[llvm-dev] Replacing a function from one module into another one
Daniel Moya via llvm-dev
llvm-dev at lists.llvm.org
Tue Sep 18 14:56:44 PDT 2018
Hello LLVM Developers,
I hope not to bother, I would like to know if there's any new information
related to the status of this query, whether it's already being analyzed or
if there's an idea of what could be wrong with my program. I know I can
count on the workaround that I mentioned for this matter, but I would like
to know your thoughts on the problem so far, for documentation issues.
Thanks again for all the help that has been given.
Regards,
Daniel Moya
El jue., 6 de sep. de 2018 a la(s) 14:33, Daniel Moya (
danielmscr1994 at gmail.com) escribió:
> No, the source function (foo3 defined in tracer_ref.ll in this case) is
> only referencing, inside its function body, to the arguments that it takes.
> This could be a minimum-version of the tracer_ref.ll file:
>
> ; ModuleID = 'tracer_ref.c'
> source_filename = "tracer_ref.c"
> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> target triple = "x86_64-unknown-linux-gnu"
>
> @.str = private unnamed_addr constant [11 x i8] c"C1 is: %d\0A\00", align 1
> @.str.1 = private unnamed_addr constant [11 x i8] c"C2 is: %d\0A\00",
> align 1
>
> ; Function Attrs: noinline nounwind optnone uwtable
> define i32 @main() #0 {
> entry:
> %a = alloca i32, align 4
> %b = alloca i32, align 4
> store i32 7, i32* %a, align 4
> store i32 5, i32* %b, align 4
> %0 = load i32, i32* %a, align 4
> %1 = load i32, i32* %b, align 4
> %call1 = call i32 @foo3(i32 %0, i32 %1)
> store i32 %call1, i32* %c2, align 4
> %3 = load i32, i32* %c2, align 4
> %call3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x
> i8], [11 x i8]* @.str.1, i32 0, i32 0), i32 %3)
> ret i32 0
> }
>
> ; Function Attrs: noinline nounwind optnone uwtable
> 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
> store i32 %a, i32* %a.addr, align 4
> store i32 %b, i32* %b.addr, align 4
> %0 = load i32, i32* %a.addr, align 4
> %1 = load i32, i32* %b.addr, align 4
> %mul = mul nsw i32 %0, %1
> store i32 %mul, i32* %c, align 4
> %2 = load i32, i32* %c, align 4
> %3 = load i32, i32* %b.addr, align 4
> %mul1 = mul nsw i32 %2, %3
> store i32 %mul1, i32* %c, align 4
> %4 = load i32, i32* %c, align 4
> %5 = load i32, i32* %a.addr, align 4
> %mul2 = mul nsw i32 %4, %5
> store i32 %mul2, i32* %c, align 4
> %6 = load i32, i32* %c, align 4
> ret i32 %6
> }
>
> attributes #0 = { noinline nounwind optnone uwtable
> "correctly-rounded-divide-sqrt-fp-math"="false"
> "disable-tail-calls"="false" "less-precise-fpmad"="false"
> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
> "no-infs-fp-math"="false" "no-jump-tables"="false"
> "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false"
> "no-trapping-math"="false" "stack-protector-buffer-size"="8"
> "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
> "unsafe-fp-math"="false" "use-soft-float"="false" }
> attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false"
> "disable-tail-calls"="false" "less-precise-fpmad"="false"
> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
> "no-infs-fp-math"="false" "no-nans-fp-math"="false"
> "no-signed-zeros-fp-math"="false" "no-trapping-math"="false"
> "stack-protector-buffer-size"="8" "target-cpu"="x86-64"
> "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false"
> "use-soft-float"="false" }
>
> !llvm.module.flags = !{!0}
> !llvm.ident = !{!1}
>
> The error happens with the first three instructions of *foo3*, and the
> first two are a direct reference to the arguments of *foo3* (I don't know
> why the error message includes the third instruction). There are *no*
> global variables in both module files. Thanks for the quick responses, it
> really helps.
>
> Regards,
> Daniel Moya
>
> El jue., 6 de sep. de 2018 a la(s) 14:08, Philip Pfaffe (
> philip.pfaffe at gmail.com) escribió:
>
>> Is the source function referencing global variables? You'll have to move
>> those too.
>>
>> Cheers,
>> Philip
>>
>> On Thu, Sep 6, 2018 at 1:07 PM Daniel Moya <danielmscr1994 at gmail.com>
>> wrote:
>>
>>> 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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