Enable Pylint in CI and fix its errors (#311)

* Remove wildcard imports

Use explicit imports rather than wildcards. This is more maintainable.

* Enable Pylint in CI and fix its errors

The main fixes were:

* Specify encoding for all file opens. By default it depends on environment variables which is bad.
* Use `with` to open files. Otherwise they don't necessarily get closed.

There were also a few minor things like using `enumerate`, not using objects as default arguments, etc. In some cases I slightly refactored the code.

chisel_utils.py

@@ -1,10 +1,8 @@
 import logging
 import pprint
 
-from constants import *
-
-# from shared_utils import overlaps, overlap_allowed, extension_overlap_allowed, instruction_overlap_allowed, process_enc_line, same_base_isa, add_segmented_vls_insn, expand_nf_field
-from shared_utils import *
+from constants import causes, csrs, csrs32
+from shared_utils import InstrDict, instr_dict_2_extensions
 
 pp = pprint.PrettyPrinter(indent=2)
 logging.basicConfig(level=logging.INFO, format="%(levelname)s:: %(message)s")
@@ -23,7 +21,6 @@ def make_chisel(instr_dict: InstrDict, spinal_hdl: bool = False):
     if not spinal_hdl:
         extensions = instr_dict_2_extensions(instr_dict)
         for e in extensions:
-            e_instrs = filter(lambda i: instr_dict[i]["extension"][0] == e, instr_dict)
             if "rv64_" in e:
                 e_format = e.replace("rv64_", "").upper() + "64"
             elif "rv32_" in e:
@@ -33,10 +30,11 @@ def make_chisel(instr_dict: InstrDict, spinal_hdl: bool = False):
             else:
                 e_format = e.upper()
             chisel_names += f'  val {e_format+"Type"} = Map(\n'
-            for instr in e_instrs:
-                tmp_instr_name = '"' + instr.upper().replace(".", "_") + '"'
-                chisel_names += f'   {tmp_instr_name:<18s} -> BitPat("b{instr_dict[instr]["encoding"].replace("-","?")}"),\n'
-            chisel_names += f"  )\n"
+            for instr_name, instr in instr_dict.items():
+                if instr["extension"][0] == e:
+                    tmp_instr_name = '"' + instr_name.upper().replace(".", "_") + '"'
+                    chisel_names += f'   {tmp_instr_name:<18s} -> BitPat("b{instr["encoding"].replace("-","?")}"),\n'
+            chisel_names += "  )\n"
 
     for num, name in causes:
         cause_names_str += f'  val {name.lower().replace(" ","_")} = {hex(num)}\n'
@@ -65,12 +63,11 @@ def make_chisel(instr_dict: InstrDict, spinal_hdl: bool = False):
     csr_names_str += """    res.toArray
   }"""
 
-    if spinal_hdl:
-        chisel_file = open("inst.spinalhdl", "w")
-    else:
-        chisel_file = open("inst.chisel", "w")
-    chisel_file.write(
-        f"""
+    with open(
+        "inst.spinalhdl" if spinal_hdl else "inst.chisel", "w", encoding="utf-8"
+    ) as chisel_file:
+        chisel_file.write(
+            f"""
 /* Automatically generated by parse_opcodes */
 object Instructions {{
 {chisel_names}
@@ -82,5 +79,4 @@ object CSRs {{
 {csr_names_str}
 }}
 """
-    )
-    chisel_file.close()
+        )