Merge pull request myhdl#160 from MrCanadianMenace/name_collision_fix

[RDY] Name collision fix (Issue myhdl#95)

.gitignore

@@ -33,3 +33,6 @@ work_vcom/
 # Test artifacts
 myhdl/**/*.v
 myhdl/**/*.vhd
+
+# Pycharm ide junk
+.idea/

myhdl/conversion/_VHDLNameValidation.py

@@ -0,0 +1,47 @@
+import warnings
+from myhdl import *
+from myhdl import ToVHDLWarning
+from myhdl.conversion import _analyze
+import pytest
+
+#A list of all reserved words within VHDL which should not be used for
+#anything other than their own specific purpose
+_vhdl_keywords = ["abs", "access", "after", "alias", "all",
+              "and", "architecture", "array", "assert",
+              "attribute", "begin", "block", "body", "buffer",
+              "bus", "case", "component", "configuration",
+              "constant", "disconnect", "downto", "else",
+              "elseif", "end", "entity", "exit", "file", "for",
+              "function", "generate", "generic", "group",
+              "guarded", "if", "impure", "in", "inertial",
+              "inout", "is", "label", "library", "linkage",
+              "literal", "loop", "map", "mod", "nand", "new",
+              "next", "nor", "not", "null", "of", "on", "open",
+              "or", "others", "out", "package", "port",
+              "postponed", "procedure", "process", "pure",
+              "range", "record", "register", "reject", "rem",
+              "report", "return", "rol", "ror", "select",
+              "severity", "signal", "shared", "sla", "sll", "sra",
+              "srl", "subtype", "then", "to", "transport", "type",
+              "unaffected", "units", "until", "use", "variable",
+              "wait", "when", "while", "with", "xnor", "xor"];
+
+#A list to hold all signal names being used in lowercase to raise an error
+#if no names are reused with different casing
+_usedNames = [];
+
+#Function which compares current parsed signal/entity to all keywords to
+#ensure reserved words are not being used for the wrong purpose
+def _nameValid(name):
+    for keyword in _vhdl_keywords:
+        if name == keyword:
+            warnings.warn("VHDL keyword used: %s" % (name), category=ToVHDLWarning)
+    for saved_name in _usedNames:
+        if name.lower() == saved_name:
+            warnings.warn("Previously used name being reused: %s" % (name), category=ToVHDLWarning)
+    _usedNames.append(name.lower())
+    if name[0] == '_':
+        warnings.warn("VHDL variable names cannot contain '_': %s" % (name), category=ToVHDLWarning)
+    for char in name:
+        if char == '-':
+            warnings.warn("VHDL variable names cannot contain '-': %s" % (name), category=ToVHDLWarning)

myhdl/conversion/_toVHDL.py

@@ -55,6 +55,8 @@
 from myhdl._util import _flatten
 from myhdl._compat import integer_types, class_types, StringIO
 from myhdl._ShadowSignal import _TristateSignal, _TristateDriver
+from myhdl.conversion._VHDLNameValidation import _nameValid
+
 
 from myhdl._block import _Block
 from myhdl._getHierarchy import _getHierarchy
@@ -353,6 +355,8 @@ def _writeModuleHeader(f, intf, needPck, lib, arch, useClauses, doc, stdLogicPor
             pt = st = _getTypeString(s)
             if convertPort:
                 pt = "std_logic_vector"
+             # Check if VHDL keyword or reused name
+            _nameValid(s._name)
             if s._driven:
                 if s._read:
                     if not isinstance(s, _TristateSignal):
@@ -439,6 +443,8 @@ def _writeSigDecls(f, intf, siglist, memlist):
             print("signal %s: %s%s%s;" % (s._name, p, r, val_str), file=f)
 
         elif s._read:
+            # Check if VHDL keyword or reused name
+            _nameValid(s._name)
             # the original exception
             # raise ToVHDLError(_error.UndrivenSignal, s._name)
             # changed to a warning and a continuous assignment to a wire
@@ -458,6 +464,8 @@ def _writeSigDecls(f, intf, siglist, memlist):
                 m._read = s._read
         if not m._driven and not m._read:
             continue
+        # Check if VHDL keyword or reused name
+        _nameValid(m.name)
         r = _getRangeString(m.elObj)
         p = _getTypeString(m.elObj)
         t = "t_array_%s" % m.name