[compiler-rt][ARM] Only use bxaut when the target has pacbti #146057
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Most pacbti instructions are a nop when the target does not have pacbti, and thus safe to execute, but bxaut is an undefined instruction. When we don't have pacbti (e.g. if we're compiling compiler-rt with -mbranch-protection=standard in order to be forward-compatible with pacbti while still working on targets without it) then we need to use separate aut and bx instructions.
smithp35
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rlavaee
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…6057) Most pacbti instructions are a nop when the target does not have pacbti, and thus safe to execute, but bxaut is an undefined instruction. When we don't have pacbti (e.g. if we're compiling compiler-rt with -mbranch-protection=standard in order to be forward-compatible with pacbti while still working on targets without it) then we need to use separate aut and bx instructions.
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Most pacbti instructions are a nop when the target does not have pacbti, and thus safe to execute, but bxaut is an undefined instruction. When we don't have pacbti (e.g. if we're compiling compiler-rt with -mbranch-protection=standard in order to be forward-compatible with pacbti while still working on targets without it) then we need to use separate aut and bx instructions.