gnu.jel.ClassFile Maven / Gradle / Ivy
/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* $Id: ClassFile.java 490 2006-10-01 16:08:04Z metlov $
*
* This file is part of the Java Expressions Library (JEL).
* For more information about JEL visit :
* http://kinetic.ac.donetsk.ua/JEL/
*
* (c) 1998 -- 2007 by Konstantin Metlov([email protected]);
*
* JEL is Distributed under the terms of GNU General Public License.
* This code comes with ABSOLUTELY NO WARRANTY.
* For license details see COPYING file in this directory.
*/
package gnu.jel;
import gnu.jel.debug.Debug;
import java.lang.reflect.Member;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Constructor;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Stack;
import java.util.Vector;
/**
* This class represents a classfile image in JEL.
*/
public class ClassFile implements Cloneable {
// constant pool handling
private int poolEntries=1; // Number of entries in the constant pool
// the class name is in the first element of the CP
// it is not written by default to enable the dynamic class renaming.
private ByteArrayOutputStream constPoolData;
private DataOutputStream constPool;
// Constant pool hashing :
// In next hashtables keys are Objects, values their CP indices
// UTFs require special handling since their keys can be the same as
// ones of strings
private HashMap Items=new HashMap();
private HashMap UTFs=new HashMap();
// holds code of all methods
private int nMethods=0;
private int nMethodsPatch;
// holds code of all methods
private byte[] text;
int tsize=0;
// write a byte
void write(int b) {
try {
text[tsize++]=(byte)b;
} catch (ArrayIndexOutOfBoundsException exc) {
byte[] new_text=new byte[text.length<<1];
System.arraycopy(text, 0, new_text, 0, tsize-1);
text=new_text;
text[tsize-1]=(byte)b;
};
};
// write short
void writeShort(int v) {
write((v >>> 8) & 0xFF);
write( v & 0xFF);
};
// write int
void writeInt(int v) {
write((v >>> 24) & 0xFF);
write((v >>> 16) & 0xFF);
write((v >>> 8) & 0xFF);
write( v & 0xFF);
};
private boolean isInterface;
private IntegerStack[] cstk=new IntegerStack[6];
// six stacks
// 0) "false" jumps
// 1) "true" jumps
// 2) unconditional jumps
// 3) "false" blocks
// 4) "true" blocks
// 6) unconditional blocks
/**
* Starts creation of a new class file.
* Sizes of fAccess, fNames and fTypes
* arrays must be the same.
* @param modifiers sum of one or more of PUBLIC, FINAL,
* INTERFACE, ABSTRACT
* constants of java.lang.reflect.Modifier
* @param name is the name of new class (must be in Java historical form,
* i.e. with dots replaced by slashes '/')
* @param superClass is the superclass of this class
* @param interfaces array of interfaces this class implements
* @param fields fields this class will have
*/
public ClassFile(int modifiers,String name,Class superClass,
Class[] interfaces,LocalField[] fields) {
constPoolData=new ByteArrayOutputStream();
constPool=new DataOutputStream(constPoolData);
text=new byte[256];
if (Debug.enabled)
Debug.check(cstk.length==6);
for (int i=0;i<6;i++)
cstk[i]=new IntegerStack();
try {
if (Debug.enabled) // check if the name is in historical form
Debug.check(name.indexOf('.')==-1);
getUTFIndex(name); // must be the first entry
if (Debug.enabled)
Debug.check((modifiers & ~(java.lang.reflect.Modifier.PUBLIC+
java.lang.reflect.Modifier.FINAL+
java.lang.reflect.Modifier.INTERFACE+
java.lang.reflect.Modifier.ABSTRACT))==0);
isInterface=((modifiers & 0x0200)>0);
// write modifiers
writeShort(modifiers | 0x0020); // set ACC_SUPER flag
// CONSTANT_CLASS for a new class, has to be written by hand
// since no corresponding java.lang.Class object exists yet.
if (Debug.enabled)
Debug.check(poolEntries==2);
poolEntries++;
constPool.write(7);
constPool.writeShort(1); //name of this class is always the first entry.
// write class cp index
writeShort(2);
// write superclass cp index
writeShort(getIndex(superClass,9));
// write out interfaces
int nInterfaces;
if (interfaces==null) nInterfaces=0; else nInterfaces=interfaces.length;
writeShort(nInterfaces);
for(int i=0;i This is used in JEL to avoid step-by step creation of service
* methods of gnu.jel.CompiledExpression (, getType, ...). They are
* created only once, and then the resulting ClassFile is cloned
* at the point, when it is ready to accept the code for evaluation method.
* @return a clone of this object
*/
public ClassFile clone() {
ClassFile res=null;
try {
res=(ClassFile)super.clone(); // clone all primitive members
// clone containers
res.Items=new HashMap(res.Items);
res.UTFs=new HashMap(res.UTFs);
res.paramsVars=(int [])res.paramsVars.clone();
res.branchStack=res.branchStack.copy();
if (Debug.enabled)
Debug.check(cstk.length==6);
res.cstk=new IntegerStack[6];
for(int i=0;i<6;i++)
res.cstk[i]=cstk[i].copy();
// clone streams
res.constPoolData=new ByteArrayOutputStream();
constPool.flush();
constPoolData.writeTo(res.constPoolData);
res.constPool=new DataOutputStream(res.constPoolData);
res.text=(byte[]) res.text.clone();
} catch (IOException exc) {
if (Debug.enabled)
Debug.reportThrowable(exc);
} catch (CloneNotSupportedException exc) {
if (Debug.enabled)
Debug.reportThrowable(exc);
};
return res;
};
private int startCodeAttr=0;
private int startCode=0;
/**
* Starts a new method of this class.
* @param m method descriptor.
* @param vars types of local variables by number.
*/
public void newMethod(LocalMethod m, Class[] vars) {
if (Debug.enabled) {
Debug.check(cW==0);
for(int i=0;i<6;i++)
Debug.check(cstk[i].size()==0);
Debug.check(currJump==0);
};
// first finish the last method
finishMethod();
nMethods++;
// now prepare creation of a new one.
int mdfrs=m.getModifiers();
if (isInterface) mdfrs=mdfrs | 0x0400; // mark abstract for interfaces
boolean isAbstract=((mdfrs & 0x0400) > 0);
writeShort(mdfrs); // modifiers
writeShort(getUTFIndex(m.getName())); // name index
writeShort(getUTFIndex(Library.getSignature(m))); // signature index
int temp=0;
Class[] exceptions=m.getExceptionTypes();
if (exceptions!=null) temp++; // exceptions are in separate attribute
if (!isAbstract) temp++; // non-abstract methods have code
writeShort(temp);
// first we write exceptions attribute, if needed
if (exceptions!=null) {
temp=exceptions.length;
writeShort(getUTFIndex("Exceptions"));
writeInt((temp+1)*2); // attribute length
writeShort(temp);
for(int i=0;i>> 8) & 0xFF);
image.write((poolEntries >>> 0) & 0xFF);
constPoolData.writeTo(image);
image.write(text,0,tsize);
image.write(0); // no class file attributes
image.write(0); // no class file attributes
} catch (IOException exc) {
// can't be
};
return image.toByteArray();
};
//=========================================================
//========== INSTRUCTIONS INTERFACE TO THE STATE===========
//=========================================================
private LocalMethod currMethod=null;
int[] paramsVars=null; // correspondence between parameter number and lvars.
// current, and maximum number of words in Java stack
private int cW=0, mW=0;
/** Notes removal of typeID s and subsequent addition of typeID a
* to Java stack.
* If either is negative the corresponding operation
* (addition/removal) is skipped. This method is needed to allow ClassFile
* to compute the maximum stack occupation for the generated code. It is
* responsibility of the user (of this class) to call noteStk() each
* time the stack is changed from within the code.
* @param s typeid to be put on stack (-1 if none).
* @param a typeid to be taken off Java stack (-1 if none).
*/
public void noteStk(int s,int a) {
if (Debug.enabled)
Debug.check(cW<=mW);
if ((s>=0) && (s!=9)) {
cW--;
if ((s & (~2)) == 5) cW--; // Note additional word for J and D
if (Debug.enabled)
Debug.check(cW>=0);
};
if ((a>=0) && (a!=9)) {
cW++;
if ((a & (~2)) == 5) cW++; // Note additional word for J and D
if (cW>mW) mW=cW;
};
};
/**
* classes frequently used in generated code
*/
private static final Class[] specialClasses;
static {
if (Debug.enabled)
Debug.check(OP.specialTypes.length==29,
"You changed special types in TypesStack please update "+
"specialClasses array in ClassFile.");
specialClasses=(Class[])TableKeeper.getTable("specialClasses");
};
private static final Member[] specialMethods;
static {
char[][] specialMds=(char[][]) TableKeeper.getTable("specialMds");
String[] specialMdsN=(String[]) TableKeeper.getTable("specialMdsN");
specialMethods=new Member[specialMds.length];
{
Class definingClass=null;
String name=null;
Class[] params=null;
int i=0;
try {
for (i=0;i=beforeStk);
};
// remove the result of the previous branch, the other branch must
// put the same thing back into the types stack
cW=beforeStk;
code(0xEDECF2A7L);
//| A7 -- goto
//| F2 -- make down pointing unconditional label
//| EC -- block unconditional labels
//| ED -- land unblocked "false" labels
break;
case 2: // opc=230 (0xE6) -- finish "false" branch
if (Debug.enabled) {
code(0xFA);
// FA -- ensure_value();
Debug.check((branchStack.pop()==cW),
"Stack mismatch when compiling conditional");
code(0xEFE9);
// E9 -- unblock unconditional jumps
// EF -- land unblocked unconditional labels
} else {
code(0xEFE9FA);
// FA -- ensure_value();
// E9 -- unblock unconditional jumps
// EF -- land unblocked unconditional labels
};
break;
case 3: // opc=231 (0xE7) -- unblock "false" labels
case 4: // opc=232 (0xE8) -- unblock "true" labels
case 5: // opc=233 (0xE9) -- unblock unconditional labels
cstk[opc-(mc+3-3)].pop();
break;
case 6: // opc=234 (0xEA) -- block "false" labels
case 7: // opc=235 (0xEB) -- block "true" labels
case 8: // opc=236 (0xEC) -- block unconditional labels
cstk[opc-(mc+6-3)].push(cstk[opc-(mc+6)].size());
break;
case 9: // opc=237 (0xED) -- land unblocked "false" labels
case 10: // opc=238 (0xEE) -- land unblocked "true" labels
case 11: // opc=239 (0xEF) -- land unblocked unconditional labels
{
int blocked_at=0;
final IntegerStack blk=cstk[opc-(mc+9-3)];
final IntegerStack jmp=cstk[opc-(mc+9 )];
if (blk.size()>0) blocked_at=blk.peek();
while (jmp.size()>blocked_at) {
int currpos=tsize;
int addrpos=jmp.pop();
// in the next command -1 because displacement is counted from the
// jump opcode
tsize=addrpos;
writeShort(currpos-addrpos+1);
tsize=currpos;
};
};
break;
case 12: // opc=240 (0xF0) -- make down pointing "false" label (j0)
case 13: // opc=241 (0xF1) -- make down pointing "true" label (j1)
case 14: // opc=242 (0xF2) -- make down pointing unconditional label
cstk[opc-(mc+12 )].push(tsize);
writeShort(0); // placeholder for the backpatched address
break;
case 15: // opc=243 (0xF3) -- set current open jump (code in next byte)
currJump=(int)((op=op>>>8) & 0xFF);
break;
case 16: // opc=244 (0xF4) -- logical param AND
case 17: // opc=245 (0xF5) -- logical param OR
{
// for AND s=0 for OR s=1
int s=(opc-(mc+16));
code(0xF9); // ensure jump
if (iNJ ^ (s==0)) {
if (Debug.enabled)
Debug.check((currJump>=153) && (currJump<=166),
"Attempt to invert non jump bytecode ("+
currJump+")");
currJump=(((currJump-1) ^ 0x0001)+1);
};
iNJ=false;
code(0x00F300+currJump);
// 00F3 -- set curr jump to 0
code((0xEAEDF0) + (s<<16)+((s^1)<<8)+s);
// code is
// F0 - make label j0 modified by s
// ED - land labels j1 modified by s^1
// EA - block labels j0 modified by s
};
break;
case 18: // opc=246 (0xF6) -- logical end AND
case 19: // opc=247 (0xF7) -- logical end OR
cstk[opc-(mc+18-3)].pop(); // just throw the corresponding block
break;
case 20: // opc 248 (0xF8) -- unblock all labels
code(0xE7E8E9);
break;
case 21: // opc=249 (0xF9) -- ensure jump is in progress
if (currJump==0) {
// if no jump in progress yet
noteStk(0,-1); // "boolean" is removed from stack
currJump=157; //|
};
break;
case 22: // opc=250 (0xFA) -- ensure value is in stack
boolean noPendingJumps=false;
if (currJump==0) {
// check if there are pending jumps
int blocked0=0;
if (cstk[3].size()>0) blocked0=cstk[3].peek();
int blocked1=0;
if (cstk[4].size()>0) blocked1=cstk[4].peek();
noPendingJumps=(cstk[0].size()==blocked0) &&
(cstk[1].size()==blocked1);
};
if (!noPendingJumps) {
// if there are pending jumps or jump in progress
code(0xE4); // branch_true();
codeLDC(Boolean.TRUE,0);
code(0xE5); // branch_false();
codeLDC(Boolean.FALSE,0);
code(0xE6); // branch_end();
};
break;
case 23: // opc=251 (0xFB) -- block labels
code(0xEAEBEC);
break;
case 24: // opc==252 (0xFC) -- unblock labels with inversion
code(0xF9); // ensure jump
IntegerStack.swap(cstk[1],cstk[4].pop(),cstk[0],cstk[3].pop());
cstk[5].pop();
iNJ=!iNJ;
break;
case 25: // opc==253 (0xFD) -- write special class CP ref
op=op >>> 8;
writeShort(getIndex(specialClasses[(int)(op & 0xFFL)],9));
break;
case 26: // opc==254 (0xFE) -- call special method
op=op >>> 8;
codeM(specialMethods[(int)(op & 0xFF)]);
break;
default:
if (Debug.enabled)
Debug.check(opc !=0xFF);
write(opc);
};
op=op >>> 8;
};
};
// Shortcut load opcodes for int type
// index is value+1; allowed values from -1 to 5.
// other values should be loaded from CP.
// private final static int[] load_ints=
// { 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
// -1 0 1 2 3 4 5
// private final static int[] load_long_ints=
// {0x8502, 0x09, 0x0A,0x8505,0x8506,0x8507,0x8508};
// -1 0 1 2 3 4 5
/**
* generates code for code loading constant of primitive type or string.
* @param o reflection object or String containing the constant
* @param primitiveID type ID to save lookups.
*/
public final void codeLDC(Object o, int primitiveID) {
if (Debug.enabled)
Debug.check(((primitiveID>=0) && (primitiveID<8)) ||
((primitiveID==8) && (o==null)) ||
((primitiveID==10) && (o instanceof StringBuffer)) ||
((primitiveID==11) && (o instanceof String)));
int short_opcodes=0;
boolean tsb_store=false;
int iv=-1;
switch (primitiveID) {
case 0:
iv=(((Boolean)o).booleanValue()?1:0);
case 2:
if (iv<0) iv=(int)((Character)o).charValue();
case 1:
case 3:
case 4:
if (iv<0) iv=((Number)o).intValue();
if ((iv>=-1) && (iv<=5))
short_opcodes=iv+3; //| iconst_
else if ((iv>=-128) && (iv<=127))
short_opcodes=0x00000010 | ((iv & 0xFF)<<8); //| bipush,
break;
case 5:
long lv=((Long)o).longValue();
if (((lv | 1)^1) == 0) { // 0 or 1
short_opcodes=0x09+(int)lv;
} else if ((lv>=-1) && (lv<=5)) {
short_opcodes=0x8503+(int)lv;
};
break;
case 6:
float fv=((Float)o).floatValue();
if (fv==0.0f) short_opcodes=0x0B; //| fconst_0
else if (fv==1.0f) short_opcodes=0x0C; //| fconst_1
else if (fv==2.0f) short_opcodes=0x0D; //| fconst_2
break;
case 7:
double dv=((Double)o).doubleValue();
if (dv==0.0) short_opcodes=0x0E; //| dconst_0
else if (dv==1.0) short_opcodes=0x0F; //| dconst_1
break;
case 8:
if (o==null) short_opcodes=0x01; //| aconst_null
break;
case 10:
tsb_store=true;
case 11:
short_opcodes=0;
primitiveID=8;
break;
default:
if (Debug.enabled)
Debug.check(false,"Loading of object constants is not supported by "+
"the Java class files.");
};
if (short_opcodes==0) {
// longs and doubles occupy two elements of stack all others just one
boolean dword_const=((primitiveID==5) || (primitiveID==7));
int cpindex;
if (tsb_store) {
code(0x0001FE591DFDBBL); // STR => TSB
// | new
//
// | dup
// | invokespecial StringBuffer()
noteStk(-1,10); // pushes ref to TSB
cpindex=getIndex(o.toString(),primitiveID);
} else {
// makes use of the fact that primitiveID(Object)==typeID(string)
cpindex=getIndex(o,primitiveID);
};
if (Debug.enabled)
Debug.check((cpindex>=0) && (cpindex<=65535));
if ((!dword_const) && (cpindex<=255)) {
write(0x12); //| ldc
write(cpindex);
} else {
int opc=0x13; //| ldc_w
if (dword_const) opc++; //| ldc2_w
write(opc);
writeShort(cpindex);
};
} else {
codeB(short_opcodes);
}
noteStk(-1,primitiveID); // add what was loaded
if (tsb_store) {
code(0x08FE);
noteStk(11,-1); // remove extra string used up by constructor
};
};
//=========================================================
//================= CONSTANTS POOL HANDLING ===============
//=========================================================
/**
* Used to get the index of the given UTF8 string in the Constant Pool.
* If the specified string was not found in the pool -- it is added.
* @param str the string to look for ( to add )
* @return index of the string in the Constant Pool.
*/
int getUTFIndex(String str) {
// Check if it is in the pool already
Integer index=UTFs.get(str);
if (index==null) { // add UTF to the pool
index=new Integer(poolEntries++);
try {
constPool.write(1); // CONSTANT_Utf8 = 1;
constPool.writeUTF(str);
} catch (java.io.IOException e) {
if (Debug.enabled) Debug.reportThrowable(e);
};
UTFs.put(str,index);
};
return index.intValue();
};
// encodes types of relevant objects as integers
// for classes corresponding to primitive types codes are the same as
// primitiveID's
private int typeID(Object item) {
int id=OP.typeIDObject(item);
if (id<8) return id;
if (item instanceof String) return 8;
if (item instanceof Class) return 9;
if (item instanceof Member) return 10;
return -1;
};
/**
* Used to determine an old CP index or to create a new one for an item.
* @param item an item to create or get an index for
* @return index for an item (negative if it has to be written)
*/
private final int getIndex(Object item) {
return getIndex(item,typeID(item));
};
/**
* Used to determine an old CP index or to create a new one for an item.
* @param item an item to create or get an index for
* @param typeid identifies type of argument to avoid linear searches
* @return index for an item (negative if it has to be written)
*/
public int getIndex(Object item,int typeid) {
Integer index=Items.get(item);
if (index==null) {
int newIndex=-1;
try {
int ival=-1;
switch (typeid) {
case 0:
ival=((Boolean)item).booleanValue()?1:0;
case 2:
if (ival<0) ival=(int)((Character)item).charValue();
case 1:
case 3:
case 4:
if (ival<0) ival=((Number)item).intValue();
newIndex=poolEntries++;
constPool.write(3); // CONSTANT_Integer = 3;
constPool.writeInt(ival);
break;
case 5:
newIndex=poolEntries;
constPool.write(5); // CONSTANT_Long = 5;
constPool.writeLong(((Long)item).longValue());
poolEntries+=2; // Long occupies two entries in CP, weird !!!
break;
case 6:
newIndex=poolEntries++;
constPool.write(4); // CONSTANT_Float = 4;
constPool.writeFloat(((Float)item).floatValue());
break;
case 7:
newIndex=poolEntries;
constPool.write(6); // CONSTANT_Double = 6;
constPool.writeDouble(((Double)item).doubleValue());
poolEntries+=2; // Double occupies two entries in CP, weird !!!
break;
case 8:
{
int UTFIndex=getUTFIndex((String)item); // write string , if needed
newIndex=poolEntries++;
constPool.write(8); // CONSTANT_String = 8;
constPool.writeShort(UTFIndex);
}
break;
case 9:
{
String histNameStr=
Library.toHistoricalForm(((Class)item).getName());
int UTFIndex=getUTFIndex(histNameStr); // write FQCN , if needed
newIndex=poolEntries++;
constPool.write(7); // CONSTANT_Class = 7;
constPool.writeShort(UTFIndex);
}
break;
case 10: // Method
case 11: // Constructor
case 12: // Field
Member member = (Member) item;
Class dClass=member.getDeclaringClass();
int entryType;
if (Library.isField(member))
entryType=9; // CONSTANT_Fieldref = 9;
else if ((dClass!=null) && (dClass.isInterface()))
entryType=11; // CONSTANT_InterfaceMethodref = 11;
else
entryType=10; // CONSTANT_Methodref = 10;
newIndex=writeMemberRef(member,entryType);
break;
default:
if (Debug.enabled)
Debug.println("Can't place an item of type \""+
item.getClass().getName()+
"\" to the constant pool.");
};
} catch (java.io.IOException e) {
if (Debug.enabled) Debug.reportThrowable(e);
};
index=new Integer(newIndex);
Items.put(item,index);
};
return index.intValue();
};
// writes out full reference to method, interface or field
// this includes UTFs, Name&Type and XXX_ref entries
private int writeMemberRef(Member member, int entry)
throws java.io.IOException {
if (Debug.enabled)
Debug.check((entry==10)||(entry==9)||(entry==11));
// CONSTANT_Fieldref = 9; CONSTANT_Methodref = 10;
// CONSTANT_InterfaceMethodref = 11;
int name_ind=getUTFIndex((member instanceof Constructor)?"":
member.getName());
int sign_ind=getUTFIndex(Library.getSignature(member));
Class dClass=member.getDeclaringClass();
int cls_ind;
if (dClass==null) cls_ind=2; else cls_ind=getIndex(dClass,9);
// this class ---^^^^^^^^^ 9 means Class--^
// Create Name and Type record
int nat_ind=poolEntries++;
constPool.write(12); // CONSTANT_NameAndType = 12;
constPool.writeShort(name_ind);
constPool.writeShort(sign_ind);
// Create XXX_ref entry (where XXX is InterfaceMethod, Method or field)
int index=poolEntries++;
constPool.write(entry);
constPool.writeShort(cls_ind);
constPool.writeShort(nat_ind);
return index;
};
//================================================================
//================== END OF CONSTANT POOL HANDLING ===============
//================================================================
};