LFI Integrated Rewriter with X86 Support (LLVM 20) #4
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Adds the `aarch64_lfi`, `aarch64_lfi_stores` and `aarch64_lfi_jumps` subarches for AArch64. Reserves the necessary registers and disables compressed jump tables when targeting LFI.
This patch establishes the scaffolding for the LFI MC rewriter, based on the NaCl auto-sandboxing assembler. There is a generic MCLFIExpander, plus an AArch64-specific subclass where the rewriter will be implemented in a future patch.
When assembling a .s file using clang or llvm-mc, automatically run the LFI rewriter if targeting LFI.
Doesn't handle basic pre/post-indexed loads/stores yet.
There is a remaining corner case for certain instructions with hard-coded immediate offset values.
These directives make it possible to disable the LFI rewriter in GNU assembly.
Removes the aarch64_lfi_stores and aarch64_lfi_jumps target triples and replaces them with +lfi-stores and +lfi-jumps subtarget features for AArch64.
Also changes the instruction size estimate to include an additional guard instruction for loads/stores so that branch relaxation correctly resizes branches even before the expander is run.
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