Bug 1620986 - Introduce run-time switch for multi-value. r=bbouvier,wingo

This adds a JS shell command line argument to disable multi-value (if
it is enabled at compile time) and an about:config option to do the
same in the browser.

At this time, multi-values are not enabled in the browser, so the
about:config option is not visible.

Differential Revision: https://phabricator.services.mozilla.com/D67465

--HG--
extra : moz-landing-system : lando

js/public/ContextOptions.h

@@ -26,6 +26,7 @@ class JS_PUBLIC_API ContextOptions {
         wasmIon_(true),
         wasmCranelift_(false),
         wasmGc_(false),
+        wasmMultiValue_(false),
         testWasmAwaitTier2_(false),
 #ifdef ENABLE_WASM_BIGINT
         enableWasmBigInt_(true),
@@ -110,6 +111,10 @@ class JS_PUBLIC_API ContextOptions {
   // Defined out-of-line because it depends on a compile-time option
   ContextOptions& setWasmGc(bool flag);
 
+  bool wasmMultiValue() const { return wasmMultiValue_; }
+  // Defined out-of-line because it depends on a compile-time option
+  ContextOptions& setWasmMultiValue(bool flag);
+
   bool throwOnAsmJSValidationFailure() const {
     return throwOnAsmJSValidationFailure_;
   }
@@ -197,6 +202,7 @@ class JS_PUBLIC_API ContextOptions {
     setWasmBaseline(false);
     setWasmIon(false);
     setWasmGc(false);
+    setWasmMultiValue(false);
   }
 
  private:
@@ -208,6 +214,7 @@ class JS_PUBLIC_API ContextOptions {
   bool wasmIon_ : 1;
   bool wasmCranelift_ : 1;
   bool wasmGc_ : 1;
+  bool wasmMultiValue_ : 1;
   bool testWasmAwaitTier2_ : 1;
 #ifdef ENABLE_WASM_BIGINT
   bool enableWasmBigInt_ : 1;

js/src/jsapi.cpp

@@ -428,6 +428,13 @@ JS::ContextOptions& JS::ContextOptions::setWasmGc(bool flag) {
   return *this;
 }
 
+JS::ContextOptions& JS::ContextOptions::setWasmMultiValue(bool flag) {
+#ifdef ENABLE_WASM_MULTI_VALUE
+  wasmMultiValue_ = flag;
+#endif
+  return *this;
+}
+
 JS::ContextOptions& JS::ContextOptions::setFuzzing(bool flag) {
 #ifdef FUZZING
   fuzzing_ = flag;

js/src/shell/js.cpp

@@ -493,6 +493,9 @@ bool shell::enableWasmCranelift = false;
 #ifdef ENABLE_WASM_GC
 bool shell::enableWasmGc = false;
 #endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+bool shell::enableWasmMultiValue = true;
+#endif
 bool shell::enableWasmVerbose = false;
 bool shell::enableTestWasmAwaitTier2 = false;
 #ifdef ENABLE_WASM_BIGINT
@@ -10347,6 +10350,9 @@ static bool SetContextOptions(JSContext* cx, const OptionParser& op) {
 
 #ifdef ENABLE_WASM_GC
   enableWasmGc = op.getBoolOption("wasm-gc");
+#endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+  enableWasmMultiValue = !op.getBoolOption("no-wasm-multi-value");
 #endif
   enableWasmVerbose = op.getBoolOption("wasm-verbose");
   enableTestWasmAwaitTier2 = op.getBoolOption("test-wasm-await-tier2");
@@ -10375,6 +10381,9 @@ static bool SetContextOptions(JSContext* cx, const OptionParser& op) {
 #endif
 #ifdef ENABLE_WASM_GC
       .setWasmGc(enableWasmGc)
+#endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+      .setWasmMultiValue(enableWasmMultiValue)
 #endif
       .setWasmVerbose(enableWasmVerbose)
       .setTestWasmAwaitTier2(enableTestWasmAwaitTier2)
@@ -10721,6 +10730,9 @@ static void SetWorkerContextOptions(JSContext* cx) {
 #ifdef ENABLE_WASM_GC
       .setWasmGc(enableWasmGc)
 #endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+      .setWasmMultiValue(enableWasmMultiValue)
+#endif
 #ifdef ENABLE_WASM_BIGINT
       .setWasmBigIntEnabled(enableWasmBigInt)
 #endif
@@ -11152,6 +11164,13 @@ int main(int argc, char** argv, char** envp) {
 #else
       !op.addBoolOption('\0', "wasm-gc", "No-op") ||
 #endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+      !op.addBoolOption('\0', "no-wasm-multi-value",
+                        "Disable wasm multi-value features") ||
+#else
+      !op.addBoolOption('\0', "no-wasm-multi-value", "No-op") ||
+#endif
+
       !op.addBoolOption('\0', "no-native-regexp",
                         "Disable native regexp compilation") ||
       !op.addBoolOption('\0', "no-unboxed-objects",

js/src/shell/jsshell.h

@@ -110,6 +110,9 @@ extern bool enableWasmCranelift;
 #ifdef ENABLE_WASM_GC
 extern bool enableWasmGc;
 #endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+extern bool enableWasmMultiValue;
+#endif
 extern bool enableWasmVerbose;
 extern bool enableTestWasmAwaitTier2;
 #ifdef ENABLE_WASM_BIGINT

js/src/wasm/WasmJS.cpp

@@ -67,7 +67,7 @@ extern mozilla::Atomic<bool> fuzzingSafe;
 
 static inline bool WasmMultiValueFlag(JSContext* cx) {
 #ifdef ENABLE_WASM_MULTI_VALUE
-  return true;
+  return cx->options().wasmMultiValue();
 #else
   return false;
 #endif

js/xpconnect/src/XPCJSContext.cpp

@@ -910,6 +910,10 @@ static void ReloadPrefsCallback(const char* pref, void* aXpccx) {
 #endif
 #ifdef ENABLE_WASM_GC
   bool useWasmGc = Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm_gc");
+#endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+  bool useWasmMultiValue =
+      Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm_multi_value");
 #endif
   bool useWasmVerbose = Preferences::GetBool(JS_OPTIONS_DOT_STR "wasm_verbose");
   bool throwOnAsmJSValidationFailure = Preferences::GetBool(
@@ -966,6 +970,9 @@ static void ReloadPrefsCallback(const char* pref, void* aXpccx) {
 #endif
 #ifdef ENABLE_WASM_GC
       .setWasmGc(useWasmGc)
+#endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+      .setWasmMultiValue(useWasmMultiValue)
 #endif
       .setWasmVerbose(useWasmVerbose)
       .setThrowOnAsmJSValidationFailure(throwOnAsmJSValidationFailure)

modules/libpref/init/all.js

@@ -1121,6 +1121,9 @@ pref("javascript.options.wasm_baselinejit",       true);
 #ifdef ENABLE_WASM_REFTYPES
   pref("javascript.options.wasm_gc",              false);
 #endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+  pref("javascript.options.wasm_multi_value",     true);
+#endif
 pref("javascript.options.native_regexp",    true);
 pref("javascript.options.parallel_parsing", true);
 // Async stacks instrumentation adds overhead that is only