Fix pc descriptor emission for skipped unary oepration +. Eliminates last co19 crash.

runtime/vm/code_generator_ia32.cc

 // Copyright (c) 2011, 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/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/code_generator.h"
 
 #include "lib/error.h"
@@ skipping 1159 matching lines @@
 }
 
 
 void CodeGenerator::VisitUnaryOpNode(UnaryOpNode* node) {
   if (node->kind() == Token::kNOT) {
     // "!" cannot be overloaded, therefore inline it.
     GenerateLogicalNotOp(node);
     return;
   }
   node->operand()->Visit(this);
-  MarkDeoptPoint(node->id(), node->token_index());
   if (node->kind() == Token::kADD) {
     // Unary operator '+' does not exist, it's a NOP, skip it.
     if (!IsResultNeeded(node)) {
       __ popl(EAX);
     }
     return;
   }
+  MarkDeoptPoint(node->id(), node->token_index());
   String& operator_name = String::ZoneHandle();
   if (node->kind() == Token::kSUB) {
     operator_name = String::NewSymbol(Token::Str(Token::kNEGATE));
   } else {
     operator_name = String::NewSymbol(node->Name());
   }
   const int kNumberOfArguments = 1;
   const Array& kNoArgumentNames = Array::Handle();
   GenerateInstanceCall(node->id(),
                        node->token_index(),
@@ skipping 1447 matching lines @@
   const Class& cls = Class::Handle(parsed_function_.function().owner());
   const Script& script = Script::Handle(cls.script());
   Parser::ReportMsg(script, token_index, "Error", error_msg, format, args);
   Isolate::Current()->long_jump_base()->Jump(1, error_msg);
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32