From e48dfb27b0dda2db3874604f5a570d1c80bee336 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Mon, 29 Apr 2024 16:32:16 +0200
Subject: [PATCH] Improve inlining performance by caching method complexity

---
 .../optimization/DefaultInliningStrategy.java | 28 +++++++++++++++----
 .../teavm/model/optimization/Inlining.java    |  1 +
 .../model/optimization/InliningStrategy.java  |  3 ++
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/core/src/main/java/org/teavm/model/optimization/DefaultInliningStrategy.java b/core/src/main/java/org/teavm/model/optimization/DefaultInliningStrategy.java
index b93924f60..d2de45b5b 100644
--- a/core/src/main/java/org/teavm/model/optimization/DefaultInliningStrategy.java
+++ b/core/src/main/java/org/teavm/model/optimization/DefaultInliningStrategy.java
@@ -15,7 +15,9 @@
  */
 package org.teavm.model.optimization;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import org.teavm.model.BasicBlockReader;
 import org.teavm.model.MethodReference;
 import org.teavm.model.ProgramReader;
@@ -32,6 +34,7 @@ public class DefaultInliningStrategy implements InliningStrategy {
     private final int totalComplexityThreshold;
     private final boolean onceUsedOnly;
     private int getComplexityDepth;
+    private Map<MethodReference, Complexity> complexityCache = new HashMap<>();
 
     public DefaultInliningStrategy(int complexityThreshold, int depthThreshold, int totalComplexityThreshold,
             boolean onceUsedOnly) {
@@ -53,6 +56,20 @@ public class DefaultInliningStrategy implements InliningStrategy {
         return new InliningStepImpl(complexityHolder);
     }
 
+    @Override
+    public void methodChanged(MethodReference method) {
+        complexityCache.remove(method);
+    }
+
+    private Complexity getComplexity(MethodReference methodRef, InliningContext context) {
+        var result = complexityCache.get(methodRef);
+        if (result == null) {
+            result = getComplexity(context.getProgram(methodRef), context);
+            complexityCache.put(methodRef, result);
+        }
+        return result;
+    }
+
     private Complexity getComplexity(ProgramReader program, InliningContext context) {
         int complexity = 0;
         ComplexityCounter counter = new ComplexityCounter(context);
@@ -81,7 +98,7 @@ public class DefaultInliningStrategy implements InliningStrategy {
                 return null;
             }
 
-            Complexity complexity = getComplexity(program, context);
+            Complexity complexity = getComplexity(method, context);
             if (onceUsedOnly && !context.isUsedOnce(method)) {
                 if (complexity.callsToUsedOnceMethods || complexity.score > 1) {
                     return null;
@@ -125,19 +142,18 @@ public class DefaultInliningStrategy implements InliningStrategy {
         public void invoke(VariableReader receiver, VariableReader instance, MethodReference method,
                 List<? extends VariableReader> arguments, InvocationType type) {
             if (type == InvocationType.SPECIAL && context != null && context.isUsedOnce(method)) {
-                ProgramReader program = context.getProgram(method);
-                if (!isTrivialCall(program)) {
+                if (!isTrivialCall(method)) {
                     callsToUsedOnceMethods = true;
                 }
             }
         }
 
-        private boolean isTrivialCall(ProgramReader program) {
-            if (program == null || getComplexityDepth > 10) {
+        private boolean isTrivialCall(MethodReference methodRef) {
+            if (context.getProgram(methodRef) == null || getComplexityDepth > 10) {
                return false;
             }
             getComplexityDepth++;
-            Complexity complexity = getComplexity(program, context);
+            Complexity complexity = getComplexity(methodRef, context);
             getComplexityDepth--;
             return complexity.score <= 1 && !complexity.callsToUsedOnceMethods;
         }
diff --git a/core/src/main/java/org/teavm/model/optimization/Inlining.java b/core/src/main/java/org/teavm/model/optimization/Inlining.java
index c360aad73..6f5cd6eb1 100644
--- a/core/src/main/java/org/teavm/model/optimization/Inlining.java
+++ b/core/src/main/java/org/teavm/model/optimization/Inlining.java
@@ -175,6 +175,7 @@ public class Inlining {
         instructionsToSkip = null;
 
         new UnreachableBasicBlockEliminator().optimize(program);
+        strategy.methodChanged(method);
     }
 
     private boolean applyOnce(Program program, MethodReference method) {
diff --git a/core/src/main/java/org/teavm/model/optimization/InliningStrategy.java b/core/src/main/java/org/teavm/model/optimization/InliningStrategy.java
index 93dc18dc0..961272f43 100644
--- a/core/src/main/java/org/teavm/model/optimization/InliningStrategy.java
+++ b/core/src/main/java/org/teavm/model/optimization/InliningStrategy.java
@@ -20,4 +20,7 @@ import org.teavm.model.ProgramReader;
 
 public interface InliningStrategy {
     InliningStep start(MethodReference method, ProgramReader program);
+
+    default void methodChanged(MethodReference method) {
+    }
 }