From 6e416c11d7d5042a92fbb38f2f50b64b202ca084 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Mon, 18 Mar 2024 16:21:12 +0100
Subject: [PATCH] Reduce memory consumption in dependency analyzer

---
 .../teavm/dependency/SuperClassFilter.java    | 45 +++++++++++++++----
 .../teavm/dependency/VirtualCallConsumer.java | 34 ++++++++++++--
 2 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/core/src/main/java/org/teavm/dependency/SuperClassFilter.java b/core/src/main/java/org/teavm/dependency/SuperClassFilter.java
index 11917393e..280d83b02 100644
--- a/core/src/main/java/org/teavm/dependency/SuperClassFilter.java
+++ b/core/src/main/java/org/teavm/dependency/SuperClassFilter.java
@@ -15,13 +15,16 @@
  */
 package org.teavm.dependency;
 
+import com.carrotsearch.hppc.IntIntHashMap;
 import java.util.BitSet;
 import org.teavm.common.OptionalPredicate;
 
 class SuperClassFilter implements DependencyTypeFilter {
+    private static final int SMALL_CACHE_THRESHOLD = 16;
     private OptionalPredicate<String> predicate;
-    private BitSet knownTypes = new BitSet();
-    private BitSet cache = new BitSet();
+    private IntIntHashMap smallCache;
+    private BitSet knownTypes;
+    private BitSet cache;
 
     SuperClassFilter(DependencyAnalyzer dependencyAnalyzer, DependencyType superType) {
         predicate = dependencyAnalyzer.getClassHierarchy().getSuperclassPredicate(superType.getName());
@@ -29,12 +32,38 @@ class SuperClassFilter implements DependencyTypeFilter {
 
     @Override
     public boolean match(DependencyType type) {
-        if (knownTypes.get(type.index)) {
-            return cache.get(type.index);
+        if (knownTypes != null) {
+            if (knownTypes.get(type.index)) {
+                return cache.get(type.index);
+            }
+            boolean result = predicate.test(type.getName(), false);
+            knownTypes.set(type.index);
+            cache.set(type.index, result);
+            return result;
         }
-        boolean result = predicate.test(type.getName(), false);
-        knownTypes.set(type.index);
-        cache.set(type.index, result);
-        return result;
+
+        if (smallCache == null) {
+            smallCache = new IntIntHashMap();
+        }
+
+        var result = smallCache.getOrDefault(type.index, -1);
+        if (result != -1) {
+            return result != 0;
+        }
+
+        var value = predicate.test(type.getName(), false);
+        smallCache.put(type.index, value ? 1 : 0);
+        if (smallCache.size() > SMALL_CACHE_THRESHOLD) {
+            knownTypes = new BitSet();
+            cache = new BitSet();
+            for (var entry : smallCache) {
+                knownTypes.set(entry.key);
+                if (entry.value != 0) {
+                    cache.set(entry.key);
+                }
+            }
+            smallCache = null;
+        }
+        return value;
     }
 }
diff --git a/core/src/main/java/org/teavm/dependency/VirtualCallConsumer.java b/core/src/main/java/org/teavm/dependency/VirtualCallConsumer.java
index 6b3b2ec7f..7b7f454c8 100644
--- a/core/src/main/java/org/teavm/dependency/VirtualCallConsumer.java
+++ b/core/src/main/java/org/teavm/dependency/VirtualCallConsumer.java
@@ -15,17 +15,21 @@
  */
 package org.teavm.dependency;
 
+import com.carrotsearch.hppc.IntHashSet;
+import com.carrotsearch.hppc.IntSet;
 import java.util.BitSet;
 import org.teavm.model.CallLocation;
 import org.teavm.model.MethodDescriptor;
 
 class VirtualCallConsumer implements DependencyConsumer {
+    private static int SMALL_TYPES_THRESHOLD = 16;
     private final MethodDescriptor methodDesc;
     private final DependencyAnalyzer analyzer;
     private final DependencyNode[] parameters;
     private final DependencyNode result;
     private final CallLocation location;
-    private final BitSet knownTypes = new BitSet();
+    private IntSet smallKnownTypes;
+    private BitSet knownTypes;
     private DependencyGraphBuilder.ExceptionConsumer exceptionConsumer;
     private DependencyTypeFilter filter;
     private boolean isPolymorphic;
@@ -43,16 +47,40 @@ class VirtualCallConsumer implements DependencyConsumer {
         this.exceptionConsumer = exceptionConsumer;
     }
 
+    private boolean addKnownType(int index) {
+        if (knownTypes != null) {
+            if (knownTypes.get(index)) {
+                return false;
+            } else {
+                knownTypes.set(index);
+                return true;
+            }
+        }
+        if (smallKnownTypes == null) {
+            smallKnownTypes = new IntHashSet();
+        }
+        if (smallKnownTypes.add(index)) {
+            if (smallKnownTypes.size() > SMALL_TYPES_THRESHOLD) {
+                knownTypes = new BitSet();
+                for (var cursor : smallKnownTypes) {
+                    knownTypes.set(cursor.value);
+                }
+                smallKnownTypes = null;
+            }
+            return true;
+        }
+        return false;
+    }
+
     @Override
     public void consume(DependencyType type) {
         if (!filter.match(type)) {
             return;
         }
 
-        if (knownTypes.get(type.index)) {
+        if (!addKnownType(type.index)) {
             return;
         }
-        knownTypes.set(type.index);
 
         String className = type.getName();