534 Commits

Author SHA1 Message Date
Peter Collingbourne
a29ff2e0f9 MC: Implement support for new .addrsig and .addrsig_sym directives.
Part of the address-significance tables proposal:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123514.html

Differential Revision: https://reviews.llvm.org/D47744

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337328 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-17 22:17:18 +00:00
Michael J. Spencer
56500c79d3 [MC] Add assembler support for .cg_profile.
Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:

.cg_profile a, b, 32
.cg_profile freq, a, 11
.cg_profile freq, b, 20

When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).

Differential Revision: https://reviews.llvm.org/D44965

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333823 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-02 16:33:01 +00:00
Peter Collingbourne
60fd99da88 MC: Introduce an ELF dwo object writer and teach llvm-mc about it.
Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47051

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332875 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 19:44:54 +00:00
Peter Collingbourne
4ef1841f20 MC: Extract a derived class from ELFObjectWriter. NFCI.
This class will be used to create regular, non-split ELF files.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47049

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332870 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 19:30:59 +00:00
Peter Collingbourne
815bbef5d2 MC: Extract ELFObjectWriter's ELF writing functionality into an ELFWriter class. NFCI.
The idea is that we will be able to use this class to create multiple
files.

Differential Revision: https://reviews.llvm.org/D47048

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332867 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 19:18:28 +00:00
Peter Collingbourne
2e125e8f46 MC: Remove stream and output functions from MCObjectWriter. NFCI.
Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47043

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332864 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 18:28:57 +00:00
Peter Collingbourne
0d4292ff61 MC: Have the object writers return the number of bytes written. NFCI.
This removes the last external use of the stream.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47042

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332863 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 18:23:50 +00:00
Peter Collingbourne
8e93a9573f MC: Change object writers to use endian::Writer. NFCI.
Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47040

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332861 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 18:17:42 +00:00
Peter Collingbourne
74bda0b770 MC: Change MCAssembler::writeSectionData and writeFragmentPadding to take a raw_ostream. NFCI.
Also clean up a couple of hacks where we were writing the section
contents to another stream by setting the object writer's stream,
writing and setting it back.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47038

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332858 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 18:11:35 +00:00
Peter Collingbourne
a68d4cc279 Support: Simplify endian stream interface. NFCI.
Provide some free functions to reduce verbosity of endian-writing
a single value, and replace the endianness template parameter with
a field.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47032

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332757 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-18 19:46:24 +00:00
Peter Collingbourne
ec588866c6 MC: Remove dead code. NFCI.
We should never emit an SHT_DYNSYM into an object file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331821 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-08 22:59:05 +00:00
Sam Clegg
f21558f73a [MC] ELFObjectWriter: Removing unneeded variable and cast
Differential Revision: https://reviews.llvm.org/D46289

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331704 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-07 23:52:17 +00:00
Vlad Tsyrklevich
1e6776e94b ELFObjectWriter: Allow one unique symver per symbol
Summary:
Only allow a single unique .symver alias per symbol. This matches the
behavior of gas. I noticed that we ignored multiple mismatched symver
directives looking at https://reviews.llvm.org/D45798

Reviewers: pcc, tejohnson, espindola

Reviewed By: pcc

Subscribers: emaste, arichardson, llvm-commits, kcc

Differential Revision: https://reviews.llvm.org/D45845

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331078 91177308-0d34-0410-b5e6-96231b3b80d8
2018-04-27 20:32:34 +00:00
Rafael Espindola
6f0333acc1 Delay creating an alias for @@@.
With this we only create an alias for @@@ once we know if it should
use @ or @@. This avoids last minutes renames and hacks to handle MS
names.

This only handles the ELF writer. LTO still has issues with @@@
aliases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327160 91177308-0d34-0410-b5e6-96231b3b80d8
2018-03-09 18:42:25 +00:00
Lang Hames
e471346b60 [MC] Thread unique_ptr<MCObjectWriter> through the create.*ObjectWriter
functions.

This makes the ownership of the resulting MCObjectWriter clear, and allows us
to remove one instance of MCObjectStreamer's bizarre "holding ownership via
someone else's reference" trick.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315327 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-10 16:28:07 +00:00
Lang Hames
37437af14b [MC] Plumb unique_ptr<MCELFObjectTargetWriter> through createELFObjectWriter to
ELFObjectWriter's constructor.

Fixes the same ownership issue for ELF that r315245 did for MachO:
ELFObjectWriter takes ownership of its MCELFObjectTargetWriter, so we want to
pass this through to the constructor via a unique_ptr, rather than a raw ptr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315254 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-09 23:53:15 +00:00
Simon Atanasyan
cff5a9f329 [mips] Implement generation of relocations "chains" used by N32 ABI
In case of using a "nested" relocation expressions like this
`%hi(%neg(%gp_rel()))`, N32 ABI requires generation of three consecutive
relocations. That differs from the N64 ABI case where all relocations
are packed into the single relocation record.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313879 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-21 14:04:53 +00:00
Simon Atanasyan
fdc1645b20 [mips] Do not pass redundant IsN64 flag to MCELFObjectTargetWriter. NFC
Now we pass the 'Is64_' flag to the MCELFObjectTargetWriter ctor iif
when we make deal with N64 ABI. So it is redundant to pass additional
'IsN64' flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313878 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-21 14:04:47 +00:00
Rafael Espindola
210f522486 Simplify interface now that we don't need to pass IsPCRel. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307734 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-11 23:56:10 +00:00
Rafael Espindola
6f1c76b0b9 Add a common error checking for some invalid expressions.
This refactors a bit of duplicated code and fixes an assertion failure
on ELF.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306035 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-22 17:25:35 +00:00
Saleem Abdulrasool
e6be41f2a8 sink DebugCompressionType into MC for exposing to clang
This is a preparatory change to expose the debug compression style to
clang.  It requires exposing the enumeration and passing the actual
value through to the backend from the frontend in actual value form
rather than a boolean that selects the GNU style of debug info
compression.

Minor tweak to the ELF Object Writer to use a variable for re-used
values.  Add an assertion that debug information format is one of the
two currently known types if debug information is being compressed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305038 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-09 00:40:19 +00:00
Zachary Turner
19ca2b0f9d 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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304864 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-07 03:48:56 +00:00
Chandler Carruth
e3e43d9d57 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304787 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-06 11:49:48 +00:00
Eugene Zelenko
f49f90e97b [MC] Fix some Clang-tidy modernize-use-using warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301485 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-26 22:31:39 +00:00
Peter Collingbourne
b06c394fe3 MC: Remove unused virtual function MCObjectWriter::isWeak. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299817 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-08 23:35:49 +00:00
Evgeniy Stepanov
c67a9ef0ea Fix asm printing of associated sections.
Make MCSectionELF::AssociatedSection be a link to a symbol, because
that's how it works in the assembly, and use it in the asm printer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297769 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-14 19:28:51 +00:00
Vassil Vassilev
e9a37beafd Silence a warning "hiding virtual function".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297018 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-06 15:50:59 +00:00
Peter Collingbourne
6387bdabf7 MC: De-duplicate the object streamer implementations of EmitFileDirective into MCObjectStreamer. NFCI.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296912 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-03 21:22:06 +00:00
Eugene Zelenko
a700a60bfc [MC] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294813 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-11 00:27:28 +00:00
Rafael Espindola
5a2d92c7cf Make it possible to set SHF_LINK_ORDER explicitly.
This will make it possible to add support for gcing user metadata
(asan for example).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294589 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-09 14:59:20 +00:00
Rafael Espindola
7931a61c18 Change how we handle section symbols on ELF.
On ELF every section can have a corresponding section symbol. When in
an assembly file we have

.quad .text

the '.text' refers to that symbol.

The way we used to handle them is to leave .text an undefined symbol
until the very end when the object writer would map them to the
actual section symbol.

The problem with that is that anything before the end would see an
undefined symbol. This could result in bad diagnostics
(test/MC/AArch64/label-arithmetic-diags-elf.s), or incorrect results
when using the asm streamer (est/MC/Mips/expansion-jal-sym-pic.s).

Fixing this will also allow using the section symbol earlier for
setting sh_link of SHF_METADATA sections.

This patch includes a few hacks to avoid changing our behaviour when
handling conflicts between section symbols and other symbols. I
reported pr31850 to track that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293936 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-02 21:26:06 +00:00
George Rimar
ef935cd26f Recommit r292214 "[Support/Compression] - Change zlib API to return Error instead of custom status"
No any changes, will follow up with D28807 commit containing APLi change for clang
to fix build issues happened.

Original commit message:
[Support/Compression] - Change zlib API to return Error instead of custom status.

Previously API returned custom enum values.
Patch changes it to return Error with string description.
That should help users to report errors in universal way.

Differential revision: https://reviews.llvm.org/D28684



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292226 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 15:45:07 +00:00
George Rimar
7c0ccdc11d Revert r292214 "[Support/Compression] - Change zlib API to return Error instead of custom status."
It broked clang:
http://lab.llvm.org:8080/green//job/clang-stage1-cmake-RA-incremental_build/34218/consoleFull#46141505449ba4694-19c4-4d7e-bec5-911270d8a58c

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292217 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 13:27:58 +00:00
George Rimar
4a6a534c0c [Support/Compression] - Change zlib API to return Error instead of custom status.
Previously API returned custom enum values.
Patch changes it to return Error with string description.
That should help users to report errors in universal way.

Differential revision: https://reviews.llvm.org/D28684

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292214 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 13:20:17 +00:00
Saleem Abdulrasool
8edd5b452f MC: ensure that we have a section before accessing it
We would attempt to access the symbol section without ensuring that the symbol
was not absolute.  When the assembler referenced relocation is not evaluated to
the absolute, but when we record the relocation, we would query the section.
Because the symbol is absolute, it does not have a section associated with it,
triggering an assertion.  Just be more careful about the access of the section.

Addresses PR31064!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287619 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-22 04:32:54 +00:00
Rafael Espindola
2638e45e83 Misc improvements to StringTableBuilder.
This patch adds write methods to StringTableBuilder so that it is
easier to change the underlying implementation.

Using the write methods, avoid creating a temporary buffer when using
mmaped output.

It also uses a more compact key in the DenseMap. Overall this produces
a slightly faster lld:

firefox
  master 6.853419709
  patch  6.841968912 1.00167361138x faster
chromium
  master 4.297280174
  patch  4.298712163 1.00033323147x slower
chromium fast
  master 1.802335952
  patch  1.806872459 1.00251701521x slower
the gold plugin
  master 0.3247149
  patch  0.321971644 1.00852017888x faster
clang
  master 0.551279945
  patch  0.543733194 1.01387951128x faster
llvm-as
  master 0.032743458
  patch  0.032143478 1.01866568391x faster
the gold plugin fsds
  master 0.350814247
  patch  0.348571741 1.00643341309x faster
clang fsds
  master 0.6281672
  patch  0.621130222 1.01132931187x faster
llvm-as fsds
  master 0.030168899
  patch  0.029797155 1.01247582194x faster
scylla
  master 3.104222518
  patch  3.059590248 1.01458766252x faster

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283266 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-04 22:43:25 +00:00
Rafael Espindola
1963865e9d Delete some dead code.
Found by gcc 6.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273303 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-21 19:48:12 +00:00
George Rimar
ec285af61c Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.
Fix: updated clang code which was not updated by mistake.

Original commit message:
[llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.

This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)

Difference that this patch supports both zlib and zlib-gnu styles.

-compress-debug-sections option now supports next values:

-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.

Differential revision: http://reviews.llvm.org/D20676

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270987 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-27 12:27:32 +00:00
George Rimar
8ab5c74bc0 Revert r270977 ([llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.)
It broke buildbot:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/13585/steps/build/logs/stdio

Initial commit message:
[llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.

This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)

Difference that this patch supports both zlib and zlib-gnu styles.

-compress-debug-sections option now supports next values:

-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.

Differential revision: http://reviews.llvm.org/D20676

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270978 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-27 10:06:16 +00:00
George Rimar
dd4101a976 [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.
This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)

Difference that this patch supports both zlib and zlib-gnu styles.

-compress-debug-sections option now supports next values:

-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.

Differential revision: http://reviews.llvm.org/D20676

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270977 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-27 09:58:08 +00:00
Richard Smith
e89c000a82 Revert r270569 (teach llvm-mc to generate compressed debug sections in zlib
style). It appears that current ELF linkers are not ready for this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270638 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-25 00:14:12 +00:00
George Rimar
93b640c05d Recommit r270070 ([llvm-mc] - Teach llvm-mc to generate compressed debug sections in zlib style.)
Now, after landing r270560, r270557, r270320 it is a proper time.

Original commit message:
[llvm-mc] - Teach llvm-mc to generate compressed debug sections in zlib style.

Before this patch llvm-mc generated zlib-gnu styled sections. 
That means no SHF_COMPRESSED flag was set, magic 'zlib' signature
was used in combination with full size field. Sections were renamed to "*.z*".
This patch reimplements the compression style to zlib one as zlib-gnu looks
to be depricated everywhere.

Differential revision: http://reviews.llvm.org/D20331


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270569 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-24 15:19:35 +00:00
George Rimar
b29ea6447e Temporarily revert r270070
It broke buildbot:
http://lab.llvm.org:8011/builders/clang-s390x-linux/builds/4817/steps/ninja%20check%201/logs/stdio

Actually it is just because D20273 not yet commited, but these 2 were crossing with each other,
and I`ll better find the way to land them separatelly soon.

Initial commit message:

[llvm-mc] - Teach llvm-mc to generate compressed debug sections in zlib style.

Before this patch llvm-mc generated zlib-gnu styled sections. 
That means no SHF_COMPRESSED flag was set, magic 'zlib' signature
was used in combination with full size field. Sections were renamed to "*.z*".
This patch reimplements the compression style to zlib one as zlib-gnu looks
to be depricated everywhere.

Differential revision: http://reviews.llvm.org/D20331

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270075 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-19 15:58:05 +00:00
George Rimar
c9c693751f [llvm-mc] - Teach llvm-mc to generate compressed debug sections in zlib style.
Before this patch llvm-mc generated zlib-gnu styled sections. 
That means no SHF_COMPRESSED flag was set, magic 'zlib' signature
was used in combination with full size field. Sections were renamed to "*.z*".
This patch reimplements the compression style to zlib one as zlib-gnu looks
to be depricated everywhere.

Differential revision: http://reviews.llvm.org/D20331

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270070 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-19 15:08:31 +00:00
Daniel Sanders
134705a273 [mips] Correct the ordering of HI/LO pairs in the relocation table.
Summary:
There seems to have been a misunderstanding as to the meaning of 'offset' in
the rules laid down by our ABI. The previous code believed that 'offset' meant
the offset within the section that the relocation is applied to. However, it
should have meant the offset from the symbol used in the relocation expression.

This patch adds two fields to ELFRelocationEntry and uses them to correct the
order of relocations for MIPS. These fields contain:
* The original symbol before shouldRelocateWithSymbol() is considered. This
  ensures that R_MIPS_GOT16 is able to correctly distinguish between local and
  external symbols, allowing us to tell whether %got() requires a matching
  %lo() or not (local symbols require one, external symbols don't). It also
  prevents confusing cases where the fuzzy matching rules cause things like
  %hi(foo)/%lo(foo+3) and %hi(bar)/%lo(bar+1) to swap their %lo()'s.
* The original offset before shouldRelocateWithSymbol() is considered. The
  existing Addend field is always zero when the object uses in place addends
  (because it's already moved it to the encoding) but MIPS needs to use the
  original offset to ensure that the linker correctly calculates the carry-in
  bit for %hi() and %got().

IAS ensures that unmatchable %hi()/%got() relocations are placed at the end of
the table to ensure that the linker rejects the table (we're unable to report
such errors directly). The alternatives to this risk accidental matching
against inappropriate relocations which may silently compute incorrect values
due to an incorrect carry bit between the %lo() and %hi()/%got().

Reviewers: sdardis

Subscribers: dsanders, sdardis, rafael, llvm-commits

Differential Revision: http://reviews.llvm.org/D19718


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268733 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-06 13:49:25 +00:00
Daniel Sanders
c8b0a11468 [mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations.
Summary:
This is much closer to the way MIPS relocation expressions work
(%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the
various bodges in MipsAsmParser::evaluateRelocExpr().

Removing those bodges ensures that the constant stored in MCValue is the
full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used
to correct the %hi/%lo matching needed to sort the relocation table correctly.

As part of this:
* Gave MCExpr::print() the ability to omit parenthesis when emitting a
  symbol reference inside a MipsMCExpr operator like %hi(X). Without this
  we print things like %lo(($L1)).
* %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of
  the related special cases have been removed or moved to MipsMCExpr. We
  can remove the rest as we gain support for the less common relocations
  when they are not part of this specific combination.
* Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion
  with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_').
* fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical
  and merged into fixup_Mips_GOT.
* MO_GOT16 and MO_GOT turned out to be identical and have been merged into
  MO_GOT.
* VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they
  have been merged into MEK_GOT

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D19716


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268379 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-03 13:35:44 +00:00
David Blaikie
23d057905e [MC/ELFObjectWriter] Fix indentation of class body.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266136 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-12 21:45:53 +00:00
Evgeniy Stepanov
3828f99ca5 Handle section vs global name conflict.
This is a fix for PR26941.

When there is both a section and a global definition with the same
name, the global wins.

Section symbols are not added to the symbol table; section references
are left undefined and fixed up in the object writer unless they've
been satisfied by some other definition.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264649 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-28 20:36:28 +00:00
Eugene Zelenko
380d47d651 Fix Clang-tidy readability-redundant-control-flow warnings; other minor fixes.
Differential revision: http://reviews.llvm.org/D16793


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259539 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-02 18:20:45 +00:00
Rafael Espindola
888824fa23 Accept subtractions involving a weak symbol.
When a symbol S shows up in an expression in assembly there are two
possible interpretations
* The expression is referring to the value of S in this file.
* The expression is referring to the value after symbol resolution.

In the first case the assembler can reason about the value and try to
produce a relocation.
In the second case, that is only possible if the symbol cannot be
preempted.

Assemblers are not very consistent about which interpretation gets used.
This changes MC to agree with GAS in the case of an expression of the
form "Sym - WeakSym".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258329 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-20 18:57:48 +00:00