[turbofan] Effect linearization after representation inference.

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/branch-elimination.h"
 #include "src/compiler/bytecode-graph-builder.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/dead-code-elimination.h"
+#include "src/compiler/effect-control-linearizer.h"
 #include "src/compiler/escape-analysis-reducer.h"
 #include "src/compiler/escape-analysis.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-selector.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/js-builtin-reducer.h"
@@ skipping 186 matching lines @@
   void set_type_hint_analysis(TypeHintAnalysis* type_hint_analysis) {
     DCHECK_NULL(type_hint_analysis_);
     type_hint_analysis_ = type_hint_analysis;
   }
 
   Schedule* schedule() const { return schedule_; }
   void set_schedule(Schedule* schedule) {
     DCHECK(!schedule_);
     schedule_ = schedule;
   }
+  void reset_schedule() { schedule_ = nullptr; }
 
   Zone* instruction_zone() const { return instruction_zone_; }
   InstructionSequence* sequence() const { return sequence_; }
   Frame* frame() const { return frame_; }
 
   Zone* register_allocation_zone() const { return register_allocation_zone_; }
   RegisterAllocationData* register_allocation_data() const {
     return register_allocation_data_;
   }
 
@@ skipping 554 matching lines @@
 struct ControlFlowOptimizationPhase {
   static const char* phase_name() { return "control flow optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     ControlFlowOptimizer optimizer(data->graph(), data->common(),
                                    data->machine(), temp_zone);
     optimizer.Optimize();
   }
 };
 
+struct FixLowLevelEffectsPhase {

[Benedikt Meurer, 2016/04/18 04:34:18]

Can we have a single ControlEffectLinearizationPhase here, which does both the
scheduling and the actual linearization? using a temporary zone for the
schedule.

[Jarin, 2016/04/18 07:53:33]

Done.

+  static const char* phase_name() { return "low-level effect wiring"; }
+
+  void Run(PipelineData* data, Zone* temp_zone) {
+    EffectControlLinearizer introducer(data->jsgraph(), data->schedule(),
+                                       temp_zone);
+    introducer.Run();
+  }
+};
 
 struct ChangeLoweringPhase {
   static const char* phase_name() { return "change lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     JSGraphReducer graph_reducer(data->jsgraph(), temp_zone);
     DeadCodeElimination dead_code_elimination(&graph_reducer, data->graph(),
                                               data->common());
     SimplifiedOperatorReducer simple_reducer(data->jsgraph());
     ValueNumberingReducer value_numbering(temp_zone);
     ChangeLowering lowering(data->jsgraph());
     MachineOperatorReducer machine_reducer(data->jsgraph());
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->common(), data->machine());
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &simple_reducer);
     AddReducer(data, &graph_reducer, &value_numbering);
     AddReducer(data, &graph_reducer, &lowering);
     AddReducer(data, &graph_reducer, &machine_reducer);
     AddReducer(data, &graph_reducer, &common_reducer);
     graph_reducer.ReduceGraph();
   }
 };
 
+struct ComputeEffectSchedulePhase {
+  static const char* phase_name() { return "effect scheduling"; }
+
+  void Run(PipelineData* data, Zone* temp_zone) {
+    Schedule* schedule = Scheduler::ComputeSchedule(temp_zone, data->graph(),
+                                                    Scheduler::kNoFlags);
+    if (FLAG_turbo_verify) ScheduleVerifier::Run(schedule);
+    data->set_schedule(schedule);
+  }
+};
+
+struct EffectScheduleTrimmingPhase {

[Benedikt Meurer, 2016/04/18 04:34:18]

Can you put a TODO on this guy, that we only need to do this because the
scheduler is still confused by dead uses.

[Jarin, 2016/04/18 07:53:33]

Done.

+  static const char* phase_name() { return "effect schedule 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 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());
   }
 };
@@ skipping 408 matching lines @@
 
   if (FLAG_turbo_escape) {
     Run<EscapeAnalysisPhase>();
     RunPrintAndVerify("Escape Analysed");
   }
 
   // Lower simplified operators and insert changes.
   Run<SimplifiedLoweringPhase>();
   RunPrintAndVerify("Lowered simplified");
 
+  if (!info()->shared_info()->asm_function()) {

[Benedikt Meurer, 2016/04/18 04:34:18]

How bad is this actually for asm.js functions?

+    // TODO(jarin) Run value numbering for the representation changes.
+
+    // The scheduler requires the graphs to be trimmed, so trim now.
+    Run<EffectScheduleTrimmingPhase>();
+
+    // Schedule the graph without node splitting so that we can
+    // fix the effect and control flow for nodes with low-level side
+    // effects (such as changing representation to tagged or
+    // 'floating' allocation regions.)
+    Run<ComputeEffectSchedulePhase>();
+
+    // Post-pass for wiring the control/effects
+    // - connect allocating representation changes into the control&effect
+    //   chains and lower them,
+    // - get rid of the region markers,
+    // - introduce effect phis and rewire effects to get SSA again.
+    Run<FixLowLevelEffectsPhase>();
+
+    // Get rid of the schedule.
+    // TODO(jarin) We should produce the schedule in a temporary zone.
+    data.reset_schedule();
+    RunPrintAndVerify("Fixed state flow");
+  }
+
   Run<BranchEliminationPhase>();
   RunPrintAndVerify("Branch conditions eliminated");
 
   // Optimize control flow.
   if (FLAG_turbo_cf_optimization) {
     Run<ControlFlowOptimizationPhase>();
     RunPrintAndVerify("Control flow optimized");
   }
 
   // Lower changes that have been inserted before.
@@ skipping 300 matching lines @@
   }
 
   data->DeleteRegisterAllocationZone();
 }
 
 Isolate* Pipeline::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8