6 public class DotExpr extends Expr {
12 static boolean DOMEMCHECKS=false;
13 static boolean DOTYPECHECKS=false;
14 static boolean DONULL=false;
17 public DotExpr(Expr left, String field, Expr index) {
23 public boolean isInvariant(Set vars) {
24 if (!left.isInvariant(vars))
27 return intindex.isInvariant(vars);
32 public Set findInvariants(Set vars) {
33 if (isInvariant(vars)) {
38 Set ls=left.findInvariants(vars);
40 ls.addAll(intindex.findInvariants(vars));
41 Expr indexbound=((ArrayDescriptor)this.fd).getIndexBound();
42 ls.addAll(indexbound.findInvariants(vars));
43 if ((!(intindex instanceof IntegerLiteralExpr))||
44 ((IntegerLiteralExpr) intindex).getValue() != 0) {
45 FieldDescriptor fd=this.fd;
46 if (fd instanceof ArrayDescriptor)
47 fd=((ArrayDescriptor)fd).getField();
48 Expr basesize = fd.getBaseSizeExpr();
49 ls.addAll(basesize.findInvariants(vars));
57 public boolean isSafe() {
61 FieldDescriptor tmpfd=fd;
63 if (tmpfd.getPtr()) // Pointers cound be invalid
66 if (tmpfd instanceof ArrayDescriptor) {
67 Expr arrayindex=((ArrayDescriptor)tmpfd).getIndexBound();
68 if (index instanceof IntegerLiteralExpr&&arrayindex instanceof IntegerLiteralExpr) {
69 int indexvalue=((IntegerLiteralExpr)index).getValue();
70 int arrayindexvalue=((IntegerLiteralExpr)arrayindex).getValue();
71 if (indexvalue>=0&&indexvalue<arrayindexvalue)
74 return false; // Otherwise, arrays could be out of bounds
79 public Set freeVars() {
80 Set lset=left.freeVars();
83 iset=intindex.freeVars();
92 static int memoryindents = 0;
94 public static void generate_memory_endblocks(CodeWriter cr) {
95 while (memoryindents > 0) {
104 TypeDescriptor fieldtype;
107 public String name() {
108 String name=left.name()+"."+field;
110 name+="["+index.name()+"]";
114 public void findmatch(Descriptor d, Set s) {
119 intindex.findmatch(d,s);
122 public Set useDescriptor(Descriptor d) {
123 HashSet newset=new HashSet();
126 newset.addAll(left.useDescriptor(d));
128 newset.addAll(intindex.useDescriptor(d));
132 public boolean usesDescriptor(Descriptor d) {
135 return left.usesDescriptor(d)||((intindex!=null)&&intindex.usesDescriptor(d));
138 public boolean equals(Map remap, Expr e) {
139 if (e==null||!(e instanceof DotExpr))
141 DotExpr de=(DotExpr)e;
142 if (!de.field.equals(field))
147 } else if (!index.equals(remap,de.index))
149 if (!left.equals(remap,de.left))
155 public Set getRequiredDescriptors() {
156 Set v = left.getRequiredDescriptors();
158 if (intindex != null) {
159 v.addAll(intindex.getRequiredDescriptors());
164 public Expr getExpr() {
168 public FieldDescriptor getField() {
172 public Expr getIndex() {
176 public void generate(CodeWriter writer, VarDescriptor dest) {
177 VarDescriptor leftd = VarDescriptor.makeNew("left");
179 if (writer.getInvariantValue()!=null&&
180 writer.getInvariantValue().isInvariant(this)) {
181 writer.addDeclaration(getType().getGenerateType().getSafeSymbol().toString(), dest.getSafeSymbol());
182 writer.outputline(dest.getSafeSymbol()+"="+writer.getInvariantValue().getValue(this).getSafeSymbol()+";");
183 writer.outputline("maybe="+writer.getInvariantValue().getMaybe(this).getSafeSymbol()+";");
187 writer.output("/* " + leftd.getSafeSymbol() + " <-- ");
188 left.prettyPrint(writer);
189 writer.outputline("*/");
191 left.generate(writer, leftd);
193 writer.output("/* " + leftd.getSafeSymbol() + " = ");
194 left.prettyPrint(writer);
195 writer.outputline("*/");
197 StructureTypeDescriptor struct = (StructureTypeDescriptor) left.getType();
200 // #ATTN#: getOffsetExpr needs to be called with the fielddescriptor object that is in the vector list
201 // this means that if the field is an arraydescriptor you have to call getOffsetExpr with the array
202 // descriptor not the underlying field descriptor
204 /* we calculate the offset in bits */
206 offsetbits = struct.getOffsetExpr(fd);
208 FieldDescriptor fd=this.fd;
209 if (fd instanceof ArrayDescriptor)
210 fd=((ArrayDescriptor)fd).getField();
211 boolean doboundscheck=true;
212 boolean performedboundscheck=false;
214 writer.addDeclaration(getType().getGenerateType().toString(),dest.getSafeSymbol());
215 writer.outputline(dest.getSafeSymbol()+"=0;");
217 if (intindex != null) {
218 if (intindex instanceof IntegerLiteralExpr && ((IntegerLiteralExpr) intindex).getValue() == 0) {
219 /* short circuit for constant 0 */
221 Expr basesize = fd.getBaseSizeExpr();
223 VarDescriptor indexvd=VarDescriptor.makeNew("index");
224 indexvd.setType(ReservedTypeDescriptor.INT);
225 writer.getSymbolTable().add(indexvd);
227 writer.output("/* " + indexvd.getSafeSymbol() + " <-- ");
229 intindex.prettyPrint(writer);
230 writer.outputline("*/");
231 intindex.generate(writer, indexvd);
232 writer.output("/* " + indexvd.getSafeSymbol() + " = ");
233 intindex.prettyPrint(writer);
234 writer.outputline("*/");
235 Expr indexbound=((ArrayDescriptor)this.fd).getIndexBound();
236 VarDescriptor indexboundvd=VarDescriptor.makeNew("indexbound");
238 indexbound.generate(writer,indexboundvd);
240 writer.outputline("if ("+indexvd.getSafeSymbol()+">=0 &&"+indexvd.getSafeSymbol()+"<"+indexboundvd.getSafeSymbol()+")");
242 VarExpr indexve=new VarExpr(indexvd);
243 offsetbits = new OpExpr(Opcode.ADD, offsetbits, new OpExpr(Opcode.MULT, basesize, indexve));
245 performedboundscheck=true;
247 offsetbits = new OpExpr(Opcode.ADD, offsetbits, new OpExpr(Opcode.MULT, basesize, intindex));
251 final SymbolTable st = writer.getSymbolTable();
252 TypeDescriptor td2 = offsetbits.typecheck(new SemanticAnalyzer() {
253 public IRErrorReporter getErrorReporter() { throw new IRException("badness"); }
254 public SymbolTable getSymbolTable() { return st; }
258 throw new IRException();
259 } else if (td2 != ReservedTypeDescriptor.INT) {
260 throw new IRException();
263 boolean dotypecheck = false;
265 VarDescriptor ob = VarDescriptor.makeNew("offsetinbits");
266 writer.output("/* " + ob.getSafeSymbol() + " <-- ");
267 offsetbits.prettyPrint(writer);
268 writer.outputline("*/");
269 offsetbits.generate(writer, ob);
270 writer.output("/* " + ob.getSafeSymbol() + " = ");
271 offsetbits.prettyPrint(writer);
272 writer.outputline("*/");
274 /* derive offset in bytes */
275 VarDescriptor offset = VarDescriptor.makeNew("offset");
276 writer.addDeclaration("int", offset.getSafeSymbol());
277 writer.outputline(offset.getSafeSymbol() + " = " + ob.getSafeSymbol() + " >> 3;");
279 if (fd.getType() instanceof ReservedTypeDescriptor && !fd.getPtr()) {
280 VarDescriptor shift = VarDescriptor.makeNew("shift");
281 writer.addDeclaration("int", shift.getSafeSymbol());
282 writer.outputline(shift.getSafeSymbol() + " = " + ob.getSafeSymbol() +
283 " - (" + offset.getSafeSymbol() + " << 3);");
284 int mask = bitmask(((IntegerLiteralExpr)fd.getType().getSizeExpr()).getValue());
286 /* type var = ((*(int *) (base + offset)) >> shift) & mask */
287 writer.outputline("if ("+leftd.getSafeSymbol()+")");
288 writer.outputline(dest.getSafeSymbol() + " = ((*(int *)" +
289 "(" + leftd.getSafeSymbol() + " + " + offset.getSafeSymbol() + ")) " +
290 " >> " + shift.getSafeSymbol() + ") & 0x" + Integer.toHexString(mask) + ";");
291 writer.outputline("else maybe=1;");
292 } else { /* a structure address or a ptr */
293 String ptr = fd.getPtr() ? "*(int *)" : "";
294 /* type var = [*(int *)] (base + offset) */
295 writer.outputline("if ("+leftd.getSafeSymbol()+")");
297 writer.outputline(dest.getSafeSymbol() +
298 " = " + ptr + "(" + leftd.getSafeSymbol() + " + " + offset.getSafeSymbol() + ");");
300 writer.outputline("if ("+dest.getSafeSymbol()+")");
302 VarDescriptor typevar=VarDescriptor.makeNew("typechecks");
303 if (DOMEMCHECKS&&(!DOTYPECHECKS)) {
304 writer.addDeclaration("bool", typevar.getSafeSymbol());
305 writer.outputline(typevar.getSafeSymbol()+"=assertvalidmemory(" + dest.getSafeSymbol() + ", " + this.td.getId() + ");");
307 } else if (DOTYPECHECKS) {
308 writer.addDeclaration("bool", typevar.getSafeSymbol());
309 writer.outputline(typevar.getSafeSymbol()+"=assertvalidtype(" + dest.getSafeSymbol() + ", " + this.td.getId() + ");");
312 if (DOTYPECHECKS||DOMEMCHECKS) {
313 writer.outputline("if (!"+typevar.getSafeSymbol()+")");
315 writer.outputline(dest.getSafeSymbol()+"=0;");
317 writer.outputline(ptr + "(" + leftd.getSafeSymbol() + " + " + offset.getSafeSymbol() + ")=0;");
324 writer.outputline("else maybe=1;");
326 if (performedboundscheck) {
328 writer.outputline(" else ");
330 writer.outputline(dest.getSafeSymbol()+"=0;");
331 writer.outputline("maybe=1;");
332 if (!Compiler.REPAIR)
333 writer.outputline("printf(\"Array Index Out of Bounds\");");
338 private int bitmask(int bits) {
341 for (int i = 0; i < bits; i++) {
349 public void prettyPrint(PrettyPrinter pp) {
350 left.prettyPrint(pp);
351 pp.output("." + field);
354 index.prettyPrint(pp);
359 public boolean isValue(TypeDescriptor td) {
360 FieldDescriptor tmpfd=fd;
361 if (tmpfd instanceof ArrayDescriptor)
362 tmpfd=((ArrayDescriptor)tmpfd).getField();
363 return (tmpfd.getPtr()||(tmpfd.getType() instanceof ReservedTypeDescriptor));
366 public boolean isPtr() {
367 FieldDescriptor tmpfd=fd;
368 if (tmpfd instanceof ArrayDescriptor)
369 tmpfd=((ArrayDescriptor)tmpfd).getField();
370 return tmpfd.getPtr();
373 boolean typechecked=false;
374 public TypeDescriptor typecheck(SemanticAnalyzer sa) {
377 else typechecked=true;
378 TypeDescriptor lefttype = left.typecheck(sa);
379 TypeDescriptor indextype = index == null ? null : index.typecheck(sa);
382 /* finished typechecking...so we can fill the fields in */
383 StructureTypeDescriptor struct = (StructureTypeDescriptor) left.getType();
384 FieldDescriptor fd = struct.getField(field);
385 LabelDescriptor ld = struct.getLabel(field);
386 if (ld != null) { /* label */
388 fieldtype = ld.getType(); // d.s ==> Superblock, while, d.b ==> Block
391 assert intindex == null;
392 intindex = ld.getIndex();
395 throw new Error("Null fd for: "+field);
397 fieldtype = fd.getType();
401 if (fieldtype instanceof MissingTypeDescriptor)
402 throw new Error(fieldtype.getSymbol()+" type undefined!");
405 if ((lefttype == null) || (index != null && indextype == null)) {
409 if (indextype != null) {
410 if (indextype != ReservedTypeDescriptor.INT) {
411 sa.getErrorReporter().report(null, "Index must be of type 'int' not '" + indextype.getSymbol() + "'");
416 if (lefttype instanceof StructureTypeDescriptor) {
417 StructureTypeDescriptor struct = (StructureTypeDescriptor) lefttype;
418 FieldDescriptor fd = struct.getField(field);
419 LabelDescriptor ld = struct.getLabel(field);
421 if (fd != null) { /* field */
424 if (indextype == null && fd instanceof ArrayDescriptor) {
425 sa.getErrorReporter().report(null, "Must specify an index what accessing array field '" + struct.getSymbol() + "." + fd.getSymbol() + "'");
427 } else if (indextype != null && !(fd instanceof ArrayDescriptor)) {
428 sa.getErrorReporter().report(null, "Cannot specify an index when accessing non-array field '" + struct.getSymbol() + "." + fd.getSymbol() + "'");
432 this.td = fd.getType();
433 } else if (ld != null) { /* label */
437 sa.getErrorReporter().report(null, "A label cannot be accessed as an array");
441 this.td = ld.getType();
443 sa.getErrorReporter().report(null, "No such field or label '" + field + "' in structure '" + struct.getSymbol() + "'");
447 /* we promote bit, byte and short to integer types */
448 if (this.td == ReservedTypeDescriptor.BIT ||
449 this.td == ReservedTypeDescriptor.BYTE ||
450 this.td == ReservedTypeDescriptor.SHORT) {
451 this.td = ReservedTypeDescriptor.INT;
456 sa.getErrorReporter().report(null, "Left hand side of . expression must be a structure type, not '" + lefttype.getSymbol() + "'");