Improve inlining decision: --inline_getters_setters_smaller_than (default 10). Don not inline gette…

runtime/vm/flow_graph_inliner.cc

Index: runtime/vm/flow_graph_inliner.cc
===================================================================
--- runtime/vm/flow_graph_inliner.cc	(revision 32381)
+++ runtime/vm/flow_graph_inliner.cc	(working copy)
@@ -26,6 +26,8 @@
 DEFINE_FLAG(charp, inlining_filter, NULL, "Inline only in named function");
 
 // Flags for inlining heuristics.
+DEFINE_FLAG(int, inline_getters_setters_smaller_than, 10,
+    "Always inline getters and setters that have fewer instructions");
 DEFINE_FLAG(int, inlining_depth_threshold, 3,
     "Inline function calls up to threshold nesting depth");
 DEFINE_FLAG(int, inlining_size_threshold, 25,
@@ -363,7 +365,8 @@
       // Prevent methods becoming humongous and thus slow to compile.
       return false;
     }
-    if (instr_count <= FLAG_inlining_size_threshold) {
+    // 'instr_count' can be 0 if it was not computed yet.
+    if ((instr_count != 0) && (instr_count <= FLAG_inlining_size_threshold)) {
       return true;
     }
     if (call_site_count <= FLAG_inlining_callee_call_sites_threshold) {
@@ -373,7 +376,7 @@
         (instr_count <= FLAG_inlining_constant_arguments_size_threshold)) {
       return true;
     }
-    if (MethodRecognizer::AlwaysInline(callee)) {
+    if (FlowGraphInliner::AlwaysInline(callee)) {
       return true;
     }
     return false;
@@ -775,7 +778,7 @@
         }
       }
       const Function& target = call->function();
-      if (!MethodRecognizer::AlwaysInline(target) &&
+      if (!FlowGraphInliner::AlwaysInline(target) &&
           (call_info[call_idx].ratio * 100) < FLAG_inlining_hotness) {
         TRACE_INLINING(OS::Print(
             "  => %s (deopt count %d)\n     Bailout: cold %f\n",
@@ -847,7 +850,7 @@
 
       const ICData& ic_data = call->ic_data();
       const Function& target = Function::ZoneHandle(ic_data.GetTargetAt(0));
-      if (!MethodRecognizer::AlwaysInline(target) &&
+      if (!FlowGraphInliner::AlwaysInline(target) &&
           (call_info[call_idx].ratio * 100) < FLAG_inlining_hotness) {
         TRACE_INLINING(OS::Print(
             "  => %s (deopt count %d)\n     Bailout: cold %f\n",
@@ -1446,6 +1449,18 @@
 }
 
 
+bool FlowGraphInliner::AlwaysInline(const Function& function) {
+  if (function.IsImplicitGetterFunction() || function.IsGetterFunction() ||
+      function.IsImplicitSetterFunction() || function.IsSetterFunction()) {
+    const intptr_t count = function.optimized_instruction_count();
+    if ((count != 0) && (count < FLAG_inline_getters_setters_smaller_than)) {
+      return true;
+    }
+  }
+  return MethodRecognizer::AlwaysInline(function);
+}
+
+
 void FlowGraphInliner::Inline() {
   // Collect graph info and store it on the function.
   // We might later use it for an early bailout from the inlining.