[turbofan] Move graph trimming functionality to dedicated GraphTrimmer.

src/compiler/pipeline.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/pipeline.h"
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
 #include "src/base/adapters.h"
 #include "src/base/platform/elapsed-timer.h"
 #include "src/compiler/ast-graph-builder.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/basic-block-instrumentor.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/common-operator-reducer.h"
 #include "src/compiler/control-flow-optimizer.h"
 #include "src/compiler/control-reducer.h"
 #include "src/compiler/frame-elider.h"
 #include "src/compiler/graph-replay.h"
+#include "src/compiler/graph-trimmer.h"
 #include "src/compiler/graph-visualizer.h"
 #include "src/compiler/greedy-allocator.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/instruction-selector.h"
 #include "src/compiler/js-builtin-reducer.h"
 #include "src/compiler/js-context-specialization.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-inlining.h"
 #include "src/compiler/js-intrinsic-lowering.h"
 #include "src/compiler/js-type-feedback.h"
@@ skipping 614 matching lines @@
 
 
 struct LateControlReductionPhase {
   static const char* phase_name() { return "late control reduction"; }
   void Run(PipelineData* data, Zone* temp_zone) {
     ControlReducer::ReduceGraph(temp_zone, data->jsgraph(), 0);
   }
 };
 
 
+struct EarlyGraphTrimmingPhase {
+  static const char* phase_name() { return "early graph trimming"; }
+  void Run(PipelineData* data, Zone* temp_zone) {
+    GraphTrimmer trimmer(temp_zone, data->graph());
+    NodeVector roots(temp_zone);
+    data->jsgraph()->GetCachedNodes(&roots);
+    trimmer.TrimGraph(roots.begin(), roots.end());
+  }
+};
+
+
+struct LateGraphTrimmingPhase {
+  static const char* phase_name() { return "late graph trimming"; }
+  void Run(PipelineData* data, Zone* temp_zone) {
+    GraphTrimmer trimmer(temp_zone, data->graph());
+    NodeVector roots(temp_zone);
+    data->jsgraph()->GetCachedNodes(&roots);
+    trimmer.TrimGraph(roots.begin(), roots.end());
+  }
+};
+
+
 struct StressLoopPeelingPhase {
   static const char* phase_name() { return "stress loop peeling"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     // Peel the first outer loop for testing.
     // TODO(titzer): peel all loops? the N'th loop? Innermost loops?
     LoopTree* loop_tree = LoopFinder::BuildLoopTree(data->graph(), temp_zone);
     if (loop_tree != NULL && loop_tree->outer_loops().size() > 0) {
       LoopPeeler::Peel(data->graph(), data->common(), loop_tree,
                        loop_tree->outer_loops()[0], temp_zone);
@@ skipping 351 matching lines @@
 
   if (info()->is_context_specializing()) {
     // Specialize the code to the context as aggressively as possible.
     Run<ContextSpecializerPhase>();
     RunPrintAndVerify("Context specialized", true);
   }
 
   Run<InliningPhase>();
   RunPrintAndVerify("Inlined", true);
 
+  Run<EarlyGraphTrimmingPhase>();
+  RunPrintAndVerify("Early trimmed", true);
+
   if (FLAG_print_turbo_replay) {
     // Print a replay of the initial graph.
     GraphReplayPrinter::PrintReplay(data.graph());
   }
 
   // Bailout here in case target architecture is not supported.
   if (!SupportedTarget()) return Handle<Code>::null();
 
   if (info()->is_typing_enabled()) {
     // Type the graph.
@@ skipping 46 matching lines @@
       if (info()->bailout_reason() != kNoReason) return Handle<Code>::null();
       RunPrintAndVerify("OSR deconstruction");
     }
   }
 
   // Lower any remaining generic JSOperators.
   Run<GenericLoweringPhase>();
   // TODO(jarin, rossberg): Remove UNTYPED once machine typing works.
   RunPrintAndVerify("Lowered generic", true);
 
+  Run<LateGraphTrimmingPhase>();
+  // TODO(jarin, rossberg): Remove UNTYPED once machine typing works.
+  RunPrintAndVerify("Late trimmed", true);
+
   BeginPhaseKind("block building");
 
   data.source_positions()->RemoveDecorator();
 
   return ScheduleAndGenerateCode(
       Linkage::ComputeIncoming(data.instruction_zone(), info()));
 }
 
 
 Handle<Code> Pipeline::GenerateCodeForTesting(CompilationInfo* info,
@@ skipping 227 matching lines @@
     tcf << AsC1VRegisterAllocationData("CodeGen",
                                        data->register_allocation_data());
   }
 
   data->DeleteRegisterAllocationZone();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8