Use optimized code map to cache OSR code.

src/runtime.cc

 // Copyright 2012 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 8662 matching lines @@
   ASSERT(unoptimized->contains(frame->pc()));
 
   ASSERT(pc_offset ==
          static_cast<uint32_t>(frame->pc() - unoptimized->instruction_start()));
 #endif  // DEBUG
 
   // We're not prepared to handle a function with arguments object.
   ASSERT(!function->shared()->uses_arguments());
 
   Handle<Code> result = Handle<Code>::null();
-  BailoutId ast_id = BailoutId::None();
+  BailoutId ast_id = unoptimized->TranslatePcOffsetToAstId(pc_offset);
+  ASSERT(!ast_id.IsNone());
 
-  if (isolate->concurrent_osr_enabled()) {
+  int cached_index = function->shared()->SearchOptimizedCodeMap(
+      function->context()->native_context(), ast_id);
+  if (cached_index != -1) {
+    if (FLAG_trace_osr) {
+      PrintF("[OSR - found cached code for ");
+      function->PrintName();
+      PrintF(" with OSR ast id %d]\n", ast_id.ToInt());
+    }
+    // TODO(titzer): don't install the OSR code into the function.
+    function->shared()->InstallFromOptimizedCodeMap(*function, cached_index);

[Toon Verwaest, 2013/12/04 13:06:25]

I'd prefer to have a single choke-point that sets up the function for OSR, that
would be used from both newly OSRd functions and functions OSRd using cached
code. That way it'll be easier to find this place, to change it so that it
doesn't install the OSR code into the function.

+    result = Handle<Code>(function->code());
+  } else if (isolate->concurrent_osr_enabled()) {
     if (isolate->optimizing_compiler_thread()->
-            IsQueuedForOSR(function, pc_offset)) {
+            IsQueuedForOSR(function, ast_id)) {
       // Still waiting for the optimizing compiler thread to finish.  Carry on.
       if (FLAG_trace_osr) {
         PrintF("[COSR - polling recompile tasks for ");
         function->PrintName();
         PrintF("]\n");
       }
       return NULL;
     }
 
     RecompileJob* job = isolate->optimizing_compiler_thread()->
-        FindReadyOSRCandidate(function, pc_offset);
+        FindReadyOSRCandidate(function, ast_id);
 
     if (job == NULL) {
       if (IsSuitableForOnStackReplacement(isolate, function, unoptimized) &&
-          Compiler::RecompileConcurrent(function, pc_offset)) {
+          Compiler::RecompileConcurrent(function, ast_id)) {
         if (function->IsMarkedForLazyRecompilation() ||
             function->IsMarkedForConcurrentRecompilation()) {
           // Prevent regular recompilation if we queue this for OSR.
           // TODO(yangguo): remove this as soon as OSR becomes one-shot.
           function->ReplaceCode(*unoptimized);
         }
         return NULL;
       }
       // Fall through to the end in case of failure.
     } else {
       // TODO(titzer): don't install the OSR code into the function.
       ast_id = job->info()->osr_ast_id();
       result = Compiler::InstallOptimizedCode(job);
     }
   } else if (IsSuitableForOnStackReplacement(isolate, function, unoptimized)) {
-    ast_id = unoptimized->TranslatePcOffsetToAstId(pc_offset);
-    ASSERT(!ast_id.IsNone());
     if (FLAG_trace_osr) {
       PrintF("[OSR - replacing at AST id %d in ", ast_id.ToInt());
       function->PrintName();
       PrintF("]\n");
     }
     // Attempt OSR compilation.
     result = JSFunction::CompileOsr(function, ast_id, CLEAR_EXCEPTION);
   }
 
   // Revert the patched back edge table, regardless of whether OSR succeeds.
@@ skipping 6185 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal