[ast] Temporarily allow handle dereference for debug printing

src/ast/ast-numbering.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/ast/ast-numbering.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/objects-inl.h"
@@ skipping 631 matching lines @@
 
   VisitDeclarations(scope->declarations());
   VisitStatements(node->body());
 
   node->set_ast_properties(&properties_);
   node->set_dont_optimize_reason(dont_optimize_reason());
   node->set_yield_count(yield_count_);
 
   if (FLAG_trace_opt) {
     if (disable_crankshaft_reason_ != kNoReason) {
+      // TODO(leszeks): This is a quick'n'dirty fix to allow the debug name of
+      // the function to be accessed in the below print. This DCHECK will fail
+      // if we move ast numbering off the main thread, but that won't be before
+      // we remove FCG, in which case this entire check isn't necessary anyway.
+      AllowHandleDereference allow_deref;
+      DCHECK(!node->debug_name().is_null());
+
       PrintF("[enforcing Ignition and TurboFan for %s because: %s\n",
              node->debug_name()->ToCString().get(),
              GetBailoutReason(disable_crankshaft_reason_));
     }
   }
 
   return !HasStackOverflow();
 }
 
 bool AstNumbering::Renumber(
     uintptr_t stack_limit, Zone* zone, FunctionLiteral* function,
     Compiler::EagerInnerFunctionLiterals* eager_literals) {
   DisallowHeapAllocation no_allocation;
   DisallowHandleAllocation no_handles;
   DisallowHandleDereference no_deref;
 
   AstNumberingVisitor visitor(stack_limit, zone, eager_literals);
   return visitor.Renumber(function);
 }
 }  // namespace internal
 }  // namespace v8