[heap] Move hash_seed into RO_SPACE

Creates the hash_seed byte array in RO_SPACE and moves the root from
STRONG_MUTABLE_IMMOVABLE_ROOT_LIST to STRONG_READ_ONLY_ROOT_LIST.

Bug: v8:8191
Change-Id: I3b044fbb3e51eb5d21ac2e68a54076623865b9d2
Reviewed-on: https://chromium-review.googlesource.com/c/1297959
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56960}

src/heap/heap-inl.h

@@ -555,7 +555,8 @@ Oddball* Heap::ToBoolean(bool condition) {
 
 uint64_t Heap::HashSeed() {
   uint64_t seed;
-  hash_seed()->copy_out(0, reinterpret_cast<byte*>(&seed), kInt64Size);
+  ReadOnlyRoots(this).hash_seed()->copy_out(0, reinterpret_cast<byte*>(&seed),
+                                            kInt64Size);
   DCHECK(FLAG_randomize_hashes || seed == 0);
   return seed;
 }

src/heap/heap.cc

@@ -4413,6 +4413,7 @@ void Heap::SetUp() {
 }
 
 void Heap::InitializeHashSeed() {
+  DCHECK(!deserialization_complete_);
   uint64_t new_hash_seed;
   if (FLAG_hash_seed == 0) {
     int64_t rnd = isolate()->random_number_generator()->NextInt64();
@@ -4420,7 +4421,8 @@ void Heap::InitializeHashSeed() {
   } else {
     new_hash_seed = static_cast<uint64_t>(FLAG_hash_seed);
   }
-  hash_seed()->copy_in(0, reinterpret_cast<byte*>(&new_hash_seed), kInt64Size);
+  ReadOnlyRoots(this).hash_seed()->copy_in(
+      0, reinterpret_cast<byte*>(&new_hash_seed), kInt64Size);
 }
 
 void Heap::SetStackLimits() {

src/heap/setup-heap-internal.cc

@@ -623,7 +623,7 @@ void Heap::CreateInitialObjects() {
   set_minus_infinity_value(
       *factory->NewHeapNumber(-V8_INFINITY, TENURED_READ_ONLY));
 
-  set_hash_seed(*factory->NewByteArray(kInt64Size, TENURED));
+  set_hash_seed(*factory->NewByteArray(kInt64Size, TENURED_READ_ONLY));
   InitializeHashSeed();
 
   // There's no "current microtask" in the beginning.

src/roots.h

@@ -215,7 +215,9 @@ class RootVisitor;
   V(HeapObject*, self_reference_marker, SelfReferenceMarker)                   \
   /* Canonical trampoline RelocInfo */                                         \
   V(ByteArray*, off_heap_trampoline_relocation_info,                           \
-    OffHeapTrampolineRelocationInfo)
+    OffHeapTrampolineRelocationInfo)                                           \
+  /* Hash seed */                                                              \
+  V(ByteArray*, hash_seed, HashSeed)
 
 // Mutable roots that are known to be immortal immovable, for which we can
 // safely skip write barriers.
@@ -253,8 +255,6 @@ class RootVisitor;
   V(MicrotaskQueue*, default_microtask_queue, DefaultMicrotaskQueue)          \
   /* Indirection lists for isolate-independent builtins */                    \
   V(FixedArray*, builtins_constants_table, BuiltinsConstantsTable)            \
-  /* Hash seed */                                                             \
-  V(ByteArray*, hash_seed, HashSeed)                                          \
   /* JS Entries */                                                            \
   V(Code*, js_entry_code, JsEntryCode)                                        \
   V(Code*, js_construct_entry_code, JsConstructEntryCode)                     \

tools/v8heapconst.py

@@ -296,41 +296,41 @@ KNOWN_MAPS = {
   ("RO_SPACE", 0x02699): (171, "Tuple2Map"),
   ("RO_SPACE", 0x02739): (173, "ArrayBoilerplateDescriptionMap"),
   ("RO_SPACE", 0x02a79): (161, "InterceptorInfoMap"),
-  ("RO_SPACE", 0x050c1): (153, "AccessCheckInfoMap"),
-  ("RO_SPACE", 0x05111): (154, "AccessorInfoMap"),
-  ("RO_SPACE", 0x05161): (155, "AccessorPairMap"),
-  ("RO_SPACE", 0x051b1): (156, "AliasedArgumentsEntryMap"),
-  ("RO_SPACE", 0x05201): (157, "AllocationMementoMap"),
-  ("RO_SPACE", 0x05251): (158, "AsyncGeneratorRequestMap"),
-  ("RO_SPACE", 0x052a1): (159, "DebugInfoMap"),
-  ("RO_SPACE", 0x052f1): (160, "FunctionTemplateInfoMap"),
-  ("RO_SPACE", 0x05341): (162, "InterpreterDataMap"),
-  ("RO_SPACE", 0x05391): (163, "ModuleInfoEntryMap"),
-  ("RO_SPACE", 0x053e1): (164, "ModuleMap"),
-  ("RO_SPACE", 0x05431): (165, "ObjectTemplateInfoMap"),
-  ("RO_SPACE", 0x05481): (166, "PromiseCapabilityMap"),
-  ("RO_SPACE", 0x054d1): (167, "PromiseReactionMap"),
-  ("RO_SPACE", 0x05521): (168, "PrototypeInfoMap"),
-  ("RO_SPACE", 0x05571): (169, "ScriptMap"),
-  ("RO_SPACE", 0x055c1): (170, "StackFrameInfoMap"),
-  ("RO_SPACE", 0x05611): (172, "Tuple3Map"),
-  ("RO_SPACE", 0x05661): (174, "WasmDebugInfoMap"),
-  ("RO_SPACE", 0x056b1): (175, "WasmExportedFunctionDataMap"),
-  ("RO_SPACE", 0x05701): (176, "CallableTaskMap"),
-  ("RO_SPACE", 0x05751): (177, "CallbackTaskMap"),
-  ("RO_SPACE", 0x057a1): (178, "PromiseFulfillReactionJobTaskMap"),
-  ("RO_SPACE", 0x057f1): (179, "PromiseRejectReactionJobTaskMap"),
-  ("RO_SPACE", 0x05841): (180, "PromiseResolveThenableJobTaskMap"),
-  ("RO_SPACE", 0x05891): (181, "MicrotaskQueueMap"),
-  ("RO_SPACE", 0x058e1): (182, "AllocationSiteWithWeakNextMap"),
-  ("RO_SPACE", 0x05931): (182, "AllocationSiteWithoutWeakNextMap"),
-  ("RO_SPACE", 0x05981): (214, "LoadHandler1Map"),
-  ("RO_SPACE", 0x059d1): (214, "LoadHandler2Map"),
-  ("RO_SPACE", 0x05a21): (214, "LoadHandler3Map"),
-  ("RO_SPACE", 0x05a71): (221, "StoreHandler0Map"),
-  ("RO_SPACE", 0x05ac1): (221, "StoreHandler1Map"),
-  ("RO_SPACE", 0x05b11): (221, "StoreHandler2Map"),
-  ("RO_SPACE", 0x05b61): (221, "StoreHandler3Map"),
+  ("RO_SPACE", 0x050d9): (153, "AccessCheckInfoMap"),
+  ("RO_SPACE", 0x05129): (154, "AccessorInfoMap"),
+  ("RO_SPACE", 0x05179): (155, "AccessorPairMap"),
+  ("RO_SPACE", 0x051c9): (156, "AliasedArgumentsEntryMap"),
+  ("RO_SPACE", 0x05219): (157, "AllocationMementoMap"),
+  ("RO_SPACE", 0x05269): (158, "AsyncGeneratorRequestMap"),
+  ("RO_SPACE", 0x052b9): (159, "DebugInfoMap"),
+  ("RO_SPACE", 0x05309): (160, "FunctionTemplateInfoMap"),
+  ("RO_SPACE", 0x05359): (162, "InterpreterDataMap"),
+  ("RO_SPACE", 0x053a9): (163, "ModuleInfoEntryMap"),
+  ("RO_SPACE", 0x053f9): (164, "ModuleMap"),
+  ("RO_SPACE", 0x05449): (165, "ObjectTemplateInfoMap"),
+  ("RO_SPACE", 0x05499): (166, "PromiseCapabilityMap"),
+  ("RO_SPACE", 0x054e9): (167, "PromiseReactionMap"),
+  ("RO_SPACE", 0x05539): (168, "PrototypeInfoMap"),
+  ("RO_SPACE", 0x05589): (169, "ScriptMap"),
+  ("RO_SPACE", 0x055d9): (170, "StackFrameInfoMap"),
+  ("RO_SPACE", 0x05629): (172, "Tuple3Map"),
+  ("RO_SPACE", 0x05679): (174, "WasmDebugInfoMap"),
+  ("RO_SPACE", 0x056c9): (175, "WasmExportedFunctionDataMap"),
+  ("RO_SPACE", 0x05719): (176, "CallableTaskMap"),
+  ("RO_SPACE", 0x05769): (177, "CallbackTaskMap"),
+  ("RO_SPACE", 0x057b9): (178, "PromiseFulfillReactionJobTaskMap"),
+  ("RO_SPACE", 0x05809): (179, "PromiseRejectReactionJobTaskMap"),
+  ("RO_SPACE", 0x05859): (180, "PromiseResolveThenableJobTaskMap"),
+  ("RO_SPACE", 0x058a9): (181, "MicrotaskQueueMap"),
+  ("RO_SPACE", 0x058f9): (182, "AllocationSiteWithWeakNextMap"),
+  ("RO_SPACE", 0x05949): (182, "AllocationSiteWithoutWeakNextMap"),
+  ("RO_SPACE", 0x05999): (214, "LoadHandler1Map"),
+  ("RO_SPACE", 0x059e9): (214, "LoadHandler2Map"),
+  ("RO_SPACE", 0x05a39): (214, "LoadHandler3Map"),
+  ("RO_SPACE", 0x05a89): (221, "StoreHandler0Map"),
+  ("RO_SPACE", 0x05ad9): (221, "StoreHandler1Map"),
+  ("RO_SPACE", 0x05b29): (221, "StoreHandler2Map"),
+  ("RO_SPACE", 0x05b79): (221, "StoreHandler3Map"),
   ("MAP_SPACE", 0x00139): (1057, "ExternalMap"),
   ("MAP_SPACE", 0x00189): (1073, "JSMessageObjectMap"),
 }
@@ -385,6 +385,7 @@ KNOWN_OBJECTS = {
   ("RO_SPACE", 0x02b01): "MinusInfinityValue",
   ("RO_SPACE", 0x02b11): "SelfReferenceMarker",
   ("RO_SPACE", 0x02b69): "OffHeapTrampolineRelocationInfo",
+  ("RO_SPACE", 0x02b81): "HashSeed",
   ("OLD_SPACE", 0x00139): "ArgumentsIteratorAccessor",
   ("OLD_SPACE", 0x001a9): "ArrayLengthAccessor",
   ("OLD_SPACE", 0x00219): "BoundFunctionLengthAccessor",
@@ -419,7 +420,6 @@ KNOWN_OBJECTS = {
   ("OLD_SPACE", 0x018c1): "RegExpMultipleCache",
   ("OLD_SPACE", 0x020d1): "DefaultMicrotaskQueue",
   ("OLD_SPACE", 0x020e9): "BuiltinsConstantsTable",
-  ("OLD_SPACE", 0x02a11): "HashSeed",
 }
 
 # List of known V8 Frame Markers.