RFR: 8171400: Move checking of duplicate packages in the boot layer to link time
Claes Redestad
claes.redestad at oracle.com
Mon Dec 19 12:30:58 UTC 2016
Hi,
this patch adds a check to see if there are any split packages in the system
modules at link time, and uses this information to enable us to safely skip
a runtime check during bootstrap for the common case that there are none
of the sort.
Webrev[1]: http://cr.openjdk.java.net/~redestad/8171400/webrev.01/
Bug: https://bugs.openjdk.java.net/browse/JDK-8171400
This removes a chunk of the module system bootstrap overhead, and also
amends a small issue where PACKAGES_IN_BOOT_LAYER would be wrong in the
presence of split packages.
Thanks!
/Claes
[1] Since cr.openjdk.java.net is down I've also attached the raw patch.
-------------- next part --------------
# HG changeset patch
# User redestad
# Date 1482149824 -3600
# Mon Dec 19 13:17:04 2016 +0100
# Node ID 0fd05985c26f78eba4ec8614f966d220b1f79ff0
# Parent ab164f8b856977122f61e9d2f0ce8272307f01b4
8171400: Move checking of duplicate packages in the boot layer to link time
Reviewed-by: alanb
diff --git a/src/java.base/share/classes/java/lang/reflect/Layer.java b/src/java.base/share/classes/java/lang/reflect/Layer.java
--- a/src/java.base/share/classes/java/lang/reflect/Layer.java
+++ b/src/java.base/share/classes/java/lang/reflect/Layer.java
@@ -602,12 +602,8 @@
checkGetClassLoaderPermission();
- // For now, no two modules in the boot Layer may contain the same
- // package so we use a simple check for the boot Layer to keep
- // the overhead at startup to a minimum
- if (boot() == null) {
- checkBootModulesForDuplicatePkgs(cf);
- } else {
+ // The boot layer is checked during module system initialization
+ if (boot() != null) {
checkForDuplicatePkgs(cf, clf);
}
@@ -657,27 +653,6 @@
}
/**
- * Checks a configuration for the boot Layer to ensure that no two modules
- * have the same package.
- *
- * @throws LayerInstantiationException
- */
- private static void checkBootModulesForDuplicatePkgs(Configuration cf) {
- Map<String, String> packageToModule = new HashMap<>();
- for (ResolvedModule resolvedModule : cf.modules()) {
- ModuleDescriptor descriptor = resolvedModule.reference().descriptor();
- String name = descriptor.name();
- for (String p : descriptor.packages()) {
- String other = packageToModule.putIfAbsent(p, name);
- if (other != null) {
- throw fail("Package " + p + " in both module "
- + name + " and module " + other);
- }
- }
- }
- }
-
- /**
* Checks a configuration and the module-to-loader mapping to ensure that
* no two modules mapped to the same class loader have the same package.
* It also checks that no two automatic modules have the same package.
diff --git a/src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java b/src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java
--- a/src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java
+++ b/src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java
@@ -308,6 +308,23 @@
}
}
+ // if needed check that there are no split packages in the set of
+ // resolved modules for the boot layer
+ if (SystemModules.hasSplitPackages() || needPostResolutionChecks) {
+ Map<String, String> packageToModule = new HashMap<>();
+ for (ResolvedModule resolvedModule : cf.modules()) {
+ ModuleDescriptor descriptor =
+ resolvedModule.reference().descriptor();
+ String name = descriptor.name();
+ for (String p : descriptor.packages()) {
+ String other = packageToModule.putIfAbsent(p, name);
+ if (other != null) {
+ fail("Package " + p + " in both module "
+ + name + " and module " + other);
+ }
+ }
+ }
+ }
long t4 = System.nanoTime();
diff --git a/src/java.base/share/classes/jdk/internal/module/SystemModules.java b/src/java.base/share/classes/jdk/internal/module/SystemModules.java
--- a/src/java.base/share/classes/jdk/internal/module/SystemModules.java
+++ b/src/java.base/share/classes/jdk/internal/module/SystemModules.java
@@ -57,6 +57,14 @@
public static int PACKAGES_IN_BOOT_LAYER = 1024;
/**
+ * If there are no split packages in the run-time image, we can skip some
+ * checks during bootstrap.
+ */
+ public static boolean hasSplitPackages() {
+ return true;
+ }
+
+ /**
* Returns a non-empty array of ModuleDescriptors in the run-time image.
*
* When running an exploded image it returns an empty array.
diff --git a/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java b/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java
--- a/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java
+++ b/src/jdk.jlink/share/classes/jdk/tools/jlink/internal/plugins/SystemModulesPlugin.java
@@ -34,6 +34,7 @@
import java.util.Collection;
import java.util.EnumSet;
import java.util.HashMap;
+import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
@@ -342,7 +343,8 @@
*
* static Map<String, ModuleDescriptor> map = new HashMap<>();
*/
- private void clinit(int numModules, int numPackages) {
+ private void clinit(int numModules, int numPackages,
+ boolean hasSplitPackages) {
cw.visit(Opcodes.V1_8, ACC_PUBLIC+ACC_FINAL+ACC_SUPER, CLASSNAME,
null, "java/lang/Object", null);
@@ -379,6 +381,17 @@
clinit.visitInsn(RETURN);
clinit.visitMaxs(0, 0);
clinit.visitEnd();
+
+ // public static boolean hasSplitPackages();
+ MethodVisitor split =
+ cw.visitMethod(ACC_PUBLIC+ACC_STATIC, "hasSplitPackages",
+ "()Z", null, null);
+ split.visitCode();
+ split.visitInsn(hasSplitPackages ? ICONST_1 : ICONST_0);
+ split.visitInsn(IRETURN);
+ split.visitMaxs(0, 0);
+ split.visitEnd();
+
}
/*
@@ -416,12 +429,16 @@
*/
public ClassWriter getClassWriter() {
int numModules = moduleInfos.size();
- int numPackages = 0;
+ Set<String> allPackages = new HashSet<>();
+ int packageCount = 0;
for (ModuleInfo minfo : moduleInfos) {
- numPackages += minfo.packages.size();
+ allPackages.addAll(minfo.packages);
+ packageCount += minfo.packages.size();
}
- clinit(numModules, numPackages);
+ int numPackages = allPackages.size();
+ boolean hasSplitPackages = (numPackages < packageCount);
+ clinit(numModules, numPackages, hasSplitPackages);
// generate SystemModules::descriptors
genDescriptorsMethod();
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