Merge pull request #65 from floitschG/avoid_undef_cast
Avoid undefined cast to make ASAN happy.
diff --git a/double-conversion/strtod.cc b/double-conversion/strtod.cc
index 4392ae6..e8cc13f 100644
--- a/double-conversion/strtod.cc
+++ b/double-conversion/strtod.cc
@@ -472,6 +472,30 @@
}
}
+static float SanitizedDoubletof(double d) {
+ ASSERT(d >= 0.0);
+ // ASAN has a sanitize check that disallows casting doubles to floats if
+ // they are too big.
+ // https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html#available-checks
+ // The behavior should be covered by IEEE 754, but some projects use this
+ // flag, so work around it.
+ float max_finite = 3.4028234663852885981170418348451692544e+38;
+ // The half-way point between the max-finite and infinity value.
+ // Since infinity has an even significand everything equal or greater than
+ // this value should become infinity.
+ double half_max_finite_infinity =
+ 3.40282356779733661637539395458142568448e+38;
+ if (d >= max_finite) {
+ if (d >= half_max_finite_infinity) {
+ return Single::Infinity();
+ } else {
+ return max_finite;
+ }
+ } else {
+ return static_cast<float>(d);
+ }
+}
+
float Strtof(Vector<const char> buffer, int exponent) {
char copy_buffer[kMaxSignificantDecimalDigits];
Vector<const char> trimmed;
@@ -483,7 +507,7 @@
double double_guess;
bool is_correct = ComputeGuess(trimmed, exponent, &double_guess);
- float float_guess = static_cast<float>(double_guess);
+ float float_guess = SanitizedDoubletof(double_guess);
if (float_guess == double_guess) {
// This shortcut triggers for integer values.
return float_guess;
@@ -506,15 +530,15 @@
double double_next = Double(double_guess).NextDouble();
double double_previous = Double(double_guess).PreviousDouble();
- float f1 = static_cast<float>(double_previous);
+ float f1 = SanitizedDoubletof(double_previous);
float f2 = float_guess;
- float f3 = static_cast<float>(double_next);
+ float f3 = SanitizedDoubletof(double_next);
float f4;
if (is_correct) {
f4 = f3;
} else {
double double_next2 = Double(double_next).NextDouble();
- f4 = static_cast<float>(double_next2);
+ f4 = SanitizedDoubletof(double_next2);
}
(void) f2; // Mark variable as used.
ASSERT(f1 <= f2 && f2 <= f3 && f3 <= f4);
@@ -529,7 +553,7 @@
(f1 == f2 && f2 != f3 && f3 == f4) ||
(f1 == f2 && f2 == f3 && f3 != f4));
- // guess and next are the two possible canditates (in the same way that
+ // guess and next are the two possible candidates (in the same way that
// double_guess was the lower candidate for a double-precision guess).
float guess = f1;
float next = f4;
