Shen Liu
2015-Jul-17 18:06 UTC
[LLVMdev] How can i differentiate pointer type int 32* from int 32** ?
John, thanks for you answer! But as far as I know LLVM doesn't provide any interface for finding the pointee of a pointer directly, so i have to process a multi-level pointer i need to write my own function to check pointers level by level, is that right? On Fri, Jul 17, 2015 at 1:47 PM, John Criswell <jtcriswel at gmail.com> wrote:> On 7/17/15 12:38 PM, Shen Liu wrote: > > Hi all, as a LLVM beginner I would like to know how can i check the > pointer types with different levels like int 32* and int 32**, int 32***? > > By using value->getType()->isPointerTy() i can just know they are > pointers. But the dump results clearly show they are different. Is there a > good way to calculate their actual point to levels? Thanks! > > > You will need to use dyn_cast<PointerType> to cast the Type * into a > PointerType *. Once you do that, you can find the Type * that the > PointerType points to. > > Regards, > > John Criswell > > > > Best regards, > > Shen > > > _______________________________________________ > LLVM Developers mailing listLLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.eduhttp://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > > > > -- > John Criswell > Assistant Professor > Department of Computer Science, University of Rochesterhttp://www.cs.rochester.edu/u/criswell > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150717/ba304d4f/attachment.html>
John Criswell
2015-Jul-17 18:22 UTC
[LLVMdev] How can i differentiate pointer type int 32* from int 32** ?
On 7/17/15 1:06 PM, Shen Liu wrote:> John, thanks for you answer! But as far as I know LLVM doesn't > provide any interface for finding the pointee of a pointer directly, > so i have to process a multi-level pointer i need to write my own > function to check pointers level by level, is that right?I'm not sure what you're trying to do. If you're trying to determine the LLVM pointer type and the LLVM type to which it points, what I've said will work. If you're trying to do something more complicated, then you need to explain more clearly what you want to do. I think it would also help if you "jumped up a level" and explained what your end goal is so that the community can give you better advice. Based on your previous emails, it seems like you're asking very specific questions instead of asking how to best achieve your overall goal. Regards, John Criswell> > On Fri, Jul 17, 2015 at 1:47 PM, John Criswell <jtcriswel at gmail.com > <mailto:jtcriswel at gmail.com>> wrote: > > On 7/17/15 12:38 PM, Shen Liu wrote: >> Hi all, as a LLVM beginner I would like to know how can i check >> the pointer types with different levels like int 32* and int >> 32**, int 32***? >> >> By using value->getType()->isPointerTy() i can just know they are >> pointers. But the dump results clearly show they are different. >> Is there a good way to calculate their actual point to levels? >> Thanks! > > You will need to use dyn_cast<PointerType> to cast the Type * into > a PointerType *. Once you do that, you can find the Type * that > the PointerType points to. > > Regards, > > John Criswell > >> >> >> Best regards, >> >> Shen >> >> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu <mailto:LLVMdev at cs.uiuc.edu> http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > > > -- > John Criswell > Assistant Professor > Department of Computer Science, University of Rochester > http://www.cs.rochester.edu/u/criswell > >-- John Criswell Assistant Professor Department of Computer Science, University of Rochester http://www.cs.rochester.edu/u/criswell -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150717/a6112e43/attachment.html>
Shen Liu
2015-Jul-18 01:32 UTC
[LLVMdev] How can i differentiate pointer type int 32* from int 32** ?
John, thanks for your helpful advice. My ultimate goal is to construct a full instruction-level program dependence graph for a given IR file. The hard point is how to establish the correct data dependence edges when some function arguments are multi-level pointers. To solve this problem I hope to check the point-to level for each pointer variable. I think the data dependence through pointers can be described more accurately in this way. Unfortunately i didn't find any available interface to finish this job, so i guess i have to write it by myself. Best regards, Shen On Fri, Jul 17, 2015 at 2:22 PM, John Criswell <jtcriswel at gmail.com> wrote:> On 7/17/15 1:06 PM, Shen Liu wrote: > > John, thanks for you answer! But as far as I know LLVM doesn't provide > any interface for finding the pointee of a pointer directly, so i have to > process a multi-level pointer i need to write my own function to check > pointers level by level, is that right? > > > I'm not sure what you're trying to do. If you're trying to determine the > LLVM pointer type and the LLVM type to which it points, what I've said will > work. > > If you're trying to do something more complicated, then you need to > explain more clearly what you want to do. I think it would also help if > you "jumped up a level" and explained what your end goal is so that the > community can give you better advice. Based on your previous emails, it > seems like you're asking very specific questions instead of asking how to > best achieve your overall goal. > > Regards, > > John Criswell > > > > On Fri, Jul 17, 2015 at 1:47 PM, John Criswell <jtcriswel at gmail.com> > wrote: > >> On 7/17/15 12:38 PM, Shen Liu wrote: >> >> Hi all, as a LLVM beginner I would like to know how can i check the >> pointer types with different levels like int 32* and int 32**, int 32***? >> >> By using value->getType()->isPointerTy() i can just know they are >> pointers. But the dump results clearly show they are different. Is there a >> good way to calculate their actual point to levels? Thanks! >> >> >> You will need to use dyn_cast<PointerType> to cast the Type * into a >> PointerType *. Once you do that, you can find the Type * that the >> PointerType points to. >> >> Regards, >> >> John Criswell >> >> >> >> Best regards, >> >> Shen >> >> >> _______________________________________________ >> LLVM Developers mailing listLLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.eduhttp://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> >> >> >> -- >> John Criswell >> Assistant Professor >> Department of Computer Science, University of Rochesterhttp://www.cs.rochester.edu/u/criswell >> >> > > > -- > John Criswell > Assistant Professor > Department of Computer Science, University of Rochesterhttp://www.cs.rochester.edu/u/criswell > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150717/06d47dfc/attachment.html>