Commit Graph

336 Commits

Author SHA1 Message Date
Rafael Espindola ab0cce5f1f Replace SharedSymbols with Defined when creating copy relocations.
This is slightly simpler to read IMHO. Now if a symbol has a position
in the file, it is Defined.

The main motivation is that with this a SharedSymbol doesn't need a
section, which reduces the size of SymbolUnion.

With this the peak allocation when linking chromium goes from 568.1 to
564.2 MB.

llvm-svn: 330966
2018-04-26 17:58:58 +00:00
Rafael Espindola f4a9d56a9a Delete GotPltIndex.
It was always an offset of PltIndex.

This doesn't reduce the size of the structures, but makes it easier to
do so in a followup patch.

llvm-svn: 330953
2018-04-26 16:09:30 +00:00
Rui Ueyama 5fcebff485 Remove unused features from StringRefZ and move it to Symbols.h.
Differential Revision: https://reviews.llvm.org/D46087

llvm-svn: 330879
2018-04-25 22:34:21 +00:00
Rafael Espindola 1eeb26293d Pack symbols a bit more.
Before this patch:

Symbol 56
Defined 80
Undefined 56
SharedSymbol 88
LazyArchive 72
LazyObject 56

With this patch

Symbol 48
Defined 72
Undefined 48
SharedSymbol 80
LazyArchive 64
LazyObject 48

The result is that peak allocation when linking chromium (according to
heaptrack) goes from 578 to 568 MB.

llvm-svn: 330874
2018-04-25 21:44:37 +00:00
Rafael Espindola 047f857642 Also demote lazy symbols.
This is not a big simplification right now, but the special cases for
lazy symbols have been a common source of bugs in the past.

llvm-svn: 330869
2018-04-25 20:46:08 +00:00
George Rimar 19f9b814dd [ELF] - Refactor lazy symbol duplicated code.
Our code for LazyObject and LazyArchive duplicates.

This patch extracts the common part to remove
the duplication.

Differential revision: https://reviews.llvm.org/D45516

llvm-svn: 330701
2018-04-24 09:41:56 +00:00
Rafael Espindola aded409325 Simplify getOffset for synthetic sections.
We had a single symbol using -1 with a synthetic section. It is
simpler to just update its value.

This is not a big will by itself, but will allow having a simple
getOffset for InputSeciton.

llvm-svn: 330340
2018-04-19 16:54:30 +00:00
Michael J. Spencer b842725c1d [ELF] Add profile guided section layout
This adds profile guided layout using the Call-Chain Clustering (C³) heuristic
from https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf .

RFC: [llvm-dev] [RFC] Profile guided section layout
     http://lists.llvm.org/pipermail/llvm-dev/2017-June/114178.html

Pass `--call-graph-ordering-file <file>` to read a call graph profile where each
line has the format:

    <from symbol> <to symbol> <call count>

Differential Revision: https://reviews.llvm.org/D36351

llvm-svn: 330234
2018-04-17 23:30:05 +00:00
Sam Clegg d11b6edfc8 Remove references to old SymbolBody class
Differential Revision: https://reviews.llvm.org/D45400

llvm-svn: 329846
2018-04-11 19:52:53 +00:00
George Rimar 1ef746ba21 [ELF] - Eliminate Lazy class.
Patch removes Lazy class which
is just an excessive layer.

Differential revision: https://reviews.llvm.org/D45083

llvm-svn: 329086
2018-04-03 17:16:52 +00:00
George Rimar 624e163f53 [ELF] - Remove dead declaration. NFC.
llvm-svn: 329058
2018-04-03 10:40:39 +00:00
Rui Ueyama 7d6131a898 Inline two trivial functions that are called only once. NFC.
llvm-svn: 329034
2018-04-02 23:58:50 +00:00
Rafael Espindola e3a6062844 Simplify. NFC.
Since r321982 we don't set VersionId in scanShlibUndefined, which
makes InVersionScript redundant.

llvm-svn: 326641
2018-03-03 02:13:50 +00:00
Rui Ueyama ee17371897 Merge {COFF,ELF}/Strings.cpp to Common/Strings.cpp.
This should resolve the issue that lld build fails in some hosts
that uses case-insensitive file system.

Differential Revision: https://reviews.llvm.org/D43788

llvm-svn: 326339
2018-02-28 17:38:19 +00:00
Fangrui Song ffac3ed341 [ELF] Fix IsPreemptible comment and typo. NFC
llvm-svn: 325963
2018-02-23 21:57:49 +00:00
Fangrui Song 9cd5df0e15 [ELF] Add comment for preemptible and fix typo. NFC
Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D43642

llvm-svn: 325855
2018-02-23 02:05:48 +00:00
Sam Clegg 3141ddc58d Consistent (non) use of empty lines in include blocks
The profailing style in lld seem to be to not include such empty lines.
Clang-tidy/clang-format seem to handle this just fine.

Differential Revision: https://reviews.llvm.org/D43528

llvm-svn: 325629
2018-02-20 21:53:18 +00:00
Rui Ueyama 38781a59f6 Revert r325158: Convert an assert to a static_assert. NFC.
This reverts commit r325158 because it broke GCC builds.

llvm-svn: 325183
2018-02-14 22:43:43 +00:00
Sam Clegg ab31b7759d Convert an assert to a static_assert. NFC.
Differential Revision: https://reviews.llvm.org/D43305

llvm-svn: 325158
2018-02-14 19:28:46 +00:00
Sam Clegg 38f52b2eb8 Check that Symbol types are trivially destructible
This adds an extra level of static safety to our use of placement
new to allocate Symbol types.  It prevents the accidental addition
on a non-trivially-destructible member that could allocate and
leak memory.

From the spec: Storage occupied by trivially destructible objects
may be reused without calling the destructor.

Differential Revision: https://reviews.llvm.org/D43244

llvm-svn: 325025
2018-02-13 17:32:31 +00:00
Rafael Espindola 62003fbb02 Inline foot gun into only valid use.
Symbol had both Visibility and getVisibility() and they had different
meanings. That is just too easy to get wrong.

getVisibility() would compute the visibility of a particular symbol
(foo in bar.o), and Visibility stores the computed value we will put
in the output.

There is only one case when we want what getVisibility() provides, so
inline it.

llvm-svn: 322590
2018-01-16 19:28:28 +00:00
George Rimar d70da0e55f [ELF] - Fix mistype in comment. NFC.
llvm-svn: 321403
2017-12-23 16:34:58 +00:00
Rafael Espindola b9a18fd0a2 Define isUndefWeak inline.
This small function was showing up in the profile. Defining it inline
gives about 0.3% speedup.

llvm-svn: 321317
2017-12-21 22:26:44 +00:00
Rafael Espindola efb483f63a Pass a InputFile reference to the Lazy constructor. NFC.
llvm-svn: 321199
2017-12-20 18:01:32 +00:00
Rafael Espindola 8276f1bda6 Use a reference to a file in the LazyArchive symbol.
It is never null.

llvm-svn: 321198
2017-12-20 17:59:43 +00:00
Rafael Espindola 2e5c71eadc LazyObject's file is never null, use a reference.
llvm-svn: 321196
2017-12-20 17:52:36 +00:00
Rafael Espindola a32ddc4639 Use a reference for the shared symbol file.
Every shared symbol has a file, so we can use a reference.

llvm-svn: 321187
2017-12-20 16:28:19 +00:00
Rafael Espindola 8f619ab826 Compact symbols from 96 to 88 bytes.
By using an index instead of a pointer for verdef we can put the index
next to the alignment field. This uses the otherwise wasted area and
reduces the shared symbol size.

By itself the performance change of this is in the noise, but I have a
followup patch to remove another 8 bytes that improves performance
when combined with this.

llvm-svn: 320449
2017-12-12 01:45:49 +00:00
Rafael Espindola dfebd3601d Use Symbol::File directly.
We are already paying the cost of storing a InputFile in every
Symbol, so use it uniformly.

llvm-svn: 319378
2017-11-29 22:47:35 +00:00
Rafael Espindola b262cbe6b7 Replace copyFrom with memcpy.
It was only used for --wrap and I don't think the fields with special
treatment had a meaningful impact on that feature.

llvm-svn: 319265
2017-11-29 00:31:39 +00:00
Rafael Espindola 1d4b3023dc Bring back r319008.
This includes a fix to mark copy reloc aliases as used.

Original message:

[ELF] Do not keep symbols if they referenced only from discarded sections.

This patch also ensures that in case of "--as-needed" is used,
DT_NEEDED entries are not created if they are required only by
these eliminated symbols.

llvm-svn: 319215
2017-11-28 20:17:58 +00:00
Igor Kudrin a46522f369 Revert r319008, "[ELF] Do not keep symbols if they referenced only from discarded sections."
and r319051, "Add a missing test."

r319008 broke the LTO bots;
r319051 depends on changes in r319008.

llvm-svn: 319154
2017-11-28 08:39:40 +00:00
Rafael Espindola 9e3381e8dc Store the real binding of shared symbols.
Currently we mark every shared symbol as STB_WEAK.

That is a hack to make it easy to decide when a .so is needed or not
because of a reference to a given symbol.

That hack leaks when we create copy relocations as shown by the update
to relocation-copy-alias.s.

This patch stores the original binding when we first read a shared
symbol. We still have to update the binding to weak if we see a weak
undef, but I find the logic easier to read where it is now.

llvm-svn: 319127
2017-11-28 01:04:51 +00:00
Igor Kudrin 40007586fc [ELF] Do not keep symbols if they referenced only from discarded sections.
This patch also ensures that in case of "--as-needed" is used,
DT_NEEDED entries are not created if they are required only by
these eliminated symbols.

Differential Revision: https://reviews.llvm.org/D38790

llvm-svn: 319008
2017-11-27 05:51:10 +00:00
Rafael Espindola f8e405db46 Delete dead code.
The parent constructor is already setting the binding.

llvm-svn: 318962
2017-11-24 19:06:14 +00:00
Rafael Espindola bec3765bea Remove IsLocal.
Since we always have Binding in the current symbol design IsLocal is
redundant.

llvm-svn: 318497
2017-11-17 01:37:50 +00:00
Rafael Espindola 03e4ae42d5 Delete unused constructor.
llvm-svn: 317625
2017-11-07 22:30:53 +00:00
Rui Ueyama 989b1fcb01 Remove dead code.
llvm-svn: 317530
2017-11-07 00:26:04 +00:00
Rui Ueyama 7957b08e87 Move MIPS-specific code from Symbols.cpp to MIPS.cpp.
We have a lot of "if (MIPS)" conditions in lld because the MIPS' ABI
is different at various places than other arch's ABIs at where it
don't have to be different, but we at least want to reduce MIPS-ness
from the regular classes.

llvm-svn: 317525
2017-11-07 00:04:22 +00:00
Peter Collingbourne b472aa0268 ELF: Remove function Symbol::isInCurrentOutput().
This function is now equivalent to isDefined().

llvm-svn: 317449
2017-11-06 04:39:07 +00:00
Peter Collingbourne e9a9e0a1e7 ELF: Merge DefinedRegular and Defined.
Now that DefinedRegular is the only remaining derived class of
Defined, we can merge the two classes.

Differential Revision: https://reviews.llvm.org/D39667

llvm-svn: 317448
2017-11-06 04:35:31 +00:00
Peter Collingbourne 6c55a70838 ELF: Remove DefinedCommon.
Common symbols are now represented with a DefinedRegular that points
to a BssSection, even during symbol resolution.

Differential Revision: https://reviews.llvm.org/D39666

llvm-svn: 317447
2017-11-06 04:33:58 +00:00
Rui Ueyama 32665f702e Do not consider Shared symbols as defined symbols.
I don't remember why I made shared symbols one type of defined symbols.
Shared symbols aren't undefined, so it could be considered defined, but
categorizing three symbols as:

 - defined
   - really defined
   - shared
 - undefined

is not as intuitive as

 - defined
 - shared
 - undefined

to me. So, in this patch, I made a change to stop handling shared
symbols as defined symbols.

Surprisingly, I didn't have to update any tests for this change.

Differential Revision: https://reviews.llvm.org/D39394

llvm-svn: 317446
2017-11-06 04:13:24 +00:00
Rui Ueyama f483da0038 Rename replaceBody -> replaceSymbol.
llvm-svn: 317383
2017-11-03 22:48:47 +00:00
Rui Ueyama f52496e1e0 Rename SymbolBody -> Symbol
Now that we have only SymbolBody as the symbol class. So, "SymbolBody"
is a bit strange name now. This is a mechanical change generated by

  perl -i -pe s/SymbolBody/Symbol/g $(git grep -l SymbolBody lld/ELF lld/COFF)

nd clang-format-diff.

Differential Revision: https://reviews.llvm.org/D39459

llvm-svn: 317370
2017-11-03 21:21:47 +00:00
Rui Ueyama f1f00841d9 Merge SymbolBody and Symbol into one class, SymbolBody.
SymbolBody and Symbol were separated classes due to a historical reason.
Symbol used to be a pointer to a SymbolBody, and the relationship
between Symbol and SymbolBody was n:1.

r2681780 changed that. Since that patch, SymbolBody and Symbol are
allocated next to each other to improve memory locality, and they have
1:1 relationship now. So, the separation of Symbol and SymbolBody no
longer makes sense.

This patch merges them into one class. In order to avoid updating too
many places, I chose SymbolBody as a unified name. I'll rename it Symbol
in a follow-up patch.

Differential Revision: https://reviews.llvm.org/D39406

llvm-svn: 317006
2017-10-31 16:07:41 +00:00
Rafael Espindola 458173e802 Use 64 bits for the shared symbol size again.
We might want to drop support for such large symbols, but that should
be an explicit decision with a testcase.

llvm-svn: 316931
2017-10-30 17:43:16 +00:00
Rui Ueyama bd730e3ca7 Reduce sizeof(Symbol) from 104 bytes to 88 bytes.
Finding aliases for shared symbols doesn't need st_shndx because
we can just compare st_value.

llvm-svn: 316848
2017-10-28 22:18:17 +00:00
Rui Ueyama 7f9694a42d Pass symbol attributes instead of ElfSym to Shared symbol ctor.
This change allows us to use less templates for Shared symbol and
the functions that deals with shared symbols.

llvm-svn: 316841
2017-10-28 20:15:56 +00:00
Rui Ueyama da524d021a Remove unnecessary namespace specifiers.
llvm-svn: 316812
2017-10-27 23:29:58 +00:00