summaryrefslogtreecommitdiff
path: root/Build/source/utils/asymptote/stm.cc
blob: b45e6f98e4e40582dfe1789549727f8521a6c0f7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
/*****
 * stm.cc
 * Andy Hammerlindl 2002/8/30
 *
 * Statements are everything in the language that do something on their
 * own.  Statements are different from declarations in that statements
 * do not modify the environment.  Translation of a statement puts the
 * stack code to run it into the instruction stream.
 *****/

#include <fstream>
#include "errormsg.h"
#include "settings.h"
#include "coenv.h"
#include "exp.h"
#include "stm.h"

#include "symbol.h"
#include "opsymbols.h"

namespace absyntax {

using namespace trans;
using namespace types;

void stm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"stm",indent);
}


void emptyStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"emptyStm",indent);
}


void blockStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"blockStm",indent);

  base->prettyprint(out, indent+1);
}


void expStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"expStm",indent);

  body->prettyprint(out, indent+1);
}

void baseExpTrans(coenv &e, exp *expr)
{
  types::ty_kind kind = expr->trans(e)->kind;
  if (kind != types::ty_void)
    // Remove any value it puts on the stack.
    e.c.encodePop();
}

void expStm::trans(coenv &e) {
  baseExpTrans(e, body);
}

// For an object such as currentpicture, write 'picture currentpicture' to
// give some information.  Only do this when the object has a name.
void tryToWriteTypeOfExp(types::ty *t, exp *body)
{
  symbol name=body->getName();
  if (!name)
    return;

  overloaded *set = dynamic_cast<overloaded *>(t);
  if (set)
    for(ty_vector::iterator ot=set->sub.begin(); ot!=set->sub.end(); ++ot)
      tryToWriteTypeOfExp(*ot, body);
  else {
    cout << "<";
    t->printVar(cout, name);
    cout << ">" << endl;
  }
}
  
// From dec.cc:
varEntry *makeVarEntry(position pos, coenv &e, record *r, types::ty *t);

void storeExp(coenv &e, types::ty *t, exp *expr) {
  assert(t->kind != ty_error);
  assert(t->kind != ty_void);
  assert(t->kind != ty_overloaded);

  expr->transAsType(e, t);

  // Store the value in a new variable of the proper type.
  varEntry *v = makeVarEntry(expr->getPos(), e, 0, t);
  e.e.addVar(symbol::trans("operator answer"), v);
  v->getLocation()->encode(WRITE, expr->getPos(), e.c);
  e.c.encodePop();
}

void storeAndWriteExp(coenv &e, types::ty *t, exp *expr) {
  storeExp(e, t, expr);

  position pos=expr->getPos();
  baseExpTrans(e, new callExp(pos, new nameExp(pos, "write"),
                                   new nameExp(pos, "operator answer")));
}

void tryToWriteExp(coenv &e, exp *expr)
{
  position pos=expr->getPos();
  types::ty *t=expr->cgetType(e);

  if(!t) return;
  
  // If the original expression is bad, just print the errors.
  // If it is a function which returns void, just call the function.
  if (t->kind == ty_error || t->kind == ty_void) {
    baseExpTrans(e, expr);
    return;
  }

  exp *callee=new nameExp(pos, symbol::trans("write"));
  exp *call=new callExp(pos, callee, expr);

  types::ty *ct=call->getType(e);
  if (ct->kind == ty_error || ct->kind == ty_overloaded) {
    if (t->kind == ty_overloaded) {
      // Translate the expr in order to print the ambiguity error first.
      expr->trans(e);
      em.sync();
      assert(em.errors());
      
      // Then, write out all of the types.
      tryToWriteTypeOfExp(t, expr);
    }
    else {
      // Write the type of the expression and, since it is unique, assign it to
      // 'operator answer' even though its value isn't printed.
      tryToWriteTypeOfExp(t, expr);
      storeExp(e, t, expr);
    }
  }
  else if (t->kind == ty_overloaded) {
    // If the exp is overloaded, but the act of writing makes it
    // unambiguous, add a suffix to the output to warn the user of this.
    exp *suffix=new nameExp(pos,
                            symbol::trans("overloadedMessage"));
    exp *callWithSuffix=new callExp(pos,
                                    callee, expr, suffix);

    if (callWithSuffix->getType(e)->kind != ty_error)
      baseExpTrans(e, callWithSuffix);
    else
      baseExpTrans(e, call);
  }
  else {
    // Interactive writing can proceed normally.
    storeAndWriteExp(e, t, expr);
  }
}

void expStm::interactiveTrans(coenv &e)
{
  // First check if it is the kind of expression that should be written.
  if (body->writtenToPrompt() && 
      settings::getSetting<bool>("interactiveWrite"))
    tryToWriteExp(e, body);
  else
    baseExpTrans(e, body);
}


void ifStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"ifStm",indent);

  test->prettyprint(out, indent+1);
  onTrue->prettyprint(out, indent+1);
  if (onFalse)
    onFalse->prettyprint(out, indent+1);
}

void ifStm::trans(coenv &e)
{
  label elseLabel = e.c.fwdLabel();
  label end = e.c.fwdLabel();

  test->transConditionalJump(e, false, elseLabel);

  onTrue->markTrans(e);
  
  if (onFalse) {
    // Encode the jump around the 'else' clause at the end of the 'if' clause
    e.c.useLabel(inst::jmp,end);

    e.c.defLabel(elseLabel);
    onFalse->markTrans(e);
  } else {
    e.c.defLabel(elseLabel);
  }


  e.c.defLabel(end);
}


void transLoopBody(coenv &e, stm *body) {
  // The semantics of the language are defined so that any variable declared
  // inside a loop are new variables for each iteration of the loop.  For
  // instance, the code 
  //
  //     int f();
  //     for (int i = 0; i < 10; ++i) {
  //       int j=10*i;
  //       if (i == 5)
  //         f = new int() { return j; };
  //     }
  //     write(f());
  //
  // will write 50.  This is implemented by allocating a new frame for each
  // iteration.  However, this can have a big performance hit, so we first
  // translate the code without the frame, check if it needed the closure, and
  // rewrite the code if necessary.

  label start = e.c.defNewLabel();

  // Encode a no-op, in case we need to jump over the default implementation
  // to a special case.
  e.c.encode(inst::nop);

  body->markTrans(e);

  // Don't re-translate if there were errors.
  if (em.errors())
    return;

  if (e.c.usesClosureSinceLabel(start)){
    // Jump over the old section.
    label end = e.c.defNewLabel();
    e.c.encodePatch(start, end);

    // Let coder know that break and continue need to pop the frame.
    e.c.loopPushesFrame();

    e.c.encodePushFrame();
    body->markTrans(e);
    e.c.encodePopFrame();
  }
}

void whileStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"whileStm",indent);

  test->prettyprint(out, indent+1);
  body->prettyprint(out, indent+1);
}

void whileStm::trans(coenv &e)
{
  label end = e.c.fwdLabel();
  label start = e.c.defNewLabel();
  e.c.pushLoop(start, end);

  test->transConditionalJump(e, false, end);

  transLoopBody(e,body);

  e.c.useLabel(inst::jmp,start);
  e.c.defLabel(end);

  e.c.popLoop();
}


void doStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"doStm",indent);

  body->prettyprint(out, indent+1);
  test->prettyprint(out, indent+1);
}

void doStm::trans(coenv &e)
{
  label testLabel = e.c.fwdLabel();
  label end = e.c.fwdLabel();
  e.c.pushLoop(testLabel, end);
 
  label start = e.c.defNewLabel();

  transLoopBody(e,body);  
  
  e.c.defLabel(testLabel);

  test->transConditionalJump(e, true, start);

  e.c.defLabel(end);

  e.c.popLoop();
}


void forStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"forStm",indent);

  if (init) init->prettyprint(out, indent+1);
  if (test) test->prettyprint(out, indent+1);
  if (update) update->prettyprint(out, indent+1);
  body->prettyprint(out, indent+1);
}

void forStm::trans(coenv &e)
{
  // Any vardec in the initializer needs its own scope.
  e.e.beginScope();
  if (init)
    init->markTrans(e);

  label ctarget = e.c.fwdLabel();
  label end = e.c.fwdLabel();
  e.c.pushLoop(ctarget, end);

  label start = e.c.defNewLabel();
  if(test) {
    test->transConditionalJump(e, false, end);
  }

  transLoopBody(e,body);

  e.c.defLabel(ctarget);
  
  if (update)
    update->markTrans(e);
  e.c.useLabel(inst::jmp,start);

  e.c.defLabel(end);

  e.c.popLoop();

  e.e.endScope();
}

void extendedForStm::prettyprint(ostream &out, Int indent)
{
  prettyindent(out, indent);
  out << "extendedForStm: '" << var << "'\n";

  start->prettyprint(out, indent+1);
  set->prettyprint(out, indent+1);
  body->prettyprint(out, indent+1);
}

void extendedForStm::trans(coenv &e) {
  // Translate into the syntax:
  //
  // start[] a = set;
  // for (int i=0; i < a.length; ++i) {
  //   start var=a[i];
  //   body
  // }

  position pos=getPos();

  // Use gensyms for the variable names so as not to pollute the namespace.
  symbol a=symbol::gensym("a");
  symbol i=symbol::gensym("i");

  // Get the start type.  Handle type inference as a special case.
  types::ty *t = start->trans(e, true);
  if (t->kind == types::ty_inferred) {

    // First ensure the array expression is an unambiguous array.
    types::ty *at = set->cgetType(e);
    if (at->kind != ty_array) {
      em.error(set->getPos());
      em << "expression is not an array of inferable type";
      
      // On failure, don't bother trying to translate the loop.
      return;
    }

    // var a=set;
    tyEntryTy tet(pos, primInferred());
    decid dec1(pos, new decidstart(pos, a), set);
    vardec(pos, &tet, &dec1).trans(e);
  }
  else {
    // start[] a=set;
    arrayTy at(pos, start, new dimensions(pos));
    decid dec1(pos, new decidstart(pos, a), set);
    vardec(pos, &at, &dec1).trans(e);
  }

  // { start var=a[i]; body }
  block b(pos);
  decid dec2(pos,
             new decidstart(pos, var), 
             new subscriptExp(pos, new nameExp(pos, a),
                              new nameExp(pos, i)));
  b.add(new vardec(pos, start, &dec2));
  b.add(body);

  // for (int i=0; i < a.length; ++i)
  //   <block>
  forStm(pos,
         new vardec(pos, new tyEntryTy(pos, primInt()),
                         new decid(pos,
                                   new decidstart(pos, i),
                                   new intExp(pos, 0))),
         new binaryExp(pos,
                       new nameExp(pos, i),
                       SYM_LT,
                       new nameExp(pos,
                                   new qualifiedName(pos,
                                                     new simpleName(pos, a),
                                                     symbol::trans("length")))),
         new expStm(pos, new prefixExp(pos, new nameExp(pos, i), SYM_PLUS)),
         new blockStm(pos, &b)).trans(e);
}
                              

void breakStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"breakStm",indent);
}

void breakStm::trans(coenv &e)
{
  if (!e.c.encodeBreak()) {
    em.error(getPos());
    em << "break statement outside of a loop";
  }
}


void continueStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out,"continueStm",indent);
}

void continueStm::trans(coenv &e)
{
  if (!e.c.encodeContinue()) {
    em.error(getPos()); 
    em << "continue statement outside of a loop";
  }
}


void returnStm::prettyprint(ostream &out, Int indent)
{
  prettyname(out, "returnStm",indent);

  if (value)
    value->prettyprint(out, indent+1);
}

void returnStm::trans(coenv &e)
{
  types::ty *t = e.c.getReturnType();

  if (t->kind == ty_void) {
    if (value) {
      em.error(getPos());
      em << "function cannot return a value";
    }
    if (e.c.isRecord())
      e.c.encode(inst::pushclosure);
  }
  else {
    if (value) {
      value->transToType(e, t);
    }
    else {
      em.error(getPos());
      em << "function must return a value";
    }
  }

  // NOTE: Currently, a return statement in a module definition will end
  // the initializer.  Should this be allowed?
  e.c.encode(inst::ret);
}


void stmExpList::prettyprint(ostream &out, Int indent)
{
  prettyname(out, "stmExpList",indent);

  for (mem::list<stm *>::iterator p = stms.begin(); p != stms.end(); ++p)
    (*p)->prettyprint(out, indent+1);
}

void stmExpList::trans(coenv &e)
{
  for (mem::list<stm *>::iterator p = stms.begin(); p != stms.end(); ++p)
    (*p)->markTrans(e);
}


} // namespace absyntax