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NMethod.java
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NMethod.java
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/*
* Copyright (c) 2000, 2020, 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.
*
*/
package sun.jvm.hotspot.code;
import java.io.*;
import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.utilities.*;
public class NMethod extends CompiledMethod {
private static long pcDescSize;
/** != InvocationEntryBci if this nmethod is an on-stack replacement method */
private static CIntegerField entryBCIField;
/** To support simple linked-list chaining of nmethods */
private static AddressField osrLinkField;
/** Offsets for different nmethod parts */
private static CIntegerField exceptionOffsetField;
private static CIntegerField origPCOffsetField;
private static CIntegerField stubOffsetField;
private static CIntegerField oopsOffsetField;
private static CIntegerField metadataOffsetField;
private static CIntegerField scopesPCsOffsetField;
private static CIntegerField dependenciesOffsetField;
private static CIntegerField handlerTableOffsetField;
private static CIntegerField nulChkTableOffsetField;
private static CIntegerField nmethodEndOffsetField;
/** Offsets for entry points */
/** Entry point with class check */
private static AddressField entryPointField;
/** Entry point without class check */
private static AddressField verifiedEntryPointField;
/** Entry point for on stack replacement */
private static AddressField osrEntryPointField;
// FIXME: add access to flags (how?)
/** NMethod Flushing lock (if non-zero, then the nmethod is not removed) */
private static JIntField lockCountField;
/** not_entrant method removal. Each mark_sweep pass will update
this mark to current sweep invocation count if it is seen on the
stack. An not_entrant method can be removed when there is no
more activations, i.e., when the _stack_traversal_mark is less than
current sweep traversal index. */
private static CIntegerField stackTraversalMarkField;
private static CIntegerField compLevelField;
static {
VM.registerVMInitializedObserver(new Observer() {
public void update(Observable o, Object data) {
initialize(VM.getVM().getTypeDataBase());
}
});
}
private static void initialize(TypeDataBase db) {
Type type = db.lookupType("nmethod");
entryBCIField = type.getCIntegerField("_entry_bci");
osrLinkField = type.getAddressField("_osr_link");
exceptionOffsetField = type.getCIntegerField("_exception_offset");
origPCOffsetField = type.getCIntegerField("_orig_pc_offset");
stubOffsetField = type.getCIntegerField("_stub_offset");
oopsOffsetField = type.getCIntegerField("_oops_offset");
metadataOffsetField = type.getCIntegerField("_metadata_offset");
scopesPCsOffsetField = type.getCIntegerField("_scopes_pcs_offset");
dependenciesOffsetField = type.getCIntegerField("_dependencies_offset");
handlerTableOffsetField = type.getCIntegerField("_handler_table_offset");
nulChkTableOffsetField = type.getCIntegerField("_nul_chk_table_offset");
nmethodEndOffsetField = type.getCIntegerField("_nmethod_end_offset");
entryPointField = type.getAddressField("_entry_point");
verifiedEntryPointField = type.getAddressField("_verified_entry_point");
osrEntryPointField = type.getAddressField("_osr_entry_point");
lockCountField = type.getJIntField("_lock_count");
stackTraversalMarkField = type.getCIntegerField("_stack_traversal_mark");
compLevelField = type.getCIntegerField("_comp_level");
pcDescSize = db.lookupType("PcDesc").getSize();
}
public NMethod(Address addr) {
super(addr);
}
// Accessors
public Address getAddress() {
return addr;
}
// Type info
public boolean isNMethod() { return true; }
public boolean isJavaMethod() { return !getMethod().isNative(); }
public boolean isNativeMethod() { return getMethod().isNative(); }
public boolean isOSRMethod() { return getEntryBCI() != VM.getVM().getInvocationEntryBCI(); }
/** Boundaries for different parts */
public Address constantsBegin() { return contentBegin(); }
public Address constantsEnd() { return getEntryPoint(); }
public Address instsBegin() { return codeBegin(); }
public Address instsEnd() { return headerBegin().addOffsetTo(getStubOffset()); }
public Address exceptionBegin() { return headerBegin().addOffsetTo(getExceptionOffset()); }
public Address stubBegin() { return headerBegin().addOffsetTo(getStubOffset()); }
public Address stubEnd() { return headerBegin().addOffsetTo(getOopsOffset()); }
public Address oopsBegin() { return headerBegin().addOffsetTo(getOopsOffset()); }
public Address oopsEnd() { return headerBegin().addOffsetTo(getMetadataOffset()); }
public Address metadataBegin() { return headerBegin().addOffsetTo(getMetadataOffset()); }
public Address metadataEnd() { return scopesDataBegin(); }
public Address scopesDataEnd() { return headerBegin().addOffsetTo(getScopesPCsOffset()); }
public Address scopesPCsBegin() { return headerBegin().addOffsetTo(getScopesPCsOffset()); }
public Address scopesPCsEnd() { return headerBegin().addOffsetTo(getDependenciesOffset()); }
public Address dependenciesBegin() { return headerBegin().addOffsetTo(getDependenciesOffset()); }
public Address dependenciesEnd() { return headerBegin().addOffsetTo(getHandlerTableOffset()); }
public Address handlerTableBegin() { return headerBegin().addOffsetTo(getHandlerTableOffset()); }
public Address handlerTableEnd() { return headerBegin().addOffsetTo(getNulChkTableOffset()); }
public Address nulChkTableBegin() { return headerBegin().addOffsetTo(getNulChkTableOffset()); }
public Address nulChkTableEnd() { return headerBegin().addOffsetTo(getNMethodEndOffset()); }
public int constantsSize() { return (int) constantsEnd() .minus(constantsBegin()); }
public int instsSize() { return (int) instsEnd() .minus(instsBegin()); }
public int stubSize() { return (int) stubEnd() .minus(stubBegin()); }
public int oopsSize() { return (int) oopsEnd() .minus(oopsBegin()); }
public int metadataSize() { return (int) metadataEnd() .minus(metadataBegin()); }
public int scopesDataSize() { return (int) scopesDataEnd() .minus(scopesDataBegin()); }
public int scopesPCsSize() { return (int) scopesPCsEnd() .minus(scopesPCsBegin()); }
public int dependenciesSize() { return (int) dependenciesEnd().minus(dependenciesBegin()); }
public int handlerTableSize() { return (int) handlerTableEnd().minus(handlerTableBegin()); }
public int nulChkTableSize() { return (int) nulChkTableEnd() .minus(nulChkTableBegin()); }
public int origPCOffset() { return (int) origPCOffsetField.getValue(addr); }
public int totalSize() {
return
constantsSize() +
instsSize() +
stubSize() +
scopesDataSize() +
scopesPCsSize() +
dependenciesSize() +
handlerTableSize() +
nulChkTableSize();
}
public boolean constantsContains (Address addr) { return constantsBegin() .lessThanOrEqual(addr) && constantsEnd() .greaterThan(addr); }
public boolean instsContains (Address addr) { return instsBegin() .lessThanOrEqual(addr) && instsEnd() .greaterThan(addr); }
public boolean stubContains (Address addr) { return stubBegin() .lessThanOrEqual(addr) && stubEnd() .greaterThan(addr); }
public boolean oopsContains (Address addr) { return oopsBegin() .lessThanOrEqual(addr) && oopsEnd() .greaterThan(addr); }
public boolean metadataContains (Address addr) { return metadataBegin() .lessThanOrEqual(addr) && metadataEnd() .greaterThan(addr); }
public boolean scopesDataContains (Address addr) { return scopesDataBegin() .lessThanOrEqual(addr) && scopesDataEnd() .greaterThan(addr); }
public boolean scopesPCsContains (Address addr) { return scopesPCsBegin() .lessThanOrEqual(addr) && scopesPCsEnd() .greaterThan(addr); }
public boolean handlerTableContains(Address addr) { return handlerTableBegin().lessThanOrEqual(addr) && handlerTableEnd().greaterThan(addr); }
public boolean nulChkTableContains (Address addr) { return nulChkTableBegin() .lessThanOrEqual(addr) && nulChkTableEnd() .greaterThan(addr); }
public int getOopsLength() { return (int) (oopsSize() / VM.getVM().getOopSize()); }
public int getMetadataLength() { return (int) (metadataSize() / VM.getVM().getOopSize()); }
/** Entry points */
public Address getEntryPoint() { return entryPointField.getValue(addr); }
public Address getVerifiedEntryPoint() { return verifiedEntryPointField.getValue(addr); }
/** Support for oops in scopes and relocs. Note: index 0 is reserved for null. */
public OopHandle getOopAt(int index) {
if (index == 0) return null;
if (Assert.ASSERTS_ENABLED) {
Assert.that(index > 0 && index <= getOopsLength(), "must be a valid non-zero index");
}
return oopsBegin().getOopHandleAt((index - 1) * VM.getVM().getOopSize());
}
/** Support for metadata in scopes and relocs. Note: index 0 is reserved for null. */
public Address getMetadataAt(int index) {
if (index == 0) return null;
if (Assert.ASSERTS_ENABLED) {
Assert.that(index > 0 && index <= getMetadataLength(), "must be a valid non-zero index");
}
return metadataBegin().getAddressAt((index - 1) * VM.getVM().getOopSize());
}
public Method getMethodAt(int index) {
return (Method)Metadata.instantiateWrapperFor(getMetadataAt(index));
}
// FIXME: add interpreter_entry_point()
// FIXME: add lazy_interpreter_entry_point() for C2
// **********
// * FIXME: * ADD ACCESS TO FLAGS!!!!
// **********
// public boolean isInUse();
// public boolean isAlive();
// public boolean isNotEntrant();
// public boolean isZombie();
// ********************************
// * MAJOR FIXME: MAJOR HACK HERE *
// ********************************
public boolean isZombie() { return false; }
// public boolean isUnloaded();
// public boolean isYoung();
// public boolean isOld();
// public int age();
// public boolean isMarkedForDeoptimization();
// public boolean isMarkedForUnloading();
// public int level();
// public int version();
// FIXME: add mutators for above
// FIXME: add exception cache access?
/** On-stack replacement support */
// FIXME: add mutators
public int getOSREntryBCI() {
if (Assert.ASSERTS_ENABLED) {
Assert.that(getEntryBCI() != VM.getVM().getInvocationEntryBCI(), "wrong kind of nmethod");
}
return getEntryBCI();
}
public NMethod getOSRLink() {
return (NMethod) VMObjectFactory.newObject(NMethod.class, osrLinkField.getValue(addr));
}
// MethodHandle
public boolean isMethodHandleReturn(Address returnPc) {
// Hard to read a bit fields from Java and it's only there for performance
// so just go directly to the PCDesc
// if (!hasMethodHandleInvokes()) return false;
PCDesc pd = getPCDescAt(returnPc);
if (pd == null)
return false;
return pd.isMethodHandleInvoke();
}
// Deopt
// Return true is the PC is one would expect if the frame is being deopted.
public boolean isDeoptPc (Address pc) { return isDeoptEntry(pc) || isDeoptMhEntry(pc); }
public boolean isDeoptEntry (Address pc) { return pc == deoptHandlerBegin(); }
public boolean isDeoptMhEntry (Address pc) { return pc == deoptMhHandlerBegin(); }
/** Tells whether frames described by this nmethod can be
deoptimized. Note: native wrappers cannot be deoptimized. */
public boolean canBeDeoptimized() { return isJavaMethod(); }
// FIXME: add inline cache support
// FIXME: add flush()
public boolean isLockedByVM() { return lockCountField.getValue(addr) > 0; }
// FIXME: add mark_as_seen_on_stack
// FIXME: add can_not_entrant_be_converted
// FIXME: add GC support
// void follow_roots_or_mark_for_unloading(bool unloading_occurred, bool& marked_for_unloading);
// void follow_root_or_mark_for_unloading(oop* root, bool unloading_occurred, bool& marked_for_unloading);
// void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, void f(oop*));
// void adjust_pointers();
/** Finds a PCDesc with real-pc equal to "pc" */
public PCDesc getPCDescAt(Address pc) {
// FIXME: consider adding cache like the one down in the VM
for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {
PCDesc pcDesc = new PCDesc(p);
if (pcDesc.getRealPC(this).equals(pc)) {
return pcDesc;
}
}
return null;
}
/** ScopeDesc for an instruction */
public ScopeDesc getScopeDescAt(Address pc) {
PCDesc pd = getPCDescAt(pc);
if (Assert.ASSERTS_ENABLED) {
Assert.that(pd != null, "scope must be present");
}
return new ScopeDesc(this, pd.getScopeDecodeOffset(), pd.getObjDecodeOffset(), pd.getReexecute());
}
/** This is only for use by the debugging system, and is only
intended for use in the topmost frame, where we are not
guaranteed to be at a PC for which we have a PCDesc. It finds
the PCDesc with realPC closest to the current PC that has
a valid scope decode offset. */
public PCDesc getPCDescNearDbg(Address pc) {
PCDesc bestGuessPCDesc = null;
long bestDistance = 0;
for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {
PCDesc pcDesc = new PCDesc(p);
if (pcDesc.getScopeDecodeOffset() == DebugInformationRecorder.SERIALIZED_NULL) {
// We've observed a serialized null decode offset. Ignore this PcDesc.
continue;
}
// In case pc is null
long distance = -pcDesc.getRealPC(this).minus(pc);
if ((bestGuessPCDesc == null) ||
((distance >= 0) && (distance < bestDistance))) {
bestGuessPCDesc = pcDesc;
bestDistance = distance;
}
}
return bestGuessPCDesc;
}
PCDesc find_pc_desc(long pc, boolean approximate) {
return find_pc_desc_internal(pc, approximate);
}
// Finds a PcDesc with real-pc equal to "pc"
PCDesc find_pc_desc_internal(long pc, boolean approximate) {
long base_address = VM.getAddressValue(codeBegin());
int pc_offset = (int) (pc - base_address);
// Fallback algorithm: quasi-linear search for the PcDesc
// Find the last pc_offset less than the given offset.
// The successor must be the required match, if there is a match at all.
// (Use a fixed radix to avoid expensive affine pointer arithmetic.)
Address lower = scopesPCsBegin();
Address upper = scopesPCsEnd();
upper = upper.addOffsetTo(-pcDescSize); // exclude final sentinel
if (lower.greaterThan(upper)) return null; // native method; no PcDescs at all
// Take giant steps at first (4096, then 256, then 16, then 1)
int LOG2_RADIX = 4;
int RADIX = (1 << LOG2_RADIX);
Address mid;
for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
while ((mid = lower.addOffsetTo(step * pcDescSize)).lessThan(upper)) {
PCDesc m = new PCDesc(mid);
if (m.getPCOffset() < pc_offset) {
lower = mid;
} else {
upper = mid;
break;
}
}
}
// Sneak up on the value with a linear search of length ~16.
while (true) {
mid = lower.addOffsetTo(pcDescSize);
PCDesc m = new PCDesc(mid);
if (m.getPCOffset() < pc_offset) {
lower = mid;
} else {
upper = mid;
break;
}
}
PCDesc u = new PCDesc(upper);
if (match_desc(u, pc_offset, approximate)) {
return u;
} else {
return null;
}
}
// ScopeDesc retrieval operation
PCDesc pc_desc_at(long pc) { return find_pc_desc(pc, false); }
// pc_desc_near returns the first PCDesc at or after the givne pc.
PCDesc pc_desc_near(long pc) { return find_pc_desc(pc, true); }
// Return a the last scope in (begin..end]
public ScopeDesc scope_desc_in(long begin, long end) {
PCDesc p = pc_desc_near(begin+1);
if (p != null && VM.getAddressValue(p.getRealPC(this)) <= end) {
return new ScopeDesc(this, p.getScopeDecodeOffset(), p.getObjDecodeOffset(), p.getReexecute());
}
return null;
}
static boolean match_desc(PCDesc pc, int pc_offset, boolean approximate) {
if (!approximate) {
return pc.getPCOffset() == pc_offset;
} else {
PCDesc prev = new PCDesc(pc.getAddress().addOffsetTo(-pcDescSize));
return prev.getPCOffset() < pc_offset && pc_offset <= pc.getPCOffset();
}
}
/** This is only for use by the debugging system, and is only
intended for use in the topmost frame, where we are not
guaranteed to be at a PC for which we have a PCDesc. It finds
the ScopeDesc closest to the current PC. NOTE that this may
return NULL for compiled methods which don't have any
ScopeDescs! */
public ScopeDesc getScopeDescNearDbg(Address pc) {
PCDesc pd = getPCDescNearDbg(pc);
if (pd == null) return null;
return new ScopeDesc(this, pd.getScopeDecodeOffset(), pd.getObjDecodeOffset(), pd.getReexecute());
}
public Map<sun.jvm.hotspot.debugger.Address, PCDesc> getSafepoints() {
Map<sun.jvm.hotspot.debugger.Address, PCDesc> safepoints = new HashMap<>();
sun.jvm.hotspot.debugger.Address p = null;
for (p = scopesPCsBegin(); p.lessThan(scopesPCsEnd());
p = p.addOffsetTo(pcDescSize)) {
PCDesc pcDesc = new PCDesc(p);
sun.jvm.hotspot.debugger.Address pc = pcDesc.getRealPC(this);
safepoints.put(pc, pcDesc);
}
return safepoints;
}
// FIXME: add getPCOffsetForBCI()
// FIXME: add embeddedOopAt()
// FIXME: add isDependentOn()
// FIXME: add isPatchableAt()
/** Support for code generation. Only here for proof-of-concept. */
public static int getEntryPointOffset() { return (int) entryPointField.getOffset(); }
public static int getVerifiedEntryPointOffset() { return (int) verifiedEntryPointField.getOffset(); }
public static int getOSREntryPointOffset() { return (int) osrEntryPointField.getOffset(); }
public static int getEntryBCIOffset() { return (int) entryBCIField.getOffset(); }
public void print() {
printOn(System.out);
}
protected void printComponentsOn(PrintStream tty) {
// FIXME: add relocation information
tty.println(" content: [" + contentBegin() + ", " + contentEnd() + "), " +
" code: [" + codeBegin() + ", " + codeEnd() + "), " +
" data: [" + dataBegin() + ", " + dataEnd() + "), " +
" oops: [" + oopsBegin() + ", " + oopsEnd() + "), " +
" frame size: " + getFrameSize());
}
public String toString() {
Method method = getMethod();
return "NMethod for " +
method.getMethodHolder().getName().asString() + "." +
method.getName().asString() + method.getSignature().asString() + "==>n" +
super.toString();
}
public String flagsToString() {
// FIXME need access to flags...
return "";
}
public String getName() {
Method method = getMethod();
return "NMethod for " +
method.getMethodHolder().getName().asString() + "." +
method.getName().asString() +
method.getSignature().asString();
}
public void dumpReplayData(PrintStream out) {
HashMap<Metadata, Metadata> h = new HashMap<>();
for (int i = 1; i < getMetadataLength(); i++) {
Metadata meta = Metadata.instantiateWrapperFor(getMetadataAt(i));
System.err.println(meta);
if (h.get(meta) != null) continue;
h.put(meta, meta);
if (meta instanceof InstanceKlass) {
((InstanceKlass)meta).dumpReplayData(out);
} else if (meta instanceof Method) {
((Method)meta).dumpReplayData(out);
MethodData mdo = ((Method)meta).getMethodData();
if (mdo != null) {
mdo.dumpReplayData(out);
}
}
}
Method method = getMethod();
if (h.get(method) == null) {
method.dumpReplayData(out);
MethodData mdo = method.getMethodData();
if (mdo != null) {
mdo.dumpReplayData(out);
}
}
if (h.get(method.getMethodHolder()) == null) {
((InstanceKlass)method.getMethodHolder()).dumpReplayData(out);
}
Klass holder = method.getMethodHolder();
out.println("compile " + holder.getName().asString() + " " +
OopUtilities.escapeString(method.getName().asString()) + " " +
method.getSignature().asString() + " " +
getEntryBCI() + " " + getCompLevel());
}
//--------------------------------------------------------------------------------
// Internals only below this point
//
private int getEntryBCI() { return (int) entryBCIField .getValue(addr); }
private int getExceptionOffset() { return (int) exceptionOffsetField .getValue(addr); }
private int getStubOffset() { return (int) stubOffsetField .getValue(addr); }
private int getOopsOffset() { return (int) oopsOffsetField .getValue(addr); }
private int getMetadataOffset() { return (int) metadataOffsetField .getValue(addr); }
private int getScopesPCsOffset() { return (int) scopesPCsOffsetField .getValue(addr); }
private int getDependenciesOffset() { return (int) dependenciesOffsetField.getValue(addr); }
private int getHandlerTableOffset() { return (int) handlerTableOffsetField.getValue(addr); }
private int getNulChkTableOffset() { return (int) nulChkTableOffsetField .getValue(addr); }
private int getNMethodEndOffset() { return (int) nmethodEndOffsetField .getValue(addr); }
private int getCompLevel() { return (int) compLevelField .getValue(addr); }
}