[analyzer] Fix test for PR12206, which was failing on i386.

llvm-svn: 156941

1 files changed, 96 insertions, 0 deletions

diff --git a/clang/test/Analysis/comparison-implicit-casts.cpp b/clang/test/Analysis/comparison-implicit-casts.cpp
new file mode 100644
index 00000000000..04079c23090
--- /dev/null
+++ b/clang/test/Analysis/comparison-implicit-casts.cpp
@@ -0,0 +1,96 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix.cstring,debug.ExprInspection -analyzer-constraints=basic -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix.cstring,debug.ExprInspection -analyzer-constraints=range -verify %s
+
+// This file runs in C++ mode so that the comparison type is 'bool', not 'int'.
+void clang_analyzer_eval(int);
+typedef typeof(sizeof(int)) size_t;
+
+// PR12206/12510 - When SimpleSValBuilder figures out that a symbol is fully
+// constrained, it should cast the value to the result type in a binary
+// operation...unless the binary operation is a comparison, in which case the
+// two arguments should be the same type, but won't match the result type.
+//
+// This is not directly related to additive folding, but we use SValBuilder's
+// additive folding to tickle the bug. ExprEngine will simplify fully-constrained
+// symbols, so SValBuilder will only see them if they are (a) part of an evaluated
+// SymExpr (e.g. with additive folding) or (b) generated by a checker (e.g.
+// unix.cstring's strlen() modelling).
+void PR12206(int x) {
+  size_t comparisonSize = sizeof(1 == 1);
+
+  // Sanity check. This test is useless if size_t isn't bigger than bool.
+  clang_analyzer_eval(sizeof(size_t) > comparisonSize); // expected-warning{{TRUE}}
+
+  // Build a SymIntExpr, dependent on x.
+  int local = x - 1;
+
+  // Create a value that requires more bits to store than a comparison result.
+  int value = 1;
+  value <<= 8 * comparisonSize;
+  value += 1;
+
+  // Constrain the value of x.
+  if (x != value) return;
+
+  // Constant-folding will turn (local+1) back into the symbol for x.
+  // The point of this dance is to make SValBuilder be responsible for
+  // turning the symbol into a ConcreteInt, rather than ExprEngine.
+
+  // Test relational operators.
+  clang_analyzer_eval((local + 1) >= 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(2 <= (local + 1)); // expected-warning{{TRUE}}
+
+  // Test equality operators.
+  clang_analyzer_eval((local + 1) != 1); // expected-warning{{TRUE}}
+  clang_analyzer_eval(1 != (local + 1)); // expected-warning{{TRUE}}
+}
+
+void PR12206_truncation(signed char x) {
+  // Build a SymIntExpr, dependent on x.
+  signed char local = x - 1;
+
+  // Constrain the value of x.
+  if (x != 1) return;
+
+  // Constant-folding will turn (local+1) back into the symbol for x.
+  // The point of this dance is to make SValBuilder be responsible for
+  // turning the symbol into a ConcreteInt, rather than ExprEngine.
+
+  // Construct a value that cannot be represented by 'char',
+  // but that has the same lower bits as x.
+  signed int value = 1 + (1 << 8);
+
+  // Test relational operators.
+  clang_analyzer_eval((local + 1) < value); // expected-warning{{TRUE}}
+  clang_analyzer_eval(value > (local + 1)); // expected-warning{{TRUE}}
+
+  // Test equality operators.
+  clang_analyzer_eval((local + 1) != value); // expected-warning{{TRUE}}
+  clang_analyzer_eval(value != (local + 1)); // expected-warning{{TRUE}}
+}
+
+// This test is insurance in case we significantly change how SymExprs are
+// evaluated.
+size_t strlen(const char *s);
+void PR12206_strlen(const char *x) {
+  size_t comparisonSize = sizeof(1 == 1);
+
+  // Sanity check. This test is useless if size_t isn't bigger than bool.
+  clang_analyzer_eval(sizeof(size_t) > comparisonSize); // expected-warning{{TRUE}}
+
+  // Create a value that requires more bits to store than a comparison result.
+  size_t value = 1UL;
+  value <<= 8 * comparisonSize;
+  value += 1;
+
+  // Constrain the length of x.
+  if (strlen(x) != value) return;
+
+  // Test relational operators.
+  clang_analyzer_eval(strlen(x) >= 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(2 <= strlen(x)); // expected-warning{{TRUE}}
+
+  // Test equality operators.
+  clang_analyzer_eval(strlen(x) != 1); // expected-warning{{TRUE}}
+  clang_analyzer_eval(1 != strlen(x)); // expected-warning{{TRUE}}
+}