Pass control command line options.

It turns out that --enable-collapse is fundamentally misguided. We'll
need a better solution for that. --no-branch-extension looks pretty good.

src/Ophis/CmdLine.py

@@ -6,7 +6,6 @@ import optparse
 # You may use, modify, and distribute this file under the MIT
 # license: See README for details.
 
-enable_collapse = True
 enable_branch_extend = True
 enable_undoc_ops = False
 enable_65c02_exts = False
@@ -56,9 +55,6 @@ def parse_args(raw_args):
                       default=True, help="Do not print warnings")
 
     bingrp = optparse.OptionGroup(parser, "Compilation options")
-    bingrp.add_option("--no-collapse", action="store_false",
-                      dest="enable_collapse", default="True",
-                      help="Disable zero-page collapse pass")
     bingrp.add_option("--no-branch-extend", action="store_false",
                       dest="enable_branch_extend", default="True",
                       help="Disable branch-extension pass")
@@ -76,7 +72,6 @@ def parse_args(raw_args):
 
     infiles = args
     outfile = options.outfile
-    enable_collapse = options.enable_collapse
     enable_branch_extend = options.enable_branch_extend
     enable_undoc_ops = options.undoc
     enable_65c02_exts = options.c02

src/Ophis/Main.py

@@ -29,10 +29,20 @@ def run_all():
     l_basic = Ophis.Passes.UpdateLabels()
     l = Ophis.Passes.FixPoint("label update", [l_basic],
                               lambda: not l_basic.changed)
+
+    # The instruction selector is a bunch of fixpoints, and which
+    # passes run depends on the command line options a bit.
     c_basic = Ophis.Passes.Collapse()
     c = Ophis.Passes.FixPoint("instruction selection 1", [l, c_basic],
                               lambda: not c_basic.changed)
-    b = Ophis.Passes.ExtendBranches()
+
+    if Ophis.CmdLine.enable_branch_extend:
+        b = Ophis.Passes.ExtendBranches()
+        instruction_select = Ophis.Passes.FixPoint("instruction selection 2",
+                                                   [c, b],
+                                                   lambda: not b.changed)
+    else:
+        instruction_select = c
     a = Ophis.Passes.Assembler()
 
     passes = []
@@ -44,8 +54,7 @@ def run_all():
     passes.extend([Ophis.Passes.CircularityCheck(),
                    Ophis.Passes.CheckExprs(),
                    Ophis.Passes.EasyModes()])
-    passes.append(Ophis.Passes.FixPoint("instruction selection 2", [c, b],
-                                        lambda: not b.changed))
+    passes.append(instruction_select)
     passes.extend([Ophis.Passes.NormalizeModes(),
                    Ophis.Passes.UpdateLabels(),
                    a])