[debugger] simplify compile for debugging.

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 <memory>
 
 #include "src/asmjs/asm-js.h"
@@ skipping 1102 matching lines @@
   function->ReplaceCode(*code);
   JSFunction::EnsureLiterals(function);
 
   // Check postconditions on success.
   DCHECK(!isolate->has_pending_exception());
   DCHECK(function->shared()->is_compiled());
   DCHECK(function->is_compiled());
   return true;
 }
 
-bool Compiler::CompileDebugCode(Handle<JSFunction> function) {
-  return CompileDebugCode(handle(function->shared()));
-}
-
 bool Compiler::CompileDebugCode(Handle<SharedFunctionInfo> shared) {
   Isolate* isolate = shared->GetIsolate();
+  // Code that cannot be compiled lazily are internal and not debuggable.
+  DCHECK(shared->allows_lazy_compilation());

[Michael Starzinger, 2016/11/14 09:19:11]

I don't fully understand why this became a pre-condition for this method. Can we
drop it? If this really is an important pre-condition we should be checking then
we should find a better place for it so that all paths benefit from it. Can we
drop it for now?

   DCHECK(AllowCompilation::IsAllowed(isolate));
 
   // Start a compilation.
   Zone zone(isolate->allocator(), ZONE_NAME);
   ParseInfo parse_info(&zone, shared);
   CompilationInfo info(&parse_info, Handle<JSFunction>::null());
   info.MarkAsDebug();
   if (GetUnoptimizedCode(&info).is_null()) {
     isolate->clear_pending_exception();
     return false;
@@ skipping 576 matching lines @@
     DCHECK(shared->is_compiled());
     function->set_literals(cached.literals);
   } else if (shared->is_compiled()) {
     // TODO(mvstanton): pass pretenure flag to EnsureLiterals.
     JSFunction::EnsureLiterals(function);
   }
 }
 
 }  // namespace internal
 }  // namespace v8