Check __builtin___clear_cache() at configuration time

Fixup commit 39b83981 ("Flush icache with __builtin___clear_cache() in
tests when compiling with GCC") to fix compilation with older GCC
versions that do not provide __builtin___clear_cache().

configure.in

@@ -277,6 +277,17 @@ if test x$intel_compiler = xyes; then
   AC_MSG_RESULT([$have_static_libcxa])
 fi
 
+AC_MSG_CHECKING([for __builtin___clear_cache])
+AC_LINK_IFELSE(
+  [AC_LANG_PROGRAM([[]], [[__builtin___clear_cache(0, 0)]])],
+  [have__builtin___clear_cache=yes],
+  [have__builtin___clear_cache=no])
+if test x$have__builtin___clear_cache = xyes; then
+  AC_DEFINE([HAVE__BUILTIN___CLEAR_CACHE], [1],
+            [Defined if __builtin___clear_cache() is available])
+fi
+AC_MSG_RESULT([$have__builtin___clear_cache])
+
 CCASFLAGS="${CCASFLAGS} ${CPPFLAGS}"
 
 arch="$target_arch"

tests/Gtest-dyn1.c

@@ -25,6 +25,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 
 /* This file tests dynamic code-generation via function-cloning.  */
 
+#include "flush-cache.h"
+
 #include <libunwind.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -86,10 +88,6 @@ struct fdesc
 # define get_gp(fdesc)		(0)
 #endif
 
-#ifndef __GNUC__
-extern void flush_cache (void *addr, size_t len);
-#endif
-
 void
 template (int i, template_t self,
 	  int (*printer)(const char *, ...), const char *fmt, const char **arr)
@@ -187,11 +185,7 @@ main (int argc, char *argv[] __attribute__((unused)))
   mprotect ((void *) ((long) mem & ~(getpagesize () - 1)),
 	    2*getpagesize(), PROT_READ | PROT_WRITE | PROT_EXEC);
 
-#ifdef __GNUC__
-  __builtin___clear_cache(mem, mem + MAX_FUNC_SIZE);
-#else
   flush_cache (mem, MAX_FUNC_SIZE);
-#endif
 
   signal (SIGSEGV, sighandler);
 

tests/Makefile.am

@@ -101,15 +101,16 @@ Lia64_test_rbs_SOURCES = Lia64-test-rbs.c ia64-test-rbs-asm.S ia64-test-rbs.h
 Gia64_test_rbs_SOURCES = Gia64-test-rbs.c ia64-test-rbs-asm.S ia64-test-rbs.h
 Lia64_test_nat_SOURCES = Lia64-test-nat.c ia64-test-nat-asm.S
 Gia64_test_nat_SOURCES = Gia64-test-nat.c ia64-test-nat-asm.S
-ia64_test_dyn1_SOURCES = ia64-test-dyn1.c ia64-dyn-asm.S flush-cache.S
+ia64_test_dyn1_SOURCES = ia64-test-dyn1.c ia64-dyn-asm.S flush-cache.S \
+				flush-cache.h
 ppc64_test_altivec_SOURCES = ppc64-test-altivec.c  ppc64-test-altivec-utils.c
 ppc64_test_wchar_SOURCES = ppc64-test-wchar.c
 Gtest_init_SOURCES = Gtest-init.cxx
 Ltest_init_SOURCES = Ltest-init.cxx
 Ltest_cxx_exceptions_SOURCES = Ltest-cxx-exceptions.cxx
 
-Gtest_dyn1_SOURCES = Gtest-dyn1.c flush-cache.S
+Gtest_dyn1_SOURCES = Gtest-dyn1.c flush-cache.S flush-cache.h
-Ltest_dyn1_SOURCES = Ltest-dyn1.c flush-cache.S
+Ltest_dyn1_SOURCES = Ltest-dyn1.c flush-cache.S flush-cache.h
 test_static_link_SOURCES = test-static-link-loc.c test-static-link-gen.c
 test_static_link_LDFLAGS = -static
 forker_LDFLAGS = -static

tests/flush-cache.S

@@ -1,4 +1,8 @@
-#ifndef __GNUC__
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifndef HAVE__BUILTIN___CLEAR_CACHE
 
 #if defined(__ia64__)
 

tests/flush-cache.h

@@ -0,0 +1,38 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#ifndef FLUSH_CACHE_H
+#define FLUSH_CACHE_H
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifdef HAVE__BUILTIN___CLEAR_CACHE
+#define flush_cache(ADDR, LEN) \
+  __builtin___clear_cache((ADDR), (ADDR) + (LEN))
+#else
+#include <stddef.h>
+extern void flush_cache (void *addr, size_t len);
+#endif
+
+#endif /* FLUSH_CACHE_H */

tests/ia64-test-dyn1.c

@@ -1,3 +1,5 @@
+#include "flush-cache.h"
+
 #include <assert.h>
 #include <libunwind.h>
 #include <unistd.h>
@@ -20,10 +22,6 @@ int verbose;
 # define EXTRA			0
 #endif
 
-#ifndef __GNUC__
-extern void flush_cache (void *addr, size_t len);
-#endif
-
 int
 make_executable (void *addr, size_t len)
 {
@@ -33,11 +31,7 @@ make_executable (void *addr, size_t len)
       perror ("mprotect");
       return -1;
     }
-#ifdef __GNUC__
-  __builtin___clear_cache(addr, addr + len);
-#else
   flush_cache (addr, len);
-#endif
   return 0;
 }