Add last use data flow information to the fast code generator....

src/fast-codegen.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 410 matching lines @@
 
 
 #define __ ACCESS_MASM(masm())
 
 Handle<Code> FastCodeGenerator::MakeCode(CompilationInfo* info) {
   // Label the AST before calling MakeCodePrologue, so AST node numbers are
   // printed with the AST.
   AstLabeler labeler;
   labeler.Label(info);
 
+  LivenessAnalyzer analyzer;
+  analyzer.Analyze(info->function());
+
   CodeGenerator::MakeCodePrologue(info);
 
   const int kInitialBufferSize = 4 * KB;
   MacroAssembler masm(NULL, kInitialBufferSize);
 
   // Generate the fast-path code.
   FastCodeGenerator fast_cgen(&masm);
   fast_cgen.Generate(info);
   if (fast_cgen.HasStackOverflow()) {
     ASSERT(!Top::has_pending_exception());
@@ skipping 136 matching lines @@
   ASSERT(lookup.IsValid());
   ASSERT(lookup.IsDontDelete());
   Handle<Object> cell(info()->global_object()->GetPropertyCell(&lookup));
 
   // Global variable lookups do not have side effects, so we do not need to
   // emit code if we are in an effect context.
   if (!destination().is(no_reg)) {
     Comment cmnt(masm(), ";; Global");
     if (FLAG_print_ir) {
       SmartPointer<char> name = expr->name()->ToCString();
-      PrintF("%d: t%d = Global(%s)\n", expr->num(), expr->num(), *name);
+      PrintF("%d: t%d = Global(%s)  // last_use = %d\n", expr->num(),
+             expr->num(), *name, expr->var_def()->last_use()->num());
     }
     EmitGlobalVariableLoad(cell);
   }
 }
 
 
 void FastCodeGenerator::VisitLiteral(Literal* expr) {
   UNREACHABLE();
 }
 
@@ skipping 33 matching lines @@
   ASSERT(prop->obj()->AsVariableProxy()->var()->is_this());
   ASSERT(prop->key()->IsPropertyName());
   Handle<String> name =
       Handle<String>::cast(prop->key()->AsLiteral()->handle());
 
   Comment cmnt(masm(), ";; Store to this");
   if (FLAG_print_ir) {
     SmartPointer<char> name_string = name->ToCString();
     PrintF("%d: ", expr->num());
     if (!destination().is(no_reg)) PrintF("t%d = ", expr->num());
-    PrintF("Store(this, \"%s\", t%d)\n", *name_string, expr->value()->num());
+    PrintF("Store(this, \"%s\", t%d)  // last_use(this) = %d\n", *name_string,
+           expr->value()->num(),
+           expr->var_def()->last_use()->num());
   }
 
   EmitThisPropertyStore(name);
 }
 
 
 void FastCodeGenerator::VisitThrow(Throw* expr) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitProperty(Property* expr) {
   ASSERT_NOT_NULL(expr->obj()->AsVariableProxy());
   ASSERT(expr->obj()->AsVariableProxy()->var()->is_this());
   ASSERT(expr->key()->IsPropertyName());
   if (!destination().is(no_reg)) {
     Handle<String> name =
         Handle<String>::cast(expr->key()->AsLiteral()->handle());
 
     Comment cmnt(masm(), ";; Load from this");
     if (FLAG_print_ir) {
       SmartPointer<char> name_string = name->ToCString();
-      PrintF("%d: t%d = Load(this, \"%s\")\n",
-             expr->num(), expr->num(), *name_string);
+      PrintF("%d: t%d = Load(this, \"%s\")  // last_use(this) = %d\n",
+             expr->num(), expr->num(), *name_string,
+             expr->var_def()->last_use()->num());
     }
     EmitThisPropertyLoad(name);
   }
 }
 
 
 void FastCodeGenerator::VisitCall(Call* expr) {
   UNREACHABLE();
 }
 
@@ skipping 48 matching lines @@
 
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   UNREACHABLE();
 }
 
 #undef __
 
 
 } }  // namespace v8::internal