Bookkeeping for allocation site pretenuring

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 15bfba3ce61c4454586e6d776833eb975b93109c..17139c1704b50cc17ca23cc6b9850e168fdea648 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -1784,6 +1784,14 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   Handle<FixedArrayBase> constant_elements_values(
       FixedArrayBase::cast(constant_elements->get(1)));
 
+  AllocationSiteMode allocation_site_mode = FLAG_track_allocation_sites
+      ? TRACK_ALLOCATION_SITE : DONT_TRACK_ALLOCATION_SITE;
+  if (has_constant_fast_elements && !FLAG_allocation_site_pretenuring) {
+    // If the only customer of allocation sites is transitioning, then
+    // we can turn it off if we don't have anywhere else to transition to.
+    allocation_site_mode = DONT_TRACK_ALLOCATION_SITE;
+  }
+
   __ ldr(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r3, FieldMemOperand(r3, JSFunction::kLiteralsOffset));
   __ mov(r2, Operand(Smi::FromInt(expr->literal_index())));
@@ -1792,7 +1800,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
       isolate()->heap()->fixed_cow_array_map()) {
     FastCloneShallowArrayStub stub(
         FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS,
-        DONT_TRACK_ALLOCATION_SITE,
+        allocation_site_mode,
         length);
     __ CallStub(&stub);
     __ IncrementCounter(
@@ -1807,12 +1815,9 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
            FLAG_smi_only_arrays);
     FastCloneShallowArrayStub::Mode mode =
         FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS;
-    AllocationSiteMode allocation_site_mode = FLAG_track_allocation_sites
-        ? TRACK_ALLOCATION_SITE : DONT_TRACK_ALLOCATION_SITE;
 
     if (has_fast_elements) {
       mode = FastCloneShallowArrayStub::CLONE_ELEMENTS;
-      allocation_site_mode = DONT_TRACK_ALLOCATION_SITE;
     }
 
     FastCloneShallowArrayStub stub(mode, allocation_site_mode, length);