[MLIR][LLVMIR][DLTI] Add LLVM::TargetAttrInterface and #llvm.target attr

mlir/include/mlir/CMakeLists.txt

@@ -4,4 +4,5 @@ add_subdirectory(Dialect)
 add_subdirectory(IR)
 add_subdirectory(Interfaces)
 add_subdirectory(Reducer)
+add_subdirectory(Target)
 add_subdirectory(Transforms)

mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td

@@ -13,6 +13,7 @@ include "mlir/Dialect/LLVMIR/LLVMDialect.td"
 include "mlir/Dialect/LLVMIR/LLVMInterfaces.td"
 include "mlir/IR/AttrTypeBase.td"
 include "mlir/IR/CommonAttrConstraints.td"
+include "mlir/Interfaces/DataLayoutInterfaces.td"
 
 // All of the attributes will extend this class.
 class LLVM_Attr<string name, string attrMnemonic,
@@ -1304,6 +1305,34 @@ def LLVM_TargetFeaturesAttr : LLVM_Attr<"TargetFeatures", "target_features">
   let genVerifyDecl = 1;
 }
 
+//===----------------------------------------------------------------------===//
+// LLVM_TargetAttr
+//===----------------------------------------------------------------------===//
+
+def LLVM_TargetAttr : LLVM_Attr<"Target", "target",
+                                [LLVM_TargetAttrInterface]> {
+  let summary = "LLVM target info: triple, chip, features";
+  let description = [{
+    An attribute to hold LLVM target information, specifying LLVM's target
+    `triple` string, the target `chip` string (i.e. the `cpu` string), and
+    target `features` string as an attribute. The latter is optional.
+
+    Responds to DLTI-queries on the keys:
+      * A query for `"triple"` returns the `StringAttr` for the `triple`.
+      * A query for `"chip"` returns the `StringAttr` for the `chip`/`cpu`.
+      * A query for `"features"` returns the `StringAttr`, if provided.
+  }];
+  let parameters = (ins "StringAttr":$triple,
+                        "StringAttr":$chip,
+                        OptionalParameter<"StringAttr", "">:$features);
+
+  let assemblyFormat = [{`<` struct($triple, $chip, $features) `>`}];
+
+  let extraClassDeclaration = [{
+    FailureOr<Attribute> query(DataLayoutEntryKey key);
+  }];
+}
+
 //===----------------------------------------------------------------------===//
 // UndefAttr
 //===----------------------------------------------------------------------===//

mlir/include/mlir/Dialect/LLVMIR/LLVMAttrs.h

@@ -16,6 +16,7 @@
 
 #include "mlir/Dialect/LLVMIR/LLVMTypes.h"
 #include "mlir/IR/OpImplementation.h"
+#include "mlir/Interfaces/DataLayoutInterfaces.h"
 #include <optional>
 
 #include "mlir/Dialect/LLVMIR/LLVMOpsEnums.h.inc"
@@ -89,8 +90,8 @@ class TBAANodeAttr : public Attribute {
 // TODO: this shouldn't be needed after we unify the attribute generation, i.e.
 // --gen-attr-* and --gen-attrdef-*.
 using cconv::CConv;
-using tailcallkind::TailCallKind;
 using linkage::Linkage;
+using tailcallkind::TailCallKind;
 } // namespace LLVM
 } // namespace mlir
 

mlir/include/mlir/Dialect/LLVMIR/LLVMDialect.td

@@ -27,6 +27,7 @@ def LLVM_Dialect : Dialect {
   );
 
   let extraClassDeclaration = [{
+    static StringRef getTargetAttrName() { return "llvm.target"; }
     /// Name of the data layout attributes.
     static StringRef getDataLayoutAttrName() { return "llvm.data_layout"; }
     static StringRef getNoAliasScopesAttrName() { return "noalias_scopes"; }

mlir/include/mlir/Dialect/LLVMIR/LLVMInterfaces.td

@@ -14,6 +14,7 @@
 #define LLVMIR_INTERFACES
 
 include "mlir/IR/OpBase.td"
+include "mlir/Interfaces/DataLayoutInterfaces.td"
 
 def FastmathFlagsInterface : OpInterface<"FastmathFlagsInterface"> {
   let description = [{
@@ -532,4 +533,39 @@ def LLVM_DIRecursiveTypeAttrInterface
   ];
 }
 
+def LLVM_TargetAttrInterface
+  : AttrInterface<"TargetAttrInterface", [DLTIQueryInterface]> {
+  let description = [{
+    Interface for attributes that describe LLVM targets.
+
+    These attributes should be able to return the specified target `triple`,
+    `chip` and `features`.
+
+    Implementing attributes should provide a `DLTIQueryInterface::query()`
+    implementation which responds to keys `"triple"`, `"chip"` and `"features"`
+    by returning appropriate `StringAttr`s.
+  }];
+  let cppNamespace = "::mlir::LLVM";
+  let methods = [
+    InterfaceMethod<
+      /*description=*/"Returns the target triple identifier.",
+      /*retTy=*/"StringAttr",
+      /*methodName=*/"getTriple",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the target chip (i.e. \"cpu\") identifier.",
+      /*retTy=*/"StringAttr",
+      /*methodName=*/"getChip",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the target features as a string.",
+      /*retTy=*/"StringAttr",
+      /*methodName=*/"getFeatures",
+      /*args=*/(ins)
+    >
+  ];
+}
+
 #endif // LLVMIR_INTERFACES

mlir/include/mlir/Target/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(LLVMIR)

mlir/include/mlir/Target/LLVMIR/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(Transforms)

mlir/lib/Target/LLVMIR/DataLayoutImporter.h → mlir/include/mlir/Target/LLVMIR/DataLayoutImporter.h

@@ -11,8 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef MLIR_LIB_TARGET_LLVMIR_DATALAYOUTIMPORTER_H_
-#define MLIR_LIB_TARGET_LLVMIR_DATALAYOUTIMPORTER_H_
+#ifndef MLIR_TARGET_LLVMIR_DATALAYOUTIMPORTER_H
+#define MLIR_TARGET_LLVMIR_DATALAYOUTIMPORTER_H
 
 #include "mlir/Dialect/LLVMIR/LLVMTypes.h"
 #include "mlir/IR/BuiltinAttributes.h"
@@ -38,23 +38,31 @@ namespace detail {
 /// null if the bit width is not supported.
 FloatType getFloatType(MLIRContext *context, unsigned width);
 
-/// Helper class that translates an LLVM data layout to an MLIR data layout
-/// specification. Only integer, float, pointer, alloca memory space, stack
-/// alignment, and endianness entries are translated. The class also returns all
-/// entries from the default data layout specification found in the language
-/// reference (https://llvm.org/docs/LangRef.html#data-layout) if they are not
-/// overwritten by the provided data layout.
+/// Helper class that translates an LLVM data layout string to an MLIR data
+/// layout specification. Only integer, float, pointer, alloca memory space,
+/// stack alignment, and endianness entries are translated. The class also
+/// returns all entries from the default data layout specification found in the
+/// language reference (https://llvm.org/docs/LangRef.html#data-layout) if they
+/// are not overwritten by the provided data layout.
 class DataLayoutImporter {
 public:
-  DataLayoutImporter(MLIRContext *context,
-                     const llvm::DataLayout &llvmDataLayout)
-      : context(context) {
-    translateDataLayout(llvmDataLayout);
+  DataLayoutImporter(MLIRContext *context, StringRef dataLayoutStr)
+      : dataLayoutStr(dataLayoutStr), context(context) {
+    // Translate the `dataLayoutStr`. First, append the default data layout
+    // string specified in the language reference
+    // (https://llvm.org/docs/LangRef.html#data-layout) to the supplied string.
+    // The translation then parses the string and ignores the default value if a
+    // specific kind occurs in both strings. Additionally, the following default
+    // values exist:
+    // - non-default address space pointer specifications default to the default
+    //   address space pointer specification
+    // - the alloca address space defaults to the default address space.
+    dataLayoutSpec = dataLayoutSpecFromDataLayoutStr();
   }
 
   /// Returns the MLIR data layout specification translated from the LLVM
   /// data layout.
-  DataLayoutSpecInterface getDataLayout() const { return dataLayout; }
+  DataLayoutSpecInterface getDataLayoutSpec() const { return dataLayoutSpec; }
 
   /// Returns the last data layout token that has been processed before
   /// the data layout translation failed.
@@ -65,8 +73,9 @@ class DataLayoutImporter {
   ArrayRef<StringRef> getUnhandledTokens() const { return unhandledTokens; }
 
 private:
-  /// Translates the LLVM `dataLayout` to an MLIR data layout specification.
-  void translateDataLayout(const llvm::DataLayout &llvmDataLayout);
+  /// Translate the LLVM data layout string to an MLIR data layout
+  /// specification.
+  DataLayoutSpecInterface dataLayoutSpecFromDataLayoutStr();
 
   /// Tries to parse the letter only prefix that identifies the specification
   /// and removes the consumed characters from the beginning of the string.
@@ -116,17 +125,18 @@ class DataLayoutImporter {
   /// Adds legal int widths entry if there is none yet.
   LogicalResult tryToEmplaceLegalIntWidthsEntry(StringRef token);
 
-  std::string layoutStr = {};
+  std::string dataLayoutStr = {};
+  DataLayoutSpecInterface dataLayoutSpec;
+
   StringRef lastToken = {};
   SmallVector<StringRef> unhandledTokens;
   llvm::MapVector<StringAttr, DataLayoutEntryInterface> keyEntries;
   llvm::MapVector<TypeAttr, DataLayoutEntryInterface> typeEntries;
   MLIRContext *context;
-  DataLayoutSpecInterface dataLayout;
 };
 
 } // namespace detail
 } // namespace LLVM
 } // namespace mlir
 
-#endif // MLIR_LIB_TARGET_LLVMIR_DATALAYOUTIMPORTER_H_
+#endif // MLIR_TARGET_LLVMIR_DATALAYOUTIMPORTER_H

mlir/include/mlir/Target/LLVMIR/Transforms/CMakeLists.txt

@@ -0,0 +1,5 @@
+set(LLVM_TARGET_DEFINITIONS Passes.td)
+mlir_tablegen(Passes.h.inc -gen-pass-decls -name TargetLLVMIRTransforms)
+add_public_tablegen_target(MLIRTargetLLVMIRTransformsIncGen)
+
+add_mlir_doc(Passes TargetLLVMIRTransforms ./ -gen-pass-doc)

mlir/include/mlir/Target/LLVMIR/Transforms/Passes.h

@@ -0,0 +1,27 @@
+//===- Passes.h - LLVM Target Pass Construction and Registration ----------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_TARGET_LLVMIR_TRANSFORMS_PASSES_H
+#define MLIR_TARGET_LLVMIR_TRANSFORMS_PASSES_H
+
+#include "mlir/Pass/Pass.h"
+
+namespace mlir {
+
+namespace LLVM {
+
+#define GEN_PASS_DECL
+#define GEN_PASS_REGISTRATION
+#include "mlir/Target/LLVMIR/Transforms/Passes.h.inc"
+
+void registerTargetLLVMPasses();
+
+} // namespace LLVM
+} // namespace mlir
+
+#endif // MLIR_TARGET_LLVMIR_TRANSFORMS_PASSES_H

mlir/include/mlir/Target/LLVMIR/Transforms/Passes.td

@@ -0,0 +1,30 @@
+//===-- Passes.td - LLVM Target pass definition file -------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_TARGET_LLVMIR_TRANSFORMS_PASSES
+#define MLIR_TARGET_LLVMIR_TRANSFORMS_PASSES
+
+include "mlir/Pass/PassBase.td"
+
+def LLVMTargetToDataLayout : Pass<"llvm-target-to-data-layout"> {
+  let summary = "Derive data layout attributes from LLVM target attributes";
+  let dependentDialects = ["mlir::DLTIDialect"];
+  let description = [{
+    Derive a `DataLayoutSpecInterface`-implementing data layout attribute from
+    the LLVM-backend target specified by the `TargetAttrInterface`-implementing
+    attribute attached to the target op at the name `llvm.target`.
+  }];
+  let options = [
+    Option<"initializeLLVMTargets", "initialize-llvm-targets", "bool",
+           /*default=*/"true",
+           "Whether to pre-load all available target machines, that LLVM is "
+           "configured to support, into the TargetRegistry.">
+  ];
+}
+
+#endif // MLIR_TARGET_LLVMIR_TRANSFORMS_PASSES

mlir/lib/Dialect/DLTI/Traits.cpp

@@ -24,7 +24,7 @@ LogicalResult mlir::impl::verifyHasDefaultDLTIDataLayoutTrait(Operation *op) {
 }
 
 DataLayoutSpecInterface mlir::impl::getDataLayoutSpec(Operation *op) {
-  return op->getAttrOfType<DataLayoutSpecAttr>(
+  return op->getAttrOfType<DataLayoutSpecInterface>(
       DLTIDialect::kDataLayoutAttrName);
 }
 

mlir/lib/Dialect/LLVMIR/IR/LLVMAttrs.cpp

@@ -402,3 +402,20 @@ ModuleFlagAttr::verify(function_ref<InFlightDiagnostic()> emitError,
                         "supported for unknown key '"
                      << key << "'";
 }
+
+//===----------------------------------------------------------------------===//
+// LLVM_TargetAttr
+//===----------------------------------------------------------------------===//
+
+FailureOr<::mlir::Attribute> TargetAttr::query(DataLayoutEntryKey key) {
+  if (auto stringAttrKey = dyn_cast<StringAttr>(key)) {
+    if (stringAttrKey.getValue() == "triple")
+      return getTriple();
+    if (stringAttrKey.getValue() == "chip")
+      return getChip();
+    if (stringAttrKey.getValue() == "features" && getFeatures())
+      return getFeatures();
+  }
+
+  return failure();
+}

mlir/lib/RegisterAllPasses.cpp

@@ -45,6 +45,7 @@
 #include "mlir/Dialect/Transform/Transforms/Passes.h"
 #include "mlir/Dialect/Vector/Transforms/Passes.h"
 #include "mlir/Dialect/XeGPU/Transforms/Passes.h"
+#include "mlir/Target/LLVMIR/Transforms/Passes.h"
 #include "mlir/Transforms/Passes.h"
 
 // This function may be called to register the MLIR passes with the
@@ -74,6 +75,7 @@ void mlir::registerAllPasses() {
   registerNVGPUPasses();
   registerSparseTensorPasses();
   LLVM::registerLLVMPasses();
+  LLVM::registerTargetLLVMIRTransformsPasses();
   math::registerMathPasses();
   memref::registerMemRefPasses();
   shard::registerShardPasses();

mlir/lib/Target/LLVMIR/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_subdirectory(Dialect)
+add_subdirectory(Transforms)
 
 set(LLVM_OPTIONAL_SOURCES
   ConvertFromLLVMIR.cpp