Error compiling ATTRIBUTE_ALIGNED (workaround suggested)

[Lennart Börjeson]

To whom it may concern,

after my latest hg pull -u, I get the following error compiling ZGC (partial output):

Compiling 300 files for BUILD_jdk.javadoc.interim
In file included from /home/lennartb/zgc/src/hotspot/share/utilities/globalDefinitions.hpp:32:0,
                 from /home/lennartb/zgc/src/hotspot/share/utilities/align.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/runtime/globals.hpp:29,
                 from /home/lennartb/zgc/src/hotspot/share/memory/allocation.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/oops/array.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/memory/universe.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/code/oopRecorder.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/asm/codeBuffer.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/asm/assembler.hpp:28,
                 from /home/lennartb/zgc/src/hotspot/share/precompiled/precompiled.hpp:31:
/home/lennartb/zgc/src/hotspot/share/utilities/globalDefinitions_gcc.hpp:280:63: error: requested alignment is not an integer constant
 #define ATTRIBUTE_ALIGNED(x)        __attribute__((aligned(x)))
                                                               ^
/home/lennartb/zgc/src/hotspot/share/gc/z/zMarkStack.hpp:97:36: note: in expansion of macro ‘ATTRIBUTE_ALIGNED’
   ZMarkStackMagazineList _freelist ATTRIBUTE_ALIGNED(ZCacheLineSize);
                                    ^
/home/lennartb/zgc/src/hotspot/share/utilities/globalDefinitions_gcc.hpp:280:63: error: requested alignment is not an integer constant
 #define ATTRIBUTE_ALIGNED(x)        __attribute__((aligned(x)))
                                                               ^
/home/lennartb/zgc/src/hotspot/share/gc/z/zMarkStack.hpp:98:36: note: in expansion of macro ‘ATTRIBUTE_ALIGNED’
   ZMarkStackSpace        _space    ATTRIBUTE_ALIGNED(ZCacheLineSize);
                                    ^

I believe this is an error in GCC 4.8.5, which is the one my RedHat systems use. Cf. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53017 <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53017>, which I think is relevant despite concerning vector_size and not aligned, since when I patch globalDefinitions_gcc.hpp thus:

$ hg diff
diff -r c585f4a40572 src/hotspot/share/utilities/globalDefinitions_gcc.hpp
--- a/src/hotspot/share/utilities/globalDefinitions_gcc.hpp	Mon Apr 30 11:35:42 2018 +0200
+++ b/src/hotspot/share/utilities/globalDefinitions_gcc.hpp	Fri May 04 13:58:34 2018 +0200
@@ -277,6 +277,6 @@
 #define UNLIKELY(x)                  __builtin_expect(!!(x), 0)
 
 // Alignment
-#define ATTRIBUTE_ALIGNED(x)        __attribute__((aligned(x)))
+#define ATTRIBUTE_ALIGNED(x)        __attribute__((aligned(x+0)))
 
 #endif // SHARE_VM_UTILITIES_GLOBALDEFINITIONS_GCC_HPP


the error disappeared and all is well.


Best regards,

/Lennart