[mlir][IR][NFC] Define the Location classes in ODS instead of C++

[rriddle]

Summary

This also removes the need for LocationDetail.h.

mlir/include/mlir/IR/BuiltinLocationAttributes.td

+//===- BuiltinLocationAttributes.td - Builtin Locations ----*- 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 the set of builtin MLIR location attributes.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BUILTIN_LOCATION_ATTRIBUTES_TD
+#define BUILTIN_LOCATION_ATTRIBUTES_TD
+
+include "mlir/IR/BuiltinDialect.td"
+
+// Base class for Builtin dialect location attributes.
+class Builtin_LocationAttr<string name>
+    : AttrDef<Builtin_Dialect, name, "::mlir::LocationAttr"> {
+  let cppClassName = name;
+  let mnemonic = ?;
+}
+
+//===----------------------------------------------------------------------===//
+// CallSiteLoc
+//===----------------------------------------------------------------------===//
+
+def CallSiteLoc : Builtin_LocationAttr<"CallSiteLoc"> {
+  let summary = "A callsite source location";
+  let description = [{
+    Syntax:
+
+    ```
+    callsite-location ::= `callsite` `(` location `at` location `)`
+    ```
+
+    An instance of this location allows for representing a directed stack of
+    location usages. This connects a location of a `callee` with the location
+    of a `caller`.
+
+    Example:
+
+    ```mlir
+    loc(callsite("foo" at "mysource.cc":10:8))
+    ```
+  }];
+  let parameters = (ins "Location":$callee, "Location":$caller);
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "Location":$callee,
+                                        "Location":$caller), [{
+      return $_get(callee->getContext(), callee, caller);
+    }]>,
+    AttrBuilderWithInferredContext<(ins "Location":$name,
+                                        "ArrayRef<Location>":$frames)>
+  ];
+  let skipDefaultBuilders = 1;
+}
+
+//===----------------------------------------------------------------------===//
+// FileLineColLoc
+//===----------------------------------------------------------------------===//
+
+def FileLineColLoc : Builtin_LocationAttr<"FileLineColLoc"> {
+  let summary = "A file:line:column source location";
+  let description = [{
+    Syntax:
+
+    ```
+    filelinecol-location ::= string-literal `:` integer-literal `:`
+                             integer-literal
+    ```
+
+    An instance of this location represents a tuple of file, line number, and
+    column number. This is similar to the type of location that you get from
+    most source languages.
+
+    Example:
+
+    ```mlir
+    loc("mysource.cc":10:8)
+    ```
+  }];
+  let parameters = (ins "Identifier":$filename, "unsigned":$line,
+                        "unsigned":$column);
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "Identifier":$filename,
+                                        "unsigned":$line,
+                                        "unsigned":$column), [{
+      return $_get(filename.getContext(), filename, line, column);
+    }]>,
+    AttrBuilder<(ins "StringRef":$filename, "unsigned":$line,
+                     "unsigned":$column), [{
+      return $_get($_ctxt,
+                   Identifier::get(filename.empty() ? "-" : filename, $_ctxt),
+                   line, column);
+    }]>
+  ];
+  let skipDefaultBuilders = 1;
+}
+
+//===----------------------------------------------------------------------===//
+// FusedLoc
+//===----------------------------------------------------------------------===//
+
+def FusedLoc : Builtin_LocationAttr<"FusedLoc"> {
+  let summary = "A tuple of other source locations";
+  let description = [{
+    Syntax:
+
+    ```
+    fused-location ::= `fused` fusion-metadata? `[` location (location `,`)* `]`
+    fusion-metadata ::= `<` attribute-value `>`
+    ```
+
+    An instance of a `fused` location represents a grouping of several other
+    source locations, with optional metadata that describes the context of the
+    fusion. There are many places within a compiler in which several constructs
+    may be fused together, e.g. pattern rewriting, that normally result partial
+    or even total loss of location information. With `fused` locations, this is
+    a non-issue.
+
+    Example:
+
+    ```mlir
+    loc(fused["mysource.cc":10:8, "mysource.cc":22:8)
+    loc(fused<"CSE">["mysource.cc":10:8, "mysource.cc":22:8])
+    ```
+  }];
+  let parameters = (ins ArrayRefParameter<"Location", "">:$locations,
+                        "Attribute":$metadata);
+  let extraClassDeclaration = [{
+    static Location get(ArrayRef<Location> locs, Attribute metadata,
+                        MLIRContext *context);
+    static Location get(MLIRContext *context, ArrayRef<Location> locs) {
+      return get(locs, Attribute(), context);
+    }
+  }];
+}
+
+//===----------------------------------------------------------------------===//
+// NameLoc
+//===----------------------------------------------------------------------===//
+
+def NameLoc : Builtin_LocationAttr<"NameLoc"> {
+  let summary = "A named source location";
+  let description = [{
+    Syntax:
+
+    ```
+    name-location ::= string-literal (`(` location `)`)?
+    ```
+
+    An instance of this location allows for attaching a name to a child location.
+    This can be useful for representing the locations of variable, or node,
+    definitions.
+
+    Example:
+
+    ```mlir
+    loc("CSE"("mysource.cc":10:8))
+    ```
+  }];
+  let parameters = (ins "Identifier":$name, "Location":$childLoc);
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "Identifier":$name,
+                                        "Location":$childLoc), [{
+      return $_get(name.getContext(), name, childLoc);
+    }]>,
+    AttrBuilderWithInferredContext<(ins "Identifier":$name), [{
+      return $_get(name.getContext(), name,
+                   UnknownLoc::get(name.getContext()));
+    }]>
+  ];
+  let skipDefaultBuilders = 1;
+}
+
+//===----------------------------------------------------------------------===//
+// OpaqueLoc
+//===----------------------------------------------------------------------===//
+
+def OpaqueLoc : Builtin_LocationAttr<"OpaqueLoc"> {
+  let summary = "An opaque source location";
+  let description = [{
+    An instance of this location essentially contains a pointer to some data
+    structure that is external to MLIR and an optional location that can be used
+    if the first one is not suitable. Since it contains an external structure,
+    only the optional location is used during serialization.
+  }];
+  let parameters = (ins "uintptr_t":$underlyingLocation,
+                        "TypeID":$underlyingTypeID,
+                        "Location":$fallbackLocation);
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "uintptr_t":$underlyingLocation,
+                                        "TypeID":$underlyingTypeID,
+                                        "Location":$fallbackLocation), [{
+      return $_get(fallbackLocation->getContext(), underlyingLocation,
+                   underlyingTypeID, fallbackLocation);
+    }]>
+  ];
+  let extraClassDeclaration = [{
+    /// Returns an instance of opaque location which contains a given pointer to
+    /// an object. The corresponding MLIR location is set to UnknownLoc.
+    template <typename T>
+    static Location get(T underlyingLocation, MLIRContext *context);
+
+    /// Returns an instance of opaque location which contains a given pointer to
+    /// an object and an additional MLIR location.
+    template <typename T>
+    static Location get(T underlyingLocation, Location fallbackLocation) {
+      return get(reinterpret_cast<uintptr_t>(underlyingLocation),
+                 TypeID::get<T>(), fallbackLocation);
+    }
+
+    /// Returns a pointer to some data structure that opaque location stores.
+    template <typename T> static T getUnderlyingLocation(Location location) {
+      assert(isa<T>(location));
+      return reinterpret_cast<T>(
+          location.cast<mlir::OpaqueLoc>().getUnderlyingLocation());
+    }
+
+    /// Returns a pointer to some data structure that opaque location stores.
+    /// Returns nullptr if provided location is not opaque location or if it
+    /// contains a pointer of different type.
+    template <typename T>
+    static T getUnderlyingLocationOrNull(Location location) {
+      return isa<T>(location)
+                 ? reinterpret_cast<T>(
+                       location.cast<mlir::OpaqueLoc>().getUnderlyingLocation())
+                 : T(nullptr);
+    }
+
+    /// Checks whether provided location is opaque location and contains a
+    /// pointer to an object of particular type.
+    template <typename T> static bool isa(Location location) {
+      auto opaque_loc = location.dyn_cast<OpaqueLoc>();
+      return opaque_loc && opaque_loc.getUnderlyingTypeID() == TypeID::get<T>();
+    }
+  }];
+  let skipDefaultBuilders = 1;
+}
+
+//===----------------------------------------------------------------------===//
+// UnknownLoc
+//===----------------------------------------------------------------------===//
+
+def UnknownLoc : Builtin_LocationAttr<"UnknownLoc"> {
+  let summary = "An unspecified source location";
+  let description = [{
+    Syntax:
+
+    ```
+    unknown-location ::= `?`
+    ```
+
+    Source location information is an extremely integral part of the MLIR
+    infrastructure. As such, location information is always present in the IR,
+    and must explicitly be set to unknown. Thus, an instance of the `unknown`
+    location represents an unspecified source location.
+
+    Example:
+
+    ```mlir
+    loc(?)
+    ```
+  }];
+  let extraClassDeclaration = [{
+    static UnknownLoc get(MLIRContext *context);
+  }];
+}
+
+#endif // BUILTIN_LOCATION_ATTRIBUTES_TD

mlir/include/mlir/IR/CMakeLists.txt

 add_mlir_interface(OpAsmInterface)
 add_mlir_interface(SymbolInterfaces)
 add_mlir_interface(RegionKindInterface)
 
 set(LLVM_TARGET_DEFINITIONS BuiltinAttributes.td)
 mlir_tablegen(BuiltinAttributes.h.inc -gen-attrdef-decls)
 mlir_tablegen(BuiltinAttributes.cpp.inc -gen-attrdef-defs)
 add_public_tablegen_target(MLIRBuiltinAttributesIncGen)
 
 set(LLVM_TARGET_DEFINITIONS BuiltinDialect.td)
 mlir_tablegen(BuiltinDialect.h.inc -gen-dialect-decls)
 add_public_tablegen_target(MLIRBuiltinDialectIncGen)
 
+set(LLVM_TARGET_DEFINITIONS BuiltinLocationAttributes.td)
+mlir_tablegen(BuiltinLocationAttributes.h.inc -gen-attrdef-decls)
+mlir_tablegen(BuiltinLocationAttributes.cpp.inc -gen-attrdef-defs)
+add_public_tablegen_target(MLIRBuiltinLocationAttributesIncGen)
+
 set(LLVM_TARGET_DEFINITIONS BuiltinOps.td)
 mlir_tablegen(BuiltinOps.h.inc -gen-op-decls)
 mlir_tablegen(BuiltinOps.cpp.inc -gen-op-defs)
 add_public_tablegen_target(MLIRBuiltinOpsIncGen)
 
 set(LLVM_TARGET_DEFINITIONS BuiltinTypes.td)
 mlir_tablegen(BuiltinTypes.h.inc -gen-typedef-decls)
 mlir_tablegen(BuiltinTypes.cpp.inc -gen-typedef-defs)
 add_public_tablegen_target(MLIRBuiltinTypesIncGen)
 
 add_mlir_doc(BuiltinOps -gen-op-doc Builtin Dialects/)

mlir/include/mlir/IR/Location.h

 #ifndef MLIR_IR_LOCATION_H
 #define MLIR_IR_LOCATION_H
 
 #include "mlir/IR/Attributes.h"
 #include "llvm/Support/PointerLikeTypeTraits.h"
 
 namespace mlir {
 
-class Attribute;
-class MLIRContext;
 class Identifier;
 
-namespace detail {
-
-struct CallSiteLocationStorage;
-struct FileLineColLocationStorage;
-struct FusedLocationStorage;
-struct LocationStorage;
-struct NameLocationStorage;
-struct OpaqueLocationStorage;
-struct UnknownLocationStorage;
-
-} // namespace detail
+//===----------------------------------------------------------------------===//
+// LocationAttr
+//===----------------------------------------------------------------------===//
 
 /// Location objects represent source locations information in MLIR.
 /// LocationAttr acts as the anchor for all Location based attributes.
 class LocationAttr : public Attribute {
 public:
   using Attribute::Attribute;
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast.
   static bool classof(Attribute attr);
 };
 
+//===----------------------------------------------------------------------===//
+// Location
+//===----------------------------------------------------------------------===//
+
 /// This class defines the main interface for locations in MLIR and acts as a
 /// non-nullable wrapper around a LocationAttr.
 class Location {
 public:
   Location(LocationAttr loc) : impl(loc) {
     assert(loc && "location should never be null.");
   }
   Location(const LocationAttr::ImplType *impl) : impl(impl) {
protected:
   LocationAttr impl;
 };
 
 inline raw_ostream &operator<<(raw_ostream &os, const Location &loc) {
   loc.print(os);
   return os;
 }
 
-/// Represents a location as call site. "callee" is the concrete location
-/// (Unknown/NameLocation/FileLineColLoc/OpaqueLoc) and "caller" points to the
-/// caller's location (another CallLocation or a concrete location). Multiple
-/// CallSiteLocs can be chained to form a call stack.
-class CallSiteLoc
-    : public Attribute::AttrBase<CallSiteLoc, LocationAttr,
-                                 detail::CallSiteLocationStorage> {
-public:
-  using Base::Base;
-
-  /// Return a uniqued call location object.
-  static Location get(Location callee, Location caller);
-
-  /// Return a call site location which represents a name reference in one line
-  /// or a stack of frames. The input frames are ordered from innermost to
-  /// outermost.
-  static Location get(Location name, ArrayRef<Location> frames);
-
-  /// The concrete location information this object presents.
-  Location getCallee() const;
-
-  /// The caller's location.
-  Location getCaller() const;
-};
-
-/// Represents a location derived from a file/line/column location.  The column
-/// and line may be zero to represent unknown column and/or unknown line/column
-/// information.
-class FileLineColLoc
-    : public Attribute::AttrBase<FileLineColLoc, LocationAttr,
-                                 detail::FileLineColLocationStorage> {
-public:
-  using Base::Base;
-
-  /// Return a uniqued FileLineCol location object.
-  static Location get(Identifier filename, unsigned line, unsigned column);
-  static Location get(StringRef filename, unsigned line, unsigned column,
-                      MLIRContext *context);
-
-  StringRef getFilename() const;
-
-  unsigned getLine() const;
-  unsigned getColumn() const;
-};
-
-/// Represents a value composed of multiple source constructs, with an optional
-/// metadata attribute.
-class FusedLoc : public Attribute::AttrBase<FusedLoc, LocationAttr,
-                                            detail::FusedLocationStorage> {
-public:
-  using Base::Base;
-
-  /// Return a uniqued Fused Location object. The first location in the list
-  /// will get precedence during diagnostic emission, with the rest being
-  /// displayed as supplementary "fused from here" style notes.
-  static Location get(ArrayRef<Location> locs, Attribute metadata,
-                      MLIRContext *context);
-  static Location get(ArrayRef<Location> locs, MLIRContext *context) {
-    return get(locs, Attribute(), context);
-  }
-
-  ArrayRef<Location> getLocations() const;
-
-  /// Returns the optional metadata attached to this fused location. Given that
-  /// it is optional, the return value may be a null node.
-  Attribute getMetadata() const;
-};
-
-/// Represents an identity name attached to a child location.
-class NameLoc : public Attribute::AttrBase<NameLoc, LocationAttr,
-                                           detail::NameLocationStorage> {
-public:
-  using Base::Base;
-
-  /// Return a uniqued name location object. The child location must not be
-  /// another NameLoc.
-  static Location get(Identifier name, Location child);
-
-  /// Return a uniqued name location object with an unknown child.
-  static Location get(Identifier name);
+// Make Location hashable.
+inline ::llvm::hash_code hash_value(Location arg) {
+  return hash_value(arg.impl);
+}
 
-  /// Return the name identifier.
-  Identifier getName() const;
+} // end namespace mlir
 
-  /// Return the child location.
-  Location getChildLoc() const;
-};
+//===----------------------------------------------------------------------===//
+// Tablegen Attribute Declarations
+//===----------------------------------------------------------------------===//
 
-/// Represents an unknown location.  This is always a singleton for a given
-/// MLIRContext.
-class UnknownLoc
-    : public Attribute::AttrBase<UnknownLoc, LocationAttr, AttributeStorage> {
-public:
-  using Base::Base;
+#define GET_ATTRDEF_CLASSES
+#include "mlir/IR/BuiltinLocationAttributes.h.inc"
 
-  /// Get an instance of the UnknownLoc.
-  static Location get(MLIRContext *context);
-};
+namespace mlir {
 
-/// Represents a location that is external to MLIR. Contains a pointer to some
-/// data structure and an optional location that can be used if the first one is
-/// not suitable. Since it contains an external structure, only optional
-/// location is used during serialization.
-/// The class also provides a number of methods for making type-safe casts
-/// between a pointer to an object and opaque location.
-class OpaqueLoc : public Attribute::AttrBase<OpaqueLoc, LocationAttr,
-                                             detail::OpaqueLocationStorage> {
-public:
-  using Base::Base;
+//===----------------------------------------------------------------------===//
+// OpaqueLoc
+//===----------------------------------------------------------------------===//
 
-  /// Returns an instance of opaque location which contains a given pointer to
-  /// an object. The corresponding MLIR location is set to UnknownLoc.
-  template <typename T>
-  static Location get(T underlyingLocation, MLIRContext *context) {
-    return get(reinterpret_cast<uintptr_t>(underlyingLocation),
-               TypeID::get<T>(), UnknownLoc::get(context));
-  }
-
-  /// Returns an instance of opaque location which contains a given pointer to
-  /// an object and an additional MLIR location.
-  template <typename T>
-  static Location get(T underlyingLocation, Location fallbackLocation) {
-    return get(reinterpret_cast<uintptr_t>(underlyingLocation),
-               TypeID::get<T>(), fallbackLocation);
-  }
-
-  /// Returns a pointer to some data structure that opaque location stores.
-  template <typename T> static T getUnderlyingLocation(Location location) {
-    assert(isa<T>(location));
-    return reinterpret_cast<T>(
-        location.cast<mlir::OpaqueLoc>().getUnderlyingLocation());
-  }
-
-  /// Returns a pointer to some data structure that opaque location stores.
-  /// Returns nullptr if provided location is not opaque location or if it
-  /// contains a pointer of different type.
-  template <typename T>
-  static T getUnderlyingLocationOrNull(Location location) {
-    return isa<T>(location)
-               ? reinterpret_cast<T>(
-                     location.cast<mlir::OpaqueLoc>().getUnderlyingLocation())
-               : T(nullptr);
-  }
-
-  /// Checks whether provided location is opaque location and contains a pointer
-  /// to an object of particular type.
-  template <typename T> static bool isa(Location location) {
-    auto opaque_loc = location.dyn_cast<OpaqueLoc>();
-    return opaque_loc && opaque_loc.getUnderlyingTypeID() == TypeID::get<T>();
-  }
-
-  /// Returns a pointer to the corresponding object.
-  uintptr_t getUnderlyingLocation() const;
-
-  /// Returns a TypeID that represents the underlying objects c++ type.
-  TypeID getUnderlyingTypeID() const;
-
-  /// Returns a fallback location.
-  Location getFallbackLocation() const;
-
-private:
-  static Location get(uintptr_t underlyingLocation, TypeID typeID,
-                      Location fallbackLocation);
-};
-
-// Make Location hashable.
-inline ::llvm::hash_code hash_value(Location arg) {
-  return hash_value(arg.impl);
+inline Location OpaqueLoc::get(T underlyingLocation, MLIRContext *context) {
+  return get(reinterpret_cast<uintptr_t>(underlyingLocation), TypeID::get<T>(),
+             UnknownLoc::get(context));
 }
+} // namespace mlir
 
-} // end namespace mlir
+//===----------------------------------------------------------------------===//
+// LLVM Utilities
+//===----------------------------------------------------------------------===//
 
 namespace llvm {
 
 // Type hash just like pointers.
 template <> struct DenseMapInfo<mlir::Location> {
   static mlir::Location getEmptyKey() {
     auto pointer = llvm::DenseMapInfo<void *>::getEmptyKey();
     return mlir::Location::getFromOpaquePointer(pointer);

mlir/lib/CAPI/IR/IR.cpp

 
 //===----------------------------------------------------------------------===//
 // Location API.
 //===----------------------------------------------------------------------===//
 
 MlirLocation mlirLocationFileLineColGet(MlirContext context,
                                         MlirStringRef filename, unsigned line,
                                         unsigned col) {
-  return wrap(
-      FileLineColLoc::get(unwrap(filename), line, col, unwrap(context)));
+  return wrap(Location(
+      FileLineColLoc::get(unwrap(context), unwrap(filename), line, col)));
 }
 
 MlirLocation mlirLocationCallSiteGet(MlirLocation callee, MlirLocation caller) {
-  return wrap(CallSiteLoc::get(unwrap(callee), unwrap(caller)));
+  return wrap(Location(CallSiteLoc::get(unwrap(callee), unwrap(caller))));
 }
 
 MlirLocation mlirLocationUnknownGet(MlirContext context) {
-  return wrap(UnknownLoc::get(unwrap(context)));
+  return wrap(Location(UnknownLoc::get(unwrap(context))));
 }
 
 bool mlirLocationEqual(MlirLocation l1, MlirLocation l2) {
   return unwrap(l1) == unwrap(l2);
 }
 
 MlirContext mlirLocationGetContext(MlirLocation location) {
   return wrap(unwrap(location).getContext());

mlir/lib/Dialect/Quant/Transforms/ConvertConst.cpp

QuantizedConstRewrite::matchAndRewrite(QuantizeCastOp qbarrier,
   auto newConstValue =
       quantizeAttr(value, quantizedElementType, newConstValueType);
   if (!newConstValue) {
     return failure();
   }
 
   // When creating the new const op, use a fused location that combines the
   // original const and the qbarrier that led to the quantization.
-  auto fusedLoc = FusedLoc::get(
-      {qbarrier.arg().getDefiningOp()->getLoc(), qbarrier.getLoc()},
-      rewriter.getContext());
+  auto fusedLoc = rewriter.getFusedLoc(
+      {qbarrier.arg().getDefiningOp()->getLoc(), qbarrier.getLoc()});
   auto newConstOp =
       rewriter.create<ConstantOp>(fusedLoc, newConstValueType, newConstValue);
   rewriter.replaceOpWithNewOp<StorageCastOp>(qbarrier, qbarrier.getType(),
                                              newConstOp);
   return success();
 }
 
 void ConvertConstPass::runOnFunction() {

mlir/lib/IR/CMakeLists.txt

add_mlir_library(MLIRIR
   Visitors.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/IR
 
   DEPENDS
   MLIRBuiltinAttributesIncGen
   MLIRBuiltinDialectIncGen
+  MLIRBuiltinLocationAttributesIncGen
   MLIRBuiltinOpsIncGen
   MLIRBuiltinTypesIncGen
   MLIRCallInterfacesIncGen
   MLIRCastInterfacesIncGen
   MLIROpAsmInterfaceIncGen
   MLIRRegionKindInterfaceIncGen
   MLIRSideEffectInterfacesIncGen
   MLIRSymbolInterfacesIncGen
 
   LINK_LIBS PUBLIC
   MLIRSupport
   )

mlir/lib/IR/Location.cpp

 //===- Location.cpp - MLIR Location Classes -------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "mlir/IR/Location.h"
-#include "LocationDetail.h"
+#include "mlir/IR/Identifier.h"
 #include "llvm/ADT/SetVector.h"
 
 using namespace mlir;
 using namespace mlir::detail;
 
 //===----------------------------------------------------------------------===//
+/// Tablegen Attribute Definitions
+//===----------------------------------------------------------------------===//
+
+#define GET_ATTRDEF_CLASSES
+#include "mlir/IR/BuiltinLocationAttributes.cpp.inc"
+
+//===----------------------------------------------------------------------===//
 // LocationAttr
 //===----------------------------------------------------------------------===//
 
 /// Methods for support type inquiry through isa, cast, and dyn_cast.
 bool LocationAttr::classof(Attribute attr) {
   return attr.isa<CallSiteLoc, FileLineColLoc, FusedLoc, NameLoc, OpaqueLoc,
                   UnknownLoc>();
 }
 
 //===----------------------------------------------------------------------===//
 // CallSiteLoc
 //===----------------------------------------------------------------------===//
 
-Location CallSiteLoc::get(Location callee, Location caller) {
-  return Base::get(callee->getContext(), callee, caller);
-}
-
-Location CallSiteLoc::get(Location name, ArrayRef<Location> frames) {
+CallSiteLoc CallSiteLoc::get(Location name, ArrayRef<Location> frames) {
   assert(!frames.empty() && "required at least 1 call frame");
   Location caller = frames.back();
   for (auto frame : llvm::reverse(frames.drop_back()))
     caller = CallSiteLoc::get(frame, caller);
   return CallSiteLoc::get(name, caller);
 }
 
-Location CallSiteLoc::getCallee() const { return getImpl()->callee; }
-
-Location CallSiteLoc::getCaller() const { return getImpl()->caller; }
-
-//===----------------------------------------------------------------------===//
-// FileLineColLoc
-//===----------------------------------------------------------------------===//
-
-Location FileLineColLoc::get(Identifier filename, unsigned line,
-                             unsigned column) {
-  return Base::get(filename.getContext(), filename, line, column);
-}
-
-Location FileLineColLoc::get(StringRef filename, unsigned line, unsigned column,
-                             MLIRContext *context) {
-  return get(Identifier::get(filename.empty() ? "-" : filename, context), line,
-             column);
-}
-
-StringRef FileLineColLoc::getFilename() const { return getImpl()->filename; }
-unsigned FileLineColLoc::getLine() const { return getImpl()->line; }
-unsigned FileLineColLoc::getColumn() const { return getImpl()->column; }
-
 //===----------------------------------------------------------------------===//
 // FusedLoc
 //===----------------------------------------------------------------------===//
 
 Location FusedLoc::get(ArrayRef<Location> locs, Attribute metadata,
                        MLIRContext *context) {
   // Unique the set of locations to be fused.
   llvm::SmallSetVector<Location, 4> decomposedLocs;
Location FusedLoc::get(ArrayRef<Location> locs, Attribute metadata,
 
   // Handle the simple cases of less than two locations.
   if (locs.empty())
     return UnknownLoc::get(context);
   if (locs.size() == 1)
     return locs.front();
   return Base::get(context, locs, metadata);
 }
-
-ArrayRef<Location> FusedLoc::getLocations() const {
-  return getImpl()->getLocations();
-}
-
-Attribute FusedLoc::getMetadata() const { return getImpl()->metadata; }
-
-//===----------------------------------------------------------------------===//
-// NameLoc
-//===----------------------------------------------------------------------===//
-
-Location NameLoc::get(Identifier name, Location child) {
-  assert(!child.isa<NameLoc>() &&
-         "a NameLoc cannot be used as a child of another NameLoc");
-  return Base::get(child->getContext(), name, child);
-}
-
-Location NameLoc::get(Identifier name) {
-  return get(name, UnknownLoc::get(name.getContext()));
-}
-
-/// Return the name identifier.
-Identifier NameLoc::getName() const { return getImpl()->name; }
-
-/// Return the child location.
-Location NameLoc::getChildLoc() const { return getImpl()->child; }
-
-//===----------------------------------------------------------------------===//
-// OpaqueLoc
-//===----------------------------------------------------------------------===//
-
-Location OpaqueLoc::get(uintptr_t underlyingLocation, TypeID typeID,
-                        Location fallbackLocation) {
-  return Base::get(fallbackLocation->getContext(), underlyingLocation, typeID,
-                   fallbackLocation);
-}
-
-uintptr_t OpaqueLoc::getUnderlyingLocation() const {
-  return Base::getImpl()->underlyingLocation;
-}
-
-TypeID OpaqueLoc::getUnderlyingTypeID() const { return getImpl()->typeID; }
-
-Location OpaqueLoc::getFallbackLocation() const {
-  return Base::getImpl()->fallbackLocation;
-}

mlir/lib/IR/LocationDetail.h

-//===- LocationDetail.h - MLIR Location storage details ---------*- 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 holds implementation details of the location attributes.
-//
-//===----------------------------------------------------------------------===//
-#ifndef MLIR_IR_LOCATIONDETAIL_H_
-#define MLIR_IR_LOCATIONDETAIL_H_
-
-#include "mlir/IR/Attributes.h"
-#include "mlir/IR/Identifier.h"
-#include "mlir/IR/Location.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/Support/TrailingObjects.h"
-
-namespace mlir {
-
-namespace detail {
-
-struct CallSiteLocationStorage : public AttributeStorage {
-  CallSiteLocationStorage(Location callee, Location caller)
-      : callee(callee), caller(caller) {}
-
-  /// The hash key used for uniquing.
-  using KeyTy = std::pair<Location, Location>;
-  bool operator==(const KeyTy &key) const {
-    return key == KeyTy(callee, caller);
-  }
-
-  /// Construct a new storage instance.
-  static CallSiteLocationStorage *
-  construct(AttributeStorageAllocator &allocator, const KeyTy &key) {
-    return new (allocator.allocate<CallSiteLocationStorage>())
-        CallSiteLocationStorage(key.first, key.second);
-  }
-
-  Location callee, caller;
-};
-
-struct FileLineColLocationStorage : public AttributeStorage {
-  FileLineColLocationStorage(Identifier filename, unsigned line,
-                             unsigned column)
-      : filename(filename), line(line), column(column) {}
-
-  /// The hash key used for uniquing.
-  using KeyTy = std::tuple<Identifier, unsigned, unsigned>;
-  bool operator==(const KeyTy &key) const {
-    return key == KeyTy(filename, line, column);
-  }
-
-  /// Construct a new storage instance.
-  static FileLineColLocationStorage *
-  construct(AttributeStorageAllocator &allocator, const KeyTy &key) {
-    return new (allocator.allocate<FileLineColLocationStorage>())
-        FileLineColLocationStorage(std::get<0>(key), std::get<1>(key),
-                                   std::get<2>(key));
-  }
-
-  Identifier filename;
-  unsigned line, column;
-};
-
-struct FusedLocationStorage final
-    : public AttributeStorage,
-      public llvm::TrailingObjects<FusedLocationStorage, Location> {
-  FusedLocationStorage(unsigned numLocs, Attribute metadata)
-      : numLocs(numLocs), metadata(metadata) {}
-
-  ArrayRef<Location> getLocations() const {
-    return ArrayRef<Location>(getTrailingObjects<Location>(), numLocs);
-  }
-
-  /// The hash key used for uniquing.
-  using KeyTy = std::pair<ArrayRef<Location>, Attribute>;
-  bool operator==(const KeyTy &key) const {
-    return key == KeyTy(getLocations(), metadata);
-  }
-
-  /// Construct a new storage instance.
-  static FusedLocationStorage *construct(AttributeStorageAllocator &allocator,
-                                         const KeyTy &key) {
-    ArrayRef<Location> locs = key.first;
-
-    auto byteSize = totalSizeToAlloc<Location>(locs.size());
-    auto rawMem = allocator.allocate(byteSize, alignof(FusedLocationStorage));
-    auto result = new (rawMem) FusedLocationStorage(locs.size(), key.second);
-
-    std::uninitialized_copy(locs.begin(), locs.end(),
-                            result->getTrailingObjects<Location>());
-    return result;
-  }
-
-  // This stuff is used by the TrailingObjects template.
-  friend llvm::TrailingObjects<FusedLocationStorage, Location>;
-  size_t numTrailingObjects(OverloadToken<Location>) const { return numLocs; }
-
-  /// Number of trailing location objects.
-  unsigned numLocs;
-
-  /// Metadata used to reason about the generation of this fused location.
-  Attribute metadata;
-};
-
-struct NameLocationStorage : public AttributeStorage {
-  NameLocationStorage(Identifier name, Location child)
-      : name(name), child(child) {}
-
-  /// The hash key used for uniquing.
-  using KeyTy = std::pair<Identifier, Location>;
-  bool operator==(const KeyTy &key) const { return key == KeyTy(name, child); }
-
-  /// Construct a new storage instance.
-  static NameLocationStorage *construct(AttributeStorageAllocator &allocator,
-                                        const KeyTy &key) {
-    return new (allocator.allocate<NameLocationStorage>())
-        NameLocationStorage(key.first, key.second);
-  }
-
-  Identifier name;
-  Location child;
-};
-
-struct OpaqueLocationStorage : public AttributeStorage {
-  OpaqueLocationStorage(uintptr_t underlyingLocation, TypeID typeID,
-                        Location fallbackLocation)
-      : underlyingLocation(underlyingLocation), typeID(typeID),
-        fallbackLocation(fallbackLocation) {}
-
-  /// The hash key used for uniquing.
-  using KeyTy = std::tuple<uintptr_t, TypeID, Location>;
-  bool operator==(const KeyTy &key) const {
-    return key == KeyTy(underlyingLocation, typeID, fallbackLocation);
-  }
-
-  /// Construct a new storage instance.
-  static OpaqueLocationStorage *construct(AttributeStorageAllocator &allocator,
-                                          const KeyTy &key) {
-    return new (allocator.allocate<OpaqueLocationStorage>())
-        OpaqueLocationStorage(std::get<0>(key), std::get<1>(key),
-                              std::get<2>(key));
-  }
-
-  /// Pointer to the corresponding object.
-  uintptr_t underlyingLocation;
-
-  /// A unique pointer for each type of underlyingLocation.
-  TypeID typeID;
-
-  /// An additional location that can be used if the external one is not
-  /// suitable.
-  Location fallbackLocation;
-};
-
-} // end namespace detail
-} // end namespace mlir
-
-#endif // MLIR_IR_LOCATIONDETAIL_H_

mlir/lib/IR/MLIRContext.cpp

 //===- MLIRContext.cpp - MLIR Type Classes --------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "mlir/IR/MLIRContext.h"
 #include "AffineExprDetail.h"
 #include "AffineMapDetail.h"
 #include "AttributeDetail.h"
 #include "IntegerSetDetail.h"
-#include "LocationDetail.h"
 #include "TypeDetail.h"
 #include "mlir/IR/AffineExpr.h"
 #include "mlir/IR/AffineMap.h"
 #include "mlir/IR/Attributes.h"
 #include "mlir/IR/BuiltinDialect.h"
 #include "mlir/IR/Diagnostics.h"
 #include "mlir/IR/Dialect.h"
 #include "mlir/IR/Identifier.h"

 BoolAttr BoolAttr::get(MLIRContext *context, bool value) {
   return value ? context->getImpl().trueAttr : context->getImpl().falseAttr;
 }
 
 UnitAttr UnitAttr::get(MLIRContext *context) {
   return context->getImpl().unitAttr;
 }
 
-Location UnknownLoc::get(MLIRContext *context) {
+UnknownLoc UnknownLoc::get(MLIRContext *context) {
   return context->getImpl().unknownLocAttr;
 }
 
 /// Return empty dictionary.
 DictionaryAttr DictionaryAttr::getEmpty(MLIRContext *context) {
   return context->getImpl().emptyDictionaryAttr;
 }
 

mlir/lib/Parser/Lexer.cpp

 /// Encode the specified source location information into an attribute for
 /// attachment to the IR.
 Location Lexer::getEncodedSourceLocation(llvm::SMLoc loc) {
   auto &sourceMgr = getSourceMgr();
   unsigned mainFileID = sourceMgr.getMainFileID();
   auto lineAndColumn = sourceMgr.getLineAndColumn(loc, mainFileID);
   auto *buffer = sourceMgr.getMemoryBuffer(mainFileID);
 
-  return FileLineColLoc::get(buffer->getBufferIdentifier(), lineAndColumn.first,
-                             lineAndColumn.second, context);
+  return FileLineColLoc::get(context, buffer->getBufferIdentifier(),
+                             lineAndColumn.first, lineAndColumn.second);
 }
 
 /// emitError - Emit an error message and return an Token::error token.
 Token Lexer::emitError(const char *loc, const Twine &message) {
   mlir::emitError(getEncodedSourceLocation(SMLoc::getFromPointer(loc)),
                   message);
   return formToken(Token::error, loc);
 }

mlir/lib/Parser/LocationParser.cpp

if (consumeIf(Token::colon)) {
     // Parse the column number.
     if (getToken().isNot(Token::integer))
       return emitError("expected integer column number in FileLineColLoc");
     auto column = getToken().getUnsignedIntegerValue();
     if (!column.hasValue())
       return emitError("expected integer column number in FileLineColLoc");
     consumeToken(Token::integer);
 
-    loc = FileLineColLoc::get(str, line.getValue(), column.getValue(), ctx);
+    loc = FileLineColLoc::get(ctx, str, line.getValue(), column.getValue());
     return success();
   }
 
   // Otherwise, this is a NameLoc.
 
   // Check for a child location.
   if (consumeIf(Token::l_paren)) {
     auto childSourceLoc = getToken().getLoc();

mlir/lib/Parser/Parser.cpp

 
 //===----------------------------------------------------------------------===//
 
 LogicalResult mlir::parseSourceFile(const llvm::SourceMgr &sourceMgr,
                                     Block *block, MLIRContext *context,
                                     LocationAttr *sourceFileLoc) {
   const auto *sourceBuf = sourceMgr.getMemoryBuffer(sourceMgr.getMainFileID());
 
-  Location parserLoc = FileLineColLoc::get(sourceBuf->getBufferIdentifier(),
-                                           /*line=*/0, /*column=*/0, context);
+  Location parserLoc = FileLineColLoc::get(
+      context, sourceBuf->getBufferIdentifier(), /*line=*/0, /*column=*/0);
   if (sourceFileLoc)
     *sourceFileLoc = parserLoc;
 
   SymbolState aliasState;
   ParserState state(sourceMgr, context, aliasState);
   return TopLevelOperationParser(state).parse(block, parserLoc);
 }
 

mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp

 }
 
 // Handles importing globals and functions from an LLVM module.
 namespace {
 class Importer {
 public:
   Importer(MLIRContext *context, ModuleOp module)
       : b(context), context(context), module(module),
-        unknownLoc(FileLineColLoc::get("imported-bitcode", 0, 0, context)),
+        unknownLoc(FileLineColLoc::get(context, "imported-bitcode", 0, 0)),
         typeTranslator(*context) {
     b.setInsertionPointToStart(module.getBody());
   }
 
   /// Imports `f` into the current module.
   LogicalResult processFunction(llvm::Function *f);
 
   /// Imports GV as a GlobalOp, creating it if it doesn't exist.

 
 Location Importer::processDebugLoc(const llvm::DebugLoc &loc,
                                    llvm::Instruction *inst) {
   if (!loc && inst) {
     std::string s;
     llvm::raw_string_ostream os(s);
     os << "llvm-imported-inst-%";
     inst->printAsOperand(os, /*PrintType=*/false);
-    return FileLineColLoc::get(os.str(), 0, 0, context);
+    return FileLineColLoc::get(context, os.str(), 0, 0);
   } else if (!loc) {
     return unknownLoc;
   }
   // FIXME: Obtain the filename from DILocationInfo.
-  return FileLineColLoc::get("imported-bitcode", loc.getLine(), loc.getCol(),
-                             context);
+  return FileLineColLoc::get(context, "imported-bitcode", loc.getLine(),
+                             loc.getCol());
 }
 
 Type Importer::processType(llvm::Type *type) {
   if (Type result = typeTranslator.translateType(type))
     return result;
 
   // FIXME: Diagnostic should be able to natively handle types that have
   // operator<<(raw_ostream&) defined.
LogicalResult Importer::processBasicBlock(llvm::BasicBlock *bb, Block *block) {
   return success();
 }
 
 OwningModuleRef
 mlir::translateLLVMIRToModule(std::unique_ptr<llvm::Module> llvmModule,
                               MLIRContext *context) {
   context->loadDialect<LLVMDialect>();
   OwningModuleRef module(ModuleOp::create(
-      FileLineColLoc::get("", /*line=*/0, /*column=*/0, context)));
+      FileLineColLoc::get(context, "", /*line=*/0, /*column=*/0)));
 
   Importer deserializer(context, module.get());
   for (llvm::GlobalVariable &gv : llvmModule->globals()) {
     if (!deserializer.processGlobal(&gv))
       return {};
   }
   for (llvm::Function &f : llvmModule->functions()) {
     if (failed(deserializer.processFunction(&f)))

mlir/lib/Target/LLVMIR/DebugTranslation.cpp

const bool hasCallWithoutDebugInfo =
             return call.getLoc().isa<UnknownLoc>() ? WalkResult::interrupt()
                                                    : WalkResult::advance();
           })
           .wasInterrupted();
   if (hasCallWithoutDebugInfo)
     return;
 
   FileLineColLoc fileLoc = extractFileLoc(func.getLoc());
-  auto *file = translateFile(fileLoc ? fileLoc.getFilename() : "<unknown>");
+  auto *file =
+      translateFile(fileLoc ? fileLoc.getFilename().strref() : "<unknown>");
   unsigned line = fileLoc ? fileLoc.getLine() : 0;
 
   // TODO: This is the bare essentials for now. We will likely end
   // up with wrapper metadata around LLVMs metadata in the future, so this
   // doesn't need to be smart until then.
   llvm::DISubroutineType *type =
       builder.createSubroutineType(builder.getOrCreateTypeArray(llvm::None));
   llvm::DISubprogram::DISPFlags spFlags = llvm::DISubprogram::SPFlagDefinition |

mlir/lib/Target/SPIRV/Serialization/Serializer.cpp

for (auto cap : module.vce_triple()->getCapabilities())
     (void)encodeInstructionInto(capabilities, spirv::Opcode::OpCapability,
                                 {static_cast<uint32_t>(cap)});
 }
 
 void Serializer::processDebugInfo() {
   if (!emitDebugInfo)
     return;
   auto fileLoc = module.getLoc().dyn_cast<FileLineColLoc>();
-  auto fileName = fileLoc ? fileLoc.getFilename() : "<unknown>";
+  auto fileName = fileLoc ? fileLoc.getFilename().strref() : "<unknown>";
   fileID = getNextID();
   SmallVector<uint32_t, 16> operands;
   operands.push_back(fileID);
   (void)spirv::encodeStringLiteralInto(operands, fileName);
   (void)encodeInstructionInto(debug, spirv::Opcode::OpString, operands);
   // TODO: Encode more debug instructions.
 }
 

mlir/lib/Target/SPIRV/TranslateRegistration.cpp

static OwningModuleRef deserializeModule(const llvm::MemoryBuffer *input,
   auto binary = llvm::makeArrayRef(reinterpret_cast<const uint32_t *>(start),
                                    size / sizeof(uint32_t));
 
   spirv::OwningSPIRVModuleRef spirvModule = spirv::deserialize(binary, context);
   if (!spirvModule)
     return {};
 
   OwningModuleRef module(ModuleOp::create(FileLineColLoc::get(
-      input->getBufferIdentifier(), /*line=*/0, /*column=*/0, context)));
+      context, input->getBufferIdentifier(), /*line=*/0, /*column=*/0)));
   module->getBody()->push_front(spirvModule.release());
 
   return module;
 }
 
 namespace mlir {
 void registerFromSPIRVTranslation() {
   TranslateToMLIRRegistration fromBinary(
static LogicalResult roundTripModule(ModuleOp srcModule, bool emitDebugInfo,
   deserializationContext.loadAllAvailableDialects();
   // Then deserialize to get back a SPIR-V module.
   spirv::OwningSPIRVModuleRef spirvModule =
       spirv::deserialize(binary, &deserializationContext);
   if (!spirvModule)
     return failure();
 
   // Wrap around in a new MLIR module.
-  OwningModuleRef dstModule(ModuleOp::create(FileLineColLoc::get(
-      /*filename=*/"", /*line=*/0, /*column=*/0, &deserializationContext)));
+  OwningModuleRef dstModule(ModuleOp::create(
+      FileLineColLoc::get(&deserializationContext,
+                          /*filename=*/"", /*line=*/0, /*column=*/0)));
   dstModule->getBody()->push_front(spirvModule.release());
   dstModule->print(output);
 
   return mlir::success();
 }
 
 namespace mlir {
 void registerTestRoundtripSPIRV() {