[nojit] Add a few flag implications based on --jitless

--jitless -> --no-opt
          -> --no-validate-asm
          -> --wasm-interpret-all -> --no-asm-wasm-lazy-compilation
                                  -> --no-wasm-lazy-compilation

Note that wasm still isn't supported in jitless mode since it generates
code at runtime even with --wasm-interpret-all.

Drive-by: Fail early when trying to compile irregexp code in jitless
mode.

Cq-Include-Trybots: luci.v8.try:v8_linux_arm_lite_rel_ng
Bug: v8:7777
Change-Id: I7f0421f71efeaaeb030ed9ec268d12a659667acf
Reviewed-on: https://chromium-review.googlesource.com/c/1406677Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58820}

src/flag-definitions.h

@@ -1152,6 +1152,19 @@ DEFINE_SIZE_T(mock_arraybuffer_allocator_limit, 0,
 DEFINE_BOOL(jitless, V8_LITE_BOOL,
             "Disable runtime allocation of executable memory.")
 
+// Jitless V8 has a few implications:
+#ifndef V8_LITE_MODE
+// Optimizations (i.e. jitting) are disabled.
+DEFINE_NEG_IMPLICATION(jitless, opt)
+#endif
+// asm.js validation is disabled since it triggers wasm code generation.
+DEFINE_NEG_IMPLICATION(jitless, validate_asm)
+// Wasm is put into interpreter-only mode. We repeat flag implications down
+// here to ensure they're applied correctly by setting the --jitless flag.
+DEFINE_IMPLICATION(jitless, wasm_interpret_all)
+DEFINE_NEG_IMPLICATION(jitless, asm_wasm_lazy_compilation)
+DEFINE_NEG_IMPLICATION(jitless, wasm_lazy_compilation)
+
 // Enable recompilation of function with optimized code.
 DEFINE_BOOL(opt, !V8_LITE_BOOL, "use adaptive optimizations")
 

src/regexp/jsregexp.cc

@@ -6699,6 +6699,8 @@ RegExpEngine::CompilationResult RegExpEngine::Compile(
 
   // Create the correct assembler for the architecture.
 #ifndef V8_INTERPRETED_REGEXP
+  DCHECK(!FLAG_jitless);
+
   // Native regexp implementation.
 
   NativeRegExpMacroAssembler::Mode mode =

test/cctest/test-flags.cc

@@ -196,5 +196,18 @@ TEST(FlagsRemoveIncomplete) {
   CHECK_EQ(2, argc);
 }
 
+TEST(FlagsJitlessImplications) {
+  if (FLAG_jitless) {
+    // Double-check implications work as expected. Our implication system is
+    // fairly primitive and can break easily depending on the implication
+    // definition order in flag-definitions.h.
+    CHECK(!FLAG_opt);
+    CHECK(!FLAG_validate_asm);
+    CHECK(FLAG_wasm_interpret_all);
+    CHECK(!FLAG_asm_wasm_lazy_compilation);
+    CHECK(!FLAG_wasm_lazy_compilation);
+  }
+}
+
 }  // namespace internal
 }  // namespace v8

test/debugger/debugger.status

@@ -126,7 +126,6 @@
 ##############################################################################
 ['lite_mode', {
   # TODO(v8:7777): Re-enable once wasm is supported in jitless mode.
-  'asm-*': [SKIP],
   'debug/wasm/*': [SKIP],
   'wasm-*': [SKIP],
 }], # lite_mode

test/fuzzer/fuzzer.status

@@ -8,6 +8,7 @@
 ['lite_mode', {
   # TODO(v8:7777): Re-enable once wasm is supported in jitless mode.
   'multi_return/*': [SKIP],
+  'wasm_async/*': [SKIP],
   'wasm_compile/*': [SKIP],
 }], # lite_mode
 

test/inspector/inspector.status

@@ -44,7 +44,9 @@
   'type-profiler/type-profile-disable': [SKIP],
 
   # TODO(v8:7777): Re-enable once wasm is supported in jitless mode.
-  'debugger/asm-*': [SKIP],
+  'debugger/asm-js-stack': [SKIP],
+  'debugger/asm-js-breakpoint-before-exec': [SKIP],
+  'debugger/asm-js-breakpoint-during-exec': [SKIP],
   'debugger/wasm-*': [SKIP],
 }],  # 'lite_mode'
 

test/message/message.status

@@ -58,6 +58,9 @@
   # TODO(v8:7777): Re-enable once wasm is supported in jitless mode.
   'fail/wasm-*': [SKIP],
   'wasm-*': [SKIP],
+
+  # Test output requires --validate-asm, which is disabled in jitless mode.
+  'asm-*': [SKIP],
 }], # lite_mode
 
 ]

test/mjsunit/mjsunit.status

@@ -350,35 +350,35 @@
   'spread-large-array': [SKIP],
 
   # TODO(v8:7777): Re-enable once wasm is supported in jitless mode.
-  'asm/*': [SKIP],
   'regress/wasm/*': [SKIP],
   'tools/compiler-trace-flags': [SKIP],
   'wasm/*': [SKIP],
 
   # Other tests that use asm / wasm / optimized code.
-  'compiler/regress-439743': [SKIP],
+  'asm/asm-heap': [SKIP],
+  'asm/asm-validation': [SKIP],
+  'asm/call-stdlib': [SKIP],
+  'asm/call-annotation': [SKIP],
+  'asm/global-imports': [SKIP],
+  'asm/regress-913822': [SKIP],
+  'asm/return-types': [SKIP],
   'regress/regress-599719': [SKIP],
   'regress/regress-6196': [SKIP],
   'regress/regress-6700': [SKIP],
-  'regress/regress-670808': [SKIP],
-  'regress/regress-677685': [SKIP],
   'regress/regress-6838-2': [SKIP],
   'regress/regress-6838-3': [SKIP],
-  'regress/regress-799690': [SKIP],
+
+  # Timeouts in lite / jitless mode.
+  'asm/embenchen/*': [SKIP],
 
   # Tests that generate code at runtime.
   'code-comments': [SKIP],
-  'regress/regress-441099': [SKIP],
   'regress/regress-617526': [SKIP],
-  'regress/regress-618608': [SKIP],
-  'regress/regress-673241': [SKIP],
-  'regress/regress-673297': [SKIP],
   'regress/regress-7893': [SKIP],
   'regress/regress-8377': [SKIP],
   'regress/regress-863810': [SKIP],
   'regress/regress-crbug-721835': [SKIP],
   'regress/regress-crbug-759327': [SKIP],
-  'regress/regress-crbug-762472': [SKIP],
   'regress/regress-crbug-898974': [SKIP],
 }],  # 'lite_mode'