Fix disassembly with background compilation: parsing can report 'errors' in background compilation

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 1357 matching lines @@
 void Compiler::ComputeLocalVarDescriptors(const Code& code) {
   ASSERT(!code.is_optimized());
   const Function& function = Function::Handle(code.function());
   ParsedFunction* parsed_function = new ParsedFunction(
       Thread::Current(), Function::ZoneHandle(function.raw()));
   LocalVarDescriptors& var_descs =
       LocalVarDescriptors::Handle(code.var_descriptors());
   ASSERT(var_descs.IsNull());
   // IsIrregexpFunction have eager var descriptors generation.
   ASSERT(!function.IsIrregexpFunction());
-  // Parser should not produce any errors, therefore no LongJumpScope needed.
-  // (exception is background compilation).
-  ASSERT(!Compiler::IsBackgroundCompilation());
-  Parser::ParseFunction(parsed_function);
-  parsed_function->AllocateVariables();
-  var_descs = parsed_function->node_sequence()->scope()->
-      GetVarDescriptors(function);
-  ASSERT(!var_descs.IsNull());
-  code.set_var_descriptors(var_descs);
+  // In background compilation, parser can produce 'errors": bailouts
+  // if state changed while compiling in background.
+  LongJumpScope jump;
+  if (setjmp(*jump.Set()) == 0) {
+    Parser::ParseFunction(parsed_function);
+    parsed_function->AllocateVariables();
+    var_descs = parsed_function->node_sequence()->scope()->
+        GetVarDescriptors(function);
+    ASSERT(!var_descs.IsNull());
+    code.set_var_descriptors(var_descs);
+  } else {
+    // Only possible with background compilation.
+    ASSERT(Compiler::IsBackgroundCompilation());
+  }
 }
 
 
 RawError* Compiler::CompileAllFunctions(const Class& cls) {
   Thread* thread = Thread::Current();
   Zone* zone = thread->zone();
   Error& error = Error::Handle(zone);
   Array& functions = Array::Handle(zone, cls.functions());
   Function& func = Function::Handle(zone);
   // Class dynamic lives in the vm isolate. Its array fields cannot be set to
@@ skipping 508 matching lines @@
 }
 
 
 void BackgroundCompiler::EnsureInit(Thread* thread) {
   UNREACHABLE();
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart