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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
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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.*;
import sun.jvm.hotspot.utilities.Observable;
import sun.jvm.hotspot.utilities.Observer;

public class NMethod extends CompiledMethod {
  private static long          pcDescSize;
  
!= InvocationEntryBci if this nmethod is an on-stack replacement method
/** != InvocationEntryBci if this nmethod is an on-stack replacement method */
private static CIntegerField entryBCIField;
To support simple linked-list chaining of nmethods
/** To support simple linked-list chaining of nmethods */
private static AddressField osrLinkField;
Offsets for different nmethod parts
/** 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
/** Entry point with class check */
private static AddressField entryPointField;
Entry point without class check
/** Entry point without class check */
private static AddressField verifiedEntryPointField;
Entry point for on stack replacement
/** 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)
/** 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.
/** 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
/** 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
/** 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.
/** 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.
/** 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
/** 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.
/** 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"
/** 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
/** 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.
/** 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!
/** 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.
/** 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); } }