[wasm] Prerequisites for WebAssembly Table.Grow

src/wasm/wasm-module.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <memory>
 
 #include "src/assembler-inl.h"
 #include "src/base/adapters.h"
 #include "src/base/atomic-utils.h"
 #include "src/code-stubs.h"
@@ skipping 831 matching lines @@
   WasmInstance temp_instance(this);
   temp_instance.context = isolate->native_context();
   temp_instance.mem_size = WasmModule::kPageSize * min_mem_pages;
   temp_instance.mem_start = nullptr;
   temp_instance.globals_start = nullptr;
 
   // Initialize the indirect tables with placeholders.
   int function_table_count = static_cast<int>(function_tables.size());
   Handle<FixedArray> function_tables =
       factory->NewFixedArray(function_table_count, TENURED);
+  Handle<FixedArray> signature_tables =
+      factory->NewFixedArray(function_table_count, TENURED);
   for (int i = 0; i < function_table_count; ++i) {
-    temp_instance.function_tables[i] = factory->NewFixedArray(0, TENURED);
+    temp_instance.function_tables[i] = factory->NewFixedArray(1, TENURED);
+    temp_instance.signature_tables[i] = factory->NewFixedArray(1, TENURED);
     function_tables->set(i, *temp_instance.function_tables[i]);
+    signature_tables->set(i, *temp_instance.signature_tables[i]);
   }
 
   HistogramTimerScope wasm_compile_module_time_scope(
       isolate->counters()->wasm_compile_module_time());
 
   ModuleBytesEnv module_env(this, &temp_instance, wire_bytes);
 
   // The {code_table} array contains import wrappers and functions (which
   // are both included in {functions.size()}, and export wrappers.
   int code_table_size =
@@ skipping 82 matching lines @@
   // Create the compiled module object, and populate with compiled functions
   // 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, shared);
   ret->set_code_table(code_table);
   ret->set_min_mem_pages(min_mem_pages);
   ret->set_max_mem_pages(max_mem_pages);
   if (function_table_count > 0) {
     ret->set_function_tables(function_tables);
+    ret->set_signature_tables(signature_tables);
     ret->set_empty_function_tables(function_tables);
   }
 
   // If we created a wasm script, finish it now and make it public to the
   // debugger.
   if (asm_js_script.is_null()) {
     script->set_wasm_compiled_module(*ret);
     isolate->debug()->OnAfterCompile(script);
   }
 
@@ skipping 68 matching lines @@
     // Signature mismatch. Compile a new wrapper for the new signature.
     return compiler::CompileWasmToJSWrapper(isolate, target, sig, index,
                                             module_name, import_name, origin);
   }
 }
 
 static void UpdateDispatchTablesInternal(Isolate* isolate,
                                          Handle<FixedArray> dispatch_tables,
                                          int index, WasmFunction* function,
                                          Handle<Code> code) {
-  DCHECK_EQ(0, dispatch_tables->length() % 3);
-  for (int i = 0; i < dispatch_tables->length(); i += 3) {
+  DCHECK_EQ(0, dispatch_tables->length() % 4);
+  for (int i = 0; i < dispatch_tables->length(); i += 4) {
     int table_index = Smi::cast(dispatch_tables->get(i + 1))->value();
-    Handle<FixedArray> dispatch_table(
+    Handle<FixedArray> function_table(
         FixedArray::cast(dispatch_tables->get(i + 2)), isolate);
+    Handle<FixedArray> signature_table(
+        FixedArray::cast(dispatch_tables->get(i + 3)), isolate);
     if (function) {
       // TODO(titzer): the signature might need to be copied to avoid
       // a dangling pointer in the signature map.
       Handle<WasmInstanceObject> instance(
           WasmInstanceObject::cast(dispatch_tables->get(i)), isolate);
       int sig_index = static_cast<int>(
           instance->module()->function_tables[table_index].map.FindOrInsert(
               function->sig));
-      dispatch_table->set(index, Smi::FromInt(sig_index));
-      dispatch_table->set(index + (dispatch_table->length() / 2), *code);
+      signature_table->set(index, Smi::FromInt(sig_index));
+      function_table->set(index, *code);
     } else {
       Code* code = nullptr;
-      dispatch_table->set(index, Smi::FromInt(-1));
-      dispatch_table->set(index + (dispatch_table->length() / 2), code);
+      signature_table->set(index, Smi::FromInt(-1));
+      function_table->set(index, code);
     }
   }
 }
 
 void wasm::UpdateDispatchTables(Isolate* isolate,
                                 Handle<FixedArray> dispatch_tables, int index,
                                 Handle<JSFunction> function) {
   if (function.is_null()) {
     UpdateDispatchTablesInternal(isolate, dispatch_tables, index, nullptr,
                                  Handle<Code>::null());
@@ skipping 126 matching lines @@
       instance->set_globals_buffer(*global_buffer);
     }
 
     //--------------------------------------------------------------------------
     // Prepare for initialization of function tables.
     //--------------------------------------------------------------------------
     int function_table_count =
         static_cast<int>(module_->function_tables.size());
     table_instances_.reserve(module_->function_tables.size());
     for (int index = 0; index < function_table_count; ++index) {
-      table_instances_.push_back({Handle<WasmTableObject>::null(),
-                                  Handle<FixedArray>::null(),
-                                  Handle<FixedArray>::null()});
+      table_instances_.push_back(
+          {Handle<WasmTableObject>::null(), Handle<FixedArray>::null(),
+           Handle<FixedArray>::null(), Handle<FixedArray>::null()});
     }
 
     //--------------------------------------------------------------------------
     // Process the imports for the module.
     //--------------------------------------------------------------------------
     int num_imported_functions = ProcessImports(code_table, instance);
     if (num_imported_functions < 0) return nothing;
 
     //--------------------------------------------------------------------------
     // Process the initialization for the module's globals.
@@ skipping 185 matching lines @@
     TRACE("Finishing instance %d\n", compiled_module_->instance_id());
     TRACE_CHAIN(WasmCompiledModule::cast(module_object_->GetInternalField(0)));
     return instance;
   }
 
  private:
   // Represents the initialized state of a table.
   struct TableInstance {
     Handle<WasmTableObject> table_object;    // WebAssembly.Table instance
     Handle<FixedArray> js_wrappers;          // JSFunctions exported
-    Handle<FixedArray> dispatch_table;       // internal (code, sig) pairs
+    Handle<FixedArray> function_table;       // internal code array
+    Handle<FixedArray> signature_table;      // internal sig array
   };
 
   Isolate* isolate_;
   WasmModule* module_;
   ErrorThrower* thrower_;
   Handle<JSObject> module_object_;
   Handle<JSReceiver> ffi_;
   Handle<JSArrayBuffer> memory_;
   Handle<JSArrayBuffer> globals_;
   Handle<WasmCompiledModule> compiled_module_;
@@ skipping 184 matching lines @@
 
           // TODO(titzer): import table size must match exactly for now.
           int table_size = table_instance.js_wrappers->length();
           if (table_size != static_cast<int>(table.min_size)) {
             thrower_->LinkError(
                 "table import %d is wrong size (%d), expected %u", index,
                 table_size, table.min_size);
             return -1;
           }
 
-          // Allocate a new dispatch table.
-          table_instance.dispatch_table =
-              isolate_->factory()->NewFixedArray(table_size * 2);
-          for (int i = 0; i < table_size * 2; ++i) {
-            table_instance.dispatch_table->set(i,
-                                               Smi::FromInt(kInvalidSigIndex));
+          // Allocate a new dispatch table and signature table.
+          table_instance.function_table =
+              isolate_->factory()->NewFixedArray(table_size);
+          table_instance.signature_table =
+              isolate_->factory()->NewFixedArray(table_size);
+          for (int i = 0; i < table_size; ++i) {
+            table_instance.signature_table->set(i,
+                                                Smi::FromInt(kInvalidSigIndex));
           }
           // Initialize the dispatch table with the (foreign) JS functions
           // that are already in the table.
           for (int i = 0; i < table_size; ++i) {
             Handle<Object> val(table_instance.js_wrappers->get(i), isolate_);
             if (!val->IsJSFunction()) continue;
             WasmFunction* function =
                 GetWasmFunctionForImportWrapper(isolate_, val);
             if (function == nullptr) {
               thrower_->LinkError("table import %d[%d] is not a WASM function",
                                   index, i);
               return -1;
             }
             int sig_index = table.map.FindOrInsert(function->sig);
-            table_instance.dispatch_table->set(i, Smi::FromInt(sig_index));
-            table_instance.dispatch_table->set(i + table_size,
-                                               *UnwrapImportWrapper(val));
+            table_instance.signature_table->set(i, Smi::FromInt(sig_index));
+            table_instance.function_table->set(i, *UnwrapImportWrapper(val));
           }
 
           num_imported_tables++;
           break;
         }
         case kExternalMemory: {
           if (!WasmJs::IsWasmMemoryObject(isolate_, value)) {
             ReportLinkError("memory import must be a WebAssembly.Memory object",
                             index, module_name, import_name);
             return -1;
@@ skipping 244 matching lines @@
           exports_object, FROZEN, Object::DONT_THROW);
       DCHECK(success.FromMaybe(false));
       USE(success);
     }
   }
 
   void InitializeTables(Handle<FixedArray> code_table,
                         Handle<WasmInstanceObject> instance) {
     Handle<FixedArray> old_function_tables =
         compiled_module_->function_tables();
+    Handle<FixedArray> old_signature_tables =
+        compiled_module_->signature_tables();
     int function_table_count =
         static_cast<int>(module_->function_tables.size());
     Handle<FixedArray> new_function_tables =
         isolate_->factory()->NewFixedArray(function_table_count);
+    Handle<FixedArray> new_signature_tables =
+        isolate_->factory()->NewFixedArray(function_table_count);
     for (int index = 0; index < function_table_count; ++index) {
       WasmIndirectFunctionTable& table = module_->function_tables[index];
       TableInstance& table_instance = table_instances_[index];
       int table_size = static_cast<int>(table.min_size);
 
-      if (table_instance.dispatch_table.is_null()) {
+      if (table_instance.function_table.is_null()) {
         // Create a new dispatch table if necessary.
-        table_instance.dispatch_table =
-            isolate_->factory()->NewFixedArray(table_size * 2);
+        table_instance.function_table =
+            isolate_->factory()->NewFixedArray(table_size);
+        table_instance.signature_table =
+            isolate_->factory()->NewFixedArray(table_size);
         for (int i = 0; i < table_size; ++i) {
           // Fill the table with invalid signature indexes so that
           // uninitialized entries will always fail the signature check.
-          table_instance.dispatch_table->set(i, Smi::FromInt(kInvalidSigIndex));
+          table_instance.signature_table->set(i,
+                                              Smi::FromInt(kInvalidSigIndex));
         }
       }
 
       new_function_tables->set(static_cast<int>(index),
-                               *table_instance.dispatch_table);
+                               *table_instance.function_table);
+      new_signature_tables->set(static_cast<int>(index),
+                                *table_instance.signature_table);
 
       Handle<FixedArray> all_dispatch_tables;
       if (!table_instance.table_object.is_null()) {
         // Get the existing dispatch table(s) with the WebAssembly.Table object.
         all_dispatch_tables = WasmTableObject::AddDispatchTable(
             isolate_, table_instance.table_object,
             Handle<WasmInstanceObject>::null(), index,
-            Handle<FixedArray>::null());
+            Handle<FixedArray>::null(), Handle<FixedArray>::null());
       }
 
       // TODO(titzer): this does redundant work if there are multiple tables,
       // since initializations are not sorted by table index.
       for (auto table_init : module_->table_inits) {
         uint32_t base = EvalUint32InitExpr(table_init.offset);
         if (base > static_cast<uint32_t>(table_size) ||
             (base + table_init.entries.size() >
              static_cast<uint32_t>(table_size))) {
           thrower_->LinkError("table initializer is out of bounds");
           continue;
         }
         for (int i = 0; i < static_cast<int>(table_init.entries.size()); ++i) {
           uint32_t func_index = table_init.entries[i];
           WasmFunction* function = &module_->functions[func_index];
           int table_index = static_cast<int>(i + base);
           int32_t sig_index = table.map.Find(function->sig);
           DCHECK_GE(sig_index, 0);
-          table_instance.dispatch_table->set(table_index,
-                                             Smi::FromInt(sig_index));
-          table_instance.dispatch_table->set(table_index + table_size,
+          table_instance.signature_table->set(table_index,
+                                              Smi::FromInt(sig_index));
+          table_instance.function_table->set(table_index,
                                              code_table->get(func_index));
 
           if (!all_dispatch_tables.is_null()) {
             Handle<Code> wasm_code(Code::cast(code_table->get(func_index)),
                                    isolate_);
             if (js_wrappers_[func_index].is_null()) {
               // No JSFunction entry yet exists for this function. Create one.
               // TODO(titzer): We compile JS->WASM wrappers for functions are
               // not exported but are in an exported table. This should be done
               // at module compile time and cached instead.
@@ skipping 30 matching lines @@
         }
       }
 
       // TODO(titzer): we add the new dispatch table at the end to avoid
       // redundant work and also because the new instance is not yet fully
       // initialized.
       if (!table_instance.table_object.is_null()) {
         // Add the new dispatch table to the WebAssembly.Table object.
         all_dispatch_tables = WasmTableObject::AddDispatchTable(
             isolate_, table_instance.table_object, instance, index,
-            table_instance.dispatch_table);
+            table_instance.function_table, table_instance.signature_table);
       }
     }
     // Patch all code that has references to the old indirect tables.
     for (int i = 0; i < code_table->length(); ++i) {
       if (!code_table->get(i)->IsCode()) continue;
       Handle<Code> code(Code::cast(code_table->get(i)), isolate_);
       for (int j = 0; j < function_table_count; ++j) {
         ReplaceReferenceInCode(
             code, Handle<Object>(old_function_tables->get(j), isolate_),
             Handle<Object>(new_function_tables->get(j), isolate_));
+        ReplaceReferenceInCode(
+            code, Handle<Object>(old_signature_tables->get(j), isolate_),
+            Handle<Object>(new_signature_tables->get(j), isolate_));
       }
     }
     compiled_module_->set_function_tables(new_function_tables);
+    compiled_module_->set_signature_tables(new_signature_tables);
   }
 };
 
 // Instantiates a WASM module, creating a WebAssembly.Instance from a
 // WebAssembly.Module.
 MaybeHandle<WasmInstanceObject> WasmModule::Instantiate(
     Isolate* isolate, ErrorThrower* thrower, Handle<JSObject> wasm_module,
     Handle<JSReceiver> ffi, Handle<JSArrayBuffer> memory) {
   WasmInstanceBuilder builder(isolate, thrower, wasm_module, ffi, memory);
   return builder.Build();
@@ skipping 263 matching lines @@
   CHECK(!compiled_module->has_weak_owning_instance());
 }
 
 void testing::ValidateOrphanedInstance(Isolate* isolate,
                                        Handle<WasmInstanceObject> instance) {
   DisallowHeapAllocation no_gc;
   WasmCompiledModule* compiled_module = instance->compiled_module();
   CHECK(compiled_module->has_weak_wasm_module());
   CHECK(compiled_module->ptr_to_weak_wasm_module()->cleared());
 }