[llvm-dev] How to insert instructions before each function calls?
SHUCAI YAO via llvm-dev
llvm-dev at lists.llvm.org
Mon Sep 19 08:39:00 PDT 2016
Thank you very much. I solved my problems by using the similar structure.
BTW, I saw there is a hacky way to do the relative jump in function
of LowerPATCHABLE_FUNCTION_ENTER. I think directional local symbol can
implement it too:
1. t = getDirectionalLocalSymbol first;
2. jmp t
3. then emit nops
Hope it can help.
On Mon, Sep 5, 2016 at 9:21 PM, Dean Michael Berris <dean.berris at gmail.com>
> > On 5 Sep 2016, at 16:14, SHUCAI YAO <yaos4 at mcmaster.ca> wrote:
> > Hi Dean,
> > Do you have any example for this? I would like have a look at how you
> handle this in XRay if it is possible.
> Yes, this is all upstream -- if you look in lib/CodeGen/XRayInstrument.cpp
> and the associated lowering code for X86 in lib/Target/X86/X86MCInstLower.cpp
> and/or search for PATCHABLE_RET in include/... and lib/... then that should
> give you a better idea of how this works. :)
> -- Dean
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