[llvm] [BOLT] Add 'constant island' check in scanExternalRefs to prevent a crash when the function is disassembled fail or skipped (PR #165577)

[Gergely Bálint via llvm-commits]

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@@ -4,6 +4,7 @@
 # RUN: llvm-mc -filetype=obj -triple aarch64-unknown-unknown %s -o %t.o
 # RUN: %clang %cflags %t.o -pie -Wl,-q -o %t.exe
 # RUN: llvm-bolt %t.exe -o %t.bolt 2>&1 | FileCheck %s
+# RUN: llvm-bolt %t.exe -o %t.bolt -skip-funcs=caller 2>&1 | FileCheck %s
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bgergely0 wrote:

As the message printed by this patch is the same as the one in the previous patch, only adding this new RUN line works. 

However, I think it would be nice if you added a comment for this line, to explain that you are now checking for a message printed from another location (ScanExternalRefs). The logic of why skipping "caller" triggers the new check could also be documented here.

https://github.com/llvm/llvm-project/pull/165577