Summary: This operation is done every time we load a binary, this behavior should be moved into OpenMP since it concerns an OpenMP specific data struct. This is a little messy, because ideally we should only be using public APIs, but more can be extracted later.
This patch introduces libomptarget support for the ATTACH map-type, which can be used to implement OpenMP conditional compliant pointer attachment, based on whether the pointer/pointee is newly mapped on a given construct. For example, for the following: ```c int *p; #pragma omp target enter data map(p[1:10]) ``` The following maps can be emitted by clang: ``` (A) &p[0], &p[1], 10 * sizeof(p[1]), TO | FROM &p, &p[1], sizeof(p), ATTACH ``` Without this map-type, these two possible maps could be emitted by clang: ``` (B) &p[0], &p[1], 10 * sizeof(p[1]), TO | FROM (C) &p, &p[1], 10 * sizeof(p[1]), TO | FROM | PTR_AND_OBJ ```` (B) does not perform any pointer attachment, while (C) also maps the pointer p, which are both incorrect. In terms of implementation, maps with the ATTACH map-type are handled after all other maps have been processed, as it requires knowledge of which new allocations happened as part of the construct. As per OpenMP 5.0, an attachment should happen only when either the pointer or the pointee was newly mapped while handling the construct. Maps with ATTACH map-type-bit do not increase/decrease the ref-count. With OpenMP 6.1, `attach(always/never)` can be used to force/prevent attachment. For `attach(always)`, the compiler will insert the ALWAYS map-type, which would let libomptarget bypass the check about one of the pointer/pointee being new. With `attach(never)`, the ATTACH map will not be emitted at all. The size argument of the ATTACH map-type can specify values greater than `sizeof(void*)` which can be used to support pointer attachment on Fortran descriptors. Note that this also requires shadow-pointer tracking to also support them. That has not been implemented in this patch. This was worked upon in coordination with Ravi Narayanaswamy, who has since retired. Happy retirement, Ravi! --------- Co-authored-by: Alex Duran <alejandro.duran@intel.com>
This sprinkles a few mutexes around the plugin interface so that the olLaunchKernel CTS test now passes when ran on multiple threads. Part of this also involved changing the interface for device synchronise so that it can optionally not free the underlying queue (which introduced a race condition in liboffload).
The following patch introduces a new interop interface implementation with the following characteristics: * It supports the new 6.0 prefer_type specification * It supports both explicit objects (from interop constructs) and implicit objects (from variant calls). * Implements a per-thread reuse mechanism for implicit objects to reduce overheads. * It provides a plugin interface that allows selecting the supported interop types, and managing all the backend related interop operations (init, sync, ...). * It enables cooperation with the OpenMP runtime to allow progress on OpenMP synchronizations. * It cleanups some vendor/fr_id mismatchs from the current query routines. * It supports extension to define interop callbacks for library cleanup.
Previously we decided to check in files that we generate with tablegen. The justification at the time was that it helped reviewers unfamiliar with `offload-tblgen` see the actual changes to the headers in PRs. After trying it for a while, it's ended up causing some headaches and is also not how tablegen is used elsewhere in LLVM. This changes our use of tablegen to be more conventional. Where possible, files are still clang-formatted, but this is no longer a hard requirement. Because `OffloadErrcodes.inc` is shared with libomptarget it now gets generated in a more appropriate place.
[Offload] Use new error code handling mechanism This removes the old ErrorCode-less error method and requires every user to provide a concrete error code. All calls have been updated. In addition, for consistency with error messages elsewhere in LLVM, all messages have been made to start lower case.
A new ErrorCode enumeration is present in PluginInterface which can be used when returning an llvm::Error from offload and PluginInterface functions. This enum must be kept up to sync with liboffload's ol_errc_t enum, so both are automatically generated from liboffload's enum definition. Some error codes have also been shuffled around to allow for future work. Note that this patch only adds the machinery; actual error codes will be added in a future patch. ~~Depends on #137339 , please ignore first commit of this MR.~~ This has been merged.
Summary: Currently we depend on a single LLVM include directory. This is actually only required to define one enum, which is highly unlikely to change. THis patch makes the `Environment.h` include directory more hermetic so we no long depend on other libraries. In exchange, we get a simpler dependency list for the price of hard-coding `1` somewhere. I think it's a valid trade considering that this flag is highly unlikely to change at this point. @ronlieb AMD version https://gist.github.com/jhuber6/3313e6f957be14dc79fe85e5126d2cb3
If user specifies offload is disabled (e.g., OMP_TARGET_OFFLOAD=disable), disable library almost completely. This reduces resources spent to a minimum and ensures all APIs behave as if the only available device is the host device. Currently some of the APIs behave as if there were devices avaible for offload even when under OMP_TARGET_OFFLOAD=disable. --------- Co-authored-by: Joseph Huber <huberjn@outlook.com>