[JITLink][AArch32] Add GOT builder and implement R_ARM_GOT_PREL relocations for ELF #78753
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✅ With the latest revision this PR passed the C/C++ code formatter. |
| # The +12 accounts for the ARM branch offset (8) and the .LPC offset (4), which | ||
| # is stored as initial addend inline. | ||
| # FIXME: We shouldn't need to substract the 64-bit sign-extension manually. | ||
| # jitlink-check: *{4}got_prel_offset = got_addr(out.o, target) - (got_prel + 12) - 0xffffffff00000000 |
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The offset is a signed 32-bit value and it doesn't get sign-extended to JITLink's 64-bit target address type. We should probably fix that, but it seems outside the scope of this PR.
…L relocations for ELF
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This patch implements a new relocation type and it's pretty straightforward. All new code is in JITLink AArch32 and exercised in a test that I adapted from an existing test in LLD. The pre-merge build failed due to MLIR test failures on Windows that are unrelated. The JITLink built went well and tests passed on both platforms. I have some more patches based on this and I want to land them before release/18.x branches. If there are any questions about the code here, I am happy to discuss post-commit. |
LLJIT needs this relocation for running deinitializers even if we stick to
-fno-piccode otherwise. I summarized the logic ofR_ARM_GOT_PRELin this gist based on a test in LLD: https://gist.github.com/weliveindetail/6dd33d43ea743d6e8a7399d1950c77b7