clang/test/Analysis/ptr-arith.cpp

   1 // RUN: %clang_analyze_cc1 -Wno-unused-value -std=c++14 -analyzer-checker=core,debug.ExprInspection,alpha.core.PointerArithm -verify %s
   2 struct X {
   3   int *p;
   4   int zero;
   5   void foo () {
   6     reset(p - 1);
   7   }
   8   void reset(int *in) {
   9     while (in != p) // Loop must be entered.
  10       zero = 1;
  11   }
  12 };
  13
  14 int test (int *in) {
  15   X littleX;
  16   littleX.zero = 0;
  17   littleX.p = in;
  18   littleX.foo();
  19   return 5/littleX.zero; // no-warning
  20 }
  21
  22
  23 class Base {};
  24 class Derived : public Base {};
  25
  26 void checkPolymorphicUse() {
  27   Derived d[10];
  28
  29   Base *p = d;
  30   ++p; // expected-warning{{Pointer arithmetic on a pointer to base class is dangerous}}
  31 }
  32
  33 void checkBitCasts() {
  34   long l;
  35   char *p = (char*)&l;
  36   p = p+2;
  37 }
  38
  39 void checkBasicarithmetic(int i) {
  40   int t[10];
  41   int *p = t;
  42   ++p;
  43   int a = 5;
  44   p = &a;
  45   ++p; // expected-warning{{Pointer arithmetic on non-array variables relies on memory layout, which is dangerous}}
  46   p = p + 2; // expected-warning{{}}
  47   p = 2 + p; // expected-warning{{}}
  48   p += 2; // expected-warning{{}}
  49   a += p[2]; // expected-warning{{}}
  50   p = i*0 + p;
  51   p = p + i*0;
  52   p += i*0;
  53 }
  54
  55 void checkArithOnSymbolic(int*p) {
  56   ++p;
  57   p = p + 2;
  58   p = 2 + p;
  59   p += 2;
  60   (void)p[2];
  61 }
  62
  63 struct S {
  64   int t[10];
  65 };
  66
  67 void arrayInStruct() {
  68   S s;
  69   int * p = s.t;
  70   ++p;
  71   S *sp = new S;
  72   p = sp->t;
  73   ++p;
  74   delete sp;
  75 }
  76
  77 void checkNew() {
  78   int *p = new int;
  79   p[1] = 1; // expected-warning{{}}
  80 }
  81
  82 void InitState(int* state) {
  83     state[1] = 1; // expected-warning{{}}
  84 }
  85
  86 int* getArray(int size) {
  87     if (size == 0)
  88       return new int;
  89     return new int[5];
  90 }
  91
  92 void checkConditionalArray() {
  93     int* maybeArray = getArray(0);
  94     InitState(maybeArray);
  95 }
  96
  97 void checkMultiDimansionalArray() {
  98   int a[5][5];
  99    *(*(a+1)+2) = 2;
 100 }
 101
 102 unsigned ptrSubtractionNoCrash(char *Begin, char *End) {
 103   auto N = End - Begin;
 104   if (Begin)
 105     return 0;
 106   return N;
 107 }
 108
 109 // Bug 34309
 110 bool ptrAsIntegerSubtractionNoCrash(__UINTPTR_TYPE__ x, char *p) {
 111   __UINTPTR_TYPE__ y = (__UINTPTR_TYPE__)p - 1;
 112   return y == x;
 113 }
 114
 115 // Bug 34374
 116 bool integerAsPtrSubtractionNoCrash(char *p, __UINTPTR_TYPE__ m) {
 117   auto n = p - reinterpret_cast<char*>((__UINTPTR_TYPE__)1);
 118   return n == m;
 119 }