In RISCV's relocations, some relocations are comprised of two relocation types. For example, R_RISCV_PCREL_HI20 and R_RISCV_PCREL_LO12_I compose a PC relative relocation. In general the compiler will set a label in the position of R_RISCV_PCREL_HI20. So, to test the R_RISCV_PCREL_LO12_I relocation, we need decode instruction at position of the label points to R_RISCV_PCREL_HI20 plus 4 (the size of a riscv non-compress instruction).
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D105528
This patch is the initial support, it implements translation from object file to JIT link graph, and very few relocations were supported. Currently, the test file ELF_pc_indirect.s is passed, the HelloWorld program(compiled with mno-relax flag) can be linked correctly and run on instruction emulator correctly.
In the downstream implementation, I have implemented the GOT, PLT function, and EHFrame and some optimization will be implement soon. I will organize the code in to patches, then gradually send it to upstream.
Differential Revision: https://reviews.llvm.org/D105429
During the generic x86-64 support refactor in ecf6466f01 the implementation
of MachO_arm64_GOTAndStubsBuilder::isGOTEdgeToFix was altered to only return
true for external symbols. This behavior is incorrect: GOT entries may be
required for defined symbols (e.g. in the large code model).
This patch fixes the bug and adds a test case for it (renaming an old test
case to avoid any ambiguity).
Currently, BPF only contains three relocations:
R_BPF_NONE for no relocation
R_BPF_64_64 for LD_imm64 and normal 64-bit data relocation
R_BPF_64_32 for call insn and normal 32-bit data relocation
Also .BTF and .BTF.ext sections contain symbols in allocated
program and data sections. These two sections reserved 32bit
space to hold the offset relative to the symbol's section.
When LLVM JIT is used, the LLVM ExecutionEngine RuntimeDyld
may attempt to resolve relocations for .BTF and .BTF.ext,
which we want to prevent. So we used R_BPF_NONE for such relocations.
This all works fine until when we try to do linking of
multiple objects.
. R_BPF_64_64 handling of LD_imm64 vs. normal 64-bit data
is different, so lld target->relocate() needs more context
to do a correct job.
. The same for R_BPF_64_32. More context is needed for
lld target->relocate() to differentiate call insn vs.
normal 32-bit data relocation.
. Since relocations in .BTF and .BTF.ext are set to R_BPF_NONE,
they will not be relocated properly when multiple .BTF/.BTF.ext
sections are merged by lld.
This patch intends to address this issue by adding additional
relocation kinds:
R_BPF_64_ABS64 for normal 64-bit data relocation
R_BPF_64_ABS32 for normal 32-bit data relocation
R_BPF_64_NODYLD32 for .BTF and .BTF.ext style relocations.
The old R_BPF_64_{64,32} semantics:
R_BPF_64_64 for LD_imm64 relocation
R_BPF_64_32 for call insn relocation
The existing R_BPF_64_64/R_BPF_64_32 mapping to numeric values
is maintained. They are the most common use cases for
bpf programs and we want to maintain backward compatibility
as much as possible.
ExecutionEngine RuntimeDyld BPF relocations are adjusted as well.
R_BPF_64_{ABS64,ABS32} relocations will be resolved properly and
other relocations will be ignored.
Two tests are added for RuntimeDyld. Not handling R_BPF_64_NODYLD32 in
RuntimeDyldELF.cpp will result in "Relocation type not implemented yet!"
fatal error.
FK_SecRel_4 usages in BPFAsmBackend.cpp and BPFELFObjectWriter.cpp
are removed as they are not triggered in BPF backend.
BPF backend used FK_SecRel_8 for LD_imm64 instruction operands.
Differential Revision: https://reviews.llvm.org/D102712
MCJIT served well as the default JIT engine in lli for a long time, but the code is getting old and maintenance efforts don't seem to be in sight. In the meantime Orc became mature enough to fill that gap. The newly added greddy mode is very similar to the execution model of MCJIT. It should work as a drop-in replacement for common JIT tasks.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D98931
This option tells LLJIT to disable platform support explicitly: JITDylibs aren't scanned for special init/deinit symbols and no runtime API interposes are injected.
It's useful in two cases: for platforms that don't have such requirements and platforms for which we have no explicit support yet and that don't work well with the generic IR platform.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D99416
JITLink now requires section names to be unique. In MachO section names are only
guaranteed to be unique within their containing segment (e.g. a '__const' section
in the '__DATA' segment does not clash with a '__const' section in the '__TEXT'
segment), so we need to use the fully qualified <segment>,<section> section
names (e.g. '__DATA,__const' or '__TEXT,__const') when constructing
jitlink::Sections for MachO objects.
MCJIT served well as the default JIT engine in lli for a long time, but the code is getting old and maintenance efforts don't seem to be in sight. In the meantime Orc became mature enough to fill that gap. The newly added greddy mode is very similar to the execution model of MCJIT. It should work as a drop-in replacement for common JIT tasks.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D98931
When lli runs the below IR, it emits in-memory debug objects and registers them with the GDB JIT interface. The tests dump and check the registered information. IR has limited ability to produce complex output in a portable way. Instead the tests rely on built-in functions implemented in lli. They use a new command line flag `-generate=function-name` to instruct the ORC JIT to expose the built-in function with the given name to the JITed program.
`debug-descriptor-elf-minimal.ll` calls `__dump_jit_debug_descriptor()` to reflect the list of debug entries issued for itself after emitting the main module. The output is textual and can be checked straight away.
`debug-objects-elf-minimal.ll` calls `__dump_jit_debug_objects()`, which instructs lli to walk through the list of debug entries and append the encountered in-memory objects to the program output. We feed this output into llvm-dwarfdump to parse the DWARF in each file and dump their structures.
We can do the same for JITLink once D97335 has landed.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D97694
This reverts commit 6e58539659.
This failed in http://lab.llvm.org:8011/#/builders/123/builds/2676. I guess
were're still missing some symbols, but unfortunately the specific error is
masked by a bug in python/lit that hides stderr. This test will have to remain
disabled on Windows until I can get help to debug it further.
This testcase was failing on windows due to missing definitions. This commit
adds definitions of the missing symbols (as absolute symbols) to eliminate the
errors.
This test is failing on some windows bots with an error claiming that it is not
producing output. This appears to be a spurious failure, so I'm disabling on
windows while we investigate rather than reverting.
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.
Oneshot temporary labels for declaring function size can be omitted. Follow-up from D90331.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D90676
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
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
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 removes all legacy layers, legacy utilities, the old Orc C bindings,
OrcMCJITReplacement, and OrcMCJITReplacement regression tests.
ExecutionEngine and MCJIT are not affected by this change.
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
MachOLinkGraphBuilder has been treating these as hidden, but they should be
treated as local.
Symbols with N_PEXT set and N_EXT unset are produced when hidden symbols are
run through 'ld -r' without passing -keep_private_externs. They will show up
under 'nm -m' as "was private extern", hence the name of the test cases.
Testcase commited as relocatable object to ensure that the test suite doesn't
depend on having 'ld -r' available.
Correctly sign extend the addend, and fix implicit shift operand decoding
(it incorrectly returned 0 for some cases), and check that the initial
encoded immediate is 0.
The -phony-externals option adds a generator which explicitly defines any
otherwise unresolved externals as null. This transforms link-time
unresolved-symbol errors into potential runtime null pointer accesses
(if an unresolved external is actually accessed during execution).
This option can be useful in -harness mode to avoid having to mock a
large number of symbols that are not reachable at runtime (e.g. unused
methods referenced by a class vtable).
luxufan