Attempt to disable JIT on Android with JSC_useJIT=false to avoid crash in JSValueUnprotect

Author: marcprux

Sources/SkipScript/JSContext.swift

@@ -16,18 +16,27 @@ let JavaScriptCore: JavaScriptCoreLibrary = JavaScriptCoreLibrary.instance
 
 public typealias ExceptionPtr = UnsafeMutablePointer<JSValueRef?>
 
+/// JIT needs to be disabled on Android to avoid random crashes in `JSValueUnprotect`
+/// See: https://github.com/WebKit/WebKit/blob/main/Tools/Scripts/run-jsc-benchmarks
+private func disableJIT() {
+    // JSC_useWasmIPInt=0 JSC_useWasmLLInt=1 JSC_useWebAssembly=1 JSC_useJIT=0
+    setenv("JSC_useJIT", "false", 1)
+}
+
 /// A context for evaluating JavaScipt.
 public class JSContext {
     public let context: JSContextRef
     public private(set) var exception: JSValue? = nil
     private var tryingRecursionGuard = false
 
     public init(jsGlobalContextRef context: JSContextRef) {
+        disableJIT()
         self.context = context
         JavaScriptCore.JSGlobalContextRetain(context)
     }
 
     public init() {
+        disableJIT()
         self.context = JavaScriptCore.JSGlobalContextCreate(nil)
     }
 
@@ -544,8 +553,24 @@ public class JSValue {
     }
 
     deinit {
-        // this has been seen to raise an exception on the Android emulator:
+        // this has been seen to raise an exception on the Android emulator when not setting `JSC_useJIT`:
         // java.util.concurrent.TimeoutException: skip.script.JSValue.finalize() timed out after 10 seconds
+        // it has also led to crashes:
+        /*
+         02-06 14:33:12.996  2016  2016 F DEBUG   :       #00 pc 000000000028ff90  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk!libjsc.so (offset 0x2aa8000) (JSValueUnprotect+16) (BuildId: ca8f87b98242c913dfdaa146cce2a24b070804a2)
+         02-06 14:33:12.996  2016  2016 F DEBUG   :       #01 pc 0000000000012051  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk (offset 0x2a88000) (BuildId: 93b2f9545d27a84372ca7fba3b2b473c2f9c6edd)
+         02-06 14:33:12.996  2016  2016 F DEBUG   :       #02 pc 0000000000011032  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk (offset 0x2a88000) (BuildId: 93b2f9545d27a84372ca7fba3b2b473c2f9c6edd)
+         02-06 14:33:12.996  2016  2016 F DEBUG   :       #03 pc 000000000001174b  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk (offset 0x2a88000) (ffi_call+219) (BuildId: 93b2f9545d27a84372ca7fba3b2b473c2f9c6edd)
+         02-06 14:33:12.996  2016  2016 F DEBUG   :       #04 pc 0000000000007264  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk (offset 0x2a88000) (BuildId: 93b2f9545d27a84372ca7fba3b2b473c2f9c6edd)
+         02-06 14:33:12.996  2016  2016 F DEBUG   :       #05 pc 0000000000011a17  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk (offset 0x2a88000) (BuildId: 93b2f9545d27a84372ca7fba3b2b473c2f9c6edd)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #06 pc 00000000000121e7  /data/app/~~HElSLsP99NS9XFzsCODJmA==/skip.script.test-v4AHg-MWsLEjjHmmm5YC7w==/base.apk (offset 0x2a88000) (BuildId: 93b2f9545d27a84372ca7fba3b2b473c2f9c6edd)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #07 pc 000000000200d1de  /memfd:jit-cache (deleted) (offset 0x2000000) (art_jni_trampoline+222)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #08 pc 000000000202ee59  /memfd:jit-cache (deleted) (offset 0x2000000) (skip.script.JSValue.finalize+121)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #09 pc 000000000202f070  /memfd:jit-cache (deleted) (offset 0x2000000) (java.lang.Daemons$FinalizerDaemon.doFinalize+112)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #10 pc 000000000202b42f  /memfd:jit-cache (deleted) (offset 0x2000000) (java.lang.Daemons$FinalizerDaemon.runInternal+511)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #11 pc 0000000000185e6b  /apex/com.android.art/lib64/libart.so (art_quick_osr_stub+27) (BuildId: 1dfb27162fe62a7ac7a10ea361233369)
+         02-06 14:33:12.997  2016  2016 F DEBUG   :       #12 pc 00000000003d27ba  /apex/com.android.art/lib64/libart.so (art::jit::Jit::MaybeDoOnStackReplacement(art::Thread*, art::ArtMethod*, unsigned int, int, art::JValue*)+410) (BuildId: 1dfb27162fe62a7ac7a10ea361233369)
+         */
         JavaScriptCore.JSValueUnprotect(context.context, value)
     }
 }