[LLVMdev] Stack alignment in JIT compiled code

Simon Moll simon.m.moll at googlemail.com
Thu Apr 30 14:18:46 PDT 2009

Hi all,

i am trying to call an aligned function in my host application from jit
compiled bitcode. The call itself is done using an absolute pointer to
the function. The host application's functions make heavy use of SSE
instructions and are thus operate on a stack aligned to 16 byte.

If i call an aligned function in the host application from a frame
running jit compiled code, the alignment property is hurt, causing to
seg faults.

So far, i found no way to denote calls to the host function as aligned
or maintain stack alignment throughout the stack frame of the jit
compiled function. Further, the gcc front end (llvm-g++ (GCC) 4.2.1)
seems to ignore directives such as -mpreferred-stack-boundary.

Somebody gut a clue?

Simon Moll

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