5 public class DotExpr extends Expr {
11 static boolean DOMEMCHECKS=true;
12 static boolean DOTYPECHECKS=false;
13 static boolean DONULL=false;
15 public Set freeVars() {
16 Set lset=left.freeVars();
19 iset=index.freeVars();
28 static int memoryindents = 0;
30 public static void generate_memory_endblocks(CodeWriter cr) {
31 while (memoryindents > 0) {
40 TypeDescriptor fieldtype;
43 public String name() {
44 String name=left.name()+"."+field;
46 name+="["+index.name()+"]";
50 public boolean usesDescriptor(Descriptor d) {
53 return left.usesDescriptor(d)||((intindex!=null)&&intindex.usesDescriptor(d));
56 public boolean equals(Map remap, Expr e) {
57 if (e==null||!(e instanceof DotExpr))
59 DotExpr de=(DotExpr)e;
60 if (!de.field.equals(field))
65 } else if (!index.equals(remap,de.index))
67 if (!left.equals(remap,de.left))
73 public DotExpr(Expr left, String field, Expr index) {
79 public Set getRequiredDescriptors() {
80 Set v = left.getRequiredDescriptors();
83 v.addAll(index.getRequiredDescriptors());
88 public Expr getExpr() {
92 public FieldDescriptor getField() {
96 public Expr getIndex() {
100 public void generate(CodeWriter writer, VarDescriptor dest) {
101 VarDescriptor leftd = VarDescriptor.makeNew("left");
103 writer.output("// " + leftd.getSafeSymbol() + " <-- ");
104 left.prettyPrint(writer);
105 writer.outputline("");
107 left.generate(writer, leftd);
109 writer.output("// " + leftd.getSafeSymbol() + " = ");
110 left.prettyPrint(writer);
111 writer.outputline("");
113 StructureTypeDescriptor struct = (StructureTypeDescriptor) left.getType();
114 Expr intindex = index;
117 // #ATTN#: getOffsetExpr needs to be called with the fielddescriptor obect that is in teh vector list
118 // this means that if the field is an arraydescriptor you have to call getOffsetExpr with the array
119 // descriptor not the underlying field descriptor
121 /* we calculate the offset in bits */
122 offsetbits = struct.getOffsetExpr(fd);
124 if (fd instanceof ArrayDescriptor) {
125 fd = ((ArrayDescriptor) fd).getField();
128 if (intindex != null) {
129 if (intindex instanceof IntegerLiteralExpr && ((IntegerLiteralExpr) intindex).getValue() == 0) {
130 /* short circuit for constant 0 */
132 Expr basesize = fd.getBaseSizeExpr();
133 offsetbits = new OpExpr(Opcode.ADD, offsetbits, new OpExpr(Opcode.MULT, basesize, intindex));
137 final SymbolTable st = writer.getSymbolTable();
138 TypeDescriptor td = offsetbits.typecheck(new SemanticAnalyzer() {
139 public IRErrorReporter getErrorReporter() { throw new IRException("badness"); }
140 public SymbolTable getSymbolTable() { return st; }
144 throw new IRException();
145 } else if (td != ReservedTypeDescriptor.INT) {
146 throw new IRException();
149 boolean dotypecheck = false;
151 if (offsetbits instanceof IntegerLiteralExpr) {
152 int offsetinbits = ((IntegerLiteralExpr) offsetbits).getValue();
153 int offset = offsetinbits >> 3; /* offset in bytes */
155 if (fd.getType() instanceof ReservedTypeDescriptor && !fd.getPtr()) {
156 int shift = offsetinbits - (offset << 3);
157 int mask = bitmask(((IntegerLiteralExpr)fd.getType().getSizeExpr()).getValue());
159 /* type var = ((*(int *) (base + offset)) >> shift) & mask */
160 writer.outputline(getType().getGenerateType() + " "+dest.getSafeSymbol()+"=0;");
161 writer.outputline("if ("+leftd.getSafeSymbol()+")");
162 writer.outputline(dest.getSafeSymbol() + " = ((*(int *)" +
163 "(" + leftd.getSafeSymbol() + " + " + offset + ")) " +
164 " >> " + shift + ") & 0x" + Integer.toHexString(mask) + ";");
165 writer.outputline("else maybe=1;");
166 } else { /* a structure address or a ptr! */
167 String ptr = fd.getPtr() ? "*(int *)" : "";
168 /* type var = [*(int *)] (base + offset) */
169 writer.outputline("int " + dest.getSafeSymbol()+"=0;");
170 writer.outputline("if ("+leftd.getSafeSymbol()+")");
171 writer.outputline(dest.getSafeSymbol() +
172 " = " + ptr + "(" + leftd.getSafeSymbol() + " + " + offset + ");");
173 writer.outputline("else maybe=1;");
175 VarDescriptor typevar=VarDescriptor.makeNew("typechecks");
176 if (DOMEMCHECKS&&(!DOTYPECHECKS)) {
177 writer.outputline("bool "+typevar.getSafeSymbol()+"=assertvalidmemory(" + dest.getSafeSymbol() + ", " + td.getId() + ");");
179 } else if (DOTYPECHECKS) {
180 writer.outputline("bool "+typevar.getSafeSymbol()+"=assertvalidtype(" + dest.getSafeSymbol() + ", " + td.getId() + ");");
182 writer.outputline("if (!"+typevar.getSafeSymbol()+")");
184 writer.outputline(dest.getSafeSymbol()+"=0;");
186 writer.outputline(ptr + "(" + leftd.getSafeSymbol() + " + " + offset + ")=0;");
190 } else { /* offset in bits is an expression that must be generated */
191 VarDescriptor ob = VarDescriptor.makeNew("offsetinbits");
192 writer.output("// " + ob.getSafeSymbol() + " <-- ");
193 offsetbits.prettyPrint(writer);
194 writer.outputline("");
195 offsetbits.generate(writer, ob);
196 writer.output("// " + ob.getSafeSymbol() + " = ");
197 offsetbits.prettyPrint(writer);
198 writer.outputline("");
200 /* derive offset in bytes */
201 VarDescriptor offset = VarDescriptor.makeNew("offset");
202 writer.outputline("int " + offset.getSafeSymbol() + " = " + ob.getSafeSymbol() + " >> 3;");
204 if (fd.getType() instanceof ReservedTypeDescriptor && !fd.getPtr()) {
205 VarDescriptor shift = VarDescriptor.makeNew("shift");
206 writer.outputline("int " + shift.getSafeSymbol() + " = " + ob.getSafeSymbol() +
207 " - (" + offset.getSafeSymbol() + " << 3);");
208 int mask = bitmask(((IntegerLiteralExpr)fd.getType().getSizeExpr()).getValue());
210 /* type var = ((*(int *) (base + offset)) >> shift) & mask */
211 writer.outputline(getType().getGenerateType() + " " + dest.getSafeSymbol()+"=0;");
212 writer.outputline("if ("+leftd.getSafeSymbol()+")");
213 writer.outputline(dest.getSafeSymbol() +
215 "(" + leftd.getSafeSymbol() + " + " + offset.getSafeSymbol() + ")) " +
216 " >> " + shift.getSafeSymbol() + ") & 0x" + Integer.toHexString(mask) + ";");
217 writer.outputline("else maybe=1;");
218 } else { /* a structure address or a ptr */
219 String ptr = fd.getPtr() ? "*(int *)" : "";
220 /* type var = [*(int *)] (base + offset) */
221 writer.outputline("int " + dest.getSafeSymbol() +"=0;");
222 writer.outputline("if ("+leftd.getSafeSymbol()+")");
223 writer.outputline(dest.getSafeSymbol() +
224 " = " + ptr + "(" + leftd.getSafeSymbol() + " + " + offset.getSafeSymbol() + ");");
225 writer.outputline("else maybe=1;");
227 VarDescriptor typevar=VarDescriptor.makeNew("typechecks");
228 if (DOMEMCHECKS&&(!DOTYPECHECKS)) {
229 writer.outputline("bool "+typevar.getSafeSymbol()+"=assertvalidmemory(" + dest.getSafeSymbol() + ", " + td.getId() + ");");
231 } else if (DOTYPECHECKS) {
232 writer.outputline("bool "+typevar.getSafeSymbol()+"=assertvalidtype(" + dest.getSafeSymbol() + ", " + td.getId() + ");");
234 writer.outputline("if (!"+typevar.getSafeSymbol()+")");
236 writer.outputline(dest.getSafeSymbol()+"=0;");
238 writer.outputline(ptr + "(" + leftd.getSafeSymbol() + " + " + offset.getSafeSymbol() + ")=0;");
245 private int bitmask(int bits) {
248 for (int i = 0; i < bits; i++) {
256 public void prettyPrint(PrettyPrinter pp) {
257 left.prettyPrint(pp);
258 pp.output("." + field);
261 index.prettyPrint(pp);
266 public TypeDescriptor typecheck(SemanticAnalyzer sa) {
267 TypeDescriptor lefttype = left.typecheck(sa);
268 TypeDescriptor indextype = index == null ? null : index.typecheck(sa);
271 /* finished typechecking...so we can fill the fields in */
272 StructureTypeDescriptor struct = (StructureTypeDescriptor) left.getType();
273 FieldDescriptor fd = struct.getField(field);
274 LabelDescriptor ld = struct.getLabel(field);
275 if (ld != null) { /* label */
277 fieldtype = ld.getType(); // d.s ==> Superblock, while, d.b ==> Block
280 assert intindex == null;
281 intindex = ld.getIndex();
283 fieldtype = fd.getType();
289 if ((lefttype == null) || (index != null && indextype == null)) {
293 if (indextype != null) {
294 if (indextype != ReservedTypeDescriptor.INT) {
295 sa.getErrorReporter().report(null, "Index must be of type 'int' not '" + indextype.getSymbol() + "'");
300 if (lefttype instanceof StructureTypeDescriptor) {
301 StructureTypeDescriptor struct = (StructureTypeDescriptor) lefttype;
302 FieldDescriptor fd = struct.getField(field);
303 LabelDescriptor ld = struct.getLabel(field);
305 if (fd != null) { /* field */
308 if (indextype == null && fd instanceof ArrayDescriptor) {
309 sa.getErrorReporter().report(null, "Must specify an index what accessing array field '" + struct.getSymbol() + "." + fd.getSymbol() + "'");
311 } else if (indextype != null && !(fd instanceof ArrayDescriptor)) {
312 sa.getErrorReporter().report(null, "Cannot specify an index when accessing non-array field '" + struct.getSymbol() + "." + fd.getSymbol() + "'");
316 this.td = fd.getType();
317 } else if (ld != null) { /* label */
321 sa.getErrorReporter().report(null, "A label cannot be accessed as an array");
325 this.td = ld.getType();
327 sa.getErrorReporter().report(null, "No such field or label '" + field + "' in structure '" + struct.getSymbol() + "'");
331 /* we promote bit, byte and short to integer types */
332 if (this.td == ReservedTypeDescriptor.BIT ||
333 this.td == ReservedTypeDescriptor.BYTE ||
334 this.td == ReservedTypeDescriptor.SHORT) {
335 this.td = ReservedTypeDescriptor.INT;
340 sa.getErrorReporter().report(null, "Left hand side of . expression must be a structure type, not '" + lefttype.getSymbol() + "'");