diff --git a/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/NodeLowerer.java b/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/NodeLowerer.java
index 63a504d24025..118c67af2293 100644
--- a/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/NodeLowerer.java
+++ b/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/NodeLowerer.java
@@ -24,7 +24,7 @@
  */
 package jdk.graal.compiler.hightiercodegen;
 
-import jdk.graal.compiler.debug.GraalError;
+import jdk.graal.compiler.graph.GraalGraphError;
 import jdk.graal.compiler.graph.Node;
 import jdk.graal.compiler.graph.iterators.NodeIterable;
 import jdk.graal.compiler.hightiercodegen.variables.ResolvedVar;
@@ -351,7 +351,7 @@ protected void dispatch(Node node) {
      * ignored.
      */
     protected void handleUnknownNodeType(Node node) {
-        throw GraalError.unimplemented("Could not lower node: " + node);
+        throw new GraalGraphError("No lowerings found for node: %s", node).addContext(node);
     }
 
     protected abstract void lower(BlackholeNode node);
diff --git a/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/irwalk/IRWalker.java b/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/irwalk/IRWalker.java
index ed4c70a81455..eb8092f90be9 100644
--- a/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/irwalk/IRWalker.java
+++ b/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hightiercodegen/irwalk/IRWalker.java
@@ -30,6 +30,7 @@
 import jdk.graal.compiler.core.common.cfg.BlockMap;
 import jdk.graal.compiler.debug.DebugContext;
 import jdk.graal.compiler.debug.DebugContext.Scope;
+import jdk.graal.compiler.debug.GraalError;
 import jdk.graal.compiler.graph.Node;
 import jdk.graal.compiler.graph.NodeMap;
 import jdk.graal.compiler.hightiercodegen.CodeGenTool;
@@ -73,7 +74,7 @@ public void lowerFunction(DebugContext debugContext) {
             lower(debugContext);
             verifier.verify(cfg.graph, codeGenTool, reconstructionData);
         } catch (Throwable t) {
-            throw debugContext.handle(t);
+            throw debugContext.handle(new GraalError(t).addContext("graph", cfg.graph));
         }
     }
 
diff --git a/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageCodeCache.java b/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageCodeCache.java
index c4c090d2caa5..0a70ced15c89 100644
--- a/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageCodeCache.java
+++ b/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageCodeCache.java
@@ -48,8 +48,6 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import com.oracle.svm.core.meta.CompressedNullConstant;
-import com.oracle.svm.core.interpreter.InterpreterSupport;
 import org.graalvm.collections.Pair;
 import org.graalvm.nativeimage.ImageSingletons;
 import org.graalvm.nativeimage.Platform;
@@ -83,6 +81,8 @@
 import com.oracle.svm.core.configure.ConditionalRuntimeValue;
 import com.oracle.svm.core.deopt.DeoptEntryInfopoint;
 import com.oracle.svm.core.graal.code.SubstrateDataBuilder;
+import com.oracle.svm.core.interpreter.InterpreterSupport;
+import com.oracle.svm.core.meta.CompressedNullConstant;
 import com.oracle.svm.core.meta.MethodPointer;
 import com.oracle.svm.core.meta.SubstrateMethodPointerConstant;
 import com.oracle.svm.core.option.HostedOptionKey;
@@ -269,9 +269,13 @@ public Map<Constant, Object> initAndGetEmbeddedConstants() {
         return embeddedConstants;
     }
 
-    public void addConstantsToHeap() {
+    public Map<Constant, Object> getEmbeddedConstants() {
         VMError.guarantee(!embeddedConstants.isEmpty(), "Embedded constants should already be computed.");
-        embeddedConstants.forEach((constant, reason) -> addConstantToHeap(constant, reason instanceof BytecodePosition position ? position.getMethod().getName() : reason));
+        return Collections.unmodifiableMap(embeddedConstants);
+    }
+
+    public void addConstantsToHeap() {
+        getEmbeddedConstants().forEach((constant, reason) -> addConstantToHeap(constant, reason instanceof BytecodePosition position ? position.getMethod().getName() : reason));
     }
 
     private void addConstantToHeap(Constant constant, Object reason) {
diff --git a/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageHeap.java b/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageHeap.java
index 92343ee5f5bb..920997dc83a0 100644
--- a/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageHeap.java
+++ b/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/image/NativeImageHeap.java
@@ -657,7 +657,7 @@ private static HostedType requireType(Optional<HostedType> optionalType, Object
         return hostedType;
     }
 
-    static RuntimeException reportIllegalType(Object object, Object reason) {
+    public static RuntimeException reportIllegalType(Object object, Object reason) {
         throw reportIllegalType(object, reason, "");
     }