This patch introduces generic x86-64 edge kinds, and refactors the MachO/x86-64
backend to use these edge kinds. This simplifies the implementation of the
MachO/x86-64 backend and makes it possible to write generic x86-64 passes and
utilities.
The new edge kinds are different from the original set used in the MachO/x86-64
backend. Several edge kinds that were not meaningfully distinguished in that
backend (e.g. the PCRelMinusN edges) have been merged into single edge kinds in
the new scheme (these edge kinds can be reintroduced later if we find a use for
them). At the same time, new edge kinds have been introduced to convey extra
information about the state of the graph. E.g. The Request*AndTransformTo**
edges represent GOT/TLVP relocations prior to synthesis of the GOT/TLVP
entries, and the 'Relaxable' suffix distinguishes edges that are candidates for
optimization from edges which should be left as-is (e.g. to enable runtime
redirection).
ELF/x86-64 will be refactored to use these generic edges at some point in the
future, and I anticipate a similar refactor to create a generic arm64 support
header too.
Differential Revision: https://reviews.llvm.org/D98305
This makes the target triple, graph name, and full graph content available
when making decisions about how to populate the linker pass pipeline.
Also updates the LLJITWithObjectLinkingLayerPlugin example to show more
API use, including use of the API changes in this patch.
This is required for ELF where PCRel32 doesn't implicitly subtract 4.
No test case yet: I haven't figured out a good way to test stub
generation -- this may required extensions to jitlink-check.
Adds the EHFrameSplitter and EHFrameEdgeFixer passes to the default JITLink
pass pipeline for ELF/x86-64, and teaches EHFrameEdgeFixer to handle some
new pointer encodings.
Together these changes enable exception handling (at least for the basic
cases that I've tested so far) for ELF/x86-64 objects loaded via JITLink.
PreFixupPasses better reflects when these passes will run.
A future patch will (re)introduce a PostAllocationPasses list that will run
after allocation, but before JITLinkContext::notifyResolved is called to notify
the rest of the JIT about the resolved symbol addresses.
Separates link graph creation from linking. This allows raw LinkGraphs to be
created and passed to a link. ObjectLinkingLayer is updated to support emission
of raw LinkGraphs in addition to object buffers.
Raw LinkGraphs can be created by in-memory compilers to bypass object encoding /
decoding (though this prevents caching, as LinkGraphs have do not have an
on-disk representation), and by utility code to add programatically generated
data structures to the JIT target process.
Basic implementation for call and jmp branches with 32 bit offset. Branches to local targets produce
Branch32 edges that are resolved like a regular PCRel32 relocations. Branches to external (undefined)
targets produce Branch32ToStub edges and go through a PLT entry by default. If the target happens to
get resolved within the 32 bit range from the callsite, the edge is relaxed during post-allocation
optimization. There is a test for each of these cases.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D90331
We have been producing R_X86_64_REX_GOTPCRELX (MOV64rm/TEST64rm/...) and
R_X86_64_GOTPCRELX for CALL64m/JMP64m without the REX prefix since 2016 (to be
consistent with GNU as), but not for MOV32rm/TEST32rm/...
Symbols with special section index SHN_COMMON (0xfff2) haven't been handled so far and caused an invalid section error.
This is a more or less straightforward use of the code commented out at the end of the function. I checked with the ELF spec, that the symbol value gives the alignment.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D89795
The difference is that the former are indirect and go to the GOT while the latter go to the target directly. This info can be used to relax indirect ones that don't need the GOT (because the target is in range). We check for this optimization beforehand. For formal correctness and to avoid confusion, we should only change the relocation kind if we actually apply the relaxation.
This re-applies e2fceec2fd with fixes. Apparently we already *do* support
relaxation for ELF, so we need to make sure the test case allocates a slab at
a fixed address, and that the R_X86_64_REX_GOTPCRELX test references an external
that is guaranteed to be out of range.
This patch enables basic BSS section handling, and improves a couple of error
messages in the ELF section parsing code.
Patch by Christian Schafmeister. Thanks Christian!
Differential Revision: https://reviews.llvm.org/D88867
`ELFFile<ELFT>` has many methods that take pointers,
though they assume that arguments are never null and
hence could take references instead.
This patch performs such clean-up.
Differential revision: https://reviews.llvm.org/D87385
Summary: This adds the basic support for GOT in elf x86.
Was able to just get away using the macho code by generalising the edges.
There will be a follow up patch to turn that into a generic utility for both of the x86 and Mach-O code.
This patch also lands support for relocations relative to symbol.
Reviewers: lhames
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83748
Summary:
Adding in our first relocation type, and all the required plumbing to support the rest in following patches
Differential Revision: https://reviews.llvm.org/D80613
Reviewer: lhames
This patch adds a jitlink pass, 'registerELFGraphInfo', that records section
and symbol information about each LinkGraph in the llvm-jitlink session object.
This allows symbols and sections to be referred to by name in llvm-jitlink
regression tests. This will enable a testcase to be written for
https://reviews.llvm.org/D80613.
This initial implementation supports section and symbol parsing, but no
relocation support. It enables JITLink to link and execute ELF relocatable
objects that do not require relocations.
Patch by Jared Wyles. Thanks Jared!
Differential Revision: https://reviews.llvm.org/D79832
Lang Hames