[GR-68174] Use correct assembler in FFM API upcall stub generation.

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/asm/Assembler.java

@@ -198,8 +198,24 @@ public void emitString(String s, int pos) {
      *            including) {@code position()} is returned
      * @return the data in this buffer or a trimmed copy if {@code trimmedCopy} is {@code true}
      */
-    public byte[] close(boolean trimmedCopy) {
+    public final byte[] close(boolean trimmedCopy) {
+        return closeAligned(trimmedCopy, 0);
+    }
+
+    /**
+     * Closes this assembler. No extra data can be written to this assembler after this call.
+     *
+     * @param trimmedCopy if {@code true}, then a copy of the underlying byte array up to (but not
+     *            including) {@code position()} is returned
+     * @param alignment if {@code > 0}, then align the end of the code buffer with NOPs to the
+     *            specified alignment
+     * @return the data in this buffer or a trimmed copy if {@code trimmedCopy} is {@code true}
+     */
+    public byte[] closeAligned(boolean trimmedCopy, int alignment) {
         checkAndClearLabelsWithPatches();
+        if (alignment > 0 && position() % alignment != 0) {
+            this.align(alignment);
+        }
         finalCodeSize = position();
         return codeBuffer.close(trimmedCopy);
     }

substratevm/src/com.oracle.svm.core.foreign/src/com/oracle/svm/core/foreign/AbiUtils.java

@@ -52,13 +52,17 @@
 import org.graalvm.nativeimage.Platforms;
 import org.graalvm.word.Pointer;
 
+import com.oracle.svm.core.BuildPhaseProvider.AfterAnalysis;
+import com.oracle.svm.core.SubstrateControlFlowIntegrity;
 import com.oracle.svm.core.SubstrateTargetDescription;
 import com.oracle.svm.core.aarch64.SubstrateAArch64MacroAssembler;
 import com.oracle.svm.core.config.ConfigurationValues;
 import com.oracle.svm.core.foreign.AbiUtils.Adapter.Adaptation;
 import com.oracle.svm.core.graal.code.AssignedLocation;
+import com.oracle.svm.core.graal.code.SubstrateBackendWithAssembler;
 import com.oracle.svm.core.headers.LibC;
 import com.oracle.svm.core.headers.WindowsAPIs;
+import com.oracle.svm.core.heap.UnknownPrimitiveField;
 import com.oracle.svm.core.util.BasedOnJDKClass;
 import com.oracle.svm.core.util.BasedOnJDKFile;
 import com.oracle.svm.core.util.VMError;
@@ -69,8 +73,8 @@
 import jdk.graal.compiler.asm.aarch64.AArch64Address;
 import jdk.graal.compiler.asm.aarch64.AArch64MacroAssembler;
 import jdk.graal.compiler.asm.amd64.AMD64Address;
-import jdk.graal.compiler.asm.amd64.AMD64Assembler;
 import jdk.graal.compiler.asm.amd64.AMD64BaseAssembler;
+import jdk.graal.compiler.asm.amd64.AMD64MacroAssembler;
 import jdk.graal.compiler.graph.Node;
 import jdk.graal.compiler.nodes.ValueNode;
 import jdk.graal.compiler.nodes.calc.AddNode;
@@ -671,11 +675,40 @@ public record Registers(Register methodHandle, Register isolate) {
 
     public abstract int trampolineSize();
 
-    record TrampolineTemplate(byte[] assemblyTemplate, int isolateOffset, int methodHandleOffset, int stubOffset) {
+    public static class TrampolineTemplate {
+
+        private final byte[] assemblyTemplate;
+
+        /*
+         * These fields will only be filled after the analysis, when an assembler is available.
+         * Prevent optimizations that constant-fold these fields already during analysis.
+         */
+
+        @UnknownPrimitiveField(availability = AfterAnalysis.class) //
+        private int isolateOffset;
+        @UnknownPrimitiveField(availability = AfterAnalysis.class) //
+        private int methodHandleOffset;
+        @UnknownPrimitiveField(availability = AfterAnalysis.class) //
+        private int stubOffset;
+
+        public TrampolineTemplate(byte[] assemblyTemplate) {
+            this.assemblyTemplate = assemblyTemplate;
+        }
+
+        @Platforms(Platform.HOSTED_ONLY.class)
+        public void setTemplate(byte[] code, int isolateOff, int methodHandleOff, int stubOff) {
+            assert code.length == this.assemblyTemplate.length;
+            System.arraycopy(code, 0, this.assemblyTemplate, 0, this.assemblyTemplate.length);
+            this.isolateOffset = isolateOff;
+            this.methodHandleOffset = methodHandleOff;
+            this.stubOffset = stubOff;
+        }
+
         public Pointer write(Pointer at, Isolate isolate, Word methodHandle, Word stubPointer) {
             for (int i = 0; i < assemblyTemplate.length; ++i) {
                 at.writeByte(i, assemblyTemplate[i]);
             }
+
             at.writeWord(isolateOffset, isolate);
             at.writeWord(methodHandleOffset, methodHandle);
             at.writeWord(stubOffset, stubPointer);
@@ -685,7 +718,7 @@ public Pointer write(Pointer at, Isolate isolate, Word methodHandle, Word stubPo
     }
 
     @Platforms(Platform.HOSTED_ONLY.class)
-    abstract TrampolineTemplate generateTrampolineTemplate();
+    abstract void generateTrampolineTemplate(SubstrateBackendWithAssembler<?> backend, TrampolineTemplate template);
 }
 
 class ABIs {
@@ -740,8 +773,8 @@ public int trampolineSize() {
         }
 
         @Override
-        public TrampolineTemplate generateTrampolineTemplate() {
-            return null;
+        public void generateTrampolineTemplate(SubstrateBackendWithAssembler<?> backend, TrampolineTemplate template) {
+            fail();
         }
 
         @Override
@@ -812,8 +845,8 @@ public int trampolineSize() {
 
         @Platforms(Platform.HOSTED_ONLY.class)
         @Override
-        public TrampolineTemplate generateTrampolineTemplate() {
-            AArch64MacroAssembler masm = new SubstrateAArch64MacroAssembler(ConfigurationValues.getTarget());
+        public void generateTrampolineTemplate(SubstrateBackendWithAssembler<?> backend, TrampolineTemplate template) {
+            AArch64MacroAssembler masm = (AArch64MacroAssembler) backend.createAssemblerNoOptions();
 
             Register mhRegister = upcallSpecialArgumentsRegisters().methodHandle();
             Register isolateRegister = upcallSpecialArgumentsRegisters().isolate();
@@ -849,12 +882,11 @@ public TrampolineTemplate generateTrampolineTemplate() {
             masm.jmp(scratch);
 
             assert trampolineSize() >= masm.position();
-            masm.align(trampolineSize());
 
-            byte[] assembly = masm.close(true);
+            byte[] assembly = masm.closeAligned(true, trampolineSize());
             assert assembly.length == trampolineSize();
 
-            return new TrampolineTemplate(assembly, posIsolate, posMHArray, posCallTarget);
+            template.setTemplate(assembly, posIsolate, posMHArray, posCallTarget);
         }
 
         @BasedOnJDKFile("https://github.com/openjdk/jdk/blob/jdk-25+13/src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/CallArranger.java#L195")
@@ -974,9 +1006,9 @@ public int trampolineSize() {
 
         @Platforms(Platform.HOSTED_ONLY.class)
         @Override
-        public TrampolineTemplate generateTrampolineTemplate() {
+        public void generateTrampolineTemplate(SubstrateBackendWithAssembler<?> backend, TrampolineTemplate template) {
             // Generate the trampoline
-            AMD64Assembler asm = new AMD64Assembler(ConfigurationValues.getTarget());
+            AMD64MacroAssembler asm = (AMD64MacroAssembler) backend.createAssemblerNoOptions();
             var odas = new ArrayList<AMD64BaseAssembler.OperandDataAnnotation>(3);
             // Collect the positions of the address in the movq instructions.
             asm.setCodePatchingAnnotationConsumer(ca -> {
@@ -988,6 +1020,7 @@ public TrampolineTemplate generateTrampolineTemplate() {
             Register mhRegister = upcallSpecialArgumentsRegisters().methodHandle();
             Register isolateRegister = upcallSpecialArgumentsRegisters().isolate();
 
+            asm.maybeEmitIndirectTargetMarker();
             /* Store isolate in the assigned register */
             asm.movq(isolateRegister, 0L, true);
             /* r10 points in the mh array */
@@ -997,17 +1030,21 @@ public TrampolineTemplate generateTrampolineTemplate() {
             /* rax contains the stub address */
             asm.movq(rax, 0L, true);
             /* executes the stub */
-            asm.jmp(new AMD64Address(rax, 0));
+            if (SubstrateControlFlowIntegrity.useSoftwareCFI()) {
+                asm.movq(rax, new AMD64Address(rax, 0));
+                asm.jmp(rax);
+            } else {
+                asm.jmp(new AMD64Address(rax, 0));
+            }
 
             assert trampolineSize() - asm.position() >= 0;
-            asm.nop(trampolineSize() - asm.position());
 
-            byte[] assembly = asm.close(true);
+            byte[] assembly = asm.closeAligned(true, trampolineSize());
             assert assembly.length == trampolineSize();
             assert odas.size() == 3;
             assert odas.stream().allMatch(oda -> oda.operandSize == 8);
 
-            return new TrampolineTemplate(assembly, odas.get(0).operandPosition, odas.get(1).operandPosition, odas.get(2).operandPosition);
+            template.setTemplate(assembly, odas.get(0).operandPosition, odas.get(1).operandPosition, odas.get(2).operandPosition);
         }
     }
 

substratevm/src/com.oracle.svm.core.foreign/src/com/oracle/svm/core/foreign/ForeignFunctionsRuntime.java

@@ -58,7 +58,9 @@
 import com.oracle.svm.core.SubstrateUtil;
 import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.c.InvokeJavaFunctionPointer;
+import com.oracle.svm.core.foreign.AbiUtils.TrampolineTemplate;
 import com.oracle.svm.core.foreign.phases.SubstrateOptimizeSharedArenaAccessPhase.OptimizeSharedArenaConfig;
+import com.oracle.svm.core.graal.code.SubstrateBackendWithAssembler;
 import com.oracle.svm.core.headers.LibC;
 import com.oracle.svm.core.headers.WindowsAPIs;
 import com.oracle.svm.core.image.DisallowedImageHeapObjects.DisallowedObjectReporter;
@@ -99,7 +101,12 @@ public static ForeignFunctionsRuntime singleton() {
 
     @Platforms(Platform.HOSTED_ONLY.class)
     public ForeignFunctionsRuntime(AbiUtils abiUtils) {
-        this.trampolineTemplate = abiUtils.generateTrampolineTemplate();
+        this.trampolineTemplate = new TrampolineTemplate(new byte[abiUtils.trampolineSize()]);
+    }
+
+    @Platforms(Platform.HOSTED_ONLY.class)
+    public void generateTrampolineTemplate(SubstrateBackendWithAssembler<?> backend) {
+        AbiUtils.singleton().generateTrampolineTemplate(backend, this.trampolineTemplate);
     }
 
     public static boolean areFunctionCallsSupported() {

substratevm/src/com.oracle.svm.core.foreign/src/com/oracle/svm/core/foreign/TrampolineSet.java

@@ -159,7 +159,7 @@ private Pointer prepareTrampolines(PinnedObject mhsArray, PinnedObject stubsArra
             VMError.guarantee(it.belowOrEqual(end), "Not enough memory was allocated to hold trampolines");
         }
 
-        VMError.guarantee(VirtualMemoryProvider.get().protect(page, pageSize, VirtualMemoryProvider.Access.EXECUTE) == 0,
+        VMError.guarantee(VirtualMemoryProvider.get().protect(page, pageSize, VirtualMemoryProvider.Access.READ | VirtualMemoryProvider.Access.EXECUTE) == 0,
                         "Error when making the trampoline allocation executable");
 
         /*

substratevm/src/com.oracle.svm.core.graal.aarch64/src/com/oracle/svm/core/graal/aarch64/SubstrateAArch64Backend.java

@@ -55,7 +55,7 @@
 import com.oracle.svm.core.graal.code.AssignedLocation;
 import com.oracle.svm.core.graal.code.PatchConsumerFactory;
 import com.oracle.svm.core.graal.code.SharedCompilationResult;
-import com.oracle.svm.core.graal.code.SubstrateBackend;
+import com.oracle.svm.core.graal.code.SubstrateBackendWithAssembler;
 import com.oracle.svm.core.graal.code.SubstrateCallingConvention;
 import com.oracle.svm.core.graal.code.SubstrateCallingConventionKind;
 import com.oracle.svm.core.graal.code.SubstrateCallingConventionType;
@@ -194,7 +194,7 @@
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 import jdk.vm.ci.meta.Value;
 
-public class SubstrateAArch64Backend extends SubstrateBackend implements LIRGenerationProvider {
+public class SubstrateAArch64Backend extends SubstrateBackendWithAssembler<SubstrateAArch64MacroAssembler> implements LIRGenerationProvider {
 
     protected static CompressEncoding getCompressEncoding() {
         return ImageSingletons.lookup(CompressEncoding.class);
@@ -1564,4 +1564,9 @@ public LIRGenerationResult newLIRGenerationResult(CompilationIdentifier compilat
     public BasePhase<CoreProviders> newAddressLoweringPhase(CodeCacheProvider codeCache) {
         return new AddressLoweringByUsePhase(new AArch64AddressLoweringByUse(createLirKindTool(), false));
     }
+
+    @Override
+    public SubstrateAArch64MacroAssembler createAssembler(OptionValues options) {
+        return new SubstrateAArch64MacroAssembler(getTarget());
+    }
 }

substratevm/src/com.oracle.svm.core.graal.amd64/src/com/oracle/svm/core/graal/amd64/SubstrateAMD64Backend.java

@@ -47,7 +47,6 @@
 import java.util.List;
 import java.util.function.BiConsumer;
 
-import org.graalvm.collections.EconomicMap;
 import org.graalvm.nativeimage.ImageSingletons;
 
 import com.oracle.svm.core.CPUFeatureAccess;
@@ -67,7 +66,7 @@
 import com.oracle.svm.core.graal.code.PatchConsumerFactory;
 import com.oracle.svm.core.graal.code.SharedCompilationResult;
 import com.oracle.svm.core.graal.code.StubCallingConvention;
-import com.oracle.svm.core.graal.code.SubstrateBackend;
+import com.oracle.svm.core.graal.code.SubstrateBackendWithAssembler;
 import com.oracle.svm.core.graal.code.SubstrateCallingConvention;
 import com.oracle.svm.core.graal.code.SubstrateCallingConventionKind;
 import com.oracle.svm.core.graal.code.SubstrateCallingConventionType;
@@ -222,7 +221,7 @@
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 import jdk.vm.ci.meta.Value;
 
-public class SubstrateAMD64Backend extends SubstrateBackend implements LIRGenerationProvider {
+public class SubstrateAMD64Backend extends SubstrateBackendWithAssembler<AMD64MacroAssembler> implements LIRGenerationProvider {
 
     protected static CompressEncoding getCompressEncoding() {
         return ImageSingletons.lookup(CompressEncoding.class);
@@ -1922,6 +1921,7 @@ public CompilationResultBuilder newCompilationResultBuilder(LIRGenerationResult
         return crb;
     }
 
+    @Override
     protected AMD64MacroAssembler createAssembler(OptionValues options) {
         return new AMD64MacroAssembler(getTarget(), options, true);
     }
@@ -1961,11 +1961,6 @@ public void emitCode(CompilationResultBuilder crb, ResolvedJavaMethod installedC
         }
     }
 
-    public AMD64Assembler createAssemblerNoOptions() {
-        OptionValues o = new OptionValues(EconomicMap.create());
-        return createAssembler(o);
-    }
-
     protected void resetForEmittingCode(CompilationResultBuilder crb) {
         crb.resetForEmittingCode();
     }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/graal/code/SubstrateBackendWithAssembler.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core.graal.code;
+
+import org.graalvm.collections.EconomicMap;
+
+import jdk.graal.compiler.asm.Assembler;
+import jdk.graal.compiler.options.OptionValues;
+import jdk.graal.compiler.phases.util.Providers;
+
+public abstract class SubstrateBackendWithAssembler<A extends Assembler<?>> extends SubstrateBackend {
+
+    protected SubstrateBackendWithAssembler(Providers providers) {
+        super(providers);
+    }
+
+    protected abstract A createAssembler(OptionValues options);
+
+    public final A createAssemblerNoOptions() {
+        OptionValues o = new OptionValues(EconomicMap.create());
+        return createAssembler(o);
+    }
+}

substratevm/src/com.oracle.svm.hosted.foreign/src/com/oracle/svm/hosted/foreign/ForeignFunctionsFeature.java

@@ -89,6 +89,8 @@
 import com.oracle.svm.core.foreign.Target_java_nio_MappedMemoryUtils;
 import com.oracle.svm.core.foreign.phases.SubstrateOptimizeSharedArenaAccessPhase;
 import com.oracle.svm.core.graal.RuntimeCompilation;
+import com.oracle.svm.core.graal.code.SubstrateBackend;
+import com.oracle.svm.core.graal.code.SubstrateBackendWithAssembler;
 import com.oracle.svm.core.graal.meta.SubstrateForeignCallsProvider;
 import com.oracle.svm.core.jdk.VectorAPIEnabled;
 import com.oracle.svm.core.meta.MethodPointer;
@@ -405,6 +407,17 @@ public void duringSetup(DuringSetupAccess a) {
         ConfigurationParserUtils.parseAndRegisterConfigurationsFromCombinedFile(getConfigurationParser(imageClassLoader), imageClassLoader, "panama foreign");
     }
 
+    @Override
+    public void beforeCompilation(BeforeCompilationAccess access) {
+        FeatureImpl.BeforeCompilationAccessImpl a = (FeatureImpl.BeforeCompilationAccessImpl) access;
+        SubstrateBackend b = a.getRuntimeConfiguration().getBackendForNormalMethod();
+        if (b instanceof SubstrateBackendWithAssembler<?> bAsm) {
+            foreignFunctionsRuntime.generateTrampolineTemplate(bAsm);
+        } else {
+            throw VMError.shouldNotReachHere("Support for the Foreign Function and Memory API needs a backend with an assembler, it is not available with backend %s", b.getClass());
+        }
+    }
+
     private ConfigurationParser getConfigurationParser(ImageClassLoader imageClassLoader) {
         /*
          * If foreign function calls are not supported on this platform, we still want to parse the

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/pltgot/amd64/AMD64PLTStubGenerator.java

@@ -114,7 +114,7 @@ public byte[] generatePLT(SharedMethod[] got, SubstrateBackend substrateBackend)
         RegisterConfig registerConfig = amd64Backend.getCodeCache().getRegisterConfig();
         Register register = configuration.getGOTPassingRegister(registerConfig);
 
-        AMD64MacroAssembler asm = (AMD64MacroAssembler) amd64Backend.createAssemblerNoOptions();
+        AMD64MacroAssembler asm = amd64Backend.createAssemblerNoOptions();
         PLTSectionSupport support = HostedPLTGOTConfiguration.singleton().getPLTSectionSupport();
 
         asm.setCodePatchingAnnotationConsumer(this::recordResolverCallForPatching);