Fix issue 3874: non-deterministic AST generation caused by exceptions being thrown during parsing (…

runtime/vm/parser.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/parser.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
@@ skipping 8100 matching lines @@
                                                    kNumArguments,
                                                    Object::empty_array(),
                                                    Resolver::kIsQualified));
       ASSERT(!func.IsNull());
       ASSERT(func.kind() == RawFunction::kConstImplicitGetter);
       Object& const_value = Object::Handle(
           DartEntry::InvokeFunction(func, Object::empty_array()));
       if (const_value.IsError()) {
         const Error& error = Error::Cast(const_value);
         if (error.IsUnhandledException()) {
+          // An exception may not occur in every parse attempt, i.e., the
+          // generated AST is not deterministic. Therefore mark the function as
+          // not optimizable.
+          current_function().set_is_optimizable(false);
           field.set_value(Instance::Handle());
           // It is a compile-time error if evaluation of a compile-time constant
           // would raise an exception.
           AppendErrorMsg(error, TokenPos(),
                          "error initializing const field '%s'",
                          String::Handle(field.name()).ToCString());
         } else {
           Isolate::Current()->long_jump_base()->Jump(1, error);
         }
       }
@@ skipping 43 matching lines @@
     arg_values.SetAt((i + kNumExtraArgs), arg->AsLiteralNode()->literal());
   }
   const Array& arg_descriptor =
       Array::Handle(ArgumentsDescriptor::New(num_arguments,
                                              arguments->names()));
   const Object& result =
       Object::Handle(DartEntry::InvokeFunction(constructor,
                                                arg_values,
                                                arg_descriptor));
   if (result.IsError()) {
+      // An exception may not occur in every parse attempt, i.e., the
+      // generated AST is not deterministic. Therefore mark the function as
+      // not optimizable.
+      current_function().set_is_optimizable(false);
       if (result.IsUnhandledException()) {
         return result.raw();
       } else {
         Isolate::Current()->long_jump_base()->Jump(1, Error::Cast(result));
         UNREACHABLE();
         return Object::null();
       }
   } else {
     if (!instance.IsNull()) {
       instance ^= instance.Canonicalize();
@@ skipping 1794 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart