* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
[not found] <CABc96T_0THd_tKzdHSjD-xcPd7=dqoFkr0aRwrdvx-h4s2Hnxg@mail.gmail.com>
@ 2011-08-07 11:00 ` Jie Liu
2011-08-08 14:16 ` Tom Tromey
2011-08-15 14:07 ` Andrew Haley
0 siblings, 2 replies; 11+ messages in thread
From: Jie Liu @ 2011-08-07 11:00 UTC (permalink / raw)
To: gcc-patches, java-patches
Hi,
When I use gcj on an RTOS(RTEMS), Double.parseDouble(null) throw
NumberFormatException, but it should throw NullPointerException. So I
add the patch below:
Index: natVMDouble.cc
===================================================================
--- natVMDouble.cc (revision 172224)
+++ natVMDouble.cc (working copy)
@@ -19,6 +19,7 @@
#include <java/lang/VMDouble.h>
#include <java/lang/Character.h>
#include <java/lang/NumberFormatException.h>
+#include <java/lang/NullPointerException.h>
#include <jvm.h>
#include <stdio.h>
@@ -162,6 +163,9 @@
jdouble
java::lang::VMDouble::parseDouble(jstring str)
{
+ if(str == NULL)
+ throw new NullPointerException();
+
int length = str->length();
while (length > 0
The testsuite/Throw_2.java has been PASS after this patch. what do you
think about this patch?
Thanks,
Jie
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-07 11:00 ` [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException Jie Liu
@ 2011-08-08 14:16 ` Tom Tromey
2011-08-09 17:29 ` Jie Liu
2011-08-15 14:07 ` Andrew Haley
1 sibling, 1 reply; 11+ messages in thread
From: Tom Tromey @ 2011-08-08 14:16 UTC (permalink / raw)
To: Jie Liu; +Cc: gcc-patches, java-patches
>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
Jie> + if(str == NULL)
Jie> + throw new NullPointerException();
Jie> +
Jie> int length = str->length();
Why doesn't 'str->length()' throw the NPE?
Tom
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-08 14:16 ` Tom Tromey
@ 2011-08-09 17:29 ` Jie Liu
2011-08-10 13:34 ` Tom Tromey
0 siblings, 1 reply; 11+ messages in thread
From: Jie Liu @ 2011-08-09 17:29 UTC (permalink / raw)
To: Tom Tromey, java-patches, gcc-patches, Joel Sherrill
Hi Tom,
RTEMS does not have virtual memory management, so there is no error
when access the 0 address on rtems.
So 'str->length()' donot throw NPE and just return an meaningless value.
Ps: There is a test:
http://code.google.com/p/rtemsgcj/source/browse/trunk/algorithm/20110810NPE/?r=127,
npe.c is the main file and *.scn is the output.
Thanks,
Jie
2011/8/8 Tom Tromey <tromey@redhat.com>:
>>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
>
> Jie> + if(str == NULL)
> Jie> + throw new NullPointerException();
> Jie> +
> Jie> int length = str->length();
>
> Why doesn't 'str->length()' throw the NPE?
>
> Tom
>
=========== The first mail, for adding Joel ===========
Hi,
When I use gcj on an RTOS(RTEMS), Double.parseDouble(null) throw
NumberFormatException, but it should throw NullPointerException. So I
add the patch below:
Index: natVMDouble.cc
===================================================================
--- natVMDouble.cc (revision 172224)
+++ natVMDouble.cc (working copy)
@@ -19,6 +19,7 @@
#include <java/lang/VMDouble.h>
#include <java/lang/Character.h>
#include <java/lang/NumberFormatException.h>
+#include <java/lang/NullPointerException.h>
#include <jvm.h>
#include <stdio.h>
@@ -162,6 +163,9 @@
jdouble
java::lang::VMDouble::parseDouble(jstring str)
{
+ if(str == NULL)
+ throw new NullPointerException();
+
int length = str->length();
while (length > 0
The testsuite/Throw_2.java has been PASS after this patch. what do you
think about this patch?
Thanks,
Jie
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-09 17:29 ` Jie Liu
@ 2011-08-10 13:34 ` Tom Tromey
2011-08-10 15:59 ` Jie Liu
0 siblings, 1 reply; 11+ messages in thread
From: Tom Tromey @ 2011-08-10 13:34 UTC (permalink / raw)
To: Jie Liu; +Cc: java-patches, gcc-patches, Joel Sherrill
>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
Jie> RTEMS does not have virtual memory management, so there is no error
Jie> when access the 0 address on rtems.
Jie> So 'str->length()' donot throw NPE and just return an meaningless value.
If you compile the Java parts of the library with -fcheck-references, it
should work. This is something you have to set up as part of the port,
as it is decided at (libgcj-) configure time.
This won't help with the native code. IIRC in the end we just gave up
on that; if you wanted real correctness you would have to add a null
check at every dereference in the C++ code. I believe Andrew had a g++
patch to do this in the compiler, but it was rejected.
Tom
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-10 13:34 ` Tom Tromey
@ 2011-08-10 15:59 ` Jie Liu
2011-08-10 16:41 ` Tom Tromey
0 siblings, 1 reply; 11+ messages in thread
From: Jie Liu @ 2011-08-10 15:59 UTC (permalink / raw)
To: Tom Tromey; +Cc: java-patches, gcc-patches, Joel Sherrill
2011/8/10 Tom Tromey <tromey@redhat.com>:
>>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
>
> Jie> RTEMS does not have virtual memory management, so there is no error
> Jie> when access the 0 address on rtems.
> Jie> So 'str->length()' donot throw NPE and just return an meaningless value.
>
> If you compile the Java parts of the library with -fcheck-references, it
> should work. This is something you have to set up as part of the port,
> as it is decided at (libgcj-) configure time.
>
Thank you very much for the information you provide. :)
I add the following patch for -fcheck-references:
Index: configure.host
===================================================================
--- configure.host (revision 172224)
+++ configure.host (working copy)
@@ -347,8 +347,14 @@
slow_pthread_self=
can_unwind_signal=yes
;;
+ *-*-rtems*)
+ can_unwind_signal=no
+ CHECKREFSPEC=-fcheck-references
+ DIVIDESPEC=-fuse-divide-subroutine
+ ;;
esac
+
case "${host}" in
*-cygwin* | *-mingw*)
fallback_backtrace_h=sysdep/i386/backtrace.h
And we can see the following have -fcheck-references:
/mnt/gcj/mytoolchain/libexec/gcc/i386-rtems/4.7.0/jc1
/tmp/ccYuDgD5.jar -fsource-filename=HelloWorld.java
-fhash-synchronization -fuse-divide-subroutine -fcheck-references
-fuse-boehm-gc -fkeep-inline-functions -quiet -dumpbase
HelloWorld.java -mtune=i386 -march=i386 -auxbase HelloWorld -g -g
-Wall -version -fsaw-java-file
-fbootclasspath=./:/usr/share/java/ecj.jar:/mnt/gcj/mytoolchain/share/java/libgcj-4.7.0.jar
-faux-classpath /tmp/cc6nFx0I.zip -o /tmp/ccCuf7ju.s
GNU Java (GCC) version 4.7.0 20110409 (experimental) (i386-rtems)
But it does not work as we want, is there something wrong?
Thanks,
Jie
> This won't help with the native code. IIRC in the end we just gave up
> on that; if you wanted real correctness you would have to add a null
> check at every dereference in the C++ code. I believe Andrew had a g++
> patch to do this in the compiler, but it was rejected.
>
> Tom
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-10 15:59 ` Jie Liu
@ 2011-08-10 16:41 ` Tom Tromey
2011-08-12 7:39 ` Jie Liu
2011-08-12 17:12 ` Jie Liu
0 siblings, 2 replies; 11+ messages in thread
From: Tom Tromey @ 2011-08-10 16:41 UTC (permalink / raw)
To: Jie Liu; +Cc: java-patches, gcc-patches, Joel Sherrill
>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
Jie> + *-*-rtems*)
Jie> + can_unwind_signal=no
Jie> + CHECKREFSPEC=-fcheck-references
Jie> + DIVIDESPEC=-fuse-divide-subroutine
Jie> + ;;
This part is OK with a ChangeLog entry.
Jie> +
Spurious newline addition.
Jie> But it does not work as we want, is there something wrong?
Did you rebuild all of libgcj?
If you did, then I don't know, you'll have to debug it, sorry.
I vaguely recollect that -fcheck-references adds a check for 'this' at
the start of final methods. If I'm misremembering, then that is
probably the problem.
Tom
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-10 16:41 ` Tom Tromey
@ 2011-08-12 7:39 ` Jie Liu
2011-08-12 16:22 ` Bryce McKinlay
2011-08-12 17:12 ` Jie Liu
1 sibling, 1 reply; 11+ messages in thread
From: Jie Liu @ 2011-08-12 7:39 UTC (permalink / raw)
To: Tom Tromey; +Cc: java-patches, gcc-patches, Joel Sherrill
> Jie> But it does not work as we want, is there something wrong?
>
> Did you rebuild all of libgcj?
Yes. :)
>
> If you did, then I don't know, you'll have to debug it, sorry.
>
> I vaguely recollect that -fcheck-references adds a check for 'this' at
> the start of final methods. If I'm misremembering, then that is
> probably the problem.
>
The method length() is not a final method, as java/lang/String.java line 447:
public int length()
{
return count;
}
Is this the problem?
Thanks,
Jie
> Tom
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-12 7:39 ` Jie Liu
@ 2011-08-12 16:22 ` Bryce McKinlay
0 siblings, 0 replies; 11+ messages in thread
From: Bryce McKinlay @ 2011-08-12 16:22 UTC (permalink / raw)
To: Jie Liu; +Cc: Tom Tromey, java-patches, gcc-patches, Joel Sherrill
On Fri, Aug 12, 2011 at 8:27 AM, Jie Liu <lj8175@gmail.com> wrote:
> The method length() is not a final method, as java/lang/String.java line 447:
>
> public int length()
> {
> return count;
> }
>
> Is this the problem?
As String is a final class, all its methods are implicitly final.
Bryce
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-10 16:41 ` Tom Tromey
2011-08-12 7:39 ` Jie Liu
@ 2011-08-12 17:12 ` Jie Liu
2011-08-14 13:04 ` Tom Tromey
1 sibling, 1 reply; 11+ messages in thread
From: Jie Liu @ 2011-08-12 17:12 UTC (permalink / raw)
To: Tom Tromey; +Cc: java-patches, gcc-patches, Joel Sherrill
> If you did, then I don't know, you'll have to debug it, sorry.
>
> I vaguely recollect that -fcheck-references adds a check for 'this' at
> the start of final methods. If I'm misremembering, then that is
> probably the problem.
In my debug, there appears no check for 'this' at start of String.length():
(gdb) s
java::lang::VMDouble::parseDouble (str=0x0)
at ../../../gcc-trunk/libjava/java/lang/natVMDouble.cc:165
165 int length = str->length();
(gdb) s
java.lang.String.length()int (this=@336e44)
at /mnt/gcj/gcj-rtems-work/gcc-trunk/libjava/java/lang/String.java:451
451 return count;
(gdb) p count
$5 = -268370093
(gdb) p this
$6 = (java.lang.String *) 0x0
Thanks,
Jie
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-12 17:12 ` Jie Liu
@ 2011-08-14 13:04 ` Tom Tromey
0 siblings, 0 replies; 11+ messages in thread
From: Tom Tromey @ 2011-08-14 13:04 UTC (permalink / raw)
To: Jie Liu; +Cc: java-patches, gcc-patches, Joel Sherrill
>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
Jie> In my debug, there appears no check for 'this' at start of String.length():
Yeah, I looked for uses of flag_check_references and didn't see one when
building a method's body. So I guess I mis-remembered this.
In any case, the spot you found is just the tip of the problem. Any
method call in any of the C++ code could potentially have the same
issue.
Tom
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException
2011-08-07 11:00 ` [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException Jie Liu
2011-08-08 14:16 ` Tom Tromey
@ 2011-08-15 14:07 ` Andrew Haley
1 sibling, 0 replies; 11+ messages in thread
From: Andrew Haley @ 2011-08-15 14:07 UTC (permalink / raw)
To: java-patches
On 08/07/2011 12:00 PM, Jie Liu wrote:
> When I use gcj on an RTOS(RTEMS), Double.parseDouble(null) throw
> NumberFormatException, but it should throw NullPointerException. So I
> add the patch below:
>
> Index: natVMDouble.cc
> ===================================================================
> --- natVMDouble.cc (revision 172224)
> +++ natVMDouble.cc (working copy)
> @@ -19,6 +19,7 @@
> #include <java/lang/VMDouble.h>
> #include <java/lang/Character.h>
> #include <java/lang/NumberFormatException.h>
> +#include <java/lang/NullPointerException.h>
> #include <jvm.h>
>
> #include <stdio.h>
> @@ -162,6 +163,9 @@
> jdouble
> java::lang::VMDouble::parseDouble(jstring str)
> {
> + if(str == NULL)
> + throw new NullPointerException();
> +
> int length = str->length();
>
> while (length > 0
>
> The testsuite/Throw_2.java has been PASS after this patch. what do you
> think about this patch?
This patch is not OK, and must not go in.
Look at the comment at the top of Throw_2:
// Check that NullPointerExceptions thrown from library code are
// caught. This detects a number of failures that can be caused by
// libgcj being built incorrectly. In particular, we ensure that a
// SEGV in native (i.e. C++) code in libgcj is handled correctly.
// Regrettably, we cannot guarantee that Double.parseDouble() will
// always be native code, or that it will never be inlined. It could
// be argued that we should add a method to libgcj that will be
// guaranteed forever to be native, but I'm reluctant to add to the
// library for the sole purpose of performing this test.
Andrew.
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2011-08-15 9:48 UTC | newest]
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[not found] <CABc96T_0THd_tKzdHSjD-xcPd7=dqoFkr0aRwrdvx-h4s2Hnxg@mail.gmail.com>
2011-08-07 11:00 ` [PATCH] [JAVA] Double.parseDouble(null) throw NullPointerException Jie Liu
2011-08-08 14:16 ` Tom Tromey
2011-08-09 17:29 ` Jie Liu
2011-08-10 13:34 ` Tom Tromey
2011-08-10 15:59 ` Jie Liu
2011-08-10 16:41 ` Tom Tromey
2011-08-12 7:39 ` Jie Liu
2011-08-12 16:22 ` Bryce McKinlay
2011-08-12 17:12 ` Jie Liu
2011-08-14 13:04 ` Tom Tromey
2011-08-15 14:07 ` Andrew Haley
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