Commit Graph

54 Commits

Author SHA1 Message Date
Lang Hames
61bd005d1b [RuntimeDyld] Track symbol visibility in RuntimeDyld.
RuntimeDyld symbol info previously consisted of just a Section/Offset pair. This
patch replaces that pair type with a SymbolInfo class that also tracks symbol
visibility. A new method, RuntimeDyld::getExportedSymbolLoadAddress, is
introduced which only returns a non-zero result for exported symbols. For
non-exported or non-existant symbols this method will return zero. The
RuntimeDyld::getSymbolAddress method retains its current behavior, returning
non-zero results for all symbols regardless of visibility.

No in-tree clients of RuntimeDyld are changed. The newly introduced
functionality will be used by the Orc APIs.

No test case: Since this patch doesn't modify the behavior for any in-tree
clients we don't have a good tool to test this with yet. Once Orc is in we can
use it to write regression tests that test these changes.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226341 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-16 23:13:56 +00:00
Lang Hames
216e532dc1 [MCJIT] Reapply r222828 and r222810-r222812 with fix for MSVC move-op issues.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222840 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-26 16:54:40 +00:00
Aaron Ballman
19afe67157 Reverting r222828 and r222810-r222812 as they broke the build on Windows.
http://bb.pgr.jp/builders/ninja-clang-i686-msc17-R/builds/11753

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222833 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-26 15:27:39 +00:00
Lang Hames
7acaefabf6 [MCJIT] Clean up RuntimeDyld's quirky object-ownership/modification scheme.
Previously, when loading an object file, RuntimeDyld (1) took ownership of the
ObjectFile instance (and associated MemoryBuffer), (2) potentially modified the
object in-place, and (3) returned an ObjectImage that managed ownership of the
now-modified object and provided some convenience methods. This scheme accreted
over several years as features were tacked on to RuntimeDyld, and was both
unintuitive and unsafe (See e.g. http://llvm.org/PR20722).

This patch fixes the issue by removing all ownership and in-place modification
of object files from RuntimeDyld. Existing behavior, including debugger
registration, is preserved.

Noteworthy changes include:

(1) ObjectFile instances are now passed to RuntimeDyld by const-ref.
(2) The ObjectImage and ObjectBuffer classes have been removed entirely, they
    existed to model ownership within RuntimeDyld, and so are no longer needed.
(3) RuntimeDyld::loadObject now returns an instance of a new class,
    RuntimeDyld::LoadedObjectInfo, which can be used to construct a modified
    object suitable for registration with the debugger, following the existing
    debugger registration scheme.
(4) The JITRegistrar class has been removed, and the GDBRegistrar class has been
    re-written as a JITEventListener.

This should fix http://llvm.org/PR20722 .



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222810 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-26 06:53:26 +00:00
Lang Hames
9f1eb4d913 [MCJIT] Const-ify the symbol lookup operations on RuntimeDyld.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217263 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-05 18:00:16 +00:00
David Blaikie
91c286e4ed unique_ptrify RuntimeDyld::Dyld
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217180 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-04 18:37:29 +00:00
David Blaikie
96a8ccfab7 unique_ptrify a bunch of stuff through RuntimeDyld::loadObject
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217065 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-03 19:48:09 +00:00
Lang Hames
daf061cf05 [MCJIT] Refactor and add stub inspection to the RuntimeDyldChecker framework.
This patch introduces a 'stub_addr' builtin that can be used to find the address
of the stub for a given (<file>, <section>, <symbol>) tuple. This address can be
used both to verify the contents of stubs (by loading from the returned address)
and to verify references to stubs (by comparing against the returned address).

Example (1) - Verifying stub contents:

Load 8 bytes (assuming a 64-bit target) from the stub for 'x' in the __text
section of f.o, and compare that value against the addres of 'x'.

# rtdyld-check: *{8}(stub_addr(f.o, __text, x) = x

Example (2) - Verifying references to stubs:

Decode the immediate of the instruction at label 'l', and verify that it's
equal to the offset from the next instruction's PC to the stub for 'y' in the
__text section of f.o (i.e. it's the correct PC-rel difference).

# rtdyld-check: decode_operand(l, 4) = stub_addr(f.o, __text, y) - next_pc(l)
l:
        movq    y@GOTPCREL(%rip), %rax

Since stub inspection requires cooperation with RuntimeDyldImpl this patch
pimpl-ifies RuntimeDyldChecker. Its implementation is moved in to a new class,
RuntimeDyldCheckerImpl, that has access to the definition of RuntimeDyldImpl.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213698 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-22 22:47:39 +00:00
Lang Hames
c3747f276a [RuntimeDyld] Add a framework for testing relocation logic in RuntimeDyld.
This patch adds a "-verify" mode to the llvm-rtdyld utility. In verify mode,
llvm-rtdyld will test supplied expressions against the linked program images
that it creates in memory. This scheme can be used to verify the correctness
of the relocation logic applied by RuntimeDyld.

The expressions to test will be read out of files passed via the -check option
(there may be more than one of these). Expressions to check are extracted from
lines of the form:
# rtdyld-check: <expression>

This system is designed to fit the llvm-lit regression test workflow. It is
format and target agnostic, and supports verification of images linked for
remote targets. The expression language is defined in
llvm/include/llvm/RuntimeDyldChecker.h . Examples can be found in
test/ExecutionEngine/RuntimeDyld.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211956 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-27 20:20:57 +00:00
David Blaikie
00121bb932 PR19553: Memory leak in RuntimeDyldELF::createObjectImageFromFile
This starts in MCJIT::getSymbolAddress where the
unique_ptr<object::Binary> is release()d and (after a cast) passed to a
single caller, MCJIT::addObjectFile.

addObjectFile calls RuntimeDyld::loadObject.
RuntimeDld::loadObject calls RuntimeDyldELF::createObjectFromFile

And the pointer is never owned at this point. I say this point, because
the alternative codepath, RuntimeDyldMachO::createObjectFile certainly
does take ownership, so this seemed like a good hint that this was a/the
right place to take ownership.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207580 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-29 21:52:46 +00:00
Juergen Ributzka
50c385683c [MCJIT] Check if there have been errors during RuntimeDyld execution.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204837 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-26 18:19:27 +00:00
Lang Hames
20425d92df Add an option to MCJIT to have it forward all sections to the
RTDyldMemoryManager, regardless of whether it thinks they're "required for
execution".

Currently, RuntimeDyld only passes sections that are "required for execution"
to the RTDyldMemoryManager, and takes "required for execution" to mean exactly
"contains symbols or relocations". There are two problems with this:
(1) It can drop sections with anonymous data that is referenced by code.
(2) It leaves the JIT client no way to inspect interesting sections that aren't
    actually required to run the program (e.g dwarf sections).

A test case is still in the works.

Future work: We may want to replace this with a generic section filtering
mechanism, but that will require more consideration. For now, this flag at least
allows clients to volunteer to do the filtering themselves.

Fixes <rdar://problem/15177691>.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204398 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 21:06:46 +00:00
Lang Hames
42fdb1f00f Re-apply r196639: Add support for archives and object file caching under MCJIT.
I believe the bot failures on linux systems were due to overestimating the
alignment of object-files within archives, which are only guaranteed to be
two-byte aligned. I have reduced the alignment in
RuntimeDyldELF::createObjectImageFromFile accordingly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198737 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-08 04:09:09 +00:00
Lang Hames
a49701db7d Revert r196639 while I investigate a bot failure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196641 91177308-0d34-0410-b5e6-96231b3b80d8
2013-12-07 04:25:19 +00:00
Lang Hames
e7777cdc64 Add support for archives and object file caching under MCJIT.
Patch by Andy Kaylor, with minor edits to resolve merge conflicts.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196639 91177308-0d34-0410-b5e6-96231b3b80d8
2013-12-07 03:05:51 +00:00
Andrew Kaylor
43507d026b Adding support for deregistering EH frames with MCJIT.
Patch by Yaron Keren



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192753 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-16 00:14:21 +00:00
Andrew Kaylor
528f6d787b Adding multiple object support to MCJIT EH frame handling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192504 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-11 21:25:48 +00:00
Filip Pizlo
a4ea4a7203 Put RTDyldMemoryManager into its own file, and make it linked into
libExecutionEngine. Move method implementations that aren't specific to 
allocation out of SectionMemoryManager and into RTDyldMemoryManager.

This is in preparation for exposing RTDyldMemoryManager through the C 
API.

This is a fixed version of r182407 and r182411. That first revision 
broke builds because I forgot to move the conditional includes of 
various POSIX headers from SectionMemoryManager into 
RTDyldMemoryManager. Those includes are necessary because of how 
getPointerToNamedFunction works around the glibc libc_nonshared.a thing. 
The latter revision still broke things because I forgot to include 
llvm/Config/config.h.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182418 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-21 20:24:07 +00:00
Filip Pizlo
50f19a906a Roll out r182411 and 182412 because it's still broken.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182415 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-21 20:17:14 +00:00
Filip Pizlo
876af64ac7 Put RTDyldMemoryManager into its own file, and make it linked into
libExecutionEngine. Move method implementations that aren't specific to 
allocation out of SectionMemoryManager and into RTDyldMemoryManager.

This is in preparation for exposing RTDyldMemoryManager through the C 
API.

This is a fixed version of r182407. That revision broke builds because I 
forgot to move the conditional includes of various POSIX headers from 
SectionMemoryManager into RTDyldMemoryManager. Those includes are 
necessary because of how getPointerToNamedFunction works around the 
glibc libc_nonshared.a thing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182411 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-21 20:07:12 +00:00
Filip Pizlo
1441bf7a41 Roll out r182407 and r182408 because they broke builds.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182409 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-21 20:03:01 +00:00
Filip Pizlo
3bcc3e6f63 Put RTDyldMemoryManager into its own file, and make it linked into
libExecutionEngine. Move method implementations that aren't specific to 
allocation out of SectionMemoryManager and into RTDyldMemoryManager.

This is in preparation for exposing RTDyldMemoryManager through the C 
API.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182407 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-21 19:56:00 +00:00
David Tweed
abb38fe8de Minor changes to the MCJITTest unittests to use the correct API for finalizing
the JIT object (including XFAIL an ARM test that now needs fixing). Also renames
internal function for consistency.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182085 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-17 10:01:46 +00:00
Rafael Espindola
a2e40fbd62 Add EH support to the MCJIT.
This gets exception handling working on ELF and Macho (x86-64 at least).
Other than the EH frame registration, this patch also implements support
for GOT relocations which are used to locate the personality function on
MachO.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181167 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-05 20:43:10 +00:00
Jakub Staszak
674be02d52 Fix include guards so they exactly match file names.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172025 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-10 00:45:19 +00:00
Andrew Kaylor
8213068f34 Fix comment formatting in RuntimeDyld.h
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168739 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 22:53:57 +00:00
Andrew Kaylor
53608a34ce Interface changes to allow RuntimeDyld memory managers to set memory permissions after an object has been loaded.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168114 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-15 23:50:01 +00:00
Andrew Kaylor
647d6d7d3b Streamlined memory manager hierarchy for MCJIT and RuntimeDyld.
Patch by Ashok Thirumurthi

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167192 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-01 00:46:04 +00:00
Eric Christopher
9ed6da49f3 Spacing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166074 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 23:46:19 +00:00
Andrew Kaylor
3f23cef24f Clean-up of memory buffer and object ownership model in MCJIT
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165053 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-02 21:18:39 +00:00
Craig Topper
c2945e44d5 Mark unimplemented copy constructors and copy assignment operators as LLVM_DELETED_FUNCTION.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164090 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 02:01:41 +00:00
Jim Grosbach
e940c1bb6c Better const handling for RuntimeDyld and MCJIT.
mapSectionAddress() wasn't consistent.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163843 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-13 21:50:06 +00:00
Jim Grosbach
35ed842773 MCJIT: getPointerToFunction() references target address space.
Make sure to return a pointer into the target memory, not the local memory.
Often they are the same, but we can't assume that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163217 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-05 16:50:40 +00:00
Eli Bendersky
5fe019835c Fix some formatting, grammar and style issues and add a couple of missing comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155793 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-29 12:40:47 +00:00
Danil Malyshev
0e4fa5ff36 Re-factored RuntimeDyLd:
1. The main works will made in the RuntimeDyLdImpl with uses the ObjectFile class. RuntimeDyLdMachO and RuntimeDyLdELF now only parses relocations and resolve it. This is allows to make improvements of the RuntimeDyLd more easily. In addition the support for COFF can be easily added.

2. Added ARM relocations to RuntimeDyLdELF.

3. Added support for stub functions for the ARM, allowing to do a long branch.

4. Added support for external functions that are not loaded from the object files, but can be loaded from external libraries. Now MCJIT can correctly execute the code containing the printf, putc, and etc.

5. The sections emitted instead functions, thanks Jim Grosbach. MemoryManager.startFunctionBody() and MemoryManager.endFunctionBody() have been removed.
6. MCJITMemoryManager.allocateDataSection() and MCJITMemoryManager. allocateCodeSection() used JMM->allocateSpace() instead of JMM->allocateCodeSection() and JMM->allocateDataSection(), because I got an error: "Cannot allocate an allocated block!" with object file contains more than one code or data sections.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153754 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-30 16:45:19 +00:00
Bill Wendling
288967dfac Revert r153694. It was causing failures in the buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153701 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-29 23:23:59 +00:00
Danil Malyshev
4b0b8ef1b0 Re-factored RuntimeDyld.
Added ExecutionEngine/MCJIT tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153694 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-29 21:46:18 +00:00
Danil Malyshev
30b9e322e1 Move getPointerToNamedFunction() from JIT/MCJIT to JITMemoryManager.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153607 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-28 21:46:36 +00:00
Chandler Carruth
3e29671cca Revert a series of commits to MCJIT to get the build working in CMake
(and hopefully on Windows). The bots have been down most of the day
because of this, and it's not clear to me what all will be required to
fix it.

The commits started with r153205, then r153207, r153208, and r153221.
The first commit seems to be the real culprit, but I couldn't revert
a smaller number of patches.

When resubmitting, r153207 and r153208 should be folded into r153205,
they were simple build fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153241 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-22 05:44:06 +00:00
Danil Malyshev
799184d8eb Re-factored RuntimeDyld.
Added ExecutionEngine/MCJIT tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153221 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-21 21:06:29 +00:00
Danil Malyshev
6ae599a4a1 Missed getPointerToNamedFunction() declaration.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153207 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-21 18:47:10 +00:00
Jim Grosbach
020f4e861a ExecutionEngine interface to re-map addresses for engines that support it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148264 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-16 23:50:55 +00:00
Jim Grosbach
61425c0a7f MCJIT support for non-function sections.
Move to a by-section allocation and relocation scheme. This allows
better support for sections which do not contain externally visible
symbols.

Flesh out the relocation address vs. local storage address separation a
bit more as well. Remote process JITs use this to tell the relocation
resolution code where the code will live when it executes.

The startFunctionBody/endFunctionBody interfaces to the JIT and the
memory manager are deprecated. They'll stick around for as long as the
old JIT does, but the MCJIT doesn't use them anymore.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148258 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-16 22:26:39 +00:00
Danil Malyshev
cf852dc49b Add to RuntimeDyld support different object formats
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135037 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-13 07:57:58 +00:00
Jim Grosbach
f8c1c8465f MCJIT lazy relocation resolution and symbol address re-assignment.
Add handling for tracking the relocations on symbols and resolving them.
Keep track of the relocations even after they are resolved so that if
the RuntimeDyld client moves the object, it can update the address and any
relocations to that object will be updated.

For our trival object file load/run test harness (llvm-rtdyld), this enables
relocations between functions located in the same object module. It should
be trivially extendable to load multiple objects with mutual references.

As a simple example, the following now works (running on x86_64 Darwin 10.6):


$ cat t.c
int bar() {
  return 65;
}

int main() {
  return bar();
}
$ clang t.c -fno-asynchronous-unwind-tables -o t.o -c
$ otool -vt t.o
t.o:
(__TEXT,__text) section
_bar:
0000000000000000  pushq %rbp
0000000000000001  movq  %rsp,%rbp
0000000000000004  movl  $0x00000041,%eax
0000000000000009  popq  %rbp
000000000000000a  ret
000000000000000b  nopl  0x00(%rax,%rax)
_main:
0000000000000010  pushq %rbp
0000000000000011  movq  %rsp,%rbp
0000000000000014  subq  $0x10,%rsp
0000000000000018  movl  $0x00000000,0xfc(%rbp)
000000000000001f  callq 0x00000024
0000000000000024  addq  $0x10,%rsp
0000000000000028  popq  %rbp
0000000000000029  ret
$ llvm-rtdyld t.o -debug-only=dyld ; echo $?
Function sym: '_bar' @ 0
Function sym: '_main' @ 16
Extracting function: _bar from [0, 15]
    allocated to 0x100153000
Extracting function: _main from [16, 41]
    allocated to 0x100154000
Relocation at '_main' + 16 from '_bar(Word1: 0x2d000000)
Resolving relocation at '_main' + 16 (0x100154010) from '_bar (0x100153000)(pcrel, type: 2, Size: 4).
loaded '_main' at: 0x100154000
65
$




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129388 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-12 21:20:41 +00:00
Jim Grosbach
7cbf92d1d9 Tidy up a bit now that we're using the MemoryManager interface.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129328 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-12 00:23:32 +00:00
Jim Grosbach
b027105fa5 Refactor MCJIT 32-bit section loading.
Teach 32-bit section loading to use the Memory Manager interface, just like
the 64-bit loading does. Tidy up a few other things here and there.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129138 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-08 17:31:24 +00:00
Jim Grosbach
c41ab789a0 RuntimeDyld should use the memory manager API.
Start teaching the runtime Dyld interface to use the memory manager API
for allocating space. Rather than mapping directly into the MachO object,
we extract the payload for each object and copy it into a dedicated buffer
allocated via the memory manager. For now, just do Segment64, so this works
on x86_64, but not yet on ARM.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128973 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-06 01:11:05 +00:00
Chandler Carruth
53c5e7b2e7 Make the virtual destructor out-of-line so we have a key function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128964 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 23:54:31 +00:00
Chandler Carruth
d36d42d4ac Provide an empty virtual destructor to go with the virtual methods in
this class. Clang was warning on this with -Wnon-virtual-dtor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128952 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 23:03:24 +00:00