search for: bitlength

...it can know a lot more information about what > happens when bitcasting from one address space to another. This > doesn't have to go into TargetData. Well, if the pointers really are differently sized, you couldn't just bitcast between them, since bitcast requires values of equal bitlength? Or is this something that would only be exposed when doing intoptr/ptrtoint and simply assumed to be handled in the backend for pointer-to-pointer bitcasts? > > In this case, finding some text representation for the address space > > relations make sense, so that these relations can b...

...pt) Partitioning of seg registers is good for security but irrelevant in this example, both the code space and data space use identical management models. Methods: A sequential lookup table (turnary tree, reference table, "nibbler") is used for memory lookup using conventional infinite-bitlength identifiers using any size partition and turnary size... table has id1, it has 256 blocks (mem ptr or similar ID), value of turnary is n (of 8bit) and size of block is static per table. regardless of using id based lookups for data or memory locations, the process is identical: shift turnary scop...

On Jul 21, 2008, at 11:58 PM, Matthijs Kooijman wrote: >> >> You probably want to somehow extend TargetData to encode the address >> space descriptions, including pointer sizes and address space >> relationships. > Hmm, you have an excellent point there, pointer sizes could indeed > easily have > different sizes in different address spaces... That would make

I realize I am one of the few who uses the segment registers (especially CS and DS) on the ia32 chips for example, and a definite few with complete segregation models that rival specialized physical processors... GCC still fails to use these correctly and if your LLVM still depends on either Generic or some of the RTL models they use in various processor definitions, I express concern for

Hi Gordon, > TargetData is a concrete class, part of the middle-end. It describes > parts of the the target's ABI. It allows target-independent passes to > do things like decide whether x[1] and ((char *) x)[4] alias. This is > possible without actually linking with the code generator for the > relevant target. TargetData can be encoded in the LLVM IR, e.g. target

...e information about what >> happens when bitcasting from one address space to another. This >> doesn't have to go into TargetData. > Well, if the pointers really are differently sized, you couldn't > just bitcast > between them, since bitcast requires values of equal bitlength? Or > is this > something that would only be exposed when doing intoptr/ptrtoint and > simply > assumed to be handled in the backend for pointer-to-pointer bitcasts? I think it should be safe for instcombine to assume there is no truncation of pointers. If you have ptra -> pt...