[mlir] Add the TransformsInterfaces for configuring transformations

This patch adds the `ConversionPatternsAttrInterface` and
`OpWithTransformAttrsOpInterface` interfaces. It also modifies the
`convert-to-llvm` pass to use these interfaces when available.

The `ConversionPatternsAttrInterface` allows attributes to configure the dialect
conversion infrastructure, including the conversion target, type converter, and
populating conversion patterns. See the `NVVMTargetAttr` implementation of this
interface for an example of how this interface can be used to configure dialect
conversion.

The `OpWithTransformAttrsOpInterface` allows interacting with transforms
attributes. These attributes allow configuring transformations like dialect
conversion with information present in the IR.

Finally, the `convert-to-llvm` pass was modified to use these interfaces when
available. This allows applying `convert-to-llvm` to GPU modules and letting the
`NVVMTargetAttr` decide which patterns to populate.

Author: fabianmcg

mlir/include/mlir/Conversion/GPUToNVVM/GPUToNVVM.h

@@ -0,0 +1,26 @@
+//===- GPUToNVVM.h - Convert GPU to NVVM dialect ----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This files declares registration functions for converting GPU to NVVM.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_CONVERSION_GPUTONVVM_GPUTONVVM_H
+#define MLIR_CONVERSION_GPUTONVVM_GPUTONVVM_H
+
+namespace mlir {
+class DialectRegistry;
+namespace NVVM {
+/// Registers the `ConversionPatternsAttrInterface` interface on the
+/// `NVVM::NVVMTargetAttr`. This interface populates the conversion target,
+/// LLVM type converter, and pattern set for converting GPU operations to NVVM.
+void registerConvertGpuToNVVMAttrInterface(DialectRegistry &registry);
+} // namespace NVVM
+} // namespace mlir
+
+#endif // MLIR_CONVERSION_GPUTONVVM_GPUTONVVM_H

mlir/include/mlir/Conversion/GPUToNVVM/GPUToNVVMPass.h

@@ -31,6 +31,10 @@ LLVM::LLVMStructType convertMMAToLLVMType(gpu::MMAMatrixType type);
 /// Configure target to convert from the GPU dialect to NVVM.
 void configureGpuToNVVMConversionLegality(ConversionTarget &target);
 
+/// Configure the LLVM type convert to convert types and address spaces from the
+/// GPU dialect to NVVM.
+void configureGpuToNVVMTypeConverter(LLVMTypeConverter &converter);
+
 /// Collect a set of patterns to convert from the GPU dialect to NVVM.
 void populateGpuToNVVMConversionPatterns(LLVMTypeConverter &converter,
                                          RewritePatternSet &patterns);

mlir/include/mlir/Conversion/LLVMCommon/ConversionAttrOptions.h

@@ -0,0 +1,39 @@
+//===- ConversionAttrOptions.h - LLVM conversion options --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares convert to LLVM options for `ConversionPatternAttr`.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_CONVERSION_LLVMCOMMON_CONVERSIONATTROPTIONS_H
+#define MLIR_CONVERSION_LLVMCOMMON_CONVERSIONATTROPTIONS_H
+
+#include "mlir/Interfaces/TransformsInterfaces.h"
+
+namespace mlir {
+class LLVMTypeConverter;
+
+/// Class for passing convert to LLVM options to `ConversionPatternAttr`
+/// attributes.
+class LLVMConversionPatternAttrOptions : public ConversionPatternAttrOptions {
+public:
+  LLVMConversionPatternAttrOptions(ConversionTarget &target,
+                                   LLVMTypeConverter &converter);
+
+  static bool classof(ConversionPatternAttrOptions const *opts) {
+    return opts->getTypeID() == TypeID::get<LLVMConversionPatternAttrOptions>();
+  }
+
+  /// Get the LLVM type converter.
+  LLVMTypeConverter &getLLVMTypeConverter();
+};
+} // namespace mlir
+
+MLIR_DECLARE_EXPLICIT_TYPE_ID(::mlir::LLVMConversionPatternAttrOptions)
+
+#endif // MLIR_CONVERSION_LLVMCOMMON_CONVERSIONATTROPTIONS_H

mlir/include/mlir/Dialect/GPU/IR/GPUDialect.h

@@ -28,6 +28,7 @@
 #include "mlir/Interfaces/InferIntRangeInterface.h"
 #include "mlir/Interfaces/InferTypeOpInterface.h"
 #include "mlir/Interfaces/SideEffectInterfaces.h"
+#include "mlir/Interfaces/TransformsInterfaces.h"
 #include "llvm/ADT/STLExtras.h"
 
 namespace mlir {

mlir/include/mlir/Dialect/GPU/IR/GPUOps.td

@@ -29,6 +29,7 @@ include "mlir/Interfaces/FunctionInterfaces.td"
 include "mlir/Interfaces/InferIntRangeInterface.td"
 include "mlir/Interfaces/InferTypeOpInterface.td"
 include "mlir/Interfaces/SideEffectInterfaces.td"
+include "mlir/Interfaces/TransformsInterfaces.td"
 
 //===----------------------------------------------------------------------===//
 // GPU Dialect operations.
@@ -1347,7 +1348,8 @@ def GPU_BarrierOp : GPU_Op<"barrier"> {
 
 def GPU_GPUModuleOp : GPU_Op<"module", [
       DataLayoutOpInterface, HasDefaultDLTIDataLayout, IsolatedFromAbove,
-      SymbolTable, Symbol, SingleBlockImplicitTerminator<"ModuleEndOp">
+      DeclareOpInterfaceMethods<OpWithTransformAttrsOpInterface>, SymbolTable,
+      Symbol, SingleBlockImplicitTerminator<"ModuleEndOp">
     ]>, Arguments<(ins SymbolNameAttr:$sym_name,
           OptionalAttr<GPUNonEmptyTargetArrayAttr>:$targets,
           OptionalAttr<OffloadingTranslationAttr>:$offloadingHandler)> {

mlir/include/mlir/InitAllExtensions.h

@@ -18,6 +18,7 @@
 #include "mlir/Conversion/ComplexToLLVM/ComplexToLLVM.h"
 #include "mlir/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.h"
 #include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVM.h"
+#include "mlir/Conversion/GPUToNVVM/GPUToNVVM.h"
 #include "mlir/Conversion/IndexToLLVM/IndexToLLVM.h"
 #include "mlir/Conversion/MathToLLVM/MathToLLVM.h"
 #include "mlir/Conversion/MemRefToLLVM/MemRefToLLVM.h"
@@ -65,6 +66,7 @@ inline void registerAllExtensions(DialectRegistry &registry) {
   registerConvertMemRefToLLVMInterface(registry);
   registerConvertNVVMToLLVMInterface(registry);
   ub::registerConvertUBToLLVMInterface(registry);
+  NVVM::registerConvertGpuToNVVMAttrInterface(registry);
 
   // Register all transform dialect extensions.
   affine::registerTransformDialectExtension(registry);

mlir/include/mlir/Interfaces/CMakeLists.txt

@@ -36,6 +36,14 @@ mlir_tablegen(DataLayoutTypeInterface.cpp.inc -gen-type-interface-defs)
 add_public_tablegen_target(MLIRDataLayoutInterfacesIncGen)
 add_dependencies(mlir-generic-headers MLIRDataLayoutInterfacesIncGen)
 
+set(LLVM_TARGET_DEFINITIONS TransformsInterfaces.td)
+mlir_tablegen(TransformsAttrInterfaces.h.inc -gen-attr-interface-decls)
+mlir_tablegen(TransformsAttrInterfaces.cpp.inc -gen-attr-interface-defs)
+mlir_tablegen(TransformsOpInterfaces.h.inc -gen-op-interface-decls)
+mlir_tablegen(TransformsOpInterfaces.cpp.inc -gen-op-interface-defs)
+add_public_tablegen_target(MLIRTransformsInterfacesIncGen)
+add_dependencies(mlir-generic-headers MLIRTransformsInterfacesIncGen)
+
 add_mlir_doc(DataLayoutInterfaces
   DataLayoutAttrInterface
   Interfaces/

mlir/include/mlir/Interfaces/TransformsInterfaces.h

@@ -0,0 +1,71 @@
+//===- TransformsInterfaces.h - Transforms interfaces -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares interfaces for managing transformations, including
+// populating pattern rewrites.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_INTERFACES_TRANSFORMSINTERFACES_H
+#define MLIR_INTERFACES_TRANSFORMSINTERFACES_H
+
+#include "mlir/IR/OpDefinition.h"
+
+namespace mlir {
+class ConversionTarget;
+class RewritePatternSet;
+class TypeConverter;
+
+/// This class serves as an opaque interface for passing options to the
+/// `ConversionPatternsAttrInterface` methods. Users of this class must
+/// implement the `classof` method as well as using the macros
+/// `MLIR_*_EXPLICIT_TYPE_ID` toensure type safeness.
+class ConversionPatternAttrOptions {
+public:
+  ConversionPatternAttrOptions(ConversionTarget &target,
+                               TypeConverter &converter);
+
+  /// Returns the typeID.
+  TypeID getTypeID() const { return typeID; }
+
+  /// Returns a reference to the conversion target to configure.
+  ConversionTarget &getConversionTarget() { return target; }
+
+  /// Returns a reference to the type converter to configure.
+  TypeConverter &getTypeConverter() { return converter; }
+
+protected:
+  /// Derived classes must use this constructor to initialize `typeID` to the
+  /// appropiate value.
+  ConversionPatternAttrOptions(TypeID typeID, ConversionTarget &target,
+                               TypeConverter &converter);
+  // Conversion target.
+  ConversionTarget ⌖
+  // Type converter.
+  TypeConverter &converter;
+
+private:
+  TypeID typeID;
+};
+
+/// Helper function for populating dialect conversion patterns. If `op`
+/// implements the `OpWithTransformAttrsOpInterface` interface, then the
+/// conversion pattern attributes provided by the interface will be used to
+/// configure the conversion target, type converter, and the pattern set.
+void populateOpConversionPatterns(Operation *op,
+                                  ConversionPatternAttrOptions &options,
+                                  RewritePatternSet &patterns);
+} // namespace mlir
+
+#include "mlir/Interfaces/TransformsAttrInterfaces.h.inc"
+
+#include "mlir/Interfaces/TransformsOpInterfaces.h.inc"
+
+MLIR_DECLARE_EXPLICIT_TYPE_ID(::mlir::ConversionPatternAttrOptions)
+
+#endif // MLIR_INTERFACES_TRANSFORMSINTERFACES_H

mlir/include/mlir/Interfaces/TransformsInterfaces.td

@@ -0,0 +1,77 @@
+//===- TransformsInterfaces.td - Transforms interfaces -----*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines interfaces for managing transformations, including populating
+// pattern rewrites.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_INTERFACES_TRANSFORMSINTERFACES_TD
+#define MLIR_INTERFACES_TRANSFORMSINTERFACES_TD
+
+include "mlir/IR/OpBase.td"
+
+//===----------------------------------------------------------------------===//
+// Conversion patterns attribute interface
+//===----------------------------------------------------------------------===//
+
+def ConversionPatternsAttrInterface :
+    AttrInterface<"ConversionPatternsAttrInterface"> {
+  let description = [{
+    This interfaces allows using attributes to configure the dialect conversion
+    infrastructure, this includes:
+     - The conversion target.
+     - The type converter.
+     - The pattern set.
+    
+    The conversion target and type converter are passed through the
+    `ConversionPatternAttrOptions` class. Passing them through this class
+    and by reference allows sub-classing the base option class, allowing
+    specializations like `LLVMConversionPatternAttrOptions` for converting to
+    LLVM.
+  }];
+  let cppNamespace = "::mlir";
+  let methods = [
+    InterfaceMethod<
+      /*desc=*/[{
+        Populate the dialect conversion target, type converter and pattern set.
+      }],
+      /*retTy=*/"void",
+      /*methodName=*/"populateConversionPatterns",
+      /*args=*/(ins "::mlir::ConversionPatternAttrOptions&":$options,
+                    "::mlir::RewritePatternSet&":$patternSet)>
+  ];
+}
+
+//===----------------------------------------------------------------------===//
+// Operation with patterns interface
+//===----------------------------------------------------------------------===//
+
+def OpWithTransformAttrsOpInterface :
+    OpInterface<"OpWithTransformAttrsOpInterface"> {
+  let description = [{
+    Interface for interacting with transforms attributes. These attributes
+    allow configuring transformations like dialect conversion with information
+    present in the IR.
+  }];
+  let cppNamespace = "::mlir";
+  let methods = [
+    InterfaceMethod<
+      /*desc=*/[{
+        Populate the provided vector with a list of conversion pattern
+        attributes to apply.
+      }],
+      /*retTy=*/"void",
+      /*methodName=*/"getConversionPatternAttrs",
+      /*args=*/(ins
+        "::llvm::SmallVectorImpl<::mlir::ConversionPatternsAttrInterface>&":$attrs)
+    >
+  ];
+}
+
+#endif // MLIR_INTERFACES_TRANSFORMSINTERFACES_TD

mlir/lib/Conversion/ConvertToLLVM/ConvertToLLVMPass.cpp

@@ -8,10 +8,12 @@
 
 #include "mlir/Conversion/ConvertToLLVM/ToLLVMInterface.h"
 #include "mlir/Conversion/ConvertToLLVM/ToLLVMPass.h"
+#include "mlir/Conversion/LLVMCommon/ConversionAttrOptions.h"
 #include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
 #include "mlir/Conversion/LLVMCommon/TypeConverter.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/IR/PatternMatch.h"
+#include "mlir/Interfaces/TransformsInterfaces.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Rewrite/FrozenRewritePatternSet.h"
 #include "mlir/Transforms/DialectConversion.h"
@@ -61,9 +63,8 @@ class LoadDependentDialectExtension : public DialectExtensionBase {
 /// the injection of conversion patterns.
 class ConvertToLLVMPass
     : public impl::ConvertToLLVMPassBase<ConvertToLLVMPass> {
-  std::shared_ptr<const FrozenRewritePatternSet> patterns;
-  std::shared_ptr<const ConversionTarget> target;
-  std::shared_ptr<const LLVMTypeConverter> typeConverter;
+  std::shared_ptr<const SmallVector<ConvertToLLVMPatternInterface *>>
+      interfaces;
 
 public:
   using impl::ConvertToLLVMPassBase<ConvertToLLVMPass>::ConvertToLLVMPassBase;
@@ -73,11 +74,8 @@ class ConvertToLLVMPass
   }
 
   LogicalResult initialize(MLIRContext *context) final {
-    RewritePatternSet tempPatterns(context);
-    auto target = std::make_shared<ConversionTarget>(*context);
-    target->addLegalDialect<LLVM::LLVMDialect>();
-    auto typeConverter = std::make_shared<LLVMTypeConverter>(context);
-
+    auto interfaces =
+        std::make_shared<SmallVector<ConvertToLLVMPatternInterface *>>();
     if (!filterDialects.empty()) {
       // Test mode: Populate only patterns from the specified dialects. Produce
       // an error if the dialect is not loaded or does not implement the
@@ -92,8 +90,7 @@ class ConvertToLLVMPass
           return emitError(UnknownLoc::get(context))
                  << "dialect does not implement ConvertToLLVMPatternInterface: "
                  << dialectName << "\n";
-        iface->populateConvertToLLVMConversionPatterns(*target, *typeConverter,
-                                                       tempPatterns);
+        interfaces->push_back(iface);
       }
     } else {
       // Normal mode: Populate all patterns from all dialects that implement the
@@ -104,20 +101,33 @@ class ConvertToLLVMPass
         auto *iface = dyn_cast<ConvertToLLVMPatternInterface>(dialect);
         if (!iface)
           continue;
-        iface->populateConvertToLLVMConversionPatterns(*target, *typeConverter,
-                                                       tempPatterns);
+        interfaces->push_back(iface);
       }
     }
 
-    this->patterns =
-        std::make_unique<FrozenRewritePatternSet>(std::move(tempPatterns));
-    this->target = target;
-    this->typeConverter = typeConverter;
+    this->interfaces = interfaces;
     return success();
   }
 
   void runOnOperation() final {
-    if (failed(applyPartialConversion(getOperation(), *target, *patterns)))
+    MLIRContext *context = &getContext();
+    RewritePatternSet patterns(context);
+    ConversionTarget target(*context);
+    target.addLegalDialect<LLVM::LLVMDialect>();
+    LLVMTypeConverter typeConverter(context);
+
+    // Configure the conversion with dialect level interfaces.
+    for (ConvertToLLVMPatternInterface *iface : *interfaces)
+      iface->populateConvertToLLVMConversionPatterns(target, typeConverter,
+                                                     patterns);
+
+    // Configure the conversion attribute interfaces.
+    LLVMConversionPatternAttrOptions opts(target, typeConverter);
+    populateOpConversionPatterns(getOperation(), opts, patterns);
+
+    // Apply the conversion.
+    if (failed(applyPartialConversion(getOperation(), target,
+                                      std::move(patterns))))
       signalPassFailure();
   }
 };