Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.
The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).
This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.
As a follow-up I'll add:
bool operator<(AtomicOrdering, AtomicOrdering) = delete;
bool operator>(AtomicOrdering, AtomicOrdering) = delete;
bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.
Reviewers: jyknight, reames
Subscribers: jyknight, llvm-commits
Differential Revision: http://reviews.llvm.org/D18775
llvm-svn: 265602
A ``swifterror`` attribute can be applied to a function parameter or an
AllocaInst.
This commit does not include any target-specific change. The target-specific
optimization will come as a follow-up patch.
Differential Revision: http://reviews.llvm.org/D18092
llvm-svn: 265189
Summary:
Fixed pointers to go on the right hand side following coding guidelines. NFC.
Patch by Mandeep Singh Grang.
Reviewers: majnemer, arsenm, sanjoy
Differential Revision: http://reviews.llvm.org/D16866
llvm-svn: 259703
Summary:
The overloads of CallInst::Create and InvokeInst::Create that are used to
adjust operand bundles purport to create a new instruction "identical in
every way except [for] the operand bundles", so copy the DebugLoc along
with everything else.
Reviewers: sanjoy, majnemer
Subscribers: majnemer, dblaikie, llvm-commits
Differential Revision: http://reviews.llvm.org/D16157
llvm-svn: 257745
Summary:
At least for CoreCLR, a catchpad which immediately executes an
`unreachable` instruction indicates that the exception can never have a
matching type, and so such catchpads can be removed, and so can their
catchswitches if the catchswitch becomes empty.
Reviewers: rnk, andrew.w.kaylor, majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D15846
llvm-svn: 256809
It turns out that terminatepad gives little benefit over a cleanuppad
which calls the termination function. This is not sufficient to
implement fully generic filters but MSVC doesn't support them which
makes terminatepad a little over-designed.
Depends on D15478.
Differential Revision: http://reviews.llvm.org/D15479
llvm-svn: 255522
While we have successfully implemented a funclet-oriented EH scheme on
top of LLVM IR, our scheme has some notable deficiencies:
- catchendpad and cleanupendpad are necessary in the current design
but they are difficult to explain to others, even to seasoned LLVM
experts.
- catchendpad and cleanupendpad are optimization barriers. They cannot
be split and force all potentially throwing call-sites to be invokes.
This has a noticable effect on the quality of our code generation.
- catchpad, while similar in some aspects to invoke, is fairly awkward.
It is unsplittable, starts a funclet, and has control flow to other
funclets.
- The nesting relationship between funclets is currently a property of
control flow edges. Because of this, we are forced to carefully
analyze the flow graph to see if there might potentially exist illegal
nesting among funclets. While we have logic to clone funclets when
they are illegally nested, it would be nicer if we had a
representation which forbade them upfront.
Let's clean this up a bit by doing the following:
- Instead, make catchpad more like cleanuppad and landingpad: no control
flow, just a bunch of simple operands; catchpad would be splittable.
- Introduce catchswitch, a control flow instruction designed to model
the constraints of funclet oriented EH.
- Make funclet scoping explicit by having funclet instructions consume
the token produced by the funclet which contains them.
- Remove catchendpad and cleanupendpad. Their presence can be inferred
implicitly using coloring information.
N.B. The state numbering code for the CLR has been updated but the
veracity of it's output cannot be spoken for. An expert should take a
look to make sure the results are reasonable.
Reviewers: rnk, JosephTremoulet, andrew.w.kaylor
Differential Revision: http://reviews.llvm.org/D15139
llvm-svn: 255422
This change is discussed in D15392 and should allow us to effectively
revert:
http://llvm.org/viewvc/llvm-project?view=revision&revision=255261
if we canonicalize bitcasts ahead of extracts.
It should be safe to convert any pair of bitcasts into a single bitcast,
however, it was mentioned here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20110829/127089.html
that we're not allowed to bitcast from an x86_mmx to some other types, but I'm
not seeing any failures from that, and we have regression tests in CodeGen/X86
that appear to cover all of those cases.
Some day we'll get to remove that MMX wart from LLVM IR completely?
Differential Revision: http://reviews.llvm.org/D15468
llvm-svn: 255399
- This simplifies the CallSite class, arg_begin / arg_end are now
simple wrapper getters.
- In several places, we were creating CallSite instances solely to call
arg_begin and arg_end. With this change, that's no longer required.
llvm-svn: 255226
Test case attached (test case also checks that we don't drop the calling
convention, but that functionality was correct before this patch).
llvm-svn: 255088
Currently `OperandBundleUse::operandsHaveAttr` computes its result
without being given a specific operand. This is problematic because it
forces us to say that, e.g., even non-pointer operands in `"deopt"`
operand bundles are `readonly`, which doesn't make sense.
This commit changes `operandsHaveAttr` to work in the context of a
specific operand, so that we can give the operand attributes that make
sense for the operands's `llvm::Type`.
llvm-svn: 254764
Summary:
This change teaches LLVM's inliner to track and suitably adjust
deoptimization state (tracked via deoptimization operand bundles) as it
inlines through call sites. The operation is described in more detail
in the LangRef changes.
Reviewers: reames, majnemer, chandlerc, dexonsmith
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14552
llvm-svn: 253438
This was an omission in the patch that landed initial support for
operand bundles. So far we haven't hit this, but we will once the
inliner is able to inline calls to functions that contain calls with
operand bundles.
llvm-svn: 252645
Summary:
Data operands of a call or invoke consist of the call arguments, and
the bundle operands associated with the `call` (or `invoke`)
instruction. The motivation for this change is that we'd like to be
able to query "argument attributes" like `readonly` and `nocapture`
for bundle operands naturally.
This change also provides a conservative "implementation" for these
attributes for any bundle operand, and an extension point for future
work.
Reviewers: chandlerc, majnemer, reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14305
llvm-svn: 252077
Summary:
This is intended to make a later change simpler.
Note: adding this bounds checking required fixing `X86FastISel`. As
far I can tell I've preserved original behavior but a careful review
will be appreciated.
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14304
llvm-svn: 252073
Summary:
An unsigned comparision is equivalent to is corresponding signed version
if both the operands being compared are positive. Teach SCEV to use
this fact when profitable.
Reviewers: atrick, hfinkel, reames, nlewycky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13687
llvm-svn: 251051
Summary:
This makes attribute accessors on `CallInst` and `InvokeInst` do the
(conservatively) right thing. This essentially involves, in some
cases, *not* falling back querying the attributes on the called
`llvm::Function` when operand bundles are present.
Attributes locally present on the `CallInst` or `InvokeInst` will still
override operand bundle semantics. The LangRef has been amended to
reflect this. Note: this change does not do anything prevent
`-function-attrs` from inferring `CallSite` local attributes after
inspecting the called function -- that will be done as a separate
change.
I've used `-adce` and `-early-cse` to test these changes. There is
nothing special about these passes (and they did not require any
changes) except that they seemed be the easiest way to write the tests.
This change does not add deal with `argmemonly`. That's a later change
because alias analysis requires a related fix before `argmemonly` can be
tested.
Reviewers: reames, chandlerc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13961
llvm-svn: 250973
Summary:
This change teaches `CallInst`s and `InvokeInst`s to maintain a set of
operand bundles as part of its operands. `CallInst`s and `InvokeInst`s
with operand bundles co-allocate some space before their `Use` array to
hold meta information about which of its operands are part of an operand
bundle.
The strings corresponding to the bundle tags are interned into
`LLVMContextImpl::BundleTagCache`
This change does not include any parsing / bitcode support. That's the
next change.
Depends on D12455.
Reviewers: reames, chandlerc, majnemer, dexonsmith, kmod, JosephTremoulet, rnk, bogner
Subscribers: MatzeB, sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D12456
llvm-svn: 248527
Summary:
Add a `cleanupendpad` instruction, used to mark exceptional exits out of
cleanups (for languages/targets that can abort a cleanup with another
exception). The `cleanupendpad` instruction is similar to the `catchendpad`
instruction in that it is an EH pad which is the target of unwind edges in
the handler and which itself has an unwind edge to the next EH action.
The `cleanupendpad` instruction, similar to `cleanupret` has a `cleanuppad`
argument indicating which cleanup it exits. The unwind successors of a
`cleanuppad`'s `cleanupendpad`s must agree with each other and with its
`cleanupret`s.
Update WinEHPrepare (and docs/tests) to accomodate `cleanupendpad`.
Reviewers: rnk, andrew.w.kaylor, majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12433
llvm-svn: 246751
Summary:
WinEHPrepare is going to require that cleanuppad and catchpad produce values
of token type which are consumed by any cleanupret or catchret exiting the
pad. This change updates the signatures of those operators to require/enforce
that the type produced by the pads is token type and that the rets have an
appropriate argument.
The catchpad argument of a `CatchReturnInst` must be a `CatchPadInst` (and
similarly for `CleanupReturnInst`/`CleanupPadInst`). To accommodate that
restriction, this change adds a notion of an operator constraint to both
LLParser and BitcodeReader, allowing appropriate sentinels to be constructed
for forward references and appropriate error messages to be emitted for
illegal inputs.
Also add a verifier rule (noted in LangRef) that a catchpad with a catchpad
predecessor must have no other predecessors; this ensures that WinEHPrepare
will see the expected linear relationship between sibling catches on the
same try.
Lastly, remove some superfluous/vestigial casts from instruction operand
setters operating on BasicBlocks.
Reviewers: rnk, majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12108
llvm-svn: 245797
Some personality routines require funclet exit points to be clearly
marked, this is done by producing a token at the funclet pad and
consuming it at the corresponding ret instruction. CleanupReturnInst
already had a spot for this operand but CatchReturnInst did not.
Other personality routines don't need to use this which is why it has
been made optional.
llvm-svn: 245149
This introduces the basic functionality to support "token types".
The motivation stems from the need to perform operations on a Value
whose provenance cannot be obscured.
There are several applications for such a type but my immediate
motivation stems from WinEH. Our personality routine enforces a
single-entry - single-exit regime for cleanups. After several rounds of
optimizations, we may be left with a terminator whose "cleanup-entry
block" is not entirely clear because control flow has merged two
cleanups together. We have experimented with using labels as operands
inside of instructions which are not terminators to indicate where we
came from but found that LLVM does not expect such exotic uses of
BasicBlocks.
Instead, we can use this new type to clearly associate the "entry point"
and "exit point" of our cleanup. This is done by having the cleanuppad
yield a Token and consuming it at the cleanupret.
The token type makes it impossible to obscure or otherwise hide the
Value, making it trivial to track the relationship between the two
points.
What is the burden to the optimizer? Well, it turns out we have already
paid down this cost by accepting that there are certain calls that we
are not permitted to duplicate, optimizations have to watch out for
such instructions anyway. There are additional places in the optimizer
that we will probably have to update but early examination has given me
the impression that this will not be heroic.
Differential Revision: http://reviews.llvm.org/D11861
llvm-svn: 245029
This change was done as an audit and is by inspection. The new EH
system is still very much a work in progress. NFC for the landingpad
case.
llvm-svn: 243965
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support. Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.
Differential Revision: http://reviews.llvm.org/D11097
llvm-svn: 243766
Summary:
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support. Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.
Reviewers: rnk, JosephTremoulet, reames, nlewycky, rjmccall
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11041
llvm-svn: 241888
The personality routine currently lives in the LandingPadInst.
This isn't desirable because:
- All LandingPadInsts in the same function must have the same
personality routine. This means that each LandingPadInst beyond the
first has an operand which produces no additional information.
- There is ongoing work to introduce EH IR constructs other than
LandingPadInst. Moving the personality routine off of any one
particular Instruction and onto the parent function seems a lot better
than have N different places a personality function can sneak onto an
exceptional function.
Differential Revision: http://reviews.llvm.org/D10429
llvm-svn: 239940
This is to try make it very clear that subclasses shouldn't be changing
the value directly. Now that OperandList for normal instructions is computed
using the NumOperands, its critical that the NumOperands is accurate or we
could compute the wrong offset to the first operand.
I looked over all places which update NumOperands and they are all safe.
Hung off use User's don't use NumOperands to compute the OperandList so they
are safe to continue to manipulate it. The only other User which changed it
was GlobalVariable which has an optional init list but always allocated space
for a single Use. It was correctly setting NumOperands to 1 before setting an
initializer, and setting it to 0 after clearing the init list, so the order was safe.
Added some comments to that code to make sure that this isn't changed in future
without being aware of this constraint.
Reviewed by Duncan Exon Smith.
llvm-svn: 239621
We don't want anyone to access OperandList directly as its going to be removed
and computed instead. This uses getter's and setter's instead in which we
can later change the underlying implementation of OperandList.
Reviewed by Duncan Exon Smith.
llvm-svn: 239620
PhiNode, SwitchInst, LandingPad and IndirectBr all had virtually identical
logic for growing the hung off uses.
Move it to User so that they can all call a single shared implementation.
Their destructors were all empty after this change and were deleted. They all
have virtual clone_impl methods which can be used as vtable anchors.
Reviewed by Duncan Exon Smith.
llvm-svn: 239492
Now that the subclasses which care about hung off uses let ~User clean it up,
there's no need for a separate method. Just inline it to ~User and delete it.
Reviewed by Duncan Exon Smith.
llvm-svn: 239491
PhiNode's need to allocate space for an array of Use[N] and then BasicBlock*[N].
They had their own allocHungOffUses to handle all of this. This moves the logic
in to User::allocHungOffUses and PhiNode passes in a bool to say to allocate
the BB* space too.
Reviewed by Duncan Exon Smith.
llvm-svn: 239489
Alternatively, this type could be derived on-demand whenever
getResultElementType is called - if someone thinks that's the better
choice (simple time/space tradeoff), I'm happy to give it a go.
llvm-svn: 238716
JF Bastien