Do not force loading all kt-files inside LazyPackageDescriptor constructor

Effectively it leads to all stubs being built for any once used package

The idea is that they only were used for FILE_TO_PACKAGE_FRAGMENT
that is mostly read in backend and rarely in the IDE, so we can replace
its usages with searching through related package-fragments

compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingContext.java

@@ -262,7 +262,6 @@ public interface BindingContext {
     WritableSlice<ClassDescriptor, FunctionDescriptor> DATA_CLASS_COPY_FUNCTION = Slices.createSimpleSlice();
 
     WritableSlice<FqNameUnsafe, ClassDescriptor> FQNAME_TO_CLASS_DESCRIPTOR = new BasicWritableSlice<>(DO_NOTHING, true);
-    WritableSlice<KtFile, PackageFragmentDescriptor> FILE_TO_PACKAGE_FRAGMENT = Slices.createSimpleSlice();
     WritableSlice<FqName, Collection<KtFile>> PACKAGE_TO_FILES = Slices.createSimpleSlice();
     WritableSlice<KtBinaryExpressionWithTypeRHS, Boolean> CAST_TYPE_USED_AS_EXPECTED_TYPE = Slices.createSimpleSlice();
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/declarations/CombinedPackageMemberDeclarationProvider.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.resolve.lazy.declarations
 
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtDestructuringDeclarationEntry
+import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 
 class CombinedPackageMemberDeclarationProvider(
@@ -27,6 +28,8 @@ class CombinedPackageMemberDeclarationProvider(
 
     override fun getPackageFiles() = providers.flatMap { it.getPackageFiles() }
 
+    override fun containsFile(file: KtFile) = providers.any { it.containsFile(file) }
+
     override fun getDeclarations(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean)
             = providers.flatMap { it.getDeclarations(kindFilter, nameFilter) }
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/declarations/FileBasedPackageMemberDeclarationProvider.kt

@@ -16,9 +16,9 @@
 
 package org.jetbrains.kotlin.resolve.lazy.declarations
 
-import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.storage.StorageManager
 
 class FileBasedPackageMemberDeclarationProvider(
@@ -45,6 +45,8 @@ class FileBasedPackageMemberDeclarationProvider(
 
     override fun getPackageFiles() = packageFiles
 
+    override fun containsFile(file: KtFile) = file in packageFiles
+
     override fun toString() = "Declarations for package $fqName with files ${packageFiles.map { it.name }} " +
                               "with declarations inside ${packageFiles.flatMap { it.declarations }.map { it.name ?: "???"}}"
 }

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/declarations/PackageMemberDeclarationProvider.kt

@@ -16,13 +16,14 @@
 
 package org.jetbrains.kotlin.resolve.lazy.declarations
 
-import org.jetbrains.annotations.ReadOnly
-import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.psi.KtFile
 
 interface PackageMemberDeclarationProvider : DeclarationProvider {
     fun getAllDeclaredSubPackages(nameFilter: (Name) -> Boolean): Collection<FqName>
 
     fun getPackageFiles(): Collection<KtFile>
+
+    fun containsFile(file: KtFile): Boolean
 }

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyPackageDescriptor.java

@@ -20,8 +20,6 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor;
 import org.jetbrains.kotlin.descriptors.impl.PackageFragmentDescriptorImpl;
 import org.jetbrains.kotlin.name.FqName;
-import org.jetbrains.kotlin.psi.KtFile;
-import org.jetbrains.kotlin.resolve.BindingContext;
 import org.jetbrains.kotlin.resolve.lazy.ForceResolveUtil;
 import org.jetbrains.kotlin.resolve.lazy.LazyEntity;
 import org.jetbrains.kotlin.resolve.lazy.ResolveSession;
@@ -42,10 +40,6 @@ public class LazyPackageDescriptor extends PackageFragmentDescriptorImpl impleme
         this.declarationProvider = declarationProvider;
 
         this.memberScope = new LazyPackageMemberScope(resolveSession, declarationProvider, this);
-
-        for (KtFile file : declarationProvider.getPackageFiles()) {
-            resolveSession.getTrace().record(BindingContext.FILE_TO_PACKAGE_FRAGMENT, file, this);
-        }
     }
 
     @NotNull

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/packageDescriptorUtil.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.resolve.lazy.descriptors
+
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.psi.KtFile
+
+fun ModuleDescriptor.findPackageFragmentForFile(ktFile: KtFile): PackageFragmentDescriptor? =
+        getPackage(ktFile.packageFqName).fragments
+                .filterIsInstance<LazyPackageDescriptor>()
+                .firstOrNull { it.declarationProvider.containsFile(ktFile) }