Disable the JS JIT when running in a translated process

https://bugs.webkit.org/show_bug.cgi?id=213478 Reviewed by Saam Barati. Source/JavaScriptCore: * runtime/Options.cpp: (JSC::Options::recomputeDependentOptions): Based on our performance experiements, disable the JavaScript JIT (but not the regular expression, DOM, or Wasm JIT) when running in a translated process. Source/WTF: * wtf/PlatformHave.h: * wtf/TranslatedProcess.h: Added. * WTF.xcodeproj/project.pbxproj: * wtf/CMakeLists.txt: Add a helper function that can be used to determine that the current process is being translated; currently the only case is an x86_64 process running on arm64e. Canonical link: https://commits.webkit.org/226271@main git-svn-id: https://svn.webkit.org/repository/webkit/trunk@263365 268f45cc-cd09-0410-ab3c-d52691b4dbfc
WebKit · Jun 22, 2020 · d2f7f3f · d2f7f3f
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diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,16 @@
+2020-06-22  Tim Horton  <timothy_horton@apple.com>
+
+        Disable the JS JIT when running in a translated process
+        https://bugs.webkit.org/show_bug.cgi?id=213478
+
+        Reviewed by Saam Barati.
+
+        * runtime/Options.cpp:
+        (JSC::Options::recomputeDependentOptions):
+        Based on our performance experiements, disable the JavaScript JIT
+        (but not the regular expression, DOM, or Wasm JIT) when running
+        in a translated process.
+
 2020-06-22  Tim Horton  <timothy_horton@apple.com>
 
         Update macOS version macros

diff --git a/Source/JavaScriptCore/runtime/Options.cpp b/Source/JavaScriptCore/runtime/Options.cpp
@@ -42,6 +42,7 @@
 #include <wtf/Optional.h>
 #include <wtf/OSLogPrintStream.h>
 #include <wtf/StdLibExtras.h>
+#include <wtf/TranslatedProcess.h>
 #include <wtf/text/StringBuilder.h>
 #include <wtf/threads/Signals.h>
 
@@ -428,6 +429,12 @@ void Options::recomputeDependentOptions()
     if (!jitEnabledByDefault() && !Options::useJIT())
         Options::useLLInt() = true;
 
+    if (WTF::isX86BinaryRunningOnARM() && Options::useJIT()) {
+        Options::useBaselineJIT() = false;
+        Options::useDFGJIT() = false;
+        Options::useFTLJIT() = false;
+    }
+
     if (!Options::useWebAssembly())
         Options::useFastTLSForWasmContext() = false;
 

diff --git a/Source/WTF/ChangeLog b/Source/WTF/ChangeLog
@@ -1,3 +1,17 @@
+2020-06-22  Tim Horton  <timothy_horton@apple.com>
+
+        Disable the JS JIT when running in a translated process
+        https://bugs.webkit.org/show_bug.cgi?id=213478
+
+        Reviewed by Saam Barati.
+
+        * wtf/PlatformHave.h:
+        * wtf/TranslatedProcess.h: Added.
+        * WTF.xcodeproj/project.pbxproj:
+        * wtf/CMakeLists.txt:
+        Add a helper function that can be used to determine that the current process
+        is being translated; currently the only case is an x86_64 process running on arm64e.
+
 2020-06-22  Tim Horton  <timothy_horton@apple.com>
 
         Update macOS version macros

diff --git a/Source/WTF/WTF.xcodeproj/project.pbxproj b/Source/WTF/WTF.xcodeproj/project.pbxproj
@@ -361,6 +361,7 @@
 		2CDED0EE18115C38004DBA70 /* RunLoopCF.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = RunLoopCF.cpp; sourceTree = "<group>"; };
 		2CDED0F118115C85004DBA70 /* RunLoop.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = RunLoop.cpp; sourceTree = "<group>"; };
 		2CDED0F218115C85004DBA70 /* RunLoop.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RunLoop.h; sourceTree = "<group>"; };
+		2D1F2F462498F73300C63A83 /* TranslatedProcess.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = TranslatedProcess.h; sourceTree = "<group>"; };
 		2DA442FC24904CA000C9C59D /* OSLogSPI.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = OSLogSPI.h; sourceTree = "<group>"; };
 		304CA4E41375437EBE931D03 /* Markable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Markable.h; sourceTree = "<group>"; };
 		3137E1D7DBD84AC38FAE4D34 /* IndexSet.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = IndexSet.h; sourceTree = "<group>"; };
@@ -1269,6 +1270,7 @@
 				0F7075F31FBF537A00489AF0 /* TimingScope.h */,
 				553071C91C40427200384898 /* TinyLRUCache.h */,
 				0FED67B51B22D4D80066CE15 /* TinyPtrSet.h */,
+				2D1F2F462498F73300C63A83 /* TranslatedProcess.h */,
 				149EF16216BBFE0D000A4331 /* TriState.h */,
 				83FBA93119DF459700F30ADB /* TypeCasts.h */,
 				E360C7642127B85B00C90F0E /* UnalignedAccess.h */,

diff --git a/Source/WTF/wtf/CMakeLists.txt b/Source/WTF/wtf/CMakeLists.txt
@@ -265,6 +265,7 @@ set(WTF_PUBLIC_HEADERS
     TimingScope.h
     TinyLRUCache.h
     TinyPtrSet.h
+    TranslatedProcess.h
     TriState.h
     TypeCasts.h
     URL.h

diff --git a/Source/WTF/wtf/PlatformHave.h b/Source/WTF/wtf/PlatformHave.h
@@ -649,3 +649,7 @@
 #if PLATFORM(IOS_FAMILY) && !PLATFORM(MACCATALYST)
 #define HAVE_FRONTBOARD_SYSTEM_APP_SERVICES 1
 #endif
+
+#if OS(DARWIN) && CPU(X86_64) && ((PLATFORM(MAC) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 101600) || (PLATFORM(MACCATALYST) && __IPHONE_OS_VERSION_MIN_REQUIRED >= 140000))
+#define HAVE_CPU_TRANSLATION_CAPABILITY 1
+#endif
diff --git a/Source/WTF/wtf/TranslatedProcess.h b/Source/WTF/wtf/TranslatedProcess.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2020 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#if HAVE(CPU_TRANSLATION_CAPABILITY)
+#include <System/i386/cpu_capabilities.h>
+#endif
+
+namespace WTF {
+
+inline bool isX86BinaryRunningOnARM()
+{
+#if HAVE(CPU_TRANSLATION_CAPABILITY)
+    return (*(uint64_t*)_COMM_PAGE_CPU_CAPABILITIES64) & kIsTranslated;
+#else
+    return false;
+#endif
+}
+
+}