Current API19 (and 23) libc++ bug feature detection

patch-to-features.py

  # Android added %a printf starting with Android L (API 21).
  Feature(name='android-no-printf-a',
          when=lambda cfg: _isAndroid(cfg) and not _isAndroidApiAtLeast(cfg, 21) and
                           not programSucceeds(cfg, """
            #include <stdio.h>
            #include <string.h>
            int main(int, char**) {
              char buf[100];
              snprintf(buf, sizeof(buf), "%a", 0.0);
              return strcmp(buf, "0x0p+0");
            }
          """)),

  # Android added hex-float strto{f,d,ld} starting with Android L (API 21).
  Feature(name='android-no-strtof-hex-flt',
          when=lambda cfg: _isAndroid(cfg) and not _isAndroidApiAtLeast(cfg, 21) and
                           not programSucceeds(cfg, """
            #include <stdlib.h>
            int main(int, char**) {
              return !(strtof("0x1p+4", NULL) == 16 &&
                       strtod("0x1p+4", NULL) == 16 &&
                       strtold("0x1p+4", NULL) == 16);
            }
          """),
          actions=[AddCompileFlag('-D_LIBCPP_TESTING_ANDROID_NO_STRTOF_HEX_FLT')]),

  # Android added %F printf starting with Android L (API 21).
  Feature(name='android-no-printf-F',
          when=lambda cfg: _isAndroid(cfg) and not _isAndroidApiAtLeast(cfg, 21) and
                           not programSucceeds(cfg, """
            #include <stdio.h>
            #include <string.h>
            int main(int, char**) {
              char buf[100];
              snprintf(buf, sizeof(buf), "%1.1F", 0.0);
              return strcmp(buf, "0.0");
            }
          """),
          actions=[AddCompileFlag('-D_LIBCPP_TESTING_ANDROID_NO_PRINTF_CAPITAL_F')]),

  # Android %f prints negative 0 like positive 0 prior to Android L (API 21).
  Feature(name='android-broken-printf-neg0',
          when=lambda cfg: _isAndroid(cfg) and not _isAndroidApiAtLeast(cfg, 21) and
                           not programSucceeds(cfg, """
            #include <stdio.h>
            #include <string.h>
            int main(int, char**) {
              char buf[100];
              snprintf(buf, sizeof(buf), "%1.1f", -0.0);
              return strcmp(buf, "-0.0");
            }
          """),
          actions=[AddCompileFlag('-D_LIBCPP_TESTING_ANDROID_BROKEN_NEG0')]),

  # Prior to Android L (API 21), INFINITY and NAN are formatted as "Inf" and
  # "NaN". Android L and up use inf/INF and nan/NAN depending on format letter
  # case.
  Feature(name='android-printf-nan-inf-mixed-case',
          when=lambda cfg: _isAndroid(cfg) and not _isAndroidApiAtLeast(cfg, 21) and
                           not programSucceeds(cfg, """
            #include <math.h>
            #include <stdio.h>
            #include <string.h>
            int main(int, char**) {
              char buf[100];
              snprintf(buf, sizeof(buf), "%f %f", INFINITY, NAN);
              return strcmp(buf, "inf nan");
            }
          """),
          actions=[AddCompileFlag('-D_LIBCPP_TESTING_ANDROID_PRINTF_NAN_INF_MIXED_CASE')]),

  # Considering NAN and -NAN:
  #  - Android K (API 19): "%f" prints "NaN", "%+f" prints "+NaN" (even for
  #    -NAN, the sign bit is ignored).
  #  - Android L (API 21): "%f" and "%+f" print "nan".
  #  - Android M (API 23) and up: "%f" prints "nan" or "-nan", "%+f" prints
  #    "+nan" or "-nan".
  # Set this feature for L, where the sign is never printed. Otherwise, "%+f"
  # for non-negative NAN prints the '+' sign.
  Feature(name='android-printf-nan-no-sign',
          when=lambda cfg: _isAndroid(cfg) and not _isAndroidApiAtLeast(cfg, 23) and
                           not programSucceeds(cfg, """
            #include <math.h>
            #include <stdio.h>
            int main(int, char**) {
              char buf[100];
              snprintf(buf, sizeof(buf), "%+f", NAN);
              return buf[0] != '+';
            }
          """),
          actions=[AddCompileFlag('-D_LIBCPP_TESTING_ANDROID_PRINTF_NAN_NO_SIGN')]),