[test] Introduce a d8-only flag for fast calls

This CL introduces a d8-only flag --expose-fast-api which enables the
test FastCAPI object if the --turbo-fast-api-calls flag is enabled. It
also disables --stress-snapshot, which is incompatible with fast calls.

Bug: v8:12137
Change-Id: I01e8321726b78be660fd6554225999bfc94006c3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3117485Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76505}

src/d8/d8.cc

@@ -3007,7 +3007,7 @@ Local<ObjectTemplate> Shell::CreateD8Template(Isolate* isolate) {
     // Correctness fuzzing will attempt to compare results of tests with and
     // without turbo_fast_api_calls, so we don't expose the fast_c_api
     // constructor when --correctness_fuzzer_suppressions is on.
-    if (i::FLAG_turbo_fast_api_calls &&
+    if (options.expose_fast_api && i::FLAG_turbo_fast_api_calls &&
         !i::FLAG_correctness_fuzzer_suppressions) {
       test_template->Set(isolate, "FastCAPI",
                          Shell::CreateTestFastCApiTemplate(isolate));
@@ -4397,6 +4397,9 @@ bool Shell::SetOptions(int argc, char* argv[]) {
       options.wasm_trap_handler = false;
       argv[i] = nullptr;
 #endif  // V8_ENABLE_WEBASSEMBLY
+    } else if (strcmp(argv[i], "--expose-fast-api") == 0) {
+      options.expose_fast_api = true;
+      argv[i] = nullptr;
     }
   }
 
@@ -4424,6 +4427,11 @@ bool Shell::SetOptions(int argc, char* argv[]) {
   options.multi_mapped_mock_allocator = i::FLAG_multi_mapped_mock_allocator;
 #endif
 
+  if (i::FLAG_stress_snapshot && options.expose_fast_api &&
+      check_d8_flag_contradictions) {
+    FATAL("Flag --expose-fast-api is incompatible with --stress-snapshot.");
+  }
+
   // Set up isolated source groups.
   options.isolate_sources = new SourceGroup[options.num_isolates];
   SourceGroup* current = options.isolate_sources;

src/d8/d8.h

@@ -443,6 +443,7 @@ class ShellOptions {
 #if V8_ENABLE_WEBASSEMBLY
   DisallowReassignment<bool> wasm_trap_handler = {"wasm-trap-handler", true};
 #endif  // V8_ENABLE_WEBASSEMBLY
+  DisallowReassignment<bool> expose_fast_api = {"expose-fast-api", false};
 };
 
 class Shell : public i::AllStatic {

test/mjsunit/compiler/fast-api-calls.js

@@ -5,7 +5,7 @@
 // This file excercises basic fast API calls and enables fuzzing of this
 // functionality.
 
-// Flags: --turbo-fast-api-calls --allow-natives-syntax --opt
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --opt
 // --always-opt is disabled because we rely on particular feedback for
 // optimizing to the fastest path.
 // Flags: --no-always-opt

test/mjsunit/compiler/fast-api-helpers.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --turbo-fast-api-calls --allow-natives-syntax --opt
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --opt
 
 // Helper for sequence tests.
 function optimize_and_check(func, fast_count, slow_count, expected) {

test/mjsunit/compiler/fast-api-interface-types.js

@@ -4,7 +4,7 @@
 
 // This file interface types used with fast API calls.
 
-// Flags: --turbo-fast-api-calls --allow-natives-syntax --opt
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --opt
 // Flags: --no-always-opt
 // Flags: --deopt-every-n-times=0
 

test/mjsunit/compiler/fast-api-sequences-x64.js

@@ -4,7 +4,7 @@
 
 // This file adds x64 specific tests to the ones in fast-api-sequence.js.
 
-// Flags: --turbo-fast-api-calls --allow-natives-syntax --opt
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --opt
 // --always-opt is disabled because we rely on particular feedback for
 // optimizing to the fastest path.
 // Flags: --no-always-opt

test/mjsunit/compiler/fast-api-sequences.js

@@ -4,7 +4,7 @@
 
 // This file excercises sequences support for  fast API calls.
 
-// Flags: --turbo-fast-api-calls --allow-natives-syntax --opt
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --opt
 // --always-opt is disabled because we rely on particular feedback for
 // optimizing to the fastest path.
 // Flags: --no-always-opt

test/mjsunit/compiler/regress-crbug-1201011.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --turbo-fast-api-calls
+// Flags: --turbo-fast-api-calls --expose-fast-api
 
 const fast_c_api = new d8.test.FastCAPI();
 function foo(obj) {

test/mjsunit/compiler/regress-crbug-1201057.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --turbo-fast-api-calls
+// Flags: --turbo-fast-api-calls --expose-fast-api
 
 const fast_c_api = new d8.test.FastCAPI();
 const fast_obj = Object.create(fast_c_api);

test/mjsunit/compiler/regress-crbug-1201082.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --turbo-fast-api-calls
+// Flags: --turbo-fast-api-calls --expose-fast-api
 
 const fast_c_api = new d8.test.FastCAPI();
 function foo(obj) {

test/mjsunit/compiler/regress-crbug-1223107.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --turbo-fast-api-calls --allow-natives-syntax --opt
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --opt
 
 const fast_c_api = new d8.test.FastCAPI();
 assertThrows(() => {fast_c_api.add_all_sequence()});

test/mjsunit/compiler/regress-crbug-1241464.js

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --turbo-fast-api-calls
+// Flags: --turbo-fast-api-calls --expose-fast-api
 
 (function() {
   const fast_c_api = new d8.test.FastCAPI();

tools/testrunner/local/variants.py

@@ -64,7 +64,7 @@ INCOMPATIBLE_FLAGS_PER_VARIANT = {
   # serialized to the snapshot, so we don't have a
   # SerializeInternalFieldsCallback for it, so they are incompatible with
   # stress_snapshot.
-  "stress_snapshot": ["--turbo-fast-api-calls"],
+  "stress_snapshot": ["--expose-fast-api"],
   "stress": ["--always-opt", "--no-always-opt",
              "--max-inlined-bytecode-size=*",
              "--max-inlined-bytecode-size-cumulative=*", "--stress-inline",