Commit Graph

735 Commits

Author SHA1 Message Date
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
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
Bob Wilson
b25dcfd104 Reserve some constant values for the Swift calling convention.
Swift has a custom calling convention that also requires some new flags
on arguments and one new attribute on alloca instructions. This patch
does not include the implementation of that calling convention - that
will be provided as part of the open-source release of Swift; this only
reserves the bitcode constant values so that they are not used for
other purposes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243379 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-28 04:05:45 +00:00
Igor Laevsky
6690dbffe0 Add argmemonly attribute.
This change adds new attribute called "argmemonly". Function marked with this attribute can only access memory through it's argument pointers. This attribute directly corresponds to the "OnlyAccessesArgumentPointees" ModRef behaviour in alias analysis.

Differential Revision: http://reviews.llvm.org/D10398



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241979 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-11 10:30:36 +00:00
James Molloy
ee0d992b07 Add support for fast-math flags to the FCmp instruction.
FCmp behaves a lot like a floating-point binary operator in many ways,
and can benefit from fast-math information. Flags such as nsz and nnan
can affect if this fcmp (in combination with a select) can be treated
as a fminnum/fmaxnum operation.

This adds backwards-compatible bitcode support, IR parsing and writing,
LangRef changes and IRBuilder changes. I'll need to audit InstSimplify
and InstCombine in a followup to find places where flags should be
copied.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241901 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 12:52:00 +00:00
David Majnemer
eddf9e2057 Revert the new EH instructions
This reverts commits r241888-r241891, I didn't mean to commit them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241893 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 07:15:17 +00:00
David Majnemer
751c4be705 New EH representation for MSVC compatibility
Summary:
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.

Reviewers: rnk, JosephTremoulet, reames, nlewycky, rjmccall

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11041

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241888 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 07:00:44 +00:00
Filipe Cabecinhas
177fabfc30 Remove always-true comparison, NFC.
Summary:
Looking at r241279, I noticed that UpgradedIntrinsics only gets written
to in the following code:

    if (UpgradeIntrinsicFunction(&F, NewFn))
      UpgradedIntrinsics[&F] = NewFn;

Looking through UpgradeIntrinsicFunction, we always return false OR
NewFn will be set to a different function from our source.

This patch pulls the F != NewFn into UpgradeIntrinsicFunction as an
assert, and removes the check from callers of UpgradeIntrinsicFunction.

Reviewers: rafael, chandlerc

Subscribers: llvm-commits-list

Differential Revision: http://reviews.llvm.org/D10915

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241369 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-03 20:12:01 +00:00
Rafael Espindola
21afba1004 Avoid a use after free.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241345 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-03 12:20:34 +00:00
Rafael Espindola
9afb3a2589 Fix for PR23310: llvm-dis crashes when trying to upgrade an intrinsic.
When trying to upgrade @llvm.x86.sse2.psrl.dq while parsing a module,
BitcodeReader adds the function to its worklist twice, resulting in a
crash when accessing it the second time.

This patch replaces the worklist vector by a map.

Patch by Philip Pfaffe.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241281 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-02 16:22:40 +00:00
Rafael Espindola
002ff89e22 Rangify some loops.
Patch by Philip Pfaffe!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241279 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-02 15:55:09 +00:00
Adrian Prantl
717764717b Add a DIModule metadata node to the IR.
It is meant to be used to record modules @imported by the current
compile unit, so a debugger an import the same modules to replicate this
environment before dropping into the expression evaluator.

DIModule is a sibling to DINamespace and behaves quite similarly.
In addition to the name of the module it also records the module
configuration details that are necessary to uniquely identify the module.
This includes the configuration macros (e.g., -DNDEBUG), the include path
where the module.map file is to be found, and the isysroot.

The idea is that the backend will turn this into a DW_TAG_module.

http://reviews.llvm.org/D9614
rdar://problem/20965932

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241017 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-29 23:03:47 +00:00
Alexander Kornienko
cd52a7a381 Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240390 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-23 09:49:53 +00:00
Rafael Espindola
21a540abc4 Remove the IsStreamed member variable.
Having different code paths for streamed and regular bitcode reading was a
source of bugs in the past and this defines them away.

It has a small but noticeable impact on performance. I timed running
"opt -disable-output -disable-verify" on a ltoed clang. It goes from

14.752845231 seconds time elapsed   ( +-  0.16% )

to

15.012463721 seconds time elapsed   ( +-  0.11% )

Extracted from a patch by Karl Schimpf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240305 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-22 18:06:15 +00:00
Alexander Kornienko
cf0db29df2 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240137 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-19 15:57:42 +00:00
David Majnemer
cc714e2142 Move the personality function from LandingPadInst to Function
The personality routine currently lives in the LandingPadInst.

This isn't desirable because:
- All LandingPadInsts in the same function must have the same
  personality routine.  This means that each LandingPadInst beyond the
  first has an operand which produces no additional information.

- There is ongoing work to introduce EH IR constructs other than
  LandingPadInst.  Moving the personality routine off of any one
  particular Instruction and onto the parent function seems a lot better
  than have N different places a personality function can sneak onto an
  exceptional function.

Differential Revision: http://reviews.llvm.org/D10429

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239940 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 20:52:32 +00:00
Rafael Espindola
cc625c9f25 Handle forward referenced function when streaming bitcode.
Without this the included unit test would assert in

  assert(BasicBlockFwdRefs.empty() && "Unresolved blockaddress fwd references");

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239871 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 01:15:47 +00:00
Rafael Espindola
485973a45e Handle MaterializeAll in getLazyBitcodeModuleImpl. NFC.
This just handles both cases in the same place.

Extracted from a patch by Karl Schimpf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239870 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 00:40:56 +00:00
Rafael Espindola
4a4558e436 Use std::unique_ptr to manage the DataStreamer in bitcode parsing.
We were already deleting it, this just makes it explicit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239867 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 23:29:49 +00:00
Rafael Espindola
20a6785cd2 Return a unique_ptr from getLazyBitcodeModule and parseBitcodeFile. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239858 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 22:27:55 +00:00
Rafael Espindola
0c650627ca Improve handling of end of file in the bitcode reader.
Before this patch the bitcode reader would read a module from a file
that contained in order:

* Any number of non MODULE_BLOCK sub blocks.
* One MODULE_BLOCK
* Any number of non MODULE_BLOCK sub blocks.
* 4 '\n' characters to handle OS X's ranlib.

Since we support lazy reading of modules, any information that is relevant
for the module has to be in the MODULE_BLOCK or before it. We don't gain
anything from checking what is after.

This patch then changes the reader to stop once the MODULE_BLOCK has been
successfully parsed.

This avoids the ugly special case for .bc files in an archive and makes it
easier to embed bitcode files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239845 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 20:03:39 +00:00
Peter Collingbourne
7ffec838a2 Protection against stack-based memory corruption errors using SafeStack
This patch adds the safe stack instrumentation pass to LLVM, which separates
the program stack into a safe stack, which stores return addresses, register
spills, and local variables that are statically verified to be accessed
in a safe way, and the unsafe stack, which stores everything else. Such
separation makes it much harder for an attacker to corrupt objects on the
safe stack, including function pointers stored in spilled registers and
return addresses. You can find more information about the safe stack, as
well as other parts of or control-flow hijack protection technique in our
OSDI paper on code-pointer integrity (http://dslab.epfl.ch/pubs/cpi.pdf)
and our project website (http://levee.epfl.ch).

The overhead of our implementation of the safe stack is very close to zero
(0.01% on the Phoronix benchmarks). This is lower than the overhead of
stack cookies, which are supported by LLVM and are commonly used today,
yet the security guarantees of the safe stack are strictly stronger than
stack cookies. In some cases, the safe stack improves performance due to
better cache locality.

Our current implementation of the safe stack is stable and robust, we
used it to recompile multiple projects on Linux including Chromium, and
we also recompiled the entire FreeBSD user-space system and more than 100
packages. We ran unit tests on the FreeBSD system and many of the packages
and observed no errors caused by the safe stack. The safe stack is also fully
binary compatible with non-instrumented code and can be applied to parts of
a program selectively.

This patch is our implementation of the safe stack on top of LLVM. The
patches make the following changes:

- Add the safestack function attribute, similar to the ssp, sspstrong and
  sspreq attributes.

- Add the SafeStack instrumentation pass that applies the safe stack to all
  functions that have the safestack attribute. This pass moves all unsafe local
  variables to the unsafe stack with a separate stack pointer, whereas all
  safe variables remain on the regular stack that is managed by LLVM as usual.

- Invoke the pass as the last stage before code generation (at the same time
  the existing cookie-based stack protector pass is invoked).

- Add unit tests for the safe stack.

Original patch by Volodymyr Kuznetsov and others at the Dependable Systems
Lab at EPFL; updates and upstreaming by myself.

Differential Revision: http://reviews.llvm.org/D6094

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239761 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:07:11 +00:00
Rafael Espindola
3aef7761ac Don't indent inside a namespace. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239760 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:04:27 +00:00
Rafael Espindola
132c3549d9 Replace @ with the more common \. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239759 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:02:49 +00:00
Rafael Espindola
9e26836221 Don't repeat names in comments and start functions with a lower case letter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239756 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 20:55:37 +00:00
Rafael Espindola
1456b12847 Cleanup the constructor of BitcodeReader. NFC.
Use the same argument names as the members.
Use default member initializes.

Extracted from a patch by Karl Schimpf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239749 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 20:08:17 +00:00
Yaron Keren
923bd1da56 Rangify two for loops in BitcodeReader.cpp.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239627 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-12 18:13:20 +00:00
Filipe Cabecinhas
ce986b6bc0 Use early return idiom. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239228 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-06 20:44:53 +00:00
Filipe Cabecinhas
a3a2cab504 [BitcodeReader] Diagnose type mismatches with aliases
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238895 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 01:30:13 +00:00
Filipe Cabecinhas
287f68d654 [BitcodeReader] Check vector size before trying to create a VectorType
Bug found with AFL fuzz

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238891 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 00:05:30 +00:00
Filipe Cabecinhas
3b821159da [BitcodeReader] Change an assert to a call to a call to Error()
It's reachable from user input.

Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238633 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-30 00:17:20 +00:00
Benjamin Kramer
9589ff8949 Replace push_back(Constructor(foo)) with emplace_back(foo) for non-trivial types
If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.


Call sites were found with the ASTMatcher + some semi-automated cleanup.

memberCallExpr(
    argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
    on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
    hasArgument(0, bindTemporaryExpr(
                       hasType(recordDecl(hasNonTrivialDestructor())),
                       has(constructExpr()))),
    unless(isInTemplateInstantiation()))

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238602 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-29 19:43:39 +00:00
Filipe Cabecinhas
1c0b496636 [BitcodeReader] Change assert to report_fatal_error
It can be triggered by user input.

Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238272 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-27 01:05:40 +00:00
Filipe Cabecinhas
316f9e05ce [BitstreamReader] Make sure the Array operand type is an encoding
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238269 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-27 00:48:43 +00:00
Filipe Cabecinhas
ba7ccd4201 clang-format a couple of lines
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238268 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-27 00:48:37 +00:00
Filipe Cabecinhas
c756772b8d [BitcodeReader] Make sure abbrev records have at least one operand (record code)
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238265 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-26 23:52:21 +00:00
Owen Anderson
13146c7e3b Add initial support for the convergent attribute.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238264 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-26 23:48:40 +00:00
Filipe Cabecinhas
1c74d4768a [BitcodeReader] Sanity check on Comdat ID
Shouldn't be an assert, since user input can trigger it.

Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238261 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-26 23:00:56 +00:00
Rafael Espindola
b9f5ce3a43 Simplify boolean conditional return statements.
Patch by Richard <legalize@xmission.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238134 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-25 13:50:21 +00:00
Adrian Prantl
849c7601a0 IR / debug info: Add a DWOId field to DICompileUnit,
so DWARF skeleton CUs can be expression in IR. A skeleton CU is a
(typically empty) DW_TAG_compile_unit that has a DW_AT_(GNU)_dwo_name and
a DW_AT_(GNU)_dwo_id attribute. It is used to refer to external debug info.

This is a prerequisite for clang module debugging as discussed in
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-November/040076.html.
In order to refer to external types stored in split DWARF (dwo) objects,
such as clang modules, we need to emit skeleton CUs, which identify the
dwarf object (i.e., the clang module) by filename (the SplitDebugFilename)
and a hash value, the dwo_id.

This patch only contains the IR changes. The idea is that a CUs with a
non-zero dwo_id field will be emitted together with a DW_AT_GNU_dwo_name
and DW_AT_GNU_dwo_id attribute.

http://reviews.llvm.org/D9488
rdar://problem/20091852

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237949 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-21 20:37:30 +00:00
Filipe Cabecinhas
bf27e11e02 [BitcodeReader] Error out if we read an invalid function argument type
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237650 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-19 01:21:06 +00:00
Filipe Cabecinhas
c3ccd67d72 [BitcodeReader] It's a malformed block if CodeLenWidth is too big
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237646 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-19 00:34:17 +00:00
Filipe Cabecinhas
b2bf278152 [BitcodeReader] Make sure the type of the inserted value matches the type of the aggregate at those indices
Bug found with AFL-fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237628 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-18 22:27:11 +00:00
Filipe Cabecinhas
70a2c7260a Extract the load/store type verification to a separate function.
Summary:
Added isLoadableOrStorableType to PointerType.

We were doing some checks in some places, occasionally assert()ing instead
of telling the caller. With this patch, I'm putting all type checking in
the same place for load/store type instructions, and verifying the same
thing every time.

I also added a check for load/store of a function type.

Applied extracted check to Load, Store, and Cmpxcg.

I don't have exhaustive tests for all of these, but all Error() calls in
TypeCheckLoadStoreInst are being tested (in invalid.test).

Reviewers: dblaikie, rafael

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9785

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237619 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-18 21:48:55 +00:00
Filipe Cabecinhas
ddf553bb8d [BitcodeReader] Don't allow INSERTVAL/EXTRACTVAL with 0 indices
This would trigger an assertion later.

Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237494 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-16 00:33:12 +00:00
Filipe Cabecinhas
6bde794d52 Remove redundant checks. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237488 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-15 23:57:13 +00:00
Eric Christopher
1bef1cdd92 While in GlobalValue fix the function(s) that don't follow the
naming convention and update users.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237461 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-15 18:20:14 +00:00
David Blaikie
66583e4917 [opaque pointer type] Explicit pointee type for GEPOperator/GEPConstantExpr.
Also a couple of other changes to avoid use of
PointerType::getElementType here & there too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236799 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-08 00:42:26 +00:00
Filipe Cabecinhas
deedba2a36 Don't overflow GCTable
Summary: Bug found with AFL fuzz.

Reviewers: rafael, dexonsmith

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9361

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236200 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-30 04:09:41 +00:00
Filipe Cabecinhas
8b2199e2a2 Make sure Op->getType() is a PointerType before we cast<> it.
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236193 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-30 01:13:31 +00:00