src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotNmethod.java
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
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* 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.
*
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package jdk.vm.ci.hotspot;
import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
import static jdk.vm.ci.services.Services.IS_IN_NATIVE_IMAGE;
import jdk.vm.ci.code.InstalledCode;
import jdk.vm.ci.code.InvalidInstalledCodeException;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.JavaType;
import jdk.vm.ci.meta.ResolvedJavaMethod;
/**
* Implementation of {@link InstalledCode} for code installed as an {@code nmethod}. The address of
* the {@code nmethod} is stored in {@link InstalledCode#address} and the value of
* {@code nmethod::verified_entry_point()} is in {@link InstalledCode#entryPoint}.
*/
public class HotSpotNmethod extends HotSpotInstalledCode {
/**
* This (indirect) {@code Method*} reference is safe since class redefinition preserves all
* methods associated with nmethods in the code cache.
*/
private final HotSpotResolvedJavaMethodImpl method;
/**
* Specifies whether the {@code nmethod} associated with this object is the code executed by
* default HotSpot linkage when a normal Java call to {@link #method} is made. That is, does
* {@code this.method.metadataHandle->_code} == {@code this.address}. If not, then the
* {@code nmethod} can only be invoked via a reference to this object. An example of this is the
* trampoline mechanism used by Truffle: https://goo.gl/LX88rZ.
*/
private final boolean isDefault;
/**
* Determines whether this object is in the oops table of the nmethod.
* <p>
* If this object is in the oops table, the VM uses the oops table entry to update this object's
* {@link #address} and {@link #entryPoint} fields when the state of the nmethod changes. The
* nmethod will be unloadable when this object dies.
* <p>
* Otherwise, the nmethod's unloadability is not changed when this object dies.
*/
boolean inOopsTable() {
return compileIdSnapshot != 0;
}
/**
* If this field is 0, this object is in the oops table of the nmethod. Otherwise, the value of
* the field records the nmethod's compile identifier. This value is used to confirm an entry in
* the code cache retrieved by {@link #address} is indeed the nmethod represented by this
* object.
*
* @see #inOopsTable
*/
private final long compileIdSnapshot;
HotSpotNmethod(HotSpotResolvedJavaMethodImpl method, String name, boolean isDefault, long compileId) {
super(name);
this.method = method;
this.isDefault = isDefault;
boolean inOopsTable = !IS_IN_NATIVE_IMAGE && !isDefault;
this.compileIdSnapshot = inOopsTable ? 0L : compileId;
assert inOopsTable || compileId != 0L : this;
}
/**
* Determines if the nmethod associated with this object is the compiled entry point for
* {@link #getMethod()}.
*/
public boolean isDefault() {
return isDefault;
}
@Override
public boolean isValid() {
if (compileIdSnapshot != 0L) {
compilerToVM().updateHotSpotNmethod(this);
}
return super.isValid();
}
public ResolvedJavaMethod getMethod() {
return method;
}
@Override
public void invalidate() {
compilerToVM().invalidateHotSpotNmethod(this);
}
@Override
public long getAddress() {
if (compileIdSnapshot != 0L) {
compilerToVM().updateHotSpotNmethod(this);
}
return super.getAddress();
}
@Override
public long getEntryPoint() {
if (compileIdSnapshot != 0L) {
return 0;
}
return super.getEntryPoint();
}
@Override
public String toString() {
return String.format("HotSpotNmethod[method=%s, codeBlob=0x%x, isDefault=%b, name=%s, inOopsTable=%s]",
method, getAddress(), isDefault, name, inOopsTable());
}
private boolean checkArgs(Object... args) {
JavaType[] sig = method.toParameterTypes();
assert args.length == sig.length : method.format("%H.%n(%p): expected ") + sig.length + " args, got " + args.length;
for (int i = 0; i < sig.length; i++) {
Object arg = args[i];
if (arg == null) {
assert sig[i].getJavaKind() == JavaKind.Object : method.format("%H.%n(%p): expected arg ") + i + " to be Object, not " + sig[i];
} else if (sig[i].getJavaKind() != JavaKind.Object) {
assert sig[i].getJavaKind().toBoxedJavaClass() == arg.getClass() : method.format("%H.%n(%p): expected arg ") + i + " to be " + sig[i] + ", not " + arg.getClass();
}
}
return true;
}
@Override
public Object executeVarargs(Object... args) throws InvalidInstalledCodeException {
if (IS_IN_NATIVE_IMAGE) {
throw new HotSpotJVMCIUnsupportedOperationError("Cannot execute nmethod via mirror in native image");
}
assert checkArgs(args);
return compilerToVM().executeHotSpotNmethod(args, this);
}
@Override
public long getStart() {
return isValid() ? super.getStart() : 0;
}
}