Retry background compilation if an assumption is invalidated

runtime/vm/compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 1149 matching lines @@
       } else {
         // If the error isn't due to an out of range branch offset, we don't
         // try again (done = true), and indicate that we did not finish
         // compiling (is_compiled = false).
         if (FLAG_trace_bailout) {
           THR_Print("%s\n", error.ToErrorCString());
         }
         done = true;
       }
 
-      // Clear the error if it was not a real error, but just a bailout.
-      if (error.IsLanguageError() &&
+      // If is is not a background compilation, clear the error if it was not a
+      // real error, but just a bailout. If we're it a background compilation
+      // this will be dealt with in the caller.
+      if (!Compiler::IsBackgroundCompilation() && error.IsLanguageError() &&
           (LanguageError::Cast(error).kind() == Report::kBailout)) {
         thread()->clear_sticky_error();
       }
       is_compiled = false;
     }
     // Reset global isolate state.
     thread()->set_deopt_id(prev_deopt_id);
   }
   return is_compiled;
 }
@@ skipping 88 matching lines @@
       }
     } else {
       if (optimized) {
         if (Compiler::IsBackgroundCompilation()) {
           // Try again later, background compilation may abort because of
           // state change during compilation.
           if (FLAG_trace_compiler) {
             THR_Print("Aborted background compilation: %s\n",
                 function.ToFullyQualifiedCString());
           }
+          {
+            // If it was a bailout, then disable optimization.
+            Error& error = Error::Handle();
+            // We got an error during compilation.
+            error = thread->sticky_error();
+            thread->clear_sticky_error();
+            if (error.IsLanguageError() &&
+                LanguageError::Cast(error).kind() == Report::kBailout) {
+              if (FLAG_trace_compiler) {
+                THR_Print("--> disabling optimizations for '%s'\n",
+                          function.ToFullyQualifiedCString());
+              }
+              function.SetIsOptimizable(false);
+            }
+          }
           return Error::null();
         }
         // Optimizer bailed out. Disable optimizations and never try again.
         if (trace_compiler) {
           THR_Print("--> disabling optimizations for '%s'\n",
                     function.ToFullyQualifiedCString());
         } else if (FLAG_trace_failed_optimization_attempts) {
           THR_Print("Cannot optimize: %s\n",
                     function.ToFullyQualifiedCString());
         }
         function.SetIsOptimizable(false);
         return Error::null();
       } else {
         // Encountered error.
         Error& error = Error::Handle();
         // We got an error during compilation.
         error = thread->sticky_error();
         thread->clear_sticky_error();
+        // The non-optimizing compiler should not bail out.
         ASSERT(error.IsLanguageError() &&
                LanguageError::Cast(error).kind() != Report::kBailout);
         return error.raw();
       }
     }
 
     per_compile_timer.Stop();
 
     if (trace_compiler && success) {
       THR_Print("--> '%s' entry: %#" Px " size: %" Pd " time: %" Pd64 " us\n",
@@ skipping 555 matching lines @@
         thread->compiler_stats()->Clear();
 #endif  // PRODUCT
 
         QueueElement* qelem = NULL;
         { MonitorLocker ml(queue_monitor_);
           if (function_queue()->IsEmpty()) {
             // We are shutting down, queue was cleared.
             function = Function::null();
           } else {
             qelem = function_queue()->Remove();
-            if (FLAG_stress_test_background_compilation) {
-              const Function& old = Function::Handle(qelem->Function());
+            const Function& old = Function::Handle(qelem->Function());
+            if ((!old.HasOptimizedCode() && old.IsOptimizable()) ||
+                 FLAG_stress_test_background_compilation) {
               if (Compiler::CanOptimizeFunction(thread, old)) {
                 QueueElement* repeat_qelem = new QueueElement(old);
                 function_queue()->Add(repeat_qelem);
               }
             }
             function = function_queue()->PeekFunction();
           }
         }
         if (qelem != NULL) {
           delete qelem;
@@ skipping 278 matching lines @@
 
 
 bool BackgroundCompiler::IsDisabled() {
   UNREACHABLE();
   return true;
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart