Disallow MethodPointer for null targets entirely.

Author: peter-hofer

substratevm/src/com.oracle.svm.core.graal.llvm/src/com/oracle/svm/core/graal/llvm/LLVMNativeImageCodeCache.java

@@ -207,7 +207,7 @@ private void linkCompiledBatches(BatchExecutor executor, DebugContext debug, int
         stackMapDumper.close();
 
         HostedMethod firstMethod = (HostedMethod) getFirstCompilation().getMethods()[0];
-        buildRuntimeMetadata(MethodPointer.factory(firstMethod), WordFactory.signed(textSectionInfo.getCodeSize()));
+        buildRuntimeMetadata(new MethodPointer(firstMethod), WordFactory.signed(textSectionInfo.getCodeSize()));
     }
 
     private void llvmOptimize(DebugContext debug, String outputPath, String inputPath) {

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/InvalidMethodPointerHandler.java

@@ -50,8 +50,8 @@ public final class InvalidMethodPointerHandler {
     public static final Method INVALID_VTABLE_ENTRY_HANDLER_METHOD = ReflectionUtil.lookupMethod(InvalidMethodPointerHandler.class, "invalidVTableEntryHandler");
     public static final String INVALID_VTABLE_ENTRY_MSG = "Fatal error: Virtual method call used an illegal vtable entry that was seen as unused by the static analysis";
 
-    public static final Method METHOD_POINTER_INVALID_HANDLER_METHOD = ReflectionUtil.lookupMethod(InvalidMethodPointerHandler.class, "methodPointerInvalidHandler");
-    public static final String METHOD_POINTER_INVALID_MSG = "Fatal error: Method pointer invoked on a method that is null, was not registered for compilation, or was not seen as invoked by the static analysis";
+    public static final Method METHOD_POINTER_NOT_COMPILED_HANDLER_METHOD = ReflectionUtil.lookupMethod(InvalidMethodPointerHandler.class, "methodPointerNotCompiledHandler");
+    public static final String METHOD_POINTER_NOT_COMPILED_MSG = "Fatal error: Method pointer invoked on a method that was not compiled because it was not seen as invoked by the static analysis nor was it directly registered for compilation";
 
     @StubCallingConvention
     @NeverInline("We need a separate frame that stores all registers")
@@ -63,10 +63,10 @@ private static void invalidVTableEntryHandler() {
 
     @StubCallingConvention
     @NeverInline("We need a separate frame that stores all registers")
-    private static void methodPointerInvalidHandler() {
+    private static void methodPointerNotCompiledHandler() {
         Pointer callerSP = KnownIntrinsics.readCallerStackPointer();
         CodePointer callerIP = KnownIntrinsics.readReturnAddress();
-        failFatally(callerSP, callerIP, METHOD_POINTER_INVALID_MSG);
+        failFatally(callerSP, callerIP, METHOD_POINTER_NOT_COMPILED_MSG);
     }
 
     private static void failFatally(Pointer callerSP, CodePointer callerIP, String message) {

substratevm/src/com.oracle.svm.graal/src/com/oracle/svm/graal/hosted/DeoptimizationFeature.java

@@ -126,6 +126,6 @@ public void beforeCompilation(BeforeCompilationAccess a) {
         CompilationAccessImpl config = (CompilationAccessImpl) a;
         config.registerAsImmutable(ImageSingletons.lookup(DeoptimizationSupport.class));
         HostedMetaAccess metaAccess = config.getMetaAccess();
-        DeoptimizationSupport.setDeoptStubPointer(MethodPointer.factory(metaAccess.lookupJavaMethod(deoptStubMethod)));
+        DeoptimizationSupport.setDeoptStubPointer(new MethodPointer(metaAccess.lookupJavaMethod(deoptStubMethod)));
     }
 }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/classinitialization/ClassInitializationFeature.java

@@ -341,7 +341,7 @@ private static ClassInitializationInfo buildRuntimeInitializationInfo(FeatureImp
             /* Synthesize a VerifyError to be thrown at run time. */
             AnalysisMethod throwVerifyError = access.getMetaAccess().lookupJavaMethod(ExceptionSynthesizer.throwExceptionMethod(VerifyError.class));
             access.registerAsCompiled(throwVerifyError);
-            return new ClassInitializationInfo(MethodPointer.factory(throwVerifyError));
+            return new ClassInitializationInfo(new MethodPointer(throwVerifyError));
         } catch (Throwable t) {
             /*
              * All other linking errors will be reported as NoClassDefFoundError when initialization
@@ -360,7 +360,7 @@ private static ClassInitializationInfo buildRuntimeInitializationInfo(FeatureImp
         if (classInitializer != null) {
             assert classInitializer.getCode() != null;
             access.registerAsCompiled(classInitializer);
-            classInitializerFunction = MethodPointer.factory(classInitializer);
+            classInitializerFunction = new MethodPointer(classInitializer);
         }
         return new ClassInitializationInfo(classInitializerFunction);
     }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/code/CEntryPointCallStubSupport.java

@@ -110,7 +110,7 @@ public AnalysisMethod registerJavaStubForMethod(AnalysisMethod method) {
             if (value == null) {
                 assert !bb.getUniverse().sealed();
                 AnalysisMethod nativeStub = registerStubForMethod(method, () -> CEntryPointData.create(method));
-                CFunctionPointer nativeStubAddress = MethodPointer.factory(nativeStub);
+                CFunctionPointer nativeStubAddress = new MethodPointer(nativeStub);
                 String stubName = SubstrateUtil.uniqueShortName(method);
                 ResolvedJavaType holderClass = bb.getMetaAccess().lookupJavaType(IsolateLeaveStub.class).getWrapped();
                 CEntryPointJavaCallStubMethod stub = new CEntryPointJavaCallStubMethod(method.getWrapped(), stubName, holderClass, nativeStubAddress);

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/code/CEntryPointLiteralFeature.java

@@ -81,7 +81,7 @@ public Object apply(Object source) {
                      * Only during compilation and native image writing, we do the actual
                      * replacement.
                      */
-                    return MethodPointer.factory(hStub);
+                    return new MethodPointer(hStub);
                 }
             }
             return source;

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/LIRNativeImageCodeCache.java

@@ -103,7 +103,7 @@ public void layoutMethods(DebugContext debug, String imageName, BigBang bb, Fork
                 codeCacheSize = NumUtil.roundUp(codeCacheSize + compilation.getTargetCodeSize(), SubstrateOptions.codeAlignment());
             }
 
-            buildRuntimeMetadata(MethodPointer.factory(firstMethod), WordFactory.unsigned(codeCacheSize));
+            buildRuntimeMetadata(new MethodPointer(firstMethod), WordFactory.unsigned(codeCacheSize));
         }
     }
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImage.java

@@ -574,15 +574,10 @@ private void markFunctionRelocationSite(final ProgbitsSectionImpl sectionImpl, f
         assert info.getRelocationSize() == functionPointerRelocationSize : "Function relocation: " + info.getRelocationSize() + " should be " + functionPointerRelocationSize + " bytes.";
         // References to functions are via relocations to the symbol for the function.
         MethodPointer methodPointer = (MethodPointer) info.getTargetObject();
-        HostedMethod target = null;
-        boolean valid = methodPointer.isValid();
-        if (valid) {
-            ResolvedJavaMethod method = methodPointer.getMethod();
-            target = (method instanceof HostedMethod) ? (HostedMethod) method : heap.getUniverse().lookup(method);
-            valid = target.isCompiled();
-        }
-        if (!valid) {
-            target = metaAccess.lookupJavaMethod(InvalidMethodPointerHandler.METHOD_POINTER_INVALID_HANDLER_METHOD);
+        ResolvedJavaMethod method = methodPointer.getMethod();
+        HostedMethod target = (method instanceof HostedMethod) ? (HostedMethod) method : heap.getUniverse().lookup(method);
+        if (!target.isCompiled()) {
+            target = metaAccess.lookupJavaMethod(InvalidMethodPointerHandler.METHOD_POINTER_NOT_COMPILED_HANDLER_METHOD);
         }
         // A reference to a method. Mark the relocation site using the symbol name.
         sectionImpl.markRelocationSite(offset, RelocationKind.getDirect(functionPointerRelocationSize), localSymbolNameForMethod(target), false, 0L);
@@ -976,6 +971,6 @@ final class MethodPointerInvalidHandlerFeature implements Feature {
     @Override
     public void beforeAnalysis(BeforeAnalysisAccess a) {
         FeatureImpl.BeforeAnalysisAccessImpl access = (FeatureImpl.BeforeAnalysisAccessImpl) a;
-        access.registerAsCompiled(InvalidMethodPointerHandler.METHOD_POINTER_INVALID_HANDLER_METHOD);
+        access.registerAsCompiled(InvalidMethodPointerHandler.METHOD_POINTER_NOT_COMPILED_HANDLER_METHOD);
     }
 }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/meta/MethodPointer.java

@@ -26,51 +26,36 @@
 
 import static com.oracle.svm.core.util.VMError.shouldNotReachHere;
 
+import java.util.Objects;
+
 import org.graalvm.nativeimage.c.function.CFunctionPointer;
 import org.graalvm.word.ComparableWord;
 
-import com.oracle.svm.core.InvalidMethodPointerHandler;
-
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 
 /**
  * A pointer to the compiled code of a method.
  */
-public class MethodPointer implements CFunctionPointer {
-    private static final MethodPointer INVALID = new MethodPointer(null);
-
+public final class MethodPointer implements CFunctionPointer {
     private final ResolvedJavaMethod method;
 
-    public static CFunctionPointer factory(ResolvedJavaMethod method) {
-        return (method != null) ? new MethodPointer(method) : INVALID;
-    }
-
-    protected MethodPointer(ResolvedJavaMethod method) {
+    public MethodPointer(ResolvedJavaMethod method) {
+        Objects.requireNonNull(method);
         this.method = method;
     }
 
-    public boolean isValid() {
-        return (method != null);
-    }
-
     public ResolvedJavaMethod getMethod() {
-        assert isValid();
         return method;
     }
 
-    /**
-     * Always {@code false} because even a pointer to {@code null} or to a method that is not
-     * compiled will eventually be replaced by
-     * {@link InvalidMethodPointerHandler#METHOD_POINTER_INVALID_HANDLER_METHOD}.
-     */
     @Override
     public boolean isNull() {
         return false;
     }
 
     @Override
     public boolean isNonNull() {
-        return !isNull();
+        return true;
     }
 
     @Override

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/meta/UniverseBuilder.java

@@ -925,7 +925,7 @@ private void buildHubs() {
                  * We install a CodePointer in the vtable; when generating relocation info, we will
                  * know these point into .text
                  */
-                vtable[idx] = MethodPointer.factory(type.vtable[idx]);
+                vtable[idx] = new MethodPointer(type.vtable[idx]);
             }
 
             // pointer maps in Dynamic Hub