[debug, execution, heap] Iterate debug roots for archived threads

Dominik Inführ · Commit Bot · commit f8794dcafe4c · 2020-11-17T08:52:01.000Z
When a thread gets archived, we still need to scan and update debug roots on GCs for it. Otherwise we restore stale references when the thread becomes active again. Bug: v8:11145 Change-Id: I88f4c1534e826aed222e7fb67bd82bb0a4758fab Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2537691 Reviewed-by: Ulan Degenbaev <ulan@chromium.org> Reviewed-by: Simon Zünd <szuend@chromium.org> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org> Cr-Commit-Position: refs/heads/master@{#71221}
diff --git a/src/debug/debug.cc b/src/debug/debug.cc
@@ -393,14 +393,23 @@ char* Debug::RestoreDebug(char* storage) {
 
 int Debug::ArchiveSpacePerThread() { return sizeof(ThreadLocal); }
 
-void Debug::Iterate(RootVisitor* v) {
+void Debug::Iterate(RootVisitor* v) { Iterate(v, &thread_local_); }
+
+char* Debug::Iterate(RootVisitor* v, char* thread_storage) {
+  ThreadLocal* thread_local_data =
+      reinterpret_cast<ThreadLocal*>(thread_storage);
+  Iterate(v, thread_local_data);
+  return thread_storage + ArchiveSpacePerThread();
+}
+
+void Debug::Iterate(RootVisitor* v, ThreadLocal* thread_local_data) {
   v->VisitRootPointer(Root::kDebug, nullptr,
-                      FullObjectSlot(&thread_local_.return_value_));
+                      FullObjectSlot(&thread_local_data->return_value_));
   v->VisitRootPointer(Root::kDebug, nullptr,
-                      FullObjectSlot(&thread_local_.suspended_generator_));
+                      FullObjectSlot(&thread_local_data->suspended_generator_));
   v->VisitRootPointer(
       Root::kDebug, nullptr,
-      FullObjectSlot(&thread_local_.ignore_step_into_function_));
+      FullObjectSlot(&thread_local_data->ignore_step_into_function_));
 }
 
 DebugInfoListNode::DebugInfoListNode(Isolate* isolate, DebugInfo debug_info)
diff --git a/src/debug/debug.h b/src/debug/debug.h
@@ -392,6 +392,8 @@ class V8_EXPORT_PRIVATE Debug {
 
   void RemoveBreakInfoAndMaybeFree(Handle<DebugInfo> debug_info);
 
+  static char* Iterate(RootVisitor* v, char* thread_storage);
+
  private:
   explicit Debug(Isolate* isolate);
   ~Debug();
@@ -546,6 +548,8 @@ class V8_EXPORT_PRIVATE Debug {
     bool break_on_next_function_call_;
   };
 
+  static void Iterate(RootVisitor* v, ThreadLocal* thread_local_data);
+
   // Storage location for registers when handling debug break calls
   ThreadLocal thread_local_;
 
diff --git a/src/execution/stack-guard.h b/src/execution/stack-guard.h
@@ -16,6 +16,7 @@ class ExecutionAccess;
 class InterruptsScope;
 class Isolate;
 class Object;
+class RootVisitor;
 
 // StackGuard contains the handling of the limits that are used to limit the
 // number of nested invocations of JavaScript and the stack size used in each
@@ -88,6 +89,10 @@ class V8_EXPORT_PRIVATE StackGuard final {
 
   static constexpr int kSizeInBytes = 7 * kSystemPointerSize;
 
+  static char* Iterate(RootVisitor* v, char* thread_storage) {
+    return thread_storage + ArchiveSpacePerThread();
+  }
+
  private:
   bool CheckInterrupt(InterruptFlag flag);
   void RequestInterrupt(InterruptFlag flag);
diff --git a/src/execution/v8threads.cc b/src/execution/v8threads.cc
@@ -8,6 +8,7 @@
 #include "src/debug/debug.h"
 #include "src/execution/execution.h"
 #include "src/execution/isolate-inl.h"
+#include "src/execution/stack-guard.h"
 #include "src/init/bootstrapper.h"
 #include "src/objects/visitors.h"
 #include "src/regexp/regexp-stack.h"
@@ -298,6 +299,8 @@ void ThreadManager::Iterate(RootVisitor* v) {
     data = HandleScopeImplementer::Iterate(v, data);
     data = isolate_->Iterate(v, data);
     data = Relocatable::Iterate(v, data);
+    data = StackGuard::Iterate(v, data);
+    data = Debug::Iterate(v, data);
   }
 }
 
