search for: unionlayout

...than defining a brand-new LLVM type, I think the best approach is to generalize the existing StructType. We can change the "isPacked" flag (which is stored in the SubclassData of the type) to a 3-valued enum called StructLayout, which has 3 members: UnpackedLayout, PackedLayout, and UnionLayout. After that, it's mostly a case of hunting down everywhere that calls "isPacked", and adding the appropriate case. :) > -Chris > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > h...

...and-new LLVM type, I think the best approach is to > generalize the existing StructType. We can change the "isPacked" flag > (which is stored in the SubclassData of the type) to a 3-valued enum > called StructLayout, which has 3 members: UnpackedLayout, PackedLayout, > and UnionLayout. > > After that, it's mostly a case of hunting down everywhere that calls > "isPacked", and adding the appropriate case. :) Hi Talin, thanks for looking in to this. I think there's already a lot of code that makes the assumption that the different members of a Struct...

On Dec 30, 2008, at 12:41 PM, Talin wrote: > I've been thinking about how to represent unions or "disjoint types" > in LLVM IR. At the moment, the only way I know to achieve this right > now is to create a struct that is as large as the largest type in > the union and then bitcast it to access the fields contained within. > However, that requires that the

I've been thinking about how to represent unions or "disjoint types" in LLVM IR. At the moment, the only way I know to achieve this right now is to create a struct that is as large as the largest type in the union and then bitcast it to access the fields contained within. However, that requires that the frontend know the sizes of all of the various low-level types (the