RFR: JDK-8230776: Javac throws AssertionError in jvm.Gen.visitExec

[Vicente Romero]

Hi Jan,

Please review another iteration of the patch at [1], this one is a bit 
more complex as it addresses several very related bugs together. These 
bugs are [2-6]. The common factor is that javac interrupts compilation 
with an exception or assertion error while compiling a source file that 
extends a fuzzed class file.

Thanks,
Vicente

[1] http://cr.openjdk.java.net/~vromero/8230776/webrev.01/
[2] https://bugs.openjdk.java.net/browse/JDK-8231311
[3] https://bugs.openjdk.java.net/browse/JDK-8230964
[4] https://bugs.openjdk.java.net/browse/JDK-8230963
[5] https://bugs.openjdk.java.net/browse/JDK-8230919
[6] https://bugs.openjdk.java.net/browse/JDK-8230776


On 8/26/20 4:26 AM, Jan Lahoda wrote:
> Hi Vicente,
>
> I am sorry, but I don't think this is a fix on a good place.
>
> The root cause here is that the classfile for Test has an invalid 
> method descriptor for the Test's constructor (returns float instead of 
> void). See JVMS 4.6., descriptor_index. I think it would be much 
> better to validate method descriptors, and reject classfiles with 
> descriptors not adhering to JVMS. The user would then get a much more 
> helpful error, saying something like:
> ---
> Sub.java:1: error: cannot access Test
> class Sub extends Test {}
>                   ^
>   bad class file: 
> /home/jlahoda/src/jdk/jdk/build/linux-x86_64-server-release/nb-jtreg/work/classes/tools/javac/T8230776/AssertionErrorTest.d/Test.class
>     method descriptor invalid for <init>
>     Please remove or make sure it appears in the correct subdirectory 
> of the classpath.
> 1 error
> ---
>
> What do you think?
>
> Jan
>
> On 25. 08. 20 19:23, Vicente Romero wrote:
>> Please review fix for [1] at [2]. The fix is ending the compilation 
>> at the code generation phase if a statement cant be generated and 
>> there is no way for the compilation to continue.
>>
>> Thanks,
>> Vicente
>>
>> [1] https://bugs.openjdk.java.net/browse/JDK-8230776
>> [2] http://cr.openjdk.java.net/~vromero/8230776/webrev.00/