src/java.base/share/classes/jdk/internal/jimage/BasicImageReader.java

rev 16767 : 8175561: Memory churn in jimage code affects startup after resource encapsulation changes
Reviewed-by: jlaskey
rev 16768 : imported patch imgstr_oneup

@@ -247,15 +247,35 @@
 
     public ImageStringsReader getStrings() {
         return stringsReader;
     }
 
-    public ImageLocation findLocation(String mn, String rn) {
-        Objects.requireNonNull(mn);
-        Objects.requireNonNull(rn);
+    public synchronized ImageLocation findLocation(String module, String name) {
+        Objects.requireNonNull(module);
+        Objects.requireNonNull(name);
+        // Details of the algorithm used here can be found in
+        // jdk.tools.jlink.internal.PerfectHashBuilder.
+        int count = header.getTableLength();
+        int index = redirect.get(ImageStringsReader.hashCode(module, name) % count);
+
+        if (index < 0) {
+            // index is twos complement of location attributes index.
+            index = -index - 1;
+        } else if (index > 0) {
+            // index is hash seed needed to compute location attributes index.
+            index = ImageStringsReader.hashCode(module, name, index) % count;
+        } else {
+            // No entry.
+            return null;
+        }
+
+        long[] attributes = getAttributes(offsets.get(index));
 
-        return findLocation("/" + mn + "/" + rn);
+        if (!ImageLocation.verify(module, name, attributes, stringsReader)) {
+            return null;
+        }
+        return new ImageLocation(attributes, stringsReader);
     }
 
     public synchronized ImageLocation findLocation(String name) {
         Objects.requireNonNull(name);
         // Details of the algorithm used here can be found in