add program check

test=develop

paddle/fluid/framework/ir/graph.cc

@@ -23,8 +23,59 @@ limitations under the License. */
 namespace paddle {
 namespace framework {
 namespace ir {
+namespace {
+void CheckProgram(const ProgramDesc &program) {
+  std::map<int, bool> visit;
+#define _INT(role) static_cast<int>(role)
+
+  for (size_t i = 0; i < program.Size(); ++i) {
+    for (OpDesc *op : program.Block(i).AllOps()) {
+      int role_id = boost::get<int>(
+          op->GetAttr(OpProtoAndCheckerMaker::OpRoleAttrName()));
+      visit[role_id] = true;
+      switch (role_id) {
+        case _INT(OpRole::kForward):
+          PADDLE_ENFORCE(
+              visit.find(_INT(OpRole::kBackward)) == visit.end(),
+              "Cannot add forward operator before backward operator.");
+          break;
+        case _INT(OpRole::kBackward):
+        case _INT(OpRole::kBackward) | _INT(OpRole::kLoss):
+          PADDLE_ENFORCE(
+              visit.find(_INT(OpRole::kOptimize)) == visit.end(),
+              "Cannot add backward operator before optimize operator.");
+          break;
+        case _INT(OpRole::kForward) | _INT(OpRole::kLoss):
+          PADDLE_ENFORCE(visit.find(_INT(OpRole::kBackward) |
+                                    _INT(OpRole::kLoss)) == visit.end(),
+                         "Cannot add backward|loss operator before "
+                         "forward|loss operator.");
+          PADDLE_ENFORCE(
+              visit.find(_INT(OpRole::kOptimize)) == visit.end(),
+              "Cannot add backward operator before optimize operator.");
+          break;
+        case _INT(OpRole::kOptimize):
+        case _INT(OpRole::kOptimize) | _INT(OpRole::kLRSched):
+          PADDLE_ENFORCE(visit.find(_INT(OpRole::kBackward)) != visit.end(),
+                         "Optimize operators must follow backward operator.");
+          break;
+        case _INT(OpRole::kLRSched):
+        case _INT(OpRole::kDist):
+        case _INT(OpRole::kRPC):
+        case _INT(OpRole::kNotSpecified):
+          break;
+        default:
+          LOG(FATAL) << "Unknown operator role. Don't add new role because "
+                        "you don't know what you are doing.";
+      }
+    }
+  }
+#undef _INT
+}
+}  // namespace
 
 Graph::Graph(const ProgramDesc &program) : program_(program) {
+  CheckProgram(program_);
   // Make the nodes id start from 0.
   Node::ResetId();
   auto var_nodes = InitFromProgram(program_);