[relay] Relay annotation and partitioning for codegen

include/tvm/relay/attrs/annotation.h

@@ -57,6 +57,19 @@ struct CastHintAttrs : public tvm::AttrsNode<CastHintAttrs> {
   }
 };
 
+/*!
+ * \brief Options for the operators used to annotate a compiler.
+ */
+struct CompilerAttrs : public tvm::AttrsNode<CompilerAttrs> {
+  /*! \brief The 3rd party compiler for code generation. */
+  std::string compiler;
+
+  TVM_DECLARE_ATTRS(CompilerAttrs, "relay.attrs.CompilerAttrs") {
+    TVM_ATTR_FIELD(compiler)
+      .describe("The 3rd compiler used for code generation.");
+  }
+};
+
 }  // namespace relay
 }  // namespace tvm
 #endif  // TVM_RELAY_ATTRS_ANNOTATION_H_

include/tvm/relay/op_attr_types.h

@@ -29,6 +29,7 @@
 #include <tvm/build_module.h>
 #include <tvm/relay/type.h>
 #include <tvm/relay/expr.h>
+#include <string>
 
 namespace tvm {
 namespace relay {
@@ -122,7 +123,7 @@ using FTVMSchedule = runtime::TypedPackedFunc<
  *  operator with other expressions. This function will be invoked
  *  in AlterOpLayout pass.
  * \param attrs The attribute of the original node.
- * \param inputs The input symbols of the original node.
+ * \param args The input symbols of the original node.
  * \param tinfos An array of placeholders, use for getting the inferred shape
  *               and dtype of the inputs.
  * \return new_expr The modified expression.
@@ -136,8 +137,8 @@ using FTVMAlterOpLayout = runtime::TypedPackedFunc<
  * \brief Legalizes an expression with another expression. This function will be
  *  invoked in Legalize pass. It is a target-dependent pass.
  * \param attrs The attribute of the original node.
- * \param inputs The input symbols of the original node.
- * \param tinfos An array of placeholders, use for getting the inferred shape
+ * \param args The input symbols of the original node.
+ * \param arg_types An array of placeholders, use for getting the inferred shape
  *               and dtype of the inputs.
  * \return new_expr The modified expression.
  */
@@ -146,6 +147,22 @@ using FTVMLegalize = runtime::TypedPackedFunc<
        const Array<Expr>& args,
        const Array<tvm::relay::Type>& arg_types)>;
 
+/*!
+ * \brief Annotates an expression to indicate which compiler an op
+ * should be used for codegen.
+ *
+ * \param attrs The attribute of the original expr.
+ * \param args The arguments of the original expr.
+ * \param compiler The compiler that is used to compile the op.
+ *
+ * \return true if this op should be registered to invoke a specific compiler
+ * for codegen, otherwise, false.
+ */
+using FTVMAnnotateCompiler = runtime::TypedPackedFunc<
+  bool(const Attrs& attrs,  // NOLINT(*)
+       const Array<Expr>& args,
+       const std::string& compiler)>;
+
 /*!
  * \brief Forward rewriting rule for a specific op.
  *

include/tvm/relay/transform.h

@@ -576,6 +576,14 @@ TVM_DLL Pass EtaExpand(bool expand_constructor, bool expand_global_var);
  */
 TVM_DLL Pass PrintIR(bool show_meta_data = true);
 
+/*!
+ * \brief Partition a Relay program into regions that can be executed on
+ * different backends.
+ *
+ * \return The pass.
+ */
+TVM_DLL Pass PartitionGraph();
+
 }  // namespace transform
 
 /*!

python/tvm/relay/__init__.py

@@ -29,7 +29,7 @@
 from . import adt
 from . import analysis
 from . import transform
-from .build_module import build, create_executor, optimize
+from .build_module import build, create_executor, optimize, build_extern_compiler
 from .transform import build_config
 from . import prelude
 from . import parser

python/tvm/relay/build_module.py

@@ -30,6 +30,7 @@
 from .module import Module as _Module
 from .backend import interpreter as _interpreter
 from .backend.vm import VMExecutor
+from . import transform as _transform
 
 def _update_target(target):
     target = target if target else _target.current_target()
@@ -296,6 +297,34 @@ def optimize(mod, target=None, params=None):
     return mod, params
 
 
+def build_extern_compiler(mod, compiler):
+    """Helper function that annotates a Relay module and patitions the
+    expression init into various regions. These regions will be handled
+    by either default compilers in TVM stack or the provided external compiler.
+
+    Parameters
+    ----------
+    mod : relay.Module
+        The module to build. Using relay.Function is deprecated.
+
+    compiler : str
+        The name of the external compiler.
+
+    Returns
+    -------
+    mod : relay.Module
+        The relay module contains partitioned program regions (e.g. functions)
+        that will be compiled using different compilers.
+    """
+    if isinstance(mod, _expr.Function):
+        mod = _Module.from_expr(mod)
+
+    seq = _transform.Sequential([_transform.AnnotateCompiler(compiler),
+                                 _transform.PartitionGraph()])
+    mod = seq(mod)
+    return mod
+
+
 class GraphExecutor(_interpreter.Executor):
     """Wrapper around Executor interface.
 

python/tvm/relay/op/__init__.py

@@ -19,7 +19,7 @@
 # operator defs
 from .op import get, register, register_schedule, register_compute, register_gradient, \
     register_pattern, register_alter_op_layout, register_legalize, \
-    schedule_injective, Op, OpPattern, debug
+    register_annotate_compiler, schedule_injective, Op, OpPattern, debug
 
 # Operators
 from .reduce import *

python/tvm/relay/op/annotation/annotation.py

@@ -62,6 +62,7 @@ def stop_fusion(data):
     """
     return _make.stop_fusion(data)
 
+
 def checkpoint(data):
     """Annotate an expression to be a checkpoint for the checkpointing memory optimization.
 
@@ -78,3 +79,43 @@ def checkpoint(data):
     return _make.checkpoint(data)
 
 register_schedule("annotation.checkpoint", schedule_injective)
+
+
+def compiler_begin(data, compiler):
+    """Annotate an expression to indicate that it is the beginning of
+    a regeion that will be handled by the given compiler.
+
+    Parameters
+    ----------
+    data : tvm.relay.Expr
+        The expression to be annotated.
+
+    compiler : Str
+        The compiler used to generate code of the annotated region.
+
+    Returns
+    -------
+    result : tvm.relay.Expr
+        The annotated expression.
+    """
+    return _make.compiler_begin(data, compiler)
+
+
+def compiler_end(data, compiler):
+    """Annotate an expression to indicate that it is the end of a region that
+    is handled by the provided compiler.
+
+    Parameters
+    ----------
+    data : tvm.relay.Expr
+        The expression to be annotated.
+
+    compiler : Str
+        The compiler used to generate code of the annotated region.
+
+    Returns
+    -------
+    result : tvm.relay.Expr
+        The annotated expression.
+    """
+    return _make.compiler_end(data, compiler)

python/tvm/relay/op/contrib/__init__.py

@@ -18,4 +18,5 @@
 """Neural network related operators."""
 from __future__ import absolute_import as _abs
 from .contrib import *
+from .annotate_compiler import *
 from . import _contrib

python/tvm/relay/op/contrib/annotate_compiler.py

@@ -0,0 +1,119 @@
+# 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.
+# pylint: disable=invalid-name, unused-argument
+"""
+External compiler related feature registration.
+
+It implements dispatchers that check if an operator should use a given compiler
+to generate code.
+
+Each compiler can customize the support of an operator. For example, they can
+check the attribute of the operator and/or the features of the input arguments
+to decide if we should use the compiler for codegen.
+"""
+from __future__ import absolute_import
+
+import logging
+import pkgutil
+from pathlib import Path
+from importlib import import_module
+
+from .. import op as reg
+
+logger = logging.getLogger('AnnotateCompiler')
+
+# Load available contrib compilers
+compilers = {}
+for _, name, _ in pkgutil.iter_modules([Path(__file__).parent]):
+    compilers[name] = import_module(
+        '.%s' % name, package='.'.join(__name__.split('.')[:-1]))
+
+
+def get_annotate_compiler(compiler, op_name):
+    """Get the annotate_compiler function from the registered compilers.
+
+    Parameters
+    ----------
+    compiler : Str
+        The name of a compiler that is used to generate code.
+
+    op_name : Str
+        The name of an operator.
+
+    Returns
+    -------
+    ret : bool
+        If the operator uses the provided compiler for codegen.
+    """
+    if compiler in compilers:
+        if hasattr(compilers[compiler], 'annotate_compiler'):
+            annotate_compiler = getattr(compilers[compiler], 'annotate_compiler')
+            if hasattr(annotate_compiler, op_name):
+                return getattr(annotate_compiler, op_name)
+
+    logger.warning("%s in %s is not registered. Fallback to CPU", op_name,
+                   compiler)
+    return lambda x, y: False
+
+
+@reg.register_annotate_compiler("nn.conv2d")
+def annotate_conv2d(attrs, args, compiler):
+    """Check if the provided compiler should be used for conv2d.
+    """
+    return get_annotate_compiler(compiler, 'conv2d')(attrs, args)
+
+
+@reg.register_annotate_compiler("nn.dense")
+def annotate_dense(attrs, args, compiler):
+    """Check if the provided compiler should be used for dense.
+    """
+    return get_annotate_compiler(compiler, 'dense')(attrs, args)
+
+
+@reg.register_annotate_compiler("nn.relu")
+def annotate_relu(attrs, args, compiler):
+    """Check if the provided compiler should be used for relu.
+    """
+    return get_annotate_compiler(compiler, 'relu')(attrs, args)
+
+
+@reg.register_annotate_compiler("nn.batch_norm")
+def annotate_batch_norm(attrs, args, compiler):
+    """Check if the provided compiler should be used for batch_norm.
+    """
+    return get_annotate_compiler(compiler, 'batch_norm')(attrs, args)
+
+
+@reg.register_annotate_compiler("subtract")
+def annotate_subtract(attrs, args, compiler):
+    """Check if the provided compiler should be used for subtract.
+    """
+    return get_annotate_compiler(compiler, 'subtract')(attrs, args)
+
+
+@reg.register_annotate_compiler("add")
+def annotate_add(attrs, args, compiler):
+    """Check if the provided compiler should be used for add.
+    """
+    return get_annotate_compiler(compiler, 'add')(attrs, args)
+
+
+@reg.register_annotate_compiler("multiply")
+def annotate_multiply(attrs, args, compiler):
+    """Check if the provided compiler should be used for multiply.
+    """
+    return get_annotate_compiler(compiler, 'multiply')(attrs, args)

python/tvm/relay/op/contrib/csource/__init__.py

@@ -0,0 +1,20 @@
+# 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.
+# pylint: disable=wildcard-import
+"""Neural network related operators."""
+from __future__ import absolute_import as _abs
+from .annotate_compiler import *

python/tvm/relay/op/contrib/csource/annotate_compiler.py

@@ -0,0 +1,39 @@
+# 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.
+# pylint: disable=invalid-name, unused-argument
+"""C/C++ compiler supported operators."""
+from __future__ import absolute_import
+
+def conv2d(attrs, args):
+    """Check if the external C source codegen should be used.
+    """
+    return False
+
+def subtract(attrs, args):
+    """Check if the external C source codegen should be used.
+    """
+    return True
+
+def add(attrs, args):
+    """Check if the external C source codegen should be used.
+    """
+    return True
+
+def multiply(attrs, args):
+    """Check if the external C source codegen should be used.
+    """
+    return True