40 +00:00
Rafael Espindola 4cda58168a Add a ObjectFile<ELFT>::getSection helper and simplify. NFC.
llvm-svn: 250519
2015-10-16 15:29:48 +00:00