Investigate & fix issues around usage_count and deoptimization_count

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 52 matching lines @@
 DEFINE_FLAG(bool, trace_optimizing_compiler, false,
     "Trace only optimizing compiler operations.");
 DEFINE_FLAG(bool, trace_bailout, false, "Print bailout from ssa compiler.");
 DEFINE_FLAG(bool, use_inlining, true, "Enable call-site inlining");
 DEFINE_FLAG(bool, verify_compiler, false,
     "Enable compiler verification assertions");
 DEFINE_FLAG(int, max_speculative_inlining_attempts, 1,
     "Max number of attempts with speculative inlining (precompilation only)");
 
 DECLARE_FLAG(bool, background_compilation);
+DECLARE_FLAG(bool, huge_method_cutoff_in_code_size);
 DECLARE_FLAG(bool, load_deferred_eagerly);
 DECLARE_FLAG(bool, trace_failed_optimization_attempts);
 DECLARE_FLAG(bool, trace_inlining_intervals);
 DECLARE_FLAG(bool, trace_irregexp);
 
 
 bool Compiler::always_optimize_ = false;
 bool Compiler::allow_recompilation_ = true;
 
 #ifndef DART_PRECOMPILED
@@ skipping 376 matching lines @@
   const Array& deopt_info_array =
       Array::Handle(zone, graph_compiler->CreateDeoptInfo(assembler));
   INC_STAT(thread(), total_code_size,
            deopt_info_array.Length() * sizeof(uword));
   // Allocates instruction object. Since this occurs only at safepoint,
   // there can be no concurrent access to the instruction page.
   const Code& code = Code::Handle(
       Code::FinalizeCode(function, assembler, optimized()));
   code.set_is_optimized(optimized());
   code.set_owner(function);
+  if (!function.IsOptimizable()) {
+    // A function with huge unoptimized code can become non-optimizable
+    // after generating unoptimized code.
+    function.set_usage_counter(INT_MIN);
+  }
 
   const Array& intervals = graph_compiler->inlined_code_intervals();
   INC_STAT(thread(), total_code_size,
            intervals.Length() * sizeof(uword));
   code.SetInlinedIntervals(intervals);
 
   const Array& inlined_id_array =
       Array::Handle(zone, graph_compiler->InliningIdToFunction());
   INC_STAT(thread(), total_code_size,
            inlined_id_array.Length() * sizeof(uword));
@@ skipping 1552 matching lines @@
 }
 
 
 void BackgroundCompiler::EnsureInit(Thread* thread) {
   UNREACHABLE();
 }
 
 #endif  // DART_PRECOMPILED
 
 }  // namespace dart