Revert several inlining related changes.

runtime/vm/flow_graph_inliner.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/flow_graph_inliner.h"
 
 #include "vm/compiler.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_optimizer.h"
 #include "vm/il_printer.h"
 #include "vm/intrinsifier.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, trace_inlining, false, "Trace inlining");
 DEFINE_FLAG(charp, inlining_filter, NULL, "Inline only in named function");
-DEFINE_FLAG(int, inlining_size_threshold, 250,
-            "Inline only functions with up to threshold instructions");
-DEFINE_FLAG(int, inlining_growth_factor, 3,
-            "Stop inlining when a function grows by the factor");
 DECLARE_FLAG(bool, print_flow_graph);
 DECLARE_FLAG(int, deoptimization_counter_threshold);
 
 #define TRACE_INLINING(statement)                                              \
   do {                                                                         \
     if (FLAG_trace_inlining) statement;                                        \
   } while (false)
 
 
 // Test if a call is recursive by looking in the deoptimization environment.
 static bool IsCallRecursive(const Function& function, Definition* call) {
   Environment* env = call->env();
   while (env != NULL) {
     if (function.raw() == env->function().raw()) return true;
     env = env->outer();
   }
   return false;
 }
 
 
 class CallSiteInliner : public FlowGraphVisitor {
  public:
   explicit CallSiteInliner(FlowGraph* flow_graph)
       : FlowGraphVisitor(flow_graph->postorder()),
         caller_graph_(flow_graph),
         next_ssa_temp_index_(flow_graph->max_virtual_register_number()),
-        inlined_(false),
-        initial_size_(flow_graph->InstructionCount()),
-        inlined_size_(0),
-        static_calls_(),
-        closure_calls_(),
-        instance_calls_() { }
+        inlined_(false) { }
 
-  void VisitClosureCall(ClosureCallInstr* call) {
-    closure_calls_.Add(call);
-  }
-
-  void VisitPolymorphicInstanceCall(PolymorphicInstanceCallInstr* call) {
-    instance_calls_.Add(call);
-  }
-
-  void VisitStaticCall(StaticCallInstr* call) {
-    if (call->function().is_inlinable()) static_calls_.Add(call);
-  }
-
-  void FindCallSites() {
-    VisitBlocks();
-  }
-
-  void InlineCalls() {
-    InlineStaticCalls();
-    InlineClosureCalls();
-    InlineInstanceCalls();
-  }
-
-  bool inlined() const { return inlined_; }
-
-  double GrowthFactor() const {
-    return static_cast<double>(inlined_size_) /
-        static_cast<double>(initial_size_);
-  }
-
- private:
   bool TryInlining(const Function& function,
                    GrowableArray<Value*>* arguments,
                    Definition* call) {
     TRACE_INLINING(OS::Print("  => %s\n", function.ToCString()));
 
     // Abort if the inlinable bit on the function is low.
     if (!function.is_inlinable()) {
       TRACE_INLINING(OS::Print("     Bailout: not inlinable\n"));
       return false;
     }
@@ skipping 42 matching lines @@
       if ((function.deoptimization_counter() <
            FLAG_deoptimization_counter_threshold) &&
           function.HasCode()) {
         const Code& unoptimized_code =
             Code::Handle(function.unoptimized_code());
         isolate->set_ic_data_array(unoptimized_code.ExtractTypeFeedbackArray());
       }
 
       // Build the callee graph.
       FlowGraphBuilder builder(parsed_function);
-      builder.SetInitialBlockId(caller_graph_->max_block_id());
       FlowGraph* callee_graph =
           builder.BuildGraph(FlowGraphBuilder::kValueContext);
 
+      // Abort if the callee graph contains control flow.
+      if (callee_graph->preorder().length() != 2) {
+        function.set_is_inlinable(false);
+        isolate->set_long_jump_base(base);
+        isolate->set_ic_data_array(prev_ic_data.raw());
+        TRACE_INLINING(OS::Print("     Bailout: control flow\n"));
+        return false;
+      }
+
       // Compute SSA on the callee graph, catching bailouts.
       callee_graph->ComputeSSA(next_ssa_temp_index_);
       callee_graph->ComputeUseLists();
 
       // TODO(zerny): Do more optimization passes on the callee graph.
       FlowGraphOptimizer optimizer(callee_graph);
       optimizer.ApplyICData();
       callee_graph->ComputeUseLists();
 
       if (FLAG_trace_inlining && FLAG_print_flow_graph) {
         OS::Print("Callee graph for inlining %s\n",
                   parsed_function.function().ToFullyQualifiedCString());
         FlowGraphPrinter printer(*callee_graph);
         printer.PrintBlocks();
       }
 
-      // If result is more than size threshold then abort.
-      // TODO(zerny): Do this after CP and dead code elimination.
-      intptr_t size = callee_graph->InstructionCount();
-      if (size > FLAG_inlining_size_threshold) {
-        function.set_is_inlinable(false);
-        isolate->set_long_jump_base(base);
-        isolate->set_deopt_id(prev_deopt_id);
-        isolate->set_ic_data_array(prev_ic_data.raw());
-        TRACE_INLINING(OS::Print("     Bailout: graph size %"Pd"\n", size));
-        return false;
-      }
-
-      // If the growth factor is more than threshold abort.
-      double growth =
-          static_cast<double>(inlined_size_ + size) /
-          static_cast<double>(initial_size_);
-      if (growth > static_cast<double>(FLAG_inlining_growth_factor)) {
-        function.set_is_inlinable(false);
-        isolate->set_long_jump_base(base);
-        isolate->set_deopt_id(prev_deopt_id);
-        isolate->set_ic_data_array(prev_ic_data.raw());
-        TRACE_INLINING(OS::Print("     Bailout: growth factor %f\n",
-                                 growth));
-        return false;
-      }
+      // TODO(zerny): If result is more than size threshold then abort.
 
       // TODO(zerny): If effort is less than threshold then inline recursively.
 
       // Plug result in the caller graph.
       caller_graph_->InlineCall(call, callee_graph);
       next_ssa_temp_index_ = caller_graph_->max_virtual_register_number();
 
+      // Check that inlining maintains use lists.
+      DEBUG_ASSERT(caller_graph_->ValidateUseLists());
+
       // Remove push arguments of the call.
       for (intptr_t i = 0; i < call->ArgumentCount(); ++i) {
         PushArgumentInstr* push = call->ArgumentAt(i);
         push->ReplaceUsesWith(push->value()->definition());
         push->RemoveFromGraph();
       }
 
       // Replace formal parameters with actuals.
       intptr_t arg_index = 0;
       GrowableArray<Definition*>* defns =
           callee_graph->graph_entry()->initial_definitions();
       for (intptr_t i = 0; i < defns->length(); ++i) {
         ParameterInstr* param = (*defns)[i]->AsParameter();
         if (param != NULL) {
           param->ReplaceUsesWith((*arguments)[arg_index++]->definition());
         }
       }
       ASSERT(arg_index == arguments->length());
 
       // Replace callee's null constant with caller's null constant.
       callee_graph->graph_entry()->constant_null()->ReplaceUsesWith(
           caller_graph_->graph_entry()->constant_null());
 
       TRACE_INLINING(OS::Print("     Success\n"));
 
-      // Check that inlining maintains use lists.
-      DEBUG_ASSERT(caller_graph_->ValidateUseLists());
-
       // Build succeeded so we restore the bailout jump.
       inlined_ = true;
-      inlined_size_ += size;
       isolate->set_long_jump_base(base);
       isolate->set_deopt_id(prev_deopt_id);
       isolate->set_ic_data_array(prev_ic_data.raw());
       return true;
     } else {
       Error& error = Error::Handle();
       error = isolate->object_store()->sticky_error();
       isolate->object_store()->clear_sticky_error();
       isolate->set_long_jump_base(base);
       isolate->set_deopt_id(prev_deopt_id);
       isolate->set_ic_data_array(prev_ic_data.raw());
       TRACE_INLINING(OS::Print("     Bailout: %s\n", error.ToErrorCString()));
       return false;
     }
   }
 
-  void InlineStaticCalls() {
-    TRACE_INLINING(OS::Print("  Static Calls (%d)\n",
-                             static_calls_.length()));
-    for (intptr_t i = 0; i < static_calls_.length(); ++i) {
-      StaticCallInstr* call = static_calls_[i];
-      GrowableArray<Value*> arguments(call->ArgumentCount());
-      for (int i = 0; i < call->ArgumentCount(); ++i) {
-        arguments.Add(call->ArgumentAt(i)->value());
-      }
-      TryInlining(call->function(), &arguments, call);
+  void VisitClosureCall(ClosureCallInstr* call) {
+    TRACE_INLINING(OS::Print("  ClosureCall\n"));
+    // Find the closure of the callee.
+    ASSERT(call->ArgumentCount() > 0);
+    const CreateClosureInstr* closure =
+        call->ArgumentAt(0)->value()->definition()->AsCreateClosure();
+    if (closure == NULL) {
+      TRACE_INLINING(OS::Print("     Bailout: non-closure operator\n"));
+      return;
     }
+    GrowableArray<Value*> arguments(call->ArgumentCount() - 1);
+    for (int i = 1; i < call->ArgumentCount(); ++i) {
+      arguments.Add(call->ArgumentAt(i)->value());
+    }
+    TryInlining(closure->function(), &arguments, call);
   }
 
-  void InlineClosureCalls() {
-    TRACE_INLINING(OS::Print("  Closure Calls (%d)\n",
-                             closure_calls_.length()));
-    for (intptr_t i = 0; i < closure_calls_.length(); ++i) {
-      ClosureCallInstr* call = closure_calls_[i];
-      // Find the closure of the callee.
-      ASSERT(call->ArgumentCount() > 0);
-      const CreateClosureInstr* closure =
-          call->ArgumentAt(0)->value()->definition()->AsCreateClosure();
-      if (closure == NULL) {
-        TRACE_INLINING(OS::Print("     Bailout: non-closure operator\n"));
-        continue;
-      }
-      GrowableArray<Value*> arguments(call->ArgumentCount() - 1);
-      for (int i = 1; i < call->ArgumentCount(); ++i) {
-        arguments.Add(call->ArgumentAt(i)->value());
-      }
-      TryInlining(closure->function(), &arguments, call);
+  void VisitPolymorphicInstanceCall(PolymorphicInstanceCallInstr* instr) {
+    TRACE_INLINING(OS::Print("  PolymorphicInstanceCall\n"));
+    const ICData& ic_data = instr->ic_data();
+    const Function& target = Function::ZoneHandle(ic_data.GetTargetAt(0));
+    if (instr->with_checks()) {
+      TRACE_INLINING(OS::Print("    Bailout: %"Pd" checks target '%s'\n",
+          ic_data.NumberOfChecks(),
+          target.ToCString()));
+      return;
     }
+
+    GrowableArray<Value*> arguments(instr->ArgumentCount());
+    for (int i = 0; i < instr->ArgumentCount(); ++i) {
+      arguments.Add(instr->ArgumentAt(i)->value());
+    }
+
+    TryInlining(target, &arguments, instr);
   }
 
-  void InlineInstanceCalls() {
-    TRACE_INLINING(OS::Print("  Polymorphic Instance Calls (%d)\n",
-                             instance_calls_.length()));
-    for (intptr_t i = 0; i < instance_calls_.length(); ++i) {
-      PolymorphicInstanceCallInstr* instr = instance_calls_[i];
-      const ICData& ic_data = instr->ic_data();
-      const Function& target = Function::ZoneHandle(ic_data.GetTargetAt(0));
-      if (instr->with_checks()) {
-        TRACE_INLINING(OS::Print("     Bailout: %"Pd" checks target '%s'\n",
-                                 ic_data.NumberOfChecks(),
-                                 target.ToCString()));
-        continue;
-      }
-      GrowableArray<Value*> arguments(instr->ArgumentCount());
-      for (int i = 0; i < instr->ArgumentCount(); ++i) {
-        arguments.Add(instr->ArgumentAt(i)->value());
-      }
-      TryInlining(target, &arguments, instr);
+  void VisitStaticCall(StaticCallInstr* call) {
+    TRACE_INLINING(OS::Print("  StaticCall\n"));
+    GrowableArray<Value*> arguments(call->ArgumentCount());
+    for (int i = 0; i < call->ArgumentCount(); ++i) {
+      arguments.Add(call->ArgumentAt(i)->value());
     }
+    TryInlining(call->function(), &arguments, call);
   }
 
+  bool inlined() const { return inlined_; }
+
+ private:
   FlowGraph* caller_graph_;
   intptr_t next_ssa_temp_index_;
   bool inlined_;
-  intptr_t initial_size_;
-  intptr_t inlined_size_;
-
-  GrowableArray<StaticCallInstr*> static_calls_;
-  GrowableArray<ClosureCallInstr*> closure_calls_;
-  GrowableArray<PolymorphicInstanceCallInstr*> instance_calls_;
 };
 
 
 void FlowGraphInliner::Inline() {
   if ((FLAG_inlining_filter != NULL) &&
       (strstr(flow_graph_->
               parsed_function().function().ToFullyQualifiedCString(),
               FLAG_inlining_filter) == NULL)) {
     return;
   }
 
   TRACE_INLINING(OS::Print(
       "Inlining calls in %s\n",
       flow_graph_->parsed_function().function().ToCString()));
 
   if (FLAG_trace_inlining && FLAG_print_flow_graph) {
     OS::Print("Before Inlining of %s\n", flow_graph_->
               parsed_function().function().ToFullyQualifiedCString());
     FlowGraphPrinter printer(*flow_graph_);
     printer.PrintBlocks();
   }
 
   CallSiteInliner inliner(flow_graph_);
-  inliner.FindCallSites();
-  inliner.InlineCalls();
+  inliner.VisitBlocks();
 
   if (inliner.inlined()) {
-    if (FLAG_trace_inlining) {
-      OS::Print("Inlining growth factor: %f\n", inliner.GrowthFactor());
-      if (FLAG_print_flow_graph) {
-        OS::Print("After Inlining of %s\n", flow_graph_->
-                  parsed_function().function().ToFullyQualifiedCString());
-        FlowGraphPrinter printer(*flow_graph_);
-        printer.PrintBlocks();
-      }
+    if (FLAG_trace_inlining && FLAG_print_flow_graph) {
+      OS::Print("After Inlining of %s\n", flow_graph_->
+                parsed_function().function().ToFullyQualifiedCString());
+      FlowGraphPrinter printer(*flow_graph_);
+      printer.PrintBlocks();
     }
   }
 }
 
 }  // namespace dart