[no-wasm][flags] Remove wasm flags

This removes all wasm-related flags in no-wasm builds.
We could have made them read-only, but fully removing them actually
forces us to consider the no-wasm case at every use site, which often
hints at further cleanups.

R=jkummerow@chromium.org

Bug: v8:11238
Change-Id: Ic140031a2732975b2a46116a58e26fe49f1f7c8c
Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2759518
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73420}

src/api/api.cc

@@ -5878,7 +5878,9 @@ void V8::GetSharedMemoryStatistics(SharedMemoryStatistics* statistics) {
 
 void V8::SetIsCrossOriginIsolated() {
   i::FLAG_harmony_sharedarraybuffer = true;
+#if V8_ENABLE_WEBASSEMBLY
   i::FLAG_experimental_wasm_threads = true;
+#endif  // V8_ENABLE_WEBASSEMBLY
 }
 
 template <typename ObjectType>

src/codegen/ia32/assembler-ia32.cc

@@ -123,8 +123,10 @@ bool OSHasAVXSupport() {
 }  // namespace
 
 bool CpuFeatures::SupportsWasmSimd128() {
+#if V8_ENABLE_WEBASSEMBLY
   if (IsSupported(SSE4_1)) return true;
   if (FLAG_wasm_simd_ssse3_codegen && IsSupported(SSSE3)) return true;
+#endif  // V8_ENABLE_WEBASSEMBLY
   return false;
 }
 

src/codegen/x64/assembler-x64.cc

@@ -72,8 +72,10 @@ bool OSHasAVXSupport() {
 }  // namespace
 
 bool CpuFeatures::SupportsWasmSimd128() {
+#if V8_ENABLE_WEBASSEMBLY
   if (IsSupported(SSE4_1)) return true;
   if (FLAG_wasm_simd_ssse3_codegen && IsSupported(SSSE3)) return true;
+#endif  // V8_ENABLE_WEBASSEMBLY
   return false;
 }
 

src/execution/isolate.cc

@@ -2546,19 +2546,27 @@ void Isolate::SetAbortOnUncaughtExceptionCallback(
 }
 
 bool Isolate::IsWasmSimdEnabled(Handle<Context> context) {
+#if V8_ENABLE_WEBASSEMBLY
   if (wasm_simd_enabled_callback()) {
     v8::Local<v8::Context> api_context = v8::Utils::ToLocal(context);
     return wasm_simd_enabled_callback()(api_context);
   }
   return FLAG_experimental_wasm_simd;
+#else
+  return false;
+#endif  // V8_ENABLE_WEBASSEMBLY
 }
 
 bool Isolate::AreWasmExceptionsEnabled(Handle<Context> context) {
+#if V8_ENABLE_WEBASSEMBLY
   if (wasm_exceptions_enabled_callback()) {
     v8::Local<v8::Context> api_context = v8::Utils::ToLocal(context);
     return wasm_exceptions_enabled_callback()(api_context);
   }
   return FLAG_experimental_wasm_eh;
+#else
+  return false;
+#endif  // V8_ENABLE_WEBASSEMBLY
 }
 
 Handle<Context> Isolate::GetIncumbentContext() {

src/flags/flag-definitions.h

@@ -448,9 +448,6 @@ DEFINE_IMPLICATION(jitless, regexp_interpret_all)
 DEFINE_NEG_IMPLICATION(jitless, sparkplug)
 DEFINE_NEG_IMPLICATION(jitless, always_sparkplug)
 #endif
-// asm.js validation is disabled since it triggers wasm code generation.
-DEFINE_NEG_IMPLICATION(jitless, validate_asm)
-// --jitless also implies --no-expose-wasm, see InitializeOncePerProcessImpl.
 
 #ifndef V8_TARGET_ARCH_ARM
 // Unsupported on arm. See https://crbug.com/v8/8713.
@@ -824,17 +821,16 @@ DEFINE_BOOL(untrusted_code_mitigations, V8_DEFAULT_UNTRUSTED_CODE_MITIGATIONS,
             "Enable mitigations for executing untrusted code")
 #undef V8_DEFAULT_UNTRUSTED_CODE_MITIGATIONS
 
-// Flags for native WebAssembly.
+// Flags for WebAssembly.
+#if V8_ENABLE_WEBASSEMBLY
+
 DEFINE_BOOL(wasm_generic_wrapper, true,
             "allow use of the generic js-to-wasm wrapper instead of "
             "per-signature wrappers")
-#ifdef V8_ENABLE_WEBASSEMBLY
 DEFINE_BOOL(expose_wasm, true, "expose wasm interface to JavaScript")
-#else
-DEFINE_BOOL_READONLY(expose_wasm, false, "expose wasm interface to JavaScript")
-#endif
 DEFINE_INT(wasm_num_compilation_tasks, 128,
            "maximum number of parallel compilation tasks for wasm")
+DEFINE_VALUE_IMPLICATION(single_threaded, wasm_num_compilation_tasks, 0)
 DEFINE_DEBUG_BOOL(trace_wasm_native_heap, false,
                   "trace wasm native heap events")
 DEFINE_BOOL(wasm_write_protect_code_memory, false,
@@ -843,6 +839,7 @@ DEFINE_DEBUG_BOOL(trace_wasm_serialization, false,
                   "trace serialization/deserialization")
 DEFINE_BOOL(wasm_async_compilation, true,
             "enable actual asynchronous compilation for WebAssembly.compile")
+DEFINE_NEG_IMPLICATION(single_threaded, wasm_async_compilation)
 DEFINE_BOOL(wasm_test_streaming, false,
             "use streaming compilation instead of async compilation for tests")
 DEFINE_UINT(wasm_max_mem_pages, v8::internal::wasm::kSpecMaxMemoryPages,
@@ -890,6 +887,9 @@ DEFINE_INT(wasm_tier_mask_for_testing, 0,
            "bitmask of functions to compile with TurboFan instead of Liftoff")
 
 DEFINE_BOOL(validate_asm, true, "validate asm.js modules before compiling")
+// asm.js validation is disabled since it triggers wasm code generation.
+// --jitless also implies --no-expose-wasm, see InitializeOncePerProcessImpl.
+DEFINE_NEG_IMPLICATION(jitless, validate_asm)
 DEFINE_BOOL(suppress_asm_messages, false,
             "don't emit asm.js related messages (for golden file testing)")
 DEFINE_BOOL(trace_asm_time, false, "print asm.js timing info to the console")
@@ -969,6 +969,28 @@ DEFINE_INT(wasm_max_initial_code_space_reservation, 0,
 DEFINE_BOOL(experimental_wasm_allow_huge_modules, false,
             "allow wasm modules bigger than 1GB, but below ~2GB")
 
+DEFINE_BOOL(trace_wasm, false, "trace wasm function calls")
+
+// Flags for Wasm GDB remote debugging.
+#ifdef V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
+#define DEFAULT_WASM_GDB_REMOTE_PORT 8765
+DEFINE_BOOL(wasm_gdb_remote, false,
+            "enable GDB-remote for WebAssembly debugging")
+DEFINE_NEG_IMPLICATION(wasm_gdb_remote, wasm_tier_up)
+DEFINE_INT(wasm_gdb_remote_port, DEFAULT_WASM_GDB_REMOTE_PORT,
+           "default port for WebAssembly debugging with LLDB.")
+DEFINE_BOOL(wasm_pause_waiting_for_debugger, false,
+            "pause at the first Webassembly instruction waiting for a debugger "
+            "to attach")
+DEFINE_BOOL(trace_wasm_gdb_remote, false, "trace Webassembly GDB-remote server")
+#endif  // V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
+
+// wasm instance management
+DEFINE_DEBUG_BOOL(trace_wasm_instances, false,
+                  "trace creation and collection of wasm instances")
+
+#endif  // V8_ENABLE_WEBASSEMBLY
+
 DEFINE_INT(stress_sampling_allocation_profiler, 0,
            "Enables sampling allocation profiler with X as a sample interval")
 
@@ -1311,7 +1333,6 @@ DEFINE_NEG_NEG_IMPLICATION(inline_new, turbo_allocation_folding)
 
 // codegen-ia32.cc / codegen-arm.cc
 DEFINE_BOOL(trace, false, "trace javascript function calls")
-DEFINE_BOOL(trace_wasm, false, "trace wasm function calls")
 
 // codegen.cc
 DEFINE_BOOL(lazy, true, "use lazy compilation")
@@ -1643,19 +1664,6 @@ DEFINE_BOOL(multi_mapped_mock_allocator, false,
             "Use a multi-mapped mock ArrayBuffer allocator for testing.")
 #endif
 
-// Flags for Wasm GDB remote debugging.
-#ifdef V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
-#define DEFAULT_WASM_GDB_REMOTE_PORT 8765
-DEFINE_BOOL(wasm_gdb_remote, false,
-            "enable GDB-remote for WebAssembly debugging")
-DEFINE_NEG_IMPLICATION(wasm_gdb_remote, wasm_tier_up)
-DEFINE_INT(wasm_gdb_remote_port, DEFAULT_WASM_GDB_REMOTE_PORT,
-           "default port for WebAssembly debugging with LLDB.")
-DEFINE_BOOL(wasm_pause_waiting_for_debugger, false,
-            "pause at the first Webassembly instruction waiting for a debugger "
-            "to attach")
-#endif  // V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
-
 //
 // GDB JIT integration flags.
 //
@@ -1734,14 +1742,6 @@ DEFINE_BOOL(regexp_possessive_quantifier, false,
 // Debugger
 DEFINE_BOOL(print_break_location, false, "print source location on debug break")
 
-// wasm instance management
-DEFINE_DEBUG_BOOL(trace_wasm_instances, false,
-                  "trace creation and collection of wasm instances")
-
-#ifdef V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
-DEFINE_BOOL(trace_wasm_gdb_remote, false, "trace Webassembly GDB-remote server")
-#endif  // V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
-
 //
 // Logging and profiling flags
 //
@@ -1827,7 +1827,9 @@ DEFINE_PERF_PROF_BOOL(
 DEFINE_NEG_IMPLICATION(perf_prof, compact_code_space)
 // TODO(v8:8462) Remove implication once perf supports remapping.
 DEFINE_NEG_IMPLICATION(perf_prof, write_protect_code_memory)
+#if V8_ENABLE_WEBASSEMBLY
 DEFINE_NEG_IMPLICATION(perf_prof, wasm_write_protect_code_memory)
+#endif  // V8_ENABLE_WEBASSEMBLY
 
 // --perf-prof-unwinding-info is available only on selected architectures.
 #if !V8_TARGET_ARCH_ARM && !V8_TARGET_ARCH_ARM64 && !V8_TARGET_ARCH_X64 && \
@@ -1924,8 +1926,6 @@ DEFINE_IMPLICATION(print_all_code, print_regexp_code)
 DEFINE_BOOL(predictable, false, "enable predictable mode")
 DEFINE_IMPLICATION(predictable, single_threaded)
 DEFINE_NEG_IMPLICATION(predictable, memory_reducer)
-DEFINE_VALUE_IMPLICATION(single_threaded, wasm_num_compilation_tasks, 0)
-DEFINE_NEG_IMPLICATION(single_threaded, wasm_async_compilation)
 
 DEFINE_BOOL(predictable_gc_schedule, false,
             "Predictable garbage collection schedule. Fixes heap growing, "

src/flags/flags.cc

@@ -20,7 +20,10 @@
 #include "src/utils/memcopy.h"
 #include "src/utils/ostreams.h"
 #include "src/utils/utils.h"
+
+#if V8_ENABLE_WEBASSEMBLY
 #include "src/wasm/wasm-limits.h"
+#endif  // V8_ENABLE_WEBASSEMBLY
 
 namespace v8 {
 namespace internal {

src/flags/flags.h

@@ -8,7 +8,6 @@
 #include <vector>
 
 #include "src/common/globals.h"
-#include "src/wasm/wasm-limits.h"
 
 namespace v8 {
 namespace internal {

src/init/v8.cc

@@ -127,13 +127,11 @@ void V8::InitializeOncePerProcessImpl() {
   // continue exposing wasm on correctness fuzzers even in jitless mode.
   // TODO(jgruber): Remove this once / if wasm can run without executable
   // memory.
-  if (FLAG_jitless && !FLAG_correctness_fuzzer_suppressions) {
 #if V8_ENABLE_WEBASSEMBLY
+  if (FLAG_jitless && !FLAG_correctness_fuzzer_suppressions) {
     FLAG_expose_wasm = false;
-#else
-    STATIC_ASSERT(!FLAG_expose_wasm);
-#endif
   }
+#endif
 
   if (FLAG_regexp_interpret_all && FLAG_regexp_tier_up) {
     // Turning off the tier-up strategy, because the --regexp-interpret-all and

test/cctest/test-flags.cc

@@ -202,9 +202,11 @@ TEST(FlagsJitlessImplications) {
     // fairly primitive and can break easily depending on the implication
     // definition order in flag-definitions.h.
     CHECK(!FLAG_opt);
+#if V8_ENABLE_WEBASSEMBLY
     CHECK(!FLAG_validate_asm);
     CHECK(!FLAG_asm_wasm_lazy_compilation);
     CHECK(!FLAG_wasm_lazy_compilation);
+#endif  // V8_ENABLE_WEBASSEMBLY
   }
 }