CODEWITHSUNDEEP
llvminlinellvm-clang
piXel_pRo
piXel_pRo

Reputation: 159

Clang does not inline calls having pointer casts (indirect function calls)

I was trying to inline functions in llvm using this command:

opt -inline -inline-threshold=1000000 a.bc -o a.inline.bc

The (indirect) function calls involving pointer casts were not been able to inline. For eg.

%call4 = call i32 (...)* bitcast (i32 (%struct.token_type*)* @print_token to i32 (...)*)(%struct.token_type* %5)

But the functions calls like the one below are being inlined:

%call49 = call i32 @special(i32 %43)

Can I inline all the function calls irrespective of the fact whether they are direct or indirect??

Thanks!

Upvotes: 0

Views: 310

Answers (1)

Grady Player
Grady Player

Reputation: 14549

You can't inline something if you don't know what it is, and a function pointer that is assigned at run time can not be know at any point during the build process... If it is defined in such a way as to be reassign-able then it couldn't be possibly inlined... Calling code could be inlined, but calls to function pointers can't be....

It is possible that there are some scenarios that could possibly be inlined that llvm is overly cautious about, but that would probably be an issue for the llvm dev list...

And you haven't given a concrete example to look at for someone wiser than me to look at, to know if it should be possible to inline in your scenario.

Upvotes: 2

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