[DoubleGrad PR #3] Supported higher-order GradNode generation (PaddlePaddle#41051)

* [Refactor] refactored eager_gen.py PR #2

* [DoubleGrad PR #1] Decoupled code generation logics for Dygraph ForwardFunctions and GradNodes

* Fixed minor issue

* Adjusted logics of GenerateNodeCreationCodes and GenerateForwardDefinition

* Fixed issues

* Supported higher-order grad node generation

* [DoubleGrad PR #4] Supported higher-order GradNode generation

* Fixed yaml typo

Author: jim19930609

paddle/fluid/eager/auto_code_generator/final_state_generator/codegen_utils.py

@@ -89,6 +89,10 @@ def FindForwardName(string):
     return string[:-5]
 
 
+def IsGradName(string):
+    return string.endswith("_grad")
+
+
 def IsPlainTensorType(string):
     plain_tensor_types = ['Tensor&', 'Tensor', 'const Tensor&', 'const Tensor']
     if string in plain_tensor_types:
@@ -166,6 +170,12 @@ def GetForwardFunctionName(string):
     return f"{string}_final_state_dygraph_function"
 
 
+def TransformGradVarNameForDoubleGradGeneration(string):
+    if IsGradName(string):
+        string = "grad_" + string[:-5]
+    return string
+
+
 ######################
 ###  Yaml Parsers  ###
 ######################