Implement --prune-unreachable-routines.

HISTORY.md

@@ -11,6 +11,9 @@ History of SixtyPical
 *   A routine can be declared `preserved`, which prevents a
     compiler from omitting it from the final executable, even
     if it determines it is not called by any other routine.
+*   Added `--prune-unreachable-routines` option, which causes
+    the compiler to in fact omit routines determined to be
+    unreachable as described above.
 *   The `dcc6502-adapter` test adapter was updated to conform
     to the output of the latest version of `dcc6502`.
 

TODO.md

@@ -95,13 +95,6 @@ As long as the routine has consistent type context every place it exits, that sh
 Currently the `if` generator is not smart enough to avoid generating silly
 jump instructions.  (See the Fallthru tests.)  Improve it.
 
-### Dead code removal
-
-Once we have a call graph we can omit routines that we're sure aren't called.
-
-This would let us use include-files and standard-libraries nicely: any
-routines they define, but that you don't use, don't get included.
-
 Implementation
 --------------
 
@@ -110,6 +103,11 @@ Implementation
 For analysis errors, there is a line number, but it's the line of the routine
 after the routine in which the analysis error occurred.  Fix this.
 
+### Libraries
+
+Now that we have dead-code removal, establish some libraries of reusable
+routines.
+
 Blue-skying
 -----------
 

bin/sixtypical

@@ -19,6 +19,7 @@ import traceback
 from sixtypical.symtab import SymbolTable
 from sixtypical.parser import Parser, merge_programs
 from sixtypical.analyzer import Analyzer
+from sixtypical.callgraph import construct_callgraph, prune_unreachable_routines
 from sixtypical.outputter import outputter_class_for
 from sixtypical.compiler import Compiler
 
@@ -47,13 +48,14 @@ def process_input_files(filenames, options):
         analyzer.analyze_program(program)
     finally:
         if options.dump_exit_contexts:
-            sys.stdout.write(json.dumps(analyzer.exit_contexts_map, indent=4, sort_keys=True, separators=(',', ':')))
+            sys.stdout.write(json.dumps(analyzer.exit_contexts_map, indent=4, sort_keys=True, separators=(',', ': ')))
             sys.stdout.write("\n")
 
+    callgraph = construct_callgraph(program)
     if options.dump_callgraph:
-        from sixtypical.callgraph import construct_callgraph
-        graph = construct_callgraph(program)
-        sys.stdout.write(json.dumps(graph, indent=4, sort_keys=True, separators=(',', ': ')))
+        sys.stdout.write(json.dumps(callgraph, indent=4, sort_keys=True, separators=(',', ': ')))
+    if options.prune_unreachable_routines:
+        program = prune_unreachable_routines(program, callgraph)
 
     compilation_roster = None
     if options.optimize_fallthru:
@@ -166,6 +168,12 @@ if __name__ == '__main__':
         action="store_true",
         help="Dump the ordered fallthru map, in JSON, to stdout after analyzing the program."
     )
+    argparser.add_argument(
+        "--prune-unreachable-routines",
+        action="store_true",
+        help="Omit code for unreachable routines (as determined by the callgraph) "
+             "from the final output."
+    )
     argparser.add_argument(
         "--dump-callgraph",
         action="store_true",

src/sixtypical/callgraph.py

@@ -1,3 +1,4 @@
+from sixtypical.ast import Program
 from sixtypical.model import RoutineType, VectorType
 
 
@@ -58,3 +59,9 @@ def construct_callgraph(program):
         mark_as_reachable(graph, routine.name)
 
     return graph
+
+
+def prune_unreachable_routines(program, callgraph):
+    return Program(1, defns=program.defns, routines=[
+        r for r in program.routines if callgraph[r.name].get('reachable', False)
+    ])

tests/SixtyPical Callgraph.md

@@ -183,3 +183,41 @@ reachable.
     =         ]
     =     }
     = }
+
+    -> Tests for functionality "Compile SixtyPical program with unreachable routine removal"
+
+Basic test for actually removing unreachable routines from the resulting
+executable when compiling SixtyPical programs.
+
+    | define main routine outputs a trashes z, n
+    | {
+    |   ld a, 100
+    | }
+    | 
+    | define other1 routine
+    | {
+    |   call other2
+    | }
+    | 
+    | define other2 routine
+    | {
+    |   call other1
+    | }
+    = $080D   LDA #$64
+    = $080F   RTS
+
+Test that marking routine as `preserved` preserves it in the output.
+
+    | define main routine outputs a trashes z, n
+    | {
+    |   ld a, 100
+    | }
+    | 
+    | define other preserved routine outputs a trashes z, n
+    | {
+    |   ld a, 5
+    | }
+    = $080D   LDA #$64
+    = $080F   RTS
+    = $0810   LDA #$05
+    = $0812   RTS

tests/appliances/sixtypical.md

@@ -13,11 +13,14 @@ implementation, `sixtypical`, that is going to implement these functionalities.
     -> Functionality "Compile SixtyPical program" is implemented by
     -> shell command "bin/sixtypical --output-format=c64-basic-prg --traceback %(test-body-file) --output /tmp/foo && tests/appliances/bin/dcc6502-adapter </tmp/foo"
 
-    -> Functionality "Dump fallthru info for SixtyPical program" is implemented by
-    -> shell command "bin/sixtypical --optimize-fallthru --dump-fallthru-info --analyze-only --traceback %(test-body-file)"
-
     -> Functionality "Dump callgraph info for SixtyPical program" is implemented by
     -> shell command "bin/sixtypical --dump-callgraph --analyze-only --traceback %(test-body-file)"
 
+    -> Functionality "Compile SixtyPical program with unreachable routine removal" is implemented by
+    -> shell command "bin/sixtypical --output-format=c64-basic-prg --prune-unreachable-routines --traceback %(test-body-file) --output /tmp/foo && tests/appliances/bin/dcc6502-adapter </tmp/foo"
+
+    -> Functionality "Dump fallthru info for SixtyPical program" is implemented by
+    -> shell command "bin/sixtypical --optimize-fallthru --dump-fallthru-info --analyze-only --traceback %(test-body-file)"
+
     -> Functionality "Compile SixtyPical program with fallthru optimization" is implemented by
     -> shell command "bin/sixtypical --output-format=c64-basic-prg --optimize-fallthru --traceback %(test-body-file) --output /tmp/foo && tests/appliances/bin/dcc6502-adapter </tmp/foo"