Retain current code in EnsureBytecodeArrayAvailable if not compiled

IsCompiledScope retains code to protect against code flushing. The
current API is easily misused by forgetting to initialize
IsCompiledScope with a SFI's current state.

Change-Id: Ie8ab60acc4fb85c4b8b76c52040976e2e34f9d5e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3674117Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80896}

src/codegen/pending-optimization-table.cc

@@ -32,7 +32,7 @@ void PendingOptimizationTable::PreparedForOptimization(
   }
   Handle<SharedFunctionInfo> shared_info(function->shared(), isolate);
 
-  IsCompiledScope is_compiled_scope = shared_info->is_compiled_scope(isolate);
+  IsCompiledScope is_compiled_scope;
   SharedFunctionInfo::EnsureBytecodeArrayAvailable(isolate, shared_info,
                                                    &is_compiled_scope);
 

src/objects/shared-function-info.cc

@@ -725,6 +725,8 @@ void SharedFunctionInfo::EnsureBytecodeArrayAvailable(
       FATAL("Failed to compile shared info that was already compiled before");
     }
     DCHECK(shared_info->GetBytecodeArray(isolate).HasSourcePositionTable());
+  } else {
+    *is_compiled_scope = shared_info->is_compiled_scope(isolate);
   }
 }
 

src/objects/shared-function-info.h

@@ -605,7 +605,7 @@ class SharedFunctionInfo
 
   static void EnsureBytecodeArrayAvailable(
       Isolate* isolate, Handle<SharedFunctionInfo> shared_info,
-      IsCompiledScope* is_compiled,
+      IsCompiledScope* is_compiled_scope,
       CreateSourcePositions flag = CreateSourcePositions::kNo);
 
   inline bool CanCollectSourcePosition(Isolate* isolate);