llvm dev - Sep 2016 - How to insert instructions before each function calls?

I'm trying to insert some instructions before each function calls (before
arguments push):
   lea %EAX, label                      ----- new instructions
   mov [ESP+stacksize], %EAX  ----- new instructions
   push arg1
   push arg2
   ...
   push argn
   call callee_name

I am a newbie to LLVM. I tried to use buildMI() to insert the instructions
in the lowercall() function. But I couldn't put these instructions in the
right positions. Is there a way to locate the position by using
MachineBasicBlock iterator?

Any suggestions are appreciated.

Thanks!
Shucai
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Take a look at IRBuilder and SetInsertPoint().

On Sep 3, 2016 18:02, "SHUCAI YAO via llvm-dev" <llvm-dev at
lists.llvm.org>
wrote:
> I'm trying to insert some instructions before each function calls
(before
> arguments push):
>    lea %EAX, label                      ----- new instructions
>    mov [ESP+stacksize], %EAX  ----- new instructions
>    push arg1
>    push arg2
>    ...
>    push argn
>    call callee_name
>
> I am a newbie to LLVM. I tried to use buildMI() to insert the instructions
> in the lowercall() function. But I couldn't put these instructions in
the
> right positions. Is there a way to locate the position by using
> MachineBasicBlock iterator?
>
> Any suggestions are appreciated.
>
> Thanks!
> Shucai
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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So one way might look like this:

IRBuilder<> Builder(&*BB); // BB = Function::iterator OR
IRBuilder<>
Builder(CallInst->getParent());
Builder.SetInsertPoint(CallInst);
InstructionClass *YourNewInstruction builder.CreateInstructionClass(.....); //
InstructionClass = type of
instruction you are inserting

-Ryan




On Sat, Sep 3, 2016 at 6:04 PM, Ryan Taylor <ryta1203 at gmail.com> wrote:
> Take a look at IRBuilder and SetInsertPoint().
>
> On Sep 3, 2016 18:02, "SHUCAI YAO via llvm-dev" <llvm-dev at
lists.llvm.org>
> wrote:
>
>> I'm trying to insert some instructions before each function calls
(before
>> arguments push):
>>    lea %EAX, label                      ----- new instructions
>>    mov [ESP+stacksize], %EAX  ----- new instructions
>>    push arg1
>>    push arg2
>>    ...
>>    push argn
>>    call callee_name
>>
>> I am a newbie to LLVM. I tried to use buildMI() to insert the
>> instructions in the lowercall() function. But I couldn't put these
>> instructions in the right positions. Is there a way to locate the
position
>> by using MachineBasicBlock iterator?
>>
>> Any suggestions are appreciated.
>>
>> Thanks!
>> Shucai
>>
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
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