[Mlir-commits] [mlir] Reimplementing target description concept using DLTI attribute (PR #92138)

[Mehdi Amini]

================
@@ -194,6 +194,162 @@ def DataLayoutSpecInterface : AttrInterface<"DataLayoutSpecInterface"> {
   }];
 }
 
+def TargetDeviceDescSpecInterface : AttrInterface<"TargetDeviceDescSpecInterface"> {
+  let cppNamespace = "::mlir";
+
+  let description = [{
+    Attribute interface describing a target device description specification.
+
+    A target device description specification is a list of device properties (key)
+    and their values for a specific device. The device is identified using "device_id"
+    (as a key and ui32 value) and "device_type" key which must have a string value.
+    Both "device_id" and "device_type" are mandatory keys. As an example, L1 cache
+    size could be a device property, and its value would be a device specific size.
+
+    A target device description specification is attached to a module as a module level
+    attribute.
+  }];
+
+  let methods = [
+    InterfaceMethod<
+      /*description=*/"Returns the list of layout entries.",
+      /*retTy=*/"::mlir::DataLayoutEntryListRef",
+      /*methodName=*/"getEntries",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the entry related to the given identifier, if "
+                      "present.",
+      /*retTy=*/"::mlir::DataLayoutEntryInterface",
+      /*methodName=*/"getSpecForIdentifier",
+      /*args=*/(ins "::mlir::StringAttr":$identifier),
+      /*methodBody=*/"",
+      /*defaultImplementation=*/[{
+        return ::mlir::detail::filterEntryForIdentifier($_attr.getEntries(),
+                                                        identifier);
+      }]
+    >,
+    InterfaceMethod<
+      /*description=*/"Checks that the entry is well-formed, reports errors "
+                      "at the provided location.",
+      /*retTy=*/"::mlir::LogicalResult",
+      /*methodName=*/"verifyEntry",
+      /*args=*/(ins "::mlir::Location":$loc),
+      /*methodBody=*/"",
+      /*defaultImplementation=*/[{ return ::mlir::success(); }]
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the device ID identifier.",
+      /*retTy=*/"::mlir::StringAttr",
+      /*methodName=*/"getDeviceIDIdentifier",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the device type identifier.",
+      /*retTy=*/"::mlir::StringAttr",
+      /*methodName=*/"getDeviceTypeIdentifier",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the L1 cache size identifier.",
+      /*retTy=*/"::mlir::StringAttr",
+      /*methodName=*/"getL1CacheSizeInBytesIdentifier",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the max vector op width identifier.",
+      /*retTy=*/"::mlir::StringAttr",
+      /*methodName=*/"getMaxVectorOpWidthIdentifier",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the entry related to Device ID. The function"
+                      "will crash if the entry is missing.",
+      /*retTy=*/"::mlir::DataLayoutEntryInterface",
+      /*methodName=*/"getSpecForDeviceID",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the entry related to the given identifier. "
+                      "The function will crash if the entry is missing.",
+      /*retTy=*/"::mlir::DataLayoutEntryInterface",
+      /*methodName=*/"getSpecForDeviceType",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the entry related to the given identifier, if "
+                      "present. Otherwise, return empty spec.",
+      /*retTy=*/"::mlir::DataLayoutEntryInterface",
+      /*methodName=*/"getSpecForMaxVectorOpWidth",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the entry related to the given identifier, if "
+                      "present. Otherwise, return empty spec.",
+      /*retTy=*/"::mlir::DataLayoutEntryInterface",
+      /*methodName=*/"getSpecForL1CacheSizeInBytes",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the entry related to the given identifier, if "
+                      "present.",
+      /*retTy=*/"uint32_t",
+      /*methodName=*/"getDeviceID",
+      /*args=*/(ins)
+    >,
+  ];
+
+  let extraClassDeclaration = [{
+    using DeviceID = uint32_t;
+  }];
+}
+
+def TargetSystemDescSpecInterface : AttrInterface<"TargetSystemDescSpecInterface"> {
+  let cppNamespace = "::mlir";
+
+  let description = [{
+    Attribute interface describing a target system description specification.
+
+    A target system description specification is a list of target device
+    specifications, with one device specification for a device in the system. As
+    such, a target system description specification allows specifying a heterogenous
+    system, with devices of different types (e.g., CPU, GPU, etc.)
+
+    The only requirement on a valid target system description specification is that
+    the "device_id" in every target device description specification needs to be
+    unique. This is because, ultimately, this "device_id" is used by the user to
+    query a value of a device property.
+  }];
+
+  let methods = [
+    InterfaceMethod<
+      /*description=*/"Returns the list of layout entries.",
+      /*retTy=*/"llvm::ArrayRef<::mlir::TargetDeviceDescSpecInterface>",
+      /*methodName=*/"getEntries",
+      /*args=*/(ins)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the device description spec for given device "
+                      "ID",
+      /*retTy=*/"std::optional<::mlir::TargetDeviceDescSpecInterface>",
+      /*methodName=*/"getDeviceDescForDeviceID",
+      /*args=*/(ins "int":$deviceID)
----------------
joker-eph wrote:

Why do we use "int" for deviceID? This seems a bit limiting for me.

What about rewriting this API so that the `TargetSystemDescSpecInterface` actually expose a dictionary-like API of key-value pair, where the keys can be StringAttr (and must be dialect-prefixed to avoid any collision).


https://github.com/llvm/llvm-project/pull/92138