Reland: [Parse] ParseInfo owns the parsing Zone.

src/asmjs/asm-wasm-builder.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 "src/v8.h"
 
 // Required to get M_E etc. in MSVC.
 #if defined(_WIN32)
 #define _USE_MATH_DEFINES
 #endif
@@ skipping 124 matching lines @@
     init_function_->Emit(kExprEnd);  // finish init function.
     return true;
   }
 
   void VisitVariableDeclaration(VariableDeclaration* decl) {}
 
   void VisitFunctionDeclaration(FunctionDeclaration* decl) {
     DCHECK_EQ(kModuleScope, scope_);
     DCHECK_NULL(current_function_builder_);
     FunctionLiteral* old_func = decl->fun();
-    Zone zone(isolate_->allocator(), ZONE_NAME);
     DeclarationScope* new_func_scope = nullptr;
+    std::unique_ptr<ParseInfo> info;

[marja, 2017/01/17 15:39:08]

Hmm, now the Zone cannot outlive ParseInfo? That sounds worrying... but I'll
read on!

[rmcilroy, 2017/01/19 12:48:29]

Acknowledged.

     if (decl->fun()->body() == nullptr) {
       // TODO(titzer/bradnelson): Reuse SharedFunctionInfos used here when
       // compiling the wasm module.
       Handle<SharedFunctionInfo> shared =
           Compiler::GetSharedFunctionInfo(decl->fun(), script_, info_);
       shared->set_is_toplevel(false);
-      ParseInfo info(&zone, script_);
-      info.set_shared_info(shared);
-      info.set_toplevel(false);
-      info.set_language_mode(decl->fun()->scope()->language_mode());
-      info.set_allow_lazy_parsing(false);
-      info.set_function_literal_id(shared->function_literal_id());
-      info.set_ast_value_factory(ast_value_factory_);
-      info.set_ast_value_factory_owned(false);
+      info.reset(new ParseInfo(script_));
+      info->set_shared_info(shared);
+      info->set_toplevel(false);
+      info->set_language_mode(decl->fun()->scope()->language_mode());
+      info->set_allow_lazy_parsing(false);
+      info->set_function_literal_id(shared->function_literal_id());
+      info->set_ast_value_factory(ast_value_factory_);
+      info->set_ast_value_factory_owned(false);
       // Create fresh function scope to use to parse the function in.
-      new_func_scope = new (info.zone()) DeclarationScope(
-          info.zone(), decl->fun()->scope()->outer_scope(), FUNCTION_SCOPE);
-      info.set_asm_function_scope(new_func_scope);
-      if (!Compiler::ParseAndAnalyze(&info)) {
+      new_func_scope = new (info->zone()) DeclarationScope(
+          info->zone(), decl->fun()->scope()->outer_scope(), FUNCTION_SCOPE);
+      info->set_asm_function_scope(new_func_scope);
+      if (!Compiler::ParseAndAnalyze(info.get())) {
         typer_failed_ = true;
         return;
       }
-      FunctionLiteral* func = info.literal();
+      FunctionLiteral* func = info->literal();
       DCHECK_NOT_NULL(func);
       decl->set_fun(func);
     }
     if (!typer_->ValidateInnerFunction(decl)) {
       typer_failed_ = true;
       decl->set_fun(old_func);
       if (new_func_scope != nullptr) {
         DCHECK_EQ(new_func_scope, decl->scope()->inner_scope());
         if (!decl->scope()->RemoveInnerScope(new_func_scope)) {
           UNREACHABLE();
@@ skipping 1821 matching lines @@
   impl.builder_->WriteAsmJsOffsetTable(*asm_offsets_buffer);
   return {module_buffer, asm_offsets_buffer, success};
 }
 
 const char* AsmWasmBuilder::foreign_init_name = "__foreign_init__";
 const char* AsmWasmBuilder::single_function_name = "__single_function__";
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8