Bug 1660944: Use Cranelift by default for wasm compilation on aarch64…

…; r=lth Differential Revision: https://phabricator.services.mozilla.com/D88396
iaxat · Sep 2, 2020 · 52fff50 · 52fff50
1 parent fdf392a
commit 52fff50
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Showing 3 changed files with 33 additions and 10 deletions.
diff --git a/js/moz.configure b/js/moz.configure
@@ -478,14 +478,16 @@ set_config('MOZ_RUST_SIMD', rust_simd)
 set_define('MOZ_RUST_SIMD', rust_simd)
 
 
-# Experimental support for wasm code generation with Cranelift
-#
-# Note, you may have to disable features not supported by Cranelift
-# (multi-value, threads) to make Cranelift actually available
+# Support for wasm code generation with Cranelift
 # ==============================================================
 
+@depends(milestone.is_nightly, target, simulator)
+def cranelift_default(is_nightly, target, simulator):
+    if is_nightly or target.cpu == 'aarch64' or simulator.arm64:
+        return True
+
 js_option('--enable-cranelift',
-          default=milestone.is_nightly,
+          default=cranelift_default,
           help='{Enable|Disable} Cranelift code generator for wasm')
 
 set_config('ENABLE_WASM_CRANELIFT', depends_if('--enable-cranelift')(lambda x: True))

diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
@@ -10199,22 +10199,30 @@ static bool SetContextOptions(JSContext* cx, const OptionParser& op) {
   // Default values for wasm.
   enableWasm = true;
   enableWasmBaseline = true;
+#ifdef JS_CODEGEN_ARM64
+  enableWasmCranelift = true;
+#else
   enableWasmIon = true;
+#endif
   if (const char* str = op.getStringOption("wasm-compiler")) {
     if (strcmp(str, "none") == 0) {
       enableWasm = false;
     } else if (strcmp(str, "baseline") == 0) {
       // Baseline is enabled by default.
       enableWasmIon = false;
+      enableWasmCranelift = false;
     } else if (strcmp(str, "ion") == 0) {
-      // Ion is enabled by default.
       enableWasmBaseline = false;
+      enableWasmIon = true;
+      enableWasmCranelift = false;
     } else if (strcmp(str, "cranelift") == 0) {
       enableWasmBaseline = false;
       enableWasmIon = false;
       enableWasmCranelift = true;
     } else if (strcmp(str, "baseline+ion") == 0) {
-      // Default.
+      // Baseline is enabled by default.
+      enableWasmIon = true;
+      enableWasmCranelift = false;
     } else if (strcmp(str, "baseline+cranelift") == 0) {
       // Baseline is enabled by default.
       enableWasmIon = false;

diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
@@ -1090,11 +1090,24 @@ pref("javascript.options.asmjs",                  true);
 pref("javascript.options.wasm",                   true);
 pref("javascript.options.wasm_trustedprincipals", true);
 pref("javascript.options.wasm_verbose",           false);
-pref("javascript.options.wasm_ionjit",            true);
 pref("javascript.options.wasm_baselinejit",       true);
-#ifdef ENABLE_WASM_CRANELIFT
-  pref("javascript.options.wasm_cranelift",       false);
+
+// On aarch64, Cranelift is the optimizing tier used by default for wasm
+// compilation, and Ion is not available.
+// On every other tier-1 platform, Ion is the default, and Cranelift is
+// disabled.
+#ifdef _ARM64_
+  #ifdef ENABLE_WASM_CRANELIFT
+    pref("javascript.options.wasm_cranelift",     true);
+  #endif
+  pref("javascript.options.wasm_ionjit",          false);
+#else
+  #ifdef ENABLE_WASM_CRANELIFT
+    pref("javascript.options.wasm_cranelift",     false);
+  #endif
+  pref("javascript.options.wasm_ionjit",          true);
 #endif
+
 #ifdef ENABLE_WASM_REFTYPES
   pref("javascript.options.wasm_reftypes",        true);
   pref("javascript.options.wasm_gc",              false);