[turbofan] Remove JSInliningHeuristic::Mode

This enum defined three modes of doing inlining:
kGeneralInlining, kRestrictedInlining, kStressInlining.
kStressInlining was unused. kRestrictedInlining meant
that JSInliningHeuristic::Reduce would return NoChange,
but only after wasting some time inspecting calls. This
is now replaced by simply not installing JSInliningHeuristic
as a reducer when inlining is disabled.

Note: There is still a --stress-inline flag, which sets
(through flag implications) a bunch of parameters that affect
inlining.

Change-Id: I05bafbe3f1f35610d7035a2c71c5ac17bdb80758
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1936473
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65196}

src/compiler/js-inlining-heuristic.cc

@@ -131,8 +131,7 @@ Reduction JSInliningHeuristic::Reduce(Node* node) {
 
   if (!IrOpcode::IsInlineeOpcode(node->opcode())) return NoChange();
 
-  if (total_inlined_bytecode_size_ >= FLAG_max_inlined_bytecode_size_absolute &&
-      mode_ != kStressInlining) {
+  if (total_inlined_bytecode_size_ >= FLAG_max_inlined_bytecode_size_absolute) {
     return NoChange();
   }
 
@@ -201,18 +200,6 @@ Reduction JSInliningHeuristic::Reduce(Node* node) {
     candidate.frequency = p.frequency();
   }
 
-  // Handling of special inlining modes right away:
-  //  - For restricted inlining: stop all handling at this point.
-  //  - For stressing inlining: immediately handle all functions.
-  switch (mode_) {
-    case kRestrictedInlining:
-      return NoChange();
-    case kStressInlining:
-      return InlineCandidate(candidate, false);
-    case kGeneralInlining:
-      break;
-  }
-
   // Don't consider a {candidate} whose frequency is below the
   // threshold, i.e. a call site that is only hit once every N
   // invocations of the caller.

src/compiler/js-inlining-heuristic.h

@@ -13,13 +13,11 @@ namespace compiler {
 
 class JSInliningHeuristic final : public AdvancedReducer {
  public:
-  enum Mode { kGeneralInlining, kRestrictedInlining, kStressInlining };
-  JSInliningHeuristic(Editor* editor, Mode mode, Zone* local_zone,
+  JSInliningHeuristic(Editor* editor, Zone* local_zone,
                       OptimizedCompilationInfo* info, JSGraph* jsgraph,
                       JSHeapBroker* broker,
                       SourcePositionTable* source_positions)
       : AdvancedReducer(editor),
-        mode_(mode),
         inliner_(editor, local_zone, info, jsgraph, broker, source_positions),
         candidates_(local_zone),
         seen_(local_zone),
@@ -90,7 +88,6 @@ class JSInliningHeuristic final : public AdvancedReducer {
   Isolate* isolate() const { return jsgraph_->isolate(); }
   SimplifiedOperatorBuilder* simplified() const;
 
-  Mode const mode_;
   JSInliner inliner_;
   Candidates candidates_;
   ZoneSet<NodeId> seen_;

src/compiler/pipeline.cc

@@ -1308,9 +1308,6 @@ struct InliningPhase {
         &graph_reducer, data->jsgraph(), data->broker(), flags,
         data->dependencies(), temp_zone, info->zone());
     JSInliningHeuristic inlining(&graph_reducer,
-                                 data->info()->is_inlining_enabled()
-                                     ? JSInliningHeuristic::kGeneralInlining
-                                     : JSInliningHeuristic::kRestrictedInlining,
                                  temp_zone, data->info(), data->jsgraph(),
                                  data->broker(), data->source_positions());
     JSIntrinsicLowering intrinsic_lowering(&graph_reducer, data->jsgraph(),
@@ -1322,7 +1319,9 @@ struct InliningPhase {
     AddReducer(data, &graph_reducer, &context_specialization);
     AddReducer(data, &graph_reducer, &intrinsic_lowering);
     AddReducer(data, &graph_reducer, &call_reducer);
-    AddReducer(data, &graph_reducer, &inlining);
+    if (data->info()->is_inlining_enabled()) {
+      AddReducer(data, &graph_reducer, &inlining);
+    }
     graph_reducer.ReduceGraph();
   }
 };