Commit Graph

236 Commits

Author SHA1 Message Date
Rui Ueyama bac1c3ce85 Pass StringRefs instead of StringMatcher because it's simpler.
llvm-svn: 287234
2016-11-17 16:48:53 +00:00
Rui Ueyama da805c4800 Use uint16_t instead of size_t for symbol version ID.
Because it is uint16_t in the ELF spec. Using size_t was confusing.

llvm-svn: 287198
2016-11-17 03:39:21 +00:00
Rui Ueyama 94bcfae26d Split scanVersionScript. NFC.
llvm-svn: 287191
2016-11-17 02:09:42 +00:00
Eugene Leviant afaa934304 [ELF] Add Section() to expression object
This allows making symbols containing ADDR(section) synthetic,
and defining synthetic symbols outside SECTIONS block.

Differential revision: https://reviews.llvm.org/D25441

llvm-svn: 287090
2016-11-16 09:49:39 +00:00
Rui Ueyama 8249214299 Refactor symbol version assignmnt code.
The code to handle symbol versions is getting tricky and hard to
understand, so it is probably time to simplify it. This patch does
the following.

 - Add `DemangledSyms` variable to SymbolTable so that we don't
   need to pass it around to findDemangled.
 - Define `initDemangledSyms` to initialize the variable lazily.
 - hasExternCpp is removed because we no longer have to initialize
   the map eagerly.
 - scanScriptVersion is split.
 - Comments are updated.

llvm-svn: 287002
2016-11-15 18:41:52 +00:00
George Rimar 463984d4bf [ELF] - Better diagnostic for relative relocation to an absolute value error.
Patch adds a filename to that error message.

I faced next error when debugged one of FreeBSD port:
error: relocation R_X86_64_PLT32 cannot refer to absolute symbol __tls_get_addr

error message was poor and this patch improves it to show the locations 
of symbol declaration and using.

Differential revision: https://reviews.llvm.org/D26508

llvm-svn: 286940
2016-11-15 08:07:14 +00:00
Rui Ueyama 1bdaf3e30c Remove an overloaded function to simplify.
This version of addRegular is almost identical to the other except
it lacked "size" parameter.

llvm-svn: 286416
2016-11-09 23:37:40 +00:00
Rafael Espindola e08e78df6d Make OutputSectionBase a class instead of class template.
The disadvantage is that we use uint64_t instad of uint32_t for some
value in 32 bit files. The advantage is a substantially simpler code,
faster builds and less code duplication.

llvm-svn: 286414
2016-11-09 23:23:45 +00:00
Eugene Leviant 825e538559 [ELF] Better error reporting for duplicate symbol
Differential revision: https://reviews.llvm.org/D26397

llvm-svn: 286244
2016-11-08 16:26:32 +00:00
Rui Ueyama 8c6a5aaf15 Create a vector containing all input sections.
Previously, we do this piece of code to iterate over all input sections.

  for (elf::ObjectFile<ELFT> *F : Symtab.getObjectFiles())
    for (InputSectionBase<ELFT> *S : F->getSections())

It turned out that this mechanisms doesn't work well with synthetic
input sections because synthetic input sections don't belong to any
input file.

This patch defines a vector that contains all input sections including
synthetic ones.

llvm-svn: 286051
2016-11-05 22:37:59 +00:00
Rui Ueyama f91282e1cf Add [<chars>] to the glob matcher to eliminate use of llvm::Regex.
Previously, it didn't support the character class, so we couldn't
eliminate the use fo llvm::Regex. Now that it is supported, we
can remove compileGlobPattern, which converts a glob pattern to
a regex.

This patch contains optimization for exact/prefix/suffix matches.

Differential Revision: https://reviews.llvm.org/D26284

llvm-svn: 285949
2016-11-03 17:57:38 +00:00
Rui Ueyama 07b83767a0 Use ArrayRef instead of const std::vector.
llvm-svn: 285776
2016-11-02 00:29:06 +00:00
Rui Ueyama 55518e7dd8 Consolidate BumpPtrAllocators.
Previously, we have a lot of BumpPtrAllocators, but all these
allocators virtually have the same lifetime because they are
not freed until the linker finishes its job. This patch aggregates
them into a single allocator.

Differential revision: https://reviews.llvm.org/D26042

llvm-svn: 285452
2016-10-28 20:57:25 +00:00
Rafael Espindola 093abab817 Don't create a dummy ELF to process a binary file.
Now that it is easy to create input section and symbols, this is
simple.

llvm-svn: 285322
2016-10-27 17:45:40 +00:00
Rafael Espindola 5ceeb60c6e Have on addRegular forward to another. NFC.
Another step in making it easier to create symbols without an ELf_Sym.

llvm-svn: 285241
2016-10-26 20:57:14 +00:00
Rui Ueyama 8fcc3afdd1 Move a helper function that doesn't depend on a class out of the class.
llvm-svn: 285220
2016-10-26 18:28:08 +00:00
Rafael Espindola 8b2c8536e5 Use a CachedHashString for comdats too.
We were already using it in the larger sets/maps. This provides about
1% speedup in linking xul and chromium.

llvm-svn: 284862
2016-10-21 19:49:42 +00:00
Justin Lebar 3c11e93831 Use CachedHashStringRef instead of CachedHash<StringRef>.
Summary:
This uses one less word on 64-bit platforms, so should be a strict
improvement.  This change also lets us get rid of llvm::CachedHash.

Reviewers: rafael, timshen

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25646

llvm-svn: 284502
2016-10-18 17:50:36 +00:00
Davide Italiano 786d8e33db [ELF/LTO] Switch to the new resolution-based API.
Differential Revision:  https://reviews.llvm.org/D24492

llvm-svn: 282656
2016-09-29 00:40:08 +00:00
George Rimar 31c25ae90a Recommit r281318 "[ELF] - Versionscript: support mangled symbols with the same name."
Previouly bot was failing:
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/413/steps/test-stage1-compiler/logs/stdio
Fixed possible segfault, so commit should bix the buildbot.

Initial commit message:

This is PR30312. Info from bug page:

Both of these symbols demangle to abc::abc():
_ZN3abcC1Ev
_ZN3abcC2Ev
(These would be abc's complete object constructor and base object constructor, respectively.)
however with "abc::abc()" in the version script only one of the two receives the symbol version.

Patch fixes that.
It uses testcase created by Ed Maste (D24306).

Differential revision: https://reviews.llvm.org/D24336

llvm-svn: 281605
2016-09-15 12:44:38 +00:00
Rui Ueyama 38dbd3eea9 Simplify InputFile ownership management.
Previously, all input files were owned by the symbol table.
Files were created at various places, such as the Driver, the lazy
symbols, or the bitcode compiler, and the ownership of new files
was transferred to the symbol table using std::unique_ptr.
All input files were then free'd when the symbol table is freed
which is on program exit.

I think we don't have to transfer ownership just to free all
instance at once on exit.

In this patch, all instances are automatically collected to a
vector and freed on exit. In this way, we no longer have to
use std::unique_ptr.

Differential Revision: https://reviews.llvm.org/D24493

llvm-svn: 281425
2016-09-14 00:05:51 +00:00
George Rimar 84ba4ae11d revert: [ELF] - Versionscript: support mangled symbols with the same name.
Something broked BBots:
281318 failed on step 9:
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/413

r281317 built step 9 green:
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/415

Initial revision commits were:
This is PR30312. Info from bug page:

Both of these symbols demangle to abc::abc():
_ZN3abcC1Ev
_ZN3abcC2Ev
(These would be abc's complete object constructor and base object constructor, respectively.)
however with "abc::abc()" in the version script only one of the two receives the symbol version.

Patch fixes that.
It uses testcase created by Ed Maste (D24306).

Differential revision: https://reviews.llvm.org/D24336

llvm-svn: 281411
2016-09-13 22:26:12 +00:00
Rui Ueyama ea26504c19 Split scanVersionScript. NFC.
llvm-svn: 281393
2016-09-13 20:51:30 +00:00
George Rimar e2051efcbe [ELF] - Versionscript: support mangled symbols with the same name.
This is PR30312. Info from bug page:

Both of these symbols demangle to abc::abc():
_ZN3abcC1Ev
_ZN3abcC2Ev
(These would be abc's complete object constructor and base object constructor, respectively.)
however with "abc::abc()" in the version script only one of the two receives the symbol version.

Patch fixes that.
It uses testcase created by Ed Maste (D24306).

Differential revision: https://reviews.llvm.org/D24336

llvm-svn: 281318
2016-09-13 10:45:39 +00:00
Michael J. Spencer 0cb8a70adc [ELF] Fix memory leak in BinaryFile handling.
llvm-svn: 281129
2016-09-10 01:42:43 +00:00
George Rimar c91930a17f [ELF] - Use std::regex instead of hand written logic in elf::globMatch()
Use std::regex instead of hand written matcher.

Patch based on code and ideas of Rui Ueyama.

Differential revision: https://reviews.llvm.org/D23829

llvm-svn: 280544
2016-09-02 21:17:20 +00:00
Rafael Espindola 0509876f3f Remove redundant argument. NFC.
llvm-svn: 280243
2016-08-31 13:49:23 +00:00
Rafael Espindola cceb92a075 Pass Binding instead of IsWeak to addBitcode.
We were computing the binding on both the caller and callee.

llvm-svn: 280156
2016-08-30 20:53:26 +00:00
Davide Italiano 35af5b3d21 [LTO] Fix the logic for dropping unnamed_addr.
Differential Revision:  https://reviews.llvm.org/D24037

llvm-svn: 280144
2016-08-30 20:15:03 +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
Rui Ueyama dace838138 Simplify symbol version handling.
r275711 for "speedng up symbol version handling" was committed
by misunderstanding; the benchmark number was measured with
a debug build. The number with a release build didn't actually change.
This patch removes false optimizations added in that patch.

llvm-svn: 276267
2016-07-21 13:13:21 +00:00
George Rimar b084125dbf [ELF] - Fixed integral constant overflow warning under MSVS 2015. NFC.
Under MSVS 2015 I observed integral constant overflow warning when aggregate initialization was used
to init the bit field. Patch fixes that.

llvm-svn: 276118
2016-07-20 14:26:48 +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 69c778c084 Implement almost-zero-cost --trace-symbol.
--trace-symbol is a command line option to watch a symbol.
Previosly, we looked up a hash table for a new symbol if the
option is given. Any code that looks up a hash table for each
symbol is expensive because the linker handles a lot of symbols.
In our design, we look up a hash table strictly only once
for a symbol, so --trace-symbol was an exception.

This patch improves efficiency of the option by merging the
hash table into the symbol table.

Instead of looking up a separate hash table with a string,
this patch sets `Traced` flag to symbols specified by --trace-symbol.
So, if you insert a symbol and get a symbol with `Traced` flag on,
you know that you need to print out a log message for the symbol.
This is nearly zero cost.

llvm-svn: 275716
2016-07-17 17:50:09 +00:00
Rui Ueyama 663b8c2769 Handle versioned symbols efficiently.
Versions can be assigned to symbols in two different ways.
One is the usual version scripts, and the other is special
symbol suffix '@'. If a symbol contains '@', the string after
that is considered to specify a version name.

Previously, we look for '@' for all symbols.

Anything that works on every symbol can be expensive because
the linker has to handle a lot of symbols. The search for '@'
was not an exception.

In this patch, I made two optimizations.

The first optimization is to handle '@' only when at least one
version is defined. If no versions are defined, no versions can
be assigned to any symbols, so it's waste of time to search for '@'.

The second optimization is to scan only suffixes of symbol names
instead of entire symbol names. Symbol names can be very long, but
symbol versions are usually short, so scanning entire symbol names
is waste of time, too.

There are some error cases which we no longer be able to detect
with this patch. I don't think it's a major drawback because they
are minor errors. Speed is more important.

This change improves LLD with debug info self-link time from
6.6993 seconds to 6.3426 seconds (or -5.3%).

Differential Revision: https://reviews.llvm.org/D22433

llvm-svn: 275711
2016-07-17 17:23:17 +00:00
George Rimar 50dcece2a0 Recommit r275257 "[ELF] - Implement extern "c++" version script tag"
BSD toolchain contains a bug:
https://sourceforge.net/p/elftoolchain/tickets/491/

In short demangler works differently, fix was to update the testcase.
It should fix the FreeBSD bot failture:
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/19432/steps/test_lld/logs/stdio

Original commit message was:
[ELF] - Implement extern "c++" version script tag

Patch implements 'extern' version script tag.
Currently only values in quotes(") are supported.

Matching of externs is performed in the same pass as exact match of globals.

Differential revision: http://reviews.llvm.org/D21930

llvm-svn: 275682
2016-07-16 12:26:39 +00:00
George Rimar dd64bb38bd Reverted r275257 "[ELF] - Implement extern "c++" version script tag"
It broke build bots:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/8204
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/19432

llvm-svn: 275258
2016-07-13 08:19:04 +00:00
George Rimar e05103ea11 [ELF] - Implement extern "c++" version script tag
Patch implements 'extern' version script tag.
Currently only values in quotes(") are supported.

Matching of externs is performed in the same pass as exact match of globals.

Differential revision: http://reviews.llvm.org/D21930

llvm-svn: 275257
2016-07-13 07:46:00 +00:00
Davide Italiano 8e1131dc46 [ELF] Support for wildcard in version scripts.
Example:

VERSION_1.0 {
  global: foo*;
  local: *; }

now correctly matches all the symbols which name starts with
`foo`.

Differential Revision:  http://reviews.llvm.org/D21732

llvm-svn: 274091
2016-06-29 02:46:51 +00:00
Rui Ueyama d60dae8a6a Implement --trace-symbol=symbol option.
Patch by Shridhar Joshi.

This option provides names of all the link time modules which define and
reference symbols requested by user. This helps to speed up application
development by detecting references causing undefined symbols.
It also helps in detecting symbols being resolved to wrong (unintended)
definitions in case of applications containing multiple definitions for
same symbols with different types, bindings.

Implements PR28226.

llvm-svn: 273536
2016-06-23 07:00:17 +00:00
Rafael Espindola cc70da39ff Internalize symbols in comdats.
We were dropping the CanOmitFromDynSym bit when creating undefined
symbols because of comdat.

llvm-svn: 272812
2016-06-15 17:56:10 +00:00
Rafael Espindola 65c65ce897 Don't include --start-lib/--end-lib files twice.
This should never happen with correct programs, but it is trivial
write a testcase where lld would crash or report duplicated
symbols. We now behave like when an archive is used and include the
file only once.

llvm-svn: 272724
2016-06-14 21:56:36 +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
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
George Rimar 22a95121b9 Removed dead code. NFC.
llvm-svn: 267685
2016-04-27 09:24:03 +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 66ac1d6152 ELF: Implement basic support for --version-script.
This patch only implements support for version scripts of the form:
  { [ global: symbol1; symbol2; [...]; symbolN; ] local: *; };
No wildcards are supported, other than for the local entry. Symbol versioning
is also not supported.

It works by introducing a new Symbol flag which tracks whether a symbol
appears in the global section of a version script.

This patch also simplifies the logic in SymbolBody::isPreemptible(), and
teaches it to handle the case where symbols with default visibility in DSOs
do not appear in the dynamic symbol table because of a version script.

Fixes PR27482.

Differential Revision: http://reviews.llvm.org/D19430

llvm-svn: 267208
2016-04-22 20:21:26 +00:00
Rafael Espindola 29af472cf6 Use llvm::CachedHash.
llvm-svn: 266982
2016-04-21 12:21:06 +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 c9157d35d9 Hash symbol names only once per global SymbolBody.
The DenseMap doesn't store hash results. This means that when it is
resized it has to recompute them.

This patch is a small hack that wraps the StringRef in a struct that
remembers the hash value. That way we can be sure it is only hashed
once.

llvm-svn: 266357
2016-04-14 19:17:16 +00:00
Adhemerval Zanella 9df0720766 ELF: Implement --dynamic-list
This patch implements the --dynamic-list option, which adds a list of
global symbol that either should not be bounded by default definition
when creating shared libraries, or add in dynamic symbol table in the
case of creating executables.

The patch modifies the ScriptParserBase class to use a list of Token
instead of StringRef, which contains information if the token is a
quoted or unquoted strings. It is used to use a faster search for
exact match symbol name.

The input file follow a similar format of linker script with some
simplifications (it does not have scope or node names). It leads
to a simplified parser define in DynamicList.{cpp,h}.

Different from ld/gold neither glob pattern nor mangled names
(extern 'C++') are currently supported.

llvm-svn: 266227
2016-04-13 18:51:11 +00:00
Peter Collingbourne f6e9b4ec24 ELF: Use hidden visibility for all DefinedSynthetic symbols.
This simplifies the code by allowing us to remove the visibility argument
to functions that create synthetic symbols.

The only functional change is that the visibility of the MIPS "_gp" symbol
is now hidden. Because this symbol is defined in every executable or DSO, it
would be difficult to observe a visibility change here.

Differential Revision: http://reviews.llvm.org/D19033

llvm-svn: 266208
2016-04-13 16:57:28 +00:00
Rui Ueyama f8baa66056 ELF: Implement --start-lib and --end-lib
start-lib and end-lib are options to link object files in the same
semantics as archive files. If an object is in start-lib and end-lib,
the object is linked only when the file is needed to resolve
undefined symbols. That means, if an object is in start-lib and end-lib,
it behaves as if it were in an archive file.

In this patch, I introduced a new notion, LazyObjectFile. That is
analogous to Archive file type, but that works for a single object
file instead of for an archive file.

http://reviews.llvm.org/D18814

llvm-svn: 265710
2016-04-07 19:24:51 +00:00
Rafael Espindola f47657301b Change the type hierarchy for undefined symbols.
We have to differentiate undefined symbols from bitcode and undefined
symbols from other sources.

Undefined symbols from bitcode should not inhibit the symbol being
internalized. Undefined symbols from other sources should.

llvm-svn: 265536
2016-04-06 13:22:41 +00:00
Rafael Espindola 28ed95f45e Revert unintentional change.
resolve can remain private.

Thanks to Rui for noticing it.

llvm-svn: 265336
2016-04-04 19:22:51 +00:00
Rafael Espindola ccfe3cb3d6 Don't store an Elf_Sym for most symbols.
Our symbol representation was redundant, and some times would get out of
sync. It had an Elf_Sym, but some fields were copied to SymbolBody.

Different parts of the code were checking the bits in SymbolBody and
others were checking Elf_Sym.

There are two general approaches to fix this:
* Copy the required information and don't store and Elf_Sym.
* Don't copy the information and always use the Elf_Smy.

The second way sounds tempting, but has a big problem: we would have to
template SymbolBody. I started doing it, but it requires templeting
*everything* and creates a bit chicken and egg problem at the driver
where we have to find ELFT before we can create an ArchiveFile for
example.

As much as possible I compared the test differences with what gold and
bfd produce to make sure they are still valid. In most cases we are just
adding hidden visibility to a local symbol, which is harmless.

In most tests this is a small speedup. The only slowdown was scylla
(1.006X). The largest speedup was clang with no --build-id, -O3 or
--gc-sections (i.e.: focus on the relocations): 1.019X.

llvm-svn: 265293
2016-04-04 14:04:16 +00:00
Reid Kleckner 4f88914c5b Remove unused fwd decl for LLVM IR stuff that lives in LTO now
llvm-svn: 264911
2016-03-30 20:15:41 +00:00
Reid Kleckner 20e24193f3 Remove declaration of SymbolTable::codegen, this method was deleted in r264091
llvm-svn: 264441
2016-03-25 18:20:33 +00:00
Davide Italiano 7cd8e65187 [LTO] Remove dead code.
llvm-svn: 264133
2016-03-23 02:45:53 +00:00
Rui Ueyama 259924869b ELF: Create LTO.{cpp,h} and move LTO-related code to that file.
The code for LTO has been growing, so now is probably a good time to
move it to its own file. SymbolTable.cpp is for symbol table, and
because compiling bitcode files are semantically not a part of
symbol table, this is I think a good thing to do.

http://reviews.llvm.org/D18370

llvm-svn: 264091
2016-03-22 20:52:10 +00:00
Rui Ueyama 9328b2cdde Use ELFT instead of ELFFile<ELFT>.
llvm-svn: 263510
2016-03-14 23:16:09 +00:00
George Rimar aa4dc20f09 [ELF] - Create _DYNAMIC symbol for dynamic output
lld needs to provide _DYNAMIC symbol when creating a shared library
both bfd and gold do that.

This should fix the https://llvm.org/bugs/show_bug.cgi?id=26732

Differential revision: http://reviews.llvm.org/D17607

llvm-svn: 262348
2016-03-01 16:23:13 +00:00
Rafael Espindola e0df00b91f Rename elf2 to elf.
llvm-svn: 262159
2016-02-28 00:25:54 +00:00
Rafael Espindola 18f0950783 Report duplicated symbols in bitcode.
llvm-svn: 262076
2016-02-26 21:49:38 +00:00
Rafael Espindola 9f77ef0c08 Add initial LTO support.
llvm-svn: 260726
2016-02-12 20:54:57 +00:00
Rafael Espindola 3a6a0a0109 Delete addIgnoredStrong.
It is not needed now that we resolve symbols is shared libraries
correctly.

llvm-svn: 258104
2016-01-19 00:05:54 +00:00
Simon Atanasyan 188558e5eb [ELF][MIPS] Prevent substitution of _gp_disp symbol
On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
start of function and gp pointer into GOT. To make seal with such symbol
we add new method addIgnoredStrong(). It adds ignored symbol with global
binding to prevent the symbol substitution. The addIgnored call is not
enough here because this call adds a weak symbol which might be
substituted by symbol from shared library.

Differential Revision: http://reviews.llvm.org/D16084

llvm-svn: 257449
2016-01-12 06:23:57 +00:00
Rui Ueyama 52c7c5fa3e Group members to match a comment. NFC.
llvm-svn: 257218
2016-01-08 22:20:00 +00:00
Rui Ueyama 131e0ffa10 Use shorter name. NFC.
llvm-svn: 257217
2016-01-08 22:17:42 +00:00
Rui Ueyama 683564ea63 Update comments.
llvm-svn: 257216
2016-01-08 22:14:15 +00:00
Rui Ueyama 8b4879aec0 Remove an empty constructor.
We used to have code in SymbolTable constructor to add entry symbols, etc.
That code has been moved to Driver. We can remove the constructor.

llvm-svn: 257214
2016-01-08 22:06:25 +00:00
Rui Ueyama 79c7373232 ELF: Consistently return SymbolBody * from SymbolTable::add functions.
For historical reasons, some add* functions for SymbolTable returns a
pointer to a SymbolBody, while some are not. This patch is to make them
consistently return a pointer to a newly added symbol.

llvm-svn: 257211
2016-01-08 21:53:28 +00:00
Rui Ueyama deb154001d ELF: Implement --wrap.
In this patch, all symbols are resolved normally and then wrap options
are applied. Renaming is implemented by mutating `Body` pointers of
Symbols. (As a result, Symtab.find(SymbolName)->getName() may return
a string that's different from SymbolName, but that is by design.
I designed the symbol and the symbol table to allow this kind of
operations.)

http://reviews.llvm.org/D15896

llvm-svn: 257075
2016-01-07 17:20:07 +00:00
Rui Ueyama 52d3b67c1d Rename Comdats -> ComdatGroups.
I usually prefer short names, but in this case the new descriptive
name should improve readability a bit.

llvm-svn: 256899
2016-01-06 02:06:33 +00:00
Rui Ueyama 2ef58a18af Remove SymbolTable::isUndefined.
Because it can be implemented outside of the symbol table.

llvm-svn: 256869
2016-01-05 20:35:16 +00:00
Rui Ueyama 2a65a49bcf Make findFile() a member function of SymbolTable to simplify. NFC.
llvm-svn: 256867
2016-01-05 20:01:29 +00:00
Rafael Espindola 21f7bd4ba1 Simplify memory management.
We no longer need an explicit delete or a polymorphic destructor.

llvm-svn: 256333
2015-12-23 14:35:51 +00:00
Rafael Espindola 5d7593bc59 Split Undefined and UndefinedElf.
I am working on adding LTO support to the new ELF lld.

In order to do that, it will be necessary to represent defined and
undefined symbols that are not from ELF files. One way to do it is to
change the symbol hierarchy to look like

Defined : SymbolBody
Undefined : SymbolBody

DefinedElf<ELFT> : Defined
UndefinedElf<ELFT> : Undefined

Another option would be to use bogus Elf_Sym, but I think that is
getting a bit too hackish.

This patch does the Undefined/UndefinedElf. Split. The next one
will do the Defined/DefinedElf split.

llvm-svn: 256289
2015-12-22 23:00:50 +00:00
Rafael Espindola 8a9f90e669 Refactor duplicated code. NFC.
llvm-svn: 256180
2015-12-21 19:09:19 +00:00
Rui Ueyama 6192c122f4 ELF: Move shouldUseRela to Writer.cpp.
The function was used only in Writer.cpp and did not depend on SymbolTable.
There is no reason to have that function in SymbolTable.cpp.

llvm-svn: 255850
2015-12-16 23:33:56 +00:00
Rui Ueyama 25b44c9b2b ELF: Make checkCompatibility a non-member function.
Because the function does not use any member of SymbolTable class.

llvm-svn: 255849
2015-12-16 23:31:22 +00:00
Rui Ueyama c5b9512958 ELF: Remove duplicate code.
We had duplicate code that were called before addMemberFile.
This patch makes them to be called at beginning of addMemberFile.

llvm-svn: 255845
2015-12-16 23:23:14 +00:00
Rui Ueyama 8957574549 ELF: Remove SymbolTable::addELFFile.
addELFFile was called only from addFile, and what it did was actually
just adding a file to the symbol table. There seems to be no reason
to separate the two.

llvm-svn: 255839
2015-12-16 22:59:13 +00:00
Rui Ueyama dd7d998919 ELF: Drop 'Sym' suffix from member function names for consistency.
Since the functions are members of SymbolTable class, it is obvious
that they are adding symbols.

llvm-svn: 255832
2015-12-16 22:31:14 +00:00
Rui Ueyama f09040120f ELF: Separate error message generation from call of error() or warning().
Previously reportConflict returned only when the third argument is false.
Now it always returns a value.

llvm-svn: 255829
2015-12-16 22:26:45 +00:00
Simon Atanasyan 09dae7c3e7 [ELF][MIPS] Handle R_MIPS_HI16/LO16 relocations against _gp_disp symbol
The `_gp_disp` is a magic symbol designates offset between start of
function and gp pointer into GOT. Only `R_MIPS_HI16` and `R_MIPS_LO16`
relocations are permitted with `_gp_disp`. The patch adds the `_gp_disp`
as an ignored symbol and adjusts symbol value before call the `relocateOne`
for `R_MIPS_HI16/LO16` relocations.

Differential Revision: http://reviews.llvm.org/D15480

llvm-svn: 255768
2015-12-16 14:45:09 +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
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
Rui Ueyama c7cc6ecf08 ELF2: Use ELFT to template OutputSections.
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
2015-10-15 22:27:29 +00:00
Rui Ueyama d9189ceb23 ELF2: Implement __start_SECNAME and __stop_SECNAME.
If a section name is valid as a C identifier (which is rare because of
the leading '.'), linkers are expected to define __start_<secname> and
__stop_<secname> symbols. They are at beginning and end of the section,
respectively. This is not requested by the ELF standard, but GNU ld and
gold provide this feature.

llvm-svn: 250432
2015-10-15 17:11:03 +00:00
Rafael Espindola ae81a7bf49 Use OutputSectionBase in a few cases where we don't need a OutputSection.
NFC. This is just preparation for adding a new OutputSection dedicated to
SHF_MERGE input sections.

llvm-svn: 250419
2015-10-15 15:29:53 +00:00
Rui Ueyama 93bfee5f70 ELF2: Avoid using "finalize" as a function name.
"finalize" does not give a hint about what that function is actually
going to do. This patch make it more specific by renaming scanShlibUndefined.
Also add a comment that we basically ignore undefined symbols in DSOs except
this function.

llvm-svn: 250191
2015-10-13 18:10:33 +00:00
Rui Ueyama f8432d97f3 ELF2: Fix BSD's __progname symbol issue.
BSD's DSO files have undefined symbol "__progname" which is defined
in crt1.o. On that system, both user programs and system shared
libraries depend on each other.

In general, we need to put symbols defined by user programs which are
referenced by shared libraries to user program's .dynsym.

http://reviews.llvm.org/D13637

llvm-svn: 250176
2015-10-13 16:34:14 +00:00
George Rimar 53b581c522 Removed undefined and unused member. NFC.
llvm-svn: 250163
2015-10-13 15:16:01 +00:00
Rui Ueyama 3d45179d56 ELF2: Split SymbolTable::addFile(). NFC.
llvm-svn: 250073
2015-10-12 18:03:21 +00:00
Rafael Espindola b9ca7bb6ab Delete getFirstELF.
llvm-svn: 250030
2015-10-12 11:52:31 +00:00
Rafael Espindola af70764aa1 Simplify the InputFile type hierarchy.
Now that the SymbolTable is templated, we don't need the ELFData class or
multiple inheritance.

llvm-svn: 250005
2015-10-12 01:55:32 +00:00
Rui Ueyama ff77768569 ELF2: Move Target and entry initialization from SymbolTable to Driver.
SymbolTable was not a right place for initialization. We had to do that
because Driver didn't know what type of ELF objects are being handled.
We taught Driver that, so we can now move this code to Driver.

llvm-svn: 249904
2015-10-09 21:12:40 +00:00
Rui Ueyama 3ce825ed26 ELF2: Make SymbolTable a template class.
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
2015-10-09 21:07:25 +00:00
Rafael Espindola 444576d4c4 Add support for comdats.
The implementation is a direct translation to c++ of the rules in the ELF spec.

llvm-svn: 249881
2015-10-09 19:25:07 +00:00
Igor Kudrin 65bddeaacf [ELF2] Check for TLS mismatch in symbol resolution.
The linker should generate an error if a TLS symbol is resolved
for a non-TLS reference and vice versa.

The patch addresses PR24244 (https://llvm.org/bugs/show_bug.cgi?id=24244)

Differential Revision: http://reviews.llvm.org/D13550

llvm-svn: 249817
2015-10-09 09:58:39 +00:00
Rui Ueyama e66e001c90 ELF2: Use the same name as COFF.
llvm-svn: 249635
2015-10-07 23:20:23 +00:00
Rui Ueyama e1f91529c8 ELF2: Rename dupError() -> reportConflict().
llvm-svn: 249622
2015-10-07 21:37:24 +00:00
Denis Protivensky 22220d5d5f [ELF2] Add --undefined option
Add symbol specified with -u as undefined which may cause additional
object files from archives to be linked into the resulting binary.

Differential Revision: http://reviews.llvm.org/D13345

llvm-svn: 249295
2015-10-05 09:43:57 +00:00
Rafael Espindola 5d41326751 Still define __init_array_(start|end) if there is no .init_array.
This matches the behavior of other linkers and seems necessary to link
in some older systems.

llvm-svn: 249077
2015-10-01 21:22:26 +00:00
Rafael Espindola 6a3b5ded8a Don't include shared libraries multiple times.
llvm-svn: 249061
2015-10-01 19:52:48 +00:00
Rafael Espindola 0e604f913a Add support for creating the symbols __init_array_start and __init_array_end.
llvm-svn: 248604
2015-09-25 18:56:53 +00:00
Rafael Espindola 5a5fdf7f73 Fix typo.
Thanks to Sean Silva for noticing.

llvm-svn: 248488
2015-09-24 12:58:44 +00:00
Rafael Espindola 1a49e58181 Print more information about duplicated symbols.
llvm-svn: 248380
2015-09-23 14:10:24 +00:00
Rafael Espindola 01205f79a4 Start adding target abstractions.
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
2015-09-22 18:19:46 +00:00
Rafael Espindola 40102eb27f Use a MapVector to output symbols in a deterministic order.
We used to sort the symbols at the very end, but we need to know the order
earlier so that we can create reference to them in the dynamic relocations.

Thanks to Igor Kudrin for pointing out the problem.

llvm-svn: 247911
2015-09-17 18:26:25 +00:00
Rafael Espindola 67a5da60ed Add support of Elf_Rel dynamic relocations.
llvm-svn: 247888
2015-09-17 14:02:10 +00:00
Rafael Espindola 4340aad144 Start adding support for creating shared libraries.
They are not fully functional yet, but this implements enough support for lld
itself to read them.

With that, delete the .so binary we were using for tests and start eating our
own dog food.

llvm-svn: 247487
2015-09-11 22:42:45 +00:00
Michael J. Spencer ac5f048e09 [lld][elf2] Address review comments.
llvm-svn: 247096
2015-09-08 22:51:46 +00:00
Michael J. Spencer 546c64c733 [lld][elf2] Fix hard coded entry address.
llvm-svn: 247089
2015-09-08 22:34:57 +00:00
Rafael Espindola 740fafe54d Start creating the .dynamic section.
For now it is always empty.

llvm-svn: 247056
2015-09-08 19:43:27 +00:00
Rafael Espindola 4f624b9581 Simplify reporting of undefined symbols.
llvm-svn: 247016
2015-09-08 14:32:29 +00:00
Michael J. Spencer 1b348a68e5 [elf2] Add basic archive file support.
llvm-svn: 246886
2015-09-04 22:28:10 +00:00
Rafael Espindola 824d1a975f Add a template helper to avoid multiple switches over the ELF kind. NFC.
llvm-svn: 246823
2015-09-04 00:09:43 +00:00
Rafael Espindola f98d6d84cd Start adding support for shared libraries.
This just adds the types and enough support to detect incompatibilities among
shared libraries and object files.

llvm-svn: 246797
2015-09-03 20:03:54 +00:00
Rafael Espindola 8aeb13fec1 Add a helper function for getting the first object file.
Also preparation for shared objects. It will become the first ELF file.

llvm-svn: 246796
2015-09-03 19:13:13 +00:00
Rafael Espindola 222edc66d6 Make ObjectFiles private. NFC.
Just preparation for adding support for shared libraries.

llvm-svn: 246793
2015-09-03 18:56:20 +00:00
Rafael Espindola ee1364f7f6 Don't leave unused strings in the string table.
llvm-svn: 246593
2015-09-01 21:47:21 +00:00
Rafael Espindola 5b3942f54a Don't include hidden or internal symbols in the symbol table.
llvm-svn: 246583
2015-09-01 20:36:51 +00:00
Rafael Espindola f7d45f0869 Delete SyntheticUndefined.
Now that resolved is templated anyway, we can use the regular Undefined.

llvm-svn: 246407
2015-08-31 01:46:20 +00:00
Rafael Espindola daa92a6193 Keep the largest common symbol.
This requires templating some functions over ELFT, but that opens other cleanup
opportunities for future patches.

llvm-svn: 246405
2015-08-31 01:16:19 +00:00
Rafael Espindola 4c3aa0f228 Delete unused forward declarations.
llvm-svn: 245055
2015-08-14 14:51:11 +00:00
Rafael Espindola beee25e484 Make these headers as being c++.
llvm-svn: 245050
2015-08-14 14:12:54 +00:00
Rafael Espindola 62b81b875a Start populating the symbol table.
With this patch only the name is set. I will set the other fields shortly.

For now the table doesn't include local symbols. This is equivalent to using
--discard-all with gnu ld. This is OK for now since the symbols are not
needed for execution and for testing symbol resolution we only need the
global symbols.

llvm-svn: 245044
2015-08-14 13:07:05 +00:00
Rafael Espindola 2ffdd4d0e5 The SymbolTable doesn't need to be a template.
It was already using just code that is common to all object files.

llvm-svn: 243985
2015-08-04 14:29:01 +00:00
Rafael Espindola b89951457d Remove SymbolTable::getChunks.
When we were using a std::sort over all the chunks we needed to put them in a
single storage.

Now that we just iterate over them and use a map to find the output section,
we can avoid allocating the temporary storage.

llvm-svn: 243980
2015-08-04 13:39:30 +00:00
Rui Ueyama b4731a5847 ELF2: Use DenseMap instead of std::map for a symbol table.
We use DenseMap for COFF too.

llvm-svn: 243534
2015-07-29 16:30:40 +00:00
Michael J. Spencer 84487f1174 [ELF2] Add a new ELF linker based on the new PE/COFF linker.
Differential Revision: http://reviews.llvm.org/D11188

llvm-svn: 243161
2015-07-24 21:03:07 +00:00
Michael J. Spencer bae540e945 Revert ELF port. Posting to mailing list.
llvm-svn: 242118
2015-07-14 04:49:48 +00:00
Michael J. Spencer 8a4145411f Initial ELF port.
This is a direct port of the new PE/COFF linker to ELF.

It can take a single object file and generate a valid executable that executes at the first byte in the text section.

llvm-svn: 242088
2015-07-13 23:48:06 +00:00