clang/test/Analysis/builtin_bitcast.cpp

   1 // RUN: %clang_analyze_cc1 -triple x86_64-unknown-unknown -verify %s \
   2 // RUN:   -analyzer-checker=core,debug.ExprInspection
   3
   4 template <typename T> void clang_analyzer_dump(T);
   5 using size_t = decltype(sizeof(int));
   6
   7 __attribute__((always_inline)) static inline constexpr unsigned int _castf32_u32(float __A) {
   8   return __builtin_bit_cast(unsigned int, __A); // no-warning
   9 }
  10
  11 void test(int i) {
  12   _castf32_u32(42);
  13
  14   float f = 42;
  15
  16   // Loading from a floating point value results in unknown,
  17   // which later materializes as a conjured value.
  18   auto g = __builtin_bit_cast(unsigned int, f);
  19   clang_analyzer_dump(g);
  20   // expected-warning-re@-1 {{{{^conj_\$[0-9]+{unsigned int,}}}}
  21
  22   auto g2 = __builtin_bit_cast(unsigned int, 42.0f);
  23   clang_analyzer_dump(g2);
  24   // expected-warning-re@-1 {{{{^conj_\$[0-9]+{unsigned int,}}}}
  25
  26   auto g3 = __builtin_bit_cast(unsigned int, i);
  27   clang_analyzer_dump(g3);
  28   // expected-warning-re@-1 {{{{^reg_\$[0-9]+<int i>}}}}
  29
  30   auto g4 = __builtin_bit_cast(unsigned long, &i);
  31   clang_analyzer_dump(g4);
  32   // expected-warning@-1 {{&i [as 64 bit integer]}}
  33 }
  34
  35 struct A {
  36   int n;
  37   void set(int x) {
  38     n = x;
  39   }
  40 };
  41 void gh_69922(size_t p) {
  42   // expected-warning-re@+1 {{(reg_${{[0-9]+}}<size_t p>) & 1U}}
  43   clang_analyzer_dump(__builtin_bit_cast(A*, p & 1));
  44
  45   __builtin_bit_cast(A*, p & 1)->set(2); // no-crash
  46   // However, since the `this` pointer is expected to be a Loc, but we have
  47   // NonLoc there, we simply give up and resolve it as `Unknown`.
  48   // Then, inside the `set()` member function call we can't evaluate the
  49   // store to the member variable `n`.
  50
  51   clang_analyzer_dump(__builtin_bit_cast(A*, p & 1)->n); // Ideally, this should print "2".
  52   // expected-warning-re@-1 {{(reg_${{[0-9]+}}<size_t p>) & 1U}}
  53 }