make CharsetEncoder access threadsafe where necessary

Author: tomasstupka

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/capi/PyUnicodeWrappers.java

@@ -64,7 +64,6 @@
 import com.oracle.graal.python.builtins.objects.str.StringNodes.StringMaterializeNode;
 import com.oracle.graal.python.runtime.GilNode;
 import com.oracle.truffle.api.CompilerDirectives;
-import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Cached.Exclusive;
@@ -191,7 +190,7 @@ Object readMember(String member,
      */
     @ExportLibrary(InteropLibrary.class)
     public static class PyUnicodeState extends PyUnicodeWrapper {
-        @CompilationFinal private CharsetEncoder asciiEncoder;
+        private volatile CharsetEncoder asciiEncoder;
 
         public PyUnicodeState(PString delegate) {
             super(delegate);
@@ -280,6 +279,7 @@ private static CharsetEncoder newAsciiEncoder() {
 
         @TruffleBoundary
         private static boolean doCheck(String value, CharsetEncoder asciiEncoder) {
+            asciiEncoder.reset();
             return asciiEncoder.canEncode(value);
         }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/common/CExtContext.java

@@ -171,7 +171,7 @@ public final DynamicObject getSymbolCache() {
      */
     @ValueType
     public static final class ModuleSpec {
-        private static CharsetEncoder asciiEncoder;
+        private volatile CharsetEncoder asciiEncoder;
 
         public final String name;
         public final String path;
@@ -185,7 +185,7 @@ public ModuleSpec(String name, String path, Object originalModuleSpec) {
             this.originalModuleSpec = originalModuleSpec;
         }
 
-        private static CharsetEncoder ensureASCIIEncoder() {
+        private CharsetEncoder ensureASCIIEncoder() {
             if (asciiEncoder == null) {
                 asciiEncoder = StandardCharsets.US_ASCII.newEncoder();
             }
@@ -206,7 +206,9 @@ public String getEncodedName() {
             // Get the short name (substring after last dot)
             String basename = name.substring(name.lastIndexOf('.') + 1);
 
-            if (ensureASCIIEncoder().canEncode(basename)) {
+            boolean canEncode = canEncode(basename);
+
+            if (canEncode) {
                 ascii = true;
             } else {
                 ascii = false;
@@ -221,6 +223,13 @@ public String getEncodedName() {
             return (encodedName = basename.replace('-', '_'));
         }
 
+        @TruffleBoundary
+        private boolean canEncode(String basename) {
+            CharsetEncoder encoder = ensureASCIIEncoder();
+            encoder.reset();
+            return encoder.canEncode(basename);
+        }
+
         @TruffleBoundary
         public String getInitFunctionName(boolean hpy) {
             /*

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/str/StringBuiltins.java

@@ -1917,18 +1917,23 @@ Object doGeneric(VirtualFrame frame, Object self, Object right,
     @Builtin(name = "isascii", minNumOfPositionalArgs = 1)
     @GenerateNodeFactory
     abstract static class IsAsciiNode extends PythonUnaryBuiltinNode {
-        private static final CharsetEncoder asciiEncoder = StandardCharsets.US_ASCII.newEncoder();
+        private final CharsetEncoder asciiEncoder = StandardCharsets.US_ASCII.newEncoder();
 
         @Specialization
-        @TruffleBoundary
         boolean doString(String self) {
-            return asciiEncoder.canEncode(self);
+            return doStringImpl(self);
         }
 
         @Specialization(replaces = "doString")
         boolean doGeneric(Object self,
                         @Cached CastToJavaStringCheckedNode castSelfNode) {
-            return doString(castSelfNode.cast(self, ErrorMessages.REQUIRES_STR_OBJECT_BUT_RECEIVED_P, "isascii", self));
+            return doStringImpl(castSelfNode.cast(self, ErrorMessages.REQUIRES_STR_OBJECT_BUT_RECEIVED_P, "isascii", self));
+        }
+
+        @TruffleBoundary
+        private synchronized boolean doStringImpl(String self) {
+            asciiEncoder.reset();
+            return asciiEncoder.canEncode(self);
         }
     }