llvm dev - Sep 2016 - Bug in 3.9.0 RTDyldMemoryManager.cpp

Hi folks,

I'm still using MCJIT (I know, I know), and I spotted a crash in exception
handling when I moved from llvm 3.8 to llvm 3.9.  I traced it back to EH
frames not being deregistered due to a (typo?) mistake in
RTDyldMemoryManager.cpp:

  void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size)
override {
*    registerEHFramesInProcess(Addr, Size);*
  }

..I overrode the function to call deregister instead of register in my own
MemMgr and all's now well.

The crash manifests itself as a seg fault when a process causes an
exception after JITted code has been removed.

Cheers,

Matt
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Hi Matt,

Thanks very much for catching this. I've fixed it in r283123.

Cheers,
Lang.

On Fri, Sep 30, 2016 at 12:13 PM, Matt Godbolt via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi folks,
>
> I'm still using MCJIT (I know, I know), and I spotted a crash in
exception
> handling when I moved from llvm 3.8 to llvm 3.9.  I traced it back to EH
> frames not being deregistered due to a (typo?) mistake in
> RTDyldMemoryManager.cpp:
>
>   void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size)
> override {
> *    registerEHFramesInProcess(Addr, Size);*
>   }
>
> ..I overrode the function to call deregister instead of register in my own
> MemMgr and all's now well.
>
> The crash manifests itself as a seg fault when a process causes an
> exception after JITted code has been removed.
>
> Cheers,
>
> Matt
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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Sweet! Took me a few hours of head-scratching: I'm glad we can save someone
else the debugging :)

On Mon, Oct 3, 2016 at 12:44 PM Lang Hames <lhames at gmail.com> wrote:

Hi Matt,

Thanks very much for catching this. I've fixed it in r283123.

Cheers,
Lang.

On Fri, Sep 30, 2016 at 12:13 PM, Matt Godbolt via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

Hi folks,

I'm still using MCJIT (I know, I know), and I spotted a crash in exception
handling when I moved from llvm 3.8 to llvm 3.9.  I traced it back to EH
frames not being deregistered due to a (typo?) mistake in
RTDyldMemoryManager.cpp:

  void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size)
override {
*    registerEHFramesInProcess(Addr, Size);*
  }

..I overrode the function to call deregister instead of register in my own
MemMgr and all's now well.

The crash manifests itself as a seg fault when a process causes an
exception after JITted code has been removed.

Cheers,

Matt

_______________________________________________
LLVM Developers mailing list
llvm-dev at lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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