Merge branch 'wrapped-math-funcptrs'

Related to GH-17.

RELEASES.txt

@@ -399,6 +399,10 @@ Planned
   constants internally (e.g. use 0x7fffffffL - 1L instead of -0x80000000L);
   this fixed a concrete problem with at least VS2010 + x64
 
+* Portability fix for avoiding direct function pointers to built-in functions
+  (especially math functions) because they may be implemented as inline
+  functions or macros on some platforms or polyfill headers
+
 * Portability fixes for MSVC, avoid secure CRT warnings to work better with
   Windows Store apps
 

src/duk_bi_math.c

@@ -191,8 +191,69 @@ static double duk__pow_fixed(double x, double y) {
 	return DUK_DOUBLE_NAN;
 }
 
+/* Wrappers for calling standard math library methods.  These may be required
+ * on platforms where one or more of the math built-ins are defined as macros
+ * or inline functions and are thus not suitable to be used as function pointers.
+ */
+#if defined(DUK_USE_AVOID_PLATFORM_FUNCPTRS)
+static double duk__fabs(double x) {
+	return fabs(x);
+}
+static double duk__acos(double x) {
+	return acos(x);
+}
+static double duk__asin(double x) {
+	return asin(x);
+}
+static double duk__atan(double x) {
+	return atan(x);
+}
+static double duk__ceil(double x) {
+	return ceil(x);
+}
+static double duk__cos(double x) {
+	return cos(x);
+}
+static double duk__exp(double x) {
+	return exp(x);
+}
+static double duk__floor(double x) {
+	return floor(x);
+}
+static double duk__log(double x) {
+	return log(x);
+}
+static double duk__sin(double x) {
+	return sin(x);
+}
+static double duk__sqrt(double x) {
+	return sqrt(x);
+}
+static double duk__tan(double x) {
+	return tan(x);
+}
+static double duk__atan2(double x, double y) {
+	return atan2(x, y);
+}
+#endif  /* DUK_USE_AVOID_PLATFORM_FUNCPTRS */
+
 /* order must match constants in genbuiltins.py */
 static const duk__one_arg_func duk__one_arg_funcs[] = {
+#if defined(DUK_USE_AVOID_PLATFORM_FUNCPTRS)
+	duk__fabs,
+	duk__acos,
+	duk__asin,
+	duk__atan,
+	duk__ceil,
+	duk__cos,
+	duk__exp,
+	duk__floor,
+	duk__log,
+	duk__round_fixed,
+	duk__sin,
+	duk__sqrt,
+	duk__tan
+#else
 	DUK_FABS,
 	DUK_ACOS,
 	DUK_ASIN,
@@ -206,12 +267,18 @@ static const duk__one_arg_func duk__one_arg_funcs[] = {
 	DUK_SIN,
 	DUK_SQRT,
 	DUK_TAN
+#endif
 };
 
 /* order must match constants in genbuiltins.py */
 static const duk__two_arg_func duk__two_arg_funcs[] = {
+#if defined(DUK_USE_AVOID_PLATFORM_FUNCPTRS)
+	duk__atan2,
+	duk__pow_fixed
+#else
 	DUK_ATAN2,
 	duk__pow_fixed
+#endif
 };
 
 duk_ret_t duk_bi_math_object_onearg_shared(duk_context *ctx) {

src/duk_features.h.in

@@ -1575,6 +1575,19 @@ typedef FILE duk_file;
 #define DUK_MEMZERO(p,n) \
 	DUK_MEMSET((p), 0, (n))
 
+/*
+ *  Avoiding platform function pointers.
+ *
+ *  On some platforms built-in functions may be implemented as macros or
+ *  inline functions, so they can't be necessarily addressed by function
+ *  pointers.  This is certainly the case with some platform "polyfills"
+ *  which provide missing C99/C++11 functions through macros, and may be
+ *  the case with VS2013 (see GH-17).
+ */
+
+/* This is now the default: the cost in footprint is negligible. */
+#define DUK_USE_AVOID_PLATFORM_FUNCPTRS
+
 /*
  *  Vararg macro wrappers.  We need va_copy() which is defined in C99 / C++11,
  *  so an awkward replacement is needed for pre-C99 / pre-C++11 environments.