[test][compiler] Add flag --stress-concurrent-inlining-attach-code

It works like --stress-concurrent-inlining but instead of throwing
away the produced code it attaches it to the function as usual. This
mode will be used for fuzzing.

Bug: v8:7790
Change-Id: I010cbb7ab7ec29fccfa561eaff72e66c7444239f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3140602Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76669}

src/codegen/compiler.cc

@@ -1179,9 +1179,13 @@ void SpawnDuplicateConcurrentJobForStressTesting(Isolate* isolate,
          isolate->concurrent_recompilation_enabled() &&
          mode == ConcurrencyMode::kNotConcurrent &&
          isolate->node_observer() == nullptr);
+  GetOptimizedCodeResultHandling result_handling =
+      FLAG_stress_concurrent_inlining_attach_code
+          ? GetOptimizedCodeResultHandling::kDefault
+          : GetOptimizedCodeResultHandling::kDiscardForTesting;
   USE(GetOptimizedCode(isolate, function, ConcurrencyMode::kConcurrent,
                        code_kind, BytecodeOffset::None(), nullptr,
-                       GetOptimizedCodeResultHandling::kDiscardForTesting));
+                       result_handling));
 }
 
 bool FailAndClearPendingException(Isolate* isolate) {

src/flags/flag-definitions.h

@@ -713,12 +713,17 @@ DEFINE_INT(concurrent_recompilation_delay, 0,
            "artificial compilation delay in ms")
 DEFINE_BOOL(concurrent_inlining, true,
             "run optimizing compiler's inlining phase on a separate thread")
-DEFINE_BOOL(stress_concurrent_inlining, false,
-            "makes concurrent inlining more likely to trigger in tests")
+DEFINE_BOOL(
+    stress_concurrent_inlining, false,
+    "create additional concurrent optimization jobs but throw away result")
 DEFINE_IMPLICATION(stress_concurrent_inlining, concurrent_inlining)
 DEFINE_NEG_IMPLICATION(stress_concurrent_inlining, lazy_feedback_allocation)
 DEFINE_WEAK_VALUE_IMPLICATION(stress_concurrent_inlining, interrupt_budget,
                               15 * KB)
+DEFINE_BOOL(stress_concurrent_inlining_attach_code, false,
+            "create additional concurrent optimization jobs")
+DEFINE_IMPLICATION(stress_concurrent_inlining_attach_code,
+                   stress_concurrent_inlining)
 DEFINE_INT(max_serializer_nesting, 25,
            "maximum levels for nesting child serializers")
 DEFINE_BOOL(trace_heap_broker_verbose, false,