ModuleDescriptor: invert "friends" relation

Fixes memory leak caused by modules storing their friends (which can be potentially recreated many times)

compiler/frontend/src/org/jetbrains/kotlin/analyzer/AnalyzerFacade.kt

@@ -169,37 +169,33 @@ abstract class AnalyzerFacade<in P : PlatformAnalysisParameters> {
         fun computeDependencyDescriptors(module: M): List<ModuleDescriptorImpl> {
             val orderedDependencies = firstDependency.singletonOrEmptyList() + module.dependencies()
             val dependenciesDescriptors = orderedDependencies.mapTo(ArrayList<ModuleDescriptorImpl>()) {
-                        dependencyInfo ->
-                        resolverForProject.descriptorForModule(dependencyInfo as M)
-                    }
+                dependencyInfo ->
+                resolverForProject.descriptorForModule(dependencyInfo as M)
+            }
             module.dependencyOnBuiltIns().adjustDependencies(
                     resolverForProject.descriptorForModule(module).builtIns.builtInsModule, dependenciesDescriptors)
             return dependenciesDescriptors
         }
 
+        fun computeModulesWhoseInternalsAreVisible(module: M): Set<ModuleDescriptorImpl> {
+            return module.modulesWhoseInternalsAreVisible().mapTo(LinkedHashSet()) { resolverForProject.descriptorForModule(it as M) }
+        }
+
         fun setupModuleDependencies() {
             modules.forEach {
                 module ->
                 resolverForProject.descriptorForModule(module).setDependencies(
-                        LazyModuleDependencies(storageManager) { computeDependencyDescriptors(module) }
+                        LazyModuleDependencies(
+                                storageManager,
+                                { computeDependencyDescriptors(module) },
+                                { computeModulesWhoseInternalsAreVisible(module) }
+                        )
                 )
             }
         }
 
         setupModuleDependencies()
 
-        fun addFriends() {
-            modules.forEach {
-                module ->
-                val descriptor = resolverForProject.descriptorForModule(module)
-                module.modulesWhoseInternalsAreVisible().forEach {
-                    resolverForProject.descriptorForModule(it as M).addFriend(descriptor)
-                }
-            }
-        }
-
-        addFriends()
-
         fun initializeResolverForProject() {
             modules.forEach {
                 module ->

core/descriptors/src/org/jetbrains/kotlin/descriptors/ModuleDescriptor.kt

@@ -28,7 +28,7 @@ interface ModuleDescriptor : DeclarationDescriptor, ModuleParameters {
 
     val builtIns: KotlinBuiltIns
 
-    fun isFriend(other: ModuleDescriptor): Boolean
+    fun shouldSeeInternalsOf(targetModule: ModuleDescriptor): Boolean
 
     override fun substitute(substitutor: TypeSubstitutor): ModuleDescriptor {
         return this

core/descriptors/src/org/jetbrains/kotlin/descriptors/Visibilities.java

@@ -207,7 +207,7 @@ public class Visibilities {
         @Override
         public boolean isVisible(@Nullable ReceiverValue receiver, @NotNull DeclarationDescriptorWithVisibility what, @NotNull DeclarationDescriptor from) {
             DeclarationDescriptor fromOrModule = from instanceof PackageViewDescriptor ? ((PackageViewDescriptor) from).getModule() : from;
-            if (!DescriptorUtils.getContainingModule(what).isFriend(DescriptorUtils.getContainingModule(fromOrModule))) return false;
+            if (!DescriptorUtils.getContainingModule(fromOrModule).shouldSeeInternalsOf(DescriptorUtils.getContainingModule(what))) return false;
 
             return MODULE_VISIBILITY_HELPER.isInFriendModule(what, from);
         }

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/ModuleDescriptorImpl.kt

@@ -26,7 +26,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.utils.sure
-import java.util.*
+import java.lang.IllegalArgumentException
 
 class ModuleDescriptorImpl @JvmOverloads constructor(
         moduleName: Name,
@@ -56,8 +56,8 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
 
     private val packageFragmentProviderForWholeModuleWithDependencies by lazy {
         val moduleDependencies = dependencies.sure { "Dependencies of module $id were not set before querying module content" }
-        val dependenciesDescriptors = moduleDependencies.descriptors
-        assert(this in dependenciesDescriptors) { "Module ${id} is not contained in his own dependencies, this is probably a misconfiguration" }
+        val dependenciesDescriptors = moduleDependencies.allDependencies
+        assert(this in dependenciesDescriptors) { "Module $id is not contained in his own dependencies, this is probably a misconfiguration" }
         dependenciesDescriptors.forEach {
             dependency ->
             assert(dependency.isInitialized) {
@@ -82,7 +82,11 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
     }
 
     fun setDependencies(descriptors: List<ModuleDescriptorImpl>) {
-        setDependencies(ModuleDependenciesImpl(descriptors))
+        setDependencies(ModuleDependenciesImpl(descriptors, emptySet()))
+    }
+
+    override fun shouldSeeInternalsOf(targetModule: ModuleDescriptor): Boolean {
+        return this == targetModule || targetModule in dependencies!!.modulesWhoseInternalsAreVisible
     }
 
     private val id: String
@@ -99,31 +103,28 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
     val packageFragmentProvider: PackageFragmentProvider
         get() = packageFragmentProviderForWholeModuleWithDependencies
 
-    private val friendModules = LinkedHashSet<ModuleDescriptor>()
-
-    override fun isFriend(other: ModuleDescriptor) = other == this || other in friendModules
-
-    fun addFriend(friend: ModuleDescriptorImpl): Unit {
-        assert(friend != this) { "Attempt to make module $id a friend to itself" }
-        friendModules.add(friend)
-    }
-
     @Suppress("UNCHECKED_CAST")
     override fun <T> getCapability(capability: ModuleDescriptor.Capability<T>) = capabilities[capability] as? T
 }
 
 interface ModuleDependencies {
-    val descriptors: List<ModuleDescriptorImpl>
+    val allDependencies: List<ModuleDescriptorImpl>
+    val modulesWhoseInternalsAreVisible: Set<ModuleDescriptorImpl>
 }
 
-class ModuleDependenciesImpl(override val descriptors: List<ModuleDescriptorImpl>) : ModuleDependencies
+class ModuleDependenciesImpl(
+        override val allDependencies: List<ModuleDescriptorImpl>,
+        override val modulesWhoseInternalsAreVisible: Set<ModuleDescriptorImpl>
+) : ModuleDependencies
 
 class LazyModuleDependencies(
         storageManager: StorageManager,
-        computeDependencies: () -> List<ModuleDescriptorImpl>
+        computeDependencies: () -> List<ModuleDescriptorImpl>,
+        computeModulesWhoseInternalsAreVisible: () -> Set<ModuleDescriptorImpl>
 ) : ModuleDependencies {
     private val dependencies = storageManager.createLazyValue(computeDependencies)
+    private val visibleInternals = storageManager.createLazyValue(computeModulesWhoseInternalsAreVisible)
 
-    override val descriptors: List<ModuleDescriptorImpl>
-        get() = dependencies()
+    override val allDependencies: List<ModuleDescriptorImpl> get() = dependencies()
+    override val modulesWhoseInternalsAreVisible: Set<ModuleDescriptorImpl> get() = visibleInternals()
 }

core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java

@@ -118,7 +118,7 @@ public class ErrorUtils {
             }
 
             @Override
-            public boolean isFriend(@NotNull ModuleDescriptor other) {
+            public boolean shouldSeeInternalsOf(@NotNull ModuleDescriptor targetModule) {
                 return false;
             }