Less aggressive polling when concurrently compiling for OSR.

src/full-codegen.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 1600 matching lines @@
     return true;
   }
 
   return false;
 }
 
 
 void BackEdgeTable::Patch(Isolate* isolate,
                           Code* unoptimized) {
   DisallowHeapAllocation no_gc;
-  Code* replacement_code =
-      isolate->builtins()->builtin(Builtins::kOnStackReplacement);
+  Code* patch = isolate->builtins()->builtin(Builtins::kOnStackReplacement);
 
   // Iterate over the back edge table and patch every interrupt
   // call to an unconditional call to the replacement code.
   int loop_nesting_level = unoptimized->allow_osr_at_loop_nesting_level();
 
   BackEdgeTable back_edges(unoptimized, &no_gc);
   for (uint32_t i = 0; i < back_edges.length(); i++) {
     if (static_cast<int>(back_edges.loop_depth(i)) == loop_nesting_level) {
       ASSERT_EQ(INTERRUPT, GetBackEdgeState(isolate,
                                             unoptimized,
                                             back_edges.pc(i)));
-      PatchAt(unoptimized, back_edges.pc(i), replacement_code);
+      PatchAt(unoptimized, back_edges.pc(i), ON_STACK_REPLACEMENT, patch);
     }
   }
 
   unoptimized->set_back_edges_patched_for_osr(true);
   ASSERT(Verify(isolate, unoptimized, loop_nesting_level));
 }
 
 
 void BackEdgeTable::Revert(Isolate* isolate,
                            Code* unoptimized) {
   DisallowHeapAllocation no_gc;
-  Code* interrupt_code =
-      isolate->builtins()->builtin(Builtins::kInterruptCheck);
+  Code* patch = isolate->builtins()->builtin(Builtins::kInterruptCheck);
 
   // Iterate over the back edge table and revert the patched interrupt calls.
   ASSERT(unoptimized->back_edges_patched_for_osr());
   int loop_nesting_level = unoptimized->allow_osr_at_loop_nesting_level();
 
   BackEdgeTable back_edges(unoptimized, &no_gc);
   for (uint32_t i = 0; i < back_edges.length(); i++) {
     if (static_cast<int>(back_edges.loop_depth(i)) <= loop_nesting_level) {
-      ASSERT_EQ(ON_STACK_REPLACEMENT, GetBackEdgeState(isolate,
-                                                       unoptimized,
-                                                       back_edges.pc(i)));
-      RevertAt(unoptimized, back_edges.pc(i), interrupt_code);
+      ASSERT_NE(INTERRUPT, GetBackEdgeState(isolate,
+                                            unoptimized,
+                                            back_edges.pc(i)));
+      PatchAt(unoptimized, back_edges.pc(i), INTERRUPT, patch);
     }
   }
 
   unoptimized->set_back_edges_patched_for_osr(false);
   unoptimized->set_allow_osr_at_loop_nesting_level(0);
   // Assert that none of the back edges are patched anymore.
   ASSERT(Verify(isolate, unoptimized, -1));
 }
 
 
+void BackEdgeTable::AddStackCheck(CompilationInfo* info) {
+  DisallowHeapAllocation no_gc;
+  Isolate* isolate = info->isolate();
+  Code* code = info->shared_info()->code();
+  Address pc = code->instruction_start() + info->osr_pc_offset();
+  ASSERT_EQ(ON_STACK_REPLACEMENT, GetBackEdgeState(isolate, code, pc));
+  Code* patch = isolate->builtins()->builtin(Builtins::kOsrAfterStackCheck);
+  PatchAt(code, pc, OSR_AFTER_STACK_CHECK, patch);
+}
+
+
+void BackEdgeTable::RemoveStackCheck(CompilationInfo* info) {
+  DisallowHeapAllocation no_gc;
+  Isolate* isolate = info->isolate();
+  Code* code = info->shared_info()->code();
+  Address pc = code->instruction_start() + info->osr_pc_offset();
+  if (GetBackEdgeState(isolate, code, pc) == OSR_AFTER_STACK_CHECK) {
+    Code* patch = isolate->builtins()->builtin(Builtins::kOnStackReplacement);
+    PatchAt(code, pc, ON_STACK_REPLACEMENT, patch);
+  }
+}
+
+
 #ifdef DEBUG
 bool BackEdgeTable::Verify(Isolate* isolate,
                            Code* unoptimized,
                            int loop_nesting_level) {
   DisallowHeapAllocation no_gc;
   BackEdgeTable back_edges(unoptimized, &no_gc);
   for (uint32_t i = 0; i < back_edges.length(); i++) {
     uint32_t loop_depth = back_edges.loop_depth(i);
     CHECK_LE(static_cast<int>(loop_depth), Code::kMaxLoopNestingMarker);
     // Assert that all back edges for shallower loops (and only those)
     // have already been patched.
     CHECK_EQ((static_cast<int>(loop_depth) <= loop_nesting_level),
              GetBackEdgeState(isolate,
                               unoptimized,
                               back_edges.pc(i)) != INTERRUPT);
   }
   return true;
 }
 #endif  // DEBUG
 
 
 #undef __
 
 
 } }  // namespace v8::internal