Commit Graph

51 Commits

Author SHA1 Message Date
Lei Zhang 3148f10b17 [mlir][spirv] Use spv.vce in spv.module and wire up (de)serialization
This commits changes the definition of spv.module to use the #spv.vce
attribute for specifying (version, capabilities, extensions) triple
so that we can have better API and custom assembly form. Since now
we have proper modelling of the triple, (de)serialization is wired up
to use them.

With the new UpdateVCEPass, we don't need to manually specify the
required extensions and capabilities anymore when creating a spv.module.
One just need to call UpdateVCEPass before serialization to get the
needed version/extensions/capabilities.

Differential Revision: https://reviews.llvm.org/D75872
2020-03-12 19:37:45 -04:00
Stephen Neuendorffer 4594d0e943 [MLIR] Move from add_dependencies() to DEPENDS
add_llvm_library and add_llvm_executable may need to create new targets with
appropriate dependencies.  As a result, it is not sufficient in some
configurations (namely LLVM_BUILD_LLVM_DYLIB=on) to only call
add_dependencies().  Instead, the explicit TableGen dependencies must
be passed to add_llvm_library() or add_llvm_executable() using the DEPENDS
keyword.

Differential Revision: https://reviews.llvm.org/D74930
2020-03-06 13:25:17 -08:00
Stephen Neuendorffer 1c82dd39f9 [MLIR] Ensure that target_link_libraries() always has a keyword.
CMake allows calling target_link_libraries() without a keyword,
but this usage is not preferred when also called with a keyword,
and has surprising behavior.  This patch explicitly specifies a
keyword when using target_link_libraries().

Differential Revision: https://reviews.llvm.org/D75725
2020-03-06 09:14:01 -08:00
Stephen Neuendorffer 798e661567 Revert "[MLIR] Move from using target_link_libraries to LINK_LIBS for llvm libraries."
This reverts commit 7a6c689771.
This breaks the build with cmake 3.13.4, but succeeds with cmake 3.15.3
2020-02-29 11:52:08 -08:00
Stephen Neuendorffer d675df0379 Revert "[MLIR] Move from add_dependencies() to DEPENDS"
This reverts commit 31e07d716a.
2020-02-29 11:52:08 -08:00
Stephen Neuendorffer 31e07d716a [MLIR] Move from add_dependencies() to DEPENDS
add_llvm_library and add_llvm_executable may need to create new targets with
appropriate dependencies.  As a result, it is not sufficient in some
configurations (namely LLVM_BUILD_LLVM_DYLIB=on) to only call
add_dependencies().  Instead, the explicit TableGen dependencies must
be passed to add_llvm_library() or add_llvm_executable() using the DEPENDS
keyword.

Differential Revision: https://reviews.llvm.org/D74930
2020-02-29 10:47:27 -08:00
Stephen Neuendorffer 7a6c689771 [MLIR] Move from using target_link_libraries to LINK_LIBS for llvm libraries.
When compiling libLLVM.so, add_llvm_library() manipulates the link libraries
being used.  This means that when using add_llvm_library(), we need to pass
the list of libraries to be linked (using the LINK_LIBS keyword) instead of
using the standard target_link_libraries call.  This is preparation for
properly dealing with creating libMLIR.so as well.

Differential Revision: https://reviews.llvm.org/D74864
2020-02-29 10:47:26 -08:00
Stephen Neuendorffer dc1056a3f1 Revert "[MLIR] Move from using target_link_libraries to LINK_LIBS for llvm libraries."
This reverts commit 2f265e3528.
2020-02-28 14:13:30 -08:00
Stephen Neuendorffer 67f2a43cf8 Revert "[MLIR] Move from add_dependencies() to DEPENDS"
This reverts commit 8a2b86b2c2.
2020-02-28 12:17:40 -08:00
Stephen Neuendorffer 8a2b86b2c2 [MLIR] Move from add_dependencies() to DEPENDS
add_llvm_library and add_llvm_executable may need to create new targets with
appropriate dependencies.  As a result, it is not sufficient in some
configurations (namely LLVM_BUILD_LLVM_DYLIB=on) to only call
add_dependencies().  Instead, the explicit TableGen dependencies must
be passed to add_llvm_library() or add_llvm_executable() using the DEPENDS
keyword.

Differential Revision: https://reviews.llvm.org/D74930
2020-02-28 11:35:18 -08:00
Stephen Neuendorffer 2f265e3528 [MLIR] Move from using target_link_libraries to LINK_LIBS for llvm libraries.
When compiling libLLVM.so, add_llvm_library() manipulates the link libraries
being used.  This means that when using add_llvm_library(), we need to pass
the list of libraries to be linked (using the LINK_LIBS keyword) instead of
using the standard target_link_libraries call.  This is preparation for
properly dealing with creating libMLIR.so as well.

Differential Revision: https://reviews.llvm.org/D74864
2020-02-28 11:35:17 -08:00
Stephen Neuendorffer c07fb9e016 [MLIR] Refactor library handling for conversions.
Collect a list of conversion libraries in cmake, so we don't have to
list these explicitly in most binaries.

Differential Revision: https://reviews.llvm.org/D75222
2020-02-28 11:35:17 -08:00
Nagy Mostafa bc7b26c333 [MLIR] Allow Loop dialect IfOp and ForOp to define values
This patch implements the RFCs proposed here:
https://llvm.discourse.group/t/rfc-modify-ifop-in-loop-dialect-to-yield-values/463
https://llvm.discourse.group/t/rfc-adding-operands-and-results-to-loop-for/459/19.

It introduces the following changes:
- All Loop Ops region, except for ReduceOp, terminate with a YieldOp.
- YieldOp can have variadice operands that is used to return values out of IfOp and ForOp regions.
- Change IfOp and ForOp syntax and representation to define values.
- Add unit-tests and update .td documentation.
- YieldOp is a terminator to loop.for/if/parallel
- YieldOp custom parser and printer

Lowering is not supported at the moment, and will be in a follow-up PR.

Thanks.

Reviewed By: bondhugula, nicolasvasilache, rriddle

Differential Revision: https://reviews.llvm.org/D74174
2020-02-21 10:05:32 -08:00
Lei Zhang d3e7816d85 [mlir][spirv] Introduce spv.func
Thus far we have been using builtin func op to model SPIR-V functions.
It was because builtin func op used to have special treatment in
various parts of the core codebase (e.g., pass pipelines, etc.) and
it's easy to bootstrap the development of the SPIR-V dialect. But
nowadays with general op concepts and region support we don't have
such limitations and it's time to tighten the SPIR-V dialect for
completeness.

This commits introduces a spv.func op to properly model SPIR-V
functions. Compared to builtin func op, it can provide the following
benefits:

* We can control the full op so we can integrate SPIR-V information
  bits (e.g., function control) in a more integrated way and define
  our own assembly form and enforcing better verification.
* We can have a better dialect and library boundary. At the current
  moment only functions are modelled with an external op. With this
  change, all ops modelling SPIR-V concpets will be spv.* ops and
  registered to the SPIR-V dialect.
* We don't need to special-case func op anymore when creating
  ConversionTarget declaring SPIR-V dialect as legal. This is quite
  important given we'll see more and more conversions in the future.

In the process, bumps a few FuncOp methods to the FunctionLike trait.

Differential Revision: https://reviews.llvm.org/D74226
2020-02-12 07:46:43 -05:00
Lei Zhang 50aeeed8a2 [mlir][spirv] Use spv.entry_point_abi in GPU to SPIR-V conversions
We have spv.entry_point_abi for specifying the local workgroup size.
It should be decorated onto input gpu.func ops to drive the SPIR-V
CodeGen to generate the proper SPIR-V module execution mode. Compared
to using command-line options for specifying the configuration, using
attributes also has the benefits that 1) we are now able to use
different local workgroup for different entry points and 2) the
tests contains the configuration directly.

Differential Revision: https://reviews.llvm.org/D74012
2020-02-10 16:24:48 -05:00
MaheshRavishankar aaddca1efd [mlir][GPUToSPIRV] Modify the lowering of gpu.block_dim to be consistent with Vulkan SPEC
The existing lowering of gpu.block_dim added a global variable with
the WorkGroupSize decoration. This raises an error within
Vulkan/SPIR-V validation since Vulkan requires this to have a constant
initializer. This is not yet supported in SPIR-V dialect. Changing the
lowering to return the workgroup size as a constant value instead,
obtained from spv.entry_point_abi attribute gets around the issue for
now. The validation goes through since the workgroup size is specified
using spv.execution_mode operation.
2020-02-08 22:30:03 -08:00
Mehdi Amini 308571074c Mass update the MLIR license header to mention "Part of the LLVM project"
This is an artifact from merging MLIR into LLVM, the file headers are
now aligned with the rest of the project.
2020-01-26 03:58:30 +00:00
Tres Popp 9a52ea5cf9 Create a gpu.module operation for the GPU Dialect.
Summary:
This is based on the use of code constantly checking for an attribute on
a model and instead represents the distinct operaion with a different
op. Instead, this op can be used to provide better filtering.

Reverts "Revert "[mlir] Create a gpu.module operation for the GPU Dialect.""

This reverts commit ac446302ca4145cdc89f377c0c364c29ee303be5 after
fixing internal Google issues.

This additionally updates ROCDL lowering to use the new gpu.module.

Reviewers: herhut, mravishankar, antiagainst, nicolasvasilache

Subscribers: jholewinski, mgorny, mehdi_amini, jpienaar, burmako, shauheen, csigg, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, llvm-commits, mravishankar, rriddle, antiagainst, bkramer

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72921
2020-01-21 14:05:03 +01:00
Denis Khalikov 29779894af [mlir][spirv] Add lowering from `loop.if` to `spv.selection`
When lowering `loop.if` to `spv.selection` we explicitly create
a selection header block before the control flow diverges and a
merge block where control flow subsequently converges.

Differential Revision: https://reviews.llvm.org/D72836
2020-01-17 12:04:12 -05:00
Benjamin Kramer 0133cc60e4 Revert "[mlir] Create a gpu.module operation for the GPU Dialect."
This reverts commit 4624a1e8ac. Causing
problems downstream.
2020-01-15 17:52:17 +01:00
Lei Zhang 47c6ab2b97 [mlir][spirv] Properly support SPIR-V conversion target
This commit defines a new SPIR-V dialect attribute for specifying
a SPIR-V target environment. It is a dictionary attribute containing
the SPIR-V version, supported extension list, and allowed capability
list. A SPIRVConversionTarget subclass is created to take in the
target environment and sets proper dynmaically legal ops by querying
the op availability interface of SPIR-V ops to make sure they are
available in the specified target environment. All existing conversions
targeting SPIR-V is changed to use this SPIRVConversionTarget. It
probes whether the input IR has a `spv.target_env` attribute,
otherwise, it uses the default target environment: SPIR-V 1.0 with
Shader capability and no extra extensions.

Differential Revision: https://reviews.llvm.org/D72256
2020-01-14 19:18:42 -05:00
Tres Popp 4624a1e8ac [mlir] Create a gpu.module operation for the GPU Dialect.
Summary:
This is based on the use of code constantly checking for an attribute on
a model and instead represents the distinct operaion with a different
op. Instead, this op can be used to provide better filtering.

Reviewers: herhut, mravishankar, antiagainst, rriddle

Reviewed By: herhut, antiagainst, rriddle

Subscribers: liufengdb, aartbik, jholewinski, mgorny, mehdi_amini, rriddle, jpienaar, burmako, shauheen, antiagainst, nicolasvasilache, csigg, arpith-jacob, mgester, lucyrfox, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72336
2020-01-14 12:05:47 +01:00
River Riddle 2bdf33cc4c [mlir] NFC: Remove Value::operator* and Value::operator-> now that Value is properly value-typed.
Summary: These were temporary methods used to simplify the transition.

Reviewed By: antiagainst

Differential Revision: https://reviews.llvm.org/D72548
2020-01-11 08:54:39 -08:00
River Riddle 21610e6651 Refactor the way that pass options are specified.
This change refactors pass options to be more similar to how statistics are modeled. More specifically, the options are specified directly on the pass instead of in a separate options class. (Note that the behavior and specification for pass pipelines remains the same.) This brings about several benefits:
* The specification of options is much simpler
* The round-trip format of a pass can be generated automatically
* This gives a somewhat deeper integration with "configuring" a pass, which we could potentially expose to users in the future.

PiperOrigin-RevId: 286953824
2019-12-23 16:48:22 -08:00
River Riddle e62a69561f NFC: Replace ValuePtr with Value and remove it now that Value is value-typed.
ValuePtr was a temporary typedef during the transition to a value-typed Value.

PiperOrigin-RevId: 286945714
2019-12-23 16:36:53 -08:00
Mehdi Amini 56222a0694 Adjust License.txt file to use the LLVM license
PiperOrigin-RevId: 286906740
2019-12-23 15:33:37 -08:00
River Riddle 35807bc4c5 NFC: Introduce new ValuePtr/ValueRef typedefs to simplify the transition to Value being value-typed.
This is an initial step to refactoring the representation of OpResult as proposed in: https://groups.google.com/a/tensorflow.org/g/mlir/c/XXzzKhqqF_0/m/v6bKb08WCgAJ

This change will make it much simpler to incrementally transition all of the existing code to use value-typed semantics.

PiperOrigin-RevId: 286844725
2019-12-22 22:00:23 -08:00
River Riddle 2666b97314 NFC: Cleanup non-conforming usages of namespaces.
* Fixes use of anonymous namespace for static methods.
* Uses explicit qualifiers(mlir::) instead of wrapping the definition with the namespace.

PiperOrigin-RevId: 286222654
2019-12-18 10:46:48 -08:00
Mahesh Ravishankar 80ec474a65 Add atomic operations to SPIR-V dialect.
Some changes to the dialect generation script to allow specification
of different base class to derive from in ODS.

PiperOrigin-RevId: 285859230
2019-12-16 15:05:51 -08:00
Alex Zinenko 6273fa0c6a Plug gpu.func into the GPU lowering pipelines
This updates the lowering pipelines from the GPU dialect to lower-level
dialects (NVVM, SPIRV) to use the recently introduced gpu.func operation
instead of a standard function annotated with an attribute. In particular, the
kernel outlining is updated to produce gpu.func instead of std.func and the
individual conversions are updated to consume gpu.funcs and disallow standard
funcs after legalization, if necessary. The attribute "gpu.kernel" is preserved
in the generic syntax, but can also be used with the custom syntax on
gpu.funcs. The special kind of function for GPU allows one to use additional
features such as memory attribution.

PiperOrigin-RevId: 285822272
2019-12-16 12:12:48 -08:00
Mahesh Ravishankar 652fc261d7 Expose a convenience function to add interface attributes to a function.
PiperOrigin-RevId: 285036647
2019-12-11 12:21:42 -08:00
Mahesh Ravishankar 4a62019eb8 Add lowering for module with gpu.kernel_module attribute.
The existing GPU to SPIR-V lowering created a spv.module for every
function with gpu.kernel attribute. A better approach is to lower the
module that the function lives in (which has the attribute
gpu.kernel_module) to a spv.module operation. This better captures the
host-device separation modeled by GPU dialect and simplifies the
lowering as well.

PiperOrigin-RevId: 284574688
2019-12-09 09:52:21 -08:00
Mahesh Ravishankar 4d61a79db4 Allow specification of the workgroup size for GPUToSPIRV lowering.
SPIR-V/Vulkan spec requires the workgroups size to be specified with
the spv.ExecutionMode operation. This was hard-wired to be set to a
particular value. It is now changed to be configurable by clients of
the pass or of the patterns that implement the lowering from GPU to
SPIRV.

PiperOrigin-RevId: 284017482
2019-12-05 11:31:57 -08:00
Mahesh Ravishankar f87b2fd41b NFC: Actually expose the implementation of createGPUToSPIRVLoweringPass.
A mismatch in the function declaration and function definition,
prevented the implementation of the createGPUToSPIRVLoweringPass from
being exposed.

PiperOrigin-RevId: 282419815
2019-11-25 13:19:53 -08:00
Mahesh Ravishankar bd485afda0 Introduce attributes that specify the final ABI for a spirv::ModuleOp.
To simplify the lowering into SPIR-V, while still respecting the ABI
requirements of SPIR-V/Vulkan, split the process into two
1) While lowering a function to SPIR-V (when the function is an entry
   point function), allow specifying attributes on arguments and
   function itself that describe the ABI of the function.
2) Add a pass that materializes the ABI described in the function.

Two attributes are needed.
1) Attribute on arguments of the entry point function that describe
   the descriptor_set, binding, storage class, etc, of the
   spv.globalVariable this argument will be replaced by
2) Attribute on function that specifies workgroup size, etc. (for now
   only workgroup size).

Add the pass -spirv-lower-abi-attrs to materialize the ABI described
by the attributes.

This change makes the SPIRVBasicTypeConverter class unnecessary and is
removed, further simplifying the SPIR-V lowering path.

PiperOrigin-RevId: 282387587
2019-11-25 11:19:56 -08:00
Mahesh Ravishankar a78bd84cf8 NFC: Refactor Dialect Conversion targeting SPIR-V.
Refactoring the conversion from StandardOps/GPU dialect to SPIR-V
dialect:
1) Move the SPIRVTypeConversion and SPIRVOpLowering class into SPIR-V
   dialect.
2) Add header files that expose functions to add patterns for the
   dialects to SPIR-V lowering, as well as a pass that does the
   dialect to SPIR-V lowering.
3) Make SPIRVOpLowering derive from OpLowering class.
PiperOrigin-RevId: 280486871
2019-11-14 12:34:54 -08:00
River Riddle d985c74883 NFC: Refactor block signature conversion to not erase the original arguments.
This refactors the implementation of block signature(type) conversion to not insert fake cast operations to perform the type conversion, but to instead create a new block containing the proper signature. This has the benefit of enabling the use of pre-computed analyses that rely on mapping values. It also leads to a much cleaner implementation overall. The major user facing change is that applySignatureConversion will now replace the entry block of the region, meaning that blocks generally shouldn't be cached over calls to applySignatureConversion.

PiperOrigin-RevId: 280226936
2019-11-13 10:27:53 -08:00
Mahesh Ravishankar 9d985141ef Make legality check in GPU->SPIR-V lowering of FuncOp kernel specific.
Existing check that sets FuncOp to be dynamically legal was just
checking that the types of the argument are SPIR-V compatible. Since
the current conversion from GPU to SPIR-V does not handle lowering
non-kernel functions, change the legality check to verify that the
FuncOp has the gpu.kernel attribute and has void(void) return type.

PiperOrigin-RevId: 280032782
2019-11-12 12:52:53 -08:00
Mahesh Ravishankar 104af84f4c Add Conversion to lower loop::ForOp to spirv::LoopOp.
loop::ForOp can be lowered to the structured control flow represented
by spirv::LoopOp by making the continue block of the spirv::LoopOp the
loop latch and the merge block the exit block. The resulting
spirv::LoopOp has a single back edge from the continue to header
block, and a single exit from header to merge.
PiperOrigin-RevId: 280015614
2019-11-12 11:33:27 -08:00
Christian Sigg b74af4aa5c Unify GPU op definition names with other dialects.
Rename GPU op names from gpu_Foo to GPU_FooOp.

PiperOrigin-RevId: 275882232
2019-10-21 11:10:56 -07:00
Mahesh Ravishankar 54a8473470 Makes spv.module generated by GPU->SPIRV conversion spec compliant
Makes the spv.module generated by the GPU to SPIR-V conversion SPIR-V
spec compliant (validated using spirv-val from Vulkan tools).

1) Separate out the VulkanLayoutUtils from
DecorateSPIRVCompositeTypeLayoutPass to make it reusable within the
Type converter in SPIR-V lowering infrastructure. This is used to
compute the layout of the !spv.struct used in global variable type
description.
2) Set the capabilities of the spv.module to Shader (needed for use of
Logical Memory Model, and the extensions to
SPV_KHR_storage_buffer_storage_class for use of Storage Buffer)

PiperOrigin-RevId: 275081486
2019-10-16 11:53:07 -07:00
Mahesh Ravishankar e2ed25bc43 Make SPIR-V lowering infrastructure follow Vulkan SPIR-V validation.
The lowering infrastructure needs to be enhanced to lower into a
spv.Module that is consistent with the SPIR-V spec. The following
changes are needed
1) The Vulkan/SPIR-V validation rules dictates entry functions to have
signature of void(void). This requires changes to the function
signature conversion infrastructure within the dialect conversion
framework. When an argument is dropped from the original function
signature, a function can be specified that when invoked will return
the value to use as a replacement for the argument from the original
function.
2) Some changes to the type converter to make the converted type
consistent with the Vulkan/SPIR-V validation rules,
   a) Add support for converting dynamically shaped tensors to
   spv.rtarray type.
   b) Make the global variable of type !spv.ptr<!spv.struct<...>>
3) Generate the entry point operation for the kernel functions and
automatically compute all the interface variables needed

PiperOrigin-RevId: 273784229
2019-10-09 11:25:58 -07:00
Alex Zinenko 90d65d32d6 Use named modules for gpu.launch_func
The kernel function called by gpu.launch_func is now placed into an isolated
nested module during the outlining stage to simplify separate compilation.
Until recently, modules did not have names and could not be referenced. This
limitation was circumvented by introducing a stub kernel at the same name at
the same nesting level as the module containing the actual kernel. This
relation is only effective in one direction: from actual kernel function to its
launch_func "caller".

Leverage the recently introduced symbol name attributes on modules to refer to
a specific nested module from `gpu.launch_func`. This removes the implicit
connection between the identically named stub and kernel functions. It also
enables support for `gpu.launch_func`s to call different kernels located in the
same module.

PiperOrigin-RevId: 273491891
2019-10-08 04:30:32 -07:00
Lei Zhang 113aadddf9 Update SPIR-V symbols and use GLSL450 instead of VulkanKHR
SPIR-V recently publishes v1.5, which brings a bunch of symbols
into core. So the suffix "KHR"/"EXT"/etc. is removed from the
symbols. We use a script to pull information from the spec
directly.

Also changed conversion and tests to use GLSL450 instead of
VulkanKHR memory model. GLSL450 is still the main memory model
supported by Vulkan shaders and it does not require extra
capability to enable.

PiperOrigin-RevId: 268992661
2019-09-13 15:26:32 -07:00
River Riddle f1b100c77b NFC: Finish replacing FunctionPassBase/ModulePassBase with OpPassBase.
These directives were temporary during the generalization of FunctionPass/ModulePass to OpPass.

PiperOrigin-RevId: 268970259
2019-09-13 13:34:27 -07:00
Lei Zhang 5593e005c6 Add folding rule and dialect materialization hook for spv.constant
This will allow us to use MLIR's folding infrastructure to deduplicate
SPIR-V constants.

This CL also changed isValidSPIRVType in SPIRVDialect to a static method.

PiperOrigin-RevId: 266984403
2019-09-03 12:09:58 -07:00
Mahesh Ravishankar 4ced99c085 Enhance GPU To SPIR-V conversion to support builtins and load/store ops.
To support a conversion of a simple load-compute-store kernel from GPU
dialect to SPIR-V dialect, the conversion of operations like
"gpu.block_dim", "gpu.thread_id" which allow threads to get the launch
conversion is needed. In SPIR-V these are specified as global
variables with builin attributes. This CL adds support to specify
builtin variables in SPIR-V conversion framework. This is used to
convert the relevant operations from GPU dialect to SPIR-V dialect.
Also add support for conversion of load/store operation in Standard
dialect to SPIR-V dialect.
To simplify the conversion add a method to build a spv.AccessChain
operation that automatically determines the return type based on the
base pointer type and the indices provided.

PiperOrigin-RevId: 265718525
2019-08-27 10:50:23 -07:00
Mahesh Ravishankar cc980aa416 Simplify the classes that support SPIR-V conversion.
Modify the Type converters to have a SPIRVBasicTypeConverter which
only handles conversion from standard types to SPIRV types. Rename
SPIRVEntryFnConverter to SPIRVTypeConverter. This contains the
SPIRVBasicTypeConverter within it.

Remove SPIRVFnLowering class and have separate utility methods to
lower a function as entry function or a non-entry function. The
current setup could end with diamond inheritence that is not very
friendly to use.  For example, you could define the following Op
conversion methods that lower from a dialect "Foo" which resuls in
diamond inheritance.

template<typename OpTy>
class FooDialect : public SPIRVOpLowering<OpTy> {...};
class FooFnLowering : public FooDialect, SPIRVFnLowering {...};

PiperOrigin-RevId: 263597101
2019-08-15 10:54:46 -07:00
River Riddle 41968fb475 NFC: Update usages of OwningRewritePatternList to pass by & instead of &&.
This will allow for reusing the same pattern list, which may be costly to continually reconstruct, on multiple invocations.

PiperOrigin-RevId: 262664599
2019-08-09 17:20:29 -07:00
River Riddle a0df3ebd15 NFC: Implement OwningRewritePatternList as a class instead of a using directive.
This allows for proper forward declaration, as opposed to leaking the internal implementation via a using directive. This also allows for all pattern building to go through 'insert' methods on the OwningRewritePatternList, replacing uses of 'push_back' and 'RewriteListBuilder'.

PiperOrigin-RevId: 261816316
2019-08-05 18:38:22 -07:00