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8186092: Unnecessary loader constraints produced when there are multiple defaults

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Do not check loader constraints for overpass methods

Reviewed-by: dholmes, acorn
This commit is contained in:
Harold Seigel 2017-09-28 13:01:24 -04:00
parent 394e6a8318
commit 87e30fd801
18 changed files with 666 additions and 43 deletions
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16
src/hotspot/share/classfile/defaultMethods.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -767,15 +767,14 @@ static void create_default_methods( InstanceKlass* klass,
// This is the guts of the default methods implementation. This is called just
// after the classfile has been parsed if some ancestor has default methods.
//
// First if finds any name/signature slots that need any implementation (either
// First it finds any name/signature slots that need any implementation (either
// because they are miranda or a superclass's implementation is an overpass
// itself). For each slot, iterate over the hierarchy, to see if they contain a
// signature that matches the slot we are looking at.
//
// For each slot filled, we generate an overpass method that either calls the
// unique default method candidate using invokespecial, or throws an exception
// (in the case of no default method candidates, or more than one valid
// candidate). These methods are then added to the class's method list.
// For each slot filled, we either record the default method candidate in the
// klass default_methods list or, only to handle exception cases, we create an
// overpass method that throws an exception and add it to the klass methods list.
// The JVM does not create bridges nor handle generic signatures here.
void DefaultMethods::generate_default_methods(
InstanceKlass* klass, const GrowableArray<Method*>* mirandas, TRAPS) {
@ -901,6 +900,11 @@ static void switchover_constant_pool(BytecodeConstantPool* bpool,
// This allows virtual methods to override the overpass, but ensures
// that a local method search will find the exception rather than an abstract
// or default method that is not a valid candidate.
//
// Note that if overpass method are ever created that are not exception
// throwing methods then the loader constraint checking logic for vtable and
// itable creation needs to be changed to check loader constraints for the
// overpass methods that do not throw exceptions.
static void create_defaults_and_exceptions(
GrowableArray<EmptyVtableSlot*>* slots,
InstanceKlass* klass, TRAPS) {