[turbofan] Allow tests to enable/disable instruction scheduling.

Some instruction selection tests rely on the instructions to be emitted
in a specific order.

R=jarin@chromium.org, bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2276003002
Cr-Commit-Position: refs/heads/master@{#38886}

src/compiler/instruction-selector.cc

@@ -22,7 +22,8 @@ InstructionSelector::InstructionSelector(
     Zone* zone, size_t node_count, Linkage* linkage,
     InstructionSequence* sequence, Schedule* schedule,
     SourcePositionTable* source_positions, Frame* frame,
-    SourcePositionMode source_position_mode, Features features)
+    SourcePositionMode source_position_mode, Features features,
+    EnableScheduling enable_scheduling)
     : zone_(zone),
       linkage_(linkage),
       sequence_(sequence),
@@ -38,6 +39,7 @@ InstructionSelector::InstructionSelector(
       virtual_registers_(node_count,
                          InstructionOperand::kInvalidVirtualRegister, zone),
       scheduler_(nullptr),
+      enable_scheduling_(enable_scheduling),
       frame_(frame) {
   instructions_.reserve(node_count);
 }
@@ -65,8 +67,7 @@ void InstructionSelector::SelectInstructions() {
   }
 
   // Schedule the selected instructions.
-  if (FLAG_turbo_instruction_scheduling &&
-      InstructionScheduler::SchedulerSupported()) {
+  if (UseInstructionScheduling()) {
     scheduler_ = new (zone()) InstructionScheduler(zone(), sequence());
   }
 
@@ -88,8 +89,7 @@ void InstructionSelector::SelectInstructions() {
 }
 
 void InstructionSelector::StartBlock(RpoNumber rpo) {
-  if (FLAG_turbo_instruction_scheduling &&
-      InstructionScheduler::SchedulerSupported()) {
+  if (UseInstructionScheduling()) {
     DCHECK_NOT_NULL(scheduler_);
     scheduler_->StartBlock(rpo);
   } else {
@@ -99,8 +99,7 @@ void InstructionSelector::StartBlock(RpoNumber rpo) {
 
 
 void InstructionSelector::EndBlock(RpoNumber rpo) {
-  if (FLAG_turbo_instruction_scheduling &&
-      InstructionScheduler::SchedulerSupported()) {
+  if (UseInstructionScheduling()) {
     DCHECK_NOT_NULL(scheduler_);
     scheduler_->EndBlock(rpo);
   } else {
@@ -110,8 +109,7 @@ void InstructionSelector::EndBlock(RpoNumber rpo) {
 
 
 void InstructionSelector::AddInstruction(Instruction* instr) {
-  if (FLAG_turbo_instruction_scheduling &&
-      InstructionScheduler::SchedulerSupported()) {
+  if (UseInstructionScheduling()) {
     DCHECK_NOT_NULL(scheduler_);
     scheduler_->AddInstruction(instr);
   } else {

src/compiler/instruction-selector.h

@@ -48,13 +48,17 @@ class InstructionSelector final {
   class Features;
 
   enum SourcePositionMode { kCallSourcePositions, kAllSourcePositions };
+  enum EnableScheduling { kDisableScheduling, kEnableScheduling };
 
   InstructionSelector(
       Zone* zone, size_t node_count, Linkage* linkage,
       InstructionSequence* sequence, Schedule* schedule,
       SourcePositionTable* source_positions, Frame* frame,
       SourcePositionMode source_position_mode = kCallSourcePositions,
-      Features features = SupportedFeatures());
+      Features features = SupportedFeatures(),
+      EnableScheduling enable_scheduling = FLAG_turbo_instruction_scheduling
+                                               ? kEnableScheduling
+                                               : kDisableScheduling);
 
   // Visit code for the entire graph with the included schedule.
   void SelectInstructions();
@@ -199,6 +203,11 @@ class InstructionSelector final {
  private:
   friend class OperandGenerator;
 
+  bool UseInstructionScheduling() const {
+    return (enable_scheduling_ == kEnableScheduling) &&
+           InstructionScheduler::SchedulerSupported();
+  }
+
   void EmitTableSwitch(const SwitchInfo& sw, InstructionOperand& index_operand);
   void EmitLookupSwitch(const SwitchInfo& sw,
                         InstructionOperand& value_operand);
@@ -333,6 +342,7 @@ class InstructionSelector final {
   IntVector effect_level_;
   IntVector virtual_registers_;
   InstructionScheduler* scheduler_;
+  EnableScheduling enable_scheduling_;
   Frame* frame_;
 };
 

test/unittests/compiler/instruction-selector-unittest.cc

@@ -41,7 +41,8 @@ InstructionSelectorTest::Stream InstructionSelectorTest::StreamBuilder::Build(
   SourcePositionTable source_position_table(graph());
   InstructionSelector selector(test_->zone(), node_count, &linkage, &sequence,
                                schedule, &source_position_table, nullptr,
-                               source_position_mode, features);
+                               source_position_mode, features,
+                               InstructionSelector::kDisableScheduling);
   selector.SelectInstructions();
   if (FLAG_trace_turbo) {
     OFStream out(stdout);