Commit Graph

904 Commits

Author SHA1 Message Date
Eugene Leviant 3967ea05a9 Set entry address to 0x0 if no _start symbol
Differential revision: https://reviews.llvm.org/D23925

llvm-svn: 280912
2016-09-08 08:57:51 +00:00
Simon Atanasyan d9ea656021 [ELF][MIPS] Do not create a hidden definition for __tls_get_addr on MIPS
On most architectures the linker is required to optimize away any
references to __tls_get_addr in case of static linking. As usual
a special case is MIPS - libc defines __tls_get_addr itself because
there are no TLS optimizations for this architecture.

llvm-svn: 280664
2016-09-05 15:42:29 +00:00
Petr Hosek fdfcb796e1 [ELF] Do not omit debug sections when computing build-id
The primary use of build-id is in debugging, hence omitting debug
sections when computing it significantly reduces its usability as
changes in debug section content wouldn't alter the build-id.

Differential Revision: https://reviews.llvm.org/D24120

llvm-svn: 280421
2016-09-01 22:43:03 +00:00
Petr Hosek e5d3ca5031 [ELF] Linkerscript: define symbols outside SECTIONS
Symbol assignments outside of SECTIONS command need to be created
even when SECTIONS command is not used.

Differential Revision: https://reviews.llvm.org/D23751

llvm-svn: 280252
2016-08-31 15:31:17 +00:00
Rafael Espindola e7553e4eac Delete unnecessary template.
llvm-svn: 280237
2016-08-31 13:28:33 +00:00
George Rimar 9503f6d211 [ELF] - Introduce DiscardPolicy instead of 3 relative bool fields.
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
2016-08-31 08:46:30 +00:00
George Rimar f21aade0d8 [ELF] - Introduce StripPolicy instead of Config->StripAll/StripDebug flags.
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
2016-08-31 08:38:11 +00:00
Eugene Leviant e4f590faeb Allow .eh_frame_hdr to be placed before .eh_frame
Differential revision: https://reviews.llvm.org/D24041

llvm-svn: 280203
2016-08-31 07:43:50 +00:00
Eugene Leviant 933dae7435 Implement support for --build-id=uuid switch
Differential revision: https://reviews.llvm.org/D23349

llvm-svn: 279810
2016-08-26 09:55:37 +00:00
George Rimar 86ce267a4a [ELF] - Implemented --oformat binary option.
-oformat output-format
`-oformat' option can be used to specify the binary format for the output object file.

Patch implements binary format output type.

Differential revision: https://reviews.llvm.org/D23769

llvm-svn: 279726
2016-08-25 09:05:47 +00:00
Peter Smith a52864a78c Canonicalize output section name for .ARM.exidx sections
The ARM Exception handling ABI requires that all ARM exception index
table sections have a prefix of .ARM.exidx and are combined into a
single contiguous block either in their own output section or as part
of another output section.
    
In general clang will output a single .ARM.exidx section per object,
but will use .ARM.exidx.<section name> when -ffunction-sections is used.
    
This change canonicalizes the names of sections with the .ARM.exidx
prefix to just .ARM.exidx, which ensures that there is only a single
output section.

Differential Revision: https://reviews.llvm.org/D23775

llvm-svn: 279617
2016-08-24 09:08:54 +00:00
Petr Hosek 4f7a5c3bb4 [ELF] Define __ehdr_start symbol
This symbol can be used by the program to examine its own headers.

Differential Revision: https://reviews.llvm.org/D23750

llvm-svn: 279452
2016-08-22 18:44:04 +00:00
Rui Ueyama 189b871a62 Format.
llvm-svn: 279415
2016-08-22 04:55:41 +00:00
George Rimar e1937bb524 [ELF] - Give automatically generated __start_* and __stop_* symbols default visibility.
This patch is opposite to D19024, which made this symbols to be hidden by default.

Unfortunately FreeBSD loader wants to see
start_set_modmetadata_set/stop_set_modmetadata_set in the dynamic symbol table. 
They were not placed there because had hidden visibility.

Patch makes them to have default visibility again.

Differential revision: https://reviews.llvm.org/D23552

llvm-svn: 279262
2016-08-19 15:36:32 +00:00
Petr Hosek 1fb2ecc903 [ELF] Allow specifying the stack size
This option can be used to specify the stack size of the
PT_GNU_STACK segment.

Differential Revision: https://reviews.llvm.org/D23538

llvm-svn: 279013
2016-08-17 23:59:58 +00:00
George Rimar 8ceadb38a8 [ELF] - linkerscript AT keyword (in output section description) implemented.
The linker will normally set the LMA equal to the VMA. 
You can change that by using the AT keyword.
The expression lma that follows the AT keyword specifies 
the load address of the section.

Patch implements this keyword.

Differential revision: https://reviews.llvm.org/D19272

llvm-svn: 278911
2016-08-17 07:44:19 +00:00
Eugene Leviant f9bc3bd2cf [ELF] Ignore .interp section in case linker script specifies PHDRS without PT_INTERP
llvm-svn: 278781
2016-08-16 06:40:58 +00:00
Eugene Leviant a5c8a68535 [ELF] Do not add start and end symbols in case they are already defined
llvm-svn: 278657
2016-08-15 07:24:20 +00:00
Rui Ueyama bdf836db1b Simplify output section ownership management.
One reason why we are (ab)using OutputSectionFactory class is
because it owns output sections. Technically there's no need
to have it own sections. So, this patch transfers the ownership
to Out<ELFT>.

llvm-svn: 278452
2016-08-12 01:10:17 +00:00
Eugene Leviant ceabe80e97 [ELF] Symbol assignment within output section description
llvm-svn: 278322
2016-08-11 07:56:43 +00:00
Rui Ueyama 1034c9e342 Remove isOutputDynamic and use Out<ELFT>::DynSymTab instead.
This patch is to not instantiate DynSymTab and DynStrTab if the
output is not a dynamic output.

llvm-svn: 278095
2016-08-09 04:42:01 +00:00
Rui Ueyama cbd434a6c4 Remove redundant variable.
llvm-svn: 278094
2016-08-09 04:31:21 +00:00
Rui Ueyama a8f6feaa1a Separate {Preinit,Init,Fini}Arrays from Out<ELFT>::Dynamic.
Even if an output is not a dynamic object, the output may have
.{preinit,init,fini} sections. Therefore, managing these sections
as Out<ELFT>::Dynamic's members is not correct.

llvm-svn: 278093
2016-08-09 04:25:20 +00:00
Rui Ueyama 84907c5143 Do not pass the SymbolTable to writeResult.
The SymbolTable is always accessible as Symtab<ELFT>::X,
so no need to pass it as an argument.

llvm-svn: 278091
2016-08-09 03:38:23 +00:00
Rui Ueyama 210ef7fbd4 Remove redundant local variable.
llvm-svn: 278085
2016-08-09 01:35:39 +00:00
Rui Ueyama 30634d9b4f Reduce dependency to OutputSectionFactory.
The Factory class is too object-oriented-ish and easy to be abused.
This patch reduces dependency to that class. Eventually we want to
remove the dependency to that class from LinkerScript.

llvm-svn: 278084
2016-08-09 01:35:38 +00:00
Rui Ueyama 75118259ba Do not initialize Out<ELFT>::Opd until needed.
This change makes it clear that we need the variable only within
writeSections.

llvm-svn: 278083
2016-08-09 01:35:37 +00:00
Rui Ueyama 31f32fa62a Refactor getMipsEFlags.
Previously, we incrementally updated the reuslting flag as we check
file flags, so it was not very clear who is updating what flags.
This patch makes them pure functions -- that has no side effect and
don't update arguments to improve readability.

Now each function construct a patial result, and all resutls are then
bitwise-OR'ed to construct the final result.

This patch also creates a new file, Mips.cpp, to move all these
MIPS functions to a separate file.

Differential Revision: https://reviews.llvm.org/D23249

llvm-svn: 278042
2016-08-08 19:39:45 +00:00
George Rimar 28ac19c9ee [ELF] - Linkerscript: do not define _edata,_end,_etext if SECTIONS is used.
I faced that when tried to link FreeBSD kernel. 
It was "duplicate symbol: _edata in (internal) and (internal)" error.
_data was a shared symbol that came from hack.so. At first it was replaced with DefinedRegular by the code
disabled in this patch and later when script tried to define the same symbol - the error was shown.

In the same situation (as given in testcase) ld defines them as UND. gold defines as ABS with zero value. 
Patch just disables any operations of creating these symbols if script do layout.

Differential revision: https://reviews.llvm.org/D23206

llvm-svn: 277986
2016-08-08 08:42:48 +00:00
Simon Atanasyan 24c24fedba [ELF][MIPS] Produce a correct and complete set of MIPS ELF header flags
The patch extends the `getMipsEFlags` function. Now in that function
we iterate over all object files, parse ELF header flags and merge them.
If a file is incompatible with previously analyzed ones we show an error
or warning. That can happen if, for example, we try to link files with
incompatible ABI, ISA, NAN encoding etc.

There is an alternative solution. We can check and merge flags and
reject incompatible input modules in the `isCompatible` function which
is called from the `SymbolTable::addFile` method. But in that case we
have to save and keep somewhere a merged ELF flags combination to use it
later in the writer.

Differential Revision: http://reviews.llvm.org/D23161

llvm-svn: 277911
2016-08-06 05:11:41 +00:00
Rafael Espindola a4b41dca31 Remove redundant argument.
But always set Script<ELFT>::X->OutputSections.

llvm-svn: 277720
2016-08-04 12:13:05 +00:00
Nico Weber 2e36772caf Revert 277594, it caused PR28827
llvm-svn: 277599
2016-08-03 14:37:57 +00:00
Rafael Espindola a348532ec3 Remove redundant argument.
llvm-svn: 277594
2016-08-03 13:21:16 +00:00
Rafael Espindola 716a94787c Don't crash if PT_TLS is empty.
llvm-svn: 277202
2016-07-29 19:24:27 +00:00
George Rimar 9e69450ec7 [ELF] - Linkerscript: implemented SIZEOF(section)
SIZEOF(section)
Return the size in bytes of the named section, if that section has been allocated.

SIZEOF(section) often used in scripts. Few examples from the wild:
https://github.com/chipKIT32/pic32-Arduino-USB-Bootloader-original/blob/master/boot-linkerscript.ld
https://github.com/devkitPro/buildscripts/blob/master/dkarm-eabi/crtls/gba_cart.ld

Patch implements it.

Differential revision: https://reviews.llvm.org/D22915

llvm-svn: 277165
2016-07-29 16:18:47 +00:00
Rui Ueyama 09d4f177fc Remove dependency to SymbolTable from CommonInputSection.
llvm-svn: 277103
2016-07-29 03:39:44 +00:00
Rui Ueyama 3de0a3308b Rename DoLayout -> HasContents. NFC.
llvm-svn: 277102
2016-07-29 03:31:09 +00:00
Rui Ueyama ad10c3d8d4 Make CommonInputSection singleton class.
All other singleton instances are accessible globally.
CommonInputSection shouldn't be an exception.

Differential Revision: https://reviews.llvm.org/D22935

llvm-svn: 277034
2016-07-28 21:05:04 +00:00
Eugene Leviant 3e6b027705 [ELF] Allows setting section for common symbols in linker script
llvm-svn: 277023
2016-07-28 19:24:13 +00:00
Rafael Espindola 0b113671c5 Make toPhdrFlags a member function. NFC.
llvm-svn: 276868
2016-07-27 14:10:56 +00:00
Simon Atanasyan 240bc16532 [ELF][MIPS] Do not emit .got section in case of relocatable output
llvm-svn: 276808
2016-07-26 21:11:30 +00:00
Rui Ueyama 1b59f27c9a Add `static` to a function that is used only in one file.
llvm-svn: 276774
2016-07-26 17:35:42 +00:00
Rui Ueyama 96bdd5bc81 Do not pass InputFile to reportDiscarded().
Because the file from which an input section is created can be
obtained using getFile().

llvm-svn: 276702
2016-07-25 22:26:28 +00:00
George Rimar eea3114ff9 [ELF] - Linkerscript: add InputSectionDescription command to LS parser.
This adds InputSectionDescription command to represent
the input section declaration.

This leads to next cleanup:
SectionRule removed.
ScriptConfiguration::Sections mamber removed.
LinkerScript<ELFT>::getOutputSection() removed.

Differential revision: https://reviews.llvm.org/D22617

llvm-svn: 276283
2016-07-21 14:26:59 +00:00
Rui Ueyama fd03cfd27a Instantiate Interp output section only when needed.
This change simplifies interaction between Writer and the linker script
because we can make needsInterpSection() a file-scope function.

llvm-svn: 276261
2016-07-21 11:01:23 +00:00
Simon Atanasyan 4f90c2f9df [ELF][MIPS] Omit redundant arguments in the `getMipsEFlags` function. NFC
llvm-svn: 276176
2016-07-20 20:30:41 +00:00
Simon Atanasyan f463709d7d [ELF][MIPS] Pick arch flag from the first input file.
LLD still does not produce a correct combination of MIPS ELF flags if
input files have different sets of ELF flags (i.e. EF_MIPS_ARCH_32 and
EF_MIPS_ARCH_32R2). But now we do not stick to "R2" ABI version and can
emit EF_MIPS_ARCH_32R6 for example.

llvm-svn: 276172
2016-07-20 20:15:24 +00:00
Rui Ueyama 18f084ff62 Function names should start with lowercase letters.
llvm-svn: 276165
2016-07-20 19:36:41 +00:00
Rui Ueyama 703296aeda Return a vector from createPhdrs instead of return nothing.
This way is consistent with createSections.

llvm-svn: 276164
2016-07-20 19:36:39 +00:00
Chandler Carruth 1d175fbc46 Add yet more explicit template instantiations. These were always needed
but things happened to work on some platforms prior to r276133. This
should be the complete set (I hope).

llvm-svn: 276155
2016-07-20 18:47:33 +00:00
Rafael Espindola 0f7cedaa1e Create thunks before regular relocation scan.
We will need to do something like this to support range extension
thunks since that process is iterative.

Doing this also has the advantage that when doing the regular
relocation scan the offset in the output section is known and we can
just store that. This reduces the number of times we have to run
getOffset and I think will allow a more specialized .eh_frame
representation.

By itself this is already a performance win.

firefox
  master 7.295045737
  patch  7.209466989 0.98826892235
chromium
  master 4.531254468
  patch  4.509221804 0.995137623774
chromium fast
  master 1.836928973
  patch  1.823805241 0.992855612714
the gold plugin
  master 0.379768791
  patch  0.380043405 1.00072310839
clang
  master 0.642698284
  patch  0.642215663 0.999249070657
llvm-as
  master 0.036665467
  patch  0.036456225 0.994293213284
the gold plugin fsds
  master 0.40395817
  patch  0.404384555 1.0010555177
clang fsds
  master 0.722045545
  patch  0.720946135 0.998477367518
llvm-as fsds
  master 0.03292646
  patch  0.032759965 0.994943428477
scylla
  master 3.427376378
  patch  3.368316181 0.98276810292

llvm-svn: 276146
2016-07-20 17:58:07 +00:00
Rui Ueyama a7f7884df8 Simplify output section ownership.
This patch simplifies output section management by making
Factory class have ownership of sections that creates.

Differential Revision: https://reviews.llvm.org/D22575

llvm-svn: 276141
2016-07-20 17:19:03 +00:00
Eugene Leviant f2ea038a4e [ELF] Attempt to fix FreeBSD build bot (no template instantiation for getOutputSectionName)
llvm-svn: 276133
2016-07-20 15:42:34 +00:00
Eugene Leviant e63d81bd05 [ELF] Create output sections in LinkerScript class
llvm-svn: 276121
2016-07-20 14:43:20 +00:00
Rafael Espindola 74df5c7eeb Fix build with gcc 6.
llvm-svn: 275972
2016-07-19 12:33:46 +00:00
Eugene Leviant bbe3860244 [ELF] Minimal PHDRS parser and section to segment assignment support
llvm-svn: 275965
2016-07-19 09:25:43 +00:00
Rui Ueyama e33579072d Remove SymbolBody::PlaceholderKind.
In the last patch for --trace-symbol, I introduced a new symbol type
PlaceholderKind and store it to SymVector storage. It made all code
that iterates over SymVector to recognize and skip PlaceholderKind
symbols. I found that that's annoying.

In this patch, I removed PlaceholderKind and stop storing them to SymVector.
Now the information whether a symbol is being watched by --trace-symbol
is stored to the Symtab hash table.

llvm-svn: 275747
2016-07-18 01:35:00 +00:00
Rui Ueyama 25a6d57b9c Unbreak msan buildbot.
llvm-svn: 275728
2016-07-17 19:55:22 +00:00
Rui Ueyama 434b56179e Add a pointer to a source file to SymbolBody.
Previously, each subclass of SymbolBody had a pointer to a source
file from which it was created. So, there was no single way to get
a source file for a symbol. We had getSourceFile<ELFT>(), but the
function was a bit inconvenient as it's a template.

This patch makes SymbolBody have a pointer to a source file.
If a symbol is not created from a file, the pointer has a nullptr.

llvm-svn: 275701
2016-07-17 03:11:46 +00:00
Rui Ueyama 818bb2f8dc Remove redundant namespace specifiers.
llvm-svn: 275694
2016-07-16 18:55:47 +00:00
Rui Ueyama c755599997 Simplify. NFC.
llvm-svn: 275675
2016-07-16 04:19:29 +00:00
Rui Ueyama af469d47e9 Rename SymbolVersions VersionDefinitions.
SymbolVersions sounds like it had versions for a symbol, so rename it.

llvm-svn: 275674
2016-07-16 04:09:27 +00:00
Rui Ueyama f8292e9ac9 ELF: Make check() always return a value.
This patch corresponds to r275511 for COFF.

llvm-svn: 275521
2016-07-15 02:01:03 +00:00
Rui Ueyama aa2db88984 ELF: Make error() to always set HasError.
Previously, it checked for the EC parameter and set HasError
only when there was an error. But in most places we called
error only when error had occurred, so this behavior was confusing.

llvm-svn: 275517
2016-07-15 01:38:54 +00:00
Rui Ueyama 484a49514f Rename VAStart -> ImageBase. NFC.
Config members are named after corresponding command line options.
This patch renames VAStart ImageBase so that they are in line with
--image-base.

Differential Revision: http://reviews.llvm.org/D22277

llvm-svn: 275298
2016-07-13 18:40:59 +00:00
George Rimar bd69903692 [ELF] - Add predefined sections to output sections list in one place.
Minor cleanup.
Currently it looks wierd that having method addPredefinedSections()
we still add 2 sections outside it without real reasons.
Patch fixes that.

Differential revision: http://reviews.llvm.org/D19981

llvm-svn: 275269
2016-07-13 14:26:31 +00:00
Petr Hosek d7bd2389ce [ELF] Support for setting the base address
The -image-base option allows for overriding the base address.

Differential Revision: http://reviews.llvm.org/D22116

llvm-svn: 275206
2016-07-12 19:37:53 +00:00
George Rimar 6892afaa2d Recommit r275161 "[ELF] - Move section factory out from writer to make it reusable."
With fix:
* fixed compilation error under linux:

template <class ELFT> class OutputSectionFactory {
...
  typedef typename SectionKey<ELFT::Is64Bits> Key;

changed to:
template <class ELFT> class OutputSectionFactory {
...
  typedef typename elf::SectionKey<ELFT::Is64Bits> Key;

llvm-svn: 275166
2016-07-12 09:49:43 +00:00
George Rimar d8f547fab4 Revert r275161 "[ELF] - Move section factory out from writer to make it reusable."
It broke build bot:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-debian-fast/builds/39652

llvm-svn: 275163
2016-07-12 09:11:13 +00:00
George Rimar 5d53d1f42c [ELF] - Make few members of Writer to be global and export them for reuse
Creating sections on linkerscript side requires some methods
that can be reused if are exported from writer.

Patch implements that change.

Differential revision: http://reviews.llvm.org/D20104

llvm-svn: 275162
2016-07-12 08:50:42 +00:00
George Rimar e51f7f4d39 [ELF] - Move section factory out from writer to make it reusable.
Since linkerscript should create sections by itself
(if SECTIONS command is present),
then we might want to reuse the OutputSectionFactory (D19976 already do that now),
so this patch moves it out from writer cpp file for that purpose.

Differential revision: http://reviews.llvm.org/D19977

llvm-svn: 275161
2016-07-12 08:38:04 +00:00
Eugene Leviant eda81a1b86 [ELF] Support for symbol assignment in linker scripts within SECTIONS {} block
llvm-svn: 275158
2016-07-12 06:39:48 +00:00
Rui Ueyama 52c4e17f8a Remove trailing whitespaces.
llvm-svn: 274343
2016-07-01 10:42:25 +00:00
Eugene Leviant 467c4d5538 [ELF] Fix first PT_LOAD segment VA calculation, when linker script is used
llvm-svn: 274342
2016-07-01 10:27:36 +00:00
George Rimar e86dcd0cbd [ELF] - Added support for --unresolved-symbols option.
Option has next description (http://linux.die.net/man/1/ld):
"--unresolved-symbols=method
Determine how to handle unresolved symbols. There are four possible values for method
according to documentation:

ignore-all: Do not report any unresolved symbols.
report-all: Report all unresolved symbols. This is the default.
ignore-in-object-files: Report unresolved symbols that are contained in shared libraries, but ignore them if they come from regular object files.
ignore-in-shared-libs: Report unresolved symbols that come from regular object files, but ignore them if they come from shared libraries."

Since report-all is default and we traditionally do not report about undefined symbols in lld,
report-all does not report about undefines from DSO. 
ignore-in-object-files also does not do that. Handling of that option differs from what gnu linkers do.

Option works in next way in lld:
ignore-all: Do not report any unresolved symbols.
report-all: Report all unresolved symbols except symbols from DSOs. This is the default.
ignore-in-object-files: The same as ignore-all.
gnore-in-shared-libs: The same as report-all.

This is PR24524.

Differential revision: http://reviews.llvm.org/D21794

llvm-svn: 274123
2016-06-29 12:35:04 +00:00
Rui Ueyama fbbde548cf Move isValidCIdentifier to Strings.cpp.
llvm-svn: 274112
2016-06-29 09:08:02 +00:00
Rui Ueyama 5e64d3fb94 Refactor ELF type inference functions.
Previously, we initialized Config->EKind and Config->EMachine when
we instantiate ELF objects. That was not an ideal location to do that
because the logic was buried too deep inside a concrete logic.

This patch moves the code to the driver so that the initialization
becomes explicit.

Differential Revision: http://reviews.llvm.org/D21784

llvm-svn: 274089
2016-06-29 01:30:50 +00:00
George Rimar d84f21b288 [ELF] - Remove Config->ZDefs flag.
-z defs is the same as --no-undefined (http://linux.die.net/man/1/ld).
It looks to be a error to handle it separatelly.

Differential revision: http://reviews.llvm.org/D21788

llvm-svn: 274003
2016-06-28 12:04:19 +00:00
George Rimar 602fbee9fc [ELF] - Support of compressed input sections implemented.
Patch implements support of zlib style compressed sections.
SHF_COMPRESSED flag is used to recognize that decompression is required.
After that decompression is performed and flag is removed from output.

Differential revision: http://reviews.llvm.org/D20272

llvm-svn: 273661
2016-06-24 11:18:44 +00:00
Rui Ueyama 809d8e2d41 Fix a bug that MIPS thunks can overwrite other section contents.
Peter Smith found while trying to support thunk creation for ARM that
LLD sometimes creates broken thunks for MIPS. The cause of the bug is
that we assign file offsets to input sections too early. We need to
create all sections and then assign section offsets because appending
thunks changes file offsets for all following sections.

This patch separates the pass to assign file offsets from thunk
creation pass. This effectively reverts r265673.

Differential Revision: http://reviews.llvm.org/D21598

llvm-svn: 273532
2016-06-23 04:33:42 +00:00
George Rimar d5d544757e [ELF] - Removed excessive reference from pointer arguments. NFC.
llvm-svn: 273155
2016-06-20 13:30:37 +00:00
George Rimar 086fcae95e [ELF] - Forgot to address these two minors before commit r273152. NFC.
llvm-svn: 273154
2016-06-20 13:22:54 +00:00
George Rimar d3566309eb [ELF] - Recommit r273143("[ELF] - Basic versioned symbols support implemented.")
With fix:
-soname flag was not set in testcase. Hash calculated for base def was different on local
and bot machines because filename fos used for calculating.

Initial commit message:
Patch implements basic support of versioned symbols.
There is no wildcards patterns matching except local: *;
There is no support for hierarchies.
There is no support for symbols overrides (@ vs @@ not handled).

This patch allows programs that using simple scripts to link and run.

Differential revision: http://reviews.llvm.org/D21018

llvm-svn: 273152
2016-06-20 11:55:12 +00:00
George Rimar d03f97211a Revert r273143 "[ELF] - Basic versioned symbols support implemented."
It broke buildbot:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast

llvm-svn: 273146
2016-06-20 10:29:53 +00:00
George Rimar c31fee2212 [ELF] - Basic versioned symbols support implemented.
Patch implements basic support of versioned symbols.
There is no wildcards patterns matching except local: *;
There is no support for hierarchies.
There is no support for symbols overrides (@ vs @@ not handled).

This patch allows programs that using simple scripts to link and run.

Differential revision: http://reviews.llvm.org/D21018

llvm-svn: 273143
2016-06-20 10:16:33 +00:00
Rui Ueyama 424b408165 Rename Align -> Alignment.
I think it is me who named these variables, but I always find that
they are slightly confusing because align is a verb.
Adding four letters is worth it.

llvm-svn: 272984
2016-06-17 01:18:46 +00:00
Peter Collingbourne ca8c994818 ELF: Compute used bit for --as-needed during symbol resolution.
We can now use this to decide whether to emit a verneed during the final
pass over the symbols. We were previously wrongly creating a verneed entry
in the case where all references to a DSO's symbols were weak.

In a future change we may also want to use the used bit to control whether
shared symbols are preemptible and appear in the dynsym. This seems a little
tricky to do at the moment because isNeeded() is templated.

The only other functional change here is that we emit a DT_NEEDED for DSOs
whose symbols are all preempted by objects that appear later in the link. But
that doesn't seem too important to me.

Differential Revision: http://reviews.llvm.org/D21171

llvm-svn: 272282
2016-06-09 18:01:35 +00:00
Rui Ueyama 406b469de4 Avoid doing binary search.
MergedInputSection::getOffset is the busiest function in LLD if string
merging is enabled and input files have lots of mergeable sections.
It is usually the case when creating executable with debug info,
so it is pretty common.

The reason why it is slow is because it has to do faily complex
computations. For non-mergeable sections, section contents are
contiguous in output, so in order to compute an output offset,
we only have to add the output section's base address to an input
offset. But for mergeable strings, section contents are split for
merging, so they are not contigous. We've got to do some lookups.

We used to do binary search on the list of section pieces.
It is slow because I think it's hostile to branch prediction.

This patch replaces it with hash table lookup. Seems it's working
pretty well. Below is "perf stat -r10" output when linking clang
with debug info. In this case this patch speeds up about 4%.

Before:

       6584.153205 task-clock (msec)         #    1.001 CPUs utilized            ( +-  0.09% )
               238 context-switches          #    0.036 K/sec                    ( +-  6.59% )
                 0 cpu-migrations            #    0.000 K/sec                    ( +- 50.92% )
         1,067,675 page-faults               #    0.162 M/sec                    ( +-  0.15% )
    18,369,931,470 cycles                    #    2.790 GHz                      ( +-  0.09% )
     9,640,680,143 stalled-cycles-frontend   #   52.48% frontend cycles idle     ( +-  0.18% )
   <not supported> stalled-cycles-backend
    21,206,747,787 instructions              #    1.15  insns per cycle
                                             #    0.45  stalled cycles per insn  ( +-  0.04% )
     3,817,398,032 branches                  #  579.786 M/sec                    ( +-  0.04% )
       132,787,249 branch-misses             #    3.48% of all branches          ( +-  0.02% )

       6.579106511 seconds time elapsed                                          ( +-  0.09% )

After:

       6312.317533 task-clock (msec)         #    1.001 CPUs utilized            ( +-  0.19% )
               221 context-switches          #    0.035 K/sec                    ( +-  4.11% )
                 1 cpu-migrations            #    0.000 K/sec                    ( +- 45.21% )
         1,280,775 page-faults               #    0.203 M/sec                    ( +-  0.37% )
    17,611,539,150 cycles                    #    2.790 GHz                      ( +-  0.19% )
    10,285,148,569 stalled-cycles-frontend   #   58.40% frontend cycles idle     ( +-  0.30% )
   <not supported> stalled-cycles-backend
    18,794,779,900 instructions              #    1.07  insns per cycle
                                             #    0.55  stalled cycles per insn  ( +-  0.03% )
     3,287,450,865 branches                  #  520.799 M/sec                    ( +-  0.03% )
        72,259,605 branch-misses             #    2.20% of all branches          ( +-  0.01% )

       6.307411828 seconds time elapsed                                          ( +-  0.19% )

Differential Revision: http://reviews.llvm.org/D20645

llvm-svn: 270999
2016-05-27 14:39:13 +00:00
Rui Ueyama 0fcdc730ad Create Relocations.cpp and move scanRelocs there.
scanReloc and the functions on which scanReloc depends is in total
more than 600 lines of code. Since scanReloc does not depend on Writer,
it is better to move it into a separate file.

Differential Revision: http://reviews.llvm.org/D20554

llvm-svn: 270606
2016-05-24 20:24:43 +00:00
Rafael Espindola fe3a2f1b81 Revert "Simplify. Thanks to Rui for the suggestion."
This reverts commit r270551.

Sorry, I commited the wrong branch :-(

llvm-svn: 270554
2016-05-24 12:12:06 +00:00
Rafael Espindola dba64b8ea4 Simplify. Thanks to Rui for the suggestion.
llvm-svn: 270551
2016-05-24 11:53:15 +00:00
Rui Ueyama ace4f90cf3 Do not pass the symbol table. NFC.
Since the symbol table is a singleton class and globally accessible,
we don't need to pass it around.

llvm-svn: 270533
2016-05-24 04:25:47 +00:00
Rui Ueyama 0b9a90364b Rename EHInputSection -> EhInputSection.
llvm-svn: 270532
2016-05-24 04:19:20 +00:00
Rui Ueyama 022d8e8a86 Make scanReloc and related functions non-member functions.
scanReloc does not depend on Writer, so it doesn't have to be
in the class.

llvm-svn: 270530
2016-05-24 03:36:07 +00:00
Rui Ueyama afa35a2a37 Remove Writer::ensureBss().
Previously, we created a .bss section when needed. We had a function
ensureBss() for that purpose. Turned out that was error-prone
because it was easy to forget to call that function before accessing
the .bss section.

This patch always make the BSS section. The section is added to the
output when it's not empty.

llvm-svn: 270527
2016-05-24 03:16:51 +00:00
Rui Ueyama 98843087cb Reject zero-sized symbols when creating copy relocations.
Copy relocations are relocations to copy data from DSOs to
executable's .bss segment at runtime. It doesn't make sense to
create such relocations for zero-sized symbols.

GNU linkers don't agree with each other. ld rejects such
relocation/symbol pair. gold don't reject that but do not create
copy relocations as well.  I took the former approach because
I don't think the latter is what user wants.

llvm-svn: 270525
2016-05-24 02:37:40 +00:00
Rui Ueyama 8a6ef4e6b2 Remove dead code.
Since now we always set SHT_PROGBITS to .eh_frame sections,
this code path is not executed at runtime.

llvm-svn: 270446
2016-05-23 16:24:22 +00:00
Rui Ueyama 3b31e6711b Make .eh_frame a singleton output object.
.eh_frame_hdr assumes that there is only one .eh_frame and
ensures it by assertions. This patch makes .eh_frame a real
singleton object to simplify.

llvm-svn: 270445
2016-05-23 16:24:16 +00:00
Rui Ueyama f86cb90a2d Do not propagate section name and attributes to .eh_frame.
.eh_frame is always ".eh_frame" and its attribute is fixed.
No need to copy from inputs to outputs. GNU gold also sets
SHT_PROGBITS.

llvm-svn: 270443
2016-05-23 15:12:41 +00:00
Rui Ueyama 1e479c23aa Rename EHOutputSection -> EhOutputSection for consistency.
llvm-svn: 270442
2016-05-23 15:07:59 +00:00
Rui Ueyama 90fa3722d2 Simplify SplitInputSection::getRangeAndSize.
This patch adds Size member to SectionPiece so that getRangeAndSize
can just return a SectionPiece instead of a std::pair<SectionPiece *, uint_t>.
Also renamed the function.

llvm-svn: 270346
2016-05-22 00:41:38 +00:00
Rui Ueyama 3ea8727188 Define SectionPiece and use it instead of std::pair<uint_t, uint_t>.
We were using std::pair to represents pieces of splittable section
contents. It hurt readability because "first" and "second" are not
meaningful. This patch give them names.

One more thing is that piecewise liveness information is stored to
the second element of the pair as a special value of output section
offset. It was confusing, so I defiend a new bit, "Live", in the
new struct.

llvm-svn: 270340
2016-05-22 00:13:04 +00:00
Rafael Espindola ebed1fe0de Refactor R_RELAX_TLS_* value computation.
This makes it explicit that each R_RELAX_TLS_* is equivalent to some
other expression.

With this I think we are at a sweet spot for how much is done in
Target.cpp. I did experiment with moving *all* the value math out of it.
It has the advantage that we know the final value in target independent
code, but it gets quite verbose.

llvm-svn: 270277
2016-05-20 21:23:52 +00:00
Rafael Espindola 6989ebf661 Simplify, NFC.
llvm-svn: 269983
2016-05-18 21:05:18 +00:00
Rafael Espindola e4c86d83fe Drop vestigial support for UseLazyBinding=false.
Lazy binding is quite important for use case like a shared build of
llvm. Also, if someone wants to disable it, it is better done in the
compiler (disable plt generation).

The only reason to keep it is to make it easier to add a new
architecture. But it doesn't really help much as it is possible to start
with non lazy relocation and plt code but still let the generic part
create a dedicated .got.plt and .rela.plt.

llvm-svn: 269982
2016-05-18 21:03:36 +00:00
Simon Atanasyan 4e3a15c9f3 [ELF][MIPS] Rename R_MIPS_GOT_xxx relocation expression kinds
New names reflect purpose of corresponding GOT entries better.
Both expression types related to entries allocated in the 'local'
part of MIPS GOT. R_MIPS_GOT_LOCAL_PAGE is for entries contain 'page'
addresses. R_MIPS_GOT_LOCAL is for entries contain 'full' address.

llvm-svn: 269597
2016-05-15 18:13:50 +00:00
Rui Ueyama 9194db78fb Support --build-id=0x<hexstring>.
If you specify the option in the form of --build-id=0x<hexstring>,
that hexstring is set as a build ID. We observed that the feature
is actually in use in some builds, so we want this feature.

llvm-svn: 269495
2016-05-13 21:55:56 +00:00
Rafael Espindola 7229496787 When using Rela, don't write the addend to the output section.
The Elf_Rela has an explicit addend. It doesn't need the addend to be
written to the section being relocated.

Since relative relocations are very common in the output, this is a
noticeable speedup. The results I got were

chromium
  master 4.778149487
  patch  4.761120792 0.996436131802
chromium fast
  master 1.896253636
  patch  1.840990582 0.970856718241
the gold plugin
  master 0.399337811
  patch  0.392279276 0.982324401032
clang
  master 0.666873675
  patch  0.665895708 0.998533504865
llvm-as
  master 0.037101095
  patch  0.037123149 1.00059442989
the gold plugin fsds
  master 0.422473396
  patch  0.414192879 0.980399909016
clang fsds
  master 0.747302008
  patch  0.744843964 0.996710775599
llvm-as fsds
  master 0.033146245
  patch  0.033064531 0.997534743377
scylla
  master 4.08857525
  patch  4.082245184 0.998451767275

llvm-svn: 269417
2016-05-13 14:15:37 +00:00
Rafael Espindola 686ffc6f4c Slit the relocation scan in two parts.
The first part handles whatever has to be written to the r_offset
position.

The second part handles creating got and plt entries.

llvm-svn: 269375
2016-05-12 22:51:22 +00:00
Rafael Espindola 203b0773a3 Move addend computation to a helper function.
llvm-svn: 269369
2016-05-12 22:19:35 +00:00
Rafael Espindola 01f1636408 Handle thunks in adjustExpr.
This is similar to the other changes this function does. With this all
Relocations.push_back calls look similar.

llvm-svn: 269362
2016-05-12 21:53:34 +00:00
Rafael Espindola 62cb02eef1 This reverts commit r269359 and r269360.
I will commit again with a fixed commit message.

llvm-svn: 269361
2016-05-12 21:51:16 +00:00
Rafael Espindola cc42a90b76 Handle thunks in adjustExpr.
This is similar to the other changes this function does. With this all
Relocations.push_back calls look similar.

llvm-svn: 269360
2016-05-12 21:47:26 +00:00
Rafael Espindola 01a94f8336 bra
llvm-svn: 269359
2016-05-12 21:47:24 +00:00
George Rimar fa91000290 [ELF] implemented -z defs option
Just do not allow to link shared library if there are
undefined symbols.

This fixes PR27447

Differential revision: http://reviews.llvm.org/D20169

llvm-svn: 269183
2016-05-11 13:48:41 +00:00
George Rimar c191acf097 [ELF] - Implemented -z combrelocs/nocombreloc.
This is the option which sorts relocs to optimize dynamic linker performance.
-z combelocs is the default in gold, also it ignores -z nocombreloc,
this patch do the same.

Patch sorts relocations by symbols only and do not create any
DT_REL[A]COUNT entries. That is different with what gold/bfd do.

More information about option is here:
http://www.airs.com/blog/archives/186
http://people.redhat.com/jakub/prelink.pdf, p.2

Differential revision: http://reviews.llvm.org/D19528

llvm-svn: 269066
2016-05-10 15:47:57 +00:00
Rafael Espindola 78db5a9dca Print member name in undefined symbol error.
llvm-svn: 268976
2016-05-09 21:40:06 +00:00
Rafael Espindola 45a33fb799 Allow user defined __init_aray_start.
Fixes pr27683.

llvm-svn: 268926
2016-05-09 15:25:54 +00:00
Simon Atanasyan 9ac819860f [ELF][MIPS] Reduce all MIPS R_GOTREL addends by MipsGPOffset in the single place. NFC
llvm-svn: 268742
2016-05-06 15:02:50 +00:00
Simon Atanasyan 1a728fdf5c [ELF][MIPS] Simplify `if` condition. NFC
In case of MIPS ABI relocation has R_GOTREL expression's type iif the
relocation type is either R_MIPS_GPREL16 or R_MIPS_GPREL32. So it is
enough to check expression's type only.

llvm-svn: 268741
2016-05-06 15:02:45 +00:00
Rafael Espindola d39dadeb64 Don't produce a relocation to read only memory.
This is hopefully last case where we would produce a relocation to a
read only section.

llvm-svn: 268688
2016-05-05 21:19:38 +00:00
Rafael Espindola 66434562e7 Fix copy relocations in pie.
We were creating the copy relocations just fine, but then thinking that
the .bss position could be preempted and creating a dynamic relocation
to it, which would crash at runtime since that memory is read only.

llvm-svn: 268668
2016-05-05 19:41:49 +00:00
Peter Collingbourne 3ad1c1e242 ELF: Undefine all symbols, not just those that we expect to be defined.
This allows the combined LTO object to provide a definition with the same
name as a symbol that was internalized without causing a duplicate symbol
error. This normally happens during parallel codegen which externalizes
originally-internal symbols, for example.

In order to make this work, I needed to relax the undefined symbol error to
only report an error for symbols that are used in regular objects.

Differential Revision: http://reviews.llvm.org/D19954

llvm-svn: 268649
2016-05-05 17:13:49 +00:00
Rafael Espindola 474eb019b4 Move static function to avoid forward declaration. NFC.
llvm-svn: 268646
2016-05-05 16:40:28 +00:00
Rafael Espindola 462220de47 Reuse logic for deciding whether to keep a local symbol or not.
llvm-svn: 268644
2016-05-05 16:38:46 +00:00
Peter Collingbourne e29e142a10 ELF: Do not use -1 to mark pieces of merge sections as being tail merged.
We were previously using an output offset of -1 for both GC'd and tail
merged pieces. We need to distinguish these two cases in order to filter
GC'd symbols from the symbol table -- we were previously asserting when we
asked for the VA of a symbol pointing into a dead piece, which would end
up asking the tail merging string table for an offset even though we hadn't
initialized it properly.

This patch fixes the bug by using an offset of -1 to exclusively mean GC'd
pieces, using 0 for tail merges, and distinguishing the tail merge case from
an offset of 0 by asking the output section whether it is tail merge.

Differential Revision: http://reviews.llvm.org/D19953

llvm-svn: 268604
2016-05-05 04:10:12 +00:00
Rafael Espindola de17d28a32 Don't produce relative relocs to ro segments.
We were already checking for non relative relocations.

If we ever decide to add support for rw text segments this means we will
have a single spot to add the flag.

llvm-svn: 268558
2016-05-04 21:40:07 +00:00
Rafael Espindola 3fa5bbd91b Rename isRelRelative.
What it is computing is if we need a dynamic relocation or not.

llvm-svn: 268556
2016-05-04 21:28:56 +00:00
Rafael Espindola 946ca27b61 Use early return. NFC.
llvm-svn: 268554
2016-05-04 21:09:24 +00:00
Rafael Espindola 38bd217d0c Delete getTlsGotRel.
It was an old hack to avoid duplicating expression computation, but that
is not needed with getExprRel.

llvm-svn: 268515
2016-05-04 15:51:23 +00:00
Rafael Espindola ebb04b9eb6 Simplify handling of hint relocations.
llvm-svn: 268501
2016-05-04 14:44:22 +00:00
Simon Atanasyan add74f37f2 [ELF][MIPS] Read/write .MIPS.options section
MIPS N64 ABI introduces .MIPS.options section which specifies miscellaneous
options to be applied to an object/shared/executable file. LLVM as well as
modern versions of GNU tools read and write the only type of the options -
ODK_REGINFO. It is exact copy of .reginfo section used by O32 ABI.

llvm-svn: 268485
2016-05-04 10:07:38 +00:00
Peter Collingbourne 6f535b744f Check return value of addOptionalSynthetic before calling a member function on it.
Found with UBSan.

llvm-svn: 268410
2016-05-03 18:03:45 +00:00
Peter Collingbourne c357278a38 ELF: Remove the function SymbolTable<ELFT>::findFile.
We already have the function SymbolBody::getSourceFile which does the same thing.

llvm-svn: 268353
2016-05-03 01:48:25 +00:00
Peter Collingbourne 6a4225962d ELF: Forbid all relative relocations to absolute symbols in PIC, except for weak undefined.
Weak undefined symbols resolve to the image base. This is a little strange,
but it allows us to link function calls to such symbols. Normally such a
call will be guarded with a comparison, which will load a zero from the GOT.

There's one example of such a function call in crti.o in Linux's CRT.

As part of this change, I also needed to make the synthetic start and end
symbols image base relative in the case where their sections were empty,
so that PC-relative references to those symbols would continue to work.

Differential Revision: http://reviews.llvm.org/D19844

llvm-svn: 268350
2016-05-03 01:21:08 +00:00
Rui Ueyama dd368fcb05 Pass all buffers to BuildId hash function at once. NFC.
This change simplifies the BuildId classes by removing a few member
functions and variables from them. It should also make it easy to
parallelize hash computation in future because now each BuildId object
see all inputs rather than one at a time.

llvm-svn: 268333
2016-05-02 23:35:59 +00:00
Simon Atanasyan 63dcba05b7 Replace non-ascii character.
llvm-svn: 268218
2016-05-02 09:49:03 +00:00
Peter Collingbourne f643fc10d1 Further MSVC appeasement.
llvm-svn: 268185
2016-05-01 05:39:02 +00:00
Peter Collingbourne 4f9527065c ELF: New symbol table design.
This patch implements a new design for the symbol table that stores
SymbolBodies within a memory region of the Symbol object. Symbols are mutated
by constructing SymbolBodies in place over existing SymbolBodies, rather
than by mutating pointers. As mentioned in the initial proposal [1], this
memory layout helps reduce the cache miss rate by improving memory locality.

Performance numbers:

           old(s) new(s)
Without debug info:
chrome      7.178  6.432 (-11.5%)
LLVMgold.so 0.505  0.502 (-0.5%)
clang       0.954  0.827 (-15.4%)
llvm-as     0.052  0.045 (-15.5%)
With debug info:
scylla      5.695  5.613 (-1.5%)
clang      14.396 14.143 (-1.8%)

Performance counter results show that the fewer required indirections is
indeed the cause of the improved performance. For example, when linking
chrome, stalled cycles decreases from 14,556,444,002 to 12,959,238,310, and
instructions per cycle increases from 0.78 to 0.83. We are also executing
many fewer instructions (15,516,401,933 down to 15,002,434,310), probably
because we spend less time allocating SymbolBodies.

The new mechanism by which symbols are added to the symbol table is by calling
add* functions on the SymbolTable.

In this patch, I handle local symbols by storing them inside "unparented"
SymbolBodies. This is suboptimal, but if we do want to try to avoid allocating
these SymbolBodies, we can probably do that separately.

I also removed a few members from the SymbolBody class that were only being
used to pass information from the input file to the symbol table.

This patch implements the new design for the ELF linker only. I intend to
prepare a similar patch for the COFF linker.

[1] http://lists.llvm.org/pipermail/llvm-dev/2016-April/098832.html

Differential Revision: http://reviews.llvm.org/D19752

llvm-svn: 268178
2016-05-01 04:55:03 +00:00
Rafael Espindola a85efd985c Don't create dynamic relocations to ro segments.
These would just crash at runtime.

If we ever decide to support rw text segments this should make it easier
to implement as there is now a single point where we notice the problem.

I have tested this with a freebsd buildworld. It found a non pic
assembly file being linked into a .so,. With that fixed, buildworld
finished.

llvm-svn: 268149
2016-04-30 01:15:17 +00:00
Simon Atanasyan ae77ab71d8 [ELF][MIPS] Accept MIPS 64-bit binaries
LLD accepts MIPS 64-bit binaries, supports corresponding eulation (-m)
arguments and emits 64-bit specific ELF flags.

llvm-svn: 268024
2016-04-29 10:39:17 +00:00
Rui Ueyama 2b6fb80384 Skip scanRelocs for non-alloc sections.
Relocations against sections with no SHF_ALLOC bit are R_ABS relocations.
Currently we are creating Relocations vector for them, but that is wasteful.
This patch is to skip vector construction and to directly apply relocations
in place.

This patch seems to be pretty effective for large executables with debug info.
r266158 (Rafael's patch to change the way how we apply relocations) caused a
temporary performance degradation for such executables, but this patch makes
it even faster than before.

Time to link clang with debug info (output size is 1070 MB):

  before r266158: 15.312 seconds (0%)
  r266158:        17.301 seconds (+13.0%)
  Head:           16.484 seconds (+7.7%)
  w/patch:        13.166 seconds (-14.0%)

Differential Revision: http://reviews.llvm.org/D19645

llvm-svn: 267917
2016-04-28 18:42:04 +00:00
Rafael Espindola b8ff59ac12 Rename isRelRelative
It was never a particularly good name and is now completely out of date.

llvm-svn: 267886
2016-04-28 14:34:39 +00:00
George Rimar 959d180fa6 Fixed mistype in comment. NFC.
llvm-svn: 267878
2016-04-28 13:38:10 +00:00
Rui Ueyama e5c1ec4716 Add comment.
llvm-svn: 267847
2016-04-28 03:04:15 +00:00
Peter Collingbourne 21a12fc69a ELF: Create .gnu.version and .gnu.version_r sections when linking against versioned DSOs.
Differential Revision: http://reviews.llvm.org/D19464

llvm-svn: 267775
2016-04-27 20:22:31 +00:00
Rafael Espindola 7ac9628648 Reduce usage of isRelRelative.
It is now used only for relocations that only set the low bits inside a
page. Everything else is handled by getRelExpr.

I will send a another review renaming and better documenting
isRelRelative.

llvm-svn: 267705
2016-04-27 12:47:30 +00:00
Rafael Espindola 520ed3a621 Create a .got when PPC64 uses a TOC.
This simplifies the logic for computing the value of the toc base.

llvm-svn: 267701
2016-04-27 12:21:27 +00:00
Rafael Espindola 365e5f69c9 Simplify handling of R_PPC64_TOC. NFC.
llvm-svn: 267698
2016-04-27 11:54:07 +00:00
George Rimar 5f85732738 [ELF] - Align sections file offsets correctly.
System V ABI 4.1 specifies that program header's p_vaddr should equal p_offset, modulo p_align. 
(https://docs.oracle.com/cd/E19683-01/816-1386/chapter6-83432/index.html).
It was possible to violate this using the linkerscript.
Patch fixes the issue.

Differential revision: http://reviews.llvm.org/D19416

llvm-svn: 267684
2016-04-27 09:16:28 +00:00
Rui Ueyama 389aa8e91e Simplify. NFC.
llvm-svn: 267663
2016-04-27 03:04:56 +00:00
Peter Collingbourne 892d498017 ELF: Re-implement -u directly and remove CanKeepUndefined flag.
The semantics of the -u flag are to load the lazy symbol named by the flag. We
were previously relying on this behavior falling out of symbol resolution
against a synthetic undefined symbol, but that didn't quite give us the
correct behavior, so we needed a flag to mark symbols created with -u so
we could treat them specially in the writer. However, it's simpler and less
error prone to implement the required behavior directly and remove the flag.

This fixes an issue where symbols loaded with -u would receive hidden
visibility even when the definition in an object file had wider visibility.

Differential Revision: http://reviews.llvm.org/D19560

llvm-svn: 267639
2016-04-27 00:05:03 +00:00
Peter Collingbourne 676c7cd1ed ELF: Move code to where it is used, and related cleanups. NFC.
Differential Revision: http://reviews.llvm.org/D19490

llvm-svn: 267637
2016-04-26 23:52:44 +00:00
Rafael Espindola 1763dc44b9 Return R_GOTREL for R_MIPS_GPREL*.
This lets Writer.cpp know that they are got relative, which will allow
further simplifications.

llvm-svn: 267613
2016-04-26 22:00:04 +00:00
Rafael Espindola 6c75238aca Call repl in getSymbolBody. NFC.
Every caller was doing it.

llvm-svn: 267603
2016-04-26 20:45:31 +00:00
Rafael Espindola 0baa73f317 Handle --as-needed with symbols, not relocations.
This matches the behavior of both gold and bfd.

llvm-svn: 267558
2016-04-26 13:56:26 +00:00
Rafael Espindola 9e32e4fe86 Store the binding in the Symbol.
This remove a fixme, cleans up the weak undef interaction with archives and
lets us keep weak undefs still weak if they resolve to shared.

llvm-svn: 267555
2016-04-26 13:50:46 +00:00
Rafael Espindola a6c4d2f197 Delete needsCopyRelImpl. It is redundant with getRelExpr.
llvm-svn: 267394
2016-04-25 12:05:56 +00:00
Simon Atanasyan c245d84213 [ELF] Delete extra line. NFC
llvm-svn: 267391
2016-04-25 10:18:48 +00:00
Peter Collingbourne 6d01a35ef6 ELF: Forbid undefined symbols with non-default visibility in DSOs.
llvm-svn: 267315
2016-04-24 02:31:04 +00:00
Rafael Espindola 0b9531c8e6 Bring r267164 back with a fix.
The fix is to handle local symbols referring to SHF_MERGE sections.

Original message:

GC entries of SHF_MERGE sections.

It is a fairly direct extension of the gc algorithm. For merge sections
instead of remembering just a live bit, we remember which offsets
were used.

This reduces the .rodata sections in chromium from 9648861 to 9477472
bytes.

llvm-svn: 267233
2016-04-22 22:09:35 +00:00
Peter Collingbourne dadcc17ead ELF: Move Visibility, IsUsedInRegularObj and MustBeInDynSym flags to Symbol.
These are properties of a symbol name, rather than a particular instance
of a symbol in an object file. We can simplify the code by collecting these
properties in Symbol.

The MustBeInDynSym flag has been renamed ExportDynamic, as its semantics
have been changed to be the same as those of --dynamic-list and
--export-dynamic-symbol, which do not cause hidden symbols to be exported.

Differential Revision: http://reviews.llvm.org/D19400

llvm-svn: 267183
2016-04-22 18:42:48 +00:00
Rui Ueyama 467dbdd030 Remove SymPair and instead use two DefinedRegulars instead.
I noticed that I was looking for the definition of SymPair when hacking
the Writer, only to find that it is just a pair of DefinedRegular symbols.
I don't think it provides more values than the cost of using brainpower
to memorize the type. I didn't roll back r266317, which introduced SymPair,
because the patch removes code repetitions. I ported that change to new
code.

llvm-svn: 267047
2016-04-21 20:50:15 +00:00
Rafael Espindola ae605c1b0c Start adding support for internalizing shared libraries.
llvm-svn: 267045
2016-04-21 20:35:25 +00:00
Rafael Espindola e26b50e71a Reduce templating. NFC.
llvm-svn: 267018
2016-04-21 17:37:11 +00:00
Rafael Espindola b312a740ae Delete the needsPlt target hook.
It can be made redundant with getRelExpr.

llvm-svn: 267012
2016-04-21 17:30:24 +00:00
Rafael Espindola 34b335bdf7 Don't recompute getRelExpr. NFC.
llvm-svn: 267005
2016-04-21 16:59:25 +00:00
Rafael Espindola 0c869a752e Moves needsPlt to Writer.cpp.
It was only used there.

llvm-svn: 267002
2016-04-21 16:57:32 +00:00
Simon Atanasyan ca58a8ff5b [ELF][MIPS] Create GOT entries for R_MIPS_REL32 dynamic relocations
MIPS ABI turns using of GOT and dynamic relocations inside out. While
regular ABI uses dynamic relocations to fill up GOT entries MIPS ABI
requires dynamic linker to fills up GOT entries using specially sorted
dynamic symbol table. This affects even dynamic relocations against
symbols which do not require GOT entries creation explicitly, i.e. do
not have any GOT-relocations. So if a preemptible symbol has a dynamic
relocation we anyway have to create a GOT entry for it.

If a non-preemptible symbol has a dynamic relocation against it, dynamic
linker takes it st_value, adds offset and writes down result of the
dynamic relocation. In case of preemptible symbol dynamic linker
performs symbol resolution, writes the symbol value to the GOT entry and
reads the GOT entry when it needs to perform a dynamic relocation.

Differential Revision: http://reviews.llvm.org/D18948

llvm-svn: 266921
2016-04-20 21:40:33 +00:00
Rui Ueyama 07320e4030 ELF: Template LinkerScript class.
Originally, linker scripts were basically an alternative way to specify
options to the command line options. But as we add more features to hanlde
symbols and sections, many member functions needed to be templated.
Now most the members are templated. It is probably time to template the
entire class.

Previously, LinkerScript is an executor of the linker script as well as
a storage of linker script configurations. This is not suitable to template
the class because when we are reading linker script files, we don't know
the ELF type yet, so we can't instantiate ELF-templated classes.

In this patch, I defined a new class, ScriptConfiguration, to store
linker script configurations. ScriptParser writes parse results to it,
and LinkerScript uses them.

Differential Revision: http://reviews.llvm.org/D19302

llvm-svn: 266908
2016-04-20 20:13:41 +00:00
Rafael Espindola c6b17bdc29 Delete refersToGotEntry.
It can be computed from the expression.

llvm-svn: 266890
2016-04-20 17:30:22 +00:00
Rafael Espindola 475dbf42e4 Simplify mips gp0 handling.
In all currently supported cases this is a nop.

llvm-svn: 266888
2016-04-20 17:20:49 +00:00
Rafael Espindola 2081dbcc7a Inline canRelaxTls.
It was always called in a position where the relocation type was already
known.

llvm-svn: 266880
2016-04-20 15:01:42 +00:00
Rafael Espindola f54413c18e Simplify canRelaxTls.
Check isTls in the called and pass a SymbolBody&.

llvm-svn: 266879
2016-04-20 14:52:18 +00:00
Rafael Espindola cc36a63f0b Move canRelaxTls to Writer.cpp. NFC.
llvm-svn: 266878
2016-04-20 14:41:55 +00:00
Rafael Espindola 6eda85ac1f Delete needsDynRelative.
It is now redundant. Writer.cpp can reason that 2 dynamic relocations
are needed: one to find the final got entry address and one to fill the
got entry.

llvm-svn: 266876
2016-04-20 14:36:24 +00:00
Rafael Espindola 58cd5db4ef Simplify mips got handling.
This avoids computing the address of a position in the got just to then
subtract got->getva().

llvm-svn: 266831
2016-04-19 22:46:03 +00:00
Rafael Espindola 5bf59728e2 Remove isGotRelative.
It is now redundant with the expression. While at it, handle both "X -
Got" and "Got - PC".

llvm-svn: 266607
2016-04-18 12:31:37 +00:00
Rafael Espindola 3f5d634c73 Have getRelExpr handle all cases on x86.
This requires adding a few more expression types, but is already a small
simplification. Having Writer.cpp know the exact expression will also
allow further simplifications.

llvm-svn: 266604
2016-04-18 12:07:13 +00:00
Rafael Espindola 99c224787b Delete the now redundant pointsToLocalDynamicGotEntry.
llvm-svn: 266584
2016-04-18 01:34:20 +00:00
Rafael Espindola df17277d72 Have getRelExpr return the final values for tls gd.
llvm-svn: 266583
2016-04-18 01:29:15 +00:00
Rafael Espindola c4d56970dc Change getRelExpr to return the final value for TLSLD. NFC.
llvm-svn: 266580
2016-04-18 00:28:57 +00:00
George Rimar 652852c5c0 Recommitted 266457 with fix:
* Do script driven layout only if SECTIONS section exist.

Initial commit message:

[ELF] - Implemented basic location counter support.

This patch implements location counter support. 
It also separates assign addresses for sections to assignAddressesScript() if it scipt exists.

Main testcase is test/ELF/linkerscript-locationcounter.s, It contains some work with location counter. It is basic now.
Implemented location counter assignment and '+' operations.

Patch by myself with LOTS of comments and design suggestions from Rui Ueyama.

Differential revision: http://reviews.llvm.org/D18499

llvm-svn: 266526
2016-04-16 10:10:32 +00:00
Rui Ueyama faac567e68 Revert r266457: "[ELF] - Implemented basic location counter support."
This reverts commit r266457 as it breaks "hello world" both on
Linux and FreeBSD.

llvm-svn: 266485
2016-04-15 22:39:27 +00:00
Rafael Espindola 5628ee7631 Simplify got handling.
Each getRelExpr is now expected to return the correct got expression
instead of having Writer patch it up with needsGot.

llvm-svn: 266466
2016-04-15 19:14:18 +00:00
George Rimar ea25877d4a [ELF] - Implemented basic location counter support.
This patch implements location counter support. 
It also separates assign addresses for sections to assignAddressesScript() if it scipt exists.

Main testcase is test/ELF/linkerscript-locationcounter.s, It contains some work with location counter. It is basic now.
Implemented location counter assignment and '+' operations.

Patch by myself with LOTS of comments and design suggestions from Rui Ueyama.

Differential revision: http://reviews.llvm.org/D18499

llvm-svn: 266457
2016-04-15 17:44:19 +00:00
Rafael Espindola 38c67a27fe Store a Symbol for EntrySym.
This makes it impossible to forget to call repl on the SymbolBody.

llvm-svn: 266432
2016-04-15 14:41:56 +00:00
Rafael Espindola 69a38060a8 Don't create relocations for absolute got entries.
llvm-svn: 266427
2016-04-15 12:44:43 +00:00
Rafael Espindola f8f6ad74a0 Don't create relocations for non preemptable absolute symbols.
llvm-svn: 266425
2016-04-15 12:22:22 +00:00
Rafael Espindola 3666025880 Two small related fixes.
* A hidden undefined is not preemptable.
* It is always zero, so we don't need a dynamic reloc for it.

llvm-svn: 266424
2016-04-15 11:57:07 +00:00
Simon Atanasyan 1ca263c890 [ELF][MIPS] Make R_MIPS_LO16 a relative relocation if it references _gp_disp symbol
The _gp_disp symbol designates offset between start of function and 'gp'
pointer into GOT. The following code is a typical MIPS function preamble
used to setup $gp register:

lui    $gp, %hi(_gp_disp)
addi   $gp, $gp, %lo(_gp_disp)

To calculate R_MIPS_HI16 / R_MIPS_LO16 relocations results we use
the following formulas:

%hi(_gp - P + A)
%lo(_gp - P + A + 4),
where _gp is a value of _gp symbol, A is addend, and P current address.

The R_MIPS_LO16 relocation references _gp_disp symbol is always the second
instruction. That is why we need four byte adjustments. The patch assigns
R_PC type for R_MIPS_LO16 relocation and adjusts its addend by 4. That fix
R_MIPS_LO16 calculation.

For details see p. 4-19 at ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf

Differential Revision: http://reviews.llvm.org/D19115

llvm-svn: 266368
2016-04-14 21:10:05 +00:00
Rafael Espindola 7f0b727235 Specialize the symbol table data structure a bit.
We never need to iterate over the K,V pairs, so we can avoid copying the
key as MapVector does.

This is a small speedup on most benchmarks.

llvm-svn: 266364
2016-04-14 20:42:43 +00:00
Rafael Espindola 3151d89595 Simplify handling of size relocations. NFC.
llvm-svn: 266355
2016-04-14 18:39:44 +00:00
George Rimar 5cfd306e00 Move variables closer to code scopes that uses them. NFC.
llvm-svn: 266340
2016-04-14 17:05:56 +00:00
Rafael Espindola 735bbaa1d9 Add missing typename.
llvm-svn: 266318
2016-04-14 14:40:38 +00:00
George Rimar 8bbff7ec85 [ELF] - Refactoring of end/edata/etext implementation.
Minor refactoring of how end/edata/etext symbols are handled.

Differential revision: http://reviews.llvm.org/D19109

llvm-svn: 266317
2016-04-14 14:37:59 +00:00
George Rimar 4c2ae3a171 Return back the zero parameter of aggregate initialization in OutputSectionFactory::lookup().
That was removed in r266304, but leads to warnings by Clang.
Thanks to Rafael Espíndola for pointing on that.

Though I think change was legal from point of C++.

llvm-svn: 266306
2016-04-14 14:24:23 +00:00
George Rimar d502f47726 Make OutputSectionFactory::lookup() inline. NFC.
Also I removed the last zero parameter of 
aggregate initialization as it is excessive here.

llvm-svn: 266304
2016-04-14 14:07:54 +00:00
George Rimar 2122168912 Removed excessive line. NFC.
llvm-svn: 266303
2016-04-14 13:56:28 +00:00
George Rimar 0fa18b8923 Reduce expression to single line. NFC.
llvm-svn: 266302
2016-04-14 13:47:04 +00:00