Refactor the handling of generations in the compilation cache.

Add generations to the compilation cache for eval and regexp. The number of generations for these are set to two.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/140056

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2233 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/compilation-cache.h

@@ -34,20 +34,9 @@ namespace internal {
 
 // The compilation cache keeps function boilerplates for compiled
 // scripts and evals. The boilerplates are looked up using the source
-// string as the key.
+// string as the key. For regular expressions the compilation data is cached.
 class CompilationCache {
  public:
-  // The same source code string has different compiled code for
-  // scripts and evals. Internally, we use separate caches to avoid
-  // getting the wrong kind of entry when looking up.
-  enum Entry {
-    EVAL_GLOBAL,
-    EVAL_CONTEXTUAL,
-    REGEXP,
-    SCRIPT,
-    LAST_ENTRY = SCRIPT
-  };
-
   // Finds the script function boilerplate for a source
   // string. Returns an empty handle if the cache doesn't contain a
   // script for the given source string with the right origin.
@@ -61,7 +50,7 @@ class CompilationCache {
   // contain a script for the given source string.
   static Handle<JSFunction> LookupEval(Handle<String> source,
                                        Handle<Context> context,
-                                       Entry entry);
+                                       bool is_global);
 
   // Returns the regexp data associated with the given regexp if it
   // is in cache, otherwise an empty handle.
@@ -77,7 +66,7 @@ class CompilationCache {
   // with the boilerplate. This may overwrite an existing mapping.
   static void PutEval(Handle<String> source,
                       Handle<Context> context,
-                      Entry entry,
+                      bool is_global,
                       Handle<JSFunction> boilerplate);
 
   // Associate the (source, flags) pair to the given regexp data.

src/compiler.cc

@@ -295,14 +295,11 @@ Handle<JSFunction> Compiler::CompileEval(Handle<String> source,
 
   // The VM is in the COMPILER state until exiting this function.
   VMState state(COMPILER);
-  CompilationCache::Entry entry = is_global
-      ? CompilationCache::EVAL_GLOBAL
-      : CompilationCache::EVAL_CONTEXTUAL;
 
   // Do a lookup in the compilation cache; if the entry is not there,
   // invoke the compiler and add the result to the cache.
   Handle<JSFunction> result =
-      CompilationCache::LookupEval(source, context, entry);
+      CompilationCache::LookupEval(source, context, is_global);
   if (result.is_null()) {
     // Create a script object describing the script to be compiled.
     Handle<Script> script = Factory::NewScript(source);
@@ -314,7 +311,7 @@ Handle<JSFunction> Compiler::CompileEval(Handle<String> source,
                           NULL,
                           NULL);
     if (!result.is_null()) {
-      CompilationCache::PutEval(source, context, entry, result);
+      CompilationCache::PutEval(source, context, is_global, result);
     }
   }