================ @@ -660,42 +660,136 @@ Non-Integral Pointer Type Note: non-integral pointer types are a work in progress, and they should be considered experimental at this time. -LLVM IR optionally allows the frontend to denote pointers in certain address -spaces as "non-integral" via the :ref:`datalayout string<langref_datalayout>`. -Non-integral pointer types represent pointers that have an *unspecified* bitwise -representation; that is, the integral representation may be target dependent or -unstable (not backed by a fixed integer). +For most targets, the pointer representation is a direct mapping from the +bitwise representation to the address of the underlying memory allocation. +Such pointers are considered "integral", and any pointers where the +representation is not just an integer address are called "non-integral". + +Non-integral pointers have at least one of the following three properties: + +* the pointer representation contains non-address bits +* the pointer representation is unstable (may changed at any time in a + target-specific way) +* the pointer representation has external state + +These properties (or combinations thereof) can be applied to pointers via the +:ref:`datalayout string<langref_datalayout>`. + +The exact implications of these properties are target-specific. The following +subsections describe the IR semantics and restrictions to optimization passes +for each of these properties. + +Pointers with non-address bits +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Pointers in this address space have a bitwise representation that not only +has address bits, but also some other target-specific metadata. +In most cases pointers with a non-address bits behave exactly the same as an +integral pointer, the only difference is that it is not possible to create a +pointer just from an address unless all the non-address bits are also recreated +correctly in a target-specific way. +Since the address width such a pointer is not equal to the bitwise +representation, extracting the address will need to truncate to the index width +of the pointer. ---------------- nikic wrote:
This sentence is only true for ptrtoint, but not ptrtoaddr. Might make sense to just drop it. https://github.com/llvm/llvm-project/pull/105735 _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
