[turbofan] Make {JumpThreading} independent of Isolate.

R=clemensh@chromium.org

Change-Id: I1045885ad1efe2b1dd7a9e2b83d1f5323e77dcbb
Reviewed-on: https://chromium-review.googlesource.com/1134988Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54403}

src/compiler/jump-threading.cc

@@ -155,13 +155,12 @@ bool JumpThreading::ComputeForwarding(Zone* local_zone,
   return state.forwarded;
 }
 
-
-void JumpThreading::ApplyForwarding(ZoneVector<RpoNumber>& result,
+void JumpThreading::ApplyForwarding(Zone* local_zone,
+                                    ZoneVector<RpoNumber>& result,
                                     InstructionSequence* code) {
   if (!FLAG_turbo_jt) return;
 
-  Zone local_zone(code->isolate()->allocator(), ZONE_NAME);
-  ZoneVector<bool> skip(static_cast<int>(result.size()), false, &local_zone);
+  ZoneVector<bool> skip(static_cast<int>(result.size()), false, local_zone);
 
   // Skip empty blocks when the previous block doesn't fall through.
   bool prev_fallthru = true;

src/compiler/jump-threading.h

@@ -22,7 +22,8 @@ class JumpThreading {
 
   // Rewrite the instructions to forward jumps and branches.
   // May also negate some branches.
-  static void ApplyForwarding(ZoneVector<RpoNumber>& forwarding,
+  static void ApplyForwarding(Zone* local_zone,
+                              ZoneVector<RpoNumber>& forwarding,
                               InstructionSequence* code);
 };
 

src/compiler/pipeline.cc

@@ -1852,7 +1852,7 @@ struct JumpThreadingPhase {
     ZoneVector<RpoNumber> result(temp_zone);
     if (JumpThreading::ComputeForwarding(temp_zone, result, data->sequence(),
                                          frame_at_start)) {
-      JumpThreading::ApplyForwarding(result, data->sequence());
+      JumpThreading::ApplyForwarding(temp_zone, result, data->sequence());
     }
   }
 };

test/cctest/compiler/test-jump-threading.cc

@@ -617,7 +617,7 @@ void ApplyForwarding(TestCode& code, int size, int* forward) {
   for (int i = 0; i < size; i++) {
     vector.push_back(RpoNumber::FromInt(forward[i]));
   }
-  JumpThreading::ApplyForwarding(vector, &code.sequence_);
+  JumpThreading::ApplyForwarding(code.main_zone(), vector, &code.sequence_);
 }