llvm dev - Oct 2009 - [LLVMdev] MallocInst/CallInst bitcast,

Hello,

I'm writing a virtual machine that functions as a sandbox based on llvm. In
order to prevent programs from accessing memory that has not been allocated
to them, I want to replace calls to malloc and free with calls to a logged
functions that will record the memory that is being allocated to the
program. Is it possible to cast/convert a MallocInst or FreeInst to a
CallInst?

Thanks,

Daniel
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Never mind, I used ExecutionEngine's InstallLazyFunctionCreator and
DisableSymbolSearching to cause malloc and free calls to be handled by my
logging functions. Sorry for the unnecessary list mail.

Is it possible to find out the size and beginning pointer of the current
stack frame, from a function operating outside of the virtual machine, but
called by a function within it?

Thanks,

Daniel

2009/10/16 Daniel Waterworth <da.waterworth at googlemail.com>
> Hello,
>
> I'm writing a virtual machine that functions as a sandbox based on
llvm. In
> order to prevent programs from accessing memory that has not been allocated
> to them, I want to replace calls to malloc and free with calls to a logged
> functions that will record the memory that is being allocated to the
> program. Is it possible to cast/convert a MallocInst or FreeInst to a
> CallInst?
>
> Thanks,
>
> Daniel
>
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On Oct 16, 2009, at 4:43 AM, Daniel Waterworth wrote:
> Never mind, I used ExecutionEngine's InstallLazyFunctionCreator and  
> DisableSymbolSearching to cause malloc and free calls to be handled  
> by my logging functions. Sorry for the unnecessary list mail.
No problem, this is a better way to go.  The MallocInst and FreeInst  
instructions are about to be removed from LLVM IR.  Malloc and free  
will be represented normal 'call' instructions.
> Is it possible to find out the size and beginning pointer of the  
> current stack frame, from a function operating outside of the  
> virtual machine, but called by a function within it?
I don't think so.  Typically, applications that need this sort of  
thing get the address of the function and then do a fuzzy disassembly  
of the prolog.

-Chris
>
> Thanks,
>
> Daniel
>
> 2009/10/16 Daniel Waterworth <da.waterworth at googlemail.com>
> Hello,
>
> I'm writing a virtual machine that functions as a sandbox based on  
> llvm. In order to prevent programs from accessing memory that has  
> not been allocated to them, I want to replace calls to malloc and  
> free with calls to a logged functions that will record the memory  
> that is being allocated to the program. Is it possible to cast/ 
> convert a MallocInst or FreeInst to a CallInst?
>
> Thanks,
>
> Daniel
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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