Commit Graph

113 Commits

Author SHA1 Message Date
Rafael Espindola c7e1e03498 Store an ArrayRef for Data in InputSectionData.
llvm-svn: 281210
2016-09-12 13:13:53 +00:00
Rafael Espindola 54f1614ec1 Revert "Revert "Compact InputSectionData from 64 to 48 bytes. NFC.""
This reverts commit r281096.

The previous link errors should be fixed by r281208.

llvm-svn: 281209
2016-09-12 13:06:10 +00:00
Rafael Espindola 78fe670994 Revert "Compact InputSectionData from 64 to 48 bytes. NFC."
This reverts commit r281084.

The link was failing on some bots. No idea why. I will try to
reproduce it on Monday.

llvm-svn: 281096
2016-09-09 21:20:30 +00:00
Rafael Espindola 82621dcb10 Compact InputSectionData from 64 to 48 bytes. NFC.
llvm-svn: 281084
2016-09-09 19:42:11 +00:00
Rafael Espindola 042a3f209b Compute section names only once.
This simplifies error handling as there is now only one place in the
code that needs to consider the possibility that the name is
corrupted. Before we would do it in every access.

llvm-svn: 280937
2016-09-08 14:06:08 +00:00
Rafael Espindola 16853bb00f Pack InputSectionData from 72 to 64 bytes. NFC.
llvm-svn: 280925
2016-09-08 12:33:41 +00:00
Rafael Espindola 0a75850fa7 Move field to the base class. NFC.
llvm-svn: 280858
2016-09-07 20:41:19 +00:00
Rafael Espindola 664c6522fa Delete dead field. NFC.
llvm-svn: 280856
2016-09-07 20:37:34 +00:00
Eugene Leviant 97403d15ee Eliminate LayoutInputSection class
Previously we used LayoutInputSection class to correctly assign
symbols defined in linker script. This patch removes it and uses
pointer to preceding input section in SymbolAssignment class instead.

Differential revision: https://reviews.llvm.org/D23661

llvm-svn: 280348
2016-09-01 09:55:57 +00:00
Rafael Espindola e7553e4eac Delete unnecessary template.
llvm-svn: 280237
2016-08-31 13:28:33 +00:00
Simon Atanasyan 85c6b44817 [ELF][MIPS] Support .MIPS.abiflags section
This section supersedes .reginfo and .MIPS.options sections. But for now
we have to support all three sections for ABI transition period.

llvm-svn: 278482
2016-08-12 06:28:49 +00:00
Eugene Leviant ceabe80e97 [ELF] Symbol assignment within output section description
llvm-svn: 278322
2016-08-11 07:56:43 +00:00
Rui Ueyama d6bd1371fc Include filenames and section names to error messages.
llvm-svn: 277566
2016-08-03 04:39:42 +00:00
Rui Ueyama 09d4f177fc Remove dependency to SymbolTable from CommonInputSection.
llvm-svn: 277103
2016-07-29 03:39:44 +00:00
Rui Ueyama ad10c3d8d4 Make CommonInputSection singleton class.
All other singleton instances are accessible globally.
CommonInputSection shouldn't be an exception.

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

llvm-svn: 277034
2016-07-28 21:05:04 +00:00
Eugene Leviant 3e6b027705 [ELF] Allows setting section for common symbols in linker script
llvm-svn: 277023
2016-07-28 19:24:13 +00:00
Rafael Espindola 2deeb6093d Fix PR28575.
Not all relocations from a .eh_frame that point to an executable
section should be ignored. In particular, the relocation finding the
personality function should not.

This is a reduction from trying to bootstrap a static lld on linux.

llvm-svn: 276329
2016-07-21 20:18:30 +00:00
Rafael Espindola 6eae9f2c67 Delete SplitInputSection.
This opens the way for having a different Piece type for EhInputSection.

llvm-svn: 276275
2016-07-21 13:32:37 +00:00
Rafael Espindola 2197311c31 Delete EhInputSection::getOffset.
We no longer need it for relocations in .eh_frame.

The only relocations that point to .eh_frame are the ones trying to
find the output .eh_frame.

This actually fixes a bug in the symbol value code. It was not
handling -1 as an indicator for a piece not being included in the
output.

llvm-svn: 276175
2016-07-20 20:19:58 +00:00
Eugene Leviant e63d81bd05 [ELF] Create output sections in LinkerScript class
llvm-svn: 276121
2016-07-20 14:43:20 +00:00
George Rimar 5d53d1f42c [ELF] - Make few members of Writer to be global and export them for reuse
Creating sections on linkerscript side requires some methods
that can be reused if are exported from writer.

Patch implements that change.

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

llvm-svn: 275162
2016-07-12 08:50:42 +00:00
Peter Smith fb05cd997c Recommit R274836 Add Thunk support framework for ARM and Mips
The TinyPtrVector of const Thunk<ELFT>* in InputSections.h can cause 
build failures on certain compiler/library combinations when Thunk<ELFT> 
is not a complete type or is an abstract class. Fixed by making Thunk<ELFT>
non Abstract.

type or is an abstract class 

llvm-svn: 274863
2016-07-08 16:10:27 +00:00
Peter Smith eeb827447e Revert R274836 Add Thunk support framework for ARM and Mips
This seems to be causing a buildbot failure on lld-x86_64-freebsd. Will
reproduce locally and fix. 

llvm-svn: 274841
2016-07-08 12:25:50 +00:00
Peter Smith de01b98a26 Add Thunk support framework for ARM and Mips
Generalise the Mips LA25 Thunk code and implement ARM and Thumb
    interworking Thunks.
    
    - Introduce a new module Thunks.cpp to store the Target Specific Thunk
      implementations.
    - DefinedRegular and Shared have a ThunkData field to record Thunk.
    - A Target can have more than one type of Thunk.
    - Support PC-relative calls to Thunks.
    - Support Thunks to PLT entries.
    - Existing Mips LA25 Thunk code integrated.
    - Support for ARMv7A interworking Thunks.
    
    Limitations:
    - Only one Thunk per SymbolBody, this is sufficient for all currently
      implemented Thunks.
    - ARM thunks assume presence of V6T2 MOVT and MOVW instructions.

    Differential revision: http://reviews.llvm.org/D21891

llvm-svn: 274836
2016-07-08 11:13:40 +00:00
Rui Ueyama 1d12ac1d11 Fix endianness issue.
Previously, ch_size was read in host byte order, so if a host and
a target are different in byte order, we would produce a corrupted
output.

llvm-svn: 274729
2016-07-07 03:55:55 +00:00
George Rimar 602fbee9fc [ELF] - Support of compressed input sections implemented.
Patch implements support of zlib style compressed sections.
SHF_COMPRESSED flag is used to recognize that decompression is required.
After that decompression is performed and flag is removed from output.

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

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

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

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

llvm-svn: 273532
2016-06-23 04:33:42 +00:00
Rui Ueyama 424b408165 Rename Align -> Alignment.
I think it is me who named these variables, but I always find that
they are slightly confusing because align is a verb.
Adding four letters is worth it.

llvm-svn: 272984
2016-06-17 01:18:46 +00:00
Davide Italiano e6c8fa4530 [ELF] Unbreak build with GCC.
Differential Revision:  http://reviews.llvm.org/D20777

llvm-svn: 271148
2016-05-28 23:27:38 +00:00
Rui Ueyama 406b469de4 Avoid doing binary search.
MergedInputSection::getOffset is the busiest function in LLD if string
merging is enabled and input files have lots of mergeable sections.
It is usually the case when creating executable with debug info,
so it is pretty common.

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

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

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

Before:

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

       6.579106511 seconds time elapsed                                          ( +-  0.09% )

After:

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

       6.307411828 seconds time elapsed                                          ( +-  0.19% )

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

llvm-svn: 270999
2016-05-27 14:39:13 +00:00
Rui Ueyama d884927463 Make SectionPiece 8 bytes smaller on LP64.
This patch makes SectionPiece class 8 bytes smaller on platforms
on which pointer size is 8 bytes. Sean suggested in a post commit
review for r270340 that this could make a differentce, and it
actually is. Time to link clang (with debug info) improved from
6.725 seconds to 6.589 seconds or by about 2%.

Differential Revision: http://reviews.llvm.org/D20613

llvm-svn: 270717
2016-05-25 16:37:01 +00:00
Rui Ueyama 0fcdc730ad Create Relocations.cpp and move scanRelocs there.
scanReloc and the functions on which scanReloc depends is in total
more than 600 lines of code. Since scanReloc does not depend on Writer,
it is better to move it into a separate file.

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

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

Sorry, I commited the wrong branch :-(

llvm-svn: 270554
2016-05-24 12:12:06 +00:00
Rafael Espindola dba64b8ea4 Simplify. Thanks to Rui for the suggestion.
llvm-svn: 270551
2016-05-24 11:53:15 +00:00
Rui Ueyama 0b9a90364b Rename EHInputSection -> EhInputSection.
llvm-svn: 270532
2016-05-24 04:19:20 +00:00
Rui Ueyama b91bf1a9a0 Do not split mergeable sections if they are gc'ed.
Previously, mergeable section's constructors did more than just
setting member variables; it split section contents into small
pieces. It is not always computationally cheap task because if
the section is a mergeable string section, it needs to scan the
entire section to split them by NUL characters.

If a section would be thrown away by GC, that cost ended up
being a waste of time. It is going to be larger problem if the
section is compressed -- the whole time to uncompress it and
split it up is going to be a waste.

Luckily, we can defer section splitting after GC. We just have
to remember which offsets are in use during GC and apply that later.
This patch implements it.

Differential Revision: http://reviews.llvm.org/D20516

llvm-svn: 270455
2016-05-23 16:55:43 +00:00
Rui Ueyama 88abd9b300 Move splitInputSection from EHOutputSection to EHInputSection.
llvm-svn: 270385
2016-05-22 23:53:00 +00:00
Rui Ueyama 34dc99e2c5 Store section contents to SectionPiece. NFC.
So that we don't need to cut a slice when we use a SectionPiece.

llvm-svn: 270348
2016-05-22 01:15:32 +00:00
Rui Ueyama 90fa3722d2 Simplify SplitInputSection::getRangeAndSize.
This patch adds Size member to SectionPiece so that getRangeAndSize
can just return a SectionPiece instead of a std::pair<SectionPiece *, uint_t>.
Also renamed the function.

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

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

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

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

llvm-svn: 270277
2016-05-20 21:23:52 +00:00
Simon Atanasyan 4e3a15c9f3 [ELF][MIPS] Rename R_MIPS_GOT_xxx relocation expression kinds
New names reflect purpose of corresponding GOT entries better.
Both expression types related to entries allocated in the 'local'
part of MIPS GOT. R_MIPS_GOT_LOCAL_PAGE is for entries contain 'page'
addresses. R_MIPS_GOT_LOCAL is for entries contain 'full' address.

llvm-svn: 269597
2016-05-15 18:13:50 +00:00
Rafael Espindola 3e0b7837bf Cache result when tail merging too.
This speeds up a link of chromium with -O2 (but no icf,gc) from
1.940664632 to 1.925578119.

llvm-svn: 268639
2016-05-05 16:12:25 +00:00
Peter Collingbourne e29e142a10 ELF: Do not use -1 to mark pieces of merge sections as being tail merged.
We were previously using an output offset of -1 for both GC'd and tail
merged pieces. We need to distinguish these two cases in order to filter
GC'd symbols from the symbol table -- we were previously asserting when we
asked for the VA of a symbol pointing into a dead piece, which would end
up asking the tail merging string table for an offset even though we hadn't
initialized it properly.

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

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

llvm-svn: 268604
2016-05-05 04:10:12 +00:00
Rafael Espindola ebb04b9eb6 Simplify handling of hint relocations.
llvm-svn: 268501
2016-05-04 14:44:22 +00:00
Rafael Espindola de2c76ed73 Sort entries. NFC.
llvm-svn: 268499
2016-05-04 14:38:55 +00:00
Simon Atanasyan add74f37f2 [ELF][MIPS] Read/write .MIPS.options section
MIPS N64 ABI introduces .MIPS.options section which specifies miscellaneous
options to be applied to an object/shared/executable file. LLVM as well as
modern versions of GNU tools read and write the only type of the options -
ODK_REGINFO. It is exact copy of .reginfo section used by O32 ABI.

llvm-svn: 268485
2016-05-04 10:07:38 +00:00
Rafael Espindola a85efd985c Don't create dynamic relocations to ro segments.
These would just crash at runtime.

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

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

llvm-svn: 268149
2016-04-30 01:15:17 +00:00
Rui Ueyama 2b6fb80384 Skip scanRelocs for non-alloc sections.
Relocations against sections with no SHF_ALLOC bit are R_ABS relocations.
Currently we are creating Relocations vector for them, but that is wasteful.
This patch is to skip vector construction and to directly apply relocations
in place.

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

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

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

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

llvm-svn: 267917
2016-04-28 18:42:04 +00:00
Peter Collingbourne 676c7cd1ed ELF: Move code to where it is used, and related cleanups. NFC.
Differential Revision: http://reviews.llvm.org/D19490

llvm-svn: 267637
2016-04-26 23:52:44 +00:00