ArC build time perf improvement

This removes the need to iterate over all beans when performing
resolution. For a project with 2k injection points this saves close to
0.5s on my desktop.

independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanDeployment.java

@@ -68,6 +68,7 @@ public class BeanDeployment {
     private final Map<DotName, StereotypeInfo> stereotypes;
 
     private final List<BeanInfo> beans;
+    private volatile Map<Type, List<BeanInfo>> beansByType = null;
 
     private final List<InterceptorInfo> interceptors;
     private final List<DecoratorInfo> decorators;
@@ -231,6 +232,7 @@ BeanRegistrar.RegistrationContext registerBeans(List<BeanRegistrar> beanRegistra
         List<InjectionPointInfo> injectionPoints = new ArrayList<>();
         this.beans.addAll(findBeans(initBeanDefiningAnnotations(beanDefiningAnnotations, stereotypes.keySet()), observers,
                 injectionPoints, jtaCapabilities));
+        beansByType = null;
         // Note that we need to use view of the collections to reflect further additions, e.g. synthetic beans and observers
         buildContextPut(Key.BEANS.asString(), Collections.unmodifiableList(beans));
         buildContextPut(Key.OBSERVERS.asString(), Collections.unmodifiableList(observers));
@@ -375,6 +377,7 @@ private Set<BeanInfo> removeUnusedBeans(Set<BeanInfo> declaresObserver, List<Pre
                 allUnusedExclusions);
         if (!removableBeans.isEmpty()) {
             this.beans.removeAll(removableBeans);
+            beansByType = null;
             this.removedBeans.addAll(removableBeans);
             List<InjectionPointInfo> removableInjectionPoints = removableBeans.stream()
                     .flatMap(d -> d.getAllInjectionPoints().stream()).collect(Collectors.toList());
@@ -407,6 +410,29 @@ public Collection<BeanInfo> getBeans() {
         return Collections.unmodifiableList(beans);
     }
 
+    public Collection<BeanInfo> getBeansByType(Type type) {
+        Map<Type, List<BeanInfo>> byType = beansByType;
+        if (byType == null) {
+            synchronized (this) {
+                byType = beansByType;
+                if (byType == null) {
+                    byType = new HashMap<>();
+                    for (var i : beans) {
+                        for (var t : i.types) {
+                            byType.computeIfAbsent(t, (s) -> new ArrayList<>()).add(i);
+                        }
+                    }
+                    this.beansByType = byType;
+                }
+            }
+        }
+        var ret = byType.get(type);
+        if (ret == null) {
+            return Collections.emptyList();
+        }
+        return Collections.unmodifiableList(ret);
+    }
+
     public Collection<BeanInfo> getRemovedBeans() {
         return Collections.unmodifiableSet(removedBeans);
     }
@@ -1126,6 +1152,7 @@ private void addSyntheticBean(BeanInfo bean) {
             }
         }
         beans.add(bean);
+        beansByType = null;
     }
 
     private void addSyntheticObserver(ObserverConfigurator configurator) {

independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanResolverImpl.java

@@ -9,6 +9,7 @@
 
 import io.quarkus.arc.processor.InjectionPointInfo.TypeAndQualifiers;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
@@ -81,7 +82,11 @@ List<BeanInfo> resolve(TypeAndQualifiers typeAndQualifiers) {
 
     private List<BeanInfo> findMatching(TypeAndQualifiers typeAndQualifiers) {
         List<BeanInfo> resolved = new ArrayList<>();
-        for (BeanInfo b : beanDeployment.getBeans()) {
+        //optimisation for the simple class case
+        Collection<BeanInfo> potentialBeans = typeAndQualifiers.type.kind() == CLASS
+                ? beanDeployment.getBeansByType(typeAndQualifiers.type)
+                : beanDeployment.getBeans();
+        for (BeanInfo b : potentialBeans) {
             if (Beans.matches(b, typeAndQualifiers)) {
                 resolved.add(b);
             }
@@ -91,7 +96,10 @@ private List<BeanInfo> findMatching(TypeAndQualifiers typeAndQualifiers) {
 
     List<BeanInfo> findTypeMatching(Type type) {
         List<BeanInfo> resolved = new ArrayList<>();
-        for (BeanInfo b : beanDeployment.getBeans()) {
+        //optimisation for the simple class case
+        Collection<BeanInfo> potentialBeans = type.kind() == CLASS ? beanDeployment.getBeansByType(type)
+                : beanDeployment.getBeans();
+        for (BeanInfo b : potentialBeans) {
             if (Beans.matchesType(b, type)) {
                 resolved.add(b);
             }