Fix background compilation: handle compilation abort during parsing.

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 1153 matching lines @@
                num_tokens_after - num_tokens_before);
     }
 
     CompileParsedFunctionHelper helper(parsed_function, optimized, osr_id);
     const bool success = helper.Compile(pipeline);
     if (!success) {
       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());
+          }
           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());
         }
@@ skipping 34 matching lines @@
       THR_Print("*** BEGIN CODE\n");
       Disassembler::DisassembleCode(function, true);
       THR_Print("*** END CODE\n");
     }
     DEBUG_ONLY(CheckInliningIntervals(function));
     return Error::null();
   } else {
     Thread* const thread = Thread::Current();
     StackZone stack_zone(thread);
     Error& error = Error::Handle();
-    // We got an error during compilation.
+    // We got an error during compilation or it is a bailout from background
+    // compilation (e.g., during parsing with EnsureIsFinalized).
     error = thread->sticky_error();
     thread->clear_sticky_error();
+    if (error.raw() == Object::background_compilation_error().raw()) {
+      // Exit compilation, retry it later.
+      if (FLAG_trace_bailout) {
+        THR_Print("Aborted background compilation: %s\n",
+            function.ToFullyQualifiedCString());
+      }
+      return Error::null();
+    }
     // Unoptimized compilation or precompilation may encounter compile-time
     // errors, but regular optimized compilation should not.
     ASSERT(!optimized);
     // Do not attempt to optimize functions that can cause errors.
     function.set_is_optimizable(false);
     return error.raw();
   }
   UNREACHABLE();
   return Error::null();
 }
@@ skipping 642 matching lines @@
 }
 
 
 void BackgroundCompiler::EnsureInit(Thread* thread) {
   UNREACHABLE();
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart