AC_USE_SYSTEM_EXTENSIONS
AC_SYS_LARGEFILE
+# Check if the selected C compiler supports atomic builtins
+AE_CC_ATOMIC_BUILTINS
+
+
## ##
## C++ compiler checks ##
## ##
AE_FEATURE_DEFAULT_DISABLE
AE_FEATURE([cds-lfht-iter-debug], [Enable extra debugging checks for lock-free hash table iterator traversal. Alters the rculfhash ABI. Make sure to compile both library and application with matching configuration.])
+# Use compiler atomic builtins, when disabled use our legacy uatomic implementation.
+# Disabled by default
+AE_FEATURE_DEFAULT_DISABLE
+AE_FEATURE([compiler-atomic-builtins], [Enable the use of compiler atomic builtins.])
+
+# emit legacy memory barriers
+# Enable by default
+AE_FEATURE_DEFAULT_ENABLE
+AE_FEATURE([legacy-mb], [Disable legacy memory barriers.])
+
# When given, add -Werror to WARN_CFLAGS and WARN_CXXFLAGS.
# Disabled by default
AE_FEATURE_DEFAULT_DISABLE
AC_DEFINE([CONFIG_CDS_LFHT_ITER_DEBUG], [1], [Enable extra debugging checks for lock-free hash table iterator traversal. Alters the rculfhash ABI. Make sure to compile both library and application with matching configuration.])
])
+AE_IF_FEATURE_ENABLED([compiler-atomic-builtins], [
+ AC_DEFINE([CONFIG_RCU_USE_ATOMIC_BUILTINS], [1], [Use compiler atomic builtins.])
+])
+
+AE_IF_FEATURE_ENABLED([legacy-mb], [
+ AC_DEFINE([CONFIG_RCU_EMIT_LEGACY_MB], [1], [Emit legacy memory barriers that were documented in the APIs.])
+])
## ##
## Set automake variables for optional feature conditionnals in Makefile.am ##
AM_CONDITIONAL([ENABLE_EXAMPLES], AE_IS_FEATURE_ENABLED([shared]))
+## ##
+## Check for optional features dependencies ##
+## ##
+
+
+AE_IF_FEATURE_ENABLED([compiler-atomic-builtins], [
+ AS_IF([test "x$ae_cv_cc_atomic_builtins" != xyes], [
+ AC_MSG_ERROR([The compiler does not support atomic builtins.])
+ ])
+])
+
## ##
## Substitute variables for use in Makefile.am ##
## ##
AE_PPRINT_PROP_BOOL([Multi-flavor support], 1)
+# atomic builtins enabled/disabled
+AE_IS_FEATURE_ENABLED([compiler-atomic-builtins]) && value=1 || value=0
+AE_PPRINT_PROP_BOOL([Use compiler atomic builtins], $value)
+
+# legacy memory barriers
+AE_IS_FEATURE_ENABLED([legacy-mb]) && value=1 || value=0
+AE_PPRINT_PROP_BOOL([Emit legacy memory barriers], $value)
+
report_bindir="`eval eval echo $bindir`"
report_libdir="`eval eval echo $libdir`"