1// RUN: %clang_cc1 -Wunused-variable -analyze -analyzer-checker=core,deadcode.DeadStores,alpha.deadcode.IdempotentOperations -fblocks -verify -Wno-unreachable-code -analyzer-opt-analyze-nested-blocks %s
2// RUN: %clang_cc1 -Wunused-variable -analyze -analyzer-checker=core,deadcode.DeadStores,alpha.deadcode.IdempotentOperations -analyzer-store=region -analyzer-constraints=range -fblocks -verify -Wno-unreachable-code -analyzer-opt-analyze-nested-blocks %s
3
4void f1() {
5  int k, y; // expected-warning{{unused variable 'k'}} expected-warning{{unused variable 'y'}}
6  int abc=1;
7  long idx=abc+3*5; // expected-warning {{never read}} expected-warning{{unused variable 'idx'}}
8}
9
10void f2(void *b) {
11 char *c = (char*)b; // no-warning
12 char *d = b+1; // expected-warning {{never read}} expected-warning{{unused variable 'd'}}
13 printf("%s", c); // expected-warning{{implicitly declaring library function 'printf' with type 'int (const char *, ...)'}} \
14 // expected-note{{please include the header <stdio.h> or explicitly provide a declaration for 'printf'}}
15}
16
17int f();
18
19void f3() {
20  int r;
21  if ((r = f()) != 0) { // no-warning
22    int y = r; // no-warning
23    printf("the error is: %d\n", y);
24  }
25}
26
27void f4(int k) {
28
29  k = 1;
30
31  if (k)
32    f1();
33
34  k = 2;  // expected-warning {{never read}}
35}
36
37void f5() {
38
39  int x = 4; // no-warning
40  int *p = &x; // expected-warning{{never read}} expected-warning{{unused variable 'p'}}
41
42}
43
44//
45int f6() {
46
47  int x = 4;
48  ++x; // no-warning
49  return 1;
50}
51
52int f7(int *p) {
53  // This is allowed for defensive programming.
54  p = 0; // no-warning
55  return 1;
56}
57
58int f7b(int *p) {
59  // This is allowed for defensive programming.
60  p = (0); // no-warning
61  return 1;
62}
63
64int f7c(int *p) {
65  // This is allowed for defensive programming.
66  p = (void*) 0; // no-warning
67  return 1;
68}
69
70int f7d(int *p) {
71  // This is allowed for defensive programming.
72  p = (void*) (0); // no-warning
73  return 1;
74}
75
76// Don't warn for dead stores in nested expressions.  We have yet
77// to see a real bug in this scenario.
78int f8(int *p) {
79  extern int *baz();
80  if ((p = baz())) // no-warning
81    return 1;
82  return 0;
83}
84
85int f9() {
86  int x = 4;
87  x = x + 10; // expected-warning{{never read}}
88  return 1;
89}
90
91int f10() {
92  int x = 4;
93  x = 10 + x; // expected-warning{{never read}}
94  return 1;
95}
96
97int f11() {
98  int x = 4;
99  return x++; // expected-warning{{never read}}
100}
101
102int f11b() {
103  int x = 4;
104  return ((((++x)))); // no-warning
105}
106
107int f12a(int y) {
108  int x = y;  // expected-warning{{unused variable 'x'}}
109  return 1;
110}
111int f12b(int y) {
112  int x __attribute__((unused)) = y;  // no-warning
113  return 1;
114}
115int f12c(int y) {
116  // Allow initialiation of scalar variables by parameters as a form of
117  // defensive programming.
118  int x = y;  // no-warning
119  x = 1;
120  return x;
121}
122
123// Filed with PR 2630.  This code should produce no warnings.
124int f13(void)
125{
126  int a = 1;
127  int b, c = b = a + a;
128
129  if (b > 0)
130    return (0);
131
132  return (a + b + c);
133}
134
135// Filed with PR 2763.
136int f14(int count) {
137  int index, nextLineIndex;
138  for (index = 0; index < count; index = nextLineIndex+1) {
139    nextLineIndex = index+1;  // no-warning
140    continue;
141  }
142  return index;
143}
144
145// Test case for <rdar://problem/6248086>
146void f15(unsigned x, unsigned y) {
147  int count = x * y;   // no-warning
148  int z[count]; // expected-warning{{unused variable 'z'}}
149}
150
151// Don't warn for dead stores in nested expressions.  We have yet
152// to see a real bug in this scenario.
153int f16(int x) {
154  x = x * 2;
155  x = sizeof(int [x = (x || x + 1) * 2]) // expected-warning{{The left operand to '+' is always 0}} expected-warning{{The left operand to '*' is always 1}}
156      ? 5 : 8;
157  return x;
158}
159
160// Self-assignments should not be flagged as dead stores.
161void f17() {
162  int x = 1;
163  x = x;
164}
165
166// <rdar://problem/6506065>
167// The values of dead stores are only "consumed" in an enclosing expression
168// what that value is actually used.  In other words, don't say "Although the
169// value stored to 'x' is used...".
170int f18() {
171   int x = 0; // no-warning
172   if (1)
173      x = 10;  // expected-warning{{Value stored to 'x' is never read}}
174   while (1)
175      x = 10;  // expected-warning{{Value stored to 'x' is never read}}
176   // unreachable.
177   do
178      x = 10;   // no-warning
179   while (1);
180   return (x = 10); // no-warning
181}
182
183int f18_a() {
184   int x = 0; // no-warning
185   return (x = 10); // no-warning
186}
187
188void f18_b() {
189   int x = 0; // no-warning
190   if (1)
191      x = 10;  // expected-warning{{Value stored to 'x' is never read}}
192}
193
194void f18_c() {
195  int x = 0;
196  while (1)
197     x = 10;  // expected-warning{{Value stored to 'x' is never read}}
198}
199
200void f18_d() {
201  int x = 0; // no-warning
202  do
203     x = 10;   // expected-warning{{Value stored to 'x' is never read}}
204  while (1);
205}
206
207// PR 3514: false positive `dead initialization` warning for init to global
208//  http://llvm.org/bugs/show_bug.cgi?id=3514
209extern const int MyConstant;
210int f19(void) {
211  int x = MyConstant;  // no-warning
212  x = 1;
213  return x;
214}
215
216int f19b(void) { // This case is the same as f19.
217  const int MyConstant = 0;
218  int x = MyConstant; // no-warning
219  x = 1;
220  return x;
221}
222
223void f20(void) {
224  int x = 1; // no-warning
225#pragma unused(x)
226}
227
228void halt() __attribute__((noreturn));
229int f21() {
230  int x = 4;
231
232  x = x + 1; // expected-warning{{never read}}
233  if (1) {
234    halt();
235    (void)x;
236  }
237  return 1;
238}
239
240int j;
241void f22() {
242  int x = 4;
243  int y1 = 4;
244  int y2 = 4;
245  int y3 = 4;
246  int y4 = 4;
247  int y5 = 4;
248  int y6 = 4;
249  int y7 = 4;
250  int y8 = 4;
251  int y9 = 4;
252  int y10 = 4;
253  int y11 = 4;
254  int y12 = 4;
255  int y13 = 4;
256  int y14 = 4;
257  int y15 = 4;
258  int y16 = 4;
259  int y17 = 4;
260  int y18 = 4;
261  int y19 = 4;
262  int y20 = 4;
263
264  x = x + 1; // expected-warning{{never read}}
265  ++y1;
266  ++y2;
267  ++y3;
268  ++y4;
269  ++y5;
270  ++y6;
271  ++y7;
272  ++y8;
273  ++y9;
274  ++y10;
275  ++y11;
276  ++y12;
277  ++y13;
278  ++y14;
279  ++y15;
280  ++y16;
281  ++y17;
282  ++y18;
283  ++y19;
284  ++y20;
285
286  switch (j) {
287  case 1:
288    if (0)
289      (void)x;
290    if (1) {
291      (void)y1;
292      return;
293    }
294    (void)x;
295    break;
296  case 2:
297    if (0)
298      (void)x;
299    else {
300      (void)y2;
301      return;
302    }
303    (void)x;
304    break;
305  case 3:
306    if (1) {
307      (void)y3;
308      return;
309    } else
310      (void)x;
311    (void)x;
312  break;
313  case 4:
314    0 ? : ((void)y4, ({ return; }));
315    (void)x;
316    break;
317  case 5:
318    1 ? : (void)x;
319    0 ? (void)x : ((void)y5, ({ return; }));
320    (void)x;
321    break;
322  case 6:
323    1 ? ((void)y6, ({ return; })) : (void)x;
324    (void)x;
325    break;
326  case 7:
327    (void)(0 && x);
328    (void)y7;
329    (void)(0 || (y8, ({ return; }), 1));  // expected-warning {{expression result unused}}
330    (void)x;
331    break;
332  case 8:
333    (void)(1 && (y9, ({ return; }), 1));  // expected-warning {{expression result unused}}
334    (void)x;
335    break;
336  case 9:
337    (void)(1 || x);
338    (void)y10;
339    break;
340  case 10:
341    while (0) {
342      (void)x;
343    }
344    (void)y11;
345    break;
346  case 11:
347    while (1) {
348      (void)y12;
349    }
350    (void)x;
351    break;
352  case 12:
353    do {
354      (void)y13;
355    } while (0);
356    (void)y14;
357    break;
358  case 13:
359    do {
360      (void)y15;
361    } while (1);
362    (void)x;
363    break;
364  case 14:
365    for (;;) {
366      (void)y16;
367    }
368    (void)x;
369    break;
370  case 15:
371    for (;1;) {
372      (void)y17;
373    }
374    (void)x;
375    break;
376  case 16:
377    for (;0;) {
378      (void)x;
379    }
380    (void)y18;
381    break;
382  case 17:
383    __builtin_choose_expr(0, (void)x, ((void)y19, ({ return; })));
384    (void)x;
385    break;
386  case 19:
387    __builtin_choose_expr(1, ((void)y20, ({ return; })), (void)x);
388    (void)x;
389    break;
390  }
391}
392
393void f23_aux(const char* s);
394void f23(int argc, char **argv) {
395  int shouldLog = (argc > 1); // no-warning
396  ^{
397     if (shouldLog) f23_aux("I did too use it!\n");
398     else f23_aux("I shouldn't log.  Wait.. d'oh!\n");
399  }();
400}
401
402void f23_pos(int argc, char **argv) {
403  int shouldLog = (argc > 1); // expected-warning{{Value stored to 'shouldLog' during its initialization is never read}} expected-warning{{unused variable 'shouldLog'}}
404  ^{
405     f23_aux("I did too use it!\n");
406  }();
407}
408
409void f24_A(int y) {
410  // FIXME: One day this should be reported as dead since 'z = x + y' is dead.
411  int x = (y > 2); // no-warning
412  ^ {
413      int z = x + y; // expected-warning{{Value stored to 'z' during its initialization is never read}} expected-warning{{unused variable 'z'}}
414  }();
415}
416
417void f24_B(int y) {
418  // FIXME: One day this should be reported as dead since 'x' is just overwritten.
419  __block int x = (y > 2); // no-warning
420  ^{
421    // FIXME: This should eventually be a dead store since it is never read either.
422    x = 5; // no-warning
423  }();
424}
425
426int f24_C(int y) {
427  // FIXME: One day this should be reported as dead since 'x' is just overwritten.
428  __block int x = (y > 2); // no-warning
429  ^{
430    x = 5; // no-warning
431  }();
432  return x;
433}
434
435int f24_D(int y) {
436  __block int x = (y > 2); // no-warning
437  ^{
438    if (y > 4)
439      x = 5; // no-warning
440  }();
441  return x;
442}
443
444// This example shows that writing to a variable captured by a block means that it might
445// not be dead.
446int f25(int y) {
447  __block int x = (y > 2);
448  __block int z = 0;
449  void (^foo)() = ^{ z = x + y; };
450  x = 4; // no-warning
451  foo();
452  return z;
453}
454
455// This test is mostly the same as 'f25', but shows that the heuristic of pruning out dead
456// stores for variables that are just marked '__block' is overly conservative.
457int f25_b(int y) {
458  // FIXME: we should eventually report a dead store here.
459  __block int x = (y > 2);
460  __block int z = 0;
461  x = 4; // no-warning
462  return z;
463}
464
465int f26_nestedblocks() {
466  int z;
467  z = 1;
468  __block int y = 0;
469  ^{
470    int k;
471    k = 1; // expected-warning{{Value stored to 'k' is never read}}
472    ^{
473        y = z + 1;
474     }();
475  }();
476  return y;
477}
478
479// The FOREACH macro in QT uses 'break' statements within statement expressions
480// placed within the increment code of for loops.
481void rdar8014335() {
482  for (int i = 0 ; i != 10 ; ({ break; })) {
483    for ( ; ; ({ ++i; break; })) ;
484    // Note that the next value stored to 'i' is never executed
485    // because the next statement to be executed is the 'break'
486    // in the increment code of the first loop.
487    i = i * 3; // expected-warning{{Value stored to 'i' is never read}} expected-warning{{The left operand to '*' is always 1}}
488  }
489}
490
491// <rdar://problem/8320674> NullStmts followed by do...while() can lead to disconnected CFG
492//
493// This previously caused bogus dead-stores warnings because the body of the first do...while was
494// disconnected from the entry of the function.
495typedef struct { float r; float i; } s_rdar8320674;
496typedef struct { s_rdar8320674 x[1]; } s2_rdar8320674;
497
498void rdar8320674(s_rdar8320674 *z, unsigned y, s2_rdar8320674 *st, int m)
499{
500    s_rdar8320674 * z2;
501    s_rdar8320674 * tw1 = st->x;
502    s_rdar8320674 t;
503    z2 = z + m;
504    do{
505        ; ;
506        do{ (t).r = (*z2).r*(*tw1).r - (*z2).i*(*tw1).i; (t).i = (*z2).r*(*tw1).i + (*z2).i*(*tw1).r; }while(0);
507        tw1 += y;
508        do { (*z2).r=(*z).r-(t).r; (*z2).i=(*z).i-(t).i; }while(0);
509        do { (*z).r += (t).r; (*z).i += (t).i; }while(0);
510        ++z2;
511        ++z;
512    }while (--m);
513}
514
515// Avoid dead stores resulting from an assignment (and use) being unreachable.
516void rdar8405222_aux(int i);
517void rdar8405222() {
518  const int show = 0;
519  int i = 0;
520
521  if (show)
522      i = 5; // no-warning
523
524  if (show)
525    rdar8405222_aux(i);
526}
527
528// Look through chains of assignements, e.g.: int x = y = 0, when employing
529// silencing heuristics.
530int radar11185138_foo() {
531  int x, y;
532  x = y = 0; // expected-warning {{never read}}
533  return y;
534}
535
536int rdar11185138_bar() {
537  int y;
538  int x = y = 0; // no-warning
539  x = 2;
540  y = 2;
541  return x + y;
542}
543
544int *radar11185138_baz() {
545  int *x, *y;
546  x = y = 0; // no-warning
547  return y;
548}
549
550int getInt();
551int *getPtr();
552void testBOComma() {
553  int x0 = (getInt(), 0); // expected-warning{{unused variable 'x0'}}
554  int x1 = (getInt(), getInt()); // expected-warning {{Value stored to 'x1' during its initialization is never read}} // expected-warning{{unused variable 'x1'}}
555  int x2 = (getInt(), getInt(), getInt()); //expected-warning{{Value stored to 'x2' during its initialization is never read}} // expected-warning{{unused variable 'x2'}}
556  int x3;
557  x3 = (getInt(), getInt(), 0); // expected-warning{{Value stored to 'x3' is never read}}
558  int x4 = (getInt(), (getInt(), 0)); // expected-warning{{unused variable 'x4'}}
559  int y;
560  int x5 = (getInt(), (y = 0)); // expected-warning{{unused variable 'x5'}}
561  int x6 = (getInt(), (y = getInt())); //expected-warning {{Value stored to 'x6' during its initialization is never read}} // expected-warning{{unused variable 'x6'}}
562  int x7 = 0, x8 = getInt(); //expected-warning {{Value stored to 'x8' during its initialization is never read}} // expected-warning{{unused variable 'x8'}} // expected-warning{{unused variable 'x7'}}
563  int x9 = getInt(), x10 = 0; //expected-warning {{Value stored to 'x9' during its initialization is never read}} // expected-warning{{unused variable 'x9'}}  // expected-warning{{unused variable 'x10'}}
564  int m = getInt(), mm, mmm; //expected-warning {{Value stored to 'm' during its initialization is never read}} // expected-warning{{unused variable 'm'}} // expected-warning{{unused variable 'mm'}} // expected-warning{{unused variable 'mmm'}}
565  int n, nn = getInt(); //expected-warning {{Value stored to 'nn' during its initialization is never read}} // expected-warning{{unused variable 'n'}} // expected-warning{{unused variable 'nn'}}
566
567  int *p;
568  p = (getPtr(), (int *)0); // no warning
569
570}
571
572