[turbofan] Effect linearization after representation inference.

src/compiler/pipeline.cc

Index: src/compiler/pipeline.cc
diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index d711abefb8338ead3c661268696013612f3a1253..b84a5d0af70f876e6bb5bde15215da20b1456527 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -19,6 +19,7 @@
 #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"
@@ -225,6 +226,7 @@ class PipelineData {
     DCHECK(!schedule_);
     schedule_ = schedule;
   }
+  void reset_schedule() { schedule_ = nullptr; }
 
   Zone* instruction_zone() const { return instruction_zone_; }
   InstructionSequence* sequence() const { return sequence_; }
@@ -799,6 +801,15 @@ struct ControlFlowOptimizationPhase {
   }
 };
 
+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"; }
@@ -823,6 +834,26 @@ struct ChangeLoweringPhase {
   }
 };
 
+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"; }
@@ -1251,6 +1282,31 @@ Handle<Code> Pipeline::GenerateCode() {
   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");