Bookkeeping for allocation site pretenuring

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 6ef871fe669bf66e9d14234c1f72645fb9ca8d7f..f07fdfb87d42a6525eb8282542488b3f9e6360a6 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -1792,6 +1792,14 @@ 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;
+  }
+
   __ mov(a0, result_register());
   __ lw(a3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ lw(a3, FieldMemOperand(a3, JSFunction::kLiteralsOffset));
@@ -1801,7 +1809,7 @@ 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(isolate()->counters()->cow_arrays_created_stub(),
@@ -1815,12 +1823,9 @@ 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);