When printing constants in the flow graph truncate them at the first new line character.

runtime/vm/il_printer.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/il_printer.h"
 
 #include "vm/intermediate_language.h"
 #include "vm/os.h"
 #include "vm/parser.h"
 
@@ skipping 185 matching lines @@
   }
 }
 
 
 void Value::PrintTo(BufferFormatter* f) const {
   PrintUse(f, *definition());
 }
 
 
 void ConstantInstr::PrintOperandsTo(BufferFormatter* f) const {
-  f->Print("#%s", value().ToCString());
+  const char* cstr = value().ToCString();
+  const char* new_line = strchr(cstr, '\n');
+  if (new_line == NULL) {
+    f->Print("#%s", cstr);
+  } else {
+    const intptr_t pos = new_line - cstr;
+    char* buffer = Isolate::Current()->current_zone()->Alloc<char>(pos + 1);
+    strncpy(buffer, cstr, pos);
+    buffer[pos] = '\0';
+    f->Print("#%s\\n...", buffer);
+  }
 }
 
 
 void ConstraintInstr::PrintOperandsTo(BufferFormatter* f) const {
   value()->PrintTo(f);
   f->Print(" ^ ");
   constraint()->PrintTo(f);
 }
 
 
@@ skipping 448 matching lines @@
       f->Print(" [");
       locations_[i].PrintTo(f);
       f->Print("]");
     }
   }
   f->Print(" }");
   if (outer_ != NULL) outer_->PrintTo(f);
 }
 
 }  // namespace dart