Summary:
A previous patch added support for dumping offloading sections. The
tests for this feature added dummy input to the required section using
`llvm-objcopy`. This binary format has a required alignment of `8` which
was not being respected by the file copied with llvm-objcopy and would
cause failures on architectures sensitive to alignment problems or with
sanitizers. This patch adds the proper alignemnt and adds an error check
at least for the binary format so it's not completely opaque. This
should be improvbed so users actually get a helpful message.
Summary:
This patch adds some new sanity checks to make sure that the sizes of
the offsets are within the bounds of the file or what is expected by the
binary. This also improves the error handling of the version structure
to be built into the binary itself so we can change it easier.
Summary:
When writing the offload binary, we use a SmallVector. We already know
the size that we expect the buffer to take up so we should reserve all
that memory up-front to improve performance. Also this patch adds some
extra sanity checks for the binary format for safety.
Summary:
The OffloadingBinary uses a convenience struct to help manage the memory
that will be serialized using the binary format. This currently uses a
reference to an existing buffer, but this should own the memory instead
so it is easier to work with seeing as its only current use requires
saving the buffer anyway.
Summary:
The OffloadBinary wraps around an embedded device image, commonly an ELF
or LLVM BC file. These file formats have alignment requirements for
parsing, so if the image is stored at an un-aligned offset from the
beginning of the file we will be unable to parse the embeded image
without copying the image buffer. This patch adds alignment padding
before the binary image is appended to ensure we can parse the symbolic
file it contains in-place without copying memory.
We use the `OffloadBinary` to create binary images of offloading files
and their corresonding metadata. This patch changes this to inherit from
the base `Binary` class. This allows us to create and insepect these
more generically. This patch includes all the necessary glue to
implement this as a new binary format, along with added the magic bytes
we use to distinguish the offloading binary to the `file_magic`
implementation.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D126812
We need to embed certain metadata along with a binary image when we wish
to perform a device-linking job on it. Currently this metadata was
embedded in the section name of the data itself. This worked, but made
adding new metadata very difficult and didn't work if the user did any
sort of section linking.
This patch introduces a custom binary format for bundling offloading
metadata with a device object file. This binary format is fundamentally
a simple string map table with some additional data and an embedded
image. I decided to use a custom format rather than using an existing
format (ELF, JSON, etc) because of the specialty use-case of this. We
need a simple binary format that can be concatenated without requiring
other external dependencies.
This extension will make it easier to extend the linker wrapper's
capabilties with whatever data is necessary. Eventually this will allow
us to remove all the external arguments passed to the linker wrapper and
embed it directly in the host's linker so device linking behaves exactly
like host linking.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D122069
Joseph Huber