Commit Graph

258 Commits

Author SHA1 Message Date
Duncan P. N. Exon Smith 0e202b95c4 Verifier: Add operand checks for MDLexicalBlock
Add operand checks for `MDLexicalBlock` and `MDLexicalBlockFile`.  Like
`MDLocalVariable` and `MDLocation`, these nodes always require a scope.

There was no test bitrot to fix here (just updated the serialization
tests in test/Assembler/mdlexicalblock.ll).

llvm-svn: 233561
2015-03-30 16:37:48 +00:00
Duncan P. N. Exon Smith 869db50ffd Verifier: Check operands of MDSubprogram nodes
Check operands of `MDSubprogram`s in the verifier, and update the
accessors and factory functions to use more specific types.

There were a lot of broken testcases, which I fixed in r233466.  If you
have out-of-tree tests for debug info, you probably need similar changes
to the ones I made there.

llvm-svn: 233559
2015-03-30 16:19:15 +00:00
Duncan P. N. Exon Smith a8b3a1f374 Verifier: Allow subroutine types to have no type array
Loosen one check from r233446: as long as `DIBuilder` requires a
non-null type for every subprogram, we should allow a null type array.
Also add tests for the rest of `MDSubroutineType`, which were somehow
missing.

llvm-svn: 233468
2015-03-28 02:43:53 +00:00
Duncan P. N. Exon Smith 53855f05d3 Verifier: Check operands of MDType subclasses and MDCompileUnit
Add verify checks for `MDType` subclasses and for `MDCompileUnit`.
These new checks don't yet incorporate everything from `Verify()`, but
at least they sanity check the operands.  Also downcast accessors as
possible.

A lot of these accessors can't be downcast as far as we'd like because
of arrays of typed objects (stored in a generic `MDTuple`) and
`MDString`-based type references.  Eventually I'll port over `DIRef<>`
and `DITypedArray<>` from `DebugInfo.h` to clean those up as well.

Updated bitrotted testcases separately in r233415 and r233443 to reduce
churn on the off-chance this needs to be reverted.

llvm-svn: 233446
2015-03-27 23:05:04 +00:00
Duncan P. N. Exon Smith 3d2afaa29e Verifier: Check fields of MDVariable subclasses
Check fields from `MDLocalVariable` and `MDGlobalVariable` and change
the accessors to downcast to the right types.  `getType()` still returns
`Metadata*` since it could be an `MDString`-based reference.

Since local variables require non-null scopes, I also updated `LLParser`
to require a `scope:` field.

A number of testcases had grown bitrot and started failing with this
patch; I committed them separately in r233349.  If I just broke your
out-of-tree testcases, you're probably hitting similar problems (so have
a look there).

llvm-svn: 233389
2015-03-27 17:29:58 +00:00
Philip Reames e1bf27045d Require a GC strategy be specified for functions which use gc.statepoint
This was discussed a while back and I left it optional for migration.  Since it's been far more than the 'week or two' that was discussed, time to actually make this manditory.  

llvm-svn: 233357
2015-03-27 05:09:33 +00:00
David Majnemer b919dd693f WinEH: Create a parent frame alloca for HandlerType xdata tables
We don't have any logic to emit those tables yet, so the SDAG lowering
of this intrinsic is just a stub.  We can see the intrinsic in the
prepared IR, though.

llvm-svn: 233354
2015-03-27 04:17:07 +00:00
Duncan P. N. Exon Smith 264899823f Verifier: Check accessors of MDLocation
Check accessors of `MDLocation`, and change them to `cast<>` down to the
right types.  Also add type-safe factory functions.

All the callers that handle broken code need to use the new versions of
the accessors (`getRawScope()` instead of `getScope()`) that still
return `Metadata*`.  This is also necessary for things like
`MDNodeKeyImpl<MDLocation>` (in LLVMContextImpl.h) that need to unique
the nodes when their operands might still be forward references of the
wrong type.

In the `Value` hierarchy, consumers that handle broken code use
`getOperand()` directly.  However, debug info nodes have a ton of
operands, and their order (even their existence) isn't stable yet.  It's
safer and more maintainable to add an explicit "raw" accessor on the
class itself.

llvm-svn: 233322
2015-03-26 22:05:04 +00:00
Reid Kleckner 7e9546b378 WinEH: Create an unwind help alloca for __CxxFrameHandler3 xdata tables
We don't have any logic to emit those tables yet, so the sdag lowering
of this intrinsic is just a stub. We can see the intrinsic in the
prepared IR, though.

llvm-svn: 233209
2015-03-25 20:10:36 +00:00
Duncan P. N. Exon Smith fc25da101c Verifier: Start recursing into !dbg attachments
The main verifier already recurses through the other entry points, so we
might as well descend here too.

This temporarily duplicates some work already done in
`verifyDebugInfo()`, but eventually I'll be removing the other side.

llvm-svn: 233095
2015-03-24 17:32:19 +00:00
Duncan P. N. Exon Smith f238c78c4c Verifier: !llvm.dbg.cu must point at compile units
Duplicate this check from `verifyDebugInfo()`.

llvm-svn: 233094
2015-03-24 17:18:03 +00:00
Duncan P. N. Exon Smith a3bdc328a5 Verifier: Check that !dbg attachments have the right type
A WIP patch makes `DIDescriptor` accessors more strict, which in turn
causes the `DebugInfoFinder` to crash on wrongly typed `!dbg`
attachments.  Catch that error up front in
`Verifier::visitInstruction()`.

Also remove a test that we "handle" invalid `!dbg` attachments, added
back in r99938.  We don't want to handle those anymore.

Note: I'm *not* recursing and verifying the debug info graph reachable
from this node; that work is already done by `verifyDebugInfo()`.

llvm-svn: 232834
2015-03-20 19:26:58 +00:00
Duncan P. N. Exon Smith 8b866d1a6d Verifier: Remove the separate DebugInfoVerifier class
Remove the separate `DebugInfoVerifier` class, as a partial step toward
better integrating debug info verification with the `Verifier`.

Right now, verification of debug info is kind of a mess.

  - There are `DIDescriptor::Verify()` checks live in `DebugInfo.cpp`.
    These return `bool`, and there's no way to see (except by opening a
    debugger) why they fail.
  - We rely on `DebugInfoFinder` to traverse the debug info graph and
    dig up nodes.  However, the regular `Verifier` visits many of these
    nodes when it calls into debug info intrinsic operands.  Visiting
    twice and running different checks is kind of absurd.
  - Moreover, `DebugInfoFinder` asserts on failed type resolution -- the
    verifier should never assert!

By integrating the two verifiers, I'm aiming at solving these problems
(work to be done, obviously).  Verification can be localized to the
`Verifier`; we can use a naive `MDNode` operand traversal to find all
the nodes; we can verify type references instead of asserting on
failure.

There are `assert()`s sprinkled throughout the optimizer and dwarf
backend on `DIDescriptor::Verify()` checks.  This is a hangover from
when the debug info verifier was off, so I plan to remove them as I go
(once I confirm that the checks are done at verification time).

Note: to keep the behaviour of only running the debug info verifier when
-verify succeeds, I've added an `EverBroken` flag.  Once the
`DebugInfoFinder` assertions are gone and the two traversals have been
merged, I expect to be able to remove this.

llvm-svn: 232790
2015-03-20 00:48:23 +00:00
Duncan P. N. Exon Smith ab58a568ee Verifier: Remove the separate -verify-di pass
Remove `DebugInfoVerifierLegacyPass` and the `-verify-di` pass.
Instead, call into the `DebugInfoVerifier` from inside
`VerifierLegacyPass::finalizeModule()`.  This better matches the logic
in `verifyModule()` (used by the new PassManager), avoids requiring two
separate passes to verify the IR, and makes the API for "add a pass to
verify the IR" simple.

Note: the `-verify-debug-info` flag still works (for now, at least;
eventually it might make sense to just remove it).

llvm-svn: 232772
2015-03-19 22:24:17 +00:00
Duncan P. N. Exon Smith 719994b907 DebugInfo: Drop fake DW_TAG_expression
Break MDExpression off of DebugNode (inherit directly from `MDNode`) and
drop the fake `DW_TAG_expression` tag in the process.

AFAICT, there's no real functionality change here.  The tag was
originally used by `DIDescriptor::isExpression()` to discriminate
between `MDNode`s, but in the new hierarchy we don't need that.

Fixes PR22780.

llvm-svn: 232550
2015-03-17 21:32:46 +00:00
Duncan P. N. Exon Smith 0633fd7fb4 Verifier: Set --verify-debug-info=true by default
r186634 started verifying debug info, and r194986 disabled it by default
because it was too expensive to run the checks on every function (since
most of the graph was reachable from each function).

r206300 moved the checks to module-level to make it cheaper, but there
was already quite a bit of testcase bitrot (and the verifier would only
print `<badref>`) so I guess no one had time to turn it back on.

This does just that.  Upgrade scripts this past autumn and winter
probably fixed some of the bitrot, and this weekend I fixed the verifier
output (r232275, r232417, r232418) and thusly the remaining failing
testcases (r232290, r232415).

This is part of PR22777.

llvm-svn: 232505
2015-03-17 17:28:41 +00:00
Duncan P. N. Exon Smith 7401b1e780 Verifier: Don't call debug info verifier if the module is broken
If `Verifier` has already found a failure, don't call
`DebugInfoVerifier`.  The latter sometimes crashes in `DebugInfoFinder`
when the former would give a nice message.  The only two cases I found
it crashing are explicit verifier tests I've added:

  - test/Verifier/llvm.dbg.declare-expression.ll
  - test/Verifier/llvm.dbg.value-expression.ll

However, I assume frontends with bugs will create invalid IR as well.

IMO, the `DebugInfoVerifier` should never crash (instead, it should fail
to verify), but subtleties like that will be easier to work out once
it's enabled again.

This is part of PR22777.

llvm-svn: 232418
2015-03-16 21:23:56 +00:00
Duncan P. N. Exon Smith 9255a5535a Verifier: Simplify logic in processCallInst(), NFC
No need for local variables here.

llvm-svn: 232413
2015-03-16 21:05:33 +00:00
Duncan P. N. Exon Smith e9d379c038 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.

llvm-svn: 232412
2015-03-16 21:03:55 +00:00
Duncan P. N. Exon Smith 18e92078f2 Verifier: Remove unnecessary double-checks
Turns out `visitIntrinsicFunctionCall()` descends into all operands
already, so explicitly descending in `visitDbgIntrinsic()` (part of
r232296) isn't useful.

Updating a testcase that doesn't really need `-verify-debug-info` (since
r231082) as confirmation.

llvm-svn: 232408
2015-03-16 20:24:02 +00:00
Duncan P. N. Exon Smith f2929c9b03 Fix doxygen comments from r232268
llvm-svn: 232388
2015-03-16 17:49:03 +00:00
Duncan P. N. Exon Smith 25cf28fd7b DbgIntrinsicInst: Downcast to specialized MDNodes in accessors
Change accessors to downcast to `MDLocalVariable` and `MDExpression`,
now that we have -verify checks in place to confirm that it's safe.

llvm-svn: 232299
2015-03-15 01:23:20 +00:00
Duncan P. N. Exon Smith 166121ad0b Verifier: Check debug info intrinsic arguments
Verify that debug info intrinsic arguments are valid.  (These checks
will not recurse through the full debug info graph, so they don't need
to be cordoned of in `DebugInfoVerifier`.)

With those checks in place, changing the `DbgIntrinsicInst` accessors to
downcast to `MDLocalVariable` and `MDExpression` is natural (added isa
specializations in `Metadata.h` to support this).

Added tests to `test/Verifier` for the new -verify checks, and fixed the
debug info in all the in-tree tests.

If you have out-of-tree testcases that have started to fail to -verify,
hopefully the verify checks are helpful.  The most likely problem is
that the expression argument is `!{}` (instead of `!MDExpression()`).

llvm-svn: 232296
2015-03-15 01:21:30 +00:00
Duncan P. N. Exon Smith 959299e7d1 Verifier: Remove unnecessary null check
This is already assumed to be non-null above due to a dyn_cast<>.  Also
remove extraneous braces around statement.

llvm-svn: 232292
2015-03-15 00:50:57 +00:00
Duncan P. N. Exon Smith 6fb58c4f7b Verifier: Make the raw_ostream constructor argument required
This was passed inconsistently; seems clearer to make it required anyway.

llvm-svn: 232291
2015-03-15 00:46:57 +00:00
Duncan P. N. Exon Smith d6d70e753d IR: Make Metadata::print() reliable and useful
Replumb the `AsmWriter` so that `Metadata::print()` is generally useful.
(Similarly change `Metadata::printAsOperand()`.)

- `SlotTracker` now has a mode where all metadata will be correctly
  numbered when initializing a `Module`.  Normally, `Metadata` only
  referenced from within `Function`s gets numbered when the `Function`
  is incorporated.
- `Metadata::print()` and `Metadata::printAsOperand()` (and
  `Metadata::dump()`) now take an optional `Module` argument.  When
  provided, `SlotTracker` is initialized with the new mode, and the
  numbering will be complete and consistent for all calls to `print()`.
- `Value::print()` uses the new `SlotTracker` mode when printing
  intrinsics with `MDNode` operands, `MetadataAsValue` operands, or the
  bodies of functions.  Thus, metadata numbering will be consistent
  between calls to `Metadata::print()` and `Value::print()`.
- `Metadata::print()` (and `Metadata::dump()`) now print the full
  definition of `MDNode`s:

    !5 = !{!6, !"abc", !7}

  This matches behaviour for `Value::print()`, which includes the name
  of instructions.
- Updated call sites in `Verifier` to call `print()` instead of
  `printAsOperand()`.

All this, so that `Verifier` can print out useful failure messages that
involve `Metadata` for PR22777.

Note that `Metadata::printAsOperand()` previously took an optional
`bool` and `Module` operand.  The former was cargo-culted from
`Value::printAsOperand()` and wasn't doing anything useful.  The latter
didn't give consistent results (without the new `SlotTracker` mode).

llvm-svn: 232275
2015-03-14 20:19:36 +00:00
Duncan P. N. Exon Smith ec9d3f779a Recover the ability to 'b CheckFailed' after r231577
Given that the stated purpose of `CheckFailed()` is to provide a nice
spot for a breakpoint, it'd be nice not to have to use a regex to break
on it.  Recover the ability to simply use `b CheckFailed` by
specializing the message-only version, and by changing the variadic
version to call into the message-only version.

llvm-svn: 232268
2015-03-14 16:47:37 +00:00
Owen Anderson 08f46e1de6 Fix an infinite recursion in the verifier caused by calling isSized on a recursive type.
llvm-svn: 232143
2015-03-13 06:41:26 +00:00
Owen Anderson a3c68fdf82 Fix another verifier crash where a GC intrinsic would look at the internals of another intrinsic in order to verify itself.
This causes a crash if the referenced intrinsic was malformed.  In this case, we
would already have reported an error on the referenced intrinsic, but then
crashed on the second one when it tried to introspect the first without
error checking.

llvm-svn: 231910
2015-03-11 06:57:30 +00:00
Owen Anderson 3e7e67b5ed Fix an issue in the verifier where we could try to read information out of a malformed statepoint intrinsic.
In this situation we would always have already flagged an error on the statepoint intrinsic,
but then we carry on to parse other, related GC intrinsics, and could end up crashing during that
verification when they try to access data from the malformed statepoint.

llvm-svn: 231759
2015-03-10 05:58:21 +00:00
David Blaikie dc3f01e9cf Simplify expressions involving boolean constants with clang-tidy
Patch by Richard (legalize at xmission dot com).

Differential Revision: http://reviews.llvm.org/D8154

llvm-svn: 231617
2015-03-09 01:57:13 +00:00
Benjamin Kramer f027ad7883 Make the assertion macros in Verifier and Linter truly variadic.
NFC.

llvm-svn: 231577
2015-03-07 21:15:40 +00:00
Reid Kleckner 286b100750 Remove accidental errs() call in Verifier
llvm-svn: 231391
2015-03-05 19:05:25 +00:00
Reid Kleckner cfb9ce53c1 Replace llvm.frameallocate with llvm.frameescape
Turns out it's pretty straightforward and simplifies the implementation.

Reviewers: andrew.w.kaylor

Differential Revision: http://reviews.llvm.org/D8051

llvm-svn: 231386
2015-03-05 18:26:34 +00:00
Owen Anderson 63fbf10c32 Teach the verifier to enforce that the alignment argument of memory intrinsics must be a power of 2.
llvm-svn: 230941
2015-03-02 09:35:06 +00:00
David Majnemer ab457815f3 Verifier: Unused comdats might not have a corresponding GV
This fixes PR22646.

llvm-svn: 230051
2015-02-20 19:58:48 +00:00
Igor Laevsky 9570ff94f7 Implement invoke statepoint verification.
Differential Revision: http://reviews.llvm.org/D7366

llvm-svn: 229840
2015-02-19 11:28:47 +00:00
Benjamin Kramer 6cd780ff21 Prefer SmallVector::append/insert over push_back loops.
Same functionality, but hoists the vector growth out of the loop.

llvm-svn: 229500
2015-02-17 15:29:18 +00:00
David Majnemer 04b4ed329e Verifier: Diagnose module flags which have null ID operands
llvm-svn: 229361
2015-02-16 08:14:22 +00:00
Duncan P. N. Exon Smith 193a4fdafd IR: Add MDExpression::ExprOperand
Port `DIExpression::Operand` over to `MDExpression::ExprOperand`.  The
logic is needed directly in `MDExpression` to support printing in
assembly.

llvm-svn: 229002
2015-02-13 01:07:46 +00:00
David Majnemer d7677e7a8d Verifier: Check for null operands in !llvm.module.flags
llvm-svn: 228818
2015-02-11 09:13:06 +00:00
David Majnemer 9fd8cdc009 Verifier: Make sure !llvm.ident's operand isn't null
llvm-svn: 228815
2015-02-11 08:23:20 +00:00
Duncan P. N. Exon Smith 9e95f27eff Verifier: reuse getInlinedAt() result, NFC
llvm-svn: 228655
2015-02-10 02:25:18 +00:00
Duncan P. N. Exon Smith e4725beba7 Verifier: Check for valid tags in debug nodes
Check that specialized `DebugNode`s have valid `DW_TAG`s.

llvm-svn: 228649
2015-02-10 01:40:40 +00:00
Duncan P. N. Exon Smith 692bdb910d Verifier: Add simple checks for MDLocation
llvm-svn: 228647
2015-02-10 01:32:56 +00:00
Duncan P. N. Exon Smith b0a19ad08a Verifier: Create stubs for specialized metadata nodes
llvm-svn: 228645
2015-02-10 01:09:50 +00:00
Duncan P. N. Exon Smith ac3ed7afc9 Verifier: Const-qualify Metadata, NFC
llvm-svn: 228609
2015-02-09 21:30:05 +00:00
Elena Demikhovsky 23a485a4ed Masked Gather and Scatter Intrinsics.
Gather and Scatter are new introduced intrinsics, comming after recently implemented masked load and store.
This is the first patch for Gather and Scatter intrinsics. It includes only the syntax, parsing and verification.

Gather and Scatter intrinsics allow to perform multiple memory accesses (read/write) in one vector instruction.
The intrinsics are not target specific and will have the following syntax:
Gather:
declare <16 x i32> @llvm.masked.gather.v16i32(<16 x i32*> <vector of ptrs>, i32 <alignment>, <16 x i1> <mask>, <16 x i32> <passthru>)
declare <8 x float> @llvm.masked.gather.v8f32(<8 x float*><vector of ptrs>, i32 <alignment>, <8 x i1> <mask>, <8 x float><passthru>)

Scatter:
declare void @llvm.masked.scatter.v8i32(<8 x i32><vector value to be stored> , <8 x i32*><vector of ptrs> , i32 <alignment>, <8 x i1> <mask>)
declare void @llvm.masked.scatter.v16i32(<16 x i32> <vector value to be stored> , <16 x i32*> <vector of ptrs>, i32 <alignment>, <16 x i1><mask> )

Vector of ptrs - a set of source/destination addresses, to load/store the value. 
Mask - switches on/off vector lanes to prevent memory access for switched-off lanes
vector of ptrs, value and mask should have the same vector width.

These are code examples where gather / scatter should be used and will allow function vectorization
;void foo1(int * restrict A, int * restrict B, int * restrict C) {
; for (int i=0; i<SIZE; i++) {
; A[i] = B[C[i]];
; }
;}

;void foo3(int * restrict A, int * restrict B) {
; for (int i=0; i<SIZE; i++) {
; A[B[i]] = i+5;
; }
;}

Tests will come in the following patches, with CodeGen and Vectorizer.

http://reviews.llvm.org/D7433

llvm-svn: 228521
2015-02-08 08:27:19 +00:00
Philip Reames 0285c74261 Use ImmutableCallSite for statepoint verification.
Patch by: Igor Laevsky

"This change generalizes statepoint verification to use ImmutableCallSite instead of CallInst. This will allow to easily implement invoke statepoint verification (in a following change)."

Differential Revision: http://reviews.llvm.org/D7308

llvm-svn: 228064
2015-02-03 23:18:47 +00:00
Philip Reames 1ffa9377e1 Factor out statepoint verification into separate function. (NFC)
Patch by: Igor Laevsky

"Simple refactoring. This is done in preparation to support verification of invokable statepoints."

Differential Revision: http://reviews.llvm.org/D7276

llvm-svn: 227640
2015-01-30 23:28:05 +00:00
Ramkumar Ramachandra 75a4f35b26 Intrinsics: introduce llvm_any_ty aka ValueType Any
Specifically, gc.result benefits from this greatly. Instead of:

gc.result.int.*
gc.result.float.*
gc.result.ptr.*
...

We now have a gc.result.* that can specialize to literally any type.

Differential Revision: http://reviews.llvm.org/D7020

llvm-svn: 226857
2015-01-22 20:14:38 +00:00
Adrian Prantl 34bcbeed03 Make DIExpression::Verify() stricter by checking that the number of
elements and the ordering is sane and cleanup the accessors.

llvm-svn: 226627
2015-01-21 00:59:20 +00:00
Ramkumar Ramachandra be10ece5ed [GC] Verify-pass void vararg functions in gc.statepoint
With the appropriate Verifier changes, exactracting the result out of a
statepoint wrapping a vararg function crashes. However, a void vararg
function works fine: commit this first step.

Differential Revision: http://reviews.llvm.org/D7071

llvm-svn: 226599
2015-01-20 19:42:46 +00:00
Duncan P. N. Exon Smith 946fdcc50c IR: Remove MDNodeFwdDecl
Remove `MDNodeFwdDecl` (as promised in r226481).  Aside from API
changes, there's no real functionality change here.
`MDNode::getTemporary()` now forwards to `MDTuple::getTemporary()`,
which returns a tuple with `isTemporary()` equal to true.

The main point is that we can now add temporaries of other `MDNode`
subclasses, needed for PR22235 (I introduced `MDNodeFwdDecl` in the
first place because I didn't recognize this need, and thought they were
only needed to handle forward references).

A few things left out of (or highlighted by) this commit:

  - I've had to remove the (few) uses of `std::unique_ptr<>` to deal
    with temporaries, since the destructor is no longer public.
    `getTemporary()` should probably return the equivalent of
    `std::unique_ptr<T, MDNode::deleteTemporary>`.
  - `MDLocation::getTemporary()` doesn't exist yet (worse, it actually
    does exist, but does the wrong thing: `MDNode::getTemporary()` is
    inherited and returns an `MDTuple`).
  - `MDNode` now only has one subclass, `UniquableMDNode`, and the
    distinction between them is actually somewhat confusing.

I'll fix those up next.

llvm-svn: 226501
2015-01-19 20:36:39 +00:00
Ramkumar Ramachandra 40c3e03e27 Standardize {pred,succ,use,user}_empty()
The functions {pred,succ,use,user}_{begin,end} exist, but many users
have to check *_begin() with *_end() by hand to determine if the
BasicBlock or User is empty. Fix this with a standard *_empty(),
demonstrating a few usecases.

llvm-svn: 225760
2015-01-13 03:46:47 +00:00
Reid Kleckner 3542ace6ef Rename llvm.recoverframeallocation to llvm.framerecover
This name is less descriptive, but it sort of puts things in the
'llvm.frame...' namespace, relating it to frameallocate and
frameaddress. It also avoids using "allocate" and "allocation" together.

llvm-svn: 225752
2015-01-13 01:51:34 +00:00
Reid Kleckner e9b8931873 Add the llvm.frameallocate and llvm.recoverframeallocation intrinsics
These intrinsics allow multiple functions to share a single stack
allocation from one function's call frame. The function with the
allocation may only perform one allocation, and it must be in the entry
block.

Functions accessing the allocation call llvm.recoverframeallocation with
the function whose frame they are accessing and a frame pointer from an
active call frame of that function.

These intrinsics are very difficult to inline correctly, so the
intention is that they be introduced rarely, or at least very late
during EH preparation.

Reviewers: echristo, andrew.w.kaylor

Differential Revision: http://reviews.llvm.org/D6493

llvm-svn: 225746
2015-01-13 00:48:10 +00:00
Philip Reames 76ebd15437 [GC] improve testing around gc.relocate and fix a test
Patch by: Ramkumar Ramachandra <artagnon@gmail.com>

"This patch started out as an exploration of gc.relocate, and an attempt
to write a simple test in call-lowering. I then noticed that the
arguments of gc.relocate were not checked fully, so I went in and fixed
a few things. Finally, the most important outcome of this patch is that
my new error handling code caught a bug in a callsite in
stackmap-format."

Differential Revision: http://reviews.llvm.org/D6824

llvm-svn: 225412
2015-01-07 22:48:01 +00:00
Chandler Carruth d174ce4ad1 [PM] Switch the new pass manager to use a reference-based API for IR
units.

This was debated back and forth a bunch, but using references is now
clearly cleaner. Of all the code written using pointers thus far, in
only one place did it really make more sense to have a pointer. In most
cases, this just removes immediate dereferencing from the code. I think
it is much better to get errors on null IR units earlier, potentially
at compile time, than to delay it.

Most notably, the legacy pass manager uses references for its routines
and so as more and more code works with both, the use of pointers was
likely to become really annoying. I noticed this when I ported the
domtree analysis over and wrote the entire thing with references only to
have it fail to compile. =/ It seemed better to switch now than to
delay. We can, of course, revisit this is we learn that references are
really problematic in the API.

llvm-svn: 225145
2015-01-05 02:47:05 +00:00
Elena Demikhovsky fb81b93e17 Masked Load/Store - Changed the order of parameters in intrinsics.
No functional changes.
The documentation is coming.

llvm-svn: 224829
2014-12-25 07:49:20 +00:00
Rafael Espindola a4a94f1b55 Use CastInst::castIsValid to simplify the verifier.
Also delete a dead member variable.

llvm-svn: 224356
2014-12-16 19:29:29 +00:00
Duncan P. N. Exon Smith 5bf8fef580 IR: Split Metadata from Value
Split `Metadata` away from the `Value` class hierarchy, as part of
PR21532.  Assembly and bitcode changes are in the wings, but this is the
bulk of the change for the IR C++ API.

I have a follow-up patch prepared for `clang`.  If this breaks other
sub-projects, I apologize in advance :(.  Help me compile it on Darwin
I'll try to fix it.  FWIW, the errors should be easy to fix, so it may
be simpler to just fix it yourself.

This breaks the build for all metadata-related code that's out-of-tree.
Rest assured the transition is mechanical and the compiler should catch
almost all of the problems.

Here's a quick guide for updating your code:

  - `Metadata` is the root of a class hierarchy with three main classes:
    `MDNode`, `MDString`, and `ValueAsMetadata`.  It is distinct from
    the `Value` class hierarchy.  It is typeless -- i.e., instances do
    *not* have a `Type`.

  - `MDNode`'s operands are all `Metadata *` (instead of `Value *`).

  - `TrackingVH<MDNode>` and `WeakVH` referring to metadata can be
    replaced with `TrackingMDNodeRef` and `TrackingMDRef`, respectively.

    If you're referring solely to resolved `MDNode`s -- post graph
    construction -- just use `MDNode*`.

  - `MDNode` (and the rest of `Metadata`) have only limited support for
    `replaceAllUsesWith()`.

    As long as an `MDNode` is pointing at a forward declaration -- the
    result of `MDNode::getTemporary()` -- it maintains a side map of its
    uses and can RAUW itself.  Once the forward declarations are fully
    resolved RAUW support is dropped on the ground.  This means that
    uniquing collisions on changing operands cause nodes to become
    "distinct".  (This already happened fairly commonly, whenever an
    operand went to null.)

    If you're constructing complex (non self-reference) `MDNode` cycles,
    you need to call `MDNode::resolveCycles()` on each node (or on a
    top-level node that somehow references all of the nodes).  Also,
    don't do that.  Metadata cycles (and the RAUW machinery needed to
    construct them) are expensive.

  - An `MDNode` can only refer to a `Constant` through a bridge called
    `ConstantAsMetadata` (one of the subclasses of `ValueAsMetadata`).

    As a side effect, accessing an operand of an `MDNode` that is known
    to be, e.g., `ConstantInt`, takes three steps: first, cast from
    `Metadata` to `ConstantAsMetadata`; second, extract the `Constant`;
    third, cast down to `ConstantInt`.

    The eventual goal is to introduce `MDInt`/`MDFloat`/etc. and have
    metadata schema owners transition away from using `Constant`s when
    the type isn't important (and they don't care about referring to
    `GlobalValue`s).

    In the meantime, I've added transitional API to the `mdconst`
    namespace that matches semantics with the old code, in order to
    avoid adding the error-prone three-step equivalent to every call
    site.  If your old code was:

        MDNode *N = foo();
        bar(isa             <ConstantInt>(N->getOperand(0)));
        baz(cast            <ConstantInt>(N->getOperand(1)));
        bak(cast_or_null    <ConstantInt>(N->getOperand(2)));
        bat(dyn_cast        <ConstantInt>(N->getOperand(3)));
        bay(dyn_cast_or_null<ConstantInt>(N->getOperand(4)));

    you can trivially match its semantics with:

        MDNode *N = foo();
        bar(mdconst::hasa               <ConstantInt>(N->getOperand(0)));
        baz(mdconst::extract            <ConstantInt>(N->getOperand(1)));
        bak(mdconst::extract_or_null    <ConstantInt>(N->getOperand(2)));
        bat(mdconst::dyn_extract        <ConstantInt>(N->getOperand(3)));
        bay(mdconst::dyn_extract_or_null<ConstantInt>(N->getOperand(4)));

    and when you transition your metadata schema to `MDInt`:

        MDNode *N = foo();
        bar(isa             <MDInt>(N->getOperand(0)));
        baz(cast            <MDInt>(N->getOperand(1)));
        bak(cast_or_null    <MDInt>(N->getOperand(2)));
        bat(dyn_cast        <MDInt>(N->getOperand(3)));
        bay(dyn_cast_or_null<MDInt>(N->getOperand(4)));

  - A `CallInst` -- specifically, intrinsic instructions -- can refer to
    metadata through a bridge called `MetadataAsValue`.  This is a
    subclass of `Value` where `getType()->isMetadataTy()`.

    `MetadataAsValue` is the *only* class that can legally refer to a
    `LocalAsMetadata`, which is a bridged form of non-`Constant` values
    like `Argument` and `Instruction`.  It can also refer to any other
    `Metadata` subclass.

(I'll break all your testcases in a follow-up commit, when I propagate
this change to assembly.)

llvm-svn: 223802
2014-12-09 18:38:53 +00:00
Elena Demikhovsky f1de34b84d Masked Load / Store Intrinsics - the CodeGen part.
I'm recommiting the codegen part of the patch.
The vectorizer part will be send to review again.

Masked Vector Load and Store Intrinsics.
Introduced new target-independent intrinsics in order to support masked vector loads and stores. The loop vectorizer optimizes loops containing conditional memory accesses by generating these intrinsics for existing targets AVX2 and AVX-512. The vectorizer asks the target about availability of masked vector loads and stores.
Added SDNodes for masked operations and lowering patterns for X86 code generator.
Examples:
<16 x i32> @llvm.masked.load.v16i32(i8* %addr, <16 x i32> %passthru, i32 4 /* align */, <16 x i1> %mask)
declare void @llvm.masked.store.v8f64(i8* %addr, <8 x double> %value, i32 4, <8 x i1> %mask)

Scalarizer for other targets (not AVX2/AVX-512) will be done in a separate patch.

http://reviews.llvm.org/D6191

llvm-svn: 223348
2014-12-04 09:40:44 +00:00
Philip Reames a7eb3cb46e A few more checks for gc.statepoints in the Verifier
This is simply a grab bag of unrelated checks:
- A statepoint call can't be marked readonly or readnone
- We don't currently support inline asm or varadic target functions.  Both could be supported, but don't currently work.
- I forgot to check that the number of call arguments actually matched the wrapped callee in my previous change.  Included here.

llvm-svn: 223322
2014-12-04 00:01:48 +00:00
Philip Reames b23713aae9 Strength Verifier checks around the types involved in a statepoint
Add checks that the types in a gc.statepoint sequence match the wrapper callee and that relocating a pointer doesn't change it's type.

llvm-svn: 223275
2014-12-03 22:23:24 +00:00
Philip Reames 38303a329f Make the Verifier more strict about gc.statepoints
The recently added documentation for statepoints claimed that we checked the parameters of the various intrinsics for validity.  This patch adds the code to actually do so.  I also removed a couple of redundant checks for conditions which are checked elsewhere in the Verifier and simplified the logic using the helper functions from Statepoint.h.

llvm-svn: 223259
2014-12-03 19:53:15 +00:00
Philip Reames 337c4bd4ab [Statepoints 1/4] Statepoint infrastructure for garbage collection: IR Intrinsics
The statepoint intrinsics are intended to enable precise root tracking through the compiler as to support garbage collectors of all types. The addition of the statepoint intrinsics to LLVM should have no impact on the compilation of any program which does not contain them. There are no side tables created, no extra metadata, and no inhibited optimizations.

A statepoint works by transforming a call site (or safepoint poll site) into an explicit relocation operation. It is the frontend's responsibility (or eventually the safepoint insertion pass we've developed, but that's not part of this patch series) to ensure that any live pointer to a GC object is correctly added to the statepoint and explicitly relocated. The relocated value is just a normal SSA value (as seen by the optimizer), so merges of relocated and unrelocated values are just normal phis. The explicit relocation operation, the fact the statepoint is assumed to clobber all memory, and the optimizers standard semantics ensure that the relocations flow through IR optimizations correctly.

This is the first patch in a small series.  This patch contains only the IR parts; the documentation and backend support will be following separately.  The entire series can be seen as one combined whole in http://reviews.llvm.org/D5683.

Reviewed by: atrick, ributzka

llvm-svn: 223078
2014-12-01 21:18:12 +00:00
Duncan P. N. Exon Smith 9bc81fbe92 Revert "Masked Vector Load and Store Intrinsics."
This reverts commit r222632 (and follow-up r222636), which caused a host
of LNT failures on an internal bot.  I'll respond to the commit on the
list with a reproduction of one of the failures.

Conflicts:
	lib/Target/X86/X86TargetTransformInfo.cpp

llvm-svn: 222936
2014-11-28 21:29:14 +00:00
Elena Demikhovsky 9e5089a938 Masked Vector Load and Store Intrinsics.
Introduced new target-independent intrinsics in order to support masked vector loads and stores. The loop vectorizer optimizes loops containing conditional memory accesses by generating these intrinsics for existing targets AVX2 and AVX-512. The vectorizer asks the target about availability of masked vector loads and stores.
Added SDNodes for masked operations and lowering patterns for X86 code generator.
Examples:
<16 x i32> @llvm.masked.load.v16i32(i8* %addr, <16 x i32> %passthru, i32 4 /* align */, <16 x i1> %mask)
declare void @llvm.masked.store.v8f64(i8* %addr, <8 x double> %value, i32 4, <8 x i1> %mask)

Scalarizer for other targets (not AVX2/AVX-512) will be done in a separate patch.

http://reviews.llvm.org/D6191

llvm-svn: 222632
2014-11-23 08:07:43 +00:00
Zachary Turner 8325a5c6f8 Add curly braces to workaround an MSVC bug.
MSVC can't parse this pattern for range-based for loops.

llvm-svn: 222491
2014-11-21 01:19:09 +00:00
Adrian Prantl 940257f7e4 Verifier: Check that all instructions have their parent pointers set up
correctly. This helps with catching problems caused by IRBuilder abuse
such as the one fixed in CFE r222487.

llvm-svn: 222488
2014-11-21 00:39:43 +00:00
David Blaikie 70573dcd9f Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool>
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.

This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...

llvm-svn: 222334
2014-11-19 07:49:26 +00:00
Duncan P. N. Exon Smith de36e8040f Revert "IR: MDNode => Value"
Instead, we're going to separate metadata from the Value hierarchy.  See
PR21532.

This reverts commit r221375.
This reverts commit r221373.
This reverts commit r221359.
This reverts commit r221167.
This reverts commit r221027.
This reverts commit r221024.
This reverts commit r221023.
This reverts commit r220995.
This reverts commit r220994.

llvm-svn: 221711
2014-11-11 21:30:22 +00:00
Duncan P. N. Exon Smith c5754a65e6 IR: MDNode => Value: NamedMDNode::getOperator()
Change `NamedMDNode::getOperator()` from returning `MDNode *` to
returning `Value *`.  To reduce boilerplate at some call sites, add a
`getOperatorAsMDNode()` for named metadata that's expected to only
return `MDNode` -- for now, that's everything, but debug node named
metadata (such as llvm.dbg.cu and llvm.dbg.sp) will soon change.  This
is part of PR21433.

Note that there's a follow-up patch to clang for the API change.

llvm-svn: 221375
2014-11-05 18:16:03 +00:00
Rafael Espindola 246c4fb5d9 Remove redundant calls to isMaterializable.
This removes calls to isMaterializable in the following cases:

* It was redundant with a call to isDeclaration now that isDeclaration returns
  the correct answer for materializable functions.
* It was followed by a call to Materialize. Just call Materialize and check EC.

llvm-svn: 221050
2014-11-01 16:46:18 +00:00
Duncan P. N. Exon Smith 3872d0084c IR: MDNode => Value: Instruction::getMetadata()
Change `Instruction::getMetadata()` to return `Value` as part of
PR21433.

Update most callers to use `Instruction::getMDNode()`, which wraps the
result in a `cast_or_null<MDNode>`.

llvm-svn: 221024
2014-11-01 00:10:31 +00:00
Rafael Espindola d4bcefc7d9 Don't ever call materializeAllPermanently during LTO.
To do this, change the representation of lazy loaded functions.

The previous representation cannot differentiate between a function whose body
has been removed and one whose body hasn't been read from the .bc file. That
means that in order to drop a function, the entire body had to be read.

llvm-svn: 220580
2014-10-24 18:13:04 +00:00
Philip Reames 0ca58b33cf Extend the verifier to check usage of 'nonnull' metadata.
The recently added !nonnull metadata is only valid on loads of pointer type.  

llvm-svn: 220323
2014-10-21 20:56:29 +00:00
Philip Reames bf9676f7f0 Extend the verifier to validate range metadata on calls and invokes.
Range metadata applies to loads, call, and invokes.  We were validating that metadata applied to loads was correct according to the LangRef, but we were not validating metadata applied to calls or invokes.  This change extracts the checking functionality to a common location, reuses it for all valid locations, and adds a simple test to ensure a misused range on a call gets reported.

llvm-svn: 220246
2014-10-20 23:52:07 +00:00
Juergen Ributzka ad2363f9ee [Stackmaps] Enable invoking the patchpoint intrinsic.
Patch by Kevin Modzelewski
Reviewers: atrick, ributzka
Reviewed By: ributzka
Subscribers: llvm-commits, reames

Differential Revision: http://reviews.llvm.org/D5634

llvm-svn: 220055
2014-10-17 17:39:00 +00:00
Alexey Samsonov af023adb86 Be more careful in parsing Module::ModFlagBehavior value
to make sure we don't do invalid load of an enum. Share the
conversion code between llvm::Module implementation and the
verifier.

This bug was reported by UBSan.

llvm-svn: 217395
2014-09-08 19:16:28 +00:00
Reid Kleckner 329d4a2b29 Verifier: Don't reject varargs callee cleanup functions
We've rejected these kinds of functions since r28405 in 2006 because
it's impossible to lower the return of a callee cleanup varargs
function. However there are lots of legal ways to leave such a function
without returning, such as aborting. Today we can leave a function with
a musttail call to another function with the correct prototype, and
everything works out.

I'm removing the verifier check declaring that a normal return from such
a function is UB.

Reviewed By: nlewycky

Differential Revision: http://reviews.llvm.org/D5059

llvm-svn: 216779
2014-08-29 21:25:28 +00:00
Craig Topper 71b7b68b74 Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.
llvm-svn: 216158
2014-08-21 05:55:13 +00:00
Craig Topper 6230691c91 Revert "Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size."
Getting a weird buildbot failure that I need to investigate.

llvm-svn: 215870
2014-08-18 00:24:38 +00:00
Craig Topper 5229cfd163 Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.
llvm-svn: 215868
2014-08-17 23:47:00 +00:00
Duncan P. N. Exon Smith 6c99015fe2 Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges."
This reverts commit r213474 (and r213475), which causes a miscompile on
a stage2 LTO build.  I'll reply on the list in a moment.

llvm-svn: 213562
2014-07-21 17:06:51 +00:00
Manuel Jacob d11beffef4 [C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges.
Summary: This patch introduces two new iterator ranges and updates existing code to use it.  No functional change intended.

Test Plan: All tests (make check-all) still pass.

Reviewers: dblaikie

Reviewed By: dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4481

llvm-svn: 213474
2014-07-20 09:10:11 +00:00
Reid Kleckner 15fe7a530d Document the maximum LLVM IR alignment, which is 1 << 29 or 0.5 GiB
Add verifier checks.  We already check these in the assembly parser, but
a frontend producing IR in memory wouldn't hit those checks.

llvm-svn: 213027
2014-07-15 01:16:09 +00:00
David Majnemer ebc741168b IR: Allow comdats to be applied to globals with internal linkage
Our verifier check for checking if a global has local linkage was too
strict.  Forbid private linkage but permit local linkage.

Object file formats permit this and forbidding it prevents elimination
of unused, internal, vftables under the MSVC ABI.

llvm-svn: 212900
2014-07-13 04:56:11 +00:00
David Majnemer 329b5602d7 Verifier: Update assert message to reflect LangRef
No functionality change, just correcting the assertion message.

llvm-svn: 211977
2014-06-28 06:24:49 +00:00
David Majnemer dad0a645a7 IR: Add COMDATs to the IR
This new IR facility allows us to represent the object-file semantic of
a COMDAT group.

COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.

This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.

Differential Revision: http://reviews.llvm.org/D4178

llvm-svn: 211920
2014-06-27 18:19:56 +00:00
Jingyue Wu 37fcb5919d [ValueTracking] Extend range metadata to call/invoke
Summary:
With this patch, range metadata can be added to call/invoke including
IntrinsicInst. Previously, it could only be added to load.

Rename computeKnownBitsLoad to computeKnownBitsFromRangeMetadata because
range metadata is not only used by load.

Update the language reference to reflect this change.

Test Plan:
Add several tests in range-2.ll to confirm the verifier is happy with
having range metadata on call/invoke.

Add two tests in AddOverFlow.ll to confirm annotating range metadata to
call/invoke can benefit InstCombine.

Reviewers: meheff, nlewycky, reames, hfinkel, eliben

Reviewed By: eliben

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4187

llvm-svn: 211281
2014-06-19 16:50:16 +00:00
Bob Wilson 2f7cc01895 Fix verifier for GlobalAliases to avoid recursing into global initializers.
The verifier follows GlobalAlias operands so that it can detect cycles of
alias definitions. It was doing this in a way that caused it to also recurse
through initializers for the GlobalValue aliasees, and it would fail when
an initializer refers to a global that is a declaration and not a definition.
This patch causes it to stop recursing when it hits a global definition.
<rdar://problem/17277451>

llvm-svn: 210734
2014-06-12 01:46:54 +00:00
Rafael Espindola 42a4c9f9e0 Allow aliases to be unnamed_addr.
Alias with unnamed_addr were in a strange state. It is stored in GlobalValue,
the language reference talks about "unnamed_addr aliases" but the verifier
was rejecting them.

It seems natural to allow unnamed_addr in aliases:

* It is a property of how it is accessed, not of the data itself.
* It is perfectly possible to write code that depends on the address
of an alias.

This patch then makes unname_addr legal for aliases. One side effect is that
the syntax changes for a corner case: In globals, unnamed_addr is now printed
before the address space.

llvm-svn: 210302
2014-06-06 01:20:28 +00:00
Tom Roeder 44cb65fff1 Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.

This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.

llvm-svn: 210280
2014-06-05 19:29:43 +00:00
Rafael Espindola 4dc5dfc56b Clauses in a landingpad are always Constant. Use a stricter type.
llvm-svn: 210203
2014-06-04 18:51:31 +00:00
Rafael Espindola 64c1e18033 Allow alias to point to an arbitrary ConstantExpr.
This  patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.

This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like

@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
                                 i32 ptrtoint (i32* @bar to i32)) to i32*)

An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).

Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.

llvm-svn: 210062
2014-06-03 02:41:57 +00:00
Rafael Espindola 19913ee160 Use existing helper function.
No functionality change.

llvm-svn: 209639
2014-05-26 19:57:55 +00:00
Reid Kleckner fceb76f5f9 Add comdat key field to llvm.global_ctors and llvm.global_dtors
This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized.  This is necessary for MSVC
ABI compatibility.  Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.

Reviewers: nlewycky

Differential Revision: http://reviews.llvm.org/D3499

llvm-svn: 209015
2014-05-16 20:39:27 +00:00
Rafael Espindola 6b238633b7 Fix most of PR10367.
This patch changes the design of GlobalAlias so that it doesn't take a
ConstantExpr anymore. It now points directly to a GlobalObject, but its type is
independent of the aliasee type.

To avoid changing all alias related tests in this patches, I kept the common
syntax

@foo = alias i32* @bar

to mean the same as now. The cases that used to use cast now use the more
general syntax

@foo = alias i16, i32* @bar.

Note that GlobalAlias now behaves a bit more like GlobalVariable. We
know that its type is always a pointer, so we omit the '*'.

For the bitcode, a nice surprise is that we were writing both identical types
already, so the format change is minimal. Auto upgrade is handled by looking
through the casts and no new fields are needed for now. New bitcode will
simply have different types for Alias and Aliasee.

One last interesting point in the patch is that replaceAllUsesWith becomes
smart enough to avoid putting a ConstantExpr in the aliasee. This seems better
than checking and updating every caller.

A followup patch will delete getAliasedGlobal now that it is redundant. Another
patch will add support for an explicit offset.

llvm-svn: 209007
2014-05-16 19:35:39 +00:00