Name: jl125535 Date: 11/17/2003


FULL PRODUCT VERSION :


FULL OS VERSION :
Linux server 2.4.22-lfs-1 #1 SMP Fri Oct 24 12:47:16 PDT 2003 i686 GenuineIntel unknown GNU/Linux


A DESCRIPTION OF THE PROBLEM :
Unable to compile j2sdk 1.4.2 as a source build.

  Bug Report that was sent to GCC.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12590


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Follow Instructions as posted at.

http://java.sun.com/j2se/1.4.2/scsl/build.html


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A complete user-build java sdk, using GCC 3.3.x
ACTUAL -
/usr/src/java/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp: In
   function `jboolean JVM_CX8Field(JNIEnv*, _jobject*, _jfieldID*, long long
   int, long long int)':
/usr/src/java/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp:50:
 error: impossible constraint in `asm'

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
  Fix suggested by GCC.

The problem is with the "o" constriant, if I change it to m (which looks better and is right constraint to use in this case because the memory location could be any where).

  Patch for the above fix.
diff -Naur java.orig/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp java/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp
--- java.orig/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp 2003-09-11 01:40:30.000000000 +0000
+++ java/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp 2003-10-19 17:41:48.000000000 +0000
@@ -49,7 +49,7 @@
   jlong old_value;
   __asm__ volatile ( "pushl %%ebx;mov 4+%1,%%ecx;mov %1,%%ebx;lock;cmpxchg8b (%3);popl %%ebx"
                     : "=A" (old_value)
- : "o" (exchange_value), "A" (compare_value), "r" (dest)
+ : "m" (exchange_value), "A" (compare_value), "r" (dest)
                     : "%ebx", "%ecx", "memory");
   return old_value;
 }
(Incident Review ID: 217806)
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