Bug 1817933: Don't elide shapeguard for debugger targets r=jandem

Differential Revision: https://phabricator.services.mozilla.com/D171520

js/src/jit-test/tests/debug/bug1817933.js

@@ -0,0 +1,16 @@
+var g = newGlobal({"newCompartment": true});
+const dbg = new g.Debugger(this);
+
+with ({x: 3}) {
+  function foo(n) {
+    () => {n}
+
+    if (n < 20) {
+      foo(n+1);
+    } else {
+      dbg.getNewestFrame().eval("var x = 23;");
+    }
+    +x
+  }
+  foo(0);
+}

js/src/jit/CacheIR.cpp

@@ -3160,7 +3160,7 @@ AttachDecision GetNameIRGenerator::tryAttachGlobalNameGetter(ObjOperandId objId,
   return AttachDecision::Attach;
 }
 
-static bool NeedEnvironmentShapeGuard(JSObject* envObj) {
+static bool NeedEnvironmentShapeGuard(JSContext* cx, JSObject* envObj) {
   if (!envObj->is<CallObject>()) {
     return true;
   }
@@ -3171,7 +3171,8 @@ static bool NeedEnvironmentShapeGuard(JSObject* envObj) {
   // and we pessimistically create the guard.
   CallObject* callObj = &envObj->as<CallObject>();
   JSFunction* fun = &callObj->callee();
-  if (!fun->hasBaseScript() || fun->baseScript()->funHasExtensibleScope()) {
+  if (!fun->hasBaseScript() || fun->baseScript()->funHasExtensibleScope() ||
+      DebugEnvironments::hasDebugEnvironment(cx, *callObj)) {
     return true;
   }
 
@@ -3236,7 +3237,7 @@ AttachDecision GetNameIRGenerator::tryAttachEnvironmentName(ObjOperandId objId,
   ObjOperandId lastObjId = objId;
   env = env_;
   while (env) {
-    if (NeedEnvironmentShapeGuard(env)) {
+    if (NeedEnvironmentShapeGuard(cx_, env)) {
       writer.guardShape(lastObjId, env->shape());
     }
 
@@ -3381,7 +3382,7 @@ AttachDecision BindNameIRGenerator::tryAttachEnvironmentName(ObjOperandId objId,
   ObjOperandId lastObjId = objId;
   env = env_;
   while (env) {
-    if (NeedEnvironmentShapeGuard(env) && !env->is<GlobalObject>()) {
+    if (NeedEnvironmentShapeGuard(cx_, env) && !env->is<GlobalObject>()) {
       writer.guardShape(lastObjId, env->shape());
     }