apr_atomic: Use __atomic builtins when available.

Unlike Intel's atomic builtins (__sync_*), the more recent __atomic builtins
provide atomic load and store for weakly ordered architectures like ARM32 or
powerpc[64], so use them when available (gcc 4.6.3+).



git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1894618 13f79535-47bb-0310-9956-ffa450edef68

5 files changed, 63 insertions, 0 deletions

diff --git a/include/apr.h.in b/include/apr.h.in
index c498376d9..efb791a22 100644
--- a/include/apr.h.in
+++ b/include/apr.h.in
@@ -45,6 +45,26 @@
  * are platform specific and should NOT be relied upon!</em></strong>
  */
 
+/* So that we can test for clang features */
+#ifndef	__has_feature
+#define	__has_feature(x) 0
+#endif
+#ifndef	__has_extension
+#define	__has_extension  __has_feature
+#endif
+#ifndef	__has_include
+#define	__has_include(x) 0
+#endif
+#ifndef	__has_builtin
+#define	__has_builtin(x) 0
+#endif
+
+#if !(defined(__attribute__) \
+      || (defined(__GNUC__) && (__GNUC__ > 2 || (__GNUC__ == 2 && \
+                                                 __GNUC_MINOR__ >= 4))))
+#define __attribute__(x)
+#endif
+
 /* So that we can use inline on some critical functions, and use
  * GNUC attributes (such as to get -Wall warnings for printf-like
  * functions).  Only do this in gcc 2.7 or later ... it may work
@@ -70,6 +90,7 @@
 #endif
 
 #define APR_HAVE_ARPA_INET_H     @arpa_ineth@
+#define APR_HAVE_ASSERT_H        @asserth@
 #define APR_HAVE_CONIO_H         @conioh@
 #define APR_HAVE_CRYPT_H         @crypth@
 #define APR_HAVE_CTYPE_H         @ctypeh@
diff --git a/include/apr.hnw b/include/apr.hnw
index 6db0c9b5e..10ebb390a 100644
--- a/include/apr.hnw
+++ b/include/apr.hnw
@@ -80,6 +80,7 @@ extern "C" {
 #endif
 #define ENUM_BITFIELD(e,n,w)  signed int n : w
 
+#define APR_HAVE_ASSERT_H               1
 #define APR_HAVE_CONIO_H                0
 #define APR_HAVE_CRYPT_H                0
 #define APR_HAVE_CTYPE_H                1
diff --git a/include/apr.hw b/include/apr.hw
index 7cdfd1570..b0c2fe524 100644
--- a/include/apr.hw
+++ b/include/apr.hw
@@ -130,6 +130,7 @@
 #endif
 
 #define APR_HAVE_ARPA_INET_H    0
+#define APR_HAVE_ASSERT_H       1
 #define APR_HAVE_CONIO_H         APR_NOT_IN_WCE
 #define APR_HAVE_CRYPT_H        0
 #define APR_HAVE_CTYPE_H         APR_NOT_IN_WCE
diff --git a/include/apr.hwc b/include/apr.hwc
index 03bcd5e8e..8362fffcb 100644
--- a/include/apr.hwc
+++ b/include/apr.hwc
@@ -129,6 +129,7 @@
 #define APR_NOT_IN_WCE          1
 #endif
 
+#define APR_HAVE_ASSERT_H       1
 #define APR_HAVE_ARPA_INET_H    0
 #define APR_HAVE_CONIO_H         APR_NOT_IN_WCE
 #define APR_HAVE_CRYPT_H        0
diff --git a/include/apr_general.h b/include/apr_general.h
index 4f2a6e8c4..5e53bb63d 100644
--- a/include/apr_general.h
+++ b/include/apr_general.h
@@ -29,6 +29,9 @@
 #include "apr_pools.h"
 #include "apr_errno.h"
 
+#if APR_HAVE_ASSERT_H
+#include <assert.h>
+#endif
 #if APR_HAVE_SIGNAL_H
 #include <signal.h>
 #endif
@@ -112,6 +115,42 @@ typedef enum { APR_WAIT_READ, APR_WAIT_WRITE } apr_wait_type_t;
 #define APR_OFFSETOF(s_type,field) APR_OFFSET(s_type*,field)
 #endif
 
+/**
+ * Compile time assertions.
+ * @param predicate static condition
+ * @param errstring static error message (literal)
+ */
+#if defined(static_assert) \
+    || __has_builtin(static_assert) \
+    || (defined(__cplusplus) && (__cplusplus >= 201103L || \
+                                 __has_extension(cxx_static_assert))) \
+    || (defined(_MSC_VER ) && _MSC_VER >= 1600)
+#define APR_STATIC_ASSERT static_assert
+
+#elif defined(_Static_assert) \
+    || __has_builtin(_Static_assert) \
+    || __has_extension(c_static_assert) \
+    || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && \
+                                               __GNUC_MINOR__ >= 6)))
+#define APR_STATIC_ASSERT _Static_assert
+
+#else  /* !static_assert && !_Static_assert */
+#define APR__STATIC_CONCAT_(x, y) x##y
+#define APR__STATIC_CONCAT(x, y) APR__STATIC_CONCAT_(x, y)
+#if defined(__COUNTER__)
+#define APR_STATIC_ASSERT(predicate, errstring) \
+    typedef struct { \
+        int static_assert_failure:!!(predicate)*2-1; \
+    } APR__STATIC_CONCAT(static_assert_test_, __COUNTER__);
+#else  /* !__COUNTER__ */
+#define APR_STATIC_ASSERT(predicate, errstring) \
+    typedef struct { \
+        int static_assert_failure:!!(predicate)*2-1; \
+    } APR__STATIC_CONCAT(static_assert_test_, __LINE__);
+#endif /* !__COUNTER__ */
+
+#endif /* !static_assert && !_Static_assert */
+
 #ifndef DOXYGEN
 
 /* A couple of prototypes for functions in case some platform doesn't