/
CodeGen.java
2044 lines (1771 loc) · 63.2 KB
/
CodeGen.java
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/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.compiler;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javassist.bytecode.Bytecode;
import javassist.bytecode.Opcode;
import javassist.compiler.ast.ASTList;
import javassist.compiler.ast.ASTree;
import javassist.compiler.ast.ArrayInit;
import javassist.compiler.ast.AssignExpr;
import javassist.compiler.ast.BinExpr;
import javassist.compiler.ast.CallExpr;
import javassist.compiler.ast.CastExpr;
import javassist.compiler.ast.CondExpr;
import javassist.compiler.ast.Declarator;
import javassist.compiler.ast.DoubleConst;
import javassist.compiler.ast.Expr;
import javassist.compiler.ast.FieldDecl;
import javassist.compiler.ast.InstanceOfExpr;
import javassist.compiler.ast.IntConst;
import javassist.compiler.ast.Keyword;
import javassist.compiler.ast.Member;
import javassist.compiler.ast.MethodDecl;
import javassist.compiler.ast.NewExpr;
import javassist.compiler.ast.Pair;
import javassist.compiler.ast.Stmnt;
import javassist.compiler.ast.StringL;
import javassist.compiler.ast.Symbol;
import javassist.compiler.ast.Variable;
import javassist.compiler.ast.Visitor;
/* The code generator is implemented by three files:
* CodeGen.java, MemberCodeGen.java, and JvstCodeGen.
* I just wanted to split a big file into three smaller ones.
*/
public abstract class CodeGen extends Visitor implements Opcode, TokenId {
static final String javaLangObject = "java.lang.Object";
static final String jvmJavaLangObject = "java/lang/Object";
static final String javaLangString = "java.lang.String";
static final String jvmJavaLangString = "java/lang/String";
protected Bytecode bytecode;
private int tempVar;
TypeChecker typeChecker;
/**
* true if the last visited node is a return statement.
*/
protected boolean hasReturned;
/**
* Must be true if compilation is for a static method.
*/
public boolean inStaticMethod;
protected List<Integer> breakList, continueList;
/**
* doit() in ReturnHook is called from atReturn().
*/
protected static abstract class ReturnHook {
ReturnHook next;
/**
* Returns true if the generated code ends with return,
* throw, or goto.
*/
protected abstract boolean doit(Bytecode b, int opcode);
protected ReturnHook(CodeGen gen) {
next = gen.returnHooks;
gen.returnHooks = this;
}
protected void remove(CodeGen gen) {
gen.returnHooks = next;
}
}
protected ReturnHook returnHooks;
/* The following fields are used by atXXX() methods
* for returning the type of the compiled expression.
*/
protected int exprType; // VOID, NULL, CLASS, BOOLEAN, INT, ...
protected int arrayDim;
protected String className; // JVM-internal representation
public CodeGen(Bytecode b) {
bytecode = b;
tempVar = -1;
typeChecker = null;
hasReturned = false;
inStaticMethod = false;
breakList = null;
continueList = null;
returnHooks = null;
}
public void setTypeChecker(TypeChecker checker) {
typeChecker = checker;
}
protected static void fatal() throws CompileError {
throw new CompileError("fatal");
}
public static boolean is2word(int type, int dim) {
return dim == 0 && (type == DOUBLE || type == LONG);
}
public int getMaxLocals() { return bytecode.getMaxLocals(); }
public void setMaxLocals(int n) {
bytecode.setMaxLocals(n);
}
protected void incMaxLocals(int size) {
bytecode.incMaxLocals(size);
}
/**
* Returns a local variable that single or double words can be
* stored in.
*/
protected int getTempVar() {
if (tempVar < 0) {
tempVar = getMaxLocals();
incMaxLocals(2);
}
return tempVar;
}
protected int getLocalVar(Declarator d) {
int v = d.getLocalVar();
if (v < 0) {
v = getMaxLocals(); // delayed variable allocation.
d.setLocalVar(v);
incMaxLocals(1);
}
return v;
}
/**
* Returns the JVM-internal representation of this class name.
*/
protected abstract String getThisName();
/**
* Returns the JVM-internal representation of this super class name.
*/
protected abstract String getSuperName() throws CompileError;
/* Converts a class name into a JVM-internal representation.
*
* It may also expand a simple class name to java.lang.*.
* For example, this converts Object into java/lang/Object.
*/
protected abstract String resolveClassName(ASTList name)
throws CompileError;
/* Expands a simple class name to java.lang.*.
* For example, this converts Object into java/lang/Object.
*/
protected abstract String resolveClassName(String jvmClassName)
throws CompileError;
/**
* @param name the JVM-internal representation.
* name is not exapnded to java.lang.*.
*/
protected static String toJvmArrayName(String name, int dim) {
if (name == null)
return null;
if (dim == 0)
return name;
StringBuffer sbuf = new StringBuffer();
int d = dim;
while (d-- > 0)
sbuf.append('[');
sbuf.append('L');
sbuf.append(name);
sbuf.append(';');
return sbuf.toString();
}
protected static String toJvmTypeName(int type, int dim) {
char c = 'I';
switch(type) {
case BOOLEAN :
c = 'Z';
break;
case BYTE :
c = 'B';
break;
case CHAR :
c = 'C';
break;
case SHORT :
c = 'S';
break;
case INT :
c = 'I';
break;
case LONG :
c = 'J';
break;
case FLOAT :
c = 'F';
break;
case DOUBLE :
c = 'D';
break;
case VOID :
c = 'V';
break;
}
StringBuffer sbuf = new StringBuffer();
while (dim-- > 0)
sbuf.append('[');
sbuf.append(c);
return sbuf.toString();
}
public void compileExpr(ASTree expr) throws CompileError {
doTypeCheck(expr);
expr.accept(this);
}
public boolean compileBooleanExpr(boolean branchIf, ASTree expr)
throws CompileError
{
doTypeCheck(expr);
return booleanExpr(branchIf, expr);
}
public void doTypeCheck(ASTree expr) throws CompileError {
if (typeChecker != null)
expr.accept(typeChecker);
}
@Override
public void atASTList(ASTList n) throws CompileError { fatal(); }
@Override
public void atPair(Pair n) throws CompileError { fatal(); }
@Override
public void atSymbol(Symbol n) throws CompileError { fatal(); }
@Override
public void atFieldDecl(FieldDecl field) throws CompileError {
field.getInit().accept(this);
}
@Override
public void atMethodDecl(MethodDecl method) throws CompileError {
ASTList mods = method.getModifiers();
setMaxLocals(1);
while (mods != null) {
Keyword k = (Keyword)mods.head();
mods = mods.tail();
if (k.get() == STATIC) {
setMaxLocals(0);
inStaticMethod = true;
}
}
ASTList params = method.getParams();
while (params != null) {
atDeclarator((Declarator)params.head());
params = params.tail();
}
Stmnt s = method.getBody();
atMethodBody(s, method.isConstructor(),
method.getReturn().getType() == VOID);
}
/**
* @param isCons true if super() must be called.
* false if the method is a class initializer.
*/
public void atMethodBody(Stmnt s, boolean isCons, boolean isVoid)
throws CompileError
{
if (s == null)
return;
if (isCons && needsSuperCall(s))
insertDefaultSuperCall();
hasReturned = false;
s.accept(this);
if (!hasReturned)
if (isVoid) {
bytecode.addOpcode(Opcode.RETURN);
hasReturned = true;
}
else
throw new CompileError("no return statement");
}
private boolean needsSuperCall(Stmnt body) throws CompileError {
if (body.getOperator() == BLOCK)
body = (Stmnt)body.head();
if (body != null && body.getOperator() == EXPR) {
ASTree expr = body.head();
if (expr != null && expr instanceof Expr
&& ((Expr)expr).getOperator() == CALL) {
ASTree target = ((Expr)expr).head();
if (target instanceof Keyword) {
int token = ((Keyword)target).get();
return token != THIS && token != SUPER;
}
}
}
return true;
}
protected abstract void insertDefaultSuperCall() throws CompileError;
@Override
public void atStmnt(Stmnt st) throws CompileError {
if (st == null)
return; // empty
int op = st.getOperator();
if (op == EXPR) {
ASTree expr = st.getLeft();
doTypeCheck(expr);
if (expr instanceof AssignExpr)
atAssignExpr((AssignExpr)expr, false);
else if (isPlusPlusExpr(expr)) {
Expr e = (Expr)expr;
atPlusPlus(e.getOperator(), e.oprand1(), e, false);
}
else {
expr.accept(this);
if (is2word(exprType, arrayDim))
bytecode.addOpcode(POP2);
else if (exprType != VOID)
bytecode.addOpcode(POP);
}
}
else if (op == DECL || op == BLOCK) {
ASTList list = st;
while (list != null) {
ASTree h = list.head();
list = list.tail();
if (h != null)
h.accept(this);
}
}
else if (op == IF)
atIfStmnt(st);
else if (op == WHILE || op == DO)
atWhileStmnt(st, op == WHILE);
else if (op == FOR)
atForStmnt(st);
else if (op == BREAK || op == CONTINUE)
atBreakStmnt(st, op == BREAK);
else if (op == TokenId.RETURN)
atReturnStmnt(st);
else if (op == THROW)
atThrowStmnt(st);
else if (op == TRY)
atTryStmnt(st);
else if (op == SWITCH)
atSwitchStmnt(st);
else if (op == SYNCHRONIZED)
atSyncStmnt(st);
else {
// LABEL, SWITCH label stament might be null?.
hasReturned = false;
throw new CompileError(
"sorry, not supported statement: TokenId " + op);
}
}
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;
}
}
private void atWhileStmnt(Stmnt st, boolean notDo) throws CompileError {
List<Integer> prevBreakList = breakList;
List<Integer> prevContList = continueList;
breakList = new ArrayList<Integer>();
continueList = new ArrayList<Integer>();
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;
}
protected void patchGoto(List<Integer> list, int targetPc) {
for (int pc:list)
bytecode.write16bit(pc, targetPc - pc + 1);
}
private void atForStmnt(Stmnt st) throws CompileError {
List<Integer> prevBreakList = breakList;
List<Integer> prevContList = continueList;
breakList = new ArrayList<Integer>();
continueList = new ArrayList<Integer>();
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;
}
private void atSwitchStmnt(Stmnt st) throws CompileError {
boolean isString = false;
if (typeChecker != null) {
doTypeCheck(st.head());
isString = typeChecker.exprType == TypeChecker.CLASS
&& typeChecker.arrayDim == 0
&& TypeChecker.jvmJavaLangString.equals(typeChecker.className);
}
compileExpr(st.head());
int tmpVar = -1;
if (isString) {
tmpVar = getMaxLocals();
incMaxLocals(1);
bytecode.addAstore(tmpVar);
bytecode.addAload(tmpVar);
bytecode.addInvokevirtual(TypeChecker.jvmJavaLangString, "hashCode", "()I");
}
List<Integer> prevBreakList = breakList;
breakList = new ArrayList<Integer>();
int opcodePc = bytecode.currentPc();
bytecode.addOpcode(LOOKUPSWITCH);
int npads = 3 - (opcodePc & 3);
while (npads-- > 0)
bytecode.add(0);
Stmnt body = (Stmnt)st.tail();
int npairs = 0;
for (ASTList list = body; list != null; list = list.tail())
if (((Stmnt)list.head()).getOperator() == CASE)
++npairs;
// opcodePc2 is the position at which the default jump offset is.
int opcodePc2 = bytecode.currentPc();
bytecode.addGap(4);
bytecode.add32bit(npairs);
bytecode.addGap(npairs * 8);
long[] pairs = new long[npairs];
ArrayList<Integer> gotoDefaults = new ArrayList<Integer>();
int ipairs = 0;
int defaultPc = -1;
for (ASTList list = body; list != null; list = list.tail()) {
Stmnt label = (Stmnt)list.head();
int op = label.getOperator();
if (op == DEFAULT)
defaultPc = bytecode.currentPc();
else if (op != CASE)
fatal();
else {
int curPos = bytecode.currentPc();
long caseLabel;
if (isString) {
// computeStringLabel() also adds bytecode as its side-effects.
caseLabel = (long)computeStringLabel(label.head(), tmpVar, gotoDefaults);
}
else
caseLabel = (long)computeLabel(label.head());
pairs[ipairs++]
= (caseLabel << 32) +
((long)(curPos - opcodePc) & 0xffffffff);
}
hasReturned = false;
((Stmnt)label.tail()).accept(this);
}
Arrays.sort(pairs);
int pc = opcodePc2 + 8;
for (int i = 0; i < npairs; ++i) {
bytecode.write32bit(pc, (int)(pairs[i] >>> 32));
bytecode.write32bit(pc + 4, (int)pairs[i]);
pc += 8;
}
if (defaultPc < 0 || breakList.size() > 0)
hasReturned = false;
int endPc = bytecode.currentPc();
if (defaultPc < 0)
defaultPc = endPc;
bytecode.write32bit(opcodePc2, defaultPc - opcodePc);
for (int addr: gotoDefaults)
bytecode.write16bit(addr, defaultPc - addr + 1);
patchGoto(breakList, endPc);
breakList = prevBreakList;
}
private int computeLabel(ASTree expr) throws CompileError {
doTypeCheck(expr);
expr = TypeChecker.stripPlusExpr(expr);
if (expr instanceof IntConst)
return (int)((IntConst)expr).get();
throw new CompileError("bad case label");
}
private int computeStringLabel(ASTree expr, int tmpVar, List<Integer> gotoDefaults)
throws CompileError
{
doTypeCheck(expr);
expr = TypeChecker.stripPlusExpr(expr);
if (expr instanceof StringL) {
String label = ((StringL)expr).get();
bytecode.addAload(tmpVar);
bytecode.addLdc(label);
bytecode.addInvokevirtual(TypeChecker.jvmJavaLangString, "equals",
"(Ljava/lang/Object;)Z");
bytecode.addOpcode(IFEQ);
Integer pc = Integer.valueOf(bytecode.currentPc());
bytecode.addIndex(0);
gotoDefaults.add(pc);
return (int)label.hashCode();
}
throw new CompileError("bad case label");
}
private void atBreakStmnt(Stmnt st, boolean notCont)
throws CompileError
{
if (st.head() != null)
throw new CompileError(
"sorry, not support labeled break or continue");
bytecode.addOpcode(Opcode.GOTO);
Integer pc = Integer.valueOf(bytecode.currentPc());
bytecode.addIndex(0);
if (notCont)
breakList.add(pc);
else
continueList.add(pc);
}
protected void atReturnStmnt(Stmnt st) throws CompileError {
atReturnStmnt2(st.getLeft());
}
protected final void atReturnStmnt2(ASTree result) throws CompileError {
int op;
if (result == null)
op = Opcode.RETURN;
else {
compileExpr(result);
if (arrayDim > 0)
op = ARETURN;
else {
int type = exprType;
if (type == DOUBLE)
op = DRETURN;
else if (type == FLOAT)
op = FRETURN;
else if (type == LONG)
op = LRETURN;
else if (isRefType(type))
op = ARETURN;
else
op = IRETURN;
}
}
for (ReturnHook har = returnHooks; har != null; har = har.next)
if (har.doit(bytecode, op)) {
hasReturned = true;
return;
}
bytecode.addOpcode(op);
hasReturned = true;
}
private void atThrowStmnt(Stmnt st) throws CompileError {
ASTree e = st.getLeft();
compileExpr(e);
if (exprType != CLASS || arrayDim > 0)
throw new CompileError("bad throw statement");
bytecode.addOpcode(ATHROW);
hasReturned = true;
}
/* overridden in MemberCodeGen
*/
protected void atTryStmnt(Stmnt st) throws CompileError {
hasReturned = false;
}
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) {
@Override
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 static int getListSize(List<Integer> list) {
return list == null ? 0 : list.size();
}
private static boolean isPlusPlusExpr(ASTree expr) {
if (expr instanceof Expr) {
int op = ((Expr)expr).getOperator();
return op == PLUSPLUS || op == MINUSMINUS;
}
return false;
}
@Override
public void atDeclarator(Declarator d) throws CompileError {
d.setLocalVar(getMaxLocals());
d.setClassName(resolveClassName(d.getClassName()));
int size;
if (is2word(d.getType(), d.getArrayDim()))
size = 2;
else
size = 1;
incMaxLocals(size);
/* NOTE: Array initializers has not been supported.
*/
ASTree init = d.getInitializer();
if (init != null) {
doTypeCheck(init);
atVariableAssign(null, '=', null, d, init, false);
}
}
@Override
public abstract void atNewExpr(NewExpr n) throws CompileError;
@Override
public abstract void atArrayInit(ArrayInit init) throws CompileError;
@Override
public void atAssignExpr(AssignExpr expr) throws CompileError {
atAssignExpr(expr, true);
}
protected void atAssignExpr(AssignExpr expr, boolean doDup)
throws CompileError
{
// =, %=, &=, *=, /=, +=, -=, ^=, |=, <<=, >>=, >>>=
int op = expr.getOperator();
ASTree left = expr.oprand1();
ASTree right = expr.oprand2();
if (left instanceof Variable)
atVariableAssign(expr, op, (Variable)left,
((Variable)left).getDeclarator(),
right, doDup);
else {
if (left instanceof Expr) {
Expr e = (Expr)left;
if (e.getOperator() == ARRAY) {
atArrayAssign(expr, op, (Expr)left, right, doDup);
return;
}
}
atFieldAssign(expr, op, left, right, doDup);
}
}
protected static void badAssign(Expr expr) throws CompileError {
String msg;
if (expr == null)
msg = "incompatible type for assignment";
else
msg = "incompatible type for " + expr.getName();
throw new CompileError(msg);
}
/* op is either =, %=, &=, *=, /=, +=, -=, ^=, |=, <<=, >>=, or >>>=.
*
* expr and var can be null.
*/
private void atVariableAssign(Expr expr, int op, Variable var,
Declarator d, ASTree right,
boolean doDup) throws CompileError
{
int varType = d.getType();
int varArray = d.getArrayDim();
String varClass = d.getClassName();
int varNo = getLocalVar(d);
if (op != '=')
atVariable(var);
// expr is null if the caller is atDeclarator().
if (expr == null && right instanceof ArrayInit)
atArrayVariableAssign((ArrayInit)right, varType, varArray, varClass);
else
atAssignCore(expr, op, right, varType, varArray, varClass);
if (doDup)
if (is2word(varType, varArray))
bytecode.addOpcode(DUP2);
else
bytecode.addOpcode(DUP);
if (varArray > 0)
bytecode.addAstore(varNo);
else if (varType == DOUBLE)
bytecode.addDstore(varNo);
else if (varType == FLOAT)
bytecode.addFstore(varNo);
else if (varType == LONG)
bytecode.addLstore(varNo);
else if (isRefType(varType))
bytecode.addAstore(varNo);
else
bytecode.addIstore(varNo);
exprType = varType;
arrayDim = varArray;
className = varClass;
}
protected abstract void atArrayVariableAssign(ArrayInit init,
int varType, int varArray, String varClass) throws CompileError;
private void atArrayAssign(Expr expr, int op, Expr array,
ASTree right, boolean doDup) throws CompileError
{
arrayAccess(array.oprand1(), array.oprand2());
if (op != '=') {
bytecode.addOpcode(DUP2);
bytecode.addOpcode(getArrayReadOp(exprType, arrayDim));
}
int aType = exprType;
int aDim = arrayDim;
String cname = className;
atAssignCore(expr, op, right, aType, aDim, cname);
if (doDup)
if (is2word(aType, aDim))
bytecode.addOpcode(DUP2_X2);
else
bytecode.addOpcode(DUP_X2);
bytecode.addOpcode(getArrayWriteOp(aType, aDim));
exprType = aType;
arrayDim = aDim;
className = cname;
}
protected abstract void atFieldAssign(Expr expr, int op, ASTree left,
ASTree right, boolean doDup) throws CompileError;
protected void atAssignCore(Expr expr, int op, ASTree right,
int type, int dim, String cname)
throws CompileError
{
if (op == PLUS_E && dim == 0 && type == CLASS)
atStringPlusEq(expr, type, dim, cname, right);
else {
right.accept(this);
if (invalidDim(exprType, arrayDim, className, type, dim, cname,
false) || (op != '=' && dim > 0))
badAssign(expr);
if (op != '=') {
int token = assignOps[op - MOD_E];
int k = lookupBinOp(token);
if (k < 0)
fatal();
atArithBinExpr(expr, token, k, type);
}
}
if (op != '=' || (dim == 0 && !isRefType(type)))
atNumCastExpr(exprType, type);
// type check should be done here.
}
private void atStringPlusEq(Expr expr, int type, int dim, String cname,
ASTree right)
throws CompileError
{
if (!jvmJavaLangString.equals(cname))
badAssign(expr);
convToString(type, dim); // the value might be null.
right.accept(this);
convToString(exprType, arrayDim);
bytecode.addInvokevirtual(javaLangString, "concat",
"(Ljava/lang/String;)Ljava/lang/String;");
exprType = CLASS;
arrayDim = 0;
className = jvmJavaLangString;
}
private boolean invalidDim(int srcType, int srcDim, String srcClass,
int destType, int destDim, String destClass,
boolean isCast)
{
if (srcDim != destDim)
if (srcType == NULL)
return false;