DataOffloadTrafo: added option to declare kernel args as true device …

…pointers

cmake/loki_transform.cmake

@@ -199,7 +199,7 @@ endmacro()
 
 function( loki_transform_convert )
 
-    set( options CPP DATA_OFFLOAD REMOVE_OPENMP GLOBAL_VAR_OFFLOAD TRIM_VECTOR_SECTIONS REMOVE_DERIVED_ARGS )
+    set( options CPP DATA_OFFLOAD REMOVE_OPENMP DEVICEPTR GLOBAL_VAR_OFFLOAD TRIM_VECTOR_SECTIONS REMOVE_DERIVED_ARGS )
     set( oneValueArgs MODE DIRECTIVE FRONTEND CONFIG PATH OUTPATH )
     set( multiValueArgs OUTPUT DEPENDS INCLUDES INCLUDE HEADERS HEADER DEFINITIONS DEFINE OMNI_INCLUDE XMOD )
 
@@ -236,6 +236,10 @@ function( loki_transform_convert )
         list( APPEND _ARGS --remove-openmp )
     endif()
 
+    if( ${_PAR_DEVICEPTR} )
+        list( APPEND _ARGS --deviceptr )
+    endif()
+
     if( ${_PAR_GLOBAL_VAR_OFFLOAD} )
         list( APPEND _ARGS --global-var-offload )
     endif()

scripts/loki_transform.py

@@ -96,6 +96,8 @@ def cli(debug):
               help='Run transformation to insert custom data offload regions.')
 @click.option('--remove-openmp', is_flag=True, default=False,
               help='Removes existing OpenMP pragmas in "!$loki data" regions.')
+@click.option('--deviceptr', is_flag=True, default=False,
+              help='Mark the relevant arguments as true device-pointers in "!$loki data" regions.')
 @click.option('--frontend', default='fp', type=click.Choice(['fp', 'ofp', 'omni']),
               help='Frontend parser to use (default FP)')
 @click.option('--trim-vector-sections', is_flag=True, default=False,
@@ -106,7 +108,7 @@ def cli(debug):
               help="Remove derived-type arguments and replace with canonical arguments")
 def convert(
         mode, config, build, source, header, cpp, directive, include, define, omni_include, xmod,
-        data_offload, remove_openmp, frontend, trim_vector_sections,
+        data_offload, remove_openmp, deviceptr, frontend, trim_vector_sections,
         global_var_offload, remove_derived_args
 ):
     """
@@ -169,7 +171,7 @@ def convert(
     # Insert data offload regions for GPUs and remove OpenMP threading directives
     use_claw_offload = True
     if data_offload:
-        offload_transform = DataOffloadTransformation(remove_openmp=remove_openmp)
+        offload_transform = DataOffloadTransformation(remove_openmp=remove_openmp, deviceptr=deviceptr)
         scheduler.process(transformation=offload_transform)
         use_claw_offload = not offload_transform.has_data_regions
 

transformations/tests/test_data_offload.py

@@ -9,14 +9,15 @@
 
 from loki import (
     Sourcefile, FindNodes, Pragma, PragmaRegion, Loop,
-    CallStatement, pragma_regions_attached
+    CallStatement, pragma_regions_attached, get_pragma_parameters
 )
 from conftest import available_frontends
 from transformations import DataOffloadTransformation
 
 
 @pytest.mark.parametrize('frontend', available_frontends())
-def test_data_offload_region_openacc(frontend):
+@pytest.mark.parametrize('deviceptr', [True, False])
+def test_data_offload_region_openacc(frontend, deviceptr):
     """
     Test the creation of a simple device data offload region
     (`!$acc update`) from a `!$loki data` region with a single
@@ -56,14 +57,20 @@ def test_data_offload_region_openacc(frontend):
     kernel = Sourcefile.from_source(fcode_kernel, frontend=frontend)['kernel_routine']
     driver.enrich_calls(kernel)
 
-    driver.apply(DataOffloadTransformation(), role='driver', targets=['kernel_routine'])
-
-    assert len(FindNodes(Pragma).visit(driver.body)) == 2
-    assert all(p.keyword == 'acc' for p in FindNodes(Pragma).visit(driver.body))
-    transformed = driver.to_fortran()
-    assert 'copyin( a )' in transformed
-    assert 'copy( b )' in transformed
-    assert 'copyout( c )' in transformed
+    driver.apply(DataOffloadTransformation(deviceptr=deviceptr), role='driver', targets=['kernel_routine'])
+
+    pragmas = FindNodes(Pragma).visit(driver.body)
+    assert len(pragmas) == 2
+    assert all(p.keyword == 'acc' for p in pragmas)
+    if deviceptr:
+        assert 'deviceptr' in pragmas[0].content
+        params = get_pragma_parameters(pragmas[0], only_loki_pragmas=False)
+        assert all(var in params['deviceptr'] for var in ('a', 'b', 'c'))
+    else:
+        transformed = driver.to_fortran()
+        assert 'copyin( a )' in transformed
+        assert 'copy( b )' in transformed
+        assert 'copyout( c )' in transformed
 
 
 @pytest.mark.parametrize('frontend', available_frontends())

transformations/transformations/data_offload.py

@@ -27,13 +27,17 @@ class DataOffloadTransformation(Transformation):
     ----------
     remove_openmp : bool
         Remove any existing OpenMP pragmas inside the marked region.
+    deviceptr : bool
+        Mark all offloaded arrays as true device-pointers if data offload
+        is being managed outside of structured Openacc data regions.
     """
 
     def __init__(self, **kwargs):
         # We need to record if we actually added any, so
         # that down-stream processing can use that info
         self.has_data_regions = False
         self.remove_openmp = kwargs.get('remove_openmp', False)
+        self.deviceptr = kwargs.get('deviceptr', False)
 
     def transform_subroutine(self, routine, **kwargs):
         """
@@ -134,10 +138,16 @@ def insert_data_offload_pragmas(self, routine, targets):
                 inoutargs = tuple(dict.fromkeys(inoutargs))
 
                 # Now geenerate the pre- and post pragmas (OpenACC)
-                copyin = f'copyin({", ".join(inargs)})' if inargs else ''
-                copy = f'copy({", ".join(inoutargs)})' if inoutargs else ''
-                copyout = f'copyout({", ".join(outargs)})' if outargs else ''
-                pragma = Pragma(keyword='acc', content=f'data {copyin} {copy} {copyout}')
+                if self.deviceptr:
+                    deviceptr = ''
+                    if inargs+outargs+inoutargs:
+                        deviceptr = f'deviceptr({", ".join(inargs+outargs+inoutargs)})'
+                    pragma = Pragma(keyword='acc', content=f'data {deviceptr}')
+                else:
+                    copyin = f'copyin({", ".join(inargs)})' if inargs else ''
+                    copy = f'copy({", ".join(inoutargs)})' if inoutargs else ''
+                    copyout = f'copyout({", ".join(outargs)})' if outargs else ''
+                    pragma = Pragma(keyword='acc', content=f'data {copyin} {copy} {copyout}')
                 pragma_post = Pragma(keyword='acc', content='end data')
                 pragma_map[region.pragma] = pragma
                 pragma_map[region.pragma_post] = pragma_post