[LLVMdev] struct type parament

[Haopeng Liu]

I tried to compare two types. Because of renaming, the comparison result 
is not as expected. How to deal with renaming while comparing types?

Best,
Haopeng

On 6/2/15 4:09 PM, Mehdi Amini wrote:
> Hi Haopeng,
>
> One more element, I just noticed you are using LTO, I am not sure how it is implemented but my guess is that there is a shared LLVMContext. If multiple files include this structure declaration, I wouldn’t be surprised if it trigger creating the type over and over in the IR.
>
> Why is it a problem for you by the way? Does the compilation fails in some way?
>
> —
> Mehdi
>
>> On Jun 2, 2015, at 1:31 PM, Haopeng Liu <hyliuhp at gmail.com> wrote:
>>
>> Hi Mehdi,
>>
>> Thanks for your reply.
>>
>> It seems caused by random rename because I saw %struct.StructTyName.692.475*, which might be twice renaming.
>>
>> Does this collision occur because this type is declared more than once?
>>
>> I encountered this problem when used clang to compile transmission 1.42 (http://download.transmissionbt.com/files/) with configuration: "./configure --disable-gtk". Then in ./third-party/libevent/event.o.ll, you can see the function "event_base_get_method" is an example.
>>
>> Best,
>> Haopeng
>>
>> On 6/2/15 1:48 PM, Mehdi Amini wrote:
>>> Hi,
>>>
>>> I think this is when a collision is found on the name.
>>> I would be interesting to have the full test, it might be that the API is used in a way such that type is constantly re-created even if it already exists, which might be inefficient.
>>>
>>> See in lib/IR/Type.cpp, StructType::setName(StringRef Name):
>>>
>>> ...
>>>    // While we have a name collision, try a random rename.
>>>    if (Entry->getValue()) {
>>>      SmallString<64> TempStr(Name);
>>>      TempStr.push_back('.');
>>>      raw_svector_ostream TmpStream(TempStr);
>>>      unsigned NameSize = Name.size();
>>>          do {
>>>        TempStr.resize(NameSize + 1);
>>>        TmpStream.resync();
>>>        TmpStream << getContext().pImpl->NamedStructTypesUniqueID++;
>>>               Entry = &getContext().pImpl->
>>>                   NamedStructTypes.GetOrCreateValue(TmpStream.str());
>>>      } while (Entry->getValue());
>>>    }
>>>
>>>
>>> —
>>> Mehdi
>>>
>>>> On Jun 2, 2015, at 11:23 AM, Haopeng Liu <hyliuhp at gmail.com> wrote:
>>>>
>>>> Hi All,
>>>>
>>>> I generated the following code with "clang -flto" command.
>>>>
>>>> void test(struct StruTyName *a) {
>>>>     ...
>>>> }
>>>>
>>>> Then the type of test function is "void (%struct.StruTyName.100*)" by calling function::getFunctionType API.
>>>>
>>>> What's the meaning of number 100?
>>>>
>>>> Best,
>>>> Haopeng
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