clang/test/Analysis/svalbuilder-casts.cpp

   1 // RUN: %clang_analyze_cc1 %s \
   2 // RUN:   -analyzer-checker=core \
   3 // RUN:   -analyzer-checker=debug.ExprInspection \
   4 // RUN:   -analyzer-config support-symbolic-integer-casts=true \
   5 // RUN:   -analyzer-config eagerly-assume=false \
   6 // RUN:   -triple x86_64-unknown-linux-gnu \
   7 // RUN:   -verify
   8
   9 // Test that the SValBuilder is able to look up and use a constraint for an
  10 // operand of a SymbolCast, when the operand is constrained to a const value.
  11
  12 void clang_analyzer_eval(bool);
  13
  14 extern void abort() __attribute__((__noreturn__));
  15 #define assert(expr) ((expr) ? (void)(0) : abort())
  16
  17 void test(int x) {
  18   // Constrain a SymSymExpr to a constant value.
  19   assert(x * x == 1);
  20   // It is expected to be able to get the constraint for the operand of the
  21   // cast.
  22   clang_analyzer_eval((char)(x * x) == 1); // expected-warning{{TRUE}}
  23   clang_analyzer_eval((long)(x * x) == 1); // expected-warning{{TRUE}}
  24 }
  25
  26 void test1(int x, int y) {
  27   // Even if two lower bytes of `x` equal to zero, it doesn't mean that
  28   // the entire `x` is zero. We are not able to know the exact value of x.
  29   // It can be one of  65536 possible values like
  30   // [0, 65536, -65536, 131072, -131072, ...]. To avoid huge range sets we
  31   // still assume `x` in the range [INT_MIN, INT_MAX].
  32   assert((short)x == 0); // Lower two bytes are set to 0.
  33
  34   static_assert((short)65536 == 0, "");
  35   static_assert((short)-65536 == 0, "");
  36   static_assert((short)131072 == 0, "");
  37   static_assert((short)-131072 == 0, "");
  38   clang_analyzer_eval(x == 0);       // expected-warning{{UNKNOWN}}
  39
  40   // These are not truncated to short as zero.
  41   static_assert((short)1 != 0, "");
  42   clang_analyzer_eval(x == 1);       // expected-warning{{FALSE}}
  43   static_assert((short)-1 != 0, "");
  44   clang_analyzer_eval(x == -1);      // expected-warning{{FALSE}}
  45   static_assert((short)65537 != 0, "");
  46   clang_analyzer_eval(x == 65537);   // expected-warning{{FALSE}}
  47   static_assert((short)-65537 != 0, "");
  48   clang_analyzer_eval(x == -65537);  // expected-warning{{FALSE}}
  49   static_assert((short)131073 != 0, "");
  50   clang_analyzer_eval(x == 131073);  // expected-warning{{FALSE}}
  51   static_assert((short)-131073 != 0, "");
  52   clang_analyzer_eval(x == -131073); // expected-warning{{FALSE}}
  53
  54   // Check for implicit cast.
  55   short s = y;
  56   assert(s == 0);
  57   clang_analyzer_eval(y == 0); // expected-warning{{UNKNOWN}}
  58 }