add safe_float functions

* modified versions of safe_float functions suggested by Pascal

* include float.h when --float is passed

* should have mentioned in previous commit: floating point support
is disabled by default, passing --float to enable it

runtime/safe_math.m4

@@ -287,4 +287,77 @@ safe_unsigned_math(uint32_t,UINT32_MAX)
 safe_unsigned_math(uint64_t,UINT64_MAX)
 #endif
 
+dnl safe floating point computation, based on Pascal's suggestion
+
+define(`safe_float_math',`
+
+STATIC $1
+FUNC_NAME(add_func_$1_f_f)($1 sf1, $1 sf2 LOG_INDEX)
+{
+  LOG_EXEC
+  return 
+#ifndef UNSAFE_FLOAT
+    (fabs((0.5 * sf1) + (0.5 * sf2)) > (0.5 * DBL_MAX)) ? 
+    UNDEFINED(sf1) :
+#endif
+    (sf1 + sf2);
+}
+
+STATIC $1
+FUNC_NAME(sub_func_$1_f_f)($1 sf1, $1 sf2 LOG_INDEX)
+{
+  LOG_EXEC
+  return 
+#ifndef UNSAFE_FLOAT
+    (fabs((0.5 * sf1) - (0.5 * sf2)) > (0.5 * DBL_MAX)) ? 
+    UNDEFINED(sf1) :
+#endif
+    (sf1 - sf2);
+}
+
+STATIC $1
+FUNC_NAME(mul_func_$1_f_f)($1 sf1, $1 sf2 LOG_INDEX)
+{
+  LOG_EXEC
+  return 
+#ifndef UNSAFE_FLOAT
+    (fabs((0x1.0p-512 * sf1) * (0x1.0p-512 * sf2)) > (0x1.0p-1024 * DBL_MAX)) ?
+    UNDEFINED(sf1) :
+#endif
+    (sf1 * sf2);
+}
+
+STATIC $1
+FUNC_NAME(div_func_$1_f_f)($1 sf1, $1 sf2 LOG_INDEX)
+{
+  LOG_EXEC
+  return 
+#ifndef UNSAFE_FLOAT
+    (((sf2 == 0.0) || (fabs((0x1.0p-600 * sf1) / (0x1.0p600 * sf2))) > (0x1.0p-1000 * DBL_MAX))) ?
+    UNDEFINED(sf1) :
+#endif
+    (sf1 / sf2);
+}
+
+')
+
+safe_float_math(float)
+
+define(`safe_float_conversion',`
+STATIC $2
+FUNC_NAME(convert_func_$1_to_$2)($1 sf1 LOG_INDEX)
+{
+  LOG_EXEC
+  return 
+#ifndef UNSAFE_FLOAT
+    ((sf1 <= $3) || (sf1 >= $4)) ?
+    UNDEFINED($4) :
+#endif
+    (($2)(sf1));
+}
+')
+
+safe_float_conversion(float, int32_t, INT32_MIN, INT32_MAX)
+
+
 #endif

src/OutputMgr.cpp

@@ -286,6 +286,9 @@ OutputMgr::OutputHeader(int argc, char *argv[], unsigned long seed)
 		out << "#define NO_LONGLONG" << std::endl;
 		out << endl;
 	}
+	if (!CGOptions::enable_float()) {
+		out << "#include <float.h>\n";
+	}
 
 	ExtensionMgr::OutputHeader(out);