import java.io.*;
import java.util.*;
+/** A class representing a method in a generated classfile
+ @see ClassGen#addMethod */
public class MethodGen implements CGConst {
private final static boolean EMIT_NOPS = false;
private byte[] op;
private Object[] arg;
+ MethodGen(DataInput in) { throw new Error("Brian is lame"); }
MethodGen(ClassGen owner, String name, Type ret, Type[] args, int flags) {
if((flags & ~(ACC_PUBLIC|ACC_PRIVATE|ACC_PROTECTED|ACC_STATIC|ACC_FINAL|ACC_SYNCHRONIZED|ACC_NATIVE|ACC_ABSTRACT|ACC_STRICT)) != 0)
throw new IllegalArgumentException("invalid flags");
if((owner.flags & ACC_INTERFACE) != 0 || (flags & (ACC_ABSTRACT|ACC_NATIVE)) != 0) size = capacity = -1;
- maxLocals = Math.max(args.length + (flags&ACC_STATIC)==0 ? 1 : 0,4);
+ maxLocals = Math.max(args.length + (flags&ACC_STATIC)==0 ? 1 : 0, 4);
}
- public String getDescriptor() { return MethodRef.getDescriptor(ret,args); }
+ /** Returns the descriptor string for this method */
+ public String getDescriptor() { return MethodRef.getDescriptor(ret, args); }
private class ExnTableEnt {
public int start;
o.writeShort(pc[start]);
o.writeShort(end==pc.length ? endPC : pc[end]);
o.writeShort(pc[handler]);
- o.writeShort(typeEnt.getIndex());
+ o.writeShort(cp.getIndex(typeEnt));
}
}
- public final void addExceptionHandler(int startPC, int endPC, int handlerPC, Type.Object type) {
- exnTable.put(type, new ExnTableEnt(startPC,endPC,handlerPC,cp.add(type)));
+ /** Adds an exception handler for the range [<i>start</i>, <i>end</i>) pointing to <i>handler</i>
+ @param start The instruction to start at (inclusive)
+ @param end The instruction to end at (exclusive)
+ @param handler The instruction of the excepton handler
+ @param type The type of exception that is to be handled (MUST inherit from Throwable)
+ */
+ public final void addExceptionHandler(int start, int end, int handler, Type.Object type) {
+ exnTable.put(type, new ExnTableEnt(start, end, handler, cp.add(type)));
}
+ /** Adds a exception type that can be thrown from this method
+ NOTE: This isn't enforced by the JVM. This is for reference only. A method can throw exceptions not declared to be thrown
+ @param type The type of exception that can be thrown
+ */
public final void addThrow(Type.Object type) {
- thrownExceptions.put(type,cp.add(type));
+ thrownExceptions.put(type, cp.add(type));
}
private final void grow() { if(size == capacity) grow(size+1); }
if(capacity == NO_CODE) throw new IllegalStateException("method can't have code");
if(capacity == FINISHED) throw new IllegalStateException("method has been finished");
if(newCap <= capacity) return;
- newCap = Math.max(newCap,capacity == 0 ? 256 : capacity*2);
+ newCap = Math.max(newCap, capacity == 0 ? 256 : capacity*2);
byte[] op2 = new byte[newCap];
- if(capacity != 0) System.arraycopy(op,0,op2,0,size);
+ if(capacity != 0) System.arraycopy(op, 0, op2, 0, size);
op = op2;
Object[] arg2 = new Object[newCap];
- if(capacity != 0) System.arraycopy(arg,0,arg2,0,size);
+ if(capacity != 0) System.arraycopy(arg, 0, arg2, 0, size);
arg = arg2;
capacity = newCap;
}
+
+ /** Returns the size (in instructions) of this method
+ @return The size of the method (in instructions)
+ */
public final int size() { return size; }
// These two are optimized for speed, they don't call set() below
+ /** Add a bytecode (with no argument) to the method */
public final int add(byte op) {
int s = size;
if(s == capacity) grow();
size++;
return s;
}
+ /** Set the bytecode at position <i>pos</i> to <i>op</i> */
public final void set(int pos, byte op) { this.op[pos] = op; }
- public final int add(byte op, Object arg) { if(capacity == size) grow(); set(size,op,arg); return size++; }
- public final int add(byte op, boolean arg) { if(capacity == size) grow(); set(size,op,arg); return size++; }
- public final int add(byte op, int arg) { if(capacity == size) grow(); set(size,op,arg); return size++; }
+ /** Adds a bytecode, <i>op</i>, with argument <i>arg</i> to the method
+ @return The position of the new bytecode
+ */
+ public final int add(byte op, Object arg) { if(capacity == size) grow(); set(size, op, arg); return size++; }
+ /** Adds a bytecode with a boolean argument - equivalent to add(op, arg?1:0);
+ @return The position of the new bytecode
+ @see #add(byte, int)
+ */
+ public final int add(byte op, boolean arg) { if(capacity == size) grow(); set(size, op, arg); return size++; }
+ /** Adds a bytecode with an integer argument. This is equivalent to add(op, new Integer(arg)), but optimized to prevent the allocation when possible
+ @return The position of the new bytecode
+ @see #add(byte, Object)
+ */
+ public final int add(byte op, int arg) { if(capacity == size) grow(); set(size, op, arg); return size++; }
+ /** Gets the bytecode at position <i>pos</i>
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ */
public final byte get(int pos) { return op[pos]; }
- public final Object getArg(int pos) { return arg[pos]; }
- public final void setArg(int pos, int arg) { set(pos,op[pos],N(arg)); }
- public final void setArg(int pos, Object arg) { set(pos,op[pos],arg); }
+ /** Gets the bytecode at position <i>pos</i>. NOTE: This isn't necessarily the same object that was set with add or set.
+ Arguments for instructions which access the constant pool (LDC, INVOKEVIRTUAL, etc) are converted to a more efficient
+ interal form when they are added. The value returned from this method for these instruction can be reused, but there
+ is no way to retrieve the original object
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ */
+ public final Object getArg(int pos) { return arg[pos]; }
+ /** Sets the argument for <i>pos</i> to <i>arg</i>. This is equivalent to set(pos, op, new Integer(arg)), but optimized to prevent the allocation when possible.
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ @see #setArg(int, Object) */
+ public final void setArg(int pos, int arg) { set(pos, op[pos], N(arg)); }
+ /** Sets the argument for <i>pos</i> to <i>arg</i>.
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ */
+ public final void setArg(int pos, Object arg) { set(pos, op[pos], arg); }
- public final void set(int pos, byte op, boolean b) { set(pos,op,b?1:0); }
+ /** Sets the bytecode and argument at <i>pos</i> to <i>op</i> and <i>arg</i> respectivly.
+ This is equivalent to set(pos, op, arg?1:0)
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ */
+ public final void set(int pos, byte op, boolean arg) { set(pos, op, arg?1:0); }
- // This MUST handle x{LOAD,STORE} and LDC with an int arg WITHOUT falling back to set(int,byte,Object)
+ // This MUST handle x{LOAD, STORE} and LDC with an int arg WITHOUT falling back to set(int, byte, Object)
+ /** Sets the bytecode and argument at <i>pos</i> to <i>op</i> and <i>n</i> respectivly.
+ This is equivalent to set(pos, op, new Integer(n)), but optimized to prevent the allocation when possible.
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ */
public final void set(int pos, byte op, int n) {
Object arg = null;
OUTER: switch(op) {
break;
case ILOAD: case ISTORE: case LLOAD: case LSTORE: case FLOAD:
case FSTORE: case DLOAD: case DSTORE: case ALOAD: case ASTORE:
+ if(n >= maxLocals) maxLocals = n + 1;
if(n >= 0 && n <= 3) {
byte base = 0;
switch(op) {
}
op = (byte)((base&0xff) + n);
} else {
- if(n >= maxLocals) maxLocals = n + 1;
arg = N(n);
}
break;
default:
- set(pos,op,N(n));
+ set(pos, op, N(n));
return;
}
this.op[pos] = op;
this.arg[pos] = arg;
}
+ /** Sets the bytecode and argument at <i>pos</i> to <i>op</i> and <i>arg</i> respectivly.
+ @exception ArrayIndexOutOfBoundException if pos < 0 || pos >= size()
+ */
public final void set(int pos, byte op, Object arg) {
switch(op) {
case ILOAD: case ISTORE: case LLOAD: case LSTORE: case FLOAD:
case FSTORE: case DLOAD: case DSTORE: case ALOAD: case ASTORE:
- // set(int,byte,int) always handles these ops itself
- set(pos,op,((Integer)arg).intValue());
+ // set(int, byte, int) always handles these ops itself
+ set(pos, op, ((Integer)arg).intValue());
return;
case LDC:
- // set(int,byte,int) always handles these opts itself
- if(arg instanceof Integer) { set(pos,op,((Integer)arg).intValue()); return; }
- if(arg instanceof Boolean) { set(pos,op,((Boolean)arg).booleanValue()); return; }
+ // set(int, byte, int) always handles these opts itself
+ if(arg instanceof Integer) { set(pos, op, ((Integer)arg).intValue()); return; }
+ if(arg instanceof Boolean) { set(pos, op, ((Boolean)arg).booleanValue()); return; }
if(arg instanceof Long) {
long l = ((Long)arg).longValue();
this.arg[pos] = arg;
}
- public static class SI {
+ /** This class represents the arguments to the TABLESWITH and LOOKUPSWITCH bytecodes
+ @see MethodGen.TSI
+ @see MethodGen.LSI
+ */
+ public static abstract class SI {
public final Object[] targets;
public Object defaultTarget;
public int size() { return targets.length; }
public int getTarget(int pos) { return ((Integer)targets[pos]).intValue(); }
- public int getDefaultTarget() { return ((Integer)defaultTarget).intValue(); }
+ public int getDefaultTarget() { return ((Integer)defaultTarget).intValue(); }
+
+ abstract int length();
}
+ /** This class represents the arguments to the TABLESWITCH bytecode */
public static class TSI extends SI {
public final int lo;
public final int hi;
- public int defaultTarget = -1;
public TSI(int lo, int hi) {
super(hi-lo+1);
this.lo = lo;
this.hi = hi;
}
- public void setTargetForVal(int val, Object o) { setTarget(val-lo,o); }
- public void setTargetForVal(int val, int n) { setTarget(val-lo,n); }
+ public void setTargetForVal(int val, Object o) { setTarget(val-lo, o); }
+ public void setTargetForVal(int val, int n) { setTarget(val-lo, n); }
+
+ int length() { return 12 + targets.length * 4; } // 4bytes/target, hi, lo, default
}
+ /** This class represents the arguments to the LOOKUPSWITCH bytecode */
public static class LSI extends SI {
public final int[] vals;
public LSI(int size) {
this.vals = new int[size];
}
public final void setVal(int pos, int val) { vals[pos] = val; }
+
+ int length() { return 8 + targets.length * 8; } // key/val per target, default, count
}
+ /** This class represents the arguments to byecodes that take two integer arguments. */
public static class Pair {
public int i1;
public int i2;
public Pair(int i1, int i2) { this.i1 = i1; this.i2 = i2; }
}
+
+ public static class Wide {
+ public final byte op;
+ public final int varNum;
+ public final int n;
+ Wide(byte op, int varNum) { this(op, varNum, 0); }
+ Wide(byte op, int varNum, int n) { this.op = op; this.varNum = varNum; this.n = n; }
+ }
+ /** Sets the maximum number of locals in the function to <i>maxLocals</i>. NOTE: This defaults to 0 and is automatically increased as
+ necessary when *LOAD/*STORE bytecodes are added. You do not need to call this function in most cases */
public void setMaxLocals(int maxLocals) { this.maxLocals = maxLocals; }
+ /** Sets the maxinum size of th stack for this function to <i>maxStack</i>. This defaults to 16< */
public void setMaxStack(int maxStack) { this.maxStack = maxStack; }
+ /** Computes the final bytecode for this method.
+ @exception IllegalStateException if the data for a method is in an inconsistent state (required arguments missing, etc)
+ @exception Exn if the byteocode could not be generated for any other reason (constant pool full, etc)
+ */
public void finish() {
try {
_finish();
private void _finish() throws IOException {
if(size == FINISHED) return;
+ cp.stable();
+
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutput o = new DataOutputStream(baos);
int[] pc = new int[size];
int[] maxpc = pc;
- int p,i;
+ int p, i;
// Pass1 - Calculate maximum pc of each bytecode, widen some insns, resolve any unresolved jumps, etc
- for(i=0,p=0;i<size;i++) {
+ for(i=0, p=0;i<size;i++) {
byte op = this.op[i];
int opdata = OP_DATA[op&0xff];
int j;
}
switch(op) {
+ // Speical caculations
case GOTO:
- case JSR:
- p += 3;
- break;
+ case JSR: {
+ int arg = ((Integer)this.arg[i]).intValue();
+ if(arg < i && p - maxpc[arg] <= 32768) p += 3;
+ else p += 5;
+ continue;
+ }
case NOP:
if(EMIT_NOPS) p++;
- break;
+ continue;
case LOOKUPSWITCH:
case TABLESWITCH: {
SI si = (SI) arg[i];
Object[] targets = si.targets;
for(j=0;j<targets.length;j++) targets[j] = resolveTarget(targets[j]);
si.defaultTarget = resolveTarget(si.defaultTarget);
- p += 1 + 3 + 4; // opcode itself, padding, default
- if(op == TABLESWITCH) p += 4 + 4 + targets.length * 4; // lo, hi, targets
- else p += 4 + targets.length * 4 * 2; // count, key,val * targets
- if(op == LOOKUPSWITCH) {
+ p += 1 + 3 + si.length(); // opcode itself, padding, data
+ if(op == LOOKUPSWITCH) { // verify sanity of lookupswitch vals
int[] vals = ((LSI)si).vals;
for(j=1;j<vals.length;j++)
if(vals[j] <= vals[j-1])
throw new IllegalStateException("out of order/duplicate lookupswitch values");
}
+ continue;
+ }
+ // May need widening
+ case ILOAD: case ISTORE: case LLOAD: case LSTORE: case FLOAD:
+ case FSTORE: case DLOAD: case DSTORE: case ALOAD: case ASTORE:
+ case RET: {
+ int arg = ((Integer)this.arg[i]).intValue();
+ if(arg > 255) {
+ this.op[i] = WIDE;
+ this.arg[i] = new Wide(op, arg);
+ }
+ break;
+ }
+ case IINC: {
+ Pair pair = (Pair) this.arg[i];
+ if(pair.i1 > 255 || pair.i2 < -128 || pair.i2 > 127) {
+ this.op[i] = WIDE;
+ this.arg[i] = new Wide(IINC, pair.i1, pair.i2);
+ }
break;
}
case LDC:
- j = ((CPGen.Ent)arg[i]).getIndex();
+ j = cp.getIndex((CPGen.Ent)arg[i]);
if(j >= 256) this.op[i] = op = LDC_W;
- // fall through
- default:
- if((j = (opdata&OP_ARG_LENGTH_MASK)) == 7) throw new Error("shouldn't be here");
- p += 1 + j;
break;
+ default:
}
+ if((j = (opdata&OP_ARG_LENGTH_MASK)) == 7) throw new Error("shouldn't be here");
+ p += 1 + j;
}
// Pass2 - Widen instructions if they can possibly be too short
}
// Pass3 - Calculate actual pc
- for(i=0,p=0;i<size;i++) {
+ for(i=0, p=0;i<size;i++) {
byte op = this.op[i];
pc[i] = p;
switch(op) {
p = (p + 3) & ~3; // padding
p += 4; // default
if(op == TABLESWITCH) p += 4 + 4 + si.size() * 4; // lo, hi, targets
- else p += 4 + si.size() * 4 * 2; // count, key,val * targets
+ else p += 4 + si.size() * 4 * 2; // count, key, val * targets
break;
}
+ case WIDE:
+ p += 2 + (((Wide)arg[i]).op == IINC ? 4 : 2);
+ break;
default: {
int l = OP_DATA[op&0xff] & OP_ARG_LENGTH_MASK;
if(l == 7) throw new Error("shouldn't be here");
}
}
}
-
int codeSize = p;
+ if(codeSize >= 65536) throw new ClassGen.Exn("method too large in size");
+
o.writeShort(maxStack);
o.writeShort(maxLocals);
o.writeInt(codeSize);
byte op = this.op[i];
int opdata = OP_DATA[op&0xff];
if(op == NOP && !EMIT_NOPS) continue;
-
- o.writeByte(op&0xff);
+ o.writeByte(op);
int argLength = opdata & OP_ARG_LENGTH_MASK;
if(argLength == 0) continue; // skip if no args
if(pair.i1 > 255 || pair.i2 < -128 || pair.i2 > 127) throw new ClassGen.Exn("overflow of iinc arg");
o.writeByte(pair.i1);
o.writeByte(pair.i2);
+ break;
}
case TABLESWITCH:
case LOOKUPSWITCH: {
}
break;
}
- case WIDE:
- throw new Error("WIDE instruction not yet supported");
+ case WIDE: {
+ Wide wide = (Wide) arg;
+ o.writeByte(wide.op);
+ o.writeShort(wide.varNum);
+ if(wide.op == IINC) o.writeShort(wide.n);
+ break;
+ }
default:
if((opdata & OP_BRANCH_FLAG) != 0) {
int v = pc[((Integer)arg).intValue()] - pc[i];
- if(v < -32768 || v > 32767) throw new ClassGen.Exn("overflow of s2 offset");
- o.writeShort(v);
+ if(argLength == 2) {
+ if(v < -32768 || v > 32767) throw new ClassGen.Exn("overflow of s2 offset");
+ o.writeShort(v);
+ } else if(argLength == 4) {
+ o.writeInt(v);
+ } else {
+ throw new Error("should never happen");
+ }
} else if((opdata & OP_CPENT_FLAG) != 0) {
- int v = ((CPGen.Ent)arg).getIndex();
+ int v = cp.getIndex((CPGen.Ent)arg);
if(argLength == 1) o.writeByte(v);
else if(argLength == 2) o.writeShort(v);
else throw new Error("should never happen");
o.writeShort(exnTable.size());
for(Enumeration e = exnTable.keys();e.hasMoreElements();)
- ((ExnTableEnt)exnTable.get(e.nextElement())).dump(o,pc,codeSize);
+ ((ExnTableEnt)exnTable.get(e.nextElement())).dump(o, pc, codeSize);
o.writeShort(codeAttrs.size());
codeAttrs.dump(o);
baos.close();
byte[] codeAttribute = baos.toByteArray();
- attrs.add("Code",codeAttribute);
+ attrs.add("Code", codeAttribute);
baos.reset();
o.writeShort(thrownExceptions.size());
for(Enumeration e = thrownExceptions.keys();e.hasMoreElements();)
- o.writeShort(((CPGen.Ent)thrownExceptions.get(e.nextElement())).getIndex());
- attrs.add("Exceptions",baos.toByteArray());
+ o.writeShort(cp.getIndex((CPGen.Ent)thrownExceptions.get(e.nextElement())));
+ attrs.add("Exceptions", baos.toByteArray());
size = capacity = FINISHED;
}
- public void dump(DataOutput o) throws IOException {
+ void dump(DataOutput o) throws IOException {
o.writeShort(flags);
o.writeShort(cp.getUtf8Index(name));
o.writeShort(cp.getUtf8Index(getDescriptor()));
attrs.dump(o);
}
+ /** Negates the IF* instruction, <i>op</i> (IF_ICMPGT -> IF_ICMPLE, IFNE -> IFEQ, etc)
+ @exception IllegalArgumentException if <i>op</i> isn't an IF* instruction */
public static byte negate(byte op) {
switch(op) {
case IFEQ: return IFNE;
}
}
+ /** Class that represents a target that isn't currently know. The target MUST be set with setTarget() before the classfile is written.
+ This class is more or less a mutable integer */
public static class PhantomTarget {
private int target = -1;
public void setTarget(int target) { this.target = target; }