[wasm] further simplification of WasmCompiledModule

Calculate memory size from the available heap. This avoids
the bugs due to some numbers being stored as objects (by-ref)
and thus needing special handling when cloning.

This leaves all the rest of the numbers as read-only.

Further simplified by representing globals size as a Smi.

BUG=

Review-Url: https://codereview.chromium.org/2381393002
Cr-Commit-Position: refs/heads/master@{#39923}

src/wasm/wasm-module.cc

@@ -852,7 +852,8 @@ static void ResetCompiledModule(Isolate* isolate, JSObject* owner,
                                 WasmCompiledModule* compiled_module) {
   Object* undefined = *isolate->factory()->undefined_value();
   uint32_t old_mem_size = compiled_module->mem_size();
-  Object* mem_start = compiled_module->ptr_to_mem_start();
+  uint32_t default_mem_size = compiled_module->default_mem_size();
+  Object* mem_start = compiled_module->ptr_to_heap();
   Address old_mem_address = nullptr;
   Address globals_start =
       GetGlobalStartAddressFromCodeTemplate(undefined, owner);
@@ -877,8 +878,8 @@ static void ResetCompiledModule(Isolate* isolate, JSObject* owner,
         RelocInfo::Mode mode = it.rinfo()->rmode();
         if (RelocInfo::IsWasmMemoryReference(mode) ||
             RelocInfo::IsWasmMemorySizeReference(mode)) {
-          it.rinfo()->update_wasm_memory_reference(old_mem_address, nullptr,
-                                                   old_mem_size, old_mem_size);
+          it.rinfo()->update_wasm_memory_reference(
+              old_mem_address, nullptr, old_mem_size, default_mem_size);
           changed = true;
         } else {
           CHECK(RelocInfo::IsWasmGlobalReference(mode));
@@ -893,7 +894,7 @@ static void ResetCompiledModule(Isolate* isolate, JSObject* owner,
     }
   }
   compiled_module->reset_weak_owning_instance();
-  compiled_module->reset_mem_start();
+  compiled_module->reset_heap();
 }
 
 static void InstanceFinalizer(const v8::WeakCallbackInfo<void>& data) {
@@ -1050,7 +1051,8 @@ MaybeHandle<WasmCompiledModule> WasmModule::CompileFunctions(
   // and information needed at instantiation time. This object needs to be
   // serializable. Instantiation may occur off a deserialized version of this
   // object.
-  Handle<WasmCompiledModule> ret = WasmCompiledModule::New(isolate);
+  Handle<WasmCompiledModule> ret = WasmCompiledModule::New(
+      isolate, min_mem_pages, globals_size, mem_export, origin);
   ret->set_code_table(code_table);
   if (!indirect_table.is_null()) {
     ret->set_indirect_function_tables(indirect_table.ToHandleChecked());
@@ -1124,12 +1126,8 @@ MaybeHandle<WasmCompiledModule> WasmModule::CompileFunctions(
   Handle<ByteArray> function_name_table =
       BuildFunctionNamesTable(isolate, module_env.module);
   ret->set_function_names(function_name_table);
-  ret->set_min_required_memory(min_mem_pages);
   if (data_segments.size() > 0) SaveDataSegmentInfo(factory, this, ret);
-  ret->set_globals_size(globals_size);
-  ret->set_export_memory(mem_export);
-  ret->set_origin(origin);
-  ret->set_mem_size(temp_instance.mem_size);
+  DCHECK_EQ(ret->default_mem_size(), temp_instance.mem_size);
   return ret;
 }
 
@@ -1249,7 +1247,6 @@ MaybeHandle<JSObject> WasmModule::Instantiate(Isolate* isolate,
             UNREACHABLE();
         }
       }
-      compiled_module->set_mem_size(original->mem_size());
       RecordStats(isolate, code_table);
     } else {
       // There was no owner, so we can reuse the original.
@@ -1273,7 +1270,7 @@ MaybeHandle<JSObject> WasmModule::Instantiate(Isolate* isolate,
   MaybeHandle<JSArrayBuffer> old_memory;
   // TODO(titzer): handle imported memory properly.
 
-  uint32_t min_mem_pages = compiled_module->min_required_memory();
+  uint32_t min_mem_pages = compiled_module->min_memory_pages();
   isolate->counters()->wasm_min_mem_pages_count()->AddSample(min_mem_pages);
   // TODO(wasm): re-enable counter for max_mem_pages when we use that field.
 
@@ -1288,16 +1285,16 @@ MaybeHandle<JSObject> WasmModule::Instantiate(Isolate* isolate,
     uint32_t mem_size = static_cast<uint32_t>(memory->byte_length()->Number());
     LoadDataSegments(compiled_module, mem_start, mem_size);
 
-    uint32_t old_mem_size = compiled_module->mem_size();
+    uint32_t old_mem_size = compiled_module->has_heap()
+                                ? compiled_module->mem_size()
+                                : compiled_module->default_mem_size();
     Address old_mem_start =
-        compiled_module->has_mem_start()
-            ? static_cast<Address>(
-                  compiled_module->mem_start()->backing_store())
+        compiled_module->has_heap()
+            ? static_cast<Address>(compiled_module->heap()->backing_store())
             : nullptr;
     RelocateInstanceCode(instance, old_mem_start, mem_start, old_mem_size,
                          mem_size);
-    compiled_module->set_mem_size(mem_size);
-    compiled_module->set_mem_start(memory);
+    compiled_module->set_heap(memory);
   }
 
   //--------------------------------------------------------------------------
@@ -1537,6 +1534,26 @@ MaybeHandle<JSObject> WasmModule::Instantiate(Isolate* isolate,
   return instance;
 }
 
+Handle<WasmCompiledModule> WasmCompiledModule::New(Isolate* isolate,
+                                                   uint32_t min_memory_pages,
+                                                   uint32_t globals_size,
+                                                   bool export_memory,
+                                                   ModuleOrigin origin) {
+  Handle<FixedArray> ret =
+      isolate->factory()->NewFixedArray(PropertyIndices::Count, TENURED);
+  // Globals size is expected to fit into an int without overflow. This is not
+  // supported by the spec at the moment, however, we don't support array
+  // buffer sizes over 1g, so, for now, we avoid alocating a HeapNumber for
+  // the globals size. The CHECK guards this assumption.
+  CHECK_GE(static_cast<int>(globals_size), 0);
+  ret->set(kID_min_memory_pages,
+           Smi::FromInt(static_cast<int>(min_memory_pages)));
+  ret->set(kID_globals_size, Smi::FromInt(static_cast<int>(globals_size)));
+  ret->set(kID_export_memory, Smi::FromInt(static_cast<int>(export_memory)));
+  ret->set(kID_origin, Smi::FromInt(static_cast<int>(origin)));
+  return handle(WasmCompiledModule::cast(*ret));
+}
+
 compiler::CallDescriptor* ModuleEnv::GetCallDescriptor(Zone* zone,
                                                        uint32_t index) {
   DCHECK(IsValidFunction(index));
@@ -1761,11 +1778,9 @@ void SetInstanceMemory(Handle<JSObject> instance, JSArrayBuffer* buffer) {
   DisallowHeapAllocation no_gc;
   DCHECK(IsWasmObject(*instance));
   instance->SetInternalField(kWasmMemArrayBuffer, buffer);
-  Object* module = instance->GetInternalField(kWasmCompiledModule);
-  if (module->IsFixedArray()) {
-    WasmCompiledModule::cast(module)->set_mem_size(
-        buffer->byte_length()->Number());
-  }
+  WasmCompiledModule* module =
+      WasmCompiledModule::cast(instance->GetInternalField(kWasmCompiledModule));
+  module->set_ptr_to_heap(buffer);
 }
 
 namespace testing {

src/wasm/wasm-module.h

@@ -374,19 +374,6 @@ class WasmCompiledModule : public FixedArray {
 #define WCM_SMALL_NUMBER(TYPE, NAME)                               \
   TYPE NAME() const {                                              \
     return static_cast<TYPE>(Smi::cast(get(kID_##NAME))->value()); \
-  }                                                                \
-                                                                   \
-  void set_##NAME(TYPE value) {                                    \
-    set(kID_##NAME, Smi::FromInt(static_cast<int>(value)));        \
-  }
-
-#define WCM_LARGE_NUMBER(TYPE, NAME)                                          \
-  TYPE NAME() const {                                                         \
-    return static_cast<TYPE>(HeapNumber::cast(get(kID_##NAME))->value());     \
-  }                                                                           \
-                                                                              \
-  void set_##NAME(TYPE value) {                                               \
-    HeapNumber::cast(get(kID_##NAME))->set_value(static_cast<double>(value)); \
   }
 
 #define WCM_WEAK_LINK(TYPE, NAME)                        \
@@ -404,12 +391,11 @@ class WasmCompiledModule : public FixedArray {
   MACRO(OBJECT, FixedArray, indirect_function_tables) \
   MACRO(OBJECT, String, module_bytes)                 \
   MACRO(OBJECT, ByteArray, function_names)            \
-  MACRO(LARGE_NUMBER, uint32_t, min_required_memory)  \
+  MACRO(SMALL_NUMBER, uint32_t, min_memory_pages)     \
   MACRO(OBJECT, FixedArray, data_segments_info)       \
   MACRO(OBJECT, ByteArray, data_segments)             \
-  MACRO(LARGE_NUMBER, uint32_t, globals_size)         \
-  MACRO(LARGE_NUMBER, uint32_t, mem_size)             \
-  MACRO(OBJECT, JSArrayBuffer, mem_start)             \
+  MACRO(SMALL_NUMBER, uint32_t, globals_size)         \
+  MACRO(OBJECT, JSArrayBuffer, heap)                  \
   MACRO(SMALL_NUMBER, bool, export_memory)            \
   MACRO(SMALL_NUMBER, ModuleOrigin, origin)           \
   MACRO(WEAK_LINK, WasmCompiledModule, next_instance) \
@@ -425,34 +411,28 @@ class WasmCompiledModule : public FixedArray {
   };
 
  public:
-  static Handle<WasmCompiledModule> New(Isolate* isolate) {
-    Handle<FixedArray> ret =
-        isolate->factory()->NewFixedArray(PropertyIndices::Count, TENURED);
-    Handle<HeapNumber> number;
-#define WCM_INIT_OBJECT(IGNORE1, IGNORE2)
-#define WCM_INIT_WEAK_LINK(IGNORE1, IGNORE2)
-#define WCM_INIT_SMALL_NUMBER(IGNORE1, IGNORE2)
-#define WCM_INIT_LARGE_NUMBER(IGNORE, NAME)                          \
-  number = isolate->factory()->NewHeapNumber(0.0, MUTABLE, TENURED); \
-  ret->set(kID_##NAME, *number);
-
-#define INITIALIZER(KIND, TYPE, NAME) WCM_INIT_##KIND(TYPE, NAME)
-    WCM_PROPERTY_TABLE(INITIALIZER)
-#undef INITIALIZER
-    return handle(WasmCompiledModule::cast(*ret));
-  }
+  static Handle<WasmCompiledModule> New(Isolate* isolate,
+                                        uint32_t min_memory_pages,
+                                        uint32_t globals_size,
+                                        bool export_memory,
+                                        ModuleOrigin origin);
 
   static Handle<WasmCompiledModule> Clone(Isolate* isolate,
                                           Handle<WasmCompiledModule> module) {
     Handle<WasmCompiledModule> ret = Handle<WasmCompiledModule>::cast(
         isolate->factory()->CopyFixedArray(module));
-    Handle<HeapNumber> number =
-        isolate->factory()->NewHeapNumber(0.0, MUTABLE, TENURED);
-    ret->set(kID_mem_size, *number);
-    ret->set_mem_size(module->mem_size());
     return ret;
   }
 
+  uint32_t mem_size() const {
+    DCHECK(has_heap());
+    return heap()->byte_length()->Number();
+  }
+
+  uint32_t default_mem_size() const {
+    return min_memory_pages() * WasmModule::kPageSize;
+  }
+
 #define DECLARATION(KIND, TYPE, NAME) WCM_##KIND(TYPE, NAME)
   WCM_PROPERTY_TABLE(DECLARATION)
 #undef DECLARATION