Summary: The OpenMP handling using an offload binary should be optional, it's only used for extra metadata for llvm-objdump. Also the triple was completely wrong, it didn't let anyone correctly choose between ELF and COFF handling.
This patch adds an Offload Wrapper for the SYCL kind. This is an essential step for SYCL offloading and the compilation flow. The usage of offload wrapping is added to the clang-linker-wrapper tool. Modifications: Implemented `bundleSYCL()` function to handle SYCL image bundling. Implemented `wrapSYCLBinaries()` function that is invoked from clang-linker-wrapper. SYCL Offload Wrapping uses specific data structures such as `__sycl.tgt_device_image` and `__sycl.tgt_bin_desc`. Each SYCL image maintains its own symbol table (unlike shared global tables in other targets). Therefore, symbols are encoded explicitly during the offload wrapping. Also, images refer to their own Offloading Entries arrays unlike other targets. The proposed `__sycl.tgt_device_image` uses Version 3 to differentiate from images generated by Intel DPC++. The structure proposed in this patch doesn't have fields deprecated in DPC++.
The module currently stores the target triple as a string. This means
that any code that wants to actually use the triple first has to
instantiate a Triple, which is somewhat expensive. The change in #121652
caused a moderate compile-time regression due to this. While it would be
easy enough to work around, I think that architecturally, it makes more
sense to store the parsed Triple in the module, so that it can always be
directly queried.
For this change, I've opted not to add any magic conversions between
std::string and Triple for backwards-compatibilty purses, and instead
write out needed Triple()s or str()s explicitly. This is because I think
a decent number of them should be changed to work on Triple as well, to
avoid unnecessary conversions back and forth.
The only interesting part in this patch is that the default triple is
Triple("") instead of Triple() to preserve existing behavior. The former
defaults to using the ELF object format instead of unknown object
format. We should fix that as well.
Summary: The previous offloading entry type did not fit the current use-cases very well. This widens it and adds a version to prevent further annoyances. It also includes the kind to better sort who's using it. The first 64-bytes are reserved as zero so the OpenMP runtime can detect the old format for binary compatibilitry.
Follow up to https://github.com/llvm/llvm-project/issues/123569
Summary: Previously, managed variables didn't work in rdc mode using the new driver because we just didn't register them. This was previously ignored because we didn't have enough space in the current struct format. This patch amends that by just emitting a struct pair for the two variables and using the single pointer. In the future, a more extensible entry format would be nice, but that can be done later.
This patch overhauls the `libomptarget` and plugin interface. Currently, we define a C API and compile each plugin as a separate shared library. Then, `libomptarget` loads these API functions and forwards its internal calls to them. This was originally designed to allow multiple implementations of a library to be live. However, since then no one has used this functionality and it prevents us from using much nicer interfaces. If the old behavior is desired it should instead be implemented as a separate plugin. This patch replaces the `PluginAdaptorTy` interface with the `GenericPluginTy` that is used by the plugins. Each plugin exports a `createPlugin_<name>` function that is used to get the specific implementation. This code is now shared with `libomptarget`. There are some notable improvements to this. 1. Massively improved lifetimes of life runtime objects 2. The plugins can use a C++ interface 3. Global state does not need to be duplicated for each plugin + libomptarget 4. Easier to use and add features and improve error handling 5. Less function call overhead / Improved LTO performance. Additional changes in this plugin are related to contending with the fact that state is now shared. Initialization and deinitialization is now handled correctly and in phase with the underlying runtime, allowing us to actually know when something is getting deallocated. Depends on https://github.com/llvm/llvm-project/pull/86971 https://github.com/llvm/llvm-project/pull/86875 https://github.com/llvm/llvm-project/pull/86868
Caused failures on build-bots, reverting to investigate. This reverts commit 80f9e814ec896fdc57ee84afad8ac4cb1f8e4627.