[literals] Migrate deprecated sub-literals on the first run

It might happen that we deprecate the map of previous sub-literals if we create
literals with the same map several times. This is usually the case for
configuration arrays.

Bug: chromium:734051
Change-Id: I82284e5aae632286135b2092816d776d229c65af
Reviewed-on: https://chromium-review.googlesource.com/538665Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46003}

src/allocation-site-scopes.h

@@ -11,6 +11,24 @@
 namespace v8 {
 namespace internal {
 
+class DeprecationUpdateContext {
+ public:
+  explicit DeprecationUpdateContext(Isolate* isolate) { isolate_ = isolate; }
+  Isolate* isolate() { return isolate_; }
+  bool ShouldCreateMemento(Handle<JSObject> object) { return false; }
+  inline void ExitScope(Handle<AllocationSite> scope_site,
+                        Handle<JSObject> object) {}
+  Handle<AllocationSite> EnterNewScope() { return Handle<AllocationSite>(); }
+  Handle<AllocationSite> current() {
+    UNREACHABLE();
+    return Handle<AllocationSite>();
+  }
+
+  static const bool kCopying = false;
+
+ private:
+  Isolate* isolate_;
+};
 
 // AllocationSiteContext is the base class for walking and copying a nested
 // boilerplate with AllocationSite and AllocationMemento support.

src/objects.cc

@@ -8050,6 +8050,14 @@ MaybeHandle<JSObject> JSObjectWalkVisitor<ContextObject>::StructureWalk(
   return copy;
 }
 
+MaybeHandle<JSObject> JSObject::DeepWalk(
+    Handle<JSObject> object, DeprecationUpdateContext* site_context) {
+  JSObjectWalkVisitor<DeprecationUpdateContext> v(site_context, kNoHints);
+  MaybeHandle<JSObject> result = v.StructureWalk(object);
+  Handle<JSObject> for_assert;
+  DCHECK(!result.ToHandle(&for_assert) || for_assert.is_identical_to(object));
+  return result;
+}
 
 MaybeHandle<JSObject> JSObject::DeepWalk(
     Handle<JSObject> object,

src/objects.h

@@ -930,6 +930,7 @@ class AllocationSiteCreationContext;
 class AllocationSiteUsageContext;
 class Cell;
 class ConsString;
+class DeprecationUpdateContext;
 class ElementsAccessor;
 class FindAndReplacePattern;
 class FixedArrayBase;
@@ -2502,6 +2503,8 @@ class JSObject: public JSReceiver {
   MUST_USE_RESULT static MaybeHandle<JSObject> DeepWalk(
       Handle<JSObject> object,
       AllocationSiteCreationContext* site_context);
+  MUST_USE_RESULT static MaybeHandle<JSObject> DeepWalk(
+      Handle<JSObject> object, DeprecationUpdateContext* site_context);
 
   DECLARE_CAST(JSObject)
 

src/runtime/runtime-literals.cc

@@ -208,6 +208,12 @@ MaybeHandle<JSObject> CreateLiteral(Isolate* isolate,
     boilerplate = Boilerplate::Create(isolate, vector, description, flags);
     if (IsUninitializedLiteralSite(literal_site)) {
       PreInitializeLiteralSite(vector, literals_slot);
+      if (copy_hints == JSObject::kNoHints) {
+        DeprecationUpdateContext update_context(isolate);
+        RETURN_ON_EXCEPTION(isolate,
+                            JSObject::DeepWalk(boilerplate, &update_context),
+                            JSObject);
+      }
       return boilerplate;
     }
     // Install AllocationSite objects.

test/mjsunit/allocation-site-info.js

@@ -637,3 +637,48 @@ gc();
     assertKind(elements_kind.fast_double, [instance.a, instance.b]);
   }
 })();
+
+(function TestInnerBoilerplateMapDeprecation() {
+  // Create a literal where the inner literals cause a map deprecation of the
+  // previous inner literal.
+  function literal() {
+    return [
+    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1,   b: 2, c: 3, d: 4.1},
+
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1},
+    {xA2A:false, a: 1.1, b: 2, c: 3, d: 4.1}
+    ];
+  };
+  let instance = literal();
+
+  // Make sure all sub-literals are migrated properly.
+  for (let i = 0; i < instance.length; i++) {
+    let sub_literal = instance[i];
+    assertKind(elements_kind.fast_double, [sub_literal.a]);
+    assertKind(elements_kind.fast_smi_only, [sub_literal.b]);
+    assertKind(elements_kind.fast_smi_only, [sub_literal.c]);
+    assertKind(elements_kind.fast_double, [sub_literal.d]);
+  }
+
+  instance = literal();
+  instance = literal();
+  instance = literal();
+  for (let i = 0; i < instance.length; i++) {
+    let sub_literal = instance[i];
+    assertKind(elements_kind.fast_double, [sub_literal.a]);
+    assertKind(elements_kind.fast_smi_only, [sub_literal.b]);
+    assertKind(elements_kind.fast_smi_only, [sub_literal.c]);
+    assertKind(elements_kind.fast_double, [sub_literal.d]);
+  }
+})();