Make global eval faster by lazily computing its call position.

src/compiler.cc

 // Copyright 2012 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/compiler.h"
 
 #include <algorithm>
 
 #include "src/ast/ast-numbering.h"
 #include "src/ast/prettyprinter.h"
@@ skipping 1228 matching lines @@
     ParseRestriction restriction, int eval_scope_position, int eval_position,
     int line_offset, int column_offset, Handle<Object> script_name,
     ScriptOriginOptions options) {
   Isolate* isolate = source->GetIsolate();
   int source_length = source->length();
   isolate->counters()->total_eval_size()->Increment(source_length);
   isolate->counters()->total_compile_size()->Increment(source_length);
 
   CompilationCache* compilation_cache = isolate->compilation_cache();
   MaybeHandle<SharedFunctionInfo> maybe_shared_info =
       compilation_cache->LookupEval(source, outer_info, context, language_mode,

[Michael Starzinger, 2016/04/19 13:39:32]

This will perform a compilation cache lookup with a key containing the
SharedFunctionInfo for the top-level function always, independent from where the
global eval has been called. Is this safe?

                                     eval_scope_position);
   Handle<SharedFunctionInfo> shared_info;
 
   Handle<Script> script;
   if (!maybe_shared_info.ToHandle(&shared_info)) {
     script = isolate->factory()->NewScript(source);
     if (!script_name.is_null()) {
       script->set_name(*script_name);
       script->set_line_offset(line_offset);
       script->set_column_offset(column_offset);
     }
     script->set_origin_options(options);
     script->set_compilation_type(Script::COMPILATION_TYPE_EVAL);
-    script->set_eval_from_shared(*outer_info);
-    script->set_eval_from_position(eval_position);
+    Script::SetEvalOrigin(script, outer_info, eval_position);
 
     Zone zone(isolate->allocator());
     ParseInfo parse_info(&zone, script);
     CompilationInfo info(&parse_info, Handle<JSFunction>::null());
     parse_info.set_eval();
     if (context->IsNativeContext()) parse_info.set_global();
     parse_info.set_language_mode(language_mode);
     parse_info.set_parse_restriction(restriction);
     parse_info.set_context(context);
 
@@ skipping 411 matching lines @@
     MaybeHandle<Code> code;
     if (cached.code != nullptr) code = handle(cached.code);
     Handle<Context> native_context(function->context()->native_context());
     SharedFunctionInfo::AddToOptimizedCodeMap(shared, native_context, code,
                                               literals, BailoutId::None());
   }
 }
 
 }  // namespace internal
 }  // namespace v8