From aee1effa487849cc3c48c28c60a866211b05ebae Mon Sep 17 00:00:00 2001
From: Jon Coppeard <jcoppeard@mozilla.com>
Date: Tue, 14 Feb 2023 10:32:47 +0000
Subject: [PATCH] Part 1: Disallow GC while iterating global's debugger vector

Conflict:NA
Reference:https://hg.mozilla.org/integration/autoland/rev/760275af660b20d35ace80f4d245c4ad9c4a3869
---
 js/src/debugger/Debugger.cpp | 37 +++++++++++++++++++++++-------------
 js/src/debugger/Debugger.h   | 10 ++++++----
 js/src/gc/GC.h               |  2 +-
 3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/js/src/debugger/Debugger.cpp b/js/src/debugger/Debugger.cpp
index be22c18354..56a172c457 100644
--- a/js/src/debugger/Debugger.cpp
+++ b/js/src/debugger/Debugger.cpp
@@ -1240,8 +1240,9 @@ bool DebugAPI::slowPathOnNewGenerator(JSContext* cx, AbstractFramePtr frame,
       MakeScopeExit([&] { Debugger::terminateDebuggerFrames(cx, frame); });
 
   bool ok = true;
+  gc::AutoSuppressGC nogc(cx);
   Debugger::forEachOnStackDebuggerFrame(
-      frame, [&](Debugger* dbg, DebuggerFrame* frameObjPtr) {
+      frame, nogc, [&](Debugger* dbg, DebuggerFrame* frameObjPtr) {
         if (!ok) {
           return;
         }
@@ -3265,7 +3266,10 @@ bool Debugger::updateExecutionObservabilityOfScripts(
 
 template <typename FrameFn>
 /* static */
-void Debugger::forEachOnStackDebuggerFrame(AbstractFramePtr frame, FrameFn fn) {
+void Debugger::forEachOnStackDebuggerFrame(AbstractFramePtr frame,
+                                           const JS::AutoRequireNoGC& nogc,
+                                           FrameFn fn) {
+  // GC is disallowed because it may mutate the vector we are iterating.
   for (Realm::DebuggerVectorEntry& entry : frame.global()->getDebuggers()) {
     Debugger* dbg = entry.dbg;
     if (FrameMap::Ptr frameEntry = dbg->frames.lookup(frame)) {
@@ -3276,9 +3280,10 @@ void Debugger::forEachOnStackDebuggerFrame(AbstractFramePtr frame, FrameFn fn) {
 
 template <typename FrameFn>
 /* static */
-void Debugger::forEachOnStackOrSuspendedDebuggerFrame(JSContext* cx,
-                                                      AbstractFramePtr frame,
-                                                      FrameFn fn) {
+void Debugger::forEachOnStackOrSuspendedDebuggerFrame(
+    JSContext* cx, AbstractFramePtr frame, const JS::AutoRequireNoGC& nogc,
+    FrameFn fn) {
+  // GC is disallowed because it may mutate the vector we are iterating.
   Rooted<AbstractGeneratorObject*> genObj(
       cx, frame.isGeneratorFrame() ? GetGeneratorObjectForFrame(cx, frame)
                                    : nullptr);
@@ -3304,11 +3309,13 @@ void Debugger::forEachOnStackOrSuspendedDebuggerFrame(JSContext* cx,
 bool Debugger::getDebuggerFrames(AbstractFramePtr frame,
                                  MutableHandle<DebuggerFrameVector> frames) {
   bool hadOOM = false;
-  forEachOnStackDebuggerFrame(frame, [&](Debugger*, DebuggerFrame* frameobj) {
-    if (!hadOOM && !frames.append(frameobj)) {
-      hadOOM = true;
-    }
-  });
+  JS::AutoAssertNoGC nogc;
+  forEachOnStackDebuggerFrame(frame, nogc,
+                              [&](Debugger*, DebuggerFrame* frameobj) {
+                                if (!hadOOM && !frames.append(frameobj)) {
+                                  hadOOM = true;
+                                }
+                              });
   return !hadOOM;
 }
 
@@ -6466,8 +6473,10 @@ bool Debugger::replaceFrameGuts(JSContext* cx, AbstractFramePtr from,
 /* static */
 bool DebugAPI::inFrameMaps(AbstractFramePtr frame) {
   bool foundAny = false;
+  JS::AutoAssertNoGC nogc;
   Debugger::forEachOnStackDebuggerFrame(
-      frame, [&](Debugger*, DebuggerFrame* frameobj) { foundAny = true; });
+      frame, nogc,
+      [&](Debugger*, DebuggerFrame* frameobj) { foundAny = true; });
   return foundAny;
 }
 
@@ -6475,8 +6484,9 @@ bool DebugAPI::inFrameMaps(AbstractFramePtr frame) {
 void Debugger::suspendGeneratorDebuggerFrames(JSContext* cx,
                                               AbstractFramePtr frame) {
   JSFreeOp* fop = cx->runtime()->defaultFreeOp();
+  JS::AutoAssertNoGC nogc;
   forEachOnStackDebuggerFrame(
-      frame, [&](Debugger* dbg, DebuggerFrame* dbgFrame) {
+      frame, nogc, [&](Debugger* dbg, DebuggerFrame* dbgFrame) {
         dbg->frames.remove(frame);
 
 #if DEBUG
@@ -6495,8 +6505,9 @@ void Debugger::suspendGeneratorDebuggerFrames(JSContext* cx,
 void Debugger::terminateDebuggerFrames(JSContext* cx, AbstractFramePtr frame) {
   JSFreeOp* fop = cx->runtime()->defaultFreeOp();
 
+  JS::AutoAssertNoGC nogc;
   forEachOnStackOrSuspendedDebuggerFrame(
-      cx, frame, [&](Debugger* dbg, DebuggerFrame* dbgFrame) {
+      cx, frame, nogc, [&](Debugger* dbg, DebuggerFrame* dbgFrame) {
         Debugger::terminateDebuggerFrame(fop, dbg, dbgFrame, frame);
       });
 
diff --git a/js/src/debugger/Debugger.h b/js/src/debugger/Debugger.h
index bc89e4bfb1..d9da8bbe36 100644
--- a/js/src/debugger/Debugger.h
+++ b/js/src/debugger/Debugger.h
@@ -930,11 +930,13 @@ class Debugger : private mozilla::LinkedListElement<Debugger> {
       IsObserving observing);
 
   template <typename FrameFn /* void (Debugger*, DebuggerFrame*) */>
-  static void forEachOnStackDebuggerFrame(AbstractFramePtr frame, FrameFn fn);
+  static void forEachOnStackDebuggerFrame(AbstractFramePtr frame,
+                                          const JS::AutoRequireNoGC& nogc,
+                                          FrameFn fn);
   template <typename FrameFn /* void (Debugger*, DebuggerFrame*) */>
-  static void forEachOnStackOrSuspendedDebuggerFrame(JSContext* cx,
-                                                     AbstractFramePtr frame,
-                                                     FrameFn fn);
+  static void forEachOnStackOrSuspendedDebuggerFrame(
+      JSContext* cx, AbstractFramePtr frame, const JS::AutoRequireNoGC& nogc,
+      FrameFn fn);
 
   /*
    * Return a vector containing all Debugger.Frame instances referring to
diff --git a/js/src/gc/GC.h b/js/src/gc/GC.h
index 9cee0190b6..c6fe40c263 100644
--- a/js/src/gc/GC.h
+++ b/js/src/gc/GC.h
@@ -179,7 +179,7 @@ static inline void MaybeVerifyBarriers(JSContext* cx, bool always = false) {}
  * This works by updating the |JSContext::suppressGC| counter which is checked
  * at the start of GC.
  */
-class MOZ_RAII JS_HAZ_GC_SUPPRESSED AutoSuppressGC {
+class MOZ_RAII JS_HAZ_GC_SUPPRESSED AutoSuppressGC : public JS::AutoRequireNoGC {
   int32_t& suppressGC_;
 
  public:
-- 
2.33.0