Commit Graph

1561 Commits

Author SHA1 Message Date
Reid Kleckner
0737b4ee14 Rename EH related stuff to be more precise
Summary:
The current "WinEH" exception handling type is more about Itanium-style
LSDA tables layered on top of the Windows native unwind info format
instead of .eh_frame tables or EHABI unwind info. Use the name
"ItaniumWinEH" to better reflect the hybrid nature of the design.

Also rename isExceptionHandlingDWARF to usesItaniumLSDAForExceptions,
since the LSDA is part of the Itanium C++ ABI document, and not the
DWARF standard.

Reviewers: echristo

Subscribers: llvm-commits, compnerd

Differential Revision: http://reviews.llvm.org/D6279

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222062 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-14 23:31:07 +00:00
Justin Hibbits
fcd08c294a Add support for small-model PIC for PowerPC.
Summary:
Large-model was added first.  With the addition of support for multiple PIC
models in LLVM, now add small-model PIC for 32-bit PowerPC, SysV4 ABI.  This
generates more optimal code, for shared libraries with less than about 16380
data objects.

Test Plan: Test cases added or updated

Reviewers: joerg, hfinkel

Reviewed By: hfinkel

Subscribers: jholewinski, mcrosier, emaste, llvm-commits

Differential Revision: http://reviews.llvm.org/D5399

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221791 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-12 15:16:30 +00:00
NAKAMURA Takumi
23fc2a391d MCDisassembler::getInstruction():: Prune also "\param Region", since it was removed in r221751. [-Wdocumentation]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221775 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-12 07:42:26 +00:00
Rafael Espindola
6a222ec893 Pass an ArrayRef to MCDisassembler::getInstruction.
With this patch MCDisassembler::getInstruction takes an ArrayRef<uint8_t>
instead of a MemoryObject.

Even on X86 there is a maximum size an instruction can have. Given
that, it seems way simpler and more efficient to just pass an ArrayRef
to the disassembler instead of a MemoryObject and have it do a virtual
call every time it wants some extra bytes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221751 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-12 02:04:27 +00:00
Rafael Espindola
26dd2205ba Add const. NFC.
This adds const to a few methods that already return const references or
creates a const version when they reterun non-const references.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221666 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 05:11:47 +00:00
Rafael Espindola
6d5452d2d6 Don't duplicate names in comments. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221665 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 04:58:32 +00:00
Rafael Espindola
3959002c51 Don't repeat name in comment. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221664 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 04:49:14 +00:00
Rafael Espindola
d2c5947a4c Fix variable names and comment style. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221608 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-10 16:31:06 +00:00
Zoran Jovanovic
0f0a134d9d [mips][microMIPS] Mark symbols as microMIPS if necessary
Differential Revision: http://reviews.llvm.org/D6039


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221355 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 16:35:20 +00:00
Oliver Stannard
25f4c35b22 Revert r221150, as it broke sanitizer tests
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221151 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 12:19:03 +00:00
Oliver Stannard
b63d71ef81 Emit .eh_frame with relocations to functions, rather than sections
When LLVM emits DWARF call frame information, it currently creates a local,
section-relative symbol in the code section, which is pointed to by a
relocation on the .eh_frame section. However, for C++ we emit some functions in
section groups, and the SysV ABI has some rules to make it easier to remove
these sections
(http://www.sco.com/developers/gabi/latest/ch4.sheader.html#section_group_rules):

  A symbol table entry with STB_LOCAL binding that is defined relative to one
  of a group's sections, and that is contained in a symbol table section that is
  not part of the group, must be discarded if the group members are discarded.
  References to this symbol table entry from outside the group are not allowed.

This means that we need to use the function symbol for the relocation, not a
temporary symbol.

There was a comment in the code claiming that the local symbol was used to
avoid creating a relocation, but a relocation must be created anyway as the
code and CFI are in different sections.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221150 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 12:02:51 +00:00
Derek Schuff
cdb105b62f [MC] Attach labels to existing fragments instead of using a separate fragment
Summary:
Currently when emitting a label, a new data fragment is created for it if the
current fragment isn't a data fragment.
This change instead enqueues the label and attaches it to the next fragment
(e.g. created for the next instruction) if possible.

When bundle alignment is not enabled, this has no functionality change (it
just results in fewer extra fragments being created). For bundle alignment,
previously labels would point to the beginning of the bundle padding instead
of the beginning of the emitted instruction. This was not only less efficient
(e.g. jumping to the nops instead of past them) but also led to miscalculation
of the address of the GOT (since MC uses a label difference rather than
emitting a "." symbol).

Fixes https://code.google.com/p/nativeclient/issues/detail?id=3982

Test Plan: regression test attached

Reviewers: jvoung, eliben

Subscribers: jfb, llvm-commits

Differential Revision: http://reviews.llvm.org/D5915

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220439 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 22:38:06 +00:00
Chad Rosier
fa16693864 [AArch64] Add support for the .inst directive.
This has been implement using the MCTargetStreamer interface as is done in the
ARM, Mips and PPC backends.

Phabricator: http://reviews.llvm.org/D5891
PR20964

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220422 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 20:35:57 +00:00
Rafael Espindola
4af7ead7bd Drop support for an old version of ld64 (from darwin 9).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220310 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 18:31:09 +00:00
Rafael Espindola
45968c54e9 Fix a bit of confusion about .set and produce more readable assembly.
Every target we support has support for assembly that looks like

a = b - c
.long a

What is special about MachO is that the above combination suppresses the
production of a relocation.

With this change we avoid producing the intermediary labels when they don't
add any value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220256 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 01:17:30 +00:00
Rafael Espindola
d8ee23f34c Add back commits r219835 and a fixed version of r219829.
The only difference from r219829 is using

getOrCreateSectionSymbol(*ELFSec)

instead of

GetOrCreateSymbol(ELFSec->getSectionName())

in ELFObjectWriter which causes us to use the correct section symbol even if
we have multiple sections with the same name.

Original messages:

r219829:
Correctly handle references to section symbols.

When processing assembly like

.long .text

we were creating a new undefined symbol .text. GAS on the other hand would
handle that as a reference to the .text section.

This patch implements that by creating the section symbols earlier so that
they are visible during asm parsing.

The patch also updates llvm-readobj to print the symbol number in the relocation
dump so that the test can differentiate between two sections with the same name.

r219835:
Allow forward references to section symbols.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220021 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-17 01:48:58 +00:00
Rafael Espindola
70a1be3f76 Revert commit r219835 and r219829.
Revert "Correctly handle references to section symbols."
Revert "Allow forward references to section symbols."

Rui found a regression I am debugging.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220010 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-17 01:06:02 +00:00
Rafael Espindola
ad04f5db82 Correctly handle references to section symbols.
When processing assembly like

.long .text

we were creating a new undefined symbol .text. GAS on the other hand would
handle that as a reference to the .text section.

This patch implements that by creating the section symbols earlier so that
they are visible during asm parsing.

The patch also updates llvm-readobj to print the symbol number in the relocation
dump so that the test can differentiate between two sections with the same name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219829 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 18:55:30 +00:00
Derek Schuff
279b5504a3 [MC] Make bundle alignment mode setting idempotent and support nested bundles
Summary:
Currently an error is thrown if bundle alignment mode is set more than once
per module (either via the API or the .bundle_align_mode directive). This
change allows setting it multiple times as long as the alignment doesn't
change.

Also nested bundle_lock groups are currently not allowed. This change allows
them, with the effect that the group stays open until all nests are exited,
and if any of the bundle_lock directives has the align_to_end flag, the
group becomes align_to_end.

These changes make the bundle aligment simpler to use in the compiler, and
also better match the corresponding support in GNU as.

Reviewers: jvoung, eliben

Differential Revision: http://reviews.llvm.org/D5801

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219811 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 17:10:04 +00:00
Rafael Espindola
90ce9f70e2 Simplify handling of --noexecstack by using getNonexecutableStackSection.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219799 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 16:12:52 +00:00
Rafael Espindola
b510f8d08c Move getNonexecutableStackSection up to the base ELF class.
The .note.GNU-stack section is not SystemZ/X86 specific.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219796 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 15:44:16 +00:00
Benjamin Kramer
b85e7ae9ab [Modules] Add some missing includes to make files compile stand-alone.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219592 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-12 22:49:26 +00:00
Benjamin Kramer
b1bba1a339 MC: Shrink MCSymbolRefExpr by only storing the bits we need.
32 -> 16 bytes on x86_64. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219574 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 17:57:27 +00:00
Benjamin Kramer
fedd0e2a21 MC: Bit pack MCSymbolData.
On x86_64 this brings it from 80 bytes to 64 bytes. Also make any member
variables private and clean up uses to go through the existing accessors.

NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219573 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 15:07:21 +00:00
Sanjay Patel
0575fb9479 don't repeat function name in comments
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219218 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 17:28:04 +00:00
Sanjay Patel
4658d7a23b typos
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219216 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 17:00:16 +00:00
Yuri Gorshenin
86e0844d1c [asan-asm-instrumentation] CFI directives are generated for .S files.
Summary: CFI directives are generated for .S files.

Reviewers: eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5520

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219199 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 11:03:09 +00:00
Hans Wennborg
7fcd5f8c89 MachObjectWriter: optimize the string table for common suffices
This is a follow-up to r207670 (ELF) and r218636 (COFF).

Differential Revision: http://reviews.llvm.org/D5622

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219126 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-06 17:05:19 +00:00
Daniel Sanders
61bc405795 [mips] Print warning when using register names not available in N32/64
Summary:
The register names t4-t7 are not available in the N32 and N64 ABIs.
This patch prints a warning, when those names are used in N32/64,
along with a fix-it with the correct register names.

Patch by Vasileios Kalintiris

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5272


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218989 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-03 15:37:37 +00:00
Hans Wennborg
4edcbaec90 WinCOFFObjectWriter: optimize the string table for common suffices
This is a follow-up from r207670 which did the same for ELF.

Differential Revision: http://reviews.llvm.org/D5530

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218636 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-29 22:43:20 +00:00
Matt Arsenault
78beaa5d02 Fixing missing C++ mode comment
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218612 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-29 15:55:18 +00:00
Ehsan Akhgari
e6f6980d5b ms-inline-asm: Fix parsing label names inside bracket expressions
Summary:
This fixes a couple of issues.  One is ensuring that AOK_Label rewrite
rules have a lower priority than AOK_Skip rules, as AOK_Skip needs to
be able to skip the brackets properly.  The other part of the fix ensures
that we don't overwrite Identifier when looking up the identifier, and
that we use the locally available information to generate the AOK_Label
rewrite in ParseIntelIdentifier.  Doing that in CreateMemForInlineAsm
would be problematic since the Start location there may point to the
beginning of a bracket expression, and not necessarily the beginning of
an identifier.

This also means that we don't need to carry around the InternlName field,
which helps simplify the code.

Test Plan: This will be tested on the clang side.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5445

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218270 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-22 20:40:36 +00:00
Ehsan Akhgari
a956b28d32 Make MCAsmParserSemaCallback::LookupInlineAsmLabel a pure virtual function
Summary:
r218229 made this function return a dummy nullptr in order to avoid
API breakage between clang/llvm.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5432

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218266 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-22 19:49:07 +00:00
Ehsan Akhgari
ffaafbe92d ms-inline-asm: Add a sema callback for looking up label names
The implementation of the callback in clang's Sema will return an
internal name for labels.

Test Plan: Will be tested in clang.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218229 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-22 02:21:35 +00:00
Yaron Keren
c63035aa56 Add and update reset() and doInitialization() methods to MC* and passes.
This enables reusing a PassManager instead of re-constructing it every time.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217948 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-17 09:25:36 +00:00
Joe Abbey
e9233b393a ARMAsmBackend uses a factory method to generate binary file format specific
objects.  There were a few FIXMEs in ARMAsmBackend.cpp suggesting the class
definitions should be in a separate file.  Starting with ARMAsmBackend, the
class definition has been put in a header file, and #includes reduced.  Each
sub-type of ARMAsmBackend is now in its own header file.

Derived types have been painted with a different color of bike-shed:

  s/DarwinARMAsmBackend/ARMAsmBackendDarwin/g
  s/ARMWinCOFFAsmBackend/ARMAsmBackendWinCOFF/g
  s/ELFARMAsmBackend/ARMAsmBackendELF/g

Finally, clang-format has been run across ARMAsmBackend.cpp



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217866 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-16 09:18:23 +00:00
Yuri Gorshenin
ca31084292 [asan-assembly-instrumentation] Added CFI directives to the generated instrumentation code.
Summary: [asan-assembly-instrumentation] Added CFI directives to the generated instrumentation code.

Reviewers: eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5189

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217482 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 09:45:49 +00:00
Reid Kleckner
b9cb76d3f3 MC Win64: Put unwind info for COMDAT code into the same COMDAT group
Summary:
This fixes a long standing issue where we would emit many little .text
sections and only one .pdata and .xdata section. Now we generate one
.pdata / .xdata pair per .text section and associate them correctly.

Fixes PR19667.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5181

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217176 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-04 17:42:03 +00:00
Benjamin Kramer
a80ff26688 Add override to overriden virtual methods, remove virtual keywords.
No functionality change. Changes made by clang-tidy + some manual cleanup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217028 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-03 11:41:21 +00:00
Sean Silva
73d86aa56a Nuke MCAnalysis.
The code is buggy and barely tested. It is also mostly boilerplate.
(This includes MCObjectDisassembler, which is the interface to that
functionality)

Following an IRC discussion with Jim Grosbach, it seems sensible to just
nuke the whole lot of functionality, and dig it up from VCS if
necessary (I hope not!).

All of this stuff appears to have been added in a huge patch dump (look
at the timeframe surrounding e.g. r182628) where almost every patch
seemed to be untested and not reviewed before being committed.
Post-review responses to the patches were never addressed. I don't think
any of it would have passed pre-commit review.

I doubt anyone is depending on this, since this code appears to be
extremely buggy. In limited testing that Michael Spencer and I did, we
couldn't find a single real-world object file that wouldn't crash the
CFG reconstruction stuff. The symbolizer stuff has O(n^2) behavior and
so is not much use to anyone anyway. It seemed simpler to remove them as
a whole. Most of this code is boilerplate, which is the only way it was
able to scrape by 60% coverage.

HEADSUP: Modules folks, some files I nuked were referenced from
include/llvm/module.modulemap; I just deleted the references. Hopefully
that is the right fix (one was a FIXME though!).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216983 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-02 22:32:20 +00:00
Hans Wennborg
fb9a3fb12d MCSchedule.h: fix VS2012 build after r216919
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216924 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-02 18:00:00 +00:00
Pete Cooper
6de6c6aae4 Change MCSchedModel to be a struct of statically initialized data.
This removes static initializers from the backends which generate this data, and also makes this struct match the other Tablegen generated structs in behaviour

Reviewed by Andy Trick and Chandler C

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216919 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-02 17:43:54 +00:00
David Blaikie
7bda613297 Correct unique_ptr passing in MCObjectDisassembler::setFallbackRegion
Rather than passing by lvalue reference, pass by value to ensure that
the caller provides an rvalue (and use move assignment, rather than
release+reset, to assign to the member variable)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216916 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-02 17:29:51 +00:00
Saleem Abdulrasool
0c1740ce1a MC: remove unnecessary enumeration prefix
This is an enum class, and will be appropriately prefixed, making the encoding
type prefix redundant.  No change to any uses as the use of this was not yet
introduced.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216893 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-01 23:48:29 +00:00
Craig Topper
24ae56d4c9 Fix some cases where StringRef was being passed by const reference. Remove const from some other StringRefs since its implicitly const already.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216820 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-30 16:48:02 +00:00
Alexey Samsonov
c5198dc17a Make isValidMCLOHType take unsigned instead of enum to avoid loading invalid enum values
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216797 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-29 22:34:28 +00:00
Robin Morisset
217b38e19a Fix typos in comments, NFC
Summary: Just fixing comments, no functional change.

Test Plan: N/A

Reviewers: jfb

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D5130

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216784 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-29 21:53:01 +00:00
Joerg Sonnenberger
a5718c69b4 Convert MC command line option for fatal assembler warnings into a
proper flag.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216471 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-26 18:39:50 +00:00
Quentin Colombet
0d15213307 Add isInsertSubreg property.
This patch adds a new property: isInsertSubreg and the related target hooks:
TargetIntrInfo::getInsertSubregInputs and
TargetInstrInfo::getInsertSubregLikeInputs to specify that a target specific
instruction is a (kind of) INSERT_SUBREG.

The approach is similar to r215394.

<rdar://problem/12702965>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216139 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-20 23:49:36 +00:00
Quentin Colombet
dac67649f2 Add isExtractSubreg property.
This patch adds a new property: isExtractSubreg and the related target hooks:
TargetIntrInfo::getExtractSubregInputs and
TargetInstrInfo::getExtractSubregLikeInputs to specify that a target specific
instruction is a (kind of) EXTRACT_SUBREG.

The approach is similar to r215394.

<rdar://problem/12702965>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216130 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-20 21:51:26 +00:00