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Gabi

2010-Mar-23 11:04 UTC

[LLVMdev] How to avoid memory leaks

Hi
I get huge memory leaks using LLVM IRBuilder (trunk version)

Basically I recreate a function over and over again, and pretty sure
that my code doesn't cause the leak
while(true)
{
 Function *fn = module->getFunction(name);
    if (fn)
       fn->eraseFromParent();

    fn =  cast<Function>(module->getOrInsertFunction(name, fnType));
    fillFunction(fn); //Fill function with some blocks and instructions..
}

Is there any documentation guideline on how to manage memory with
LLVM? . I am kind of lost here. I tried anything I could but it seems
the leaks won't go away

Valgrind gives me lots of ..

110,560 bytes in 1,382 blocks are possibly lost in loss record 176 of 181
==17474==    at 0x4C2596C: operator new(unsigned long) (vg_replace_malloc.c:220)
==17474==    by 0x90A922: llvm::User::operator new(unsigned long,
unsigned int) (in /home/gabi/vgen/Debug/vgen)
==17474==    by 0x88A5B6: llvm::ConstantFP::get(llvm::LLVMContext&,
llvm::APFloat const&) (in /home/gabi/vgen/Debug/vgen)
==17474==    by 0x925E17: llvm::ConstantFoldBinaryInstruction(unsigned
int, llvm::Constant*, llvm::Constant*) (in /home/gabi/vgen/Debug/vgen)
==17474==    by 0x889587: llvm::ConstantExpr::getTy(llvm::Type const*,
unsigned int, llvm::Constant*, llvm::Constant*, unsigned int) (in
/home/gabi/vgen/Debug/vgen)
==17474==    by 0x423030:
llvm::ConstantFolder::CreateFSub(llvm::Constant*, llvm::Constant*)
const (ConstantFolder.h:58)
==17474==    by 0x423F7E: llvm::IRBuilder<true, llvm::ConstantFolder,
llvm::IRBuilderDefaultInserter<true> >::CreateFSub(llvm::Value*,
llvm::Value*, llvm::Twine const&)

and also...
==17474== 2,880 bytes in 40 blocks are possibly lost in loss record 155 of 181
==17474==    at 0x4C2596C: operator new(unsigned long) (vg_replace_malloc.c:220)
==17474==    by 0x90A922: llvm::User::operator new(unsigned long,
unsigned int) (in /home/gabi/vgen/Debug/vgen)
==17474==    by 0x88423B: llvm::ConstantInt::get(llvm::LLVMContext&,
llvm::APInt const&) (in /home/gabi/vgen/Debug/vgen)
==17474==    by 0x8843B4: llvm::ConstantInt::get(llvm::IntegerType
const*, unsigned long, bool) (in /home/gabi/vgen/Debug/vgen)

-- 
Regards,
Gabi

http://bugspy.net

Reid Kleckner

2010-Mar-23 14:49 UTC

head link

[LLVMdev] How to avoid memory leaks

On Tue, Mar 23, 2010 at 7:04 AM, Gabi <bugspynet at gmail.com>
wrote:> Hi
> I get huge memory leaks using LLVM IRBuilder (trunk version)
>
> Basically I recreate a function over and over again, and pretty sure
> that my code doesn't cause the leak
> while(true)
> {
>  Function *fn = module->getFunction(name);
>    if (fn)
>       fn->eraseFromParent();
Err, shouldn't you delete fn here?  I'm pretty sure that this just
removes the function from the module.
>    fn =  cast<Function>(module->getOrInsertFunction(name,
fnType));
>    fillFunction(fn); //Fill function with some blocks and instructions..
> }
Reid

Anders Johnsen

2010-Mar-23 14:53 UTC

head link

[LLVMdev] How to avoid memory leaks

I think you need to call "llvm::Function::deleteBody() first"

On Tue, Mar 23, 2010 at 15:49, Reid Kleckner <rnk at mit.edu>
wrote:> On Tue, Mar 23, 2010 at 7:04 AM, Gabi <bugspynet at gmail.com> wrote:
>> Hi
>> I get huge memory leaks using LLVM IRBuilder (trunk version)
>>
>> Basically I recreate a function over and over again, and pretty sure
>> that my code doesn't cause the leak
>> while(true)
>> {
>>  Function *fn = module->getFunction(name);
>>    if (fn)
>>       fn->eraseFromParent();
>
> Err, shouldn't you delete fn here?  I'm pretty sure that this just
> removes the function from the module.
Doxygen says that:
"eraseFromParent - This method unlinks 'this' from the containing
module and deletes it."

so it should be fine just calling erase.
>
>>    fn =  cast<Function>(module->getOrInsertFunction(name,
fnType));
>>    fillFunction(fn); //Fill function with some blocks and
instructions..
>> }
>
> Reid
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
- Anders

Jeffrey Yasskin

2010-Mar-23 16:08 UTC

head link

[LLVMdev] How to avoid memory leaks

I fixed a leak that manifests like this in
http://llvm.org/viewvc/llvm-project?rev=99160&view=rev. Are you synced
past there? That leak would only show up in this way if you create at
least 1,382 distinct ConstantFPs, which leaks me to believe you didn't
show us all of your code. When diagnosing a leak, it's important to
have all of the context. You should also run valgrind with
--num-callers=50 to get more of the stack trace. When it cuts off
inside of LLVM, that doesn't help in reproducing the problem.

On Tue, Mar 23, 2010 at 4:04 AM, Gabi <bugspynet at gmail.com>
wrote:> Hi
> I get huge memory leaks using LLVM IRBuilder (trunk version)
>
> Basically I recreate a function over and over again, and pretty sure
> that my code doesn't cause the leak
> while(true)
> {
>  Function *fn = module->getFunction(name);
>    if (fn)
>       fn->eraseFromParent();
>
>    fn =  cast<Function>(module->getOrInsertFunction(name,
fnType));
>    fillFunction(fn); //Fill function with some blocks and instructions..
> }
>
> Is there any documentation guideline on how to manage memory with
> LLVM? . I am kind of lost here. I tried anything I could but it seems
> the leaks won't go away
>
> Valgrind gives me lots of ..
>
> 110,560 bytes in 1,382 blocks are possibly lost in loss record 176 of 181
> ==17474==    at 0x4C2596C: operator new(unsigned long)
(vg_replace_malloc.c:220)
> ==17474==    by 0x90A922: llvm::User::operator new(unsigned long,
> unsigned int) (in /home/gabi/vgen/Debug/vgen)
> ==17474==    by 0x88A5B6: llvm::ConstantFP::get(llvm::LLVMContext&,
> llvm::APFloat const&) (in /home/gabi/vgen/Debug/vgen)
> ==17474==    by 0x925E17: llvm::ConstantFoldBinaryInstruction(unsigned
> int, llvm::Constant*, llvm::Constant*) (in /home/gabi/vgen/Debug/vgen)
> ==17474==    by 0x889587: llvm::ConstantExpr::getTy(llvm::Type const*,
> unsigned int, llvm::Constant*, llvm::Constant*, unsigned int) (in
> /home/gabi/vgen/Debug/vgen)
> ==17474==    by 0x423030:
> llvm::ConstantFolder::CreateFSub(llvm::Constant*, llvm::Constant*)
> const (ConstantFolder.h:58)
> ==17474==    by 0x423F7E: llvm::IRBuilder<true, llvm::ConstantFolder,
> llvm::IRBuilderDefaultInserter<true> >::CreateFSub(llvm::Value*,
> llvm::Value*, llvm::Twine const&)
>
> and also...
> ==17474== 2,880 bytes in 40 blocks are possibly lost in loss record 155 of
181
> ==17474==    at 0x4C2596C: operator new(unsigned long)
(vg_replace_malloc.c:220)
> ==17474==    by 0x90A922: llvm::User::operator new(unsigned long,
> unsigned int) (in /home/gabi/vgen/Debug/vgen)
> ==17474==    by 0x88423B: llvm::ConstantInt::get(llvm::LLVMContext&,
> llvm::APInt const&) (in /home/gabi/vgen/Debug/vgen)
> ==17474==    by 0x8843B4: llvm::ConstantInt::get(llvm::IntegerType
> const*, unsigned long, bool) (in /home/gabi/vgen/Debug/vgen)
>
> --
> Regards,
> Gabi
>
> http://bugspy.net
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>

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