Change CTC context allocation from stack to heap using malloc

theano/tensor/nnet/ctc_wrapper.c

@@ -115,8 +115,8 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
                                  PyArrayObject ** out_costs,
                                  PyArrayObject ** out_gradients)
 {
-    ctc_context_t context;
-    ctc_context_init( &context );
+    ctc_context_t * context = (ctc_context_t *)malloc( sizeof( ctc_context_t ) );
+    ctc_context_init( context );
 
     npy_float32 * activations = NULL;
 
@@ -126,10 +126,10 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
     }
     else
     {
-        context.activations_copy = PyArray_GETCONTIGUOUS( in_activations );
-        if ( NULL != context.activations_copy )
+        context->activations_copy = PyArray_GETCONTIGUOUS( in_activations );
+        if ( NULL != context->activations_copy )
         {
-            activations = (npy_float32 *) PyArray_DATA( context.activations_copy );
+            activations = (npy_float32 *) PyArray_DATA( context->activations_copy );
         }
         else
         {
@@ -139,9 +139,9 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
         }
     }
 
-    create_contiguous_input_lengths( in_input_lengths, &(context.input_lengths) );
+    create_contiguous_input_lengths( in_input_lengths, &(context->input_lengths) );
 
-    if ( NULL == context.input_lengths )
+    if ( NULL == context->input_lengths )
     {
         PyErr_Format( PyExc_MemoryError,
             "Could not allocate storage for input lengths" );
@@ -149,12 +149,12 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
     }
 
     // flatten labels to conform with library memory layout
-    create_flat_labels( in_labels, &(context.flat_labels), &(context.label_lengths) );
+    create_flat_labels( in_labels, &(context->flat_labels), &(context->label_lengths) );
 
-    if ( ( NULL == context.label_lengths ) || ( NULL == context.flat_labels ) )
+    if ( ( NULL == context->label_lengths ) || ( NULL == context->flat_labels ) )
     {
         // Destroy previous CTC context before returning exception
-        ctc_context_destroy( &context );
+        ctc_context_destroy( context );
 
         PyErr_Format( PyExc_MemoryError,
             "Could not allocate storage for labels and their lengths" );
@@ -178,7 +178,7 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
         if ( NULL == (*out_costs) )
         {
             // Destroy previous CTC context before returning exception
-            ctc_context_destroy( &context );
+            ctc_context_destroy( context );
 
             PyErr_Format( PyExc_MemoryError,
                 "Could not allocate storage for CTC costs" );
@@ -204,7 +204,7 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
         if ( NULL == (*out_gradients) )
         {
             // Destroy previous CTC context before returning exception
-            ctc_context_destroy( &context );
+            ctc_context_destroy( context );
 
             PyErr_Format( PyExc_MemoryError,
                 "Could not allocate storage for CTC gradients!" );
@@ -217,20 +217,20 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
     size_t cpu_workspace_size;
     int ctc_error;
 
-    ctc_error = ctc_check_result( get_workspace_size( context.label_lengths,
-        context.input_lengths, alphabet_size, minibatch_size, context.options,
+    ctc_error = ctc_check_result( get_workspace_size( context->label_lengths,
+        context->input_lengths, alphabet_size, minibatch_size, context->options,
         &cpu_workspace_size ),
         "Failed to obtain CTC workspace size!" );
 
     if ( ctc_error )  // Exception is set by ctc_check_result, return error here
         return 1;
 
-    context.workspace = malloc( cpu_workspace_size );
+    context->workspace = malloc( cpu_workspace_size );
 
-    if ( NULL == context.workspace )
+    if ( NULL == context->workspace )
     {
         // Destroy previous CTC context before returning exception
-        ctc_context_destroy( &context );
+        ctc_context_destroy( context );
 
         PyErr_Format( PyExc_MemoryError,
             "Failed to allocate memory for CTC workspace!" );
@@ -238,14 +238,15 @@ int APPLY_SPECIFIC(ctc_cost_cpu)(PyArrayObject *  in_activations,
     }
 
     ctc_error = ctc_check_result( compute_ctc_loss( activations, gradients,
-        context.flat_labels, context.label_lengths, context.input_lengths,
-        alphabet_size, minibatch_size, costs, context.workspace, context.options ),
+        context->flat_labels, context->label_lengths, context->input_lengths,
+        alphabet_size, minibatch_size, costs, context->workspace, context->options ),
         "Failed to compute CTC loss function!" );
 
     if ( ctc_error )  // Exception is set by ctc_check_result, return error here
         return 1;
 
-    ctc_context_destroy( &context );
+    ctc_context_destroy( context );
+    free( context );
 
     return 0;
 }