Summary:
Instead of constantly keeping track of the nonnull status with the
dereferenceable information we can simply query the nonnull attribute
whenever we need the information (debug + manifest).
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66113
llvm-svn: 368924
Summary:
As one of the first attributes, and one of the complex ones,
AAReturnedValues was not using liveness but we filtered the result after
the fact. This change adds liveness usage during the creation. The
algorithm is also improved and shorter.
The new algorithm will collect returned values over time using the
generic facilities that work with liveness already, e.g.,
genericValueTraversal which does not look at dead PHI node predecessors.
A test to show how this leads to better results is included.
Note: Unresolved calls and resolved calls are now tracked explicitly.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66120
llvm-svn: 368922
Summary:
If the associated context instruction is assumed dead we do not need to
update or manifest the state.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66116
llvm-svn: 368921
Summary:
The next attempt to clean up the Attributor interface before we grow it
further.
Before, we used a combination of two values (associated + anchor) and an
argument number (or -1) to determine a location. This was very fragile.
The new system uses exclusively IR positions and we restrict the
generation of IR positions to special constructor methods that verify
internal constraints we have. This will catch misuse early.
The auto-conversion, e.g., in getAAFor, is now performed through the
SubsumingPositionIterator. This iterator takes an IR position and allows
to visit all IR positions that "subsume" the given one, e.g., function
attributes "subsume" argument attributes of that function. For a
detailed breakdown see the class comment of SubsumingPositionIterator.
This patch also introduces the IRPosition::getAttrs() to extract IR
attributes at a certain position. The method knows how to look up in
different positions that are equivalent, e.g., the argument position for
call site arguments. We also introduce three new positions kinds such
that we have all IR positions where attributes can be placed and one for
"floating" values.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65977
llvm-svn: 368919
Summary:
The ever growing switch required Attribute::AttrKind values but they
might not be available for all abstract attributes we deduce. With the
new method we track statistics at the abstract attribute level. The
provided macros simplify the usage and make the messages uniform.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65732
llvm-svn: 368227
Summary:
The wrapper reduces boilerplate code and also provide a nice way to
determine the state type used by an abstract attributes statically via
AAType::StateType.
This was already discussed as part of the review of D65711.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65786
llvm-svn: 368224
If we know everything is live there is no need to query for liveness.
Indicating a pessimistic fixpoint will cause the state to be "invalid"
which will cause the Attributor to not return the AAIsDead on request,
which will prevent us from querying isAssumedDead().
llvm-svn: 368223
Summary:
So far, whenever one wants to look at returned values, one had to deal
with the AAReturnedValues and potentially with the AAIsDead attribute.
In the same spirit as other checkForAllXXX methods, we add this
functionality now to the Attributor. By adopting the use sites we got
better results when return instructions were dead.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65733
llvm-svn: 368222
Commit r368064 was necessary after r367953 (D65712) broke the module
build. That happened, apparently, because the template class IRAttribute
defined in the header had a virtual method defined in the corresponding
source file (IRAttribute::manifest). To unbreak the situation this patch
introduces a helper function IRAttributeManifest::manifestAttrs which
is used to implement IRAttribute::manifest in the header. The deifnition
of the helper function is still in the source file.
Patch by jdoerfert (Johannes Doerfert)
Differential Revision: https://reviews.llvm.org/D65821
llvm-svn: 368076
Summary:
Similar to `Attributor::checkForAllCallSites`, we now provide such
functionality for instructions of a certain opcode through
`Attributor::checkForAllInstructions` and the convenient wrapper
`Attributor::checkForAllCallLikeInstructions`. This cleans up code,
avoids duplication, and simplifies the usage of liveness information.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65731
llvm-svn: 367961
Summary:
Certain properties, e.g., an AttrKind, are not shared among all abstract
attributes. This patch extracts the functionality into a helper struct.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65712
llvm-svn: 367953
To remove boilerplate, mostly passing through values to the
AbstractAttriubute base class, we extract the state into an IRPosition
helper. There is no function change intended but the IRPosition struct
will provide more functionality down the line.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65711
llvm-svn: 367952
Summary:
The new scheme is similar to the pass manager and dyn_cast scheme where
we identify classes by the address of a static member. This is better
than the old scheme in which we had to "invent" new Attributor enums if
there was no corresponding one.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65710
llvm-svn: 367951
Summary:
Instead of storing the reference to the InformationCache we now pass it
whenever it might be needed.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65709
llvm-svn: 367950
A function is "no-return" if we never reach a return instruction, either
because there are none or the ones that exist are dead.
Test have been adjusted:
- either noreturn was added, or
- noreturn was avoided by modifying the code.
The new noreturn_{sync,async} test make sure we do handle invoke
instructions with a noreturn (and potentially nowunwind) callee
correctly, even in the presence of potential asynchronous exceptions.
llvm-svn: 367948
When we remove instructions cached references could still be live. This
patch avoids removing invoke instructions that are replaced by calls and
instead keeps them around but in a dead block.
llvm-svn: 367933
Similar to other places where we transform invokes to calls we need to
be careful if the handler (=personality) can catch asynchronous
exceptions as they are not modeled as part of nounwind.
This is tested with D59978.
llvm-svn: 367931
Summary:
This contains various fixes:
- Explicitly determine and return the next noreturn instruction.
- If an invoke calls a noreturn function which is not nounwind we
keep the unwind destination live. This also means we require an
invoke. Though we can still add the unreachable to the normal
destination block.
- Check if the return instructions are dead after we look for calls
to avoid triggering an optimistic fixpoint in the presence of
assumed liveness information.
- Make the interface work with "const" pointers.
- Some simplifications
While additional tests are included, full coverage is achieved only with
D59978.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65701
llvm-svn: 367791
When a fixpoint is indicated the change status is known due to the
fixpoint kind. This simplifies a common code pattern by making the
connection explicit.
llvm-svn: 367790
Summary:
If the DerefBytesState (and thereby the DerefState) is invalid, we
reached a fixpoint for the whole DerefState as we will not
manifest/provide information then.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65586
llvm-svn: 367789
Modifying other AbstractAttributes to use Liveness AA and skip dead instructions.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D65243
llvm-svn: 367725
User of AAReturnedValues need to know if HasOverdefinedReturnedCalls
changed from false to true as it will impact the result of the return
value traversal (calls are not ignored anymore).
This will be tested with the tests in D59978.
llvm-svn: 367581
Summary:
Deduce dereferenceable attribute in Attributor.
These will be added in a later patch.
* dereferenceable(_or_null)_globally (D61652)
* Deduction based on load instruction (similar to D64258)
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64876
llvm-svn: 366788
[Attributor] Liveness analysis.
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D64162
llvm-svn: 366769
[Attributor] Liveness analysis.
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D64162
llvm-svn: 366753
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D64162
llvm-svn: 366736
Porting function return value attribute noalias to attributor.
This will be followed with a patch for callsite and function argumets.
Reviewers: jdoerfert
Subscribers: lebedev.ri, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D63067
llvm-svn: 366728
Summary:
Deduce the "willreturn" attribute for functions.
For now, intrinsics are not willreturn. More annotation will be done in another patch.
Reviewers: jdoerfert
Subscribers: jvesely, nhaehnle, nicholas, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63046
llvm-svn: 366335
Attributor::getAAFor will now only return AbstractAttributes with a
valid AbstractState. This simplifies call sites as they only need to
check if the returned pointer is non-null. It also reduces the potential
for accidental misuse.
llvm-svn: 365983
Some function in the Attributor framework are unnecessarily
marked virtual. This patch removes virtual keyword
Reviewers: jdoerfert
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D64637
llvm-svn: 365925
Introduce and deduce "nosync" function attribute to indicate that a function
does not synchronize with another thread in a way that other thread might free memory.
Reviewers: jdoerfert, jfb, nhaehnle, arsenm
Subscribers: wdng, hfinkel, nhaenhle, mehdi_amini, steven_wu,
dexonsmith, arsenm, uenoku, hiraditya, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D62766
llvm-svn: 365830
Deduce the "returned" argument attribute by collecting all potentially
returned values.
Not only the unique return value, if any, can be used by subsequent
attributes but also the set of all potentially returned values as well
as the mapping from returned values to return instructions that they
originate from (see AAReturnedValues::checkForallReturnedValues).
Change in statistics (-stats) for LLVM-TS + Spec2006, totaling ~19% more "returned" arguments.
ADDED: attributor NumAttributesManifested n/a -> 637
ADDED: attributor NumAttributesValidFixpoint n/a -> 25545
ADDED: attributor NumFnArgumentReturned n/a -> 637
ADDED: attributor NumFnKnownReturns n/a -> 25545
ADDED: attributor NumFnUniqueReturned n/a -> 14118
CHANGED: deadargelim NumRetValsEliminated 470 -> 449 ( -4.468%)
REMOVED: functionattrs NumReturned 535 -> n/a
CHANGED: indvars NumElimIdentity 138 -> 164 ( +18.841%)
Reviewers: homerdin, hfinkel, fedor.sergeev, sanjoy, spatel, nlopes, nicholas, reames, efriedma, chandlerc
Subscribers: hiraditya, bollu, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D59919
llvm-svn: 365407
@jdoerfert Looks like these are placeholders for incoming abstract attributes patches so I've just commented the code out, even though this is usually frowned upon.
llvm-svn: 362592
NOTE: Note that no attributes are derived yet. This patch will not go in
alone but only with others that derive attributes. The framework is
split for review purposes.
This commit introduces the Attributor pass infrastructure and fixpoint
iteration framework. Further patches will introduce abstract attributes
into this framework.
In a nutshell, the Attributor will update instances of abstract
arguments until a fixpoint, or a "timeout", is reached. Communication
between the Attributor and the abstract attributes that are derived is
restricted to the AbstractState and AbstractAttribute interfaces.
Please see the file comment in Attributor.h for detailed information
including design decisions and typical use case. Also consider the class
documentation for Attributor, AbstractState, and AbstractAttribute.
Reviewers: chandlerc, homerdin, hfinkel, fedor.sergeev, sanjoy, spatel, nlopes, nicholas, reames
Subscribers: mehdi_amini, mgorny, hiraditya, bollu, steven_wu, dexonsmith, dang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59918
llvm-svn: 362578
Johannes Doerfert