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hshelp.c
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hshelp.c
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/*******************************************************************************
* Copyright (c) 1991, 2018 IBM Corp. and others
*
* This program and the accompanying materials are made available under
* the terms of the Eclipse Public License 2.0 which accompanies this
* distribution and is available at https://www.eclipse.org/legal/epl-2.0/
* or the Apache License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the following
* Secondary Licenses when the conditions for such availability set
* forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
* General Public License, version 2 with the GNU Classpath
* Exception [1] and GNU General Public License, version 2 with the
* OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
*******************************************************************************/
#include <string.h>
#include <stdlib.h>
#include "j9.h"
#include "j9protos.h"
#include "j9user.h"
#include "util_api.h"
#include "jni.h"
#include "j9comp.h"
#include "vmaccess.h"
#include "j9consts.h"
#include "rommeth.h"
#include "j9port.h"
#include "j9cp.h"
#include "bcnames.h"
#include "pcstack.h"
#include "jvmti.h"
#include "jvmtiInternal.h"
#include "HeapIteratorAPI.h"
#include "ut_j9hshelp.h"
#include "j9modron.h"
#include "VM_MethodHandleKinds.h"
#include "j2sever.h"
#include "vrfytbl.h"
#include "bytecodewalk.h"
/* Static J9ITable used as a non-NULL iTable cache value by classes that don't implement any interfaces */
const J9ITable invalidITable = { (J9Class *) (UDATA) 0xDEADBEEF, 0, (J9ITable *) NULL };
#if defined(J9VM_INTERP_HOT_CODE_REPLACEMENT)
#define GET_SUPERCLASS(clazz) \
((J9CLASS_DEPTH(clazz) == 0) ? NULL : \
(clazz)->superclasses[J9CLASS_DEPTH(clazz) - 1])
#define NAME_AND_SIG_IDENTICAL(o1, o2, getNameMacro, getSigMacro) \
areUTFPairsIdentical(getNameMacro(o1), getSigMacro(o1), getNameMacro(o2), getSigMacro(o2))
#define J9ROMMETHOD_NAME_AND_SIG_IDENTICAL(romClass1, romClass2, o1, o2) \
areUTFPairsIdentical(J9ROMMETHOD_GET_NAME(romClass1, o1), J9ROMMETHOD_GET_SIGNATURE(romClass1, o1), J9ROMMETHOD_GET_NAME(romClass2, o2), J9ROMMETHOD_GET_SIGNATURE(romClass2, o2))
static UDATA equivalenceHash (void *key, void *userData);
static UDATA equivalenceEquals (void *leftKey, void *rightKey, void *userData);
static jvmtiError addMethodEquivalence(J9VMThread * currentThread, J9Method * oldMethod, J9Method * newMethod, J9HashTable ** methodEquivalences, U_32 size);
static J9Method * getMethodEquivalence (J9VMThread * currentThread, J9Method * method, J9HashTable ** methodEquivalences);
static UDATA fixJNIFieldID PROTOTYPE((J9VMThread * currentThread, J9JNIFieldID * fieldID, J9Class * replacementRAMClass));
static UDATA areMethodRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2);
static UDATA areClassRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2);
static UDATA areFieldRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2);
static UDATA areNameAndSigsIdentical(J9ROMNameAndSignature * nas1, J9ROMNameAndSignature * nas2);
static UDATA areSingleSlotConstantRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2);
static UDATA areDoubleSlotConstantRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2);
static void fixClassSlot(J9VMThread* currentThread, J9Class** classSlot, J9HashTable *classPairs);
static void fixJNIFieldIDs(J9VMThread * currentThread, J9Class * originalClass, J9Class * replacementClass);
static void copyStaticFields (J9VMThread * currentThread, J9Class * originalRAMClass, J9Class * replacementRAMClass);
static void fixLoadingConstraints (J9JavaVM * vm, J9Class * oldClass, J9Class * newClass);
static UDATA classPairHash(void* entry, void* userData);
static UDATA classPairEquals(void* left, void* right, void* userData);
static UDATA findMethodInVTable(J9Method *method, UDATA *vTable);
static jvmtiError addClassesRequiringNewITables(J9JavaVM *vm, J9HashTable *classHashTable, UDATA *addedMethodCountPtr, UDATA *addedClassCountPtr);
static jvmtiError verifyFieldsAreSame (J9VMThread * currentThread, UDATA fieldType, J9ROMClass * originalROMClass, J9ROMClass * replacementROMClass,
UDATA extensionsEnabled, UDATA * extensionsUsed);
static jvmtiError verifyMethodsAreSame (J9VMThread * currentThread, J9JVMTIClassPair * classPair, UDATA extensionsEnabled, UDATA * extensionsUsed);
static int compareClassDepth (const void *leftPair, const void *rightPair);
static UDATA utfsAreIdentical(J9UTF8 * utf1, J9UTF8 * utf2);
static UDATA areUTFPairsIdentical(J9UTF8 * leftUtf1, J9UTF8 * leftUtf2, J9UTF8 * rightUtf1, J9UTF8 * rightUtf2);
static jvmtiError fixJNIMethodID(J9VMThread *currentThread, J9Method *oldMethod, J9Method *newMethod, BOOLEAN equivalent, UDATA extensionsUsed);
static jvmtiIterationControl fixHeapRefsHeapIteratorCallback(J9JavaVM *vm, J9MM_IterateHeapDescriptor *heapDesc, void *userData);
static jvmtiIterationControl fixHeapRefsSpaceIteratorCallback(J9JavaVM *vm, J9MM_IterateSpaceDescriptor *spaceDesc, void *userData);
static jvmtiIterationControl fixHeapRefsRegionIteratorCallback(J9JavaVM *vm, J9MM_IterateRegionDescriptor *regionDesc, void *userData);
static jvmtiIterationControl fixHeapRefsObjectIteratorCallback(J9JavaVM *vm, J9MM_IterateObjectDescriptor *objectDesc, void *userData);
static void replaceInAllClassLoaders(J9VMThread * currentThread, J9Class * originalRAMClass, J9Class * replacementRAMClass);
#ifdef J9VM_INTERP_NATIVE_SUPPORT
static jvmtiError jitEventInitialize(J9VMThread * currentThread, jint redefinedClassCount, UDATA redefinedMethodCount, J9JVMTIHCRJitEventData * eventData);
static void jitEventAddMethod(J9VMThread * currentThread, J9JVMTIHCRJitEventData * eventData, J9Method * oldMethod, J9Method * newMethod, UDATA equivalent);
static void jitEventAddClass(J9VMThread * currentThread, J9JVMTIHCRJitEventData * eventData, J9Class * originalRAMClass, J9Class * replacementRAMClass);
#endif
static void removeFromSubclassHierarchy(J9JavaVM *javaVM, J9Class *clazzPtr);
static void swapClassesForFastHCR(J9Class *originalClass, J9Class *newClass);
#undef J9HSHELP_DEBUG_SANITY_CHECK
#define J9HSHELP_DEBUG 1
#ifdef J9HSHELP_DEBUG
static char *
getClassName(J9Class * c)
{
static char buf[512];
J9UTF8 * className = J9ROMCLASS_CLASSNAME(c->romClass);
memcpy(buf, J9UTF8_DATA(className), J9UTF8_LENGTH(className));
buf[J9UTF8_LENGTH(className)] = 0;
return buf;
}
#endif
#ifdef J9HSHELP_DEBUG
static char *
getMethodName(J9Method * m)
{
static char buf[512];
J9UTF8 * n = J9ROMMETHOD_GET_NAME(J9_CLASS_FROM_METHOD(method)->romClass, J9_ROM_METHOD_FROM_RAM_METHOD(m));
memcpy(buf, J9UTF8_DATA(n), J9UTF8_LENGTH(n));
buf[J9UTF8_LENGTH(n)] = 0;
return buf;
}
#endif
#ifdef J9HSHELP_DEBUG_SANITY_CHECK
void
hcrSanityCheck(J9JavaVM * vm)
{
J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
J9Class * clazz;
J9JVMTIClassPair * result;
J9JVMTIClassPair exemplar;
J9ClassWalkState state;
clazz = vmFuncs->allClassesStartDo(&state, vm, NULL);
while (clazz != NULL) {
/* Make sure all the arrayClass ptrs in obsolete classes point at something (naive null check) */
if (J9_IS_CLASS_OBSOLETE(clazz)) {
if (clazz->arrayClass == NULL) {
abort();
}
}
clazz = vmFuncs->allClassesNextDo(&state);
}
vmFuncs->allClassesEndDo(&state);
}
#endif
/**
* @brief
* Compares two J9UTF8s for identical contents.
* @param first J9UTF8 (must not be NULL)
* @param second J9UTF8 (must not be NULL)
* @return TRUE if they are identical, FALSE otherwise
*/
static UDATA
utfsAreIdentical(J9UTF8 * utf1, J9UTF8 * utf2)
{
if (J9UTF8_LENGTH(utf1) != J9UTF8_LENGTH(utf2)) {
return FALSE;
}
return (memcmp(J9UTF8_DATA(utf1), J9UTF8_DATA(utf2), J9UTF8_LENGTH(utf1)) == 0) ? TRUE : FALSE;
}
/**
* @brief
* Compares two pairs of J9UTF8s for identical contents.
* @param leftUtf1 J9UTF8 (must not be NULL)
* @param leftUtf2 J9UTF8 (must not be NULL)
* @param rightUtf1 J9UTF8 (must not be NULL)
* @param rightUtf2 J9UTF8 (must not be NULL)
* @return TRUE if they are identical, FALSE otherwise
*/
static UDATA
areUTFPairsIdentical(J9UTF8 * leftUtf1, J9UTF8 * leftUtf2, J9UTF8 * rightUtf1, J9UTF8 * rightUtf2)
{
if ((J9UTF8_LENGTH(leftUtf1) != J9UTF8_LENGTH(rightUtf1)) || (J9UTF8_LENGTH(leftUtf2) != J9UTF8_LENGTH(rightUtf2))) {
return FALSE;
}
if (0 != memcmp(J9UTF8_DATA(leftUtf1), J9UTF8_DATA(rightUtf1), J9UTF8_LENGTH(leftUtf1))) {
return FALSE;
}
if (0 != memcmp(J9UTF8_DATA(leftUtf2), J9UTF8_DATA(rightUtf2), J9UTF8_LENGTH(leftUtf2))) {
return FALSE;
}
return TRUE;
}
static UDATA
fixJNIFieldID(J9VMThread * currentThread, J9JNIFieldID * fieldID, J9Class * replacementRAMClass)
{
J9ROMFieldShape * field = fieldID->field;
J9ROMFieldShape * newField = NULL;
UDATA offset;
J9UTF8 * fieldName = J9ROMFIELDSHAPE_NAME(field);
J9UTF8 * fieldSignature = J9ROMFIELDSHAPE_SIGNATURE(field);
J9JavaVM * vm = currentThread->javaVM;
J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
J9ROMClass * replacementROMClass;
UDATA newFieldIndex;
J9ROMFieldWalkState state;
J9ROMFieldShape * current;
if (field->modifiers & J9AccStatic) {
J9ROMFieldShape * resolvedField;
void * newFieldAddress;
J9Class * declaringClass;
newFieldAddress = vmFuncs->staticFieldAddress(
currentThread,
replacementRAMClass,
J9UTF8_DATA(fieldName),
J9UTF8_LENGTH(fieldName),
J9UTF8_DATA(fieldSignature),
J9UTF8_LENGTH(fieldSignature),
&declaringClass,
(UDATA *) &resolvedField,
J9_LOOK_NO_JAVA,
NULL);
if ((newFieldAddress != NULL) && (J9_CURRENT_CLASS(declaringClass) == replacementRAMClass)) {
offset = (UDATA) newFieldAddress - (UDATA) replacementRAMClass->ramStatics;
newField = resolvedField;
}
} else {
J9ROMFieldShape * resolvedField;
UDATA newFieldOffset;
J9Class * declaringClass;
newFieldOffset = vmFuncs->instanceFieldOffset(
currentThread,
replacementRAMClass,
J9UTF8_DATA(fieldName),
J9UTF8_LENGTH(fieldName),
J9UTF8_DATA(fieldSignature),
J9UTF8_LENGTH(fieldSignature),
&declaringClass,
(UDATA *) &resolvedField,
J9_LOOK_NO_JAVA);
if ((newFieldOffset != -1) && (declaringClass == replacementRAMClass)) {
offset = newFieldOffset;
newField = resolvedField;
}
}
if (newField == NULL) {
return FALSE;
}
/* Determine the field index (field IDs are stored after method IDs in the array) */
replacementROMClass = replacementRAMClass->romClass;
newFieldIndex = replacementROMClass->romMethodCount;
current = romFieldsStartDo(replacementROMClass, &state);
while (newField != current) {
++newFieldIndex;
current = romFieldsNextDo(&state);
}
fieldID->index = newFieldIndex;
fieldID->field = newField;
fieldID->offset = offset;
fieldID->declaringClass = replacementRAMClass;
return TRUE;
}
static void
fixJNIFieldIDs(J9VMThread * currentThread, J9Class * originalClass, J9Class * replacementClass)
{
void ** oldJNIIDs = originalClass->jniIDs;
if (oldJNIIDs != NULL) {
J9JavaVM * vm = currentThread->javaVM;
void ** newJNIIDs;
newJNIIDs = vm->internalVMFunctions->ensureJNIIDTable(currentThread, replacementClass);
if (newJNIIDs == NULL) {
/* do something */
Assert_hshelp_ShouldNeverHappen();
} else {
J9ROMClass * originalROMClass = originalClass->romClass;
UDATA oldMethodCount = originalROMClass->romMethodCount;
UDATA oldFieldCount = originalROMClass->romFieldCount;
UDATA oldFieldIndex;
for (oldFieldIndex = oldMethodCount; oldFieldIndex < oldMethodCount + oldFieldCount; ++oldFieldIndex) {
J9JNIFieldID * fieldID = oldJNIIDs[oldFieldIndex];
if (fieldID != NULL) {
/* Always invalidate the old field ID slot (do not free IDs for deleted fields, since a reflect field might be holding onto it) */
oldJNIIDs[oldFieldIndex] = NULL;
/* If the old field was not deleted, move the fieldID to the new class */
if (fixJNIFieldID(currentThread, fieldID, replacementClass)) {
newJNIIDs[fieldID->index] = fieldID;
}
}
}
}
}
}
/*
* @param currenThread
* @param oldMethod
* @param newMethod
* @param equivalent
*
* if equivalent and old exists, copy old methodID to new method
* if equivalent and old doesn't exists, create methodID for old method copy to new method
* if non-equivalent and old exists, copy old methodID to new method, and create a new methodID for the old chain
* if non-equivalent and old does not exist, do nothing
* if new doesn't exist do nothing
*/
static jvmtiError
fixJNIMethodID(J9VMThread *currentThread, J9Method *oldMethod, J9Method *newMethod, BOOLEAN equivalent, UDATA extensionsUsed)
{
jvmtiError rc = JVMTI_ERROR_NONE;
if (NULL != newMethod) {
J9JavaVM *vm = currentThread->javaVM;
J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
J9Class *oldMethodClass = J9_CLASS_FROM_METHOD(oldMethod);
void **oldJNIIDs = oldMethodClass->jniIDs;
UDATA oldMethodIndex = 0;
J9JNIMethodID *oldMethodID = NULL;
J9Class *newMethodClass = J9_CLASS_FROM_METHOD(newMethod);
void **newJNIIDs = NULL;
oldMethodIndex = getMethodIndex(oldMethod);
if (equivalent) {
if (NULL == oldJNIIDs) {
oldJNIIDs = vmFuncs->ensureJNIIDTable(currentThread, oldMethodClass);
if (NULL == oldJNIIDs) {
rc = JVMTI_ERROR_OUT_OF_MEMORY;
goto done;
}
}
oldMethodID = oldJNIIDs[oldMethodIndex];
/* we need to have a methodID so we can keep track of equivalences */
if (NULL == oldMethodID) {
oldMethodID = vmFuncs->getJNIMethodID(currentThread, oldMethod);
}
} else {
/* NOT Equivalent case */
J9JNIMethodID *oldMethodIDReplacement = NULL;
J9Class *currentClass = oldMethodClass;
if (NULL == oldJNIIDs) {
goto done;
}
oldMethodID = oldJNIIDs[oldMethodIndex];
if (NULL == oldMethodID) {
goto done;
}
/* invalidate the old methodID and create a new one */
oldJNIIDs[oldMethodIndex] = NULL;
oldMethodIDReplacement = vmFuncs->getJNIMethodID(currentThread, oldMethod);
if (NULL == oldMethodIDReplacement) {
/* Put the MethodID back so that the chain is still correct */
oldJNIIDs[oldMethodIndex] = oldMethodID;
rc = JVMTI_ERROR_OUT_OF_MEMORY;
goto done;
}
vmFuncs->initializeMethodID(currentThread, oldMethodIDReplacement, oldMethod);
oldJNIIDs[oldMethodIndex] = oldMethodIDReplacement;
/* walk back the class chain and fix up old equivalence */
while (NULL != currentClass->replacedClass) {
void **methodIDs = NULL;
J9Method *equivalentMethod = NULL;
BOOLEAN found = FALSE;
currentClass = currentClass->replacedClass;
methodIDs = currentClass->jniIDs;
if (NULL != methodIDs) {
UDATA methodIndex = 0;
UDATA methodCount = currentClass->romClass->romMethodCount;
for (methodIndex = 0; methodIndex < methodCount; methodIndex++) {
if (methodIDs[methodIndex] == oldMethodID) {
methodIDs[methodIndex] = oldMethodIDReplacement;
found = TRUE;
break;
}
}
}
if (!found) {
/* method is not found in the currentClass, stop searching now */
break;
}
}
}
if (NULL == newJNIIDs) {
newJNIIDs = vmFuncs->ensureJNIIDTable(currentThread, newMethodClass);
if (newJNIIDs == NULL) {
rc = JVMTI_ERROR_OUT_OF_MEMORY;
goto done;
}
}
newJNIIDs[getMethodIndex(newMethod)] = oldMethodID;
vmFuncs->initializeMethodID(currentThread, oldMethodID, newMethod);
}
done:
return rc;
}
static UDATA
areMethodRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2)
{
J9ROMMethodRef * ref1 = (J9ROMMethodRef *) &romCP1[index1];
J9ROMMethodRef * ref2 = (J9ROMMethodRef *) &romCP2[index2];
return
areClassRefsIdentical(romCP1, ref1->classRefCPIndex, romCP2, ref2->classRefCPIndex) &&
areNameAndSigsIdentical(J9ROMMETHODREF_NAMEANDSIGNATURE(ref1), J9ROMMETHODREF_NAMEANDSIGNATURE(ref2));
}
static UDATA
areClassRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2)
{
J9ROMClassRef * ref1 = (J9ROMClassRef *) &romCP1[index1];
J9ROMClassRef * ref2 = (J9ROMClassRef *) &romCP2[index2];
return utfsAreIdentical(J9ROMCLASSREF_NAME(ref1), J9ROMCLASSREF_NAME(ref2));
}
static UDATA
areFieldRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2)
{
J9ROMFieldRef * ref1 = (J9ROMFieldRef *) &romCP1[index1];
J9ROMFieldRef * ref2 = (J9ROMFieldRef *) &romCP2[index2];
return
areClassRefsIdentical(romCP1, ref1->classRefCPIndex, romCP2, ref2->classRefCPIndex) &&
areNameAndSigsIdentical(J9ROMFIELDREF_NAMEANDSIGNATURE(ref1), J9ROMFIELDREF_NAMEANDSIGNATURE(ref2));
}
static UDATA
areNameAndSigsIdentical(J9ROMNameAndSignature * nas1, J9ROMNameAndSignature * nas2)
{
return NAME_AND_SIG_IDENTICAL(nas1, nas2, J9ROMNAMEANDSIGNATURE_NAME, J9ROMNAMEANDSIGNATURE_SIGNATURE);
}
static UDATA
areSingleSlotConstantRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2)
{
J9ROMSingleSlotConstantRef * ref1 = (J9ROMSingleSlotConstantRef *) &romCP1[index1];
J9ROMSingleSlotConstantRef * ref2 = (J9ROMSingleSlotConstantRef *) &romCP2[index2];
if (ref1->cpType != ref2->cpType) {
return FALSE;
}
if ((ref1->cpType == J9DescriptionCpTypeScalar) || (ref1->cpType == J9DescriptionCpTypeMethodHandle)) {
return ref1->data == ref2->data;
}
/* all remaining cases { class, string, methodtype } are single UTF8 slots */
return utfsAreIdentical(J9ROMSTRINGREF_UTF8DATA((J9ROMStringRef *) ref1), J9ROMSTRINGREF_UTF8DATA((J9ROMStringRef *) ref2));
}
static UDATA
areDoubleSlotConstantRefsIdentical(J9ROMConstantPoolItem * romCP1, U_32 index1, J9ROMConstantPoolItem * romCP2, U_32 index2)
{
J9ROMConstantRef * ref1 = (J9ROMConstantRef *) &romCP1[index1];
J9ROMConstantRef * ref2 = (J9ROMConstantRef *) &romCP2[index2];
return (ref1->slot1 == ref2->slot1) && (ref1->slot2 == ref2->slot2);
}
UDATA
areMethodsEquivalent(J9ROMMethod * method1, J9ROMClass * romClass1, J9ROMMethod * method2, J9ROMClass * romClass2)
{
U_8 * bytecodes1;
J9ROMConstantPoolItem * romCP1;
U_8 * bytecodes2;
J9ROMConstantPoolItem * romCP2;
UDATA size;
UDATA index;
#ifdef J9VM_ENV_LITTLE_ENDIAN
#define NEXT_U16(bytecodes) (((U_16 ) ((bytecodes)[index + alreadyCompared + 0])) + (((U_16 ) ((bytecodes)[index + alreadyCompared + 1])) << 8))
#else
#define NEXT_U16(bytecodes) (((U_16 ) ((bytecodes)[index + alreadyCompared + 1])) + (((U_16 ) ((bytecodes)[index + alreadyCompared + 0])) << 8))
#endif
/* Modifiers must match exactly */
if (method1->modifiers != method2->modifiers) {
return FALSE;
}
/* Bytecode array sizes must match exactly */
size = J9_BYTECODE_SIZE_FROM_ROM_METHOD(method1);
if (size != J9_BYTECODE_SIZE_FROM_ROM_METHOD(method2)) {
return FALSE;
}
/* For a native or an abstract method, there are no bytecodes.
* A native method has a method signature in place of bytecodes.
* Method signature is derived from the method descriptor.
* As the method descriptor has already been compared by the caller fixMethodEquivalences(),
* there is no need to compare native method signature.
*/
if (J9_ARE_NO_BITS_SET(J9AccNative | J9AccAbstract, method1->modifiers)) {
/* Walk the bytecodes in parallel looking for mismatches */
bytecodes1 = J9_BYTECODE_START_FROM_ROM_METHOD(method1);
romCP1 = J9_ROM_CP_FROM_ROM_CLASS(romClass1);
bytecodes2 = J9_BYTECODE_START_FROM_ROM_METHOD(method2);
romCP2 = J9_ROM_CP_FROM_ROM_CLASS(romClass2);
index = 0;
while (index < size) {
U_8 bc = bytecodes1[index];
UDATA bytecodeSize;
UDATA alreadyCompared;
U_8 bc2 = bytecodes2[index];
/* Bytecode numbers/indices in each method must be identical */
if (bc != bc2) {
/* Treat all return instructions to JBgenericReturn */
if (RTV_RETURN == (J9JavaBytecodeVerificationTable[bc] >> 8)) {
bc = JBgenericReturn;
}
if (RTV_RETURN == (J9JavaBytecodeVerificationTable[bc2] >> 8)) {
bc2 = JBgenericReturn;
}
if (bc != bc2) {
return FALSE;
}
}
alreadyCompared = 1;
bytecodeSize = J9JavaInstructionSizeAndBranchActionTable[bc] & 7;
switch (bc) {
case JBcheckcast:
case JBinstanceof:
case JBmultianewarray:
case JBnew:
case JBanewarray:
if (!areClassRefsIdentical(romCP1, NEXT_U16(bytecodes1), romCP2, NEXT_U16(bytecodes2))) {
return FALSE;
}
alreadyCompared += 2;
break;
case JBinvokeinterface2:
alreadyCompared += 2;
/* Intentional fall-through */
case JBinvokespecial:
case JBinvokestatic:
case JBinvokespecialsplit:
case JBinvokestaticsplit:
case JBinvokevirtual: {
U_16 cpIndex1 = NEXT_U16(bytecodes1);
U_16 cpIndex2 = NEXT_U16(bytecodes2);
if (JBinvokestaticsplit == bc) {
/* use cpIndex1 as index into slit table */
cpIndex1 = *(U_16 *)(J9ROMCLASS_STATICSPLITMETHODREFINDEXES(romClass1) + cpIndex1);
} else if (JBinvokespecialsplit == bc) {
/* use cpIndex1 as index into slit table */
cpIndex1 = *(U_16 *)(J9ROMCLASS_SPECIALSPLITMETHODREFINDEXES(romClass1) + cpIndex1);
}
if (JBinvokestaticsplit == bc2) {
/* use cpIndex2 as index into slit table */
cpIndex2 = *(U_16 *)(J9ROMCLASS_STATICSPLITMETHODREFINDEXES(romClass2) + cpIndex2);
} else if (JBinvokespecialsplit == bc) {
/* use cpIndex2 as index into slit table */
cpIndex2 = *(U_16 *)(J9ROMCLASS_SPECIALSPLITMETHODREFINDEXES(romClass2) + cpIndex2);
}
if (!areMethodRefsIdentical(romCP1, cpIndex1, romCP2, cpIndex2)) {
return FALSE;
}
alreadyCompared += 2;
break;
}
case JBgetfield:
case JBputfield:
case JBgetstatic:
case JBputstatic:
if (!areFieldRefsIdentical(romCP1, NEXT_U16(bytecodes1), romCP2, NEXT_U16(bytecodes2))) {
return FALSE;
}
alreadyCompared += 2;
break;
case JBldc:
if (!areSingleSlotConstantRefsIdentical(romCP1, bytecodes1[index + alreadyCompared], romCP2, bytecodes2[index + alreadyCompared])) {
return FALSE;
}
alreadyCompared += 1;
break;
case JBldcw:
if (!areSingleSlotConstantRefsIdentical(romCP1, NEXT_U16(bytecodes1), romCP2, NEXT_U16(bytecodes2))) {
return FALSE;
}
alreadyCompared += 2;
break;
case JBldc2dw:
case JBldc2lw:
if (!areDoubleSlotConstantRefsIdentical(romCP1, NEXT_U16(bytecodes1), romCP2, NEXT_U16(bytecodes2))) {
return FALSE;
}
alreadyCompared += 2;
break;
case JBlookupswitch:
case JBtableswitch: {
UDATA tempIndex = index + (4 - (index & 3));
UDATA numEntries;
I_32 low;
tempIndex += 4;
low = *((I_32 *) (bytecodes1 + tempIndex));
tempIndex += 4;
if (bc == JBtableswitch) {
I_32 high = *((I_32 *) (bytecodes1 + tempIndex));
tempIndex += 4;
numEntries = (UDATA) (high - low + 1);
} else {
numEntries = ((UDATA) low) * 2;
}
bytecodeSize = (tempIndex + (4 * numEntries)) - index;
break;
}
}
/* Compare any remaining bytes that have not been treated */
if (memcmp(bytecodes1 + index + alreadyCompared, bytecodes2 + index + alreadyCompared, bytecodeSize - alreadyCompared) != 0) {
return FALSE;
}
index += bytecodeSize;
}
}
return TRUE;
#undef NEXT_U16
}
void
fixSubclassHierarchy(J9VMThread * currentThread, J9HashTable * classPairs)
{
J9JavaVM * vm = currentThread->javaVM;
PORT_ACCESS_FROM_JAVAVM(vm);
J9HashTableState hashTableState;
J9JVMTIClassPair * classPair;
J9JVMTIClassPair ** array;
J9JVMTIClassPair exemplar;
J9JVMTIClassPair * result;
UDATA classCount;
UDATA i;
/*
* Remove all replaced classes from the subclass traversal list.
*/
classPair = hashTableStartDo(classPairs, &hashTableState);
while (classPair != NULL) {
removeFromSubclassHierarchy(vm, classPair->originalRAMClass);
classPair = hashTableNextDo(&hashTableState);
}
/* copy the pairs in the hashTable into an array so that they may be sorted */
classCount = hashTableGetCount(classPairs);
array = j9mem_allocate_memory(classCount * sizeof(*array), OMRMEM_CATEGORY_VM);
if (array == NULL) {
return;
}
classPair = hashTableStartDo(classPairs, &hashTableState);
for (i = 0; i < classCount; ++i) {
array[i] = classPair;
classPair = hashTableNextDo(&hashTableState);
}
/* sort the array so that superclasses appear before subclasses */
J9_SORT(array, (UDATA)classCount, sizeof(J9JVMTIClassPair*), compareClassDepth);
/* Add all the new classes to the graph */
for (i = 0; i < classCount; ++i) {
J9Class * replacementClass;
J9Class * superclass;
J9Class * nextLink;
UDATA superclassCount = 0;
if (array[i]->replacementClass.ramClass) {
replacementClass = array[i]->replacementClass.ramClass;
} else {
replacementClass = array[i]->originalRAMClass;
}
superclass = GET_SUPERCLASS(replacementClass);
/* Find the correct superclass. If the superclass of replacementClass
* was replaced itself, make sure we use the new superclass
*/
exemplar.originalRAMClass = superclass;
result = hashTableFind(classPairs, &exemplar);
if (NULL != result) {
if (NULL != result->replacementClass.ramClass) {
/* we found the original superclass inside the old-new
* mapping table and have determined a new RAM class
* was created. we should use the new superclass's RAM class
* from now on to fix up any possible reference to this class.
*/
superclass = result->replacementClass.ramClass;
}
}
/* Update classes->superclass array with possibly updated ramClass address */
superclassCount = J9CLASS_DEPTH(superclass);
memcpy(replacementClass->superclasses, superclass->superclasses, superclassCount * sizeof(UDATA));
replacementClass->superclasses[superclassCount] = superclass;
/*
printf("super [j9class %p -> %p] <- class [j9class %p]\n",
superclass, superclass->subclassTraversalLink, replacementClass);
*/
nextLink = superclass->subclassTraversalLink;
replacementClass->subclassTraversalLink = nextLink;
nextLink->subclassTraversalReverseLink = replacementClass;
superclass->subclassTraversalLink = replacementClass;
replacementClass->subclassTraversalReverseLink = superclass;
}
}
/*
* Examine the class stored in classSlot to determine if it has
* been replaced. If it has, store the replacement class into
* classSlot
*/
static void
fixClassSlot(J9VMThread* currentThread, J9Class** classSlot, J9HashTable *classPairs)
{
J9JVMTIClassPair exemplar;
J9JVMTIClassPair* result;
exemplar.originalRAMClass = *classSlot;
result = hashTableFind(classPairs, &exemplar);
if (result != NULL) {
/* replace the class slot only if we have a replacement class */
if (result->replacementClass.ramClass) {
*classSlot = result->replacementClass.ramClass;
}
}
}
/*
* For each replaced interface in classPairs, update the iTables of
* all implementors to point at the new version of the class.
*/
void
fixITables(J9VMThread * currentThread, J9HashTable * classPairs)
{
J9HashTableState hashTableState;
J9JVMTIClassPair * classPair;
UDATA anyInterfaces = FALSE;
J9JavaVM* vm = currentThread->javaVM;
J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
J9Class* clazz;
J9ClassWalkState classWalkState;
/* first determine if any interfaces have been replaced */
classPair = hashTableStartDo(classPairs, &hashTableState);
while (classPair != NULL) {
J9Class * originalRAMClass = classPair->originalRAMClass;
if (originalRAMClass->romClass->modifiers & J9AccInterface) {
anyInterfaces = TRUE;
break;
}
classPair = hashTableNextDo(&hashTableState);
}
clazz = vmFuncs->allClassesStartDo(&classWalkState, vm, NULL);
while (clazz != NULL) {
if (anyInterfaces) {
J9ITable *iTable = (J9ITable *)clazz->iTable;
while( iTable != NULL ) {
fixClassSlot(currentThread, &iTable->interfaceClass, classPairs);
iTable = iTable->next;
}
}
if (J9_IS_CLASS_OBSOLETE(clazz)) {
fixClassSlot(currentThread, &clazz->arrayClass, classPairs);
}
clazz = vmFuncs->allClassesNextDo(&classWalkState);
}
vmFuncs->allClassesEndDo(&classWalkState);
/* Iterate through replaced classes and their subclasses
* - if the class has an iTable defined in a replaced class
* change it to the newest version of the iTable
*/
classPair = hashTableStartDo(classPairs, &hashTableState);
while (classPair != NULL) {
if (classPair->replacementClass.ramClass == NULL) {
clazz = classPair->originalRAMClass;
} else {
clazz = classPair->replacementClass.ramClass;
}
clazz->lastITable = (J9ITable *) &invalidITable;
if (clazz->iTable) {
J9Class * superClass = GET_SUPERCLASS(clazz);
J9JVMTIClassPair * result;
J9JVMTIClassPair exemplar;
/* Look at the superclass of clazz in the hashtable
* - if the superclass was replaced
* - change any iTable structures in clazz to the one from the
* new superclass version
*/
while (superClass) {
exemplar.originalRAMClass = superClass;
result = hashTableFind(classPairs, &exemplar);
if (NULL != result) {
if (result->replacementClass.ramClass) {
/* Get the iTable of the replaced superclass */
J9ITable * oldSuperITable = (J9ITable *) result->originalRAMClass->iTable;
/* See if the old iTable is used as head of the clazz iTable list and
* replace it with the new iTable version. Otherwise keep looking by
* following the iTable linked list */
if (((J9ITable *) clazz->iTable) == oldSuperITable) {
clazz->iTable = result->replacementClass.ramClass->iTable;
} else {
J9ITable * iTable = (J9ITable *) clazz->iTable;
while (iTable != NULL) {
if (iTable->next == oldSuperITable) {
iTable->next = (J9ITable *) result->replacementClass.ramClass->iTable;
}
iTable = iTable->next;
}
}
}
}
superClass = GET_SUPERCLASS(superClass);
}
}
classPair = hashTableNextDo(&hashTableState);
}
/* Find all obsolete classes and make sure they have their iTable pointing at the newest
version. This covers a scenario where we have the following class hierarchy:
C1 implements I1
C2 extends C1
C3 extends C2
Assume C2 and C3 have been replaced at least once and we are currently replacing C1.
We need to walk all old versions of C2 and C3 and replace their class->iTables with the
one from the most current version (but only once it itself has been fixed). Failure
to do so will cause MM_MarkingScheme::scanClass to fall off the end of its iTables
walk while scanning an old class version
CMVC 153732: Fast HCR Doesn't Share Superclass' ITable */
/* TODO: We need to come up with another unused field in obsolete J9Classes to maintain
a chain of back references through all obsolete versions of a given class that terminates
at the oldest version. This class walk will then change to a classPairs hashtable walk
of the whole redefined hierarchy fixing up itables of all obsolete classes using the reverse
obsolete class chain */
clazz = vmFuncs->allClassesStartDo(&classWalkState, vm, NULL);
while (clazz != NULL) {
if (J9_IS_CLASS_OBSOLETE(clazz)) {
clazz->iTable = J9_CURRENT_CLASS(clazz)->iTable;
}
clazz = vmFuncs->allClassesNextDo(&classWalkState);
}
vmFuncs->allClassesEndDo(&classWalkState);
return;
}
static UDATA
findMethodInVTable(J9Method *method, UDATA *vTable)
{
J9ROMMethod *romMethod = J9_ROM_METHOD_FROM_RAM_METHOD(method);
J9VTableHeader *vTableHeader = (J9VTableHeader *)vTable;
J9Method **vTableMethods = J9VTABLE_FROM_HEADER(vTableHeader);
UDATA vTableSize = vTableHeader->size;
UDATA searchIndex = 0;
/* Search the vTable for a public method of the correct name. */
for (searchIndex = 0; searchIndex < vTableSize; searchIndex++) {
J9Method *vTableMethod = vTableMethods[searchIndex];
J9ROMMethod *vTableRomMethod = J9_ROM_METHOD_FROM_RAM_METHOD(vTableMethod);
if (vTableRomMethod->modifiers & J9_JAVA_PUBLIC) {
if (J9ROMMETHOD_NAME_AND_SIG_IDENTICAL(J9_CLASS_FROM_METHOD(method)->romClass, J9_CLASS_FROM_METHOD(vTableRomMethod)->romClass, romMethod, vTableRomMethod)) {
return searchIndex;
}
}
}
return (UDATA)-1;
}
void
fixITablesForFastHCR(J9VMThread *currentThread, J9HashTable *classPairs)
{
J9JVMTIClassPair *classPair;
J9HashTableState hashTableState;
UDATA updateITables = FALSE;
/* This is only necessary if methods were re-ordered in an interface update. */
classPair = hashTableStartDo(classPairs, &hashTableState);
while (NULL != classPair) {
J9ROMClass *romClass = classPair->originalRAMClass->romClass;
if ((0 != (romClass->modifiers & J9AccInterface)) && (NULL != classPair->methodRemap)) {
updateITables = TRUE;
break;
}
classPair = hashTableNextDo(&hashTableState);
}
if (updateITables) {
J9JavaVM *vm = currentThread->javaVM;
J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
J9Class *clazz;
J9ClassWalkState classWalkState;
clazz = vmFuncs->allClassesStartDo(&classWalkState, vm, NULL);
while (NULL != clazz) {
if (!J9_IS_CLASS_OBSOLETE(clazz) && (0 == (clazz->romClass->modifiers & J9AccInterface))) {
J9ITable *iTable = (J9ITable *)clazz->iTable;
J9ITable *superITable = NULL;
UDATA classDepth = J9CLASS_DEPTH(clazz);
if (0 != classDepth) {
superITable = (J9ITable *) GET_SUPERCLASS(clazz)->iTable;
}
while (superITable != iTable) {
J9ITable *allInterfaces = (J9ITable*)iTable->interfaceClass->iTable;
UDATA *iTableMethods = (UDATA *)(iTable + 1);
do {
J9Class *interfaceClass = allInterfaces->interfaceClass;
J9JVMTIClassPair exemplar;
J9JVMTIClassPair *result;
UDATA methodCount = interfaceClass->romClass->romMethodCount;