search for: variablesizedstructs

...known. These "late bound >> constants" could then be used to implement "sizeof(type)" and other >> constants whose value is different on different targets. >> > > LLVM already does this. > > http://www.nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt > > — Gordon > Is there a similar technique that would allow calculation of the alignment? (which is also required by the DWARF derived-type descriptor.) -- Talin

...gt; code using GEP's without worrying about how a given target actually > lays out structures. It isn't target-independent in the sense that > the actual computed offset in bytes isn't the same for every target. > See also > http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt > . > > -Eli > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20111208/4aefbbeb/attachment.html>

...ld maybe add this example to the getelementptr >> documentation. > > This isn't really appropriate for the reference manual, but I added it to > the "Source Language Implementation Notes" of my web page here: > > http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt > > Hope this helps! Bingo, it does help! Thanks Chris! However, I'm with Aaron on where this belongs, your link above really should be integrated into or at least an addendum to the IR Language Reference, http://llvm.cs.uiuc.edu/docs/LangRef.html unless you're keeping it o...

I'm implementing c style "sizeof()", and I did as http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt illuarstrated, and it works find, here's an example of my implementation: auto *p = builder.CreateGEP(structTy, llvm::ConstantPointerNull::get(pointerTy), constint1); auto *size = builder.CreatePtrToInt(p, llvm::IntegerType::get...

Hello! You can do this: http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt On Fri, May 7, 2010 at 8:26 PM, Gang.Yao <ttoole9 at gmail.com> wrote: > Hi: > > just like the c function sizeof(). I would avoid the usage of the c > function call, and expect something like llvm > intrinsic or some class providing this functionality. > > Does some...

On Thu, Dec 8, 2011 at 2:37 PM, Ryan Taylor <ryta1203 at gmail.com> wrote: > Thanks. > > So basically then this operation is not target-independent like the docs > suggest? > > > On Thu, Dec 8, 2011 at 1:23 PM, Eli Friedman <eli.friedman at gmail.com>wrote: > >> On Thu, Dec 8, 2011 at 11:49 AM, Ryan Taylor <ryta1203 at gmail.com> wrote: >>

...a frontend can generate code using GEP's without worrying about how a given target actually lays out structures. It isn't target-independent in the sense that the actual computed offset in bytes isn't the same for every target. See also http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt . -Eli

...EP's without worrying about how a given target actually >> lays out structures.  It isn't target-independent in the sense that >> the actual computed offset in bytes isn't the same for every target. >> See also >> http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt >> . >> >> -Eli > >

...e this: ... > Chris you should maybe add this example to the getelementptr documentation. This isn't really appropriate for the reference manual, but I added it to the "Source Language Implementation Notes" of my web page here: http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt Hope this helps! -Chris -- http://nondot.org/sabre/ http://llvm.cs.uiuc.edu/

...; until the compilation target is fully known. These "late bound > constants" could then be used to implement "sizeof(type)" and other > constants whose value is different on different targets. LLVM already does this. http://www.nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt — Gordon

On May 22, 2008, at 6:40 PM, Talin wrote: >> LLVM already does this. >> >> http://www.nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt >> >> — Gordon >> > Is there a similar technique that would allow calculation of the > alignment? (which is also required by the DWARF derived-type > descriptor.) There is more than one form of alignment. To find the struct field alignment of something, you can...

Does this help? http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt On 11 Nov 2012, at 10:52, edA-qa mort-ora-y <eda-qa at disemia.com<mailto:eda-qa at disemia.com>> wrote: Is there a way to get the size of a type in the IR assembly code? I know the size must be known since alloca and getelementptr both implicitly use it, but I don't see any w...

> This is almost exactly what you want to do. Please make the array be [0 x > int] though, as it is undefined in llvm to access past the end of an array > with non-zero length. I added a note about zero-length arrays here: > > http://llvm.cs.uiuc.edu/docs/LangRef.html#i_getelementptr > http://llvm.cs.uiuc.edu/docs/LangRef.html#t_array > > As you mention above, you

Hi: just like the c function sizeof(). I would avoid the usage of the c function call, and expect something like llvm intrinsic or some class providing this functionality. Does someone have experience in this? Thanks -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20100507/056bae50/attachment.html>

Chris Lattner wrote: > On Wed, 21 May 2008, Talin wrote: > >> On a related topic: The source-level debugging descriptors require you >> to know up front what the sizeof pointer types are. Is there any hope of >> the frontend remaining blissfully unaware of platform details? >> > > I really don't know how to do this. The current debug info stuff

On Sun, Aug 15, 2010 at 3:38 PM, Eric Christopher <echristo at apple.com> wrote: > > On Aug 15, 2010, at 2:34 PM, Nick Lewycky wrote: > >> Anton Korobeynikov wrote: >>> Hello >>> >>>> I just noticed that my union seems to look like an array....is that actually >>>> a union or do I have a problem somewhere? >>> Yes. Unions are

...If however the operands are all numerical values (eg the pointer operand is "null" and the others are numbers like "1") then it will be turned into a number by the optimizers. I think my case is stated above among your answer. http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt There is a brief document about using getelmentptr trick above. And I was wondering something similar to this case. %Size = getelementptr %T* null, int 1 %SizeI = cast %T* %Size to uint I understood that for this case, getelementptr will be collapsed to a number during optimization. It i...

Is there a way to get the size of a type in the IR assembly code? I know the size must be known since alloca and getelementptr both implicitly use it, but I don't see any way to get access to the size directly. I know my final compiler will have to get the size itself, but I'm just doing some simple tests directly in assembly now and am hoping there is an easy way to get the size of a

...From LLVM's point of view, the design I described could be interpreted as: "Implementing Portable sizeof, offsetof and Variable Sized Structures in LLVM" It's a random LLVM notes at: http://nondot.org/sabre/LLVMNotes/ http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt Basically the note wrote in there will solve main part of my problem, only another problem is structure field name need pass into IR file, I don't think it's a hard technical problem, we have choose many way to solve this, even put structure field name as comments into IR file. Look,...

...es. >> >> You can get equivalent behaviour in LLVM IR with the GEP trick[1] and >> alloca'ing the right about of space, but there's no way at all to make it >> match the API of a type. >> >> [1] - >> http://nondot.org/sabre/LLVMNotes/SizeOf-OffsetOf-VariableSizedStructs.txt > > That is what I was referring to, I know it would not be a single > instruction, but a CreateUnion in the IRBuilder or so could take a > list of types and so forth and find out the max in the IR using the > GEP trick an allocate an appropriate sized type that it returns for &g...