Implement new support for if statements in top-level code.

src/fast-codegen.cc

 // Copyright 2009 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 271 matching lines @@
 }
 
 
 void FastCodeGenerator::VisitEmptyStatement(EmptyStatement* stmt) {
   Comment cmnt(masm_, "[ EmptyStatement");
   SetStatementPosition(stmt);
 }
 
 
 void FastCodeGenerator::VisitIfStatement(IfStatement* stmt) {
-  UNREACHABLE();
+  // Expressions cannot recursively enter statements, there are no labels in
+  // the state.
+  ASSERT_EQ(NULL, true_label_);
+  ASSERT_EQ(NULL, false_label_);
+  Label then_part, else_part, done;
+
+  // Do not worry about optimizing for empty then or else bodies.
+  true_label_ = &then_part;
+  false_label_ = &else_part;
+  Visit(stmt->condition());
+  true_label_ = NULL;
+  false_label_ = NULL;
+
+  __ bind(&then_part);
+  Visit(stmt->then_statement());
+  __ jmp(&done);
+
+  __ bind(&else_part);
+  Visit(stmt->else_statement());
+
+  __ bind(&done);
 }
 
 
 void FastCodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
   UNREACHABLE();
 }
 
 
 void FastCodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
   UNREACHABLE();
@@ skipping 94 matching lines @@
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   UNREACHABLE();
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal