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Peter Smith
f86c48400e
Arm Architecture v8.5a introduces Branch Target Identification (BTI). When enabled all indirect branches must target a bti instruction of the appropriate form. As PLT sequences may sometimes be the target of an indirect branch and PLT[0] always is, a static linker may need to generate PLT sequences that contain "bti c" as the first instruction. In effect: bti c adrp x16, page offset to .got.plt ... Instead of: adrp x16, page offset to .got.plt ... At present the PLT decoding assumes the adrp will always be the first instruction. This patch adds support for a single "bti c" to prefix it. A test binary has been uploaded with such a PLT sequence. A forthcoming LLD patch will make heavy use of the PLT decoding code. Differential Revision: https://reviews.llvm.org/D62598 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362523 91177308-0d34-0410-b5e6-96231b3b80d8