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Daniel Moya via llvm-dev

2018-Sep-06 00:11 UTC

[llvm-dev] Replacing a function from one module into another one

Hi Philip,

Thanks for the reference, I was able to follow it and copy the code that I
saw necessary, but I still have some issues (references are still not
updated). I created the function:

void populateVMap(llvm::ValueToValueMapTy &VMap, llvm::Function *fOld,
llvm::Function *fNew) {
  llvm::Function::arg_iterator DestI = fOld->arg_begin();
  for (llvm::Function::const_arg_iterator J = fNew->arg_begin(); J
!fNew->arg_end();
       ++J) {
    DestI->setName(J->getName());
    VMap[&*J] = &*DestI++;
  }
}

The same as in *CloneModule*, then I have this code:

llvm::Function *fNew = nMod->getFunction(nFName);
llvm::Function *fOld = oMod->getFunction(oFName);

fOld->dropAllReferences();
fOld->deleteBody();

llvm::ValueToValueMapTy VMap;
populateVMap(VMap, fOld, fNew);
bool ModuleArg = true;
llvm::SmallVector<llvm::ReturnInst*, 8> Returns;
llvm::CloneFunctionInto(fOld, fNew, VMap, ModuleArg, Returns);
if (fNew->hasPersonalityFn())
   fOld->setPersonalityFn(llvm::MapValue(fNew->getPersonalityFn(), VMap));

But after running the code, I still get the error: *Use still stuck around
after Def is destroyed*

Which means that the instructions moved from *fNew* still refer to the
arguments of *fNew* instead of the "mapped" (supposedly) ones in
*fOld*. I
have some ideas of what could be going on:

   1. I'm not populating correctly the VMap argument, although I
wouldn't
   know how to do it differently since I literally copied it from the
   *CloneModule*.
   2. I have to still add more instruction either before or after
   *CloneFunctionInto*, for example in *CloneModule* they call the function
  
[copyComdat](*http://llvm.org/doxygen/CloneModule_8cpp.html#a04b8f04da3f1b0bf1c9a2802f73e2d05
  
<http://llvm.org/doxygen/CloneModule_8cpp.html#a04b8f04da3f1b0bf1c9a2802f73e2d05>*),
   but I don't know if it's necessary (I guess no because it's only
defined in
   CloneModule.cpp), they also iterate over global alias and functions, but
   since I'm only concerned in the arguments of one function, I guess I
don't
   have to worry about that.
   3. Perhaps what you mentioned before "Only operations across
   LLVMContexts are tricky" has something to do, because the operation is
   between modules of different files, I'm guessing they have different
   Contexts too, what could be done in this case?

Finally, I also tried moving the BasicBlocks manually and got the same
error "Use still stuck..", and then tried
calling llvm::RemapFunction afterwards with the populated VMap, but always
got the error:

Assertion `(Flags & RF_IgnoreMissingLocals) && "Referenced
value not in
value map!"' failed

Which left me clueless since the mapping worked in the *CloneFunctionInto*
(the program executed fine, the error "Use still stuck" happened at
the
program's end) but not in this *RemapFunction*. Anyways, I believe
*CloneFunctionInto* should do this remap work so I shouldn't have to call
*RemapFunction*. Any guideline would be greatly appreciated, it has been a
long suffering.

Regards,
Daniel Moya


El mié., 5 de sep. de 2018 a la(s) 11:15, Philip Pfaffe (
philip.pfaffe at gmail.com) escribió:
> Hi Daniel,
>
> the implementation of [CloneModule](
> http://llvm.org/doxygen/CloneModule_8cpp_source.html) should be a good
> example. Generally all you need to do in your case is map old arguments to
> new arguments.
>
> Cheers,
> Philip
>
> On Tue, Sep 4, 2018 at 1:18 PM Daniel Moya <danielmscr1994 at
gmail.com>
> wrote:
>
>> Hi Philip,
>>
>> Thank you very much for your answer, the vector declaration example
>> worked. I'm pretty sure the ValueToValueMapTy is the last thing I
need
>> because I even saw there is another function that could help me llvm*:*
>> :RemapFunction
>>
<http://llvm.org/doxygen/namespacellvm.html#addf0183e92893bdbcde00fc9091dda93>;
>> but my problem is that I don't know how to populate the
ValueToValueMapTy
>> (VMap) and I couldn't find a single complete example on the
internet. To
>> begin with, as the name implies (and also from some errors that I got)
the
>> ValueToValueMapTy takes a std::pair<llvm::Value, llvm::Value>,
but what I
>> need is to map the arguments (llvm::Attribute) of both functions (the
first
>> argument of foo2 is equivalent to the first argument of foo3, and so
on),
>> however, apparently there's no transformation from a
llvm::Attribute to a
>> llvm::Value. I'm using the function getAttribute
>>
<http://llvm.org/doxygen/classllvm_1_1Function.html#ab2a5fc8baaee7e74dbe47d848508745a>
>>  (unsigned <http://llvm.org/doxygen/classunsigned.html> i,
StringRef
>> <http://llvm.org/doxygen/classllvm_1_1StringRef.html> Kind
>>
<http://llvm.org/doxygen/ARMAsmParser_8cpp.html#a5ec5335889cd241b0ccfd4e4e58cf52e>
>> ) const
>>
<http://llvm.org/doxygen/AArch64PromoteConstant_8cpp.html#a90f8350fecae261c25be85d38b451bff>
to
>> get the attributes, but I don't even understand why is it required
to give
>> the StringRef
<http://llvm.org/doxygen/classllvm_1_1StringRef.html> Kind
>>
<http://llvm.org/doxygen/ARMAsmParser_8cpp.html#a5ec5335889cd241b0ccfd4e4e58cf52e>
if
>> what I need is just the attribute of the function in the *i *position.
>> I'm really thankful for the quick responses and for the attention
received.
>>
>> Regards,
>> Daniel Moya
>>
>>
>>
>>
>>
>> El lun., 3 de sep. de 2018 a la(s) 18:42, Philip Pfaffe (
>> philip.pfaffe at gmail.com) escribió:
>>
>>> Hi Daniel,
>>>
>>> CloneFunctionInto wants to tell you about the new
ReturnInstructions it
>>> produced, you're expected to pass a vector for this purpose.
You're free to
>>> ignore these values, though, but you still have to pass that
>>> vector:  SmallVector<ReturnInst*, 8> Returns;
>>>
>>> For the argument remapping, you're supposed to pre-populate the
VMap you
>>> pass with the appropriate argument-to-argument mapping.
>>>
>>> It's perfectly fine to use CloneFunctionInto across modules,
btw. Only
>>> operations across LLVMContexts are tricky.
>>>
>>> Cheers,
>>> Philip
>>>
>>> On Mon, Sep 3, 2018 at 6:31 PM Daniel Moya via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Thank you Ahmad,
>>>>
>>>> I figured out that, although the type of both p(oInst) and
p(nInst)
>>>> were the same, I had to:
>>>>
>>>> for (unsigned int i = 0; i <
callOInst->getNumArgOperands(); i++) {
>>>>
callOInst->getArgOperand(i)->mutateType(callNInst->getArgOperand(i)->getType());
>>>> }
>>>>
>>>> that solves the issue at the calling instruction in the main
function,
>>>> but now I see that *linkModules* does not work for me (it's
a mess to
>>>> bring all the other unnecessary functions from the reference
module) so
>>>> what I need is to directly move one function from one module to
another
>>>> one. I'm still facing the issue with the
*llvm::SmallVectorImpl<
>>>> llvm::ReturnInst *> &Returns *argument for the
*CloneFunctionInto, *can
>>>> anyone please give an example of use of that function? I guess
that's the
>>>> only way because otherwise if I move the blocks from foo3 in
the refModule
>>>> to the oldModule, the references of the moved block still point
to the
>>>> arguments of foo3 defined in the refModule, and I don't
know how to go
>>>> instruction by instruction in all the moved blocks and correct
the
>>>> reference to point to the arguments in the oldModule's new
function, this
>>>> also sounds very messy and complicated.
>>>>
>>>>
>>>> Regards,
>>>> Daniel Moya
>>>>
>>>>
>>>>
>>>>
>>>> El dom., 2 de sep. de 2018 a la(s) 23:18, Ahmad Nouralizadeh
Khorrami (
>>>> ahmad.llvm at gmail.com) escribió:
>>>>
>>>>> Hi Daniel,
>>>>> The answer was for your first thread. The benefits are
outlined in the
>>>>> repository, but your problem is still there. I'm not
sure. But this looks
>>>>> similar to my recent problem. I think that a bitcast will
solve the
>>>>> problem. The types after the linking process may have
different names but
>>>>> the same contents. The links to the answers are as follows:
>>>>>
http://lists.llvm.org/pipermail/llvm-dev/2018-August/125413.html
>>>>>
>>>>>
https://stackoverflow.com/questions/51894129/convert-function-pointer-call-to-function-call-at-the-ir-level
>>>>> Regards.
>>>>>
>>>>> On Sun, 2 Sep 2018 at 23:30, Daniel Moya <danielmscr1994
at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi Ahmad,
>>>>>>
>>>>>> What does that tool does besides what LLVM linker
already does? I
>>>>>> don't think my problem is in linking both modules,
I think LLVM linker does
>>>>>> the job for me, the issue is when changing the called
function to call
>>>>>> another function (in the example previously provided,
to change it from
>>>>>> foo2 to foo3, and adjusting the function
parameter's references).
>>>>>>
>>>>>> Regards,
>>>>>> Daniel Moya
>>>>>>
>>>>>> El dom., 2 de sep. de 2018 a la(s) 17:00, Ahmad
Nouralizadeh Khorrami
>>>>>> (ahmad.llvm at gmail.com) escribió:
>>>>>>
>>>>>>> Hi.
>>>>>>> Besides the LLVM linker, you can also use this
tool:
>>>>>>> https://github.com/travitch/whole-program-llvm
>>>>>>> It links all the modules and produces a single
module containing
>>>>>>> every function.
>>>>>>> Regards.
>>>>>>>
>>>>>>> On Sun, 2 Sep 2018 at 16:57, Daniel Moya via
llvm-dev <
>>>>>>> llvm-dev at lists.llvm.org> wrote:
>>>>>>>
>>>>>>>> Hello and thanks for the answer,
>>>>>>>>
>>>>>>>> I'm still facing issues, I'll do my
best to explain my situation,
>>>>>>>> as I explained, I have two modules, each one
with its own main and
>>>>>>>> functions, I would like to replace in the
*oldModule* a function
>>>>>>>> call that is calling *foo2* (defined in
*oldModule*) to instead
>>>>>>>> call *foo3*, which is defined in the
*refModule.  *So in summary,
>>>>>>>> I have:
>>>>>>>>
>>>>>>>>    1. The original instruction call, defined in
the main function
>>>>>>>>    of the oldModule, who is a calling function
to foo2, I'll name it
>>>>>>>>    *oInst *(original Instruction)
>>>>>>>>    2. The "new" instruction call,
defined in the main function of
>>>>>>>>    the refModule, who is a calling function to
foo3, I'll name it
>>>>>>>>    *nInst* (new Instruction)
>>>>>>>>    3. The foo2 function definition, defined in
the oldModule, I'll
>>>>>>>>    name it *oFunc *(original Function)
>>>>>>>>    4. The foo3 function definition, defined in
the refModule, I'll
>>>>>>>>    name it *nFunc* (new Function)
>>>>>>>>    5. I have the parameters (or arguments?) of
both functions,
>>>>>>>>    both in the calling instruction and in the
function's definition, which
>>>>>>>>    I'll refer to as *p(oInst)*, *p(nInst)*,
*p(oFunc)*, *p(nFunc) *(the
>>>>>>>>    parameters of)
>>>>>>>>    6. For testing purposes, both foo2 and foo3
and defined
>>>>>>>>    identical, same returning type,
parameter's type and even the same
>>>>>>>>    variable's name in the IR.
>>>>>>>>
>>>>>>>> So after calling the *llvm::LinkerlinkModules*
function, I did:
>>>>>>>>
>>>>>>>> 1. First attempt:
>>>>>>>>
>>>>>>>>    1. llvm::CallInst *callOInst
>>>>>>>>    static_cast<llvm::CallInst*>(oInst); 
// I cast the* oInst* to
>>>>>>>>    a llvm::CallInst
>>>>>>>>    2. callOInst->setCalledFunction(nFunc);
// now *oInst* should
>>>>>>>>    call nFunc
>>>>>>>>
>>>>>>>> Error:
>>>>>>>> Call parameter type does not match function
signature!
>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>> i32 %call1 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>
>>>>>>>> So even though the parameters are the same
type, and defined
>>>>>>>> identically in both modules, the *p(oInst)*
apparently does not
>>>>>>>> match the *p(nFunc)*.
>>>>>>>>
>>>>>>>> 2. Second attempt:
>>>>>>>>
>>>>>>>>    1. llvm::Instruction *nCloneInst =
nInst->clone(); //Clone of
>>>>>>>>    the *nInst*, to avoid remove it from the
refModule
>>>>>>>>    2. nCloneInst->insertAfter(oInst); //
I'll bring the nInst
>>>>>>>>    because I know *p(nInst)* and *p(nFunc)*
match
>>>>>>>>    3.
nCloneInst->mutateType(oInst->getType()); //Idk why I have
>>>>>>>>    to this, but necessary for next line
>>>>>>>>    4. oInst->replaceAllUsesWith(nCloneInst);
>>>>>>>>    5. oInst->dropAllReferences();
>>>>>>>>    6. oInst->eraseFromParent();
>>>>>>>>
>>>>>>>> Error:
>>>>>>>> Instruction does not dominate all uses!
>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>> %2 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>
>>>>>>>> Great, now the *p(nInst)* are still referring
to their definition
>>>>>>>> in the refModule, so either I bring those
instructions too (which sounds
>>>>>>>> really messy) or somehow I change the
*p(nInst)* to refer to the
>>>>>>>> instructions in oldModule, which in my case are
actually defined the same
>>>>>>>> (but apparently the references don't change
based on the name being the
>>>>>>>> same in both modules).
>>>>>>>>
>>>>>>>> 3. Third attempt:
>>>>>>>>
>>>>>>>>    1. The same 1-4 steps as before, from
cloning instruction to
>>>>>>>>    replaceAllUsesWith
>>>>>>>>    2. llvm::CallInst *callNInst
>>>>>>>>   
static_cast<llvm::CallInst*>(nCloneInst);
>>>>>>>>    3. llvm::CallInst *callOInst
>>>>>>>>    static_cast<llvm::CallInst*>(oInst);
// cast both *oInst* and
>>>>>>>>    *nInst*
>>>>>>>>    4. for (unsigned int i = 0; i <
callOInst->getNumArgOperands();
>>>>>>>>    i++) {
callNInst->setArgOperand(i,callOInst->getArgOperand(i)); } //replace
>>>>>>>>    *p(nInst)* with *p(oInst)*
>>>>>>>>    5. The same 5-6 steps as before, drop and
erase
>>>>>>>>
>>>>>>>> Error:
>>>>>>>> Call parameter type does not match function
signature!
>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>> i32  %2 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>
>>>>>>>> So back to the first problem, the *p(nInst)
*(now converted to
>>>>>>>> *p(oInst)*) apparently does not match the
*p(nFunc)*.
>>>>>>>>
>>>>>>>> I also looked into the *CloneFunctionInto
*function, but I didn't
>>>>>>>> understand the arguments of it, and there's
really no documentation or
>>>>>>>> examples that I could find on the internet.
Specifically, I have troubles
>>>>>>>> with *llvm::SmallVectorImpl<
llvm::ReturnInst *> &Returns *argument,
>>>>>>>> I don't know how to initialize it, it
doesn't have a 0 argument constructor
>>>>>>>> and if I try:
>>>>>>>>
>>>>>>>> llvm::SmallVectorImpl< llvm::ReturnInst
*> ReturnsArg >>>>>>>> llvm::SmallVectorImpl<
llvm::ReturnInst *>(2); // Just as an example
>>>>>>>>
>>>>>>>> It says that constructor is protected. I
didn't want to go further
>>>>>>>> since I'm clueless on how to properly use
this function, and I'm even not
>>>>>>>> completely sure if it would fix all the
troubles that I've been having with
>>>>>>>> the other three attempts.
>>>>>>>>
>>>>>>>> Btw, all these errors happen when I try to run
(through JIT) the
>>>>>>>> module, a workaround that I know that I can do
for all my attempts is just
>>>>>>>> to dump the module to a file, and then reload
it and execute it (I know it
>>>>>>>> works since in both oldModule and refModule I
use the same IR variable's
>>>>>>>> names) but I would like to do the work the
*right* way and not
>>>>>>>> having to inefficiently dump a file just to
reload it again and get all the
>>>>>>>> references right.
>>>>>>>>
>>>>>>>> Thanks for the help in advance, I'll be
really grateful for any
>>>>>>>> advice or light in my situation.
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Daniel Moya
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> El mar., 28 de ago. de 2018 a la(s) 20:26,
Friedman, Eli (
>>>>>>>> efriedma at codeaurora.org) escribió:
>>>>>>>>
>>>>>>>>> On 8/27/2018 10:37 AM, Daniel Moya via
llvm-dev wrote:
>>>>>>>>> > Hello LLVM Developers,
>>>>>>>>> >
>>>>>>>>> > I'm trying to replace a function
defined in one module into
>>>>>>>>> another
>>>>>>>>> > module (different files). The first
issue I ran into was that
>>>>>>>>> > llvm::Function does not have a method
"moveBefore" or
>>>>>>>>> "moveAfter" as
>>>>>>>>> > the llvm::BasicBlock or
llvm::Instruction do, so I figured I
>>>>>>>>> would
>>>>>>>>> > just move the BasicBlocks of the
replacing function into the
>>>>>>>>> function
>>>>>>>>> > that was being replaced, and then
eliminate the original
>>>>>>>>> BasicBlocks.
>>>>>>>>>
>>>>>>>>> Cross-module operations are tricky in
general; I'd suggest using
>>>>>>>>> the
>>>>>>>>> Linker::linkModules API if possible.
>>>>>>>>>
>>>>>>>>> -Eli
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Employee of Qualcomm Innovation Center,
Inc.
>>>>>>>>> Qualcomm Innovation Center, Inc. is a
member of Code Aurora Forum,
>>>>>>>>> a Linux Foundation Collaborative Project
>>>>>>>>>
>>>>>>>>>
_______________________________________________
>>>>>>>> LLVM Developers mailing list
>>>>>>>> llvm-dev at lists.llvm.org
>>>>>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>>>>
>>>>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
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Philip Pfaffe via llvm-dev

2018-Sep-06 09:36 UTC

head link

[llvm-dev] Replacing a function from one module into another one

Hi Daniel,

when and where are you getting that error? Can you paste the full code?

Cheers,
Philip

On Thu, Sep 6, 2018 at 2:11 AM Daniel Moya <danielmscr1994 at gmail.com>
wrote:
> Hi Philip,
>
> Thanks for the reference, I was able to follow it and copy the code that I
> saw necessary, but I still have some issues (references are still not
> updated). I created the function:
>
> void populateVMap(llvm::ValueToValueMapTy &VMap, llvm::Function *fOld,
> llvm::Function *fNew) {
>   llvm::Function::arg_iterator DestI = fOld->arg_begin();
>   for (llvm::Function::const_arg_iterator J = fNew->arg_begin(); J !>
fNew->arg_end();
>        ++J) {
>     DestI->setName(J->getName());
>     VMap[&*J] = &*DestI++;
>   }
> }
>
> The same as in *CloneModule*, then I have this code:
>
> llvm::Function *fNew = nMod->getFunction(nFName);
> llvm::Function *fOld = oMod->getFunction(oFName);
>
> fOld->dropAllReferences();
> fOld->deleteBody();
>
> llvm::ValueToValueMapTy VMap;
> populateVMap(VMap, fOld, fNew);
> bool ModuleArg = true;
> llvm::SmallVector<llvm::ReturnInst*, 8> Returns;
> llvm::CloneFunctionInto(fOld, fNew, VMap, ModuleArg, Returns);
> if (fNew->hasPersonalityFn())
>    fOld->setPersonalityFn(llvm::MapValue(fNew->getPersonalityFn(),
VMap));
>
> But after running the code, I still get the error: *Use still stuck
> around after Def is destroyed*
>
> Which means that the instructions moved from *fNew* still refer to the
> arguments of *fNew* instead of the "mapped" (supposedly) ones in
*fOld*.
> I have some ideas of what could be going on:
>
>    1. I'm not populating correctly the VMap argument, although I
wouldn't
>    know how to do it differently since I literally copied it from the
>    *CloneModule*.
>    2. I have to still add more instruction either before or after
>    *CloneFunctionInto*, for example in *CloneModule* they call the
>    function
[copyComdat](*http://llvm.org/doxygen/CloneModule_8cpp.html#a04b8f04da3f1b0bf1c9a2802f73e2d05
>   
<http://llvm.org/doxygen/CloneModule_8cpp.html#a04b8f04da3f1b0bf1c9a2802f73e2d05>*),
>    but I don't know if it's necessary (I guess no because it's
only defined in
>    CloneModule.cpp), they also iterate over global alias and functions, but
>    since I'm only concerned in the arguments of one function, I guess I
don't
>    have to worry about that.
>    3. Perhaps what you mentioned before "Only operations across
>    LLVMContexts are tricky" has something to do, because the operation
is
>    between modules of different files, I'm guessing they have different
>    Contexts too, what could be done in this case?
>
> Finally, I also tried moving the BasicBlocks manually and got the same
> error "Use still stuck..", and then tried
> calling llvm::RemapFunction afterwards with the populated VMap, but always
> got the error:
>
> Assertion `(Flags & RF_IgnoreMissingLocals) && "Referenced
value not in
> value map!"' failed
>
> Which left me clueless since the mapping worked in the *CloneFunctionInto*
> (the program executed fine, the error "Use still stuck" happened
at the
> program's end) but not in this *RemapFunction*. Anyways, I believe
> *CloneFunctionInto* should do this remap work so I shouldn't have to
call
> *RemapFunction*. Any guideline would be greatly appreciated, it has been
> a long suffering.
>
> Regards,
> Daniel Moya
>
>
> El mié., 5 de sep. de 2018 a la(s) 11:15, Philip Pfaffe (
> philip.pfaffe at gmail.com) escribió:
>
>> Hi Daniel,
>>
>> the implementation of [CloneModule](
>> http://llvm.org/doxygen/CloneModule_8cpp_source.html) should be a good
>> example. Generally all you need to do in your case is map old arguments
to
>> new arguments.
>>
>> Cheers,
>> Philip
>>
>> On Tue, Sep 4, 2018 at 1:18 PM Daniel Moya <danielmscr1994 at
gmail.com>
>> wrote:
>>
>>> Hi Philip,
>>>
>>> Thank you very much for your answer, the vector declaration example
>>> worked. I'm pretty sure the ValueToValueMapTy is the last thing
I need
>>> because I even saw there is another function that could help me
llvm*:*
>>> :RemapFunction
>>>
<http://llvm.org/doxygen/namespacellvm.html#addf0183e92893bdbcde00fc9091dda93>;
>>> but my problem is that I don't know how to populate the
ValueToValueMapTy
>>> (VMap) and I couldn't find a single complete example on the
internet. To
>>> begin with, as the name implies (and also from some errors that I
got) the
>>> ValueToValueMapTy takes a std::pair<llvm::Value,
llvm::Value>, but what I
>>> need is to map the arguments (llvm::Attribute) of both functions
(the first
>>> argument of foo2 is equivalent to the first argument of foo3, and
so on),
>>> however, apparently there's no transformation from a
llvm::Attribute to a
>>> llvm::Value. I'm using the function getAttribute
>>>
<http://llvm.org/doxygen/classllvm_1_1Function.html#ab2a5fc8baaee7e74dbe47d848508745a>
>>>  (unsigned <http://llvm.org/doxygen/classunsigned.html> i,
StringRef
>>> <http://llvm.org/doxygen/classllvm_1_1StringRef.html> Kind
>>>
<http://llvm.org/doxygen/ARMAsmParser_8cpp.html#a5ec5335889cd241b0ccfd4e4e58cf52e>
>>> ) const
>>>
<http://llvm.org/doxygen/AArch64PromoteConstant_8cpp.html#a90f8350fecae261c25be85d38b451bff>
to
>>> get the attributes, but I don't even understand why is it
required to give
>>> the StringRef
<http://llvm.org/doxygen/classllvm_1_1StringRef.html> Kind
>>>
<http://llvm.org/doxygen/ARMAsmParser_8cpp.html#a5ec5335889cd241b0ccfd4e4e58cf52e>
if
>>> what I need is just the attribute of the function in the *i
*position.
>>> I'm really thankful for the quick responses and for the
attention received.
>>>
>>> Regards,
>>> Daniel Moya
>>>
>>>
>>>
>>>
>>>
>>> El lun., 3 de sep. de 2018 a la(s) 18:42, Philip Pfaffe (
>>> philip.pfaffe at gmail.com) escribió:
>>>
>>>> Hi Daniel,
>>>>
>>>> CloneFunctionInto wants to tell you about the new
ReturnInstructions it
>>>> produced, you're expected to pass a vector for this
purpose. You're free to
>>>> ignore these values, though, but you still have to pass that
>>>> vector:  SmallVector<ReturnInst*, 8> Returns;
>>>>
>>>> For the argument remapping, you're supposed to pre-populate
the VMap
>>>> you pass with the appropriate argument-to-argument mapping.
>>>>
>>>> It's perfectly fine to use CloneFunctionInto across
modules, btw. Only
>>>> operations across LLVMContexts are tricky.
>>>>
>>>> Cheers,
>>>> Philip
>>>>
>>>> On Mon, Sep 3, 2018 at 6:31 PM Daniel Moya via llvm-dev <
>>>> llvm-dev at lists.llvm.org> wrote:
>>>>
>>>>> Thank you Ahmad,
>>>>>
>>>>> I figured out that, although the type of both p(oInst) and
p(nInst)
>>>>> were the same, I had to:
>>>>>
>>>>> for (unsigned int i = 0; i <
callOInst->getNumArgOperands(); i++) {
>>>>>
callOInst->getArgOperand(i)->mutateType(callNInst->getArgOperand(i)->getType());
>>>>> }
>>>>>
>>>>> that solves the issue at the calling instruction in the
main function,
>>>>> but now I see that *linkModules* does not work for me
(it's a mess to
>>>>> bring all the other unnecessary functions from the
reference module) so
>>>>> what I need is to directly move one function from one
module to another
>>>>> one. I'm still facing the issue with the
*llvm::SmallVectorImpl<
>>>>> llvm::ReturnInst *> &Returns *argument for the
*CloneFunctionInto, *can
>>>>> anyone please give an example of use of that function? I
guess that's the
>>>>> only way because otherwise if I move the blocks from foo3
in the refModule
>>>>> to the oldModule, the references of the moved block still
point to the
>>>>> arguments of foo3 defined in the refModule, and I don't
know how to go
>>>>> instruction by instruction in all the moved blocks and
correct the
>>>>> reference to point to the arguments in the oldModule's
new function, this
>>>>> also sounds very messy and complicated.
>>>>>
>>>>>
>>>>> Regards,
>>>>> Daniel Moya
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> El dom., 2 de sep. de 2018 a la(s) 23:18, Ahmad
Nouralizadeh Khorrami (
>>>>> ahmad.llvm at gmail.com) escribió:
>>>>>
>>>>>> Hi Daniel,
>>>>>> The answer was for your first thread. The benefits are
outlined in
>>>>>> the repository, but your problem is still there.
I'm not sure. But this
>>>>>> looks similar to my recent problem. I think that a
bitcast will solve the
>>>>>> problem. The types after the linking process may have
different names but
>>>>>> the same contents. The links to the answers are as
follows:
>>>>>>
http://lists.llvm.org/pipermail/llvm-dev/2018-August/125413.html
>>>>>>
>>>>>>
https://stackoverflow.com/questions/51894129/convert-function-pointer-call-to-function-call-at-the-ir-level
>>>>>> Regards.
>>>>>>
>>>>>> On Sun, 2 Sep 2018 at 23:30, Daniel Moya
<danielmscr1994 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Ahmad,
>>>>>>>
>>>>>>> What does that tool does besides what LLVM linker
already does? I
>>>>>>> don't think my problem is in linking both
modules, I think LLVM linker does
>>>>>>> the job for me, the issue is when changing the
called function to call
>>>>>>> another function (in the example previously
provided, to change it from
>>>>>>> foo2 to foo3, and adjusting the function
parameter's references).
>>>>>>>
>>>>>>> Regards,
>>>>>>> Daniel Moya
>>>>>>>
>>>>>>> El dom., 2 de sep. de 2018 a la(s) 17:00, Ahmad
Nouralizadeh
>>>>>>> Khorrami (ahmad.llvm at gmail.com) escribió:
>>>>>>>
>>>>>>>> Hi.
>>>>>>>> Besides the LLVM linker, you can also use this
tool:
>>>>>>>> https://github.com/travitch/whole-program-llvm
>>>>>>>> It links all the modules and produces a single
module containing
>>>>>>>> every function.
>>>>>>>> Regards.
>>>>>>>>
>>>>>>>> On Sun, 2 Sep 2018 at 16:57, Daniel Moya via
llvm-dev <
>>>>>>>> llvm-dev at lists.llvm.org> wrote:
>>>>>>>>
>>>>>>>>> Hello and thanks for the answer,
>>>>>>>>>
>>>>>>>>> I'm still facing issues, I'll do my
best to explain my situation,
>>>>>>>>> as I explained, I have two modules, each
one with its own main and
>>>>>>>>> functions, I would like to replace in the
*oldModule* a function
>>>>>>>>> call that is calling *foo2* (defined in
*oldModule*) to instead
>>>>>>>>> call *foo3*, which is defined in the
*refModule.  *So in summary,
>>>>>>>>> I have:
>>>>>>>>>
>>>>>>>>>    1. The original instruction call,
defined in the main function
>>>>>>>>>    of the oldModule, who is a calling
function to foo2, I'll name it
>>>>>>>>>    *oInst *(original Instruction)
>>>>>>>>>    2. The "new" instruction call,
defined in the main function of
>>>>>>>>>    the refModule, who is a calling function
to foo3, I'll name it
>>>>>>>>>    *nInst* (new Instruction)
>>>>>>>>>    3. The foo2 function definition, defined
in the oldModule,
>>>>>>>>>    I'll name it *oFunc *(original
Function)
>>>>>>>>>    4. The foo3 function definition, defined
in the refModule,
>>>>>>>>>    I'll name it *nFunc* (new Function)
>>>>>>>>>    5. I have the parameters (or arguments?)
of both functions,
>>>>>>>>>    both in the calling instruction and in
the function's definition, which
>>>>>>>>>    I'll refer to as *p(oInst)*,
*p(nInst)*, *p(oFunc)*, *p(nFunc)
>>>>>>>>>    *(the parameters of)
>>>>>>>>>    6. For testing purposes, both foo2 and
foo3 and defined
>>>>>>>>>    identical, same returning type,
parameter's type and even the same
>>>>>>>>>    variable's name in the IR.
>>>>>>>>>
>>>>>>>>> So after calling the
*llvm::LinkerlinkModules* function, I did:
>>>>>>>>>
>>>>>>>>> 1. First attempt:
>>>>>>>>>
>>>>>>>>>    1. llvm::CallInst *callOInst
>>>>>>>>>   
static_cast<llvm::CallInst*>(oInst);  // I cast the* oInst* to
>>>>>>>>>    a llvm::CallInst
>>>>>>>>>    2.
callOInst->setCalledFunction(nFunc); // now *oInst* should
>>>>>>>>>    call nFunc
>>>>>>>>>
>>>>>>>>> Error:
>>>>>>>>> Call parameter type does not match function
signature!
>>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>>> i32 %call1 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>>
>>>>>>>>> So even though the parameters are the same
type, and defined
>>>>>>>>> identically in both modules, the *p(oInst)*
apparently does not
>>>>>>>>> match the *p(nFunc)*.
>>>>>>>>>
>>>>>>>>> 2. Second attempt:
>>>>>>>>>
>>>>>>>>>    1. llvm::Instruction *nCloneInst =
nInst->clone(); //Clone of
>>>>>>>>>    the *nInst*, to avoid remove it from the
refModule
>>>>>>>>>    2. nCloneInst->insertAfter(oInst); //
I'll bring the nInst
>>>>>>>>>    because I know *p(nInst)* and *p(nFunc)*
match
>>>>>>>>>    3.
nCloneInst->mutateType(oInst->getType()); //Idk why I have
>>>>>>>>>    to this, but necessary for next line
>>>>>>>>>    4.
oInst->replaceAllUsesWith(nCloneInst);
>>>>>>>>>    5. oInst->dropAllReferences();
>>>>>>>>>    6. oInst->eraseFromParent();
>>>>>>>>>
>>>>>>>>> Error:
>>>>>>>>> Instruction does not dominate all uses!
>>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>>> %2 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>>
>>>>>>>>> Great, now the *p(nInst)* are still
referring to their definition
>>>>>>>>> in the refModule, so either I bring those
instructions too (which sounds
>>>>>>>>> really messy) or somehow I change the
*p(nInst)* to refer to the
>>>>>>>>> instructions in oldModule, which in my case
are actually defined the same
>>>>>>>>> (but apparently the references don't
change based on the name being the
>>>>>>>>> same in both modules).
>>>>>>>>>
>>>>>>>>> 3. Third attempt:
>>>>>>>>>
>>>>>>>>>    1. The same 1-4 steps as before, from
cloning instruction to
>>>>>>>>>    replaceAllUsesWith
>>>>>>>>>    2. llvm::CallInst *callNInst
>>>>>>>>>   
static_cast<llvm::CallInst*>(nCloneInst);
>>>>>>>>>    3. llvm::CallInst *callOInst
>>>>>>>>>   
static_cast<llvm::CallInst*>(oInst); // cast both *oInst* and
>>>>>>>>>    *nInst*
>>>>>>>>>    4. for (unsigned int i = 0; i <
>>>>>>>>>    callOInst->getNumArgOperands(); i++)
{
>>>>>>>>>   
callNInst->setArgOperand(i,callOInst->getArgOperand(i)); } //replace
>>>>>>>>>    *p(nInst)* with *p(oInst)*
>>>>>>>>>    5. The same 5-6 steps as before, drop
and erase
>>>>>>>>>
>>>>>>>>> Error:
>>>>>>>>> Call parameter type does not match function
signature!
>>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>>> i32  %2 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>>
>>>>>>>>> So back to the first problem, the *p(nInst)
*(now converted to
>>>>>>>>> *p(oInst)*) apparently does not match the
*p(nFunc)*.
>>>>>>>>>
>>>>>>>>> I also looked into the *CloneFunctionInto
*function, but I didn't
>>>>>>>>> understand the arguments of it, and
there's really no documentation or
>>>>>>>>> examples that I could find on the internet.
Specifically, I have troubles
>>>>>>>>> with *llvm::SmallVectorImpl<
llvm::ReturnInst *> &Returns *argument,
>>>>>>>>> I don't know how to initialize it, it
doesn't have a 0 argument constructor
>>>>>>>>> and if I try:
>>>>>>>>>
>>>>>>>>> llvm::SmallVectorImpl< llvm::ReturnInst
*> ReturnsArg >>>>>>>>> llvm::SmallVectorImpl<
llvm::ReturnInst *>(2); // Just as an example
>>>>>>>>>
>>>>>>>>> It says that constructor is protected. I
didn't want to go further
>>>>>>>>> since I'm clueless on how to properly
use this function, and I'm even not
>>>>>>>>> completely sure if it would fix all the
troubles that I've been having with
>>>>>>>>> the other three attempts.
>>>>>>>>>
>>>>>>>>> Btw, all these errors happen when I try to
run (through JIT) the
>>>>>>>>> module, a workaround that I know that I can
do for all my attempts is just
>>>>>>>>> to dump the module to a file, and then
reload it and execute it (I know it
>>>>>>>>> works since in both oldModule and refModule
I use the same IR variable's
>>>>>>>>> names) but I would like to do the work the
*right* way and not
>>>>>>>>> having to inefficiently dump a file just to
reload it again and get all the
>>>>>>>>> references right.
>>>>>>>>>
>>>>>>>>> Thanks for the help in advance, I'll be
really grateful for any
>>>>>>>>> advice or light in my situation.
>>>>>>>>>
>>>>>>>>> Regards,
>>>>>>>>> Daniel Moya
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> El mar., 28 de ago. de 2018 a la(s) 20:26,
Friedman, Eli (
>>>>>>>>> efriedma at codeaurora.org) escribió:
>>>>>>>>>
>>>>>>>>>> On 8/27/2018 10:37 AM, Daniel Moya via
llvm-dev wrote:
>>>>>>>>>> > Hello LLVM Developers,
>>>>>>>>>> >
>>>>>>>>>> > I'm trying to replace a
function defined in one module into
>>>>>>>>>> another
>>>>>>>>>> > module (different files). The
first issue I ran into was that
>>>>>>>>>> > llvm::Function does not have a
method "moveBefore" or
>>>>>>>>>> "moveAfter" as
>>>>>>>>>> > the llvm::BasicBlock or
llvm::Instruction do, so I figured I
>>>>>>>>>> would
>>>>>>>>>> > just move the BasicBlocks of the
replacing function into the
>>>>>>>>>> function
>>>>>>>>>> > that was being replaced, and then
eliminate the original
>>>>>>>>>> BasicBlocks.
>>>>>>>>>>
>>>>>>>>>> Cross-module operations are tricky in
general; I'd suggest using
>>>>>>>>>> the
>>>>>>>>>> Linker::linkModules API if possible.
>>>>>>>>>>
>>>>>>>>>> -Eli
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> Employee of Qualcomm Innovation Center,
Inc.
>>>>>>>>>> Qualcomm Innovation Center, Inc. is a
member of Code Aurora
>>>>>>>>>> Forum, a Linux Foundation Collaborative
Project
>>>>>>>>>>
>>>>>>>>>>
_______________________________________________
>>>>>>>>> LLVM Developers mailing list
>>>>>>>>> llvm-dev at lists.llvm.org
>>>>>>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>>>>>
>>>>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> llvm-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>
>>>>-------------- next part --------------
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Daniel Moya via llvm-dev

2018-Sep-06 11:07 UTC

head link

[llvm-dev] Replacing a function from one module into another one

Hi Philip,

The error happens when the program finishes and it automatically calls the
destructors, so it is not an error specifically inside my program. Here's
the full code:

#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/MCJIT.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <iostream>
#include <string.h>

const std::string originalFileName = "tracer.ll";
const std::string referenceFileName = "tracer_ref.ll";

void populateVMap(llvm::ValueToValueMapTy &VMap, llvm::Function *fOld,
llvm::Function *fNew) {
  llvm::Function::arg_iterator DestI = fOld->arg_begin();
  for (llvm::Function::const_arg_iterator J = fNew->arg_begin(); J
!fNew->arg_end();
       ++J) {
    DestI->setName(J->getName());
    VMap[&*J] = &*DestI++;
  }

void addFunction(llvm::Module *oMod, llvm::Module *nMod, std::string
nFName, std::string oFName) {
  llvm::Function *fNew = nMod->getFunction(nFName);
  llvm::Function *fOld = oMod->getFunction(oFName);

  fOld->dropAllReferences();
  fOld->deleteBody();

  llvm::ValueToValueMapTy VMap;
  populateVMap(VMap, fOld, fNew);
  bool ModuleArg = true;
  llvm::SmallVector<llvm::ReturnInst*, 8> Returns;
  llvm::CloneFunctionInto(fOld, fNew, VMap, ModuleArg, Returns);
  if (fNew->hasPersonalityFn())
     fOld->setPersonalityFn(llvm::MapValue(fNew->getPersonalityFn(),
VMap));
}

void replaceFunctions(std::string oldFuncName, std::string newFuncName) {
  llvm::SMDiagnostic origErr;
  llvm::LLVMContext origContext;
  std::unique_ptr<llvm::Module> origMod
(llvm::parseIRFile(originalFileName, origErr, origContext));
  llvm::Module *origMod_copy = origMod.get();
  llvm::SMDiagnostic refErr;
  llvm::LLVMContext refContext;
  std::unique_ptr<llvm::Module>
refMod(llvm::parseIRFile(referenceFileName,
refErr, refContext));
  llvm::Module *refMod_copy = refMod.get();

  addFunction(origMod_copy, refMod_copy, newFuncName, oldFuncName);
  printModule(origMod_copy);
  std::cout << "Finish\n"; // Make sure the program finished

}
int main() {
  std::string oldFuncName = "foo2";
  std::string newFuncName = "foo3";
  replaceFunctions(oldFuncName, newFuncName);
  return 0;
}


The complete error after printing the module (I know the error it's after
the program's execution because the "Finish" is printed before):

Finish
While deleting: i32 %
Use still stuck around after Def is destroyed:  %c = alloca i32, align 4
Use still stuck around after Def is destroyed:  %b.addr = alloca i32, align
4
Use still stuck around after Def is destroyed:  %a.addr = alloca i32, align
4
step3F: /home/moydan00/Clang/llvm-clang-6.0.0/lib/IR/Value.cpp:88:
llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when
a value
is destroyed!"' failed.

The beginning of the foo2 function in the tracer.ll:

define i32 @foo2(i32 %a, i32 %b) #0 {
entry:
  %a.addr = alloca i32, align 4
  %b.addr = alloca i32, align 4
  %c = alloca i32, align 4

The beginning of the foo3 function in the tracer_ref.ll:

define i32 @foo3(i32 %a, i32 %b) #0 {
entry:
  %a.addr = alloca i32, align 4
  %b.addr = alloca i32, align 4
  %c = alloca i32, align 4

I know it's a little bit confusing since both foo2 and foo3 are almost
identical, but from the error, I know that the instruction copied from foo3
to foo2 are still referring to the arguments in foo3. If any other
information is needed please tell me.

Regards,
Daniel Moya


El jue., 6 de sep. de 2018 a la(s) 11:36, Philip Pfaffe (
philip.pfaffe at gmail.com) escribió:
> Hi Daniel,
>
> when and where are you getting that error? Can you paste the full code?
>
> Cheers,
> Philip
>
> On Thu, Sep 6, 2018 at 2:11 AM Daniel Moya <danielmscr1994 at
gmail.com>
> wrote:
>
>> Hi Philip,
>>
>> Thanks for the reference, I was able to follow it and copy the code
that
>> I saw necessary, but I still have some issues (references are still not
>> updated). I created the function:
>>
>> void populateVMap(llvm::ValueToValueMapTy &VMap, llvm::Function
*fOld,
>> llvm::Function *fNew) {
>>   llvm::Function::arg_iterator DestI = fOld->arg_begin();
>>   for (llvm::Function::const_arg_iterator J = fNew->arg_begin(); J
!>> fNew->arg_end();
>>        ++J) {
>>     DestI->setName(J->getName());
>>     VMap[&*J] = &*DestI++;
>>   }
>> }
>>
>> The same as in *CloneModule*, then I have this code:
>>
>> llvm::Function *fNew = nMod->getFunction(nFName);
>> llvm::Function *fOld = oMod->getFunction(oFName);
>>
>> fOld->dropAllReferences();
>> fOld->deleteBody();
>>
>> llvm::ValueToValueMapTy VMap;
>> populateVMap(VMap, fOld, fNew);
>> bool ModuleArg = true;
>> llvm::SmallVector<llvm::ReturnInst*, 8> Returns;
>> llvm::CloneFunctionInto(fOld, fNew, VMap, ModuleArg, Returns);
>> if (fNew->hasPersonalityFn())
>>   
fOld->setPersonalityFn(llvm::MapValue(fNew->getPersonalityFn(), VMap));
>>
>> But after running the code, I still get the error: *Use still stuck
>> around after Def is destroyed*
>>
>> Which means that the instructions moved from *fNew* still refer to the
>> arguments of *fNew* instead of the "mapped" (supposedly) ones
in *fOld*.
>> I have some ideas of what could be going on:
>>
>>    1. I'm not populating correctly the VMap argument, although I
>>    wouldn't know how to do it differently since I literally copied
it from the
>>    *CloneModule*.
>>    2. I have to still add more instruction either before or after
>>    *CloneFunctionInto*, for example in *CloneModule* they call the
>>    function
[copyComdat](*http://llvm.org/doxygen/CloneModule_8cpp.html#a04b8f04da3f1b0bf1c9a2802f73e2d05
>>   
<http://llvm.org/doxygen/CloneModule_8cpp.html#a04b8f04da3f1b0bf1c9a2802f73e2d05>*),
>>    but I don't know if it's necessary (I guess no because
it's only defined in
>>    CloneModule.cpp), they also iterate over global alias and functions,
but
>>    since I'm only concerned in the arguments of one function, I
guess I don't
>>    have to worry about that.
>>    3. Perhaps what you mentioned before "Only operations across
>>    LLVMContexts are tricky" has something to do, because the
operation is
>>    between modules of different files, I'm guessing they have
different
>>    Contexts too, what could be done in this case?
>>
>> Finally, I also tried moving the BasicBlocks manually and got the same
>> error "Use still stuck..", and then tried
>> calling llvm::RemapFunction afterwards with the populated VMap, but
always
>> got the error:
>>
>> Assertion `(Flags & RF_IgnoreMissingLocals) &&
"Referenced value not in
>> value map!"' failed
>>
>> Which left me clueless since the mapping worked in the
>> *CloneFunctionInto* (the program executed fine, the error "Use
still
>> stuck" happened at the program's end) but not in this
*RemapFunction*.
>> Anyways, I believe *CloneFunctionInto* should do this remap work so I
>> shouldn't have to call *RemapFunction*. Any guideline would be
greatly
>> appreciated, it has been a long suffering.
>>
>> Regards,
>> Daniel Moya
>>
>>
>> El mié., 5 de sep. de 2018 a la(s) 11:15, Philip Pfaffe (
>> philip.pfaffe at gmail.com) escribió:
>>
>>> Hi Daniel,
>>>
>>> the implementation of [CloneModule](
>>> http://llvm.org/doxygen/CloneModule_8cpp_source.html) should be a
good
>>> example. Generally all you need to do in your case is map old
arguments to
>>> new arguments.
>>>
>>> Cheers,
>>> Philip
>>>
>>> On Tue, Sep 4, 2018 at 1:18 PM Daniel Moya <danielmscr1994 at
gmail.com>
>>> wrote:
>>>
>>>> Hi Philip,
>>>>
>>>> Thank you very much for your answer, the vector declaration
example
>>>> worked. I'm pretty sure the ValueToValueMapTy is the last
thing I need
>>>> because I even saw there is another function that could help me
llvm*:*
>>>> :RemapFunction
>>>>
<http://llvm.org/doxygen/namespacellvm.html#addf0183e92893bdbcde00fc9091dda93>;
>>>> but my problem is that I don't know how to populate the
ValueToValueMapTy
>>>> (VMap) and I couldn't find a single complete example on the
internet. To
>>>> begin with, as the name implies (and also from some errors that
I got) the
>>>> ValueToValueMapTy takes a std::pair<llvm::Value,
llvm::Value>, but what I
>>>> need is to map the arguments (llvm::Attribute) of both
functions (the first
>>>> argument of foo2 is equivalent to the first argument of foo3,
and so on),
>>>> however, apparently there's no transformation from a
llvm::Attribute to a
>>>> llvm::Value. I'm using the function getAttribute
>>>>
<http://llvm.org/doxygen/classllvm_1_1Function.html#ab2a5fc8baaee7e74dbe47d848508745a>
>>>>  (unsigned <http://llvm.org/doxygen/classunsigned.html>
i, StringRef
>>>> <http://llvm.org/doxygen/classllvm_1_1StringRef.html>
Kind
>>>>
<http://llvm.org/doxygen/ARMAsmParser_8cpp.html#a5ec5335889cd241b0ccfd4e4e58cf52e>
>>>> ) const
>>>>
<http://llvm.org/doxygen/AArch64PromoteConstant_8cpp.html#a90f8350fecae261c25be85d38b451bff>
to
>>>> get the attributes, but I don't even understand why is it
required to give
>>>> the StringRef
<http://llvm.org/doxygen/classllvm_1_1StringRef.html>
>>>> Kind
>>>>
<http://llvm.org/doxygen/ARMAsmParser_8cpp.html#a5ec5335889cd241b0ccfd4e4e58cf52e>
if
>>>> what I need is just the attribute of the function in the *i
*position.
>>>> I'm really thankful for the quick responses and for the
attention received.
>>>>
>>>> Regards,
>>>> Daniel Moya
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> El lun., 3 de sep. de 2018 a la(s) 18:42, Philip Pfaffe (
>>>> philip.pfaffe at gmail.com) escribió:
>>>>
>>>>> Hi Daniel,
>>>>>
>>>>> CloneFunctionInto wants to tell you about the new
ReturnInstructions
>>>>> it produced, you're expected to pass a vector for this
purpose. You're free
>>>>> to ignore these values, though, but you still have to pass
that
>>>>> vector:  SmallVector<ReturnInst*, 8> Returns;
>>>>>
>>>>> For the argument remapping, you're supposed to
pre-populate the VMap
>>>>> you pass with the appropriate argument-to-argument mapping.
>>>>>
>>>>> It's perfectly fine to use CloneFunctionInto across
modules, btw. Only
>>>>> operations across LLVMContexts are tricky.
>>>>>
>>>>> Cheers,
>>>>> Philip
>>>>>
>>>>> On Mon, Sep 3, 2018 at 6:31 PM Daniel Moya via llvm-dev
<
>>>>> llvm-dev at lists.llvm.org> wrote:
>>>>>
>>>>>> Thank you Ahmad,
>>>>>>
>>>>>> I figured out that, although the type of both p(oInst)
and p(nInst)
>>>>>> were the same, I had to:
>>>>>>
>>>>>> for (unsigned int i = 0; i <
callOInst->getNumArgOperands(); i++) {
>>>>>>
callOInst->getArgOperand(i)->mutateType(callNInst->getArgOperand(i)->getType());
>>>>>> }
>>>>>>
>>>>>> that solves the issue at the calling instruction in the
main
>>>>>> function, but now I see that *linkModules* does not
work for me
>>>>>> (it's a mess to bring all the other unnecessary
functions from the
>>>>>> reference module) so what I need is to directly move
one function from one
>>>>>> module to another one. I'm still facing the issue
with the *llvm::SmallVectorImpl<
>>>>>> llvm::ReturnInst *> &Returns *argument for the
*CloneFunctionInto, *can
>>>>>> anyone please give an example of use of that function?
I guess that's the
>>>>>> only way because otherwise if I move the blocks from
foo3 in the refModule
>>>>>> to the oldModule, the references of the moved block
still point to the
>>>>>> arguments of foo3 defined in the refModule, and I
don't know how to go
>>>>>> instruction by instruction in all the moved blocks and
correct the
>>>>>> reference to point to the arguments in the
oldModule's new function, this
>>>>>> also sounds very messy and complicated.
>>>>>>
>>>>>>
>>>>>> Regards,
>>>>>> Daniel Moya
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> El dom., 2 de sep. de 2018 a la(s) 23:18, Ahmad
Nouralizadeh Khorrami
>>>>>> (ahmad.llvm at gmail.com) escribió:
>>>>>>
>>>>>>> Hi Daniel,
>>>>>>> The answer was for your first thread. The benefits
are outlined in
>>>>>>> the repository, but your problem is still there.
I'm not sure. But this
>>>>>>> looks similar to my recent problem. I think that a
bitcast will solve the
>>>>>>> problem. The types after the linking process may
have different names but
>>>>>>> the same contents. The links to the answers are as
follows:
>>>>>>>
http://lists.llvm.org/pipermail/llvm-dev/2018-August/125413.html
>>>>>>>
>>>>>>>
https://stackoverflow.com/questions/51894129/convert-function-pointer-call-to-function-call-at-the-ir-level
>>>>>>> Regards.
>>>>>>>
>>>>>>> On Sun, 2 Sep 2018 at 23:30, Daniel Moya
<danielmscr1994 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi Ahmad,
>>>>>>>>
>>>>>>>> What does that tool does besides what LLVM
linker already does? I
>>>>>>>> don't think my problem is in linking both
modules, I think LLVM linker does
>>>>>>>> the job for me, the issue is when changing the
called function to call
>>>>>>>> another function (in the example previously
provided, to change it from
>>>>>>>> foo2 to foo3, and adjusting the function
parameter's references).
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Daniel Moya
>>>>>>>>
>>>>>>>> El dom., 2 de sep. de 2018 a la(s) 17:00, Ahmad
Nouralizadeh
>>>>>>>> Khorrami (ahmad.llvm at gmail.com) escribió:
>>>>>>>>
>>>>>>>>> Hi.
>>>>>>>>> Besides the LLVM linker, you can also use
this tool:
>>>>>>>>>
https://github.com/travitch/whole-program-llvm
>>>>>>>>> It links all the modules and produces a
single module containing
>>>>>>>>> every function.
>>>>>>>>> Regards.
>>>>>>>>>
>>>>>>>>> On Sun, 2 Sep 2018 at 16:57, Daniel Moya
via llvm-dev <
>>>>>>>>> llvm-dev at lists.llvm.org> wrote:
>>>>>>>>>
>>>>>>>>>> Hello and thanks for the answer,
>>>>>>>>>>
>>>>>>>>>> I'm still facing issues, I'll
do my best to explain my situation,
>>>>>>>>>> as I explained, I have two modules,
each one with its own main and
>>>>>>>>>> functions, I would like to replace in
the *oldModule* a function
>>>>>>>>>> call that is calling *foo2* (defined in
*oldModule*) to instead
>>>>>>>>>> call *foo3*, which is defined in the
*refModule.  *So in
>>>>>>>>>> summary, I have:
>>>>>>>>>>
>>>>>>>>>>    1. The original instruction call,
defined in the main
>>>>>>>>>>    function of the oldModule, who is a
calling function to foo2, I'll name it
>>>>>>>>>>    *oInst *(original Instruction)
>>>>>>>>>>    2. The "new" instruction
call, defined in the main function
>>>>>>>>>>    of the refModule, who is a calling
function to foo3, I'll name it
>>>>>>>>>>    *nInst* (new Instruction)
>>>>>>>>>>    3. The foo2 function definition,
defined in the oldModule,
>>>>>>>>>>    I'll name it *oFunc *(original
Function)
>>>>>>>>>>    4. The foo3 function definition,
defined in the refModule,
>>>>>>>>>>    I'll name it *nFunc* (new
Function)
>>>>>>>>>>    5. I have the parameters (or
arguments?) of both functions,
>>>>>>>>>>    both in the calling instruction and
in the function's definition, which
>>>>>>>>>>    I'll refer to as *p(oInst)*,
*p(nInst)*, *p(oFunc)*, *p(nFunc)
>>>>>>>>>>    *(the parameters of)
>>>>>>>>>>    6. For testing purposes, both foo2
and foo3 and defined
>>>>>>>>>>    identical, same returning type,
parameter's type and even the same
>>>>>>>>>>    variable's name in the IR.
>>>>>>>>>>
>>>>>>>>>> So after calling the
*llvm::LinkerlinkModules* function, I did:
>>>>>>>>>>
>>>>>>>>>> 1. First attempt:
>>>>>>>>>>
>>>>>>>>>>    1. llvm::CallInst *callOInst
>>>>>>>>>>   
static_cast<llvm::CallInst*>(oInst);  // I cast the* oInst*
>>>>>>>>>>    to a llvm::CallInst
>>>>>>>>>>    2.
callOInst->setCalledFunction(nFunc); // now *oInst* should
>>>>>>>>>>    call nFunc
>>>>>>>>>>
>>>>>>>>>> Error:
>>>>>>>>>> Call parameter type does not match
function signature!
>>>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>>>> i32 %call1 = call i32 @foo3(i32 %0, i32
%1)
>>>>>>>>>>
>>>>>>>>>> So even though the parameters are the
same type, and defined
>>>>>>>>>> identically in both modules, the
*p(oInst)* apparently does not
>>>>>>>>>> match the *p(nFunc)*.
>>>>>>>>>>
>>>>>>>>>> 2. Second attempt:
>>>>>>>>>>
>>>>>>>>>>    1. llvm::Instruction *nCloneInst =
nInst->clone(); //Clone of
>>>>>>>>>>    the *nInst*, to avoid remove it from
the refModule
>>>>>>>>>>    2.
nCloneInst->insertAfter(oInst); // I'll bring the nInst
>>>>>>>>>>    because I know *p(nInst)* and
*p(nFunc)* match
>>>>>>>>>>    3.
nCloneInst->mutateType(oInst->getType()); //Idk why I have
>>>>>>>>>>    to this, but necessary for next line
>>>>>>>>>>    4.
oInst->replaceAllUsesWith(nCloneInst);
>>>>>>>>>>    5. oInst->dropAllReferences();
>>>>>>>>>>    6. oInst->eraseFromParent();
>>>>>>>>>>
>>>>>>>>>> Error:
>>>>>>>>>> Instruction does not dominate all uses!
>>>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>>>> %2 = call i32 @foo3(i32 %0, i32 %1)
>>>>>>>>>>
>>>>>>>>>> Great, now the *p(nInst)* are still
referring to their
>>>>>>>>>> definition in the refModule, so either
I bring those instructions too
>>>>>>>>>> (which sounds really messy) or somehow
I change the *p(nInst)*
>>>>>>>>>> to refer to the instructions in
oldModule, which in my case are actually
>>>>>>>>>> defined the same (but apparently the
references don't change based on the
>>>>>>>>>> name being the same in both modules).
>>>>>>>>>>
>>>>>>>>>> 3. Third attempt:
>>>>>>>>>>
>>>>>>>>>>    1. The same 1-4 steps as before,
from cloning instruction to
>>>>>>>>>>    replaceAllUsesWith
>>>>>>>>>>    2. llvm::CallInst *callNInst
>>>>>>>>>>   
static_cast<llvm::CallInst*>(nCloneInst);
>>>>>>>>>>    3. llvm::CallInst *callOInst
>>>>>>>>>>   
static_cast<llvm::CallInst*>(oInst); // cast both *oInst* and
>>>>>>>>>>    *nInst*
>>>>>>>>>>    4. for (unsigned int i = 0; i <
>>>>>>>>>>    callOInst->getNumArgOperands();
i++) {
>>>>>>>>>>   
callNInst->setArgOperand(i,callOInst->getArgOperand(i)); } //replace
>>>>>>>>>>    *p(nInst)* with *p(oInst)*
>>>>>>>>>>    5. The same 5-6 steps as before,
drop and erase
>>>>>>>>>>
>>>>>>>>>> Error:
>>>>>>>>>> Call parameter type does not match
function signature!
>>>>>>>>>> %0 = load i32, i32* %a, align 4
>>>>>>>>>> i32  %2 = call i32 @foo3(i32 %0, i32
%1)
>>>>>>>>>>
>>>>>>>>>> So back to the first problem, the
*p(nInst) *(now converted to
>>>>>>>>>> *p(oInst)*) apparently does not match
the *p(nFunc)*.
>>>>>>>>>>
>>>>>>>>>> I also looked into the
*CloneFunctionInto *function, but I
>>>>>>>>>> didn't understand the arguments of
it, and there's really no documentation
>>>>>>>>>> or examples that I could find on the
internet. Specifically, I have
>>>>>>>>>> troubles with
*llvm::SmallVectorImpl< llvm::ReturnInst *>
>>>>>>>>>> &Returns *argument, I don't
know how to initialize it, it
>>>>>>>>>> doesn't have a 0 argument
constructor and if I try:
>>>>>>>>>>
>>>>>>>>>> llvm::SmallVectorImpl<
llvm::ReturnInst *> ReturnsArg >>>>>>>>>>
llvm::SmallVectorImpl< llvm::ReturnInst *>(2); // Just as an example
>>>>>>>>>>
>>>>>>>>>> It says that constructor is protected.
I didn't want to go
>>>>>>>>>> further since I'm clueless on how
to properly use this function, and I'm
>>>>>>>>>> even not completely sure if it would
fix all the troubles that I've been
>>>>>>>>>> having with the other three attempts.
>>>>>>>>>>
>>>>>>>>>> Btw, all these errors happen when I try
to run (through JIT) the
>>>>>>>>>> module, a workaround that I know that I
can do for all my attempts is just
>>>>>>>>>> to dump the module to a file, and then
reload it and execute it (I know it
>>>>>>>>>> works since in both oldModule and
refModule I use the same IR variable's
>>>>>>>>>> names) but I would like to do the work
the *right* way and not
>>>>>>>>>> having to inefficiently dump a file
just to reload it again and get all the
>>>>>>>>>> references right.
>>>>>>>>>>
>>>>>>>>>> Thanks for the help in advance,
I'll be really grateful for any
>>>>>>>>>> advice or light in my situation.
>>>>>>>>>>
>>>>>>>>>> Regards,
>>>>>>>>>> Daniel Moya
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> El mar., 28 de ago. de 2018 a la(s)
20:26, Friedman, Eli (
>>>>>>>>>> efriedma at codeaurora.org) escribió:
>>>>>>>>>>
>>>>>>>>>>> On 8/27/2018 10:37 AM, Daniel Moya
via llvm-dev wrote:
>>>>>>>>>>> > Hello LLVM Developers,
>>>>>>>>>>> >
>>>>>>>>>>> > I'm trying to replace a
function defined in one module into
>>>>>>>>>>> another
>>>>>>>>>>> > module (different files). The
first issue I ran into was that
>>>>>>>>>>> > llvm::Function does not have a
method "moveBefore" or
>>>>>>>>>>> "moveAfter" as
>>>>>>>>>>> > the llvm::BasicBlock or
llvm::Instruction do, so I figured I
>>>>>>>>>>> would
>>>>>>>>>>> > just move the BasicBlocks of
the replacing function into the
>>>>>>>>>>> function
>>>>>>>>>>> > that was being replaced, and
then eliminate the original
>>>>>>>>>>> BasicBlocks.
>>>>>>>>>>>
>>>>>>>>>>> Cross-module operations are tricky
in general; I'd suggest using
>>>>>>>>>>> the
>>>>>>>>>>> Linker::linkModules API if
possible.
>>>>>>>>>>>
>>>>>>>>>>> -Eli
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Employee of Qualcomm Innovation
Center, Inc.
>>>>>>>>>>> Qualcomm Innovation Center, Inc. is
a member of Code Aurora
>>>>>>>>>>> Forum, a Linux Foundation
Collaborative Project
>>>>>>>>>>>
>>>>>>>>>>>
_______________________________________________
>>>>>>>>>> LLVM Developers mailing list
>>>>>>>>>> llvm-dev at lists.llvm.org
>>>>>>>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>>>>>>
>>>>>>>>>
_______________________________________________
>>>>>> LLVM Developers mailing list
>>>>>> llvm-dev at lists.llvm.org
>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>>
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llvm dev - Sep 2018 - Replacing a function from one module into another one

[llvm-dev] Replacing a function from one module into another one

[llvm-dev] Replacing a function from one module into another one

[llvm-dev] Replacing a function from one module into another one