Adds SEScope (Storage/Execution Scope) for use as new unit of planning in 'device' planning.

include/tvm/ir/attrs.h

@@ -489,7 +489,7 @@ struct AttrInitEntry {
   ~AttrInitEntry() DMLC_THROW_EXCEPTION {
     if (value_missing_) {
       std::ostringstream os;
-      os << type_key_ << ": Cannot find required field \'" << key_ << "\' during initialization."
+      os << type_key_ << ": Cannot find required field \'" << key_ << "\' during initialization. "
          << "If the key is defined check that its type matches the declared type.";
       throw AttrError(os.str());
     }
@@ -806,7 +806,7 @@ class AttrsNode : public BaseAttrsNode {
     ICHECK_EQ(args.size() % 2, 0);
     const int kLinearSearchBound = 16;
     int hit_count = 0;
-    // applies two stratgies to lookup
+    // applies two strategies to lookup
     if (args.size() < kLinearSearchBound) {
       // linear search.
       auto ffind = [&args](const char* key, runtime::TVMArgValue* val) {

include/tvm/target/compilation_config.h

@@ -0,0 +1,170 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * \file tvm/target/compilation_config.h
+ * \brief A helper class to collect all the targets in canonical form necessary for compilation.
+ * CAUTION: Preliminary, currently only used to support device planning, very likely to change.
+ */
+
+#ifndef TVM_TARGET_COMPILATION_CONFIG_H_
+#define TVM_TARGET_COMPILATION_CONFIG_H_
+
+#include <tvm/target/se_scope.h>
+
+namespace tvm {
+
+/*!
+ * \brief Gathers the \p Targets and distinguished \p SEScopes in canonical form needed to
+ * compile a Relay module. All centralizes any setup and validation logic needed to transition
+ * from configuration options conveyed implicitly (eg in \p PassContexts) or explicitly
+ * (eg a a list of \p Targets) to the configuration.
+ *
+ * CAUTION: This is subject to change as we rework compilation options in general. See
+ * https://github.com/apache/tvm-rfcs/blob/main/rfcs/0028-command-line-registry-composition.md.
+ * So far this class is only focussed on carrying just the configuration needed by PlanDevices,
+ * and removing target-munging code duplication and inconsistencies between the three major build
+ * flows for the VM (relay/backend/vm/compile.cc), Graph/AOT (relay/backend/build_module.cc) and
+ * Interpreter (relay/backend/interpreter.cc). Over time we expect more global compiler
+ * configuration (eg for executor and runtime config, for system memory pool configuration, etc)
+ * to migrate into this class, and instances thereof to be attached to \p IRModules using a
+ * well-known attribute.
+ */
+class CompilationConfigNode : public Object {
+ public:
+  /*!
+   * \brief The legacy targets map, mapping device type to \p Targets. Does not include any
+   * entry for the host target. Intended to give a unique \p Target for every \p DLDeviceType,
+   * though we want to get rid of that limitation.
+   *
+   * CAUTION: Since keys are \p Integers they are compared by object equality not integer
+   * value.
+   *
+   * TODO(mbs): Remove once codegen updated for new target conventions.
+   */
+  TargetMap legacy_target_map;
+
+  /*!
+   * \brief The host target. Used for 'scalar' data and code (such as shapes and shape
+   * functions) and residual Relay expressions and data (such as conditionals and ADTs).
+   */
+  Target host_target;
+
+  /*!
+   * \brief Vector of all available targets for primitive operators. May contain a \p Target
+   * for the same device type as for the \p host_target, however the \p host_target should
+   * be preferred for all host computations and data.
+   */
+  Array<Target> primitive_targets;
+
+  /*!
+   * \brief \p SEScope for primitive operators which are not otherwise constrained to a particular
+   * device.
+   */
+  SEScope default_primitive_se_scope = SEScope::FullyUnconstrained();
+
+  /*! \brief SEScope for the host. */
+  SEScope host_se_scope = SEScope::FullyUnconstrained();
+
+  /*!
+   * \brief If defined then compile and/or run in 'homogenous execution mode'. In this mode all
+   * primitives are compiled for this target only.
+   *
+   * This is to support legacy passes which have not been adapted to hetrogeneous execution and
+   * rely on an implicit global \p Target to be in scope.
+   *
+   * TODO(mbs): Remove once all passes are 'hetrogeneous aware'.
+   */
+  Target optional_homogeneous_target;
+
+  void VisitAttrs(AttrVisitor* v);
+
+  /*!
+   * \brief Returns a \p SEScope agreeing with \p se_scope on all its constrained fields, however:
+   * - If the target is null then it is filled in from the known available primitive targets by
+   *   matching on device type. Fails if no such target is known.
+   * - The returned object is unique for the field values w.r.t. all other \p SEScopes returned
+   *   by this method.
+   *
+   * We call the result the 'canonical' \p SEScope. Two canonical \p SEScopes are structurally
+   * equal if and only if they are pointer equal.
+   */
+  SEScope CanonicalSEScope(const SEScope& se_scope) const;
+
+  static constexpr const char* _type_key = "CompilationConfig";
+  TVM_DECLARE_FINAL_OBJECT_INFO(CompilationConfigNode, Object)
+
+ private:
+  /*!
+   * \brief Establishes the default \p SEScope for primitives and the \p SEScope for the host
+   * given:
+   *  - the vector of available primitive \p Targets.
+   *  - any host \p Target.
+   *  - any "relay.fallback_device_type" attribute on \p pass_ctx.
+   *  - whether the LLVM backend is available.
+   * If necessary, creates new default \p Targets to match the required devices.
+   *
+   * NOTE: The implementation is a bit convoluted since it tries to maintain backwards
+   * compatibility with legacy methods for conveying \p Targets.
+   *
+   * CAUTION: Recreated the primitive_targets so that they all have the given/constructed
+   * host_target as their host (cf CheckAndUpdateHostConsistency).
+   */
+  void EstablishDefaultSEScopes(const transform::PassContext& pass_ctx);
+
+  /*!
+   * \brief Returns a freshly constructed \p Target to represent \p device_type.
+   */
+  static Target MakeDefaultTarget(DLDeviceType device_type);
+
+  /*!
+   * \brief Return the \p Target to use for \p device_type. Fail if no such target exists.
+   */
+  Target FindPrimitiveTargetOrFail(DLDeviceType device_type) const;
+
+  /*!
+   * \brief A cache of constructed SEScopes.
+   */
+  mutable SEScopeCache se_scope_cache_;
+
+  friend class CompilationConfig;
+};
+
+/*!
+ * \brief Managed reference class to \p CompilationConfig
+ *
+ * \sa CompilationConfig
+ */
+class CompilationConfig : public ObjectRef {
+ public:
+  /*!
+   * \brief Constructs the compilation config given the available \p Targets in the
+   * \p legacy_target_map_arg and an optional \p optional_host_target_arg. May use
+   * 'relay.fallback_device_type' and the availability of the LLVM compilation module
+   * to decide on appropriate default devices.
+   */
+  TVM_DLL CompilationConfig(const transform::PassContext& pass_ctx, TargetMap legacy_target_map_arg,
+                            Target optional_host_target_arg);
+
+  TVM_DEFINE_OBJECT_REF_METHODS(CompilationConfig, ObjectRef, CompilationConfigNode);
+};
+
+}  // namespace tvm
+
+#endif  // TVM_TARGET_COMPILATION_CONFIG_H_