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8263452: Javac slow compilation due to algorithmic complexity

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Reviewed-by: vromero, jfranck
This commit is contained in:
Jan Lahoda 2021-05-11 10:06:04 +00:00
parent 67cb22af58
commit 8468001f88
4 changed files with 107 additions and 6 deletions
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8
src/jdk.compiler/share/classes/com/sun/tools/javac/code/Flags.java
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@ -176,7 +176,12 @@ public class Flags {
/** Flag for synthesized default constructors of anonymous classes.
*/
public static final int ANONCONSTR = 1<<29;
public static final int ANONCONSTR = 1<<29; //non-class members
/**
* Flag to indicate the super classes of this ClassSymbol has been attributed.
*/
public static final int SUPER_OWNER_ATTRIBUTED = 1<<29; //ClassSymbols
/** Flag for class symbols to indicate it has been checked and found
* acyclic.
@ -380,6 +385,7 @@ public class Flags {
*/
public static final long NON_SEALED = 1L<<63; // ClassSymbols
/** Modifier masks.
*/
public static final int

5
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
View File

@ -5098,7 +5098,8 @@ public class Attr extends JCTree.Visitor {
chk.checkNonCyclic(null, c.type);
Type st = types.supertype(c.type);
if ((c.flags_field & Flags.COMPOUND) == 0) {
if ((c.flags_field & Flags.COMPOUND) == 0 &&
(c.flags_field & Flags.SUPER_OWNER_ATTRIBUTED) == 0) {
// First, attribute superclass.
if (st.hasTag(CLASS))
attribClass((ClassSymbol)st.tsym);
@ -5106,6 +5107,8 @@ public class Attr extends JCTree.Visitor {
// Next attribute owner, if it is a class.
if (c.owner.kind == TYP && c.owner.type.hasTag(CLASS))
attribClass((ClassSymbol)c.owner);
c.flags_field |= Flags.SUPER_OWNER_ATTRIBUTED;
}
// The previous operations might have attributed the current class

8
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java
View File

@ -2247,7 +2247,7 @@ public class Check {
class CycleChecker extends TreeScanner {
List<Symbol> seenClasses = List.nil();
Set<Symbol> seenClasses = new HashSet<>();
boolean errorFound = false;
boolean partialCheck = false;
@ -2266,7 +2266,7 @@ public class Check {
} else if (sym.kind == TYP) {
checkClass(pos, sym, List.nil());
}
} else {
} else if (sym == null || sym.kind != PCK) {
//not completed yet
partialCheck = true;
}
@ -2315,7 +2315,7 @@ public class Check {
noteCyclic(pos, (ClassSymbol)c);
} else if (!c.type.isErroneous()) {
try {
seenClasses = seenClasses.prepend(c);
seenClasses.add(c);
if (c.type.hasTag(CLASS)) {
if (supertypes.nonEmpty()) {
scan(supertypes);
@ -2338,7 +2338,7 @@ public class Check {
}
}
} finally {
seenClasses = seenClasses.tail;
seenClasses.remove(c);
}
}
}

92
test/langtools/tools/javac/perf/SuperClassAndNesting.java Normal file
View File

@ -0,0 +1,92 @@
/*
* Copyright (c) 2021, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8263452
* @summary Verify javac does not need a long time to process sources with deep class nesting
* and deep inheritance hierarchies.
* @modules jdk.compiler
*/
import java.util.Arrays;
import javax.tools.JavaCompiler;
import javax.tools.ToolProvider;
import com.sun.source.util.JavacTask;
import java.io.IOException;
import java.net.URI;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
public class SuperClassAndNesting {
private static final int SIZE = 100;
public static void main(String... args) throws IOException {
new SuperClassAndNesting().run();
}
void run() throws IOException {
compileTestClass(generateTestClass(SIZE));
}
String generateTestClass(int depth) {
StringBuilder clazz = new StringBuilder();
clazz.append("""
class Test {
class T0 extends java.util.ArrayList {
""");
for (int i = 1; i < depth; i++) {
clazz.append("class T" + i + " extends T" + (i - 1) + " {\n");
}
for (int i = 0; i < depth; i++) {
clazz.append("}\n");
}
clazz.append("}\n");
return clazz.toString();
}
void compileTestClass(String code) throws IOException {
final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
assert tool != null;
JavacTask ct = (JavacTask) tool.getTask(null, null, null,
null, null, Arrays.asList(new MyFileObject(code)));
ct.analyze();
}
static class MyFileObject extends SimpleJavaFileObject {
private final String text;
public MyFileObject(String text) {
super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
this.text = text;
}
@Override
public CharSequence getCharContent(boolean ignoreEncodingErrors) {
return text;
}
}
}