Begin using a list of bailouts instead of a singleton in the fast code generator.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index 6ee2246b298d5ed60227348cbba461fee52897a0..f01889d0a13856dfa7a35d445ded0f7158c855a3 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -41,6 +41,37 @@ namespace internal {
 // is constructed based on the resources available at compile-time.
 class CompilationInfo BASE_EMBEDDED {
  public:
+  // Compilation mode.  Either the compiler is used as the primary
+  // compiler and needs to setup everything or the compiler is used as
+  // the secondary compiler for split compilation and has to handle
+  // bailouts.
+  enum Mode {
+    PRIMARY,
+    SECONDARY
+  };
+
+  // A description of the compilation state at a bailout to the secondary
+  // code generator.
+  //
+  // The state is currently simple: there are no parameters or local
+  // variables to worry about ('this' can be found in the stack frame).
+  // There are at most two live values.
+  //
+  // There is a label that should be bound to the beginning of the bailout
+  // stub code.
+  class Bailout : public ZoneObject {
+   public:
+    Bailout(Register left, Register right) : left_(left), right_(right) {}

[fschneider, 2010/02/19 14:47:14]

label_ needs to be initialized here.

+
+    Label* label() { return &label_; }
+
+   private:
+    Register left_;
+    Register right_;
+    Label label_;
+  };
+
+
   // Lazy compilation of a JSFunction.
   CompilationInfo(Handle<JSFunction> closure,
                   int loop_nesting,
@@ -117,9 +148,13 @@ class CompilationInfo BASE_EMBEDDED {
   int loop_nesting() { return loop_nesting_; }
   bool has_receiver() { return !receiver_.is_null(); }
   Handle<Object> receiver() { return receiver_; }
+  List<Bailout*>* bailouts() { return &bailouts_; }
 
-  // Accessors for mutable fields, possibly set by analysis passes with
+  // Accessors for mutable fields (possibly set by analysis passes) with
   // default values given by Initialize.
+  Mode mode() { return mode_; }
+  void set_mode(Mode mode) { mode_ = mode; }
+
   bool has_this_properties() { return has_this_properties_; }
   void set_has_this_properties(bool flag) { has_this_properties_ = flag; }
 
@@ -137,8 +172,19 @@ class CompilationInfo BASE_EMBEDDED {
   // Derived accessors.
   Scope* scope() { return function()->scope(); }
 
+  // Add a bailout with two live values.
+  Label* AddBailout(Register left, Register right) {
+    Bailout* bailout = new Bailout(left, right);
+    bailouts_.Add(bailout);
+    return bailout->label();
+  }
+
+  // Add a bailout with no live values.
+  Label* AddBailout() { return AddBailout(no_reg, no_reg); }
+
  private:
   void Initialize() {
+    mode_ = PRIMARY;
     has_this_properties_ = false;
     has_globals_ = false;
   }
@@ -148,6 +194,7 @@ class CompilationInfo BASE_EMBEDDED {
   Handle<Script> script_;
 
   FunctionLiteral* function_;
+  Mode mode_;
 
   bool is_eval_;
   int loop_nesting_;
@@ -157,6 +204,10 @@ class CompilationInfo BASE_EMBEDDED {
   bool has_this_properties_;
   bool has_globals_;
 
+  // An ordered list of bailout points encountered during fast-path
+  // compilation.
+  List<Bailout*> bailouts_;
+
   DISALLOW_COPY_AND_ASSIGN(CompilationInfo);
 };