[llvm] [BOLT][BTI] Add needed BTIs in LongJmp or refuse to optimize binary (PR #171149)

[Paschalis Mpeis via llvm-commits]

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@@ -0,0 +1,38 @@
+/* This test checks that LongJmp can (not) add BTI instructions to PLT entries
+   when targeting them using stubs.
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paschalis-mpeis wrote:

The layout bolt bails out on is: plt immediately followed by original text, then after is data, and the new text is placed after data, causing the stub to PLT?

nit: could add one line to note this.

https://github.com/llvm/llvm-project/pull/171149