Reference model update for control flow operators support

Rationale for making this change:
- In the original design, for control flow operators like WhileOp,
child blocks couldn't read the tensor variables (global consts) in the root level block,
this patch added the machanism for child blocks to access their parent
level block's tensors.
- This change also relies on another serialization change on adding
another layer of abtraction called Region:
  - Serialization patch: [region] Add TosaSerializationRegion to serialization_lib
  - Updated the corresponding python version of the serialization code: TosaSerializerRegion to python version of serialization_lib
- This change also relies on the TOSA MLIR Translator change: Add RegionBuilder to TOSA MLIR Translator
- Added the WhileOp related test cases: While, LSTM, GRU, RNN
- Other related fixes

Signed-off-by: Jerry Ge <jerry.ge@arm.com>
Change-Id: I13ae33628ad07e41d248e88652ce1328654694ab

1 files changed, 12 insertions, 13 deletions

diff --git a/reference_model/src/ops/control_flow.cc b/reference_model/src/ops/control_flow.cc
index 7105caf..942652d 100644
--- a/reference_model/src/ops/control_flow.cc
+++ b/reference_model/src/ops/control_flow.cc
@@ -1,5 +1,5 @@
 
-// Copyright (c) 2020, ARM Limited.
+// Copyright (c) 2020-2023, ARM Limited.
 //
 //    Licensed under the Apache License, Version 2.0 (the "License");
 //    you may not use this file except in compliance with the License.
@@ -15,7 +15,6 @@
 
 #include "control_flow.h"
 #include "subgraph_traverser.h"
-
 using namespace TosaReference;
 using namespace Eigen;
 using namespace tosa;
@@ -37,7 +36,7 @@ int OpControlFlow::evalBlock(TosaSerializationBasicBlock* block,
 
     DEBUG_MED(OP, "Evaluating block %s", block_name.c_str());
 
-    SubgraphTraverser block_sgt(block, tsh);
+    SubgraphTraverser block_sgt(block, tsh, this->parent_sgt);
 
     ERROR_IF(block_sgt.initializeGraph(), "evalBlock(): Unable to initialize graph traverser for %s",
              block_name.c_str());
@@ -182,8 +181,10 @@ int OpCondIf::checkTensorAttributes()
     cond = dynamic_cast<TosaReference::Tensor0<bool>*>(inputs[0]);
     ASSERT_MEM(cond);
 
-    then_block = tsh->GetBlockByName(attribute->then_branch());
-    else_block = tsh->GetBlockByName(attribute->else_branch());
+    auto region_name = getParentSGT()->getRegionName();
+    auto curr_region = tsh->GetRegionByName(region_name);
+    then_block = curr_region->GetBlockByName(attribute->then_branch());
+    else_block = curr_region->GetBlockByName(attribute->else_branch());
 
     ERROR_IF(!then_block, "OpCondIf: fail to resolve then_branch %s", attribute->then_branch().c_str());
 
@@ -193,6 +194,7 @@ int OpCondIf::checkTensorAttributes()
     // Skip the first rank 0 bool tensor on input list
     int32_t num_input_tensor  = getInputs().size() - 1;
     int32_t num_output_tensor = getOutputs().size();
+
     ERROR_IF((int32_t)then_block->GetInputs().size() != num_input_tensor,
              "OpCondIf: then_block has unexpected number of input");
     ERROR_IF((int32_t)else_block->GetInputs().size() != num_input_tensor,
@@ -307,8 +309,10 @@ int OpWhileLoop::checkTensorAttributes()
         return 1;
     }
 
-    cond_block = tsh->GetBlockByName(attribute->cond_branch());
-    body_block = tsh->GetBlockByName(attribute->body_branch());
+    auto region_name = getParentSGT()->getRegionName();
+    auto curr_region = tsh->GetRegionByName(region_name);
+    cond_block = curr_region->GetBlockByName(attribute->cond_branch());
+    body_block = curr_region->GetBlockByName(attribute->body_branch());
 
     ERROR_IF(!cond_block, "OpWhileLoop: fail to resolve cond_branch %s", attribute->cond_branch().c_str());
     ERROR_IF(!body_block, "OpWhileLoop: fail to resolve body_branch %s", attribute->body_branch().c_str());
@@ -403,12 +407,7 @@ int OpWhileLoop::eval()
             // assigning output tensors value back to input tensors value for next iteration
             for (size_t i = 0; i < num_input_output; i++)
             {
-                if (getInputs()[i]->copyValueFrom(getOutputs()[i]))
-                {
-                    WARNING("Fail to copy tensor value %s -> %s", getOutputs()[i]->getName().c_str(),
-                            getInputs()[i]->getName().c_str());
-                    return 1;
-                }
+                getInputs()[i] = getOutputs()[i];
             }
         }
         else