Move ast, xform, and legalize modules.

- cdsl.ast defines classes representing abstract syntax trees.
- cdsl.xform defines classes for instruction transformations.
- base.legalize defines legalization patterns.

lib/cretonne/meta/base/legalize.py

@@ -7,12 +7,12 @@ patterns that describe how base instructions can be transformed to other base
 instructions that are legal.
 """
 from __future__ import absolute_import
-from base.instructions import iadd, iadd_cout, iadd_cin, iadd_carry
-from base.instructions import isub, isub_bin, isub_bout, isub_borrow
-from base.instructions import band, bor, bxor, isplit_lohi, iconcat_lohi
-from base.instructions import icmp
-from .ast import Var
-from .xform import Rtl, XFormGroup
+from .instructions import iadd, iadd_cout, iadd_cin, iadd_carry
+from .instructions import isub, isub_bin, isub_bout, isub_borrow
+from .instructions import band, bor, bxor, isplit_lohi, iconcat_lohi
+from .instructions import icmp
+from cdsl.ast import Var
+from cdsl.xform import Rtl, XFormGroup
 
 
 narrow = XFormGroup('narrow', """

lib/cretonne/meta/cdsl/ast.py

@@ -5,7 +5,7 @@ This module defines classes that can be used to create abstract syntax trees
 for patern matching an rewriting of cretonne instructions.
 """
 from __future__ import absolute_import
-from cdsl import instructions
+from . import instructions
 
 try:
     from typing import Union, Tuple  # noqa

lib/cretonne/meta/cdsl/instructions.py

@@ -259,7 +259,7 @@ class Instruction(object):
         Create an `ast.Apply` AST node representing the application of this
         instruction to the arguments.
         """
-        from cretonne.ast import Apply
+        from .ast import Apply
         return Apply(self, args)
 
 
@@ -312,5 +312,5 @@ class BoundInstruction(object):
         Create an `ast.Apply` AST node representing the application of this
         instruction to the arguments.
         """
-        from cretonne.ast import Apply
+        from .ast import Apply
         return Apply(self, args)

lib/cretonne/meta/cdsl/xform.py

@@ -2,10 +2,11 @@
 Instruction transformations.
 """
 from __future__ import absolute_import
-from .ast import Def, Var, Apply, Expr  # noqa
+from .ast import Def, Var, Apply
 
 try:
     from typing import Union, Iterator, Sequence, Iterable  # noqa
+    from .ast import Expr  # noqa
     DefApply = Union[Def, Apply]
 except ImportError:
     pass

lib/cretonne/meta/gen_legalizer.py

@@ -9,12 +9,12 @@ the input instruction.
 """
 from __future__ import absolute_import
 from srcgen import Formatter
-import cretonne.legalize as legalize
-from cretonne.ast import Def  # noqa
-from cretonne.xform import XForm, XFormGroup  # noqa
+from base import legalize
 
 try:
     from typing import Sequence  # noqa
+    from cdsl.ast import Def  # noqa
+    from cdsl.xform import XForm, XFormGroup  # noqa
 except ImportError:
     pass