Refactor: Simplify MethodEntry::compareTo by generating signature String

Note: Generating the signatures on demand and not in the constructor
seems beneficial as it results in producing ~10900 signatures for the
~16600 `MethodEntry`s that we generate for the `hello.Hello` example we
use in debuginfo testing.

Author: zakkak

substratevm/src/com.oracle.objectfile/src/com/oracle/objectfile/debugentry/MethodEntry.java

@@ -28,13 +28,17 @@
 
 import com.oracle.objectfile.debuginfo.DebugInfoProvider.DebugRangeInfo;
 
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
 public class MethodEntry extends MemberEntry implements Comparable<MethodEntry> {
     final TypeEntry[] paramTypes;
     final String[] paramNames;
     public final boolean isDeoptTarget;
     boolean isInRange;
 
     final String symbolName;
+    private String signature;
 
     public MethodEntry(FileEntry fileEntry, String symbolName, String methodName, ClassEntry ownerType,
                     TypeEntry valueType, TypeEntry[] paramTypes, String[] paramNames, int modifiers,
@@ -120,6 +124,13 @@ public String getSymbolName() {
         return symbolName;
     }
 
+    private String getSignature() {
+        if (signature == null) {
+            signature = Arrays.stream(paramTypes).map(TypeEntry::getTypeName).collect(Collectors.joining(", "));
+        }
+        return signature;
+    }
+
     public int compareTo(String methodName, String paramSignature, String returnTypeName) {
         int nameComparison = memberName.compareTo(methodName);
         if (nameComparison != 0) {
@@ -129,24 +140,7 @@ public int compareTo(String methodName, String paramSignature, String returnType
         if (typeComparison != 0) {
             return typeComparison;
         }
-        String[] paramTypeNames = paramSignature.split((","));
-        int length;
-        if (paramSignature.trim().length() == 0) {
-            length = 0;
-        } else {
-            length = paramTypeNames.length;
-        }
-        int paramCountComparison = getParamCount() - length;
-        if (paramCountComparison != 0) {
-            return paramCountComparison;
-        }
-        for (int i = 0; i < getParamCount(); i++) {
-            int paraComparison = getParamTypeName(i).compareTo(paramTypeNames[i].trim());
-            if (paraComparison != 0) {
-                return paraComparison;
-            }
-        }
-        return 0;
+        return getSignature().compareTo(paramSignature);
     }
 
     @Override
@@ -160,16 +154,6 @@ public int compareTo(MethodEntry other) {
         if (typeComparison != 0) {
             return typeComparison;
         }
-        int paramCountComparison = getParamCount() - other.getParamCount();
-        if (paramCountComparison != 0) {
-            return paramCountComparison;
-        }
-        for (int i = 0; i < getParamCount(); i++) {
-            int paramComparison = getParamTypeName(i).compareTo(other.getParamTypeName(i));
-            if (paramComparison != 0) {
-                return paramComparison;
-            }
-        }
-        return 0;
+        return getSignature().compareTo(other.getSignature());
     }
 }