RFR: 8218169 - [AOT] Segmentation fault when running java with AOTed Graal in -Xcomp mode on windows

[dean.long at oracle.com]

With this fix, can we retire os::register_code_area()?

dl

On 2/7/19 7:15 AM, Bob Vandette wrote:
> Please review this fix for a SEGV occurring when AOT is used on Windows.
>
> PROBLEM:
>
> The problem is caused by the fact that we're getting an implicit exception from the .text
> segment of an AOT generated library but the generated code in the DLL does not have
> any structured exception sections or unwind tables. The normal hotspot CodeCache works
> around this limitation by registering the entire code cache with RtlAddFunctionTable. In order
> to do this for AOT generated code, a DynamicCodeData structure would need to be generated
> in the text segment of the AOT library.
>
> BUG:
> https://bugs.openjdk.java.net/browse/JDK-8218169
>
> WEBREV:
> http://cr.openjdk.java.net/~bobv/8218169
>
> SOLUTION:
>
> Rather than modify the AOT implementation to generate a Windows specific data structure that
> requires a jmp out of the DLL code and into Hotspots exception handler, I chose a simpler solution
> that installs a VectoredException handler. This VectoredException handler is only installed if AOT
> is enabled.
>
> This handler examines the pc of the exception. If this pc is determined to be in either the
> codeCache or in AOT generated code, we pass control to the existing exception handler otherwise
> we allow the system to continue searching for other exception handlers.
>
> There were problems in the past with the use of VEH but at that time we made exclusive use of
> VEH and did not use them in conjunction with SEH.  Since I am only passing control to our
> existing handler when the pc is from one of our code sections, other code in the system can
> continue to use SEH.
>
> For more details, please see the bug comments.
>
> Bob.
>
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>
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