--- a/jvmci/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotMemoryAccessProviderImpl.java	Fri Apr 01 10:32:24 2016 -0700
+++ b/jvmci/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotMemoryAccessProviderImpl.java	Wed Mar 30 16:06:48 2016 +0200
@@ -23,7 +23,6 @@
 package jdk.vm.ci.hotspot;
 
 import static jdk.vm.ci.hotspot.UnsafeAccess.UNSAFE;
-import jdk.vm.ci.common.JVMCIError;
 import jdk.vm.ci.hotspot.HotSpotVMConfig.CompressEncoding;
 import jdk.vm.ci.meta.Constant;
 import jdk.vm.ci.meta.JavaConstant;
@@ -62,7 +61,7 @@
                     return ((HotSpotResolvedObjectTypeImpl) metaspaceObject).mirror().isArray();
                 }
             } else {
-                throw new JVMCIError("%s", metaspaceObject);
+                throw new IllegalArgumentException(String.valueOf(metaspaceObject));
             }
         }
         return false;
@@ -78,7 +77,7 @@
                 return prim.asLong();
             }
         }
-        throw new JVMCIError("%s", base);
+        throw new IllegalArgumentException(String.valueOf(base));
     }
 
     private static long readRawValue(Constant baseConstant, long displacement, int bits) {
@@ -94,7 +93,7 @@
                 case Long.SIZE:
                     return UNSAFE.getLong(base, displacement);
                 default:
-                    throw new JVMCIError("%d", bits);
+                    throw new IllegalArgumentException(String.valueOf(bits));
             }
         } else {
             long pointer = asRawPointer(baseConstant);
@@ -108,7 +107,7 @@
                 case Long.SIZE:
                     return UNSAFE.getLong(pointer + displacement);
                 default:
-                    throw new JVMCIError("%d", bits);
+                    throw new IllegalArgumentException(String.valueOf(bits));
             }
         }
     }
@@ -183,7 +182,7 @@
                 case Double:
                     return JavaConstant.forDouble(Double.longBitsToDouble(rawValue));
                 default:
-                    throw new JVMCIError("Unsupported kind: %s", kind);
+                    throw new IllegalArgumentException("Unsupported kind: " + kind);
             }
         } catch (NullPointerException e) {
             return null;

--- a/jvmci/jdk.vm.ci.meta/src/jdk/vm/ci/meta/MemoryAccessProvider.java	Fri Apr 01 10:32:24 2016 -0700
+++ b/jvmci/jdk.vm.ci.meta/src/jdk/vm/ci/meta/MemoryAccessProvider.java	Wed Mar 30 16:06:48 2016 +0200
@@ -35,8 +35,10 @@
      * @param displacement the displacement within the object in bytes
      * @return the read value encapsulated in a {@link JavaConstant} object, or {@code null} if the
      *         value cannot be read.
+     * @throws IllegalArgumentException if {@code kind} is {@link JavaKind#Void} or not
+     *             {@linkplain JavaKind#isPrimitive() primitive} kind
      */
-    JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant base, long displacement);
+    JavaConstant readUnsafeConstant(JavaKind kind, JavaConstant base, long displacement) throws IllegalArgumentException;
 
     /**
      * Reads a primitive value using a base address and a displacement.
@@ -46,8 +48,11 @@
      * @param displacement the displacement within the object in bytes
      * @param bits the number of bits to read from memory
      * @return the read value encapsulated in a {@link JavaConstant} object of {@link JavaKind} kind
+     * @throws IllegalArgumentException if {@code kind} is {@link JavaKind#Void} or not
+     *             {@linkplain JavaKind#isPrimitive() primitive} kind or {@code bits} is not 8, 16,
+     *             32 or 64
      */
-    JavaConstant readPrimitiveConstant(JavaKind kind, Constant base, long displacement, int bits);
+    JavaConstant readPrimitiveConstant(JavaKind kind, Constant base, long displacement, int bits) throws IllegalArgumentException;
 
     /**
      * Reads a Java {@link Object} value using a base address and a displacement.