[llvm-dev] Modified LLVM IR
mats petersson via llvm-dev
llvm-dev at lists.llvm.org
Wed Feb 10 03:01:38 PST 2016
So, I think we need to take one (or a dozen) step(s) back and look at what
you are ACTUALLY trying to do. In other words, your question is a bit of an
XY Question - like someone with a car with a punctured tyre, asking a
mechanic how to undo the wheel nuts, because that's what immediately comes
to mind for taking the wheel off. But you should ask "how do I fix a
puncture" (because the right steps and order of them is more than just undo
the nuts that hold the wheel in place).
So what is your "fix a puncture" goal here?
--
Magts
On 10 February 2016 at 10:49, Sandeep Kumar Singh <deepdondo007 at gmail.com>
wrote:
> Hi,
>
> My requirement is something like as given below,
> a.c => a.obj contains a1() and a2() function
> b.c => b.obj contains b1() and b2() function
> main.c => main.obj call to a1, a2, b1, b2
>
> Now, I want to move a1(), a2() from a.obj to b2.obj and on top of function
> b1()
> When I call b1() from main, it should call first a1, a2 and then function
> definition of b1
>
> Can you please give me some pointers for my requirement.
>
> Thank you in advance.
> Deepika
>
> On Wed, Feb 10, 2016 at 2:54 PM, mats petersson <mats at planetcatfish.com>
> wrote:
>
>> This is the starting point:
>> http://llvm.org/docs/WritingAnLLVMPass.html
>>
>> I suspect you want either a "FunctionPass" or a "BlockPass".
>>
>> The question you stil haven't answered is how you know what you are going
>> to insert function calls for. Inserting the call itself is relatively
>> simple, detecting the right place may or may not be simple - and this is
>> where the above advice may not be at all meaningful - since for example
>> modifying the AST in the Clang part of the compiler may be more suitable,
>> since that is where you have the knowledge of what the original source code
>> looks like, rather than LLVM IR which is more disconnected from the
>> original source.
>>
>> --
>> Mats
>>
>> On 10 February 2016 at 08:07, Sandeep Kumar Singh <deepdondo007 at gmail.com
>> > wrote:
>>
>>> Hi,
>>>
>>> Yes I am looking for IR pass that will do insert call of functions that
>>> defined in another file.
>>> Links/suggestions that guide me to start for adding IR pass will help me
>>> so much.
>>>
>>> Regards,
>>> Deepika
>>>
>>> On Wed, Feb 10, 2016 at 1:03 PM, mats petersson <mats at planetcatfish.com>
>>> wrote:
>>>
>>>> So how do you know what you want to modify (conceptually)?
>>>>
>>>> Have you got a IR pass that you are working on, or are you asking for
>>>> links/suggestions on how to start on one?
>>>>
>>>> --
>>>> Mats
>>>>
>>>> On 10 February 2016 at 04:04, Sandeep Kumar Singh <
>>>> deepdondo007 at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I want to call/add some functions(that defined in another file) on top
>>>>> of some functions, and reflect the same changes in object file.
>>>>> No, I am not looking for contractor.
>>>>>
>>>>> Thanks,
>>>>> Deepika
>>>>>
>>>>> On Tue, Feb 9, 2016 at 7:04 PM, mats petersson <mats at planetcatfish.com
>>>>> > wrote:
>>>>>
>>>>>> What is the condition for adding this code?
>>>>>>
>>>>>> What have you tried so far? [Or are you looking for a contractor that
>>>>>> can write code for you - I'm not sure this is quite the right place for
>>>>>> that, but there are probably some people like that on this mailing list]
>>>>>>
>>>>>> --
>>>>>> Mats
>>>>>>
>>>>>> On 9 February 2016 at 09:34, Sandeep Kumar Singh via llvm-dev <
>>>>>> llvm-dev at lists.llvm.org> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I want to edit LLVM generated IR file, like as given below,
>>>>>>>
>>>>>>> Original LLVM IR file,
>>>>>>> @.str2 = private unnamed_addr constant [17 x i8] c"\0AI am in
>>>>>>> one_11\0A\00", align 1
>>>>>>>
>>>>>>> ; Function Attrs: nounwind
>>>>>>> define i32 @one_1(i32 %ivar1, i32 %ivar2) #0 {
>>>>>>> entry:
>>>>>>> %ivar1.addr = alloca i32, align 4
>>>>>>> %ivar2.addr = alloca i32, align 4
>>>>>>> %isum = alloca i32, align 4
>>>>>>> store i32 %ivar1, i32* %ivar1.addr, align 4
>>>>>>> store i32 %ivar2, i32* %ivar2.addr, align 4
>>>>>>> store i32 0, i32* %isum, align 4
>>>>>>> %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds
>>>>>>> ([16 x i8]* @.str, i32 0, i32 0)) #1
>>>>>>> %0 = load i32* %ivar1.addr, align 4
>>>>>>> %1 = load i32* %ivar2.addr, align 4
>>>>>>> %call1 = call i32 @one_11(i32 %0, i32 %1)
>>>>>>> store i32 %call1, i32* %isum, align 4
>>>>>>> %2 = load i32* %isum, align 4
>>>>>>> ret i32 %2
>>>>>>> }
>>>>>>>
>>>>>>> Modified LLVM IR file,
>>>>>>> @.str2 = private unnamed_addr constant [17 x i8] c"\0AI am in
>>>>>>> one_11\0A\00", align 1
>>>>>>> @.str3 = private unnamed_addr constant [17 x i8] c"\0AI am in
>>>>>>> one_12\0A\00", align 1
>>>>>>>
>>>>>>> ; Function Attrs: nounwind
>>>>>>> define i32 @one_1(i32 %ivar1, i32 %ivar2) #0 {
>>>>>>> entry:
>>>>>>> %ivar1.addr = alloca i32, align 4
>>>>>>> %ivar2.addr = alloca i32, align 4
>>>>>>> %isum = alloca i32, align 4
>>>>>>> store i32 %ivar1, i32* %ivar1.addr, align 4
>>>>>>> store i32 %ivar2, i32* %ivar2.addr, align 4
>>>>>>> store i32 0, i32* %isum, align 4
>>>>>>> %call1 = call i32 @one_12(i32 %0, i32 %1) <==
>>>>>>> store i32 %call1, i32* %isum, align <==
>>>>>>> %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds
>>>>>>> ([16 x i8]* @.str, i32 0, i32 0)) #1
>>>>>>> %0 = load i32* %ivar1.addr, align 4
>>>>>>> %1 = load i32* %ivar2.addr, align 4
>>>>>>> %call2 = call i32 @one_11(i32 %0, i32 %1) <==
>>>>>>> store i32 %call2, i32* %isum, align 4 <==
>>>>>>> %2 = load i32* %isum, align 4
>>>>>>> ret i32 %2
>>>>>>> }
>>>>>>>
>>>>>>> With llc tool, I want to generate object file for modified llvm ir
>>>>>>> file and it should call function
>>>>>>> first "one_12"" and then function "one_11".
>>>>>>>
>>>>>>> Can someone please tell me how I can do my above requirement.
>>>>>>>
>>>>>>> Thanks in advance,
>>>>>>> Deepika
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> LLVM Developers mailing list
>>>>>>> llvm-dev at lists.llvm.org
>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> Thanks and Regards,
>>>>> Sandeep Kumar Singh
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>>
>>> Thanks and Regards,
>>> Sandeep Kumar Singh
>>>
>>
>>
>
>
> --
>
> Thanks and Regards,
> Sandeep Kumar Singh
>
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