Projects

[Boehm, Hans]

I'm pretty sure you won't catch a Java compiler generating a .class file in
which _Jv_MonitorEnter() and _Jv_MonitorExit() don't nest.  The question is
whether a hand generated .class file, or one generated by some non-Java
compiler should compile correctly.  According to the original version of
"The Java Virtual Machine Specification", I believe the answer was "yes".
Whether that has been changed, I don't know.

I assume this matters in that we are trying to conform to the JVM spec, even
in corner cases like this? 

Hans


-----Original Message-----
From: Jon Olson [ mailto:olson@mmsi.com ]
Sent: Friday, May 05, 2000 5:07 PM
To: Boehm, Hans; Jeff Sturm
Cc: Tom Tromey; green@cygnus.com; java-discuss@sourceware.cygnus.com
Subject: RE: Projects


On Fri, 05 May 2000, Boehm, Hans wrote:
>This assumes that calls to _Jv_MonitorEnter() and _Jv_MonitorExit() nest
>correctly.  That's certainly true for Java source files.  It used to not be
>guaranteed for .class files.  Is it now?
>
>Hans
>

Hmmm... I've compiled many thousands of lines of Java files and 
haven't yet found a .class file that didn't nest properly.  In fact, I
put code into the gcj byte code verifier to abort if they ever didn't nest
properly.  Originally it tripped a few times when I was trying to
get the logic right to munch all the try/catch blocks that release monitors,
but I haven't had it happen for about a year's worth of Java compilation.

I'd sure be interested to see a valid .class file in which monitors don't
properly nest with exceptions.

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