Commit Graph

655 Commits

Author SHA1 Message Date
Rui Ueyama bee192f6b0 Simplify. NFC.
llvm-svn: 336686
2018-07-10 15:15:56 +00:00
Rui Ueyama 3467fac091 Rename a variable for consistency. NFC.
llvm-svn: 336674
2018-07-10 14:03:39 +00:00
Rui Ueyama 7f112ea26d Reduce memory usage when creating .gdb_index. NFC.
.gdb_index sections can be very large. When you are compiling
multi-gibibyte executables, they can be larger than 1 GiB. The previous
implementation of .gdb_index seems to consume too much memory.

This patch reduces memory consumption by eliminating temporary objects.
In one experiment, memory consumption of GdbIndexSection class is
reduced from 962 MiB to 228 MiB when creating a .gdb_index of 1350 GiB.

Differential Revision: https://reviews.llvm.org/D49094

llvm-svn: 336672
2018-07-10 13:49:13 +00:00
Rui Ueyama 2a3036fb1d Report an error for an extremely large .gdb_index section.
I believe the only way to test this functionality is to create extremely
large object files and attempt to create a .gdb_index that is greater
than 4 GiB. But I think that's too much for most environments and buildbots,
so I'm commiting this without a test that actually triggers the new
error condition.

llvm-svn: 336631
2018-07-10 01:22:25 +00:00
Rui Ueyama a9e169edff Fix a bug for packed relocations.
Previously, we didn't create multiple consecutive bitmaps.
Added a test to catch this bug too.

Differential Revision: https://reviews.llvm.org/D49107

llvm-svn: 336620
2018-07-09 23:54:24 +00:00
Rui Ueyama 703c872a4a Simplify RelrSection<ELFT>::updateAllocSize.
This patch also speeds it up by making some constants compile-time
constants. Other than that, NFC.

Differential Revision: https://reviews.llvm.org/D49101

llvm-svn: 336614
2018-07-09 22:29:57 +00:00
Rui Ueyama 11479daf2f lld: add experimental support for SHT_RELR sections.
Patch by Rahul Chaudhry!

This change adds experimental support for SHT_RELR sections, proposed
here: https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg

Pass '--pack-dyn-relocs=relr' to enable generation of SHT_RELR section
and DT_RELR, DT_RELRSZ, and DT_RELRENT dynamic tags.

Definitions for the new ELF section type and dynamic array tags, as well
as the encoding used in the new section are all under discussion and are
subject to change. Use with caution!

Pass '--use-android-relr-tags' with '--pack-dyn-relocs=relr' to use
SHT_ANDROID_RELR section type instead of SHT_RELR, as well as
DT_ANDROID_RELR* dynamic tags instead of DT_RELR*. The generated
section contents are identical.

'--pack-dyn-relocs=android+relr --use-android-relr-tags' enables both
'--pack-dyn-relocs=android' and '--pack-dyn-relocs=relr': lld will
encode the relative relocations in a SHT_ANDROID_RELR section, and pack
the rest of the dynamic relocations in a SHT_ANDROID_REL(A) section.

Differential Revision: https://reviews.llvm.org/D48247

llvm-svn: 336594
2018-07-09 20:08:55 +00:00
Zaara Syeda de54f584cc [PPC64] Add support for R_PPC64_GOT_DTPREL16* relocations
The local dynamic TLS access on PPC64 ELF v2 ABI uses R_PPC64_GOT_DTPREL16*
relocations when a TLS variables falls outside 2 GB of the thread storage
block. This patch adds support for these relocations by adding a new RelExpr
called R_TLSLD_GOT_OFF which emits a got entry for the TLS variable relative
to the dynamic thread pointer using the relocation R_PPC64_DTPREL64. It then
evaluates the R_PPC64_GOT_DTPREL16* relocations as the got offset for the
R_PPC64_DTPREL64 got entries.

Differential Revision: https://reviews.llvm.org/D48484

llvm-svn: 335732
2018-06-27 13:55:41 +00:00
George Rimar 8f53b6d71e [ELF] - Change the way of sorting local symbols.
rLLD329787 added the stable sorting to SymbolTableBaseSection::postThunkContents.

I profiled the Mozilla (response-O0.txt) from lld-speed-test package and found
std::stable_sort is showing up in profile results and consuming the 3.1% of the total
CPU time in the RelWithDebug build. Total time of postThunkContents is 3.54%, 238ms.

This change reduces postTimeContents time to 50ms, making it to take 0.73% of Total CPU time.

So, instead of sorting the local part I suggest to just rebuild it.
That is what this patch does.

Differential revision: https://reviews.llvm.org/D45519

llvm-svn: 335583
2018-06-26 08:50:09 +00:00
Simon Atanasyan 6d163c5feb [ELF][MIPS] Fill a primary-GOT as much as possible
While building a Global Offset Table try to fill the primary GOT as much
as possible because the primary GOT can be accessed in the most
effective way. If it is not possible, try to fill the last GOT in the
multi-GOT list, and finally create a new GOT if both attempts failed.

llvm-svn: 335140
2018-06-20 15:58:48 +00:00
Fangrui Song bd3684f25b [ELF] Support -z initfirst
Summary:
glibc uses this option to link libpthread.so

glibc/nptl/Makefile:
LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst

Reviewers: ruiu, echristo, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48329

llvm-svn: 335090
2018-06-20 02:06:01 +00:00
Simon Atanasyan 9655fe6322 [ELF][MIPS] Fix stable_sort predicate to satisfy strict-ordering requirement. NFC
Fix for PR37785.

llvm-svn: 334851
2018-06-15 18:15:26 +00:00
Simon Atanasyan 9629d7897d [ELF][MIPS] Replace calls to MapVector::find by MapVector::lookup. NFC
llvm-svn: 334705
2018-06-14 11:53:31 +00:00
Alexander Richardson 127176e59e [ELF][MIPS] Fix TLS GOT entries for local symbols in shared libraries
Summary:
Previously LLD would not add any dynamic relocations and write a module
index of 1 which is not correct for the shared library case.
This can happen when a thread-local global variable is marked as local with
a version script. With this change I am now able to link all of the FreeBSD
base system for MIPS64 with LLD.

Differential Revision: https://reviews.llvm.org/D48002

llvm-svn: 334483
2018-06-12 08:00:38 +00:00
Simon Atanasyan 00d8843fa3 [ELF] Pass a pointer to InputFile to the getRelocTargetVA to escape dereferencing of nullptr. NFC
llvm-svn: 334392
2018-06-11 08:37:19 +00:00
Simon Atanasyan ed9ee69ccf [ELF][MIPS] Multi-GOT implementation
Almost all entries inside MIPS GOT are referenced by signed 16-bit
index. Zero entry lies approximately in the middle of the GOT. So the
total number of GOT entries cannot exceed ~16384 for 32-bit architecture
and ~8192 for 64-bit architecture. This limitation makes impossible to
link rather large application like for example LLVM+Clang. There are two
workaround for this problem. The first one is using the -mxgot
compiler's flag. It enables using a 32-bit index to access GOT entries.
But each access requires two assembly instructions two load GOT entry
index to a register. Another workaround is multi-GOT. This patch
implements it.

Here is a brief description of multi-GOT for detailed one see the
following link https://dmz-portal.mips.com/wiki/MIPS_Multi_GOT.

If the sum of local, global and tls entries is less than 64K only single
got is enough. Otherwise, multi-got is created. Series of primary and
multiple secondary GOTs have the following layout:
```
- Primary GOT
    Header
    Local entries
    Global entries
    Relocation only entries
    TLS entries

- Secondary GOT
    Local entries
    Global entries
    TLS entries
...
```

All GOT entries required by relocations from a single input file
entirely belong to either primary or one of secondary GOTs. To reference
GOT entries each GOT has its own _gp value points to the "middle" of the
GOT. In the code this value loaded to the register which is used for GOT
access.

MIPS 32 function's prologue:
```
lui     v0,0x0
0: R_MIPS_HI16  _gp_disp
addiu   v0,v0,0
4: R_MIPS_LO16  _gp_disp
```

MIPS 64 function's prologue:
```
lui     at,0x0
14: R_MIPS_GPREL16  main
```

Dynamic linker does not know anything about secondary GOTs and cannot
use a regular MIPS mechanism for GOT entries initialization. So we have
to use an approach accepted by other architectures and create dynamic
relocations R_MIPS_REL32 to initialize global entries (and local in case
of PIC code) in secondary GOTs. But ironically MIPS dynamic linker
requires GOT entries and correspondingly ordered dynamic symbol table
entries to deal with dynamic relocations. To handle this problem
relocation-only section in the primary GOT contains entries for all
symbols referenced in global parts of secondary GOTs. Although the sum
of local and normal global entries of the primary got should be less
than 64K, the size of the primary got (including relocation-only entries
can be greater than 64K, because parts of the primary got that overflow
the 64K limit are used only by the dynamic linker at dynamic link-time
and not by 16-bit gp-relative addressing at run-time.

The patch affects common LLD code in the following places:

- Added new hidden -mips-got-size flag. This flag required to set low
maximum size of a single GOT to be able to test the implementation using
small test cases.

- Added InputFile argument to the getRelocTargetVA function. The same
symbol referenced by GOT relocation from different input file might be
allocated in different GOT. So result of relocation depends on the file.

- Added new ctor to the DynamicReloc class. This constructor records
settings of dynamic relocation which used to adjust address of 64kb page
lies inside a specific output section.

With the patch LLD is able to link all LLVM+Clang+LLD applications and
libraries for MIPS 32/64 targets.

Differential revision: https://reviews.llvm.org/D31528

llvm-svn: 334390
2018-06-11 07:24:31 +00:00
Sean Fertile 49914cc807 [PPC64] Add lazy symbol resolution stubs.
Adds support for .glink resolver stubs from the example implementation in the V2
ABI (Section 4.2.5.3. Procedure Linkage Table). The stubs are written to the
PltSection, and the sections are renamed to match the PPC64 ABI:
    .got.plt --> .plt    Type = SHT_NOBITS
    .plt     --> .glink

And adds the DT_PPC64_GLINK dynamic tag to the dynamic section when the plt is
not empty.

Differential Revision: https://reviews.llvm.org/D45642

llvm-svn: 331840
2018-05-09 02:07:53 +00:00
Simon Atanasyan 0560050668 [ELF][MIPS] Fix calculation of GP relative relocations in case of relocatable output
Some MIPS relocations depend on "gp" value. By default, this value has
0x7ff0 offset from a .got section. But relocatable files produced by a
compiler or a linker might redefine this default value and we have to
use it for a calculation of the relocation result. When we generate EXE
or DSO it's trivial. Generating a relocatable output is more difficult
case because the linker does calculate relocations in this case and
cannot store individual "gp" values used by each input object file.
As a workaround we add the "gp" value to the relocation addend.

This fixes https://llvm.org/pr31149

Differential revision: https://reviews.llvm.org/D45972

llvm-svn: 331772
2018-05-08 15:34:06 +00:00
Fangrui Song 95851515d7 Add a CIE with length 0 unconditionally.
Summary: This is not technically required, but glibc unwind-dw2-fde.c classify_object_over_fdes expects there is a CIE record length 0 as a terminator.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D46566

llvm-svn: 331708
2018-05-08 01:19:16 +00:00
Simon Atanasyan 86a1219d30 [ELF][MIPS] Add STO_MIPS_MICROMIPS flag to symbols point to microMIPS PLT records
llvm-svn: 331554
2018-05-04 20:48:47 +00:00
Rafael Espindola bd4d2acb11 Don't create a temporary DenseMap for each input .eh_frame.
These maps are small, but we are creating an destroying one for each
input .eh_frame.

This patch reduces the total memory allocation from 765.54MB to
749.19MB. The peak is still the same: 563.7MB.

llvm-svn: 331075
2018-04-27 20:19:28 +00:00
Rafael Espindola f1652d4c60 Split .eh_frame sections in parellel.
We can now split them in the same spot we split merge sections.

llvm-svn: 331064
2018-04-27 18:17:36 +00:00
Rafael Espindola 9bf1006278 Split merge sections early.
Now that getSectionPiece is fast (uses a hash) it is probably OK to
split merge sections early.

The reason I want to do this is to split eh_frame sections in the same
place.

This does mean that we have to decompress early. Given that the only
compressed sections are debug info, I don't think we are missing much.

It is a small improvement: 0.5% on the geometric mean.

llvm-svn: 331058
2018-04-27 16:29:57 +00:00
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
George Rimar de83cbf37e [ELF] - Never use std::sort.
It turns out we should not use the std::sort anymore.
r327219 added a new wrapper llvm::sort (D39245).
When EXPENSIVE_CHECKS is defined, it shuffles the
input container and that helps to find non-deterministic
ordering.

Patch changes code to use llvm::sort and std::stable_sort
instead of std::sort

Differential revision: https://reviews.llvm.org/D45969

llvm-svn: 330702
2018-04-24 09:55:39 +00:00
Rafael Espindola ea2c78369c Reduce code duplication.
getVA was already implemented in the base class.

llvm-svn: 330036
2018-04-13 16:07:27 +00:00
Simon Atanasyan 1ba194212a [ELF][MIPS] Support linking of PIE for MIPS
MIPS ABI requires creation of the MIPS_RLD_MAP dynamic tag for non-PIE
executables only and MIPS_RLD_MAP_REL tag for both PIE and non-PIE
executables. The patch skips definition of the MIPS_RLD_MAP for PIE
files and defines MIPS_RLD_MAP_REL.

The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map section
relative to the address of the tag itself.

Differential Revision: https://reviews.llvm.org/D43347

llvm-svn: 329996
2018-04-13 08:15:01 +00:00
George Rimar c552619fc1 [ELF] - Reorder local symbols.
This fixes PR36716 (https://bugs.llvm.org/show_bug.cgi?id=36716),

Patch sorts local symbols to match the
following order: file1, local1, hidden1, file2, local2, hidden2 ...

Differential revision: https://reviews.llvm.org/D45325

llvm-svn: 329787
2018-04-11 09:24:27 +00:00
Rafael Espindola 9b6a65b144 Don't ignore addend when a SHF_MERGE section is dead.
This is similar to r329219, but for the entire section. Like r329219 I
don't expect this to have any real impact, it is just more consistent
and simpler.

llvm-svn: 329367
2018-04-06 01:10:33 +00:00
Rafael Espindola 7bd45502fe Initialize OffsetMap earlier.
Now that getSectionPiece uses OffsetMap, it is advantageous to
initialize it earlier.

llvm-svn: 329242
2018-04-05 00:01:57 +00:00
George Rimar 55d717805b [ELF] - Use early return. NFC.
llvm-svn: 329180
2018-04-04 12:36:21 +00:00
Rafael Espindola 6cd7af51e1 Inline initOffsetMap.
In the lld perf builder r328686 had a negative impact in
stalled-cycles-frontend. Somehow that stat is not showing on my
machine, but the attached patch shows an improvement on cache-misses,
which is probably a reasonable proxy.

My working theory is that given a large input the pieces vector is out
of cache by the time initOffsetMap runs.

Both finalizeContents implementation have a convenient location for
initializing the OffsetMap, so this seems the best solution.

llvm-svn: 329117
2018-04-03 21:38:18 +00:00
Peter Collingbourne c5391ce51e ELF: Allow thunks to change size. NFCI.
Differential Revision: https://reviews.llvm.org/D44962

llvm-svn: 328841
2018-03-29 22:32:13 +00:00
Peter Collingbourne cebab4a639 ELF: Make required Thunk methods pure virtual and remove an unused argument. NFC.
Also make certain Thunk methods non-const as this will be required for
an upcoming change.

Differential Revision: https://reviews.llvm.org/D44961

llvm-svn: 328732
2018-03-28 21:33:31 +00:00
Rafael Espindola 816127ea17 Initialize OffsetMap in a known location.
This is a small optimization and avoids the need to use call_once.

llvm-svn: 328686
2018-03-28 03:20:18 +00:00
Zaara Syeda c65ae14766 [ELF] GotSection increment NumEntries when Target saves GlobalOffsetTable in the .got
When the target saves ElfSym::GlobalOffsetTable in the .got rather than
.got.plt, Target->GotHeaderEntriesNum states the number of extra entries
required in the .got. Rather than having to add Target->GotHeaderEntriesNum to
NumEntries in every function which refers to NumEntries, this patch changes the
initial value of NumEntries in the constructor.

Differential Revision: https://reviews.llvm.org/D44744

llvm-svn: 328559
2018-03-26 17:50:52 +00:00
Rafael Espindola 4f058a2c6b Add a SectionBase::getVA helper. NFC.
There were a few too many places duplicating this.

llvm-svn: 328402
2018-03-24 00:35:11 +00:00
Rui Ueyama d37c33aff2 Do not add a dummy entry to SharedFile::Verdefs. NFC.
Previously, we used 0 as an alias for VER_NDX_GLOBAL and had a dummy
entry in SharedFile::Verdefs so that the access to the array is within
its boundary. But that's not straightforwad. We can just stop doing both.

llvm-svn: 328401
2018-03-24 00:25:24 +00:00
Eric Christopher 7baac21bce Fix consitent -> consistent.
llvm-svn: 328010
2018-03-20 18:10:30 +00:00
Rui Ueyama ba32e739b2 Remove GnuHashTableSection::getShift2().
Choosing a Shift2 value based on wordsize is cargo-culted from gold.
Assuming that djb hash is a good hash function, choosing bits [4,9]
shouldn't be any worse or better than choosing bits [5,10]. We shouldn't
have copied that behavior that we can't justify in the first place.

Differential Revision: https://reviews.llvm.org/D44547

llvm-svn: 327921
2018-03-19 23:04:13 +00:00
Zaara Syeda 52ed6eb8d9 [ELF] Add basic support for PPC LE
This patch adds changes to start supporting the Power 64-Bit ELF V2 ABI.
This includes:
- Changing the ElfSym::GlobalOffsetTable to be named .TOC.
- Creating a GotHeader so the first entry in the .got is .TOC.
- Setting the e_flags to be 1 for ELF V1 and 2 for ELF V2

Differential Revision: https://reviews.llvm.org/D44483

llvm-svn: 327871
2018-03-19 17:40:14 +00:00
Peter Smith 3d044f57d4 [ELF] Recommit 327248 with Arm using the .got for _GLOBAL_OFFSET_TABLE_
This is the same as 327248 except Arm defining _GLOBAL_OFFSET_TABLE_ to
be the base of the .got section as some existing code is relying upon it.

For most Targets the _GLOBAL_OFFSET_TABLE_ symbol is expected to be at
the start of the .got.plt section so that _GLOBAL_OFFSET_TABLE_[0] =
reserved value that is by convention the address of the dynamic section.
Previously we had defined _GLOBAL_OFFSET_TABLE_ as either the start or end
of the .got section with the intention that the .got.plt section would
follow the .got. However this does not always hold with the current
default section ordering so _GLOBAL_OFFSET_TABLE_[0] may not be consistent
with the reserved first entry of the .got.plt.

X86, X86_64 and AArch64 will use the .got.plt. Arm, Mips and Power use .got

Fixes PR36555

Differential Revision: https://reviews.llvm.org/D44259

llvm-svn: 327823
2018-03-19 06:52:51 +00:00
Peter Collingbourne 5c902845e5 Revert r327248, "For most Targets the _GLOBAL_OFFSET_TABLE_ symbol is expected to be at"
This change broke ARM code that expects to be able to add
_GLOBAL_OFFSET_TABLE_ to the result of an R_ARM_REL32.

I will provide a reproducer on llvm-commits.

llvm-svn: 327688
2018-03-16 01:01:44 +00:00
Rui Ueyama 4e6b822cdc Separate sentences to clarify a comment.
llvm-svn: 327555
2018-03-14 19:01:00 +00:00
George Rimar 2ab9362bf5 [ELF] - Never create .gnu_hash with NBuckets == 0.
Currently, we can end up with NBuckets==0 and android loader
does not like it (PR36537).

Seems we can go with a minimal amount of changes here for simplicity
and be consistent with gold and so just always use >= 1 value for NBuckets.

Differential revision: https://reviews.llvm.org/D44422

llvm-svn: 327481
2018-03-14 08:52:39 +00:00
Peter Smith 18aa0be36e For most Targets the _GLOBAL_OFFSET_TABLE_ symbol is expected to be at
the start of the .got.plt section so that _GLOBAL_OFFSET_TABLE_[0] =
reserved value that is by convention the address of the dynamic section.
Previously we had defined _GLOBAL_OFFSET_TABLE_ as either the start or end
of the .got section with the intention that the .got.plt section would
follow the .got. However this does not always hold with the current
default section ordering so _GLOBAL_OFFSET_TABLE_[0] may not be consistent
with the reserved first entry of the .got.plt.

X86, X86_64, Arm and AArch64 will use the .got.plt. Mips and Power use .got

Fixes PR36555

Differential Revision: https://reviews.llvm.org/D44259

llvm-svn: 327248
2018-03-11 20:58:18 +00:00
Fangrui Song 0c483024e4 [ELF] Convert {read,write}*be to endianness-aware read/write.
Subscribers: emaste, nemanjai, arichardson, kbarton, llvm-commits

Differential Revision: https://reviews.llvm.org/D44227

llvm-svn: 327156
2018-03-09 18:03:22 +00:00
Rui Ueyama 7c18abf99a Set DF_TEXTREL to executables that need text relocations.
Summary:
If an executable needs text relocations, it should be marked as such so
that the loader can prepare for text relocations. We currently create a
dummy segment with DT_TEXTREL for that purpose.

Generic ABI as of 2000 [1] mentioned that "Its [DT_TEXTREL's] use
has been superseded by the DF_TEXTREL flag". However, it's actually not
superseded even after 18 years. OpenBSD and musl recognize only DT_TEXTREL.
So we still need to set both.

[1] http://www.sco.com/developers/gabi/2000-07-17/ch5.dynamic.html

Reviewers: rafael

Subscribers: emaste, llvm-commits, arichardson

Differential Revision: https://reviews.llvm.org/D43920

llvm-svn: 326503
2018-03-01 22:56:52 +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
George Rimar 563e4f2f58 [ELF] - Introduce getInputSections() helper.
We sometimes need to iterate over input sections for a given
output section. It is not very convinent because we have to iterate
over section descriptions.
Patch introduces getInputSections helper, it simplifies things.

Differential revision: https://reviews.llvm.org/D43574

llvm-svn: 325763
2018-02-22 09:55:28 +00:00
Alexander Richardson 048e2508ad Rename DynamicReloc::getAddend() to computeAddend(). NFC
Summary:
Before the name of the function sounded like it was just a getter for the
private class member Addend. However, it actually calculates the final
value for the r_addend field in Elf_Rela that is used when writing the
.rela.dyn section. I also added a comment to the UseSymVA member to
explain how it interacts with computeAddend().

Differential Revision: https://reviews.llvm.org/D43161

llvm-svn: 325485
2018-02-19 11:00:15 +00:00
Rafael Espindola b960325989 Simplify RelocationBaseSection::addReloc.
Now that we have R_ADDEND, UseSymVA was redundant. We only want to
write the symbol virtual address when using an expression other than
R_ADDEND.

llvm-svn: 325360
2018-02-16 16:53:04 +00:00
Alexander Richardson cfb6093379 Ensure that Elf_Rel addends are always written for dynamic relocations
Summary:
This follows up on r321889 where writing of Elf_Rel addends was partially
moved to RelocationBaseSection. This patch ensures that the addends are
always written to the output section when a input section uses RELA but the
output is REL.

Differential Revision: https://reviews.llvm.org/D42843

llvm-svn: 325328
2018-02-16 10:01:17 +00:00
Rafael Espindola d49866edba Use RelType in a few more places. NFC.
llvm-svn: 325017
2018-02-13 16:06:11 +00:00
Rafael Espindola 35cf8bbe36 Add a simpler version of addReloc. NFC.
Extracted from a patch by Alexander Richardson!

llvm-svn: 325016
2018-02-13 16:03:52 +00:00
Rui Ueyama ac114d27ae s/uncompress/decompress/g.
In lld, we use both "uncompress" and "decompress" which is confusing.
Since LLVM uses "decompress", we should use the same term.

llvm-svn: 324944
2018-02-12 21:56:14 +00:00
Rafael Espindola 7a7a81d9d1 Replace ApplyDynamicRelocs with WriteAddends.
The difference is that WriteAddends also takes IsRela into
consideration.

llvm-svn: 324271
2018-02-05 20:55:46 +00:00
Peter Smith 64f65b02d2 [ELF] Implement --[no-]apply-dynamic-relocs option.
When resolving dynamic RELA relocations the addend is taken from the
relocation and not the place being relocated. Accordingly lld does not
write the addend field to the place like it would for a REL relocation.
Unfortunately there is some system software, in particlar dynamic loaders
such as Bionic's linker64 that use the value of the place prior to
relocation to find the offset that they have been loaded at. Both gold
and bfd control this behavior with the --[no-]apply-dynamic-relocs option.
This change implements the option and defaults it to true for compatibility
with gold and bfd.

Differential Revision: https://reviews.llvm.org/D42797

llvm-svn: 324221
2018-02-05 10:15:08 +00:00
Rafael Espindola 7ce2b4cd13 Simplify by sorting relocations before writing them.
llvm-svn: 323944
2018-02-01 03:17:12 +00:00
Rafael Espindola 6b2b45020c Use 4 as the alignment of .eh_frame_hdr.
It includes 32 bit values and this matches both gold and bfd.

llvm-svn: 323172
2018-01-23 05:23:23 +00:00
Rui Ueyama 2f8af79927 Avoid divisions.
Compiler doesn't know the fact that Config->WordSize * 8 is always a
power of two, so it had to use the div instruction to divide some
number with C.

llvm-svn: 323014
2018-01-20 00:14:16 +00:00
Rui Ueyama 517366c7e0 Make the bloom filter a bit larger.
I created https://reviews.llvm.org/D42202 to see how large the bloom
filter should be. With that patch, I tested various bloom filter sizes
with the following commands:

  $ cmake -GNinja -DCMAKE_BUILD_TYPE=Debug -DLLVM_ENABLE_LLD=true \
    -DLLVM_ENABLE_PROJECTS='clang;lld' -DBUILD_SHARED_LIBS=ON \
    -DCMAKE_SHARED_LINKER_FLAGS=-Wl,-bloom-filter-bits=<some integer> \
    ../llvm-project/llvm
  $ rm -f $(find . -name \*.so.7.0.0svn)
  $ ninja lld
  $ LD_BIND_NOW=1 perf stat bin/ld.lld

Here is the result:

  -bloom-filter-bits=8   0.220351609 seconds
  -bloom-filter-bits=10  0.217146597 seconds
  -bloom-filter-bits=12  0.206870826 seconds
  -bloom-filter-bits=16  0.209456312 seconds
  -bloom-filter-bits=32  0.195092075 seconds

Currently we allocate 8 bits for a symbol, but according to the above
result, that number is not optimal. Even though the numbers follow the
diminishing return rule, the point where a marginal improvement becomes
too small is not -bloom-filter-bits=8 but 12. So this patch sets it to 12.

Differential Revision: https://reviews.llvm.org/D42204

llvm-svn: 323010
2018-01-19 23:54:31 +00:00
Rui Ueyama e2dfdbf0aa Do not pass an argument that can be easily inferred from other argument.
llvm-svn: 322416
2018-01-12 22:29:29 +00:00
George Rimar 9fc2c64b35 [ELF] - Do not use HeaderSize for conditions in PltSection.
Previously we checked (HeaderSize == 0) to find out if
PltSection section is IPLT or PLT. Some targets does not set
HeaderSize though. For example PPC64 has no lazy binding implemented
and does not set PltHeaderSize constant.

Because of that using of both IPLT and PLT relocations worked
incorrectly there (testcase is provided).

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D41613

llvm-svn: 322362
2018-01-12 09:35:57 +00:00
Dimitry Andric 656714a311 Fix thread race between SectionPiece's OutputOff and Live members
Summary:
As reported in bug 35788, rL316280 reintroduces a race between two
members of SectionPiece, which share the same 64 bit memory location.

To fix the race, check the hash before checking the Live member, as
suggested by Rafael.

Reviewers: ruiu, rafael

Reviewed By: ruiu

Subscribers: smeenai, emaste, llvm-commits

Differential Revision: https://reviews.llvm.org/D41884

llvm-svn: 322264
2018-01-11 08:03:22 +00:00
Shoaib Meenai d79bbf4474 [ELF] Fix SysV hash tables with --no-rosegment
When setting up the chain, we copy over the bucket's previous symbol
index, assuming that this index will be 0 (STN_UNDEF) for an unused
bucket (marking the end of the chain). When linking with --no-rosegment,
however, unused buckets will in fact contain the padding value, and so
the hash table will end up containing invalid chains. Zero out the hash
table section explicitly to avoid this, similar to what's already done
for GNU hash sections.

Differential Revision: https://reviews.llvm.org/D41928

llvm-svn: 322259
2018-01-11 06:57:01 +00:00
Rafael Espindola 73584cb587 Centralize Config->IsRela handling.
This merges the two places were we check Config->IsRela to decide how
to write a relocation addend.

llvm-svn: 321889
2018-01-05 20:08:38 +00:00
George Rimar edb61167e5 [ELF] - Add missing dynamic tags when producing output with IRelative relocations only.
This is "Bug 35751 - .dynamic relocation entries omitted if output
contains only IFUNC relocations"

We have InX::RelaPlt and InX::RelaIPlt synthetic sections for PLT relocations.
They are usually live in rela.plt section. Problem appears when InX::RelaPlt
section is empty. In that case we did not produce normal set of dynamic tags
required, because logic was written in the way assuming we always have
non-IRelative relocations in rela.plt.

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D41592

llvm-svn: 321600
2017-12-31 07:42:54 +00:00
George Rimar 3208588e7a [ELF] - Remove excessive checks. NFC.
This was raised in comments for D41592.
With current code we always assign parent
section for Rel[a] sections like
InX::RelaPlt or InX::RelaDyn, so checking
their parent for null is excessive.

llvm-svn: 321581
2017-12-30 08:40:45 +00:00
Rafael Espindola ce3b52c186 Pass an InputFile to the InputSection constructor.
This simplifies toRegularSection and reduces the noise in a followup
patch.

llvm-svn: 321240
2017-12-21 02:11:51 +00:00
Rafael Espindola 5c73c49c9f Detemplate createCommentSection.
It was only templated so it could create a dummy section header that
was immediately parsed back.

llvm-svn: 321235
2017-12-21 01:21:59 +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
Igor Kudrin 5966d15943 [ELF] Fix an assignment command at the end of an .ARM.exidx section.
The value of the symbol in the assignment should include the sentinel entry.

Differential Revision: https://reviews.llvm.org/D41234

llvm-svn: 321154
2017-12-20 08:56:10 +00:00
Rafael Espindola 1037eef8e0 Use references instead of pointers. NFC.
These values are trivially never null. While at it, also use
InputSection instead of InputSectionBase when possible.

llvm-svn: 321126
2017-12-19 23:59:35 +00:00
Rui Ueyama 22e5551ed7 Do not add .dynamic entries that don't have to be added early in the ctor. NFC.
We add dynamic section entries both in the ctor of the class and
DynamicSection::finalizeContents(). Some entries need to be added early
in the ctor because they add strings to .dynstr. Other entries were
intended to be added in finalizeContents(). However, some entries are
added in the ctor even though they don't add strings. This patch
fix the issue.

llvm-svn: 320851
2017-12-15 19:39:59 +00:00
Igor Kudrin a569163b00 Fix a build bot failure.
llvm-svn: 320671
2017-12-14 07:28:11 +00:00
Igor Kudrin f01caab4b7 [ELF] Prevent crash in writing an .ARM.exidx sentinel entry.
We might crash in 'ARMExidxSentinelSection::writeTo()' because it expected
the sentinel entry to be put in the same 'InputSectionDescription' as
the last real entry. This assumption fails if the last output section command
for .ARM.exidx is anything but an input section description, because in this
case 'OutputSection::addSection()' creates a new 'InputSectionDescription'.

Differential Revision: https://reviews.llvm.org/D41105

llvm-svn: 320668
2017-12-14 06:23:50 +00:00
Rafael Espindola 13dbf944d8 Simplify. NFC.
If a section has been replaced (Sec != Sec->Repl) it is not Live.

llvm-svn: 320597
2017-12-13 17:36:53 +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 87e0deaea7 Move RelaPlt and RelaIplt to InX. NFC.
llvm-svn: 320327
2017-12-10 20:07:03 +00:00
Rafael Espindola 58946cdb08 Move RelaDyn to InX. NFC.
llvm-svn: 320324
2017-12-10 19:44:42 +00:00
Rafael Espindola 6d907105c5 Remove this->. NFC.
llvm-svn: 320323
2017-12-10 19:28:32 +00:00
Rafael Espindola d26b52fd34 Remove some includes from InputFiles.h.
They were not used in InputFiles.h and it was getting too easy to add
circular includes.

llvm-svn: 320256
2017-12-09 16:56:18 +00:00
Rui Ueyama 04c821c7e3 Use lambda to simplify code.
Differential Revision: https://reviews.llvm.org/D40994

llvm-svn: 320130
2017-12-08 02:20:50 +00:00
Rafael Espindola d182aaa69d Further simplify .gnu.hash writing. NFC.
llvm-svn: 320072
2017-12-07 18:59:29 +00:00
Rafael Espindola f9f2abe7bd Simplify .gnu.hash writing. NFC.
llvm-svn: 320070
2017-12-07 18:51:19 +00:00
Rafael Espindola 50ca10bb58 Avoid using a temporary std::vector.
With this memory usage when linking clang goes from 174.62MB to
172.77MB.

llvm-svn: 320069
2017-12-07 18:46:03 +00:00
Rui Ueyama c4e50bfc55 Fix broken .gnu.hash section if -no-rosegment is given.
We fill executable sections with trap instructions (0xcc or equivalent).
If a .gnu.hash section was put into an executable segment, we created
corrupted .gnu.hash section. This patch fixes the issue.

llvm-svn: 319863
2017-12-06 00:49:48 +00:00
Rui Ueyama 2278826c60 Cache modulo values for the .gnu.hash section.
This change actually makes the linker slightly faster. My observation
is that, with this patch, link time of clang without debug is about 1%
faster.

Differential Revision: https://reviews.llvm.org/D40697

llvm-svn: 319600
2017-12-02 00:37:13 +00:00
George Rimar 78e27e830d [ELF] - Produce relocation section name consistent with output section name when --emit-reloc used with linker script.
This is for "Bug 35474 - --emit-relocs produces wrongly-named reloc sections".

LLD currently for scripts like:

.text.boot : { *(.text.boot) }
emits relocation section with name .rela.text because does not take
redefined name of output section into account and builds section name
using rules for non-scripted case. Patch fixes this oddness.

Differential revision: https://reviews.llvm.org/D40652

llvm-svn: 319526
2017-12-01 09:04:52 +00:00
Rui Ueyama 1cf7f9cc80 Make .gnu.hash section smaller.
Our on-disk hash table was unnecessarily large. The cost of collision is
not high in the .gnu.hash table because each symbol in the .gnu.hash
table has a hash value with it. So, for each collided symbol, the
dynamic linker just compares an integer, which is pretty cheap.

This patch increases the load factor by about 8. Here's a comparison.

  $ readelf --histogram libclangSema.so.6.0.0svn-new-lld
  Histogram for `.gnu.hash' bucket list length (total of 582 buckets):
   Length  Number     % of total  Coverage
        0  11         (  1.9%)
        1  35         (  6.0%)      1.5%
        2  93         ( 16.0%)      9.5%
        3  108        ( 18.6%)     23.4%
        4  121        ( 20.8%)     44.1%
        5  86         ( 14.8%)     62.6%
        6  63         ( 10.8%)     78.8%
        7  38         (  6.5%)     90.2%
        8  18         (  3.1%)     96.4%
        9  6          (  1.0%)     98.7%
       10  3          (  0.5%)    100.0%

  $ readelf --histogram libclangSema.so.6.0.0svn-old-lld
  Histogram for `.gnu.hash' bucket list length (total of 4093 buckets):
   Length  Number     % of total  Coverage
        0  1498       ( 36.6%)
        1  1545       ( 37.7%)     37.7%
        2  712        ( 17.4%)     72.5%
        3  251        (  6.1%)     90.9%
        4  66         (  1.6%)     97.3%
        5  16         (  0.4%)     99.3%
        6  5          (  0.1%)    100.0%

  $ readelf --histogram libclangSema.so.6.0.0svn-bfd
  Histogram for `.gnu.hash' bucket list length (total of 1004 buckets):
   Length  Number     % of total  Coverage
      0  92         (  9.2%)
        1  227        ( 22.6%)      9.8%
        2  266        ( 26.5%)     32.6%
        3  222        ( 22.1%)     61.2%
        4  115        ( 11.5%)     81.0%
        5  55         (  5.5%)     92.8%
        6  21         (  2.1%)     98.2%
        7  6          (  0.6%)    100.0%

  $ readelf --histogram libclangSema.so.6.0.0svn-gold
  Histogram for `.gnu.hash' bucket list length (total of 2053 buckets):
   Length  Number     % of total  Coverage
        0  671        ( 32.7%)
        1  709        ( 34.5%)     30.4%
        2  470        ( 22.9%)     70.7%
        3  141        (  6.9%)     88.9%
        4  54         (  2.6%)     98.2%
        5  5          (  0.2%)     99.2%
        6  3          (  0.1%)    100.0%

Differential Revision: https://reviews.llvm.org/D40683

llvm-svn: 319503
2017-11-30 23:59:40 +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
Rui Ueyama 2017d52b54 Move Memory.{h,cpp} to Common.
Differential Revision: https://reviews.llvm.org/D40571

llvm-svn: 319221
2017-11-28 20:39:17 +00:00
Rui Ueyama 15475e92c6 Use lambdas to store lazy-evaluated .dynamic entries.
Differential Revision: https://reviews.llvm.org/D40338

llvm-svn: 318938
2017-11-24 02:15:51 +00:00
Rafael Espindola de56343cf0 Simplify as-needed handling.
This is a reduction of a patch by Rui Ueyama.

llvm-svn: 318852
2017-11-22 17:50:42 +00:00
James Henderson f70c5beb22 [ELF] Fix DT_MIPS_LOCAL_GOTNO value for thunks and linker scripts
The MIPS GOT section has a number of local entries based on the number of pages
needed for output sections referenced by GOT page relocations. The number is
recorded in the DT_MIPS_LOCAL_GOTNO dynamic section tag. However, the dynamic tag
is added before assignAddresses has been called, meaning that any section size used
to calculate the value will not include size modifications caused by, for example,
linker scripts and thunks.

This change moves the calculation of DT_MIPS_LOCAL_GOTNO until writeTo, by which
time the output section sizes have been finalized.

Reviewers: ruiu, rafael

Differential Revision: https://reviews.llvm.org/D39493

llvm-svn: 318828
2017-11-22 12:04:21 +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 a5d43d004a Propagate sh_entsize out.
No difference in practice other than having sh_entsize in the output.

This should simplify the patch for handling SHF_MERGE in -r.

Based on a patch by George Rimar.

llvm-svn: 318306
2017-11-15 16:56:20 +00:00
Simon Atanasyan cfa8aa7edb [MIPS] Set STO_MIPS_MICROMIPS flag and less-significant bit for microMIPS symbols
microMIPS symbols including microMIPS PLT records created for regular
symbols needs to be marked by STO_MIPS_MICROMIPS flag in a symbol table.
Additionally microMIPS entries in a dynamic symbol table should have
configured less-significant bit. That allows to escape teaching a
dynamic linker about microMIPS symbols.

llvm-svn: 318097
2017-11-13 22:40:36 +00:00
Simon Atanasyan 5a4e21364c [MIPS] Setup less-significant bit in the .got and .got.plt entries in case of microMIPS code
The less-significant bit signals about microMIPS code for jump/branch
instructions.

llvm-svn: 317741
2017-11-08 23:34:34 +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 48882249dd Rename Body -> Sym.
This patch is mechanically created by

  sed -i -e s/Body/Sym/g lld/ELF/*.{cpp,h}

and clang-format-diff.

llvm-svn: 317392
2017-11-04 00:31:04 +00:00
Rui Ueyama f483da0038 Rename replaceBody -> replaceSymbol.
llvm-svn: 317383
2017-11-03 22:48:47 +00:00
Zachary Turner a104d558d0 Fix variable name.
A mechanical rename caused an illegal name conflict between
a variable and a type, which was picked up by GCC.

llvm-svn: 317380
2017-11-03 22:33:49 +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
Jake Ehrlich 1128dc5e30 Give .note.gnu.build-id section alignment 4
All SHT_NOTE sections should have minimum alignment 4.

Differential Revision: https://reviews.llvm.org/D38907

llvm-svn: 316961
2017-10-30 22:08:11 +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 bda337a8d8 Rename isInCurrentDSO -> isInCurrentOutput.
DSO is short for dynamic shared object, so the function name was a
little confusing because it sounded like it didn't work when we were
a creating statically-linked executable or something.

What we mean by "DSO" here is the current output file that we are
creating. Thus the new name. Alternatively, we could call it the current
ELF module, but "module" is a overloaded word, so I avoided that.

llvm-svn: 316809
2017-10-27 22:54:16 +00:00
Peter Collingbourne 5c54f15c55 ELF: Add support for emitting dynamic relocations in the Android relocation packing format.
The Android relocation packing format is a more compact
format for dynamic relocations in executables and DSOs
that is based on delta encoding and SLEBs. An overview
of the format can be found in the Android source code:
https://android.googlesource.com/platform/bionic/+/refs/heads/master/tools/relocation_packer/src/delta_encoder.h

This patch implements relocation packing using that format.

This implementation uses a more intelligent algorithm for compressing
relative relocations than Android's own relocation packer. As a
result it can generally create smaller relocation sections than
that packer. If I link Chromium for Android targeting ARM32 I get a
.rel.dyn of size 174693 bytes, as compared to 371832 bytes with gold
and the Android packer.

Differential Revision: https://reviews.llvm.org/D39152

llvm-svn: 316775
2017-10-27 17:49:40 +00:00
Peter Smith f0c70f8d34 [ELF] Pre-create ThunkSections at Target specific intervals
When an OutputSection is larger than the branch range for a Target we
need to place thunks such that they are always in range of their caller,
and sufficiently spaced to maximise the number of callers that can use
the thunk. We use the simple heuristic of placing the
ThunkSection at intervals corresponding to a target specific branch range.
If the OutputSection is small we put the thunks at the end of the executable
sections.

Differential Revision: https://reviews.llvm.org/D34689

llvm-svn: 316751
2017-10-27 08:58:28 +00:00
Rui Ueyama f9c66e4b80 Remove a boolean flag `Create`. NFC.
llvm-svn: 316738
2017-10-27 04:15:28 +00:00
Rui Ueyama 79048e4c5c Define a file-local write32 as a wrapper for endian::write32.
llvm-svn: 316736
2017-10-27 03:59:34 +00:00
Rui Ueyama 25f30880f5 Do not use InputSection::getFile<ELFT>() if InputSection::File suffices. NFC.
llvm-svn: 316735
2017-10-27 03:25:04 +00:00
Rui Ueyama 02551abdca De-template EhFrameHdr. NFC.
llvm-svn: 316734
2017-10-27 03:14:24 +00:00
Rui Ueyama 8629752c04 De-template EhReader. NFC.
llvm-svn: 316733
2017-10-27 03:14:09 +00:00
Rui Ueyama 572247f22e De-template EhFrameSection. NFC.
llvm-svn: 316731
2017-10-27 03:13:39 +00:00
Rui Ueyama c055225c6b Make EhFrameHdr pull data from EhFrameSection. NFC.
Previously, EhFrameSection pushes data to EhFrameHdr by calling addFde
function. By making EhFrameHdr pull data from EhFrameSection, we can
eliminate a member from EhFrameHdr.

llvm-svn: 316730
2017-10-27 03:13:24 +00:00
Rui Ueyama 076e2bb10e De-template a few functions. NFC.
llvm-svn: 316729
2017-10-27 03:13:09 +00:00
Rui Ueyama 88f0568ce5 Include an error code when getRandomBytes failed.
In a rare situation, the function can fail (e.g. it fails if it cannot
open /dev/urandom.)

llvm-svn: 316726
2017-10-27 01:25:29 +00:00
Rui Ueyama ed55e6c64f Remove an unnecessary inheritance.
llvm-svn: 316716
2017-10-26 23:54:00 +00:00
Rui Ueyama bfa84325ee Simplify.
Because of the same reason as r316600, I don't think we need a guard
against empty relocations.

llvm-svn: 316710
2017-10-26 22:30:25 +00:00
Rui Ueyama 6e5fda9db8 Move bit operations to a new file, ELF/Bits.h.
llvm-svn: 316707
2017-10-26 21:37:17 +00:00
George Rimar d605f414db [ELF] - Dedupliсate FDEs when sections are ICFed.
When LLD do ICF for 2 identical sections it leaves 2 duplicate entries in .eh_frame
pointing to the same address. After that it fixes .eh_frame_header's header,
so that it says it contains single FDE, though section itself contains 2 
(it contains garbage data at tail).

As a result excessive entries in .eh_frame and excessive dummy data in .eh_frame_header
emited to output. Patch fixes that. This is PR34518.

Differential revision: https://reviews.llvm.org/D38998

llvm-svn: 316648
2017-10-26 09:13:19 +00:00
Bob Haarman b8a59c8aa5 [lld] unified COFF and ELF error handling on new Common/ErrorHandler
Summary:
The COFF linker and the ELF linker have long had similar but separate
Error.h and Error.cpp files to implement error handling. This change
introduces new error handling code in Common/ErrorHandler.h, changes the
COFF and ELF linkers to use it, and removes the old, separate
implementations.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: smeenai, jyknight, emaste, sdardis, nemanjai, nhaehnle, mgorny, javed.absar, kbarton, fedor.sergeev, llvm-commits

Differential Revision: https://reviews.llvm.org/D39259

llvm-svn: 316624
2017-10-25 22:28:38 +00:00
Rui Ueyama 95bf509873 Assume that mergeable input sections are smaller than 4 GiB.
By assuming that mergeable input sections are smaller than 4 GiB,
lld's memory usage when linking clang with debug info drops from
2.788 GiB to 2.019 GiB (measured by valgrind, and that does not include
memory space for mmap'ed files). I think that's a reasonable assumption
given such a large RAM savings, so this patch.

According to valgrind, gold needs 3.54 GiB of RAM to do the same thing.

NB: This patch does not introduce a limitation on the size of
output sections. You can still create sections larger than 4 GiB.

llvm-svn: 316280
2017-10-21 23:20:13 +00:00
George Rimar da8808bf91 [ELF] - Removed outdated comment. NFC.
llvm-svn: 316078
2017-10-18 13:22:21 +00:00
George Rimar 0d6f30e80d [ELF] - Moved, fixed outdated comment. NFC.
It was at wrong place.

llvm-svn: 316077
2017-10-18 13:06:18 +00:00
Rafael Espindola 06ea0ce1c9 Handle shared symbols in the gnu hash construction.
They are special in that they they need to be in the hash table iff we
are linking an executable that preempts them.

llvm-svn: 316065
2017-10-18 06:49:59 +00:00
Rafael Espindola 3038c6beb5 Revert "Bring back the rest of r315721."
This reverts commit r316051.

It fails on a bot.

llvm-svn: 316058
2017-10-18 03:06:45 +00:00
Rafael Espindola 07412df152 Bring back the rest of r315721.
The original patch was reported to break a libcxx bot. Unfortunately I
could not reproduce the issue and the bot log is not available anymore.

This patch changes the handling of shared symbols. I will watch the
bot and see it breaks.

Original message:
--------------------------------------------------------------
Handle shared and lazy symbol in the gnu hash construction.

We were not considering those symbols undefined and they could end up
in the end of the dynamic symbol table.
--------------------------------------------------------------

llvm-svn: 316051
2017-10-18 01:10:05 +00:00
Rafael Espindola 14381cf5a6 Bring back part of r315721.
The original patch was reported to break a libcxx bot. Unfortunately
I could not reproduce the issue and the bot log is not available anymore.

This patch changes the handling of just lazy symbols. I will watch the
bot and see it breaks.

Original message:
--------------------------------------------------------------
Handle shared and lazy symbol in the gnu hash construction.

We were not considering those symbols undefined and they could end up
in the end of the dynamic symbol table.
--------------------------------------------------------------

llvm-svn: 316004
2017-10-17 15:29:11 +00:00
NAKAMURA Takumi 09c234f857 Revert rL315721, "Handle shared and lazy symbol in the gnu hash construction."
It broke check-libcxx with stage1-clang and stage1-lld.

llvm-svn: 315803
2017-10-14 12:21:49 +00:00
Bob Haarman 4f5c8c29ac [lld] Move Threads to Common
Summary:
This will allow using the functionality from other linkers. It is also
a prerequisite for sharing the error logging code.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: emaste, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D38822

llvm-svn: 315725
2017-10-13 18:22:55 +00:00
Rafael Espindola 8bf95e4678 Handle shared and lazy symbol in the gnu hash construction.
We were not considering those symbols undefined and they could end up
in the end of the dynamic symbol table.

llvm-svn: 315721
2017-10-13 18:07:11 +00:00
Rui Ueyama 662bb00028 Hide SymbolBody::IsLocal.
IsLocal member is initialized by the constructor and will never change.
So we don't want to make it directly accessible.

llvm-svn: 315667
2017-10-13 03:37:26 +00:00
Rui Ueyama ca05b6fb79 Remove Symbol::isPreemptible().
Because it was a redundant accessor to Symbol's public member.

llvm-svn: 315609
2017-10-12 19:10:41 +00:00
Rafael Espindola 49419bb303 Use 0 as sh_link when we don't have a dynamic symbol table.
It doesn't make sense to link from an alloc section to a non alloc
one as we were doing.

This matches the behavior of both gold and bfd.

llvm-svn: 315584
2017-10-12 15:05:04 +00:00
Rui Ueyama 2b714b56a9 Split decompressAndMergeSection into two separate functions.
Even though they are called sequentially, they are separate
operations, so it is better to split it.

llvm-svn: 315422
2017-10-11 03:12:53 +00:00
Rui Ueyama 6b394caaf1 Rename Commands -> SectionCommands.
"Commands" was ambiguous because in the linker script, everything is
a command. We used to handle only SECTIONS commands, and at the time,
it might make sense to call them the commands, but it is no longer
the case. We handle not only SECTIONS but also MEMORY, PHDRS, VERSION,
etc., and they are all commands.

llvm-svn: 315409
2017-10-11 01:50:56 +00:00
Rui Ueyama a1b79dff2a Handle input section liveness only in MarkLive.cpp.
The condition whether a section is alive or not by default
is becoming increasingly complex, so the decision of garbage
collection is spreading over InputSection.h and MarkLive.cpp,
which is not a good state.

This moves the code to MarkLive.cpp, to keep the file the central
place to make decisions about garbage collection.

llvm-svn: 315384
2017-10-10 22:59:32 +00:00
James Henderson b5ca92ef73 [ELF] Set Dot initially to --image-base value when using linker scripts
When parsing linker scripts, LLD previously started with a '.' value of 0,
regardless of the internal default image base for the target, and regardless of
switches such as --image-base. It seems reasonable to use a different image base
value when using linker scripts and --image-base is specified, since otherwise the
switch has no effect. This change does this, as well as removing unnecessary
initialisation of Dot where it is not used.

The default image base should not be used when processing linker
scripts, because this will change the behaviour for existing linker script users,
and potentially result in invalid output being produced, as a subsequent assignment
to Dot could move the location counter backwards. Instead, we maintain the existing
behaviour of starting from 0 if --image-base is not specified.

Reviewers: ruiu

Differential Revision: https://reviews.llvm.org/D38360

llvm-svn: 315293
2017-10-10 10:09:35 +00:00
Rui Ueyama c9a4d1c735 Add comments.
llvm-svn: 315268
2017-10-10 03:58:18 +00:00
Rui Ueyama 8befefb2ea Remove OutputSection::updateAlignment.
I feel it is easier to understand without this function.

llvm-svn: 315140
2017-10-07 00:58:34 +00:00
George Rimar 8f3a6c8143 [ELF] - Do not produce broken .dynamic section with --no-rosegment
LLD produces broken .dynamic section when --no-rosegment and at least
one of following options is present:
  1) -z rodynamic is given.
  2) MIPS target.

That happens because code that writes .dynamic assumes target buffer
is zero-filled, what can be not true after LLD fills it with trap
instructions. With one of two options above, .dynamic becomes
SHF_ALLOC section, so can be affected.

Differential revision: https://reviews.llvm.org/D38580

llvm-svn: 315054
2017-10-06 10:06:13 +00:00
George Rimar 2727ce2c1f [ELF] - Do not produce broken .dynsym with --no-rosegment.
We produce broken output currently.
Code that writes .dynsym assumes output buffer is zero-filled,
though that is not always true. When --no-rosegment is given,
buffer can be filled with trap instructions. Patch fixes the issue.

It is relative with PR34705.

Differential revision: https://reviews.llvm.org/D38579

llvm-svn: 315053
2017-10-06 09:56:24 +00:00
Rui Ueyama 0fda1d70bb Fix typo.
llvm-svn: 315042
2017-10-06 04:32:08 +00:00
Rafael Espindola 0038dfa19d Revert "Revert r314810: Use sched_getaffinity instead of std:🧵:hardware_concurrency."
This reverts commit r314924.

The required llvm patch was recommitted.

llvm-svn: 314933
2017-10-04 20:35:05 +00:00
Rui Ueyama 61b9ce217a Revert r314810: Use sched_getaffinity instead of std:🧵:hardware_concurrency.
This reverts commit r314810 because r314809 was reverted.

llvm-svn: 314924
2017-10-04 18:39:51 +00:00
Rui Ueyama 732f4e2778 Remove BssSection::reserveSpace().
We no longer call reserveSpace more than once, so it can be merged with
its constructor.

llvm-svn: 314867
2017-10-04 00:21:17 +00:00
Shoaib Meenai 50d7b36f5e [ELF] Decompress debug info sections early
When reporting a symbol conflict, LLD parses the debug info to report
source location information. Sections have not been decompressed at this
point, so if an object file contains zlib compressed debug info, LLD
ends up passing this compressed debug info to the DWARF parser, which
causes debug info parsing failures and can trigger assertions in the
parser (as the test case demonstrates).

Decompress debug sections when constructing the LLDDwarfObj to avoid
this issue. This doesn't handle GNU-style compressed debug info sections
(.zdebug_*), which at present are simply ignored by LLDDwarfObj; those
can be done in a follow-up.

Differential Revision: https://reviews.llvm.org/D38491

llvm-svn: 314866
2017-10-04 00:19:41 +00:00
Rafael Espindola c804bf9397 Use sched_getaffinity instead of std:🧵:hardware_concurrency.
The issue with std:🧵:hardware_concurrency is that it forwards
to libc and some implementations (like glibc) don't take thread
affinity into consideration.

With this change a llvm program that can execute in only 2 cores will
use 2 threads, even if the machine has 32 cores.

This makes benchmarking a lot easier, but should also help if someone
doesn't want to use all cores for compilation for example.

llvm-svn: 314810
2017-10-03 16:25:48 +00:00
Rui Ueyama f3f9bae842 Add a comment.
llvm-svn: 314746
2017-10-03 00:45:24 +00:00
Rui Ueyama 3f851704c1 Move new lld's code to Common subdirectory.
New lld's files are spread under lib subdirectory, and it isn't easy
to find which files are actually maintained. This patch moves maintained
files to Common subdirectory.

Differential Revision: https://reviews.llvm.org/D37645

llvm-svn: 314719
2017-10-02 21:00:41 +00:00
Simon Atanasyan 649e4d328f [MIPS] Fix PLT entries generation in case of linking regular and microMIPS code
Currently LLD calls the `isMicroMips` routine to determine type of PLT entries
needs to be generated: regular or microMIPS. This routine checks ELF
header flags in the `FirstObj` to retrieve type of linked object files.
So if the first file does not contain microMIPS code, LLD will generate
PLT entries with regular (non-microMIPS) code only.

Ideally, if a PLT entry is referenced by microMIPS code only this entry
should contain microMIPS code, if a PLT entry is referenced by regular
code this entry should contain regular code. In a "mixed" case the PLT
entry can be either microMIPS or regular, but each "cross-mode-call" has
additional cost.

It's rather difficult to implement this ideal solution. But we can
assume that if there is an input object file with microMIPS code, the
most part of the code is microMIPS too. So we need to deduce type of PLT
entries based on finally calculated ELF header flags and do not check
only the first input object file.

This change implements this.
  - The `getMipsEFlags` renamed to the `calcMipsEFlags`. The function
    called from the `LinkerDriver::link`. Result is stored in
    the Configuration::MipsEFlags field.
  - The `isMicroMips` and `isMipsR6` routines access the `MipsEFlags`
    field to get and check calculated ELF flags.
  - New types of PLT records created when necessary.

Differential revision: https://reviews.llvm.org/D37747

llvm-svn: 314675
2017-10-02 14:56:41 +00:00
NAKAMURA Takumi 70947e2224 SyntheticSections.cpp: Appease g++-4.8, s/const/constexpr/
llvm-svn: 314592
2017-09-30 13:40:22 +00:00
Rui Ueyama fbc622d1e4 Fix buildbots.
llvm-svn: 314590
2017-09-30 12:19:08 +00:00
Rui Ueyama c97a70c6f5 Parallelize string merging.
String merging is one of the most time-consuming functions in lld.
This patch parallelize it to speed it up. On my 2-socket 20-core
40-threads Xeon E5-2680 @ 2.8 GHz machine, this patch shorten the
clang debug build link time from 7.11s to 5.16s. It's a 27%
improvement and actually pretty noticeable. In this test condition,
lld is now 4x faster than gold.

Differential Revision: https://reviews.llvm.org/D38266

llvm-svn: 314588
2017-09-30 11:46:26 +00:00
Ben Dunbobbin 73eabf23a4 [ELF] Simpler scheme for handling common symbols
Convert all common symbols to regular symbols after scan.
This means that the downstream code does not to handle common symbols as a special case.

Differential Revision: https://reviews.llvm.org/D38137

llvm-svn: 314495
2017-09-29 09:08:26 +00:00
George Rimar aaf5471429 [ELF] - Detemplate of HashTableSection<ELFT>
Detemplation of one more synthetic section.

Differential revision: https://reviews.llvm.org/D38241

llvm-svn: 314283
2017-09-27 09:14:59 +00:00
George Rimar 5d6efd100b [ELF] - Speedup -r and --emit-relocs
This is "Bug 34688 - lld much slower than bfd when linking the linux kernel"

Inside copyRelocations() we have O(N*M) algorithm, where N - amount of
relocations and M - amount of symbols in symbol table. It isincredibly slow
for linking linux kernel.

Patch creates local search tables to speedup.
With this fix link time goes for me from 12.95s to 0.55s what is almost 23x
faster. (used release LLD).

Differential revision: https://reviews.llvm.org/D38129

llvm-svn: 314282
2017-09-27 09:08:53 +00:00
Rui Ueyama e26b7aafe0 Split MergeSyntheticSection into Merge{Tail,NoTail}Section.
This patch alone is neutral in terms of code readability, but this
change makes a following patch easier to read.

llvm-svn: 314181
2017-09-26 00:54:24 +00:00
George Rimar 19d6ce9d8e [ELF] - Simplify removeUnusedSyntheticSections a bit.
Previously`InX::Got` and InX::MipsGot synthetic sections
were not removed if ElfSym::GlobalOffsetTable was defined.
ElfSym::GlobalOffsetTable is a symbol for _GLOBAL_OFFSET_TABLE_.

Patch moves ElfSym::GlobalOffsetTable check out from removeUnusedSyntheticSections.
Also note that there was no point to check ElfSym::GlobalOffsetTable for MIPS case
because InX::MipsGot::empty() always returns false for non-relocatable case, and in case
of relocatable output we do not create special symbols anyways.

Differential revision: https://reviews.llvm.org/D37623

llvm-svn: 314099
2017-09-25 09:46:33 +00:00
Rui Ueyama f9da2fdc78 Do not sort CU vectors.
We used to sort and uniquify CU vectors, but looks like CU vectors in
.gdb_index sections created by gold are not guaranteed to be sorted.

llvm-svn: 314095
2017-09-25 05:30:39 +00:00
Rui Ueyama 17cc6f6ad9 Speeds up CU vector creation.
We used to use std::set to uniquify CU vector elements, but as we know,
std::set is pretty slow. Fortunately we didn't actually have to use a
std::set here. This patch replaces it with std::vector.

With this patch, lld's -gdb-index overhead when linking a clang debug
build is now about 1 second (8.65 seconds without -gdb-index vs 9.60
seconds with -gdb-index). Since gold takes more than 6 seconds to create
a .gdb_index for the same output, our number isn't that bad.

llvm-svn: 314094
2017-09-25 04:55:27 +00:00
Rui Ueyama 8f222b8158 Fix off-by-one error.
llvm-svn: 314093
2017-09-25 03:40:45 +00:00
Rui Ueyama bbc477c9b6 Do not use StringTableBuilder to build symbol table for .gdb_index.
Previously, we had two levels of hash table lookup. The first hash
lookup uses CachedHashStringRefs as keys and returns offsets in string
table. Then, we did the second hash table lookup to obtain GdbSymbol
pointers. But we can directly map strings to GDbSymbols.

One test file is updated in this patch because we no longer have a '\0'
byte at the start of the string pool, which was automatically inserted
by StringTableBuilder.

This patch speeds up Clang debug build (with -gdb-index) link time by
0.3 seconds.

llvm-svn: 314092
2017-09-25 02:29:51 +00:00
Rui Ueyama 22125d8c84 Compute string hashes early and cache them.
This change alone speeds up linking of Clang debug build with -gdb-index
by 1.2 seconds, from 12.5 seconds to 11.3 seconds. (Without -gdb-index,
lld takes 8.5 seconds to link the same input files.)

llvm-svn: 314090
2017-09-25 01:42:57 +00:00
Rui Ueyama 9f4f490c31 Refactor GdbIndexSection. NFC.
This patch rewrites a part of GdbIndexSection to address the following
issues in the previous implementation:

 - Previously, some struct declarations were in GdbIndex.h while they
   were not used in GdbIndex.cpp. Such structs are moved to
   SyntheticSection.h.

 - The actual implementation were split into GdbIndexSection and GdbHash
   section, but that separation didn't make much sense. They are now
   unified as GdbIndexSection.

In addition to the above changes, this patch splits functions, rename
variables and remove redundant functions/variables to generally improve
code quality.

llvm-svn: 314084
2017-09-24 21:45:35 +00:00
George Rimar 94444b9a07 [ELF] - Fix segfault when processing .eh_frame.
Its a PR34648 which was a segfault that happened because
we stored pointers to elements in DenseMap. 
When DenseMap grows such pointers are invalidated.
Solution implemented is to keep elements by pointer
and not by value.

Differential revision: https://reviews.llvm.org/D38034

llvm-svn: 313741
2017-09-20 09:27:41 +00:00
NAKAMURA Takumi 169dbde262 Revert rL313697, "Compact EhSectionPiece from 32 bytes to 16 bytes."
It broke selfhosting.
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/4896

llvm-svn: 313731
2017-09-20 08:03:18 +00:00
Rui Ueyama 014b0f24ae Compact EhSectionPiece from 32 bytes to 16 bytes.
EhSectionPiece used to have a pointer to a section, but that pointer was
mostly redundant because we almost always know what the section is without
using that pointer. This patch removes the pointer from the struct.

This patch also use uint32_t/int32_t instead of size_t to represent
offsets that are hardly be larger than 4 GiB. At the moment, I think it is
OK even if we cannot handle .eh_frame sections larger than 4 GiB.

Differential Revision: https://reviews.llvm.org/D38012

llvm-svn: 313697
2017-09-19 23:36:48 +00:00
Rui Ueyama 74ea1f0938 Rename CieRecord instance variables.
CieRecord is a struct containing a CIE and FDEs, but oftentimes the
struct itself is named `Cie` which caused some confusion. This patch
renames them `CieRecords` or `Rec`.

llvm-svn: 313681
2017-09-19 21:31:57 +00:00
Rui Ueyama faa38029e2 Simplify. NFC.
llvm-svn: 313667
2017-09-19 20:28:03 +00:00
George Rimar 696a7f9ac6 [ELF] - Introduce std::vector<InputFile *> global arrays.
This patch removes lot of static Instances arrays from different input file 
classes and introduces global arrays for access instead. Similar to arrays we
have for InputSections/OutputSectionCommands.

It allows to iterate over input files in a non-templated code.

Differential revision: https://reviews.llvm.org/D35987

llvm-svn: 313619
2017-09-19 09:20:54 +00:00
Rui Ueyama 34a0dd5283 Rename EhSectionPiece::ID -> EhSectionPiece::Sec.
ID sounds like an identifier, but this is actually a pointer to a section.

llvm-svn: 313588
2017-09-18 23:07:33 +00:00
Rui Ueyama e084aac123 Do not use inheritance for EhSectionPiece.
EhSectionPiece inherited from SectionPiece, but we did not actually use
EhSectionPiece objects as SectionPiece ojbects. They were handled as
distinct types. So it didn't make much sense to use inheritance.

llvm-svn: 313587
2017-09-18 23:07:21 +00:00
Rui Ueyama a6ff617967 Remove useless accessor.
llvm-svn: 313586
2017-09-18 23:07:09 +00:00
Rui Ueyama 27a357c9d9 Remove redundant cast<> and null check.
"Repl" member is guranteed to have a non-null pointer. If an input
section is not merged by ICF, "Repl" points to "this". Otherwise, it
points to some other section. It must not be NULL.

llvm-svn: 313556
2017-09-18 19:15:54 +00:00
Rui Ueyama 56614e41a4 Add a comment about a workaround for ld.gold -r.
llvm-svn: 313095
2017-09-12 23:43:45 +00:00
Rafael Espindola 67df57a242 Remove Offset from Common.
It is not needed since it is always 0.

llvm-svn: 313076
2017-09-12 21:19:09 +00:00
Dmitry Mikulin 1e30f07ce7 Currently lld creates a single section to collect all commons. There is no way
to separate commons based on file name patterns. The following linker script
construct does not work because commons are allocated before section placement
is done and the only synthesized BssSection that holds all commons has no file
associated with it:
SECTIONS { .common_0 : { *file0.o(COMMON) }}

This patch changes the allocation of commons to create a section per common
symbol and let the section logic do the layout.

Differential revision: https://reviews.llvm.org/D37489

llvm-svn: 312796
2017-09-08 16:22:43 +00:00
Andrew Ng 6dee736c91 [LLD] Fix padding of .eh_frame when in executable segment
The default padding for an executable segment is the target trap
instruction which for x86_64 is 0xCC. However, the .eh_frame section
requires the padding to be zero. The code that writes the .eh_frame
section assumes that its segment is zero initialized and does not
explicitly write the zero padding. This does not work when the .eh_frame
section is in the executable segment (for example when using
-no-rosegment).

This patch changes the .eh_frame writing code to explicitly write the
zero padding.

Differential Revision: https://reviews.llvm.org/D37462

llvm-svn: 312706
2017-09-07 08:43:56 +00:00
George Rimar e89c5bfbc2 [ELF] - Never call splitIntoPieces() twice. NFC.
Previously it was called twice for .comment synthetic section.
That created 2 pieces of data, which was deduplicated anyways,
but was not clean.

llvm-svn: 312327
2017-09-01 12:04:52 +00:00
Rui Ueyama 2b6631bb36 Remove GdbIndexSection::finalizeContents.
GdbIndexSection doesn't need lazy finalization because when an instance
of the class is created, we already know all debug info sections.
We can initialize the instnace in the ctor.

llvm-svn: 310931
2017-08-15 17:01:39 +00:00
Rui Ueyama e5d642cf5b Use ArrayRef instead of std::vector&.
llvm-svn: 310930
2017-08-15 17:01:28 +00:00
Rui Ueyama 2114cab93d Update a comment and rename a function.
llvm-svn: 310929
2017-08-15 17:01:17 +00:00
Rui Ueyama 43099e4409 Remove SymbolTable::findInCurrentDSO.
This function doesn't seem to add value to the symbol table as
it is easy to write code without it.

llvm-svn: 310925
2017-08-15 16:03:11 +00:00
Rui Ueyama 9c77d27004 Garbage-collect common symbols.
Liveness is usually a notion of input sections, but this patch adds
"liveness" bit to common symbols because they don't belong to any
input section.

This patch is based on https://reviews.llvm.org/D36520

Differential Revision: https://reviews.llvm.org/D36546

llvm-svn: 310617
2017-08-10 15:54:27 +00:00
Rafael Espindola 6e93d0546a Move File from SymbolBody to Symbol.
With this Symbol has the same size as before, but DefinedRegular goes
from 72 to 64 bytes.

I also find this a bit easier to read. There are fewer places
initializing File for example.

This has a small but measurable speed improvement on all tests (1%
max).

llvm-svn: 310142
2017-08-04 22:31:42 +00:00
James Henderson a5bc09a86f [ELF] Explicitly write null bytes in string tables
Following r309829, if a string table appears in an executable segment, the strings
will not be null terminated. This is a problem, for example, for the .dynstr
section when using -no-rosegment. The strings end up being terminated with 0xcc
because prior to this patch, LLD did not explicitly write the null terminators.
This change fixes that by always writing the null terminators.

Reviewers: rafael

Differential Revision: https://reviews.llvm.org/D36267

llvm-svn: 310042
2017-08-04 09:07:55 +00:00
George Rimar a9b071482d [ELF] - Replace parallelForEach with ranged form.
Makes code a bit more convinent to write/read.

Differential revision: https://reviews.llvm.org/D36089

llvm-svn: 310040
2017-08-04 08:30:16 +00:00
George Rimar 2d23da0033 [ELF] - Use multithreading for building .gdb_index.
Enables multithreaded .gdb_index building.

Differential revision: https://reviews.llvm.org/D36090

llvm-svn: 309688
2017-08-01 14:57:13 +00:00
Rafael Espindola 8c022ca783 Merge OutputSectionCommand and OutputSection.
This is a bit of a hack, but it is *so* convenient.

Now that we create synthetic linker scripts when none is provided, we
always have to handle paired OutputSection and OutputsectionCommand and
keep a mapping from one to the other.

This patch simplifies things by merging them and creating what used to
be OutputSectionCommands really early.

llvm-svn: 309311
2017-07-27 19:22:43 +00:00
Rui Ueyama 709fb2bb10 Rename ObjectFile -> ObjFile.
Rename it because it was too easy to conflict with llvm::object::ObjectFile
which broke buildbots several times.

llvm-svn: 309199
2017-07-26 22:13:32 +00:00
Rafael Espindola 244ef98161 Detemplate SymbolTable.
NFC, just makes it easier to access from non templated code.

llvm-svn: 309152
2017-07-26 18:42:48 +00:00
Rui Ueyama bc2c9e0278 Do not strip SHF_GROUP in elf::decompressAndMergeSections().
SHF_GROUP flag should have been removed when the control reaches here
because InputSectionBase turns the flag off. So this code should be
redundant.

llvm-svn: 308680
2017-07-20 21:42:30 +00:00
Rafael Espindola 8b1afd59c3 Speed up gdb index creation.
With that in place we can use lld's own infrastructure for the low
level detail of dwarf parsing.

With this we don't decompress sections twice, we don't scan all
realocations and even with this simplistic implementation linking
clang with gdb index goes from 34.09 seconds to 20.80 seconds.

llvm-svn: 308544
2017-07-19 22:27:35 +00:00
George Rimar b939d32f53 [ELF] - Fix member name: alignment -> Alignment. NFC.
llvm-svn: 308300
2017-07-18 11:59:19 +00:00
George Rimar 67c60727ce [ELF] - Apply clang-format. NFC.
llvm-svn: 308297
2017-07-18 11:55:35 +00:00
George Rimar f525c928cf [ELF] - Implement filter library support (-F / --filter)
This is PR33766.

-F name
--filter=name
When creating an ELF shared object, set the internal DT_FILTER field to the specified name. This tells the dynamic linker that the symbol table of the shared object which is being created should be used as a filter on the symbol table of the shared object name.

If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the DT_FILTER field. The dynamic linker will resolve symbols according to the symbol table of the filter object as usual, but it will actually link to the definitions found in the shared object name. Thus the filter object can be used to select a subset of the symbols provided by the object name.
(https://linux.die.net/man/1/ld).

Shared Objects as Filters:
https://docs.oracle.com/cd/E19683-01/817-3677/chapter4-31738/index.html

Differential revision: https://reviews.llvm.org/D35352

llvm-svn: 308167
2017-07-17 09:43:18 +00:00
Igor Kudrin 202a9f6817 [ELF] Fix writing the content of the .got section in a wrong place.
In filling the .got sections, InputSection::OutSecOff was added twice
when finding the position to apply a relocation: first time in
InputSection::writeTo() and then in SectionBase::getOffset().

Differential revision: https://reviews.llvm.org/D34232

llvm-svn: 308003
2017-07-14 08:10:45 +00:00
Rafael Espindola 300b38678c Refactor gdb index creation.
I have a patch to let DwarfContext defer to lld for getting section
contents and relocations.

That is a pretty big performance improvement.

This is just a refactoring to make that easier to do.

This change makes the *creation* of gdb index a dedicated step and
makes that templated. That is so that we can uses Elf_Rel in the code.

llvm-svn: 307867
2017-07-12 23:56:53 +00:00
George Rimar 1b51b7fc7f [ELF] - Fail the link if something happens on DWARF parsing stage of -gdb-index building
This is relative to PR33173,

Previously if something wrong happened on DWARF parsers side during parsing
object for building gdb index (like was in PR: unsupported relocation) 
then LLD continued and finished the link. DWARF parsers sure showed error
message on their side, but that is all.

Patch changes behavior to fail the link in this case and show more
detailed message.

Differential revision: https://reviews.llvm.org/D34814

llvm-svn: 307370
2017-07-07 09:18:05 +00:00
Rafael Espindola 4cc0cd6556 Use Entry::SecSize in a couple of cases.
This avoids having to compute relocation section sizes early, removing
the last use of assignOffsets.

llvm-svn: 307219
2017-07-05 23:06:59 +00:00
Rui Ueyama 0cc1483562 Add basic 64-bit SPARC support
Add support for the most common SPARC relocations.
Make DT_PLTGOT point to the PLT on SPARC.
Mark the PLT as executable on SPARC.

This adds a basic test that creates a SPARV9 executable
that invokes the exit system call on OpenBSD.

Patch by Mark Kettenis.

Differential Revision: https://reviews.llvm.org/D34618

llvm-svn: 306565
2017-06-28 17:05:39 +00:00
George Rimar dbe843d602 [ELF] - Do not set st_size field of SHT_UNDEF symbols.
This fixes PR33598.

Size field for undefined symbols is not significant.
Setting it to fixed value, like zero, may be useful though.

For example when we have 2 DSO's, like in this PR, if lower level DSO may
change slightly (in part of some symbol's st_size)  and higher-level DSO is
rebuilt, then tools that monitoring checksum of high level DSO file can notice
it and trigger cascade of some other unnecessary actions. 
If we set st_size to zero, that can be avoided.

Differential revision: https://reviews.llvm.org/D34673

llvm-svn: 306526
2017-06-28 09:51:33 +00:00
Peter Collingbourne dc7936eced ELF: Move section merging before ICF. NFCI.
Differential Revision: https://reviews.llvm.org/D34093

llvm-svn: 305176
2017-06-12 00:00:51 +00:00
George Rimar b4b7b74b5a [ELF] - Fix build bot.
SyntheticSections.cpp:1773:29: error: chosen constructor is explicit in copy-initialization
        CuVectors.push_back({});
                            ^~
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/set:428:14: note: constructor declared here
    explicit set(const value_compare& __comp = value_compare())
             ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/vector:702:59: note: passing argument to parameter '__x' here
    _LIBCPP_INLINE_VISIBILITY void push_back(value_type&& __x);

llvm-svn: 305054
2017-06-09 04:48:56 +00:00
George Rimar 8666562e89 [ELF] - Make implementation of .gdb index to be more natural for futher paralleling.
This patch reimplements .gdb_index in more natural way,
that makes proccess of switching to multithreaded index building to
be trivial. 

Differential revision: https://reviews.llvm.org/D33552

llvm-svn: 304927
2017-06-07 16:59:11 +00:00
Rafael Espindola 66d98495b0 Delete dead function.
llvm-svn: 304914
2017-06-07 14:24:32 +00:00
George Rimar 0641b8b4d3 [ELF] - Simplify readAddressArea() implementation.
Approach significantly simplifies LLD .gdb_index code and makes it much faster.
Also it should resolve issues, like D33176 tries to address once and forever in a clean way.

LLC binary linking without patch and without --gdb-index: 1,599241063
LLC binary linking without patch and with --gdb-index: 6,064316262
LLC binary linking with patch and with --gdb-index: 4,116792104

Time spent for building gdbindex changes from (6,064316262 - 1,599241063 == 4,465075199)
to (4,116792104- 1,599241063 == 2,517551041).
That is 2,517551041/4,465075199 = 0,564 or about 44% speedup.

Differential revision: https://reviews.llvm.org/D33183

llvm-svn: 304895
2017-06-07 10:52:02 +00:00
Zachary Turner 264b5d9e88 Move Object format code to lib/BinaryFormat.
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.

Differential Revision: https://reviews.llvm.org/D33843

llvm-svn: 304864
2017-06-07 03:48:56 +00:00
Rafael Espindola db5e56f7b2 Store a single Parent pointer for InputSectionBase.
Before InputSectionBase had an OutputSection pointer, but that was not
always valid. For example, if it was a merge section one actually had
to look at MergeSec->OutSec.

This was brittle and caused bugs like the one fixed by r304260.

We now have a single Parent pointer that points to an OutputSection
for InputSection, but to a SyntheticSection for merge sections and
.eh_frame. This makes it impossible to accidentally access an invalid
OutSec.

llvm-svn: 304338
2017-05-31 20:17:44 +00:00
Rafael Espindola 0dc2510762 Simplify. NFC.
llvm-svn: 304330
2017-05-31 19:26:37 +00:00
Rafael Espindola 23db636080 Simplify. NFC.
llvm-svn: 304328
2017-05-31 19:22:01 +00:00
Rafael Espindola b47c6e5cbd Fix a crash.
We would crash if a SHF_LINK_ORDER section pointed to a non
InputSection section. Since those sections are not merged in order,
SHF_LINK_ORDER is pretty meaningless and we can error on that case.

llvm-svn: 304327
2017-05-31 19:09:52 +00:00
Peter Smith ea79b215d6 [ELF] .ARM.exidx sentinel section should use InputSectionDescriptions.
This change converts the writing of the .ARM.exidx sentinel section to use
the InputSectionDescriptions instead of OutputSection::Sections this is in
preparation for the retirement of OutputSection::Sections.
    
Differential Revision: https://reviews.llvm.org/D33500

llvm-svn: 304289
2017-05-31 09:02:21 +00:00
Rafael Espindola 180de970c8 Fix crash when processing relocations in .eh_frame.
This happens when attempting to link shared libraries using exceptions on
MIPS. It requires -z notext because clang generates R_MIPS_64 relocations
inside .eh_frame.
The crash happened because for EhInputSection the OutSec member is null.

Patch by Alexander Richardson!

llvm-svn: 304260
2017-05-31 00:23:23 +00:00
Petr Hosek ffa786f465 [lld][ELF]Add option to make .dynamic read only
The .dynamic section of an ELF almost doesn't need to be written to with
the exception of the DT_DEBUG entry. For several reasons having a read
only .dynamic section would be useful. This change adds the -z keyword
"rodynamic" which forces .dynamic to be read-only. In this case DT_DEBUG
will not be emited.

Patch by Jake Ehrlich

Differential Revision: https://reviews.llvm.org/D33251

llvm-svn: 304024
2017-05-26 19:12:38 +00:00
George Rimar 1ef2e237bf [ELF] - Attemp to fix bot
http://lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/8549/steps/build_Lld/logs/stdio

llvm-svn: 304016
2017-05-26 18:07:25 +00:00
George Rimar 8684dbaa14 [ELF] - Follow up for r303975. NFCi.
Restore bitwise-or order and fix warning
(was changed by mistake during resolve of conflicts).

llvm-svn: 303976
2017-05-26 12:16:39 +00:00
George Rimar c1a0364cd6 [ELF] - Do not produce duplicate values in .gdb_index's constant pool area.
I found this when builded llc binary using gcc 5.4.1 + LLD.
gcc produces duplicate entries in .debug_gnu_pubtypes section, ex:

UnifyFunctionExitNodes.cpp.o has:
0x0000ac07 EXTERNAL TYPE "std::success_type<void*>"
0x0000ac07 EXTERNAL TYPE "std::success_type<void*>"

clang produces single entry here:
0x0000d291 EXTERNAL TYPE "std::__success_type<void *>"

If we link output from gcc with LLD, that would produce excessive duplicate
entries in .gdb_index constant pool area. That does not seem affect gdb work,
but makes .gdb_index larger than it can be.

I also checked that gold filters out such duplicates too. Patch fixes it.

Differential revision: https://reviews.llvm.org/D32647

llvm-svn: 303975
2017-05-26 12:09:26 +00:00
George Rimar 5f5905eea8 [ELF] - Simplify implementation of constant pool when building .gdb_index
https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html says:
"A CU vector in the constant pool is a sequence of offset_type values. 
The first value is the number of CU indices in the vector. 
Each subsequent value is the index and symbol attributes of a CU in the CU list."

Previously we keeped 2 values until the end, what was useless. 
Initially was a part of D32647, though it is possible to split out. 
Patch do that.

Differential revision: https://reviews.llvm.org/D33551

llvm-svn: 303973
2017-05-26 12:01:40 +00:00
Rafael Espindola f307d3ea4d Remove dummy cast. NFC.
llvm-svn: 303948
2017-05-26 00:37:39 +00:00
Rafael Espindola a28414d7ec Simplify MipsRldMapSection::writeTo.
It is not clear why a synthetic section wants to use padding defined
in the linker script. The padding is for the space between sections.

It was also missing a test.

llvm-svn: 303812
2017-05-24 22:04:32 +00:00
Rafael Espindola 55b169bf5d Move writeTo to OutputSectionCommand.
This reduces how many times we have to map from OutputSection to
OutputSectionCommand. It is a required step to moving
clearOutputSections earlier.

In order to always use writeTo in OutputSectionCommand we have to call
fabricateDefaultCommands for -r links and move section compression
after it.

llvm-svn: 303784
2017-05-24 18:08:04 +00:00
Rafael Espindola a6465bbb72 Alternative way to detemplate GotSection.
GetSection is a template because write calls relocate.

relocate has two parts. The non alloc code really has to be a
template, as it is looking a raw input file data.

The alloc part is only a template because of getSize.

This patch folds the value of getSize early, detemplates
getRelocTargetVA and splits relocate into a templated non alloc case
and a regular function for the alloc case. This has the nice advantage
of making sure we collect all the information we need for relocations
before getting to InputSection::relocateNonAlloc.

Since we know got is alloc, it can just call the function directly and
avoid the template.

llvm-svn: 303355
2017-05-18 16:45:36 +00:00
George Rimar d8daafd0fb [ELF] - Update for LLVM's r303163 change. NFCi.
llvm-svn: 303164
2017-05-16 12:34:51 +00:00
George Rimar 390242d0e9 [ELF] - Detemplate elf::addSyntheticLocal(). NFC.
llvm-svn: 303155
2017-05-16 10:11:36 +00:00
George Rimar 69b17c35d9 [ELF] - Detemplate access to SymTab, DynSymTab, GnuHashTab. NFC.
Follow up for r303150.

llvm-svn: 303153
2017-05-16 10:04:42 +00:00
George Rimar f45f681609 [ELF] - Detemplate GnuHashTableSection and SymbolTableSection sections.
SymbolTableBaseSection was introduced.

Detemplation of SymbolTableSection should allow to detemplate more things.

Differential revision: https://reviews.llvm.org/D33124

llvm-svn: 303150
2017-05-16 08:53:30 +00:00
Peter Collingbourne 0a2678e9aa ELF: --gdb-index: Change findSection to return an InputSection.
We should only ever expect this function to return a regular
InputSection; I would not expect a function definition to be in a
MergeInputSection or EhInputSection. We were previously crashing
in writeTo if this function returned a section that was not an
InputSection because we do not set OutSec for such sections.

This can happen in practice if a function is defined in an empty
section which shares its offset-in-file with a MergeInputSection,
as in the provided test case.

A better fix for this bug would be to fix the
DWARFUnit::collectAddressRanges() interface to provide section
information (see D33183), but this at least fixes the crash.

Differential Revision: https://reviews.llvm.org/D33176

llvm-svn: 303089
2017-05-15 17:59:21 +00:00
Peter Collingbourne c5bee3212b ELF: --gdb-index: Do not add dead sections to the address area.
Fixes PR33032.

Differential Revision: https://reviews.llvm.org/D33175

llvm-svn: 303088
2017-05-15 17:53:26 +00:00
George Rimar b4081bb0ab [ELF] - Stop support of DF_STATIC_TLS flag.
This reverts changes introduced in r302414 "[ELF] - Set DF_STATIC_TLS flag for i386 target."

Because DF_STATIC_TLS does not look to be used by glibc or anything else.

llvm-svn: 302884
2017-05-12 08:04:58 +00:00
Rafael Espindola 88ab9fb163 Detemplate the got.
This is a bit hackish, but allows for a lot of followup cleanups.

llvm-svn: 302845
2017-05-11 23:26:03 +00:00
Rafael Espindola 5ab1989584 Reduce templating. NFC.
llvm-svn: 302843
2017-05-11 23:16:43 +00:00
Rafael Espindola 895aea6d15 Reduce template usage. NFC.
llvm-svn: 302832
2017-05-11 22:02:41 +00:00
Rafael Espindola b3aa2c9b9e Reduce template usage. NFC.
llvm-svn: 302828
2017-05-11 21:33:30 +00:00
Rafael Espindola 4b1c3696e3 Reduce template usage. NFC.
llvm-svn: 302826
2017-05-11 21:23:38 +00:00
Rui Ueyama 33d903d1b0 Rename parallelFor -> parallelForEachN.
So that it is clear that the function is a wrapper for for_each_n.

llvm-svn: 302718
2017-05-10 20:02:19 +00:00
Rafael Espindola c5b612b8b4 Don't use section names in getFiller. NFC.
This is just faster and avoids using names.

llvm-svn: 302661
2017-05-10 14:01:13 +00:00
George Rimar 1564122b05 [ELF] - Set DF_STATIC_TLS flag for i386 target.
This is PR32437.

DF_STATIC_TLS
If set in a shared object or executable, this flag instructs the 
dynamic linker to reject attempts to load this file dynamically. 
It indicates that the shared object or executable contains code 
using a static thread-local storage scheme. Implementations need 
not support any form of thread-local storage.

Patch checks if IE/LE relocations were used to check if code uses
static model. If so it sets the DF_STATIC_TLS flag.

Differential revision: https://reviews.llvm.org/D32354

llvm-svn: 302414
2017-05-08 10:24:38 +00:00
Rafael Espindola a8a1a4fc30 Avoid empty .eh_frame sections.
Strip on OpenBSD does not correctly handle an empty .eh_frame section
and produces broken binaries in that case. Currently lld creates such
an empty .eh_frame section, despite the fact that the OpenBSD crtend.o
explicitly inserts a terminator. The Linux LSB "standard":

https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME

explicitly says that

    The .eh_frame section shall contain 1 or more Call Frame Information (CFI) records.

This diff includes a test that specifically tests the issue I'm seeing
on OpenBSD.

Patch by Mark Kettenis!

llvm-svn: 301931
2017-05-02 15:45:31 +00:00
Rui Ueyama bd27849e4b Rename RPath Rpath for consistency. NFC.
For an option -foo-bar-baz, we have Config->FooBarBaz. Since -rpath is
-rpath and not -r-path, it should be Config->Rpath instead Config->RPath.

llvm-svn: 301759
2017-04-29 23:06:43 +00:00
Rui Ueyama 42fca6e794 Recommend users use readelf instead of objdump to dump .comment contents.
readelf's output is much easier to read than objdump's as you can see below.

  $ readelf --string-dump .comment foo
  String dump of section '.comment':
    [     1]  GCC: (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4
    [    2c]  clang version 5.0.0
    [    41]  Linker: LLD 5.0.0

  $ objdump -j .comment -s foo
  Contents of section .comment:
   0000 00474343 3a202855 62756e74 7520342e  .GCC: (Ubuntu 4.
   0010 382e342d 32756275 6e747531 7e31342e  8.4-2ubuntu1~14.
   0020 30342e33 2920342e 382e3400 636c616e  04.3) 4.8.4.clan
   0030 67207665 7273696f 6e20352e 302e3020  g version 5.0.0
   0040 004c696e 6b65723a 204c4c44 20352e30  .Linker: LLD 5.0
   0050 2e3000                               .0.

llvm-svn: 301515
2017-04-27 04:50:08 +00:00