[API][v0.3] Introduce Struct Data Type to HeteroCL (#157)

* initial attempt for introducing struct

* add a simple test for struct; more are coming ...

* add complex test

* errors from nn.py; need to look into that ...

* add C codegen for struct

* the previous C codegen was not complete, the other conversion direction was not taken care of

* clean up the code

hlib/python/hlib/op/nn.py

@@ -173,6 +173,7 @@ def conv2d(
     d = []
     for i in range(len(padding)):
         p.append(tvm_to_primitive(padding[i]))
+    for i in range(len(strides)):
         s.append(tvm_to_primitive(strides[i]))
         d.append(tvm_to_primitive(dilation[i]))
     strides = s

python/heterocl/api.py

@@ -90,11 +90,12 @@ def placeholder(shape, name=None, dtype=None):
     """
     name = util.get_name("placeholder", name)
     dtype = util.get_dtype(dtype)
-
+    tvm_dtype = types.dtype_to_str(dtype)
+
     if shape == ():
-        return Scalar(tvm_api._Var(name, dtype))
+        return Scalar(tvm_api._Var(name, tvm_dtype))
     tensor = Tensor(shape, dtype, name)
-    tensor.tensor = tvm_api._Placeholder(tensor.buf.shape, dtype, name)
+    tensor.tensor = tvm_api._Placeholder(tensor.buf.shape, tvm_dtype, name)
 
     # placeholder is also a stage
     stage = Stage(name)

python/heterocl/compute_api.py

@@ -5,8 +5,9 @@
 from collections import OrderedDict
 from .tvm import expr as _expr, stmt as _stmt, make as _make
 from .tvm.api import _IterVar, min_value
-from .util import get_index, get_name, get_type, get_dtype, make_for, CastRemover
+from .util import get_index, get_name, get_type, get_tvm_dtype, make_for, CastRemover
 from .tensor import Scalar, Tensor, TensorSlice
+from .types import Struct, dtype_to_str
 from .schedule import Stage
 from .debug import APIError
 from .dsl import if_, for_
@@ -117,7 +118,7 @@ def compute_body(name,
         if not return_tensor:
             stage.input_stages.add(tensor.last_update)
         else:
-            tensor = Tensor(shape, stage._dtype, name, stage._buf)
+            tensor = Tensor(shape, stage._hcl_dtype, name, stage._buf)
         buffer_var = tensor._buf.data
         dtype = tensor.dtype
         shape = tensor.shape
@@ -137,6 +138,28 @@ def compute_body(name,
             stmt = stage.pop_stmt()
             stmt = ReplaceReturn(buffer_var, dtype, index).mutate(stmt)
             stmt = make_for(indices, stmt, 0)
+        elif isinstance(ret, (tuple, list)):
+            indices = lambda_ivs
+            index, _, _ = get_index(shape, indices, 0)
+            hcl_dtype = tensor.hcl_dtype
+            if not isinstance(hcl_dtype, Struct):
+                raise TensorError("Cannot assign a tuple/list to a non-struct-type tensor")
+            start = 0
+            end = 0
+            for sdtype, expr in zip(hcl_dtype.dtype_dict.values(), ret):
+                end = start + sdtype.bits
+                sdtype = dtype_to_str(sdtype)
+                load = _make.Load(dtype, buffer_var, index)
+                expr = _make.Cast(sdtype, expr)
+                if get_type(sdtype) != "uint":
+                    ty = "uint" + str(get_type(sdtype)[1])
+                    expr = _make.Call(ty, "bitcast", [expr], _expr.Call.PureIntrinsic, None, 0)
+                expr = _make.SetSlice(load, expr, end, start)
+                stage.emit(_make.Store(buffer_var,
+                                       _make.Cast(dtype, expr),
+                                       index))
+                start = end
+            stmt = make_for(indices, stage.pop_stmt(), 0)
         elif isinstance(ret, (TensorSlice, Scalar, _expr.Expr, numbers.Number)):
             indices = lambda_ivs
             index, _, _ = get_index(shape, indices, 0)
@@ -539,7 +562,7 @@ def unpack_A(A):
         # to do so, we will need the name
         name_ = name if Stage.get_len() == 0 \
                      else Stage.get_current().name_with_prefix + "." + name
-        dtype = get_dtype(dtype, name_)
+        dtype = get_tvm_dtype(dtype, name_)
         ret = get_type(dtype)
         factor = tensor.type.bits // ret[1]
         bitwidth = ret[1]
@@ -612,7 +635,7 @@ def pack(tensor, axis=0, factor=None, name=None, dtype=None):
         # to do so, we will need the name
         name_ = name if Stage.get_len() == 0 \
                      else Stage.get_current().name_with_prefix + "." + name
-        dtype = get_dtype(dtype, name_)
+        dtype = get_tvm_dtype(dtype, name_)
         ret = get_type(dtype)
         factor = ret[1] // tensor.type.bits
         bitwidth = tensor.type.bits

python/heterocl/dsl.py

@@ -399,19 +399,19 @@ def decorator(fmodule, shapes=shapes, dtypes=dtypes, ret_dtype=ret_dtype, name=n
             if dtypes is None:
                 dtypes = []
                 for name_ in new_names:
-                    dtypes.append(util.get_dtype(None, name_))
+                    dtypes.append(util.get_tvm_dtype(None, name_))
             elif isinstance(dtypes, list):
                 if len(dtypes) != nargs:
                     raise APIError("The number of data types does not match the of arguments")
                 for (name_, dtype_) in zip(new_names, dtypes):
-                    dtypes.append(util.get_dtype(dtype_, name_))
+                    dtypes.append(util.get_tvm_dtype(dtype_, name_))
                 dtypes = dtypes[int(len(dtypes)/2):]
             else:
-                dtype = util.get_dtype(dtypes)
+                dtype = util.get_tvm_dtype(dtypes)
                 dtypes = []
                 for name_ in new_names:
-                    dtypes.append(util.get_dtype(dtype, name_))
-            ret_dtype = util.get_dtype(ret_dtype, s.name_with_prefix)
+                    dtypes.append(util.get_tvm_dtype(dtype, name_))
+            ret_dtype = util.get_tvm_dtype(ret_dtype, s.name_with_prefix)
             # prepare inputs for IR generation
             inputs = []
             inputs_tvm = []
@@ -441,7 +441,7 @@ def decorator(fmodule, shapes=shapes, dtypes=dtypes, ret_dtype=ret_dtype, name=n
             ret_void = _make.UIntImm("uint1", 0) if s.has_return else _make.UIntImm("uint1", 1)
             body = s.pop_stmt()
             s.stmt_stack.append([])
-            s.emit(_make.KernelDef(inputs_tvm, arg_shapes, arg_dtypes, 
+            s.emit(_make.KernelDef(inputs_tvm, arg_shapes, arg_dtypes,
                                    body, ret_void, ret_dtype, name, []))
             for name_, i in zip(names, inputs):
                 s.var_dict[name_] = i
@@ -499,6 +499,6 @@ def compute_out(A, x):
     if not Stage.get_len():
         raise DSLError("Imperative DSL must be used with other compute APIs")
     stage = Stage.get_current()
-    dtype = util.get_dtype(stage.ret_dtype)
+    dtype = util.get_tvm_dtype(stage.ret_dtype)
     stage.emit(_make.Return(_make.Cast(dtype, val)))
     stage.has_return = True

python/heterocl/nparray.py

@@ -2,7 +2,7 @@
 #pylint: disable=missing-docstring
 import numpy as np
 from .tvm.ndarray import array, cpu
-from .util import get_dtype
+from .util import get_tvm_dtype
 from . import types
 
 def cast_np(np_in, dtype):
@@ -79,7 +79,7 @@ def asarray(arr, dtype=None, ctx=cpu(0)):
         np_A = numpy.zeros(10)
         hcl_A = np_A.asarray()
     """
-    dtype = get_dtype(dtype)
+    dtype = get_tvm_dtype(dtype)
     return array(arr, dtype, ctx)
 
 def pack_np(np_in, dtype_in, dtype_out):

python/heterocl/schedule.py

@@ -324,7 +324,8 @@ def __init__(self, name=None, dtype=None, shape=()):
                                     else Stage.get_current().name_with_prefix + "." + self.name
         # Private attributes for building a stage
         self._op = None
-        self._dtype = util.get_dtype(dtype, self.name_with_prefix)
+        self._hcl_dtype = util.get_dtype(dtype, self.name_with_prefix)
+        self._dtype = util.get_tvm_dtype(dtype, self.name_with_prefix)
         self._buf = tvm_api.decl_buffer(shape, self._dtype, self.name)
         self._shape = self._buf.shape
 

python/heterocl/tensor.py

@@ -113,11 +113,12 @@ class TensorSlice(NodeGeneric, _expr.ExprOp):
 
         # not allowed: A[5:7]
     """
-    def __init__(self, tensor, indices):
+    def __init__(self, tensor, indices, dtype=None):
         if not isinstance(indices, tuple):
             indices = (indices,)
         self.tensor = tensor
         self.indices = indices
+        self._dtype = dtype if dtype is not None else self.tensor.dtype
 
     def __getitem__(self, indices):
         if not isinstance(indices, tuple):
@@ -134,10 +135,17 @@ def __setitem__(self, indices, expr):
         builder = Stage.get_current()
         if bit is None:
             builder.emit(_make.Store(self.tensor.buf.data,
-                                     _make.Cast(self.tensor.dtype, expr),
+                                     _make.Cast(self._dtype, expr),
                                      index))
         elif isinstance(bit, slice):
             load = _make.Load(self.tensor.dtype, self.tensor.buf.data, index)
+            # special handle for struct: we need to make sure the bitwidths
+            # are the same before and after bitcast
+            if (isinstance(self.tensor.type, types.Struct)
+                    and util.get_type(self._dtype) != "uint"):
+                ty = "uint" + str(util.get_type(self._dtype)[1])
+                expr = _make.Call(ty, "bitcast",
+                                  [expr], _expr.Call.PureIntrinsic, None, 0)
             expr = _make.SetSlice(load, expr, bit.start, bit.stop)
             builder.emit(_make.Store(self.tensor.buf.data,
                                      _make.Cast(self.tensor.dtype, expr),
@@ -146,9 +154,53 @@ def __setitem__(self, indices, expr):
             load = _make.Load(self.tensor.dtype, self.tensor.buf.data, index)
             expr = _make.SetBit(load, expr, bit)
             builder.emit(_make.Store(self.tensor.buf.data,
-                                     _make.Cast(self.tensor.dtype, expr),
+                                     _make.Cast(self._dtype, expr),
                                      index))
 
+    def __getattr__(self, key):
+        hcl_dtype = self.tensor.hcl_dtype
+        if not isinstance(hcl_dtype, types.Struct):
+            raise TensorError(
+                    "Cannot access attribute if type is not struct")
+        start = 0
+        end = 0
+        dtype = None
+        for dkey, dval in hcl_dtype.dtype_dict.items():
+            if dkey == key:
+                end = start + dval.bits
+                dtype = types.dtype_to_str(dval)
+                break
+            else:
+                start += dval.bits
+        if dtype is None:
+            raise DTypeError("Field " + key
+                             + " is not in struct " + str(hcl_dtype))
+        indices = (slice(end, start),)
+        return TensorSlice(self.tensor, self.indices + indices, dtype)
+
+    def __setattr__(self, key, expr):
+        if key in ("tensor", "indices", "_dtype"):
+            super().__setattr__(key, expr)
+        else:
+            hcl_dtype = self.tensor.hcl_dtype
+            if not isinstance(hcl_dtype, types.Struct):
+                raise TensorError(
+                        "Cannot access attribute if type is not struct")
+            start = 0
+            end = 0
+            for dkey, dval in hcl_dtype.dtype_dict.items():
+                if dkey == key:
+                    end = start + dval.bits
+                    self._dtype = types.dtype_to_str(dval)
+                    break
+                else:
+                    start += dval.bits
+            if start == end:
+                raise DTypeError("Field " + key
+                                 + " is not in struct " + str(hcl_dtype))
+            indices = (slice(end, start),)
+            self.__setitem__(indices, expr)
+
     @property
     def dtype(self):
         return self.tensor.dtype
@@ -158,12 +210,25 @@ def asnode(self):
             raise TensorError("Accessing a slice of tensor is not allowed")
         index, bit, _ = util.get_index(self.tensor.shape, self.indices, 0)
         if bit is None:
-            return _make.Load(self.tensor.dtype, self.tensor.buf.data, index)
+            return _make.Load(self._dtype, self.tensor.buf.data, index)
         elif isinstance(bit, slice):
-            return _make.GetSlice(_make.Load(self.tensor.dtype, self.tensor.buf.data, index),
+            load = _make.GetSlice(_make.Load(self.tensor.dtype,
+                                             self.tensor.buf.data, index),
                                   bit.start,
                                   bit.stop)
-        return _make.GetBit(_make.Load(self.tensor.dtype, self.tensor.buf.data, index), bit)
+            if self.tensor.dtype != self._dtype:
+                bw_from = types.get_bitwidth(self.tensor.dtype)
+                bw_to = types.get_bitwidth(self._dtype)
+                if bw_from != bw_to:
+                    ty = util.get_type(self.tensor.dtype)[0] + str(bw_to)
+                    load = _make.Cast(ty, load)
+                return _make.Call(self._dtype, "bitcast",
+                                  [load], _expr.Call.PureIntrinsic, None, 0)
+            else:
+                return load
+        return _make.GetBit(_make.Load(self._dtype,
+                                       self.tensor.buf.data,
+                                       index), bit)
 
 class Tensor(NodeGeneric, _expr.ExprOp):
     """A HeteroCL tensor.
@@ -230,14 +295,15 @@ class Tensor(NodeGeneric, _expr.ExprOp):
     def __init__(self, shape, dtype="int32", name="tensor", buf=None):
         self._tensor = None
         self._buf = buf
-        self.dtype = dtype
+        self.hcl_dtype = dtype
+        self.dtype = types.dtype_to_str(dtype)
         self.shape = shape
         self.name = name
         self.var_dict = {}
         self.first_update = None
         self.last_update = None
         if buf is None:
-            self._buf = decl_buffer(shape, dtype, name)
+            self._buf = decl_buffer(shape, self.dtype, name)
 
     def __repr__(self):
         return "Tensor('" + self.name + "', " + str(self.shape) + ", " + str(self.dtype) + ")"
@@ -291,7 +357,7 @@ def buf(self):
 
     @property
     def type(self):
-        return types.dtype_to_hcl(self.dtype)
+        return self.hcl_dtype
 
     @property
     def op(self):

python/heterocl/types.py

@@ -1,6 +1,7 @@
 """Define HeteroCL data types"""
 #pylint: disable=too-few-public-methods, too-many-return-statements
 import numbers
+from collections import OrderedDict
 from .debug import DTypeError
 
 class Type(object):
@@ -48,6 +49,30 @@ class UFixed(Type):
     def __repr__(self):
         return "UFixed(" + str(self.bits) + ", " + str(self.fracs) + ")"
 
+class Struct(Type):
+    """A C-like struct
+
+    The struct members are defined with a Python dictionary
+    """
+    def __init__(self, dtype_dict):
+        self.dtype_dict = OrderedDict(dtype_dict)
+        self.bits = 0
+        for dtype in dtype_dict.values():
+            self.bits += dtype.bits
+        Type.__init__(self, self.bits, 0)
+
+    def __repr__(self):
+        return "Struct(" + str(self.dtype_dict) + ")"
+
+    def __getattr__(self, key):
+        try:
+            return self.dtype_dict[key]
+        except KeyError:
+            raise DTypeError(key + " is not in struct")
+
+    def __getitem__(self, key):
+        return self.__getattr__(key)
+
 def dtype_to_str(dtype):
     """Convert a data type to string format.
 
@@ -66,7 +91,8 @@ def dtype_to_str(dtype):
     if isinstance(dtype, Type):
         if isinstance(dtype, Int):
             return "int" + str(dtype.bits)
-        elif isinstance(dtype, UInt):
+        # struct is treated as uint
+        elif isinstance(dtype, (UInt, Struct)):
             return "uint" + str(dtype.bits)
         elif isinstance(dtype, Fixed):
             bits = dtype.bits

python/heterocl/util.py

@@ -75,7 +75,10 @@ def get_dtype(dtype, name=None):
         dtype_ = Scheme.current.dtype_dict.get(name)
         dtype = dtype if dtype_ is None else dtype_
     dtype = config.init_dtype if dtype is None else dtype
-    return types.dtype_to_str(dtype)
+    return dtype
+
+def get_tvm_dtype(dtype, name=None):
+    return types.dtype_to_str(get_dtype(dtype, name))
 
 def true():
     return _make.UIntImm("uint1", 1)