C++: suppress alerts in tightly bounded loops

cpp/ql/test/query-tests/Likely Bugs/Memory Management/AllocaInLoop/AllocaInLoop.expected

@@ -6,3 +6,12 @@
 | AllocaInLoop1ms.cpp:79:19:79:25 | call to _alloca | Stack allocation is inside a $@ and could lead to stack overflow. | AllocaInLoop1ms.cpp:70:3:87:3 | for(...;...;...) ... | for(...;...;...) ... |
 | AllocaInLoop2.c:39:30:39:35 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | AllocaInLoop2.c:29:5:48:19 | do (...) ... | do (...) ... |
 | AllocaInLoop3.cpp:45:23:45:28 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | AllocaInLoop3.cpp:43:2:49:19 | do (...) ... | do (...) ... |
+| BoundedLoop.cpp:25:5:25:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:24:3:26:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:38:5:38:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:37:3:39:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:55:5:55:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:54:3:59:3 | while (...) ... | while (...) ... |
+| BoundedLoop.cpp:64:5:64:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:63:3:68:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:73:5:73:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:72:3:74:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:97:5:97:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:96:3:98:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:105:5:105:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:104:3:106:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:138:5:138:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:137:3:139:3 | for(...;...;...) ... | for(...;...;...) ... |
+| BoundedLoop.cpp:176:5:176:10 | call to __builtin_alloca | Stack allocation is inside a $@ and could lead to stack overflow. | BoundedLoop.cpp:175:3:177:3 | for(...;...;...) ... | for(...;...;...) ... |

cpp/ql/test/query-tests/Likely Bugs/Memory Management/AllocaInLoop/BoundedLoop.cpp

@@ -0,0 +1,185 @@
+void *__builtin_alloca(unsigned long sz);
+#define alloca __builtin_alloca
+
+void forOnce() {
+  for (struct { bool stop; } state = { 0 }; !state.stop; state.stop = 1) {
+    alloca(100); // GOOD
+  }
+}
+
+void forOnce2() {
+  bool stop;
+  for (stop = 0; !stop; stop = 1) {
+    alloca(100); // GOOD
+  }
+}
+
+void forTwice() {
+  for (int i = 0; i < 2; i++) {
+    alloca(100); // GOOD
+  }
+}
+
+void forEver() {
+  for (;;) {
+    alloca(100); // BAD
+  }
+}
+
+void doTwice() {
+  int i = 0;
+  do {
+    alloca(100); // GOOD
+  } while (++i < 2);
+}
+
+void unknownStartingPoint(int i) {
+  for (; i < 2; i++) {
+    alloca(100); // BAD
+  }
+}
+
+int getInt();
+
+void atMostTwice() {
+  int i = 0;
+  while (!(i >= 2 || getInt())) {
+    i++;
+    alloca(100); // GOOD
+  }
+}
+
+void sometimesIncrement() {
+  int i = 0;
+  while (i < 2) {
+    alloca(100); // BAD
+    if (getInt()) {
+      i++;
+    }
+  }
+}
+
+void upAndDown() {
+  for (int i = 0; i < 2; i++) {
+    alloca(100); // BAD
+    if (getInt()) {
+      i--;
+    }
+  }
+}
+
+void largeBound() {
+  for (int i = 0; i < 10000; i++) {
+    alloca(100); // BAD
+  }
+}
+
+void largeOffset() {
+  int i;
+  if (getInt()) {
+    i = 9998;
+  } else {
+    i = 9997;
+  }
+  for (; i < 10000; i++) {
+    alloca(100); // GOOD
+  }
+}
+
+void maybeSmallOffset() {
+  int i;
+  if (getInt()) {
+    i = 0;
+  } else {
+    i = 9997;
+  }
+  for (; i < 10000; i++) {
+    alloca(100); // BAD
+  }
+}
+
+void incBefore() {
+  int i = -1;
+  i++; // not understood by data flow
+  for (; i < 2; i++) {
+    alloca(100); // GOOD [FALSE POSITIVE]
+  }
+}
+
+void nestedAddsUp() {
+  for (int i = 0; i < 16; i++) {
+    for (int j = 0; j < 16; j++) {
+      alloca(100); // BAD [NOT DETECTED]
+    }
+  }
+}
+
+void nestedWithReset() {
+  bool stop = 0;
+
+  for (int i = 0; i < 1; i++) {
+    stop = 0;
+    do {
+      stop = 1;
+      alloca(100); // GOOD
+    } while (!stop);
+    stop = 0;
+  }
+}
+
+void eqFalse() {
+  for (int stop = 0; stop == 0; stop = 5) {
+    alloca(100); // GOOD
+  }
+}
+
+void eqFalseFlipped() {
+  for (int stop = 0; stop == 0; stop = 0) {
+    alloca(100); // BAD
+  }
+}
+
+void neFalse() {
+  for (bool go_on = true; go_on != 0; go_on = false) {
+    alloca(100); // GOOD
+  }
+}
+
+void eqTrue() {
+  for (bool go_on = false; go_on == true; go_on = false) {
+    alloca(100); // GOOD
+  }
+}
+
+void countDownFor() {
+  for (int i = 2; i >= 0; i--) {
+    alloca(100); // GOOD
+  }
+}
+
+void countDownWhile() {
+  int i;
+  i = 2;
+  while (--i >= 0) {
+    alloca(100); // GOOD
+  }
+}
+
+void countDownAssignAdd() {
+  for (int i = 2; i >= 0; i = i - 1) {
+    alloca(100); // GOOD
+  }
+}
+
+void countDownWrong() {
+  for (int i = 2-1; i >= 0; i++) {
+    alloca(100); // BAD
+  }
+}
+
+void countUpFromUnsigned(unsigned long i) {
+  while (i < 10) {
+    i = i + 1;
+    alloca(100); // GOOD
+  }
+}