clang/test/Analysis/comparison-implicit-casts.cpp

   1 // RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.cstring,debug.ExprInspection -triple i386-apple-darwin9 -verify %s
   2 // RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.cstring,debug.ExprInspection -triple x86_64-apple-darwin9 -verify %s
   3
   4 // This file runs in C++ mode so that the comparison type is 'bool', not 'int'.
   5 void clang_analyzer_eval(int);
   6 typedef typeof(sizeof(int)) size_t;
   7
   8 // PR12206/12510 - When SimpleSValBuilder figures out that a symbol is fully
   9 // constrained, it should cast the value to the result type in a binary
  10 // operation...unless the binary operation is a comparison, in which case the
  11 // two arguments should be the same type, but won't match the result type.
  12 //
  13 // This is not directly related to additive folding, but we use SValBuilder's
  14 // additive folding to tickle the bug. ExprEngine will simplify fully-constrained
  15 // symbols, so SValBuilder will only see them if they are (a) part of an evaluated
  16 // SymExpr (e.g. with additive folding) or (b) generated by a checker (e.g.
  17 // unix.cstring's strlen() modelling).
  18 void PR12206(int x) {
  19   size_t comparisonSize = sizeof(1 == 1);
  20
  21   // This test is useless if size_t isn't bigger than bool.
  22   clang_analyzer_eval(sizeof(size_t) > comparisonSize); // expected-warning{{TRUE}}
  23
  24   // Build a SymIntExpr, dependent on x.
  25   int local = x - 1;
  26
  27   // Create a value that requires more bits to store than a comparison result.
  28   int value = 1;
  29   value <<= 8 * comparisonSize;
  30   value += 1;
  31
  32   // Constrain the value of x.
  33   if (x != value) return;
  34
  35   // Constant-folding will turn (local+1) back into the symbol for x.
  36   // The point of this dance is to make SValBuilder be responsible for
  37   // turning the symbol into a ConcreteInt, rather than ExprEngine.
  38
  39   // Test relational operators.
  40   clang_analyzer_eval((local + 1) >= 2); // expected-warning{{TRUE}}
  41   clang_analyzer_eval(2 <= (local + 1)); // expected-warning{{TRUE}}
  42
  43   // Test equality operators.
  44   clang_analyzer_eval((local + 1) != 1); // expected-warning{{TRUE}}
  45   clang_analyzer_eval(1 != (local + 1)); // expected-warning{{TRUE}}
  46 }
  47
  48 void PR12206_truncation(signed char x) {
  49   // Build a SymIntExpr, dependent on x.
  50   signed char local = x - 1;
  51
  52   // Constrain the value of x.
  53   if (x != 1) return;
  54
  55   // Constant-folding will turn (local+1) back into the symbol for x.
  56   // The point of this dance is to make SValBuilder be responsible for
  57   // turning the symbol into a ConcreteInt, rather than ExprEngine.
  58
  59   // Construct a value that cannot be represented by 'char',
  60   // but that has the same lower bits as x.
  61   signed int value = 1 + (1 << 8);
  62
  63   // Test relational operators.
  64   clang_analyzer_eval((local + 1) < value); // expected-warning{{TRUE}}
  65   clang_analyzer_eval(value > (local + 1)); // expected-warning{{TRUE}}
  66
  67   // Test equality operators.
  68   clang_analyzer_eval((local + 1) != value); // expected-warning{{TRUE}}
  69   clang_analyzer_eval(value != (local + 1)); // expected-warning{{TRUE}}
  70 }
  71
  72 // This test is insurance in case we significantly change how SymExprs are
  73 // evaluated.
  74 size_t strlen(const char *s);
  75 void PR12206_strlen(const char *x) {
  76   size_t comparisonSize = sizeof(1 == 1);
  77
  78   // This test is useless if size_t isn't bigger than bool.
  79   clang_analyzer_eval(sizeof(size_t) > comparisonSize); // expected-warning{{TRUE}}
  80
  81   // Create a value that requires more bits to store than a comparison result.
  82   size_t value = 1UL;
  83   value <<= 8 * comparisonSize;
  84   value += 1;
  85
  86   // Constrain the length of x.
  87   if (strlen(x) != value) return;
  88
  89   // Test relational operators.
  90   clang_analyzer_eval(strlen(x) >= 2); // expected-warning{{TRUE}}
  91   clang_analyzer_eval(2 <= strlen(x)); // expected-warning{{TRUE}}
  92
  93   // Test equality operators.
  94   clang_analyzer_eval(strlen(x) != 1); // expected-warning{{TRUE}}
  95   clang_analyzer_eval(1 != strlen(x)); // expected-warning{{TRUE}}
  96 }