6966737: (pack200) the pack200 regression tests need to be more robust.
Reviewed-by: jrose, ohair
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 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 xmlkit; // -*- mode: java; indent-tabs-mode: nil -*-
import xmlkit.XMLKit.Element;
import java.util.HashMap;
/*
* @author jrose
*/
abstract class InstructionAssembler extends InstructionSyntax {
InstructionAssembler() {
}
public static String assemble(Element instructions, String pcAttrName,
ClassSyntax.GetCPIndex getCPI) {
int insCount = instructions.size();
Element[] insElems = new Element[insCount];
int[] elemToIndexMap;
int[] insLocs;
byte[] ops = new byte[insCount];
int[] operands = new int[insCount];
boolean[] isWide = new boolean[insCount];
int[] branches;
int[] branchInsLocs;
HashMap<String, String> labels = new HashMap<String, String>();
final int WIDE = 0xc4;
final int GOTO = 0xa7;
final int GOTO_W = 0xc8;
final int GOTO_LEN = 3;
final int GOTO_W_LEN = 5;
assert ("wide".equals(bcNames[WIDE]));
assert ("goto".equals(bcNames[GOTO]));
assert ("goto_w".equals(bcNames[GOTO_W]));
assert (bcFormats[GOTO].length() == GOTO_LEN);
assert (bcFormats[GOTO_W].length() == GOTO_W_LEN);
// Unpack instructions into temp. arrays, and find branches and labels.
{
elemToIndexMap = (pcAttrName != null) ? new int[insCount] : null;
int[] buffer = operands;
int id = 0;
int branchCount = 0;
for (int i = 0; i < insCount; i++) {
Element ins = (Element) instructions.get(i);
if (elemToIndexMap != null) {
elemToIndexMap[i] = (ins.getAttr(pcAttrName) != null ? id : -1);
}
String lab = ins.getAttr("pc");
if (lab != null) {
labels.put(lab, String.valueOf(id));
}
int op = opCode(ins.getName());
if (op < 0) {
assert (ins.getAttr(pcAttrName) != null
|| ins.getName().equals("label"));
continue; // delete PC holder element
}
if (op == WIDE) { //0xc4
isWide[id] = true; // force wide format
continue;
}
if (bcFormats[op].indexOf('o') >= 0) {
buffer[branchCount++] = id;
}
if (bcFormats[op] == bcWideFormats[op]) {
isWide[id] = false;
}
insElems[id] = ins;
ops[id] = (byte) op;
id++;
}
insCount = id; // maybe we deleted some wide prefixes, etc.
branches = new int[branchCount + 1];
System.arraycopy(buffer, 0, branches, 0, branchCount);
branches[branchCount] = -1; // sentinel
}
// Compute instruction sizes. These sizes are final,
// except for branch instructions, which may need lengthening.
// Some instructions (ldc, bipush, iload, iinc) are automagically widened.
insLocs = new int[insCount + 1];
int loc = 0;
for (int bn = 0, id = 0; id < insCount; id++) {
insLocs[id] = loc;
Element ins = insElems[id];
int op = ops[id] & 0xFF;
String format = opFormat(op, isWide[id]);
// Make sure operands fit within the given format.
for (int j = 1, jlimit = format.length(); j < jlimit; j++) {
char fc = format.charAt(j);
int x = 0;
switch (fc) {
case 'l':
x = (int) ins.getAttrLong("loc");
assert (x >= 0);
if (x > 0xFF && !isWide[id]) {
isWide[id] = true;
format = opFormat(op, isWide[id]);
}
assert (x <= 0xFFFF);
break;
case 'k':
char fc2 = format.charAt(Math.min(j + 1, format.length() - 1));
x = getCPIndex(ins, fc2, getCPI);
if (x > 0xFF && j == jlimit - 1) {
assert (op == 0x12); //ldc
ops[id] = (byte) (op = 0x13); //ldc_w
format = opFormat(op);
}
assert (x <= 0xFFFF);
j++; // skip type-of-constant marker
break;
case 'x':
x = (int) ins.getAttrLong("num");
assert (x >= 0 && x <= ((j == jlimit - 1) ? 0xFF : 0xFFFF));
break;
case 's':
x = (int) ins.getAttrLong("num");
if (x != (byte) x && j == jlimit - 1) {
switch (op) {
case 0x10: //bipush
ops[id] = (byte) (op = 0x11); //sipush
break;
case 0x84: //iinc
isWide[id] = true;
format = opFormat(op, isWide[id]);
break;
default:
assert (false); // cannot lengthen
}
}
// unsign the value now, to make later steps clearer
if (j == jlimit - 1) {
assert (x == (byte) x);
x = x & 0xFF;
} else {
assert (x == (short) x);
x = x & 0xFFFF;
}
break;
case 'o':
assert (branches[bn] == id);
bn++;
// make local copies of the branches, and fix up labels
insElems[id] = ins = new Element(ins);
String newLab = labels.get(ins.getAttr("lab"));
assert (newLab != null);
ins.setAttr("lab", newLab);
int prevCas = 0;
int k = 0;
for (Element cas : ins.elements()) {
assert (cas.getName().equals("Case"));
ins.set(k++, cas = new Element(cas));
newLab = labels.get(cas.getAttr("lab"));
assert (newLab != null);
cas.setAttr("lab", newLab);
int thisCas = (int) cas.getAttrLong("num");
assert (op == 0xab
|| op == 0xaa && (k == 0 || thisCas == prevCas + 1));
prevCas = thisCas;
}
break;
case 't':
// switch table is represented as Switch.Case sub-elements
break;
default:
assert (false);
}
operands[id] = x; // record operand (last if there are 2)
// skip redundant chars
while (j + 1 < jlimit && format.charAt(j + 1) == fc) {
++j;
}
}
switch (op) {
case 0xaa: //tableswitch
loc = switchBase(loc);
loc += 4 * (3 + ins.size());
break;
case 0xab: //lookupswitch
loc = switchBase(loc);
loc += 4 * (2 + 2 * ins.size());
break;
default:
if (isWide[id]) {
loc++; // 'wide' opcode prefix
}
loc += format.length();
break;
}
}
insLocs[insCount] = loc;
// compute branch offsets, and see if any branches need expansion
for (int maxTries = 9, tries = 0;; ++tries) {
boolean overflowing = false;
boolean[] branchExpansions = null;
for (int bn = 0; bn < branches.length - 1; bn++) {
int id = branches[bn];
Element ins = insElems[id];
int insSize = insLocs[id + 1] - insLocs[id];
int origin = insLocs[id];
int target = insLocs[(int) ins.getAttrLong("lab")];
int offset = target - origin;
operands[id] = offset;
//System.out.println("branch id="+id+" len="+insSize+" to="+target+" offset="+offset);
assert (insSize == GOTO_LEN || insSize == GOTO_W_LEN || ins.getName().indexOf("switch") > 0);
boolean thisOverflow = (insSize == GOTO_LEN && (offset != (short) offset));
if (thisOverflow && !overflowing) {
overflowing = true;
branchExpansions = new boolean[branches.length];
}
if (thisOverflow || tries == maxTries - 1) {
// lengthen the branch
assert (!(thisOverflow && isWide[id]));
isWide[id] = true;
branchExpansions[bn] = true;
}
}
if (!overflowing) {
break; // done, usually on first try
}
assert (tries <= maxTries);
// Walk over all instructions, expanding branches and updating locations.
int fixup = 0;
for (int bn = 0, id = 0; id < insCount; id++) {
insLocs[id] += fixup;
if (branches[bn] == id) {
int op = ops[id] & 0xFF;
int wop;
boolean invert;
if (branchExpansions[bn]) {
switch (op) {
case GOTO: //0xa7
wop = GOTO_W; //0xc8
invert = false;
break;
case 0xa8: //jsr
wop = 0xc9; //jsr_w
invert = false;
break;
default:
wop = invertBranchOp(op);
invert = true;
break;
}
assert (op != wop);
ops[id] = (byte) wop;
isWide[id] = invert;
if (invert) {
fixup += GOTO_W_LEN; //branch around a wide goto
} else {
fixup += (GOTO_W_LEN - GOTO_LEN);
}
// done expanding: ops and isWide reflect the decision
}
bn++;
}
}
insLocs[insCount] += fixup;
}
// we know the layout now
// notify the caller of offsets, if requested
if (elemToIndexMap != null) {
for (int i = 0; i < elemToIndexMap.length; i++) {
int id = elemToIndexMap[i];
if (id >= 0) {
Element ins = (Element) instructions.get(i);
ins.setAttr(pcAttrName, "" + insLocs[id]);
}
}
elemToIndexMap = null; // release the pointer
}
// output the bytes
StringBuffer sbuf = new StringBuffer(insLocs[insCount]);
for (int bn = 0, id = 0; id < insCount; id++) {
//System.out.println("output id="+id+" loc="+insLocs[id]+" len="+(insLocs[id+1]-insLocs[id])+" #sbuf="+sbuf.length());
assert (sbuf.length() == insLocs[id]);
Element ins;
int pc = insLocs[id];
int nextpc = insLocs[id + 1];
int op = ops[id] & 0xFF;
int opnd = operands[id];
String format;
if (branches[bn] == id) {
bn++;
sbuf.append((char) op);
if (isWide[id]) {
// emit <ifop lab=1f> <goto_w target> <label pc=1f>
int target = pc + opnd;
putInt(sbuf, nextpc - pc, -2);
assert (sbuf.length() == pc + GOTO_LEN);
sbuf.append((char) GOTO_W);
putInt(sbuf, target - (pc + GOTO_LEN), 4);
} else if (op == 0xaa || //tableswitch
op == 0xab) { //lookupswitch
ins = insElems[id];
for (int pad = switchBase(pc) - (pc + 1); pad > 0; pad--) {
sbuf.append((char) 0);
}
assert (pc + opnd == insLocs[(int) ins.getAttrLong("lab")]);
putInt(sbuf, opnd, 4); // default label
if (op == 0xaa) { //tableswitch
Element cas0 = (Element) ins.get(0);
int lowCase = (int) cas0.getAttrLong("num");
Element casN = (Element) ins.get(ins.size() - 1);
int highCase = (int) casN.getAttrLong("num");
assert (highCase - lowCase + 1 == ins.size());
putInt(sbuf, lowCase, 4);
putInt(sbuf, highCase, 4);
int caseForAssert = lowCase;
for (Element cas : ins.elements()) {
int target = insLocs[(int) cas.getAttrLong("lab")];
assert (cas.getAttrLong("num") == caseForAssert++);
putInt(sbuf, target - pc, 4);
}
} else { //lookupswitch
int caseCount = ins.size();
putInt(sbuf, caseCount, 4);
for (Element cas : ins.elements()) {
int target = insLocs[(int) cas.getAttrLong("lab")];
putInt(sbuf, (int) cas.getAttrLong("num"), 4);
putInt(sbuf, target - pc, 4);
}
}
assert (nextpc == sbuf.length());
} else {
putInt(sbuf, opnd, -(nextpc - (pc + 1)));
}
} else if (nextpc == pc + 1) {
// a single-byte instruction
sbuf.append((char) op);
} else {
// picky stuff
boolean wide = isWide[id];
if (wide) {
sbuf.append((char) WIDE);
pc++;
}
sbuf.append((char) op);
int opnd1;
int opnd2 = opnd;
switch (op) {
case 0x84: //iinc
ins = insElems[id];
opnd1 = (int) ins.getAttrLong("loc");
if (isWide[id]) {
putInt(sbuf, opnd1, 2);
putInt(sbuf, opnd2, 2);
} else {
putInt(sbuf, opnd1, 1);
putInt(sbuf, opnd2, 1);
}
break;
case 0xc5: //multianewarray
ins = insElems[id];
opnd1 = getCPIndex(ins, 'c', getCPI);
putInt(sbuf, opnd1, 2);
putInt(sbuf, opnd2, 1);
break;
case 0xb9: //invokeinterface
ins = insElems[id];
opnd1 = getCPIndex(ins, 'n', getCPI);
putInt(sbuf, opnd1, 2);
opnd2 = (int) ins.getAttrLong("num");
if (opnd2 == 0) {
opnd2 = ClassSyntax.computeInterfaceNum(ins.getAttr("val"));
}
putInt(sbuf, opnd2, 2);
break;
default:
// put the single operand and be done
putInt(sbuf, opnd, nextpc - (pc + 1));
break;
}
}
}
assert (sbuf.length() == insLocs[insCount]);
return sbuf.toString();
}
static int getCPIndex(Element ins, char ctype,
ClassSyntax.GetCPIndex getCPI) {
int x = (int) ins.getAttrLong("ref");
if (x == 0 && getCPI != null) {
String val = ins.getAttr("val");
if (val == null || val.equals("")) {
val = ins.getText().toString();
}
byte tag;
switch (ctype) {
case 'k':
tag = (byte) ins.getAttrLong("tag");
break;
case 'c':
tag = ClassSyntax.CONSTANT_Class;
break;
case 'f':
tag = ClassSyntax.CONSTANT_Fieldref;
break;
case 'm':
tag = ClassSyntax.CONSTANT_Methodref;
break;
case 'n':
tag = ClassSyntax.CONSTANT_InterfaceMethodref;
break;
default:
throw new Error("bad ctype " + ctype + " in " + ins);
}
x = getCPI.getCPIndex(tag, val);
//System.out.println("getCPIndex "+ins+" => "+tag+"/"+val+" => "+x);
} else {
assert (x > 0);
}
return x;
}
static void putInt(StringBuffer sbuf, int x, int len) {
//System.out.println("putInt x="+x+" len="+len);
boolean isSigned = false;
if (len < 0) {
len = -len;
isSigned = true;
}
assert (len == 1 || len == 2 || len == 4);
int insig = ((4 - len) * 8); // how many insignificant bits?
int sx = x << insig;
;
assert (x == (isSigned ? (sx >> insig) : (sx >>> insig)));
for (int i = 0; i < len; i++) {
sbuf.append((char) (sx >>> 24));
sx <<= 8;
}
}
}