Introduce concurrent on-stack replacement.

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 8319 matching lines @@
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ConcurrentRecompile) {
   HandleScope handle_scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   if (!AllowOptimization(isolate, function)) {
     function->ReplaceCode(function->shared()->code());
     return isolate->heap()->undefined_value();
   }
   function->shared()->code()->set_profiler_ticks(0);
   ASSERT(FLAG_concurrent_recompilation);
-  Compiler::RecompileConcurrent(function);
+  if (!Compiler::RecompileConcurrent(function)) {
+    function->ReplaceCode(function->shared()->code());
+  }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_InstallRecompiledCode) {
   HandleScope handle_scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   ASSERT(V8::UseCrankshaft() && FLAG_concurrent_recompilation);
   isolate->optimizing_compiler_thread()->InstallOptimizedFunctions();
@@ skipping 148 matching lines @@
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
 
   if (!function->IsOptimizable()) return isolate->heap()->undefined_value();
   function->MarkForLazyRecompilation();
 
   Code* unoptimized = function->shared()->code();
   if (args.length() == 2 &&
       unoptimized->kind() == Code::FUNCTION) {
     CONVERT_ARG_HANDLE_CHECKED(String, type, 1);
     if (type->IsOneByteEqualTo(STATIC_ASCII_VECTOR("osr"))) {
-      for (int i = 0; i <= Code::kMaxLoopNestingMarker; i++) {
+      // Start patching from the currently patched loop nesting level.
+      int current_level = unoptimized->allow_osr_at_loop_nesting_level();
+      ASSERT(Deoptimizer::VerifyInterruptCode(
+                 isolate, unoptimized, current_level));
+      for (int i = current_level + 1; i <= Code::kMaxLoopNestingMarker; i++) {
         unoptimized->set_allow_osr_at_loop_nesting_level(i);
         isolate->runtime_profiler()->AttemptOnStackReplacement(*function);
       }
     } else if (type->IsOneByteEqualTo(STATIC_ASCII_VECTOR("concurrent"))) {
       function->MarkForConcurrentRecompilation();
     }
   }
 
   return isolate->heap()->undefined_value();
 }
@@ skipping 53 matching lines @@
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CompileForOnStackReplacement) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
 
   // We're not prepared to handle a function with arguments object.
   ASSERT(!function->shared()->uses_arguments());
 
-  // We have hit a back edge in an unoptimized frame for a function that was
-  // selected for on-stack replacement.  Find the unoptimized code object.
-  Handle<Code> unoptimized(function->shared()->code(), isolate);
-  // Keep track of whether we've succeeded in optimizing.
-  bool succeeded = unoptimized->optimizable();
-  if (succeeded) {
-    // If we are trying to do OSR when there are already optimized
-    // activations of the function, it means (a) the function is directly or
-    // indirectly recursive and (b) an optimized invocation has been
-    // deoptimized so that we are currently in an unoptimized activation.
-    // Check for optimized activations of this function.
-    JavaScriptFrameIterator it(isolate);
-    while (succeeded && !it.done()) {
-      JavaScriptFrame* frame = it.frame();
-      succeeded = !frame->is_optimized() || frame->function() != *function;
-      it.Advance();
-    }
-  }
-
-  BailoutId ast_id = BailoutId::None();
-  if (succeeded) {
-    // The top JS function is this one, the PC is somewhere in the
-    // unoptimized code.
-    JavaScriptFrameIterator it(isolate);
-    JavaScriptFrame* frame = it.frame();
-    ASSERT(frame->function() == *function);
-    ASSERT(frame->LookupCode() == *unoptimized);
-    ASSERT(unoptimized->contains(frame->pc()));
-
-    // Use linear search of the unoptimized code's back edge table to find
-    // the AST id matching the PC.
-    uint32_t target_pc_offset =
-      static_cast<uint32_t>(frame->pc() - unoptimized->instruction_start());
-    uint32_t loop_depth = 0;
-
-    for (FullCodeGenerator::BackEdgeTableIterator back_edges(*unoptimized);
-         !back_edges.Done();
-         back_edges.Next()) {
-      if (back_edges.pc_offset() == target_pc_offset) {
-        ast_id = back_edges.ast_id();
-        loop_depth = back_edges.loop_depth();
-        break;
-      }
-    }
-    ASSERT(!ast_id.IsNone());
-
-    if (FLAG_trace_osr) {
-      PrintF("[replacing on-stack at AST id %d, loop depth %d in ",
-              ast_id.ToInt(), loop_depth);
-      function->PrintName();
-      PrintF("]\n");
-    }
-
-    // Try to compile the optimized code.  A true return value from
-    // CompileOptimized means that compilation succeeded, not necessarily
-    // that optimization succeeded.
-    if (JSFunction::CompileOptimized(function, ast_id, CLEAR_EXCEPTION) &&
-        function->IsOptimized()) {
-      DeoptimizationInputData* data = DeoptimizationInputData::cast(
-          function->code()->deoptimization_data());
-      if (data->OsrPcOffset()->value() >= 0) {
-        if (FLAG_trace_osr) {
-          PrintF("[on-stack replacement offset %d in optimized code]\n",
-               data->OsrPcOffset()->value());
-        }
-        ASSERT(BailoutId(data->OsrAstId()->value()) == ast_id);
-      } else {
-        // We may never generate the desired OSR entry if we emit an
-        // early deoptimize.
-        succeeded = false;
-      }
-    } else {
-      succeeded = false;
-    }
-  }
-
-  // Revert to the original interrupt calls in the original unoptimized code.
-  if (FLAG_trace_osr) {
-    PrintF("[restoring original interrupt calls in ");
-    function->PrintName();
-    PrintF("]\n");
-  }
-  Deoptimizer::RevertInterruptCode(isolate, *unoptimized);
-
   // If the optimization attempt succeeded, return the AST id tagged as a
   // smi. This tells the builtin that we need to translate the unoptimized
   // frame to an optimized one.
-  if (succeeded) {
+  BailoutId ast_id =
+      (FLAG_concurrent_recompilation && FLAG_concurrent_osr)
+          ? Compiler::CompileForConcurrentOSR(function)
+          : Compiler::CompileForOnStackReplacement(function);
+  if (!ast_id.IsNone()) {
     ASSERT(function->code()->kind() == Code::OPTIMIZED_FUNCTION);
     return Smi::FromInt(ast_id.ToInt());
   } else {
-    if (function->IsMarkedForLazyRecompilation()) {
+    if (function->IsMarkedForLazyRecompilation() ||
+        function->IsMarkedForConcurrentRecompilation()) {
       function->ReplaceCode(function->shared()->code());
     }
     return Smi::FromInt(-1);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetAllocationTimeout) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
@@ skipping 6010 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