[LLVMdev] LLVM problem, please do not ignore

[Duncan Sands]

Hi Arshak, build LLVM with assertions on.  Then you will get helpful messages
like "Destroying a value while uses still around!" and so on.  You need to use
replaceAllUsesWith to replace all uses of the add with something else (eg an
undef value of the same type) before you delete it.

Ciao, Duncan.

On 11/03/11 11:55, Arshak Nazaryan wrote:
> Dear sir or madam,
>
> I am a 4-th year student at Yerevan State University, Armenia; and I am studying
> LLVM in order to write my Bachelor thesis.
> I am trying to write an llvm pass that just removes all "Add" commands and gives
> some statstics.
> Nevertheless, I get this segmentation fault:
>
> ................some rows about functions, that are not changed by my pass. The
> errors occurs after it has modified a "@_Z3addii" function.
> store i32 %b.0, i32* %4  and the type is ddddbbm 28
>    %5 = load i32* %a_addr, align 4  and the type is ddddbbm 27
>    %6 = load i32* %b_addr, align 4  and the type is ddddbbm 27
>    %7 = add nsw i32 %5, %6  and the type is ddddbbm 8
>    store i32 %7, i32* %0, align 4  and the type is ddddbbm 28
>    %7 = add nsw i32 %5, %6   is erased, ba!
>    %7 = load i32* %0, align 4  and the type is ddddbbm 27
>    store i32 %7, i32* %retval, align 4  and the type is ddddbbm 28
>    br label %return  and the type is ddddbbm 2
>    ret i32 %retval1  and the type is ddddbbm 1
> 0  opt             0x00000000008ed93f
> 1  opt             0x00000000008edcea
> 2  libpthread.so.0 0x00007f9ba1183c60
> 3  opt             0x00000000004b3615 llvm::PATypeHolder::get() const + 21
> 4  opt             0x00000000008a4f11
> 5  opt             0x00000000008a9404
> 6  opt             0x0000000000882557
> llvm::FPPassManager::runOnFunction(llvm::Function&) + 551
> 7  opt             0x00000000008825db
> llvm::FPPassManager::runOnModule(llvm::Module&) + 75
> 8  opt             0x0000000000882197
> llvm::MPPassManager::runOnModule(llvm::Module&) + 503
> 9  opt             0x0000000000882299 llvm::PassManagerImpl::run(llvm::Module&)
> + 137
> 10 opt             0x00000000004ac451 main + 4881
> 11 libc.so.6       0x00007f9ba0459eff __libc_start_main + 255
> 12 opt             0x000000000049f5f9
> Stack dump:
> 0.Program arguments: opt hello.bc -load
> ../llvm/llvm-2.9/plugin/BasicBlockStats.so -basic-block-stats -stats -o newhello.bc
> 1.Running pass 'Function Pass Manager' on module 'hello.bc'.
> 2.Running pass 'Module Verifier' on function '@_Z3addii'
> Segmentation fault
>
> Please find the source of my pass attached.
> Hope to get a reply soon.
>
> Regards,
> Arshak Nazaryan
>
>
>
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