32/64 bit type issues on Windows
Chris Dennis
cdennis at terracottatech.com
Tue May 22 14:28:58 PDT 2012
Hi All,
I believe that when the Mac OS X support was merged in to the jdk7u-dev forest that a mistake was made regarding Visual Studio's lack of inttypes.h. The symptom of this bug can be seen in the following output:
$ java -showversion -d64 -XX:MaxDirectMemorySize=4g OffHeapAllocationTest
java version "1.7.0_04"
Java(TM) SE Runtime Environment (build 1.7.0_04-b20)
Java HotSpot(TM) 64-Bit Server VM (build 23.0-b21, mixed mode)
Command Line: [-XX:MaxDirectMemorySize=4g]
sun.misc.VM.maxDirectMemory() = 0
java.nio.Bits.maxMemory = 0
Experimenting with different MaxDirectMemorySize values clearly shows this to be a 32-bit wrap-around issue. When Mac OS X support was merged in, the INTX_FORMAT which is used to write the MaxDirectMemorySize global in to the system properties was modified to use PRIdPTR from inttypes.h. As Visual Studio lacks inttypes.h, definitions for this (and the other associated format specifiers) were added to globalDefinitions_visCPP.hpp. However the definitions added are only correct for a 32-bit system. I believe the following changeset corrects that error (no Windows access prevents me from verifying this fix however).
If you need me to file a formal bug report for this then let me know.
Regards,
Chris Dennis
================================================================================
diff -r bca9e76ea254 src/share/vm/utilities/globalDefinitions_visCPP.hpp
--- a/src/share/vm/utilities/globalDefinitions_visCPP.hpp Tue Mar 20 10:17:41 2012 -0700
+++ b/src/share/vm/utilities/globalDefinitions_visCPP.hpp Tue May 22 17:24:57 2012 -0400
@@ -220,9 +220,15 @@
#define PRIu64 "I64u"
#define PRIx64 "I64x"
+#ifdef _LP64
+#define PRIdPTR "I64d"
+#define PRIuPTR "I64u"
+#define PRIxPTR "I64x"
+#else
#define PRIdPTR "d"
#define PRIuPTR "u"
#define PRIxPTR "x"
+#endif
#define offset_of(klass,field) offsetof(klass,field)
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