More general CHA-based inlining and devirtualization for precompiled code.

runtime/vm/flow_graph_inliner.cc

 // Copyright (c) 2013, 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/flow_graph_inliner.h"
 
 #include "vm/block_scheduler.h"
 #include "vm/compiler.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
@@ skipping 608 matching lines @@
                              function.deoptimization_counter()));
 
     // Abort if the inlinable bit on the function is low.
     if (!function.CanBeInlined()) {
       TRACE_INLINING(THR_Print("     Bailout: not inlinable\n"));
       PRINT_INLINING_TREE("Not inlinable",
           &call_data->caller, &function, call_data->call);
       return false;
     }
 
+    // Function has not beed compiled yet.  With lazy compilation a function
+    // that has not been executed won't have any type feedback. In
+    // precompilation mode we don't rely on type feedback.

[srdjan, 2015/10/21 17:37:46]

This can be a problem for Siva's change where we store type feedback in
snapshots and first compilation is optimized. How about checking the invocation
counter instead of HasCode?

[rmacnak, 2015/10/21 18:00:30]

Can this check if the function has an ic data array instead? --collect-code can
drop code but leave the ic data array.

[Florian Schneider, 2015/10/22 13:59:25]

I would opt for checking the ic data array, but I did want to 
change inlining heuristics for regular compilation in this change.

Note that this is exactly the same test that we already have with lazy
compilation. I just moved it from Function::CanBeInlined to here so that I can
skip this condition with precompilation.

[srdjan, 2015/10/22 15:31:26]

OK, to replicate current behavior. CC-ing Siva to know what to fix to enable
inlining in snapshots with instant optimization

+    if (!Compiler::always_optimize() && !function.HasCode()) {
+      TRACE_INLINING(THR_Print("     Bailout: not compiled yet\n"));
+      PRINT_INLINING_TREE("Not compiled",
+          &call_data->caller, &function, call_data->call);
+      return false;
+    }
+
     // Abort if this function has deoptimized too much.
     if (function.deoptimization_counter() >=
         FLAG_deoptimization_counter_threshold) {
       function.set_is_inlinable(false);
       TRACE_INLINING(THR_Print("     Bailout: deoptimization threshold\n"));
       PRINT_INLINING_TREE("Deoptimization threshold exceeded",
           &call_data->caller, &function, call_data->call);
       return false;
     }
 
@@ skipping 1244 matching lines @@
 intptr_t FlowGraphInliner::NextInlineId(const Function& function,
                                         intptr_t parent_id) {
   const intptr_t id = inline_id_to_function_->length();
   inline_id_to_function_->Add(&function);
   caller_inline_id_->Add(parent_id);
   return id;
 }
 
 
 }  // namespace dart