Commit Graph

24580 Commits

Author SHA1 Message Date
Chandler Carruth
da49414c4b [TTI] Make the cost APIs in TargetTransformInfo consistently use 'int'
rather than 'unsigned' for their costs.

For something like costs in particular there is a natural "negative"
value, that of savings or saved cost. As a consequence, there is a lot
of code that subtracts or creates negative values based on cost, all of
which is prone to awkwardness or bugs when dealing with an unsigned
type. Similarly, we *never* want these values to wrap, as that would
cause Very Bad code generation (likely percieved as an infinite loop as
we try to emit over 2^32 instructions or some such insanity).

All around 'int' seems a much better fit for these basic metrics. I've
added asserts to ensure that at least the TTI interface never returns
negative numbers here. If we ever have a use case for negative numbers,
we can remove this, but this way a bug where someone used '-1' to
produce a 'very large' cost will be caught by the assert.

This passes all tests, and is also UBSan clean.

No functional change intended.

Differential Revision: http://reviews.llvm.org/D11741

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244080 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 18:08:10 +00:00
Pete Cooper
baa8ef1276 Move BB succ_iterator to be inside TerminatorInst. NFC.
To get the successors of a BB we currently do successors(BB) which
ultimately walks the successors of the BB's terminator.

This moves the iterator to TerminatorInst as thats what we're actually
using to do the iteration, and adds a member function to TerminatorInst
to allow us to iterate directly over successors given an instruction.

For example, we can now do

  for (auto *Succ : BI->successors())

instead of

  for (unsigned i = 0, e = BI->getNumSuccessors(); i != e; ++i)

Reviewed by Tobias Grosser.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244074 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 17:43:01 +00:00
Rafael Espindola
f1595fb549 Drop unnecessary static_cast.
ELFT::TargetEndianness already has the correct type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244032 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 11:53:59 +00:00
Eric Christopher
5aed14945c Temporarily revert r244012 while we see if it's really necessary.
Add a comment explaining the current theory as to why we'd need
the -lole32 on the link line.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244015 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 05:32:22 +00:00
Eric Christopher
6624be6911 Remove autoconf checks for sigsetjmp and siglongjmp as they appear to
be unused.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244014 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 04:50:46 +00:00
Eric Christopher
5420525438 Remove the apparently unused rand48 configure checks and associated m4.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244013 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 04:50:43 +00:00
Eric Christopher
0443765649 Remove obsolete configure check for libole32 as we don't appear to use
it anymore.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244012 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 04:50:40 +00:00
Eric Christopher
54e7362f18 Remove the unused header check for utime.h.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244011 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-05 04:50:37 +00:00
Benjamin Kramer
0d2030d07e [ArrayRef] Make copy use std::uninitialized_copy.
std::copy does not work for non-trivially copyable classes when we're
copying into uninitialized memory.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243995 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 15:52:56 +00:00
Sanjay Patel
f360983642 wrap OptSize and MinSize attributes for easier and consistent access (NFCI)
Create wrapper methods in the Function class for the OptimizeForSize and MinSize
attributes. We want to hide the logic of "or'ing" them together when optimizing
just for size (-Os).

Currently, we are not consistent about this and rely on a front-end to always set
OptimizeForSize (-Os) if MinSize (-Oz) is on. Thus, there are 18 FIXME changes here
that should be added as follow-on patches with regression tests.

This patch is NFC-intended: it just replaces existing direct accesses of the attributes
by the equivalent wrapper call.

Differential Revision: http://reviews.llvm.org/D11734



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243994 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 15:49:57 +00:00
Justin Bogner
c85a9b26cf Remove the configure and cmake checks for sys/wait.h
If we don't have sys/wait.h and we're on a unix system there's no way
that several of the llvm tools work at all. This includes clang.

Just remove the configure and cmake checks entirely - we'll get a
build error instead of building something broken now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243957 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 06:29:58 +00:00
Adam Nemet
9a9814fc15 [LAA] Remove unused pointer partition argument from addRuntimeCheck, NFC
This variant of addRuntimeCheck is only used now from the LoopVectorizer
which does not use this parameter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243955 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 05:16:20 +00:00
Chen Li
7b3ed76a63 Introduce enum value for previously defined metadata -- make.implicit
Summary: This patch adds enum value for an existing metadata type -- make.implicit. Using preassigned enum will be helpful to get compile time type checking and avoid string construction and comparison. The patch also changes uses of make.implicit from string metadata to enum metadata. There is no functionality change.

Reviewers: reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11698

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243954 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 04:41:34 +00:00
Chandler Carruth
d86ea34863 [UB] Fix another place where we would pass a null pointer to memcpy.
This too was found by UBSan. Down to 35 failures for me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243932 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 00:53:01 +00:00
Chandler Carruth
25daca787a [UB] Fix a nasty place where we would pass null pointers to memcpy.
This happens to work, but is not guaranteed to work. Indeed, most memcpy
interfaces in Linux-land annotate these arguments as nonnull, and GCC
and LLVM both can and do optimized based upon that. When they do so,
they might legitimately have miscompiled code calling this routine with
two valid iterators, 'nullptr' and 'nullptr'. There was even code doing
precisely this because StringRef().begin() and StringRef().end() both
produce null pointers.

This was found by UBSan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243927 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-04 00:44:07 +00:00
Adam Nemet
ea0f5e2108 [LAA] Remove unused needsAnyChecking(), NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243921 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 23:33:03 +00:00
Adam Nemet
f6b29bc36c [LoopVer] Remove unused needsRuntimeChecks(), NFC
The previous commits moved this functionality into the client.

Also remove the now unused member variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243920 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 23:32:57 +00:00
David Blaikie
5aac19286a Update/correct comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243910 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 22:33:50 +00:00
David Blaikie
c4423f0478 -Wdeprecated-clean: Fix cases of violating the rule of 5 in ways that are deprecated in C++11
Various value handles needed to be copy constructible and copy
assignable (mostly for their use in DenseMap). But to avoid an API that
might allow accidental slicing, make these members protected in the base
class and make derived classes final (the special members become
implicitly public there - but disallowing further derived classes that
might be sliced to the intermediate type).

Might be worth having a warning a bit like -Wnon-virtual-dtor that
catches public move/copy assign/ctors in classes with virtual functions.
(suppressable in the same way - by making them protected in the base,
and making the derived classes final) Could be fancier and only diagnose
them when they're actually called, potentially.

Also allow a few default implementations where custom implementations
(especially with non-standard return types) were implemented.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243909 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 22:30:24 +00:00
Derek Schuff
f96e27f256 Fix testing for end of stream in bitstream reader.
This fixes a bug found while working on the bitcode reader. In
particular, the method BitstreamReader::AtEndOfStream doesn't always
behave correctly when processing a data streamer. The method
fillCurWord doesn't properly set CurWord/BitsInCurWord if the data
streamer was already at eof, but GetBytes had not yet set the
ObjectSize field of the streaming memory object.

This patch fixes this problem, and provides a test to show that
this problem has been fixed.

Patch by Karl Schimpf.

Differential Revision: http://reviews.llvm.org/D11391

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243890 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 18:01:50 +00:00
Duncan P. N. Exon Smith
c61bc48acb DI: Disallow uniquable DICompileUnits
Since r241097, `DIBuilder` has only created distinct `DICompileUnit`s.
The backend is liable to start relying on that (if it hasn't already),
so make uniquable `DICompileUnit`s illegal and automatically upgrade old
bitcode.  This is a nice cleanup, since we can remove an unnecessary
`DenseSet` (and the associated uniquing info) from `LLVMContextImpl`.

Almost all the testcases were updated with this script:

    git grep -e '= !DICompileUnit' -l -- test |
    grep -v test/Bitcode |
    xargs sed -i '' -e 's,= !DICompileUnit,= distinct !DICompileUnit,'

I imagine something similar should work for out-of-tree testcases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243885 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 17:26:41 +00:00
Duncan P. N. Exon Smith
268a755585 Linker: Move distinct MDNodes instead of cloning
Instead of cloning distinct `MDNode`s when linking in a module, just
move them over.  The module linker destroys the source module, so the
old node would otherwise just be leaked on the context.  Create the new
node in place.  This also reduces the number of cloned uniqued nodes
(since it's less likely their operands have changed).

This mapping strategy is only correct when we're discarding the source,
so the linker turns it on via a ValueMapper flag, `RF_MoveDistinctMDs`.

There's nothing observable in terms of `llvm-link` output here: the
linked module should be semantically identical.

I'll be adding more 'distinct' nodes to the debug info metadata graph in
order to break uniquing cycles, so the benefits of this will partly come
in future commits.  However, we should get some gains immediately, since
we have a fair number of 'distinct' `DILocation`s being linked in.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243883 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 17:09:38 +00:00
Tobias Grosser
1c12df14a6 Allow derived DOTViewers to choose the functions to illustrate
Instead of always showing/printing all functions, a class derived from
the DOTViewer class can overwrite the set of functions that will be
processed.

This will be used (and tested) by Polly's scop viewers, but other users
can be imagined as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243881 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 16:37:12 +00:00
JF Bastien
ca0cc47046 Refactor AtomicExpand::expandAtomicRMWToCmpXchg into a standalone function.
Summary:
This is useful for PNaCl's `RewriteAtomics` pass. NaCl intrinsics don't exist for some of the more exotic RMW instructions, so by refactoring this function into its own, `RewriteAtomics` can share code rewriting those atomics with `AtomicExpand` while additionally saving a few cycles by generating the `cmpxchg` NaCl-specific intrinsic with the callback. Without this patch, `RewriteAtomics` would require two extra passes over functions, by first requiring use of the full `AtomicExpand` pass to just expand the leftover exotic RMWs and then running itself again to expand resulting `cmpxchg`s.

NFC

Reviewers: jfb

Subscribers: jfb, llvm-commits

Differential Revision: http://reviews.llvm.org/D11422

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243880 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 15:29:47 +00:00
Silviu Baranga
b65ab9a410 [TTI] Fix default costs for interleaved accesses
Summary:
Modify the cost calculation function for interleaved accesses
to use the target-specific costs for insert/extract element and
memory operations.

This better models the case where the backend can't match
the interleaved group, and we are forced to use a wide load
and shuffle vectors.

Interleaved accesses are not enabled by default, so this shouldn't
cause a performance change.

Reviewers: jmolloy

Subscribers: jmolloy, llvm-commits

Differential Revision: http://reviews.llvm.org/D11718

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243875 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 14:00:58 +00:00
John Brawn
583fe8f203 [GlobalMerge] Allow targets to enable merging of extern variables, NFC.
Adjust the GlobalMergeOnExternal option so that the default behaviour is to
do whatever the Target thinks is best. Explicitly enabled or disabling the
option will override this default.

Differential Revision: http://reviews.llvm.org/D10965


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243873 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 12:08:41 +00:00
Duncan P. N. Exon Smith
5bb95798bc AsmPrinter: Stop inheriting from DIE
Change `DIELoc` and `DIEBlock` to stop inheriting from `DIE`, instead
inheriting from `DIEValueList` to share the value storage API.  This
awkward bit of code-sharing was also fairly confusing: neither `DIELoc`
nor `DIEBlock` represents a `DIE`, so why would they inherit from it?

Aside from the API cleanup, this should improve debug info memory usage
in the backend, since it shaves five pointers off of every `DIELoc` and
`DIEBlock`.  I haven't bothered to measure the savings, though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243858 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-02 20:54:50 +00:00
Duncan P. N. Exon Smith
bc3c2c319c AsmPrinter: Change DIEValueList to a subclass of DIE, NFC
Rewrite `DIEValueList` as a subclass of `DIE`, renaming its API to match
`DIE`'s.  This is preparation for changing `DIEBlock` and `DIELoc` to
stop inheriting from `DIE` and inherit directly from `DIEValueList`.

I thought about leaving this as a has-a relationship (and changing
`DIELoc` and `DIEBlock` to also have-a `DIEValueList`), but that seemed
to require a fair bit more boilerplate and I think it needed more
changes to the `DwarfUnit` API than this will.

No functionality change intended here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243854 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-02 20:42:45 +00:00
Duncan P. N. Exon Smith
1e95eedbab Remove dead code, NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243853 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-02 20:40:05 +00:00
Andrew Wilkins
510a661596 Add support to set/get ordering for load/store from the C API
Summary: As per title

Reviewers: chandlerc, bogner, majnemer, axw

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11141

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243847 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-02 12:16:57 +00:00
Craig Topper
f03f83cfc0 Mark CompositeType::getTypeAtIndex as const. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243845 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 22:52:12 +00:00
Craig Topper
55afc08759 Mark Type::getPointerTo as const. Unfortunately, this requires a const_cast inside, but at least it makes all methods on Type const. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243844 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 22:20:31 +00:00
Craig Topper
e0582480a4 Merge the const and non-const Type::getScalarType to a const version that returns a non-const pointer. Since we don't put const on Types all places were already calling the non-const version.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243843 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 22:20:27 +00:00
Craig Topper
84bbcfe200 De-constify pointers to Type since they can't be modified. NFC
This was already done in most places a while ago. This just fixes the ones that crept in over time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243842 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 22:20:21 +00:00
Yaron Keren
83d21e9cb2 Provide move constructor to appease Visual C++.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243836 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 15:50:53 +00:00
Simon Atanasyan
e35d602838 [Mips] Support DT_MIPS_RLD_MAP_REL dynamic section tag in the llvm-readobj
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243833 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 12:02:02 +00:00
David Blaikie
0ef4b3cef4 Workaround some compilers that give a stricter throw spec to = default than implicit dtors
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243823 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 05:10:37 +00:00
David Blaikie
14ec817aea Missing formatting
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243821 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 04:42:53 +00:00
David Blaikie
299ab3d150 -Wdeprecated-clean: Fix cases of violating the rule of 5 in ways that are deprecated in C++11
Various targets use std::swap on specific MCAsmOperands (ARM and
possibly Hexagon as well). It might be helpful to mark those subclasses
as final, to ensure that the availability of move/copy operations can't
lead to slicing. (same sort of requirements as the non-vitual dtor -
protected or a final class)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243820 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-01 04:40:41 +00:00
Alex Lorenz
f5cf675376 AMDGPU/SI: Add implicit register operands in the correct order.
This commit fixes a bug in the class 'SIInstrInfo' where the implicit register
machine operands were added to a machine instruction in an incorrect order -
the implicit uses were added before the implicit defs.

I found this bug while working on moving the implicit register operand
verification code from the MIR parser to the machine verifier.

This commit also makes the method 'addImplicitDefUseOperands' in the machine
instruction class public so that it can be reused in the 'SIInstrInfo' class.

Reviewers: Matt Arsenault

Differential Revision: http://reviews.llvm.org/D11689


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243799 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 23:30:09 +00:00
Alex Lorenz
c198b23a4d MIR Parser: Report an error when a jump table entry is redefined.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243798 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 23:13:23 +00:00
David Blaikie
7c24e4d3c5 Fix an MSVC build break since it can't synthesize move ctors.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243792 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 21:47:07 +00:00
David Blaikie
d79f0dd3d4 Fix a GCC buildbot that seemed to be having trouble producing the implicit move ctor
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243791 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 21:47:04 +00:00
David Blaikie
be031d9158 Fix some formatting from a recent commit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243789 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 21:37:58 +00:00
David Blaikie
4c20864f94 -Wdeprecated-clean: Fix cases of violating the rule of 5 in ways that are deprecated in C++11
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243788 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 21:37:09 +00:00
David Blaikie
b4b38d65e6 -Wdeprecated-clean: Fix cases of violating the rule of 5 in ways that are deprecated in C++11
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243786 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 21:26:16 +00:00
Duncan P. N. Exon Smith
bf2040f00c DI: Remove DW_TAG_arg_variable and DW_TAG_auto_variable
Remove the fake `DW_TAG_auto_variable` and `DW_TAG_arg_variable` tags,
using `DW_TAG_variable` in their place Stop exposing the `tag:` field at
all in the assembly format for `DILocalVariable`.

Most of the testcase updates were generated by the following sed script:

    find test/ -name "*.ll" -o -name "*.mir" |
    xargs grep -l 'DILocalVariable' |
    xargs sed -i '' \
      -e 's/tag: DW_TAG_arg_variable, //' \
      -e 's/tag: DW_TAG_auto_variable, //'

There were only a handful of tests in `test/Assembly` that I needed to
update by hand.

(Note: a follow-up could change `DILocalVariable::DILocalVariable()` to
set the tag to `DW_TAG_formal_parameter` instead of `DW_TAG_variable`
(as appropriate), instead of having that logic magically in the backend
in `DbgVariable`.  I've added a FIXME to that effect.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243774 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 18:58:39 +00:00
David Majnemer
4c43d5bdfa Attempt to appease the MSVC build bots
They don't seem to care for initializing an ArrayRef with a
std::initializer_list.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243769 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 18:13:25 +00:00
David Majnemer
4a45f0871a New EH representation for MSVC compatibility
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support.  Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.

Differential Revision: http://reviews.llvm.org/D11097

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243766 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 17:58:14 +00:00
Duncan P. N. Exon Smith
aa50fa7c2f DI: Rewrite the DIBuilder local variable API
Replace the general `createLocalVariable()` with two more specific
functions: `createParameterVariable()` and `createAutoVariable()`, and
rewrite the documentation.

Besides cleaning up the API, this avoids exposing the fake DWARF tags
`DW_TAG_arg_variable` and `DW_TAG_auto_variable` to frontends, and is
preparation for removing them completely.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243764 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 17:55:53 +00:00