private void atIfStmnt(Stmnt st) throws CompileError {
ASTree expr = st.head();
Stmnt thenp = (Stmnt) st.tail().head();
Stmnt elsep = (Stmnt) st.tail().tail().head();
if (compileBooleanExpr(false, expr)) {
hasReturned = false;
if (elsep != null) elsep.accept(this);
return;
}
int pc = bytecode.currentPc();
int pc2 = 0;
bytecode.addIndex(0); // correct later
hasReturned = false;
if (thenp != null) thenp.accept(this);
boolean thenHasReturned = hasReturned;
hasReturned = false;
if (elsep != null && !thenHasReturned) {
bytecode.addOpcode(Opcode.GOTO);
pc2 = bytecode.currentPc();
bytecode.addIndex(0);
}
bytecode.write16bit(pc, bytecode.currentPc() - pc + 1);
if (elsep != null) {
elsep.accept(this);
if (!thenHasReturned) bytecode.write16bit(pc2, bytecode.currentPc() - pc2 + 1);
hasReturned = thenHasReturned && hasReturned;
}
}
public void atCondExpr(CondExpr expr) throws CompileError {
booleanExpr(false, expr.condExpr());
int pc = bytecode.currentPc();
bytecode.addIndex(0); // correct later
expr.thenExpr().accept(this);
int dim1 = arrayDim;
bytecode.addOpcode(Opcode.GOTO);
int pc2 = bytecode.currentPc();
bytecode.addIndex(0);
bytecode.write16bit(pc, bytecode.currentPc() - pc + 1);
expr.elseExpr().accept(this);
if (dim1 != arrayDim) throw new CompileError("type mismatch in ?:");
bytecode.write16bit(pc2, bytecode.currentPc() - pc2 + 1);
}
protected void patchGoto(ArrayList list, int targetPc) {
int n = list.size();
for (int i = 0; i < n; ++i) {
int pc = ((Integer) list.get(i)).intValue();
bytecode.write16bit(pc, targetPc - pc + 1);
}
}
private void atWhileStmnt(Stmnt st, boolean notDo) throws CompileError {
ArrayList prevBreakList = breakList;
ArrayList prevContList = continueList;
breakList = new ArrayList();
continueList = new ArrayList();
ASTree expr = st.head();
Stmnt body = (Stmnt) st.tail();
int pc = 0;
if (notDo) {
bytecode.addOpcode(Opcode.GOTO);
pc = bytecode.currentPc();
bytecode.addIndex(0);
}
int pc2 = bytecode.currentPc();
if (body != null) body.accept(this);
int pc3 = bytecode.currentPc();
if (notDo) bytecode.write16bit(pc, pc3 - pc + 1);
boolean alwaysBranch = compileBooleanExpr(true, expr);
if (alwaysBranch) {
bytecode.addOpcode(Opcode.GOTO);
alwaysBranch = breakList.size() == 0;
}
bytecode.addIndex(pc2 - bytecode.currentPc() + 1);
patchGoto(breakList, bytecode.currentPc());
patchGoto(continueList, pc3);
continueList = prevContList;
breakList = prevBreakList;
hasReturned = alwaysBranch;
}
private void atSyncStmnt(Stmnt st) throws CompileError {
int nbreaks = getListSize(breakList);
int ncontinues = getListSize(continueList);
compileExpr(st.head());
if (exprType != CLASS && arrayDim == 0)
throw new CompileError("bad type expr for synchronized block");
Bytecode bc = bytecode;
final int var = bc.getMaxLocals();
bc.incMaxLocals(1);
bc.addOpcode(DUP);
bc.addAstore(var);
bc.addOpcode(MONITORENTER);
ReturnHook rh =
new ReturnHook(this) {
protected boolean doit(Bytecode b, int opcode) {
b.addAload(var);
b.addOpcode(MONITOREXIT);
return false;
}
};
int pc = bc.currentPc();
Stmnt body = (Stmnt) st.tail();
if (body != null) body.accept(this);
int pc2 = bc.currentPc();
int pc3 = 0;
if (!hasReturned) {
rh.doit(bc, 0); // the 2nd arg is ignored.
bc.addOpcode(Opcode.GOTO);
pc3 = bc.currentPc();
bc.addIndex(0);
}
if (pc < pc2) { // if the body is not empty
int pc4 = bc.currentPc();
rh.doit(bc, 0); // the 2nd arg is ignored.
bc.addOpcode(ATHROW);
bc.addExceptionHandler(pc, pc2, pc4, 0);
}
if (!hasReturned) bc.write16bit(pc3, bc.currentPc() - pc3 + 1);
rh.remove(this);
if (getListSize(breakList) != nbreaks || getListSize(continueList) != ncontinues)
throw new CompileError("sorry, cannot break/continue in synchronized block");
}
private void atForStmnt(Stmnt st) throws CompileError {
ArrayList prevBreakList = breakList;
ArrayList prevContList = continueList;
breakList = new ArrayList();
continueList = new ArrayList();
Stmnt init = (Stmnt) st.head();
ASTList p = st.tail();
ASTree expr = p.head();
p = p.tail();
Stmnt update = (Stmnt) p.head();
Stmnt body = (Stmnt) p.tail();
if (init != null) init.accept(this);
int pc = bytecode.currentPc();
int pc2 = 0;
if (expr != null) {
if (compileBooleanExpr(false, expr)) {
// in case of "for (...; false; ...)"
continueList = prevContList;
breakList = prevBreakList;
hasReturned = false;
return;
}
pc2 = bytecode.currentPc();
bytecode.addIndex(0);
}
if (body != null) body.accept(this);
int pc3 = bytecode.currentPc();
if (update != null) update.accept(this);
bytecode.addOpcode(Opcode.GOTO);
bytecode.addIndex(pc - bytecode.currentPc() + 1);
int pc4 = bytecode.currentPc();
if (expr != null) bytecode.write16bit(pc2, pc4 - pc2 + 1);
patchGoto(breakList, pc4);
patchGoto(continueList, pc3);
continueList = prevContList;
breakList = prevBreakList;
hasReturned = false;
}
/* Produces the opcode to branch if the condition is true.
* The oprand (branch offset) is not produced.
*
* @return true if the compiled code is GOTO (always branch).
* GOTO is not produced.
*/
private boolean booleanExpr(boolean branchIf, ASTree expr) throws CompileError {
boolean isAndAnd;
int op = getCompOperator(expr);
if (op == EQ) { // ==, !=, ...
BinExpr bexpr = (BinExpr) expr;
int type1 = compileOprands(bexpr);
// here, arrayDim might represent the array dim. of the left oprand
// if the right oprand is NULL.
compareExpr(branchIf, bexpr.getOperator(), type1, bexpr);
} else if (op == '!') return booleanExpr(!branchIf, ((Expr) expr).oprand1());
else if ((isAndAnd = (op == ANDAND)) || op == OROR) {
BinExpr bexpr = (BinExpr) expr;
if (booleanExpr(!isAndAnd, bexpr.oprand1())) {
exprType = BOOLEAN;
arrayDim = 0;
return true;
} else {
int pc = bytecode.currentPc();
bytecode.addIndex(0); // correct later
if (booleanExpr(isAndAnd, bexpr.oprand2())) bytecode.addOpcode(Opcode.GOTO);
bytecode.write16bit(pc, bytecode.currentPc() - pc + 3);
if (branchIf != isAndAnd) {
bytecode.addIndex(6); // skip GOTO instruction
bytecode.addOpcode(Opcode.GOTO);
}
}
} else if (isAlwaysBranch(expr, branchIf)) {
// Opcode.GOTO is not added here. The caller must add it.
exprType = BOOLEAN;
arrayDim = 0;
return true; // always branch
} else { // others
expr.accept(this);
if (exprType != BOOLEAN || arrayDim != 0) throw new CompileError("boolean expr is required");
bytecode.addOpcode(branchIf ? IFNE : IFEQ);
}
exprType = BOOLEAN;
arrayDim = 0;
return false;
}
/* MemberCodeGen overrides this method.
*/
protected void atClassObject2(String cname) throws CompileError {
int start = bytecode.currentPc();
bytecode.addLdc(cname);
bytecode.addInvokestatic("java.lang.Class", "forName", "(Ljava/lang/String;)Ljava/lang/Class;");
int end = bytecode.currentPc();
bytecode.addOpcode(Opcode.GOTO);
int pc = bytecode.currentPc();
bytecode.addIndex(0); // correct later
bytecode.addExceptionHandler(
start, end, bytecode.currentPc(), "java.lang.ClassNotFoundException");
/* -- the following code is for inlining a call to DotClass.fail().
int var = getMaxLocals();
incMaxLocals(1);
bytecode.growStack(1);
bytecode.addAstore(var);
bytecode.addNew("java.lang.NoClassDefFoundError");
bytecode.addOpcode(DUP);
bytecode.addAload(var);
bytecode.addInvokevirtual("java.lang.ClassNotFoundException",
"getMessage", "()Ljava/lang/String;");
bytecode.addInvokespecial("java.lang.NoClassDefFoundError", "<init>",
"(Ljava/lang/String;)V");
*/
bytecode.growStack(1);
bytecode.addInvokestatic(
"javassist.runtime.DotClass",
"fail",
"(Ljava/lang/ClassNotFoundException;)" + "Ljava/lang/NoClassDefFoundError;");
bytecode.addOpcode(ATHROW);
bytecode.write16bit(pc, bytecode.currentPc() - pc + 1);
}