Fix OSR for nested loops.

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 7591 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"))) {
-      isolate->runtime_profiler()->AttemptOnStackReplacement(*function);
-      unoptimized->set_allow_osr_at_loop_nesting_level(
-          Code::kMaxLoopNestingMarker);
+      for (int i = 0; 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("parallel"))) {
       function->MarkForParallelRecompilation();
     }
   }
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_WaitUntilOptimized) {
@@ skipping 76 matching lines @@
     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 stack check table to find
     // the AST id matching the PC.
     Address start = unoptimized->instruction_start();
     unsigned target_pc_offset = static_cast<unsigned>(frame->pc() - start);
-    Address table_cursor = start + unoptimized->stack_check_table_offset();
+    Address table_cursor = start + unoptimized->back_edge_table_offset();
     uint32_t table_length = Memory::uint32_at(table_cursor);
     table_cursor += kIntSize;
+    static const int kBackEdgeEntrySize = 2 * kIntSize + kOneByteSize;
+    uint8_t loop_depth = 0;
     for (unsigned i = 0; i < table_length; ++i) {
       // Table entries are (AST id, pc offset) pairs.
       uint32_t pc_offset = Memory::uint32_at(table_cursor + kIntSize);
       if (pc_offset == target_pc_offset) {
         ast_id = BailoutId(static_cast<int>(Memory::uint32_at(table_cursor)));
+        loop_depth = Memory::uint8_at(table_cursor + 2 * kIntSize);
         break;
       }
-      table_cursor += 2 * kIntSize;
+      table_cursor += kBackEdgeEntrySize;
     }
     ASSERT(!ast_id.IsNone());
     if (FLAG_trace_osr) {
-      PrintF("[replacing on-stack at AST id %d in ", ast_id.ToInt());
+      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(
@@ skipping 14 matching lines @@
     }
   }
 
   // Revert to the original stack checks in the original unoptimized code.
   if (FLAG_trace_osr) {
     PrintF("[restoring original stack checks in ");
     function->PrintName();
     PrintF("]\n");
   }
   InterruptStub interrupt_stub;
-  Handle<Code> check_code = interrupt_stub.GetCode(isolate);
+  Handle<Code> interrupt_code = interrupt_stub.GetCode(isolate);
   Handle<Code> replacement_code = isolate->builtins()->OnStackReplacement();
-  Deoptimizer::RevertStackCheckCode(*unoptimized,
-                                    *check_code,
-                                    *replacement_code);
+  Deoptimizer::RevertInterruptCode(*unoptimized,
+                                   *interrupt_code,
+                                   *replacement_code);
 
   // Allow OSR only at nesting level zero again.
   unoptimized->set_allow_osr_at_loop_nesting_level(0);
 
   // 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) {
     ASSERT(function->code()->kind() == Code::OPTIMIZED_FUNCTION);
     return Smi::FromInt(ast_id.ToInt());
@@ skipping 5276 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