From da3557df665398a589cf4b3c1a11a79aa590f4da Mon Sep 17 00:00:00 2001
From: Peter Zotov <whitequark@whitequark.org>
Date: Sat, 14 Apr 2012 10:36:27 +0400
Subject: [PATCH] Implement global variables.

---
 lib/furnace-avm2/abc/metadata/script_info.rb  |  1 +
 .../source/declaration_tokens/script_token.rb |  2 +-
 lib/furnace-avm2/source/decompiler.rb         | 71 ++++++++++++++-----
 test/global.as                                | 11 +++
 4 files changed, 67 insertions(+), 18 deletions(-)
 create mode 100644 test/global.as

diff --git a/lib/furnace-avm2/abc/metadata/script_info.rb b/lib/furnace-avm2/abc/metadata/script_info.rb
index c305e69..23a2e88 100644
--- a/lib/furnace-avm2/abc/metadata/script_info.rb
+++ b/lib/furnace-avm2/abc/metadata/script_info.rb
@@ -1,6 +1,7 @@
 module Furnace::AVM2::ABC
   class ScriptInfo < Record
     include InitializerBody
+    include RecordWithTraits
 
     root_ref     :initializer,  :method
 
diff --git a/lib/furnace-avm2/source/declaration_tokens/script_token.rb b/lib/furnace-avm2/source/declaration_tokens/script_token.rb
index 15bcb56..4f7eb30 100644
--- a/lib/furnace-avm2/source/declaration_tokens/script_token.rb
+++ b/lib/furnace-avm2/source/declaration_tokens/script_token.rb
@@ -3,7 +3,7 @@ class ScriptToken < Furnace::Code::NonterminalToken
     include TokenWithTraits
 
     def initialize(origin, options={})
-      options = options.merge(environment: :script)
+      options = options.merge(environment: :script, global_context: origin)
 
       super(origin, [
         *transform_traits(origin, options.merge(static: false)),
diff --git a/lib/furnace-avm2/source/decompiler.rb b/lib/furnace-avm2/source/decompiler.rb
index 622fcd1..029a632 100644
--- a/lib/furnace-avm2/source/decompiler.rb
+++ b/lib/furnace-avm2/source/decompiler.rb
@@ -46,19 +46,13 @@ def decompile
         @nf = @body.code_to_nf
 
         if captures = ActivationPrologue.match(@nf)
-          @has_closure = true
-          @activation_local = captures[:activation_local]
-
-          @slots = {}
-          @body.traits.map do |trait|
-            @slots[trait.idx] = trait
+          @closure_slots = {}
+          @body.slot_traits.each do |trait|
+            @closure_slots[trait.idx] = trait
           end
 
           @nf.children.slice! 0...4
         else
-          @has_closure = false
-          @activation_local = nil
-
           if RegularPrologue.match @nf
             @nf.children.slice! 0...1
           else
@@ -66,6 +60,13 @@ def decompile
           end
         end
 
+        if global = @options[:global_context]
+          @global_slots = {}
+          global.slot_traits.each do |trait|
+            @global_slots[trait.idx] = trait
+          end
+        end
+
         stmt_block @nf, function: true
 
       rescue Exception => e
@@ -312,10 +313,24 @@ def expr_get_local(opcode)
         [:get_scope_object, 1]]
     end
 
+    GlobalGetSlot = Matcher.new do
+      [:get_slot,
+        capture(:index),
+        either[
+          [:get_global_scope],    # normalized form
+          [:get_scope_object, 0]  # not emitted by ASC
+        ]]
+    end
+
     def expr_get_slot(opcode)
-      if @has_closure && captures = ActivationGetSlot.match(opcode)
-        index, = captures.values_at(:index)
-        token(VariableNameToken, @slots[index].name.name)
+      if @closure_slots && captures = ActivationGetSlot.match(opcode)
+        # treat as a local variable
+        slot = @closure_slots[captures[:index]]
+        token(VariableNameToken)
+      elsif @global_slots && captures = GlobalGetSlot.match(opcode)
+        # treat as a global property
+        slot = @global_slots[captures[:index]]
+        get_name(nil, slot.name.to_astlet)
       end
     end
 
@@ -393,16 +408,38 @@ def expr_set_local(opcode)
         capture(:value)]
     end
 
+    GlobalSetSlot = Matcher.new do
+      [:set_slot,
+        capture(:index),
+        either[
+          [:get_global_scope],    # normalized form
+          [:get_scope_object, 0]  # not emitted by ASC
+        ],
+        capture(:value)]
+    end
+
     def expr_set_slot(opcode)
-      if @has_closure && captures = ActivationSetSlot.match(opcode)
+      if @closure_slots && captures = ActivationSetSlot.match(opcode)
+        # treat as a local variable
         index, value = captures.values_at(:index, :value)
+        slot = @closure_slots[index]
 
-        type = type_token(@slots[index].type.to_astlet)
-        expr_set_var(@slots[index].name.name, value, type,
+        type = type_token(slot.type.to_astlet)
+        expr = expr_set_var(slot.name.name, value, type,
               !@locals.include?(index))
+        @locals.add index
+
+        expr
+      elsif @global_slots && captures = GlobalSetSlot.match(opcode)
+        # treat as a global property
+        index, value = captures.values_at(:index, :value)
+        slot = @global_slots[index]
+
+        token(AssignmentToken, [
+          get_name(nil, slot.name.to_astlet),
+          expr(value)
+        ])
       end
-    ensure
-      @locals.add index if index
     end
 
     ## Arithmetics
diff --git a/test/global.as b/test/global.as
new file mode 100644
index 0000000..2621f77
--- /dev/null
+++ b/test/global.as
@@ -0,0 +1,11 @@
+package global {
+  var a:int = 0;
+
+  function q() {
+    print("a value is: " + a);
+  }
+
+  a = 10;
+
+  q();
+}
\ No newline at end of file