Commit graph

188 commits

Author SHA1 Message Date
Mehdi Amini a6e8ed7776 Improve error message on pass registration failures to include the faulty pass name 2021-06-17 00:24:50 +00:00
Mehdi Amini c8a3f561eb Decouple registring passes from specifying argument/description
This patch changes the (not recommended) static registration API from:

 static PassRegistration<MyPass> reg("my-pass", "My Pass Description.");

to:

 static PassRegistration<MyPass> reg;

And the explicit registration from:

  void registerPass("my-pass", "My Pass Description.",
                    [] { return createMyPass(); });

To:

  void registerPass([] { return createMyPass(); });

It is expected that Pass implementations overrides the getArgument() method
instead. This will ensure that pipeline description can be printed and parsed
back.

Differential Revision: https://reviews.llvm.org/D104421
2021-06-16 23:41:50 +00:00
Chris Lattner a490ca8e01 [PassManager] Save compile time by not running the verifier unnecessarily. NFC
This changes the pass manager to not rerun the verifier when a pass says it
didn't change anything or after an OpToOpPassAdaptor, since neither of those
cases need verification (and if the pass lied, then there will be much larger
semantic problems than will be caught by the verifier).

This maintains behavior in EXPENSIVE_CHECKS mode.

Differential Revision: https://reviews.llvm.org/D104243
2021-06-14 11:43:52 -07:00
River Riddle 8800047707 [mlir-ir-printing] Prefix the dump message with the split marker(// -----)
This allows for better interaction with tools (such as mlir-lsp-server), as it separates the IR into separate modules for consecutive dumps.

Differential Revision: https://reviews.llvm.org/D104073
2021-06-10 17:34:50 -07:00
River Riddle fa51c5af5d [mlir] Resolve TODO and use the pass argument instead of the TypeID for registration
This simplifies various pieces of code that interact with the pass registry, e.g. this removes the need to register passes to get accurate pass pipelines descriptions when generating crash reproducers.

Differential Revision: https://reviews.llvm.org/D101880
2021-06-02 12:17:36 -07:00
River Riddle 92469ca027 [mlir] Refactor the implementation of pass crash reproducers
The current implementation has several key limitations and weirdness, e.g local reproducers don't support dynamic pass pipelines, error messages don't include the passes that failed, etc. This revision refactors the implementation to support more use cases, and also be much cleaner.

The main change in this revision, aside from moving the implementation out of Pass.cpp and into its own file, is the addition of a crash recovery pass instrumentation. For local reproducers, this instrumentation handles setting up the recovery context before executing each pass. For global reproducers, the instrumentation is used to provide a more detailed error message, containing information about which passes are running and on which operations.

Example of new message:

```
error: Failures have been detected while processing an MLIR pass pipeline
note: Pipeline failed while executing [`TestCrashRecoveryPass` on 'module' operation: @foo]: reproducer generated at `crash-recovery.mlir.tmp`
```

Differential Revision: https://reviews.llvm.org/D101854
2021-05-19 16:59:53 -07:00
River Riddle 64ce90e1af [mlir] Add a new print-ir-after-failure IR pass printing flag
This flag will print the IR after a pass only in the case where the pass failed. This can be useful to more easily view the invalid IR, without needing to print after every pass in the pipeline.

Differential Revision: https://reviews.llvm.org/D101853
2021-05-19 16:54:20 -07:00
Fabian Schuiki 33f908c428
[MLIR] Factor pass timing out into a dedicated timing manager
This factors out the pass timing code into a separate `TimingManager`
that can be plugged into the `PassManager` from the outside. Users are
able to provide their own implementation of this manager, and use it to
time additional code paths outside of the pass manager. Also allows for
multiple `PassManager`s to run and contribute to a single timing report.

More specifically, moves most of the existing infrastructure in
`Pass/PassTiming.cpp` into a new `Support/Timing.cpp` file and adds a
public interface in `Support/Timing.h`. The `PassTiming` instrumentation
becomes a wrapper around the new timing infrastructure which adapts the
instrumentation callbacks to the new timers.

Reviewed By: rriddle, lattner

Differential Revision: https://reviews.llvm.org/D100647
2021-05-12 18:14:51 +02:00
Fangrui Song 18839be9c5 [ADT] Remove StatisticBase and make NoopStatistic empty
In LLVM_ENABLE_STATS=0 builds, `llvm::Statistic` maps to `llvm::NoopStatistic`
but has 3 mostly unused pointers. GlobalOpt considers that the pointers can
potentially retain allocated objects, so GlobalOpt cannot optimize out the
`NoopStatistic` variables (see D69428 for more context), wasting 23KiB for stage
2 clang.

This patch makes `NoopStatistic` empty and thus reclaims the wasted space.  The
clang size is even smaller than applying D69428 (slightly smaller in both .bss and
.text).
```
# This means the D69428 optimization on clang is mostly nullified by this patch.
HEAD+D69428: size(.bss) = 0x0725a8
HEAD+D101211: size(.bss) = 0x072238

# bloaty - HEAD+D69428 vs HEAD+D101211
# With D101211, we also save a lot of string table space (.rodata).
    FILE SIZE        VM SIZE
 --------------  --------------
  -0.0%     -32  -0.0%     -24    .eh_frame
  -0.0%    -336  [ = ]       0    .symtab
  -0.0%    -360  [ = ]       0    .strtab
  [ = ]       0  -0.2%    -880    .bss
  -0.0% -2.11Ki  -0.0% -2.11Ki    .rodata
  -0.0% -2.89Ki  -0.0% -2.89Ki    .text
  -0.0% -5.71Ki  -0.0% -5.88Ki    TOTAL
```

Note: LoopFuse is a disabled pass. For now this patch adds
`#if LLVM_ENABLE_STATS` so `OptimizationRemarkMissed` is skipped in
LLVM_ENABLE_STATS==0 builds.  If these `OptimizationRemarkMissed` are useful in
LLVM_ENABLE_STATS==0 builds, we can replace `llvm::Statistic` with
`llvm::TrackingStatistic`, or use a different abstraction to keep track of the strings.

Similarly, skip the code in `mlir/lib/Pass/PassStatistics.cpp` which
calls `getName`/`getDesc`/`getValue`.

Reviewed By: lattner

Differential Revision: https://reviews.llvm.org/D101211
2021-04-26 16:47:32 -07:00
Nico Weber 297a5b7cbc [mlir] hopefully final round of iwyu fixes after ba7a92c01e 2021-04-21 11:03:06 -04:00
Sean Silva 0524a09cc7 [mlir] Tune error message for assertion.
This assertion can fire in the case of different contexts as well, which
is not difficult to do from Python bindings, for example.
2021-03-22 18:10:18 -07:00
River Riddle cde203e0f9 [mlir][Pass] Coalesce dynamic pass pipelines before running
This was missed when dynamic pass pipelines were added, and is necessary for maximizing the performance/parallelism potential of the pass pipeline.
2021-03-19 14:35:42 -07:00
Mehdi Amini b1aaed023e Enable Pass::initialize() to fail by returning a LogicalResult
Differential Revision: https://reviews.llvm.org/D96474
2021-02-11 01:51:53 +00:00
Alex Zinenko 2996a8d675 [mlir] avoid exposing mutable DialectRegistry from MLIRContext
MLIRContext allows its users to access directly to the DialectRegistry it
contains. While sometimes useful for registering additional dialects on an
already existing context, this breaks the encapsulation by essentially giving
raw accesses to a part of the context's internal state. Remove this mutable
access and instead provide a method to append a given DialectRegistry to the
one already contained in the context. Also provide a shortcut mechanism to
construct a context from an already existing registry, which seems to be a
common use case in the wild. Keep read-only access to the registry contained in
the context in case it needs to be copied or used for constructing another
context.

With this change, DialectRegistry is no longer concerned with loading the
dialects and deciding whether to invoke delayed interface registration. Loading
is concentrated in the MLIRContext, and the functionality of the registry
better reflects its name.

Depends On D96137

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D96331
2021-02-10 12:07:34 +01:00
River Riddle fe7c0d90b2 [mlir][IR] Remove the concept of OperationProperties
These properties were useful for a few things before traits had a better integration story, but don't really carry their weight well these days. Most of these properties are already checked via traits in most of the code. It is better to align the system around traits, and improve the performance/cost of traits in general.

Differential Revision: https://reviews.llvm.org/D96088
2021-02-09 12:00:15 -08:00
River Riddle e21adfa32d [mlir] Mark LogicalResult as LLVM_NODISCARD
This makes ignoring a result explicit by the user, and helps to prevent accidental errors with dropped results. Marking LogicalResult as no discard was always the intention from the beginning, but got lost along the way.

Differential Revision: https://reviews.llvm.org/D95841
2021-02-04 15:10:10 -08:00
River Riddle 02bc4c95f0 [mlir][PassManager] Only reinitialize the pass manager if the context registry changes
This prevents needless reinitialization for clients that want to reuse a pass manager multiple times. A new `getRegisryHash` function is exposed by the context to give a rough indicator of when the context registry has changed.

Differential Revision: https://reviews.llvm.org/D95493
2021-01-27 17:41:51 -08:00
Jacques Pienaar aee622fa20 [mlir] Enable passing crash reproducer stream factory method
Add factory to create streams for logging the reproducer. Allows for more general logging (beyond file) and logging the configuration/module separately (logged in order, configuration before module).

Also enable querying filename of ToolOutputFile.

Differential Revision: https://reviews.llvm.org/D94868
2021-01-21 20:03:15 -08:00
River Riddle 77501bd175 [mlir][PassManager] Properly set the initialization generation when cloning a pass manager
Fixes a bug where dynamic pass pipelines of cloned pass managers weren't being initialized properly.
2021-01-08 14:41:29 -08:00
River Riddle 1ba5ea67a3 [mlir] Add a hook for initializing passes before execution and use it in the Canonicalizer
This revision adds a new `initialize(MLIRContext *)` hook to passes that allows for them to initialize any heavy state before the first execution of the pass. A concrete use case of this is with patterns that rely on PDL, given that PDL is compiled at run time it is imperative that compilation results are cached as much as possible. The first use of this hook is in the Canonicalizer, which has the added benefit of reducing the number of expensive accesses to the context when collecting patterns.

Differential Revision: https://reviews.llvm.org/D93147
2021-01-08 13:36:12 -08:00
Jacques Pienaar 5fd2b3a124 [mlir] Add error message when failing to add pass
Ran into failure without any error message previously here.

Differential Revision: https://reviews.llvm.org/D93910
2020-12-29 14:20:19 -08:00
River Riddle fc5cf50e89 [mlir] Remove the MutableDictionaryAttr class
This class used to serve a few useful purposes:
* Allowed containing a null DictionaryAttr
* Provided some simple mutable API around a DictionaryAttr

The first of which is no longer an issue now that there is much better caching support for attributes in general, and a cache in the context for empty dictionaries. The second results in more trouble than it's worth because it mutates the internal dictionary on every action, leading to a potentially large number of dictionary copies. NamedAttrList is a much better alternative for the second use case, and should be modified as needed to better fit it's usage as a DictionaryAttrBuilder.

Differential Revision: https://reviews.llvm.org/D93442
2020-12-17 17:18:42 -08:00
River Riddle e9cda7c5a0 [mlir][Pass] Add a new PassNameCLParser specifically for parsing lists of pass names
This parser does not include the general `pass_pipeline` option, the pass pipeline entries, or the options of pass entries. This is useful for cases such as `print-ir-after` that just want the user to select specific pass types. This revision greatly reduces the amount of text in --help for several MLIR based tools.

Fixes PR#45495

Differential Revision: https://reviews.llvm.org/D92987
2020-12-15 14:56:09 -08:00
River Riddle d7eba20052 [mlir][Inliner] Refactor the inliner to use nested pass pipelines instead of just canonicalization
Now that passes have support for running nested pipelines, the inliner can now allow for users to provide proper nested pipelines to use for optimization during inlining. This revision also changes the behavior of optimization during inlining to optimize before attempting to inline, which should lead to a more accurate cost model and prevents the need for users to schedule additional duplicate cleanup passes before/after the inliner that would already be run during inlining.

Differential Revision: https://reviews.llvm.org/D91211
2020-12-14 18:09:47 -08:00
Jacques Pienaar 9c3fa3d84d Don't emit on op diagnostic in reproducer emission
This avoids dumping the module post emitting a reproducer, which results in
many MB logs where a reproducer has already been neatly generated.

Differential Revision: https://reviews.llvm.org/D93165
2020-12-13 07:21:32 -08:00
River Riddle 00c6ef8628 [mlir][Pass] Remove the restriction that PassManager can only run on ModuleOp
This was a somewhat important restriction in the past when ModuleOp was distinctly the top-level container operation, as well as before the pass manager had support for running nested pass managers natively. With these two issues fading away, there isn't really a good reason to enforce that a ModuleOp is the thing running within a pass manager. As such, this revision removes the restriction and allows for users to pass in the name of the operation that the pass manager will be scheduled on.

The only remaining dependency on BuiltinOps from Pass after this revision is due to FunctionPass, which will be resolved in a followup revision.

Differential Revision: https://reviews.llvm.org/D92450
2020-12-03 15:47:01 -08:00
River Riddle 65fcddff24 [mlir][BuiltinDialect] Resolve comments from D91571
* Move ops to a BuiltinOps.h
* Add file comments
2020-11-19 11:12:49 -08:00
River Riddle bd106d7469 [mlir][Pass] Only enable/disable CrashRecovery once
This prevents potential problems that occur when multiple pass managers register crash recovery contexts.
2020-11-18 18:50:18 -08:00
River Riddle 73ca690df8 [mlir][NFC] Remove references to Module.h and Function.h
These includes have been deprecated in favor of BuiltinDialect.h, which contains the definitions of ModuleOp and FuncOp.

Differential Revision: https://reviews.llvm.org/D91572
2020-11-17 00:55:47 -08:00
River Riddle 811001380f [mlir][Pass] Remove the verifierPass now that verification is run during normal pass execution
A recent refactoring removed the need to interleave verifier passes and instead opted to verify during the normal execution of passes instead. As such, the old verify pass is no longer necessary and can be removed.

Differential Revision: https://reviews.llvm.org/D91212
2020-11-12 23:45:27 -08:00
Mehdi Amini a62d38a90d Disable implicit nesting on parsing textual pass pipeline
Previous the textual form of the pass pipeline would implicitly nest,
instead we opt for the explicit form here: this has less surprise.

This also avoids asserting in the bindings when passing a pass pipeline
with incorrect nesting.

Differential Revision: https://reviews.llvm.org/D91233
2020-11-11 19:21:51 +00:00
Mehdi Amini 4455f3ce72 Capture the name for mlir::OpPassManager in std::string instead of StringRef (NFC)
The previous behavior was fragile when building an OpPassManager using a
string, as it was forcing the client to ensure the string to outlive the
entire PassManager.
This isn't a performance sensitive area either that would justify
optimizing further.
2020-11-05 05:28:44 +00:00
Mehdi Amini 008b9d97cb Make the implicit nesting behavior of the PassManager user-controllable and default to false
This is an error prone behavior, I frequently have ~20 min debugging sessions when I hit
an unexpected implicit nesting. This default makes the C++ API safer for users.

Depends On D90669

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D90671
2020-11-03 11:17:44 +00:00
Mehdi Amini cd7107a62b Handle the verifier at run() time in the PassManager instead of build time
This simplifies a few parts of the pass manager, but in particular we don't add as many
verifierpass as there are passes in the pipeline, and we can now enable/disable the
verifier after the fact on an already built PassManager.

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D90669
2020-11-03 11:17:14 +00:00
Mehdi Amini fe3c1195cf Add a dump() method on the pass manager for debugging purpose (NFC)
Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D88008
2020-09-23 05:53:41 +00:00
Mehdi Amini fb1de7ed92 Implement a new kind of Pass: dynamic pass pipeline
Instead of performing a transformation, such pass yields a new pass pipeline
to run on the currently visited operation.
This feature can be used for example to implement a sub-pipeline that
would run only on an operation with specific attributes. Another example
would be to compute a cost model and dynamic schedule a pipeline based
on the result of this analysis.

Discussion: https://llvm.discourse.group/t/rfc-dynamic-pass-pipeline/1637

Recommit after fixing an ASAN issue: the callback lambda needs to be
allocated to a temporary to have its lifetime extended to the end of the
current block instead of just the current call expression.

Reviewed By: silvas

Differential Revision: https://reviews.llvm.org/D86392
2020-09-22 18:51:54 +00:00
Thomas Joerg 0356a413a4 Revert "Implement a new kind of Pass: dynamic pass pipeline"
This reverts commit 385c3f43fc.

Test  mlir/test/Pass:dynamic-pipeline-fail-on-parent.mlir.test fails
when run with ASAN:

ERROR: AddressSanitizer: stack-use-after-scope on address ...

Reviewed By: bkramer, pifon2a

Differential Revision: https://reviews.llvm.org/D88079
2020-09-22 12:00:30 +02:00
Mehdi Amini 385c3f43fc Implement a new kind of Pass: dynamic pass pipeline
Instead of performing a transformation, such pass yields a new pass pipeline
to run on the currently visited operation.
This feature can be used for example to implement a sub-pipeline that
would run only on an operation with specific attributes. Another example
would be to compute a cost model and dynamic schedule a pipeline based
on the result of this analysis.

Discussion: https://llvm.discourse.group/t/rfc-dynamic-pass-pipeline/1637

Reviewed By: silvas

Differential Revision: https://reviews.llvm.org/D86392
2020-09-22 01:24:25 +00:00
Mehdi Amini 702f06ad14 Fix crash in the pass pipeline when local reproducer is enabled
This crash only happens when a function pass is followed by a module
pass. In this case the splitting of the pass pipeline didn't handle
properly the verifier passes and ended up with an odd number of pass in
the pipeline, breaking an assumption of the local crash reproducer
executor and hitting an assertion.

Differential Revision: https://reviews.llvm.org/D88000
2020-09-21 08:52:50 +00:00
Mehdi Amini c0b6bc070e Decouple OpPassManager from the the MLIRContext (NFC)
This is allowing to build an OpPassManager from a StringRef instead of an
Identifier, which enables building pipelines without an MLIRContext.
An identifier is still cached on-demand on the OpPassManager for efficiency
during the IR traversal.
2020-09-03 06:02:05 +00:00
Mehdi Amini 1284dc34ab Use an Identifier instead of an OperationName internally for OpPassManager identification (NFC)
This allows to defers the check for traits to the execution instead of forcing it on the pipeline creation.
In particular, this is making our pipeline creation tolerant to dialects not being loaded in the context yet.

Reviewed By: rriddle, GMNGeoffrey

Differential Revision: https://reviews.llvm.org/D86915
2020-09-02 21:46:05 +00:00
Mehdi Amini c39c21610d Rename AnalysisManager::slice in AnalysisManager::nest (NFC)
The naming wasn't reflecting the intent of this API, "nest" is aligning
it with the pass manager API.
2020-08-28 20:41:07 +00:00
Mehdi Amini 6c05ca21b9 Remove the run method from OpPassManager and Pass and migrate it to OpToOpPassAdaptor
This makes OpPassManager more of a "container" of passes and not responsible to drive the execution.
As such we also make it constructible publicly, which will allow to build arbitrary pipeline decoupled from the execution. We'll make use of this facility to expose "dynamic pipeline" in the future.

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D86391
2020-08-27 04:57:29 +00:00
Mehdi Amini 610706906a Add an assertion to protect against missing Dialect registration in a pass pipeline (NFC)
Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D86327
2020-08-24 06:49:29 +00:00
Mehdi Amini f9dc2b7079 Separate the Registration from Loading dialects in the Context
This changes the behavior of constructing MLIRContext to no longer load globally
registered dialects on construction. Instead Dialects are only loaded explicitly
on demand:
- the Parser is lazily loading Dialects in the context as it encounters them
during parsing. This is the only purpose for registering dialects and not load
them in the context.
- Passes are expected to declare the dialects they will create entity from
(Operations, Attributes, or Types), and the PassManager is loading Dialects into
the Context when starting a pipeline.

This changes simplifies the configuration of the registration: a compiler only
need to load the dialect for the IR it will emit, and the optimizer is
self-contained and load the required Dialects. For example in the Toy tutorial,
the compiler only needs to load the Toy dialect in the Context, all the others
(linalg, affine, std, LLVM, ...) are automatically loaded depending on the
optimization pipeline enabled.

To adjust to this change, stop using the existing dialect registration: the
global registry will be removed soon.

1) For passes, you need to override the method:

virtual void getDependentDialects(DialectRegistry &registry) const {}

and registery on the provided registry any dialect that this pass can produce.
Passes defined in TableGen can provide this list in the dependentDialects list
field.

2) For dialects, on construction you can register dependent dialects using the
provided MLIRContext: `context.getOrLoadDialect<DialectName>()`
This is useful if a dialect may canonicalize or have interfaces involving
another dialect.

3) For loading IR, dialect that can be in the input file must be explicitly
registered with the context. `MlirOptMain()` is taking an explicit registry for
this purpose. See how the standalone-opt.cpp example is setup:

  mlir::DialectRegistry registry;
  registry.insert<mlir::standalone::StandaloneDialect>();
  registry.insert<mlir::StandardOpsDialect>();

Only operations from these two dialects can be in the input file. To include all
of the dialects in MLIR Core, you can populate the registry this way:

  mlir::registerAllDialects(registry);

4) For `mlir-translate` callback, as well as frontend, Dialects can be loaded in
the context before emitting the IR: context.getOrLoadDialect<ToyDialect>()

Differential Revision: https://reviews.llvm.org/D85622
2020-08-19 01:19:03 +00:00
Mehdi Amini e75bc5c791 Revert "Separate the Registration from Loading dialects in the Context"
This reverts commit d14cf45735.
The build is broken with GCC-5.
2020-08-19 01:19:03 +00:00
Mehdi Amini d14cf45735 Separate the Registration from Loading dialects in the Context
This changes the behavior of constructing MLIRContext to no longer load globally
registered dialects on construction. Instead Dialects are only loaded explicitly
on demand:
- the Parser is lazily loading Dialects in the context as it encounters them
during parsing. This is the only purpose for registering dialects and not load
them in the context.
- Passes are expected to declare the dialects they will create entity from
(Operations, Attributes, or Types), and the PassManager is loading Dialects into
the Context when starting a pipeline.

This changes simplifies the configuration of the registration: a compiler only
need to load the dialect for the IR it will emit, and the optimizer is
self-contained and load the required Dialects. For example in the Toy tutorial,
the compiler only needs to load the Toy dialect in the Context, all the others
(linalg, affine, std, LLVM, ...) are automatically loaded depending on the
optimization pipeline enabled.

To adjust to this change, stop using the existing dialect registration: the
global registry will be removed soon.

1) For passes, you need to override the method:

virtual void getDependentDialects(DialectRegistry &registry) const {}

and registery on the provided registry any dialect that this pass can produce.
Passes defined in TableGen can provide this list in the dependentDialects list
field.

2) For dialects, on construction you can register dependent dialects using the
provided MLIRContext: `context.getOrLoadDialect<DialectName>()`
This is useful if a dialect may canonicalize or have interfaces involving
another dialect.

3) For loading IR, dialect that can be in the input file must be explicitly
registered with the context. `MlirOptMain()` is taking an explicit registry for
this purpose. See how the standalone-opt.cpp example is setup:

  mlir::DialectRegistry registry;
  registry.insert<mlir::standalone::StandaloneDialect>();
  registry.insert<mlir::StandardOpsDialect>();

Only operations from these two dialects can be in the input file. To include all
of the dialects in MLIR Core, you can populate the registry this way:

  mlir::registerAllDialects(registry);

4) For `mlir-translate` callback, as well as frontend, Dialects can be loaded in
the context before emitting the IR: context.getOrLoadDialect<ToyDialect>()

Differential Revision: https://reviews.llvm.org/D85622
2020-08-18 23:23:56 +00:00
Mehdi Amini d84fe55e0d Revert "Separate the Registration from Loading dialects in the Context"
This reverts commit e1de2b7550.
Broke a build bot.
2020-08-18 22:16:34 +00:00
Mehdi Amini e1de2b7550 Separate the Registration from Loading dialects in the Context
This changes the behavior of constructing MLIRContext to no longer load globally
registered dialects on construction. Instead Dialects are only loaded explicitly
on demand:
- the Parser is lazily loading Dialects in the context as it encounters them
during parsing. This is the only purpose for registering dialects and not load
them in the context.
- Passes are expected to declare the dialects they will create entity from
(Operations, Attributes, or Types), and the PassManager is loading Dialects into
the Context when starting a pipeline.

This changes simplifies the configuration of the registration: a compiler only
need to load the dialect for the IR it will emit, and the optimizer is
self-contained and load the required Dialects. For example in the Toy tutorial,
the compiler only needs to load the Toy dialect in the Context, all the others
(linalg, affine, std, LLVM, ...) are automatically loaded depending on the
optimization pipeline enabled.

To adjust to this change, stop using the existing dialect registration: the
global registry will be removed soon.

1) For passes, you need to override the method:

virtual void getDependentDialects(DialectRegistry &registry) const {}

and registery on the provided registry any dialect that this pass can produce.
Passes defined in TableGen can provide this list in the dependentDialects list
field.

2) For dialects, on construction you can register dependent dialects using the
provided MLIRContext: `context.getOrLoadDialect<DialectName>()`
This is useful if a dialect may canonicalize or have interfaces involving
another dialect.

3) For loading IR, dialect that can be in the input file must be explicitly
registered with the context. `MlirOptMain()` is taking an explicit registry for
this purpose. See how the standalone-opt.cpp example is setup:

  mlir::DialectRegistry registry;
  mlir::registerDialect<mlir::standalone::StandaloneDialect>();
  mlir::registerDialect<mlir::StandardOpsDialect>();

Only operations from these two dialects can be in the input file. To include all
of the dialects in MLIR Core, you can populate the registry this way:

  mlir::registerAllDialects(registry);

4) For `mlir-translate` callback, as well as frontend, Dialects can be loaded in
the context before emitting the IR: context.getOrLoadDialect<ToyDialect>()
2020-08-18 21:14:39 +00:00
Mehdi Amini 25ee851746 Revert "Separate the Registration from Loading dialects in the Context"
This reverts commit 2056393387.

Build is broken on a few bots
2020-08-15 09:21:47 +00:00