Bug 1577757 - Add a compile-time option for wasm multi-value r=luke

Differential Revision: https://phabricator.services.mozilla.com/D44142

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

js/moz.configure

@@ -566,3 +566,19 @@ js_option('--enable-wasm-private-reftypes',
 
 set_config('WASM_PRIVATE_REFTYPES', depends_if('--enable-wasm-private-reftypes')(lambda x: True))
 set_define('WASM_PRIVATE_REFTYPES', depends_if('--enable-wasm-private-reftypes')(lambda x: True))
+
+
+# Support for the WebAssembly multi-value proposal.
+# =====================================================
+
+@depends(milestone.is_nightly, building_js)
+def default_wasm_multi_value(is_nightly, building_js):
+    return is_nightly and building_js
+
+js_option('--enable-wasm-multi-value',
+          default=default_wasm_multi_value,
+          help='{Enable|Disable} support for the experimental WebAssembly '
+               'multi-value proposal')
+
+set_config('ENABLE_WASM_MULTI_VALUE', depends_if('--enable-wasm-multi-value')(lambda x: True))
+set_define('ENABLE_WASM_MULTI_VALUE', depends_if('--enable-wasm-multi-value')(lambda x: True))

js/src/builtin/TestingFunctions.cpp

@@ -778,6 +778,12 @@ static bool WasmGcEnabled(JSContext* cx, unsigned argc, Value* vp) {
   return true;
 }
 
+static bool WasmMultiValueEnabled(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  args.rval().setBoolean(wasm::HasMultiValueSupport(cx));
+  return true;
+}
+
 static bool WasmDebugSupport(JSContext* cx, unsigned argc, Value* vp) {
   CallArgs args = CallArgsFromVp(argc, vp);
   args.rval().setBoolean(cx->options().wasmBaseline() &&
@@ -6584,6 +6590,10 @@ gc::ZealModeHelpText),
 "wasmGcEnabled()",
 "  Returns a boolean indicating whether the WebAssembly GC types proposal is enabled."),
 
+    JS_FN_HELP("wasmMultiValueEnabled", WasmMultiValueEnabled, 1, 0,
+"wasmMultiValueEnabled()",
+"  Returns a boolean indicating whether the WebAssembly multi-value proposal is enabled."),
+
     JS_FN_HELP("wasmDebugSupport", WasmDebugSupport, 1, 0,
 "wasmDebugSupport()",
 "  Returns a boolean indicating whether the WebAssembly compilers support debugging."),

js/src/jit-test/tests/wasm/binary.js

@@ -232,7 +232,7 @@ assertErrorMessage(() => wasmEval(moduleWithSections([
 
 // Diagnose nonstandard block signature types.
 for (var bad of [0xff, 0, 1, 0x3f])
-    assertErrorMessage(() => wasmEval(moduleWithSections([sigSection([v2vSig]), declSection([0]), bodySection([funcBody({locals:[], body:[BlockCode, bad, EndCode]})])])), CompileError, /invalid inline block type/);
+    assertErrorMessage(() => wasmEval(moduleWithSections([sigSection([v2vSig]), declSection([0]), bodySection([funcBody({locals:[], body:[BlockCode, bad, EndCode]})])])), CompileError, /invalid .*block type/);
 
 // Ensure all invalid opcodes rejected
 for (let op of undefinedOpcodes) {

js/src/wasm/WasmJS.cpp

@@ -87,6 +87,19 @@ bool wasm::HasGcSupport(JSContext* cx) {
 #endif
 }
 
+bool wasm::HasMultiValueSupport(JSContext* cx) {
+#ifdef ENABLE_WASM_CRANELIFT
+  if (cx->options().wasmCranelift()) {
+    return false;
+  }
+#endif
+#ifdef ENABLE_WASM_MULTI_VALUE
+  return true;
+#else
+  return false;
+#endif
+}
+
 bool wasm::HasCompilerSupport(JSContext* cx) {
 #if !MOZ_LITTLE_ENDIAN || defined(JS_CODEGEN_NONE)
   return false;

js/src/wasm/WasmJS.h

@@ -69,6 +69,11 @@ bool HasReftypesSupport(JSContext* cx);
 
 bool HasGcSupport(JSContext* cx);
 
+// Returns true if WebAssembly as configured by compile-time flags and run-time
+// options can support multi-value block and function returns (evolving).
+
+bool HasMultiValueSupport(JSContext* cx);
+
 // Compiles the given binary wasm module given the ArrayBufferObject
 // and links the module's imports with the given import object.