Transform interfaces are implemented, direction or via extensions, in
libraries belonging to multiple other dialects. Those dialects don't
need to depend on the non-interface part of the transform dialect, which
includes the growing number of ops and transitive dependency footprint.
Split out the interfaces into a separate library. This in turn requires
flipping the dependency from the interface on the dialect that has crept
in because both co-existed in one library. The interface shouldn't
depend on the transform dialect either.
As a consequence of splitting, the capability of the interpreter to
automatically walk the payload IR to identify payload ops of a certain
kind based on the type used for the entry point symbol argument is
disabled. This is a good move by itself as it simplifies the interpreter
logic. This functionality can be trivially replaced by a
`transform.structured.match` operation.
Adds `transform.func.cast_and_call` that takes a set of inputs and
outputs and replaces the uses of those outputs with a call to a function
at a specified insertion point.
The idea with this operation is to allow users to author independent IR
outside of a to-be-compiled module, and then match and replace a slice
of the program with a call to the external function.
Additionally adds a mechanism for populating a type converter with a set
of conversion materialization functions that allow insertion of
casts on the inputs/outputs to and from the types of the function
signature.
Introduce a new extension for simple print-debugging of the transform
dialect scripts. The initial version of this extension consists of two
ops that are printing the payload objects associated with transform
dialect values. Similar ops were already available in the test extenion
and several downstream projects, and were extensively used for testing.
Add a new transform operation that creates a new parameter containing the number of payload objects (operations, values or attributes) associated with the argument. This is useful in matching and for debugging purposes. This replaces three ad-hoc operations previously provided by the test extension.
This transform op applies a dialect conversion to the targeted ops. Its design is similar to `apply_patterns`.
Patterns are specified in the first region of `apply_conversion_patterns`. They must implement the `ConversionPatternDescriptorOpInterface`. Regular rewrite patterns and dialect conversion patterns should not be mixed, so the interface is separate from the `PatternDescriptorOpInterface`.
The type converter is specified as the single op of the second region. It is optional; if no type converter is specified, it is expected that pattern descriptors provide their own type converters. If both the pattern descriptors and the `apply_conversion_patterns` op specify a type converter, the type converter of the pattern descriptor is used.
Differential Revision: https://reviews.llvm.org/D157109
This function allows users to update payload op mappings in cases where such replacements cannot be performed automatically by the rewriter/listener interface.
Differential Revision: https://reviews.llvm.org/D153764
When exiting the scope of a region attached to a transform op, clean up
the handle invalidation checks assocaited with handles defined in this
region. Otherwise, these checks may trigger on the next entry to the
region while there is no incorrect usage.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D153545
Similar to operation handles, merging handles for other types can be useful to
avoid repetition of common transformations across a set of parameters.
For example, forming a list of static values for comparison rather than
comparing the parameters one at a time.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D153240
All `apply` functions now have a `TransformRewriter &` parameter. This rewriter should be used to modify the IR. It has a `TrackingListener` attached and updates the internal handle-payload mappings based on rewrites.
Implementations no longer need to create their own `TrackingListener` and `IRRewriter`. Error checking is integrated into `applyTransform`. Tracking listener errors are reported only for ops with the `ReportTrackingListenerFailuresOpTrait` trait attached, allowing for a gradual migration. Furthermore, errors can be silenced with an op attribute.
Additional API will be added to `TransformRewriter` in subsequent revisions. This revision just adds an "empty" `TransformRewriter` class and updates all `apply` implementations.
Differential Revision: https://reviews.llvm.org/D152427
ApplyEachOpTrait applies to payload ops associated with its operand
handle one-by-one in order. If a handle is consumed, this usually
indicates that the associated payload ops are erased or rewritten. Add a
check that we don't consume an ancestor payload operation before
consuming its descendant, as the latter is likely to be a dangling
pointer. Transform operations for which this is a legitimate behavior
(i.e., they consume the handle but don't actually erase or rewrite the
payload operation) should implement the interface directly and allow for
repeated handles.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D152510
Use the default TrackingListener. No need to set up a derived listener just for the test case. This revision is in preparation of a future change that adds a TrackingRewriter infrastructure.
Differential Revision: https://reviews.llvm.org/D152446
Patterns should be selected by adding ops that implement `PatternDescriptorOpInterface` to the region of `apply_pattern` ops. Such ops can have operands, allowing for pattern parameterization. The existing way of selecting patterns from the PatternRegistry is deprecated.
Differential Revision: https://reviews.llvm.org/D152167
Transform operations may indicate that they may accept and consume
several handles pointing to the same or nested payload entities. The
initial implementation of the expensive-checks mode was simply ignoring
such cases as consuming the second handle would fail the check after the
first handle invalidated it by consuming the same payload. Additional
checks had been added since then, which could now trigger assertions in
the expensive-checks module itself (instead of or in addition to
use-after-free assertions down the road), specifically because the
payload associations for invalidated handles is removed from the state
to enable other kinds of checking.
Rework the handling of transform operations with repeated handles so
use-after-consume is still reported properly if the consumption happened
by a preceding operation, as opposed to the a preceding operand of the
same operation that is still (corretly) ignored if the op requests that.
Depends on: D151560
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D151569
The transform dialect interpreter features the expensive-checks mode
that acts as an embedded sanitizer to track use-after-consume of
transform handles. Its logic is based on the relations between payload
operations, which made it silently ignore empty handles that are
consumed. Also catch and report this case because the remaining code may
hit an assertion on attempting to access a consumed handle (that is
removed from the mapping).
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D151560
Update operations in Transform dialect extensions used for testing to
use the more generic `TransformHandleTypeInterface` type constraint
instead of hardcoding `PDL_Operation`. See
https://discourse.llvm.org/t/rfc-type-system-for-the-transform-dialect/65702
for motivation. This is particularly important as these tests are often
used as source of best practices.
Update tests to use `!transform.any_op` instead of `!pdl.operation`.
Depends On D150785
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D150786
All ops now support explicit type specification, update types to use
`!transform.any_op` instead of `!pdl.operation` for consistency.
Depends On D144515
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D150592
Instead of returning an `ArrayRef<Operation *>`, return at iterator that skips ops that were erased/replaced while iterating over the payload ops.
This fixes an issue in conjuction with TrackingListener, where a tracked op was erased during the iteration. Elements may not be removed from an array while iterating over it; this invalidates the iterator.
When ops are erased/removed via `replacePayloadOp`, they are not immediately removed from the mappings data structure. Instead, they are set to `nullptr`. `nullptr`s are not enumerated by `getPayloadOps`. At the end of each transformation, `nullptr`s are removed from the mapping data structure.
Differential Revision: https://reviews.llvm.org/D149847
Add a set of transform operations into the "structured" extension of the
Transform dialect that allow one to select transformation targets more
specifically than the currently available matching. In particular, add
the mechanism for identifying the producers of operands (input and init
in destination-passing style) and users of results, as well as
mechanisms for reasoning about the shape of the iteration space.
Additionally, add several transform operations to manipulate parameters
that could be useful to implement more advanced selectors. Specifically,
new operations let one produce and compare parameter values to implement
shape-driven transformations.
New operations are placed in separate files to decrease compilation
time. Some relayering of the extension is necessary to avoid repeated
generation of enums.
Depends on D148013
Depends on D148014
Depends on D148015
Reviewed By: chelini
Differential Revision: https://reviews.llvm.org/D148017
Add a new transform op combinator that implements an "if-then-else"
style of mechanism for applying transformations. Its main purpose is to
serve as a higher-level driver when applying multiple transform scripts
to potentially overlapping pieces of the payload IR. This is similar to
how the various rewrite drivers operate in C++, but at a higher level
and with more declarative expressions. This is not intended to replace
existing pattern-based rewrites, but to to drive more complex
transformations that are exposed in the transform dialect and are too
complex to be expressed as simple declarative rewrites.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D148013
This revision adds additional "expensive-checks" checks to the transform dialect that detect the most common cases of:
* Missing `consumesHandle` side effects on transform ops.
* Patterns that remove operations but do not notify the transform dialect.
In essence, these additional checks are looking for dangling pointers to erased payload ops in the transform dialect state and crash the program execution (by dereferencing free'd memory) or triggering an assertion failure. It is recommended to run these extra checks with ASAN. Otherwise, certain failures may not be detected. The ASAN error message can also be used to find the faulty transform op/pattern.
This change also fixes a few faulty transform ops.
Differential Revision: https://reviews.llvm.org/D147447
Previous changes in 98acd7468307b6099e7deae206a749af324ff95f were overly
eager to disallow null payload everywhere. The semantics of
TransformEachOpTrait allows individual applications to return null
payloads as means of filtering out the operations to which they are not
applicable without emitting even a silenceable failure. This is a
questionable choice, but one apparently relied upon. Null payloads are
not supposed to leak outside of the trait.
Reviewed By: qcolombet
Differential Revision: https://reviews.llvm.org/D143904
Introduce support for the third kind of values in the transform dialect:
value handles. Similarly to operation handles, value handles are
pointing to a set of values in the payload IR. This enables
transformation to be targeted at specific values, such as individual
results of a multi-result payload operation without indirecting through
the producing op or block arguments that previously could not be easily
addressed. This is expected to support a broad class of memory-oriented
transformations such as selective bufferization, buffer assignment, and
memory transfer management.
Value handles are functionally similar to operation handles and require
similar implementation logic. The most important change concerns the
handle invalidation mechanism where operation and value handles can
affect each other.
This patch includes two cleanups that make it easier to introduce value
handles:
- `RaggedArray` structure that encapsulates the SmallVector of
ArrayRef backed by flat SmallVector logic, frequently used in the
transform interfaces implementation;
- rewrite the tests that associated payload handles with an integer
value `reinterpret_cast`ed as a pointer, which were a frequent
source of confusion and crashes when adding more debugging
facilities that can inspect the payload.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D143385
Add a verifier checking that if a transform operation consumes a handle
(which is associated with a payload operation being erased or
recreated), it also indicates modification of the payload IR. This
hasn't been consistent in the past because of the "no-aliasing"
assumption where we couldn't have had more than one handle to an
operation, requiring some handle-manipulation operations, such as
`transform.merge_handles` to consume their operands. That assumption has
been liften and it is no longer necessary for these operations to
consume handles and thus make the life harder for the clients.
Additionally, remove TransformEffects.td that uses the ODS mechanism for
indicating side effects that works only for operands and results. It
was being used incorrectly to also indicate effects on the payload IR,
not assocaited with any IR value, and lacked the consume/produce
semantics available via helpers in C++.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D142361
Add a verifier to the TransformOpInterface ensuring that operations
implementing the interface define memory effects on their operands and
results.
Add the missing effects to TileToForeachThreadOp, specifically for
operands that were added at a later version of the op without modifying
`getEffects` accordingly.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D141371
When establishing the correspondence between transform values and
payload operations or parameters, check that the latter are non-null and
report errors. This was previously allowed for exotic cases of partially
successfull transformations with "apply each" trait, but was dangerous.
The "apply each" implementation was reworked to remove the need for this
functionality, so this can now be hardned to avoid null pointer
dereferences.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D141142
Adapt the implementation of TransformEachOpTrait to the existence of
parameter values recently introduced into the transform dialect. In
particular, allow `applyToOne` hooks to return a list containing a mix
of `Operation *` that will be associated with handles and `Attribute`
that will be associated with parameter values by the trait
implementation of the transform interface's `apply` method.
Disentangle the "transposition" of the list of per-payload op partial
results to decrease its overall complexity and detemplatize the code
that doesn't really need templates. This removes the poorly documented
special handling for single-result ops with TransformEachOpTrait that
could have assigned null pointer values to handles.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D140979
This makes it more consistent with the recently added
TransformParamTypeInterface.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D140977
Introduce a new kind of values into the transform dialect -- parameter
values. These values have a type implementing the new
`TransformParamTypeInterface` and are associated with lists of
attributes rather than lists of payload operations. This mechanism
allows one to wrap numeric calculations, typically heuristics, into
transform operations separate from those at actually applying the
transformation. For example, tile size computation can be now separated
from tiling itself, and not hardcoded in the transform dialect. This
further improves the separation of concerns between transform choice and
implementation.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D140976
This is generated by running
```
sed --in-place 's/[[:space:]]\+$//' mlir/**/*.td
sed --in-place 's/[[:space:]]\+$//' mlir/**/*.mlir
```
Reviewed By: rriddle, dcaballe
Differential Revision: https://reviews.llvm.org/D138866
This patch takes the first step towards a more principled modeling of undefined behavior in MLIR as discussed in the following discourse threads:
1. https://discourse.llvm.org/t/semantics-modeling-undefined-behavior-and-side-effects/4812
2. https://discourse.llvm.org/t/rfc-mark-tensor-dim-and-memref-dim-as-side-effecting/65729
This patch in particular does the following:
1. Introduces a ConditionallySpeculatable OpInterface that dynamically determines whether an Operation can be speculated.
2. Re-defines `NoSideEffect` to allow undefined behavior, making it necessary but not sufficient for speculation. Also renames it to `NoMemoryEffect`.
3. Makes LICM respect the above semantics.
4. Changes all ops tagged with `NoSideEffect` today to additionally implement ConditionallySpeculatable and mark themselves as always speculatable. This combined trait is named `Pure`. This makes this change NFC.
For out of tree dialects:
1. Replace `NoSideEffect` with `Pure` if the operation does not have any memory effects, undefined behavior or infinite loops.
2. Replace `NoSideEffect` with `NoSideEffect` otherwise.
The next steps in this process are (I'm proposing to do these in upcoming patches):
1. Update operations like `tensor.dim`, `memref.dim`, `scf.for`, `affine.for` to implement a correct hook for `ConditionallySpeculatable`. I'm also happy to update ops in other dialects if the respective dialect owners would like to and can give me some pointers.
2. Update other passes that speculate operations to consult `ConditionallySpeculatable` in addition to `NoMemoryEffect`. I could not find any other than LICM on a quick skim, but I could have missed some.
3. Add some documentation / FAQs detailing the differences between side effects, undefined behavior, speculatabilty.
Reviewed By: rriddle, mehdi_amini
Differential Revision: https://reviews.llvm.org/D135505
Introduce a type system for the transform dialect. A transform IR type
captures the expectations of the transform IR on the payload IR
operations that are being transformed, such as being of a certain kind
or implementing an interface that enables the transformation. This
provides stricter checking and better readability of the transform IR
than using the catch-all "handle" type.
This change implements the basic support for a type system amendable to
dialect extensions and adds a drop-in replacement for the unrestricted
"handle" type. The actual switch of transform dialect ops to that type
will happen in a separate commit.
See https://discourse.llvm.org/t/rfc-type-system-for-the-transform-dialect/65702
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D135164
Relax the restriction in the transform dialect interpreter utilities
that expected a payload IR op to be assocaited with at most one
transform IR handle value. This was useful during the initial
bootstrapping to avoid use-after-free error equivalents when a payload
IR op could be erased through one of the handles associated with it and
then accessed through another. It was, however, possible to erase an
ancestor of the payload IR operation in question. The expensive-checks
mode of interpretation is able to detect both cases and has proven
sufficiently robust in debugging use-after-free errors.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D134964
A recent commit introduced helper functions with semantically meaningful names
to populate the lists of memory effects in transform ops, use them whenever
possible.
Depends On D129287
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D129365
This handle manipulation operation allows one to define a new handle that is
associated with a the same payload IR operations N times, where N can be driven
by the size of payload IR operation list associated with another handle. This
can be seen as a sort of broadcast that can be used to ensure the lists
associated with two handles have equal numbers of payload IR ops as expected by
many pairwise transform operations.
Introduce an additional "expensive" check that guards against consuming a
handle that is assocaited with the same payload IR operation more than once as
this is likely to lead to double-free or other undesired effects.
Depends On D129110
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D129216
This revision revisits the implementation of applyToOne and its handling
of recoverable errors as well as propagation of null handles.
The implementation is simplified to always require passing a vector<Operation*>
in which the results are returned, resulting in less template instantiation magic.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D129185
The result of applying an N-result producing transformation to M payload ops
is an M-wide result, each containing N result operations.
This requires a transposition of the results obtained by calling `applyToOne`.
This revision fixes the issue and adds more advanced tests that exercise the behavior.
Differential Revision: https://reviews.llvm.org/D128414
This revision separates the `LinalgSplitReduction` pattern, whose application is based on attributes,
from its implementation.
A transform dialect op extension is added to control the application of the transformation at a finer granularity.
Differential Revision: https://reviews.llvm.org/D128165
Introduce a transform dialect op that allows one to attempt different
transformation sequences on the same piece of payload IR until one of them
succeeds. This op fundamentally expands the scope of possibilities in the
transform dialect that, until now, could only propagate transformation failure,
at least using in-tree operations. This requires a more detailed specification
of the execution model for the transform dialect that now indicates how failure
is handled and propagated.
Transformations described by transform operations now have tri-state results,
with some errors being fundamentally irrecoverable (e.g., generating malformed
IR) and some others being recoverable by containing ops. Existing transform ops
directly implementing the `apply` interface method are updated to produce this
directly. Transform ops with the `TransformEachTransformOpTrait` are currently
considered to produce only irrecoverable failures and will be updated
separately.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D127724
In the transform dialect, a transform IR handle may be pointing to a payload IR
operation that is an ancestor of another payload IR operation pointed to by
another handle. If such a "parent" handle is consumed by a transformation, this
indicates that the associated operation is likely rewritten, which in turn
means that the "child" handle may now be associated with a dangling pointer or
a pointer to a different operation than originally. Add a handle invalidation
mechanism to guard against such situations by reporting errors at runtime.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D127480
The Transform dialect uses the side effect modeling mechanism to record the
effects of the transform ops on the mapping between Transform IR values and
Payload IR ops. Introduce a checker pass that warns if a Transform IR value is
used after it has been freed (consumed). This pass is mostly intended as a
debugging aid in addition to the verification/assertion mechanisms in the
transform interpreter. It reports all potential use-after-free situations.
The implementation makes a series of simplifying assumptions to be simple and
conservative. A more advanced implementation would rely on the data flow-like
analysis associated with a side-effect resource rather than a value, which is
currently not supported by the analysis infrastructure.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D126381
Add the mechanism for TransformState extensions to update the mapping between
Transform IR values and Payload IR operations held by the state. The mechanism
is intentionally restrictive, similarly to how results of the transform op are
handled.
Introduce test ops that exercise a simple extension that maintains information
across the application of multiple transform ops.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D124778
Currently, the sequence of Transform dialect operations only supports a single
use of each operand (verified by the `transform.sequence` operation). This was
originally motivated by the need to guard against accessing a payload IR
operation associated with a transform IR value after this operation has likely
been rewritten by a transformation. However, not all Transform dialect
operations rewrite payload IR, in particular the "navigation" operation such as
`transform.pdl_match` do not.
Introduce memory effects to the Transform dialect operations to describe their
effect on the payload IR and the mapping between payload IR opreations and
transform IR values. Use these effects to replace the single-use rule, allowing
repeated reads and disallowing use-after-free, where operations with the "free"
effect are considered to "consume" the transform IR value and rewrite the
corresponding payload IR operations). As an additional improvement, this
enables code motion transformation on the transform IR itself.
Reviewed By: Mogball
Differential Revision: https://reviews.llvm.org/D124181
