From d48ae14dad71adf876a72cd63af944dc4fed68c8 Mon Sep 17 00:00:00 2001
From: Matthew Barrett <matthew.barrett@arm.com>
Date: Thu, 29 Oct 2020 16:06:53 +0000
Subject: [PATCH] Create UpdateConstants utility function

Change-Id: I73c8c6f92cfe3be3a7e811e98a4eec17590186ff
---
 src/relay/backend/graph_runtime_codegen.cc | 27 +------------------
 src/relay/backend/utils.h                  | 31 ++++++++++++++++++++++
 src/relay/backend/vm/compiler.cc           | 21 +--------------
 3 files changed, 33 insertions(+), 46 deletions(-)

diff --git a/src/relay/backend/graph_runtime_codegen.cc b/src/relay/backend/graph_runtime_codegen.cc
index 655fdf013d1ea..e24d18de931c8 100644
--- a/src/relay/backend/graph_runtime_codegen.cc
+++ b/src/relay/backend/graph_runtime_codegen.cc
@@ -368,32 +368,7 @@ class GraphRuntimeCodegen : public backend::MemoizedExprTranslator<std::vector<G
       CCacheKey key = (*pf0)(func, target);
       CachedFunc ext_func = (*pf1)(compile_engine_, key);
       ICHECK(ext_func.defined()) << "External function is not defined.";
-
-      // Step into the functions that are handled by external codegen to
-      // collect metadata.
-      auto codegen = func->GetAttr<String>(attr::kCompiler);
-      ICHECK(codegen.defined()) << "No external codegen is set";
-      std::string codegen_name = codegen.value();
-      const auto name_node = func->GetAttr<String>(tvm::attr::kGlobalSymbol);
-      std::string symbol = std::string(name_node.value());
-      std::string const_update_name = "relay.ext." + codegen_name + ".constant_updater";
-      // Get the constant updater for the external codegen
-      auto pf = tvm::runtime::Registry::Get(const_update_name);
-      // If the backend hasn't registered a constant updater, use a default one
-      if (pf == nullptr) {
-        ConstantUpdater const_visit(symbol, &params_);
-        const_visit(func);
-      } else {
-        Map<String, tvm::runtime::NDArray> constants = (*pf)(func, symbol);
-        for (const auto& it : constants) {
-          std::string const_name(it.first);
-          // Constant names should begin this the compiler name (to avoid conflicts)
-          ICHECK(const_name.find(codegen_name) == 0)
-              << "External constant names must start with compiler name";
-          params_[const_name] = it.second;
-        }
-      }
-
+      UpdateConstants(func, &params_);
       return GraphAddCallNode(op, ext_func->func_name, ext_func->func_name);
     }
 
diff --git a/src/relay/backend/utils.h b/src/relay/backend/utils.h
index 3def6359c6153..4426642e8e18b 100644
--- a/src/relay/backend/utils.h
+++ b/src/relay/backend/utils.h
@@ -63,6 +63,37 @@ struct ConstantUpdater : public ExprVisitor {
   std::unordered_map<std::string, runtime::NDArray>* params_;
 };
 
+/*!
+ * \brief A function to update the params with constants found in an external function.
+ * \param func The function from which to get the constant params.
+ * \param params The params to update with the constants.
+ */
+inline void UpdateConstants(Function func,
+                            std::unordered_map<std::string, runtime::NDArray>* params) {
+  auto codegen = func->GetAttr<String>(attr::kCompiler);
+  ICHECK(codegen.defined()) << "No external codegen is set";
+  std::string codegen_name = codegen.value();
+  const auto name_node = func->GetAttr<String>(tvm::attr::kGlobalSymbol);
+  std::string symbol = std::string(name_node.value());
+  std::string const_update_name = "relay.ext." + codegen_name + ".constant_updater";
+  // Get the constant updater for the external codegen
+  auto pf = tvm::runtime::Registry::Get(const_update_name);
+  // If the backend hasn't registered a constant updater, use a default one
+  if (pf == nullptr) {
+    ConstantUpdater const_visit(symbol, params);
+    const_visit(func);
+  } else {
+    Map<String, tvm::runtime::NDArray> constants = (*pf)(func, symbol);
+    for (const auto& it : constants) {
+      std::string const_name(it.first);
+      // Constant names should begin this the compiler name (to avoid conflicts)
+      ICHECK(const_name.find(codegen_name) == 0)
+          << "External constant names must start with compiler name";
+      (*params)[const_name] = it.second;
+    }
+  }
+}
+
 /*!
  * \brief A simple wrapper around ExprFunctor for a single argument case.
  *  The result of visit is memoized.
diff --git a/src/relay/backend/vm/compiler.cc b/src/relay/backend/vm/compiler.cc
index 8b8a38f00e845..f652644afa3c3 100644
--- a/src/relay/backend/vm/compiler.cc
+++ b/src/relay/backend/vm/compiler.cc
@@ -1125,26 +1125,7 @@ void VMCompiler::Codegen() {
       // Collect metadata in functions that are handled by external codegen.
       ICHECK(mod->ContainGlobalVar(cfunc->func_name));
       Function func = Downcast<Function>(mod->Lookup(cfunc->func_name));
-      auto codegen = func->GetAttr<String>(attr::kCompiler);
-      ICHECK(codegen.defined()) << "No external codegen is set";
-      std::string codegen_name = codegen.value();
-      std::string const_update_name = "relay.ext." + codegen_name + ".constant_updater";
-      // Get the constant updater for the external codegen
-      auto pf = tvm::runtime::Registry::Get(const_update_name);
-      // If the backend hasn't registered a constant updater, use a default one
-      if (pf == nullptr) {
-        backend::ConstantUpdater const_visit(cfunc->func_name, &params_);
-        const_visit(func);
-      } else {
-        Map<String, tvm::runtime::NDArray> constants = (*pf)(func, cfunc->func_name);
-        for (const auto& it : constants) {
-          std::string const_name(it.first);
-          // Constant names should begin this the compiler name (to avoid conflicts)
-          ICHECK(const_name.find(codegen_name) == 0)
-              << "External constant names must start with compiler name";
-          params_[const_name] = it.second;
-        }
-      }
+      backend::UpdateConstants(func, &params_);
       continue;
     } else if (funcs.count(target_str) == 0) {
       funcs.emplace(target_str, mod);