diff --git a/src/pystencils/backend/constants.py b/src/pystencils/backend/constants.py
index 6dc07842ff12a1aadeedd37b15e3ee8c8185ebe9..125c1149ba7fec7ce279afef089229f70c75eb18 100644
--- a/src/pystencils/backend/constants.py
+++ b/src/pystencils/backend/constants.py
@@ -59,9 +59,14 @@ class PsConstant:
@property
def dtype(self) -> PsNumericType | None:
+ """This constant's data type, or ``None`` if it is untyped.
+
+ The data type of a constant always has ``const == True``.
+ """
return self._dtype
def get_dtype(self) -> PsNumericType:
+ """Retrieve this constant's data type, throwing an exception if the constant is untyped."""
if self._dtype is None:
raise PsInternalCompilerError("Data type of constant was not set.")
return self._dtype
diff --git a/src/pystencils/backend/kernelcreation/typification.py b/src/pystencils/backend/kernelcreation/typification.py
index d2c93e22109c4970ad5bb8915e7c6c8cc84173d6..190cd9e23b715ac5bca2a4bc6fd119013376cb49 100644
--- a/src/pystencils/backend/kernelcreation/typification.py
+++ b/src/pystencils/backend/kernelcreation/typification.py
@@ -12,7 +12,7 @@ from ...types import (
PsDereferencableType,
PsPointerType,
PsBoolType,
- deconstify,
+ constify,
)
from ..ast.structural import (
PsAstNode,
@@ -21,6 +21,7 @@ from ..ast.structural import (
PsConditional,
PsExpression,
PsAssignment,
+ PsDeclaration,
)
from ..ast.expressions import (
PsArrayAccess,
@@ -54,20 +55,48 @@ NodeT = TypeVar("NodeT", bound=PsAstNode)
class TypeContext:
- def __init__(self, target_type: PsType | None = None):
- self._target_type = deconstify(target_type) if target_type is not None else None
+ """Typing context, with support for type inference and checking.
+
+ Instances of this class are used to propagate and check data types across expression subtrees
+ of the AST. Each type context has:
+
+ - A target type `target_type`, which shall be applied to all expressions it covers
+ - A set of restrictions on the target type:
+ - `require_nonconst` to make sure the target type is not `const`, as required on assignment left-hand sides
+ - Additional restrictions may be added in the future.
+ """
+
+ def __init__(
+ self, target_type: PsType | None = None, require_nonconst: bool = False
+ ):
+ self._require_nonconst = require_nonconst
self._deferred_exprs: list[PsExpression] = []
- def apply_dtype(self, expr: PsExpression | None, dtype: PsType):
- """Applies the given ``dtype`` to the given expression inside this type context.
+ self._target_type = (
+ self._fix_constness(target_type) if target_type is not None else None
+ )
+
+ @property
+ def target_type(self) -> PsType | None:
+ return self._target_type
+
+ @property
+ def require_nonconst(self) -> bool:
+ return self._require_nonconst
+
+ def apply_dtype(self, dtype: PsType, expr: PsExpression | None = None):
+ """Applies the given ``dtype`` to this type context, and optionally to the given expression.
- The given expression will be covered by this type context.
If the context's target_type is already known, it must be compatible with the given dtype.
If the target type is still unknown, target_type is set to dtype and retroactively applied
to all deferred expressions.
+
+ If an expression is specified, it will be covered by the type context.
+ If the expression already has a data type set, it must be compatible with the target type
+ and will be replaced by it.
"""
- dtype = deconstify(dtype)
+ dtype = self._fix_constness(dtype)
if self._target_type is not None and dtype != self._target_type:
raise TypificationError(
@@ -80,14 +109,7 @@ class TypeContext:
self._propagate_target_type()
if expr is not None:
- if expr.dtype is None:
- self._apply_target_type(expr)
- elif deconstify(expr.dtype) != self._target_type:
- raise TypificationError(
- "Type conflict: Predefined expression type did not match the context's target type\n"
- f" Expression type: {dtype}\n"
- f" Target type: {self._target_type}"
- )
+ self._apply_target_type(expr)
def infer_dtype(self, expr: PsExpression):
"""Infer the data type for the given expression.
@@ -96,7 +118,8 @@ class TypeContext:
Otherwise, the expression is deferred, and a type will be applied to it as soon as `apply_type` is
called on this context.
- If the expression already has a data type set, it must be equal to the inferred type.
+ If the expression already has a data type set, it must be compatible with the target type
+ and will be replaced by it.
"""
if self._target_type is None:
@@ -113,7 +136,7 @@ class TypeContext:
assert self._target_type is not None
if expr.dtype is not None:
- if deconstify(expr.dtype) != self.target_type:
+ if not self._compatible(expr.dtype):
raise TypificationError(
f"Type mismatch at expression {expr}: Expression type did not match the context's target type\n"
f" Expression type: {expr.dtype}\n"
@@ -128,7 +151,7 @@ class TypeContext:
)
if c.dtype is None:
expr.constant = c.interpret_as(self._target_type)
- elif deconstify(c.dtype) != self._target_type:
+ elif not self._compatible(c.dtype):
raise TypificationError(
f"Type mismatch at constant {c}: Constant type did not match the context's target type\n"
f" Constant type: {c.dtype}\n"
@@ -136,7 +159,13 @@ class TypeContext:
)
case PsSymbolExpr(symb):
- symb.apply_dtype(self._target_type)
+ assert symb.dtype is not None
+ if not self._compatible(symb.dtype):
+ raise TypificationError(
+ f"Type mismatch at symbol {symb}: Symbol type did not match the context's target type\n"
+ f" Symbol type: {symb.dtype}\n"
+ f" Target type: {self._target_type}"
+ )
case (
PsIntDiv()
@@ -151,18 +180,42 @@ class TypeContext:
f" Expression: {expr}"
f" Type Context: {self._target_type}"
)
-
- expr.dtype = self._target_type
# endif
+ expr.dtype = self._target_type
- @property
- def target_type(self) -> PsType | None:
- return self._target_type
+ def _compatible(self, dtype: PsType):
+ """Checks whether the given data type is compatible with the context's target type.
+
+ If the target type is ``const``, they must be equal up to const qualification;
+ if the target type is not ``const``, `dtype` must match it exactly.
+ """
+ assert self._target_type is not None
+ if self._target_type.const:
+ return constify(dtype) == self._target_type
+ else:
+ return dtype == self._target_type
+
+ def _fix_constness(self, dtype: PsType, expr: PsExpression | None = None):
+ if self._require_nonconst:
+ if dtype.const:
+ if expr is None:
+ raise TypificationError(
+ f"Type mismatch: Encountered {dtype} in non-constant context."
+ )
+ else:
+ raise TypificationError(
+ f"Type mismatch at expression {expr}: Encountered {dtype} in non-constant context."
+ )
+ return dtype
+ else:
+ return constify(dtype)
class Typifier:
"""Apply data types to expressions.
+ **Contextual Typing**
+
The Typifier will traverse the AST and apply a contextual typing scheme to figure out
the data types of all encountered expressions.
To this end, it covers each expression tree with a set of disjoint typing contexts.
@@ -183,6 +236,21 @@ class Typifier:
in the context, the expression is deferred by storing it in the context, and will be assigned a type as soon
as the target type is fixed.
+ **Typing Rules**
+
+ The following general rules apply:
+
+ - The context's `default_dtype` is applied to all untyped symbols
+ - By default, all expressions receive a ``const`` type unless they occur on a (non-declaration) assignment's
+ left-hand side
+
+ **Typing of symbol expressions**
+
+ Some expressions (`PsSymbolExpr`, `PsArrayAccess`) encapsulate symbols and inherit their data types, but
+ not necessarily their const-qualification.
+ A symbol with non-``const`` type may occur in a `PsSymbolExpr` with ``const`` type,
+ and an array base pointer with non-``const`` base type may be nested in a ``const`` `PsArrayAccess`,
+ but not vice versa.
"""
def __init__(self, ctx: KernelCreationContext):
@@ -213,13 +281,21 @@ class Typifier:
for s in statements:
self.visit(s)
- case PsAssignment(lhs, rhs):
+ case PsDeclaration(lhs, rhs):
tc = TypeContext()
# LHS defines target type; type context carries it to RHS
self.visit_expr(lhs, tc)
assert tc.target_type is not None
self.visit_expr(rhs, tc)
+ case PsAssignment(lhs, rhs):
+ tc_lhs = TypeContext(require_nonconst=True)
+ self.visit_expr(lhs, tc_lhs)
+ assert tc_lhs.target_type is not None
+
+ tc_rhs = TypeContext(tc_lhs.target_type, require_nonconst=False)
+ self.visit_expr(rhs, tc_rhs)
+
case PsConditional(cond, branch_true, branch_false):
cond_tc = TypeContext(PsBoolType(const=True))
self.visit_expr(cond, cond_tc)
@@ -233,10 +309,10 @@ class Typifier:
if ctr.symbol.dtype is None:
ctr.symbol.apply_dtype(self._ctx.index_dtype)
- tc = TypeContext(ctr.symbol.dtype)
- self.visit_expr(start, tc)
- self.visit_expr(stop, tc)
- self.visit_expr(step, tc)
+ tc_index = TypeContext(ctr.symbol.dtype)
+ self.visit_expr(start, tc_index)
+ self.visit_expr(stop, tc_index)
+ self.visit_expr(step, tc_index)
self.visit(body)
@@ -244,24 +320,35 @@ class Typifier:
raise NotImplementedError(f"Can't typify {node}")
def visit_expr(self, expr: PsExpression, tc: TypeContext) -> None:
- """Recursive processing of expression nodes"""
+ """Recursive processing of expression nodes.
+
+ This method opens, expands, and closes typing contexts according to the respective expression's
+ typing rules. It may add or check restrictions only when opening or closing a type context.
+
+ The actual type inference and checking during context expansion are performed by the methods
+ of `TypeContext`. ``visit_expr`` tells the typing context how to handle an expression by calling
+ either ``apply_dtype`` or ``infer_dtype``.
+ """
match expr:
case PsSymbolExpr(_):
- if expr.dtype is None:
- tc.apply_dtype(expr, self._ctx.default_dtype)
- else:
- tc.apply_dtype(expr, expr.dtype)
+ if expr.symbol.dtype is None:
+ expr.symbol.dtype = self._ctx.default_dtype
- case PsConstantExpr(_):
- tc.infer_dtype(expr)
+ tc.apply_dtype(expr.symbol.dtype, expr)
+
+ case PsConstantExpr(c):
+ if c.dtype is not None:
+ tc.apply_dtype(c.dtype, expr)
+ else:
+ tc.infer_dtype(expr)
case PsArrayAccess(bptr, idx):
- tc.apply_dtype(expr, bptr.array.element_type)
+ tc.apply_dtype(bptr.array.element_type, expr)
index_tc = TypeContext()
self.visit_expr(idx, index_tc)
if index_tc.target_type is None:
- index_tc.apply_dtype(idx, self._ctx.index_dtype)
+ index_tc.apply_dtype(self._ctx.index_dtype, idx)
elif not isinstance(index_tc.target_type, PsIntegerType):
raise TypificationError(
f"Array index is not of integer type: {idx} has type {index_tc.target_type}"
@@ -276,12 +363,12 @@ class Typifier:
"Type of subscript base is not subscriptable."
)
- tc.apply_dtype(expr, arr_tc.target_type.base_type)
+ tc.apply_dtype(arr_tc.target_type.base_type, expr)
index_tc = TypeContext()
self.visit_expr(idx, index_tc)
if index_tc.target_type is None:
- index_tc.apply_dtype(idx, self._ctx.index_dtype)
+ index_tc.apply_dtype(self._ctx.index_dtype, idx)
elif not isinstance(index_tc.target_type, PsIntegerType):
raise TypificationError(
f"Subscript index is not of integer type: {idx} has type {index_tc.target_type}"
@@ -296,7 +383,7 @@ class Typifier:
"Type of argument to a Deref is not dereferencable"
)
- tc.apply_dtype(expr, ptr_tc.target_type.base_type)
+ tc.apply_dtype(ptr_tc.target_type.base_type, expr)
case PsAddressOf(arg):
arg_tc = TypeContext()
@@ -308,10 +395,11 @@ class Typifier:
)
ptr_type = PsPointerType(arg_tc.target_type, True)
- tc.apply_dtype(expr, ptr_type)
+ tc.apply_dtype(ptr_type, expr)
case PsLookup(aggr, member_name):
- aggr_tc = TypeContext(None)
+ # Members of a struct type inherit the struct type's `const` qualifier
+ aggr_tc = TypeContext(None, require_nonconst=tc.require_nonconst)
self.visit_expr(aggr, aggr_tc)
aggr_type = aggr_tc.target_type
@@ -326,7 +414,11 @@ class Typifier:
f"Aggregate of type {aggr_type} does not have a member {member}."
)
- tc.apply_dtype(expr, member.dtype)
+ member_type = member.dtype
+ if aggr_type.const:
+ member_type = constify(member_type)
+
+ tc.apply_dtype(member_type, expr)
case PsBinOp(op1, op2):
self.visit_expr(op1, tc)
@@ -365,14 +457,14 @@ class Typifier:
f"{len(items)} items as {tc.target_type}"
)
else:
- items_tc.apply_dtype(None, tc.target_type.base_type)
+ items_tc.apply_dtype(tc.target_type.base_type)
else:
arr_type = PsArrayType(items_tc.target_type, len(items))
- tc.apply_dtype(expr, arr_type)
+ tc.apply_dtype(arr_type, expr)
case PsCast(dtype, arg):
self.visit_expr(arg, TypeContext())
- tc.apply_dtype(expr, dtype)
+ tc.apply_dtype(dtype, expr)
case _:
raise NotImplementedError(f"Can't typify {expr}")
diff --git a/tests/nbackend/kernelcreation/test_typification.py b/tests/nbackend/kernelcreation/test_typification.py
index ef746c614901a2a15a3b63e117d0c7cec61b9676..d9cc5f9cef240e923a8d80a7651947b1ca762ff4 100644
--- a/tests/nbackend/kernelcreation/test_typification.py
+++ b/tests/nbackend/kernelcreation/test_typification.py
@@ -6,11 +6,11 @@ from typing import cast
from pystencils import Assignment, TypedSymbol, Field, FieldType
-from pystencils.backend.ast.structural import PsDeclaration
+from pystencils.backend.ast.structural import PsDeclaration, PsAssignment, PsExpression
from pystencils.backend.ast.expressions import PsConstantExpr, PsSymbolExpr, PsBinOp
from pystencils.backend.constants import PsConstant
from pystencils.types import constify
-from pystencils.types.quick import Fp, create_numeric_type
+from pystencils.types.quick import Fp, create_type, create_numeric_type
from pystencils.backend.kernelcreation.context import KernelCreationContext
from pystencils.backend.kernelcreation.freeze import FreezeExpressions
from pystencils.backend.kernelcreation.typification import Typifier, TypificationError
@@ -38,7 +38,7 @@ def test_typify_simple():
assert isinstance(fasm, PsDeclaration)
def check(expr):
- assert expr.dtype == ctx.default_dtype
+ assert expr.dtype == constify(ctx.default_dtype)
match expr:
case PsConstantExpr(cs):
assert cs.value == 2
@@ -56,6 +56,89 @@ def test_typify_simple():
check(fasm.rhs)
+def test_rhs_constness():
+ default_type = Fp(32)
+ ctx = KernelCreationContext(default_dtype=default_type)
+
+ freeze = FreezeExpressions(ctx)
+ typify = Typifier(ctx)
+
+ f = Field.create_generic(
+ "f", 1, index_shape=(1,), dtype=default_type, field_type=FieldType.CUSTOM
+ )
+ f_const = Field.create_generic(
+ "f_const",
+ 1,
+ index_shape=(1,),
+ dtype=constify(default_type),
+ field_type=FieldType.CUSTOM,
+ )
+
+ x, y, z = sp.symbols("x, y, z")
+
+ # Right-hand sides should always get const types
+ asm = typify(freeze(Assignment(x, f.absolute_access([0], [0]))))
+ assert asm.rhs.get_dtype().const
+
+ asm = typify(
+ freeze(
+ Assignment(
+ f.absolute_access([0], [0]),
+ f.absolute_access([0], [0]) * f_const.absolute_access([0], [0]) * x + y,
+ )
+ )
+ )
+ assert asm.rhs.get_dtype().const
+
+
+def test_lhs_constness():
+ default_type = Fp(32)
+ ctx = KernelCreationContext(default_dtype=default_type)
+ freeze = FreezeExpressions(ctx)
+ typify = Typifier(ctx)
+
+ f = Field.create_generic(
+ "f", 1, index_shape=(1,), dtype=default_type, field_type=FieldType.CUSTOM
+ )
+ f_const = Field.create_generic(
+ "f_const",
+ 1,
+ index_shape=(1,),
+ dtype=constify(default_type),
+ field_type=FieldType.CUSTOM,
+ )
+
+ x, y, z = sp.symbols("x, y, z")
+
+ # Assignment RHS may not be const
+ asm = typify(freeze(Assignment(f.absolute_access([0], [0]), x + y)))
+ assert not asm.lhs.get_dtype().const
+
+ # Cannot assign to const left-hand side
+ with pytest.raises(TypificationError):
+ _ = typify(freeze(Assignment(f_const.absolute_access([0], [0]), x + y)))
+
+ np_struct = np.dtype([("size", np.uint32), ("data", np.float32)])
+ struct_type = constify(create_type(np_struct))
+ struct_field = Field.create_generic(
+ "struct_field", 1, dtype=struct_type, field_type=FieldType.CUSTOM
+ )
+
+ with pytest.raises(TypificationError):
+ _ = typify(freeze(Assignment(struct_field.absolute_access([0], "data"), x)))
+
+ # Const LHS is only OK in declarations
+
+ q = ctx.get_symbol("q", Fp(32, const=True))
+ ast = PsDeclaration(PsExpression.make(q), PsExpression.make(q))
+ ast = typify(ast)
+ assert ast.lhs.dtype == Fp(32, const=True)
+
+ ast = PsAssignment(PsExpression.make(q), PsExpression.make(q))
+ with pytest.raises(TypificationError):
+ typify(ast)
+
+
def test_typify_structs():
ctx = KernelCreationContext(default_dtype=Fp(32))
freeze = FreezeExpressions(ctx)
@@ -70,6 +153,10 @@ def test_typify_structs():
fasm = freeze(asm)
fasm = typify(fasm)
+ asm = Assignment(f.absolute_access((0,), "data"), x)
+ fasm = freeze(asm)
+ fasm = typify(fasm)
+
# Bad
asm = Assignment(x, f.absolute_access((0,), "size"))
fasm = freeze(asm)
@@ -87,7 +174,7 @@ def test_contextual_typing():
expr = typify(expr)
def check(expr):
- assert expr.dtype == ctx.default_dtype
+ assert expr.dtype == constify(ctx.default_dtype)
match expr:
case PsConstantExpr(cs):
assert cs.value in (2, 3, -4)
@@ -199,6 +286,6 @@ def test_typify_constant_clones():
expr_clone = expr.clone()
expr = typify(expr)
-
+
assert expr_clone.operand1.dtype is None
assert cast(PsConstantExpr, expr_clone.operand1).constant.dtype is None