520 Commits

Author SHA1 Message Date
Rafael Espindola
b415e6b2f2 Centralize the handling of unique ids for temporary labels.
Before this patch code wanting to create temporary labels for a given entity
(function, cu, exception range, etc) had to keep its own counter to have stable
symbol names.

createTempSymbol would still add a suffix to make sure a new symbol was always
returned, but it kept a single counter. Because of that, if we were to use
just createTempSymbol("cu_begin"), the label could change from cu_begin42 to
cu_begin43 because some other code started using temporary labels.

Simplify this by just keeping one counter per prefix and removing the various
specialized counters.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232535 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 20:07:06 +00:00
Rafael Espindola
03b47b8e5b Remove dead code. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232472 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-17 13:09:01 +00:00
Duncan P. N. Exon Smith
3d5527fb43 IR: Take advantage of -verify checks for MDExpression
Now that we check `MDExpression` during `-verify` (r232299), make
the `DIExpression` wrapper more strict:

  - remove redundant checks in `DebugInfoVerifier`,
  - overload `get()` to `cast_or_null<MDExpression>` (superseding
    `getRaw()`),
  - stop checking for null in any accessor, and
  - remove `DIExpression::Verify()` entirely in favour of
    `MDExpression::isValid()`.

There is still some logic in this class, mostly to do with high-level
iterators; I'll defer cleaning up those until the rest of the wrappers
are similarly strict.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232412 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-16 21:03:55 +00:00
Rafael Espindola
658236dec2 Print section start labels when first switching to the section.
This is less brittle and avoids polluting the start of the file with every
debug section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231898 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-11 00:51:37 +00:00
Rafael Espindola
f3d745cdc9 Create symbols marking the start of a section earlier.
This lets us pass the symbol to the constructor and avoid the mutable field.

This also opens the way for outputting the symbol only when needed, instead
of outputting them at the start of the file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231859 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 22:00:25 +00:00
Rafael Espindola
0f4df6dc6f Store an optional section start label in MCSection.
This makes code that uses section relative expressions (debug info) simpler and
less brittle.

This is still a bit awkward as the symbol is created late and has to be
stored in a mutable field.

I will move the symbol creation earlier in the next patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231802 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 16:58:10 +00:00
Rafael Espindola
71653f3324 Remove effectively dead code.
Switching back and forth between sections does nothing (other than producing
larger .s files).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231790 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 14:48:01 +00:00
Rafael Espindola
304fe62b74 Use the existing begin and end symbol for debug info.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231338 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 02:05:42 +00:00
Paul Robinson
4ceab42509 Support standard DWARF TLS opcode; Darwin and PS4 use it.
Differential Revision: http://reviews.llvm.org/D8018


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231286 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 20:55:11 +00:00
Frederic Riss
79664f9749 Move emitDIE and emitAbbrevs to AsmPrinter. NFC.
(They are called emitDwarfDIE and emitDwarfAbbrevs in their new home)

llvm-dsymutil wants to reuse that code, but it doesn't have a DwarfUnit or
a DwarfDebug object to call those. It has access to an AsmPrinter though.

Having emitDIE in the AsmPrinter also removes the DwarfFile dependency
on DwarfDebug, and thus the patch drops that field.

Differential Revision: http://reviews.llvm.org/D8024

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231210 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 02:30:17 +00:00
Adrian Prantl
994176ad7c Refactor DebugLocDWARFExpression so it doesn't require access to the
TargetRegisterInfo. DebugLocEntry now holds a buffer with the raw bytes
of the pre-calculated DWARF expression.

Ought to be NFC, but it does slightly alter the output format of the
textual assembly.

This reapplies 230930 without the assertion in DebugLocEntry::finalize()
because not all Machine registers can be lowered into DWARF register
numbers and floating point constants cannot be expressed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231023 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 22:02:33 +00:00
Adrian Prantl
a2e69c9c58 Revert "Refactor DebugLocDWARFExpression so it doesn't require access to the"
This reverts commit 230975 to investigate buildbot breakage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231004 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 20:01:54 +00:00
Adrian Prantl
9680c9c1a8 Refactor DebugLocDWARFExpression so it doesn't require access to the
TargetRegisterInfo. DebugLocEntry now holds a buffer with the raw bytes
of the pre-calculated DWARF expression.

Ought to be NFC, but it does slightly alter the output format of the
textual assembly.

This reapplies 230930 with a relaxed assertion in DebugLocEntry::finalize()
that allows for empty DWARF expressions for constant FP values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230975 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 17:21:06 +00:00
Nico Weber
5e871d0b9c Revert r230930, it caused PR22747.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230932 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 04:37:11 +00:00
Adrian Prantl
d21acaf6a1 Refactor DebugLocDWARFExpression so it doesn't require access to the
TargetRegisterInfo. DebugLocEntry now holds a buffer with the raw bytes
of the pre-calculated DWARF expression.

Ought to be NFC, but it does slightly alter the output format of the
textual assembly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230930 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-02 02:38:18 +00:00
Rafael Espindola
4b2e78ecac Simplify arange output.
Move SectionMap to its only user (emitDebugARanges) and
reorder to save a call to sort.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230693 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 22:02:02 +00:00
Eric Christopher
cd3a8ad3e7 80-column fixups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229527 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-17 20:02:28 +00:00
Adrian Prantl
7b98f2d2a6 Debug Info: Support variables that are described by more than one MMI
table entry. This happens when SROA splits up an alloca and the resulting
allocas cannot be lowered to SSA values because their address is passed
to a function.

Fixes PR22502.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228764 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-10 23:18:28 +00:00
Chandler Carruth
1b279144ec [cleanup] Re-sort all the #include lines in LLVM using
utils/sort_includes.py.

I clearly haven't done this in a while, so more changed than usual. This
even uncovered a missing include from the InstrProf library that I've
added. No functionality changed here, just mechanical cleanup of the
include order.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225974 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-14 11:23:27 +00:00
Adrian Prantl
57ed5ffc76 Debug Info: Move the complex expression handling (=the remainder) of
emitDebugLocValue() into DwarfExpression.

Ought to be NFC, but it actually uncovered a bug in the debug-loc-asan.ll
testcase. The testcase checks that the address of variable "y" is stored
at [RSP+16], which also lines up with the comment.
It also check(ed) that the *value* of "y" is stored in RDI before that,
but that is actually incorrect, since RDI is the very value that is
stored in [RSP+16]. Here's the assembler output:

	movb	2147450880(%rcx), %r8b
	#DEBUG_VALUE: bar:y <- RDI
	cmpb	$0, %r8b
	movq	%rax, 32(%rsp)          # 8-byte Spill
	movq	%rsi, 24(%rsp)          # 8-byte Spill
	movq	%rdi, 16(%rsp)          # 8-byte Spill
.Ltmp3:
	#DEBUG_VALUE: bar:y <- [RSP+16]

Fixed the comment to spell out the correct register and the check to
expect an address rather than a value.

Note that the range that is emitted for the RDI location was and is still
wrong, it claims to begin at the function prologue, but really it should
start where RDI is first assigned.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225851 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 23:39:11 +00:00
Frederic Riss
0c36e97b78 Make DIE.h a public CodeGen header.
dsymutil would like to use all the AsmPrinter/MCStreamer infrastructure
to stream out the DWARF. In order to do so, it will reuse the DIE object
and so this header needs to be public.

The interface exposed here has some corners that cannot be used without a
DwarfDebug object, but clients that want to stream Dwarf can just avoid
these.

Differential Revision: http://reviews.llvm.org/D6695

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225208 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-05 21:29:41 +00:00
David Blaikie
41ebc263a9 Move cross-unit DIE caching to the DwarfFile level, so it doesn't interfere with fission-gmlt data and produce skeleton<>full unit cross referencing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221305 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 22:12:18 +00:00
David Blaikie
21cd65acf4 DebugInfo: Sink accelerator table lists down (GlobalNames/Types) into DwarfCompileUnit
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221083 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-02 06:16:39 +00:00
David Blaikie
153cd65fd4 Sink DwarfDebug::AbstractSPDies down into DwarfFile
This is the first big step to allowing gmlt-like inline scope
information in the skeleton CU. While this commit doesn't change the
functionality, it's only a small step to call
"constructAbstractSubprogramDIE" on both the InfoHolder and the
SkeletonHolder (when in use) and that will at least create the abstract
SP dies in that case, though still not creating the other subprograms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221051 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-01 17:21:26 +00:00
David Blaikie
7f6ba1758b DebugInfo: Sink DwarfDebug::ScopeVariables down into DwarfFile
(part of refactoring to allow subprogram emission in both the skeleton
and main units to enable -gmlt-like data to be included in the skeleton
for live inlined backtracing purposes)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220578 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-24 17:57:34 +00:00
David Blaikie
3ad7d41947 Remove DwarfDebug::FirstCU as it has no use
It was only being used as a flag to identify the lack of debug info from
within endModule - use the section labels for that instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220575 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-24 17:53:38 +00:00
David Blaikie
8a5eafb58d DebugInfo: Remove DwarfDebug::addScopeVariable now that it's just a trivial wrapper
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220542 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-24 00:43:47 +00:00
David Blaikie
991327143f DebugInfo: Remove DwarfDebug::CurrentFnArguments since we have to handle argument ordering of other arguments (abstract arguments) in the same way and already have code for that too.
While refactoring this code I was confused by both the name I had
introduced (addNonArgumentVariable... but it has all this logic to
handle argument numbering and keep things in order?) and by the
redundancy. Seems when I fixed the misordered inlined argument handling,
I didn't realize it was mostly redundant with the argument ordering code
(which I may've also written, I'm not sure). So let's just rely on the
more general case.

The only oddity in output this produces is that it means when we emit
all the variables for the current function, we don't track when we've
finished the argument variables and are about to start the local
variables and insert DW_AT_unspecified_parameters (for varargs
functions) there. Instead it ends up after the local variables, scopes,
etc. But this isn't invalid and doesn't cause DWARF consumers problems
that I know of... so we'll just go with that because it makes the code
nice & simple.

(though, let's see what the buildbots have to say about this - *crosses
fingers*)

There will be some cleanup commits to follow to remove the now trivial
wrappers, etc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220527 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 22:27:50 +00:00
David Blaikie
48ba51a8cd DebugInfo: Sink DwarfDebug::addNonArgumentScopeVariable into DwarfFile.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220520 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 22:04:30 +00:00
David Blaikie
78f043e90a DebugInfo: Remove DwarfDebug::addCurrentFnArgument declaration now that it's moved to DwarfFile.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220515 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 21:53:17 +00:00
David Blaikie
ee129ed18d [DebugInfo] Remove LexicalScopes::isCurrentFunctionScope and CSE a use of LexicalScopes::getCurrentFunctionScope
Now that we're sure the only root (non-abstract) scope is the current
function scope, there's no need for isCurrentFunctionScope, the property
can be tested directly instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220451 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 00:06:27 +00:00
David Blaikie
68084538cb Simplify a few uses of DwarfDebug::SPMap
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219510 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-10 16:59:52 +00:00
David Blaikie
127cb8e873 Remove unused parameter
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219440 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 20:36:27 +00:00
David Blaikie
db0ec65e79 Sink DwarfDebug::createAndAddScopeChildren down into DwarfCompileUnit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219437 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 20:26:15 +00:00
David Blaikie
7cb5e0f56d Sink DwarfDebug::constructSubprogramScopeDIE down into DwarfCompileUnit
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219436 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 20:21:36 +00:00
David Blaikie
5465cc6741 Sink DwarfDebug::createScopeChildrenDIE down into DwarfCompileUnit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219422 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 18:24:28 +00:00
David Blaikie
12a37fc6e0 Sink DwarfDebug::constructLexicalScopeDIE into DwarfCompileUnit
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219414 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 17:08:42 +00:00
David Blaikie
3fcb9f3ea5 Sink DwarfDebug::constructInlinedScopeDIE into DwarfCompileUnit
This introduces access to the AbstractSPDies map from DwarfDebug so
DwarfCompileUnit can access it. Eventually this'll sink down to
DwarfFile, but it'll still be generically accessible - not much
encapsulation to provide it. (constructInlinedScopeDIE could stay
further up, in DwarfFile to avoid exposing this - but I don't think
that's particularly better)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219411 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 16:50:53 +00:00
David Blaikie
7ed0e6d0c6 Push DwarfDebug::attachRangesOrLowHighPC down into DwarfCompileUnit
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219372 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 00:21:42 +00:00
David Blaikie
cbb705d900 Sink DwarfDebug::addScopeRangeList down into DwarfCompileUnit
(& add a few accessors/make a couple of things public for this - it's a
bit of a toss-up, but I think I prefer it this way, keeping some more of
the meaty code down in DwarfCompileUnit - if only to make for smaller
implementation files, etc)

I think we could simplify range handling a bit if we removed the range
lists from each unit and just put a single range list on DwarfDebug,
similar to address pooling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219370 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 00:11:39 +00:00
David Blaikie
f616a4ba06 Reformat some stuff I missed in recent previous commits
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219356 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 23:09:42 +00:00
David Blaikie
3e9c8c557b DebugInfo: The rest of pushing DwarfDebug::constructScopeDIE down into DwarfCompileUnit
Funnily enough, I copied it, but didn't actually remove the original in
r219345. Let's do that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219346 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 22:23:10 +00:00
David Blaikie
3f2f9695c5 Push DwarfDebug::constructScopeDIE down into DwarfCompileUnit
One of many steps to generalize subprogram emission to both the DWO and
non-DWO sections (to emit -gmlt-like data under fission). Once the
functions are pushed down into DwarfCompileUnit some of the data
structures will be pushed at least into DwarfFile so that they can be
unique per-file, allowing emission to both files independently.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219345 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 22:20:02 +00:00
David Blaikie
d53f7f4b22 DebugInfo: Sink constructImportedEntityDIE down into DwarfUnit from DwarfDebug.
It was just calling a bunch of DwarfUnit functions anyway, as can be
seen by the simplification of removing "TheCU" from all the function
calls in the implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219103 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-06 05:37:24 +00:00
David Blaikie
446817b4ef Remove unused map
This became unnecessary/unused in r208636

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219085 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-05 16:31:13 +00:00
David Blaikie
53b95f3fb1 Sink DwarfDebug::updateSubprogramScopeDIE into DwarfCompileUnit
This requires exposing some of the current function state from
DwarfDebug. I hope there's not too much of that to expose as I go
through all the functions, but it still seems nicer to expose singular
data down to multiple consumers, than have consumers expose raw mapping
data structures up to DwarfDebug for building subprograms.

Part of a series of refactoring to allow subprograms in both the
skeleton and dwo CUs under Fission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219060 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-04 16:24:00 +00:00
David Blaikie
2c9ba7b7b1 Sink DwarfDebug::attachLowHighPC into DwarfCompileUnit
One of many things to sink down into DwarfCompileUnit to allow handling
of subprograms in both the skeleton and dwo CU under Fission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219058 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-04 15:58:47 +00:00
Adrian Prantl
02474a32eb Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

Note: I accidentally committed a bogus older version of this patch previously.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218787 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-01 18:55:02 +00:00
Adrian Prantl
10c4265675 Revert r218778 while investigating buldbot breakage.
"Move the complex address expression out of DIVariable and into an extra"

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218782 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-01 18:10:54 +00:00
Adrian Prantl
076fd5dfc1 Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218778 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-01 17:55:39 +00:00