optimize: add a dead method removal optimization

Signed-off-by: Jean-Sebastien Gelinas <calestar@gmail.com>
Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/analysis/analysis.nit b/src/analysis/analysis.nit
index bf61eb4..f151f4b 100644 (file)
--- a/src/analysis/analysis.nit
+++ b/src/analysis/analysis.nit
@@ -31,6 +31,13 @@ import inline_methods
 import instantiated_type_analysis
 import reachable_method_analysis
 
+# Global Optimizations
+import dead_method_removal
+
+redef class ToolContext
+       readable writable var _no_dead_method_removal: Bool = false
+end
+
 redef class Program
        # This method will analyse the program and store results (in global compilation only)
        fun do_global_analysis do
@@ -43,6 +50,7 @@ redef class Program
        # This method will optimize the program (in global compilation only)
        fun do_global_optimizations do
                assert tc.global
+               if not tc.no_dead_method_removal then optimize_dead_methods
        end
 end
 

diff --git a/src/analysis/dead_method_removal.nit b/src/analysis/dead_method_removal.nit
new file mode 100644 (file)
index 0000000..4a1a618
--- /dev/null
+++ b/src/analysis/dead_method_removal.nit
@@ -0,0 +1,69 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Copyright 2009 Jean-Sebastien Gelinas <calestar@gmail.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This package introduces an algorithm to remove the body of dead methods
+package dead_method_removal
+
+import reachable_method_analysis
+
+redef class Program
+       # Calling this method will change all iroutines that are dead
+       # and put an abort in them
+       fun optimize_dead_methods do
+               for m in module.mhe.greaters_and_self do
+                       for c in m.local_classes do
+
+                               # Process methods and attributes initialization
+                               for p in c.local_local_properties do
+                                       var iroutine: nullable IRoutine = null
+
+                                       if p isa MMAttribute then
+                                               iroutine = p.iroutine
+                                       else if p isa MMMethod then
+                                               iroutine = p.iroutine
+                                       end
+                                       if iroutine == null then continue
+       
+                                       if not rma.is_iroutine_reachable(iroutine) then
+                                               iroutine.set_not_reachable(m)
+                                       end
+                               end
+
+                               # Process class-specific iroutines
+                               if c.init_var_iroutine != null and not rma.is_iroutine_reachable(c.init_var_iroutine) then
+                                       c.init_var_iroutine.set_not_reachable(m)
+                               end
+                               if c.checknew_iroutine != null and not rma.is_iroutine_reachable(c.checknew_iroutine) then
+                                       c.checknew_iroutine.set_not_reachable(m)
+                               end
+                               for i in c.new_instance_iroutine do
+                                       if not rma.is_iroutine_reachable(i) then
+                                               i.set_not_reachable(m)
+                                       end
+                               end
+                       end
+               end
+       end
+end
+
+redef class IRoutine
+       # Simple helper function ...
+       private fun set_not_reachable(m: MMModule) do
+               var icb = new ICodeBuilder(m, self)
+               icb.seq.icodes.clear
+               icb.add_abort("This method should not be called !")
+       end
+end

diff --git a/src/nitc.nit b/src/nitc.nit
index db466fb..ef35888 100644 (file)
--- a/src/nitc.nit
+++ b/src/nitc.nit
@@ -31,6 +31,7 @@ special AbstractCompiler
        readable var _opt_no_cc: OptionBool = new OptionBool("Do not invoke C compiler", "--no_cc")
        readable var _opt_global: OptionBool = new OptionBool("Use global compilation", "--global")
        readable var _opt_global_no_STF_opt: OptionBool = new OptionBool("Do not use SFT optimization", "--no-global-SFT-optimization")
+       readable var _opt_global_no_DMR_opt: OptionBool = new OptionBool("Do not use dead method removal optimization", "--no-global-DMR-optimization")
        readable var _opt_clibdir: OptionString = new OptionString("NIT C library directory", "--clibdir")
        readable var _opt_bindir: OptionString = new OptionString("NIT tools directory", "--bindir")
        readable var _opt_compdir: OptionString = new OptionString("Intermediate compilation directory", "--compdir")
@@ -40,7 +41,7 @@ special AbstractCompiler
        init
        do
                super("nitc")
-               option_context.add_option(opt_output, opt_boost, opt_no_cc, opt_global, opt_clibdir, opt_bindir, opt_compdir, opt_extension_prefix, opt_dump, opt_global_no_STF_opt)
+               option_context.add_option(opt_output, opt_boost, opt_no_cc, opt_global, opt_clibdir, opt_bindir, opt_compdir, opt_extension_prefix, opt_dump, opt_global_no_STF_opt, opt_global_no_DMR_opt)
        end
 
        redef fun process_options
@@ -53,6 +54,7 @@ special AbstractCompiler
                if ext != null then ext_prefix = ext else ext_prefix = ""
                global = opt_global.value
                use_SFT_optimization = not opt_global_no_STF_opt.value
+               no_dead_method_removal = opt_global_no_DMR_opt.value
                compdir = opt_compdir.value
                if compdir == null then
                        var dir = once ("NIT_COMPDIR".to_symbol).environ