Python 3 compat.

Try to keep our Python sources compatible with both Python 2.7 and 3.

Check with 'pylint --py3k' and 'python -3'.

meta/isa/__init__.py

@@ -5,7 +5,7 @@ Cretonne target ISA definitions
 The :py:mod:`isa` package contains sub-packages for each target instruction set
 architecture supported by Cretonne.
 """
-
+from __future__ import absolute_import
 from . import riscv
 
 

meta/isa/riscv/__init__.py

@@ -24,10 +24,10 @@ RV32G / RV64G
     F, and D instruction sets listed above.
 
 """
-
-import defs
-import encodings
-import settings
+from __future__ import absolute_import
+from . import defs
+from . import encodings
+from . import settings
 
 # Re-export the primary target ISA definition.
 isa = defs.isa

meta/isa/riscv/defs.py

@@ -3,7 +3,7 @@ RISC-V definitions.
 
 Commonly used definitions.
 """
-
+from __future__ import absolute_import
 from cretonne import TargetISA, CPUMode
 import cretonne.base
 

meta/isa/riscv/encodings.py

@@ -1,9 +1,10 @@
 """
 RISC-V Encodings.
 """
+from __future__ import absolute_import
 from cretonne import base
-from defs import RV32, RV64
-from recipes import OPIMM, OPIMM32, OP, OP32, R, Rshamt
+from .defs import RV32, RV64
+from .recipes import OPIMM, OPIMM32, OP, OP32, R, Rshamt
 
 # Basic arithmetic binary instructions are encoded in an R-type instruction.
 for inst,           f3,    f7 in [

meta/isa/riscv/recipes.py

@@ -8,6 +8,7 @@ instruction formats described in the reference:
     Volume I: User-Level ISA
     Version 2.1
 """
+from __future__ import absolute_import
 from cretonne import EncRecipe
 from cretonne.formats import Binary, BinaryImm
 

meta/isa/riscv/settings.py

@@ -1,11 +1,11 @@
 """
 RISC-V settings.
 """
-
+from __future__ import absolute_import
 from cretonne import SettingGroup, BoolSetting
 from cretonne.predicates import And
 import cretonne.settings as shared
-from defs import isa
+from .defs import isa
 
 isa.settings = SettingGroup('riscv', parent=shared.group)