[pulseaudio-discuss] [PATCH v4] NetBSD: Stop depending upon nonstandard __WORDSIZE

[Kamil Rytarowski]

There is no way to check CPU type in a portable way across ABIs.

Assume if pointers are 64-bit that CPU is capable to perform fast
64-bit operations. Add an extra check to handle x32-ABI.

PulseAudio by default builds with -Wundef. If we add -Werror=undef this
missing define is fatal. By default build log is full of entries like:

In file included from ./pulsecore/core.h:47:0,
                 from ./pulsecore/module.h:31,
                 from ./pulsecore/sink-input.h:31,
                 from pulsecore/sound-file-stream.c:36:
./pulsecore/sample-util.h: In function 'pa_mult_s16_volume':
./pulsecore/sample-util.h:58:5: warning: "__WORDSIZE" is not defined [-Wundef]
 #if __WORDSIZE == 64 || ((ULONG_MAX) > (UINT_MAX))
     ^

(NetBSD-7.99.21 with default GCC 4.8.5)

This change fixes build issues on NetBSD.

This also address a bug reported by Shawn Walker from Oracle (possibly Solaris):
Bug 90880 - builds can fail due to non-portable glibc-specific internal macro usage
---
 configure.ac                | 11 +++++++++++
 src/pulsecore/sample-util.h |  2 +-
 src/tests/mult-s16-test.c   |  8 +++-----
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/configure.ac b/configure.ac
index b9cd3d1..195b265 100644
--- a/configure.ac
+++ b/configure.ac
@@ -463,6 +463,17 @@ AC_TYPE_OFF_T
 AC_TYPE_UID_T
 AC_CHECK_DECLS(environ)
 
+AC_CHECK_SIZEOF(void*)
+
+fast_64bit_operations="no"
+# This check covers x32-ABI
+AC_CHECK_DECL([__x86_64__], [fast_64bit_operations="yes"], [], [])
+if test "x$fast_64bit_operations" = "xno"; then
+    AS_IF([test $ac_cv_sizeof_voidp -ge 8], [fast_64bit_operations="yes"])
+fi
+
+AS_IF([test "x$fast_64bit_operations" = "xyes"], AC_DEFINE([HAVE_FAST_64BIT_OPERATIONS], 1, [Have CPU with fast 64-bit operations?]))
+
 # SIGXCPU
 AX_CHECK_DEFINE([signal.h], [SIGXCPU], [HAVE_SIGXCPU=1], [HAVE_SIGXCPU=0])
 AS_IF([test "x$HAVE_SIGXCPU" = "x1"], AC_DEFINE([HAVE_SIGXCPU], 1, [Have SIGXCPU?]))
diff --git a/src/pulsecore/sample-util.h b/src/pulsecore/sample-util.h
index c817bc9..3d53ebe 100644
--- a/src/pulsecore/sample-util.h
+++ b/src/pulsecore/sample-util.h
@@ -55,7 +55,7 @@ void pa_deinterleave(const void *src, void *dst[], unsigned channels, size_t ss,
 void pa_sample_clamp(pa_sample_format_t format, void *dst, size_t dstr, const void *src, size_t sstr, unsigned n);
 
 static inline int32_t pa_mult_s16_volume(int16_t v, int32_t cv) {
-#if __WORDSIZE == 64 || ((ULONG_MAX) > (UINT_MAX))
+#if HAVE_FAST_64BIT_OPERATIONS
     /* Multiply with 64 bit integers on 64 bit platforms */
     return (v * (int64_t) cv) >> 16;
 #else
diff --git a/src/tests/mult-s16-test.c b/src/tests/mult-s16-test.c
index d2a351c..845e61c 100644
--- a/src/tests/mult-s16-test.c
+++ b/src/tests/mult-s16-test.c
@@ -93,12 +93,10 @@ int main(int argc, char *argv[]) {
     if (!getenv("MAKE_CHECK"))
         pa_log_set_level(PA_LOG_DEBUG);
 
-#if __WORDSIZE == 64 || ((ULONG_MAX) > (UINT_MAX))
-    pa_log_debug("This seems to be 64-bit code.");
-#elif  __WORDSIZE == 32
-    pa_log_debug("This seems to be 32-bit code.");
+#if HAVE_FAST_64BIT_OPERATIONS
+    pa_log_debug("Detected CPU with fast 64-bit operations.");
 #else
-    pa_log_debug("Don't know if this is 32- or 64-bit code.");
+    pa_log_debug("Not detected CPU with fast 64-bit operations.");
 #endif
 
     s = suite_create("Mult-s16");
-- 
2.6.4